Wells – Valves – closures or changeable restrictors – Longitudinally movable operator
Reexamination Certificate
2000-04-28
2001-12-04
Neuder, William (Department: 3672)
Wells
Valves, closures or changeable restrictors
Longitudinally movable operator
C166S183000
Reexamination Certificate
active
06325151
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the tools and methods for producing fluids from within the Earth. More particularly, the present invention relates to a pressure differentially operated production valve.
2. Description of the Prior Art
In the industrial context of petroleum production and earth boring, pressure differentially operated production valves are flow control devices positioned downhole within a petroleum production tube. One purpose for which the valve is used is for isolating a petroleum production zone during the well completion process. After one or more annulus isolation packers are set above or below or both relative to the production zone, the differential valve is opened to permit well fluid flow into the production tube. The valve is opened by elevated fluid pressure within the production or completion tube after the packers are set and the production zone is isolated from the atmospheric surface.
Prior art valves are opened by a pressure value that is the differential between the tubing bore pressure and the well annulus pressure. Consequently, the magnitude of fluid pressure essential for opening the valve is dependent on the annulus pressure in the immediate proximity of the valve. However, because the production zone is isolated from the atmospheric surface head by the packers above the production zone, the production zone pressure is not always known. In isolation, the production zone pressure may be considerably greater or less than the surface head. This unknown in the production zone pressure is translated to an unknown pump pressure required to open the valve.
It is therefor, an object of the present invention to provide a downhole production valve having an operating pressure that is independent of the production zone pressure.
Also an object of the invention is a downhole valve that is operatively responsive to the annulus pressure above a predetermined uphole packer.
SUMMARY OF THE INVENTION
The invention is a well fluid production valve that is positioned downhole in a closed condition below an upper formation packer. Actuation pressure for opening the valve to admit a flow of well fluids from the production zone is a predetermined differential between the well pressure above the packer, usually a function of the well depth, and the operator controlled pressure within attached production tubing. The formation pressure, which may be more or less than the corresponding head pressure, is isolated from the valve actuator and therefore does not contribute to the valve actuating pressure. A fluid pressure conduit is provided that transmits fluid pressure from a well annulus zone above the upper formation packer down past the packer and internally thereof to the valve actuation cylinder.
The well fluid flow ports of the valve are slots or large apertures in a cylindrical mandrel. Concentrically around the mandrel and radially spaced therefrom is an exterior tubing wall. The well fluid flow path is from an annular space between the mandrel and the interior bore of the production tubing below the valve ports.
Within this annular space is a fluid pressure cylinder, preferably disposed above the valve ports. The upper end of this cylinder is in open fluid communication with the well annulus above the packer. The lower end of the cylinder terminates in the proximity of the valve ports. Below the cylinder lower termination, the annular space between the mandrel and the production tube bore enlarges radially. The well valve operator is a sliding sleeve having a fluid pressure sealed fit to the surface of the mandrel and to the lower end of the annular cylinder. The sleeve wall thickness is sufficiently thin to allow adequate flow area between the O.D. surface of the sleeve and the I.D. surface of the tubing bore below the cylinder when the sleeve is axially displaced below the flow ports at an open port position for fluid flow. The valve operator sleeve Is biased to the open port position by a coiled tensile spring wound about the mandrel below the operator sleeve.
Collet fingers extend upwardly from the upper edge of the operator sleeve closely alongside the mandrel O.D. These collet fingers include chocks that bear resiliently against the mandrel O.D. surface. When the operator sleeve is axially aligned along the mandrel to close the flow ports, the collet finger chocks mesh with depressions in the O.D. surface of the mandrel to oppose the displacement bias of the coiled tensile spring.
Holding the collet finger chocks in the mandrel depression is a sear mechanism including the circumferential skirt of an annular piston. The sear piston makes a fluidtight seal with the annular cylinder between the mandrel O.D. and the tubing I.D. The sear piston skirt extends axially from the lower edge of the piston to tightly fill the annular space between the collet fingers and the tubing I.D. Notwithstanding the coiled spring bias, the collet fingers cannot flex sufficiently to lift the chocks out of the mandrel depressions. Hence, the operator sleeve is locked at the closed flow port position.
The operator sleeve closes the flow port by an outer O-ring seal between the O.D. of the sleeve and the I.D. of the cylinder above the flow port and an inner O-ring seal between the I.D. of the sleeve and the O.D. of the mandrel below the flow port. Consequently, although the flow port is closed between the inner bore of the mandrel and the fluid flow annulus between the mandrel O.D. and the inner bore of the production tube, a fluid pressure conduit remains between the inner bore of the mandrel and a bottom face of the annular piston. This fluid conduit is routed through the flow ports and longitudinal slots between the collet fingers. Accordingly, opposing faces of the piston are subjected to different pressure sources: the upper face bearing the above packer annulus pressure and the lower face bearing the mandrel internal bore pressure.
The internal bore of the mandrel is open with the upper production tube bore and is served by service pumps at the well surface. Hence, the internal bore of the mandrel is a controlled variable whereas the upper well annulus is a substantially known constant.
The sear piston is secured at the flow port closed position by a shear pin or screw fastener. When opening is desired, pressure within the internal bore of the mandrel is increased to generate sufficient pressure differential with the uphole annulus pressure to shear the piston fastener. When the shear fastener fails due to the pressure induced force differential, the annular piston slides upwardly to remove the piston skirt from the collet blocking position. The coil spring bias is constantly present and when the collet blocking skirt is removed, the standing bias on the operator sleeve pulls the sleeve collet chocks out of the depression and the sleeve away from the flow port blocking position whereupon the valve is opened.
REFERENCES:
patent: 3079996 (1963-03-01), Tamplen
patent: 4657083 (1987-04-01), Ringgenberg
patent: 4834176 (1989-05-01), Renfroe, Jr.
patent: 6112816 (2000-09-01), Orzechowski et al.
patent: 6220359 (2001-04-01), Poulard
patent: 6230811 (2001-05-01), Ringgenberg et al.
Turley Rocky A.
Vincent Ray
Baker Hughes Incorporated
Madan Mossman & Sriram P.C.
Neuder William
LandOfFree
Packer annulus differential pressure valve does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Packer annulus differential pressure valve, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Packer annulus differential pressure valve will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2576404