Ocean Resources Midterm Study Guide
What kinds of deposits are being found and exploited (what kind of crude oil)?
"Heavy oil," which is dirty, more difficult to extract, and has a higher viscosity was found in the Kraken Field. Not as ideal as light sweet crude, because requires more refinery.
What are three things about government regulation of offshore drilling today that are different because of the Deepwater Horizon blowout and spill? (we will go over this in class)
- Had to have a clean-up vessel and containment supplies nearby. - Upgraded standards for casing, cementing, BOP. - Mineral management service was divided into two departments in order to make sure regulations are better enforced.
What are some potential problems with mining manganese nodules on the seafloor?
- Since only small areas have been investigated, it is hard to say to what extent the deep-sea ecosystem would be impacted. - Marine biologists insist that mining has to be regulated because of the extent in which it would impact the protection of endemic (native) species. - Biologists insist that a successful recolonization for these various animal species such is possible.
What are some potential problems with: A. the technology and physical process of mining the seafloor B. the seafloor and oceanic environment resulting from seafloor mining?
- Though they have a mining tool, it remains untested. - In addition, many believe that mining one site may not make that big of a difference, but the physical and intensive impact of mining a region over and over again could prove disastrous for the ecosystem. - Damages marine life in ecosystem. - Seafloor mining could kill organisms at the vents. - Potentially toxic metals entering the water and sediment through boats, barges and other heavy equipment could lead to turbidity.
What are three processes that form a metal sulfide deposit?
1. Black smoker chimneys grow upward. 2. Metal sulifdes replace underlying lava. 3. Cooling and mixing of hot, hydrothermal fluid mixes with cold seawater cause metals to precipate as metal sulfides.
The TAG metal sulfide deposit is 3 million metric tons, and contains 5% Copper. How much is this deposit worth? (you need to look up the price of copper per kilogram)
1.05x10^10 pounds (when the conversion rate is 3.90 pounds per kilogram)
Read Hannington-11hydrothermal pdf in Canvas/Files/MOR Hydrothermal folder. This gives estimates of the distribution of seafloor metal sulfide deposits, and how much metal is in in these deposits at mid-ocean ridges. You can find answers to the questions below in this article. As with the others, print out the answers and bring to next class. 1. In total, how much metal is present on the seafloor in metal sulfide deposits? How much of this is Copper plus Zinc? Assuming all this copper + zinc is copper, how much is this worth? (note that tonne is a metric ton = 1000 kilograms) you will need to look up how much copper is worth per kilogram, then calculate the total value of this.
6x10^8 tonnes of metal sulfide deposits. About 3x10^7 tonnes of copper and zinc. 1.68x10^12 pounds is how much the metal sulfide deposit is worth. 8.4x10^10 pounds is how much the copper wire is worth.
What is a blow-out preventer: what does it do and how does it work? Why is this necessary?
A blow-out preventer has internal "Rams" that crimp or sever the drill pipe in order to prevent blowouts, which is the uncontrolled flow of gas and oil moving up through the pipe. Several blow-out preventers are also put in "stacks" on the seafloor.
What are two main ways that active and passive continental margins differ?
Active margins are a plate boundary and are tectonically active, while passive margins are not a plate boundary and are not tectonically active. Continental shelf, slope, rise are on passive margins, while trench is on active margins.
What percentage of US oil production comes from offshore on the US Gulf Coast? (in the "Production" section of the Wikipedia Gulf of Mexico text)
Approximately 1.5 million barrels of oil a day and 15% of all US oil production comes from the Gulf Coast. Total global oil production= 90 billion barrels a day.
What controls the overall depth of the ocean basins?
As the ocean lithosphere ages, it begins to cool, thermally contract, and sink. This causes the ocean lithosphere to become more dense and the over depth of the ocean basins to get deeper as a result.
What are two ways BP tried to stop the leak?
BP tried to use a "containment vessel," which is a big box that is used to contain and capture oil flow formed from gas hydrates. However, this didn't work. In addition, BP tried "Top Kill" which is the adding of heavy mud to plug the well.
Who was at fault, the oil companies or the government?
Both were at fault. BP was obviously at fault for being the company in charge of the operation and since the spill happened under their watch. However, the government was also at fault for not enforcing regulations and overseeing the operation.
