We at Seisma Energy Research, AVV (formerly Seisma Oil Research, LLC) thought you might be interested in learning a little bit about West Texas.
West Texas is a region in Texas that has more in common geographically with the Southwestern United States than it does with the rest of the state. This part of Texas is in the Northern Chihuahuan Desert and the high mountain areas have a climate of cold nights and warm afternoons in winter; hot days and cool nights in the summer.
Population
West Texas has a much lower population density than the rest of the state. It was once mostly inhabited by nomadic Native American tribes such as the Apache, Comanche, and Kiowa until after the Civil War. It does not have as many ties to other parts of the Southern United States as does East Texas, although many of the people who currently populate West Texas are also migrants from other parts of Texas and other Southern states or their descendants. There is a very large Hispanic population, especially near the Rio Grande. Many Mexicans fled Ojinaga and walked to Stonewall during the Mexican revolution in the early days of the 20th century. Many Mexican-Americans still have close family ties in Mexico.
Climate
West Texas receives much less rainfall than the rest of Texas and has an arid or semi-arid climate, requiring most of its scant agriculture to be heavily dependent on irrigation. This irrigation, and water taken out farther North for the needs of El Paso and Juarez, Mexico, has reduced both the Pecos River and the once mighty Rio Grande to a stream in some places, even dry at times. Much of West Texas has rugged terrain including many small mountain ranges while there are none in other parts of the state. West Texas contains part of the Chihuahuan Desert and also the Southern Great Plains, known as the Llano Estacado.
Politics
The area is known for its conservative politics — some of the most heavily Republican counties in the United States are located in the region, where former President George W. Bush spent his early youth. Republican candidates often win in this region by well over 70 percent of the vote. Glasscock County, for instance, gave over 90 percent of the vote to the Republican candidate in both 2004 and 2008.
This region was one of the first areas of Texas to abandon its Democratic roots; some counties (such as Midland) haven't supported a Democrat for president since 1948. However, Democrats continued to win most local races well into the 1990s.
In contrast, El Paso is heavily Democratic, and in the 2008 Presidential election, El Paso, Culberson, Reeves, Presidio, and Brewster-counties-all with large Hispanic populations-- were won by Democrat Barack Obama.
Industry
Major industries include livestock, petroleum and natural gas production, textiles such as cotton, grain farming and because of its proximity to the Mexican border, the maquiladora industry. West Texas has become notable for its numerous wind turbines producing clean, alternative electricity.
Friday, September 18, 2009
CRACKING OIL
Seisma Energy Research, AVV (formerly Seisma Oil Research, LLC) presents this article as part of a series of articles on understanding the energy business. We hope you enjoy this series.
Overview
In petroleum geology and chemistry, cracking is the process whereby complex organic molecules such as kerogens or heavy hydrocarbons are broken down into simpler molecules (e.g. light hydrocarbons) by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products are strongly dependent on the temperature and presence of any catalysts. Cracking, also referred to as pyrolysis, is the breakdown of a large alkane into smaller, more useful alkanes and an alkene. Simply put, hydrocarbons cracking is the process of breaking long chain hydrocarbons into short ones.
History
In 1855, petroleum cracking methods were pioneered by American chemistry professor, Benjamin Silliman, Jr., of Sheffield Scientific School (SSS) at Yale University.
The first thermal cracking method, the Shukhov cracking process, was invented by Russian engineer Vladimir Shukhov, in the Russian empire, Patent No. 12926, November 27, 1891.
Eugene Houdry, a French mechanical engineer, pioneered catalytic cracking and developed the first commercially successful process after emigrating to the United States. The first commercial plant was built in 1936. His process doubled the amount of gasoline that could be produced from a barrel of crude oil.
Applications
Oil refinery cracking processes allow the production of "light" products such as LPG and gasoline from heavier crude oil distillation fractions such as gas oils and residues. Fluid catalytic cracking produces a high yield of gasoline and LPG, while hydrocracking is a major source of jet fuel, diesel, naphtha and LPG.
Thermal cracking is currently used to "upgrade" very heavy fractions ("upgrading", "visbreaking"), or to produce light fractions or distillates, burner fuel and/or petroleum coke. Two extremes of the thermal cracking in terms of product range are represented by the high-temperature process called "steam cracking" or pyrolysis (ca. 750 to 900 °C or more) which produces valuable ethylene and other feedstocks for the petrochemical industry, and the milder-temperature delayed coking (ca. 500 °C) which can produce, under the right conditions, valuable needle coke, a highly crystalline petroleum coke used in the production of electrodes for the steel and aluminium industries.
Overview
In petroleum geology and chemistry, cracking is the process whereby complex organic molecules such as kerogens or heavy hydrocarbons are broken down into simpler molecules (e.g. light hydrocarbons) by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products are strongly dependent on the temperature and presence of any catalysts. Cracking, also referred to as pyrolysis, is the breakdown of a large alkane into smaller, more useful alkanes and an alkene. Simply put, hydrocarbons cracking is the process of breaking long chain hydrocarbons into short ones.
History
In 1855, petroleum cracking methods were pioneered by American chemistry professor, Benjamin Silliman, Jr., of Sheffield Scientific School (SSS) at Yale University.
The first thermal cracking method, the Shukhov cracking process, was invented by Russian engineer Vladimir Shukhov, in the Russian empire, Patent No. 12926, November 27, 1891.
Eugene Houdry, a French mechanical engineer, pioneered catalytic cracking and developed the first commercially successful process after emigrating to the United States. The first commercial plant was built in 1936. His process doubled the amount of gasoline that could be produced from a barrel of crude oil.
Applications
Oil refinery cracking processes allow the production of "light" products such as LPG and gasoline from heavier crude oil distillation fractions such as gas oils and residues. Fluid catalytic cracking produces a high yield of gasoline and LPG, while hydrocracking is a major source of jet fuel, diesel, naphtha and LPG.
Thermal cracking is currently used to "upgrade" very heavy fractions ("upgrading", "visbreaking"), or to produce light fractions or distillates, burner fuel and/or petroleum coke. Two extremes of the thermal cracking in terms of product range are represented by the high-temperature process called "steam cracking" or pyrolysis (ca. 750 to 900 °C or more) which produces valuable ethylene and other feedstocks for the petrochemical industry, and the milder-temperature delayed coking (ca. 500 °C) which can produce, under the right conditions, valuable needle coke, a highly crystalline petroleum coke used in the production of electrodes for the steel and aluminium industries.
THE PERMIAN BASIN
Seisma Energy Research, AVV (formerly Seisma Oil Research, LLC) presents this article as part of a series of articles on understanding the energy business. We hope you enjoy this series.
The Permian Basin is a sedimentary basin largely contained in the western part of the U.S. state of Texas and the southeastern part of the state of New Mexico. It reaches from just south of Lubbock, Texas, to just south of Midland & Odessa, extending westward into the southeastern part of the adjacent state of New Mexico. It is so named because it has one of the world's thickest deposits of rocks from the Permian geologic period. The greater Permian Basin comprises several component basins: of these, Midland Basin is the largest, Delaware Basin is the second largest, and Marfa Basin is the smallest. The Permian Basin extends beneath an area approximately 250 miles wide and 300 miles long.
