GB2149000A

GB2149000A - Saddle clamp, particularly for tubular well completion

Info

Publication number: GB2149000A
Application number: GB08426031A
Authority: GB
Inventors: Eric Kipperman
Original assignee: LASALLE PETROLEUM SERVICES LIM
Current assignee: LASALLE PETROLEUM SERVICES LIM
Priority date: 1983-10-14
Filing date: 1984-10-15
Publication date: 1985-06-05
Also published as: GB8426031D0; GB8327578D0; GB2149000B

Abstract

The clamp comprises a saddle- shaped member 1 adapted to seat on a tubular drill string with a clamping member 2 hingedly connected thereto and provided at their free edges with releasably fastening means, eg nuts and captive bolts, for releasably fastening the saddle member into clamping engagement with a drill string, preferably in a position spanning the coupling between individual lengths of tubing making up the drill string. Internally the clamp is provided with a recess or recesses 13, 14 which accommodate control lines and/or power cables to secure them against the periphery of the drill string. <IMAGE>

Description

SPECIFICATION Saddle clamp, particularly for tubular well completion This invention relates to a clamp for clamping control lines and power cables to the exterior of a tubular substructure. More particularly the invention relates to a clamp for clamping control lines and power cables to the exterior of a tubular well completion string used in subterranean production operations in spanning and particularly enclosing the couplings joining the individual tubular well completion string lengths together.

In subterranean drilling operations, control lines, injection lines and power cables are often fastened to the external surface of the tubular well completion string that is introduced into the well bore through the tubular well casing. Currently such control lines etc.

are connected by clamps to the individual tubular well completion string lengths used to form the production strings, either above or below the couplings between the individual lengths of the tubular well completion string, and this gives rise to slippage problems where the well bore deviates substantially from the vertical bore and more particularly in high pressure and sour gas well operations.

Existing clamps do not provide sufficient gripping force or stand off to the tubular well completion string when run in or pulled from wells with high deviation and high dog leg severity.

The present invention seeks to obviate these problems by providing a novel clamp for clamping control lines etc. to the external surface of the tubular well completion string, particularly in the region of and spanning the coupling between the individual lengths of tubing thereby alleviating axial displacement.

The present invention seeks to provide a clamp which holds firmly the control lines and/or cable by utilising the shape formed between the coupling, tubing and clamp.

In accordance with the invention, the novel clamp comprises a semi-circular saddleshaped member adapted to seat on said structure, at least one semi-circular clamping member hingedly connected at one end to said saddle-shaped member and pivotable about the hinge axis from a first, open position in which the clamp may be positioned about the tubular structure to a second closed position in which the saddle-shaped member and the clamping member form an annulus tightly surrounding and gripping the tubular structure, means for releasably fastening the saddle-shaped member and the semi-circular clamping member(s) together into clamping engagement with the external surface of the tubular structure when mounted thereon, and at least one groove or recess formed internally in said clamp and extending longitudinally thereof to accommodate said control lines and/or power cables and to hold same against the periphery of the tubular structure when the clamp is secured thereto.

In one arrangement the clamp comprises two saddle-shaped members hingedly connected together along one longitudinal edge and pivotable about the hinge axis from a first, open position in which the clamp may be positioned about the tubular well completion string, or other tubular substructure, to a second, closed position in which the saddles together form an annulus tightly surrounding and gripping the tubular member, means for releasably fastening the saddle members together into clamping engagement with the external surface of the tubular member when mounted thereon, and at least one groove or recess formed internally in at least one of said saddle-shaped members and extending longitudinally thereof to accommodate said control lines or power cables.Also included in the scope of this invention is a method of securing control lines and/or power cables to a drill string using the novel clamps.

In a second arrangement, the clamp comprises one saddle-shaped member adapted to seat on the tubular structure, with two semicircular clamping members hingedly connected thereto for clamping the saddle-shaped member to the tubular structure.

Two embodiments of the clamps according to the present invention are illustrated in the accompanying drawings in which: Figure 1 is a perspective view of the clamp of the first embodiment in a closed position, as it would be mounted about the tubular well completion string and associated control lines held by the clamp being omitted, and Figure 2 is a perspective view of the clamp of Fig. 1, in an open position.

Figures 3 and 4 are the corresponding views of the second embodiment.

As will be seen, the clamp shown in Figs. 1 and 2 comprises generally saddle-shaped members 1, 2 hingedly connected together at 3 and 4 along one longitudinal edge. Each saddle comprises two semi-circular clamping portions 5, 6 and 7, 8 inter-connected by longitudinally extending connecting bars or ribs 9, 10, 11, 12. The connecting ribs or bars can, of course, extend angularly around substantially the whole circumference at each saddle, i.e. subtend an angle of up to 180 , but simply for economy of metal each will subtend an angle of not more than about 10 to 1 5', with each saddle member comprising two such ribs spaced at 90 one from the other.

Internally, one or both saddle members 1, 2 is or are provided with grooves or channels 13, extending along the length of the saddle and serving when the clamp is in position on the well completion tubular string to accommodate the control or power lines as the case may be, and to hold them firmly against the external surface of the tubular well completion string. Preferably the internal grooves 13 are located in and extend along the length of the connecting bars or ribs 9 which inter-connect the spaced semi-circular clamping portions 5, 6 and 7, 8.

