Patent ID: 6585048
Filing Date: 2003-07-01
Classification: E21B

Abstract:
A flow valve for use in a wellbore system, comprising at least one borehole formed in the earth formation, the borehole being provided with:(a) a valve body having a passage therein for fluid flow from an upstream side of the valve to a downstream side of the valve; (b) a closure member mounted in said valve body passage, said closure member having an open position and a closed position; (c) a spring biasing said closure member to its closed position against a force exerted by a fluid flow on the upstream side of the valve, whereby said closure member is moved to its open position by the application of a reduced pressure in the borehole on the downstream side of the valve, the force exerted by the fluid flow thereafter being sufficient to overcome the force exerted by said spring and maintain the closure member in its open position.