Dictionary:Overpressure

{{#category_index:O|overpressure}} The amount by which the formation-fluid pressure exceeds hydrostatic or normal pressure (q.v.). Overpressure, which can have several causes, generally indicates that fluid pathways to the surface were cut off at some time so that the interstitial fluid could not escape to restore equilibrium. The top of overpressure is sometimes abrupt, sometime gradational. Normal pressure may exist below overpressured formations.