Fremgangsmåte for å opprette en stratigrafisk modell av undergrunnen ut fra en akustisk impedansprofil og en seismisk profil

摘要

A method of establishing a stratigraphic model of the subsurface from an acoustic impedance profile Ao = {ao(n),n=1,N} corresponding to a series of reflection coefficients Ro = {ro(n),n=1,N}, where n is an index relating to the depth sampled in time t, and from a seismic section comprising a plurality of seismic traces Ti(t),i=0,I recorded in response to the emission of a seismic wave of signature W(t), the method comprising the following steps: successively determining each series of coefficients Ri = {ri(n),n=1,N} by minimizing a cross-entropy function H(Ri/ @i) between firstly a series @i obtained from the series Ri-1 and a set of one or more seismic traces {Ti-j,Ti+j}, and secondly the looked-for series Ri, said minimization being performed under pre-established constraints; and determining the acoustic impedance profiles Ai = {ai(n)} corresponding to the series Ri.