Control valve assembly

摘要

In a system for optimizing natural gas production in response to real-time variations in wellbore parameters, a PLC or other wellsite intelligence technology is used to monitor liquid and gas production from the wellbore under friction-loaded conditions. Using baseline production data obtained during production tests, the PLC determines and initiates the appropriate operating mode for the wellbore to optimize a selected production criterion to suit measured wellbore parameters. The operating mode either a continuous clean-out mode, in which gas is continuously injected into the wellbore to control liquid loading, or an intermittent clean-out, in which liquid loading is regulated by intermittent gas injection. In preferred embodiments, the system uses bladder-type control valves having upstream and downstream solenoids, to control production tubing flow rate within a range between upper and lower set points.

主权项

1. A non-venting control valve assembly for installation in a flow line carrying a fluid under pressure, said control valve assembly comprising:
(a) a bladder-type valve having: a valve core; a generally cylindrical bladder having a bladder wall, said bladder surrounding the valve core; a fluid inlet; a fluid outlet; and a pressure port whereby the bladder can be exposed to external pressure; (b) a pressure source in fluid communication with the pressure port; (c) an upstream bypass line connecting the fluid inlet and the pressure source; (d) an upstream solenoid operable to regulate fluid flow through the upstream bypass line; (e) a downstream bypass line connecting the fluid outlet and the pressure source; and (f) a downstream solenoid operable to regulate fluid flow through the downstream bypass line;wherein:
(g) the valve core comprises a pair of frustoconical valve core sections, each having a perforated conical sidewall, a solid end wall, and an opposing open end, with the solid end walls of said sections in adjacent juxtaposition; (h) a positive pressure differential across the bladder wall will urge the bladder against the conical sidewalls of the valve core sections so as to prevent fluid flow through said perforations; and (i) a negative pressure differential across the bladder wall will urge the bladder away from the conical sidewalls of the valve core sections so as to allow fluid flow through said perforations.