WO2011121330A1

WO2011121330A1 - Improvements in and relating to pipeline repair

Info

Publication number: WO2011121330A1
Application number: PCT/GB2011/050544
Authority: WO
Inventors: Paul Davidson
Original assignee: Coupling Technology Limited
Priority date: 2010-03-29
Filing date: 2011-03-18
Publication date: 2011-10-06
Also published as: GB2479129A; GB201005224D0

Abstract

Disclosed is an apparatus (10) arranged to isolate a section of pipeline (1) from a fluid being conveyed by the pipeline, the apparatus comprising: an elongate body section (20); a pair of collar sections (30), provided at opposed ends of the body section; a circumferential recess provided in each collar section; a distensible seal provided in each circumferential recess (31); and means (50), operably coupled to each distensible seal (40), for distending the seal (40) so as to cause it to contact an interior surface of the pipeline. Also disclosed in a corresponding method.

Description

IMPROVEMENTS IN AND RELATING TO PIPELINE REPAIR

The present invention relates to a device and method for repairing leaks in pipelines. It finds particular but not exclusive use in oil pipelines, since the economics involved in maintaining and repairing such pipelines renders leaks and their necessary repair of great importance. However, embodiments of the invention can be used in pipelines carrying any of a range of liquids and gasses.

Typically, oil pipelines can stretch for thousands of kilometres across otherwise unspoilt landscapes. Oil companies are always concerned about economic problems associated with leaks in their pipelines, as repairs can involve taking a particular pipeline out of service for a period, which can bring large possible financial losses. Increasingly, though, the oil companies are concerned with environmental issues and the pollution caused by an oil leak, if left untreated for a prolonged period, can cause serious damage to the local environment. Whatever the motivation to repair, there is an increasing need to locate and repair leaks in pipelines in a timely, cost-effective and reliable manner.

Once a leak has become evident from a pipeline, either above or below ground, then a repair time is despatched to effect repairs. Prior art techniques require the pipeline to be closed down for the duration of the repair, which is costly and inconvenient. If the pipeline is located below ground, then excavation equipment must be provided at short notice and transported to the location of the leak.

It is an aim of embodiments of the present invention to address problems associated with the timely and effective repair of pipelines and conduits, whether mentioned herein or not.

According to the present invention there is provided an apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which: Figure 1 shows a cross-sectional view of a pipeline in which is situated a first embodiment of the present invention before the distensible seal is deployed;

Figure 2 shows a cross-sectional view of a pipeline in which is situated a first embodiment of the present invention after the distensible seal is deployed; Figure 3 shows a cross-sectional view of a pipeline in which a second embodiment of the present invention is located, after the distensible seal is deployed; Figure 4 shows a cross-sectional view of a curved pipeline in which a second embodiment of the present invention is located, before the distensible seal is deployed;

Figure 5 shows a cross-sectional view of a curved pipeline in which a third embodiment of the present invention is located, after the distensible seal is deployed; and

Figure 6 shows a cross-sectional view of a pipeline in which is situated a third embodiment of the present invention, before the distensible seal is deployed.

Figure 1 shows a cross-sectional view through a pipeline 1 in which is located an apparatus 10 according to an embodiment of the present invention. The pipeline 1 is live and is conveying a fluid 2 from a first to a second location. Typically, the fluid will be one of an oil, water, a solvent or a gas. It is anticipated that embodiments of the invention will be used mostly in conjunction with oil pipelines, but this is not a limiting feature of the present invention. The apparatus 10 comprises a body section 20 formed from a corrugated section of pipe having a diameter slightly less that the internal diameter of the pipeline 1 , so that it fits in it easily and can be transported or moved to the desired location.

The corrugated section of pipe is formed from a relatively thin walled steel pipe. The corrugations provide strength whilst also providing flexibility, which is necessary so that the apparatus 10 can negotiate bends and junctions in the pipeline 1.

At each end of the apparatus, is an annular collar section 30, having a diameter slightly larger than the diameter of the corrugated section. The collar section can be integrally formed with the corrugated section 20 or may be welded or otherwise attached to the corrugated section 20.

The collar section 30 is provided with a circumferential recess 31 , which runs around the entire circumference of the collar 30. Disposed within the recess 30 is a distensible seal 40.

The seal 40 is formed from nitrile rubber material and resembles a bicycle inner tube. It is a continuous loop but is arranged to have a substantially square or rectangular cross-section to match the recess 31 , unlike the circular cross-section of a typical bicycle inner tube. It is also provided with, at a point on its circumference, a valve 41 . Connected to the valve is a canister 50 of pressurised expandable foam. The expandable foam is of the sort used in widely available tyre-repair kits used to repair a puncture in a vehicle tyre by filling the interior of the tyre cavity with the foam, which acts to seal the puncture and to inflate or otherwise distend the tyre. Alternatively, the canister 50 may contain a pressurised gas alone, which can be used to inflate the seal 40, but more long-lasting results are likely to be achieved if a foam is used also.

In the present embodiment, the foam canister 50 is located adjacent and external to the corrugated section 20 and between the two collar sections 30. Two foam connections are provided such that, once released, foam from the canister 50 can flow into each of the seals 40. Alternatively, two separate canisters 50 can be provided, each associated with only the seal at one particular end of the apparatus 10.

The apparatus 1 is introduced into the pipeline 1 along with a PIG (Pipeline Inspection Gauge) by use of a hydrant system, in a known way. The PIG may be arranged to tow the apparatus 1 behind it until the location of the leak is reached. The location may be determined by telemetry from the PIG, measuring off the distance by means of a tether attached to the PIG, by an optical system provided by the PIG or by any other suitable means.

