Flexibility energy of coal-bed gas reservoir in Zhina coalfield and their control function on the favorable areas

Abstract：Based on a large number of coal field geological exploration data and the results which were obtained in coal bed methane exploration recently,discussed the distribution rule and characteristic of the flexibility energy in the Zhina coalfield＇s main coal seam both laterally and vertically.Through analyzing the three parameters of coal seam fissure system index（ξ1）,coal seam pressure system index（ξ2）and coal seam fracture opening-closing coefficient（Δ）,clarified the stratum energy of coal-bed gas reservoir and their control function on the favorable areas.The study indicate that on the surface,the distribution pattern of the flexibility energy in the Zhina coalfield＇s main coal seam is showed that high in the west and lower in the east,high in the south and lower in the north,significantly high in the southwest;on the vertical direction,the distribution rules is that as the low of coal bed seam,the energy gradually increases.Favorable Δ,favorable ξ1 and favorable ξ2 are less than 0.1,more than 2 and more than 0.9,and mainly distributes in Huale-Baixing-Zhangjiawan-Houzhai-Zhuzang-Pingshang-Xinhua,is in the southwest coalfield.It is explained that this area is the favorable area of the coal bed gas＇s enrichment and mining in Zhina coalfield has a migration and stress favorable system.