振幅谱补偿和相位校正

AMPLITUDE SPECTRA COMPENSATION AND PHASE CORRECTION

本文探讨了频域两步法子波处理,即振幅谱补偿和相位校正的原理及其实现。振幅谱补偿的目的是在地震记录可靠频带范围内恢复反射系数的振幅谱。具体实现采用了多道谱平均法,以正确估算地震子波的振幅谱。从记录中消除子波振幅谱影响之后,进而对记录振幅谱作高频增强处理,使之逼近于实际反射系数的振幅谱。相位校正的目的在于消除子波剩余相位的影响,方法基于常相位假设。最佳相位判别依据是最大方差模准则和实际测井资料,通过相位扫描进行自动拾取。把这种方法用于合成声波测井技术,可明显改善反演结果与实际测井曲线的符合程度;文中也给出了这方面的应用实例。

This paper deals with the theory and implementation of the two-step approach for wavelet processing in frequency domain, which can be interpreted as amplitude spectra compensation and phase correction. The purpose of compensating amplitude spectra is to recover the amplitude spectra of reflection coefficients within the range of dependable frequency band of seismic record. The specific measure taken is to average the multiple channel spectra so as to estimate correctly the amplitude spectra of seismic wavelets. First step is to remove the effect of wavelet amplitude spectra from the record and then proceeds to have the amplitude spectra of record processed with high frequency enhancement so that to gear it approximating to the amplitude spectra of actual reflection coefficients.The phase correction is aiming at getting rid of the affects from the residual phase of wavelets, which is based on the-presumption of phase being constant. The criteria to determine the optimum phase include the maximum variance norm and real log data. Phases are picked up automatically using phase sweeping. By applying this method to synthetic acoustic log technique, distinct improvement is shown on the coincidence between inversion and real log data. Also, examples in this connection are given in the paper.