贵州铜仁地区页岩气钻井施工难点及对策

Difficulties of Shale Gas Well Drilling Construction in Tongren of Guizhou and the Countermeasures

在贵州铜仁地区施工页岩气地质调查井,因地层构造较复杂,上部灰岩地层岩溶、溶隙发育,在钻井过程中存在井壁易垮塌、掉块卡钻,井内漏失严重,供水困难等难点。秀页2井设计井深1900 m,由于钻井液漏失严重,水泥浆封孔堵漏过程中发生掉块卡钻事故,处理无果导致钻井中途报废。移机重新开始,采用较大口径开孔、多级绳索取心钻进、分段水泥堵漏、多层套管护壁的方案,顺利终孔。本文重点从水泥封孔堵漏方面总结该孔的钻井技术经验,为该区域页岩气井施工提供参考。

In shale gas geological survey well construction in Tongren of Guizhou, because of the complex strata structure with development of karst and dissolution in the upper limestone strata, the wall is prone to collapse with block falling and drill pipe sticking, serious leakage and difficult water supply. The depth of Xiuye2 well was designed for 1900m, but this well was halfway abandoned due to the serious lost circulation, block failing and drill pipe sticking in the process of cement slurry sealing and plugging. After drill shifting, the scheme of hole opening with large diameter, multi-stage wire-line core drilling, sublevel cementing plugging and wall protection by multi-layer casing was adopted, the hole construction was com- pleted smoothly. This paper summarizes the drilling experience mainly in cement sealing and plugging to provide reference to shale gas well construction in this area.