5000 Oilfield Terms Part 1
Extended Reach Well or ERW
A well deviated above the pay to reach further from the drill site or further into the pay formation to expose my contact area with the pay zone.
Extension Well
A well drilled on the edge of the existing field that may extend the known area of the field.
Flapper Valve
A one-way, flow actuated valve common in safety valves, coiled tubing and fluid loss devices.
Angular Unconformity
An unconformity in which the beds below the unconformity dip at different angles than the beds above it.
AG
Arabian Gulf.
EPA
Environmental Protection Agency, US pollution control enforcer.
Coarse
API designation of sand-type particles larger than 2000 microns.
Chlorine Dioxide
ClO2, a free radical compound especially useful in killing bacteria in waters. It is a powerful biocide that dissolves biomass cell walls. It is nearly impossible for bacteria to develop immunity against ClO2.
CAA
Clean Air Act.
AIP
Australian Institute of Petroleum.
AAPEA
Australian Petroleum Production and Exploration Association.
AFE (expense)
Authority for Expenditure on a well (authorized funds for drilling or workover).
Barium Sulfate (scale)
BASO4 scale is produced in the well and in facilities as the result of precipitation when incompatible waters (one having Ba ion and the other SO4 ion) are mixed or when the equilibrium of the flowing fluid reduced and a precipitate is triggered by over saturation or a physical upset. May also be associated with radioactivity or NORM scale when a radium or uranium isotope is part of the crystalline lattice structure.
BHI
Baker Hughes INTEQ.
BOT
Baker Oil Tools.
BS
Basic Sediment and Water or BS&W: the solids and water entrained in crude oil.
BS&W
Basic Sediment and Water. The solids and water entrained in crude oil.
Bc (drilling)
Bearden units of consistency.
Behind Pipe Reserves
Behind-pipe reserves are expected to be recovered from zones in existing wells, which will require additional completion work or future recompletion prior to the start of production.
BiC
Best in Class.
BP (well plugging)
Bridge Plug.
BSI
British Standards Institute.
BTU
British Thermal Unit.
BJ
Byron Jackson Service Company.
Casing Collar Log
CCL, a downhole log recording, given by magnetic deflection, of the location of couplings or other equipment.
Carboxy Methyl Cellulose
CMC, a modified cellulose polymer used in drilling fluids.
Carbonic Acid
CO2 and water. A common corrosion source in wells.
Corrosion Resistant Alloy
CRA, alloy intended to be resistant to general and localized corrosion of oilfield environments.
Calcium Hydroxide
Ca(OH)2, slaked lime.
Calcium Bromide
CaBr2, water soluble brine weighting agent.
Calcium Carbonate
CaCO3, limestone, a common formation or when in particles, a weighting or fluid loss agent.
Calcium Chloride
CaCl2, a water soluble brine weighting agent.
Calcium Oxide
CaO, quick lime.
Anhydrite
CaSO4 formation. Usually formed as an evaporite from a drying lake of trapped sea water.
CGA
Canadian Gas Association.
CIM
Canadian Institute of Mining
CHGP
Cased Hole Gravel Pack.
CVT
Chevron Texaco.
ABS (plastic)
Acrylonitrile-Butadiene-Styrene.
ANGTS
Alaska Natural Gas Transportation System.
AWGRS
Alaska well's group reporting system.
ALG
Algerian.
AAODC
American Association of Oilwell Drilling Contractors.
AAPG
American Association of Petroleum Geologists.
AAPL
American Association of Petroleum Landmen.
ABS
American Bureau of Shipping.
ACS
American Chemical Society.
AGA
American Gas Association.
AIME
American Institute of Mining, Metallurgical and Petroleum Engineers.
AIPG
American Institute of Professional Geologists.
ANSI
American National Standards Institute.
ANGA
American Natural Gas Association
API
American Petroleum Institute.
ASME
American Society of Mechanical Engineers.
ASTM
American Society of Testing Materials
Elbow
An "L" shaped fitting in surface piping.
Depreciation, Normalized
An accounting method under which Net Income includes charges or credits equal to the decreases or increases in current taxes on income, arising from the use of liberalized depreciation or accelerated amortization for tax purposes instead of the straight-line method. The contra entries for such charges to Net Income are suspended in Balance Sheet accounts. In future years, there is a feedback of these suspended amounts to Net Income when increases in the then current taxes on income occur because liberalized depreciation or accelerated amortization was used for tax purposes in prior years (From AGA).
Depreciation, Flow Through
An accounting procedure under which current Net Income reflects decreases or increases in current taxes on income, arising from the use of liberalized depreciation or accelerated amortization for tax purposes instead of the straightline method. See DEPRECIATION, NORMALIZED (From AGA).
External Filter Cake
filtration control established on the surface of the wellbore by particles large enough to bridge on the entry of the pores.
FCP
final circulating pressure.
Class C Cement
finer grind cement, higher early strength.
FRC
fire retardant clothing.
FCTA (brine)
first crystal to appear.
Centrifugal Pump
pump with an impeller or rotor that spins in a housing and the drag forces on the fluids cause them to flow.
Frangible Valve
purposely breakable valve, usually a flapper in a fluid loss device.
FN
fishing neck.
Flying Leads (subsea)
flexible hydraulic hoses connected to control systems in a subsea tree.
FPU
floating production unit.
FPSO
floating production, storage and offloading. An alternative to pipelines.
Cross Flow
flow between formations via a connected wellbore. Crossflow, as seen by downhole cameras, can occur with the wellbore full of fluid and the appearance of a dead well at surface.
Flow Regime
flow condition (e.g., mist, slug, churn, etc.) of a multiphase process stream.
FL (operations)
flow line.
Bubble Flow
flow of liquids enabled by the rise of gas bubbles in a well.
Flow Back
flowing a well back after a treatment.
FBHP
flowing bottom hole pressure.
FGOR
flowing gas oil ratio.
Belching
flowing slugs of material.
Dean Number
fluid flow effects in spooled tubing.
Bridging Material
fluid loss control material that bridges against the leakoff site.
FLC (completions)
fluid loss control.
FL (drilling/completions)
fluid loss.
Clean Circulation (drilling)
fluids returning to the surface without cuttings or other solids removed from the well.
Dispersed
fluids with materials added to disperse solids or flocs.
FKM
fluoro-elastomers (VitonTM, FluorelTM, etc.).
FC
fluorocarbon. A aromatic resistant seal material.
FEPM
fluoroelastomers (AflasTM, etc.)
Bullheading
forcing fluids in the pipe into the formation at a pressure higher than the pore pressure and sometimes higher than the fracturing breakdown pressure. Used to displace a kick out of the pipe when wellbore and wellhead pressure limits permits.
Absorption Gasoline
gasoline extracted from wet natural gas by putting the gas in contact with oil.
Fast Gauges
gauges with a high sampling rate.
Cut-Off tool
generally a reference to a device that severs the pipe downhole by explosive, chemical, heat or mechanical action.
Crown Lands
government owned land.
Departure Curves
graphs that show influence of a variable on the basic measurement; e.g., temperature, hole diameter, mud resistivity, bed thickness, adjacent bed resistivity, etc.
Cluster Perforating
grouping the perforations in small groups usually to generate multiple, regularly spaced fractures using hydraulic diversion or ball sealers (etc.).
Calcium Sulfate
gyp or anhydrite, CaSO4.
Bomb Hanger
hanger for bottom-hole pressure recorder (bombs).
Corrosion Film
First products of corrosion films that may form a tight, barrier film and reduce further corrosion.
After Cooler
heat exchangers for cooling gas after compression.
Convection Heat Transfer
heat transfer by gas, steam or liquid circulation. Heat transport by moving particles and the thermal energy they carry to a new location.
Conduction Heat Transfer
heat transfer when two solids are in contact and heat passes between them - heat transport by direct transfer of energy from one particle to another.
Carburizing
heat-treating process where carbon is introduced into a solid iron alloy by heating above transformation temperature range while in contact with a carbonaceous material (solid, liquid, or gas form of carbon). Usually quenched to produce a hardened outer shell.
Dirty
high clay content or higher natural radioactivity signature on the gamma-ray log.
Crown
high point.
Class E and F Cements
high temperature cements.
Draw Works
hoisting mechanism on a drilling rig.
Associated Liquids
hydrocarbon condensates produced in conjunction with natural gas.
Deferred Production
hydrocarbon production that is delayed due to any of several reasons, specifically well repairs, restrictions that curtail production, regulations, etc.
Flow Efficiency
ideal drawdown / actual drawdown.
Cathodic Protection
impressed current that offsets the current produced in a corrosion cell and reduces corrosion.
Bitumen
pyrogeneous, essentially non reactive, hydrocarbon. Most bitumen is not considered as movable through the reservoir under normal conditions of flow unless heated.
Core Analysis
lab work on a core sample that may yield permeability, porosity, pore size distribution, grain size, density, etc.
Commingle
mixing production. In a well, when two or more zones are mixed to assist in economic production. In a flow line, when multiple crude source streams are mixed.
Deltas
mouth of river deposits, usually fan shaped with significant variation in composition, sorting and thickness. Quality of the reservoir rock may vary widely.
Casing Reciprocation
movement of casing up and down to help remove mud and replace it with cement slurry.
Clay Migration
movement of clay particles, usually after partial disintegration of the clay matrix due to absorption of water or reaction to other effects such as ions, velocity, crushing due to overburden, etc.
Fingering
movement of one fluid through another.
Fines Migration
movement of small particles (usually <5 microns) through the rock pores.
Casing Centralizer
one of several centralizer designs intended to keep the casing better centered in the borehole to get better cement jobs.
FeSx
one of several forms of iron sulfide.
Formate
one of several low damage, low toxicity, normally high cost brine for special applications. May be one of several formation compounds.
Foam Breaker
one of several materials that reduce the stability of the bubble skin in a foam and cause the foam to break.
Embedment
proppant that has partly or completely sunk into a formation through displacement of the formation around the grain.
Formation Gas-Oil Ratio
quantity of oil dissolved in one stock tank barrel of oil at current reservoir pressure and temperature.
Extrusion Gap
radial gap between the maximum rated casing ID and the minimum OD immediately adjacent to the packing element.
Alpha Decay
radioactive decay process where the loss of an alpha particle from the nucleus lowers the atomic number by two and the atomic mass by four.
Bend Radius
radius of curvature of flexible pie measured to the pipe centerline.
Bottom Out
reach final drilling depth.
Bump The Plug
reaching bottom with the plug during a cementing operation or fluid displacement operation.
Bacterial Oxidation and Reduction
reactions involving aerobic decay, organic matter oxidation, fermentation, anaerobic decay, etc.
Chemical Dissolution
reactions involving the rock and connate fluids in which parts of the matrix are filled by scale or mineral growths or removed and become high permeability flow channels.
Depletion
reducing the fluid content of a formation by production of that fluid.
Casing Wear
reduction in thickness x 100 / original thickness. Most common wear is from rotating strings during drilling.
Dissociation Porosity
secondary porosity that is created when solid materials in sediment dissolve in interstitial solutions.
CO2 Injection
secondary recovery technique for oil. The carbon dioxide gas is injected and alternated with water. CO2 lowers the viscosity of most oils, but may trigger severe asphaltene and scale precipitates.
Button-Up
secure the well or close in.
Chemical Sediment
sediment formed by precipitation from water, e.g., salt from dehydration and scales.
Coal
sedimentary rock, often highly naturally fractured, composed of thermally modified plant remains.
AOF
see Absolute Open Flow. The maximum rate that a well can produce at the lowest possible bottom hole pressure (usually figured with a gas gradient).
CT
see Coiled Tubing.
Depreciation, Accelerated
see Depreciation, Liberalized.
EU or EUE
see External Upset.
FPC
see Free Point Constant. Used in stuck pipe depth calculations.
Circulation Charge
see Puncher Charge.
E-Line
see electrical line.
Confusion Block
see impression block.
Compartments
segregated flow units of a main reservoir that have a poor flow connection or no flow connection to the main reservoir.
Air Gun
seismic source for ocean seismic work.
Doodlebug
seismograph.
B Profile
seldom used name for a SSSV profile.
Dealloying (corrosion)
selective corrosion of one metal in an alloy.
Compartmentalization
separate compartments or smaller reservoirs in a larger, common reservoir that may not be in communication.
Break an Emulsion
separate the emulsion into its components.
Divergence
separation of groups of data from either other or from a norm.
Dewatering (fluids separation)
separation of liquids and solids in the general sense. Also, removing water from hydrocarbon streams.
Critical Velocity (erosion)
setting a maximum flow rate to minimize erosion corrosion.
Composite Log
several logs spliced or overlayed to form a single group log record.
Armor
shielding over a cable or other device that needs to be protected from crushing.
Diatomaceous Earth
silica particles from Diatom beds. Used as a filtering media and as an additive to cement.
Agate
siliceous rock with alternating bands of chalcedony and colored chert.
Checking (corrosion)
slight breaks in a surface coating that do not penetrate to the underlying surface.
Double Grip (packer)
slips that prevent either upward or downward movement.
FIT (operations)
Formation Integrity Test.
Free Point and Backoff
Free Point analysis followed by downhole unscrewing of a pipe coupling above the stuck point.
Casing-Annular Pressure
Pressure in the annulus between the tubing O.D. and the casing I.D.
Abandonment Pressure
The minimum pressure of the reservoir when the wells are abandoned.
Drill Bit
The rock cutting device at the bottom of the drill string.
BLM
US Bureau of Land Management.
DOE
US Department Of Energy.
Attenuation
When a form of energy is propagated through a medium, its amplitude (energy level) is decreased. This decrease is termed attenuation.
Ball-Out
When using ball sealers, to effectively shut-off the entire zone and cause pressure to rise sharply.
DGMK
German Society for Petroleum and Coal Science and Technology.
Carboxyl Methyl, Hydroxy Methyl Cellulose
HEC, an anionic water soluble polymer used in various fluids. Can be relatively clean breaking under the right conditions.
Cement Retarder
a chemical additive such as lignosulfonate, salt in low concentration or most muds that slow down the cement.
Demulsifier
a chemical additive, usually a surfactant, that helps break emulsions.
Compton Scattering
a gamma-ray reaction in which the gamma-ray, after colliding with an electron, shifts some energy to the electron. The higher the energy loss by Compton scattering in a zone, the higher the electron concentration or density. The basis for the density log.
Annular Blowout Preventer
a device installed above or below the BOP that is capable of sealing around any device, and even on itself if the wellbore is empty.
Flow Divider (screen)
a device on the entrance to a screen to route the incoming flow more evenly across the face of the screen.
Boot Sub
a device run in the drill string just above the mill to catch cuttings.
Ball Dropper
a device that injected balls into the flowing treating fluid downstream of the high pressure pump.
Crown Saver
a device that keeps the traveling block from being raised ito the crown block.
Annular Packoff
a device that seals the annulus to pressure or flow.
Cyclone
a device that separates cuttings by centrifugal motion of the fluids.
Centrifuge
a device that separates materials by density through a centrifugal motion.
Eductor
a device that through flow of a power fluid through a nozzle, creates a low pressure area useful for moving fluids.
Fluoroscope
a device that uses a black light for identifying hydrocarbons on cuttings.
Actuator
a device that, by remote influence, can operate valves or other equipment.
Densitometer
a device used for reading the density of a flowing fluid or slurry.
Basket or Basket Sub
a device used to catch debris in the wellbore. Often a part of the string.
Choke
a device used to create a controlled pressure drop and allow some expansion of the gas. A choke holds a back pressure on the well fluids, controlling the expansion rate of the gas. It is useful for optimizing natural gas lift in oil wells with sufficient gas to flow naturally or in some gas lifted wells.
Broach
a device used to reround slightly collapsed tubulars.
Cold Finger Test
a device with a chilled probe that measures the temperature at which paraffin will precipitate of an oil solution.
Chisel Bit
a device with a single bit running the width of the hole. Also called a dove-tail bit.
Bird
a device with moveable vanes attached to an under water seismic streamer.
Consistometer
a device with rotating paddles, used to check the pumpability and set time of cement slurries.
Anchor
a device with slips that holds equipment in the wellbore.
Compression-Ignition Engine
a diesel engine; an engine in which the air and fuel are ignited by the heat produced on the compression stroke.
Diesel #1
a diesel fuel, C10-C14+ typically. #1 Diesel has paraffins removed for cleaner operation or cold weather use.
Colloidal Suspension
a dispersion of fine particles, held by charge or other force in a stable suspension.
Era
a division of geologic time, next shorter than the eon and larger than a period.
Annular Safety Valve
a downhole safety valve that shuts off the annulus.
Casing Scraper
a downhole tool with scraping teeth and brushes that is used to remove perforating burrs, "lipped down" areas in connection pins and remove mill scale, dried mud or cement, pipe dope and other well completion debris.
Casing Roller
a downhole tool, commonly run on pipe to try to reform the casing after a partial collapse.
Circulation Valve
a downhole valve in the treating string, operated by pressure pulsing or wireline that will allow the annulus to be circulated.
Fishtail Bit
a drag bit with no moving parts, rotated like a conventional metal drilling bit.
Antiwhirl Bit
a drill bit that, by its cutter placement, causes the bit to be forced against the side of the hole.
Bit
a drill bit, commonly either a roller cone, button bit, PDC, diamond or drag bit, used with a rotary string or a mud motor to drill through rock.
EZSVTM
a drillable bridge plug.
Cast Iron Bridge Plug
a drillable plug that can be quickly and reliable set to isolate a section of the well.
Clay Extender
a drilling additive to increase the viscosity of water based muds gelled with bentonite.
Choke Line
a drilling and workover pressure control device. A line that attached to the BOP stack and through which kick fluids can be circulated when the BOP is closed.
Electric Rig
a drilling rig where the power source is electricity provided by a generator.
Compaction Drive
a drive mechanism in a weak zone that displaces fluid by reducing the overall volume of the formation.
Duster
a dry hole.
Compensated Formation Density Log
a dual spacing formation density log, using two detectors at different distances from the source.
Butane
a four carbon chain alkane, may be a liquid in the reservoir, but vaporizes as pressure is released. Part of the natural gas liquid components.
Flow Cross
a four-way connection. In a wellhead, a flow cross connects the master valve and the swab valve with two, normally horizontal, connections to the wing valves.
Carried Interest
a fractional working interest in an oil and gas lease that arises from a deal between co-owners.
Brittle Fracture
a fracture created with little or no plastic deformation.
Burst Disk
a frangible disk designed to release pressure at a specific level.
Bunker C Oil
a fuel oil, normally with high sulfur and high viscosity. API gravity of about 10.5o. Also called Navey Heavy and Number 6 fuel oil.
Drill Pipe Safety Valve
a full opening valve with threads that match the drill pipe that can be quickly screwed onto the pipe to help control fluid flow up the tubing.
Bell Nipple
a funnel shaped pipe at the top of the casing that guides tool string entry and may have a side port for fluid pumping.
Delayed Gamma Ray
a gamma ray that is emitted from the decay of an excited state in a nuclear reaction.
FERC
Federal Energy Regulatory Commission (US gov. agency).
Biogenic Theory
a theory of petroleum formation in which the petroleum is thought to have originated from plant and animal material that has undergone transformation from deep burial.
ATV
all terrain vehicle.
Chemical Weathering
all the chemical reactions that act on rocks to produce stable minerals.
Drill String
all the equipment in a drilling BHA plus the drill pipe.
AASP
allowable annular surface pressure.
AFUDC
allowance for funds used during construction.
Face Seal
allowing a flat, usually polished, face to deform an elastomer and create a seal.
AHD (depth)
along hole depth or measured depth.
Alum
aluminum and potassium sulfate compound. Used was water clairfying.
Amines
ammonia based materials (NH3), in which one of more of the hydrogen atoms are replaced by hydrocarbons.
Contingency String (casing design)
an "extra" string in a casing design that can be used in the event of failure to get an upper string to the correct depth.
Electric Submersible Pump
an ESP or dowhole artifical lift unit powered by electricity..
Bound Fluid Log
an NMR log that measures bound fluid volume.
False Set
an abnormal early thickening of cement which does not affect the length of time which the cement can be pumped.
Blast Joint
an abrasion and erosion resistant tube that is run where ever direct sand impingement is a problem.
Fracture FinderTM Log
an acoustic log that helps determine if fractures are present.
Adaptor Spool
an adaptor that allows BOP's to be connected to wellhead flanges of various sizes.
Cement Accelerator
an additive such as calcium chloride, and salt in high concentrations that speeds the set of cement.
Chromatogram
an analysis of hydrocarbons from a gas stream in order of molecular size.
CEC
cation exchange capacity.
CBL
cement bond log.
CBT
cement bond tool.
CEL
cement evaluation log.
CET
cement evaluation tool.
Expanding Cement
cement with additives that promote volumetric cement expansion.
Fiber Cement
cement with small hair like fibers that build strength or help control fluid loss.
Cmt
cement.
CST (fluids)
centistokes. A measure of viscosity.
CGF
central gas facility.
CPS
central power station.
CWTF
central water treatment facility.
Certs
certificates, usually on physical or chemical properties (e.g., MSDS Sheets).
CsCOOH
cesium formate.
Bridging
collection of materials, usually from the formation that interlocks at some point in the well, often in the annulus and may stop flow or stick the pipe in place.
CMIT - IAxOA
combination mechanical integrity test - inner annulus by outer annulus.
CMIT - TxIAxOA
combination mechanical integrity test - tubing x inner annulus by outer annulus.
CMIT - TxIA
combination mechanical integrity test - tubing x inner annulus.
CDP
common depth point.
CMP (depth)
common mid point.
Calibration
comparison to a standard and adjustment to fit.
CDR (logging)
compensated dual resistivity.
CDL
compensated formation density log.
