相国寺储气库低压易漏失井固井技术

相国寺构造地质情况复杂,上部须家河组—嘉陵江组地层极易发生恶性井漏,下部石炭系等主力气藏的地层压力系数极低,下套管及固井施工中也极易发生漏失,严重影响环空水泥环的密封完整性。通过开展地层承压试验、钻井液性能调整技术、前置低密度先导浆固井技术、正注反打固井工艺的研究,以及优选具有防漏、堵漏效果的水泥浆体系,基本形成了一套适用于相国寺储气库注采井固井的防漏、堵漏技术,成功解决了低压易漏失的固井难题,实现了环空有效完全充填。

Cementing technology of low pressure and easy leaking well in Xiangguosi underground gas storage

The geological structure is very complex in Xiangguosi underground gas storage. Vicious leakages happen readily in Xujiahe-Jialingjiang Formation layem and the pressure coefficient is usually very low in major Carboniferous gas reservoirs of lower part. Leakage usually happens during casing and cementing operation, which can seriously affect the sealing integrity of cement sheath. Cementing technologies of leak resistance which are fit for demand of easy leaking well in Xiangguasi underground gas storage are developed through launching layer pressurization test, regulating technology of drilling fluid properties before cementing, prepositive low density leading technology, positive and inveme injection cementing technology, and selecting lost circulation slurry system with leaking resistance and stoppging effect. Utilizing the above mentioned techniques, the cementing problem of low pressure and easy leaking well is solved in this structure and the effective annular f＇dling by slurry is achieved.