Improved method for estimating the position of acoustic reflectors present in a medium, by interpreting the differences between the real and the modeled acoustic wave travel times in this medium.

摘要

A method wherein seismic traces are gathered by means of an acoustic wave transmitting source (S) and a plurality of receptors (R) moving on the surface of the medium; actual observed travel times (tobs) corresponding to reflections of various reflectors in the medium are determined; a parameterized macromodel showing the depth z &cir& _ of the reflectors (i) and the velocity V of the layers of the medium according to the horizontal co-ordinate x &cir& _ is defined; modelized source/receptor travel times (tmod) are determined by a technique for plotting rays from common reflection points (CRPs) on the macromodel reflectors; all the deviations DELTA = tobs - tmod obtained for all macromodel rays from the CRP in question are converted into distance corrections DELTA H along a line (24) passing through said CRP; and the macromodel CRP is moved over distance DELTA H along said predetermined line to provide a corrected CRP position.