【摘要】 品质因子Q是表征地层吸收衰减特性的重要参量,可用于储层预测和油气检测。质心频移法(Centroid Frequency Shift,CFS)是稳定性较高的Q值估算方法,但理论精度较依赖于高斯谱假设,存在一定的不足。为了给出更精确的理论公式,提出了基于谱模拟的质心频移估算方法,具体步骤如下:1利用N次加权指数解析式对初始地震子波谱进行拟合,得到子波参数;2估算不同时刻地震子波谱的质心频率(主频);3根据质心频率与谱拟合参数之间的解析关系,反演待定参量,并估算地层Q值。模型测试结果表明,对于光滑子波谱,基于谱模拟的质心法能较好地突破常规方法的理论假设局限,提高估算精度。实际资料应用结果表明,该方法估算的Q值符合地层趋势,具有较好的可信度。更多还原

【Abstract】 Quality factor is an important parameter of hydrocarbon detection and reservoir characterization,which represents the seismic wave attenuation in the formation.Centroid frequency shift(CFS)is a more stable method to estimate Q,but there is a shortage in theoretical precision,which over depends on the assumption of Gauss spectrum.A new method is proposed to give more precise theoretical equation in this paper.Firstly,multi-parameters analytic expression that is used to fit initial seismic wave spectrum and wavelet parameters are obtained.Secondly,centroid frequencies of seismic wavelet spectrum at different time are estimated.Finally,based on analytic relationship between centroid frequency and spectrum fitting parameters,Qis estimated by solving some parameters.Model test shows that CFS of spectrum fitting could overcome the disadvantages of theoretical assumption for the smooth spectrums and enhance the accuracy of estimation.The field seismic data test shows that the reliability of new method is higher and the Qestimates accords with stratum trend.更多还原