高精度频率衰减分析技术及其应用(英文)

本文从含流体孔隙介质中的地震波场的衰减理论出发,对常规的频率衰减分析技术中的"低频阴影"和"频率衰减梯度"分析方法进行了改进,提出了一种高精度的频率衰减分析技术。首先,通过引入三参数小波变换和时频聚焦准则,发展了一种基于自适应三参数小波变换的高精度时频分析方法,其不仅具有很高的时—频分辨率(有利于"低频阴影"分析),而且其频谱只有一个峰,旁瓣比较小(有利于"频率衰减梯度"分析)。其次,采用基于最小二乘法的Nelder-Mead非线性算法对频谱的衰减部分进行拟合计算,可以准确地计算衰减系数,提高了"频率衰减梯度"的计算精度。实际资料的计算结果表明,本文提出的综合"低频阴影"和"频率衰减梯度"方法的频率衰减分析技术能够有效地圈定碳酸盐岩鲕滩储层的发育区域,且两种方法具有很好的一致性,有效地提高了储层预测的可靠性,从而降低了勘探风险。

High-precision frequency attenuation analysis and its application

Based on seismic attenuation theory in a fluid-filled porous medium, we improve conventional methods of low-frequency shadow analysis (LFSA) and energy absorption analysis (EAA) and propose a high-precision frequency attenuation analysis technology. First, we introduce the method of three-parameter wavelet transform and the time-frequency focused criterion and develop a high-precision time-frequency analysis method based on an adaptive three-parameter wavelet transform, which has high time-frequency resolution with benefit to LFSA and can obtain a single-peaked spectrum with narrow side-lobes with benefit to EAA. Second, we correctly compute absorption coefficient by curve fitting based on the nonlinear Nelder-Mead algorithm and effectively improve EAA precision. Practical application results show that the proposed frequency attenuation analysis technology integrated with LFSA and EAA can effectively predict favorable zones of carbonate oolitic reservoir. Furthermore, reservoir prediction results based on LFSA correspond with EAA. The new technology can effectively improve reservoir prediction reliability and reduce exploration risk.