This topic outlines the process of integration when working with velocity data. It discusses the types of velocities used in seismic processing, defines their application, identifies the different velocity curves versus time, and describes how to use Dix’s equation to calculate interval velocities. NMO correction and the application to seismic signals is explained. The relationship between velocity and the quantity of sand or shale in stratigraphic layers is addressed as well as the effects of lithology on velocity. The differences between a VSP and a checkshot survey, and a number of ways we use sonic logs and associated data in exploration processes are discussed. It provides details on the three basic factors that we must consider when using a sonic log, lists several tests to ensure the quality of the velocity data, and explains the various sources of statistical error that limit the use of velocities. The topic outlines how seismically derived velocities can be used with sparse well control, identifies two methods that can be used when exploration objectives require a reliable depth conversion algorithm, and explains how interval stacking velocity maps are used to extend values obtained from area wells.