适合页岩气钻井堵漏的环保型堵漏剂AT-SPS性能评价与应用工艺

Performance evaluation and application process of environment-friendly plugging agent AT-SPS in shale gas drilling

针对页岩气表层因地层风化剥蚀和裂缝发育等因素导致的恶性井漏问题,利用液体膨胀原理,采用环保型堵漏剂AT-SPS进行封堵。室内性能评价结果表明:该堵漏剂遇水即快速发生反应,体积膨胀数倍并形成不溶于水的固结体,达到填充漏失通道封堵的目的。根据该堵漏剂的膨胀特性,结合长宁页岩气表层恶性漏失多为溶洞性漏失的特点,制定了应用工艺。采用专用输送工具将堵漏剂注入漏层,堵漏剂遇地层水后快速发生反应,形成坚硬的固化体以封住漏层和水层。该堵漏剂在长宁某页岩气区块进行了4井次的应用,大幅降低了漏失,稳定了井壁,保证顺利钻进至目的井深。介绍了环保型遇水膨胀堵漏剂的基本原理、实验评价和应用工艺,为现场应用奠定了基础。

Lost circulation in the surface layer of shale gas is a significant problem caused by stratum weathering and erosion,crack development,and other factors.To address this issue,an environment-friendly plugging agent AT-SPS was used for plugging according to the principle of expansion of liquids.The results of laboratory performance evaluation showed that the plugging agent immediately reacted with water,expanded by several times,and produced a water-fast induration,which filled and plugged the leaking channel.Based on the expansion characteristics of the plugging agent and the characteristics of the karst cave leakage in Changning shale gas,the application process has been formulated.The plugging agent is injected into the leaking layer using a special transport instrument.After coming into contact with water,the plugging agent immediately engaged in rapid reaction,and produced a solid induration,which plugged the leaking layer and the water layer.The plugging agent has been applied in a shale gas well in Changning for 4 wells,which greatly reduced the leakage,stabilized the well wall and ensured that shaft drilling could proceed to the intended depth.This study introduced the basic principles,experimental evaluation,and application process of the environment-friendly water-swelling plugging agent,laying a foundation for further field applications.