The Permian Basin gives its name to a large oil and natural gas producing area, part of the Mid-Continent Oil Producing Area. Total production for that region up to the beginning of 1993 was over 14.9 billion barrels. The towns of Midland and Odessa serve as the headquarters for oil production activities in the basin.
The Permian Basin is also a major source of potassium salts (potash), which are mined from bedded deposits of sylvite and langbeinite in the Salado Formation of Permian age. Sylvite was discovered in drill cores in 1925, and production began in 1931. The mines are located in Lea and Eddy counties, New Mexico, and are operated by the room and pillar method. Halite (rock salt) is produced as a byproduct of potash mining.
The Permian Basin is a sedimentary basin largely contained in the western part of the U.S. state of Texas and the southeastern part of the state of New Mexico. It reaches from just south of Lubbock, Texas, to just south of Midland & Odessa, extending westward into the southeastern part of the adjacent state of New Mexico. It is so named because it has one of the world's thickest deposits of rocks from the Permian geologic period. The greater Permian Basin comprises several component basins: of these, Midland Basin is the largest, Delaware Basin is the second largest, and Marfa Basin is the smallest. The Permian Basin extends beneath an area approximately 250 miles wide and 300 miles long.
The Permian Basin gives its name to a large oil and natural gas producing area, part of the Mid-Continent Oil Producing Area. Total production for that region up to the beginning of 1993 was over 14.9 billion barrels. The towns of Midland and Odessa serve as the headquarters for oil production activities in the basin.
The Permian Basin is also a major source of potassium salts (potash), which are mined from bedded deposits of sylvite and langbeinite in the Salado Formation of Permian age. Sylvite was discovered in drill cores in 1925, and production began in 1931. The mines are located in Lea and Eddy counties, New Mexico, and are operated by the room and pillar method. Halite (rock salt) is produced as a byproduct of potash mining.
Thursday, September 17, 2009
OIL WELLS
Seisma Energy Research, AVV (formerly Seisma Oil Research, LLC) presents this article as part of a series of articles on understanding the energy business. We hope you enjoy this series.
Overview
An oil well is a general term for any boring through the earth's surface that is designed to find and produce petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil. A well designed to produce mainly or only gas may be termed a gas well.
History
The earliest known oil wells were drilled in China in 347 CE. They had depths of up to about 800 feet (240 m) and were drilled using bits attached to bamboo poles. The oil was burned to evaporate brine and produce salt. By the 10th century, extensive bamboo pipelines connected oil wells with salt springs. The ancient records of China and Japan are said to contain many allusions to the use of natural gas for lighting and heating. Petroleum was known as burning water in Japan in the 7th century.
The Middle East's petroleum industry was established by the 8th century, when the streets of the newly constructed Baghdad were paved with tar, derived from petroleum that became accessible from natural fields in the region. Petroleum was distilled by the Persian alchemist Muhammad ibn Zakarīya Rāzi (Rhazes) in the 9th century, producing chemicals such as kerosene in the alembic (al-ambiq),[and which was mainly used for kerosene lamps. Arab and Persian chemists also distilled crude oil in order to produce flammable products for military purposes. Through Islamic Spain, distillation became available in Western Europe by the 12th century.
Some sources claim that from the 9th century, oil fields were exploited in the area around modern Baku, Azerbaijan, to produce naphtha for the petroleum industry. These fields were described by Marco Polo in the 13th century, who described the output of those oil wells as hundreds of shiploads. When Marco Polo in 1264 visited the Azerbaijani city of Baku, on the shores of the Caspian Sea, he saw oil being collected from seeps. He wrote that "on the confines toward Geirgine there is a fountain from which oil springs in great abundance, inasmuch as a hundred shiploads might be taken from it at one time."
Shallow pits were dug at the Baku seeps in ancient times to facilitate collecting oil, and hand-dug holes up to 35 meters (115 ft) deep were in use by 1594. These holes were essentially oil wells. Apparently 116 of these wells in 1830 produced 3,840 metric tons (about 28000 barrels) of oil. In 1849, Russian engineer F.N. Semyenov used a cable tool to drill an oil well on the Apsheron Peninsula, ten years before Colonel Drake's famous well in Pennsylvania. Also, offshore drilling started up at Baku at Bibi-Eibat field near the end of the 19th century, about the same time that the first offshore oil well was drilled in 1896 at Summerland field on the California Coast.
The earliest oil wells in modern times were drilled percussively, by hammering a cable tool into the earth. Soon after, cable tools were replaced with rotary drilling, which could drill boreholes to much greater depths and in less time. The record-depth Kola Borehole used non-rotary mud motor drilling to achieve a depth of over 12 000 meters (38,000 ft). Until the 1970s, most oil wells were vertical, although lithological and mechanical imperfections cause most wells to deviate at least slightly from true vertical.
However, modern directional drilling technologies allow for strongly deviated wells which can, given sufficient depth and with the proper tools, actually become horizontal. This is of great value as the reservoir rocks which contain hydrocarbons are usually horizontal, or sub-horizontal; a horizontal wellbore placed in a production zone has more surface area in the production zone than a vertical well, resulting in a higher production rate. The use of deviated and horizontal drilling has also made it possible to reach reservoirs several kilometers or miles away from the drilling location (extended reach drilling), allowing for the production of hydrocarbons located below locations that are either difficult to place a drilling rig on, environmentally sensitive, or populated.
Life of a Well
The creation and life of a well can be divided up into five segments:
• Planning
• Drilling
• Completion
• Production
• Abandonment
Types of Wells
Oil wells come in many varieties. By produced fluid, there can be wells that produce oil, wells that produce oil and natural gas, or wells that only produce natural gas. Natural gas is almost always a byproduct of producing oil, since the small, light gas carbon chains come out of solution as it undergoes pressure reduction from the reservoir to the surface, similar to uncapping a bottle of soda pop where the carbon dioxide effervesces. Unwanted natural gas can be a disposal problem at the well site. If there is not a market for natural gas near the wellhead it is virtually valueless since it must be piped to the end user. Until recently, such unwanted gas was burned off at the wellsite, but due to environmental concerns this practice is becoming less common. Often, unwanted (or 'stranded' gas without a market) gas is pumped back into the reservoir with an 'injection' well for disposal or repressurizing the producing formation.
Another solution is to export the natural gas as a liquid. Gas-to-liquid, (GTL) is a developing technology that converts stranded natural gas into synthetic gasoline, diesel or jet fuel through the Fischer-Tropsch process developed in World War II Germany. Such fuels can be transported through conventional pipelines and tankers to users. Proponents claim GTL fuels burn cleaner than comparable petroleum fuels. Most major international oil companies are in advanced development stages of GTL production, with a world-scale (140,000 bbl/day) GTL plant in Qatar scheduled to come online before 2010. In locations such as the United States with a high natural gas demand, pipelines are constructed to take the gas from the wellsite to the end consumer.
