Systematic Division of Coalbed Methane-Enriched Units

Division of coalbed methane (CBM)-enriched units primarily depends on the analysis of the main controlling factors of CBM occurrence. The main controlling factors analyzed in this article are sedimentary sequences related to the forming and alteration of CBM, tectonic movement, and burial and hydrocarbon-generation histories. The parameters were measured for independent quantities such as CBM content, gradient, coefficient of extraction difficulty and geological structure complexity. Correlation analysis was conducted between the measured parameters of CBM-bearing systems and the main controlling factors. When the controlling factors are sedimentary sequences and the sedimentary systems tract, the division of CBM-enriched units is based on the coal-forming environment, coal mass distribution and coal characteristics. When the controlling factor is the tectonic matching between the orefield, mining area and mining wells, the division of CBM-enriched units is based on tectonic movement. When burial and hydrocarbon-generation histories are the controlling factors, the division of CBM-enriched units is based on metamorphic traits.