Evaluation of Favorable Area in the Weibei Coalbed Methane Field: a Study by Using Grey Correlation Analysis

Based on the gas analysis results of coalbed methane (CBM) wells in the Weibei CBM field, two main recoverable target seams (Nos. 5 and 11) were evaluated for the potential of exploration and exploitation by using the grey correlation analysis method. The main influnce factors on the CBM potential by increasing importance are gas content, gas saturation, buried depth, methane concentration, critical desorption pressure,reservoir pressure and coal thickness for the No.5 coal seam; while they are gas saturation, gas content, critical desorption pressure, methane concentration, buried depth, reservoir pressure and coal thickness for the No.11 coal seam. The exploration potential of No.5 coal seam is better than that of No.11. The favorable area for CBM exploration are the areas including Well block W2, W3, W4 and W8 in the middle of Weibei CBM field.