The process of transforming seismic data from a scale of time (the domain in which they are acquired) to a scale of depth to provide a picture of the structure of the subsurface independent of velocity. Depth conversion, ideally, is an iterative process that begins with proper seismic processing, seismic velocity, analysis and study of well data to refine the conversion. Most geoscientists in the petroleum industry are dealing with the problem that seismic information is usually displayed in some form of a time section, be it a time stack section or a time-migrated section. Drillers, engineers, geologists, geophysicists, and earth scientists in general describe the earth in depth, as in “x” number of feet to target, “x” number of feet of oil column, etc. How do you get easily from time to depth? The answer depends on the desired level of complexity, which is usually dictated by how soon something is needed or how much it will cost. The overall process is called depth conversion, although some prefer to be more rigorous and call it depth migration. The simplest definition of depth conversion is the conversion of some measurable time quantity into some understandable value in depth.