Inversion of a vertical seismic profile by minimization of an entropy like function.

摘要

The invention relates to a method of inverting seismic traces Sk by determining the series R = {ri} representative of the seismic reflection coefficients from geological strata. The method consists: in determining an approximate solution R DEG by minimizing an entropy type function H(R) = SIGMA f(ri) under constraints related to the upgoing wavefield Uk and the downgoing wavefield Dk; in determining a correction value DELTA R by minimizing a linear function J( DELTA R) under linear constraints related to the noise in the traces and to the time-depth curve extracted from the traces; and in calculating R = R DEG + DELTA R representative of the reflection coefficients. In a variant, it is possible to guide the selection of the approximate solution R DEG by taking account of information contained in one or more logs, and in determining DELTA R so that the series R satisfies the stacking velocities which result from surface seismic processing.