Methods and systems to operate marine sources to avoid air in water effects
AssigneePGS Geophysical AS
InventorsGregg Parkes, Stian Hegna, Francis Drossaert
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Abstract
In order to avoid complicated and unpredictable effects on the wavefields emitted by air guns activated at different times, methods and systems of the current disclosure are directed to computationally designing a sequence for activating subsets of air guns in a time distributed manner that minimizes the effects of air in the water surrounding the source. The sequence may be used with discrete and continuously recorded marine surveys.
Claims32
A method of determining a timing sequence of sub-sources of a marine source comprising:
- determining a cone angle of a cone of emission for air guns of a source;
- and
- determining a time-distributed sequence in which to activate sub-sources of the source based on the cone angle and location of a volume of air in the body of water to be generated by the sub-sources, the time-distributed sequence to prevent air generated by any previously activated sub-source from contaminating a source wavefield to be generated by a next to be activated sub-source of the sequence.
A system for performing seismic surveys, the system comprising:
- a computer system comprising:
- one or more processors;
- one or more data-storage devices;
- and
- a routine stored in one or more of data-storage devices and executed by the one or more processors, the routine preforms the operations of
- determining a cone angle of a cone of emission for air guns of a source;
- and
- determining a time-distributed sequence in which to activate sub-sources of the source based on the cone angle and location of a volume of air in the body of water to be generated by the sub-sources, the time-distributed sequence to prevent air generated by any previously activated sub-source from contaminating a source wavefield to be generated by a next to be activated sub-source of the sequence.
A physical computer-readable medium having machine-readable instructions encoded thereon for enabling one or more processors of a computer system to perform the operations of
- determining a cone angle of a cone of emission for air guns of a source;
- and
- determining a time-distributed sequence in which to activate sub-sources of the source based on the cone angle and location of a volume of air in the body of water to be generated by the sub-sources, the time-distributed sequence to prevent air generated by any previously activated sub-source from contaminating a source wavefield to be generated by a next to be activated sub-source of the sequence.
A method of collecting seismic data in a marine survey comprising:
- determining a cone angle of a cone of emission for air guns of a source;
- adding a first sub-source to a time-distributed sequence of sub-sources, the first sub-source obtained from a list of sub-sources that partition the source;
- determining a time-distributed sequence in which to activate sub-sources of the source based on the cone angle;
- activating the sub-sources of the source according to the time-distributed sequence;
- and
- recording a wavefield emitted from the subterranean formation.
Dependencies are inferred from the claim text.