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Steam injection is an increasingly common method of extracting heavy crude oil. Used commercially since the 1960s, [1] it is considered an enhanced oil recovery (EOR) method and is the main type of thermal stimulation of oil reservoirs. There are several different forms of the technology, with the two main ones being Cyclic Steam Stimulation and Steam Flooding. Both are most commonly applied to oil reservoirs, which are relatively shallow and which contain crude oils which are very viscous at the temperature of the native underground formation. Steam injection is widely used in the San Joaquin Valley of California (US), the Lake Maracaibo area of Venezuela, and the oil sands of northern Alberta, Canada. [1]
Another contributing factor that enhances oil production during steam injection is related to near-wellbore cleanup. In this case, steam reduces the viscosity that ties paraffins and asphaltenes to the rock surfaces while steam distillation of crude oil light ends creates a small solvent bank that can miscibly remove trapped oil. [2]
This method, also known as the Huff and Puff method, consists of 3 stages: injection, soaking, and production. Steam is first injected into a well for a certain amount of time to heat the oil in the surrounding reservoir to a recover approximately 20% of the original oil in place (OOIP), compared to steam assisted gravity drainage, which has been reported to recover over 50% of OOIP. It is quite common for wells to be produced in the cyclic steam manner for a few cycles before being put on a steam flooding regime with other wells.
The mechanism proceeds through cycles of steam injection, soak, and oil production. First, steam is injected into a well at a temperature of 300 to 340° Celsius for a period of weeks to months. Next, the well is allowed to sit for days to weeks to allow heat to soak into the formation. Finally, the hot oil is pumped out of the well for a period of weeks or months. Once the production rate falls off, the well is put through another cycle of injection, soak and production. This process is repeated until the cost of injecting steam becomes higher than the money made from producing oil. [3] The CSS method has the advantage that recovery factors are around 20 to 25% and the disadvantage that the cost to inject steam is high.
Canadian Natural Resources use "employs cyclic steam or "huff and puff" technology to develop bitumen resources. This technology requires one well bore and the production consists of the injection and production phases. First steam is "injected for several weeks, mobilizing cold bitumen". Then the flow "on the injection well is reversed producing oil through the same injection well bore. The injection and production phases together comprise one cycle. "Steam is re-injected to begin a new cycle when oil production rates fall below a critical threshold due to the cooling of the reservoir. Artificial lift method of production may be used at this stage. After a few cycles, it may not be economical to produce by the huff and puff method. Steam flooding is then considered for further oil recovery if other conditions are favorable. It has been observed that recovery from huff and puff can be achieved up to 30% and from steam flooding recovery can be up to 50%" ( CNRL 2013 ) . [4]
In a steam flood, sometimes known as a steam drive, some wells are used as steam injection wells and other wells are used for oil production. Two mechanisms are at work to improve the amount of oil recovered. The first is to heat the oil to higher temperatures and to thereby decrease its viscosity so that it more easily flows through the formation toward the producing wells. A second mechanism is the physical displacement employing in a manner similar to water flooding, in which oil is meant to be pushed to the production wells. While more steam is needed for this method than for the cyclic method, it is typically more effective at recovering a larger portion of the oil.
A form of steam flooding that has become popular in the Alberta oil sands is steam assisted gravity drainage (SAGD), in which two horizontal wells are drilled, one a few meters above the other, and steam is injected into the upper one. The intent is to reduce the viscosity of the bitumen to the point where gravity will pull it down into the producing well.
In 2011 Laricina Energy combined solvent injection with steam injection in a process called solvent cyclic steam-assisted gravity drainage (SC-SAGD) ( Canadian Association of Petroleum Producers CAPP 2009 ) . [5] Laricina claims that combining solvents with steam reduces the overall steam oil ratio for recovery by 30%.
The alternative to surface generated steam is downhole steam generation that reduces heat loss and generates high-quality steam in the reservoir that allows for more heavy oil and oil sands production at a faster rate. Downhole steam generators were first proposed by the major oil companies in the early 1960s. Over the last 50 years multiple downhole steam technologies have been developed such as the DOE and SANDIA downhole combustion system known as Project Deep Steam that was field tested in Long Beach, CA in 1982, but was a failure. The only downhole steam generator that has proved successful is branded as eSteam[ citation needed ].