Erosion Corrosion
corrosion acceleration by passage of a high velocity flow or impingement of solids. May remove the thin, protective oxide film that protects exposed metal surface.
CIT (corrosion)
corrosion inhibitor treatment.
Filiform Corrosion
corrosion occurring under a coating in a pattern of filaments. May resemble threads.
Deposit Attack
corrosion occurring under or around a deposit on a surface.
Ecorr
corrosion potential.
CRA
corrosion resistant alloy.
Flow Assisted Corrosion
corrosion that is accelerated by the effects of erosion removing the initial corrosion films.
Cathodic Corrosion
corrosion, usually of an amphoteric metal, with a basic fluid.
Capital cost or expenditure
costs that apply to building or acquiring a capital asset.
COPAS (accounting)
council of petroleum accounting and shipping.
CEQ
council on environmental quality.
Chloride Stress Cracking
cracking of a metal under combined action of tensile stress and corrosion in the presence of chlorides and an electrolyte (NACE). Starts at a pit, scratch or notch. Crack proceeds primarily along grain boundaries. The cracking process is accelerated by chloride ions and lower pH.
Fracture Acidizing
creating a fracture in a carbonate and etching the face of the fracture to preserve flow capacity down the fracture.
CBHFP (rock mechanics)
critical bottom hole flowing pressure; a measurement of sanding potential of the formation.
CDP (rock mechanics)
critical drawdown pressure; maximum drawdown pressure for sand free rate.
CFR
critical flow rate.
CPT (corrosion)
critical pitting temperature.
CRP (rock mechanics)
critical reservoir pressure for sanding appearance.
Dead Oil
crude oil without gas. May have been degassed mechanically or by gas breakout during storage.
CQG
crystal quartz gauge.
Dolomite Rhombohedrials
crystals of dolomite in the pore space. May turn loose when acidized and become migrating fines.
CFH
cubic feet per hour.
Cfd
cubic foot per day.
Discordant
cutting across surrounding strata.
Cut and Strip
cutting the logging cable and threading it through the drill pipe when fishing for logging tools.
CRI (solids handling)
cuttings reinjection.
CSS
cyclic steam stimulation.
Area-to-Volume Ratio (pore/frac volume)
exposed area of a pore or fracture to the volume of fluid in the pore or fracture.
ERD
extended reach drilling.
ERW
extended reach well.
ECP
external casing packer.
EGP
external gravel pack.
Collapse Pressure
external hydrostatic pressure that will cause the onset of pipe yielding. Heavily influenced by tension loads on the pipe.
EOP
extreme overbalanced perforating.
Fanning Equation (or friction factor)
fF = (db/2V2) (P/L). Where = density (ppg), V = avg. fluid velocity (ft/sec), P is pressure loss over length L (ft).
FE
facility engineer.
FMECA
failure mode and criticality effects analysis
FMEA
failure mode and effects analysis.
Critical Failure
failure of an equipment unit that causes and immediate cessation of the ability to perform its required function.
Corrosion Fatigue
fatigue-type cracking of metal caused by repeated stresses in a corrosive environment.
FPH
feet per hour.
FMJ (control line)
ferrule metal junction.
FDP
field development plan.
FLC (operations)
field lifting cost.
FOC
field operations center.
Cake
filter or mud cake, stranded by dehydration on the face of a permeable formation by fluid loss.
Batch Treating (chemical treating)
slugging a chemical such as a biocide or a corrosion inhibitor in high concentration to accomplish either placement or super concentrated treating.
Bar Hole
small diameter hole made in the ground to obtain a sample for the purpose of searching for a gas leak in a pipeline.
Abalation Debris (perforating)
small pieces of rock broken up by the perforating process.
Ball Sealers
small, rubber-covered, hard centered balls that can seal individual perforations during a chemical treatment.
Drag Blocks
spring loaded blocks on a packer or other tool that contact the pipe wall, producing resistance to movement. They aid in setting of packers.
Finger Board (drilling)
steel fingers mounted to the derrick into which the derrick man stores pipe that is standing in the derrick.
Alkenes
straight or branched chain chemicals with some double bonds between carbons.
Alkanes
straight or branched chain hydrocarbons with single bonded carbon atoms. Describes most oils.
Back Surge
sudden backflow of a well, usually to clean the perforations.
Critical (flow)
super sonic.
Blistering (steel)
surface corrosion associated with gas adsorption.
Downhole Gauges
surface reading, downhole located gauges capable of measuring pressure, temperature and/or flow rate.
Crush Zone
the area of the rock adjacent to the perforation tunnel where permeability may be 50% less than initial, undamaged permeability.
Area-to-Volume Ratio (mineral)
the area of the surface of a grain to its physical volume.
Area of influence (of a well)
the area surrounding a well within which drawdown and production has changed the saturation and energy of the system.
Aniline Point
the aromatics content of a mixture.
Equivalent Weight
the atomic or formula weight of a material.
Adsorption
the attraction and holding of a layer of a chemical on the wall of a formation. Usually held by ionic charge or wetting preference.
Elevator Bails or Links
the bars that attach the elevators to the hook on the traveling block.
Fairway
the best part of a reservoir. Commonly used in coal pays.
Formation Competency
the breakdown (fracturing) pressure of a formation.
Carrying Capacity
the capacity of an injected or circulated fluid to transport a given sized and density solid into a zone or from a well.
Density-Depth Function (seismic)
the change in density with increasing depth is often a result of compaction. Age, lithology and porosity modification are also factors.
Acid Effect
the change in pulsed neutron capture created by acidizing a carbonate. Acidizing increases interconnected porosity and strands chlorides and other ions in the rock.
Coal gasification
the chemical conversion of coal to a gas.
Air Gap
the clearance between the highest water surface that occurs during the extreme environmental conditions and the underside of the deck.
Accuracy
the closeness of agreement between the measure value and the exact value.
Collapse Rating
the collapse pressure derated by a safety factor. Takes into account the effects of axial load. The formulas are only good for round pipe.
Assemblage
the collection of minerals that characterize a rock or facies.
Coalescence
the combination of bubbles or droplets in an emulsion to form larger bubbles or drops that will separate easier.
Covalent Bond
the combination of two of more atoms by sharing of electrons. Covalent bonds are generally stronger than other bonds.
Drilling Hook and Swivel
the components below the traveling block to which the elevators are attached.
Critical Buckling Load
the compression load that initiates buckling in the pipe.
Depositional Environment
the conditions of sediment transport and deposition at the time the formations were laid down.
Drive Pipe
the conductor pipe.
Formation Water
the connate water.
Cementing Head
the connection between the wellhead the lines from the cement trucks. A rotating head (uncommon except on top-drive rigs) allows the pipe to be rotated during the cement placement to assist in displacing mud and preventing channels.
Cable Head
the connection of the braided cable to the rope socket or attachment to the tool string in a wireline conveyed BHA.
Collar
the connection or coupling on jointed pipe. It the strict sense, it is the section with female x female connections.
Coupling
the connection point of jointed pipe. It may be a steel shell with female threads to which the pins are connected or a formed female connection (box) on the end of tubing.
Driller's Console
the control panel.
Christmas Tree
the control sections that sits above the basic wellhead. It may contain hangers, master valves, annular valves, wing valves, and gauges or pressure, flow rate or monitoring measurement equipment.
Cavitation
the creating of a high speed, very low pressure vapor bubble that quickly and violently collapses. Very detrimental to surfaces in the near proximity. Often seen in severe turbulent flow.
Daily Drilling Report
the daily report on activities, results, and shows of the past 24 hours.
Buckling
the deformation of pipe in compression as it moves from straight to sinusoidal to helical shapes in the hole. Usually in the elastic range.
Bulk Density
the density of a rock as it naturally occurs (as compared to specific density of the grains). Includes the pore structure.
Diluent
the fluid added to a concentrated mixture to reduce the concentration of an internal phase or reduce its viscosity.
Carrier Fluid
the fluid that carries proppant or other material into the well.
Frac Fluid
the fluid used in a fracturing treatment, may include pre and post treatment fluids.
Drill-In Fluid
the fluid used to drill the pay zone.
Drilling Mud
the fluid, water, oil or gas based, that is used to establish well control, transport cuttings to the surface, provides fluid loss control, lubricates the string and cools the bottom hole assembly.
Effluent
the fluids and solids, perhaps in a mixed stream, produced from a well.
Fracture Fluids
the fluids used to fracture a well. Generally, a fracture fluid is a water based fluid with less than 0.5% total additives, most of which are common in food or household use.
Fracturing Fluids
the fluids used to fracture a well. Generally, a fracture fluid is a water based fluid with less than 0.5% total additives, most of which are common in food or household use.
Drag (fluid flow)
the force on a solid surface exerted by a fluid flowing past it.
Cut
the fraction of a fluid in a mixture of fluids.
Fluid Saturation
the fractional or percent amount of pore space which a specific fluid occupies.
Base Gas
the gas required in a storage reservoir to cycle the working gas volume.
Filtration Level
the generally statement of the largest size particles in a fluid after passing through a filter.
Fracture Gradient
the gradient needed to initiate a fracture.
Fracture Network
the groupings of fractures, possibly interconnected, that form a enhanced flow unit.
Content (fuel)
the heat value per unit of fuel expressed in Btu as determined from tests of fuel samples. Examples: Btu per pound of coal, per gallon of oil, per cubic foot of gas (AGA).
Coiled Tubing Injector Head
the hydraulic powered chain driven unit that snubs or strips coiled tubing into or out of a well.
Contingent Resources
the hydrocarbons that are estimated to be potentially recoverable from known accumulations, but which are not currently considered to be commercially recoverable.
Accumulator Precharge
the initial nitrogen charge on a BOP accumulator that is placed before the fluid is pumped in to charge the accumulator.
Fracture Pad
the initial part of the fracture fluid that creates the fracture width and controls the initial fluid loss but contains no proppant.
Alpha Wave
the initial wave of gravel transport when packing a well with a deviation over 55o.
Discovery Well
the initial well in the field that tests hydrocarbons.
Bed Wrap
the innermost wrap of coil or cable on a spool or reel.
A Annulus
the inside annulus; tubing-by-production casing annulus. (Note, there may be regional differences in the A, B, C annulus designations and some are reversed. Inside annuli (IA) and outside annuli (OA) are more universally descriptive.)
Bore
the inside diameter of a tool or pipe.
Bridle (logging)
the insulated, downhole end of a logging cable.
Burst
the internal fluid pressure that will cause the onset of pipe yield.
Dispersed Phase
the internal phase in an emulsion - i.e., the droplets or bubbles.
Cathode
the negative site of a corrosion cell. Reduction reactions are typical.
Casing Weight
the nominal weight per foot of the casing. Heavier weight casings of the same size are necessarily smaller I.D.
Binder (coating)
the nonvolatile portion of a coating.
Formation Volume Factor or FVF
the number of barrels of reservoir oil that shrinks to one stock tank (surface) barrel after gas breakout and light end vaporization.
Albian
the oldest terrain from the Cretaceous period.
Company Man (drilling)
the operating company representative on location.
Depth of Investigation
the outer limit to which a logging tool can measure properties with a give accuracy.
Crust
the outermost crust of the earth.
External Phase
the outside or continuous phase of an emulsion.
Condensate
the part of the hydrocarbon stream that is a vapor in the formation and condenses to a liquid after being cooled. Normally the volatile condensate has a composition of C5 to C8 and an API gravity of >40.
Buid Section
the part of the wellbore that is changing deviation, usually building toward a maximum deviation angle.
Completion Interval
the pay zone exposed to the wellbore. This may or may not be the entire pay.
Acid Solubility
the percent by weight loss of exposing a sample of material to an excess of acid.
Absolute Porosity
the percentage of the total bulk volume that is pore spaces, voids or fractures.
Effective Permeability
the permeability of the formation matrix to a particular fluid when two or more phases are present.
Conductivity (fracture flow)
the permeability of the pack times its width. Expressed in md-ft.
Casing Crew
the personnel that specialize in handling and running casing.
Flowline
the pipe connection between the well and the separators or tank battery.
Fault Plane
the plane or direction along which fault movement has occurred.
Crown Plugs (subsea)
the plugs above the flow T in a subsea wellhead.
Buckling Point
the point in the well or the weight applied where the pipe buckles (sinusoidal bending) and stops or significantly slows during pipe running in a horizontal well.
Fracture Porosity
the porosity attributed to the natural fractures, commonly less than 2 to 4%.
Cementation Exponent
the porosity exponent, m, in the Archie Factor.
Diagenetic Porosity
the porosity formed by chemical and bacterial modification after the initial sediments were laid down.
Anode
the positively charged site in a cell. Oxidation site. The site of metal loss in corrosion.
Flowing Pressure
the pressure at some datum (usually surface, FSP, or bottom hole, FBHP, measured while the well is flowing.
Closure (fracture)
the pressure at which a fracture closes. Related to the closure forces in a formation.
Bubble Point
the pressure at which gas begins to break out of an under saturated oil and form a free gas phase in the matrix or a gas cap.
Circulating Pressure
the pressure generated by the mud pumps and, in normal circulation, exerted on the drill string.
Capillary Pressure Curve
the pressure necessary to achieve a given non-wetting fluid saturation of a rock.
Displacement (process)
the set of actions used to flow a fluid or solids out of a well and replace it with another fluid system.
Facies
the set of all characteristics of a sedimentary rock that defines its particular environment and distinguishes it from other facies.
Crown Block
the set of pulleys or sheaves at the top of the mast on a rig.
Casing Seat
the set point of the end of casing. Should be in an impermeable, stable formation.
Continental Shelf
the shallow area out from shore to a water depth of about 450'.
Foot Wall
the side of the fault that protrudes underneath the upper formation.
Fossil
the silicate replaced replica of an animal or plant.
Biophasic
the simultaneous flow of two immiscible fluids.
Decline Curve
the slope of the production rate vs. cumulative time or volume measurement. The decline of a well predicts how fast it is being depleted.
Creep
the slow movement of a solid due to an applied stress. Often very sensitive to time and rate of stress application.
Creep
the slowest form of mass movement.
Connection Gas
the small amount of gas that enters the wellbore when circulation is stopped to make a connection. The gas only enters the wellbore in this case when the static fluid pressure is less than the pore pressure.
Drill Cuttings
the small chips and fines generated by drilling through a formation with a drill bit. Most of the cuttings are removed from the mud as the fluid pass through the solids control equipment (e.g., shakers, screens, cyclones, etc.,) at the surface.
Elevators
the snap-around latches that couple around tubing below the pipe coupling and enables the traveling block on a rig to gab and lift the tubular string.
Basic Sediment and Water or BS&W
the solids and water entrained in crude oil.
Dissolved Gas (production)
the solution gas associated with produced fluids.
Delta t
the sonic travel time in microseconds per foot, of a sound wave through the formation. Denser formations (generally better consolidated and cemented) have lower (faster) delta t times.
Field Rules
the spacing and production rules in a field or unit.
Directional Driller
the specialist that plans and executes the directional drilling plan.
Cement Density
the specific gravity of the set well cement, generally about 3.15 for Portland cement. Do not confuse with slurry density.
Cement Slurry Density
the specific gravity of the unset cement slurry as mixed at the surface. Does not account for water loss to leakoff or segregation before the cement sets.
Base Fluid
the starting fluid for a pill or a treatment. Before additives.
Cement Bond
the strength and adherence of the cement to the pipe and the formation.
Final Strength
the strength of cement when the strength development with time curve ceases to change significantly.
Anvil (perforating)
the strike plate over a TCP, drop-bar firing system.
Bathymetry
the study and mapping of ocean floor topography.
Flow Path
the subsurface course that fluids would follow as they move in a reservoir or between reservoirs.
Critical Temperature
the temperature above which a fluid cannot be liquefied by increasing pressure.
Curie Point
the temperature above which a mineral loses its magnetism.
Dew point
the temperature at which liquids begin to condense from the vapor phase in a gas stream. (see also bubble point).
Crystallation Temperature
the temperature at which the first crystal of salt appears from a brine that is being cooled.
Boiling Point
the temperature at which the vapor pressure of the liquid is equal to the pressure exerted on it by the surrounding atmosphere.
Ambient Temperature
the temperature of the surroundings, usually an average surface temperature or test surface temperature.
Elasticity
the tendency of a body to return to its original shape and size once the stress is removed.
Formation Sensitivity
the tendency of a formation to react with fluids, usually filtrates from injected fluids.
Deliverability
the tested and proved ability of a well to produce.
Absolute Open Flow Potential
the theoretical maximum flow that a well could deliver with a zero backpressure at the middle of the perforations.
Depth Datum
the zero depth datum for well logging.
ECTFE
thermoplastic fluoropolymer.
Common Carrier (petroleum)
those engaged in the transport of petroleum products.
Crack a Valve
to barely open a valve.
Abandon
to cease efforts to produce or inject fluids in a wells and to plug the well sufficiently to protect the environment and the ability to redrill and develop other reserves at a later date.
Blank Off
to close in the end.
Correlate
to compare logging and core or other information and account for discrepancies.
Absorb
to fill part or all of the pore spaces.
Acid Fracture
to fracture stimulate a formation by injecting the acid over the parting pressure of the rock and using the acid to etch channels in the fracture face.
Burn Over
to mill a piece of equipment (and often to catch it with an overshot).
Blow Down
to release gas pressure. In a reservoir, blow down is often after the oil recovery phase has been complete and the majority of the gas from the gas cap needs to be recovered.
Dress Off
to remove rough edges, flares, burrs, etc. from a piece of equipment prior to fishing.
Chase
to run a pipe through a wellbore to determine if it is open.
Breaking Down (drill string)
to separate the stands into single joints.
Dress
to sharpen a bit or replace components of a tool.
Close In
to shut-in a well.
Break Tour
to start a work shift.
Buck Up
to tighten a connection.
Bleed Off
to vent or drain of fluids from a pressured well.
APR
trademarked name for an annular pressure response valve - for a DST string.
Amorphous
without crystal form.
Depreciation, Liberalized
This refers to certain approved methods of computing depreciation allowance for federal and/or state income tax purposes. These methods permit relatively larger depreciation charges during the earlier years, in contrast to the straight-line method, under which the annual charges are the same for each year. This is sometimes referred to as accelerated depreciation (From AGA).
Arenaceous
sand particles, 0.625 to 2 mm on the Udden-Wentworth scale.
Cushion Gas
the reservoir pressure necessary to keep gas recoverable.
Beta Wave (gravel packing)
the returning wave of gravel after the alpha wave when packing a well over about 55o deviation.
Drift (geological)
the rock, sand and clay moved by a glacier.
Counterbalance Weights
the rotating weights on a beam lift pump jack that offset the weight of the rod string.
Critical Saturation
the saturation of a fluid at which the fluid will begin to flow as saturation is increased.
Bottom Casing Packoff
the seal in the annulus between a hanging pipe and the next pipe outward.
Bonnet
the section of the valve housing that covers the stem and protects the seals.
Bed Load
the sediment that moves slowly along the bottom of a river channel.
Battery (fluid treating)
the separation facilities.
Dissociation
the separation of a compound or molecule into pieces, ions, or atoms.
Continental Margin
the separation of emerging continents from deep sea basins.
Chemical Treating
various chemical treatments including acidizing.
Confining Pressure
various earth forces acting on the formation. Includes overburden.
Critical Drawdown
various. Usually the sand free rate, but may also include a rate to achieve cleanup in special cases.
Acoustic Velocity
velocity of an imposed sound wave through a rock.
Broaching (flow)
venting of fluids to surface through channels in cement or behind pipe (well control barrier failure) or unintended fracturing into a adjacent formation.
Flow
very simply, movement of a fluid.
Centipoise
viscosity measurement, 1/100th of a poise.
Edge water
water at the sides or edges of the hydrocarbon deposit. Often causes problems because the channels that deplete the fastest are the highest permeability and water production through them can be severe. These respond well to treatment if they can be isolated.
Condensed Water
water condensed from gas as it is produced. Usually fresh water.
Clay-Bound Water
water held in or on the surface of a clay and not free to move with other connate fluids.
Biopolymer
water soluble polymers produced by bacterial action on carbohydrates.
Artesian Water
water that is overpressured and may rise above the formation.
Bound Water
water that is trapped in or on the matrix minerals and cannot move.
Erosion
wear of a material by a slurry of liquid and (usually) solids.
Abrasion (mechanical)
wearing away by friction.
Expandable Casing
well construction tubulars run in like conventional casing but mechanically enlarged downhole before the cement is set.
Conformation Well
well or wells drilled to prove the formation or resources discovered in the initial or discovery well.
Expandable Completions
wellbore tubulars run in like conventional completions but mechanically enlarged downhole once in place. Can include combinations of sand screens, blank pipe and annular isolation seals used in lieu of gravel packs.
Development Well
wells that are drilled after the discovery and appraisal wells to develop the hydrocarbon production potential of the field.
Flow Profile
what the flow looks like across the cross-section of the pipe.
Decompression Damage (gas effects on seals)
when pressure is dropped rapidly, gas that has permeated the elastomers and some plastics may rupture the surface of a material when the gas expansion caused by the decompression is faster than the gas can pass through the substance. Most severe in weak tensile-strength materials.
Failure
when the designed function can not longer be met.
Collision
when the drill bit in a new-drill well contacts an existing wellbore.
Disaggregation
when the formation breaks into grains.
Economic Limit
when the revenue from the produced fluids falls below the cost of operations set by the company.
Coiled Tubing Drilling
where CT is used as the primary drill string with a mud (less commonly an electric) motor to rotate the bit. Often used in underbalanced drilling.
Diagenetic Trap
where rock changes produces a reservoir rock under a sealing rock.
Fault
where rock splits or ruptures with associated movement occurs on either side.
EIA
Energy Information Administration.
