摘要
动、静态弹性参数转换关系对陆相页岩储层压裂改造、钻井方案设计、地应力预测等地质工程问题有重要意义.但页岩的本征各向异性及动、静态弹性参数的强压力依赖性对建立各向异性背景下的动、静弹性参数转换模型提出了新的挑战.本次实验研究基于10组四川盆地侏罗系陆相页岩样品的各向异性动、静态弹性参数联合测试,建立了模拟原位有效应力条件下各向异性动、静态弹性参数建模工作流程.多级偏应力循环实验结果表明:无论是在垂直还是平行层理方向,动态杨氏模量和泊松比均系统性地大于对应的静态杨氏模量和泊松比,并且动、静态弹性参数都表现出明显的压力依赖性.根据围压为20 MPa时的实测数据,直接建立了垂直层理方向模拟原位应力的动、静杨氏模量和泊松比转换关系.在此基础上,假定动态、静态杨氏模量各向异性的关系不依赖于所施加应力大小,建立了动、静态杨氏模量各向异性强度之间的线性关系,进而间接获得了模拟原位应力条件下的平行层理方向静态杨氏模量.各向异性背景下的动、静态弹性参数转换模型可将测井或地震数据转换为原位有效应力条件下的静态弹性参数,并可为各向异性背景下页岩储层地应力预测提供指导.
Dynamic-static elasticity correlations of lacustrine shales are of great significance in many geoengineering applications,like hydraulic fracturing,drilling design,and in situ stress prediction.However,the shale intrinsic anisotropy together with the strong pressure dependence of both dynamic and static parameters make the anisotropic dynamic-static correlations challenging.We provide a workflow for establishing anisotropic dynamic-static elasticity correlations with consideration of the in situ stress for 10 pairs of Jurassic shales.The multi-stage deviatoric stress cycling tests suggest that dynamic Young′s moduli and Poisson′s ratios are systematically greater than their static equivalents,no matter in the bedding-normal or bedding-parallel direction.Both dynamic and static parameters are strongly dependent on the applied confining pressure.The bedding-normal dynamic-static Young′s modulus and Poisson′s ratio correlations are directly established based on the measured data at the confining pressure of 20 MPa.Then,we establish the linear relationship between dynamic and static Young′s modulus anisotropy assuming that the dynamic and static anisotropy relationship is not dependent on the applied stress.Subsequently,the bedding-parallel static Young′s modulus is predicted based on the above two relations.The established dynamic-static elasticity correlations could be used to transfer well log or seismic data to static Young′s modulus and Poisson′s ratio,which could offer guidance for anisotropic in situ stress prediction.
作者
刘卫华
王洋
陈祖庆
陈超
沈珲
张方南
仉涛
LIU WeiHua;WANG Yang;CHEN ZuQing;CHEN Chao;SHEN Hui;ZHANG FangNan;ZHANG Tao(SINOPEC Geophysical Research Institute Co.,Ltd.,Nanjing 211103,China;SINOPEC Key Laboratory of Geophysics,Nanjing 211103,China;SINOPEC Exploration Company,Chengdu 610041,China)
出处
《地球物理学报》
北大核心
2025年第1期213-228,共16页
Chinese Journal of Geophysics
基金
国家重点研发计划(2019YFC0604902)资助。
关键词
各向异性
杨氏模量
泊松比
动静态转换
多级偏应力循环
Anisotropy
Young′s modulus
Poisson′s ratio
Dynamic-static correlation
Multi-stage deviatoric stress cycling
