准噶尔盆地边缘山区的初步静校正

Preliminary static correction in moutain areas around Zhunger Basin

1. 同济大学, 上海200092;2. 新疆石油管理局地调处, 乌鲁木齐830011

Department of Marine geology, Tongji University, Shanghai 200092

本文讨论了准噶尔盆地边缘山区替代速度对初步静校正精度的影响。通过用相遇法[1]从多次覆盖反射地震采集记录中的初至折射波计算基岩面的t₀时和选用合适的替代速度进行初步静校正, 在很大程度上消除了表层不均匀和基岩面起伏引起的大静校量, 使静校误差控制在自动静校的要求范围之内、从而提高了速度谱和水平叠加剖面的质量。

This paper investigates how the selection of weathering zone velocities is in control of static correction in moutain areas around Zhunger Basin. The paper proposes to calculate the to value for a bedrock Just beneath the weathering zone by making use of firstbreaks extracted from a reciprocal obserxration in a seismic multiple coverage system. In that case, as long as a good weathering velocity is selected, high magnititude statics caused by the inhomogeneity near surface and the undulation of the bedrock are reduced to a great extent so as to make the errors in static correction to be confined within an extent as required by the automatic static correction. As a consequence, the velocity analysis and horizontal stacking processing that follow are definitely improved.