深层页岩储层“工程甜点”评价与优选——以川南永川、丁山地区为例

Evaluation and optimization of "engineering sweet spot" in deep shale reservoir: case study on Yongchuan and Dingshan areas in southern Sichuan

葛勋 郭彤楼 黎茂稳 赵培荣 邓虎成 李王鹏 钟城

GE Xun GUO Tonglou LI Maowen ZHAO Peirong DENG Hucheng LI Wangpeng ZHONG Cheng

中国石化 石油勘探开发研究院, 北京 102206 中国石化 西南油气分公司, 成都 610041 中国石化 油田勘探开发事业部, 北京 100728 成都理工大学 能源学院, 成都 610059 南京大学 地球科学与工程学院, 南京 210033

Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 102206, China Southwest Oil and Gas Branch Company, SINOPEC, Chengdu, Sichuan 610041, China Oilfield Exploration & Production Department, SINOPEC, Beijing 100728, China College of Energy, Chengdu University of Technology, Chengdu, Sichuan 610059, China School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu 210033, China

四川盆地深层地质条件复杂，页岩储层埋藏深度大，气井产能普遍偏低，压裂施工面临极大挑战。为寻找深层页岩气“工程甜点”，以永川、丁山地区为例，利用钻井、岩心、成像测井、地震等资料，基于实测岩石力学参数、天然裂缝发育程度、天然裂缝有效性、水平应力差以及水平井轨迹与最小水平主应力夹角，对永川、丁山地区深层页岩储层水力压裂效果影响因素进行深入探讨。研究结果表明，川南永川、丁山地区龙一段31小层脆性最好，为压裂首选目的层；离断层越近，泵压和施工压力越升高，改造体积下降；水力裂缝与天然裂缝夹角在55°左右时，可以保证裂缝具有较好的延伸与转向能力；在高硅质页岩段和断层带内，最小水平主应力越小，水力裂缝越易扩散；水平井轨迹与最大水平主应力方位夹角越大，压裂效果越好。最终建立了永川、丁山复杂构造区海相页岩气“工程甜点”的评价指标体系，优选出永川、丁山Ⅰ类地质工程“甜点”区。

In the Sichuan Basin, geologic conditions are complex in deep layers. Burial depth of shale reservoirs is high. Gas well productivity is widespread low, and hydraulic fracturing confronts with extremely large challenges. In order to search for "engineering sweet spots" of deep shale gas layers, Yongchuan and Dingshan areas were taken as the examples. In-depth discussion was conducted on affecting factors of hydraulic fracturing results in deep shale reservoirs by drilling, core, imaging logging and seismic data, based on measured rock mechanical parameters, development degree of natural fractures, natural fracture effectiveness, horizontal stress difference and included angle between horizontal well track and the minimum main horizontal stress. Study results demonstrated that No.31 sublayer of the first member of Longmaxi Formation in Yongchuan and Dingshan areas, southern Sichuan had the best brittleness as the first-choice target horizon for hydraulic fracturing. Shorter distance from the faults, higher pump pressure and operational pressure, and smaller reconstructed volume. Good extension and turning capacity of the fractures could beguaranteed when included angle between hydraulic and natural fractures was roughly 55°. In silicon-rich shale and faulting zones, lower minimum main horizontal stress, easier-diffused hydraulic fractures. Higher included angle between horizontal well track and maximum main horizontal stress azimuth, better fracturing results. Finally, evaluation index system of "engineering sweet spots" for marine shale gas in complex structural areas of Yongchuan and Dingshan was constructed. Class Ⅰ geologic and engineering "sweet spots" were optimized in Yongchuan and Dingshan areas.

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” U19B6003

https://doi.org/10.11781/sysydz202302210