FIELD OF THE INVENTION

The present invention in genera! relates to an umbilical damp for clamping an umbilical to a tubular structure such as but not limited to a marine riser, in offshore drilling or production sites. The clamp facilitate, clamping of umbilicals in such a manner so that it is supported along practically the entire length of the tubular structure, with the possible exception of across the joints of the structure where series of component members of the structure are attached. In particular, the present invention provides an umbilical clamp according to the preamble of claim 1.

TECHNICAL BACKGROUND OF THE INVENTION

In off-shore drilling operations, tubular structures such as risers are a very common feature,

Risers are known to find its application in off-shore drilling operations for guiding drill pipes and tools to the well bore and for draining mud removed from the well-bore to the surface. Risers are also used to connect a work-over vessel to the Xmas tree for performing various work-over operations in the well. As disclosed in WO/2009/134968 a riser typically comprises a succession of riser pipes, having adjacent ends that are connected and disconnected on the rig to raise and lower the riser into the ocean.

Umbilicals are basically tubes and cables, usually applied for transmitting power, signals and fluids to and from a subsea installation. Such umbilicals are usually clamped to tubular structures, such as but not limited to risers, at the well sites. As will be clear to persons skilled in the art, umbilicals are of immense importance particularly in off-shore drilling operations since transmitting power and fluids in such drilling operations play a significant role in the overall operation. Hence, substantial patent activity has been already witnessed in this context, WO/2010/042873 discloses an ymbilical connectable with a tie back tool and extendable inside a drilling riser, the umbilical being used to communicate with a subsea production tree and down-hole equipment through tie back tool connection with the tree to control fluid flow from well. WO/1988/003596 discloses a submarine umbilical having an end termination in the form of a control module package for controlling a subsea device.

In both the aforesaid patent publications, no emphasis exist on any mechanism for clamping the umbilical to any structure for ensuring smooth functioning. WO/2009/145908 discloses that a hang-off termination of the umbilical is positioned and configured to connect the umbilical to an installation, but here also no emphasis or elaboration exist on the clamping mechanism for the umbilical

WO/2007/064223 discloses a clamping tool for preventing water penetration in critical umbilical guides between preferably an underwater production and processing plant and a control room on shore or on a platform in connection with an underwater umbilical. The clamping tool is designed as a U-shaped claw with an internal movable clamping piston. The piston is meant for applying compression force and flat-clamping a pipe arranged inside the claw between one leg of the claw and the clamping piston. A pulsating movement is applied to the flat- clamped area by means of the clamping tool whereby material flow and internal mechanical fusion cold-weld and seal the pipe's flat clamped area. This arrangement ensures prevention of water penetration in umbilical guides.

WO 2008/152372 describes a clamp for clamping an umbilical to a tubing. The clamp is bulky and consists of a multitude of parts. The clamp must be mounted manually on the tubing and the attachment of the umbilical must also be done manually. This means that the attachment of the umbilical to the tubing is very time consuming. Consequently, the damp of this publication is costly both to produce and to use.

US 7093858 describes a resilient clamp for attachment of a wire to a tubing. The wire must be threaded from one end to the other through the bore adapted to receive the wire. This is only possible for relatively short lengths of wires. It would be practically impossible to thread an entire umbilical this way.

Although the inventions disclosed in the patent publications as acknowledged in the preceding paragraph essentially focus on clamping/attachment mechanism of an umbilical, no emphasis or clear teaching exists for continuous clamping of an umbilical along a tubular structure in an off-shore drilling operation site, so that the umbilical is supported continuously along practically its entire length. No teaching also exists in such documents to ensure easy attachment and detachment of umbilicals to and from the tubular structures, such as but not limited to risers, to which such umbilicals are clamped. In general, the clamping mechanisms in vogue for clamping umbilicals to tubular structures comprise umbilicals clamped to the structure such as a riser using separate clamps at intervals along the riser, for example as disclosed in WO/2009/134986.

Hence, there was a long felt need to design an umbilical clamp for clamping umbilicals along a tubular structure, such as but not limited to risers so that the umbilical is supported continuously along practically its entire length. The umbilical clamp according to the present invention meets this long felt need and other needs associated therewith and the design of the umbilical clamp as disclosed hereinafter is consequential to the present invention.

OBJECTS OF THE INVENTION The present invention aims to meet the above need hitherto not taught by prior art by providing a specially designed umbilical clamp for clamping an umbilical along a tubular structure, which clamp by virtue of its specially configured design ensures that the umbilical is supported along practically its entire length. Another object of the present invention is to provide an umbilical clamp which substantially prevents twisting of the umbilical along a tubular structure. It is another object of the present invention is to provide an umbilical clamp which substantially protects the umbilical from impact.

