Pipe joints or couplings – With means blocking release of holding means – Thread lock
Reexamination Certificate
2001-03-12
2001-11-27
Nicholson, Eric K. (Department: 3627)
Pipe joints or couplings
With means blocking release of holding means
Thread lock
C285S382000, C403S375000, C166S277000, C166S207000, C138S118000
Reexamination Certificate
active
06322109
ABSTRACT:
This invention relates to a tubing connector, and in particular to a connector for use in joining lengths of expandable tubing.
WO-A-93/25800 (Shell Internationale Research), the disclosure of which is incorporated herein by reference, describes a method of completing an uncased section of a borehole in an underground oil-bearing formation. An expandable liner provided with overlapping longitudinal slots is fixed at a predetermined position in the borehole. A tapered expansion mandrel is then moved through the liner and expands the liner to a diameter larger than the mandrel maximum diameter. Ideally, the liner is expanded to such an extent that it contacts the bore wall.
In certain applications it is desirable to provide a relatively long section of borehole with slotted liner. This requires two or more lengths of slotted liner to be joined together at the surface, prior to running into the borehole. Conventionally, the lengths of liner are welded together, however this is a time-consuming and potentially dangerous operation, due to the elevated temperatures created by the welding process. The heat created by the welding operation may also affect the properties of the metal at the liner ends. Achieving consistent weld quality may also be difficult, particularly when the welding operation is to be carried out, for example, in exposed conditions on an offshore facility. Further, if any problems are encountered while running the liner into the borehole, and the liner string must be retrieved, it is not possible to disconnect the welded lengths of tubing and these must be cut apart, and the cut lengths may have to be scrapped.
It is among the objectives of the embodiments of the present invention to provide a tubing connector which will obviate or mitigate at least some of these disadvantages.
According to a first aspect of the present invention there is provided a tubing connector for joining the ends of two lengths of expandable tubing, the connector comprising two expandable tubular portions for mounting on the ends of the lengths of expandable tubing, each portion including a plurality of circumferentially spaced couplings for engaging corresponding couplings on the other portion, the engaging parts of the couplings being located on parts of the tubular portions which are substantially undeformed following expansion of the tubular portions.
For use with expandable tubing featuring overlapping longitudinal slots, the tubular portions may include corresponding overlapping longitudinal slots arranged such that the connected tubular portions exhibit a similar pattern of slots to the tubing, with the couplings located on the “nodes” between the ends of axially aligned slots.
To provide the connection with the necessary strength it will often be necessary for the thickness of material at the connected couplings, that is where the corresponding couplings overlap or meet, to be greater than that of the remainder of the tubular portions and the expandable tubing itself, such that the couplings may be upset from the inner or outer tubing surface.
Preferably, the couplings may be disconnected, to allow disconnection of the tubing lengths, if desired.
Preferably also, the cooperating or engaging parts of the coupling may define, for example, cooperating tongues and slots or pins and bores, the couplings may be threaded, and the couplings may define teeth or undercuts. The couplings will generally be provided in male and female form, that is one coupling is axially received within the other. The couplings may additionally be secured to one another by any suitable means or combination of means, including adhesive, radial screws or pins.
The couplings of one embodiment are in male and female form and define corresponding threads, the outer female coupling including a dog which is biassed towards a position engaging the corresponding male coupling. Preferably, the dog is initially held in a retracted position and may be released, once the couplings are in the desired relative positions, to engage the male coupling. Conveniently, the dog is in the form of a sprung pin.
Preferably also, the longitudinal extent of each coupling is restricted to parts of the tubular portions which are substantially undeformed following expansion of the tubular portions. In other embodiments the couplings may extend over parts of the tubular portions which are subject to deformation.
The connector may be provided in combination with lengths of expandable tubing.
The tubular members may include radially extending handling shoulders, to facilitate handling of the respective tubing lengths.
The tubular members may be integral with the respective tubing lengths, or may be formed separately and welded or otherwise connected to the tubing length. In the former arrangement the ends of the tubing lengths are machined or otherwise shaped to form the tubular members. In the latter arrangement the tubular members may be at least partially formed and then welded or otherwise fixed to the tubing lengths; in a preferred embodiment the longitudinal slots in the tubing lengths and the tubular portions are formed once the tubular portions have been welded to the respective tubing lengths.
According to a further aspect of the present invention there is provided a tubing connector for joining the ends of two lengths of expandable tubing, the connector including expandable tubular portions for mounting on the lengths of expandable tubing and each expandable tubular portion having a coupling part for joining with a coupling part of another tubular portion, a first coupling part being of larger diameter to receive a second coupling part, whereby the expanded connector defines an upset where said first and second coupling parts overlap.
The upset may be external or internal, though it is generally preferred that the upset is external. An external upset may assist in anchoring expanded tubing in a bore by engaging the bore wall or engaging cement into which the connector expands.
The thickness of material, typically metal, present at each upset will generally be equivalent to twice the thickness of the tubing or the expandable tubular portions.
According to a still further aspect of the present invention there is provided an expandable connector for joining the ends of two lengths of expandable tubing, the connector comprising first and second expandable tubular portions for mounting on the ends of the respective lengths of expandable tubing, the first portion including a plurality of circumferentially spaced dogs, each dog being biassed towards an extended position for engaging the second portion, the dogs initially being held in a retracted position and being releasable to move to the extended position to engage the second portion once the portions have been brought together.
According to another aspect of the present invention there is provided a connector comprising first and second threaded parts, the first part including a dog biassed towards the second part, wherein once the parts have been threaded together the dog engages the second part to restrict relative rotation of the parts.
Preferably, the dog is initially held in a retracted position, to permit relative rotation of the parts, and is releasable to engage the second part at an appropriate point. Conveniently, the dog is in the form of a sprung pin. The pin may be located in a bore in the first part and be released from the exterior of the part by, for example, withdrawing a clip engaging the pin and which rests on the outer surface of the first part.
REFERENCES:
patent: 2226804 (1940-12-01), Carroll
patent: 3353599 (1967-11-01), Swift
patent: 4626129 (1986-12-01), Kothmann et al.
patent: 5366012 (1994-11-01), Lohbeck
patent: 5924745 (1999-07-01), Campbell
patent: 5984568 (1999-11-01), Lohbeck
patent: 6012522 (2000-01-01), Donnelly et al.
patent: 6065500 (2000-05-01), Metcalfe
patent: 98/22690 (1998-05-01), None
patent: 98/42947 (1998-10-01), None
Campbell Alasdair
Metcalfe Paul David
Moser, Patterson & Sheridan L.L.P.
Nicholson Eric K.
Weatherford / Lamb, Inc.
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