Pre-stack seismic inversion investigation for x4 gas formation in guangan area

X4 formation in Guangan area is severely anisotropicand has complex gas-water relationship.Reservoir prediction and gas-water identification are the major prospecting problems needing urgent solutions.Through pre-stack inversion the P-impedance,S-impedance,and density can be obtained,which will then be used for reservoir prediction and gas/water identification.In this paper on basis of petrophysical analysis and AVO modeling,it is proved Prestack inversion can be used for reservoir prediction and gas/water identification in this area.Part stack data of the near,middle and far offset were used to get the inversion results of P-impedance,Simpedance,and density.And then various elastic parameters were calculated to predict the thickness of the reservoir and the gas-water distribution in the area.The study indicates the pre-stack inversion technology is effective for reservoir prediction and gas-water identi fication for Xujiahe formation.