提高逆时偏移成像精度的叠前插值处理研究与应用

Seismic wave pre-stack interpolation processing for improving the precision of reverse-time migration and its application

为了提高叠前逆时偏移成像精度,开展了针对逆时偏移的地震资料预处理方法研究——叠前插值处理。从Marmousi理论模型出发,对模拟的理论炮集数据进行抽稀,在满足数值频散关系条件下进行叠前逆时偏移处理,计算结果表明,炮集记录道间距增大会引入线性干扰,较大程度影响了逆时偏移结果的精度和横向连续性;从实际三维地震资料数据出发,对比分析了沿检波线方向和沿检波站方向进行叠前频率-空间域三维插值前、后的数据和对应的逆时偏移结果。研究表明,未进行叠前插值处理的逆时偏移剖面存在类似于理论数据抽稀情况下的线性干扰,同相轴的连续性差;而经插值处理后,插值地震道的同相轴过渡自然无畸变,对应的逆时偏移剖面连续性明显增强,线性干扰得到有效压制。因此,叠前插值处理能够有效提高高信噪比地震工区资料的逆时偏移成像精度。

In order to improve the precision of the seismic wave pre-stack reverse-time migration,we carry out the study on pre-stack interpolation processing method.In the paper,started from the Marmousi model,the synthetic theoretical common shot gathers are sparsely extracted,and the reverse-time migration is carried out with the condition of the numerical dispersion relationship.The computational results show that increasing channel spacing for common shot gather will bring in linear noise,which largely affects the precision of reverse-time migration and lateral continuity of reflection events.Then,on the basis of real 3Dseismic data,the data and their corresponding reverse-time migration results before and after prestack frequency-spatial domain 3Dinterpolation processing along receiver station direction and along receiver line direction are compared.The results indicate that the reverse-time migration section without interpolation processing displays bad continuity and linear noise which is similar to the theoretical data after sparse extraction.After interpolation processing,there is no distortion and the seismic event is natural in the common shot gather and in the corresponding reverse-time migration section.Meanwhile,the continuity of seismic event is greatly improved,and the linear noise is effectively suppressed.Therefore,the pre-stack interpolation processing can effectively improve the reverse-time migration precision of high S/N seismic data.