WO2004064215A1

WO2004064215A1 - Cable clamps

Info

Publication number: WO2004064215A1
Application number: PCT/GB2004/000111
Authority: WO
Inventors: Philip Head
Original assignee: Philip Head
Priority date: 2003-01-10
Filing date: 2004-01-12
Publication date: 2004-07-29
Also published as: CA2512427A1; GB2398828A; GB0300604D0; GB0400580D0

Abstract

A cable clamp device for use in a well bore to secure cables to pipes and the like, includes a relatively flexible fastening member, and a retaining means that accepts and retains the fastening member. The cable clamp device including a cable restraining means capable of accepting and constraining at least one cable as the cable clamp device is attached to a pipe. This can include flexible resilient parts that deform to accept the cable and thereafter hold it in position, particularly a number of flexible tabs extending approximately perpendicularly to the direction the cable is to run, and capable of flexing deforming toward the direction the cable is to run to accept and hold the cable.

Description

Cable Clamps

The present invention relates to cable clamps for use in a wellbore.

Cables are often used in a downhole environment to conduct electricity, in order to power and control downhole tools and to transmit signals from downhole sensors. When installed with a drill string, the cable is ' often closely secured to the exterior of the tubing so that it is not damaged by the sides of the wellbore as the drill string is lowered. Other types of cable (conduit), such as hydraulic cable and fibre optic cable, may also be disposed in a wellbore.

A known cable clamp comprises two clamp members separated by a bridging section. Each clamp member has two arcuate sections joined by a pivot. The arcuate sections can be opened to accommodate a tubing section with a cable positioned along the pipe section's length, and then closed around the pipe section to encircle it, the free ends of the arcuate sections being joined together by a screw located on the free end of one arcuate section which co-operates with a threaded hole located on the free end of the other arcuate section.

Cable clamps must often be applied to the pipe section and cable in difficult conditions, and it is also important that each clamp can be applied quickly and reliably. It can be difficult to reliably secure the locking mechanism of known clamps, and the cable clamp may be damaged when the user attempts to attach it, so that the cable clamp has to be returned for reconditioning. The object of the present invention is to provide a cable clamp which is convenient to operate. Other advantages will also become clear upon reading the description.

According to the present invention, there is provided a cable clamp device for use in a well bore to secure cables to pipes and the like, including a relatively flexible fastening member, and a retaining means that accepts and retains the fastening member, the cable clamp device including a cable restraining means capable of accepting and constraining at least one cable as the cable clamp device is attached to a pipe.

Preferably the cable restraining means includes flexible resilient parts that deform to accept the cable and thereafter hold it in position.

• According to another aspect of the present invention there is provided a cable clamp device for use in a well bore, including a clamp member comprising a first arm pivotally joined to a second arm, and a fastening means disposed at the end of one or both arms that acts to fasten the arms tightly around a tube, the first arm and the second arm including opposing concave surfaces in proximity to the point the arms are pivotally joined, such that a cable may be secured between and directly abutting both these opposing surfaces as the arms are folded around a pipe section.

The flexible securement member may comprise a loop of wire that is secured to an anchor hook. Alternatively, the flexible securement member may comprise a strip, which engages the first arm and is constrained by a ratchet and pawl mechanism. According to another aspect of the present invention, a cable clamp device for use in a well bore, including a clamp member comprising a first arm pivotally joined to a second arm, and a fastening means disposed at the end of one or both arms that acts to fasten the arms tightly around a tube, the first ami and the second arm including opposing concave surfaces in proximity to the point the arms are pivotally joined, such that a cable may be secured between and directly abutting both these opposing surfaces as the arms are folded around a pipe section.

Preferably the second end is also adapted to fit in series with a tubing section.

The flexible strapping member may be integral and non integral with the cable clamp. Preferably the clamping member is able to accommodate different cable diameters. The clamping member may be reusable, particularly when used with the wire loop fastener; alternatively, it may be disposable, particularly when used with a tie wrap or similar fastener. The retaining strap can be wrapped over the cable or under the cable

Additional items can be distributed along the strap to perform different functions such as centralising the tubing etc. and allow the same strap to be used with centralisers on any size tubing.