Another obvious way to classify oil wells is by land or offshore wells. There is very little difference in the well itself. An offshore well targets a reservoir that happens to be underneath an ocean. Due to logistics, drilling an offshore well is far more costly than an onshore well. By far the most common type is the onshore well. These wells dot the Southern and Central Great Plains, Southwestern United States, and are the most common wells in the Middle East.
Another way to classify oil wells is by their purpose in contributing to the development of a resource. They can be characterized as:
• production wells are drilled primarily for producing oil or gas, once the producing structure and characteristics are determined
• appraisal wells are used to assess characteristics (such as flow rate) of a proven hydrocarbon accumulation
• exploration wells are drilled purely for exploratory (information gathering) purposes in a new area
• wildcat wells are those drilled outside of and not in the vicinity of known oil or gas fields.
At a producing well site, active wells may be further categorised as:
• oil producers producing predominantly liquid hydrocarbons, but mostly with some associated gas.
• gas producers producing almost entirely gaseous hydrocarbons.
• water injectors injecting water into the formation to maintain reservoir pressure or simply to dispose of water produced with the hydrocarbons because even after treatment, it would be too oily and too saline to be considered clean for dumping overboard, let alone into a fresh water source, in the case of onshore wells. Frequently water injection has an element of reservoir management and produced water disposal.
• aquifer producers intentionally producing reservoir water for re-injection to manage pressure. This is in effect moving reservoir water from where it is not as useful to where it is more useful. These wells will generally only be used if produced water from the oil or gas producers is insufficient for reservoir management purposes. Using aquifer produced water rather than sea water is due to the chemistry.
• gas injectors injecting gas into the reservoir often as a means of disposal or sequestering for later production, but also to maintain reservoir pressure.
Overview
An oil well is a general term for any boring through the earth's surface that is designed to find and produce petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil. A well designed to produce mainly or only gas may be termed a gas well.
History
The earliest known oil wells were drilled in China in 347 CE. They had depths of up to about 800 feet (240 m) and were drilled using bits attached to bamboo poles. The oil was burned to evaporate brine and produce salt. By the 10th century, extensive bamboo pipelines connected oil wells with salt springs. The ancient records of China and Japan are said to contain many allusions to the use of natural gas for lighting and heating. Petroleum was known as burning water in Japan in the 7th century.
The Middle East's petroleum industry was established by the 8th century, when the streets of the newly constructed Baghdad were paved with tar, derived from petroleum that became accessible from natural fields in the region. Petroleum was distilled by the Persian alchemist Muhammad ibn Zakarīya Rāzi (Rhazes) in the 9th century, producing chemicals such as kerosene in the alembic (al-ambiq),[and which was mainly used for kerosene lamps. Arab and Persian chemists also distilled crude oil in order to produce flammable products for military purposes. Through Islamic Spain, distillation became available in Western Europe by the 12th century.
Some sources claim that from the 9th century, oil fields were exploited in the area around modern Baku, Azerbaijan, to produce naphtha for the petroleum industry. These fields were described by Marco Polo in the 13th century, who described the output of those oil wells as hundreds of shiploads. When Marco Polo in 1264 visited the Azerbaijani city of Baku, on the shores of the Caspian Sea, he saw oil being collected from seeps. He wrote that "on the confines toward Geirgine there is a fountain from which oil springs in great abundance, inasmuch as a hundred shiploads might be taken from it at one time."
Shallow pits were dug at the Baku seeps in ancient times to facilitate collecting oil, and hand-dug holes up to 35 meters (115 ft) deep were in use by 1594. These holes were essentially oil wells. Apparently 116 of these wells in 1830 produced 3,840 metric tons (about 28000 barrels) of oil. In 1849, Russian engineer F.N. Semyenov used a cable tool to drill an oil well on the Apsheron Peninsula, ten years before Colonel Drake's famous well in Pennsylvania. Also, offshore drilling started up at Baku at Bibi-Eibat field near the end of the 19th century, about the same time that the first offshore oil well was drilled in 1896 at Summerland field on the California Coast.
The earliest oil wells in modern times were drilled percussively, by hammering a cable tool into the earth. Soon after, cable tools were replaced with rotary drilling, which could drill boreholes to much greater depths and in less time. The record-depth Kola Borehole used non-rotary mud motor drilling to achieve a depth of over 12 000 meters (38,000 ft). Until the 1970s, most oil wells were vertical, although lithological and mechanical imperfections cause most wells to deviate at least slightly from true vertical.
However, modern directional drilling technologies allow for strongly deviated wells which can, given sufficient depth and with the proper tools, actually become horizontal. This is of great value as the reservoir rocks which contain hydrocarbons are usually horizontal, or sub-horizontal; a horizontal wellbore placed in a production zone has more surface area in the production zone than a vertical well, resulting in a higher production rate. The use of deviated and horizontal drilling has also made it possible to reach reservoirs several kilometers or miles away from the drilling location (extended reach drilling), allowing for the production of hydrocarbons located below locations that are either difficult to place a drilling rig on, environmentally sensitive, or populated.
Life of a Well
The creation and life of a well can be divided up into five segments:
• Planning
• Drilling
• Completion
• Production
• Abandonment
Types of Wells
Oil wells come in many varieties. By produced fluid, there can be wells that produce oil, wells that produce oil and natural gas, or wells that only produce natural gas. Natural gas is almost always a byproduct of producing oil, since the small, light gas carbon chains come out of solution as it undergoes pressure reduction from the reservoir to the surface, similar to uncapping a bottle of soda pop where the carbon dioxide effervesces. Unwanted natural gas can be a disposal problem at the well site. If there is not a market for natural gas near the wellhead it is virtually valueless since it must be piped to the end user. Until recently, such unwanted gas was burned off at the wellsite, but due to environmental concerns this practice is becoming less common. Often, unwanted (or 'stranded' gas without a market) gas is pumped back into the reservoir with an 'injection' well for disposal or repressurizing the producing formation.
Another solution is to export the natural gas as a liquid. Gas-to-liquid, (GTL) is a developing technology that converts stranded natural gas into synthetic gasoline, diesel or jet fuel through the Fischer-Tropsch process developed in World War II Germany. Such fuels can be transported through conventional pipelines and tankers to users. Proponents claim GTL fuels burn cleaner than comparable petroleum fuels. Most major international oil companies are in advanced development stages of GTL production, with a world-scale (140,000 bbl/day) GTL plant in Qatar scheduled to come online before 2010. In locations such as the United States with a high natural gas demand, pipelines are constructed to take the gas from the wellsite to the end consumer.
Another obvious way to classify oil wells is by land or offshore wells. There is very little difference in the well itself. An offshore well targets a reservoir that happens to be underneath an ocean. Due to logistics, drilling an offshore well is far more costly than an onshore well. By far the most common type is the onshore well. These wells dot the Southern and Central Great Plains, Southwestern United States, and are the most common wells in the Middle East.
Another way to classify oil wells is by their purpose in contributing to the development of a resource. They can be characterized as:
• production wells are drilled primarily for producing oil or gas, once the producing structure and characteristics are determined
• appraisal wells are used to assess characteristics (such as flow rate) of a proven hydrocarbon accumulation
• exploration wells are drilled purely for exploratory (information gathering) purposes in a new area
• wildcat wells are those drilled outside of and not in the vicinity of known oil or gas fields.
