3 Methods To Enhance Oil Recovery

​Primary, secondary, and tertiary (or improved) recovery are three separate phases of crude oil development and production in US oil reservoirs. During primary recovery, the reservoir's natural pressure or gravity force oil into the wellbore, which is then brought to the surface using artificial lift techniques (such as pumps). During primary recovery, however, only approximately 10% of a reservoir's initial oil in place is ​normally generated. Secondary recovery procedures mainly include pumping water or gas into a field to displace oil and drive it to a production wellbore, resulting in the recovery of 20 to 40% of the original oil in place.
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However, because much of the easy-to-produce oil has already been collected from U.S. oil fields, producers have tried a number of tertiary, or enhanced oil recovery (EOR), techniques that promise to recover 30 to 60 percent or more of the reservoir's original oil. To varied degrees, three key categories of EOR have been shown to be financially successful:

The introduction of heat, such as steam injection, to lower the viscosity, or thin, the heavy viscous oil, and improve its capacity to flow through the reservoir is known as thermal recovery. Thermal approaches account for more than 40% of EOR generation in the United States, especially in California.

Gas injection is a technique that involves injecting gases such as natural gas, nitrogen, or carbon dioxide (CO2) into a reservoir. to inject more oil into a production wellbore, or other gases that dissolve in the oil to reduce viscosity and increase flow rate In the United States, gas injection contributes for roughly 60% of EOR output.

Chemical injection, which can include the use of long-chained molecules known as polymers to improve the effectiveness of waterfloods or detergent-like surfactants to help lower the surface tension that stops oil droplets from migrating through a reservoir. Chemical approaches account for around 1% of EOR generation in the United States.

Each of these methods has been limited by its relatively high cost and, in some situations, its unpredictable effectiveness.

There are around 114 active commercial CO2 injection projects in the United States. Over 2 billion cubic feet of CO2 are injected, resulting in over 280,000 BOPD (April 19, 2010, Oil and Gas Journal).

CO2 Injection Has a Lot of Potential Benefits

CO2-EOR is the EOR technology that is generating the most fresh commercial interest. CO2 injection has been effectively employed throughout the Permian Basin of West Texas and eastern New Mexico, and is now being pursued to a limited extent in Kansas, Mississippi, Wyoming, Oklahoma, Colorado, Utah, Montana, Alaska, and Pennsylvania. It was first tried in 1972 in Scurry County, Texas.

Until recently, the majority of CO2 for EOR came from naturally existing reservoirs. However, new technologies are being developed to manufacture CO2 from industrial applications such natural gas processing, fertilizer, ethanol, and hydrogen plants in places where naturally occurring CO2 is not available.There are no reservoirs available. One demonstration at the Dakota Gasification Company's plant in Beulah, North Dakota, produces CO2 and transports it to the Weyburn oil field in Saskatchewan, Canada, through a 204-mile pipeline. The CO2 injection is being done by Encana, the field's operator, in order to extend the field's productive life by another 25 years and potentially 130 million barrels of oil that would otherwise be abandoned.

CO2 Enhanced Oil Recovery: The Next Generation

The DOE's research and development program is expanding into new areas, looking into novel techniques that could improve CO2 injection's economic performance and expand its applicability to a larger group of reservoirs, taking the technique out of the Permian Basin in West Texas and Eastern New Mexico and into basins much closer to home.

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