Patent ID: 7974785

Claim:
A method for evaluating fluid pressures in an underground zone by means of well data obtained from at least one well and seismic data comprising at least one seismic cube discretizing said zone into elementary volumes located by their horizontal (x,y) and vertical coordinates in time (t), the method comprising the following stages: a) defining at least one time analysis interval for said zone, b) performing in said analysis interval a pre-stack stratigraphic inversion of said seismic data, using geological a priori information, so as to construct at least one seismic impedance cube, c) determining a lithoseismic facies cube by carrying out a lithoseismic analysis comprising interpretation of said seismic impedance cube in terms of lithoseismic facies from said well data, d) using said well data to determine seismic impedances in said well expressed in time, as well as differential pressures in said well expressed in time, e) determining for each of said lithoseismic facies at least one petro-acoustic relation connecting said seismic impedances in said well to said differential pressures in said well, in said analysis interval, f) determining a differential pressure cube by converting said seismic impedance cube by means of said petro-acoustic relation and said lithoseismic facies cube, g) determining a confining pressure cube from said seismic impedance cube, h) determining said fluid pressures over all of said zone, by calculating the difference between said differential pressures and said confining pressures.