摘要
海上三维地震数据采集中,地震数据的欠采样问题使得目前大多数的鬼波压制方法的效果受到限制。针对欠采样三维海上地震数据,通过波场外推原稀疏采集的地震波场来重建指定位置的密集地震波场,利用不同位置密集波场,通过回响分离方法求解水面密集鬼波波场,进而求解原始位置的稀疏鬼波波场来解决鬼波压制问题。该方法能够兼顾三维数据欠采样问题和鬼波压制问题,从三维意义上遵循地震波的传播规律,目标是最小化实际数据与模拟波场之间的差异,解决密集采样波场稀疏外推问题的不确定性,最终达到压制鬼波、改善地震资料品质的目的。理论数据试算和实际数据处理结果表明,基于密集采样波场重建的三维地震数据鬼波压制方法可以很好地解决三维海上地震数据的欠采样问题对鬼波压制效果的影响,从而很好地压制鬼波,改善地震资料波场品质,提高地震资料分辨率。
The air-water interface is a strong reflector.Therefore,the downward reflection of acoustic waves at the water surface forms a well-known ghost effect in marine seismic waves.In marine surveys,ghost notches on the frequency spectrum reduce the frequency bandwidth and resolution of seismic records,distort waveforms,obscure the identification of events,and increase the difficulty of inversion and interpretation of seismic data.Deghosting seismic data is a longstanding challenge and has become appealing to researchers studying seismic imaging.Berkhout proposed a deghosting method based on echo-deblending,highlighting the similarities between deghosting and deblending,and suggested implementing a technique similar to deblending in simultaneous source seismic waves to separate ghost waves.In marine 3D data acquisition,undersampling seismic data reduces the effectiveness of the present deghosting methods.For 3D marine seismic data,the challenges of deghosting comprise two phases involving handling the wavefield undersampling issue,followed by actual ghost signal removal.To address the undersampling problem of 3D seismic data,Berkhout suggested interpolating seismic data before applying echo deblending to suppress ghosts.In this study,we proposed a 3D-deghosting algorithm for undersampling seismic data based on Berkhout s research.Our algorithm simultaneously addressed the undersampling and deghosting problems.The deghosting method for 3D seismic data based on densely sampled wavefield reconstruction did not use prior interpolation but extended the Berkhout method to establish a dense ghost wavefield on the water surface.It used Lasso regression to solve the problem of sparse extrapolation of the dense wavefield.Our algorithm first reconstructed the dense seismic wavefield at a specified surface by extrapolating the original sparse seismic wavefield.The dense ghost wave field at the water level was calculated using the dense wave fields and the echo-deblending approach.The sparse ghost wave field at the original acquisition position was then obtained.The ghost waves were subtracted from the original data using the least-squares method to resolve the deghosting problem.The goal was to minimize the difference between the actual data and the simulated wavefield,solve the uncertainty of this problem,achieve deghosting,and improve the characteristics of the seismic data.Synthetic data testing and real data processing showed that the deghosting of 3D seismic data based on dense field reconstruction could effectively separate ghost waves,improve wave field characteristics,and improve the resolution of the seismic data.
作者
张庆淮
王明星
吴安楚
朱立彬
陈吴金
ZHANG Qinghuai;WANG Mingxing;WU Anchu;ZHU Libin;CHEN Wujin(International Department,Sinopec Geophysical Corporation,Beijing 100020,China;College of Marine Geosciences,Ocean University of China,Qingdao 266100,China;R&D Center,Sinopec Geophysical Corporation,Nanjing 211102,China)
出处
《石油物探》
CSCD
北大核心
2023年第4期623-632,共10页
Geophysical Prospecting For Petroleum
基金
中石化地球物理公司技术攻关课题(SGC202207/SGC202301)资助。
关键词
波场重建
波场外推
回响分离
套索回归
鬼波压制
欠采样问题
提高分辨率
wavefield reconstruction
wavefield extrapolation
echo deblending
lasso regression
deghosting
undersampling
improved resolution
