QT地区层间多次波识别与压制方法

The identification and suppression methods of internal multiples in QT area

QT地区层间多次波发育,干扰有效信号,导致地震资料信噪比降低,影响成像精度。该区层间多次波与一次地震波的波组特征相似,且剩余时差较小,导致其压制困难,因此,成为制约精细勘探的难点之一。基于层间多次波与一次波的差异,首先从CMP(共中心点)道集、速度谱、叠加剖面等方面综合分析多次波的特点,确定其来源、速度及存在范围,然后采用高精度Radon变换法对多次波进行压制。实际应用表明,高精度Radon变换法对QT地区地震资料中的层间多次波具有较好的压制效果,对提高该区地震资料成像精度具有重要意义。

The internal multiples are very developed in seismic data of QT area,which interfere with the effctive signal,reduce the signal-to-noise ratio and affect the imaging accuracy.In this area,the internal multiples and the primary wave are similar in the characteristics of the wave group,and the remaining time difference is small.This similarity makes it difficult for suppression.Therefore,the internal multiple has become one of the difficulties that constrain the fine exploration in this area.Based on the difference between internal multiple and primary waves,firstly,the characteristics of the internal multiple are analyzed from various aspects such as CMP gathers,velocity spectrum and stack section to determine the origin,speed and range.Then,the highprecision Radon transform method is adopted to suppress the multiples.The practical application shows that the high-precision Radon transform method gives a good suppression effect on the internal multiples in the seismic data of QT area,which has great significance to improve the imaging accuracy of seismic data in this area.