孔弹性介质快慢纵波及横波真振幅矢量波场分离方法  

A true-amplitude vector wavefield decomposion method for fast-P,slow-P and S-waves in poroelastic medium

作　　者：杨继东 田祎伟 张鑫 黄建平[1] 郭威 杨永红[3] YANG Jidong;TIAN Yiwei;ZHANG Xin;HUANG Jianping;GUO Wei;YANG Yonghong(School of Geosciences in China University of Petroleum(East China),Qingdao 266580,China;Shandong Energy Group South America Company Limited,Qingdao 266555,China;Exploration and Development Research Institute,Shengli Oilfield Company,SINOPEC,Dongying 257015,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]山东能源集团南美有限公司,山东青岛266555 [3]中国石化胜利油田分公司勘探开发研究院,山东东营257015

出　　处：《中国石油大学学报(自然科学版)》2025年第2期118-130,共13页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家自然科学基金优秀青年项目(海外)(ZX20230152);山东能源集团深层高温地热重大科技项目(HX20230299);国家自然科学基金面上项目(ZX20240185)。

摘　　要：孔弹性介质理论考虑了地下固体基质与孔隙流体的性质,能够比弹性介质理论更加精确地描述地震波在实际介质中的传播情况,但孔弹性介质中存在快纵波、慢纵波以及横波3种基本波型,在传播过程中相互耦合,如果不对其进行分离,会严重降低地震成像的质量。提出一种孔弹性介质真振幅矢量波场分离方法,实现快纵波、慢纵波和横波3种基本波形的完全分离。首先引入一个辅助的泊松方程,将耦合的固相和液相双相介质波场分解为真振幅的纵波和横波矢量波场。然后,基于本征值和本征向量分析,使用一种双外积方法将纵波波场分解为快纵波和慢纵波。结果表明:所提方法具有很高的波场分离精度及可靠性;该方法不仅能够完全分离孔弹性介质中的快纵波、慢纵波及横波,获得的快纵波、慢纵波以及横波均为矢量形式,且其振幅、相位与物理单位均与原耦合波场保持一致。The poroelastic theory considers the properties of both the underground solid matrix and pore fluids,allowing for accurate description of seismic wave propagation in a two-phase medium compared to elastic theory.However,in a poroelastic medium,there are three fundamental wave modes,namely fast P wave,slow P wave,and S wave,which become coupled during propagation.The quality of seismic imaging can be significantly degraded if these modes are not properly separated.In this paper,a true-amplitude vector wavefield decomposition method for poroelastic media is proposed to fully decouple the three fundamental wave modes.First,by introducing an auxiliary Poisson's equation,the coupled wavefields in the solid and fluid phases are decomposed into true-amplitude vector P and S wavefields.Then,a double-cross-product method based on eigenvalue and eigenvector analysis is applied to separate the fast and slow P waves.Model test results confirm that the proposed method achieves high accuracy and reliability in wavefield separation.The results demonstrate that this method can completely separate the fast P wave,slow P wave,and S wave in poroelastic media in vector form while preserving their original amplitudes,phases,and physical units.

关 键 词：孔弹性介质 矢量波场分离 快慢纵波 本征型分析 

分 类 号：P631.4[天文地球—地质矿产勘探]