Water Velocity Correction | SLB

Water Velocity Correction

Technique that accounts for changes in water temperature and salinity

WesternGeco texture hero

Changes in water temperature and salinity alter the velocity of the seismic signal traveling through the water layer and, hence, the recorded travel times.

Water velocity decomposition (WVD), our primary approach to water velocity correction, is a dynamic correction that accounts for changes in sea conditions over time. Estimates of water velocity, zero-offset time, and water-bottom dips are decomposed from water-bottom reflection times and used to calculate the shifts (delta-t) that are applied to the data. The variable-velocity water layer is treated as a water layer with a known velocity function.

Reduces turnaround time with onboard processing

WVD is a proven robust solution to the challenge of water velocity corrections. Improvements to the algorithms and workflows have reduced the overall turnaround time, enabling use of the technique on the acquisition vessel as part of an accelerated onboard deliverable.

The algorithm can handle datasets with multiple datums and differing source and receiver acquisition depths to accommodate contemporary broadband seismic acquisition techniques.

Amplitude map QC before WVC (left) and after WVC (right) at the water bottom showing the loss of energy due to water velocity variations.

Amplitude map QC before water velocity correction Amplitude map QC after water velocity correction