Sand and mud interstratification CO2 geological storages time-lapse seismic the Forward Modeling during without Shear Wave Velocity Well Logging

It is of the invention without Shear Wave Velocity Well Logging when sand and mud interstratification CO 2 Geological storage time-lapse seismic the Forward Modeling includes：Gathered data；Multi-layer technology data；Sandstone mineral composition curve is calculated using well-log information, CO is demarcated 2 P- and S-wave velocity after injection under pressure condition, predicts shear wave velocity；Carry out the P- and S-wave velocity curve after fluid-mixing replaces injection；Retain the well-log information time and depth transfer of thin layer information and calculate reflectance factor using Zoeppritz equations；With Ricker wavelet convolutions, synthetic seismogram is obtained；Using injecting CO 2 Front and rear and injection different phase, the time shift of different dominant frequency are just being drilled artificial synthesized E-selectin and are being subtracted each other, and obtain difference and just drill seismic response.The characteristics of this method is for complicated thin sand-shale interbed, preferably solves CO 2 The fluid-mixing saturation degree replacement problem of different reservoir feature and CO is predicted during the displacement of reservoir oil and geological storage 2 The P- and S-wave velocity of injection stage pressure change.