At a producing well site, active wells may be further categorised as:
• oil producers producing predominantly liquid hydrocarbons, but mostly with some associated gas.
• gas producers producing almost entirely gaseous hydrocarbons.
• water injectors injecting water into the formation to maintain reservoir pressure or simply to dispose of water produced with the hydrocarbons because even after treatment, it would be too oily and too saline to be considered clean for dumping overboard, let alone into a fresh water source, in the case of onshore wells. Frequently water injection has an element of reservoir management and produced water disposal.
• aquifer producers intentionally producing reservoir water for re-injection to manage pressure. This is in effect moving reservoir water from where it is not as useful to where it is more useful. These wells will generally only be used if produced water from the oil or gas producers is insufficient for reservoir management purposes. Using aquifer produced water rather than sea water is due to the chemistry.
• gas injectors injecting gas into the reservoir often as a means of disposal or sequestering for later production, but also to maintain reservoir pressure.
PETROLEUM INDUSTRY
Seisma Energy Research, AVV (formerly Seisma Oil Research, LLC) presents this article as part of a series of articles on understanding the energy business. We hope you enjoy this series.
Overview
The petroleum industry includes the global processes of exploration, extraction, refining, transporting (often by oil tankers and pipelines), and marketing petroleum products. The largest volume products of the industry are fuel oil and gasoline (petrol). Petroleum is also the raw material for many chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, and plastics. The industry is usually divided into three major components: upstream, midstream and downstream. Midstream operations are usually included in the downstream category.
Petroleum is vital to many industries, and is of importance to the maintenance of industrialized civilization itself, and thus is a critical concern for many nations. Oil accounts for a large percentage of the world’s energy consumption, ranging from a low of 32% for Europe and Asia, up to a high of 53% for the Middle East. Other geographic regions’ consumption patterns are as follows: South and Central America (44%), Africa (41%), and North America (40%). The world consumes 30 billion barrels (4.8 km³) of oil per year, with developed nations being the largest consumers. The United States consumed 25% of the oil produced in 2007. The production, distribution, refining, and retailing of petroleum taken as a whole represents the world's largest industry in terms of dollar value.
History
Natural History
Petroleum is a naturally occurring liquid found in rock formations. It consists of a complex mixture of hydrocarbons of various molecular weights, plus other organic compounds. It is generally accepted that oil, like other fossil fuels, formed from the fossilized remains of dead plants and animals by exposure to heat and pressure in the Earth's crust over hundreds of millions of years. Over time, the decayed residue was covered by layers of mud and silt, sinking further down into the Earth’s crust and preserved there between hot and pressured layers, gradually transforming into oil reservoirs.
Early History
Petroleum in an unrefined state has been utilized by humans for over 5000 years. Oil in general has been used since early human history to keep fires ablaze, and also for warfare. Ancient Persian language tablets indicate the medicinal and lighting uses of petroleum in the upper echelons of their society. Ancient China was also known to burn skimmed oil for light.
An early petroleum industry was established in the 8th century, when the streets of Baghdad were paved with tar, derived from petroleum through destructive distillation. In the 9th century, oil fields were exploited in the area around modern Baku, Azerbaijan, to produce naphtha. These fields were described by al-Masudi in the 10th century, and by Marco Polo in the 13th century, who described the output of those oil wells as hundreds of shiploads. Petroleum was distilled by al-Razi in the 9th century, producing chemicals such as kerosene in the alembic, which he used to invent kerosene lamps for use in the oil lamp industry.
Its importance in the world economy evolved slowly, with wood and coal used for heating and cooking, and whale oil used for lighting well into the 19th Century. A petroleum industry emerged in North America in Canada and the United States, fueling the industrial revolution. The Industrial Revolution generated an increasing need for energy which was fuelled mainly by coal, with other sources including whale oil. However, it was discovered that kerosene could be extracted from crude oil and used as a light and heating fuel. Petroleum was in great demand, and by the twentieth century had become the most valuable commodity traded on the world market.
Modern History
Imperial Russia produced 3,500 tons of oil in 1825 and doubled its output by mid-century After oil drilling began in what is now Azerbaijan in 1848, two large pipelines were built in the Russian Empire: the 833 km long pipeline to transport oil from the Caspian to the Black Sea port of Batumi (Baku-Batumi pipeline), completed in 1906, and the 162 km long pipeline to carry oil from Chechnya to the Caspian.
At the turn of the 20th century, Imperial Russia's output of oil, almost entirely from the Apsheron Peninsula, accounted for half of the world's production and dominated international markets. Nearly 200 small refineries operated in the suburbs of Baku by 1884. As a side effect of these early developments, the Apsheron Peninsula emerged as the world's "oldest legacy of oil pollution and environmental negligence." In 1878, Ludvig Nobel and his Branobel company "revolutionized oil transport" by commissioning the first oil tanker and launching it on the Caspian Sea.
The first modern oil refineries were built by Ignacy Łukasiewicz near Jasło (then in the dependent Kingdom of Galicia and Lodomeria in Central European Galicia), Poland from 1854–56. These were initially small as demand for refined fuel was limited. The refined products were used in artificial asphalt, machine oil and lubricants, in addition to Łukasiewicz's kerosene lamp. As kerosene lamps gained popularity, the refining industry grew in the area.
The first large oil refinery opened at Ploieşti, Romania in 1856.
The first oil drilling in the United States began in 1859, when oil was successfully drilled in Titusville, Pennsylvania. In the first quarter of the 20th century, the United States overtook Russia as the world's largest oil producer.
By the 1920s, oil fields had been established in many countries including Canada, Poland, Sweden, the Ukraine, the United States, and Venezuela.
In 1947, the Superior Oil Company constructed the first offshore oil platform off the Gulf Coast of Louisiana.
Environmental Impact and Future Shortages
Some petroleum industry operations have been responsible for water pollution, through by-products of refining, and oil spills.
The combustion of fossil fuels produces greenhouse gases and other air pollutants as by-products. Pollutants include nitrogen oxides, sulphur dioxide, volatile organic compounds and heavy metals.
As petroleum is a non-renewable natural resource the industry is faced with an inevitable eventual depletion of the world's oil supply. The BP Statistical Review of World Energy 2007 predicted the reserve/production ratio for proven resources worldwide. The study placed the prospective life span of reserves in the Middle East at 79.5 years, Latin America at 41.2 years and North America at only 12 years. The global reserve/production ratio estimates that at current production levels, the world's oil reserves will be depleted in 40.5 years.
The Hubbert peak theory, which introduced the concept of peak oil, questions the sustainability of oil production. It suggests that after a peak in oil production rates, a period of oil depletion will ensue.
According to research by IBISWorld, biofuels (primarily ethanol, but also biodiesel) will continue to supplement petroleum. However output levels are low, and these fuels will not displace local oil production. Ethanol is viewed as offering a lower environmental impact, and will play a small role in reducing dependence on imported crude oil. More than 90% of the ethanol used in the US is blended with gasoline to produce a 10% ethanol mix, lifting the oxygen content of the fuel.
