渗透率各向异性条件下裂缝介质地震频散、衰减及各向异性分析  

Analysis of seismic wave dispersion,attenuation and anisotropy of fractured media under anisotropic permeability

作　　者：姜晓敏 陈学华[1,2] 吴昊杰 罗鑫[1] 刘俊杰 JIANG Xiaomin;CHEN Xuehua;WU Haojie;LUO Xin;LIU Junjie(State Key Laboratory of Oil&Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Key Lab of Earth Exploration&Information Techniques of Ministry of Education,Chengdu University of Technology,Chengdu,Sichuan 610059,China)

机构地区：[1]成都理工大学油气藏地质及开发工程国家重点实验室,四川成都610059 [2]成都理工大学地球勘探与信息技术教育部重点实验室,四川成都610059

出　　处：《石油地球物理勘探》2023年第4期902-912,共11页Oil Geophysical Prospecting

基　　金：国家自然科学基金项目“致密储层裂缝系统诱发地震异常的机理及其与储层产能的关系”(41874143);四川省自然科学基金重点项目“深层储层裂缝渗流结构的地震岩石物理响应机理与检测方法”(2023NSFSC0019)联合资助。

摘　　要：渗透率各向异性与地震各向异性是含流体裂缝孔隙岩石的关键特性,文中利用裂缝参数(倾角、方位角、半径等)表征裂缝介质的渗透率并分析渗透率各向异性变化规律,基于Chapman多组裂缝等效介质模型研究了渗透率各向异性条件下正交介质的地震各向异性及地震波频散、衰减特征。数值模拟结果表明:①渗透率各向异性与裂缝参数有关,裂缝方位角的变化对渗透率各向异性的影响具有对称性;裂缝半径和倾角的变化影响渗透率各向异性的强弱,其中裂缝半径的影响尤为显著。②渗透率各向异性情况下,地震波的频散、衰减出现两个不同的弛豫时间,随着饱含流体裂缝介质中含气量的增加,特征频率呈现先减后增的趋势。③渗透率差异引起的两个不同的特征频率与地震各向异性系数极值对应的频率具有相关性,表明渗透率各向异性会引起地震频散、衰减的各向异性。数值分析结果可为裂缝储层渗透率预测及流体识别提供有力的理论依据。Permeability anisotropy and seismic anisotropy are the key characteristics of fluid‑bearing fracture‑pore rock.In this paper,fracture parameters(dip angle,azimuth angle,radius,etc.)are used to characterize the permeability of fractured media and analyze the anisotropy variation of permeability.The seismic anisotropy and dispersion‑attenuation characteristics of seismic waves of orthogonal media under permeability anisotropy are studied based on Chapman’s multi‑group fracture equivalent medium model.The numerical simulation results show that:①The permeability anisotropy changes with fracture parameters and is symmetrically influenced by fracture azimuth angle;the variation of fracture radius and dip angle affects the permeability anisotropy,especially the fracture radius.②In the case of permeability anisotropy,there are two different relaxation time for the dispersion and attenuation of seismic waves,and the characteristic frequency decreases first and then increases with the increase in gas content in the fluid‑bearing fractured medium.③The two different characteristic frequencies produced by different permeability are related to the frequency corresponding to the extreme value of the seismic anisotropy coefficient.This indicates that permeability anisotropy can cause anisotropy of seismic dispersion and attenuation.The numerical analysis results in this paper can provide a powerful theoretical basis for the prediction of reservoir permeability and fluid identification in fractured reservoirs.

关 键 词：裂缝参数 渗透率各向异性 地震各向异性 频散 衰减 

分 类 号：P631[天文地球—地质矿产勘探]