瞬变电磁场拟波动方程偏移成像
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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.
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.
引文
1 Lee S, Memechan G A Phase-field imaging: The electromagnetic equivalent of seismic migration.Geop-hysics, 1987, 52(5): 678～693
2 Yutuka,Sasaki. Application of phase-shift migration to magnetotelluric data. Presented at the 59th annu-al international SEG meeting,1989
3 Zhdannov M S,Frenkel M A.The solution of the inverse problems on the basis of the analytical continu-ation of the transient electromagnetic field in reverse time.J Geomag Geoelectr,1983,35:747～765
4 Zhdannov M S,Traynin P N.Resistivity imaging by time domain electromagnetic migration.ExplorationGeophysics,1995,26:186～194
5 王家映.一维大地电磁资料的直接反演法.地质科技情报,1987,(6):104～113
6 沈飙,何继善.仿用反射地震处理MT资料反演的理论探讨.物探与化探,1991,(5)
7 魏胜,王家映.二维模型中的MT资料的偏移.地球物理学报,1993,(3)
8 Lavrent’ev M M,Romanov V G. Ill-posted problems of mathematical physics and analysis(in Russian).Nauka,1980
9 陈本池.瞬变电磁场的波场变换与偏移成像理论研究.中国地质大学博士学位论文,1998
10 Loewenthal D.The wave equation applied to migration. Geophysical Prospecting,1976,24(2):380～417
11 陆金甫.偏微分方程的数值解法,清华大学出版社,1989
12 Reynolds A C.Boundary conditions for the numerical solution of wave propagation problems. Geophysics,1978,43(6)1099～1110
2 Yutuka,Sasaki. Application of phase-shift migration to magnetotelluric data. Presented at the 59th annu-al international SEG meeting,1989
3 Zhdannov M S,Frenkel M A.The solution of the inverse problems on the basis of the analytical continu-ation of the transient electromagnetic field in reverse time.J Geomag Geoelectr,1983,35:747～765
4 Zhdannov M S,Traynin P N.Resistivity imaging by time domain electromagnetic migration.ExplorationGeophysics,1995,26:186～194
5 王家映.一维大地电磁资料的直接反演法.地质科技情报,1987,(6):104～113
6 沈飙,何继善.仿用反射地震处理MT资料反演的理论探讨.物探与化探,1991,(5)
7 魏胜,王家映.二维模型中的MT资料的偏移.地球物理学报,1993,(3)
8 Lavrent’ev M M,Romanov V G. Ill-posted problems of mathematical physics and analysis(in Russian).Nauka,1980
9 陈本池.瞬变电磁场的波场变换与偏移成像理论研究.中国地质大学博士学位论文,1998
10 Loewenthal D.The wave equation applied to migration. Geophysical Prospecting,1976,24(2):380～417
11 陆金甫.偏微分方程的数值解法,清华大学出版社,1989
12 Reynolds A C.Boundary conditions for the numerical solution of wave propagation problems. Geophysics,1978,43(6)1099～1110
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