The influence of tectonic evolution on the accumulation and enrichment of coalbed methane (CBM)

The current accumulation and enrichment of CBM reservoir is a result of the preservation and destruction of former CBM, after the superposing evolution of reversing-and-uplifting and the subsequent evolution within the coal-bearing basin. The critical moment of the CBM reservoir formation is the time when the burying depth of the overlying net thickness amounts to the least in geological history after the gas generation of coal beds. Except the coal-bearing basins of lower metamorphism, most basins suffered the evolution stage of reversion and uplift. The formation of the CBM reservoir is controlled by the beginning and lasting time, and the intensity of reversing and uplifting. The tectonic evolution after reversing and uplifting also affects the accumulation of CBM in coal-bearing basin. The CBM constantly dissipates in the area of chronically uplifting and de-nudating. The area developed overlying sedimentation is advantageous to the preservation of CBM, but also can lead to the reduction of CBM saturation.