Estimation and Application of Project-Wide Coordinate, Clock-drift and Water Velocity Corrections for OBN Datab

Ocean Bottom Node (OBN) seismic surveys have inaccuracies in the node and shot positioning, spatial and temporal water column velocity variations, and potentially errors in the timing of the data (clock drift). Through the inversion of direct arrival (DA) picks it is possible to correct for these issues. It has been seen that source signature effects significantly impact the DA picking and the subsequent derived solutions, particularly for the water velocity ( Scholtz et al. 2025 ). However, it’s possible to compensate for the source directivity based on the picks themselves, with a positive impact on the separation of the inverted terms and a more reliable water velocity solution.

Once a solution for the water column velocities is found, it must be interpolated/extrapolated to all points in the production dataset before it can be corrected for. We use a 3D spatial/temporal scheme to achieve this. Finally, after the velocities are updated throughout, we apply an NMO-based statics solution such that the measured water column velocity is replaced with our desired reference water velocity, resulting in more coherent events and less jitter between shots within receiver gathers.