① 成都理工大学油气藏地质及开发工程国家重点实验室,四川 成都 610059;
② 成都理工大学信息工程学院,四川 成都 610059;
3 四川省成都市成都理工大学信息工程学院地球物理与信息技术系,61009
Numeric simulation and detection of low frequency shadow
Chen Xue-hua1,2,3, He Zhen-hua1, Wen Xiao-tao2, Huang De-ji2
1. State Key Lab Oil and Gas Reservoir Geology and Exploration, Chengdu University of Technology, Chengdu City, Sichuan Province, 610059, China;
2. College of Information Engineering, Chengdu University of Technology, Chengdu City, Sichuan Province, 610059, China
Abstract：In order to study the correlation between low frequency shadow and oil/gas reservoir, the paper extends the 1D viscous wave equation to 3D viscous wave equation and deduced wavefield continuation formula in frequency-wavenumber domain. Using viscous wave equation for numeric simulation of low-frequency shadow for fluid-saturated geologic model discovered that it can describe event time-shift, phase distortion, dominant-frequency lowering, amplitude attenuation and low-frequency shadow caused by diffusiveness, viscosity and velocity dispersion. The good time-frequency analysis method is the key for low frequency shadow detection. The wavelet can be adjusted according to concrete application of signal processing by introducing two parameters to reform the wavelet function in S transform; construction of generalized S transform has optimum and flexibly adjustable time-frequency gathering property, which canimplement the high-efficient instantaneous spectrum decomposition of 3D seismic data. The paper used generalized S transform to carry out instantaneous spectrum decomposition of practical 3D seismic data, which not only can detect the low frequency shadow of oil/gas reservoir, but also can describe lithologic boundary and spatial distribution of oil/gas reservoir, reducing multi-solution of oil/gas reservoir detection
