Productivity of coalbed methane wells in southern of Qinshui Basin

Based on regional CBM geological characteristics and drainage data of three typical Coalbed Methane (CBM) wells in the southern Qinshui Basin, history matching, productivity prediction and factor analysis of gas production control are conducted by using COMET3 reservoir modeling software. The results show that in the next 20 years, the cumulative and average daily gas production of the QN01 well are expected to be 800×104 m3 and 1141.1 m3/d, for the QN02 well 87×104 m3 and 1202.7 m3/d and 97.5×104 m3 and 133.55 m3/d for the QN03 well. Gas content and reservoir pressure are the key factors controlling gas production in the area; coal thickness, permeability and porosity are less important; the Langmuir volume, Langmuir pressure and adsorption time have relatively small effect. In the process of CBM recovery, the material source and driving force are the key features affecting gas productivity, while the permeation process is relatively important and the desorption process has some impact on gas recovery.