地震波横波分裂现象的数值模拟特征  

Numerical simulation of characteristic research on seismic shear wave splitting

作　　者：全红娟[1,2] 朱光明[1] 李桂花[3] 

机构地区：[1]长安大学地质工程与测绘学院,陕西西安710054 [2]长安大学理学院,陕西西安710064 [3]山东科技大学地质科学与工程学院,山东青岛266590

出　　处：《西北大学学报（自然科学版）》2014年第5期745-750,共6页Journal of Northwest University（Natural Science Edition）

基　　金：国家自然科学基金资助项目(413741269);中央高校专项基金资助项目(CHD2011JC193;2014G1121095)

摘　　要：开展了横波分裂的机理、横波分裂的影响因素及横波分裂的可识别条件等3个方面的研究。采用交错网格高阶有限差分法,对垂直裂缝介质中地震波的传播特征进行了数值模拟。研究结果表明:由于入射横波在裂缝介质中存在两个正交极化分量导致横波分裂现象的发生。横波分裂的因素与震源、传播介质、分界面、观测系统等有关。横波分裂可识别的条件是:采用剪切力源或集中力源及VSP或井间地震观测系统,更容易识别横波分裂现象;对于非均匀各向异性介质,如果观测方位合适,会观测到横波分裂和再分裂现象,该项工作对实际中裂隙检测和地震波多波多分量勘探有一定的理论指导意义。Shear wave exploration is an effective way of reservoir geology survey because it can speculate underground fracture situation according to shear wave splitting.This paper carries out the discussion on the mechanism,the influence factors and identifiable conditions of shear wave splitting in order to study fast and slow wave propagation characteristics in fracture media.It performs many numerical simulations for propagation feature of seismic wave in facture media by staggered-grid finite difference method.Incident shear wave exists two orthogonal polarization components so as to produce shear wave splitting.The factors of shear wave splitting are concerned with seismic source,propagation media,interface and recording geometry etc.Identifiable conditions of shear wave splitting is adopting shear source or concentrated force source and VSP or seismic cross-hole recording geometry AS for heterogeneous anisotropic media,shear wave splitting and shear wave splitting again is observed with proper azimuth,this work has certain theory instruction significance for seismic explorer to detect fracture and multi-wave and multi-component development in actual exploration.

关 键 词：裂缝介质 横波分裂 井间地震 

分 类 号：P315.3[天文地球—地震学]