二维变速偏移成图系统

Mapping system of 2D variable velocity migration

1. 中国石油地球物理勘探局研究院,河北涿州072750;2. 冀东油田研究院,河北唐山063004

Research Institute of BGP, Zhuozhou 072750, China

地震波的传播速度, 可表示为地层中各点坐标的函数, 即ν=f(x, y,z)。影响速度的因素很多, 如岩性、地层时代、构造发展史等, 因此速度的横向变化是不可忽视的。用统一的速度解决地质问题已不适应勘探的要求。变速处理地震剖面已经实现, 但在解释上变速成图是个难题, 其主要困难是如何进行变速空间归位。二维变速偏移成图系统从客观的地下构造几何形态着手, 根据真实的视深度, 进行变速偏移空间归位, 从而实现变速成图。

The velocity of seismic wave is a function of points in a stratum, that is ν=f(x, y,z).Velocity field is influenced by many factors such as lithology, geologic age, and history of tectonic evolution. Because the lateral variations of velocity cannot be ignored, a unitary velocity will certainly fail to resolve the geological problem. Seismic data processing with variable velocity has been realized. But to produce a correct structure map using variable velocity is still a difficult problem. The key to the problem is how to migrate structures to their correct spatial positions. Mapping system of 2D variable velocity migration achieves velocity-variant mapping by migrating structures according to the subsurface structure and the true apparent depths of structures.