Pressure-actuated valve and method

摘要

A downhole valve 10 opens or closes a bypass (12,13) in response to the pressure of the fluid in the valve. The valve housing body 14 is adapted for fluid communication with a tubular within a well bore. The valve bypass may be repeatedly cycled from open to closed position by selectively raising and lowering the fluid pressure. A replaceable flow restriction 18 in the valve is sized to produce a desired flow-induced pressure drop across the valve to cycle the valve with fluid flow. Differential sealing areas (11c and 15,16) are provided to cycle the valve by varying the static fluid pressure in the valve. According to the method, a flowing fluid pressure drop induced by fluid flow through the valve is used to change the state of the valve, and a subsequent change in hydrostatic fluid pressure or fluid pressure is used to return the valve to its original state.