Abstract：The paper analyzed the identified ability of phase spectrum and amplitude spectrum in different phase systems,discussed the sensitivity of phase spectrum and amplitude spectrum to weak amplitude variation and the impact of random interference nn phase spectrum and amplitude spectrum. The advantages and disadvantages of phase spectrum and amplitude spectrum are analyzed by using forward model. The methods using bispectrum to detect fracture are presented:the phase Condansate gas has physical characters between oil and dry gas,which is difficult to distinguish them by well logging data. Using optimization sace principle to calculate the contents of condenoil and condendate gas separately in an tion of reservoir,the ratio nn surface from paper calculated the condigasoil above results. It is proved by production test in 13 layers from f wells that the gas-oil ratio calculated from well logging information can more correctly identiFy condensate gas reservoir.
