Simulating carbon dioxide sequestration/ECBM production in coal seams: Effects of coal properties and operational parameters

CO₂ sequestration is a promising technology for reducing anthropogenic greenhouse gas emissions while fossil fuels are still being used. CO₂ preferentially sorbs to coal, displacing methane, making CO₂-enhanced coalbed methane production an ideal candidate for CO₂ sequestration. PSU-COALCOMP, a dual-porosity coalbed methane simulator, was used to model primary and secondary production of methane from coal, for a variety of coal properties and operational parameters. Primary production of methane and water was simulated until a specified reservoir pressure was reached, after which CO₂ is injected in the center wells to displace methane, extending the reservoir's production of methane. Production continued until the CO₂ concentration in the produced gas was too high. The higher the injection well pressure, the more CO₂ could be absorbed to the coal, however, higher pressures decreased the sweep efficiency, causing large portions of the coal seam never to come in contact with CO₂. This is an abstract of a paper presented at the SPE Eastern Regional Meeting (Canton, OH 10/17-19/2001).