利用伪Margenau-Hill分布提取地震波能量衰减梯度

Estimation of seismic wave energy attenuation gradient based on Pseudo-Margenau-Hill distribution

地震波在聚集了石油、天然气的储层中传播时存在能量的剧烈衰减,且频率越高能量衰减越快,所以通过地震波高频端能量衰减梯度可以灵敏地检测地层中是否存在烃类流体。通过传统的傅里叶变换求取地震波能量衰减梯度面临诸多问题,而伪Margenau-Hill(PMH)分布作为科恩类时频分布的一种则具有许多优良的特性:真边缘性、弱支撑性、好的时频聚集性等。为此,该文将PMH分布的时频分析方法引入到了地震波吸收衰减分析技术中,利用地震波高频端能量与其对应频率的拟线性关系来计算各时刻的地震波能量衰减梯度。实际资料应用表明,利用PMH分布来求取地震波能量衰减梯度在储层预测中具有重要意义。

It is stated that the propagation of seismic wave in oil gas reservoirs is accompanied by intense energy attenuation, and the frequency component is higher, the energy will be absorbed more. Thus energy attenuation gradient can be used to detect hydrocarbon sensitively. Conventional Fourier transform suffers from time-frequency resolution problems, while Pseudo-Margenau-Hill distribution has many favorable properties, such as time-frequency marginal distribution, ＂weak＂ finite support, time-frequency location, which is one of Cohen class time-frequency distribution. The time-frequency analysis based on Pseudo-Margenau-Hill distribution is presented for energy attenuation gradient estimation, and the log of energy and frequency of higher band is used to calculate the energy attenuation gradient. The practical application shows the effectiveness of the method in hydrocarbon reservoir prediction.