Experimental investigation of CO2 injection into coal seam reservoir at in-situ stress conditions for enhanced coalbed methane recovery (original) (raw)

Generally, Secondary recovery in fractured reservoir expected to be lower than conventional reservoir due to permeability heterogeneity. In these reservoirs, fluids are conducted to the production well by fractures, therefore considerable amount of oil will trapped in the matrix. The trapped oil could be produced by cross flows or mass transfer from the bypassed region. In this work, CO 2 injection is studied in first contact miscible, near miscible and immiscible condition of flow through matrix-fracture system. The aim of the conducted experiments is to investigate the performance of CO 2 injection into the carbonated fractured reservoirs. During the experiments cores are saturated by decane and CO 2 is injected through the fractures. The results of experiments show that the highest rate of recovery is obtained during the near miscible co2 injection flood. Where, 63 percent of trapped oil is recovered. At the same time the recovery factor of the first contact miscible and immiscible conditions are 36 and 8 percent respectively.