Cable clamps according to the present invention will now be described, by way of example, and with reference to the drawings, of which; Figures 1 to 5 are cross sections of the clamp member securing a cable to a pipe section;

Figure 6 is a cross section of another embodiment of a clamp member;

Figure 7 is a cross section of is the clamp member of figure 6 securing a cable to a pipe section;

Figure 8 is a cross section of is another embodiment of a clamp member;

Figure 9 is a cross section of is the clamp member of figure 8 securing a cable to a pipe section;

Figure 10 is a cross section of is another embodiment of a clamp member;

Figure 11 is a cross section of the clamp member of figure 10 securing a cable to a pipe section;

Figure 12 is a cross section of another embodiment of a clamp member securing a cable to a pipe section;

Figure 13 is a cross section of another embodiment of a clamp member;

Figures 14, 15 and 16 are cross sections showing a similar embodiment to that in figure 13 in use.

Figure 17 is a cross section of another embodiment a clamp member; Figure 18 is a side elevation of similar embodiment of a clamp member.;

Figure 19 is a longitudinal sectional view of another embodiment of the clamp member;

Figure 20 is a view of the underside of another embodiment of the cable clamp device.

Figure 21 is a sectional view of the clamp member of Figure 19 in use.

Figure 22 is a sectional view of another embodiment in use.

Figure 23 is a longitudinal sectional view of another embodiment of the clamp member;

Figures 24 and 25 show sectional views of the clamp member of Figure 23 in use.

Referring to figure 1, the cable clamp comprises a first arcuate arm 24, joined to a second arcuate arm 12 by a hinge 18. A locking ami 13 is pivotally joined by a hinge 15 to the second arcuate arm 12. A flexible wire loop is attached to the locking arm 13 by means of the apertures 23 present in the locking arm. The first and second arcuate arms have a curvature approximately the same as the curvature of the tubing they are intended to attach to.

To clamp the cable to the pipe section (or other similar downhole tubular structure), the first arcuate arm is placed upon the exterior of a pipe section 20, subtended nearly 180° of the pipe pipe's circumference. The first arcuate arm includes a slightly curved surface 22 against which a cable 30 is placed. The curved surface 22 has approximately the same curvature as the largest cable that is intended to be clamped. The second arcuate arm 12 includes a U-shaped cut out portion 25. The second arcuate arm 12 is pivoted about the hinge 18 so that the U-shaped cut out portion 25 captures the cable 30, as shown in figure 2.

Referring to figure 3, when the second arcuate arm 12 abuts the exterior of the pipe section, the cable is fully constrained by the U-shaped cut out portion 25 and the curved surface 25 of the first arcuate arm 24, in a position slightly above the tubing exterior. Alternatively, the cable 30 may be constrained by these two surfaces against the exterior of the pipe section.

Referring to figure 4, the wire loop is bent around the exterior of the pipe section and hooked over the anchor point 24 on the first arcuate arm. The locking arm is then drawn round its hinge 15 until it lies against the second arcuate arm (the locking arm having a channel section to accommodate the second arcuate arm). The wire loop is drawn taught by the locking arm, so that the clamp member is tightly secured to the pipe section. As the locking arm 13 pivots around the hinge 15, the surface of the locking ami co-operates with the surface of the second arcuate arm in a cammed manner, so that the locking arm is biased towards either extending away from the second arcuate ami in a substantially co-axial direction as shown in figure 2, or lying against the second arcuate arm as shown in figures 4 and 5. The locking arm therefore cannot disengage without deliberate manipulation; further, as the locking aπn over-centres, the force exerted by the wire loop under tension acts to keep the locking ami closed. When it is necessaiy to release the cable, the tension arm can be lifted, overcoming the biasing, and so de-tensioning the loop wire. The wire loop can then be disengaged from the first arm and the clamp member and cable released.

