Subtle discontinuity detection with nonlinear variable-time window coherency algorithm
Cai Hanpeng1, Hu Guangmin1, He Zhenhua2, Wang Meng3, He Xilei2
1. School of Resources and Environment, University of Electronic Science and Technology, Chengdu, Sichuan 611731, China;
2. Complex Oil & Gas Reservoir Geophysical Institute, Chengdu University of Technology, Chengdu, Sichuan 610059, China;
3. Geophysical Exploration Company, Chuanqing Drilling Engineering Co. Ltd., CNPC, Chengdu, Sichuan 610213, China
Abstract：To enhance coherence cube in subtle discontinuity characterization on seismic data, we propose a nonlinear variable-time window coherence algorithm. Compared with the conventional eigen structure-based coherence computations(C3), the proposed algorithm includes three key parts:A. The instantaneous center frequency, calculated via time-frequency analysis, is used to determine adaptively time-window length for calculating coherence attribute; B. Kendall rank correlation analysis, instead of Pearson correlation analysis, is employed to construct the positive definite matrix for calculating coherence attribute; C. Information divergence is defined as coherence measurement of the analysis point. Experiment results show that the proposed algorithm suppress low-coherence strip phenomenon along seismic event, enhance 3D structural and stratigraphic subtle discontinuity characterization, and improve calculation efficiency.
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