Modeling the effects of fracture infill on frequency-dependent anisotropy and AVO response of a fractured porous layer

• 作者: Yan-Xiao He Xin-Long Li Gen-Yang Tang Chun-Hui Dong Mo Chen Shang-Xu Wang
• 来源期刊: 石油科学（英文版）
• 年，卷（期）: 2021,（3）
• 所属期刊栏目: PETROLEUM GEOLOGY & GEOPHYSICS
• 页码范围: 758-772
• 页数: 15页
• 语种: 英文

摘要

In a fractured porous hydrocarbon reservoir,wave velocities and reflections depend on frequency and incident angle.A proper description of the frequency dependence of amplitude variations with offset(AVO)signatures should allow effects of fracture infills and attenuation and dispersion of fractured media.The novelty of this study lies in the introduction of an improved approach for the investigation of incident-angle and frequency variations-associated reflection responses.The improved AVO modeling method,using a frequency-domain propagator matrix method,is feasible to accurately consider velocity dispersion predicted from frequency-dependent elasticities from a rock physics modeling.And hence,the method is suitable for use in the case of an anisotropic medium with aligned fractures.Additionally,the proposed modeling approach allows the com-bined contributions of layer thickness,interbedded structure,impedance contrast and interferences to frequency-dependent reflection coefficients and,hence,yielding seismograms of a layered model with a dispersive and attenuative reservoir.Our numerical results show bulk modulus of fracture fluid significantly affects anisotropic attenuation,hence causing frequency-dependent reflection abnormalities.These implications indicate the study of amplitude versus angle and frequency(AVAF)variations provides insights for better interpretation of reflection anomalies and hydrocarbon identification in a layered reservoir with vertical transverse isotropy(VTI)dispersive media.