基于声波测试法对鹰滩页岩各向异性分析  

Anisotropic Properties of the Eagle Ford Shale by Ultrasonic Velocity Measurements

作　　者：李卉[1] 魏臣兴 俞宏伟[3] 赵昕[3] 来超 李奔[1] 李岩 LI Hui;WEI Chenxing;YU Hongwei;ZHAO Xin;LAI Chao;LI Ben;LI Yan(China University of Petroleum,Beijing 102249;Guangdong University of Petrochemical Technology,Maoming,Guangdong 525000;CNPC Research Institute of Petroleum Exploration and Development,Beijing 100083;CNPC Changqing Oilfield Company,Xi’an,Shaanxi 017300;Institute of Mineral Resources Research,China MetallurgicalGeology Bureau,Beijing 101300)

机构地区：[1]中国石油大学北京,北京102249 [2]广东石油化工学院,广东茂名525000 [3]中国石油勘探开发研究院,北京100083 [4]中国石油长庆油田分公司第四采气厂,陕西西安017300 [5]中国冶金地质总局矿产资源研究院,北京101300

出　　处：《地质与勘探》2022年第6期1291-1299,共9页Geology and Exploration

基　　金：中石油科技创新基金(编号:2019D-5007-0201);中国石油天然气集团公司重大战略项目(编号:ZLZX2020-01-04);陕西省自然科学基础研究计划(编号:2020JM-534)联合资助

摘　　要：页岩储层通常呈薄层状结构,一般认为其岩石力学参数具有横向各向同性,而其各向异性受围压(CP)、含水率和总有机质含量(TOC)等多种因素的影响。本文对不同围压下的鹰滩(Eagle Ford)页岩进行超声波波速测试实验,研究围压对鹰滩页岩波速及岩石力学各向异性的影响。实验结果表明,鹰滩页岩属于弱各向异性多孔介质,并具有横向各向同性、垂向各向异性的性质。纵波(P波)和横波(S波)波速随围压的增大而增大,特别是在低围压范围内增幅显著,同时围压增大会降低纵波和横波的各向异性,纵波各向异性比横波各向异性对围压更敏感。对鹰滩页岩的各向异性分析为页岩储层压裂过程中裂缝的起裂和延伸规律研究提供了必要的力学参数。Organic-rich gas shales are often composed of thin laminated structures which may be considered as transversely isotropic material.The anisotropic properties of shales are affected by many factors,including confining pressure,water content,and total organic content(TOC).This work performed ultrasonic velocity measurements at various confining pressures to investigate the effects of confining pressure on anisotropic properties of the Eagle Ford shale.Results show that the Eagle Ford shale is weak elastic anisotropic porous medium which has transversely isotropic and vertical anisotropic properties.Both compressional(P)and shear(S)wave velocities increase as confining pressure increase,especially at low confining pressure range.Increasing confining pressure decreases both P-and S-wave anisotropy,and P-wave anisotropy is more sensitive to confining pressure than S-wave anisotropy.The analysis of anisotropic properties of Eagle Ford shale could provide useful mechanical parameters for understanding the initiation and distribution of fractures during hydraulic fracturing.

关 键 词：页岩 声波测试 围压 各向异性 横向各向同性 

分 类 号：TU522.12[建筑科学—建筑技术科学]