A Simple Simultaneous Estimation of Water Static, Non-linear Clock Drift and Node Depth Error for Deep Water OBN

Ocean bottom node (OBN) acquisition presents some interesting challenges and opportunities for data processing. Among these are the statics caused by water velocity variations over time, node depth error, non-linear clock drift, and water height variation due to tides. Each one is a tractable problem in the absence of the three other effects; however, when all three are acting simultaneously the interaction makes it difficult to solve them.

We explain the problems associated with determining these effects due to their interactions, and propose a simple and efficient method to simultaneously estimate the effects of all. We describe the simplifying approximations that reduce the problem to source and receiver consistent static corrections. We introduce a dynamic binning procedure used to correct the asymmetry of OBN ray paths. Using a deep water OBN dataset from offshore Nigeria, we present the results of the procedure and show static corrections due to water velocity variation, non-linear clock drift, node depth error and tidal variations. We show the final images of the down-going wave mirror-migration, verifying that the application of the static corrections improve the image.