PROCESS FOR RECOVERING METHANE AND/OR SEQUESTERING FLUIDS IN COAL BEDS

摘要

A process for recovering methane from a coal bed and/or sequestering a fluid more strongly adsorbing than methane ("SAG") in a coal bed involves fracturi ng an injection well and cyclically injecting SAG with intervening shut-in periods. Even though the absolute permeability of the coal bed decreases wit h continued SAG sorption, the SAG injectivity, surprisingly and unexpectedly, increases while injecting SAG at pressures greater than reservoir pressure, but less than fracture pressure or fracture extension pressure. The increase d injectivity is thought to be due to a reduction in near-well flow resistance .