速度随炮检距变化(VVO)分析

Analysis of velocity variation with offset

地震勘探所面对的地表和地下情况越来越复杂，而勘探目标却要求从地震数据中提取更多、更详细和更精确的信息。为了适应新的情况，在速度分析和动校正处理中，必须考虑到速度随地检距的变化，对双曲线型时距曲线加以改进，形成更接近实际情况的时距曲线。本文在旅行时计算公式中引火炮检距的四次项，并采用速度梯度概念来描述速度随炮检距的变化，阐明了其系数的物理含义，提高了复杂介质速度信息的精度，增加了速度分析结果的信息量，也改善了叠加效果。

Seismic explorati0n faces increasingly complicated surface and subsurface c0n-ditionsj however, the exploration target needs more and more accurate informa-tions. In order to cope with the tough conditions, in velocity ana1ysis and normalmoveout correction, geophysicists must consider velocity variation with offset, andimprove hyperbolic time-distance curve to form more reasonable time-distancecurve. What is more, in this article, a term relating to the fourth power of offset isalso used in travel time computation, velocity gradient conception is taken to de-scribe velocity variation with offset, and the physical meaning of the coefficient isexpounded clearly. As a result, the accuracy of velocity in complicated medium isimproved greatly, and the volume of velocity information is increased obviously-New method betters stack effect.