Dictionary:Pore-pressure gradient

1. Changes in formation-fluid pressure divided by the depths over which they are measured; the slope of the interstitial-fluid pressure versus depth curve, the local pressure gradient (q.v.). 2. The average pore-pressure gradient (formation-fluid pressure divided by the depth) is what determines mud weight (q.v.); usually measured in equivalent mud weight (EMW), psi/ft, or Pa/m. See also normal pressure.