Dissolved Gas
Oil Ratio: the amount of gas contained in the oil (in std ft3/bbl). This value can change if one fluid is produced faster than the other or if one fluid is re-injected.
Associated Reservoir
Oil and gas reservoir with a gas cap. Gas production from these reservoirs may be restricted in order to preserve the gas cap energy and ultimate recovery.
Barrier (NORSOK definition)
One of several dependent barrier elements, which are designed to prevent unintentional flow of a formation fluid. A barrier is an envelope preventing hydrocarbons from flowing unintentionally from the formation, into another formation or, to surface. Barrier elements that make up the Primary barrier are those elements, which are or might be in direct contact with well pressure during normal operation. These elements provide the initial and inner envelope preventing unintentional flow of reservoir fluid to surface, or another zone. Barrier elements that make up the secondary barrier are those, which are or might be exposed to contact with well pressure should any of the elements described as a Primary barrier fail. These elements provide an envelope outside the Primary barrier envelope providing a second barrier preventing unintentional flow of reservoir fluid to surface, or another zone.
Cement Channel
a channel in the cement, usually caused by poor displacement of drilling mud.
Breaker
a chemical added to a gel that breaks down the gellant structure.
Casing Gun
a large perforating gun, run into a well without tubing.
Displacement Efficiency
a measurement of how completely a flooding fluid displaces the saturated fluid in a reservoir.
Darcy
a measurement of permeability (ability of fluids to flow through the rock). The relationship is an empirical law which states that the velocity of flow through porous media is directly proportional to the hydraulic gradient, assuming that the flow is laminar and inertia can be neglected.
Formation Resistivity
a measurement of the electrical resistivity of a formation. The measurement will be significantly affected by the type of fluid and the salinity of water based fluids within the pores of the rock.
Directional Survey
a measurement of the well path that records the inclination and azimuth of the wellbore using a compass or other device.
Fracture Fluid Efficiency
a measurement, derived from a data frac, of the efficiency of a particular fluid in creating fracture area on a particular formation at a set of conditions.
Collett
a mechanical device used for holding or locking where segmented keys or fingers are pushed into a recess to hold, anchor or grasp the tool.
Coiled Tubing Connector
a mechanical device used to join strings of CT or attach a BHA to the CT.
Decentralizing Arm
a mechanical level that pushes a tool against the side of the well.
Casing Cutter
a mechanical, chemical or explosive device that cuts the casing at a specific point.
External Cutter
a mechanical, chemical or explosive device that is lowered over a pipe to cut from the outside.
Fatigue
a metal failure based on weakening by flexing or cycling. The material often work hardens.
BX Ring
a metal-to-metal seal for a flange.
Allocation Method
a method of allocating volumes to affected parties when an imbalance occurs.
Flash Set
a rapid, usually unplanned, thickening of cement.
Endothermic
a reaction that absorbs heat.
Acid
a reactive material with a low pH. Common oilfield mineral acids are HCl and HCl/HF.
API RP
a recommended practice published by the API.
Cap Rock
a sealing formation of very low permeability that forms the top or the seal in a reservoir.
Antitheic Fault
a secondary fault, often in a set, with an opposite direction to the primary fault.
Anithic Fault
a secondary fault, often in a set, with opposite direction to the primary fault.
Bypass (piping)
a secondary flow path that goes around a repair point or other feature.
Babbitt
a soft metal alloy used in some seals and bearings.
Dummy Valve
a solid body (non flowable) gas lift valve that "dummies off" a gas lift mandrel to seal the GLM or pocket.
Boll Weevil (various)
a solid hanger or test cup in a BOP. A retrieval plug attached to drill pipe. An inexperienced worker.
Acid Stick
a solid stick of chloro-acetic or sulfamic acid for small scale removal of acid soluble deposits.
Borehole Televiewer
a sonic caliper, developed in the late 1960's, which generated a sonar picture of the wellbore.
Cement Bond Log
a sonic log that determines the top of the cement column and estimates the quality of the cement bond between the casing and the formation. Works on transmission of a sound wave and identifies areas that conduct the wave and those that do not (free pipe ringing). Communication is likely if CBL>10% of unbonded mv reading. Communication is unlikely is CBL < 5% of unbonded mv reading and bond length > 10 ft (3 m).
Acoustic Logging
a sonic travel time record of a formation using a tool with an emitter and a detector. Measures porosity and is useful to compare to other porosity longs to estimate pore filling. Also used to generate rock strength evaluations.
D40/D90
a sorting criteria useful in screen selection.
Bholin
a specialized viscosimeter.
Bright Spot
a specific seismic reflection that may indicate gas.
DV Tool (cementing)
a stage tool.
API Monogram
a stamp indicating that the item is manufactured to API specifications.
API Fluid Loss
a standard fluid leakoff test published by API.
F Nipple
a standard profile. Can accept a plug or other tools.
Austenitic Steel
a steel with a microstructure consisting of austentite at room temperature.
Ball (tool operation)
a steel, aluminum, brass or plastic ball pumped or dropped downhole to shift or operate a tool.
Arryo
a steep sided gulley in arid areas that carries runoff, usually at high velocities, for very short times after a rain.
Fast Taper
a steep slope.
Borax Logging
a test technique using an injected solution of borax and a detection tool to spot channels.
Biot
a theory of acoustic propagation in porous and elastic media that taken into account fluid behaviors.
Acid Inhibitor
acid corrosion inhibitor. Slows the acid attack on metal.
ACFM
actual cubic feet per minute.
Deviation Angle
actual term is inclination - the angle from vertical in a section of a well.
Fluidize
add sufficient fluid in an unconsolidated sand matrix to break cohesive bonds and lubricate grain by grain movement of sands.
Belt Effect
added friction in a deviated well as wireline or coil rubs against the top of the deviated section as the tube or cable is pulled out of a well.
Appraisal Well
additional wells drilled after a discovery, to confirm the size of a hydrocarbon deposit. Normally used to run buildup tests, drill stem tests, top and bottom of formation, gather core or fluid samples or other evaluations.
ATP
advanced technology parts.
AAR
after action review.
ACA
after closure analysis; a fracture performance test method.
Buy Back Agreement
agreement between a host and a contract lease holder under which the host pays the contractor an agreed price for all or part of the produced hydrocarbons.
Dry Tree Well
an offshore well with the wellhead and access to the well at the surface.
Chalk
an often highly porous but lower permeability carbonate composed of fine grained marine sediments such a coccoliths.
Blind Pool
an oil and gas partnership that has not committed to a specified project at the time of amassing capital.
Drying Oil
an oil capable of conversion from a liquid to a solid in the presence of air.
Barrel
an oilfield measurement barrel is 42 US gallons or 5.615 ft3 or 6.28 barrels = 1 meters3. Note that reservoir barrels undergo shrinkage by the reservoir volume factor as gas escapes. Stock tank barrels are measured after gas escapes.
Braden Head
an older (actually trademarked name) for the wellhead.
Formaldehyde
an older biocide, now rarely used.
Bullet Gun
an older perforating method where hardened steel bullets were fired from short barrels and designed to penetrate the casing, cement and formation.
Farmer's Oil
an older term indicating the mineral owners royalty-based "share" of the oil. This was from a time when natural gas had no value.
Back-Haul
an operation or transaction that results in movement of gas in a direction opposite of the normal flow direction in a pipeline.
Formic Acid
an organic acid used in higher temperature wells for shallow damage removal.
C Annulus
an outside annulus, next out from the B annulus, usually production casing x production casing or surface casing. (Note, there may be regional differences in the A, B, C annulus designations)
B Annulus
an outside annulus, one out from the A annulus, usually production casing x production casing or surface casing. (Note, there may be regional differences in the A, B, C annulus designations)
Farm-In
an outside party paying a concession owner all or a percentage of the drilling costs of a well in order to obtain a working interest in the land or well.
Cherry Picker (fishing)
an overshot fishing tool with a bottom cutter surface to allow milling the top slips or all the slips prior to retrieving a packer.
Blowout
an uncontrolled release of fluids from a well.
Blank
an unperforated piece of casing or tubing in an otherwise perforated section. Used for isolation.
Assay
analyze.
AHV (subsea)
anchor handling vessel.
AAIOR
annualized average incremental oil rate.
AAV (subsea)
annular access valve.
AFV
annular flow valve.
AFE (well operation)
annular fluid expansion.
AFP
annular friction pressure.
AIS
annular isolation sleeve.
APB
annular pressure build up.
APRV
annular pressure relief valve.
APR
annular pressure relief valve. Used in reverse circulating to prevent pipe collapse.
ACV
annular safety valve.
ASV
annular safety valve.
AV (flow)
annular velocity.
AWV
annulus wing valve.
Cyclonite
another name for RDX explosive.
Box Tap
another name for a tapered tap. Used to screw into boxed of connections.
Antifouling
any action designed to reduce or prevent fouling (deposits) on a surface.
Degasser
any device that helps remove gas from circulated fluid.
Formation
any distinct, mapable layer.
Bonus Money (contract)
any funds paid to a mineral owner in addition to least of royalties.
Downhole Camera
any of a variety of downhole cameras, including full motion video, recording memory camera, sequence sending cameras, etc. Used to get a better picture of the wellbore or a fish.
Chat
any of many types of conglomerates.
Cased Hole Log
any of several radioactive, chemical or physical properties logs that are run in a cased hole environment. May be conveyed by electric line, coiled tubing, slick line (memory logs) or drill pipe (LWD).
Casing Patch
any of several repair systems designed to set a patch over a leak in a well.
Ball Valve
any of several valves that rotate a ball with a flow passage to allow or deny flow.
Carbonate
any of the many rocks composed of calcium carbonate (limestone) or magnesium carbonate (dolomite) or other acid soluble rocks with a common CO3-2 ionic charge. The pores may be poorly connected and matrix permeability (non fractures) are often much lower than sandstones.
Concentric Operations
any operation where a smaller tubing is inserted through a larger tubing string. Normally done with the wellhead in place. Often done with the well under pressure.
Biomass
any organic material.
Flow Wetted
any piece of a tool or the well that is wetted by the produced fluid flow.
Body
any portion of the wellhead or tree that contains wellbore pressure.
Fines Control
any process designed to minimize movement of otherwise mobile fines, typical size < 44 microns.
Acid Gas
any produced gas, primarily H2S and CO2 that form an acid when produced in water.
Dispersant
any substance that aids in breaking up a mass of individual particles, bubbles or droplets.
AV (fluids)
apparent viscosity.
Bulk Modulus (K)
applied stress over change in volume.
APD
approved permit to drill.
APE
area petroleum engineer.
AL
artificial lift.
ALARA
as low as reasonably achievable.
Fly Ash
ash from the burning of coal. Used as an extender in several cements and as a plug component.
Asph
asphaltene.
AD
assistant driller.
Aggregation
attraction and adherence of clumps of small particles.
Flocculation
attraction, gellation and drop out of suspended particles from a liquid.
Adhesion
attractive forces between unlike molecules or compounds. Example - the attractive forces between water molecules and the walls of a clean glass tube are stronger than the cohesive forces; this leads to an upward turned contact or meniscus at the wall.
AFD
authorization for definition.
APE
authorization for expenditure.
AOR
authorized over-run.
AUV (subsea)
autonomous underwater vehicle.
Drilling Efficiency
average distance drilled per day divided by the total number of days in a measurement cycle.
CHKS
back flow checks.
BPV
back pressure valve.
BHCS
bottom hole compensated sonic.
BHFP
bottom hole flowing pressure.
BHFT
bottom hole flowing temperature.
BHG
bottom hole gauge.
BHIP
bottom hole injection pressure.
BHL
bottom hole location.
BHP
bottom hole pressure.
BHS
bottom hole sample.
BHS
bottom hole seismic.
BHSIP
bottom hole shut-in pressure.
BHST
bottom hole static temperature.
BHTV
bottom hole televiewer - a sonic caliper tool, not a television.
BHT
bottom hole temperature.
BHTP
bottom hole treating pressure.
BH (well position)
bottom hole.
BTMS
bottoms.
BLM (wireline)
braided line measurement
BHp
brake horsepower.
Biodegration
breakdown of a heavier oil to a lighter hydrocarbon by bacterial action.
Encapsulated breaker
breaker in small pill-form particles that stays with the polymer and helps break the mud cake.
DPC (gas lift)
casing pressure at depth - the true gas weight at depth.
Csg
casing.
CIBP
cast iron bridge plug.
CFPP
cold filter plugging point.
CHOPS
cold heavy oil production with sand.
Cratering or Sloughing
collapse of part of the formation into the wellbore during drilling or completions.
CFE
core flow efficiency.
ES (treating)
electrostatic separator.
EL
elevation.
EDP (subsea)
emergency disconnect package.
ESDS
emergency shut down system
ESV
emergency shut-down valve.
ESD
emergency shut-down.
Fast Line (drilling)
end of a braided drilling line affixed to the draw works.
EOB
end of build (horizontal wellbore).
EOC
end of curve.
EOT
end of tubing.
EOWR
end of well report.
Convective Mixing
mixing created by heat transfer.
Class G and H Cements
oilfield related cements.
Active
A corrosion state where a metal is corroding without control by a reaction product (or corrosion product layer).
Bull Wheel
old term for a large, often wooden wheel, in a cable tool rig.
Acre-Ft
one acre (43560 ft2) to a depth of one ft.
Air Density
0.763 lb/ft3 at standard temperature and pressure.
Demonstrated Reserves
(American Petroleum Institute) A collective term for the sum of proved and indicated reserves. Proved reserves are estimated with reasonable certainty to be recovered under current economic conditions. Indicated reserves are economic reserves in known productive reservoirs in existing fields expected to respond to improved recovery techniques where (1) an improved technique has been installed but its effect cannot yet be fully evaluated, or (2) an improved technique has not been installed but knowledge of reservoir characteristics and the results of a known technique installed in a similar situation are available for use in the estimating procedure.
Arrest Marks
(failure/crack development): characteristic markings (ridges, tears, risers, etc.) on fracture surfaces after fatigue crack of fracture propagation (also known as beach marks, clamshell marks, and conchoidal marks).
Deconvolution (seismic)
(using Werner) an automated profile-based depth estimation method derived from analysis of magnetic anomalies in sheet-like bodies. Polynomials can be simultaneously solved to estimate the depth, dip, horizontal location and susceptibility (magnetic) of the surface or structure. Basically undoing the effects of a filter.
Angstrom
10-10 meter.
Barite Plug
: a settled plug made of particles or barite or even barite and sand that are placed to seal off a zone or the wellbore.
Balanced Plug
A cement plug, set with no downhole flow conditions, which allows temporary or permanent shut-off in a well. It takes into account the densities of all fluid columns, both in the string and in the annulus.
Accelerator (chemical)
A chemical that speeds up the rate of a chemical reaction. Most common are the accelerators used in cementing.
Concession (lease)
A grant of access for a defined area and time period that transfers certain rights to hydrocarbons that may be discovered from the host country to an enterprise. The enterprise is generally responsible for exploration, development, production and sale of hydrocarbons that may be discovered. Typically granted under a legislated fiscal system where the host country collects taxes, fees and sometimes royalty on profits earned (SPE).
Collar Log
A magnetic inflection log, run on wireline that is principally used to locate the depth of threaded pipe connections and other masses of metal.
Depreciation, Straight Line
A method of computing depreciation under which equal annual amounts are set aside for the ultimate retirement of the property at the end of its service life. For a property with an assumed 25-year life, the annual charge would be 4% per year, usually applied to the cost of the property less estimated net salvage (From AGA).
Depreciation, Units of Production
A method of depreciation whereby the asset is depreciated over an estimated life expressed in units of output rather than over an estimated life expressed as a period of time (From AGA).
Confining Bed
A rock layer that through either low permeability or different modulus serves as a boundary for an event such as fluid flow or fracturing.
Arkose
A sandstone containing 25% or more of feldspar, usually derived from igneous rock.
Depreciation, Asset Depreciation Range
A system of tax depreciation which enables a corporation to choose any life falling within 20% of the designated class life for determining its annual depreciation charge. ADR requires an annual election and all depreciation records must be maintained by vintage year (From AGA).
BW Rod Thread
A thread for tools and equipment that has three parallel threads per inch (similar to a AW thread). Used in applications greater than 1.75" OD.
AW Rod Thread
A thread for tools and equipment that has three parallel threads per inch (similar to a BW thread). Used in applications of 1.75" OD thread or less.
CONCAWE
Conservation of Clean Air and Water in Europe.
Abandonment Cost
Costs associated with the abandonment of facilities or services, including costs for the removal of facilities and restoration of the land.
DRBA
Delaware River Basin Authority.
D.O.T. (government)
Department of Transportation - a US government agency.
DnV
Det Norske Veritas: a classification and qualification setting business.
Developed Reserves (reservoir)
Developed reserves are expected to be recovered from existing wells including reserves behind pipe. Improved recovery reserves are considered developed only after the necessary equipment has been installed, or when the costs to do so are relatively minor. Developed reserves may be sub-categorized as producing or non-producing (SPE).
DHVTM
Down Hole Video, Inc.
DST
Drill Stem Test.
DIMS
Drilling Information Management System.
Dry Gas (reserves)
Dry Gas is a natural gas containing insufficient quantities of hydrocarbons heavier than methane to allow their commercial extraction or to require their removal in order to render the gas suitable for fuel use. (Also called Lean Gas) (SPE).
EGM
Electronic Gas Measurements.
EPCRA
Emergency Planning and Community Right-to-Know Act.
Archie Correlation
Empirical relationships between the formatu=ion resistivity factor, the porosity, water saturation and the restivity of the fluid in the pore in clean, granular rock.
Annular Injection
Injection of fluids down the annulus or "backside". Common as a gas supply path for gas lift. Also used in some fracturing operations, to spot fluids downhole when no packer is used or a type of injection valve is in the tubing to allow entry of chemicals, gas or water.
Amorphous Kerogen
Kerogen that lacks distinct form or shape under microscopic exam. May describe oil prone Kerogen.
Discontinuous Lenticular Sands
Limited aerial sands.
Flocculants
Materials used to increase visicosity. They cause colloidal particles to group into bunches or flocs.
Capacitance Tool
Measures the fluids capacitance - uses the wellbore fluid as the fluid between plates of a capacitor.
Depreciation, Declining Balance
One of the liberalized methods of computing depreciation (normally used for tax purposes). Under this method, the depreciation rate is stated as a fixed percentage per year and the annual charge is derived by applying the rate to the net plant balance, which is determined by subtracting the accumulated depreciation reserve (From AGA).
Depreciation, Sum of the Years
One of the liberalized methods of computing depreciation, normally used for tax purposes. Under this method, the annual deduction is derived by multiplying the cost of the property less estimated net salvage, by the estimated number of years of service life remaining, and dividing the resultant product by the sum of all the digits would be 25+24+23+22+ etc. +5+4+3+2+1 or 325. A simple way to compute this figure would be to multiply the number of years by the number of years plus one and divide by 2, i.e., (25 X 26) : 2 = 325. The first year's full depreciation deduction would be 25/325ths; the second year's would be 24/325ths, etc., of the cost of the property (From AGA).
Barite
One of the many forms of the barium sulfate mineral. The BaSO4 material is used in drilling mud as a weighting agent and can produce a slurry of over 20 lb/gal in water.
FFKM
Perfluoroelastomers (KalrezTM, ChemrazTM, etc.).
BR
Petrobras.
Entitlement (reserves/production)
Reserves consistent with the cost recovery plus profit hydrocarbons that are recoverable under the terms of the contract or lease are typically reported by the upstream contractor (SPE).
Bioturbation
Reworking of the sediment by burrowing animals.
Calcium Reducers
Soda ash, bicarbonate of soda, caustic soda and some phosphates. Act to reduce the effects of calcium in a fluid.
Air
Standard density of dry air, free of CO2 at 0oC is 1.292 g/L.
Balance Point (coiled tubing or snubbing)
Static condition of the length of tubing in the well, where buoyed tube weight (well fluid sensitive) equals the well pressure acting against the cross-sectional area of the tube. The balance point does not include any frictional forces exerted by friction with the well or the stripper assembly.
Discovered Petroleum Initially in Place
That quantity of petroleum which is estimated, on a given date, to be contained in known accumulations, plus those quantities already produced therefrom. Discovered Petroleum-initially-in-place may be subdivided into Commercial and Sub-commercial categories, with the estimated potentially recoverable portion being classified as Reserves and Contingent Resources respectively (SPE).
CVP
The Group Capital Value Process, essentially the application of the stage gate decision process.
Annulus
The area between the O.D. of an inside string and the ID of an outside string.
Derrick
The elevated section of a rig that rises above the substructure and houses the crown block and draw works.
Equivalent Mud Weight
The equivalent mud weight felt by the formation when circulating with a certain mud weight and holding a backpressure. A 10 lb/gal mud in a 10,000 ft well with 1000 psi backpressure would generate an equivalent mud weight of about 11.9 lb/gal.
Base Pipe
The inside pipe of a sand screen or other equipment on which other equipment or parts are added.
Fluid Density
The mass per volume density of a fluid.
Bottom Hole Pressure or BHP
The pressure at the bottom of the well. In a producing well the BHP may be the bottom hole flowing pressure or the bottom hole shut-in pressure. In a drilling or workover environment, the BHP is exerted by the column of fluid in the hole.
Blind Rams
The ram sections in a BOP that are used to close against each other and isolate the well when no pipe is in the well.
Discovered (reserves)
The term applied to a petroleum accumulation/reservoir whose existence has been determined by its actual penetration by a well, which has also clearly demonstrated the existence of moveable petroleum by flow to the surface or at least some recovery of a sample of petroleum. Log and/or core data may suffice for proof of existence of moveable petroleum if an analogous reservoir is available for comparison. (See also "Known Accumulation": Petroleum quantities that are discovered are in "known accumulations" or "known reservoirs") (SPE).
