Patent ID: 11899151
Assignee: PGS GEOPHYSICAL AS
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 34:
35. A method of performing 4D seismic surveying, comprising:
accessing first seismic data corresponding to a first seismic survey over a location, wherein the first seismic survey was performed using a first seismic source type and not a second seismic source type;
subsequent to the first seismic survey, performing a second seismic survey over the location to produce second seismic data, wherein the second seismic survey is performed using both the first seismic source type and the second seismic source type;
subsequent to the second seismic survey, performing a third seismic survey over the location to produce third seismic data, wherein the third seismic survey is performed using the second seismic source type and not the first seismic source type;
determining, based on the second seismic data, source difference data indicating differences attributable to source types and not to changes in geological structures associated with the location; and
isolating changes in the geological structures that occurred between a time of the first seismic survey and a time of the third seismic survey, wherein the isolating comprises modifying, based on the source difference data, one of the first seismic data or the third seismic data;
wherein the second seismic survey comprises a 4D seismic survey relative to at least one of the first seismic survey and the third seismic survey, such that both the second survey and the at least one survey employ seismic sensors spaced apart in an inline direction and in a crossline direction, and such that an elapsed time between the second survey and the at least one survey is sufficiently long to allow detectable changes to occur in the geological structures between a time of the second survey and a time of the at least one survey.