拉东域基于最小二乘反演的斜缆数据鬼波压制方法

De-ghosting of variable-depth streamer data based on least squares inversion in Radon domain

斜缆采集资料中鬼波的陷频特征限制了地震记录的频带宽度和分辨率,给地震资料反演、解释带来困难。通过压制鬼波,可获得高分辨率的宽频数据。基于拉东域的水平拖缆鬼波压制方法,结合斜缆鬼波随偏移距变化的特点,推导出一次波和鬼波在频率-拉东域的逆变换算子,建立检波器处总波场和海表面处上行波场之间新的关系式,利用最小二乘反演精确求解获得海表面处上行波场,并延拓得到拖缆处鬼波压制后的记录。通过考虑鬼波延迟时间受偏移距和出射角的影响,弥补鬼波延迟时间估计中存在的误差,无需进行反演迭代求取最优鬼波延迟时间,提高了计算效率。合成数据及海上实际斜缆数据测试结果表明,研究方法能较好地压制鬼波,达到拓宽地震记录频带的目的。

The ghost notches limited the frequency bandwidth and resolution of seismic records in variable- depth streamer data, which increase the difficulties of inversion and interpretation of seismic data. By suppressing the ghost, high-resolution broadband data can be obtained. Based on the de-ghosting method of flat-streamer in Ra-don domain, combining the characteristics of the ghost varied with offset, the authors derive the inverse transform operator for primary wave and ghost wave in frequency-Radon domain and build the new relationship between the to-tal wavefield at the cable and the up-going wavefield at the sea surface. The up-going wavefield at the sea surface can be calculated by the least squares inversion method, and can be extrapolated to obtain the deghosted data at the cable. By considering the influence of emerging angle and offset on the ghost delay time, the error in the ghost de-lay time estimation is compensated. This method does not need to perform inverse iteration to obtain the optimal ghost delay time, which improves the computational efficiency. Test results on synthetic and field data show that the proposed approach can remove ghost better and broaden the bandwidth of seismic data.