Oil sands, tar sands, crude bitumen, or bituminous sands, are a type of unconventional petroleum deposit. Oil sands are either loose sands or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and water, soaked with bitumen, a dense and extremely viscous form of petroleum.
The Athabasca oil sands, also known as the Athabasca tar sands, are large deposits of bitumen or extremely heavy crude oil that constitute unconventional resources, located in northeastern Alberta, Canada – roughly centred on the boomtown of Fort McMurray. These oil sands, hosted primarily in the McMurray Formation, consist of a mixture of crude bitumen, silica sand, clay minerals, and water. The Athabasca deposit is the largest known reservoir of crude bitumen in the world and the largest of three major oil sands deposits in Alberta, along with the nearby Peace River and Cold Lake deposits.
Heavy crude oil is highly viscous oil that cannot easily flow from production wells under normal reservoir conditions.
Enhanced oil recovery, also called tertiary recovery, is the extraction of crude oil from an oil field that cannot be extracted otherwise. Although the primary and secondary recovery techniques rely on the pressure differential between the surface and the underground well, enhanced oil recovery functions by altering the chemical composition of the oil itself in order to make it easier to extract. EOR can extract 30% to 60% or more of a reservoir's oil, compared to 20% to 40% using primary and secondary recovery. According to the US Department of Energy, carbon dioxide and water are injected along with one of three EOR techniques: thermal injection, gas injection, and chemical injection. More advanced, speculative EOR techniques are sometimes called quaternary recovery.
Steam-assisted gravity drainage is an enhanced oil recovery technology for producing heavy crude oil and bitumen. It is an advanced form of steam stimulation in which a pair of horizontal wells is drilled into the oil reservoir, one a few metres above the other. High pressure steam is continuously injected into the upper wellbore to heat the oil and reduce its viscosity, causing the heated oil to drain into the lower wellbore, where it is pumped out. Dr. Roger Butler, engineer at Imperial Oil from 1955 to 1982, invented the steam assisted gravity drainage (SAGD) process in the 1970s. Butler "developed the concept of using horizontal pairs of wells and injected steam to develop certain deposits of bitumen considered too deep for mining". In 1983 Butler became director of technical programs for the Alberta Oil Sands Technology and Research Authority (AOSTRA), a crown corporation created by Alberta Premier Lougheed to promote new technologies for oil sands and heavy crude oil production. AOSTRA quickly supported SAGD as a promising innovation in oil sands extraction technology.
Connacher Oil and Gas Limited is a Calgary-based exploration, development and production company active in the production and sale of bitumen in the Athabasca oil sands region. Connacher's shares used to trade on the Toronto Stock Exchange, but it was de-listed in 2016, after filing for insolvency.
Carbon dioxide (CO2) flooding is a process in which carbon dioxide is injected into an oil reservoir to increase the output when extracting oil. This is most often used in reservoirs where production rates have declined due to depletion.
Petroleum is a fossil fuel that can be drawn from beneath the earth's surface. Reservoirs of petroleum are formed through the mixture of plants, algae, and sediments in shallow seas under high pressure. Petroleum is mostly recovered from oil drilling. Seismic surveys and other methods are used to locate oil reservoirs. Oil rigs and oil platforms are used to drill long holes into the earth to create an oil well and extract petroleum. After extraction, oil is refined to make gasoline and other products such as tires and refrigerators. Extraction of petroleum can be dangerous and have led to oil spills.
Canada's oil sands and heavy oil resources are among the world's great petroleum deposits. They include the vast oil sands of northern Alberta, and the heavy oil reservoirs that surround the small city of Lloydminster, which sits on the border between Alberta and Saskatchewan. The extent of these resources is well known, but better technologies to produce oil from them are still being developed.
The Alberta Oil Sands Technology and Research Authority (AOSTRA) was an Alberta crown corporation to promote the development and use of new technology for oil sands and heavy crude oil production, and enhanced recovery of conventional crude oil. It was funded by the Alberta Heritage Savings Trust Fund. Its head office and information centre were located in Edmonton, Alberta and a second office in Calgary, Alberta in Canada.
