Pressure gradient

A scale of pressure differences in which there is a uniform variation of pressure from point to point. For example, the pressure gradient of a column of water is about 0.433 lb/sq in./ft (9.794 kP/m) of vertical elevation. The normal pressure gradient in a formation is equivalent to the pressure exerted at any given depth by a column of 10% salt water extending from that depth to the surface (0.465 lb/sq in./ft or 10.518 kP/m).