Carbon Sequestration and Enhanced Recovery Potential of Mature Coalbed Methane Reservoirs in the Black Warrior Basin

Abstract

Mature coalbed methane reservoirs are prospective as major sinks for anthropogenic CO 2, and injection of CO 2shows promise for increasing coalbed methane reserves through enhanced recovery. Assessment of the carbon sequestration and enhanced recovery potential of coal in the Black Warrior basin indicates that numerous geological variables, including stratigraphy, structure, hydrology, geothermics, and coal quality, have a strong impact on the quantity of carbon that can be sequestered. Key variables affecting the feasibility of sequestration and enhanced recovery in the Black Warrior basin include (1) the distribution of mineable coal, (2) the distribution of formation water saline enough for underground injection, and (3) the distribution of structural compartments with sufficient reservoir continuity to host multiple five-spot well patterns. Within the developed coalbed methane fields, the feasible CO 2sequestration potential is estimated to be 166 Bscm (5.9 Tscf), or 341 MMt, which can facilitate long-term sequestration of CO 2emissions from coal-fired power plants. The potential for enhanced coalbed methane recovery in this area is estimated to be between 16 and 30 Bscm (0.6 and 1.1 Tscf), and realization of this potential would expand proven coalbed methane reserves by more than 30%.