USE OF DOWNHOLE ISOLATION VALVE TO SENSE ANNULUS PRESSURE.

摘要

A method of drilling a wellbore includes deploying a drill string into the wellbore through a casing string disposed in the wellbore. The casing string has a pressure responsive element and a hydraulic line (37o) in communication with the element and extending along the casing string. The method further includes: drilling the wellbore into a formation by injecting drilling fluid through the drill string and rotating a drill bit of the drill sting; and while drilling the formation, monitoring (21m) a pressure of the hydraulic line to ensure control of the formation.