涪陵页岩气井“套中固套”机械封隔重复压裂技术

“Casing in Casing” Mechanical Isolation Refracturing Technology in Fuling Shale Gas Wells

刘尧文 明月 张旭东 卞晓冰 张驰 王海涛

LIU Yaowen MING Yue ZHANG Xudong BIAN Xiaobing ZHANG Chi WANG Haitao

中石化重庆涪陵页岩气勘探开发有限公司，重庆 408100 中国石化石油工程技术研究院，北京 102206

Sinopec Chongqing Fuling Shale Gas Exploration and Development Company, Chongqing, 408100, China Sinopec Research Institute of Petroleum Engineering, Beijing, 102206, China

针对涪陵页岩气田采用暂堵转向重复压裂工艺时施工难度大、增产效果不理想的问题，在调研国外页岩气井重复压裂工艺的基础上，对比分析了暂堵转向重复压裂与机械封隔重复压裂技术的原理与特点，明确了机械封隔可完全封堵初次压裂射孔炮眼，精准控制重复压裂水力裂缝起裂，形成了“套中固套”机械封隔重复压裂技术。在涪陵页岩气田JYAHF井进行了“套中固套”机械封隔重复压裂技术试验，在内径为115.0 mm的井筒中下入ϕ88.9 mm套管固井，建立全新封闭井筒，并针对不同剩余储量分布采用不同的重复压裂工艺。原井筒改造程度较高的井段，以挖潜老缝间剩余资源为目标；初次改造效果差的井段，需要恢复老缝导流能力。JYAHF井试验该技术后，可采储量增加0.36×108 m3，采收率提高4.8%。研究结果表明，“套中固套”机械封隔重复压裂技术增产效果明显，可为国内页岩气田长期高效开发提供技术支撑。

The application of temporary plugging and diverting refracturing in Fuling Shale Gas Field brought on technical difficulties accompanied by poor production increase. To solve this problem, this paper analyzed principles and characteristics of technologies used in shale gas wells abroad. They included temporary plugging and diverting refracturing, and mechanical isolation refracturing. What was found was that that mechanical isolation could completely block the perforations and precisely control fracture initiation of hydraulic refracturing. From that, the “casing in casing” mechanical isolation refracturing technology took shape. In Fuling Shale Gas Field, this technology was tested with a casing (outer diameter of 88.9 mm) inserted into the other one (inner diameter of 115.0 mm) where in a new and closed well casing was formed. In addition, refracturing technologies targeted for different residual oil distribution in the reservoir were developed through studies. In the original well casing, attention should be paid to exploring the residual oil among fractures in the stimulated well section. At the same time,emphasis should target the poorly stimulated sections, to see how to recover the flow conductivity of the fractures. After implementing that technology in Well JYAHF, the recoverable reserve for a single well increased by 0.36×108 m3, and the recovery efficiency increased by 4.8%. The study shows that the “casing in casing” mechanical isolation refracturing technology can significantly improve the result of stimulation and provide technical support for long-term and efficient shale gas field development in China.

国家自然科学基金企业创新发展联合基金项目“海相深层油气富集机理与关键工程技术基础研究”（编号：U19B6003）资助

https://doi.org/10.11911/syztjs.2022010