应力效应下页岩动静态弹性各向异性特征  

Impacts of anisotropy on the dynamic and static elastic characteristics of shales under stress effects

作　　者：边会媛[1] 臧鑫 张迪 张程恩 聂晓敏 武银婷[5] BIAN Hui-Yuan;ZANG Xin;ZHANG Di;ZHANG Cheng-En;NIE Xiao-Min;WU Yin-Ting(College of Geology and Environment,Xi'an University of Science and Technology,Xi'an 710054,China;Exploration and Development Research Institute of PetroChina Qinghai Oilfield Company,Dunhuang 736202,China;Qinghai Provincial Key Laboratory of Plateau Saline-Lacustrine Basinal Oil&Gas Geology,Dunhuang 736202,China;Qinghai Branch of China Petroleum Logging Co.,Ltd.,Dunhuang 736202,China;College of Geology Engineering and Geomatics,Chang'an University,Shaanxi,Xi'an 710064,China)

机构地区：[1]西安科技大学地质与环境学院,陕西西安710054 [2]青海油田勘探开发研究院,甘肃敦煌736202 [3]青海省高原咸化湖盆油气地质重点实验室,甘肃敦煌736202 [4]中国石油集团测井有限公司青海分公司,甘肃敦煌736202 [5]长安大学地质工程与测绘学院,陕西西安710064

出　　处：《物探与化探》2024年第6期1664-1673,共10页Geophysical and Geochemical Exploration

基　　金：国家自然科学基金项目“基于声力效应的页岩动静态弹性特征响应机理研究”(42304143);陕西省自然科学基础研究计划项目“表面及层间多次波反演成像研究”(2022JM-139)。

摘　　要：静态弹性力学参数是页岩油开采及注水压裂工程的关键参数,应力效应下各向异性对页岩动静态弹性特征具有重要的影响,开展储层动静态弹性特征的主控因素与控制机理研究是页岩油气开采及注水压裂工程中一项亟须解决的关键科学问题。通过不同加压方式下页岩的三轴压缩力学与声学联测实验,研究各向异性对页岩纵、横波速度及宏观力学性质的影响,探究页岩动静态弹性特征的响应规律。结果表明:①随压力的增加,页岩动、静态杨氏模量增大,且增大速率由快到慢趋于稳定值;②层理角度一定时,动态杨氏模量大于静态杨氏模量,二者呈正相关,动、静态泊松比关系较差;③岩石动、静态刚度系数均随围压增大而增大,与纵波相关的动态刚度系数C_(11)、C_(33)比与横波相关的动态刚度系数C_(44)、C_(66)变化更明显;④页岩动、静态各向异性均随围压的增大而增大。研究结果可以揭示页岩动、静态弹性特征响应机理,并能够为页岩油气储层开采与水力压裂改造提供关键力学参数。The static elastic parameters are crucial for shale oil and gas production and fracturing through water injection.Under stress effects,anisotropy exerts significant impacts on the dynamic and static elastic characteristics of shales.Investigating the dominant factors and mechanisms controlling reservoirs'dynamic and static elastic characteristics is a burning key scientific problem in shale oil and gas production and fracturing through water injection.Based on triaxial compression tests combining mechanics and acoustics for shales under different pressurization methods,this study delved into the impacts of anisotropy on the compressional/shear wave(P-and S-wave)velocities and macromechanical properties of shales,and the response patterns of dynamic and static elastic characteristics of shales.The results are as follows:(1)With an increase in the pressure,the dynamic and static Young's moduli of shales increase at a gradually decelerating rate,finally tending to be stable;(2)At certain bedding angles,the dynamic and static Young's moduli are positively correlated,with the former higher than the latter,whereas the dynamic and static Poisson's ratios manifest a subtle correlation;(3)The dynamic and static stiffness coefficients of shales increase with the confining pressure.The P-wave-related dynamic stiffness coefficients C_(11) and C_(33) display more significant changes than the S-wave-related dynamic stiffness coefficients C_(44) and C_(66);(4)The dynamic and static anisotropies of shales also increase with the confining pressure.The results of this study reveal the response mechanisms of the dynamic and static elastic characteristics of shales while providing crucial mechanical parameters for the exploitation and hydraulic fracturing of shale oil and gas reservoirs,thus demonstrating significant scientific research value.

关 键 词：页岩油 各向异性 弹性性质 静态模量 地层压力 

分 类 号：P631.4[天文地球—地质矿产勘探]