涪陵页岩气田井筒完整性实践与认识

Lessons Learned from Wellbore Integrity in Fuling Shale Gas Field

为了确保涪陵页岩气田页岩气水平井的安全开发,开展了页岩气水平井生产套管井筒完整性技术探索研究。基于管柱力学理论及套管设计+水泥浆固井+大型压裂的一体化理念,提出了页岩气水平井生产套管有效外载荷计算方法和生产套管柱优化设计方案,并对生产套管气密封螺纹进行特殊设计,完善了下套管现场操作保障措施和现场氦气密封检测工艺,形成了基于射孔与大型压裂的水平段弹韧性水泥浆固井配套技术,研发了针对页岩气生产套管螺纹密封失效的柔性化学堵漏技术。一期产建期间共完成了189口水平井的压裂投产,其中,仅有2口井井筒密封失效,采用柔性化学堵漏技术,使井筒密封失效的井得到了很好的治理。形成的生产套管井筒完整性系列技术基本满足了涪陵页岩气井安全正常生产的需求,为国内类似页岩气开发井井筒完整性工作提供了有益借鉴。

To ensure the safe development of shale gas horizontal wells in the Fuling shale gas field,a calculation method of effective external load of shale gas horizontal well production casing and a optimization design of the production casing string was proposed based on pipe string mechanics theory and the integration philosophy of casing design ＋ cementing ＋ large-scale fracturing. The air-tight seal casing thread was redesigned. The on-site operation safeguard measures of casing running and on-site casing sealing inspection technology using helium was impoved. The perforation and large-scale fracturing based horizontal well elastic cement slurry cementing technology has been developed. A flexible chemical plugging technology for shale gas production casing thread sealing failure has been developed. During the first phase of production and construction,a total of 189 horizontal wells were completed with fracturing treatment. Only two wells had failed borehole sealing,which were then remedied using the flexible chemical plugging technology. The wellbore integrity series technology of the production casing could basically meet the requirements for the safe production of the shale gas wells in Fuling,which provides a reference for wellbore integrity issues of similar shale gas development wells in China.