couche à pression anormale

CONT: Lorsque les données sismiques ou autres et le résultat des observations en cours de forage d'un puits indiquent l'existence d'une zone de surpression dans les 100 prochains mètres à forer, le délégué aux opérations peut, par mesure de sécurité, imposer la vitesse de pénétration du trépan à adopter pour la suite des opérations.

CONT: Detecting abnormal-pressure intervals ... As the result of special geological conditions, some intervals have pore pressures that are higher than normal hydrostatic pressures. In this type of formation, clays are subcompacted and contain a larger amount of water than normal at the depth where they are found. This situation is revealed by anomalies in the recordings of properties of shaly intervals.
CONT: An operator shall ensure that the production casing used in a well is equipped and cemented with sufficient cement to ... isolate abnormally-pressured intervals from normally-pressured intervals ...
OBS: overpressure: Subsurface pressure that is abnormally high, exceeding the hydrostatic pressure at a given depth.