Coalbed methane reservoir formation history and its geological control at the Shuigonghe Syncline

Abstract

Coalbed methane (CBM) commercial developments have made breakthroughs in a few areas in China, including Qinshui Basin and Ordos Basin. For years, Eastern Yunnan Province and Western Guizhou Province have been the new hot spots of CBM study in China. Predecessors have discussed CBM reservoir characteristics, CBM system, and geological process evolution. Basing on previous research, we studied the formation history of the CBM reservoir by numerical simulation at the Shuigonghe Syncline in Western Guizhou. Data were obtained from geological survey and laboratory testing. According to the simulation results, the CBM reservoir formation history can be divided into five stages. In addition, a plane distributive contour map of CBM reservoir formation-related data was constructed to recognize the change in CBM content and CBM dissipation quality at different stages in the region. Each stage has its feature on CBM generation, dissipation, and accumulation speed. Geological process controlling factors, including burial history, tectonic history, geothermal history, and maturation, were analyzed. All factors acted together and formed the CBM reservoir in the Shuigonghe Syncline. Among these factors, tectonic evolution history is the most important because it determines the whole generation–preservation–dissipation process of CBM. The other factors affect the process in various ways.