基于零相位子波地层Q值估计

Estimation of layer quality factors based on zero-phase wavelet

地震子波一般并非脉冲,而地层品质因子的提取公式大都是假设地震子波为脉冲时推导得到的,这在实际应用中误差较大,并且在进行频谱比时不容易确定所选择的频率区间的范围,从而影响方法的适用性.由此,本文讨论了地震子波为一般零相位子波时,基于地震波的传播理论和S变换理论,推导了S域中地层品质因子的估算方法,并通过Marmousi2模型和实际资料的应用来验证该方法的正确性和适用性.经模型和实际资料的应用表明,该方法不仅充分考虑了因地层吸收而引起的振幅、频率等信息的变化,避免了通常品质因子计算中的平均效应,而且能够很好的确定估算Q值的频率区间范围,使估算的品质因子更加准确,适用性更强.

Generally the seismic wave is not pulse. But the formulas of the extraction of quality factor is commonly derived by assuming that the seismic wave is pulse. In practical applications the error is larger, and it is not easy to determine the scope of the selected frequency range to do the spectral ratio. Consequently this affects the applicability of the method. Thus, this paper discusses the derivation of the method of quality factor estimation based on seismic wave propagation and S transformation when the seismic wavelet is zero-phase wavelet, and verifies the correctness and applicability by the Marmousi2 model and the application of actual data. The application of models and real data show that, this method not only considers the change of the information of amplitude and frequency caused by earth layer absorption, but also avoid the average effect of the absorption coefficient of the usual calculation. It can determine the frequency range better, making earth layer absorption parameters extraction more accurately and more applicable.