Patent ID: 8949031
Filing Date: 2015-02-03
Classification: G01V

Abstract:
1. A method for obtaining a volumetric image of a geological structure present in subsoil, the method comprising: activating a plurality of seismic sources to generate a plurality of seismic waves; acquiring a plurality of traces by registering with a plurality of seismic sensors and processing in one or more computers seismic waves reflected by the geological structure; creating in the one or more computers a shot gather from the plurality of traces for each activation position of each seismic source; grouping in the one or more computers the seismic sources into a plurality of groups of N seismic sources each, N being a finite, positive integer, the N seismic sources of each group in the plurality of groups having a reciprocal distance such as to be contained in a circumference having a diameter lower than a predefined maximum distance; grouping in the one or more computers the groups of seismic sources into super-groups of N groups each, such that each super-group includes N effecting in the one or more computers N migrations for each super-group to obtain a partial volumetric image for each of the N groups in the super-group, wherein for each migration, a composite N-order shot gather is migrated through a numerical processing based on a seismic source selected from the group, thus obtaining an overall migration of N numerically modelling in the one or more computers a contemporaneous propagation of seismic waves generated by activating the seismic sources of the group to obtain a first wave field in each point of the volumetric image in relation to the positions of the seismic sources and with respect to time, back-propagating in depth the registered reflections in the one or more computers to obtain a second wave field in each point of the volumetric image in relation to the positions of the seismic sources and with respect to time, combining the first wave field and the second wave field in the one or more computers to obtain the partial volumetric image; and combining the partial volumetric images obtained from the migrations of the composite N-order shot gathers in the one or more computers to attain an overall volumetric image of the geological structure.