Steam injection (oil industry)
Encyclopedia
Steam injection is an increasingly common method of extracting heavy oil
. 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 (USA), the Lake Maracaibo
area of Venezuela, and the oil sands of northern Alberta (Canada).
. Production will decrease as the oil cools down, and once production reaches an economically determined level the steps are repeated again.
The process can be quite effective, especially in the first few cycles. However, it is typically only able to recover approximately 20% of the Original Oil in Place (OOIP), compared to steam flooding, 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 was accidentally discovered by Shell
while it was doing a steam flood in Venezuela
and one of its steam injectors blew out and ended up producing oil
at much higher rates than a conventional production well in a similar environment.
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). Laricina claims that combining solvents with steam reduces the overall steam oil ratio for recovery by 30%.
Heavy oil
Heavy oil may refer to:*Fuel oil that contains residual oil left over from distillation.*Heavy crude oil, viscous crude oil.*Coal tar creosote, a wood preservative and waterproofing agent....
. It is considered an enhanced oil recovery
Enhanced oil recovery
Enhanced Oil Recovery is a generic term for techniques for increasing the amount of crude oil that can be extracted from an oil field...
(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
San Joaquin Valley
The San Joaquin Valley is the area of the Central Valley of California that lies south of the Sacramento – San Joaquin River Delta in Stockton...
of California (USA), the Lake Maracaibo
Lake Maracaibo
Lake Maracaibo is a large brackish bay in Venezuela at . It is connected to the Gulf of Venezuela by Tablazo Strait at the northern end, and fed by numerous rivers, the largest being the Catatumbo. It is commonly considered a lake rather than a bay or lagoon, and at 13,210 km² it would be the...
area of Venezuela, and the oil sands of northern Alberta (Canada).
Cyclic Steam Stimulation
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 temperature at which it flows. After it is decided enough steam has been injected, the steam is usually left to "soak" for some time after (typically not more than a few days). Then oil is produced out of the same well, at first by natural flow (since the steam injection will have increased the reservoir pressure) and then by artificial liftArtificial lift
Artificial lift refers to the use of artificial means to increase the flow of liquids, such as crude oil or water, from a production well. Generally this is achieved by the use of a mechanical device inside the well or by decreasing the weight of the hydrostatic column by injecting gas into the...
. Production will decrease as the oil cools down, and once production reaches an economically determined level the steps are repeated again.
The process can be quite effective, especially in the first few cycles. However, it is typically only able to recover approximately 20% of the Original Oil in Place (OOIP), compared to steam flooding, 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 was accidentally discovered by Shell
Royal Dutch Shell
Royal Dutch Shell plc , commonly known as Shell, is a global oil and gas company headquartered in The Hague, Netherlands and with its registered office in London, United Kingdom. It is the fifth-largest company in the world according to a composite measure by Forbes magazine and one of the six...
while it was doing a steam flood in Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
and one of its steam injectors blew out and ended up producing oil
Oil
An oil is any substance that is liquid at ambient temperatures and does not mix with water but may mix with other oils and organic solvents. This general definition includes vegetable oils, volatile essential oils, petrochemical oils, and synthetic oils....
at much higher rates than a conventional production well in a similar environment.
Steam Flooding
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
Steam assisted gravity drainage
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 are drilled into the oil reservoir, one a few metres above the other...
(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
Laricina Energy
Laricina Energy Ltd. is a private Canadian oil producing company engaged in exploration in North-Eastern Alberta. The company targets oil sands opportunities outside of the Athabasca mining area and is focusing on in situ plays in the Grosmont and Grand Rapids formations. Its headquarters are...
combined solvent injection with steam injection in a process called solvent cyclic steam-assisted gravity drainage (SC-SAGD). Laricina claims that combining solvents with steam reduces the overall steam oil ratio for recovery by 30%.