TUBULAR ISOLATION

Abstract: An apparatus (10) for isolating a section of a bore has two relatively moveable annular sections (12, 14), on which are mounted elastomeric annuli (16, 18). Between the elastomeric annuli (16, 18) is located a third annulus (20) provided in two parts (20a, 20b), with a locating profile (22) provided therebetween. Movement of the annular sections (12, 14) toward one another is effected by means of a setting tool, with the sections being retained in a set position by ratchet surfaces (32, 34) provided on an internal sleeve (26). The elastomeric annuli (16, 18) are thus urged outward to engage and seal a portion of a bore, while the locating profile (22) is also urged outward to locate the apparatus (10) at a desired section of the bore.

Description: TUBULAR ISOLATION The present invention relates to tubular isolation, particularly but not exclusively in the oil and gas exploration and production industries . The invention more particularly relates to an apparatus for isolating a section of a tubular or pipeline. Many industries, such as the oil and gas industry, make use of pipelines for the transport of fluids, both liquid and gas, from place to place. The pipelines used may be many kilometres long, and are typically assembled from pipe sections, the sections being joined together by welds or by some mechanical means such as flanged joints. Over the course of time the joins between sections may deteriorate and may begin to leak. Such leaks may not only lead to the release of contaminants into the environment, but may also render the pipeline unusable until the leak has been repaired. Particularly in the case of underground or subsea pipelines, obtaining access to areas of the pipeline to effect repairs can be difficult and time- consuming. Furthermore, fluid flow often has to be stopped to allow work to take place on the troublesome area of the pipeline; this may also prove costly to the pipeline operator . It is among the objects of embodiments of the present invention to obviate or alleviate these and other disadvantages of existing pipeline systems . According to a first aspect of the present invention, there is provided an apparatus for isolating a section of a tubular from fluid flowing in the tubular, the apparatus comprising two relatively axially moveable annular sections, with an annulus of flexible material disposed therebetween and arranged to extend radially outwards to engage an inner wall of the tubular to either side of the tubular section and isolate the section from fluid flowing in the tubular in response to relative axial movement of the sections. The present invention therefore provides a means whereby a section of a tubular, such as a pipeline, may be isolated while still allowing fluid to flow past the isolated section. The apparatus may be run into a tubular to the appropriate location, and the two annular sections moved towards one another. The flexible material will thus flex or deform outwards and engage with the inner tubular wall, isolating that section of the wall from the remainder of the bore. The annular nature of the apparatus allows fluid to continue flowing through the tubular while the apparatus is located and set in the tubular. Preferably, the flexible material is also resilient. Preferably, the flexible material is substantially impervious to selected fluids; the material may be selected with reference to the fluid carried by a pipeline in which the apparatus is to be located. Conveniently, the flexible material is an elastomeric material, the precise composition of the elastomer depending on the application for which the apparatus is to be used. Preferably the apparatus further comprises portions of relatively inflexible material arranged adjacent to the flexible material. This will assist in ensuring that the flexible material is arranged to flex outwards on setting the apparatus, and serves to reduce the possibility of damage to the flexible material from the annulus. Preferably, the annular sections are selectively relatively axially moveable. Preferably the annular sections are normally relatively moveable only towards one another, towards the set position. Conveniently, this may be achieved by means of a ratchet arrangement provided between the annular sections, most preferably by providing cooperating male and female ratchet portions on the annular sections . Alternatively, the annular sections may be selectively lockable in the set position by means of pins, lock dogs, sprung fingers, screw threads, or the like. Preferably the apparatus further comprises means for selectively allowing the annular sections to move apart from one another. Conveniently this may comprise a quick release mechanism for a locking arrangement, such as a ratchet arrangement or the like. In preferred embodiments of the invention, the apparatus may comprise shear pins or the like, arranged to shear or otherwise fail or release on application of force above a predetermined limit, and release the annular sections from one another. Where the apparatus includes a ratchet arrangement, the arrangement may be formed or mounted on a sleeve or the like mounted on one of the annular sections by shear pins; shearing of the pins allows the ratchet arrangement to disengage, and hence the annular sections to be moved apart. Preferably the apparatus further comprises a profile for engaging a corresponding tool for exerting a shearing force on the pins; this may take place either by direct application of force by a tool or for example by a tool temporarily blocking or restricting fluid flow to create a fluid pressure force on a selected part of the apparatus. Alternatively, where the annular sections of the apparatus engage by means of screw threads, a tool may be used for effecting relative rotation of the sections to engage or disengage the sections. The apparatus may further comprise means for effecting relative movement of the annular sections. Conveniently, for example, this moving means may comprise a hydraulic mechanism or the like, such as an integral piston and cylinder arrangement. The fluid pressure required to set the device may be applied from a remote source, or may utilise the pressure of fluid in the tubular. Alternatively, a pneumatic system, electric, mechanical or other means may be used. Preferably the apparatus comprises two annuli of flexible material disposed between the annular sections, and a third annular section situated between the two flexible annuli. This enables a relatively large section of the tubular located between the flexible annuli to be isolated without the need for a correspondingly large flexible annulus. Certain embodiments of the invention may provide multiple flexible annuli in place of either or both flexible annuli, thereby creating multiple seals at each seal location. Preferably the apparatus comprises a locating profile for engaging a portion of a tubular wall. The portions of pipelines where pipe sections have been joined typically have a distinct shape or profile; a locating profile may be used to engage this portion of the pipeline wall and hence locate the apparatus at the joint between two sections. The locating profile may also or instead be used to locate the apparatus adjacent other selected portions of a tubular having distinct profiles. Selected embodiments of the invention may further comprise