Overview
The petroleum industry includes the global processes of exploration, extraction, refining, transporting (often by oil tankers and pipelines), and marketing petroleum products. The largest volume products of the industry are fuel oil and gasoline (petrol). Petroleum is also the raw material for many chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, and plastics. The industry is usually divided into three major components: upstream, midstream and downstream. Midstream operations are usually included in the downstream category.
Petroleum is vital to many industries, and is of importance to the maintenance of industrialized civilization itself, and thus is a critical concern for many nations. Oil accounts for a large percentage of the world’s energy consumption, ranging from a low of 32% for Europe and Asia, up to a high of 53% for the Middle East. Other geographic regions’ consumption patterns are as follows: South and Central America (44%), Africa (41%), and North America (40%). The world consumes 30 billion barrels (4.8 km³) of oil per year, with developed nations being the largest consumers. The United States consumed 25% of the oil produced in 2007. The production, distribution, refining, and retailing of petroleum taken as a whole represents the world's largest industry in terms of dollar value.
History
Natural History
Petroleum is a naturally occurring liquid found in rock formations. It consists of a complex mixture of hydrocarbons of various molecular weights, plus other organic compounds. It is generally accepted that oil, like other fossil fuels, formed from the fossilized remains of dead plants and animals by exposure to heat and pressure in the Earth's crust over hundreds of millions of years. Over time, the decayed residue was covered by layers of mud and silt, sinking further down into the Earth’s crust and preserved there between hot and pressured layers, gradually transforming into oil reservoirs.
Early History
Petroleum in an unrefined state has been utilized by humans for over 5000 years. Oil in general has been used since early human history to keep fires ablaze, and also for warfare. Ancient Persian language tablets indicate the medicinal and lighting uses of petroleum in the upper echelons of their society. Ancient China was also known to burn skimmed oil for light.
An early petroleum industry was established in the 8th century, when the streets of Baghdad were paved with tar, derived from petroleum through destructive distillation. In the 9th century, oil fields were exploited in the area around modern Baku, Azerbaijan, to produce naphtha. These fields were described by al-Masudi in the 10th century, and by Marco Polo in the 13th century, who described the output of those oil wells as hundreds of shiploads. Petroleum was distilled by al-Razi in the 9th century, producing chemicals such as kerosene in the alembic, which he used to invent kerosene lamps for use in the oil lamp industry.
Its importance in the world economy evolved slowly, with wood and coal used for heating and cooking, and whale oil used for lighting well into the 19th Century. A petroleum industry emerged in North America in Canada and the United States, fueling the industrial revolution. The Industrial Revolution generated an increasing need for energy which was fuelled mainly by coal, with other sources including whale oil. However, it was discovered that kerosene could be extracted from crude oil and used as a light and heating fuel. Petroleum was in great demand, and by the twentieth century had become the most valuable commodity traded on the world market.
Modern History
Imperial Russia produced 3,500 tons of oil in 1825 and doubled its output by mid-century After oil drilling began in what is now Azerbaijan in 1848, two large pipelines were built in the Russian Empire: the 833 km long pipeline to transport oil from the Caspian to the Black Sea port of Batumi (Baku-Batumi pipeline), completed in 1906, and the 162 km long pipeline to carry oil from Chechnya to the Caspian.
At the turn of the 20th century, Imperial Russia's output of oil, almost entirely from the Apsheron Peninsula, accounted for half of the world's production and dominated international markets. Nearly 200 small refineries operated in the suburbs of Baku by 1884. As a side effect of these early developments, the Apsheron Peninsula emerged as the world's "oldest legacy of oil pollution and environmental negligence." In 1878, Ludvig Nobel and his Branobel company "revolutionized oil transport" by commissioning the first oil tanker and launching it on the Caspian Sea.
The first modern oil refineries were built by Ignacy Łukasiewicz near Jasło (then in the dependent Kingdom of Galicia and Lodomeria in Central European Galicia), Poland from 1854–56. These were initially small as demand for refined fuel was limited. The refined products were used in artificial asphalt, machine oil and lubricants, in addition to Łukasiewicz's kerosene lamp. As kerosene lamps gained popularity, the refining industry grew in the area.
The first large oil refinery opened at Ploieşti, Romania in 1856.
The first oil drilling in the United States began in 1859, when oil was successfully drilled in Titusville, Pennsylvania. In the first quarter of the 20th century, the United States overtook Russia as the world's largest oil producer.
By the 1920s, oil fields had been established in many countries including Canada, Poland, Sweden, the Ukraine, the United States, and Venezuela.
In 1947, the Superior Oil Company constructed the first offshore oil platform off the Gulf Coast of Louisiana.
Environmental Impact and Future Shortages
Some petroleum industry operations have been responsible for water pollution, through by-products of refining, and oil spills.
The combustion of fossil fuels produces greenhouse gases and other air pollutants as by-products. Pollutants include nitrogen oxides, sulphur dioxide, volatile organic compounds and heavy metals.
As petroleum is a non-renewable natural resource the industry is faced with an inevitable eventual depletion of the world's oil supply. The BP Statistical Review of World Energy 2007 predicted the reserve/production ratio for proven resources worldwide. The study placed the prospective life span of reserves in the Middle East at 79.5 years, Latin America at 41.2 years and North America at only 12 years. The global reserve/production ratio estimates that at current production levels, the world's oil reserves will be depleted in 40.5 years.
The Hubbert peak theory, which introduced the concept of peak oil, questions the sustainability of oil production. It suggests that after a peak in oil production rates, a period of oil depletion will ensue.
According to research by IBISWorld, biofuels (primarily ethanol, but also biodiesel) will continue to supplement petroleum. However output levels are low, and these fuels will not displace local oil production. Ethanol is viewed as offering a lower environmental impact, and will play a small role in reducing dependence on imported crude oil. More than 90% of the ethanol used in the US is blended with gasoline to produce a 10% ethanol mix, lifting the oxygen content of the fuel.
Tuesday, September 15, 2009
SEISMA 3D RIG
Seisma 3D Rig Application
Seisma Energy Research, AVV (formerly Seisma Oil Research, LLC) has a 3D Oil Rig Application on their website. It is definitely worth a look. It is very interesting. Here is the link:
http://www.seismaresearch.com/media/3d_rig.html
Seisma Energy Research, AVV (formerly Seisma Oil Research, LLC) has a 3D Oil Rig Application on their website. It is definitely worth a look. It is very interesting. Here is the link:
http://www.seismaresearch.com/media/3d_rig.html
PETROLEUM (CRUDE OIL)
Seisma Energy Research, AVV (formerly Seisma Oil Research, LLC) presents this article as part of a series of articles on understanding the energy business. We hope you enjoy this series.
Overview
Petroleum (or crude oil) is a naturally occurring, flammable liquid found in rock formations in the Earth consisting of a complex mixture of hydrocarbons of various molecular weights, plus other organic compounds.
The term "petroleum" was first used in the treatise De Natura Fossilium, published in 1546 by the German mineralogist Georg Bauer, also known as Georgius Agricola.