The Clearwater Formation is a stratigraphic unit of Early Cretaceous (Albian) age in the Western Canada Sedimentary Basin in northeastern Alberta, Canada. It was first defined by R.G. McConnell in 1893 and takes its name from the Clearwater River near Fort McMurray.
The McMurray Formation is a stratigraphic unit of Early Cretaceous age of the Western Canada Sedimentary Basin in northeastern Alberta. It takes the name from Fort McMurray and was first described from outcrops along the banks of the Athabasca River 5 kilometres (3.1 mi) north of Fort McMurray by F.H. McLearn in 1917. It is a well-studied example of fluvial to estuarine sedimentation, and it is economically important because it hosts most of the vast bitumen resources of the Athabasca Oil Sands region.
Heavy oil production is a developing technology for extracting heavy oil in industrial quantities. Estimated reserves of heavy oil are over 6 trillion barrels, three times that of conventional oil and gas.
Petrobank was an oil exploration, development, and production company based in Calgary, Canada. It operates through 4 units/subsidiaries, PetroBakken Energy in Canada, Petrominerales Ltd in Peru and Colombia, HBU in the heavy crude oil business, and its technology unit Archon Technologies Ltd . In 1986 the company changed its name from Petrobank Energy Resources Ltd. to Petrobank Energy and Resources Ltd. Though it has a significant resource base its ten patents for heavy oil extracting technology are becoming increasingly valuable to the company. In December 2010 the company received permission from the government of Alberta to produce oil sands bitumen at a new location in Dawson using a technique known as fireflooding, the third Petrobank operation that will use it; the 50% interest in Dawson was acquired in October from Shell Canada.
The Long Lake oil sands upgrader project is an in situ oil extraction project near Anzac, Alberta, 40 km (25 mi) southeast of Fort McMurray in the Athabasca oil sands region of Alberta.
Laricina Energy Ltd. was a private Canadian oil producing company engaged in exploration in North-Eastern Alberta. The company targeted oil sands opportunities outside of the Athabasca mining area and was focusing on in situ plays in the Grosmont and Grand Rapids formations. Its headquarters were located in Calgary, Alberta, Canada.
Located in northwest-central Alberta, the Peace River oil sands deposit is the smallest of four large deposits of oil sands of the Western Canadian Sedimentary Basin formation.
The Underground Test Facility (UTF) site is located approximately 60 km Northwest of Fort McMurray. In the 1980s, Alberta Oil Sands Technology and Research Authority (AOSTRA) initiated an extensive program to evaluate horizontal well recovery processes for Steam-assisted gravity drainage (SAGD) deep oil recovery from shafts and tunnels (Shaft and Tunnel Access Concept – SATAC. The SAGD process which developed in the late 80s included drilling wells in pairs with the producer at the base of the reservoir and the steam injector from the above. The top well injects heat into the reservoir to form a steam chamber and makes the bitumen more liquid which then drains to the production well. The UTF site contains an oil reservoir 20 meters thick. It was determined that these reserves could be mined from tunnels in the limestone below the pay zone using SAGD.
Riyaz Kharrat is an eminent Iranian scientist in the field of chemical engineering and petroleum engineering. He is a full professor at Montanuniversität Leoben.
Carabobo is an oil field located in Venezuela's Orinoco Belt. As one of the world's largest accumulations of recoverable oil, the recent discoveries in the Orinoco Belt have led to Venezuela holding the world's largest recoverable reserves in the world, surpassing Saudi Arabia in July 2010. The Carabobo oil field is majority owned by Venezuela's national oil company, Petroleos de Venezuela SA (PDVSA). Owning the majority of the Orinoco Belt, and its estimated 1.18 trillion barrels of oil in place, PDVSA is now the fourth largest oil company in the world. The field is well known for its extra Heavy crude oils, having an average specific gravity between 4 and 16 °API. The Orinoco Belt holds 90% of the world's extra heavy crude oils, estimated at 256 billion recoverable barrels. While production is in its early development, the Carabobo field is expected to produce 400,000 barrels of oil per day.
Oil sands operators are exploring the use solvents with steam-assisted gravity drainage (SAGD) to help loosen and extract bitumen. Laricina Energy CEO Glen Schmidt likens the technology to a hybrid car