means for urging the locating profile outward independently of the flexible annulus; this allows the apparatus to engage a portion of a pipeline without having to seal the portion of the pipeline at the same time. Where the apparatus comprises two flexible annuli, the locating profile is preferably located between the two annuli. The profile may be provided on the third annulus. Preferably the third annulus is in two portions arranged to move toward one another with the annular sections, and further arranged to urge the locating profile outward as the annular sections move together. In this way the locating profile will engage the tubular as the flexible annuli flex outward to engage and isolate the section of the tubular. Alternatively, the locating profile may be located to either side of the flexible annuli. Alternatively, or in addition, means may be provided for selectively gripping or otherwise engaging the wall of the tubular, which means may be integral or separable from the other elements of the apparatus . The apparatus may further comprise means for securing the apparatus to a section of pipeline. Conveniently, for example, each of the relatively moveable annular sections may comprise a pin and box arrangement for securing the end of a pipeline section; other securing means as will be apparent to the skilled person may instead be used. This allows the apparatus to be used to join adjacent sections of pipeline in addition to, or instead of, isolating pipeline sections. According to a further aspect of the invention, there is provided a method of isolating a section of a tubular from fluid flowing in the tubular, the method comprising the steps of : locating in a tubular an apparatus comprising two relatively moveable annular sections, with an annulus of flexible material disposed therebetween and arranged to extend radially outwards in response to relative axial movement of the sections; and moving the annular sections towards one another, such that the flexible material extends radially outwards to engage an inner wall of the tubular to either side of a section of the tubular to isolate the ' section of the tubular from fluid flowing in the tubular. According to a further aspect of the present invention there is provided an apparatus for isolating a section of a tubular, the apparatus comprising first and second relatively axially moveable annular sections, and means for preventing relative axial movement of the sections in one direction, each annular section having a portion of flexible material located on an external surface thereof and abutting a stop, relative axial movement of the sections urging each portion of flexible material against a respective stop such that the flexible material extends radially outwards to engage and isolate a section of a tubular . These and other aspects of the present invention will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 shows an apparatus for isolating a section of a bore in accordance with an embodiment of the invention; and Figure 2 shows a portion of the apparatus of Figure 1 located in a bore in the engaged position. Referring first of all to Figure 1 , this shows an apparatus for isolating a section of a bore in accordance with an embodiment of the invention. The apparatus is shown in its retracted or non-engaged configuration. The apparatus 10 comprises first and second annular sections 12, 14 on which are mounted first and second elastomeric annuli 16, 18. Between the elastomeric annuli 16, 18 is located a third annulus 20, provided in two portions 20a, 20b. Between the third annulus portions 20a, 20b is a sectioned locating profile 22, a circumferential spring 23 tending to retain the profile sections in a retracted position. The profile 22 and third annulus portions 20a and 20b are provided with cooperating angled faces 24a, 24b, 25a, 25b. A sleeve 26 is located internally of the apparatus 10, and is mounted on the first annular section 12 by means of a series of shear pins 28. Sited in a recess 30 on the sleeve 26 is a ratchet collar 32, with a corresponding ratchet surface 34 being provided on the interior surface of the second annular section 14. The sleeve 26 is also provided with an engagement profile 36 for engaging a release tool, as will be described, while the first annular section 12 includes a setting tool engagement profile 38. The operation of the apparatus 10 will now be described, with reference also being made to Figure 2, which shows the apparatus 10 in its engaged configuration located at a flanged joint 42 between two pipe sections 40 r 41. To set the apparatus 10 in the joint 42, a setting tool (not shown) is engaged with the setting tool engagement profile 38 and the end face 43 of the second annular section 14, and the assembly introduced into the pipeline at an appropriate launching point. The setting tool may be self-propelled, or may be mounted on an umbilical. Once the assembly reaches the desired location in the pipeline 40, centrally in the joint 42, the setting tool is actuated to axially compress the apparatus 10. The first and second annuli 12, 14 are brought together, and the ratchet surfaces 32, 34 engage. Compressive force is transferred from the annuli 12, 14 through the elastomeric annuli 16, 18 to the two portions 20a, 20b of the third annulus. These are thus brought together, the angled surfaces 24a, 24b, 25a, 25b causing the locating profile 22 to move radially outwards. When the profile 22 engages with the recess formed by the joint 22, further movement of the third annulus portions 20a, 20b is prevented, while compressive force on the elastomeric annuli 16, 18 causes these annuli to expand outward, to form a sealing contact with the pipeline wall. Seals 44 are provided on the sleeve 26 for engaging the first annular section 12, and on the sections 12, 14 being brought together the leading end of the sleeve 26 engages seals 46 on the second annular section 14. The joint 42 is therefore isolated from the remainder of the pipeline by the set apparatus 10. The setting tool is then disengaged from the apparatus 10 and removed from the pipeline, while the cooperating ratchet surfaces 32, 34 retain the apparatus 10 in the compressed, set configuration . If the apparatus 10 is to be disengaged from the bore 40, a release tool (not shown) is introduced into the bore 40, and located in the release tool engagement profile 36 of the sleeve 26. Axial force is then applied to the sleeve 26 to cause the pins 28 to shear. The sleeve 26 is thus disengaged from the first annular section 12. The compressive setting force is therefore released from the apparatus 10, allowing the annuli 16, 18 to retract, and the spring 23 to retract the segmented profile 22. The various parts of the apparatus 10 may then be removed from the bore 40, to be reused if desired. It will be seen that the foregoing provides an apparatus capable of isolating a leaking section of a pipeline, particularly a pipeline. joint, in a straightforward and reliable manner. The apparatus may be run in and set without difficulty, the compact nature of the apparatus allowing the apparatus to traverse around bends in a pipe system if required. It will be further apparent to those of skill in the art that various modifications and variations may be made to the apparatus herein described without departing from the scope of the invention .

