孔隙裂隙地层中偶极声源的横波辐射声场  

Radiation Characteristics of Dipole Shear Wave-Field in Cracked Porous Formation

作　　者：古锐瑶 王莉 陈鸣 曹景记 GU Ruiyao;WANG Li;CHEN Ming;CAO Jingji(Institute of Disaster Prevention,Yanjiao,Hebei 065201,China;CNOOC(China)Limited Zhanjiang Branch Company,Zhanjiang,Guangdong 524057,China;CNOOC Research Institute CO.LTD.,Beijing 100028,China)

机构地区：[1]防灾科技学院,河北燕郊065201 [2]中海石油(中国)有限公司湛江分公司,广东湛江524057 [3]中海油研究总院有限责任公司,北京100028

出　　处：《测井技术》2020年第4期329-333,共5页Well Logging Technology

基　　金：廊坊市科技支撑计划项目(2018011020);中央高校基本科研业务青年项目(ZY20180209)。

摘　　要：孔隙和裂隙通常在脆性岩石中同时发育,影响声波测井过程中声源在地层中的辐射波场。为研究偶极子声源辐射到孔隙、裂隙地层远场中横波能量的空间分布与大小,利用孔隙、裂隙地层波动理论计算不同孔隙度与裂隙密度下SH横波和SV横波的远场辐射图样及不同频率下2种横波的能流大小。结果表明,SH横波能量在井外远场中的空间分布与大小均优于SV横波,起到主导作用。随着地层孔隙度和裂隙密度的增加,SH横波和SV横波的最大能流逐渐减小,且在相同孔隙和裂隙发育度下,最大横波能流随孔隙度的增加衰减更加迅速。Pores and fractures usually develop in brittle rocks at the same time,which affect the radiation wave field of sound source in the formation during acoustic log.To study the shear-wave radiation wavefield excited by a dipole source,the unified theory for elastic wave propagation in cracked porous media is applied in this work.The far field radiation directivities of SH-shear and SV-shear wave with various porosities and crack densities are investigaed,and the SH-shear and SV-shear wave radiation energy flow change rules with source-excited frequency under different pore and crack parameters are also analyzed.The simulation results show that the SH-wave radiation characteristics,in terms of angular coverage and radiation efficiency,are superior compared to that of the SV-wave,playing a dominant role in the radiated wavefield.However,with increasing the formation porosity and crack density,the radiation energy flow maximum values of SH-and SV-shear waves decrease.Under the same porosity and fracture development degree,the maximum shear wave energy flow decays more rapidly with the increase of porosity.

关 键 词：偶极横波远探测测井 孔裂隙介质 孔隙度 裂隙密度 偶极声源 横波辐射声场 

分 类 号：P63184文献标识码:A[天文地球—地质矿产勘探]