Density Log
one of a number of logging techniques that estimate the density of the formation.
Casing Seat Test
a LOT or an FIT test (check specifics for details), a pressurized test after primary cementing to make sure the bottom most seal with the formation will handle pressures needed for drilling the rest of the well.
Flush Joint
a Non Upset connection in most cases.
Brent
a North Sea field with a light crude oil used for cost comparisons.
Compressional Wave
a P wave.
Cell Spar
a Spar platform with multiple floatation sections. Cellar: a concrete or culvert pipe walled section below ground that often protects and shelters the annular access valves. Also used to house the BOP's on a drilling well.
Bbl
a Standard Oil measure of 42 gallons, originally known as a blue barrel and abbreviated bbl. 0.16 m3.
CERCLA
a US Law - Comprehensive Environmental Response, Compensation and Liability Act of 1980.
Chevron Pattern (corrosion)
a V-shaped pattern on a fatigue or brittle-fracture surface. The pattern may also be one of straight radial lines on round specimens.
Chevron packing (seal)
a V-shaped seal very common on moving and static seals.
Backbite
a backlash of tongs that results in a grip in the wrong direction.
Drop Bar (perforating)
a bar dropped from surface to set off a TCP gun in a near vertical well.
Core Barrel
a barrel in the drilling BHA with a coring head designed to receive a rock core cut as part of core sampling operations.
Fold
a bend-like disruption in a rock strata such that the angle of the formation is significantly changed.
Bi-Center Bit
a bit that, when rotated, drills a hole larger than its diameter.
Centralizer
a bladed or bow spring tool that helps center tools or pipe in the wellbore.
Detonator
a blasting cap.
Bridge
a blockage in the wellbore caused by a mass of particles that lock together and prevent pipe movement or flow.
ClampOnTM Sand Detector
a brand name of a sand particle movement detector.
Coating Holiday
a break in an otherwise continuous coating.
Composite Bridge Plug
a bridge plug made mainly of plastic and composite materials.
Compatible Brine
a brine that does not create formation damage or permeability reduction when introduced into a formation.
Clear Brine
a brine without suspended solids.
Completion Fluid
a brine, oil or gas based fluid that is used as isolation (kill, separation, inhibition functions, etc.) fluid during the completion of a well. Commonly sea water, NaCl brine, formation water, KCl brine, CaCl2 brine, etc. Oil based fluids are common where formation sensitivities with shales, clays, minerals, etc., prevent use of aqueous fluids.
Bed Filtration
a build-up of particles on the upstream side of a filter that improves the filter's ability to remove particles from fluid (will also raise the differential pressure across the filter).
Flare
a burner on a remote line used for disposal of hydrocarbons during clean-up, emergency shut downs and for disposal of small volume waste streams of mixed gasses that cannot easily or safely be separated.
Butadiene
a butane derivative used in manufacture of synthetic rubber (elastomers).
Calcareous Coating
a calcium carbonate coating.
Caliche
a calcium rich surface soil.
Free Point Constant
a calculation used in the stuck pipe calculation to correct for pipe wall thickness and diameter.
Chlorine Log
a cased hole log, using gamma ray capture by chlorine atoms, that helps estimate the salinity or water behind pipe.
Foam Cement
a cement slurry, foamed with between 40 and 60% nitrogen gas. Has a slurry density of about 7.5 to 10 lb/gal (0.9 to 1.2 g/cc).
Block Squeeze
a cement squeeze into a area of perforations. Often done initially over the frac pressure.
Disconformity
a change in the formation that may have been caused by ancient erosional forces. Accounts for variances in formation tops in near-by offset wells in a formation with no pay inclination.
Emulsion Stabilizer
a chemical or physical effect that prevents separation of two or more, normally immiscible phases. Normally surfactant, electrical charge, liquid or emulsion viscosity, or micron sized solids at the interface.
Biocide
a chemical or treatment that bills bacteria.
Beneficiation
a chemical process that changes the state of a clay or other mineral to make it meet specific performance levels.
Corrosion Inhibitor
a chemical substance or combination of substances that, when present in the environment, prevents or reduces corrosion (NACE).
Curing Agent
a chemical substance used to initiate the hardening reaction of a resin.
Chelant
a chemical that can tie up the molecules of an element, such as iron, and keep it in solution past the point where it should naturally precipitate.
Catalyst
a chemical that enables or speeds up a chemical reaction without being consumed by the reaction.
Buffer
a chemical used to keep the pH in a certain range without extremes of high or low pH.
Activator
a chemical, heat, radiation, or mechanical action that starts or accelerates a chemical reaction.
Chlorinated Hydrocarbons
a chlorine atom substituted onto an alkane (hydrocarbon chain). These materials have been identified as refinery catalyst poisons.
External Cage Choke
a choke capable of handling high solids content flow. The external sleeve is moved over a perforated hub with high erosion resistance properties.
Expandables
a class of pipe that can be expanded for cladding corroded or worn casing, saving room in a completion, casing open hole, sealing off perforations, etc.
Authigenic
a clay or other mineral that was formed within the pore spaces of the rock. The material is most often formed by reaction or precipitation from connate fluids.
Chlorite
a clay type marked by high iron content. Usually not water sensitive and only slowly acid soluble. Very occasionally existing as fragile, free standing rims following sand grain dissolution over geologic time.
Bayrite
a clay-based drilling mud gelling agent.
Barrier Coating (protective)
a coating applied over a surface to prevent handling damage.
Barrier Coating (corrosion)
a coating with a high resistance to permeation of liquids/gasses.
Attapulgite Clay
a colloidal, viscosity building clay used in water based muds. They generate viscosity due to the mechanical interference of their straw shaped bodies.
Carbon Dioxide
a colorless gas. Corrosive when occurring with water. An acid gas. The most common cause of corrosion in the oil industry.
Expandable Hanger
a combination hanger and packer run like conventional hangers for drilling liners and well completions but permanently mechanically expanded once in the well.
Benzoic Acid Flakes
a common diverter. It can sublime, or go directly from a solid to a gas.
Differential Sticking
a common method of pipe sticking where the overbalance pressure in the wellbore pushes the tubing against the side of the wellbore in a permeable formation.
Fann Viscometer
a common viscometer for oil-field fluids.
Common Process
a common way of working that generates and/or protects value, sets out baseline expectations, to materially impact performance, is enduring and globally consistent, and helps advance the capacity of the global organization.
Clintoptolite
a common zeolite mineral with sensitivity to some surfactants.
Flange
a common, high pressure wellhead connection, using bolt attached flange plates and metal-to-metal seals.
Analogous Reservoir
a comparable reservoir with many similar characteristics (e.g., lithology, depositional environment, porosity, perm, drive mechanism, produced fluids, etc.) that can be used for behavior projections comparison studies.
Cased and Perforated
a completion technique where casing is cemented in the drilled hole and perforations are placed at the most promising flow points based on log interpretations.
Cavity Completion
a completion that uses flow to purposely increase the size of the open hole wellbore.
Coiled Tubing Completion
a completion where CT and associated CT-mounted hardware is used as the primary completion flow path.
Capillary Action
a complex force governing some fluid movements, especially in smaller pores. Capillary action is the result of adhesion and surface tension forces. Adhesion (or attraction) by a fluid to the walls of a pore creates an attracting (or repelling) force, which along with surface tension and cohesion, keep the fluid together. Thus in a capillary or small pore, the level of the fluid may be above or below the surrounding level in larger pores. This helps explain water blocks.
Ancillary Component
a component (e.g., bend stiffeners and buoyancy modules) used to control flexible pipe behavior.
Bicarbonate
a compound containing the HCOO- ion.
Additive
a compound incorporated into a gas, liquid, or solid system to alter the properties for a particular purpose.
Farm-Out
a concession owner selling a percentage of a lease to an outside operator for drilling a well.
Fracture Propagation Pressure
same as fracture extension pressure.
Beta Rating (filtration)
a conditional ratio requirement on a filtering system that compares the number of particles of a certain size in the unfiltered and filtered fluid. A beta rating of 1000 at 5 microns means that there is one particle of 5 micron or greater size in the filtered fluid for every 1000 particles of 5 micron or greater size in the unfiltered fluid.
Blowout Preventer or BOP
a conditional surface pressure barrier often consisting of a set of hydraulically operated rams containing equipment designed to grip pipe, seal around pipe, shear off pipe or seal an open hole during drilling or a workover. It may also contain an annular preventer.
Dimple Connector (coiled tubing)
a connector with shallow holes into the body and threads on the other for attaching a BHA to coiled tubing. The end with shallow holes is slipped into the coiled tubing and a clamp-on device with set screws is used to deform the coiled tubing wall into the dimple.
Coiled Tubing
a continuous reeled tube from 1" diameter to >3.5" diameter. The tubing is injected into a well via a coiled tubing unit (CTU) and can be used to unload wells with liquid, foams or gasses, logging, fracturing, etc.
Casing String
a continuous string of casing, usually cemented over at least part of its length and usually extending back to surface from the set point.
Drillstem Test or DST
a controlled production of a small amount of fluid from an isolated section of the pay zone into the chamber formed by the drill pipe and a downhole valve. DST's measure pressures, some elements of depletion and gather samples of the produced fluids.
Crude Oil Equivalent
a conversion of all gas forms to a comparison oil volume. Conversion factors are usually 5.6 to 6.0 mscf (depending on btu of the gas) to 1 bbl of oil.
Anticline
a convex-upward formation of rock layers (a fold with the strata sloping down on the sides from a common crest. In association with a sealing rock, an anticline may form a trap for hydrocarbons. Anticlines may be faulted or unfaulted. The majority of the hydrocarbons produced so far have been from anticlines.
AMPS
a copolymer. Acrylamido-methyl-propane sulfonate polymer.
Beta Factor (flow)
a correction factor for the Darcy Equation to account for changes in pressure and fluid saturation along a fracture.
Duplex Steel
a corrosion resistant alloy with chrome and nickel as common components.
Female connection
a coupling with threads on the inside.
Barchan
a crescent-shaped sand dune with a convex face upwind and a concave face downwind.
Dog House
a crew or records shack at a lease or on a rig.
Borate
a crosslinker for guar based gels.
Compaction
a crushing of the matrix structure as overburden loads press down on the rock, reducing the pore space. During production of the well, the load on the matrix increases as the pore-filling fluids are removed. These loads may reduce the porosity of the rock expelling fluids from the rocks (compaction recovery of fluids). Permeability may be decreased in compaction, first by closing natural (unpropped fractures) and then by reduction of matrix perm in severe cases.
Chalcedony
a cryptocrystalline form of quartz with waxy luster.
Contour
a curve connecting points of equal value on a map.
Differential SP
a curve recorded as a simultaneous SP measurements from two electrodes, each serving as a reference potential for the other.
Ball Catcher
a cylinder at surface to catch ball sealers before the fluid is routed through the choke.
DP (perforating)
a deep penetrating charge.
Downhole Shutoff
a deliberate shut off of a zone by a downhole valve or other method, to prevent cross flow.
Baume (density)
a density scale used in mineral acid strength measurement.
Dune
a deposit of sand produced by wind or running water. The dune may be massive, but usually lower energy and permeability varies.
Braided Stream
a depositional environment with several channels that may or may not be connected.
Crater (blow out)
a depression formed from a release of gas through loose soil at the surface or sea floor.
Extrusive Igneous Rock
a description of rock resulting from a magma breach to surface and exposed to atmospheric conditions during cooling.
Booster Cap
a detonating cap between two detonating cords in a series of perforating guns.
Cementing Head
a device attached to the top of the casing that allows connection of the flush and cement lines and allows plugs to be dropped. Special models may allow the cement to be rotated during cementing.
Expansion Joint
a device in a length of pipe that allows some pipe length expansion or contraction.
Bottom Shot Detector
a device in a perforating gun that signals through a delayed shot or sound that the detonating cord has fired to the bottom of a gun.
Diverter (wellhead)
a device in the flowpath at the wellhead that forces fluid to go down a pipe to a pit or tank.
Dampner or Dampener (flow line)
a device in the line filled with gas that may reduce the surges of pressure pulsation or flow slugging.
Annular Preventer
a elastomer bag or donut type seal, pushed into contact with the pipe or tools in the blow out preventer (BOP). It is designed to seal around pipe or any other irregular surface tool (packers, guns, pumps, etc.) that may be in the BOP. May also be called a Hydril preventer.
Emulsifier
a emulsion stabilizing mechanism, usually either surface active agent, fines, viscosity and/or charge.
Carbide Blast Joint
a erosion resistant covering or main pipe that is used when tubing is set deeper than the perforations or on the long string across from the upper perforations in a side-by-side completion.
Extraction Plant
a facility for removal of liquids from gas.
Abject Failure (Risk)
a failure mode that can cause the cancellation-of or immediate-halt-to a project or event. Generally expressed as a percent probability.
Embrittlement
a fatigue state of metal that may be caused by trapping atomic hydrogen in the structure of the steel. Characterized by loss of ductility. May also be caused by work hardening or other factor.
Dutchman
a filler piece used to close a gap in piping or equipment alignment.
Absolute Filter Level
a filter rating that purports to set the maximum size of an opening in a filter or the maximum size of the particle that can pass through the filter. The definition varies with use and company.
Cartridge Filter
a filtering device that uses replaceable cartridge elements to filter liquids to a required level.
Clay
a fine grain (<0.00015" or about 4 microns) - finely crystalline silica sheet minerals. Usually of silicate composition. In oil field terms, the most common clays are Smectite (montmorillinite), illite, kaolinite and chlorite. The characteristic for authogenic clay is to have extremely high surface area-to-volume ratio.
Fissile (rock)
a fissile rock tends to break along a plane or planes that are roughly parallel to the bedding planes.
Blind Flange
a flange plate without an opening, normally used as seal-off assurance over an unused line.
Blind Box
a flat bottom, short steel tool run on wireline to tag the surface of water or solids in the well. It is nearly the drift diameter of the tubular.
Breakthrough
a flood front breaking through into a producing well.
Channel (cement)
a flow area in the cement from inefficient cementing displacement of the drilling mud.
Downhole Choke
a flow bean (restriction) set in a profile near the bottom of the well. Used as a flow regulator and to take part of the pressure drop downhole to reduce the potential of hydrates.
Back Pressure Valve
a flow control valve that provides some control when running or pulling a string.
Churn Flow
a flow regime in which the rising gas bubbles have enlarged.
Bean
a flow restriction common in downhole chokes, surface chokes and some SSSVs.
Flow Bean
a flow restriction common in downhole chokes, surface chokes and some SSSVs.
Flow Test
a flow test designed to prove that hydrocarbon exists in the reservoir and will flow to surface. May also indicate productivity or other characteristics such as interference or boundaries.
Four Point Test
a flow test in which the flow rate is measured at four drawdowns to estimate how skin changes at each rate. Useful for identifying non Darcy skin or turbulent skin.
Choke Bean
a flow tube for a fixed bean-type choke.
Frac Plug
a flow-through plug set after pumping a frac (between stages) in a multi-fraced well and sealed with a ball dropped from surface as the next frac stage is started.
Cushion (underbalance)
a fluid column margin of some type. Usually well control mud weight, gas column, etc.
Celloflake
a fluid loss additive for cement.
Cut Fluid
a fluid that has been contaminated by an undesirable fluid.
Consistency
a fluid's ability to deform and flow and its general cohesion to itself.
BPFluxTM
a flux damage estimating system.
Defoamer
a foam breaking chemical.
FoRxo Log
a focused resistivity log that uses a pad contact with the borehole wall.
Cohesion
a force that holds fluids and sand grains together. The force is generated by attraction at the molecular level. Cohesion is often used to describe sand grains stuck together by a low viscosity fluid such as oil or water, although this is better explained as adhesion.
Abrasion (geologic)
a form of mechanical weathering where loose fragments are transported with water or wind.
Evaporite
a formation formed by the evaporation of water from shallow seas. Very low permeability.
D10/D95
a formation sizing criteria that shows impact of fines.
Disbond
a formation that comes apart or disaggregates or separation of grains.
Fault Trap
a formation that contains oil or gas that is held in place by a displaced, non permeable rock mass.
Anode, sacrificial
a formed metal bar (zinc, aluminum, etc.) attached by electrical wire to a structure to be protected and buried in conductive soil near that structure.
Annubar
a gas flow rate measurement device using Pitot tubes. Common in pipelines.
Foam
a gas in liquid emulsion. Common as a low density cleanout fluid or a frac fluid with reduced water content.
Casing Valve
a gas lift valve that is controlled by the casing or annulus gas supply pressure.
Dry Gas (in production)
a gas stream without condensate. Note: even dry gas at bottom hole conditions may have up to two barrels of water vapor per million standard cubic ft of gas. Dry gas on the process side has all liquids removed.
Damage (formation)
a general term commonly referring to an obstruction in the flow path.
Exploration
a general term covering the search for oil and gas.
Downhole
a general term referring to subsurface equipment, tools or other items.
Coke
a generally insoluble hydrocarbon that has been oxidized to the point of a solid, often hard mass.
Casing Grade
a generic grade classifying the strength of the pipe: L80, P-110, etc. The numbers are the minimum yield of the steel in 1000's of psi.
Cenozoic
a geologic epoch from today to 65 million years ago. Few major hydrocarbon bearing strata unless fluids have migrated to a trap from older source rocks.
Aquitard
a geologic formation through which no water flows. It may be an effective seal to the movement of water.
Carboniferous
a geologic time of 290 million to 365 million years ago.
Eocene
a geological epoch from 38 million to 55 million years.
Devonian
a geological time between 365 million and 405 million years ago.
Cambrian
a geological time from 500 million to 570 million years ago. Often signals the earliest hydrocarbon productive rocks.
Cretaceous
a geological time from 65 million to 140 million years ago.
Detridal
a grain of a sedimentary formation that was transported from its origin and deposited as a whole grain in the matrix of the rock.
Creaming Curve
a graph of the hydrocarbons discovered or produced in an area use to determine if new wells are improving with each new well.
Consortium
a group of unrelated companies working on a specific venture.
Crew
a group of workers on a rig.
Expendable Gun (perforating)
a gun made up of perforating charges linked together with wire or clips. The debris is not recovered on the wireline run.
Doughnut
a hanger, usually screwed onto the end of the top tubing joint and lowered into the slip bowl of the wellhead.
Chert
a hard, silicate sedimentary rock. Similar to flint, but with less ordered structure. A cryptocrystalline form of quartz.
Casing Swage or Broach
a hardened steel tool, commonly run on wireline, which is used to reshape the casing.
Case Hardened
a hardening process that hardens only the outer surface of a metal. Processes include carburizing, nitriding, flame hardening, etc.
Bit Breaker
a heavy plate that can hold the bit in the rotary table to make or break it from the drill string.
Drill Pipe
a heavy wall tubing used for drilling.
Floorhand
a helper on the drilling floor.
FLUORAZ
a high performance elastomer for seal assemblies.
AFLASTM
a high temperature seal elastomer.
Conductive Concrete
a highly conductive cement and coke based material used an impressed current anode.
Activated Carbon
a highly porous solid, usually a charcoal. Used for adsorption of unwanted materials.
Dump Bailer
a hollow tube with a flapper or other opening valve at the bottom, run on wireline to place cement or sand in a well.
Bailer
a hollow tube with a trap door or ball seat, run on wireline, which can be used to spot or remove solid material from a well bore.
Drill Motor
a hydraulic or electric motor on the end of the drill string that turns the bit.
Circulate and Weight Method
a kick control method that circulates the well immediately and mud weight is brought up gradually. (Concurrent method).
Barrel Equivalent
a laboratory measuring scale for expressing mixtures of products used to formulate muds. One gram of material added to 350 cc of liquid is equivalent to 1 lb of material added to a 42 gallon barrel.
Basin
a large area with a general containment and an often thick accumulation of rock.
Block (lease)
a large geographical lease area that may contain separate structures, proven fields or other interests.
Dike
a large igneous intrusion that cuts through the sedimentary layers, creating permeability barriers.
Arch
a large, load supporting formation that may serve to reduce the total overburden load on a pay zone. These formations may cover hundreds of square miles over a basin. A second use is as a semi-stable structure of sand grains around a perforation or other opening that keeps sand from flowing so long as the flowing pressure holds the arch in place.
Casing Plunger
a larger plunger designed to lift fluids when flowing gas up casing without presence of tubing
Blind Zone
a layer of rock that cannot be detected by seismic or in logging where the recorded resistivity is too low..
Casing Liner
a length of casing that runs from a set point to a point part way up in the previously set casing string, but usually not to surface. A liner may be used instead of a full casing string to save money, to maintain a larger ID for well equipment or to prevent creating a trapped annular space.
Cheater
a length of pipe used on a wrench to extend the leverage. (HSE risk).
Continuous Flow Gas Lift
a lift system that uses continuous injection of gas into the liquid column.
Coating
a liquid, liquefiable, or mastic composition that, after application to a surface, is converted into a solid protective, decorative or functional adherent film (NACE).
Electromotive Force Series (corrosion)
a list of elements arranged according to their standard electrode potentials.
Division Order
a list of interest owners and their share of revenues.
Ethernet (computer)
a local area network protocol standard defined by IEEE 802.3.
Distributed Temperature Log
a log of temperature along the entire length of the interval, well or flow path.
Detail Log
a log recorded on a larger scale depth than the standard correlation of 1 or 2 inches per 100 ft.
Dip Meter
a log that measures the inclination of the formation beds.
Borehole Compensated Sonic
a log that measures the interval transit time for a compression wave to move a unit of distance, usually one foot.
