Wells – Processes – Operating valve – closure – or changeable restrictor in a well
Reexamination Certificate
2000-06-12
2003-07-22
Bagnell, David (Department: 3672)
Wells
Processes
Operating valve, closure, or changeable restrictor in a well
C166S386000, C166S321000, C166S331000
Reexamination Certificate
active
06595296
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a hydraulic control assembly. In particular, but not exclusively, the present invention relates to a hydraulic control assembly for controlling the operation of one or more downhole tools such as, for example, a circulation valve, a bore isolation unit, a gun system and/or any desired valve assembly.
BACKGROUND OF THE INVENTION
A variety of tools and valves are used downhole in an oil and/or gas well, which tools may, for example, be operated by annulus pressure, tubing pressure or control lines. In particular, a number of downhole tools are required in a borehole of an oil and/or gas well for drilling the borehole and throughout the production period of the well. Often a number of different tools are disposed within the borehole simultaneously, making individual control and/or operation of the tools complex. Furthermore, it may be difficult to ensure that a selected tool is in an activater or reactivated configuration as required.
Also, most downhole tools have internal mechanisms which cycle the tool, or operate them in a particular fashion. These mechanisms take the tool function in a unique and limited fashion. Furthermore, the tools become complex and cumbersome, with built-in weaknesses created by compromises between operating conditions, tool function and size.
It is amongst the objects of the present invention to obviate or mitigate at least one of the foregoing problems.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, there is provided a hydraulic control assembly for controlling the operation of a downhole tool, the assembly being for disposition in a borehole of a well and comprising:
a tubular member having a substantially axially extending chamber, the chamber having a tool control fluid inlet and outlet, the inlet for injecting a tool control fluid into the chamber, and the outlet for fluidly coupling to the downhole tool to control the operation of the tool; and
flow control means for selectively allowing flow of the tool control fluid from the tool control fluid inlet to the tool control fluid outlet.
In this fashion, the present invention may allow a downhole tool coupled to the hydraulic control assembly to be selectively activated deactivated and/or maintained in an activated or deactivated configuration, by selectively allowing flow of the tool control fluid through the chamber of the tubular member.
Conveniently, the tubular member is a casing, lining or well tubing for running-in to the borehole. Preferably, the chamber is formed in a wall of the tubular member. Preferably also, a plurality of axially extending chambers are provided disposed spaced around a circumference of the wall of the tubular member. Alternatively, the chamber may be formed in a housing adapted to be coupled to a length of casing, lining or well tubing. The housing may be coupled to an outer or inner surface of the casing, lining or well tubing.
The flow control means may comprise a movable, substantially cylindrical shuttle valve disposed in the chamber, the shuttle valve comprising at least two radially extending seals for sealing the shuttle valve in the chamber and isolating the tool control fluid outlet from the tool control fluid inlet. The shuttle valve may be axially movable to selectively allow flow of the tool control fluid from the tool control fluid inlet to the tool control fluid outlet.
Conveniently, the flow control means further comprises a gear rod for axially moving the shuttle valve to allow flow of the tool control fluid. The gear rod may comprise ratchet teeth formed on an other surface thereof, and may co-operate with an axially movable mounting cage disposed in the chamber and having a ratchet arm for engaging the teeth of the gear rod. Thus the present invention may allow the shuttle valve to be axially moved to allow flow of control fluid to the downhole tool, by axially moving the gear rod in the mounting cage. Movement of the gear rod is achieved by an interaction between the ratchet teeth of the gear rod and the ratchet arm of the mounting cage.
Preferably, the mounting cage is substantially tubular. The mounting cage may include an upper piston disposed in a cylinder. Preferably, the flow control means further comprises a first fluid inlet fluidly coupled to the cylinder and a second fluid inlet fluidly coupled to the chamber. Thus by selectively injecting fluid into the cylinder and withdrawing fluid from the second fluid inlet, the cage may be moved axially towards the shuttle valve carrying the gear rod therewith.
The flow control means may further comprise a collect disposed in the chamber, the collet having radially extending ratchet arms for engaging the ratchet teeth of the gear rod. Thus, by injecting fluid via the second fluid inlet, and withdrawing fluid via the first fluid inlet, the cage may be moved axially away from the shuttle valve, with the gear rod retained by the collet. The gear rod may therefore be axially moved towards the shuttle valve in step wise fashion.
According to a second aspect of the present invention, there is provided a hydraulic control assembly for controlling the operation of a downhole tool, the assembly being adapted to be located in a borehole of a well and comprising:
a moveable piston;
a tubular member having a substantially axially extending chamber, the chamber having at least two tool control fluid ports for allowing tool control fluid to flow through the chamber; and
flow control means for selectively allowing flow of tool control fluid through one of said ports to the chamber and from the chamber through the other one of said ports to the tool, to control operation of the tool, the flow control means being selectively activated, to allow tool control fluid flow to the tool, by the moveable piston.
Advantageously, this provides a hydraulic control assembly wherein a moveable piston may be moved to cause a flow control means to allow flow of tool control fluid to a downhole tool couple to the hydraulic control assembly. Preferably, flow of tool control fluid to the chamber occurs simultaneously with flow of tool control fluid from the chamber.
The piston may carry an operating finger for engaging the flow control means, to selectively activate the flow control means to in turn allow tool control fluid flow to the tool. Conveniently, the assembly includes a ratchet assembly for restraining the piston. The ratchet assembly may be a ball race ratchet including a ball race track formed in an outer surface of the piston and a ball adapted to engage in the track. The track may define a number of axially spaced rest positions for the ball, with a number of first rest positions for restraining the piston from further axial movement away from the tubular member, and a number of second rest positions, spaced axially from the first rest positions, to restrain the piston from further axial movement towards the tubular member. The rest positions may be formed in the track to define a continuous track for ball to follow. The first and second rest positions may be aligned around the circumference of the piston, and the track may define axial portions extending between the first and second rest positions, and angled track portions connecting adjacent pairs of first and second rest positions.
In this fashion, when the piston is moved axially towards and away form the tubular member, the piston is rotated by an interaction between the ball and the track. The piston may be moved axially by variation of a fluid pressure applied to the piston. This may be achieved by coupling a control line to the piston, or by varying the pressure internally within the hydraulic control assembly, or externally, in an annular defined between the assembly and a borehole wall. Conveniently, the ball is coupled to a casing or other tubing in which the hydraulic control assembly is located separately.
Preferably, the assembly includes two chambers and corresponding flow control means for controlling the operation of two downhole tools, or for separately controlling
Bagnell David
Gay Jennifer H
Gifford, Krass, Groh Sprinkle, Anderson & Citkowski, P.C.
Quartech Engineering Limited
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