Research on prediction method of coal seam gas content based on geological division

ZHANG Chongchong; WANG Yanbin; NI Xiaoming

Abstract：In order to accurately predict the gas content in coal seam,and to solve the problem of poor applicability and low accuracy of conventional logging interpretation methods,a method to district forecast the gas content in coal seam was proposed based on the difference of geological factors on the gas bearing property.First,according to a large number of laboratory test data,the influence of different sedimentary,tectonic and hydrodynamic conditions on the gas bearing properties of coal seams was analyzed and main control factors were obtained.Secondly,according to the fuzzy analytic hierarchy process,the difference of geological factors were quantified,and geological division was realized.Method of principal component analysis in each partition was introduced,fully used of a large number of conventional logging curves,and the prediction model of gas content in coal seam was established according to multivariate regression.The No.3 coal seam in southern area of Shizhuang was calculated as the research object the results show that the gas bearing properties were comprehensively influenced of various geological factors,and roof mudstone thickness,tectonic stress type,mineralization degree on plane,and controlled by fixed carbon content changing vertically.The fitting rate between division regression predictive value and measured value is 89％,the accuracy is fundamentally improved compared with the fitting rate 17％ of the conventional regression prediction.