Method and system for generating a seismic gather

A system for generating a seismic gather, comprising:

• a computer readable storage medium on which is stored an initial gather of blended seismic signals induced in a common seismic receiver by a plurality of sources that are actuated in actual source groups, wherein the sources belonging to one actual source group, when actuated, cause mutually interfering wavefields in an earth formation which give rise to the blended seismic signals in the common receiver, wherein the sources in each actual source group are positioned relative to one primary source and according to a linear source geometry that is the same for each actual source group, and wherein the plurality of sources in each actual source group is fired according to a pre-selected firing sequence that is the same for each actuation of each actual source group, and wherein successive actual source groups are fired one after another with sufficient time delay between firing of the successive actual source groups to avoid interference in time-frequency domain of a seismic wave field produced in the earth formation by each of the actual source groups with the seismic wave field produced in the earth formation by any other of the actual source groups, and wherein the successive actual source groups are laterally displaced from each other whereby the plurality of sources of all the actual source groups are mapped to a selection of pre-plot source points on a source line consisting of a regular linear grid of discrete pre-plot source points;
• a computer processor operatively coupled to the computer readable storage medium and programmed to:
• create actual shot records from the blended signals;
• create fictive shot records of seismic signals for fictive source groups that each have the same source geometry as the actual source groups, by interpolation of the actual shot records with a selected interpolation operator working on the actual shot records, whereby every pre-plot source point on the source line is uniquely occupied by one primary source out of a set of primary sources of the actual source groups and the fictive source groups taken together, such that every pre-plot source point on the source line has one primary source and every primary source has one pre-plot source point;
• separate single source shot records of single source signals by discrete deconvolution of the actual shot records and the fictive shot records whereby separating signals;
• and
• an output device operatively coupled to the computer processor and configured to output a seismic gather comprising a plurality of the single source shot records for a range of source points.

A method of recording blended seismic signals induced in a common seismic receiver, comprising:

• actuating a plurality of actual sources grouped in actual source groups, wherein the sources belonging to one actual source group, when actuated, cause mutually interfering wavefields in an earth formation which give rise to the blended seismic signals in the common receiver, wherein the sources in each actual source group are positioned relative to one primary source and according to a linear source geometry that is the same for each actual source group, and wherein the plurality of sources in each actual source group is actuated according to a pre-selected firing sequence that is the same for each actuation of each actual source group, and wherein successive actual source groups are fired one after another with sufficient time delay between firing of the successive actual source groups to avoid interference in time-frequency domain of a seismic wave field produced in an earth formation by each of the actual source groups with the seismic wave field produced in the earth formation by any other of the actual source groups, and wherein the successive actual source groups are laterally displaced from each other whereby the plurality of sources of all the actual source groups are mapped to a selection of pre-plot source points on a source line consisting of a regular grid of discrete pre-plot source points;
• and
• recording the blended seismic signals from each of the actual groups by at least one common seismic receiver;
• wherein the blended seismic signals are processable by:
• providing actual shot records from the blended signals;
• creating fictive shot records of seismic signals for fictive source groups that each have the same source geometry as the actual source groups, by interpolation of the actual shot records with a selected interpolation operator working on the actual shot records, whereby every pre-plot source point on the source line is uniquely occupied by one primary source out of a set of primary sources of the actual source groups and the fictive source groups taken together, such that every pre-plot source point on the source line has one primary source and every primary source has one pre-plot source point;
• separating single source shot records of single source signals by discrete deconvolution of the actual shot records and the fictive shot records whereby separating signals;
• and
• outputting a seismic gather comprising a plurality of the single source shot records for a range of source points.