Referring to figure 6, another embodiment of the clamp member 40 comprises first and second arms 42, 43 joined by a flexible hinge 47. Each arm features a gently concave surface 48 of similar curvature to the exterior of the pipe section, and a more highly curved surface 49 having a similar curvature to the cable intended to be clamped. A standard tie wrap 46 comprises a strip of material having head at one end through which the other end can be introduced to form a loop, the head having a pawl and the strap having a toothed surface. Referring to figure 6, to clamp a cable to a pipe section, the arms 42, 43 of the clamp member are folded together with the cable 30 held against one of the curved surface's 49, until both curved surfaces grip the cable. The surfaces 48 of the clamp member are placed against the exterior of the pipe section, and the tie wrap is placed over channel members (not here visible) extending from each arm the clamp member (and threaded beneath the cable) and rests against the exterior of the pipe section. The free end of the tie wrap is introduced to the head and the strap is pulled through until the tie wrap is tight and both arms of the clamp member are secured against the pipe section, thus securing the cable in position. The channel for the tie wrap may be internal to the clamp member.

Referring to figure 8, one of the arms 52 of the clamp member 50 includes a strap extending from it. Cable is inserted in the clamp member as in previous examples, and the strap is passed through a channel in the arm 53, before being threaded under the cable and inserted in a channel in the arm 52, as shown in figure 9. The end of the strap, which is toothed in the same manner as the tie wrap described above, -co-operates with a pawl 55 in the arm 52 to tightly secure the clamp member to the pipe section and the cable in the clamp member.

The clamp member in this example is preferably manufactured from a plastics material that is sufficiently deformable that the two arms can be integrally moulded, but flex at the thin hinge point between the arms.

When it is necessary to release the cable from the drill string, the tie wrap is severed by sufficiently strong cutters, thereby releasing the clamp member and the cable. After pulling the cut end of the tie wrap past the pawl, the clamp member may be re-used. Alternatively, the clamp member may be discarded, and it can conveniently be manufactured cheaply from plastic, and the flexible hinge described in this embodiment may not be suitable for repeated use.

Referring to figure 10, the clamp member 60 may have internal channels (not shown) and a pawl 60 located near the outer surfaces 67, 68 of the arms 63, 64 of clamp member 60. In use, the strip 66 extending from the arm 53 is introduced into a channel in aim 63, and continue through clamp member into aim 62, co-operating with pawl 65 to secure the cable to the pipe section.

Referring to figure 12, centralising members 47, 48, 49 may be attached to the pipe section in the vicinity of the clamp member, the centralising members being secured by the tie wrap. The centralising members together with the clamp member assist in pipe stand off from the sell bore 100, and distribute support for the tie wrap. It will be seen that the clamp member itself can offer good protection from damage of the cable against the casing or wellbore surface. Conveniently, the tie wrap is threaded through the centralisers. In this way, differently sized centralisers may be attached to the clamping member, and so one size of clamping member may be used with various sized centralisers depending upon the diameter of the casing, and the diameter of the pipe section (the accommodation of different pipe section diameters is discussed below).

Referring to figure 13, the arms 75, 73 of the clamp member 70 may feature notches 76 on the exterior surfaces. This improves the flexibility of the arms, so that the curvature of the surfaces 78, 79 which abuts the pipe section may be varied when the clamp member is folded as shown in figure 14, and so the clamp member 70 may be used to secure cables 30 to pipe sections 20, 18 having different radius, as shown in figures 15 and 16. The tie wrap can of course be tightened to a wide variety of diameters.

Referring again to figure 13, the surfaces 74, 75 for engaging the cable may feature flexible ribs 71. These ribs will secure cables of relatively small section, but deform to accommodate larger cables. Notches 77 could be included in the clamp member to further improve flexibility.

It will be appreciated that the notches 76 which allow variation in pipe diameter, and the ribs which allow variation in cable diameter, may be implemented independently. Referring to figure 17, the tie wrap 91 may be attached to the second arm 92 by inserting a shaped head 94 of the into a co-operating shaped cavity 96 of the second arm 92. Referring also to figure 18, the aperture could be open at one side of the clamping member, to allow the head to be slid into the shaped cavity 96. The tie wrap is then introduced into an aperture 98 in the first arm 93, and pushed along a channel which extends through the first arm and the second aπn to emerge at a longitudinal mouth 95. The tie wrap has saw-tooth shaped surface, the teeth of which engage a indentation 96 in a ratchet fashion to allow the tie wrap to be easily pulled tight but not to be slackened. When the tie wrap has been tightened sufficiently to secure the cable to the pipe section, the excess tie wrap is cut, the mouth 95 ensuring that the knife used does not slid along the surface of the second arm 92.