Diametrically opposite the hinged connections 3, 4 between the two saddle members 1, 2 means 15, 16 are provided to fasten the saddle members together and in clamping engagement with the drill string. In the embodiment shown in Fig. 1 the fastening means comprises eye bolts 17. 18 pivotally connected at one end to the two semi-circular clamping members 7, 8 and engageable into recesses 19, 20 formed in the complementary semi-circular clamping members 5, 6 of the opposing saddle member 2. For clarity the eyebolts have been omitted in Fig. 2. As will be obvious, when the clamp is positioned about the drill string, the eyebolts can be moved into mating engagement with the recesses 19, 20 and tightened thereby to secure the clamp firmly about the drill string.

As well as securely fastening the control and/or power lines (not shown) to the drill string the longitudinally extending ribs 9, 10, 11, 12 will serve also to protect the control and/or power lines secured by the clamp and will serve also to centralise the completion tubing within the casing bore.

In the second embodiment shown in Figs. 3 and 4, the clamp comprises a first saddleshaped member of a similar construction to that shown in Fig. 1, but consisting of two spaced apart, semi-circular clamping members 101, 102 inter-connected by three equispaced longitudinal ribs or bars 103, 104, 105. Internally each clamping member 101, 102 is formed with recesses 106 to accommodate the control and/or power lines which are to be secured by the clamp. As will be seen, three such recesses are provided to accommodate control lines of different sizes.

Instead of a single, cooperating clamp member, as shown in the first embodiment, the line clamp of the second embodiment comprises two separate semi-circular clamping members 107, 108 hingedly connected at one end of each of the semi-circular clamping members 101 and 102. Also, instead of the pivoted eyebolts to hold the clamping members together, each of the semi-circular clamping members 107, 108 rotatably carries at its free end a waisted cap screw 109, 110 held captive by a retaining washer 111. 112 and threadedly engageable with a threaded bore 11 3, 114 in the opposing member.

Although obviously the clamps of this invention can be placed intermediate the ends of the individual string lengths, the clamps are specifically designed and are preferably mounted so as to span the coupling between adjacent lengths of the tubular well completion string.

Whilst a variety of materials can be used to construct the clamps of this invention, preferably the clamps will be of cast metal, and preferably a metal or metal alloy that is substantially inert under the conditions encountered in use in the well bore, and particularly in "downhole" sour gas applications.

As will be appreciated the invention provides a very inexpensive but effective saddle clamp which can be mounted externally of a completion string, or other tubular structure, in order to hold control lines, power cables or the like in position thereagainst, and which, in particular, can be mounted in spanning relationship to the couplings between adjacent two lengths. Moreover, the substantially smooth outer surface of the clamp facilitates the feeding of the tubular well completion string with the control lines attached through the production casing.

Claims

1. A clamp for clamping control lines and/or power cables to the external surface of a tubular structure, comprising a semi-circular saddle-shaped member adapted to seat on said structure, at least one semi-circular clamping member hingedly connected at one end to said saddle-shaped member and pivotable about the hinge axis from a first, open position in which the clamp may be positioned about the tubular structure to a second closed position in which the saddle-shaped member and the clamping member form an annulus tightly surrounding and gripping the tubular structure, means for releasably fastening the saddle-shaped member and the semicircular clamping member(s) together into clamping engagement with the external surface of the tubular structure when mounted thereof, and at least one groove or recess formed internally in said clamp and extending longitudinally thereof to accommodate said control lines and/or power cables and to hold same against the periphery of the tubular structure when the clamp is secured thereto.

2. A clamp according to claim 1, wherein the said semi-circular clamping member likewise comprises a semi-circular saddle-shaped member adapted to seat on the tubular structure in diametrically opposed relation to the first saddle-shaped members, the two saddle shaped members being hingedly connected together along one longitudinal edge.

3. A clamp according to claim 1, wherein said saddle-shaped member has two independently movable semi-circular clamping members hingedly connected at the opposite ends of the saddle-shaped member and pivotable about a common hinge axis from said open to said closed position, each such clamping member carrying at its free end means for releasably fastening the clamping member and the saddle member together into clamp ing engagement.

4. A clamp according to claim 1, 2 or 3, wherein the or each saddle-shaped member is constructed of two longitudinally spaced semicircular end members adapted to seat on the periphery of the tubular structure, the two end members being inter-connected by a plurality of integrally formed longitudinal ribs or bars angularly spaced one from the other around the clamp.

5. A clamp according to claim 4, wherein said recess or recesses for accommodating the power and/or control lines are located in axial alignment with said ribs.

6. A clamp according to claim 1, substantially as hereinbefore described with reference to Figs. 1 and 2 or 3 and 4 of the accompanying drawings.

7. A method of securing the control lines and/or power cables to a tubular drill string which comprises attaching the control lines and/or power cables to the drill string by means of a clamp as defined in any one of claims 1-6.

8. A method according to claim 7, wherein the clamp is positioned on the drill string spanning the coupling between individual lengths of tubing making up said string.