Study on enrichment law and development features of deep coalbed methane in South Yanchuan Field

In order to summarize the geological characteristics and production rules of deep coalbed methane in South Yanchuan Field,a study was conducted on the enrichment law and the gas production characteristics as well as the differences existed in the shallow depth coalbed methane. The results showed that the major enrichment and high production factors of the coalbed methane in the south deep part of Yanchuan were the sedimentary coal control, the tectonic-hydrogeology combined gas control and physical property control. From the desorption mechanism of the coalbed methane, the gas drainage rate reduced, the gas seepage period and the pressure released volume improved gas drainage method could ensure the high production and stable production of the deep coalbed methane well. The trial drainage normalized results of the well group showed that the initial desorption efficiency of the deep coalbed methane was low, but the controlled reserves of a single well was high with the “delayed gas production, slow production, long stable production and high production” features. The high production and stable production results of deep coalbed methane in South Yanchuan Field showed that such kind gas reservoir would have the feasibility of the beneficial development and the study results could provide experience for the exploration and development of the similar gas reservoirs.