Oil is produced extracted using different methods depending on geology and location. After recovering the oil, it is sent to refineries to create refined products we use every day, such as gasoline.
The first efforts to tap the oil sands resource began in the mid 20th century using hot water to separate bitumen from sand. Since then the process has evolved into the sophisticated methods we use to extract oil today. Oil is a black, brownish or amber liquid. A complex mix of hydrocarbons including carbon, hydrogen, sulphur, nitrogen, oxygen and metals, oil formed millions of years ago from animal and plant remains deposited in sand and silt, and pressurized by layers of sedimentary rock.
Oil is classified as light, medium, heavy or extra heavy. Heavy oil has a thick consistency that does not flow easily, often requiring advanced technology to extract. The Canadian regions with tight oil reservoirs include the Bakken, which is found primarily in Saskatchewan; several fields in Alberta including Cardium and Viking; and the Montney and Duvernay in Alberta and B.
Oil is recovered extracted using different methods, mostly depending on geology. Conventional oil is extracted from underground reservoirs using traditional drilling and pumping methods. Conventional oil is a liquid at atmospheric temperature and pressure, so it can flow through a wellbore and a pipeline — unlike bitumen oil sands oil which is too thick to flow without being heated or diluted. Conventional oil development is both land-based and offshore.
Unconventional oil cannot be recovered using conventional drilling and pumping methods. Advanced extraction techniques, such as oil sands mining and in situ development, are used to recover heavier oil that does not flow on its own. Oil found in geological formations that make it more difficult to extract, such as light tight oil LTO , is also called unconventional oil because non-traditional techniques are needed to extract the oil from the underground reservoir.
This kind of oil extraction uses horizontal drilling and hydraulic fracturing. Oil recovery in the oil sands uses two main methods: mining or in situ, depending on how deep the oil sands deposits are.
These organisms were the dominant forms of life on earth at the time. As they lived these organisms absorbed energy from the sun and stored it as carbon molecules within their bodies. Once they died their remains sank to the bottom of the oceans or riverbeds and were buried in layers of sand, mud and rock. Over millions of years, the remains were buried deeper and deeper under more sediment and organic materials.
The enormous pressure, high temperatures, and lack of oxygen transformed the organic matter into a waxy substance called kerogen. With even more heat, pressure, and time the kerogen undergoes a process called catagenesis which transforms the kerogen into hydrocarbons. Different combinations of pressure, heat, and the original composition of organic material will determine the type of hydrocarbon formed.
In this case, the hydrocarbons form crude oil. Other examples are asphalt if the temperature is lower, and natural gas if the temperature is higher. After the oil is formed it moves through tiny pores in the surrounding rock from an area of high pressure to low pressure, this is often upwards.
Some oil might make it all the way to the surface where it pools, in other cases the oil will get trapped under impermeable layers of rock or clay where it will form underground reservoirs.
Oil seemingly keeps getting deeper and deeper. In reality, the oil if anything has only ever moved upwards. It is only the drilling for the oil that keeps needing to go deeper, and further, as the higher up and easier to reach oil reservoirs are used up.
The earliest year where data is available, , shows the average depth of oil wells drilled was 3, feet. By the average rose to 6, feet. And the deepest well currently existing is a massive 40, feet deep. Not all drilling is straight down, when they say depth it means how far they had to drill, sometimes this means covering huge horizontal distances too. Geologists are the masters of locating oil.
Often called oil exploration, geologists will look for an area that ticks all the boxes of finding an oil trap aka striking black gold.
Oil is often found in the vast underground reservoirs where ancient seas were once located. Different combinations of heat and pressure can create different forms of hydrocarbons. Some other examples are coal, peat , and natural gas. Sedimentary basins, where ancient seabeds used to lie, are key sources of petroleum.
More than oil deposits have been discovered in the massive Niger Delta basin, and they comprise one of the most productive oil fields in Africa. Chemistry and Classification of Crude Oil The gasoline we use to fuel our cars, the synthetic fabrics of our backpacks and shoes, and the thousands of different useful products made from petroleum come in forms that are consistent and reliable.
However, the crude oil from which these items are produced is neither consistent nor uniform. Other elements such as nitrogen about 0. The way molecules are organized in the hydrocarbon is a result of the original composition of the algae, plants, or plankton from millions of years ago.
The amount of heat and pressure the plants were exposed to also contributes to variations that are found in hydrocarbons and crude oil. Due to this variation, crude oil that is pumped from the ground can consist of hundreds of different petroleum compounds. It is almost always necessary to refine crude oil in order to make useful products. Classification Oil is classified according to three main categories: the geographic location where it was drilled, its sulfur content, and its API gravity a measure of density.
Classification: Geography Oil is drilled all over the world. However, there are three primary sources of crude oil that set reference points for ranking and pricing other oil supplies: Brent Crude, West Texas Intermediate, and Dubai and Oman. Brent Crude is a mixture that comes from 15 different oil fields between Scotland and Norway in the North Sea. These fields supply oil to most of Europe. WTI supplies much of North America with oil.
Dubai crude, also known as Fateh or Dubai-Oman crude, is a light, sour oil that is produced in Dubai, part of the United Arab Emirates. The nearby country of Oman has recently begun producing oil. Dubai and Oman crudes are used as a reference point for pricing Persian Gulf oils that are mostly exported to Asia. Sulfur in crude oil can corrode metal in the refining process and contribute to air pollution.