What is the base of the food chain at hydrothermal vents on mid-ocean ridges? How could this be considered an ocean "resource"?
Chemosynthetic microbes. These microbes support other forms of life and are analogues for early life on Earth. They may also be similar to life on other planets. They are also enzymes for industry and compounds for medication.
What are some other organisms at hydrothermal vents? How are these related to bacteria?
Clams, crabs, and tubeworms. Tubeworms have a symbiotic relationship with the bacteria that live inside of them as they can't survive without each other. Tubeworms and bacteria serve as a food source for animals like crab, fish, and octopus.
What is the EEZ?
EEZ stands for exclusive economic zone and is a 200 nautical mile zone out in sea from the coast of each country. Each country owns all of the resources in that area and has special rights regarding the exploration and what they want to do with resources in their area.
What is the general trend of exploration and production with respect to the coast and water depth. (in the "History" section of the Wikipedia Gulf of Mexico text)
Exploration with respect to water depth has increased because of newer, more efficient technology. However, oil production peaked in 1975 but now is back on the rise because of fracking and new technology.
How far offshore does Federal control of oil and gas (and everything) go?
Federal control goes all the way out to the 200 mile Exclusive Economic Zone.
What are gas hydrates? Where do they occur?
Gas hydrates are ice-like compounds in which small gas molecules are trapped inside a cage of water molecules. They have a crystalline form and occur along continental margins and in the artic permafrost on continental tundra.
Are these types of back-arc basin metal sulfide deposit a resource anywhere else? What metals are sought and were do these occur (name a country/countries or region)
Gold, copper, and zinc in Abitibi Greenstone Belt, Canada and gold and copper in Kidd Mine, Ontario. Also Austrailia.
. What is present at the bottom of the Red Sea (page 91)? How and why does this deposit differ from metal deposits at mid-ocean ridges out in the open-ocean? Who is interested in mining metal deposits in the Red Sea, and why?
Huge ore deposits like those that occur in black smoker chimneys. Sudan and Saudi Arabia are interested in the Red Sea because of its richness in metals like copper, zinc, silver, and gold and because of a spike in ore prices. It is estimated that the total of seabed minerals in the Red Sea is about $8.21 billion.
What are the main features of submarine hydrothermal vent fluids? (i.e., what are the main ways these fluids differ in temperature and composition from seawater?)
Hydrothermal vent fluids can reach a temperature of around 365°C while the temperature of seawater is about 2°C. In terms of composition, hydrothermal vent fluids are much more acidic, enriched with metals, and have a much higher concentration of dissolved gases. Specifically, hydrothermal fluid contains no oxygen (mostly hydrogen sulfide H2S), while seawater contains oxygen (mostly sulfate SO4).
The TAG hydrothermal metal sulfide deposit has black smoker vents, but it also has "white smoker" vents, with different fluid compositions. What do these white smoker fluids and the presence of anhydrite (CaSO4) deep within the TAG sulfide mound tell us about processes within the mound?
Lower temperature white smoker vents tell us that cold seawater coming down mixes with hot hydrothermal vent fluid coming up, which precipitates metal sulfide and anhydrite within the mound. White smoker chimneys occur beneath the seafloor and are more acidic. Also, the lack of metal sulfides is why the smoke color is white.
What are manganese nodules?
Manganese nodules are the most important deposits of metals in the sea today. They contain mainly manganese, but also iron, nickel, titanium, and cobalt and are of such great interest because they contain great amounts of many metals that are found in today's economically minable deposits. Manganese nodules have very slow growth and a layered structure.
Where do they occur in the oceans? (What oceanic Province) How abundant are these?
Manganese nodules occur on abyssal plains. They are very abundant as these metal sulfide depostis contain great amounts of many metals such as manganese, iron, nickel, titanium, copper, and cobalt.
What valuable metals and other elements do they contain that are of interest as a resource?
Manganese, Iron, Nickel, Titanium, Copper, Cobalt, and rare earth metals.
What are the four main metals in hydrothermal vent fluids?
Manganese, iron, copper, and zinc.
How do metal sulfide deposits at back-arc spreading ridges differ from those at mid-ocean ridges? (What metals are present in higher concentrations than in deposits at mid-ocean ridges to make these deposits more valuable?)
