部分饱和裂隙储层中相对渗透率对黏弹性波频变各向异性的影响  

Effects of relative permeability on frequency-dependent anisotropy of viscoelastic waves in partially saturated fractured reservoirs

作　　者：张青 廖建平[1,2,3] 徐云贵[4] 周林 谢敬涛 ZHANG Qing;LIAO JianPing;XU YunGui;ZHOU Lin;XIE JingTao(School of Earth Science and Spatial Information Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;Sinopec Key Laboratory of Geophysics,SINOPEC Geophysical Research Institute Co.,Ltd.,Nanjing 211103,China;Chongqing Institute of Unconventional Oil and Gas,Chongqing University of Science and Technology,Chongqing 401331,China;School of Earth Science and Technology,Southwest Petroleum University,Chengdu 610500,China)

机构地区：[1]湖南科技大学地球科学与空间信息工程学院,湘潭411201 [2]中国石化地球物理重点实验室,中石化石油物探技术研究院有限公司,南京211103 [3]重庆科技学院非常规油气开发研究院,重庆401331 [4]西南石油大学地球科学与技术学院,成都610500

出　　处：《地球物理学进展》2023年第3期1257-1271,共15页Progress in Geophysics

基　　金：国家自然科学基金项目(42074167,41874156,41904116);湖南省自然科学基金(2023JJ30234);湖南省研究生科研创新项目(CX20221087);中石化地球物理重点实验室开放基金(33550006-22-FW0399-0027,33550006-20-ZC0699-00-12-ZR01)联合资助。

摘　　要：相对渗透率是研究多相流体在多孔介质流动的一个有效工具,但现有研究主要考虑孔隙介质为单相流体填充,且介质的均匀完全弹性理论受到挑战,没有考虑到油气藏为多相流体饱和,所建立的岩石物理模型存在局限性.本文着重于研究地震波在黏弹性介质和两相流体部分饱和时的情况,基于Chapman频变各向异性理论,建立了双相不混溶流体的黏弹性频变各向异性介质中,同时包含喷射流力学机制和斑块效应的统一地震波传播的新模型,并考虑了不同气水两相的相对渗透率模型对黏弹性频变各向异性的影响.首先,研究无裂缝介质的情况下,不同气水两相的相对渗透率对剪切模量、横波速度、横波衰减随含水饱和度变化的影响.然后,讨论了存在裂缝介质的情况下,相对渗透率对横波分裂、准纵波速度,及准纵波速度随地震波传播方向与裂缝法线之间角度,随含水饱和度变化的影响.对比分析无相对渗透率和存在相对渗透率的结果,发现考虑相对渗透率效应更符合黏弹性介质下的变化规律.数值试验的结果证实了本文的方法正确、有效,同时进一步说明了相对渗透率效应可能导致剪切特性和纵波速度随含水饱和度非单调变化,这可能使得地震资料中反演流体含量变得复杂.Relative permeability is an effective tool to study the flow of multiphase fluid in porous medium,but the existing researches mainly consider that the porous medium is filled with single-phase fluid,and the uniform and complete elastic theory of the medium is challenged,without considering oil and gas reservoirs as saturated with multiphase fluids,and the established petrophysical model has limitations.This paper focuses on the study of seismic waves in viscoelastic medium and two-phase fluids partially saturated.On the basis of the frequency-dependent anisotropy theory proposed by Chapman,a new model of unified seismic wave propagation in viscoelastic frequency-dependent anisotropic medium with two-phase immiscible fluids is developed,which contains both mechanics mechanisms of squirt flow and patchy effects.The effects of different relative permeability models of gas and water phases on the viscoelastic frequency-dependent anisotropy are also considered.Firstly,the effects of different gas-water two-phase relative permeability models on the variation of shear modulus,s-wave velocity and s-wave attenuation with water saturation are investigated in the case of non-fractured medium.Then,the effect of the relative permeability model on the variation of s-wave splitting,quasi p-wave velocity and quasi p-wave velocity with the angle between the wave propagation direction and the fracture normal with water saturation is discussed in the presence of fractured medium.Comparing the results without and with the presence of relative permeability,it is found that considering the effect of relative permeability is more in line with the change law in viscoelastic medium.The results of the numerical experiments confirm the correctness and validity of the method proposed in this paper,and further illustrate that the relative permeability effect may lead to non-monotonic variation of shear properties and p-wave velocity with water content saturation,which may complicate the inversion of fluid content in seismic data.

关 键 词：相对渗透率效应 部分饱和 黏弹性介质理论 频变各向异性 气水两相流体 

分 类 号：P631[天文地球—地质矿产勘探]