页岩气藏裂缝区地层孔隙压力准确求取方法

A Method for Accurate Calculation of Pore Pressure in Fractured Formations of Shale Gas Reservoirs

王怡

WANG Yi

页岩油气富集机理与有效开发国家重点实验室，北京 100101 中国石化石油工程技术研究院，北京 100101

State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing, 100101, China Sinopec Research Institute of Petroleum Engineering, Beijing, 100101, China

在钻遇页岩气藏裂缝区地层时，正钻井的地层压力与原始地层压力有较大差异，压裂后地层压力比压裂前地层压力有显著升高，利用传统孔隙压力预测方法求取的页岩气藏裂缝区地层孔隙压力不够准确。针对该问题，分析了不同工况下页岩气藏裂缝区地层孔隙压力动态变化的原因以及页岩储层的压裂增压机理，并提出了一种钻遇天然裂缝区及压裂作业区时求取动态变化的页岩气储层孔隙压力的方法。应用实例表明，该方法原理简单、机理明确，与现场测试结果吻合程度高，为一种准确求取页岩气藏裂缝区动态变化孔隙压力的有效方法，具有较高的实用价值。

When drilling through the fractured formations of a shale gas reservoir, the formation pressure will exhibits a significant difference from normal pressure as well as after fracturing. It is hard to obtain accurate formation pore pressure in fractured formations of shale gas reservoirs by using traditional pore pressure prediction methods. To tackle this problem, we analyze the causes of dynamic changes in formation pressure in fractured formations under different operating conditions. We also analyze the large increase of formation pressure after shale gas reservoirs stimulation. Based on those analyses, we propose a method of calculating pore pressure change in both naturally fractured and stimulated shale gas reservoirs. Applying the method shows it has asimple principle and clear mechanism, and gives results which highly agree with those from field tests. As an effective method for accurately calculating dynamic pore pressure in fractured formations of shale gas reservoirs, this method offers high practical value.

国家科技重大专项课题“涪陵页岩气水平井钻完井技术研究”（编号：2016ZX05060-012）、国家自然科学基金企业创新发展联合基金课题“高温高压油气安全高效钻完井工程基础理论与方法”（编号：U19B6003-05）、中国石化“十条龙”科技攻关项目课题“涪陵页岩气田焦石坝区块开发调整井钻完井关键技术”（编号：P18052-3）联合资助

https://doi.org/10.11911/syztjs.2020056