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地震子波估计是地震资料处理与解释中的重要环节,它的准确与否直接关系到反褶积及反演等结果的好坏。高阶谱(双谱和三谱)地震子波估计方法是一类重要的、新兴的子波估计方法,然而基于高阶谱的地震子波估计往往因为高阶相位谱卷绕的原因,导致子波相位谱求解产生偏差,进而影响了混合相位子波估计的效果。针对这一问题,本文在双谱域提出了一种基于保角变换的相位谱求解方法。通过缩小傅里叶相位谱的取值范围,有效避免了双谱相位发生卷绕的情况,从而消除了原相位谱估计中双谱相位卷绕的影响。该方法与最小二乘法相位谱估计相结合,构成了基于保角变换的最小二乘地震子波相位谱估计方法,并与最小二乘地震子波振幅谱估计方法一起,应用到了地震资料混合相位子波估计中。理论模型和实际资料验证了该方法的有效性。同时本文将双谱域地震子波相位谱估计中保角变换的思想推广到三谱域地震子波相位谱估计中。
Earthquake wavelet estimation is an important part of seismic data processing and interpretation. Its accuracy is directly related to the results of deconvolution and inversion. High-order spectral (bispectral and tri-spectral) seismic wavelet estimation methods are an important and emerging method of wavelet estimation. However, seismic wavelet estimation based on higher-order spectra often leads to higher order phase spectrum The phase spectrum of the wavelet has a deviation, which affects the effect of the hybrid phase wavelet estimation. In response to this problem, this paper proposes a phase spectrum method based on conformal mapping in the bispectral domain. By narrowing the range of the Fourier phase spectrum, the situation that the bispectrum phase is wound is effectively avoided, thereby eliminating the influence of the bispectrum phase winding in the original phase spectrum estimation. This method combined with the least-squares phase spectrum estimation constitutes the least squares seismic wavelet phase spectrum estimation method based on conformal mapping, and is applied to the seismic data mixed phase Seat wave estimation. The theoretical model and actual data verify the effectiveness of the method. At the same time, this paper extends the idea of conformal mapping in the estimation of phase spectrum of bispectral seismic wave to the estimation of phase spectrum of three-spectrum seismic wavelet.