That pressure due to the weight of a column of liquid ( formation water, drilling mud, etc.) extending from the depth of interest to the liquid level which might or might not be at the surface.
The pressure within a fluid (such as water) at rest, exerted on a given point within the body of the fluid.
the force exerted by a body of fluid at rest. It increases directly with the density and the depth of the fluid and is expressed in pounds per square inch or kilopascals. The hydrostatic pressure of fresh water is 0.433 pounds per square inch per foot of depth (9.792 kilopascals per meter). In drilling, the term refers to the pressure exerted by the drilling fluid in the wellbore. In a water drive field, the term refers to the pressure that may furnish the primary energy for production.