Shot Point Dithering Techniques for Marine Seismic Surveys

A tangible computer-readable medium having instructions stored therein that, when executed by a computing device, cause the computing device to perform a method for generating dither values corresponding to source activations to be performed during a marine seismic survey, the method comprising:

• accessing a set of nominal shot points corresponding to a set of sources to be used during a portion of the survey;
• and
• determining a set of dither values, each dither value in the set specifying a difference between one of the nominal shot points and an actual shot point to be produced by the set of sources during the survey;
• wherein determining the set of dither values comprises satisfying one or more constraints chosen from the group consisting of:
• an absolute dither difference constraint, a non-duplication constraint, and a standard deviation constraint;
• and
• wherein each of the one or more constraints is based on differences between dither values corresponding to consecutive ones of the nominal shot points, wherein each such difference comprises a dither difference, such that:
• satisfying the absolute dither difference constraint comprises ensuring that each dither difference corresponding to the set of dither values is greater than a threshold dither difference;
• satisfying the non-duplication constraint comprises ensuring that, for a given set of discrete ranges of dither difference values, at most a threshold number of dither differences corresponding to the set of dither values falls within any one of the ranges;
• and
• satisfying the standard deviation constraint comprises ensuring that the standard deviation of dither differences corresponding to the set of dither values is greater than a threshold standard deviation.

A method for performing a marine seismic survey, comprising:

• activating one or more sources at a plurality of actual shot points, wherein each of the actual shot points differs from a corresponding nominal shot point by a dither value;
• wherein differences between dither values corresponding to consecutive ones of the nominal shot points constitute dither differences;
• and
• wherein a set of dither values corresponding to a portion of the survey satisfies one or more constraints chosen from the group consisting of:
• an absolute dither difference constraint, a non-duplication constraint, and a standard deviation constraint;
• such that:
• satisfying the absolute dither difference constraint comprises ensuring that each dither difference corresponding to the set of dither values is greater than a threshold dither difference;
• satisfying the non-duplication constraint comprises ensuring that, for a given set of discrete ranges of dither difference values, at most a threshold number of dither differences corresponding to the set of dither values falls within any one of the ranges;
• and
• satisfying the standard deviation constraint comprises ensuring that the standard deviation of dither differences corresponding to the set of dither values is greater than a threshold standard deviation.

A non-transitory computer-readable medium having instructions stored therein that, when executed by a computing device on a marine seismic survey vessel, cause equipment associated with the vessel to perform a marine seismic survey, the survey comprising:

• activating one or more sources at a plurality of actual shot points, wherein each of the actual shot points differs from a corresponding nominal shot point by a dither value;
• wherein differences between dither values corresponding to consecutive ones of the nominal shot points constitute dither differences;
• and
• wherein a set of dither values corresponding to a portion of the survey satisfies one or more constraints chosen from the group consisting of:
• an absolute dither difference constraint, a non-duplication constraint, and a standard deviation constraint;
• such that:
• satisfying the absolute dither difference constraint comprises ensuring that each dither difference corresponding to the set of dither values is greater than a threshold dither difference;
• satisfying the non-duplication constraint comprises ensuring that, for a given set of discrete ranges of dither difference values, at most a threshold number of dither differences corresponding to the set of dither values falls within any one of the ranges;
• and
• satisfying the standard deviation constraint comprises ensuring that the standard deviation of dither differences corresponding to the set of dither values is greater than a threshold standard deviation.