The Characterization Of Shale Gas Reservoirs Based On Sesmic AVO

Shale gas is an important unconventional energy,many experts in the world regard shale gas reservoir prediction as an important research work.Shale has many characteristics,such as strong anisotropy,complex mineral composition,various porosity and so on.Aimed at Bakken shale,the anisotropic DEM rock physics modeling method is proposed,the predicted results are good.Shale rock physics model is built by integrating isotropic SCA model and the improved Backus average model.A set of rock physical templates are built and can be used to qualitatively interpret the seismic inversion results.The shale may show strong orthorhombic anisotropy if there exists vertical cracks in it Orthorhombic anisotropy rock physics model can be built on the basis of Wu modeling process.There are many possibilities of different lithology parameters combination.As to different combinations,the changing characteristics of the amplitude coefficient related to the incident angle are not the same.The VTI medium and HTI medium reflection coefficient changes with the incidence angle or azimuth,this regulation is the basis of finding oil and gas layer.Through reasonable orthorhombic shale rock physics modeling with cracks,a two layers model can be set up and the reflection coefficient can be calculated,it is possible to prove the effect of mineral content and porosity on the p-wave reflection coefficient associated with azimuth.The orthorhombic anisotropy can be better described on the Ruger formula,it found that the increase of the content of kerogen would influence the explanation of the anisotropic gradient term.