Guizhou Provincial Engineering and Technology Research Center of Coalbed Methane and Shale Gas Coal Mine Exploration of Guizhou Province

基于煤层气勘查开发示范工程,分析了黔西松河井田地温特征及其对煤层气开发的影响,探讨了龙潭煤系上煤组压裂工艺优选及下煤组压裂工艺优化方案。研究表明:受泥岩、煤层热导率低及煤系隔水性好、富水性弱的共同影响,龙潭煤系纵向地温梯度达3.57~4.65℃/hm,表现出明显的正地温梯度。基于不同温度下煤的等温吸附试验,45℃条件下下煤组各煤层煤层气可采系数与30℃相比提高了4.55%~11.67%;受此影响,下煤组压裂深度为620~900 m时,煤层气采收率较高。采用CO2泡沫压裂工艺适合井田下煤组超压、低渗、敏感性及滤失性强的储层特点,煤层埋深超过750 m即满足CO2泡沫压裂对储层温度的要求。同时,利用低温活性水压裂液注入可大幅降低上煤组储层温度,实现煤层气开发过程中的升温解吸、渗流。

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.

国家自然科学基金资助项目(51204162；41272154)；贵州省科技重大专项资助项目(黔科合重大专项字[2014]6002号)；