The supervision of stacking velocity data sets, whether hand or automatic picking, is crucial before entering the stack process itself or any other pre-stack or post-stack processing, such as migration or depth conversion. Apart from the internal geophysical quality control of the velocity picks, the control of the spatial consistency of the data set is an additional useful tool for validating the data. Geostatistics provides a quick and operational way of assessing the spatial quality of the stacking velocity data sets through the computation of a Spatial Quality Index (SQI®)1 attached to each velocity pick: High SQI values highlight data that are not spatially consistent with their neighbours. These are easily localised and submitted to the geophysicist in charge of the supervision for interpretation and possible update of the velocity analysis. The case study illustrated below was conducted within the scope of a joint research project with operators and contractors in order to validate the spatial quality control using geostatistics. The SQI results were validated by the geophysicist after a conclusive blind test and stack control. The spatial quality control of seismic velocity data sets is now operational and has already been run on more than 200 data sets. An equivalent spatial quality control of 4D seismic amplitude cubes is now being developed on the same methodological basis.