FAVO Methods Study Based On Mesoscopic Scale Theory

Reservoir prediction has been one of the core of geophysical research.Rock physics and fluid indicating factors study are important content of reservoir prediction.The conventional rock physics theory is based on Gassmann theory,which doesn't consider the effect of fluid mobility on the spread of the wave,therefore,elastic parameters are frequency-independent.Traditional fluid factors don't consider frequency information of seismic data,so,there exits some insufficient for fluid detection.The theory of the mesoscopic scale takes the fluid mobility into account,and consider more parameters,such as,permeability,pore geometry parameters,which can describe more complex porous media.On the other hand,compared with AVO technology,FAVO inversion takes advantages of much more frequency information,and the inverted dispersion factor can predict the fluid to some extend.So the study that how to combine with AVO and FAVO inversion reasonably becomes very meaningful.Therefore,the theory of the mesoscopic and FAVO study are two main research points.Firstly,our study build the mesoscopic scale rock model,such as,White model,Johnson model.Double porosity model and Chapman model.These models build the relationship between the elastic parameters and frequency and rock parameters under some premises.Secondly,we analysis the frequency-dependent reflection of the porous media in different situations based on the White model.From the results of study,because of the fluid heterogeneous,the frequency-dependent reflection appear different characteristics in different situations,which provides important theoretical basis for reservoir analysis.Although FAVO inversion can predict fluid to some extent,the results are effected by the accuracy of spectral decomposition.Therefore,in this study we try to combine AVO and FAVO results,and build improved fluid detecting factor called PDDF.And the inverted results of real data demonstrate that the improved factor is available and is immune to accuracy of spectral decomposition to some extent.