Metal sulfide deposits at back-arc spreading have different rock types, rocks that are more metal rich, rocks that contain higher concentration of gold, and deposits that are closer to land/islands than those at mid-ocean ridges.
Where is it currently planned to mine massive sulfide deposits at an oceanic spreading center (in a back-arc basin)?
Mining in the Bismark Sea off of Papua New Guinea.
Has global production Peaked?
No, global production has not peaked. Over the last 50 years, it has steadily increased.
Are these being mined or extracted from the seafloor? Why or why not? What is going on with exploration for manganese nodules, and who is doing this?
No, they are not because there is no market ready mining machinery. However, Japan and South Korea have started to build prototypes that have been tested in the sea, but they still need improvement before mining can actually start. Many other countires like China, India, UK, and Germany continue to devote resources towards exploration for manganese nodules, but the machine still has to be adapted for water depths and working conditions on the high seas.
What are the relative proportions of oceans versus continents on the Earth's surface?
Oceans make up 70.8% of Earth's surface area, while land makes up 29.2% of Earth's surface area.
How does offshore oil affect "Peak Oil"?
Offshore oil production is increasing even as total production is decreasing. In addition, US offshore oil makes up 15% of all US oil/gas production.
How does North Sea production compare to the US Gulf Coast? (note boepd in the figure is barrels of oil per day)
Oil production in the North Sea and the US Gulf Coast are both 1.5 million barrels a day.
What are two major negative effects of the BP oil spill on ocean resources?
One major negative effects of the oil spill is on animals as it can lead to animal poisoning, hypothermia, drowning, reproduction issues, food source loss, and destroys the animal's environment. BP oil spill also significantly affected shorelines.
What events or problems caused the blowout on the Deepwater Horizon rig (BP, Gulf of Mexico)?
One of the main problems was human error. They were behind schedule and rushing so they had trouble with the cementing well, since they did not properly test the cement. In addition, the blowout preventer failed, causing gas to shoot up to the surface. Lastly, there was no clean-up vessel nearby to help in case of a spill.
Where are Brazils's new offshore oil and gas fields A. what ocean province? what kind of "trap"?
Outer Continental Shelf Trapped in pre-salt deposits.
Rivers bring dissolved material to the oceans. How do submarine hydrothermal systems influence the composition of the oceans in comparison to rivers? Which is more important?
Rivers balance hydrothermal reactions and serve as the principal channel in which most elements enter the ocean. Hydrothermal systems take out a lot of magnesium out of the ocean and help maintain the composition of the ocean. Both equally important.
How old is the TAG hydrothermal deposit? What does its cycle of activity and quiescence and the presence of breccias (broken rock cemented by different minerals) tell us about how the deposit formed?
Roughly 20,000 years old. Inactivity occurs when the magma chamber eventually cools off, causing all of the anhydrite to dissolve and collapse. The dissolution and deposition of anhydrite leads to breccias, which are rocks that are cemented together and have periods of activity and inactivity.
What are some features that make this specific site a good one for seafloor mining?
Solwara has big sulfide deposits and are well-mapped with lots of sampling cross section through sulfide deposits. In addition, Solwara has high gold and copper contents and has all the necessary processing equipment near land.
What are some arguments against Peak Oil?
Some arguments are that new oil deposit will be found, new technology will extract more oil from tar sands or permeability reservoirs, energy use will be more efficient, and other energy sources will be utilized or discovered such as wind, waves, and tides.
What is the "Proof" of seafloor spreading and continental drift?
Some evidence supporting continental drift are that the continents can be fit back together, the rock sequences across certain continents match up, there is glacial evidence, and there is evidence that fossils match up when the continents are put back together. However, though all four of these were evidence supporting the theory of continental drift, seafloor spreading served as the "proof" for continental drift and led to the concept of plate tectonics. Magnetic evidence serves as the "proof" for seafloor spreading. The Earth's magnetic field periodically reverses and symmetrical magnetic anomalies spread out across the mid-ocean ridge. These seafloor magnetic anomalies are evidence for seafloor spreading since they match the magnetic time scale and show that crust is progressively younger towards the middle of the ridge, proving that new ocean crust does in fact form at the mid-ocean ridge.
What three factors are needed to form gas hydrates?
