Patent ID: 6725937
Filing Date: 2004-04-27
Classification: E21B

Abstract:
Downhole apparatus comprising:a body for mounting on a tubular string and defining a bore; a fluid pressure actuated valve member movable relative to the body; a normally closed flow port in one of the body and the valve member, with the valve member in a first position relative to the body the port being closed, and with the valve member in a second position the port being open to permit fluid communication therethrough between the body bore and the exterior of the body, the valve member being biassed towards the first position; and a fluid pressure actuated latch arrangement for releasably retaining the valve member in the first position, the latch arrangement being releasable on application of a predetermined cracking pressure thereto, to allow the unlatched valve member to move to the second position in response to a valve opening pressure lower than said cracking pressure, and the latch arrangement being resettable to relatch the valve member on return of the valve member to the first position.