Comprehensive analysis of CBM recovery in high rank coal reservoir of Jincheng area

Coalbed methane (CBM) predicting recovery in high rank coal reservoir varies greatly in Jincheng area and it seriously influences efficient and economic exploitation of CBM resource. In order to predict more accurate CBM recovery, we conducted history matching and productivity prediction of vertical well by using COMET 3 reservoir modeling software, innovatively adopted the gas desorption experiment of bulk coal at fixed test pressure, analyzed the recovery extent method of Daning multiple-hole horizontal well and Panzhuang well group, and calculated recovery by sorption isotherm method of 14 vertical CBM wells at the abandonment pressures 1.0, 0.7, 0.5 and 0.3 MPa, respectively. The results show that the reservoir simulation methods (numerical simulation method and the recovery extent method) is more reliable than the theoretical analysis of coal sample (sorption isotherm method and desorption experiment method). Also, desorption experiment method at fixed pressure is superior to sorption isotherm method. Through the comprehensive analysis and linear correction, CBM recovery ratios in high rank coal reservoir of Jincheng area were found to be 38.64%, 49.30%, 59.30%, and 69.20% at the abandonment pressures 1.0, 0.7, 0.5 and 0.3 MPa, respectively. The research results are of significant importance in the CBM exploration and development in Jincheng area.