【摘要】 针对陆上地震资料处理的静校正问题,提出了一种基于偏移成像道集的剩余静校正方法.与传统的由动校正后的CMP道集中拾取剩余时差不同,本文基于偏移成像道集求取剩余时差,避免了复杂情况下同相轴归位不准确导致的剩余时差拾取误差.通过生成随炮点和检波点位置变化的偏移道集,实现了由偏移道集中直接拾取炮、检点的地表一致性剩余时差;该炮、检点偏移道集只在指定的局部时窗生成,并不增加大的计算量.二维和三维实际数据测试表明了该方法的有效性和实用性.更多还原

【Abstract】 Static correction is a very important topic in land seismic exploration.Field and datum static correction can eliminate time distortions caused by variable elevations of the source and receiver.However,there still exist small time distortions,which may affect the continuity and resolution of events in migration results.So residual static correction is necessary in the conventional static correction processing.Using migrated gathers to pick up the residual time shifts of the shot and receiver,a new residual static corrections method is presented.The method of residual static corrections is used to improve the resolution of pre-stack migration.We obtain the residual time shifts by migrated gathers rather than CMP gathers in the conventional method,which can reduce the artificial picking error by incorrect migration or indistinct events.Firstly,we generate the shot-domain and receiver-domain migrated gathers in the local time window.The de-noised migrated result is used as the reference gathers section.Then,the surface consistent residual time shifts are obtained by the shot-domain and receiverdomain migrated gathers.We need to calculate the residual statics according to shot and receiver positions separately.Same as conventional residual static correction,we pick up the residual time shifts in the migrated gathers by correlation with the reference gathers.After this,we remove the outliers and compute the arithmetic mean of the residual time shifts in each shot and receiver.This wholeprocess can be carried out only in the selected time windows,which can save the calculation obviously.Finally,we put those residual statics of every shot and receiver into data in the migration.We test this method on two field data set examples.One is 2.5Dreal seismic data recorded with a single receiver line.Another is the real data of 3Dacquisition.The proposed method can be used both in 2Dand 3Dfield data sets,which can be easily combined to conventional seismic data processing.The CRP gathers comparison show that this approach improves the quality greatly.The events become more and more continuous and clear.The comparisons of migrated stack section clearly show that by imposing the proposed residual static corrections,we can image clearer faults and more continuous events.After theoretical investigation and real data application,we have the following conclusions:(1)The proposed method is suitable and effective for 2Dand 3Dreal land seismic data.(2)This method can be easily combined with the existing seismic data processing flow.(3)The proposed process flow does not increase amount of computation.(4)The results show the residual static correction based on migrated gathers can obviously improve the S/N and resolution of pre-stack time migration.更多还原