Composition
In its strictest sense, petroleum includes only crude oil, but in common usage it includes both crude oil and natural gas. Both crude oil and natural gas are predominantly a mixture of hydrocarbons. Under surface pressure and temperature conditions, the lighter hydrocarbons methane, ethane, propane and butane occur as gases, while the heavier ones from pentane and up are in the form of liquids or solids. However, in the underground oil reservoir the proportion which is gas or liquid varies depending on the subsurface conditions, and on the phase diagram of the petroleum mixture,
An oil well produces predominantly crude oil, with some natural gas dissolved in it. Because the pressure is lower at the surface than underground, some of the gas will come out of solution and be recovered as associated gas or solution gas. A gas well produces predominately natural gas. However, because the underground temperature and pressure are higher than at the surface, the gas may contain heavier hydrocarbons such as pentane, hexane, and heptane in the gaseous state. Under surface conditions these will condense out of the gas and form natural gas condensate, often shortened to condensate. Condensate resembles gasoline in appearance and is similar in composition to some volatile light crude oils.
The proportion of hydrocarbons in the petroleum mixture is highly variable between different oil fields and ranges from as much as 97% by weight in the lighter oils to as little as 50% in the heavier oils and bitumens.
Crude oil varies greatly in appearance depending on its composition. It is usually black or dark brown (although it may be yellowish or even greenish). In the reservoir it is usually found in association with natural gas, which being lighter forms a gas cap over the petroleum, and saline water which, being heavier than most forms of crude oil, generally sinks beneath it. Crude oil may also be found in semi-solid form mixed with sand and water, as in the Athabasca oil sands in Canada, where it is usually referred to as crude bitumen.
Petroleum is used mostly, by volume, for producing fuel oil and gasoline (petrol), both important "primary energy" sources. 84% by volume of the hydrocarbons present in petroleum is converted into energy-rich fuels (petroleum-based fuels), including gasoline, diesel, jet, heating, and other fuel oils, and liquefied petroleum gas. The lighter grades of crude oil produce the best yields of these products, but as the world's reserves of light and medium oil are depleted, oil refineries are increasingly having to process heavy oil and bitumen, and use more complex and expensive methods to produce the products required. Because heavier crude oils have too much carbon and not enough hydrogen, these processes generally involve removing carbon from or adding hydrogen to the molecules, and using fluid catalytic cracking to convert the longer, more complex molecules in the oil to the shorter, simpler ones in the fuels.
Due to its high energy density, easy transportability and relative abundance, oil has become the world's most important source of energy since the mid-1950s. Petroleum is also the raw material for many chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, and plastics; the 16% not used for energy production is converted into these other materials.
Petroleum is found in porous rock formations in the upper strata of some areas of the Earth's crust. There is also petroleum in oil sands (tar sands). Known reserves of petroleum are typically estimated at around 190 km3 (1.2 trillion (short scale) barrels) without oil sands, or 595 km3 (3.74 trillion barrels) with oil sands. Consumption is currently around 84 million barrels (13.4×106 m3) per day, or 4.9 km3 per year. Because the energy return over energy invested (EROEI) ratio of oil is constantly falling (due to physical phenomena such as residual oil saturation, and the economic factor of rising marginal extraction costs), recoverable oil reserves are significantly less than total oil in place. At current consumption levels, and assuming that oil will be consumed only from reservoirs, known recoverable reserves would be gone around 2039, potentially leading to a global energy crisis. However, to date discoveries of new oil reserves have more than matched increased usage. In addition, there are factors which may extend or reduce this estimate, including the increasing demand for petroleum in developing nations, particularly China and India; further new discoveries; increased economic viability of recoveries from more difficult to exploit sources; energy conservation and use of alternative energy sources; and new economically viable exploitation of unconventional oil sources.
Formation
According to generally accepted theory, petroleum is derived from ancient biomass. The theory was initially based on the isolation of molecules from petroleum that closely resemble known biomolecules. More specifically, crude oil and natural gas are products of heating of ancient organic materials over geological time. Formation of petroleum occurs from hydrocarbon pyrolysis, in a variety of mostly endothermic reactions at high temperature and/or pressure. Today's oil formed from the preserved remains of prehistoric zooplankton and algae, which had settled to a sea or lake bottom in large quantities under anoxic conditions (the remains of prehistoric terrestrial plants, on the other hand, tended to form coal). Over geological time the organic matter mixed with mud, and was buried under heavy layers of sediment resulting in high levels of heat and pressure. This process caused the organic matter to change, first into a waxy material known as kerogen, which is found in various oil shales around the world, and then with more heat into liquid and gaseous hydrocarbons via a process known as catagenesis.
Geologists often refer to the temperature range in which oil forms as an "oil window"—below the minimum temperature oil remains trapped in the form of kerogen, and above the maximum temperature the oil is converted to natural gas through the process of thermal cracking. Although this temperature range is found at different depths below the surface throughout the world, a typical depth for the oil window is 4–6 km. Sometimes, oil which is formed at extreme depths may migrate and become trapped at much shallower depths than where it was formed. The Athabasca Oil Sands is one example of this.
Abiogenic Origin
A number of geologists in Russia adhere to the abiogenic petroleum origin hypothesis and maintain that hydrocarbons of purely inorganic origin exist within Earth's interior. Astronomer Thomas Gold championed the theory in the Western world by supporting the work done by Nikolai Kudryavtsev in the 1950s. It is currently supported primarily by Kenney and Krayushkin.
The abiogenic origin hypothesis lacks scientific support. Extensive research into the chemical structure of kerogen has identified algae as the primary source of oil. The abiogenic origin hypothesis fails to explain the presence of these markers in kerogen and oil, as well as failing to explain how inorganic origin could be achieved at temperatures and pressures sufficient to convert kerogen to graphite. It has not been successfully used in uncovering oil deposits by geologists, as the hypothesis lacks any mechanism for determining where the process may occur. More recently scientists at the Carnegie Institution for Science have found that ethane and heavier hydrocarbons can be synthesized under conditions of the upper mantle.
Crude Oil
Crude Oil Reservoirs
Three conditions must be present for oil reservoirs to form: a source rock rich in hydrocarbon material buried deep enough for subterranean heat to cook it into oil; a porous and permeable reservoir rock for it to accumulate in; and a cap rock (seal) or other mechanism that prevents it from escaping to the surface. Within these reservoirs, fluids will typically organize themselves like a three-layer cake with a layer of water below the oil layer and a layer of gas above it, although the different layers vary in size between reservoirs. Because most hydrocarbons are lighter than rock or water, they often migrate upward through adjacent rock layers until either reaching the surface or becoming trapped within porous rocks (known as reservoirs) by impermeable rocks above. However, the process is influenced by underground water flows, causing oil to migrate hundreds of kilometres horizontally or even short distances downward before becoming trapped in a reservoir. When hydrocarbons are concentrated in a trap, an oil field forms, from which the liquid can be extracted by drilling and pumping.
