17-2 Oil
What Is Crude Oil, and How Is It Extracted and Processed? Gooey Stuff to Which We Are Addicted
Petroleum, or crude oil (oil as it comes out of the ground), is a thick and gooey liquid consisting of hundreds of combustible hydrocarbons along with small amounts of sulphur, oxygen, and nitrogen impurities.
We have oil today due to a series of 3 geological events taking place:
The first event occurred when sediments buried dead organic material raining down onto seafloors faster than it could decay.
The next event took place eons later when the seafloor sediments ended up with the right depth for pressure and heat to slowly “cook” or convert the buried organic material into oil.
The third geological break came about because the oil was able to collect in porous limestone or sandstone rock covered by an impermeable cap of shale or silt to keep it from escaping and thus making it and other fossil fuels part of the carbon cycle.
Deposits of crude oil and natural gas often are trapped together under a dome deep within the Earth’s crust on land or under the seafloor. The crude oil is dispersed in pores and cracks in under- ground rock formations, somewhat like water saturating a sponge. To extract the oil, a well is drilled into the deposit. Then oil drawn by gravity out of the rock pores and into the bottom of the well is pumped to the surface. On average, producers get only about 35–50% of the oil out of an oil deposit—although some believe that improved drilling technology may increase the recovery rate to 75%.
Who Has the World’s Oil Supplies? OPEC Rules
The 12 countries that make up the Organization of the Petroleum Exporting Countries (OPEC) have at least 71% of the world’s estimated crude oil reserves. Today OPEC’s members are Algeria, Angola, Ecuador, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, United Arab Emirates, and Venezuela.
Case Study: How Much Oil Do Canada and the United States Have? Have and Have-Not
Canada’s oil reserves are concentrated in Alberta. Large areas of oil sands in this province are being developed. Another area of growing importance is the East Coast Hibernia oil field and the nearby White Rose and Terra Nova oil fields. Canada is a net exporter of oil, shipping 30% of its production to the United States every year and keeping 70% for domestic use.
The United States has only 1.6% of the world’s oil reserves. But it uses about 24% of the crude oil extracted worldwide each year (over two-thirds of that for transportation), mostly because oil is usually an abundant, convenient, and cheap fuel.
How Long Will Conventional Oil Supplies Last? The End of the Oil Era Is in Sight
According to various experts, production of the world’s estimated oil reserves is nearing its peak or has already passed its peak. Canada’s oil peak is difficult to predict; the Alberta Energy and Utilities Board estimates that Canada’s oil sands could yield oil for several hundred years at current rates of extraction, but much depends on the price of oil and on advances in mining technology.
We are not yet running out of oil. But once oil production peaks, we will begin sliding down the bell-shaped oil production curve of a nonrenewable resource from 50% depletion toward 80% depletion when it costs too much to extract what is left. At some point during this slide, we will shift from an abundant supply of cheap oil to a dwindling supply of increasingly expensive oil.
According to geologists, known and projected global reserves of oil are expected to be 80% depleted within 42–93 years depending on how rapidly we use oil. If these estimates are correct, oil should be reaching its sunset years sometime this century.
Can We Meet the World’s Growing Demand for Oil? Rapid Exponential Growth Is a Hungry Beast
Suppose we continue to use oil at the current rate with no increase in oil consumption—a highly unlikely assumption. Even under this conservative no-growth estimate:
Saudi Arabia, with the world’s largest crude oil reserves, could supply world oil needs for about 10 years.
Canada, with the world’s second-largest crude oil reserves, could supply world oil needs for about six years.
The estimated reserves in Alaska’s Arctic National Wildlife Refuge, an area that is hotly con- tested as a potential site for fossil fuel extraction, would meet the world’s current oil demand for only 1–5 months or U.S. oil demand for 7–24 months.
Case Study: Why Has the Arctic Suddenly Gained World Attention? New Potential for Oil and Gas Discovery
With Arctic sea ice melting back in response to warmer temperatures, many countries have been showing keen interest in exploring the continental shelf areas of the Arctic for oil and gas potential. The team concluded that approximately 90 billion barrels of oil, 47 trillion cubic metres (1 669 trillion cubic feet) of natural gas, and 44 billion barrels of natural gas liquids may await discovery in the Arctic. About 84% of this is expected to be found offshore on the shallow continental shelf.
The government of Canada will have to be prepared to deal with an unprecedented wave of fossil fuel exploration, geological claims, sovereignty challenges, political friction, and environmental impact.
What Are the Major Advantages and Disadvantages of Conventional Oil? A Difficult Choice
A serious problem is that burning oil or any fossil fuel releases CO2 into the atmosphere and thus can help promote climate change through global warming. Currently, burning oil mostly as gasoline and diesel fuel for transportation accounts for about 43% of global CO2 emissions.
Advantages | Disadvantages |
|---|---|
Ample supply for 42-93 years | Need to find a substitute within 50 years |
Low cost (with huge subsidies) | Artificially low price encourages waste and discourages search for alternatives |
High net energy yield | Air pollution when burned |
Easily transported within and between countries | Releases CO2 when burned |
Low land use | Moderate water pollution |
Technology is well developed | |
Efficient distribution system |
How Useful Are Heavy Oils from Oil Sand and Oil Shale? Can Heavier Substitutes Save the Day?
Oil that must be extracted from substrate such as sand or rock by means of specialized processes is termed unconventional oil. Oil sand, is a mixture of clay, sand, water, and a combustible organic material called bitumen—a thick and sticky heavy oil with a high sulphur content.
About 80% of Alberta’s oil sands are too deep to permit open-pit surface mining. In this case, the bitumen can be extracted by one of several in situ methods that cause relatively little disturbance com- pared to surface mining. Cyclic steam stimulation involves softening the bitumen with steam and then extracting it; this method uses a vertical well to inject steam and extract bitumen, so it works best where the bitumen deposits run vertically.
Currently these deposits supply about a half of Canada’s oil needs and this proportion is expected to increase. Because of the dramatic reductions in development and production costs, the oil industry has begun counting Canada’s oil sands as reserves of conventional oil. This means that Canada has 12% of the world’s oil reserves, making it number three after Saudi Arabia and Venezuela.
Another potential source of oil is deposits of oil shale, which is neither oil nor shale rock. Instead, oil shales are fine-grained sedimentary rocks containing a solid combustible mixture of hydrocarbons called kerogen. It can be distilled from crushed oil shale rock by heating it in a large container to yield shale oil.