RESERVOIR CHARACTERISTICS AND ENRICHMENT MECHANISM OF THE COAL-BED GAS IN THE NORTH OF QINSHUI BASIN

Coalbed methane(CBM)enrichment depends on the reservoir's characteristics,and it is also controlled by geologic setting.On the basis of detailed study on the reservoir's characteristics and CBM enrichment mechanism,the favorable exploitation prospect in the north of Qinshui Basin is demonstrated.The observation and test for the type,quality and structure of coal as well as the porosity,permeability and adsorbability show that the coal bed in this area is characterized by thick reservoir,high thermal evolution,local structural coal,devoloped fracture,high adsorbability,high gas content and low gas saturation.In one word,the research area fits for CBM exploitation.The CBM enrichment in the research area is controlled by thermal evolution history and burial history.Owing to magma thermal metamorphism superimposing on the regional metamorphosis,the intensity of gas generation is higher.Moreover,the burial depth,closure property of adjacent rock and hydrologic geology condition also(affect)gas content.The CBM enrichment is the result of effective multifactorial macthing.