Some factors that are needed are organic-carbon-rich sediments at continental margins, biogenic (bacterial) reactions in sediments, and the accumulation of methane gas hydrate when gas hydrate is stable (low-temperature, high pressure).
. What are some factors that determine how desirable different types of crude petroleum are?
Some factors that decide whether or not the crude is sweet or sour is high vs. low sulfur content and good vs. less good for refining. Light sweet crude is clean, already partly refined, and has a lower viscosity, meaning it is more "mature." On the other hand, sour crude is "dirty", requires more refining, and has a heavier viscosity.
What equipment is needed for offshore drilling: think of what is required between the ship and the seafloor, at the seafloor, and beneath the seafloor.
Some of the equipment needed is a drill pipe, a riser, BOP, casing, cement, and a drill pipe. Casing, cement, riser, and blowout preventer are used to control fluid (oil and gas).
What were some of the problems that Shell had with drilling in the Arctic?
Some of the problems Shell had was that the discoverer drillship went adrift on its way up to the Arctic, ice blocked access to drilling sites until much later in the season than normal, there were delays in obtaining Coast Guard certification for the oil spill containment vessel (The Arctic Challenger), and the containment dome for gathering any oil spilled during a blowout was damaged during testing.
What are some problems that are unique to drilling in the Arctic?
Some problems with drilling is that the Artic is inhospitable as there are long, cold winters, the Artic is covered with ice during the winters. The Artic is also envioronmentally sensitive, as it is difficult to clean up oil spills, is a short growing season meaning that it takes a long time for animals and plants to recover, and it affects local Inuit life and culture.
What are some technical problems with extracting this oil?
Some technical problems are that the oil is under a layer of salt, meaning that it is harder to extract and would require more robust, stronger equipment for extraction to work. Also, Brazil is lacking highly trained manpower, and efficient logistics.
How far offshore does state control of oil and gas go?
State control only goes out a few miles.
Besides hydrothermal vents, where else on mid-ocean ridges does microbial life (bacteria) occur?
Subsurface biosphere
What are three types or sources of oil spills?
Tankers, drilling rigs, and pipeline leaks
What is going on to help increase exploration in the North Sea?
Tax incentives have helped lead to the exploration and testing on the heavy oil Kraken accumulation in the northern part of the North Sea. The gross peak oil production in the Kraken field is estimated to be more than 50,000 barrels a day.
What is unique about the Arctic ocean that makes it desirable for offshore oil drilling (think where offshore oil deposits are)?
The Artic Oceans contain vast continental shelves, passive margins, and potentially vast oil and gas deposits.
At what type of mid-ocean ridge are the biggest metal sulfide deposits found (Fast-spreading or Slow-spreading?) Why do you think the biggest deposits are found here? (Shouldn't fast spreading ridges have bigger deposits since they have a greater magmatic budget, and it's the magma that is the heat source to drive hydrothermal circulation, right?) We will discuss this in class, as it may not be obvious, but try to come up with a reason for this.
The biggest metal sulfide deposits are found at the slow-spreading mid-ocean ridge, because at fast-spreading ridges, the magma supply is higher and the lava comes up so fast that it covers most of the metal sulfide deposits. However, since the magma supply of slow-spreading ridges is lower, there is not enough lava to cover up most of the metal-sulfide deposits, which is why there are bigger metal-sulfide deposits here.
What is the concept of "Peak Oil?
The concept is that global oil will reach a maximum production level and then start to decline. Consumption will eventually start to surpass production, leading to a fundamental change in world economies.
How do they form (2 main processes)?
The first process, hydrogenous growth, is when metal compounds dissolved in the water are precipitated. The second process, diagenetic growth, occurs when seawater that penetrates in the seafloor and mixes with the sediment becomes enriched with metal compounds.
How do black smoker chimneys grow? (you could divide this into 2 or 3 stages)
The first stage involves the mixing and heating of hot hydrothermal fluid with cold seawater leading to the formation of anhydrite. Then, the cooling and mixing with seawater causes metals to precipitate as metal sulfide minerals and the chimney is formed as a result of all of the metal sulfide precipitating.
What do you think is the future of Arctic offshore oil and gas in the Arctic?
The future of drilling in the Artic is in doubt. There have been many costly setbacks and Shell announced in 2013 that it would not return to the Artic. In addition, currently oil prices are too low to warrant the high cost of exploration and drilling in the Artic.
