基于Wigner-Ville分布与Chrip-Z变换的高分辨时频分析方法

时频分析方法一直广泛地应用于地震数据的处理与资料解释中。针对油气勘探面临的圈闭规模小、储层薄且埋深大、烃源丰富却分布零散等复杂情形时，如果地震资料有效信号频带较窄、分辨率较低，则需高分辨时频分析方法，以提高对微型油气目标的识别精度。平滑伪Wigner-Ville分布（SPWVD）双线性时频分析方法具有良好的时频聚焦性，线性调频Chrip-Z变换（CZT）的螺旋采样插值特性可突出三维空间局部细节。结合此二者优势，形成一种可提高地震信号时频分辨率的新方法（SPWVD-CZT）。该方法通过采样的方式实现数值的插值计算，以增加有效频段的划分点数，完善时频分布的局部细节，在时频域实现频谱信息的细化处理。模拟信号试算和实际地震资料河道微相识别的应用结果表明，该方法能显著提升地震数据时频分析的频率采样率，可为微型地质体的发现及油气开发提供技术支撑。

A new high-resolution time-frequency analysis method based on Wigner-Ville distribution and Chrip-Z transform

The time-frequency analysis method has been widely applied in the processing and interpretation of seismic signals for a long time.At present,the oil and gas exploration is exposed to problems such as the small trap size,thin reservoir thickness,and scattered distribution of rich resources.In addition,with the narrow frequency band and low resolution of effective signals in seismic data,highresolution time-frequency analysis methods are especially required to improve the identification accuracy of small-scale oil and gas targets.The bilinear time-frequency analysis method of smoothed pseudo Wigner-Ville distribution(SPWVD)has good time-frequency focusing,and the spiral sampling interpolation characteristic of Chrip-Z transform(CZT)can highlight the local details of 3 Dspace.By capitalizing on the advantages of the two,we present a new method,i.e.,the SPWVD-CZT method,to improve the time-frequency resolution of seismic signals.The interpolation calculations of signals are achieved by sampling to raise the number of effective frequency division points,improve the local details of time-frequency distribution,and realize the refinement of spectrum information in the time-frequency domain.The application of simulated signal calculation and channel microfacies identification of actual seismic signals shows that the method can effectively improve the timefrequency resolution of seismic signals and develop a new theory for the discovery of small-scale geological bodies and oil-gas development.