Pressure range delimited valve with close assist
AssigneeBosley Gas Lift Systems Inc.
InventorsBruce Mitchell, Gordon Bosley
Life of this patent
Estimating the term…
Abstract
A pressure-actuated valve fit to a tubing string for alternately closing to communicate fluids from a wellbore to the tubing string and opening to communicate fluids from a wellbore annulus to the tubing string. The valve is particularly useful for lifting liquids which accumulate in the tubing string when the reservoir has a diminished pressure. In this case, gas is accumulated in the wellbore annulus and when the valve is opened the gas enters the valve and is directed to the tubing string for lifting the liquids. The valve is closed by a spring and has a closing-assist which applies an additional force to the spring to ensure the valve is fully closed.
Claims25
A system for enhancing gas recovery from a wellbore extending to a reservoir having diminished pressure, the wellbore having a tubing string therein, a packer and compressed gas for pressurizing a wellbore annulus, the packer being set, above perforations, between a casing string and the tubing string for forming the wellbore annulus thereabove, liquids accumulating in a bore of the tubing string as wellbore gas is produced therethrough to surface, the system comprising:
- a one-way valve at a bottom of the tubing string for one-way fluid communication from the reservoir to the tubing string;
- and
- a pressure-actuated valve, housed in the bore of the tubing string uphole from the one-way valve and forming a production annulus therebetween in fluid communication with the tubing annulus, the pressure-actuated valve comprising:
- a valve body having a valve bore;
- inlet ports for fluid communication between the wellbore annulus and the valve bore;
- outlet ports in the valve body, spaced downhole from the inlet ports, for fluid communication between the valve bore and the production annulus;
- a plunger axially moveable in the valve bore, uphole from the inlet ports, for alternately
- blocking the inlet ports for preventing gas accumulating in the wellbore annulus from entering the valve body in a closed, production position;
- and
- unblocking the inlet ports for admitting gas from the wellbore annulus to the valve bore and flowing through the outlet ports to the production annulus for lifting accumulated fluids therein to surface in an open, lift position;
- a main spring operatively connected to the plunger for normally biasing the plunger downhole to the production position;
- and
- a pressure-actuated pilot valve system positioned in the valve bore and in continuous pressure communication with the wellbore annulus, wherein
- when the pressure in the wellbore annulus exceeds a preset high pressure, the pilot valve opens to communicate the high pressure to the plunger for overcoming the biasing and moving the plunger from the production position to the open, lift position;
- and
- when the pressure in the wellbore annulus is below a preset low pressure, the pilot valve releases the pressure acting at the plunger, allowing the plunger to be biased from the lift position to the closed, production position.
A pressure-actuated valve for alternately fluidly communicating between a wellbore annulus being pressurized with gas and a tubing annulus, the valve being housed in a tubing string forming the tubing annulus, the tubing string being hung in a wellbore and forming the wellbore annulus above a packer set therein, the valve comprising:
- a valve body having a valve bore;
- inlet ports for fluid communication between the wellbore annulus and the valve bore;
- outlet ports in the valve body, spaced below the inlet ports, for fluid communication between the valve bore and the production annulus;
- a plunger axially moveable in the valve bore, above the inlet ports, for alternately
- blocking the inlet ports for preventing gas accumulating in the wellbore annulus from entering the valve body in a closed, production position;
- and
- unblocking the inlet ports for admitting the gas from the wellbore annulus to the valve bore and flowing through the outlet ports to the production annulus for lifting accumulated fluids therein to surface in an open, lift position;
- a main spring operatively connected to the plunger for normally biasing the plunger to the closed, production position;
- and
- a pressure-actuated pilot valve system positioned in the valve bore and in continuous pressure communication with the wellbore annulus, wherein
- when the pressure in the wellbore annulus exceeds a preset high pressure, the pilot valve opens to communicate the high pressure to the plunger for overcoming the biasing and moving the plunger from the closed, production position to the open, lift position;
- and
- when the pressure in the wellbore annulus is below a preset low pressure, the pilot valve releases the pressure acting at the plunger, allowing the plunger to be biased from the open, lift position to the closed, production position.
A valve-closing assist for a valve, biased to a closed position by a main spring, for ensuring the valve is in a fully closed position, the valve-closing assist comprising:
- a kicker spring operatively connected to the main spring, the kicker spring being
- energized to an energized state when the main spring is overcome and the valve is moved to an open position, the kicker spring being releasably retained in the energized state until the main spring is moved to the closed position;
- and which thereafter
- releases stored energy to the main spring to assist the valve to be in the closed position;
- and releasably retained in the energized state by a locking element acting operatively between a valve body and the kicker spring.
Dependencies are inferred from the claim text.