Study On Critical Desorption Pressure Of Main Coal Reservoirs In Zhuzang Synline, Western Guizhou

Taking Zhuzang syncline as the research object in this paper, the adsorption-desorption characteristics of coal reservoir and critical desorption pressure distribution characteristics in different CBM systems were studied, which based on massive geological exploration information of coal resource and CBM wells of study area and experimental test data. Finally, we identified the main control factors of critical desorption pressure in different CBM systems, built model GM(0,5) and predicted the critical desorption pressure of 16, 23 coal seams.The main minable coals of different CBM systems had strong adsorption capacity in the study area. In vertical direction, the VL and PL showed wavy changes; the critical desorption pressure distribution of No.16 were varied. In the plane, the distribution law of critical desorption pressure of No.16 were same withgas-bearingcharacteristics. Through comprehensive analysis, it was believed that the critical desorption pressure was controlled by macroscopic factors like sedimentary environment and microscopic factors like coal composition. The microscopic was restricted by macroscopic, the mutual coupling of them controlled the gas-bearingcharacteristics and adsorption characteristics of coal reservoir. At the same time, the critical desorption pressure were also affected by experimental conditions. Three factors determined the critical desorption pressure together.Grey system theory was applied to calculate the correlation degree of control factors of critical desorption pressure in different CBM systems, the result showed that buried depth and coal reservoir pressure had greater effect on critical desorption pressure of three CBM systems, while other factors only had great influence on individual system. We selected 5 highest correlation degree of different CBM system and established GM(0,5) model for critical desorption pressure prediction. The prediction results conformed to the requirements of the precision and the general law of the region, and it showed that the GM(0,5) model was suitable for critical desorption pressure prediction of different CBM systems in the study area.