Method and computer system for determining seismic node position

A non-transitory computer readable medium storing instructions for updating and refining a model X, Y position of an ocean bottom node that when executed cause a computer capable of processing data to perform the steps of:

• a. performing a position estimation routine on the data to obtain a model X, Y position of the node comprising computing a standard deviation of traveltime errors, the traveltime errors defined by differences between a plurality of first arrival times of the data and calculated traveltimes based on the model X, Y position and a measured Z position, the plurality of first arrival times defined by at least one direct arrival and at least one refracted arrival;
• b. performing a position estimation sub-routine on the data to determine a refined model X, Y position of the node, comprising calculating an updated node position and comparing the computed standard deviation of traveltime errors with a computed, new standard deviation of traveltime errors for the updated node position of the node, and if the new standard deviation is lower, then assigning it as a best standard deviation and the updated position as a new position of the node, but if the new standard deviation is greater than the previous best standard deviation then not assigning a new position and the best standard deviation to the node;
• and
• c. selecting the X,Y position of the node as the model node position corresponding to a lowest computed standard deviation.

A computer system comprising a data processor running data processing software on a computer and configured to receive data downloaded from a seismic node, wherein the data processing software is capable of determining X, Y position of the node, where each position along an ocean bottom can be defined using coordinates X and Y, the computer system further configured to perform the steps of:

• a. performing a position estimation routine on the data to obtain a model X, Y position of the node, comprising computing a standard deviation of traveltime errors, the traveltime errors defined by differences between a plurality of first arrival times of the data and calculated traveltimes based on the model X, Y position and a measured Z position, the plurality of first arrival times defined by at least one direct arrival and at least one refracted arrival;
• b. performing a position estimation sub-routine on the data to determine a refined X, Y position of the node, comprising calculating an updated node position and comparing the computed standard deviation of traveltime errors with a computed, new standard deviation of traveltime errors for the updated node position of the node, and if the new standard deviation is lower, then assigning it as a best standard deviation and the updated position as a new position, but if the new standard deviation is greater than a previous best standard deviation then not assigning a new position and best standard deviation;
• and
• c. selecting the X,Y position of the node as the model node position corresponding to a lowest computed standard deviation.