我国煤层气开发主要集中在煤层深度小于1 200 m的区域，埋深大于1 500 m的深部煤层气开发未取得实质性突破。针对深部软煤井壁稳定差、压裂改造难的问题，对沁水盆地深部软煤煤层气的开发开展了一系列技术攻关。研究结果表明：钻井过程中使用“氯化钾聚合物+井眼强化剂”钻井液体系，可有效控制煤层相对井径扩大率。使用16~18 m³/min超大排量、高液量、高砂量光套管压裂工艺，配合降阻剂来降低施工摩擦阻力，细砂、中砂、粗砂占总砂量体积比分别为15%、70%、15%，加砂量占总携砂液体积比自3%开始每次提高1%，可实现对深部软煤的充分改造，裂缝动态半长最大达到322.51 m，大幅提高了单井控制面积，排采产气效果良好。

The development of coalbed methane in China is mainly concentrated in areas with coal seam depth less than 1 200 m, and no substantial breakthrough has been made in deep coalbed methane with burial depth greater than 1 500 m.In view of the problems of poor stability of deep soft coal shaft and difficult fracturing reconstruction, a series of technical breakthroughs have been carried out on the development of deep soft coal bed methane in Qinshui Basin.The results show that in the drilling process, the drilling fluid system of "KCL polymer+borehole strengthening agent" can effectively control the relative borehole diameter expansion rate of coal seam.The parameter of 16 m³/min to 18 m³/min ultra-large displacement, high liquid volume and high sand volume smooth casing fracturing technology, which combined with resistance reducing agent could reduce construction friction.The proportion of fine sand, medium sand and coarse sand is 15%, 70% and 15%, respectively.The amount of sand added to the total sand carrying liquid volume ratio has been gradually increased since 3%, increase by 1% each time.This process can realize the full transformation of deep soft coal.The maximum dynamic half length of the fracture reaches 322.51 m, greatly increasing the control area of a single well.This makes the effect of gas drainage and production good.