News | May 25, 2007

Carbon Sequestration Field Test Begins In Illinois Basin

Washington, DC - The Midwest Geological Sequestration Consortium (MGSC), one of seven regional partnerships created by the Department of Energy in 2002 to advance carbon sequestration technologies, is conducting its first enhanced oil recovery field test in the Loudon Field in Illinois. Teaming geologic sequestration with enhanced oil recovery could significantly boost oil production while employing one of the most promising strategies for cutting greenhouse gas emissions.

The test is evaluating the potential for geologic sequestration in mature Illinois oil reservoirs as part of an enhanced oil recovery program. In enhanced oil recovery (EOR), a gas, heat, or chemical is added to a reservoir to increase oil production, primarily by increasing temperature or pressure, or by lowering the oil's viscosity, which improves its ability to flow through the reservoir. Enhanced oil recovery using CO2 (CO2-EOR) can significantly boost short-term oil production and generate quick payouts, especially when oil prices are favorable. These treatments benefit small lease operators who otherwise cannot afford the cost associated with exploiting these reservoirs.

In addition to the merits of CO2-EOR for enhancing our nation's domestic oil supply, the successful results of this project also help demonstrate that geologic sequestration is a safe and permanent method to mitigate our greenhouse gas emissions. In geologic sequestration, CO2 is stored underground in rock formations. The formations are chosen based on their attributes and location: layers of porous rock deep underground that are capped by a layer of impermeable rock above are ideal candidates. Once a site is chosen, a well is drilled into the porous rock and pressurized CO2 is injected into it. The buoyant CO2 flows up until it encounters the non-porous cap and is effectively trapped.

The Louden field test, an enhanced oil recovery "huff-n-puff" project, is designed to inject (huff) CO2 into a producing well for 3-5 days, allow the gas to soak for approximately a week, then place the well back on production and measure the amount of fluids produced (puff). MGSC researchers successfully injected 45 tons of CO2 gas into a producing oil well in March. After the 1-week soak period, daily oil production initially increased fourfold, but subsequently decreased. Depending on post-injection results, another CO2 injection period may take place in this well. Currently, the project is determining the amount of injected CO2 that remains in the oilfield.

The test is part of the validation phase of the Department of Energy's Regional Carbon Sequestration Partnerships program, which is managed by the Office of Fossil Energy's National Energy Technology Laboratory. During this phase, field tests will validate the most promising sites to deploy sequestration technologies. The sites were initially chosen during a characterization phase that ended in June of 2005. Louden Field, in Fayette County, Ill., was chosen from a list of 38 nominated sites. The site is rural, flat agricultural land that been part of an existing oil field for more than 65 years.

SOURCE: The Midwest Geological Sequestration Consortium