How does cold, basic seawater change into hydrothermal fluids? Starts in the recharge zone where seawater is heated by the magma chamber. The hot seawater starts to react with rocks and precipitates with magnesium, making the seawater a hot acid. The hot acid dissolves metal and sulfur from basement rocks in the reaction zone. The hot fluid then rises rapidly to the surface in the upflow zone. Specifically: A. What heats the fluid? B. What role does magnesium play in the composition of hydrothermal fluids? (what happens to magnesium, and how does this change the fluid?) C. How does the hydrothermal fluid get enriched in metals? (where do the metals come from?)
The magma chamber Magnesium combines with OH^- from the seawater. This removes OH^- from the solution and causes H^+ concentration in fluid to increase and thus makes the fluid more acidic. The hot acid dissolves metals like manganese, iron, copper, zinc, and alkali metals from basement rocks.
How will this mining be carried out? (what equipment will be used)
The mining system for Solwara is that there are seafloor remotely-operated excavators that serve as "grinders" on the seafloor. In addition, there is a riser system that will raise the crushed ore to the surface and onto the ship.
Besides supply and demand affecting the price of oil, A) How does Technology affect the supply and price of oil?
The new technology increases production which therefore causes the price to go down.
In 6A and 6C pdf readings, Cyprus (in the eastern Mediterranean) is mentioned: What is the origin of these rocks in Cyprus? Why do we care about them in a class on Ocean Resources?
The origin of these rocks in Cyprus are believed to be the structure of the oceanic crust that have been placed onto the continents by tectonic movements. These rocks are important because they contain metal sulfide deposits that are mined for copper.
What are the three main "zones" of fluid flow and reaction in submarine hydrothermal systems?
The recharge zone, the reaction zone, and the upflow zone.
What are six oceanic provinces? (be able to sketch these)
The six ocean provinces are Continental Shelf, Continental Slope, Continental Rise, Abyssal Plain, Mid-Ocean Ridge, and Trench.
What is the status of gas hydrates as an energy source? What kinds of projects are underway involving gas hydrate extraction or production?
The status is that it is hard to extract hydrates in mud, but there's a lot of gas hydrates in mud. However, it's easier to recover in sands, but there are less gas hydrates in sands. There are projects for the drilling of gas hydrates in the Arctic, Mallik Site, and US Gulf of Mexico.
What are the steps in drilling a well beneath the seafloor?
The steps are first you need to cement the casing (large diameter metal pipe) into hole, which stabilizes the hole. The casing keeps the drill fluids in and the formation fluids out. Lastly, the casing enables control of pressure in the well during drilling, and during production of oil and gas. The next step are the drill pipe operates inside the riser and keeps fluids in and seawater out. Lastly, the blowout preventer internally "Rams" in order to crimp or sever the drill pipe, which prevents fluids from moving up through the pipe.
What are the two main processes that control the differences in the overall shape (bathymetry, volcanism, etc) of fast-spreading (like the East Pacific Rise) and slow-spreading (like the Mid-Atlantic Ridge) mid-ocean ridges? Which of these process is associated with fast- and which with slow- spreading ridges?
The two main processes is that seafloor spreading and "inflated volcano" cross section is associated with fast-spreading ridges and faulting and "Grand Canyon" cross section is associated with slow-spreading ridges. Fast spreading ridges also have a greater magma budget and is associated with magmatism, while slow-spreading ridges are associated with tectonism.
Why should we be interested in these? Specifically: A. What is their contribution to energy resources, (how much carbon is stored in gas hydrates compared to other fossil fuels?) B. How can these affect the seafloor environment? C. How might gas hydrates affect climate change?
There are large amounts of organic carbon in gas hydrates, which could be a very valuable source of energy. Gas hydrates account for 22% of all our energy resources. However, a problem is how to extract it. They affect the seafloor environment by influencing slope stability. This leads to a lower sea-level and a decreased pressure, which destabilizes gas hydrates and generates gas. This can cause slope destabilization, which leads to further depressurization and destabilization of more gas hydrate. Methane is a greenhouse gas, and the increasing of temperature or decreasing of pressure could cause release of methane into the oceans and atmosphere. This would result in a lower sea level and the warming of seawater.