Petroleum with more than 0. The API has established accepted systems of standards for a variety of oil- and gas-related products, such as gauges, pumps, and drilling machinery. The API has also established several units of measurement. API gravity is a measure of the density of petroleum liquid compared to water. Light oils are preferred because they have a higher yield of hydrocarbons.
Heavier oils have greater concentrations of metals and sulfur, and require more refining. Petroleum Reservoirs Petroleum is found in underground pockets called reservoirs.
Deep beneath the Earth, pressure is extremely high. Petroleum slowly seeps out toward the surface, where there is lower pressure. It continues this movement from high to low pressure until it encounters a layer of rock that is impermeable.
The petroleum then collects in reservoirs, which can be several hundred meters below the surface of the Earth. Oil can also be contained by stratigraphic traps. Different strata, or layers of rock, can have different amounts of porosity. Crude oil migrates easily through a layer of sandstone, for instance, but would be trapped beneath a layer of shale. Geologists, chemists, and engineers look for geological structures that typically trap petroleum. During the process, a small explosion is set off.
Sound waves travel underground, bounce off of the different types of rock, and return to the surface. Sensors on the ground interpret the returning sound waves to determine the underground geological layout and possibility of a petroleum reservoir. The amount of petroleum in a reservoir is measured in barrels or tons. An oil barrel is about 42 gallons. This measurement is usually used by oil producers in the United States.
Oil producers in Europe and Asia tend to measure in metric tons. There are about 6 to 8 barrels of oil in a metric ton. The conversion is imprecise because different varieties of oil weigh different amounts, depending on the amount of impurities.
Crude oil is frequently found in reservoirs along with natural gas. In the past, natural gas was either burned or allowed to escape into the atmosphere.
Now, technology has been developed to capture the natural gas and either reinject it into the well or compress it into liquid natural gas LNG. LNG is easily transportable and has versatile uses. Extracting Petroleum In some places, petroleum bubbles to the surface of the Earth. In parts of Saudi Arabia and Iraq, for instance, porous rock allows oil to seep to the surface in small ponds. However, most oil is trapped in underground oil reservoirs. The total amount of petroleum in a reservoir is called oil-in-place.
These petroleum liquids may be too difficult, dangerous, or expensive to drill. Drilling can either be developmental, exploratory, or directional. Drilling in an area where oil reserves have already been found is called developmental drilling.
Prudhoe Bay, Alaska, has the largest oil reserves in the United States. Developmental drilling in Prudhoe Bay includes new wells and expanding extraction technology. Drilling where there are no known reserves is called exploratory drilling. McCarthy struck oil 38 times in the s, earning millions of dollars. Directional drilling involves drilling vertically to a known source of oil, then veering the drill bit at an angle to access additional resources. Accusations of directional drilling led to the first Gulf War in Iraq accused Kuwait of using directional drilling techniques to extract oil from Iraqi oil reservoirs near the Kuwaiti border.
Iraq subsequently invaded Kuwait, an act which drew international attention and intervention. After the war, the border between Iraq and Kuwait was redrawn, with the reservoirs now belonging to Kuwait. Oil Rigs On land, oil can be drilled with an apparatus called an oil rig or drilling rig. Offshore, oil is drilled from an oil platform.
Primary Production Most modern wells use an air rotary drilling rig, which can operate 24 hours a day. In this process, engines power a drill bit. A drill bit is a cutting tool used to create a circular hole. The drill bits used in air rotary drilling rigs are hollow steel, with tungsten rods used to cut the rock.
Petroleum drill bits can be 36 centimeters 14 inches in diameter. As the drill bit rotates and cuts through the earth, small pieces of rock are chipped off. A powerful flow of air is pumped down the center of the hollow drill, and comes out through the bottom of the drill bit. The air then rushes back toward the surface, carrying with it tiny chunks of rock. Geologists on site can study these pieces of pulverized rock to determine the different rock strata the drill encounters.
When the drill hits oil, some of the oil naturally rises from the ground, moving from an area of high pressure to low pressure. It is also one of the most dangerous, and a piece of equipment called a blowout preventer redistributes pressure to stop such a gusher.
Pumps are used to extract oil. Most oil rigs have two sets of pumps: mud pumps and extraction pumps. Mud pumps circulate drilling fluid. The petroleum industry uses a wide variety of extraction pumps. Which pump to use depends on the geography, quality, and position of the oil reservoir. Submersible pumps, for example, are submerged directly into the fluid.
A gas pump, also called a bubble pump, uses compressed air to force the petroleum to the surface or well. One of the most familiar types of extraction pumps is the pumpjack , the upper part of a piston pump. A crank moves the large, hammer-shaped pumpjack up and down.
Far below the surface, the motion of the pumpjack moves a hollow piston up and down, constantly carrying petroleum back to the surface or well.
Successful drilling sites can produce oil for about 30 years, although some produce for many more decades. Other methods are necessary to extract this petroleum, a process called secondary recovery. Vacuuming the extra oil out was a method used in the s and early 20th century, but it captured only thinner oil components, and left behind great stores of heavy oil.
Water flooding was discovered by accident. In the s, oil producers in Pennsylvania noticed that abandoned oil wells were accumulating rainwater and groundwater. In the world's conversation about energy, one point is beyond debate: Energy makes a vital contribution to people's quality of life, to society and to human progress.
This is true today, and it will remain true in the future. That's why Energy Matters was created. We believe it's important to equip people with unbiased information so they may form opinions, join the conversation and feel confidence in the work and accomplishments of the energy sector.
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