一种“静校不静”现象的分析
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摘要
在我国西部地区由于表层激发接收条件差,常采用高叠加次数的地震观测技术。在地震数据处理中,在进行了地形校正和基准面校正之后,还存在数十毫秒的剩余静态时差。在叠加剖面上,这种静态时差对反射波的起伏形态的影响具有浅中深层的差异性,即出现了“静校不静”的现象。分析表明,这种现象是由叠加次数高、排列偏移距大,在同一个CMP道集中,浅、中、深层参加叠加的道数差异较大,导致叠加过程中对静态时差平滑作用的差异所致。与岩石裸露山区中因反射波传播路径差异形成的非地表一致性“静校不静”现象不同,仍然是“地表一致性”的。分析产生这种现象的原因,为正确进行静校正打下基础。。
In the processing of seismic data from western China, there frequently exists a residual static time difference of tens of milliseconds after elevation and datum corrections. In the stacked profiles, the effects of this static time difference on the shape of the reflection undulation are different in shallow, middle and deep layers, i.e., there exists the phenomenon of "non-static statics". An analysis shows that such a phenomenon is attributed to high stacking multiplicity and large offset in the arrangement. For the shallow, middle and deep layers in the same CMP gather, the number of the traces participating in stacking is quite different, which causes different smoothing actions during stacking on the static time difference. Different from the "non-static statics" phenomenon caused by different propagation paths of the reflection in mountain areas, it remains "surface consistent". The correct analysis of the cause of this type of phenomena provides a basis for the correct application of static correction.
In the processing of seismic data from western China, there frequently exists a residual static time difference of tens of milliseconds after elevation and datum corrections. In the stacked profiles, the effects of this static time difference on the shape of the reflection undulation are different in shallow, middle and deep layers, i.e., there exists the phenomenon of "non-static statics". An analysis shows that such a phenomenon is attributed to high stacking multiplicity and large offset in the arrangement. For the shallow, middle and deep layers in the same CMP gather, the number of the traces participating in stacking is quite different, which causes different smoothing actions during stacking on the static time difference. Different from the "non-static statics" phenomenon caused by different propagation paths of the reflection in mountain areas, it remains "surface consistent". The correct analysis of the cause of this type of phenomena provides a basis for the correct application of static correction.
引文
[1]曹金声.山地地震勘探中的“静校不静”题的讨论[ J].石油物探,1980(3):66-73.
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