A strategy for prevention of sequestered carbon dioxide seepage from CBM formations.

摘要

This study introduces a new strategy for the prevention of post-sequestration carbon dioxide (CO2) seepage to the surface from CBM (coalbed methane) formations that is named the "Nature's Sequestration Technique" or "NST." The objective is to sequester CO2 in a CBM formation for an extensive time period (thousands of years), filling the coal cleat system with formation water.; Using a commercial numerical simulator and representative data of the Appalachian basin, we investigated whether or not the presence of water in the cleats helps to sequester CO2 in a coalbed for a long period of time without significant seepage. Different scenarios were evaluated with variations in depth, flow mechanism, and nature of fracture that would work as a conduit for seepage to the surface. A significant reduction in the amount of CO2 seeped to superjacent formations was observed when water fills the cleat system, which is favorable to maintaining CO2 adsorbed on the coal matrix.