WELL VELOCITY
Whilst velocity modelling (primarily for depth conversion) there are situations where modelling top-down is not necessarily sensible, for example below an erosion surface of an unconformity or seabed, therefore modelling base-up may be a better solution.
The following image shows an example of Vo-K optimised for depth (created in Excel)
Left Checkshot data plotted from base upwards. Right upper: Vo-K data selection with solver and standard excel solutions Right center: depth errors from solver solutions. Right lower: Simple image showing that depth below the Top surface is not a good indicator of the velocity i.e. 1m below the Top surface on the left is significantly slower than on the right. Colourfill representing velocity increasing towards the Base.
