Late subsurface secondary porosity in a Jurassic grainstone reservoir, Smackover formation, Mt. Vernon field, southern Arkansas.

Abstract

Mt Vernon is the first well-documented case of late subsurface secondary porosity production in a carbonate reservoir. Porosity enhancement was accomplished late in the diagenetic history of the Mt Vernon area, and was closely followed by emplacement of hydrocarbons. Dissolution may have been caused by subsurface fluids charged with CO2 or H2S, or both, gases commonly generated together with hydrocarbons. If this mechanism is valid, the development of subsurface solution porosity in carbonate reservoirs may directly be related to hydrocarbon generation, and should be a common phenomenon in the deeper parts of carbonate hydrocarbon provinces.-J.M.H.