Patent ID: 6760667
Filing Date: 2004-07-06
Classification: G01V

Abstract:
A method for generating at least one of P-S or Sâ€”S seismic data from Pâ€”P AVO data in Pâ€”P travel time for a geographic area, comprising:obtaining a plurality of amplitude and angle of incidence pairs of Pâ€”P AVO data; inverting the plurality of amplitude and angle of incidence pairs of Pâ€”P AVO data; and producing estimates of rock property contrasts from the inverted plurality of amplitude and angle of incidence pairs of Pâ€”P AVO data, the rock property contrasts including at least one of &Dgr;Vp/Vp, &Dgr;Vs/Vs and &Dgr;&rgr;/&rgr;, wherein inverting the plurality of amplitude and angle of incidence pairs of Pâ€”P AVO data includes using at least one of a linear Pâ€”P AVO equation or a non-linear Pâ€”P AVO equation and wherein, for a geographic area in which a cap rock and reservoir are each isotropic and the data type to be generated comprises P-S data, the linear Pâ€”P AVO equation for describing the amplitude variation with offset and hence angle of incidence (&thgr;), due to a reflection between the cap rock and reservoir, comprises an equation given by: Amp&it;â€ƒ&it;(Î¸)PS=D0*Sin&it;â€ƒ&it;(Î¸)*(2*Sin&it;â€ƒ&it;(Î¸)2-g2)2*g*g2-Sin&it;â€ƒ&it;(Î¸)2-Sin&it;â€ƒ&it;(Î¸)*Cos&it;â€ƒ&it;(Î¸)g+D1*(2*Sin&it;â€ƒ&it;(Î¸)3g*g2-Sin&it;â€ƒ&it;(Î¸)2-2*Sin&it;â€ƒ&it;(Î¸)*Cos&it;â€ƒ&it;(Î¸)g)where: D0=(Â½)*&Dgr;&rgr;/&rgr;, and D1=(2/g)*&Dgr;Vs/Vs.