Hydrogeologic feature of coalbed methane reservoir in the southern Qinshui Basin

Hydrogeologic condition is important for the high yield and enrichment of coalbed methane.Hydrogeologic unit in the southern Qinshui basin consists of lots of hydrogeologic subunits.Underground drainage divide results the gas-water yield performance complexity in coalbed methane wells.The northern interval of Jin-huo fracture fold belt on eastern boundary blocks the water in water-bearing beds in middle Ordovician formation horizontally,radial flow condition and water conductivity of underground water in southern interval is extremely poor.The water blocking property in middle interval of southern boundary is profitable for the preservation and enrichmentof coalbed methane in Jincheng.Western boundary is Anze,whose northern part is a water blockage boundary,southern part is water conducting fault.There are four important hydrogolgic boundaries in this area,in which Sitou fracture is a closed fracture whose water conductivity and gas conductivity is exceedingly poor.Underground water in terms of hydrostatic pressure encloses the coalbed methand in coalbed in Daning-Panzhuang-Fanzhuang district.It is profitable for the preservation and enrichment of coalbed methane that radial flow strength of underground water is probably weak in Zhengzhuang and nearby area of western Sitou fracture area.The enrichment condition of coalbed methane is good in Daning-Panzhuang-Fanzhuang district whose equipotential surface belongs to pothole stagnantpattern.