川南区块页岩气井压稳防漏固井技术研究

Research on pressure stabilization and anti⁃leakage cementingtechnology of shale gas in Southern Sichuan Block

川南区块深层页岩气井技术套管井深在2600~2900 m,通过前期11井次的技术套管固井施工,发现该区块技术套管固井主要难题为发育多套气层,浅层气活跃,同时茅口组易漏失,固井过程中压稳与防漏矛盾突出。本文系统分析了川南区块页岩气技术套管固井面临的主要难题,通过开展易漏地层堵漏后承压能力研究,水泥浆及浆柱结构设计,注替排量设计,压稳辅助技术研究,形成了一套适合川南区块页岩气技术套管多套气层固井压稳防漏的工艺技术,现场应用效果显著。

The technical casing depth of shale gas wells in Southern Sichuan Block is 2600~2900 m.Through the previous 11 times of technical casing cementing construction,it is found that the main problems of technical casing cementing in this block are the development of multiple gas layers with active shallow gas,and the Maokou Formation is easy to leak.In the process of cementing,the contradiction between pressure stabilization and anti‑leakage is prominent.This paper systematically analyzes the main problems encountered in the process of technical casing cementing of shale gas in Southern Sichuan Block.Through the research on the pressure bearing capacity after plugging in easy‑to‑leak formations and the design of cement slurry,slurry column structure,displacement,and the auxiliary technology for pressure stabilization,a set of process technology suitable for the cementing of shale gas technical casing cementing in Southern Sichuan Block is formed,and the effect of field application is remarkable.