Geothermal characteristics and suitable CBM well fracturing technology in Songhe Mine Field

Based on the demonstratio project of coalbed methane( CBM) exploration and development ths paper analyzed the geothermal charactersics and itseffect on ClM development and discussed the coal goup frcturing optimzaton scheme of Longtan Formation in Songhe Mine Field,West cuizhou.The reseach hasshown that verical geothermal gradient was 3.57~4.65 ℃/ hm inLongtan Formatio by thecombined fiect of low thermal conductrvtyof mudstone and cealseam.ydrogeolocgical co ditions of well vater-es stng propery and l/ow water-richness,therefore the geothermal gradient s howed positive abnorma significantly in the LongtarFormaton. According to the experimentalresuts of sothermal adsorption under diferent temperatures.CBM recoverable co ficient increased by 4.55%~1.67% in awer cal group under the temperature co dion of 45 'C compared with 30 0C. Afcted by ths CBMl recovery ratio woud be higher when the bural depth of ower coal group was 620 ~ 900 m.cO2foanm fracturing fechnology was siablefor the reservoircharacteristics of high reservof pressure,lower original stong senstiy n fitrtio permeailit in ower coal group.,and reservoir temperature could met the CO2 foam fracturing requirement of higher than 4D "C, while the bural depth oflower coagroup was more than 750 mLow temperature active hydrauli fractrin fuid ine ction could signficanty reduce the resevor temperature of the upper coal group.andrforms CBM desorption,exploitation with coal reservoir temperature rising in the process of CBM development.