瞬变电磁场拟波动方程偏移成像  

Quasi wave equation migration of transient electromagnetic field

作　　者：陈本池[1] 李金铭[2] 周凤桐[3] 

机构地区：[1]石油大学 [2]中国地质大学 [3]中国地质科学院物化探研究所

出　　处：《石油地球物理勘探》1999年第5期546-554,共9页Oil Geophysical Prospecting

基　　金：地质行业科学基金!959617

摘　　要：本文提出了一种新的瞬变电磁场偏移成像方法。该方法满足扩散方程的低频电磁场，并可由积分变换转换为满足波动方程的波场，然后直接利用地震偏移成像技术，求取介质的几何参数。文中针对有源二维地电模型，推导出了与瞬变电磁场定解问题相对应的变换波场的定解问题方程，并采用有限差分逆时深度偏移方法，成功地对有源二维瞬变电磁场进行了偏移成像处理，得到了清晰的、与理论模型吻合很好的偏移断面图像。A new migration method for transient electromagnetic field is recommended here. The method is applicable to low-frequency electromagnetic field that is expressed by diffusion equation. In terms of this method, the low-frequency electromagnetic field is converted, using integral transform, into a wave field expressed by wave equation; then, geometric parameters of medium are estimated by using seismic migration technique. For a 2-D geoelectric model with source, the solution equations of converted wave field are deduced, which correspond to those of transient electromagnetic field. By using finite difference reverse-time depth migration,the migration processing of 2-D transient electromagnetic field with source is successfully finished to produce clear migrated section that coincides with theoretical model.

关 键 词：瞬变电磁场 偏移成像 电磁法勘探 波动方程 波场 

分 类 号：P631.34[天文地球—地质矿产勘探] P631.325[天文地球—地质学]