Ideally, as for all the embodiments described above, the first and second arms encompass only a small portion of the pipe section, typically between 45° and 270°; however, the principles of securement described above could be where the arms encompass or somewhat exceed and overlap the entire circumference of the pipe section.

Cable may be attached to a tube by a number of individual cable clamps each comprising a single clamp member. The cable clamp could also be foπried from two clamp members joined by one or more longitudinal bridging members, or the cable clamp may be extended so that it forms a partial tube, so that the cable clamp offers greater mechanical protection to the cable in that region. In all the embodiments described, the cable has been captured by the folding motion of the pivoted arms of the cable member, and held somewhat from the pipe section. Although this configuration is advantageous, cable could alternatively or additionally also be held a concave surface present on a single arm, pressed directly against the pipe section. Further, because the arms do not have to encompass the entire circumference of the pipe section, they need not be pivotally joined at all, but simply partially accommodate the cable in a concavity and press it to the pipe section.

Refenϊng to figures 19-25, there is shown a flat strap construction for a cable clamp in which the strap receiving portion 120 of the clamp has an angled part 100 having an appropriately angled surface to allow it come into contact with and bear against a tube 101. A number of cable dividers 103 are provided on the strip close to the strap receiving portion 120. Different cable combinations and types can be held by changing the number and location of cable dividers 103; it will be noted that the embodiments shown in figures 19, 21 and 23 show four such dividers (figure 21 illustrating a clamp securing 11x 11 instrumentation lines 130 and ^XA inch control lines 132), whilst those in figures 20, 22, 24 and 25 show three dividers (figure 22 illustrating a clamp securing a 23x11 instrumentation line 134 and VΛ inch control lines 132, figure 24 illustrating a clamp securing a 1.356 inch cable 136 and 11x 11 control lines 138, figure 25 illustrating the same clamp securing a 1.156 inch cable 137 and 11x11 control lines 138).

The cable dividers are preferably integrally formed with the strap in the desired number and position. On the cable dividers are fins 102 which are flexible and conform to the outside diameter of a cable as it is pushed into the gap 104 between adjacent cable dividers 103. The resilient flexibility of the fins ensures that a range of cable shapes and diameters can be accommodated between neighbouring dividers separated at a particular distance. The fins are approximately perpendicular to the cables, but may be slightly angled to aid the cables' insertion. Ideally, the cable clamp is cast in plastic. In order to conveniently cast the cable dividers, in particular the flexible fins, longitudinal slots 122 are provided, so that two sides of the die create the fins and the fins are free to flex. Casting of a different number of cable dividers, or alteration of their position, could conveniently be achieved by adding, removing and/or repositioning moveable/removable components in the die halves that form the cable dividers.

The strap receiving portion 120 also accommodates a pawl 105 for a ratchet. When the front end of the strap (that is, the end of the cable clamp opposite the strap receiving portion 120 of the clamp) is wrapped around the pipe 109 and the cables to be clamped to the pipe, its leading tip 107 is fed into the slot 108 and pulled tight. A hole 112 in the strap allows the operator to use a finger to grip the strap easily and pull on it. Once at the required tensile load any excess is cut off just after the ratchet at 110. The pawl prevents the teeth on the strap from slipping out of the slot, so retaining the clamp securely upon the pipe. A wedge 111 could also be placed behind the strap to provide additional guarantee that the strap could not come undone. . The tube may then for example be deployed in a 7 inch casing 140.

It will be seen that the pawl 105 and the toothed strap could be configured in a number of ways. Figure 21 shows a clamp where the pawl points inwards towards the pipe on which it is attached, and the teeth exposed on the outer surface of the strap as it is wrapped around the pipe. Figure 22 shows a pawl that points away from the pipe, and interacts with teeth provided on the inner surface of the strap as it is wrapped around the pipe. Equally, one or both edges of the strap could be toothed, with a corresponding pawl or pawls in the angled part 100 of the cable.