What is the problem with Petrobras and Brazilian government officials?
There have been many oil spills under Petrobras, a Brazillian state-run petroleum company, such as an accident at an ultra-deepwater oil field off Brazil's coast. In addition, government officials were taking bribes from construction companies and allowing construction companies to purposely overcharge the Brazilian government. The bribes totaled an estimated $3 billion.
What are some estimates of how much oil is there?
There is about 176 billion barrels of undiscovered, recoverable resources of oil. In addition, Brazil's Subsalt Polygon may hold enough undiscovered petroleum and gas to supply the world's current oil needs for more than five years
Why here?
These mining sites are near land and fall within the 200-mile exclusive economic zones of island nations, which mean that they are under local, rather than international jurisdiction. Also, well-mapped, high in gold, copper, zinc, and lead content, and already an ore processing facility on nearby land.
What are Back-arc basins?
They are geological basins that are associated with subduction zones, back-arc seafloor spreading, and metal sulfide deposits. They form through back-arc spreading, which is when one plate slides beneath another.
How do salt deposits form on continental margins? What role do salt deposits play in offshore oil and gas deposits?
They form through salt dome traps. Since salt has a low density and can rise upward through more sediment, the salt domes that form as a result can produce traps for oil and gases on continental margins.
1. How do Petroleum deposits form? A. What is the source of organic matter? B. How does this become petroleum: i. how is this chemically transformed, and ii. what two factors drive these reactions? C. How does it become gas?
They occur in basins and start with the accumulation of thick sediment and organic material (source rock). Then, the thermal maturation of organic material takes place, which heats the sediment and organic matter. Lastly, a geological "trap" holds the oil and allows it to accumulate in reservoir rock. plankton It becomes petroleum through the maturation of organic material. The maturation of these organic materials require deep burial and "cracking", which is where hydrocarbons break and get progressively shorter. Two factors that drive these reactions are heat and time. Heat and time cause thermal degradation, or cracking, which progressively makes hydrocarbons shorter and shorter. The end result of this process is Methane, which has only one carbon atom. B and C about cracking, higher heat, longer time, maturation of organic material. Know which has to do with how it is chemically transformed and if how it becomes gas is same process?
In what oceanic "provinces" do Offshore Oil and Gas deposits occur? Why do they occur here, and not at mid-ocean ridges or on the abyssal plain?
They occur on the continental margins: shelf and slope. The reason they occur here is because continental rifting leads to the formation basins that accumulate sediment and other organic matter and traps to hold oil. *I know manganese modules occurs at abyssal plains. What else occurs at abyssal plains and what occurs at mid-ocean ridges?
What causes precipitation of metal sulfides in black smoker chimneys?
This is caused by the cooling and mixing of hot, calcium-rich hydrothermal fluids with cold, sulfate and calcium-rich seawater.
Where is this new oil field A. what ocean province what kind of "trap"?
This new oil field is off Angola and is on the outer continental shelf. Pre-salt layer
Give two examples of how technology has affected the supply and price of oil over the last 20 years.
Two examples are the fracking and technological advances in the mining of places like the Tar Sands. Fracking is a process that involves the high-pressure pumping of fluids like sand and certain chemicals that creates cracks and allows for oil and gas to flow more freely, leading to greater production.
What happens at Subduction Zones? What major ocean province occurs here, and why?
While the new crust forms at mid-ocean ridges, the old crust gets recycled at subduction zones. This recycling of oceanic plates leads to the formation of deep ocean trenches. Deep ocean trenches occur because oceanic plates slide beneath another plate.
Has North Sea production "peaked"?
Yes, North Sea production has peaked.
Has US Oil Production Peaked yet?
Yes, US Oil Production peaked around 1975. However, because of new techonolgy and fracking, the U.S. is currently going through a second peak.
Is this similar to the new finds offshore Brazil, and if so, why?
Yes, it is because both oil fields are formed on the outer continental shelf.
What geological features (or processes) are necessary to form a petroleum deposit or "Reservoir"?
You need a basin in which thick sediment can accumulate and source rock, which is the accumulation of sediment and organic matter. Then, the thermal maturation of organic material takes place, which heats the sediment and organic matter. Lastly, a geological "trap" holds the oil and allows it to accumulate in reservoir rock.