Another object of the present invention is to provide an umbilical clamp which ensures easy attachment and detachment of the umbilical to and from the tubular structure, along which the umbilical is clamped.

A further object of the present invention is to provide an umbilical clamp for clamping an umbilical along a riser in an off-shore drilling operation, which clamp by virtue of its specially configured construction ensures that the umbilical is supported along practically its entire length.

Another object of the present invention is to provide a tubular structure/riser having at least one umbilical clamped in a practically continuous manner along its length by means of a specially configured clamping mechanism.

In addition, the present invention discloses some advantageous features still not disclosed in prior art.

All through the specification including the claims, the words "tubular structure", "riser ^* ', "umbilical", "clamp", "wheel", "slot", "rubber strip", "band" and "perforations/grooves" are to be interpreted in the broadest sense of the respective terms and includes all similar items in the field known by other terms, as may be clear to persons skilled in the art. Restrictions / limitations if any referred to in the description are solely by way of example and understanding the present invention. Further it should be understood to persons skilled in the art that the umbilical clamp according to the present invention is adapted to be attached to any type of tubular structures as applied in off-shore drilling locations and as known to persons skilled in the art. The clamping mechanism has been explained in the present specification, with reference to risers only for the sake of understanding the invention and the present invention is not limited to such risers only.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided an umbilical clamp for connecting at least one umbilical along a tubular structure, the clamp comprising a first member and at least one second member. Said first member Is an elongated unit provided with at least one slot for accommodating said umbilical firmly therein and said first member is adapted to be attached along said tubular structure by at least one said second member, thereby forming a continuous clamping arrangement for said umbilical, along said tubular structure.

Preferably, said first member comprises an elongated elastic strip, e.g. rubber, having a slot for receiving the umbilical. This provides a firm and protective grip on the umbilical

In one embodiment, said second member comprises at least one band adapted to extend around said tubular structure. This is a simple and easy way to attach the strip. Preferably, said elastic strip is detachably attached on said tubular structure by at least two said bands. This ensures that the strip is prevented from twisting.

Preferably, each said rubber strip has at least two transverse channels for receiving two said bands. This ensures a firm grip between the bands and the strip. In an alternative embodiment said second member comprises a sleeve which is formed integral with said elastic strip. This creates an excellent grip between the strip and the tubular. In a preferred application of the clamp, the tubular structure is a part of a riser having successively connected riser joints and said clamp forms a continuous clamping arrangement for said umbilical along the entire length of said riser joint, between end fittings of said riser joints. In one embodiment the elastic strip has flat edges at either side of said slot for receiving the umbilical and that said slot is wider close to at least one end of said elastic strip.. This facilitates the insertion and removal of the umbilical.

In an alternative embodiment the elongate rubber strip is provided with fingers next to said slot for receiving the umbilical. This ensures a firm grip on the umbilical while also facilitating the insertion and removal of the umbilical.

The invention also comprises a tool for inserting an umbilical into and removing the umbilical from the umbilical clamp, comprising a wheel with a groove adapted to receive the umbilical and that the wheel is adapted to press against said elastic strip to guide the umbilical into and out of the slot in the elastic strip. By this tool strain on the umbilical is greatly reduced and the insertion and removal of the umbilical can be automated.

SHORT DESCRIPTION OF THE FIGURES

Having described the main features of the invention above, a more detailed and non-limiting description of some exemplary embodiments will be given in the following with reference to the drawings, in which

Figure 1 is an enlarged view of the umbilical clamp according to a preferred embodiment of the present invention. Figures 4a and 4b illustrate a further alternative embodiment of the present invention, wherein the clamp is moulded around the pipe.

DETAILED DESCRIPTION OF THE !NVENTION

As stated hereinbefore, the principal objective of the present invention is to provide a clamping mechanism for clamping an umbilical along a tubular structure in an off-shore drilling location, so that the umbilical is supported along practically its entire length along the tubular structure.

The clamping mechanism has been explained hereinafter, with reference to risers only for the sake of understanding the invention and the present invention is not limited to such risers only. It may be applicable on other tubular structures. Further, description of the first member and second member of the clamping mechanism as provided hereinafter is purely for the sake of understanding the present invention and not by way of any sort of limitation. It should be understood to persons skilled in the art that there may be other first members and second members for ensuring continuous support for the umbilical along its entire length and the present invention encompasses, all such alternatives.

