State Key Laboratory of Gas Disaster Detecting, Preventing and Emergency Controlling
China Coal Technology and Engineering Group Chongqing Research Institute

针对厚硬煤层抽采钻孔影响范围小,抽采纯量低,治理达标时间长等问题,采用顺煤层定向长钻孔分段压裂增渗技术对目标煤体进行物理改性和缝网改造。同时针对硬煤坐封过程中存在的封隔器破损及压裂液漏失难题,在掌握硬煤压裂破碎特性及封隔器力学参数特征的基础上,对其端部进行了主动承压“压环-内楔式”结构改进,优选了厚硬煤层裸眼坐封组合工具串,经实验室打压试验,密封效果良好,满足多次卸压膨胀要求。研发了厚硬煤层分段压裂成套装备及顺层定向长钻孔后退式分段压裂工艺,于山西亚美大宁矿3号煤层进行了2个定向长钻孔、8段压裂试验,累计钻孔深度975m,累计压入水量596m3。结果表明:试验区域钻孔瓦斯抽采浓度均在75%以上,采用地面微震监测、孔内瞬变电磁、区域渗水量综合判定压裂实际影响半径为22.5~32m,DY-1、DY-2钻孔瓦斯抽采纯量平均为1.36m3/min、1.22m3/min,压裂后单个钻孔抽采纯量最大提升49%,最小提升16%,平均提升约30%。

In response to the problems of small impact range, low extraction quality, and long treatment duration for drilling in thick and hard coal seams, the targeted coal body is physically modified and the fracture network is rebuilt using the directional long drilling segmented fracturing and permeability enhancement technology along the coal seam. In response to the problems of packer damage and fracturing fluid leakage during the hard coal setting process, based on the fracturing characteristics of hard coal and the mechanical parameter characteristics of the packer, an active pressure bearing “pressure ring to internal wedge” structure improvement is carried out at end part. The thick and hard coal seam open hole setting combination tool string is selected, and after laboratory pressure testing, the sealing effect is good, meeting the requirements of multiple pressure relief and expansion. We have developed a complete set of equipment for segmented fracturing in thick and hard coal seams, as well as a reverse segmented fracturing process for directional long boreholes. Two directional long boreholes and eight fracturing tests are conducted in No. 3 coal seam of Yamei Daning Mine, Shanxi, with a cumulative drilling depth of m and a cumulative water injection of m . The results showed that the gas extraction concentration in the experimental area is all above 75%. The actual impact radius of fracturing is determined by ground microseismic monitoring, transient electromagnetic in the hole, and comprehensive determination of regional seepage volume, which is 22. 5~32 m. The average pure gas extraction volume in DY-1 and DY-2 boreholes are 1. 36 m / min and 1. 22 m / min, respectively. After fracturing, the maximum and minimum pure gas extraction volume in a single borehole are increased by 49% and 16%, with an average increase of about 30%.

天地科技股份有限公司科技创新创业资金专项项目(2022-2-TD-ZD008)

秦逢缘,武文宾,李良伟,等.厚硬煤层定向长钻孔分段压裂增渗技术及应用[J].煤炭工程,2025,57(1):98-105.