The reactions that produce oil and natural gas are often modeled as first order breakdown reactions, where hydrocarbons are broken down to oil and natural gas by a set of parallel reactions, and oil eventually breaks down to natural gas by another set of reactions. The latter set is regularly used in petrochemical plants and oil refineries.
Unconventional oil reservoirs
Oil-eating bacteria biodegrades oil that has escaped to the surface. Oil sands are reservoirs of partially biodegraded oil still in the process of escaping and being biodegraded, but they contain so much migrating oil that, although most of it has escaped, vast amounts are still present—more than can be found in conventional oil reservoirs. The lighter fractions of the crude oil are destroyed first, resulting in reservoirs containing an extremely heavy form of crude oil, called crude bitumen in Canada, or extra-heavy crude oil in Venezuela. These two countries have the world's largest deposits of oil sands.
On the other hand, oil shales are source rocks that have not been exposed to heat or pressure long enough to convert their trapped hydrocarbons into crude oil. Technically speaking, oil shales are not really shales and do not really contain oil, but are usually relatively hard rocks called marls containing a waxy substance called kerogen. The kerogen trapped in the rock can be converted into crude oil using heat and pressure to simulate natural processes. The method has been known for centuries and was patented in 1694 under British Crown Patent No. 330 covering, "A way to extract and make great quantityes of pitch, tarr, and oyle out of a sort of stone." Although oil shales are found in many countries, the United States has the world's largest deposits.
Classification
The petroleum industry generally classifies crude oil by the geographic location it is produced in (e.g. West Texas Intermediate, Brent, or Oman), its API gravity (an oil industry measure of density), and by its sulfur content. Crude oil may be considered light if it has low density or heavy if it has high density; and it may be referred to as sweet if it contains relatively little sulfur or sour if it contains substantial amounts of sulfur.
The geographic location is important because it affects transportation costs to the refinery. Light crude oil is more desirable than heavy oil since it produces a higher yield of gasoline, while sweet oil commands a higher price than sour oil because it has fewer environmental problems and requires less refining to meet sulfur standards imposed on fuels in consuming countries. Each crude oil has unique molecular characteristics which are understood by the use of crude oil assay analysis in petroleum laboratories.
Barrels from an area in which the crude oil's molecular characteristics have been determined and the oil has been classified are used as pricing references throughout the world. Some of the common reference crudes are:
• West Texas Intermediate (WTI), a very high-quality, sweet, light oil delivered at Cushing, Oklahoma for North American oil
• Brent Blend, comprising 15 oils from fields in the Brent and Ninian systems in the East Shetland Basin of the North Sea. The oil is landed at Sullom Voe terminal in the Shetlands. Oil production from Europe, Africa and Middle Eastern oil flowing West tends to be priced off this oil, which forms a benchmark
• Dubai-Oman, used as benchmark for Middle East sour crude oil flowing to the Asia-Pacific region
• Tapis (from Malaysia, used as a reference for light Far East oil)
• Minas (from Indonesia, used as a reference for heavy Far East oil)
• The OPEC Reference Basket, a weighted average of oil blends from various OPEC (The Organization of the Petroleum Exporting Countries) countries.
There are declining amounts of these benchmark oils being produced each year, so other oils are more commonly what is actually delivered. While the reference price may be for West Texas Intermediate delivered at Cushing, the actual oil being traded may be a discounted Canadian heavy oil delivered at Hardisty, Alberta, and for a Brent Blend delivered at the Shetlands, it may be a Russian Export Blend delivered at the port of Primorsk.
Overview
Petroleum (or crude oil) is a naturally occurring, flammable liquid found in rock formations in the Earth consisting of a complex mixture of hydrocarbons of various molecular weights, plus other organic compounds.
The term "petroleum" was first used in the treatise De Natura Fossilium, published in 1546 by the German mineralogist Georg Bauer, also known as Georgius Agricola.
Composition
In its strictest sense, petroleum includes only crude oil, but in common usage it includes both crude oil and natural gas. Both crude oil and natural gas are predominantly a mixture of hydrocarbons. Under surface pressure and temperature conditions, the lighter hydrocarbons methane, ethane, propane and butane occur as gases, while the heavier ones from pentane and up are in the form of liquids or solids. However, in the underground oil reservoir the proportion which is gas or liquid varies depending on the subsurface conditions, and on the phase diagram of the petroleum mixture,
An oil well produces predominantly crude oil, with some natural gas dissolved in it. Because the pressure is lower at the surface than underground, some of the gas will come out of solution and be recovered as associated gas or solution gas. A gas well produces predominately natural gas. However, because the underground temperature and pressure are higher than at the surface, the gas may contain heavier hydrocarbons such as pentane, hexane, and heptane in the gaseous state. Under surface conditions these will condense out of the gas and form natural gas condensate, often shortened to condensate. Condensate resembles gasoline in appearance and is similar in composition to some volatile light crude oils.
The proportion of hydrocarbons in the petroleum mixture is highly variable between different oil fields and ranges from as much as 97% by weight in the lighter oils to as little as 50% in the heavier oils and bitumens.
Crude oil varies greatly in appearance depending on its composition. It is usually black or dark brown (although it may be yellowish or even greenish). In the reservoir it is usually found in association with natural gas, which being lighter forms a gas cap over the petroleum, and saline water which, being heavier than most forms of crude oil, generally sinks beneath it. Crude oil may also be found in semi-solid form mixed with sand and water, as in the Athabasca oil sands in Canada, where it is usually referred to as crude bitumen.
Petroleum is used mostly, by volume, for producing fuel oil and gasoline (petrol), both important "primary energy" sources. 84% by volume of the hydrocarbons present in petroleum is converted into energy-rich fuels (petroleum-based fuels), including gasoline, diesel, jet, heating, and other fuel oils, and liquefied petroleum gas. The lighter grades of crude oil produce the best yields of these products, but as the world's reserves of light and medium oil are depleted, oil refineries are increasingly having to process heavy oil and bitumen, and use more complex and expensive methods to produce the products required. Because heavier crude oils have too much carbon and not enough hydrogen, these processes generally involve removing carbon from or adding hydrogen to the molecules, and using fluid catalytic cracking to convert the longer, more complex molecules in the oil to the shorter, simpler ones in the fuels.
Due to its high energy density, easy transportability and relative abundance, oil has become the world's most important source of energy since the mid-1950s. Petroleum is also the raw material for many chemical products, including pharmaceuticals, solvents, fertilizers, pesticides, and plastics; the 16% not used for energy production is converted into these other materials.
Petroleum is found in porous rock formations in the upper strata of some areas of the Earth's crust. There is also petroleum in oil sands (tar sands). Known reserves of petroleum are typically estimated at around 190 km3 (1.2 trillion (short scale) barrels) without oil sands, or 595 km3 (3.74 trillion barrels) with oil sands. Consumption is currently around 84 million barrels (13.4×106 m3) per day, or 4.9 km3 per year. Because the energy return over energy invested (EROEI) ratio of oil is constantly falling (due to physical phenomena such as residual oil saturation, and the economic factor of rising marginal extraction costs), recoverable oil reserves are significantly less than total oil in place. At current consumption levels, and assuming that oil will be consumed only from reservoirs, known recoverable reserves would be gone around 2039, potentially leading to a global energy crisis. However, to date discoveries of new oil reserves have more than matched increased usage. In addition, there are factors which may extend or reduce this estimate, including the increasing demand for petroleum in developing nations, particularly China and India; further new discoveries; increased economic viability of recoveries from more difficult to exploit sources; energy conservation and use of alternative energy sources; and new economically viable exploitation of unconventional oil sources.
