Reservoir engineering aspects of CO_2 sequestration in coals

摘要

With increasing worldwide CO_2 emissions, interest has risen in injecting CO_2 into coals to mitigate their possible role in global warming. Concepts from natural gas storage are readily adapted to CO_2 sequestration in coals. The classic p/Z plot for describing stored gas inventories is modified for CO_2 sequestration using the p/Z* concept developed for understanding conventional coal gas recovery. Coal often exhibits stress dependent permeability and this relationship is used to identify the optimal depth for CO_2 injection. CO_2 fillup of a coal seam is described by coupling a gas injectivity equation with a mass balance equation. Example calculations are presented for two selected basins.