Study on distribution laws of gas-bearing property of coal seams and geological control factors in Hancheng Mining Area

In order to find out the difference of production characteristics between single wells in Hancheng Mining Area, based on the gas-bearing property of main coal seams of Hancheng Mining Area, the geological control factors were discussed in the paper, such as coal rank, coal maceral, geologic structures, and hydrogeologi cal conditions, which has influence on the gas-bearing property.The results showed that the gas-bearing property of main coal seams had two typical characteristics: on the one hand, the gas-bearing property of No.11 coal seam of Taiyuan Formation was better than that of No. 3 and No.5 coal seam of Shanxi Formation, which was clo sely related with the depth of coal seam and the sedimentary environment; The gas saturation of each coal seam was 25% ~ 94%, with an average value of 63%, with t he burial depth increasing, the gas saturation of each coal seam varied lttle, but it showed an increasing trend in general.The reason was that the coal reservoir in this area was under pressure reservoir, and it had not reached the critical point of the difference of the adsorption behavior of different coal and rock. It was also found that with the increase of metamorphic degree of coal and rock and the increase of vitrinite contentin this block, gas content and adsorption all increased, which was conside red to concrete manifestation of the geological effect of coalbed methane controlled by the two coalifications; The gas content of coal bed was obviously controlled by t he structural conditions and hydrogeological conditions.