基于几何级数展开的鬼波压制方法

海上拖缆地震数据采集,检波器位于海平面以下,由于海平面的反射作用,检波器接收到的除了上行的一次波,还包括下行的鬼波,因为一次波和鬼波的干涉作用,导致地震信号的有效频带变窄,分辨率降低。为了恢复信号的有效频带,需要进行鬼波压制的宽频处理。该文提出了一种基于逆鬼波算子几何级数展开的鬼波压制技术。几何级数的每一项都是一个波场传播算子,级数的叠加可以实现鬼波的压制,通过对几何级数的截断,可以得到只含上行波的反射信号。数值算例证明了该文方法的有效性,因为波场延拓算子在频率波数域进行,借助快速傅里叶变换,该文方法的效率很高。

Seismic deghosting based on geometric series expansion

Deghosting is a longstanding problem in marine seismic processing. Due to the presence of the free-surface, the interference between up- and down-going wavefields are present in the recorded data, resulting in notches in the amplitude spectrum of the recorded data. This leads to a reduction of the useful frequency bandwidth and therefore damages seismic resolution. It is desirable to remove the ghost events from the recorded data to gain broader bandwidth data. In this paper, we propose a deghosting method based on the geometric series approximation of the inverse ghost operator. Each item of the geometric series can be viewed as wave field propagation operator. The superposition of this series can achieve ghost suppression. By truncating the geometric progression, a reflected signal containing only the upward wave can be obtained. Numerical examples demonstrate the effectiveness of the proposed method. Because we can perform wavefield extrapolation in the FK domain. This method is also efficient by the use of FFT