As illustrated in the accompanying figure 1 the clamping mechanism comprises a first member in the form of a rubber clamp 3 and a second member in the form of a stainless steel band 2. The umbilical 1 runs along the entire length of the riser 8. The umbilical clamp comprising the rubber clamp 3 and the band 2 ensures that the umbilical 1 is supported continuously along its entire length. For that purpose, as it will be understood by persons skilled in the art, there should be a plurality of rubber clamps 3 attached onto the surface of the riser 8 by at least one band 2, each rubber clamp 3 having at least one band 2, but preferably a plurality of bands, for ensuring sufficient attachment of the rubber clamp 3 to the riser 8. Preferably, there are at least two such bands. This is further illustrated in the accompanying figure 2a and figure 2b. The rubber For that purpose, as it will be understood by persons skilled in the art, there should be a plurality of rubber clamps 3 attached onto the surface of the riser 8 by at least one band 2, each rubber clamp 3 hawing at least one band 2, but preferably a plurality of bands, for ensuring sufficient attachment of the rubber clamp 3 to the riser 8. Preferably, there are at least two such bands. This is further illustrated in the accompanying figure 2a and figure 2b. The rubber clamps 3 are preferably provided with transverse channels 2', as illustrated in the accompanying figures 3a and figure 3b for the bands 2 to pass through and provide the grip around the riser 8. How the bands 2 provide the grip around the riser 8 would in particular be very clear from the accompanying figures 2a and 2b. The umbilical is thus provided continuous support along practically its entire length with the only exception being across the joints of the riser. As stated in the preceding paragraph, the bands may be plastic bands as well. The number of bands can vary depending on the strength of the band. Generally, a large number of bands, and hence short distance between the bands, reduces the requirement for strength of each band. The rubber strip 3 is preferably made by extrusion much the same way as boat fenders are made.

The accompanying figure 3c which is an enlarged view of the rubber clamp 3 illustrates that each rubber clamp is an elongated tubular enclosure having a continuous slot 7 with flat edges along the axis of the tubular enclosure, a grooved inner wall 7' and narrowed central portion 7".

Figure 3c shows a view where an enlarged view of only one end is shown, while the other end is not shown. Figure 3d shows a full picture of the rubber strip 3 showing both the ends. The accompanying figures 3a and 3b illustrate another embodiment of the elongated rubber strip 2 where consecutive fingers 6 are provided on the top surface thereof for ensuring firm holding of the umbilical. This embodiment makes it easier to press the umbilical into the groove 7 and to remove it again.

Figures 4a and 4b show an alternative embodiment of the clamp according to the present invention. Instead of attaching the rubber strip 3a with separate bands to the riser, the rubber strip 3a has a sleeve 3 made integral with the rubber strip 3a. The sleeve 9 is preferably moulded around the riser tube 8 between the end fittings / joints of the riser. Between the sleeve 9 and the strip 3a are formed grooves 10. The grooves 10 provide room for the strip to bend when an umbilical is pressed into the groove 7a.

The clamping mechanism as described hereinabove ensures continuous clamping of the umbilical along its entire length by means of continuous support. This was hitherto not envisaged or achieved. This arrangement thus ensures that the umbilical will be supported practically along its entire length. Consequently, it will be prevented from ^' twisting as is known to happen on applications of current umbilical clamps. The clamping mechanism according to the present invention also ensures better protection against impact.

With the present invention is also facilitated easy attachment and detachment of the umbilical to the riser and for that purpose a driven or non-driven wheel 5 may be placed next to the rubber strip 3, as illustrated in the accompanying figures 2a and 2b. The wheel is rotatably suspended on an arm (not shown) that presses the wheel against the rubber strip. Consequently, the umbilical will be pressed into the longitudinal slot of the rubber strip by the wheel 5. The wheel will also facilitate removal of the umbilical from the rubber strip. The wheel reduces the bending and stress on the umbilical, and hence both insertion and removal of the umbilical can take place with little chance of damage to the umbilical.

It will be understood to persons skilled in the art that in a well site several such umbilicals may be attached to one or more tubular structures/risers and for the sake of simplicity, only one umbilical is illustrated in the accompanying figures. The present invention also encompasses a tubular structure/riser having at least one umbilical clamped in a continuous manner along its entire length by means of the clamping mechanism as described hereinabove. The present Invention has been described with reference to some preferred embodiments and some drawings for the sake of understanding only and it should be clear to persons skilled in the art that the present invention includes all legitimate modifications within the ambit of what has been described hereinbefore and claimed in the appended claims.