页岩气水平井气层封固难点分析与技术对策

Difficulty analysis and technical countermeasures to the gas layer sealing ability for the shale gas horizontal well

武治强 周建良 靳勇 张红生

WU Zhiqiang ZHOU Jianliang JIN Yong ZHANG Hongsheng

中海油研究总院，北京　100027

Research Institute of China National Offshore Oilfield Corporation, Beijing 100027, China

页岩气开采常用完井方式是套管射孔+ 分段压裂技术，能否有效封固页岩产层，避免气体窜流泄漏和稳定气井产量，是页岩气水平井固井水泥环要经受考验的难题。从页岩地层特性、钻井施工条件以及后期增产作业等方面，分析了页岩气水平井气层封固面临的难点，提出了改善页岩气水平井水泥环封固能力的主要技术对策，应用了前置液固壁冲洗技术、可固化工作液技术、水泥石降脆增韧技术以及水泥环伤口自愈合技术。现场应用表明，该技术提高了水泥环的封固质量，延长了气井生产寿命。

The main completion method of shale gas reservoir is casing perforation plus separating layer fracture. The key challenges of horizontal well cement mantle are sealing shale gas production layer effectively, avoiding gas channeling leakage and stabilizing the gas production. From the aspects on the characteristics of shale layer, the condition of drilling construction as well as the operation in later production increasing, in accordance with analysis of the the facing difficulties in sealing horizontal well of shale gas reservoir, the paper proposes to take the main technical countermeasures for the improvement of sealing ability for the shale gas horizontal well, and apply the preposed liquid solid wall flushing technology, solidifiable operation liquid technology, cement stone dropping brittleness while strengthening toughness technology and cement ring self-healing technology. After application of the above technologies on the spot, it demonstrates that they have improved the sealing quality of the cement ring, and elongated the production life of the gas well.