Modeling of anisotropic parameters based on HTI medium travel-time inversion and AVAZ inversion
ZHOU Cheng1, YANG Yuyong1,2, ZHOU Huailai1,2, WANG Yuanjun3, TAO Bocheng1, YU Peilin1
1. School of Geophysics, Chengdu University of Technology, Chengdu, Sichuan 610059, China; 2. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu, Sichuan 610059, China; 3. China West Normal University, Nanchong, Sichuan 637002, China
Abstract:Traditional methods for anisotropic inversion primarily rely on well logging data and layer information to construct initial models through interpolation, resulting in low model accuracy. To address this issue in establishing the initial model of seismic anisotropic inversion, under the assumption of horizontal transverse isotropy(HTI) medium, the travel-time information from offset vector tile(OVT) data is utilized to extract anisotropic parameters(ε and δ). Then, another anisotropic parameter γ is estimated based on the empirical relationship between the anisotropic parameters, so as to establish an initial anisotropic parameter model. Furthermore, an initial elastic parameter model is established by using the elastic parameters obtained from isotropic inversion. Finally, On the basis of the Rüger approximation formula for reflection coefficients, the elastic parameters and anisotropic parameters are retrieved by the Gauss-Newton method. Application of the proposed method to model and real data demonstrates its ability to achieve high-precision anisotropic parameter inversion without being constrained by well logging data, providing a basis for acquiring micro-fracture information in fractured reservoirs.
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