Claims: CLAIMS 1. An apparatus for isolating a section of a tubular, the apparatus comprising two relatively axially moveable annular sections, with an annulus of flexible material disposed therebetween and arranged to extend radially outwards to engage and isolate a section of tubular in response to relative axial movement of the sections. 2. The apparatus of claim 1, further comprising two annuli of flexible material disposed between the annular sections, and a third annular section situated between the two flexible annuli. 3. The apparatus of claim 1, wherein multiple flexible annuli are provided. 4. The apparatus of any preceding claim, further comprising a locating profile for engaging a portion of a tubular wall . 5. The apparatus of claim 4 wherein the locating profile is adapted for engaging a pipeline joint. 6. The apparatus of claim 4 or 5, further comprising means for urging the locating profile outward independently of the flexible annulus . 7. The apparatus of claim 4, 5, or 6, wherein the apparatus comprises two flexible annuli, and the locating profile is located between the two annuli. 8. The apparatus of claim 7 wherein the locating profile is provided on a third annular section situated between the two flexible annuli . 9. The apparatus of claim 8 wherein the third annular section is in two parts arranged to move toward one another with the two annular sections, and the parts being further arranged to urge the locating profile outward as the annular sections move together. 10. The apparatus of any preceding claim, wherein the flexible material is also resilient. 11. The apparatus of any preceding claim, wherein the flexible material is an elastomeric material. 12. The apparatus of any preceding claim, further comprising portions of relatively inflexible material arranged adjacent to the flexible material. 13. The apparatus of any preceding claim, wherein the annular sections are selectively relatively axially moveable . 14. The apparatus of any preceding claim, wherein the annular sections are normally relatively moveable only towards one another, towards the set position. 15. The apparatus of claim 14, further comprising a ratchet arrangement provided between the annular sections . 16. The apparatus of claim 15, wherein the ratchet arrangement comprises cooperating male and female ratchet portions on the annular sections . 17. The apparatus of any preceding claim, further comprising means for selectively allowing the annular sections to move apart from one another. 18. The apparatus of claim 17 wherein the selective moving means comprises releasable couplings arranged to release on application of force above a predetermined limit, and release the annular sections from one another. 19. The apparatus of claim 18 further comprising a profile for engaging a tool for exerting said release force. 20. The apparatus of any preceding claim, further comprising moving means for effecting relative movement of the annular sections to set the apparatus. 21. The apparatus of claim 20, wherein the moving means comprises a hydraulic mechanism. 22. The apparatus of any preceding claim, further comprising means for securing the apparatus to a section of pipeline . 23. A method of isolating a section of a tubular, the method comprising the steps of: locating in a tubular an apparatus comprising two relatively moveable annular sections, with an annulus of flexible material disposed therebetween and arranged to extend radially outwards in response to relative axial movement of the sections; and moving the annular sections towards one another, such that the flexible material extends radially outwards to engage and isolate a section of the tubular. 24. The method of claim 23 wherein the section of tubular is a pipeline joint. 25. The method of claim 23 or 24 further comprising the step of urging an engagement profile outward to engage a wall of the tubular. 26. An apparatus for isolating a section of a tubular, the apparatus comprising first and second relatively axially moveable annular sections, and means for preventing relative axial movement of the sections in one direction, each annular section having a portion of flexible material located on an external surface thereof and abutting a stop, relative axial movement of the sections urging each portion of flexible material against a respective stop such that the flexible material extends radially outwards to engage and isolate a section of a tubular.

Inventors: DUGUID PETER ALEXANDER, DUGUID, PETER, ALEXANDER
Applicants: DUGUID PETER ALEXANDER, SPECIALIST TOOLS & TESTING SER, DUGUID, PETER, ALEXANDER, SPECIALIST TOOLS & TESTING SERVICES LIMITED
Application year: 2001
Main classification: G01M3
IPC codes: E21B29