【摘要】 浅海海底起伏和速度变化对OBC资料成像质量产生较大影响。建立浅海海底表层速度模型不仅能够解决OBC资料的静校正问题,也可用于海底反射系数计算、双检资料合并、多次波压制等,但是,目前针对浅海海底表层速度建模的研究还不多。文中提出了针对浅海地区OBC资料的海底表层速度建模的三维初至走时反演技术,主要包括:(1)震源位置校正技术。根据地震波在海水中传播特征,把在海水中激发的震源位置校正至海底,使震源和接收点都位于海底,利于初至走时反演计算;(2)快速三维初至走时反演方法。利用回折波走时和射线方程,形成了高效率初至走时反演方法。将该技术应用于胜利油田莱州湾浅海区海底OBC资料的处理中,建立了三维海底表层速度模型,用此速度模型进行静校正,取得了良好的应用效果。更多还原

【Abstract】 The topographic relief of seabed and the velocity of sub-seabed layers have great influence on imaging quality of OBC data.Estimating sub-seabed velocity models in shallow sea areas can be used not only for static correction of OBC data but also for calculation of such objects as seabed reflection coefficients,merging of OBC dual-geophone seismic data,and multiple suppression. However,there are few velocity model building methods using OBC seismic data in shallow sea areas.In this paper,the authors propose a 3-D subseabed velocity model building method using the first arrival times of OBC data in shallow sea areas.The new method includes shot positions correction and fast 3-D velocity inversion method using first arrival times. For the convenience of velocity model inversion,shot points are moved from their original positions to the seabed according to the diving wave ray equation.The fast 3-D velocity inversion method using the diving-wave first arrival times and offset information doesn’t need ray tracing.So the new method is faster than the traditional ray tracing inversion methods. The authors applied this method to the field OBC seismic data acquired in shallow sea of the Shengli Oilfield.The static correction of OBC seismic data was performed using the inverted velocity method and the results show that the method is correct and effective.更多还原