川渝地区泥页岩层段解卡用酸液配方的应用进展

Advances in Acid Formulation Applications for Drillstring Unsticking in Sichuan-Chongqing Shale Reservoirs

摘要: 川渝龙马溪组泥页岩水平井因高硅质(SiO₂ 58%~83%)、强脆性、层理与微裂隙发育及长水平段钻进，导致黏附卡钻与坍塌掉块卡钻频发，事故占比15%~20%，时效损失严重。环空间隙狭小的旋转导向工具更易发生“秒杀式”卡死，常规机械震击与“寸提”法成功率低，失败后常致侧钻或井眼报废，且高温缓蚀失效易引发钻具酸蚀断裂等次生风险。现场表明，卡钻呈“压差黏附–剥落坍塌–固相填埋”多机制叠加，单一物理或常规盐酸处理难以高效解卡。酸液解卡技术通过溶蚀泥饼与掉块、降低摩阻恢复管柱活动性，已从常规盐酸体系演进为集“靶向溶蚀–井壁稳定–钻具防护”于一体的协同定制化技术。当前应用以土酸–有机弱酸复合体系与乳化/泡沫酸缓速酸并重，微乳酸等新型缓释体系在复杂工况下潜力突出，泡酸与物理解卡协同工艺日趋成熟。但仍面临高硅硬脆性页岩靶向溶蚀机理不明、120℃以上高温缓蚀长效性衰减、解卡效率与井壁稳定平衡调控困难、区块差异化定制化配方缺失等瓶颈。未来需发展分子设计型功能酸液、智能缓控释体系及“解卡–防塌–缓蚀”一体化集成技术，以突破现有难题，提升川渝复杂地层解卡效率与安全性。

Abstract: Horizontal drilling in Sichuan-Chongqing Longmaxi shale formations (SiO₂ 58%~83%) faces high risks of differential sticking and caving/sloughing accidents (15%~20% of drilling incidents) due to strong brittleness, developed bedding/microfractures, long laterals, and narrow-clearance rotary steerable systems (RSS), often causing severe time losses. Conventional methods (mechanical jarring, incremental lifting) exhibit low efficacy, while high-temperature corrosion inhibitor failures can lead to secondary risks like acid-induced drillstring fractures. Field observations reveal multi-mechanism sticking (differential pressure adhesion + spalling/collapse + solid embedment), rendering traditional HCl treatments ineffective. Recent advances in acid unsticking technology focus on synergistic systems integrating targeted dissolution, wellbore stabilization, and drillstring protection. Key approaches include mud acid-organic acid composites, retarded acids (emulsified/foam acids), and microemulsions for complex conditions, coupled with acid soaking + mechanical unsticking protocols. However, challenges persist: unclear dissolution mechanisms in high-silica shale, limited corrosion inhibitor longevity above 120˚C, balancing unsticking efficiency vs. wellbore integrity, and lack of block-specific formulations. Future research should prioritize molecular-designed acid fluids, intelligent controlled-release systems, and integrated unsticking-anticollapse-corrosion inhibition technologies to enhance efficiency and safety in these formations.