Carbon-Oxygen Log
a log that measures the ratio of carbon-to-oxygen within the formation. Useful for spotting oil.
Deep Propagation Log
a log that measures the resistivity of the formation.
Cross Dipole
a log with the receivers located 90o to the emitter.
Barrier Island
a long thin sandbar parallel to shore formed by wave action.
Face Cleat (coal)
a longitudinal fracture in coal.
Fish
a lost piece of equipment in the well.
Carbon Steel
a low alloy steel, containing a mass fraction maximum of 2% carbon, 1.65% manganese and residual quantities of other materials. Common in pipe manufacture.
Bow Spring Centralizer
a low to moderate strength centralizer formed by arched spring-like straps of metal.
Cessium Formate
a lower toxicity (than Zinc) weighting agent for higher density brines.
Cessium Acetate
a lower toxicity weighting agent for brine.
Fishing Magnet
a magnet, usually run on wireline, used to recover lighter metal components from the well.
Base Map
a map containing boundaries, locations and survey points.
Crosswell Tomography
a map of the acoustic strata record between two wells where the emitter is in one well and the receiver is in the other.
Coccolith
a marine, single celled (1 to 5+ micron) animal that is a component of chalks.
Bar (geologic)
a mass of sand or other materials deposited in the bed of a stream channel.
Antifoamer
a material that can quickly destabilize foam in a production fluid treating facility. Commonly needed after treatment with foamers, diesel, some polymers, some acids and gasified fluids.
Dielectric
a material that does not conduct electricity or has only a low electrical conductivity compared to a metal.
Diverter (acidizing)
a material that forces acid to enter another zone by having a higher viscosity or building a filter cake.
Cement Poison
a material that stops cement from setting.
Electrolyte
a material that, when dissolved in water, causes or increases the fluids' electrical conductivity.
Brownfield
a mature field on decline or in the final stages of productive life.
Brinell Hardness
a measure of the hardness of the material, generally measured by pushing a small ball into the surface and measuring the force used to displace the ball to a set depth.
Blaine Fineness
a measure of the particle size of a cement.
Fluid Pressure Gradient
a measurement in the well of the pressure vs. depth. Useful for spotting liquid levels, leaks, fluid entries, etc.
Fluid Loss Coefficient
a measurement of fluid loss expressed in cc/min1/2
Extreme Overbalance Perforating
a method of applying a very high pressure surge to the formation at the instant of perforating. Usually in excess of 1.4 psi/ft. Designed to overcome frac initiation pressure and break down each perf with a very short (<1 m) frac.
Driller's Method
a method of controlling a kick in which the gas is circulated out of the well using the normal weight mud controlled with backpressure of a choke. The heavier mud needed to control the formation without the choke is then circulated into the well.
Barrels of Oil Equivalent, BOE
a method of equating the energy produced by a hydrocarbon gas to a standard oil measurement. One barrel of oil has about the same heat producing capacity as 6,000 ft3 of gas at standard conditions.
Constant Choke-Pressure Kill Method
a method of killing a well where the choke is adjusted to maintain a constant casing pressure as the a water kick rises in the annulus. The method should not be used with a gas kick (will not keep a constant BHP).
Diversion (fluid treating)
a method of limiting the fluid entry into a higher permeability zone and causing the fluid to flow to a lower permeability zone.
Electric Logging
a method of rock and fluid identification or evaluation that began in 1927. The first log was run by Conrad Schlumberger.
Crystal
a mineral with a systematic internal arrangement of ions that forms a repeating outward latticework of three dimentional units.
Critical Velocity (unloading)
a minimum velocity to lift liquids in gas flow.
Dispersion
a mixture of a internal phase of solids, droplets or bubbles that stay relatively suspended in a continuous fluid.
Eutectic (brine)
a mixture of substances having a minimum solidification/melting point.
Copolymer
a mixture of two or more polymers which polymerize at the same time and with some degree to linking to yield results unlike either polymer used alone.
Brine
a mixture of water and a soluble salt. Most common brines are sodium chloride NaCl, potassium chloride KCl and calcium chloride CaCl2. Brine densities may range from 8.33 to > 19 lb/gal (1 to >2.28 g/cc). The USGS definition of a brine is a salinity of more than 35,000 mg/L (after USGS, 1984).
Aluminum Stearate
a mud degasser chemical.
Fall-Off Test
a multi-functional test that can be used to determine fracturing pressure or if the well is fractured.
Concentric Completion
a multiple completion in which the upper zone flows to the surface through the annulus formed by the casing and the deeper zone tubing. Usually used only in sweet, dry gas upper completions.
Flow-After-Flow
a multipoint flow test measuring skin at each flow rate. When plotted, the intersection of the best fit line with the y-axis (skin) at zero flow rate yields the mechanical skin.
Cleat Fracture (in coal)
a natural fracture along the cleat plane, usually parallel to max stress. Often extensive, especially in thin beds.
Carboxymethyl Starch
a natural starch used in drilling fluids.
Anionic Surfactant
a negatively charged surfactant. Normally water wets sands.
Crazing
a network of checks or cracks appearing on the surface.
Fixed Choke
a non adjustable choke that uses a flow bean for regulation.
Acrylamide Polymer
a nonionic polymer (polyacrylamide) used in flocculation, clarifying and even gelling acids and other brines. Very stable, but difficult to effectively break.
Bradenhead
a packer or packoff installed at surface on a well that enables the use of one size pipe inside another and allows flow into or out of each pipe separately.
Cup Packer
a packer with elastomer cups that are pushed out during fluid injection as the primary seal. Used for washing perfs and some testing. Only seals during fluid injection.
Equalizing Feature
a part of a plug that allows equalization of the pressures above and below a plug.
Alternate Path Technology
a patented screen design that allows gravel packing slurry to flow past an annular bridge point that would normally stop the placement of gravel.
Deep Penetrating Charge
a perforating charge with a liner shape designed to create a long penetration into the formation, but a smaller entrance hole in the pipe. See also Big Hole Charge.
Big Hole Charge (perforating)
a perforating charge with the liner shaped to create a large entrance hole but a shallow penetration. See Deep Penetrating Charge.
Exposed Guns
a perforating gun with exposed charge capsules.
Abrasive Jetting
a perforating process involving pumping a slurry of liquid and size particles through a nozzle to cut through steel and rock.
Bridge Plug
a permanent or retrievable plug set typically on wireline to isolate a section of the well.
Bleeding Core
a permeable core from which hydrocarbon escapes without differential pressure application.
Derrickman
a person that works in the derrick and assists handling pipe to make up joints into the string or stand them in the derrick when breaking out joints.
Ballooning (drilling)
a phenomenon in which fluids are lost to the rock during over-pressured operations, such as found in increased pressures from equivalent circulating density operations, and then flow back when pressure is reduced. This may be confused with a kick.
Emulsion
a physical mixture of two or more immiscible phases.
Fishing Neck
a piece of equipment on most downhole tools that is designed for simple, non-rotating attachment when retrieving.
Adaptor
a piece of equipment that connects pipe, flanges or other equipment with different root threads or connection mechanisms.
External Upset
a pipe connection with a thicker connection body than the pipe body. In an EUE, the thickness is offset to the outside diameter.
Branch Connection
a pipe connection.
Explosive Cutter
a pipe cut-off tool composed of linear shaped charge that is designed to sever pipe. Works on the same principle as a perforating charge.
Chemical cutter
a pipe cutting tool that uses boron trifluoride sprayed through a nozzle at very high velocities.
Downcomer
a pipe where the fluid flow path is down. Fluid return pipe.
Cement Plug
a plug of cement set by various methods that plugs the tubulars or the open hole.
Blanking Plug
a plug run to seal off tubing.
DG Plug
a plug that is commonly set in the tubing hanger above the tubing or in tubing immediately below the wellhead for wellhead isolation.
Crosslinked
a polymer gel with a chemical crosslinker added to link the linear gel into a higher viscosity gel.
Allocated Pool
a pool in which the total oil or gas production is restricted and allocated to specific wells as defined in a proration agreement.
Abnormally Pressured
a pore pressure higher than a column of sea water for that true vertical depth.
Cationic Surfactant
a positively charged surfactant, normally oil wets sands.
AC Test DustTM
a precision sized micron particle material used for testing the solids stopping capability of filters.
Back Pressure
a pressure caused by a restriction or fluid head that exerts an opposing pressure to flow.
Adjustable Choke
a pressure step-reduction choke that can be changed while actively flowing the well.
Casing Shoe Test
a pressure test of the casing seal, after the cement job, to the pressures necessary to safely control the pressure of the deeper zones.
Bactericide
a product that kills bacteria in the water or on the surface of the pipe.
Byproduct (reaction)
a product, sometimes undesirable, of a reaction designed to create something else.
Euler Method (seismic)
a profile or map-based depth estimation method based on a concept that magnetic fields of structures are homogeneous functions of depth and location. This is used to satisfy Euler's equation.
Collar Lock
a profile that can be set by wireline in the space in an API type coupling.
De-Bottlenecking
a program, typically in surface facilities and lines, to remove pressure drop causing flow restrictions.
Enzyme
a protein based (non-living) material that can serve as a catalyst for many organic reactions.
Block (rigging)
a pulley (sheave) or set of pulleys, mounted in a housing. The blocks on a rig are the crown (stationary) block at the top of the derrick and the traveling block.
Booster Pump (pipeline)
a pump located along the length of a pipeline to raise the pressure and overcome friction or elevation losses.
Dart
a pump-down fluid separation device. May also be used to operate tools downhole by hydraulic forces.
Berea Sandstone
a quarried sandstone with from 4500 to 9000 psi UCS, used commonly in laboratory flow testing.
Butterfly Valve
a quick opening, low pressure valve, common on large openings through which solids will move, that allows high flow rate when open.
Burr
a raised metal lip, e.g.; around a perforation.
Distillates
a range of manufactured products from the refining processes; includes kerosene, diesel, bunker C oil, fuel oil, heating oil, etc.
Crude and Crude Oil
a range of principally Carbon-Hydrogen chain compounds with generally straight carbon chain lengths of C1 (methane) to C60+. The straight chain materials are alkanes.
Explosive Decompression
a rapid reduction in pressure that may cause trapped gas to try to break out of rubber/elastomer seals and ruin the seals. Common at the surface but uncommon downhole.
Cement Packer
a recompletion technique in which cement is injected down the tubing and through a punched hole in the tubing to form a 300 to 500 ft thick seal between the tubing and the casing, often far about the bottom of the well. Useful for isolation of upper zones to shut-off unwanted fluids or separate producing horizons.
Bit Record
a record of bit run, depth, rate of penetration, etc., in a wellbore.
Deviation Survey
a record of the deviation angle and the departure usually on a depth unit basis.
Caliper Log
a recording of the diameter changes in a well made by a tool with mechanical arms that touch the wellbore or a sonic signal bouncing off the borehole wall.
Dynamometer
a recording of the stresses in a rod string of a beam pumping unit.
Bentonite
a reference to colloidal clay (generally montmorillinite or smectite), generates plastic viscosity due to clay behavior, size and electrostatic layer. A slurry of which used for P&A Purposes will weigh no less than 9 ppg.
Final Set
a reference to one of many expectations on when cement is sufficiently set to bear some type or level of weight.
Datum
a relative comparison point, such as the Kelly bushing, sea level or mud line.
Condensate Banking
a relative permeability effect where condensate, usually hydrocarbon, drops out of the vapor phase around the wellbore when the pressure drops below the dew point in response to drawdown or depletion. Gas rates can be severely reduced by the permeability reduction.
Aquicide
a relatively impermeable stratum that does not transmit water fast enough to supply a well.
Completion Bore Protector (subsea)
a removable sleeve that covers the internals of the subsea tree during drilling operations.
Corrosion Coupon
a representative piece of metal cut to a specific size and shape that is immersed in a test bath of placed in the flow stream to enable an estimation of the active corrosion occurring in a given set of conditions.
Dissolved Gas Drive
a reservoir drive mechanism in which dissolved gas from the crude oil breaks out of solution and provides energy to push the hydrocarbons toward the wellbore.
Alkyd
a resin formed by reaction of polyhydric alcohols and polybasic salts. Saturated or unsaturated oils or fats are involved.
Epoxy
a resin formed by reaction of polyols with epichlorohydrin.
Acrylic
a resin polymerized from one of several sources: acrylonitrile, acrylic acid, methacrylic acid, etc.
Bottle Neck
a restriction in a flow path.
Bottom Hole Choke
a restriction in a profile near the bottom of the well that allows some gas expansion and holds a backpressure on the formation. Rarely used, but considered for hydrate control.
Compression-Set Packer
a retrievable packer where the slips are set and the seal energized by setting tubing string weight down on the packer. Releases by picking up the string. Useful where annular pressure could unseat a tension-set packer.
Alkylation
a reverse cracking process that convents hydrocarbon light ends (olefins) into longer chain, liquid fuels.
Bingham Plastic
a rheological model used to describe flow in some fluids. Bingham fluids have a linear shear stress, shear-rate behavior after an initial shear-stress boundary has been crossed. Plastic viscosity or PV is the slope of the line. Yield Point is the threshold.
Back-Up Ring (seals)
a ridged ring-like support next to a seal to provide higher pressure or temperature support.
Corrosion Resistant Ring Groove
a ring groove lined with material resistant to metal-loss corrosion.
Clastic
a rock grain, formed somewhere else and transported into place to be part of another rock.
Directional Permeability
a rock with a higher permeability along a given plane, usually created by natural fracture development, water flow that leaches the pores, depositional environment or localized reworking of the sediments.
External Casing Packer
a rubber bladder over a section of casing that is inflated, usually with cement, to give an annular seal in open hole sections. Frequently used with liners and set at intervals along the open hole.
Elastomer
a rubber or plastic material used as a seal. May occur naturally or be synthesized.
Diapir
a salt or other column that pierces upper layers and may form traps of obstructions to flow.
Core
a sample of the formation, taken with a core barrel.
Cased Hole Gravel Pack
a sand control completion that uses a screen and a gravel pack to stop formation sand production.
Fracture Packing
a sand control technique coupling fracture treating (usually a tip screenout fracture) with a screen and gravel packing of the wellbore.
Dry Sieve Method
a sand particle size distribution obtained by shaking a sample of sand through a series of sieves or screens.
Flow Assurance
a science field dealing with prevention of scales, hydrates, asphaltene and paraffin deposits and other problems that could stop flow of fluid from the subsurface, wellhead or pipeline.
Bull Plug
a screw-in plug, normally used at the bottom of a string if no fluid entry is desired.
Dynamic Seal
a seal in a system where motion is expected in the seal or the seal area.
Fluorocarbon
a seal with good resistance to aromatic fluids but susceptible to sour gas.
Circulation Squeeze
a secondary or repair cement method using upper and lower perforations and a packer set between. Circulation is established with water and mud remover chemicals to clean the channel. Cement is circulated with a set volume pumped, then the packer is released and pulled above the zone. The cement is displaced from the tubing. A secondary squeeze may be done.
Delineation Well
a secondary well, after a field discovery well, drilled to help determine field extent, volume or potential rate.
Butt Fracture (in coal)
a secondary, discontinuous fracture.
Dead Leg (pipeline)
a section of pipeline that is not in use.
Drilling Spool
a section of the BOP that allows side ports for choke and kill lines.
Crossover (gravel packing)
a section of the treating string that transfers incoming flow from inside the pipe to the annulus below the crossover, and the return flow from inside the tubing to the annulus above the crossover. Straddles a packer.
Bowl
a section of the wellhead or of a tool what allows slips to be inserted to hold pipe or equipment.
Banded Iron Ore
a sediment with alternating layers of chert and iron rich minerals.
Biostratigraphy
a segment of geoscience where fossils are used to date or identify a reservoir.
Curvature (seismic)
a seismic comparison method useful in finding Karsts.
Coherence (seismic)
a seismic comparison method. Reverse method is incoherence.
C Factor
a selected constant in the API 14-E equation on fluid erosion.
Benchmark
a selected reference point for comparing performance.
Carrier rig
a self propelled drilling or workover rig.
Electrostatic Treater
a separation device that uses alternating current charged plates to help break emulsions.
Decision Tree (Risk)
a sequence of nodes which are either a decision or an uncertainty, and outcomes associated with each mode. The purpose of a decision tree is to define the set of scenarios and the sequence of events that guide the evaluation of risk and return.
Block Fault
a set of formation blocks, separated by normal faults into different elevations.
Casing Jacks
a set of hydraulic lift cylinders that can be used to lift casing strings.
Choke Manifold
a set of valves and/or chokes used to control drilling fluid returns on a drilling well or, in a few cases, used to control flow from a high rate well where the chokes may be in parallel or series.
Automatic "J"
a set or release mechanism where pickup or set down will release or set the tool.
Banana Blade
a shape of a reamer blade that allow milling either up or down.
Diamond bit or mill
a shaped bit body with diamonds for abrasive cutting of the formation.
Float Collar
a short piece of casing run one to two joints above the end of casing. The collar contains a backpressure or check valve which stops cement from reentering the well after displacement into the annulus. It is useful to prevent channels in the cement until the cement is set.
Bit Sub
a short section inserted between the drill bit and the drill collar.
Bent Sub
a short section of a tool or pipe that is formed at an angle or is modified downhole by a motor to assist in entering deviated wellbores or drilling off the path of the wellbore.
Crossover Sub
a short section of pipe with the proper threads cut into each end to join two pieces of pipe or equipment that do not have matching connections.
Feldspar
a silicate mineral, often modified and sometimes part of the movable particles in a formation.
Combination Log
a single assembly of various logging tools.
Bauxite
a sintered aluminum based proppant with very high strength, 3.2 g/cc density and high abrasion characteristics.
Drop Ball
a sized ball dropped or pumped from the surface to shift a tool downhole.
Button Slip
a slip for high alloy (hard) casing.
Control Line
a small diameter line, usually attached to the outside of tubing, which controls the ScSSV or other downhole tools.
Button
a small disc-shaped electrode used in micro-resistivity pads.
Cat Head
a small drum on a winch on which a hoisting cable or rope can be wrapped.
Data Frac
a small fracture treatment, without proppant, pumped into a well to assess fracture breakdown pressure, fracture extension pressure, fluid loss coefficient, frac fluid efficiency and fracture closure time.
Cat Line
a small hoisting rope or cable.
Capillary
a small passage, usually between rock grains. These passages may have ability to absorb fluids and the pressures necessary to expel the fluids may vary inversely with capillary diameter.
Barrel Pump
a small, usually hand driven pump with a long dip tube used to move chemicals from drums and barrels.
Bituminous Coal
a soft coal, intermediate in coal development, containing 15 to 20% volatiles.
Fracturing
a stimulation method involving injection of fluid into the well at a high enough pressure to break the rock. Fracturing "failure" of the rock is a tensile failure as the wellbore in enlarged by pressure.
Blooie Line
a straight through flow line from the wellhead to a flare pit. Often used in diverting flow during a well control incident.
Dendritic Drainage
a stream system that branches irregularly.
Corridor
a strip of land or water through which a concession is obtained to run pipelines, electrical power, etc.
Caustic
a strong base chemical. Caustic soda is sodium hydroxide.
Braided Wireline
a strong, braided wireline of various sizes used in retrieving tools heavier than slickline can handle. Electrical line is a braided line with a center conductor.
Alkali Metal
a strongly basic metal such as sodium or potassium.
Alkali
a strongly basic solution.
Circulation Sub
a sub in the circulating string with a side port that can be opened remotely to allow circulation from that point.
Bed
a subdivision of the classification of a sequence of rocks. A bed usually has similar lithographic features and is separated from other groupings by recognizable boundaries.
Catenary Riser
a subsea riser with a large "S" that allows flexing and movement of the line.
Anodic Inhibitor
a substance that slows the reaction at the anode.
Colloid
a substance with particle size so fine that it exists as a stable dispersion rather than settling out.
Dog Leg
a sudden change in the direction of the wellbore. Generally based on degrees per 100 ft.
Drilling Break
a sudden increase in the ROP (rate of penetration) while drilling. May indicate a higher pressure formation, a change in lithology, a naturally fractured zone, or a poorly consolidated zone.
Flash Liberation
a sudden pressure drop that causes hydrocarbon light ends to go from a liquid to a gas.
End of Well Report
a summary of general well data, operation data, geologic data, etc., for a particular well after the final completion step.
Casing Hanger
a support that is screwed onto the casing and fits into the casing head.
Blistering (elastomer)
a surface deterioration caused by gas trying to escape too rapidly from a elastomer and tearing the surface of the material.
Air Lift
a surface piston driven pumping unit, similar to a beam lift unit.
Conformity
a surface separating younger from older rocks with no indication of erosion or other disturbance.
ChicksanTM
a surface treating line connector that allows quick, pressure tight bends in high pressure pipe.
Amphoteric Surfactant
a surfactant whose charge is dependent on another variable, normally pH.
Aerosol
a suspension of fine liquid droplets or solid particles in a gas.
Dome
a symmeatrical upfold of the layers of rock in which the beds dip in all directions more or less equally from a common point; any deformation characterized by a circular local uplift.
Casing Shoe
a tapered guid shoe on the bottom of a casing string to assist in passing ledges and dog-legs in the wellbore.
Free Point
a technique for estimating the highest free point in a string of stuck pipe. It is based on a differential stretch calculation with amount of pull and the free point constant (FPC).
Frac Ball
a technique for isolating multiple fracs using a short downhole settable ring or restriction and dropping a hard rubber ball between frac jobs. Two or more ring/ball sets can be used to stage frac a long zone.
Cement Retainer
a temporary set plug to allow cement work above the tool. It is drilled out after the cement job.
Axial Load
a tension or compression force, usually along the length of an object.
