非对称走时叠前时间偏移方法及应用

The method and application of prestack time migration by non-symmetrical travel time

随着地震资料处理技术的发展,叠前时间偏移越来越普及,并成为一个普通的地震资料处理流程。传统的叠前时间偏移公式都是基于水平层状模型的假设推导而来,在速度横向变化剧烈的介质中不能够达到理想的聚焦效果。本文基于李代数积分方程以及拟微分算子等理论介绍了非对称走时公式,计算公式中由于包含有速度横向导数项,在横向速度变化大的介质中,也能有较高的聚焦效果,而且也为走时计算提供了精确的相对振幅保持权系数。本文从非对称走时概念出发,分析非对称走时原理,通过实例介绍其应用,使之能更好的为石油勘探事业服务。

With the development of seismic data processing technique, prestack time migration is getting more and more popular and has become conventional seismic data processing. The traditional prestack time migration formulas are derived based on the assumption of a layered model, which has no good focusing effects in the media with the great lateral variation of velocity. In the paper, based on Lie algebra and a pseudo-differential operator, The non-symmetri- cal travel time formulas are introduced which can not only get good focusing effects in the media with the great lateral varia- tion of velocity, but also provide accurate relative amplitude preserve weight coefficients for travel time calcula- tion due to the existence of velocity lateral derivative item. The principle of non-symmetrical travel time is analyzed by the concept of non-symmetrical travel time here. The applications are also given by history eases so as to be more useful in oil exploration and development.