Forward Modeling Simulation Of Seismic Response For Layered Fractures

Fractures are parts of effective storage space of oil and gas in the reservoir,and they are also the main migration channels.With the continuous development of oil and gas exploration,fractured reservoirs have become an important target in oil and gas exploration,and the prediction of fractured reservoirs is difficult.Studying the propagation characteristics of seismic waves in fractured media is conducive to providing theory for predicting fractures,which is therefore of great significance.The current prediction method for fractures in HTI media is relatively mature,and it is difficult to predict the horizontal fractures in VTI media.However,there are some lowlevel layered fractures in the strata.Therefore,it is necessary to study the seismic response characteristics of horizontal fractures,which is the premise for using the seismic data to predict the low-angle layered fractures.This paper mainly establish horizontal fracture medium model based on the Chapman(2003)equivalent medium theory to analyze the dispersion and attenuation properties of seismic waves in VTI media,and frequency dependence of velocity anisotropy is studied based on Thomsen parameters.Then an anisotropic medium model with overlying elastic isotropic media and underlying horizontal fractured media is established.Then based on the exact formula of the interface reflection coefficient of viscoelastic VTI media given by Carcione(1997),the frequency-dependent reflection coefficient of PP wave at the interface of elastic anisotropy and fracture media is calculated,and.its sensitivity to reservoir parameters is analyzed.Next,an inelastic thin interbed media with horizontal fractures is established,and the influence of inelastic properties and tuning effects on the frequency-dependent AVO response is studied by the propagation matrix method.Finally,based on the rock data and logging data of the actual work area,the seismic anisotropy characteristics of the horizontal layed fractures are studied,which forms the anisotropic inversion method based on the rock physics model.The above research on seismic wave propagation characteristics and seismic response of layered fracture media provides an important theoretical basis for prediction of layered fractures and AVO inversion.