Casing Head
a term that applies to the wellhead flange that forms the transition between pipe and the flange-build tree. It may be attached by threads, welding, pressure forming or lock-ring/screw devices.
Compliant Expansion
a term used in expandable nomenclature signifying expansion that fits itself to non-gauge boreholes.
Durometer (rubber)
a term used to express hardness, usually of rubbers or elastomers.
COFCAW
a tertiary recovery mechanist consisting of combustion and water flooding.
Fire Flood
a tertiary recovery method involving injection of air into the formation and igniting the oil. Under the right conditions, the heat produced from combustion of the heavy ends that are trapped on the sand grains lowers the oil viscosity and liberates light ends.
Flow Loop
a test loop of pipe in which flow characteristics are measured.
Bioaccumulation
a test measuring the concentration or build-up of potential harmful chemicals in a living organism.
Formation Integrity Test
a test of the fracture initiation pressure.
Coupon
a test strip of metal used in corrosion and erosion testing.
Abiogenic Theory
a theory of petroleum generation in which petroleum is thought to have formed from hydrocarbons trapped inside the earth's crust when the earth was forming. See also Biogenic and Organic theories.
Bomb
a thick walled pressure container of pressure measuring instruments or a sample container.
Flow Coupling
a thicker body piece of tubing above and sometimes below a tubing profile or other tool to control erosion by fluid flow.
Eight Round
a thread with 8 threads per inch.
Flow T or Tee
a three-way connection. In a wellhead, a flow cross connects the master valve and the swab valve with the wing valve.
Epoch
a time division of geologic time next shorter than a period.
Below Rotary Time (drilling)
a time that reflects the slide time in which the pipe is not rotating and drilling.
Cat Walk
a tool assembly/staging area before the Vee Door on a rig.
Bottom Hole Sampler
a tool that takes bottom hole samples of fluids or solids.
Back Reamer
a tool to enlarge a drilled hole.
Dies
a tool used to shape, form or finsih other parts.
Drift (tool)
a tool with a set diameter used to check the wellbore for clearance prior to running a tool string or piece of equipment.
EconoPropTM
a trademarked name for an inexpensive light weight ceramic (man made) proppant.
CarboPropTM
a trademarked name for ceramic (man made) proppant.
Echo MeterTM
a trademarked, commercial tool that measures the height of a fluid (or solid) level by means of a reflected sound wave.
Black Oil
a traditional crude oil, containing alkanes (straight carbon chains) of C5 to C30+ liquids.
Athie Wagon
a trailer or other vehicle, designed for soft ground, often used as the staging platform for fighting well fires.
Butt Cleat (coal)
a transverse fracture.
Combination Trap
a trap that has both structural and stratigraphic character.
Dehydrator
a treating vessel designed to remove water from a process stream.
Check Trip
a trip back to bottom after a cleanout or other operation, to check for clearance.
Dip Tube
a tube from the intake of a pump that extends further into the liquid column of the well, to keep gas out of the pump.
Ethane
a two carbon chain alkane, C2H6. A gas under standard conditions of temperature and pressure.
Ethylene
a two carbon chain alkene - double bonds between the carbons and a formula of C2H4. A very common starting material for synthesis of various products.
Collapse Chimneys
a type of Karst (geologic time sink hole).
Collett Connector (coiled tubing)
a type of connector that utilizes a collett-type device for attaching a BHA to coiled tubing.
Bi-Metal Corrosion
a type of corrosion found when dissimilar metals are joined. One part becomes the cathode and the other the anode where accelerated corrosion may be seen.
Cut Lip Guide
a type of cut on the bottom of an overshot that, when rotated, can help center the end of a pips that is laying against the side of the hole.
Chamber Lift
a type of gas lift that uses the tubing-casing annulus for accumulation of produced liquids between lift cycles.
Chain Tongs
a type of hand or power operated wrench used to make up connections in pipe.
Back-in (contract)
a type of interest in a well or least that becomes active at a specified time or a specified event.
Collett Lock
a type of lock used in a profile.
Dog-Lock
a type of lock used in a profile.
Compressor
a type of pump that increases the pressure of gas. Commonly used as a production rate increaser by increasing the gas pressure delivered from low pressure gas wells to enter the pipe line. The intake into the compressor lowers the wellhead pressure creating a larger drawdown.
Duplex pump
a type of pump with two, dual acting pistons.
Fish Hook
a upward turning horizontal well - usually over 90o.
Check Valve
a valve that only allow flow in one direction.
Flint
a variety of chert.
Bar-Vent (perforating)
a vent in the tubing or treating string open by a drop bar used to fire a perforating gun.
Absorber
a vertical, cylindrical vessel that recovers heavier (longer carbon chain) hydrocarbons from a mixture of lighter hydrocarbons.
Drill Collar
a very heavy wall pipe used to add weight over the bit during drilling.
Barefoot Completion
a very simple, open hole pay zone completion with a minimum of downhole equipment. Also called an open hole completion. The casing is usually run to the top of the pay and is cemented above the pay only.
Float Shoe
same function as a float collar but run on the end of the casing.
Capillary String
a very small string, usually run along the outside of the tubing and banded to the tubing. Commonly used for hydraulic control of safety valves and sliding sleeves. May also transmit bottom hole gauge data.
Acetic Acid
a very weak organic acid used for minor and shallow damage removal. Also used as a moderately effective iron precipitation preventer. 4% acetic acid is vinegar.
Accumulator (processing plant)
a vessel that receives and temporarily stores a liquid used in the feed stock or the processing of a feed stream in a gas plant or other processing facility.
Brookfield Rheometer
a viscosimenter use for some fluid measurements, particularly when solid suspension properties are needed.
Aquifer
a water containing formation that may or may not be directly connected to the hydrocarbon bearing zone. A connected aquifer may or may not offer pressure support to the pay.
Bright WaterTM
a water control product.
Citric Acid
a weak organic acid that serves as a chelating agent for iron (slows iron hydroxide formation).
Field Weld
a weld repair made in the field. Usually derates the equipment pressure or tensile rating.
Bias Weld
a weld technique on diagonal cut strips of steel, superior to the butt weld process for joining flat strips of metal together before rolling into coiled tubing.
Butt Weld
a welded connection using two pipe ends, cut straight across and welded together with minimum circumferential contact.
Complex Well
a well design with engineering or application challenges that are out of the ordinary.
Dilatant Fluid
a well dispersed, high solids content liquid that has very high apparent viscosity with any applied shear.
COST Well
a well drilled on the continental margin to provide data for offshore leases.
Disposal Well
a well into which fluids such as produced water and some liquid wastes can be injected. It is in a non hydrocarbon, non-fresh water sand and is not connected to the hydrocarbon bearing formation.
Compensated Log
a well log that is designed to correct for an effect associated with the borehole.
Five Spot Pattern
a well placement pattern that looks like the 5-spot side on a dice cube.
Concurrent Method
a well pressure control operation in which circulation is started immediately and mud density is brought up in steps until the well has been completely circulated to the kill weight fluid.
Dry Hole
a well that does not have or produce commercial deposits of hydrocarbons.
Flowing Well
a well that flows to the surface by produced gas expansion and does not use any method of artificial lift.
Completed Well
a well that has been drilled, cased and cemented and is ready to produce hydrocarbons.
Dead Well
a well that will not flow on its own through natural gas lift or by reservoir pressure.
Deviated Well
a well with an inclination other than zero degrees from vertical. In practice, deviated wells are usually more than about 10o from vertical.
Crooked Hole
a wellbore drilled in excess of the maximum allowable dogleg.
Exploration Well
a wildcat or well in a new area with unknown producing potential.
Dummy Run
a wireline or tubing run into a well with a dummy piece of equipment of the same size, shape and stiffness of a valuable or unrecoverable piece of equipment to make sure the equipment can be placed.
Collar Stop
a wireline set plug without a profile. It is set in a coupling and grips with packer-like slips.
Electric Line or E-Line
a wireline with a conductor in the middle and woven electrical braid over the conductor.
Concentric Tubing Workover
a workover using a small diameter tubing inside the existing tubing. Usually done with a hydraulic workover rig or coiled tubing. Commonly used with a positive surface well pressure and seals on the smaller tubing in a live-well workover.
Cage Wrench
a wrench for connecting the cage of a sucker rod pump to the rod string.
Communication
ability to circulate or pass fluids from one chamber in a well to another.
AOFP
absolute open flow potential.
ADP (training)
accelerated development program.
AQL
acceptance quality level.
Fouling
accumulation of deposits on a surface.
Consolidated
an approximate level of rock strength where sufficient cementation is present to allow the rock to remain intact during drilling and production. Often the unconfined compressive strength is greater than 1000 to 1500 psi.
Benzene
an aromatic (cyclic or ring structure) compound, present in very minor quantities in many crude oils.
Beam Pump
an artificial lift system, common to low pressure, lower rate oil wells, with a plunger type bottom hole pump operated from the surface by a rod string.
Bituminous Coating
an asphatic or tar based protective surface coating.
Fischer Assay
an assay method for organics in rock by pyrolysis (burning).
Daughter
an atom that results from the radioactive decay of a parent atom.
Band or Banded
an attachment strap to affix cable or capillary tube to the outside of the tubing.
Cable Tool Rig
an early drilling rig that uses a heavy chisel bit on a cable, dropped vertically, to pound through rocks.
Accumulation (reservoir)
an economic quantity of hydrocarbon trapped in a permeable rock strata.
CHEMRAZTM
an elastomer used in seals.
Electrical Submersible Pump or ESP
an electrical powered rotating pump capable of lifting very large flow rates (>20,000 BPD).
Beta Particle
an electron emitted with high energy and velocity from a decaying nucleus.
Bar-Finger sand
an elongated lens of sand formed during distribution of sediment in a delta.
Archie Equation
an empirical relationship between the formation resistivity, F, and porosity, , in which F=1/m, where the porosity exponent or cementing factor, m, is a constant for a particular formation. Typical m's are 1.8 to 2.0 for consolidated sandstones and 1.3 for poorly consolidated sandstones.
Accelerator (drilling)
an energy increasing device, with sudden energy release, used in a jarring string while fishing.
Bean-Up Strategy
an engineered sequence of choke settings in the start-up of a well to apply stresses in the formation in a manner that will strengthen the formation and avoid failure.
Breakout (drilling)
an enlargement of the borehole.
Archean
an eon of geologic time extending from about 3.9 billion to 2.5 billion years ago.
Aggregate (cementing)
an essentially inert mixture of particles of a particular size range.
Deterministic Estimate (Risk)
an estimate using a single number value. It does not account for ranges in value or probability of occurrence for the parameter.
Bearden Unit of Consistency
an estimation of the pumpability of a slurry. Has no direct correlation to viscosity.
Collider
an explosive charge in a tool designed to sever very heavy BHA tools such as drill string collars and stabilizers. It latterly uses a focused explosive to blown the string apart. A tool of last resort.
Control Head
an extension of a retrievable tool that is used to set and release the tool.
Flash Point
an ignition temperature (given in oF) that liquid will put off enough vapors to be ignited.
Black Shale
an in determinant term generally meaning a shale with a higher organic content than a brown or gray shale.
Elongation
an increase in length expressed numerically as a percent of initial length.
Ballooning (pipe)
an increase in pipe O.D. as internal pressure is applied (shortens pipe) or a decrease in diameter (Reverse Ballooning: lengthens pipe) as external pressure is applied.
Dual Induction Log
an induction log with dual and deep measurements of resistivity. Shallow measurements are indicative of severely invaded zone and the deepest measurements are most reflective of actual formation fluids.
Blasting Cap
an initiating or detonating device in an explosive.
Channel (formation)
an interconnected pathway through the matrix of the rock or an open fracture or other feature that connects a reservoir and the wellbore.
Aluminum Activation Log
an investigation that focuses on aluminum content, an indirect measurement of clay content.
Capital Asset
an investment or asset that can create a produce or service that will produce income.
Anion
an ion with a negative charge.
Cation
an ion with a positive charge.
Batholith
an irregular intrusion of an igneous rock into another rock.
Bead Tracer
an isotope tracer in a bead with the same density of the flowing fluid that is used to track fluid flow rates and therefore fluid entry and exit points along the wellbore.
Block (flow)
an obstruction to flow, either partial or full.
Formation Damage
an obstruction to flow. Usually a reduction of permeability.
Biogenic Gas
bacteria generated natural gas, found at shallow depths and in many water wells. Usually contains C14 isotope. See also thermogenic gas as a gas that has a biological origin but has been modified from the original organic state by time at temperature and other effects to produce a gas with no C14.
Anaerobic (bacteria)
bacteria that can survive and multiply without oxygen.
Facultative (bacteria)
bacteria that can survive either with or without oxygen.
Aerobic (bacteria)
bacteria that require oxygen to survive and multiply.
BL
balance line.
BOSS
ball operated shear sub.
BOMA
ball out mud acid.
Ball Diverter
ball sealer.
BV
ball valve.
BaSO4
barium sulfate.
BPM
barrel per minute.
BLPD
barrels of liquid per day.
BOE
barrels of oil equivalent. A method of equating the energy produced by a hydrocarbon gas to a standard oil measurement. One barrel of oil has about the same heat producing capacity as 6,000 ft3 of gas at standard conditions.
B/D
barrels per day.
BPD
barrels per day.
BWPD
barrels water per day.
BKB
base Kelly bushing.
BFE
base flange elevation.
BF
base flange.
BMX
base management excellence.
BMT
base management team
BOC
base operations camp.
Alkaline
basic or pH over 7.
BOD (design)
basis of design.
BG
bell guide.
BML (subsea)
below mud line. BMP: best management practice.
BRT (drilling)
below rotary table.
BM
benchmark.
BSR
bending strength ratio.
BTX
benzene, toluene, xylene.
BtBcp
beyond the best common process.
BtB
beyond the best.
Bicarb
bicarbonate of soda, used in acid neutralization operations.
BH (perforating)
big hole charge.
Bcf
billions of cubic feet.
BOD (reaction)
biochemical oxygen demand.
BOP
blow out preventer.
Ferrite
body centered cubic crystalline phases common to iron based alloys.
BHPI
borehole pressure integrity.
BHA
bottom hole assembly.
BHCP
bottom hole circulating pressure.
BHCT
bottom hole circulating temperature.
BHCIP
bottom hole closed in pressure.
Bacterial Degradation
breaking down alkanes by bacterial action. Common by psedomonis and ultramonis bacteria and other bacterial strains that digest parts of the crude oil structures. Useful for remediating oil spills or tank bottom residuals.
Cracking (refining)
breaking longer chain hydrocarbon molecules to shorter chain molecules.
Environmental Cracking
brittle fracture of a normally ductile material in which the corrosive effect of the environment is a cause (NACE).
BUR (drilling)
build up rates, increase in well inclination during drilling.
Air Can
buoyancy device on a Spar.
Deadman
buried anchor.
Deflagration
burning, decomposition or low order detonation of explosive.
BU
business unit.
BWOC
by weight of cement.
BWOB
by weight of the blend.
BWOW
by weight of water.
CMTD
cable mounted tension device.
CRI (structure)
caisson-retained island.
CaBr2
calcium bromide.
Calcite
calcium carbonate, CaCO3. May be rock (limestone) or a scale formed from super saturated solution at the site of a chemical or physical upset.
CaCO3
calcium carbonate.
CaCl2
calcium chloride salt.
Calcium Treated
calcium or other divalent ion added to a fluid to inhibit shale or clay dispersement.
CaSO4
calcium sulfate
Dolomite
calcium/magnesium carbonate rock. Dolomite is formed by chemical modification of a limestone.
CAOF
calculated absolute open flow. A theoretical figure of a wells maximum production.
Accumulator (pressure control device)
canisters of hydraulic fluid, pressurized with a nitrogen gas cap of sufficient pressure and volume to operate all the rams on a BOP in case of power failure to the BOP.
CAP
capacity.
CST (rock)
capillary suction time.
Finding and Development Costs
capital costs from acquisition, exploration, drilling and completion costs of proved reserves.
CAPEX
capital expenditure.
CBJ
carbide blast joint.
Cutrite
carbide particles in a metal binder. Applied to the cutting surfaces of mills.
Aliphatic
carbon and hydrogen compounds that may be branched of straight chained. Aliphatics may be paraffin (saturated) or olefinic (unsaturated).
CO2
carbon dioxide.
CO
carbon monoxide.
Dead Carbon (shale)
carbon with a type of Kerogen content that has low potential to generate hydrocarbons (generally woody carbon).
CMC
carboxy methyl cellulose.
CMS
carboxy methyl starch.
CMHPG
carboxy methyl, hydroxyl propyl cellulose.
CWI (contract)
carried working interest.
C&P
cased and perforated.
CHFRTM
cased hole formation resistivity tool.
CHFP
cased hole frac pack.
CHL
cased hole log.
CCP (completion)
cased, cemented and perforated.
CCL
casing collar locator log.
CIT-OA
casing integrity test - outside annulus.
CIT (pressure test)
casing integrity test.
CP (casing)
casing point.
Conchoidal Marks (failure/crack development)
characteristic markings (ridges, tears, risers, etc.) on fracture surfaces after fatigue crack of fracture propagation (also known as beach marks, clamshell marks and arrest marks).
Clamshell Marks (failure/crack development)
characteristic markings (ridges, tears, risers, etc.) on fracture surfaces after fatigue crack of fracture propagation (also known as beach marks, conchoidal marks and arrest marks).
Beach Marks (failure/crack development)
characteristic markings (ridges, tears, risers, etc.) on fracture surfaces after fatigue crack of fracture propagation (also known as clamshell marks, conchoidal marks and arrest marks).
CV
check valve.
Acid Flowback Analysis
chemical analysis of the acid concentration and other chemical and physical measurements in the returning acid.
Coal liquefaction
chemical conversion of coal to a liquid hydrocarbon.
CDR (flow)
chemical drag reducer.
CHESS
chemical hazard employee safety system.
CID (subsea)
chemical injection for downhole.
CIT (subsea)
chemical injection for tree.
CIV
chemical injection valve.
COD
chemical oxygen demand.
Exothermic
chemical reactions that gives off heat.
Anti-agglomerants (hydrate control)
chemicals which prevent hydrate crystals from sticking together and forming a larger mass.
CHKS (rig up)
chicksans
Cuttings
chips of rock from the drilling process. They are circulated to the surface by the mud and separated in the screens and shaker. They are useful for identifying and correlating the formation.
ClO2
chlorine dioxide, a powerful biocide that dissolves biomass cell walls. It is nearly impossible for bacteria to develop immunity against ClO2.
C/K (drilling)
choke and kill line.
CLFP
choke line friction pressureClinker: pea to marble sized pellets of raw cement prior to grinding.
CHK
choke.
Cr
chrome. 13Cr is 13% chrome.
CO
circulate out, mud logging term.
Condition the Mud
circulate the well to remove cuttings and gelled mud prior to running the casing.
CIRC
circulate.
CBHT
circulating bottom hole temperature.
Bottoms Up
circulating the bottom hole fluid to the top of the well.
Bracelet Anodes
clamshell-type rings of anodes that clamp around a pipeline.
CWA
clean water act, a US law.
CCDST
closed chamber DST.
CIBHP
closed in bottom hole pressure.
CIWHP
closed in well head pressure.
CBM
coal bed methane.
CBNG
coal bed natural gas.
Fossil Fuel
coal, natural gas or oil.
CTE
coefficient of thermal expansion.
CTDESP
coiled tubing deployed electric submersible pump.
CTD
coiled tubing drilling.
CTL
coiled tubing logging.
CTU
coiled tubing unit.
CNL
compensated neutron log. Radioactive neutron source bombards the formation with high energy neutrons, which are slowed and captured by atoms of the formation. The low energy neutrons are reflected back to the tool and counted. The amount of neutrons returning is inversely proportional to the porosity of the formation.
CSDTM
compensated spectral density log.
CWOP
complete well on paper exercise.
Flanged Up
completed.
CWOR
completion and workover riser.
CF
completion fluid.
CIV (completion)
completion isolation valve.
CE
completions engineer.
CVAR (subsea)
compliant vertical access riser.
ERFC(x)
complimentary error function = 1 - erf(x).
Biological Marker
compounds found in petroleum or rock extracts that possess a carbon chain or skeleton that contains a link with a natural product. Common biomarkers in petroleum include isoprenoids, triterpanes and steranes.
CNG
compressed natural gas.
Corkscrew
compressional deformation of tubulars to the point where the tubing resembles a corkscrew. The condition may be temporary if the metal is not yielded past the elastic recovery point. Tubulars that are corkscrewed may be pumped through but will stick most diameters of tool strings.
CFD (fluids)
computational fluid dynamics.
CCT
concentric coiled tubing.
CGR
condensate gas ratio.
Drip
condensate liquid, or natural gasoline.
Anoxic
conditions where concentration is very low, usually less than 0.1 mg/liter of water.
CATs (subsea)
connection actuation tool.
CG
connection gas, mud logging term.
Exponential Decline
constant percent decline of production rate over time.
Class A Cement
construction grade Portland cement.
Drilling Ahead
continue with drilling after stopping to check flow or other activity.
CD (contract)
contract demand.
Balancing Agreement
contractual agreement between legal parties to account for differences between chart measured quantities and the total confirmed quantities at a measuring point such as a plant. They are used to track over/under production relative to entitlements between producers; over/under deliveries relative to measured volumes between operators of wells, pipelines and LDCs.
Cap A Well
control a blow out or seal at the surface after a P&A.
CLW (SSSV)
control line to well communication.
CL
control line.
COE
controllable operating expense.
CTR
controlled tension release tool. A release tool for downhole.
Bending Cycle (coiled tubing)
cycling coiled tubing from a yielded position, through a transition region, and back again. Running coiled tubing from the reel into a well and back to the reel involves six bends or three cycles.