It will be observed that shape of surface of the angled part 100 may be varied depending upon what type of cable is expected, particularly with regard to the largest cable expected. Thus the cable clamps shown in figures 19, 21 and 22 include a right angled portion 124 suitable for holding a cable square or rectangular section. The cable clamps shown in figure 23, 24 and 25 have a longer angled part without a right angled portion, and are suitable for holding larger round cables. It will be seen that when holding large diameter cables, the angled part of the clamp may be lifted clear of the surface of the pipe 109.

It will be seen that the methods described herein by which the strap may be secured to the strap receiving part and the methods for positioning the cables, may be interchanged in a straightforward manner to create further embodiments; it is particularly comprehended that the cable dividers shown in figures 19 to 25 can be employed within previously described fastening means such as the wire loop and tensioning arm. In the embodiments shown, the clamp member is ideally formed from plastics material, possible with the addition of metal components (for example, where a wire loop is employed). It will be realised however that the embodiments could equally be formed from other material, in particular from metal; thin pieces of metal can for example be conveniently be stamped into the required form, the straps of such clamps being sufficiently defoimable to be wrapped around a pipe.

Claims

1. A cable clamp device for use in a well bore to secure cables to pipes and the like, including a relatively flexible fastening member, and a retaining means that accepts and retains the fastening member, the cable clamp device including a cable restraining means capable of accepting and constraining at least one cable as the cable clamp device is attached to a pipe.

2. A device according to claim 1 wherein the cable restraining means includes flexible resilient parts that deform to accept the cable and thereafter hold it in position.

3. A device according to claim 2 wherein the cable restraining means includes a flexible tab extending approximately perpendicularly to the direction the cable is to run, and capable of flexing deforming toward the direction the cable is to run to accept and hold the cable.

4. A device according to claim 3 wherein the cable restraining means comprises at least two members provided with opposing flexible tabs.

5. A device according to either claim 3 or 4 wherein the cable restraining means is set upon the main body of the device, the main body of the device included apertures corresponding to the position of the flexible tabs.

6. A device according to any previous claim wherein the fastening member comprises a strip, which engages the first arm and is constrained by a ratchet and pawl mechanism.

7. A cable clamp device for use in a well bore, including a first aim pivotally joined to a second arm, and a relatively flexible securement member joined to the second aim, such that a cable can be constrained by the first and/or second arms, and the flexible securement member interact with the first arm to secure the cable relative to the tube.

8. A device according to claim 7 wherein the flexible securement member comprises a loop of wire that is secured to an anchor hook.

9. A device according to either claim 7 or 8 wherein the second ami includes a tensioning arm pivotally attached to the main portion of the second arm, and pivotally attached to the flexible securement member, so „, that after the flexible securement member has been secured to the first arm, • it can be pulled taut by the tensioning aim.

10. A device according to claim 7 wherein the flexible securement member comprises a strip, which engages the first arm and is constrained by a ratchet and pawl mechanism

11. A device according to any of claims 7 to 10 wherein the first and second arms feature a unifomily curved surface to rest against the exterior of a tube, wherein the aims, though less flexible that the flexible securement member, are sufficiently flexible that the unifomily curved surfaces can rest against exterior of tubes having a range of diameters.

12. A device according to claim 11 wherein the aims include notches adapted to aid their flexibility.

13. A device according to any previous claim wherein the first and/or the second am features a uniformly curved surface to rest against the exterior of the cable, said surface being sufficiently deformable to accommodate a range of cable diameters.

14. A device according to claim 13 wherein the ability to deform is achieved by means of flexible protrusions.

15. A device according to any previous claim wherein centring means are included upon the flexible fastening member.

16. A device according to any previous claim wherein centring means are secured by the flexible fastening member.

17. A cable clamp device for use in a well bore, including a clamp member comprising a first aπn pivotally joined to a second arm, and a fastening means disposed at the end of one or both amis that acts to fasten the am s tightly around a tube, the first arm and the^' second arm including opposing concave surfaces in proximity to the point the aims are pivotally joined, such that a cable may be secured between and directly abutting both these opposing surfaces as the arms are folded around a pipe section.

18. A device according to claim 17 wherein the clamp member cable is secured relative to the pipe section but spaced from the exterior surface of the pipe section.

19. A device according to any previous claim, wherein the flexible securement member includes an aperture for the insertion of a digit for the user to tension the cable clamp device.