质心频率线性拟合法估算品质因子Q

Quality factor Qestimation based on linear fitting of centroid frequency curve

质心频移法是常用的Q值估算方法。本文基于该方法的变式得到质心频率与传播时间的线性衰减关系。根据该线性衰减式,通过拟合质心频率—传播时间的斜率估算Q值。模型测试表明,在传播时间较短的情况下,线性式对不同震源谱的适用性较好;当激发条件不一致时,线性拟合具有相对较好的鲁棒性。实际资料测试表明,线性拟合法在近地表Q值估算中取得了较好的应用效果。

Quality factor Qis an important parameter of hydrocarbon detection and reservoir characterization, which reflects seismic wave attenuation.Centroid frequency shift(CFS)is one of the most common methods to estimate Q.We derive a new linear formula based on this method in Quality factor Qestimation.In this formula,the centroid frequency of seismic wavelets reduces linearly with the propagation time,and the slope of curve is the reciprocal of Q.Thus,Qvalue can be estimated by fitting the centroid frequency curve of wavelets.Model and real data tests show that the linear relationship does not rely on the shape of source wavelet spectrum,and linear fitting has certain robustness.