DDR
daily drilling report.
DAS
data acquisition system.
Depth Migration (seismic)
data processing used to shift subsurface signals to their proper depth.
Daylight Tour
day working shift.
Eccentricity
decentralization of pipe in the hole. 100% eccentric is against the hole wall.
DDCV
deep draft caisson vessel.
DWP
deep mater production.
DPT
deep propagation log
DWD
deep water development
DW
deep water, usually inaccessible by a fixed (non floating) platform.
DFP
deferred production.
Elastic Deformation
deformation of a body in the elastic range, i.e., recovery to the initial shape is possible when the stress or load is removed.
DZO (seismic)
demigration to zero offset. An improvement in seismic processing over dip movement offset where signal velocity varies significantly with depth.
Fragipan
dense layer of soil containing silt and sand, but no organic matter and little clay. May have extreme hardness due to compaction.
Density Contrast (seismic)
density of one rock relative to another. The contrast can be positive or negative. Gravity anomalies within sedimentary sections can be analyzed as structural or lithologic anomalies.
Creaming of Emulsions
density separation state of emulsions, often where color variances are noted.
DD&A
depletion depreciation and amortization.
DP (reservoir)
depletion plan.
Abyssal
depositional environment of the deepest areas of the oceans.
DCS (pipe)
depth control sub.
DC
depth correction.
Fluid Contact
depth of the contact point in a specific well between immiscible phases.
DF
derrick floor.
Biot's Constant
describes the relationship between pore pressure and stress
Aromatic (chemical)
describing members of a family of chemicals with a ring structure of carbon chains. Normally xylene, toluene, etc. Benzene is a aromatic but is not used.
Check Shot Survey (seismic)
determines formation seismic wave velocities over specific intervals. Measurement is made of travel time from surface to downhole geophones.
Exploitation
development of a producing reservoir.
Desander / Desilter
devices that typically use centrifugal flow paths to spin solids out of a drilling or circulating fluid.
Deaerator
devices used to separate gasses from liquids.
DFIT
diagnostic fracture injection test.
D/t
diameter to thickness ratio, a common comparison value in steel pipe.
DPTA
diaminopropanoltetraacetic acid, a calcium scale remover and solvent.
DE (filter)
diatomaceous earth filtration unit.
DSL
diesel.
Anisotropy
differences in rock - segments showing different responses when measured.
Dissimilar Metals
different metals that may form an anode-cathode pair in corrosion cell conditions.
Dip Log
dip meter log.
DMO (seismic)
dip movement offset. The difference in arrival times at various sensors due to the dip of the surface off of which the signals are reflecting.
DSI
dipole sonic.
DXV (subsea)
direct crossover valve.
DS
directional survey.
DCF (accounting)
discounted cash flow.
Deflocculation
dispersing a clump or a gathering or "flocculated" of particles. Usually accomplished by dispersants or solvent thinners.
DCS
distributed control system.
DTS
distributed temperature sensor or survey.
DLS
dog leg severity.
DB&B
double block and bleed.
DSV
down hole safety valve.
DHC
downhole controller.
DHD
downhole diagnostics.
DHFC
downhole flow control.
DHPG
downhole permanent gauge.
DPU
downhole power unit.
DHSV
downhole safety valve.
Drillable
downhole tools and equipment that can be broken up by the bit.
DHV
downhole video.
DRA (flow)
drag reduction agent.
DD
draw down.
DC (drilling)
drill collar.
DIF
drill in fluid.
Final Circulating Pressure
drill pipe pressure required to circulate at the selected kill rate.
DS
drill site.
DS
drill string.
DWOP
drill well on paper exercise.
DMD
driller's measured depth.
D&C
drilling and completion.
DWOP (BP)
drilling and well operations policy.
DE
drilling engineer.
Drilling Out
drilling out set or green cement from the casing before drilling ahead to make a deeper well.
Directional Drilling
drilling the wellbore in a planned angle of deviation or trajectory.
Drill Out
drilling through the cement after a primary cement job as the hole is deepened.
Air Drilling
drilling with air instead of drilling mud (requires diverters at the surface to handle cuttings and formation fluids).
DMUR
drilling, milling and under-reaming.
DRODB
drilling, recompletion and repair data base.
DRGL
drilling.
DDB
drive down bailer.
Clay Flocculation
dropping suspended particles out of a fluid by agglomerating them into larger, easier separated particles.
Anhydrous
dry - without water.
D&A
dry and abandoned.
DIL
dual induction log.
DLL
dual laterolog
DNL
dual porosity CNL.
DGLV
dummy gas lift valve.
DB
dump bailer.
DUB (perforating)
dynamic underbalance perforating.
DP (offshore rig)
dynamically positioned.
EM
eddy current measurement for wall thickness in corrosion and wear determination.
ELG
effluent limitation guidelines.
Bottom Hole Temperature
either static (non circulating, non flowing and stable), flowing, or circulating) - temperature at the bottom of the well.
eCTU
electric line coiled tubing unit.
ELMD
electric line measured depth.
ESP
electrical submersible pump.
EPT
electromagnetic propagation tool. Measures propagation time and attenuation rate of microwave energy through the formation. Helps distinguish between oil and water.
EMF
electromotive force. The force that drives electrons and creates an electric current.
EIT
engineer in training.
ETP (BP)
engineering technical standards.
EXHTTM (subsea)
enhanced horizontal tree.
EOR
enhanced oil recovery.
EVXT-DB (subsea)
enhanced vertical tree, dual bore.
EVXT-SB (subsea)
enhanced vertical tree, single bore.
EVXTTM (subsea)
enhanced vertical tree.
EIS
environmental impact statement.
EP
equalizing prong.
ES (wireline)
equalizing sleeve.
EOS
equation of state.
Coleman Equation
equations for deliquification of a well at operating pressures less than 1000 psi.
ESR
equilibrium step rate test.
ECD
equivalent circulating density.
De (hydraulics)
equivalent hydraulic diameter.
EMW
equivalent mud weight.
EQMW
equivalent mud weight.
ESD
equivalent static density.
EPM
equivalents per million. The epm is equal to the ppm divided by the equivalent weight.
Corrosion-Erosion
eroding away of a protective film of corrosion product by the action of a process stream, exposing fresh metal which then corrodes.
ERF
error function
Circulate
establishing flow down the tubing or drill pipe and up the annulus. Reverse circulating involves injecting down the annulus and up the drill pipe.
Absolute Ages
estimation/measurement of age of a formation, fossil, etc., in years before the present.
Ethanol
ethyl alcohol.
EDTA
ethylene diamene tetra acetic acid.
EGMBE
ethylene glycol mono-butyl ether. A mutual solvent.
Dynamic Event (propellant fracturing)
events such pressure surge or fracturing that occur over a few hundred milliseconds.
ESS (sand control)
expandable sand control screen.
Casing Cladding
expanding pipe installed in production casing or tubing to seal perforation holes or leaks caused by corrosion or erosion. Can be metal or plastic.
EUR
expected ultimate recovery from a field.
E&A
exploration and appraisal.
E&P
exploration and production.
ESS (seismic)
exploration sub salt.
EL&P
exploration, land and production.
ED (elastomers)
explosive decompression.
Detonating cord
explosive wrapped with elastomer in the shape of a cord. Used to link and detonate charges in perforating guns.
FGLR
formation GLR.
Cement and Cementation (formation)
formation binding agents (calcite, clay, silica overgrowth, heavy oil, etc.) that hold the formation grains together.
FBP
formation breakdown pressure,. The pressure at which the fracture initiates.
FCV
formation control valve.
FDCNL
formation density compensated neutron log.
FDC
formation density log.
F (logging)
formation factor.
FF
formation factor.
FIV
formation isolation valve. A downhole valve that is operated by pressure cycling or other remote method.
FMI
formation micro image, a common fracture detection tool.
Bo
formation oil volume factor.
FPWD
formation pressure while drilling.
FRA
formation rate analyser, a well performance test method.
F (reservoir)
formation resistivity factor, dimensionless.
FMWTR
formation water.
Acoustic Basement
formations below the deepest zones that can be imaged by an acoustic process.
Authochthonous
formations that formed in the present locations and have not been transported.
Allochthonous
formations transported by fault or similar earth shift movements.
Eolian
formed by wind.
BP
formerly British Petroleum.
Coagulation
forming a larger mass from smaller ones by collision and sticking together.
Agglomeration
forming larger droplets, bubbles, or particles from smaller droplets, bubbles, or particles.
FIT (fracturing)
frac isolation tools.
FCD
fracture capacity - a comparison of the conductivity of the fracture to the capacity of the formation.
FCP
fracture closure pressure. A measurement of the pressure at which the fractured formation closes. Generally determined by the change in slope of the pressure reading as leakoff gradually lessens the volume of fluid that is holding the fracture open, until the fracture walls meet and the pressure reverts to a decline to pore pressure.
FCS (fracturing)
fracture closure stress.
Fg
fracture gradient.
FPP
fracture propagation pressure.
Breakdown
fracture.
Breccia
fragmented (not wear rounded) grains. Rock along moving faults may have this texture.
Blowdy
free gas separating from the liquid at the bottom of the separator. Generally indicates poor separator performance.
FPIT
free point indicator tool.
FFM
full field model.
FO
full opening.
Bottom Hole Gas Separator
gas anchor or a separator used in front of a pump to deflect most of the free gas to improve pump efficiency.
CCP (compression)
gas compression plant.
Entrained Gas
gas dispersed in a produced fluid.
Ditch Gas
gas removed from the mud at the flowline by mechanical means.
Free Gas
gas that is not dissolved in the liquid.
Cycle Gas
gas that is separated and reinjected.
Blue Gas
gas volume that separates from produced water.
Azimuth (logging)
in a horizontal plane, it is the angle (measured clockwise) of well path departure usually from true or magnetic north. It may also be expressed as the compass direction of the path of the well bore as measured by a borehole survey. (Note: check the specifics of the survey for the details).
Bottom Plug
in cementing, the first plug pumped in cementing with the two plug system. It isolates the mud and cement slurry and allows passage of the cement slurry when the plug "bumps" or reaches the float shoe or float collar. It is hollow with a diaphragm that is ruptured by pressure.
Dead Time
in radioactive logging, the length of time that the system requires to recover after counting an event.
Brackish Water
indefinite term meaning water with small amounts of salt. Saltier than fresh water.
Bag-Off
inflatable devices in a pipeline meant to stop flow.
Feed In
influx into the well bore.
Formation Breakdown
initiating a fracture in the formation.
Flood
injection of gas or water into a reservoir to drive oil towards a producing well or set of wells.
Effective Porosity
interconnected, drainable porosity.
Aeration
intoduction of air.
FeCO3
iron carbonate scale.
FeOH
iron hydroxide gel (a precipitate after acid spends).
Brownian Motion
irregular motion of colloidal sized particles when suspended in a fluid. The effect in simplest terms is caused by thermal driven motions.
Alluvial Fan
land counterpart of a river delta. Characteristic of sediments that have been transported by a fast moving stream then dropped out of the flow as the stream velocity drops as it spreads out. Typical of zones of heavy water runoff such as found at the base of mountains in arid and semi arid climates where flash floods may be seen. Often poorly sorted with pebble to boulder sized sediments. Weak cementing typical.
Acreage
land leased for drilling exploration.
Fee Land (contract)
land where mineral and surface rights are controlled. Usually private lands, rather than public or government.
Caisson (pipe)
large outer pipe, often a form or a barrier.
Alkaline Flooding
large scale injection of pH>7 fluids. The basic materials may react with oils to form reactants that can reduce viscosity or affect wetting.
Abyssal Plain
large, flat ocean floor, usually near a continent and usually over 4km (13100 ft) ss.
Agglomerates
larger particles of material made up of small, independent pieces.
Amides
linear or ring compounds with a CO-NH2 attachment. Common in surfactants.
Bacterial Remediation
liquefaction or break down of oily waste or clean-up of oil spills by the use of the naturally occurring oil consuming bacteria, chiefly ultramonis and pseudomonis.
Fluid Packed
liquid filled.
Fragmental Source Sedimentary (rock)
lithification of rock fragments.
Exfoliation Corrosion
localized and subsurface corrosion in zones often parallel to the surface that result in leaving thin layers of uncorroded metal resembling the pages of a book.
Body Lock Rig
locks slips, mandrels or cones in place in a downhole tool.
Carbon Sequestration
long term storage of carbon dioxide under ground.
Cavings
loose formation materials that falls into the wellbore.
Extraction Loss (produced fluids)
loss of volume due to removal of gasses or liquids during processing.
Circulation Losses
losses for any reason while circulating the well.
Acid Brittleness
low ductility of a metal due to its adsorption of hydrogen. More commonly called hydrogen embrittlement.
Fisheyes
lumps of undispersed polymer in suspension in the pill.
Barge
marine vessel without its own propulsion.
Flag
marking the pipe or wireline with a paint stripe.
Filtrate Reducers
materials that reduce the fluid loss from a wellbore fluid. May include Bentonite clays, lignite, CMC, etc.
DHTV
may be either downhole TV camera or a televiewer (a sonic caliper tool).
Driller's Depth
measured depth or the length of the pipe from top to depth.
Continuity
measurement of a formation being present over a large area.
Deep Investigation
measurement of formation properties far enough from the wellbore to minimize the effects of the invaded zone.
Ball Operated
mechanical device activated by pumping a ball of a certain size down the tubing in the injected or circulated fluid.
Amphoteric Metal
metal that may corroded in either acids or alkalines.
Batch Mixing
mixing a specific volume of a treating fluid in a properly sized tank - as opposed to mixing-on-the-fly.
Casing Head Gas and Gasoline
natural gas condensate, usually C2 to C8+. The C5-C8 components condense to a very volatile liquid when the temperature decreases near the wellhead.
Coal Bed Methane
natural gas formed during the coalification process and trapped within and adsorbed to the coal.
Conventional Gas
natural gas in a normal media, capable of flowing without other influences.
Drip Gas
natural gasoline or low carbon chain liquids, condensed from the rich gas from a well.
Drip Oil
natural gasoline or low carbon chain liquids, condensed from the rich gas from a well.
Activation Logging
near formation area is irradiated with neutrons that transform some nuclei into isotopes. The isotopes produced can be detected by radioactive energy levels and decay time. The original elements can be described from this behavior.
Blind Nipple
nipple that can be blocked off from formation pressure and give a false pressure measurement.
Adiabatic
no exchange of heat with the surroundings.
Dynamic Flow
non steady state flow or flow with changing conditions.
Elastic
non-permanent structural deformation during which the amount of deformation (strain) is proportional to the applied stress (load).
Fracture Effective Length
normally the propped part of the fracture that will support improved flow.
Empirical
observed response, often well proven by experiences but not theoretically derived.
Blinding (screen)
obstructing an aperture or opening by particles or debris.
Event (Risk)
occurrence of a particular set of circumstances.
Deep Marine Chalks
often massive deposits of coccolith fragments. Usually very high porosity and limited permeability unless fractured.
Clean Oil
oil with less than 1% water. Usually within pipeline spec.
Conventional Energy Sources
oil, gas, coal. The source of the energy may also have bearing on the definition. Unconventional hydrocarbon energy sources include shale oil (both mature and immature), shale gas, and tight gas (ultra low permeability, usually less than 0.001 millidarcy).
Chemical Flooding
one of several methods involving injecting a chemical into a formation to improve the production of hydrocarbon. May be from an injection well to a production well or injection into a producer with a soak period before recovery.
Artificial Lift
one of several methods that provide pressure assistance to increase flow from a well. The most common systems lighten (decrease density) of the flowing fluid (gas lift), or remove all or part of the liquid head from the reservoir (beam and electric submersible pumps).
Chrome Tubing
one of several steel compositions for tubing that uses chromium for increased resistance to CO2.
Casing
one of several strings of steel pipe in a well design that, together with cement, forms a barrier to fluid movement along the drilled hole. It is commonly at least partly cemented in the wellbore.
Explosive Fracturing
one of several techniques used to break the rock in the near well area. It was an early stimulation method. Fractures formed in this method are short. Although still used, its best application is in perf breakdown and overcoming some near well damage.
Carbon 14 isotope
one of three naturally occurring isotopes of carbon. The half life of the C14 isotope makes it idea for determining the difference between thermogenic methane (C14 absent) and biogenic gas.
Cable
one of various braided cables, with or without isolated conductance wires, used for well operations.
Enhanced Oil Recovery
one or more of a variety of processes that seek to improve recovery of hydrocarbon from a reservoir after the primary production phase.
Field
one or more reservoirs grouped by or related to the same general geologic structural feature or stratagraphic condition.
Concentric Tubing
one string inside another.
Complex Fracturing
opening up secondary natural fractures that may be orthogonal to the planar fracture. Also - networked fractures and shear fracturing.
Confirmation Well
or delineation well; a secondary well, after a field discovery well, drilled to help determine field extent, volume or potential rate.
Fluid Pound
or rod pound - a beam lift term where the pump is filled with gas from pump-off or too fast of an operating speed (rod speed).
Consequence (Risk)
outcome of an event.
Economic Interest
ownership of part of the well.
Anodizing
oxide coating of a metal surface to reduce corrosion.
Critical Components
part identified in a system that need a higher degree of reliability or traceability.
Flushed Zone
part of the rock that has been flushed with a sweep fluid. The area may have little hydrocarbons remaining.
Abrasive
particles propelled at a velocity sufficient to cause cleaning or wearing away of a surface.
Absolute Permeability
permeability to a single phase fluid in a cleaned core.
Conventional Crude Oil
petroleum in liquid form capable of flowing naturally.
Dope
pipe thread dope used to lubricate and seal the threaded connection.
Casing Tongs
pipe tongs used to make connections.
Accommodation
place where personnel spend their off-duty time on a rig.
Contaminant (cementing)
placing a material in a cement slurry (usually already in a wellbore) that purposely prevents the cement form setting so that it can be circulated out of the wellbore.
Baffles
plates in a separator on which the flow impinges and breaks out gas.
Anodic Protection
polarization to a higher oxidizing potential to achieve a reduced corrosion rate (promotes passivity).
Conglomerate
poorly sorted collection of sediments, generally formed in a very high energy environment. Similar to sandstones but have much larger grains (pebbles grade 4 to 64 mm). The space between the grains may be partly or completely filled with sand grains.
Corrosion Potential (Ecorr)
potential of a corroding surface in an electrolyte relative to a reference electrode under open-circuit conditions.
Cataclastic Rock
powdered rock created by crushing and shearing of tectonic movements.
Alarm Point
preset value of a monitored parameter at which an alarm is actuated to warn of a condition that requires corrective action.
Casing Pressure
pressure (intended or not) that occurs on the various outside annuli.
Capillary pressure
pressure differential between two immiscible fluid phases occupying the same pores caused by interfacial tension between the two phases that must be overcome to initiate flow.
Annular Pressure
pressure in an annular area. May be a vented or trapped annuli.
Bar (pressure)
pressure in atmospheres, approx 14.7 psia.
Choke Trim
pressure-controlling choke components, usually replaceable, expendable pieces.
Flexing
pressuring and depressuring the tubing (ballooning) to remove plugs or knock scale and other debris loose from the tubing wall.
Anion Exchange
process where a special resin exchanges chloride or hydroxide for contaminant anions such as fluoride, nitrate, sulfate and bicarbonate. Water purification is the primary use.
Cogeneration
production of electrical or mechanical energy and heat or other power.
Cumulative Production
production of hydrocarbon to date.
Domestic production
production originating inside a specific country of reference.
Erosion
progressive loss of material from a solid surface due to mechanical interaction between that surface and a fluid, a multicomponent fluid or solid particles carried within the fluid (NACE).
BVI (logging)
proportion of capillary bound fluids occupying effective porosity.
FFI (logging)
proportion of moveable fluids occupying the effective porosity.
Cation Exchange Capacity
related to concentration of cations on negatively charged clay surfaces that, when brine is present, can be exchanged/satisfied for/by cations in the brine. The total of exchangeable cations that a porous medium can absorb, expressed in moles of ion charge per kilogram of clay or mineral.
Depositional Energy
relating to the energy of the transport mechanism that carries particles into an area of deposition. Low energy environments may contain large quantities of fines where high energy environments are usually marked by larger and more consistent grain sizes.
Expectancy
remaining life.
Bioaugmentation
remediation technique that introduces natural hydrocarbon digesting bacteria and materials such as enzymes to remove hydrocarbons from soil, water or even air.
Bioventing
remediation technique that provides air to increase bacterial growth.
Air Stripping
remediation technique to strip volitile contaminants from contaminated ground water after a spill. Works to oxidize components and to activate bacteria that can digest hydrocarbons.
Downhole Separation
removal of a part of the water downhole followed by injection of the water into a disposal zone.
Deliquification
removal of condensed or produced fluids from a low rate gas well.
Cleanout
removal of fluids or solids from a well, usually by circulating.
Decommision
remove from service.
Bail
remove solids or fluids from a well.
Contracted Reserves
reserves of hydrocarbon dedicated to fill a specific contract.
Flood Plain
reservoirs that occur along ancient rivers where the rivers overflowed. Deposits are mostly silt and mud.
Drag (pipe movement)
resistance to linear motion.
Apparent Resistivity
resistivity recording where the measured value differs from the true or defined state by the influence of the mud column, invasion of a zone by fluids, or wellbore anomalies.
Back Flow
return flow from injection of a fluid into a formation.
Back Scuddling
reverse circulating.
Back Flushing
reverse flow of a fluid, usually in a well treatment or injection well, where flow from the reservoir to the wellbore, often at high drawdown, is used to clean fluids and shallow particulate damage from the near-wellbore area.
