Shell Oil Comapny

Kurang Jvalant Mehta

Paul James Hatchell

Andrey Victorovich Bakulin

A method for identifying clock timing discrepancies in at least one clock of interest that is associated with a marine seismic receiver, comprises collecting from at least one marine receiver other than the receiver of interest a first data set corresponding to a selected time period, said first data set being selected to include ocean wave signals; collecting from the receiver of interest a second data set corresponding to the selected time period, said second data set being selected to include ocean wave signals; applying a mathematical prediction technique to the ocean wave signals in the first data set so as to generate a predicted response for a receiver co-located with the receiver of interest; comparing the predicted response to the second data set so as to generate a correlation data set; and using the correlation data set to determine a corrected parameter for the receiver of interest.

Seismic clock timing correction using ocean acoustic waves

A method for identifying clock timing discrepancies in a plurality of clocks that are each associated with a seismic receiver, comprises the steps of collecting from at least a pair of receivers a data set corresponding to a selected time period, cross-correlating the data sets between at least one pair of receivers so as to produce cross-correlated data for positive, zero, and negative time lags, comparing the cross-correlated data for the positive and negative time lags to measure a timing asymmetry about the zero-lag time, and, for a receiver pair for which there is a non-zero timing asymmetry, using the asymmetry to identify a timing discrepancy between the clocks associated with that receiver pair. The each data set can be filtered so as to obtain data in a selected frequency range, which may avoid an active shot frequency. The data may be collected in the absence of active seismic shots.

Method of imaging seismic data recorded using a set of seismic receivers positioned to receive seismic responses from a subsurface formation upon activating a seismic source. The seismic responses are direction-sensitive responses. A virtual signal received by receiver k from the virtual source at the position of receiver m is determined by processing involving cross correlating at least part of the responses of a receiver m with at least part of the responses of a seismic receiver k. Part of direction-sensitive responses or part of the virtual signal that contains a component of the wave field at receiver m traveling in a first direction and part of the direction-sensitive responses or part of the virtual signal that contains a component of the wave field at the receiver k traveling in a second direction may be removed.

Growing community of inventors

Houston, TX, United States of America

Kurang Jvalant Mehta