深层页岩储层现今地应力方向评价及其扰动力学机制——以川南永川区块五峰组——龙马溪组一段为例  

Evaluation of in−situ stress orientations and rotational mechanical mechanisms in deep shale reservoirs:A case study of the Longmaxi Formation's first member and Wufeng Formation in the Yongchuan shale gas field,southern Sichuan Basin

作　　者：李勇[1,2] 何建华[1] 曹峰 邓虎成 王园园[3] 李瑞雪 魏力民 李厂[1] LI Yong;HE Jianhua;CAO Feng;DENG Hucheng;WANG Yuanyuan;LI Ruixue;WEI Limin;LI Chang(College of Energy(College of Modern Shale Gas Industry),Chengdu University of Technology,Chengdu 610059,Sichuan,China;Exploration and Development Research Institute,PetroChina Daqing Oilfield Co.,Ltd.,Daqing 163712,Heilongjiang,China;Hainan Branch of China National Offshore Oil Corporation Ltd.,Haikou 570100,Hainan,China;Exploration and Development Research Institute Sinopec Southwest Oil&Gas Company,Chengdu 610041,Sichuan,China)

机构地区：[1]成都理工大学能源学院(页岩气现代产业学院),四川成都610059 [2]大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712 [3]中海石油(中国)有限公司海南分公司,海南海口570100 [4]中国石化西南油气分公司勘探开发研究院,四川成都610041

出　　处：《中国地质》2025年第1期78-94,共17页Geology in China

基　　金：国家自然科学基金青年项目(42402148);国家自然科学基金面上项目(42072182);四川省科技厅重点苗子项目(2022JDRC0103)联合资助。

摘　　要：【研究目的】川南深层页岩储层五峰组—龙马溪组现今地应力方向变化复杂,且局部构造对地应力方向的影响尚不清晰。【研究方法】以川南永川页岩气区块为例,基于古地磁和波速各向异性实验,结合测井、微地震监测以及数值模拟手段评价了应力方向的分布特征及构造变形影响下的偏转。【研究结果】当应力差异系数大于0.2,横波各向异性系数大于18%时,偶极横波测井解释的准确度显著提高;在高陡地层(>60°),需同时考虑两向差应力和高角度裂缝发育情况对现今地应力方向解释的影响。永川向斜区最大主应力方向分布为近EW向,背斜核部及断块区方向发生了较大方向的偏移(方向偏差最大为70°±5°)。永川地区五峰组—龙马溪组中和面应位于龙一段1~2小层,中和面上下地应力方向变化呈相反趋势,褶皱派生应力介于10~30 MPa,对区域应力的影响不可忽略;随着距断层距离的减少,泊松比(ν)呈增大趋势并使得最大主应力方向偏转。【结论】最大主应力方向有利于向斜区页岩气的保存,而背斜区的高角度天然裂缝则更易转变为有效裂缝。建议向斜区水平井部署方位为SN-NEE向;背斜区和夹持断块区以NE向为主且采用分层布井。[Objective]The present-day in-situ stress orientations within deep shale reservoirs of the Wufeng-Longmaxi Formation in the southern Sichuan Basin are intricate and have not been comprehensively evaluated.Moreover,the mechanisms through which local structures influence these stress orientations remain poorly understood.[Methods]The Yongchuan shale gas field was selected as the study area to systematically investigate the characteristics and controlling factors of in-situ stress orientations.This evaluation employed a multi-faceted approach that included paleomagnetic analysis,seismic wave velocity anisotropy measurements,specialized well logging techniques,microseismic monitoring,and numerical simulations.[Results]The accuracy of interpreting dipole shear wave logs significantly increased when the bidirectional stress difference coefficient exceeds 0.2 and the shear wave anisotropy index is above 18%.In the strata with steep dips(>60°),it is essential to consider the influence of bidirectional stress differentials and high-angle fracture development on the interpretation of in-situ stress orientations.The in-situ stress orientations in the northern and southern synclinal regions of Yongchuan area predominantly follow east-west trend.However,these orientations exhibit significant deviations in anticlinal and fault-influenced zones,with maximum angular discrepancies of approximately 70°±5°.Based on the observed reverse trends in stress orientations above and below a specific stratigraphic level,we hypothesize that the neutral surface is located within the 1-2 layers of the Longmaxi Formation in the Yongchuan area.Furthermore,the fold-induced stress,ranging from 10 MPa to 30 MPa,significantly impacts the principal stress field and cannot be overlooked.As the distance from the fault decreases,Poisson’s ratio(ν)increases,leading to a deflection in the in-situ stress orientations and exhibiting greater sensitivity to changes inν.[Conclusions]The orientation of maximum principal stress promotes the preservation

关 键 词：深层页岩储层 五峰组—龙马溪组 地应力方向 扰动机制 油气勘查工程 四川盆地 

分 类 号：TE311[石油与天然气工程—油气田开发工程] P618.13[天文地球—矿床学]