摘要
Rock physical model is an important basis of petrophysical research and S-wave velocity estimation.Based on Xu-White sand-clay mixed model,by using core testing data,P-wave and density log,clay content and porosity measurement,we calculated bulk and shear modulus of dry rock;then,the effective elastic modulus in different fluids with different saturation was calculated;finally,the P-wave velocity and S-wave velocity were computed.By comparison with actual density and P-wave data,we constantly modified parameters and carried out iterative computation.By this means,the S-wave velocity can be obtained.Through S-wave velocity estimation by using rock physical model,the problem of missing S-wave data in conventional logging data of Fangheting structure in Pinghu Gasfield was solved,which provided reliable basic data for AVP forward modeling and pre-stack AVO/AVA simultaneous inversion.