Asphalt or Asphaltene
ring compound materials in the oil composed of carbon, hydrogen, sulfur, nickel and other trace materials. Asphaltenes are mostly very small platelets (35 A) suspended by micelles of maltenes and resins and carried through the oil. They precipitate by agglomeration as the micelles break apart on shear, mixing with acids, or other interruption of the micelle stability.
Allogenic
rock constituents and minerals derived elsewhere from older formations and redeposited.
Cavings Rock
rock fragments that spall or break off the wellbore walls. Usually found as fill in the hole.
Argillaceous
rocks or substances composed of clay minerals, less than 0.625mm, or having a high proportion of clay in their composition such as shale
Biogenic Source (sedimentary rocks)
rocks such as coal resulting from decomposition of animal or plant deposition.
Bump Down
rod string stoke too long and hitting the bottom of the pump.
Casing Rotation
rotating the casing string during primary cementing to remove mud and improve primary cement bonding and isolation.
Cycle Time (drilling)
round trip time for a circulated fluid.
Bedding Plane
surface separating layers in a sandstone. Usually bedding planes mark the transition of the particle transport event. An accumulation of minerals or other materials laid down at the time of rock deposition or generated by reworking, that may create significant vertical permeability barriers in a sedimentary rock.
Absolute Temperature
temperature measurement starting at absolute zero (total absence of heat).
Closed Chamber Testing
testing the well into a chamber open at the bottom, but closed at the surface. Fluid entering the wellbore is equal to the fluid production minus the gas volume charge. A material balance approach.
Effective Shot Density
that number of the perforations that are open and flowing.
Dead Line (lift systems)
that part of a wireline or cable that is attached to a fixed anchor point and does not move through a pulley or other mechanical device.
Control Gas
that part of the gas stream used to actuate or operate equipment (may be rendered unusable for sale due to pressure drop, etc.).
Balance Point
that point at which forces acting on pipe in a well (usually while running) are equal.
Degrees API
the API gravity.
Coiled Tubing Unit
the CT, reel, injector head, power pack, control unit and pressure control equipment used in a coiled tubing job.
D/t (pipe)
the OD to the pipe wall thickness.
Dilatancy (rock)
the ability of a rock to expand through micro-fractures in consolidated rocks or grain position shifts in unconsolidated rocks.
Absorption (processing)
the ability of one material to absorb another.
Formation Integrity
the ability to resist breakup. Often taken as the fracturing point.
Chemical Resistance
the ability to resist chemical attack.
Clay Swelling
the absorption and modification of the clay matrix by a reactive water.
Filter Cake Lift-Off
the act of lifting off part of the mud filter cake, at the most permeable sections of the rock, in response to flow produced by draw down.
Accretion
the action of particles forming adhering clumps on pipe.
Drilling
the action of placing a hole to a depth and location.
Burst Rating
the actual minimum burst pressure derated by a safety factor. The derated burst is used as a maximum when pumping.
Excess Cement
the amount of cement over that required to cement the zone. Usually between 30% and 100% depending on hole diameter unknowns and contamination risk.
Deflection (drilling)
the amount of flex exhibited by the drill string.
British Thermal Unit or BTU
the amount of heat input required to raise the temperature of one pound of water by 1oF at water's maximum density at 39oF. It is approximately equal to 1 kilojoule.
Available Overpull
the amount of unused pull capacity of a rig after picking up the entire string weight.
Buoyancy
the amount of weight that is offset by lift from the fluid when the piece of equipment is immersed in the fluid.
Formation Evaluation
the analysis of formation character or properties, usually by remote logs.
Contact Angle
the angle of intersection of two fluids on a given surface. Describes wetting and non-wetting behaviors.
Build Angle
the angle of the inclination in the kickoff section when describing a deviated well.
Dip
the angle that the structural surface or bedding plane or fault surface makes with the horizontal. Measured perpendicular to the strike and in the vertical plane.
Back-Side
the annulus above the packer.
Bit Weight (drilling)
the applied downhole axial force component from the string weight.
Casing Point
the depth at which a casing string is set, either by design or because the mud can no longer control the pressure of the next deeper zone without adding weighting agents that would break down upper intervals.
Contact
the depth of the interface between the oil and water, oil and gas, or water and gas.
Corrosion
the deteriorating chemical reaction of a metal with the fluids with which it is in contact.
Angle of Repose (sand in pipe)
the deviation angle (from vertical) at which a solid material will no longer fall down the pipe, but will begin to accumulate on the pipe wall. The angle of repose for dry, round sand is about 62o and for wet sand about 50o to 60o depending on size, shape and moisture.
Boycott Settling Range
the deviation between 30o and 60o where refluxing (dropout and reverse flow) of particles and heavier liquid occurs in a lower rate well. The area in which gas bubbles may rise through fluid at 4 to 7 times that in a vertical well.
Blender
the device that takes in fluid feed, mixes in sand and then outputs to the pump truck.
Core Diameter (coiled tubing reel)
the diameter of the core of the CT reel.
Drawdown
the difference between two pressures. Completion drawdown is the pressure differential from the formation near the wellbore to the wellbore.
Differential Pressure
the difference in pressure between upstream and downstream of a measurement point.
Down Dip
the direction going down the tilt angle of the formation.
Displacement (horizontal well)
the distance between the wellhead and the top of a vertical line from the bottom hole location to the wellhead elevation at the surface.
Departure
the distance from the kelly bushing horizontally to the end of the well.
Fluid Invasion
the distance outward from the wellbore to the leading edge of the lost fluids. Varies with the permeability of the zone.
Borehole
the drilled hole.
Flush Production
the early, higher rate production that comes from the larger pores, fractures and vugs that empty quickly. Delivers a small, high rate flow every time the well is shut-in (recharges) and is brought back on line.
Fracture Closure Pressure
the earth stresses acting to try to close a hydraulic fracture offset by the pore pressure. A measurement of the pressure at which the fractured formation closes. Generally determined by the change in slope of the pressure reading as leakoff gradually lessens the volume of fluid that is holding the fracture open, until the fracture walls meet and the pressure reverts to a decline to pore pressure.
Equivalent Circulating Density
the effective fluid density that the formation sees when the friction pressure on the fluids returning to surface is added to the fluid density.
Base Management
the efficient delivery of proved developed reserves through excellence in Reservoir, Well and System management.
Bernoulli's Equation
the equation is used in the design of chokes and explains the manner in which pressure in the body in the body of the choke, downstream of the first pressure drop, is lower than the eventual recovery pressure at the end of the choke.
Drilling Rig
the equipment at the surface used to lift and run the drilling string, provide the rotation and pump fluids down the string.
Bottom Hole Assembly or BHA
the equipment or tools at the bottom of the tubing or drill string. The BHA is changed to achieve a certain result.
Continuous Phase
the external phase in an emulsion.
Box
the female part of the connection.
Cloud Point (Paraffin)
the first appearance of microsized paraffin crystals in suspension in the oil.
Bed Rock
the first solid rock under loose sediments.
Conductor Pipe
the first string of casing run, usually to keep rocks or dirt out of the wellbore. It is usually not cemented in place. It may be jetted in, driven in, drilled in or installed in an excavated hole.
Area Open To Flow
the flow area generated by perforations across a zone of interest. Typical calculated perforation entrance hole areas are 1% to 6% of the pipe body. Used in pressure drop calculations.
Flow Line
the flow connection from the wellhead to the separation facility, pipeline or storage unit.
Filter Cake Lift-Off Pressure (drilling)
the inward differential pressure difference that will result in part of the filter cake being removed from the face of the formation (usually over the most permeable and higher pressured sections).
Filter Cake
the layer of solids stranded on the face of permeable formations by liquids driven into the rock by pressure differential towards the formation. When sized correctly the filter cake may completely stop losses.
Fracture Half Length
the length of one wind of a fracture from the wellbore to the tip.
Bond
the level of adherence of one substance to another.
Filtrate
the liquid that leaks off into the formation during fluid loss.
Fracture Proppant Pack Density
the loading of proppant per square foot after the fracture has been placed. Commonly between 4 and 16 lb/ft2 of fracture face.
Explosive Limits
the low and high range (wt %) of a combustible gas mixed in air that can be ignited at ambient pressure and temperature.
Detectable Limit
the lower limit of analysis for a test of a piece of equipment for a specified measurement.
Brake (drilling)
the main device for stopping the travel of the drawworks of a rig when running or pulling a drill string.
Density
the mass per volume of a substance. Density of fresh water is 8.33 pounds per gallon or 1 gram/cc.
Cementation
the material in the rock between the grains that binds the grains together.
Filter Media
the material used to make up a filter bed. Common filter media are DE, sand, various fibers, etc.
Burner Capacity or Rating (flare)
the maximum BTU's that can be released from a burner while burning with a stable flame and satisfactory combustion.
Critical Flow Rate (corrosion/erosion)
the maximum flow rate that avoids damage to the pipe from corrosion or erosion.
Critical Flow Rate (sand production)
the maximum flow rate that avoids producing sand from the formation.
Completion Technical Limits
the maximum production or flow capacity possible by the best completion attainable.
Absolute Open Flow (AOF)
the maximum rate that a well can produce at the lowest possible bottom hole pressure.
Allowable Working Pressure or Stress
the maximum stress allowed by code or other agreement or study as a fraction of test pressure. Design pressure of the system is related to hoop stress.
Endurance Limit
the maximum stress that a material can withstand for an infinitely large number of cycles (NACE).
Fatigue Strength
the maximum stress that can be sustained for a specified number of cycles without failure.
Absolute Viscosity
the measure of a fluid's ability to resist flow without regards to its density. It is defined as a fluid's kinematic viscosity multiplied by its density.
Annulus Sea Assembly
the mechanism that provides pressure isolation between each casing hanger and the wellhead housing.
Critical Flow Rate (biofilm)
the minimum flow rate that keeps biofilm deposits from forming on the surface of the pipe.
Critical Flow Rate (liquids unloading)
the minimum flow rate to produce liquids from a well.
Drift (pipe gauge)
the minimum id of tubing through which a standard drift tool will pass.
Basalt
the most common volcanic rock. Usually fine grained.
Anthracite
the most highly metamorphosed form of coal.
Bit Whirl (drilling)
the motion that a bit makes when it does not rotate about its center. This may manifest itself in out of round holes and severe bit damage. Generally a poor drilling performance.
Coning
the movement of a water upwards or gas downwards towards a decrease in pressure caused by producing hydrocarbons in a zone with no vertical permeability boundaries.
Connate water
the natural brine occupying the pore spaces. Usually this water is at equilibrium with the minerals in the formation.
Associated Gas
the natural gas which occurs with crude oil. It may be free or dissolved. When it occurs as free gas, it may be called unassociated gas.
Fracture Extension Pressure
the pressure necessary to extend the fracture once initiated. The fracture extension pressure may rise slightly with increasing fracture length and/or height because of friction pressure drop down the length of the fracture. Fracture roughness, fracture width and fluid viscosity also have influence on extension pressure.
Fracture Initiation Pressure
the pressure necessary to start a fracture from the wellbore.
Fracture Breakdown Pressure
the pressure needed to initiate a fracture.
Formation Pressure
the pressure of the fluid in the formation. The initial reservoir pressure is the pressure at discovery.
Eon
the primary division of geologic time - from oldest to youngest: the Haldean, Archean, Proterozoic, and Phanerozoic.
Depletion Plan
the primary process for Life of Field resource management. The Depletion plan sets out the framework of how Resource Management underpins efficient exploration of the resource.
Float Valve
the primary, bottom hole valve in the float collar or shoe that allow the casing to self fill while running and allows the cement to pass into the annulus but helps prevent cementing U-tubing after the job. Drillable and subject to erosion wear.
Effective Stress (fracturing)
the principle stress less the fluid pressure.
Allocation
the process of determining ownership of hydrocarbons delivered to the meter or LACT unit on a lease.
Diagenesis
the process of forming a sedimentary rock from the clastic grains. May also be in conjunction with several geochemical processes such as cementation reactions and chemical dissolution.
Fractionation
the process of separating natural gas into component parts or fractions such as propane, butane, ethane, etc.
Allowable
the production limit set on a specific well by a government regulatory body. Rarely seen.
Drift Diameter
the published drift diameter for a pipe that describes the diameter of a tool that can pass through the pipe when the pipe is vertical (no doglegs).
Background Radiation
the radiation intensity existing in the environment before a specific radiation source is considered.
Diffusion
the random scattering of particles due to kinetic energy of the particles. Affected by viscosity, density and temperature.
Combustible Limits (fuel gas)
the range of gas concentration in air where the fuel gas or combustible gas will ignite.
Adsorption Band (seismic)
the range of wavelength energy that can be adsorbed by a given formation.
Decay Rate
the rate at which a population of radioactive atoms decays into stable daughter atoms. Rate expressed in half-life of the parent isotope.
Build Ramp
the rate of increase of the deviation of a well.
Fluid Loss
the rate of loss of liquids to the formations from the fluid being circulated through the wellbore.
Closing Ratio
the ratio between the pressure in the hole and the operating-piston pressure needed to close the rams on a given BOP design against a particular well head pressure.
Compression Ratio
the ratio of the absolute outlet pressure of a compressor to the absolute inlet pressure.
Absorptance (seismic)
the ratio of the energy absorbed by a formation in relationship to the total energy passing through it.
Anode Corrosion Efficiency
the ratio of the mass loss of actual corrosion of an anode to the theoretical corrosion mass loss calculated from the quantity of electricity that has passed between the anode and the cathode using Faraday's law (from NACE).
Carbon/Hydrogen Ratio
the ratio, either on a weight or on a molecular basis, of carbon-to-hydrogen in a hydrocarbon material. Materials with a high carbon/hydrogen ratio (e.g., coal) are solid. The ratio is useful as a preliminary indication of the hydrogen quantity needed to convert the hydrocarbon to a gas and/or liquid (AGA).
Acquisition Log
the raw, real time recording of the data, later formed into a digital or playback log.
Absolute Pressure
the reading of gauge pressure plus the atmospheric pressure.
Conductance
the reciprocal of resistance in direct current logging measurements. Measured in siemens (formerly mhos).
Down Stroke
the recovery stoke downward on a beam pump where the pump is filling with fluid by pushing the open traveling valve through the standing fluid.
API Gravity
the relative density of a hydrocarbon based on a scale of degrees API. Density in g/cc = (141 / (131 +API)).
Desorption
the release of materials that have been absorbed or adsorbed in or onto a formation.
Effective Wellbore Radius
the theoretical radius of a wellbore that would flow the same rate as a wellbore with a fracture. Effective wellbore radius is a comparison of flow improvement related back to physical radius.
Feet of pay
the thickness of a pay zone or formation, usually the gross (total) thickness.
Casing Coupling
the threaded connection, almost always upset to the outside.
Cement Pump Time
the time after mixing of the cement slurry before the cement becomes so viscous that it cannot be pumped.
Back-Up Wrench or Tong
the tool that keeps the pipe string from rotating while a joint is made up.
Fishing Tools
the tools that can capture a lost item (a fish) in a well.
Crest (geology)
the top of a pay structure.
Crest (flow)
the top of the water cone in (usually) a horizontal well. Compare with coning in a vertical well.
Deflection
the total change in angle of a wellbore in a given distance.
Dry Gloss Heating Value (reactions)
the total energy transferred as heat in an ideal combustion reaction at standard temperature and pressure in which all water formed appears as a liquid.
Acoustic Travel Time
the total time required for an acoustic wave to travel through a substance.
Downstream
the transport, refining and product making part of the oil business.
Cold Treating
the treating of an emulsion with chemicals to break an emulsion without resorting to the application of heat.
Box Threads
the treats in the box or female connection.
Cycle Time (plunger)
the trip time for a plunger from dropping to recovery.
API Unit
the unit of radioactivity used for natural gamma-ray logs.
Aperture
the unobstructed opening size (diameter, length and width, or other shape factor).
Elastic Limit
the upper range of elasticity, just before the body is permanently deformed.
Annular Valve
the valve on the side of the tree that controls access to the annulus.
Acoustic Impedance
the velocity of an imposed sound wave (acoustic velocity) through a rock times the density of the rock.
Annular Velocity
the velocity of fluids flowing in the annulus. Important in clean-up and displacement processes.
Dip Slip Fault
the vertical displacement of a fault along the dip plane.
Apparent Viscosity
the viscosity at a given shear rate and a given temperature.
Dynamic Viscosity (produced fluid)
the viscosity of the fluid in the reservoir at the reservoir conditions. Note - associated gas reduces the viscosity of most oils.
Absolute Volume
the volume a solid occupies when added to a fluid divided by its weight. m3/kg or gal/lb.
Compressibility
the volume change of a material when pressure is applied.
Displacement (volume)
the volume of a wellbore occupied by fluid. When the swept volume varies from the calculated displacement, part of the wellbore may not be actively swept.
Absorption Oil (facilities)
the wash oil used to remove heavier hydrocarbons from the gas stream.
Astenosphere
the weak section of soft rock in the upper mantle just below the lithosphere. It is involved in plate movement. Depth is 70 to 100 km below the surface.
Air Weight
the weight of a string in air without the effect of buoyancy provided by wellbore fluids.
Buoyed Weight
the weight of a string or piece of equipment immersed in the wellbore fluid. It is strongly dependent of the density of the wellbore fluid.
Expected Value (Risk)
the weighted average using probabilities as weights. For decisions involving uncertainty, the concept of expected value provides a rational means for selecting the best course of action and for forcasting portfolio level performance.
Flash (pipe)
the weld seam on or in a welded pipe.
Fracture Width
the width of a fracture at the wellbore. Hydraulic frac width is generated by frac fluid viscosity and/or pump rate (i.e., horsepower).
Bridle (beam lift)
the wire rope attachment of the horses head to the polish rod on a beam lift pump jack.
Drilling Line
the wire rope used to position tools on the floor. Also used to describe the wire rope on a cable tool rig.
Conveyance (well work)
the wireline, slickline, tubing or coiled tubing used to convey tools or equipment in a well.
Flow Tubes
tubes with a diameter slightly larger than the braded wireline or slick line that are used in the "stuffing box" on a wireline intervention to isolate the well pressure and fluid from the atmosphere. They work in combination with oil or wireline grease injection to form a hydraulic seal.
Doubles (pipe)
two joints screwed together.
Cross Plot
two or more log responses or other variable records plotted on an X-, Y- axis.
Dual completion
two pay zones in the same well that produce up independent flow paths in the same well.
Double Block and Bleed
two successive plugs, each capable of holding maximum pressure, with a vent between them capable of bleeding off all pressure between the plugs. Also - a valve with two seating surfaces which, in the closed position, blocks flow from both valve ends when the cavity between the seating surfaces is vented through a bleed connection on the body cavity.
Casing Joint
typically a length of casing with a connection on each end. Length may vary from less than 30 ft (9 m) to about 40 ft (12 m).
Electrical Log
typically a resistivity log.
Abandon
typically means to cease efforts, either temporarily or permanently, to produce a well. Abandon may have a legal meaning in some locations.
Cement (completions)
typically the Portland, silicate, and/or pozzilin, etc., mixtures used to form a stone-like permanent seal between the pipe and the formation.
Drill Stem
typically, rotating components in a drill string.
Alluvium
unconsolidated to well sorted to poorly sorted (gravel to sand sized) particles transported by water.
Basement Rocks
unproductive rocks, usually igneous or metamorphic, at the bottom of a sedimentary rock sequence.
Break-out
unscrewing a joint of pipe of part of a BHA.
Back Off
unscrewing a tool or equipment. In pipe recovery, back-off of a joint precedes recovery of the upper section in a well. Common in plug and abandonment or sidetrack operations.
Anomalous
unusual data or measurement that is away from or out of the range of other data.
Acidizing
use of a mineral acid (typically HCl or HCl/HF) or an organic acid (typically acetic or formic) to remove damage or stimulate the permeability of a formation.
Casing Inspection Log
uses eddy currents in a magnetic field to estimate casing thickness and anomalies.
Annular Flow
using the annulus as the flow path.
Chemical Tracing
using water soluble chemicals to track the flow channels in the reservoir.
Burning Shoe
usually a flat bottom mill.
Filter Press
usually at DE filter.
Ceramic (frac)
usually ceramic (man- made) proppant.
Coal Gas
usually methane which is adsorbed and absorbed to the high surface area of the coal.
Drilling Platform
usually offshore; a platform from which wells can be drilled. It may be permanent (with legs grouted into the seafloor to depths of several hundred feet), anchored or dynamically positioned.
Back Wash
usually reverse circulation
Ferrous Iron
valence state +2 iron in solution. In oil field operations, most solution iron is ferrous until oxygen is encountered. Precipitates at iron hydroxide when the pH exceeds 7 or when oxidized to ferric by contact with oxygen.
Ferric Iron
valence state +3 iron in solution. A very common catalyst in oil field emulsion and sludge formation. Precipitates at iron hydroxide when the pH exceeds 1.8 to 2.2 (depending on sour conditions).
Bi-Directional Valve
valve designed for blocking the fluid in upstream and downstream directions.
Circulation Control Valve
valve normally placed across the circulation point to allow isolation of the tubing strings or tubing/casing during production.
Block Valve
valve that blocks flow into the downstream conduit when in the closed position.
Flashing
vaporization of water or light ends as pressure is released during production or processing.
Commercial Production Level
varies with the well - an indicator of the minimum flow rate and type of fluids that can justify completing or continuing to operate the well.
Dump Flood
various - usually allowing water to gravity feed into the annulus (without packer) or the tubing and into the formation.
Double Board
working platform for the derrickman on a drilling rig.
Casing Tongs
wrenches specifically made for making up casing joints.
Absolute Zero
zero point on the absolute temperature scale; equal to -273.16 degrees C, or 0 degrees K (Kelvin), or -459.69 degrees F, or 0 degrees R (Rankine).
