并联f-k偏移
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摘要
在复杂构造区作岩性研究，要求纵、横向速度变化区的地震资料经偏移处理后能得到陡倾角与断层的清晰成像，而以往的Stolt偏移、拉伸f－k偏移以及串联f－k偏移等方法都有其局限性，无法满足上述要求。为此，本文提出了一种新的快速偏移法──并联f－k偏移。其实现过程是，首先由Gazdag相移法与Stolt偏移法之间的关系，导出与陡倾角有关的成像速度；然后利用成像速度作一组常速Stolt偏移，生成一个偏移数据集；再对这些偏移后的数据作适当插值便可得到等效于Gazdag相移法的偏移结果。这种算法是高度并行的，尤其适用于多CPU并行计算机系统。在偏移数据集内插值构造实际变速剖面时，交互方式是一种最佳选择。实际应用表明，该法可适应速度的纵、横向变化，能使陡倾角清晰成像，且具有成像效果好、信噪比高、计算费用少等优点。
The lithology analysis in complicated structure area requires that a migratedseismic section in the area where seismic velocity varies laterally and vertically dis-plays clear images of steep structure and fault;but the Stolt,stretch f-k and cascad-ed fk migrations fails to meet the above requirement because of their Iimitations.Thus parallel fk migration,a new fast migration,is put forward in the paper. It in-cludes the following steps:. Derive steep dip-dependent image velocity from the relati0nship betweenGazdag phase migration and Stolt migration;. Apply the image velocity to a group 0f constant-velocity Stolt migration toproduce a set of migrated data;. The proper interp0lation of the migrated data brings a migration resultequivalent to that of Gazdag method.The method is highly parallel and it is particularIy suitable to multi-CPU paral-lel computer system. Interactive mode is the best option in real varied velocity sec-tion construction which is achieved by making the migrated data interpolati0n. It isshown that the method is applicable to the situation where velocity varys laterallyand vertically, and results in clear high-steep image, good image effect, high signal/noise ratio, less processing cost, etc.
The lithology analysis in complicated structure area requires that a migratedseismic section in the area where seismic velocity varies laterally and vertically dis-plays clear images of steep structure and fault;but the Stolt,stretch f-k and cascad-ed fk migrations fails to meet the above requirement because of their Iimitations.Thus parallel fk migration,a new fast migration,is put forward in the paper. It in-cludes the following steps:. Derive steep dip-dependent image velocity from the relati0nship betweenGazdag phase migration and Stolt migration;. Apply the image velocity to a group 0f constant-velocity Stolt migration toproduce a set of migrated data;. The proper interp0lation of the migrated data brings a migration resultequivalent to that of Gazdag method.The method is highly parallel and it is particularIy suitable to multi-CPU paral-lel computer system. Interactive mode is the best option in real varied velocity sec-tion construction which is achieved by making the migrated data interpolati0n. It isshown that the method is applicable to the situation where velocity varys laterallyand vertically, and results in clear high-steep image, good image effect, high signal/noise ratio, less processing cost, etc.
引文
1Beasley C J,Lynn W,Lrner K and Nguyen H.Cascaded f-k migration. Geophysics, 1988,53(7):881～893
2Brzostowski M B and Black J L.High-dip time migration. Expanded abstracts of 60th SEG Myg,1990
3Kim YC,Gonzalez R and Berryhill J R.Recursive frequency-wavenumber migration. beophyszcs, 1989,54(3):319～329
4Lee jla ju and Byun Bok S.Senslbility of migrational mode to the velocity. Expanded abstracts of 57thSEG Mtg, 1987
5Mikulich W and Hale D. Steep-dip v(z) imaging from an ensemble of Stolt like migrations. Geophysics,1992,57(1):51～59
2Brzostowski M B and Black J L.High-dip time migration. Expanded abstracts of 60th SEG Myg,1990
3Kim YC,Gonzalez R and Berryhill J R.Recursive frequency-wavenumber migration. beophyszcs, 1989,54(3):319～329
4Lee jla ju and Byun Bok S.Senslbility of migrational mode to the velocity. Expanded abstracts of 57thSEG Mtg, 1987
5Mikulich W and Hale D. Steep-dip v(z) imaging from an ensemble of Stolt like migrations. Geophysics,1992,57(1):51～59
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