基于小波能量谱系图及小波曲线的层序地层划分

Sequence stratigraphy identification based on wavelet energy spectrum and wavelet curve

基于小波变换时频分析,本文探讨了小波基选取的基本原则及小波分析方法划分地层层序的可行性与稳定性,并建立了小波能量谱系图及小波曲线划分层序地层的地质模型。通过对自然伽马曲线进行小波变换,使层序界面上下的能量团表现出间断的响应特征,在小波系数曲线上则表现为明显的高值震荡特征,而对于基准转换面则主要表现为平直的小波曲线,最终根据小波能谱图纵向能量团的组合特征进行区域对比。与传统方法相比,该方法能有效利用测井信号内部结构信息准确地识别层序界面和进行区域地层对比,且具有高效性和可视化特点。

Based on time-frequency analysis of wavelet transform,we discuss in this paper the principle of wavelet base selection,and the feasibility and stability of stratigraphic sequence identified by wavelet analysis.We set up wavelet energy spectrum and geological models of sequence stratigraphy divided by wavelet curves.Through wavelet transform of GR,the energy group around sequence boundary represents discrete response features,and show obvious oscillation of high value on the wavelet coefficient curves,whereas the turnaround surface reflects straight wavelet curves.Thus local correlation can be carried out based on the features embodied by vertical energy group in wavelet power spectrum.Compared with traditional method,this method would make full use of inner structure information of logging signals to identify sequence boundary,and its high efficiency and visualization provide foundations for sequence identification.