Abstract: According to the formation characteristics of shale gas wells in South Sichuan and the application of shale gas water-based drilling fluid in phase I, the shale gas water-based drilling fluid is optimized by introducing four core functional treatment agents, such as inhibitor, lubricant and plugging agent. The evaluation shows that the performance of shale gas Water-based drilling fluid is close to oil-based drilling fluid. In Zhao tong well YS-AB, the drilling operation in vertical section, deviation section and horizontal section was completed successfully. The shale gas water-based drilling fluid has good inhibition and sealing performance, and the borehole is stable; However, when the well trajectory changes greatly, the lubricity of drilling fluid is different from that of oil-based drilling fluid in engineering appearance. Based on the comprehensive analysis of shale gas water-based drilling fluid test application since 2015, the existing problems and misunderstandings of shale gas water-based drilling fluid are put forward. In order to reduce the drag and torque of drilling tools, it is suggested to enlarge the high temperature and high pressure filtration, reduce the plastic viscosity, increase the structural viscosity, strengthen the suspension stability, and ease the formation of “barite bed” and “cuttings bed” in the horizontal section.

Key words: shale gas water-based drilling fluid, high temperature and high pressure water loss, torque, drag, lubricity

摘要： 针对川南页岩气井地层特点和前期页岩气水基钻井液应用情况，通过引入插层抑制剂、双疏抑制剂、键合润滑剂、封堵剂 ４种核心功能性处理剂对页岩气水基钻井液进行优化，室内评价表明，页岩气水基钻井液性能与油基钻井液接近。在昭通 YS-AB井顺利完成该井直井段、造斜段和水平段钻井作业，该页岩气水基钻井液具有良好的抑制性、封堵性，岩屑返出成型，井壁稳定；但对于井眼轨迹变化较大井段，润滑性在工程表象上与油基相差较大。通过对 2015年以来页岩气水基钻井液试验应用情况的综合分析，提出了针对川渝地区页岩气水基钻井液存在问题与认识误区，建议适度放宽高温高压滤失量的要求，降低塑性黏度，适当提高结构黏度，强化悬浮稳定性，缓解水平段“岩屑床”与“重晶石床”的形成，以降低钻具摩阻、扭矩。

关键词: 页岩气水基钻井液, 高温高压滤失, 扭矩, 摩阻, 润滑性