基于屏方法的弹性波叠前深度偏移
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摘要
弹性波成像是多分量地震勘探需要解决的关键技术之一。借鉴声波方程中傅立叶有限差分算子中的有限差分补偿方法,对弹性波相屏传播算子进行了大角度校正。在求取成像值时,采用了矢量成像条件,即通过极化矢量,将各分量投影极化方向,然后再成像,从而使波场中的信息得到充分利用,同时解决了P-SV波成像过程中的极性不一致问题。这样,便可以叠加多炮的成像结果,从而提高成像质量。利用模型数据,对大角度相位校正后的弹性屏延拓算子和矢量成像条件进行了试验,成像效果理想。
Elastic wave migration is one of the key technologies of multicomponent exploration. In this paper, the finite-difference compensation in Fourier finite-difference method of acoustic equation is applied to elastic screen propagator. Vector imaging condition is used through calculating polarized vector, and projecting component to polarized direction. It makes the information carried in wave field used efficiently and resolves the polarization issue of P-SV in imaging, which allows partial images from different sources and can be stacked to generate a final image. Finally, elastic screen propagator with wide angle correction and vector imaging condition are tested with model data, and the migration result is ideal.
Elastic wave migration is one of the key technologies of multicomponent exploration. In this paper, the finite-difference compensation in Fourier finite-difference method of acoustic equation is applied to elastic screen propagator. Vector imaging condition is used through calculating polarized vector, and projecting component to polarized direction. It makes the information carried in wave field used efficiently and resolves the polarization issue of P-SV in imaging, which allows partial images from different sources and can be stacked to generate a final image. Finally, elastic screen propagator with wide angle correction and vector imaging condition are tested with model data, and the migration result is ideal.
引文
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[9]SUN R,MCMECHAN G A.Scalar reverse-time depth migrationof prestack elastic seismic data[J].Geophysics,2001,66(5):1519-1527.
[10]HOU A,MARFURT K J.Multicomponent prestack depth mi-gration by scalar wavefield extrapolation[J].Geophysics,2002,67(6):1886-1894.
[11]尧德中.单程弹性波逆时偏移和相移偏移方法[J].石油地球物理勘探,1994,29(4):449-455.
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[14]XIE X B,WU R S.A complex-screen method for modeling elastic wave reflections:Expanded Abstracts[C].SEG65th An-nual Meeting,1995:1269-1272.
[15]XIE X B,WU R S.Multicomponent prestack depth migration using the elastic screen method[J].Geophysics,2005,70(1):S30-S37.
[16]RISTOW D,RUHL T.Fourier finite-difference migration[J].Geophysics,1994,59(12):1882-1893.
[2]CHANG W F,MCMECHAN G A.3D elastic prestack re-verse-time depth migration[J].Geophysics,1994,59:597-609.
[3]田雪丰,张奋轩,曹新领.性波逆时偏移及其成像条件[J].中国煤田地质,2002,14(2):58-61.
[4]张会星,宁书年.弹性波动方程叠前逆时偏移[J].中国矿业大学学报,2002,31(5):372-374.
[5]KUO J T,DAI T F.Kirchhoff elastic wave migration for the case of noncoincident source and receiver[J].Geophysics,1984,49(8):1223-1238.
[6]DAI T F,KUO J T.Real data results of Kirchhoff elastic wave migration[J].Geophysics,1986,51(4):1006-1011.
[7]HOKSTAD K.Multicomponent Kirchhoff migration[J].Geo-physics,2000,65(3):861-873.
[8]ZHE J P,GREENHALGH S A.Prestack multicomponent mi-gration[J].Geophysics,1997,62(2):598-612.
[9]SUN R,MCMECHAN G A.Scalar reverse-time depth migrationof prestack elastic seismic data[J].Geophysics,2001,66(5):1519-1527.
[10]HOU A,MARFURT K J.Multicomponent prestack depth mi-gration by scalar wavefield extrapolation[J].Geophysics,2002,67(6):1886-1894.
[11]尧德中.单程弹性波逆时偏移和相移偏移方法[J].石油地球物理勘探,1994,29(4):449-455.
[12]尧德中.纵横波独立成像的VSP弹性波资料逆时深度偏移[J].物探化探计算技术,1994,16(3):213-217.
[13]XIE X B,WU R S.Modeling elastic wave forward propagation and reflection using the complex-screen method[J].J.Acoust.Soc.Am.2001,109(6):2629-2635.
[14]XIE X B,WU R S.A complex-screen method for modeling elastic wave reflections:Expanded Abstracts[C].SEG65th An-nual Meeting,1995:1269-1272.
[15]XIE X B,WU R S.Multicomponent prestack depth migration using the elastic screen method[J].Geophysics,2005,70(1):S30-S37.
[16]RISTOW D,RUHL T.Fourier finite-difference migration[J].Geophysics,1994,59(12):1882-1893.
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