Method for verifying the location of an array of sensors

Claim 1

A method for defining the real locations of the members of an array of detectors, comprising: a) depositing the detectors at nominal locations, D i , the detectors being in communication with a seismic signal processing system; b) causing an acoustic source to sequentially visit each of a plurality of source stations occupying known geodetic locations S j , and to launch an acoustic wavefield therefrom; c) determining a set of nominal ranges, R n i ,j between every known source location, S j , and every nominal detector location, D i ; d) measuring, with said signal processing system, detector-signal travel times representative of the minimum wavefield travel times between every known source station and every nominal detector location to define a set of pick times, P i ,j corresponding to said set of nominal ranges R n i ,j ; e) with the aid of the signal processing system, fitting a global polynomial regression curve of the R n i ,j on the P i ,j ; f) for every pick time P i ,j, selecting a detector specific velocity trend from said polynomial regression curve to define a set of detector-specific computed ranges, R c i ,j ; g) for every pick time P j ,i, selecting a source-specific velocity trend from said polynomial regression curve to define a set of source-specific computed ranges R c j ,i. h) using the sets of computed ranges, multi-laterating the detectors to a new re-positioned detector location; i) substituting the computed ranges from step h) for the nominal ranges in step c), iteratively executing steps d) through h) until the difference between a new repositioned detector location and a previously-defined detector location converges to a predefined limit.

Claim 2

A method for defining the real locations of the members of an array of detectors, comprising: a) depositing the detectors at nominal locations, D i , the detectors being in communication with a seismic signal processing system; b) causing an acoustic source to sequentially visit each of a plurality of source stations occupying known geodetic locations S j , and to launch an acoustic wavefield therefrom; c) determining a set of nominal ranges, R n i ,j between every known source location, S j , and every nominal detector location, D i ; d) measuring, with said signal processing system, detector-signal travel times representative of the minimum wavefield travel times between every known source station and every nominal detector location to define a set of pick times, P i ,j corresponding to said set of nominal ranges R n i ,j ; e) with the aid of the signal processing system, fitting a global polynomial regression curve of the R n i ,j on the P i ,j ; f) for every pick time P i ,j, selecting a detector specific velocity trend from said polynomial regression curve to define a set of detector-specific computed ranges, R c i ,j ; g) for every pick time P j ,i, selecting a source-specific velocity trend from said polynomial regression curve to define a set of source-specific computed ranges R c j ,i. h) using the sets of computed ranges, multi-laterating the detectors to a new re-positioned detector location; i) substituting the computed ranges from step h) for the nominal ranges in step c), iteratively executing steps d) through h) until the difference between a new repositioned detector location and a previously-defined detector location converges to a predefined limit.

Claim 9

A method for estimating the actual locations of the members of an array of detectors beneath a body of water, comprising: a) depositing the detectors at nominal locations, D i , on the bottom of the body of water; b) providing means for transmitting detector signals to a seismic signal processing system; c) causing an acoustic source near the surface of the water to sequentially visit each of a plurality of source stations at known geodetic locations S j , and to launch an acoustic wavefield therefrom; d) by coordinate inversion, determining a set of nominal ranges, R n i ,j between every known source location S j , and every nominal detector location, D i ; e) measuring, with said signal processing system, detector-signal travel times representative of the minimum wavefield travel times between every known source station and every nominal detector location to define a set of pick times, P i ,j corresponding to said set of nominal ranges R n i ,j ; f) with the aid of the signal processing system, fitting a high-order global polynomial regression curve of the R n i ,j on the P i ,j ; g) for every pick time P i ,j, selecting a detector specific velocity trend from the aforesaid polynomial regression curve to define a set of detector-specific computed ranges R c i ,j ; h) for every pick time P j ,i, selecting a source-specific velocity trend from said polynomial regression curve to define a set of source-specific computed ranges R c j ,i i) using the sets of computed ranges, multi-laterating the respective detectors to new re-positioned detector locations; j) substituting the computed ranges from step h) for the nominal ranges in step d), iteratively executing steps e) through i) until the difference between a new repositioned detector location and a previously-defined detector location converges to a predefined limit.

Claim 10

A method for estimating the actual locations of the members of an array of detectors beneath a body of water, comprising: a) depositing the detectors at nominal locations, D i , on the bottom of the body of water; b) providing means for transmitting detector signals to a seismic signal processing system; c) causing an acoustic source near the surface of the water to sequentially visit each of a plurality of source stations at known geodetic locations S j , and to launch an acoustic wavefield therefrom; d) by coordinate inversion, determining a set of nominal ranges, R n i ,j between every known source location S j , and every nominal detector location, D i ; e) measuring, with said signal processing system, detector-signal travel times representative of the minimum wavefield travel times between every known source station and every nominal detector location to define a set of pick times, P i ,j corresponding to said set of nominal ranges R n i ,j ; f) with the aid of the signal processing system, fitting a high-order global polynomial regression curve of the R n i ,j on the P i ,j ; g) for every pick time P i ,j, selecting a detector specific velocity trend from the aforesaid polynomial regression curve to define a set of detector-specific computed ranges R c i ,j ; h) for every pick time P j ,i, selecting a source-specific velocity trend from said polynomial regression curve to define a set of source-specific computed ranges R c j ,i i) using the sets of computed ranges, multi-laterating the respective detectors to new re-positioned detector locations; j) substituting the computed ranges from step h) for the nominal ranges in step d), iteratively executing steps e) through i) until the difference between a new repositioned detector location and a previously-defined detector location converges to a predefined limit.