You can use two velocity functions: 1) A*Vseis (A = constant rescaling factor, Vseis = seismic interval velocity map)to best calibrate your seismic velocities to the well velocities. 2) A*Vseis+B (A = constant rescaling factor, B = constant shifting factor, Vseis = seismic interval velocity map), meaning that a calibration and shifting of your seismic velocity. To input your seismic velocity to UDOMORE Depth, you need to 1) compute seismic layer velocity in Petrel ; 2) input seismic velocity , and  A,  B parameters to the section A Vseis + B  in UDOMORE Depth . As a result, UDOMORE Depth will optimize your velocity model.