Formation
According to generally accepted theory, petroleum is derived from ancient biomass. The theory was initially based on the isolation of molecules from petroleum that closely resemble known biomolecules. More specifically, crude oil and natural gas are products of heating of ancient organic materials over geological time. Formation of petroleum occurs from hydrocarbon pyrolysis, in a variety of mostly endothermic reactions at high temperature and/or pressure. Today's oil formed from the preserved remains of prehistoric zooplankton and algae, which had settled to a sea or lake bottom in large quantities under anoxic conditions (the remains of prehistoric terrestrial plants, on the other hand, tended to form coal). Over geological time the organic matter mixed with mud, and was buried under heavy layers of sediment resulting in high levels of heat and pressure. This process caused the organic matter to change, first into a waxy material known as kerogen, which is found in various oil shales around the world, and then with more heat into liquid and gaseous hydrocarbons via a process known as catagenesis.
Geologists often refer to the temperature range in which oil forms as an "oil window"—below the minimum temperature oil remains trapped in the form of kerogen, and above the maximum temperature the oil is converted to natural gas through the process of thermal cracking. Although this temperature range is found at different depths below the surface throughout the world, a typical depth for the oil window is 4–6 km. Sometimes, oil which is formed at extreme depths may migrate and become trapped at much shallower depths than where it was formed. The Athabasca Oil Sands is one example of this.
Abiogenic Origin
A number of geologists in Russia adhere to the abiogenic petroleum origin hypothesis and maintain that hydrocarbons of purely inorganic origin exist within Earth's interior. Astronomer Thomas Gold championed the theory in the Western world by supporting the work done by Nikolai Kudryavtsev in the 1950s. It is currently supported primarily by Kenney and Krayushkin.
The abiogenic origin hypothesis lacks scientific support. Extensive research into the chemical structure of kerogen has identified algae as the primary source of oil. The abiogenic origin hypothesis fails to explain the presence of these markers in kerogen and oil, as well as failing to explain how inorganic origin could be achieved at temperatures and pressures sufficient to convert kerogen to graphite. It has not been successfully used in uncovering oil deposits by geologists, as the hypothesis lacks any mechanism for determining where the process may occur. More recently scientists at the Carnegie Institution for Science have found that ethane and heavier hydrocarbons can be synthesized under conditions of the upper mantle.
Crude Oil
Crude Oil Reservoirs
Three conditions must be present for oil reservoirs to form: a source rock rich in hydrocarbon material buried deep enough for subterranean heat to cook it into oil; a porous and permeable reservoir rock for it to accumulate in; and a cap rock (seal) or other mechanism that prevents it from escaping to the surface. Within these reservoirs, fluids will typically organize themselves like a three-layer cake with a layer of water below the oil layer and a layer of gas above it, although the different layers vary in size between reservoirs. Because most hydrocarbons are lighter than rock or water, they often migrate upward through adjacent rock layers until either reaching the surface or becoming trapped within porous rocks (known as reservoirs) by impermeable rocks above. However, the process is influenced by underground water flows, causing oil to migrate hundreds of kilometres horizontally or even short distances downward before becoming trapped in a reservoir. When hydrocarbons are concentrated in a trap, an oil field forms, from which the liquid can be extracted by drilling and pumping.
The reactions that produce oil and natural gas are often modeled as first order breakdown reactions, where hydrocarbons are broken down to oil and natural gas by a set of parallel reactions, and oil eventually breaks down to natural gas by another set of reactions. The latter set is regularly used in petrochemical plants and oil refineries.
Unconventional oil reservoirs
Oil-eating bacteria biodegrades oil that has escaped to the surface. Oil sands are reservoirs of partially biodegraded oil still in the process of escaping and being biodegraded, but they contain so much migrating oil that, although most of it has escaped, vast amounts are still present—more than can be found in conventional oil reservoirs. The lighter fractions of the crude oil are destroyed first, resulting in reservoirs containing an extremely heavy form of crude oil, called crude bitumen in Canada, or extra-heavy crude oil in Venezuela. These two countries have the world's largest deposits of oil sands.
On the other hand, oil shales are source rocks that have not been exposed to heat or pressure long enough to convert their trapped hydrocarbons into crude oil. Technically speaking, oil shales are not really shales and do not really contain oil, but are usually relatively hard rocks called marls containing a waxy substance called kerogen. The kerogen trapped in the rock can be converted into crude oil using heat and pressure to simulate natural processes. The method has been known for centuries and was patented in 1694 under British Crown Patent No. 330 covering, "A way to extract and make great quantityes of pitch, tarr, and oyle out of a sort of stone." Although oil shales are found in many countries, the United States has the world's largest deposits.
Classification
The petroleum industry generally classifies crude oil by the geographic location it is produced in (e.g. West Texas Intermediate, Brent, or Oman), its API gravity (an oil industry measure of density), and by its sulfur content. Crude oil may be considered light if it has low density or heavy if it has high density; and it may be referred to as sweet if it contains relatively little sulfur or sour if it contains substantial amounts of sulfur.
The geographic location is important because it affects transportation costs to the refinery. Light crude oil is more desirable than heavy oil since it produces a higher yield of gasoline, while sweet oil commands a higher price than sour oil because it has fewer environmental problems and requires less refining to meet sulfur standards imposed on fuels in consuming countries. Each crude oil has unique molecular characteristics which are understood by the use of crude oil assay analysis in petroleum laboratories.
Barrels from an area in which the crude oil's molecular characteristics have been determined and the oil has been classified are used as pricing references throughout the world. Some of the common reference crudes are:
• West Texas Intermediate (WTI), a very high-quality, sweet, light oil delivered at Cushing, Oklahoma for North American oil
• Brent Blend, comprising 15 oils from fields in the Brent and Ninian systems in the East Shetland Basin of the North Sea. The oil is landed at Sullom Voe terminal in the Shetlands. Oil production from Europe, Africa and Middle Eastern oil flowing West tends to be priced off this oil, which forms a benchmark
• Dubai-Oman, used as benchmark for Middle East sour crude oil flowing to the Asia-Pacific region
• Tapis (from Malaysia, used as a reference for light Far East oil)
• Minas (from Indonesia, used as a reference for heavy Far East oil)
• The OPEC Reference Basket, a weighted average of oil blends from various OPEC (The Organization of the Petroleum Exporting Countries) countries.
There are declining amounts of these benchmark oils being produced each year, so other oils are more commonly what is actually delivered. While the reference price may be for West Texas Intermediate delivered at Cushing, the actual oil being traded may be a discounted Canadian heavy oil delivered at Hardisty, Alberta, and for a Brent Blend delivered at the Shetlands, it may be a Russian Export Blend delivered at the port of Primorsk.
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