含黏性流体孔隙介质分界面上反透射系数特征研究  

The characteristics of reflection and transmission coefficients at the interface of porous media saturated with a viscous fluid

作　　者：印兴耀[1] 周东勇 宗兆云[1] 陈本池[2] 卢莉 YIN XingYao;ZHOU DongYong;ZONG ZhaoYun;CHEN BenChi;LU Li(School of Geosciences,China University of Petroleum,Qingdao 266580,China;Technical Department,China Petrochemical Corporation,Beijing 100029,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,青岛266580 [2]中国石油化工集团公司科技部,北京100029

出　　处：《地球物理学报》2019年第6期2258-2266,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金(U1562215,41604101);国家科技重大专项课题(2016ZX05024-004,2017ZX05009-001,2017ZX05036-005,2017ZX05032-003)联合资助

摘　　要：地下岩石由岩石骨架和孔隙流体组成,通常流体含黏性.地震波在地下介质中传播时受岩石骨架和黏性流体的影响会呈现出复杂的变化.本文将流、固体位移和应力连续作为边界条件,推导出含黏性流体孔隙介质分界面上反透射系数方程;通过建立上层为饱油、下层为饱盐水的砂岩孔隙介质模型,开展反透射系数特征研究,分别分析不同频率、不同黏滞系数条件下,含黏性流体孔隙介质分界面上反透射系数随入射角的变化.研究表明,孔隙介质分界面上和等效介质分界面上的反透射系数分别随入射角的变化趋势基本一致,说明方程推导和数值计算的正确性;快纵波反透射系数受频率、流体黏性的影响较小,而快横波反透射系数在一定入射角范围内受频率、流体黏性的影响比较大;由于黏性孔隙流体的作用,慢纵波和慢横波的反透射系数受入射角、频率及流体黏性的影响都很大.The underground rock is composed of rock skeleton and pore fluids,and usually the fluids are viscous.When a seismic wave propagates in underground media,it will exhibit complex changes with the influence of rock skeleton and viscous fluids.In this paper,the continuities of displacement and strain in solid and fluid are taken as boundary conditions,and the equation of reflection and transmission coefficients at the interface of porous media with a viscous fluid are derived.Then,a geological model of sandstone porous media saturated with oil in the upper layer and brine in the bottom layer is established.On this basis,the characteristics of reflection and transmission coefficients are studied,and the variation of reflection and transmission coefficients with the change of the incident angles at the interface of porous media under different frequencies and viscosity coefficients are analyzed,respectively.The results show that the variation trends of reflection and transmission coefficients at the interface of porous media and the interface of their equivalent media with incident angles are basically the same,which indicates the correctness of the equation derivation and the numerical calculation.The reflection and transmission coefficients of the fast P-wave are less affected by the frequency and fluid viscosities,while that of the fast SV-wave are more affected by the frequency and fluid viscosities.As the existence of pore fluids and fluid viscosities,the reflection and transmission coefficients of the slow V-wave and slow SV-wave are greatly affected by incident angles,frequency and pore fluid viscosity.

关 键 词：黏性流体 孔隙介质 慢纵波 慢横波 反透射系数 

分 类 号：P631[天文地球—地质矿产勘探]