Once the apparatus 1 is arranged such that its length straddles the leak, then the foam canister 50 can be activated. In the scenario shown in Figure 1 , the leak is located at the position of the weld 3 between two sections of pipeline. In practice, this is the most common location for leaks to occur.

To activate the canister, it is provided with a release cord which, when operated, detaches and opens the valve so that the foam may be conveyed at pressure into one or both seals 40 which then inflate or distend such that their outer surface extends beyond the recess 31 and contacts the interior surface of the pipeline 1. The release cord is operated via suitable functional means on the PIG and, once activated, may be retained by the PIG or released into the pipeline 1.

This situation is shown in Figure 2. Here the seals 40 are completely inflated or distended and their outer surface is in continuous contact with the interior surface of the pipe. This has the effect of isolating the section of pipeline 1 which is situated between the pair of seals 40 and diverting the fluid flow through the body of the apparatus 10. This, therefore, prevents, any further leak from the damaged section of pipe.

Figure 2 also shows that the exposed outer surface of the seal 40 is provided with a plurality of ribs 42 for improving the seal with the interior of the pipeline. Figure 3 shows an alternative embodiment of the present invention. The apparatus 10' is identical with the first embodiment 10, described previously, except a pair of foam canisters 50' are provided, each one of which is connected to a seal 40 at each end of the apparatus. The individual canisters are located within one of the 'valleys' of the corrugated section 20 of the apparatus 10. This arrangement has an advantage over the previous embodiment in that by locating the canisters in this way, rather than longitudinally with respect to the corrugated section, the flexible corrugated section 20 can go around bends in the pipe, so that leaks in elbow sections can be repaired, or bends can be negotiated to reach leaks further down the pipeline.

The fix which is provided in this way can be semi-permanent and can be left in-situ for whatever period is required until a more permanent fix can be arranged. This can be up to several weeks later. Once the leak is repaired permanently, then a further PIG can be dispatched into the pipeline 1 to recover the apparatus 1 and remove it from the pipe.

In some circumstances, it may be possible or even preferable to leave the apparatus in position indefinitely, providing a more or less permanent fix.

The apparatus can be configured to whatever size is needed for a particular task. The main variations are in diameter to fit a particular pipeline and in length. The length can be adjusted according to the extent of damage to the pipe, perhaps being used to repair more than one leak. Another case where a longer apparatus may be required is if one or more bends in the pipe have to be negotiated. Figure 4 shows a scenario where an apparatus 10' is located in an elbow section of pipeline 1 . Here, it can be seen how the corrugations operate to allow the apparatus to follow the bend in the pipe. On the shorter section ("the inside") of the bend, the "ridges" of the corrugated section compress and, on the longer section ("the outside") , the "ridges" are spread out. This allows the apparatus 10' to follow the pipeline, which maintaining its structural integrity.

Once it is located correctly, the foam canisters 50' are activated as described previously to isolate the section of pipeline positioned between the pair of seals 40.

Figure 5 shows the situation when the foam canister 50' have been activated and the seals 40 are fully distended and contacting the internal surface of the pipeline. Figure 5 also shows an alternative configuration of the collar 30, where it has been provided, at each end, with a funnel section 32, which provides a smooth transition between the internal diameter of the pipeline 1 and the internal diameter of the apparatus 10', resulting in less turbulence and no sudden discontinuities which could act to dislodge the apparatus in extreme cases. Figure 6 shows a third embodiment 100 of the present invention. In this embodiment, the apparatus 100 comprises a rigid elongate body, and is suitable for use in a pipeline situation where no bends in the pipe are encountered. The entire body, including collar sections can then be easily formed as a single part if required. The foam canister 50 is located longitudinally between the two collar sections 30 and is coupled to each seal 40, located respectively in each collar section 30.

It will be noted by the skilled person that various features of each embodiment may be combined differently according to the desired use of the apparatus.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. An apparatus arranged to isolate a section of pipeline from a fluid being conveyed by the pipeline, the apparatus comprising: an elongate body section;

a pair of collar sections, provided at opposed ends of the body section;

a circumferential recess provided in each collar section;

a distensible seal provided in each circumferential recess; and

means, operably coupled to each distensible seal, for distending the seal so as to cause it to contact an interior surface of the pipeline.

2. The apparatus as claimed in claim 1 wherein the elongate body section is arranged to be flexible along its length.

3. The apparatus as claimed in claim 1 or 2 wherein the elongate body section is corrugated.

4. The apparatus as claimed in any preceding claim wherein the means for distending the seal comprises one of a pressurised gas and a pressurised foam.

5. The apparatus as claimed in claim 4 wherein the one of the pressurised gas and pressurised foam are contained in a canister which is arranged to release the gas or foam by means of a release cord.

6. The apparatus as claimed in any preceding claim wherein the distensible seal comprises an annular, substantially hollow, elastic member.

7. The apparatus as claimed in claim 6 wherein the seal comprises a rubber material.

8. The apparatus as claimed in any preceding claim wherein the distensible seal comprises a plurality of ribs disposed on a surface and for contacting the interior surface of the pipeline.

9. The apparatus as claimed in any preceding claim wherein the collar sections further comprise funnel sections for providing a smooth transition from the internal diameter of the pipeline to the internal diameter of the elongate body section.

10. A method isolating a section of pipeline, using the apparatus of any preceding claim and comprising the steps of: providing the apparatus and locating it to straddle a defined location; and

activating the means to distend the seal.

1 1. The method as claimed in claim 10 wherein the step of providing and locating the apparatus includes transporting the apparatus inside the pipeline by means of a PIG.

12. The method as claimed in claim 1 1 wherein the step of activating the means to distend the seal includes releasing a release cord.