METHOD FOR IMPROVED MAPPING OF TIME OR DEPTH STRUCTURE BASEDON TWO-DIMENSIONAL SEISMIC DATA

The invention concerns a method for producing improved maps of time or depth structure based on two-dimensional seismic data, consisting in migrating nonmigrated 2D data at a velocity function V1 to produce an initial 3D map for a given reflector R2. The method is characterised in that it consists in demigrating all the points P1 of the initial map to obtain de-migrated points P2, selecting the points P2 which are located on or in the proximity of acquisition lines L1...Ln, migrating the selected points P2 at a velocity function V1 to obtain migrated points P3, reading the point P4 of the reflector R2 nearest to the point P3, de-migrating each point P4 to obtain a point P5 to which is assigned a horizontal component of the orthogonal slope associated with point P2, migrating the points P5 to obtain an intermediate 3D map and proceeding by iterative method until points P3 points P4 are convergent.