速度倒转与含油气关系分析

地震波速度是地球物理勘探和开发中不可缺少的一项重要参数。随着地震勘探技术的不断提高和发展，许多新方法的不断出现及在地球物理勘探中的应用．地震速度起着越来越重要的作用。地震波的速度受许多因素的影响，这些影响因素一方面给地震解释带来了副作用，另一方面它也为识别和发现油气提供了参考依据。本文通过对叠前地震速度谱信息的分析，在排除了多次波等因素对速度谱上极值点的影响后，发现该区速度谱上出现的速度突然减小，这种现象在横向上有一定的延续性，这一特征与含油气的砂体密切相关。在对雅克拉地区三道桥三维工区的叠前速度谱精细解释中，发现在S53井周围的速度谱上存在速度倒转现象．经过分析这一现象正好处于S53井的含油气层段，从而证实了该特征与含油气地层有着密切关系。

ANALYSIS OF RELATIONSHIP BETWEEN VELOCITY REVERSION AND OIL-GAS

Seismic velocity is an important parameter in geophysical prospecting and development. With the increasing development of seismic survey technology, and with the introduction of many new methods in the geophysical prospecting application, seismic velocity is playing a more important role. Seismic velocity is affected by many factors which bring sometrouble to the interpretation, but at the same time it is used as references for distinguishing and discovering oil and gas. By the analysis of pre-stack seismic velocity spectrum information, after removing the effect of factors on peak value of the velocity spectrum it is found that there is a sudden velocity decrease in the velocity spectrum and it spreads within a limited region, which is closely related to the oil-bearing sand body. In the fine explanation of the pre-stack velocity spectrum in the three dimensional work areas in Sandaoqiao of Yakela, it is found that the velocity reversion exists on the velocity spectrum around the S53 well. Through analysis, it exists just in the oil & gas-bearing layer, which proves that such a character is in close relation to oil-bearing layers.