réservoir en surpression

CONT: Extrapolation of the fluid gradient in the overpressured reservoir back to the surface datum would show a pressure greater than 1 atm [atmosphere].
OBS: In abnormally pressured reservoirs, the continuous pressure-depth relationship is interrupted by a sealing layer, below which the pressure changes. If the pressure below the seal is higher than the normal (or hydrostatic) pressure, the reservoir is termed overpressured.
OBS: In order to maintain underpressure or overpressure, a pressure seal must be present.