Downhole protection apparatus

Abstract

A downhole protection apparatus, for use in protecting downhole control lines, comprises a sheath defining a channel configured to receive a control line. The sheath is configured to be attached to a tubing. In wellbore applications, the control lines associated with a tubing are inserted into the sheath such that the body of the sheath at least partially encompasses the control line and shields the control line from harsh downhole conditions which may include abrasive action from sand, proppants, wellbore cuttings and other debris. Therefore, the apparatus is configured such that after insertion of a control line into the channel, a body of the sheath protects the control line from an outside environment.

Claims

1. A downhole protection apparatus for use in protecting downhole control lines, comprising: an elongate reelable sheath defining a channel configured to receive a control line, and shield said control line when the apparatus is mounted adjacent a length of tubing of a downhole assembly, the elongate reelable sheath and control line being separately reelable, wherein the elongate reelable sheath defines an entrance to the channel that extends longitudinally along the elongate reelable sheath, the elongate reelable sheath being mountable to an outer surface of a tubing such that the entrance of the channel faces the outer surface of that tubing.

2. The downhole protection apparatus according to claim 1, wherein the elongate reelable sheath comprises or is formed of a resilient and/or an elastic material.

3. The downhole protection apparatus according to claim 1, wherein the elongate reelable sheath comprises rubber.

4. The downhole protection apparatus according to claim 1, wherein the elongate reelable sheath is in a form of a rib configured to extend longitudinally along a length of tubing.

5. The downhole protection apparatus according to claim 1, wherein the elongate reelable sheath comprises at least one of a shock-absorbant material, a lattice structure, a porous structure, a honeycomb-like structure, or is inflatable.

6. The downhole protection apparatus according to claim 1, wherein the elongate reelable sheath comprises a swellable material, the swellable material being swellable in oil or water.

7. The downhole protection apparatus according to claim 1, wherein the elongate reelable sheath comprises a non-swellable material.

8. The downhole protection apparatus according to claim 1, wherein a surface profile of the elongate reelable sheath is configured to engage with an outer surface of a tubing.

9. The downhole protection apparatus according to claim 1, wherein at least one of (1) the channel extends along the same axial direction as the elongate reelable sheath, and (2) the channel is in a form of a slot and is coterminous with the elongate reelable sheath.

10. The downhole protection apparatus according to claim 1, wherein at least one of (1) the elongate reelable sheath is configured such that the channel comprises a variable dimension and (2) material defining the channel is resiliently and elastically deformable.

11. The downhole protection apparatus according to claim 1, further comprising: an outer cover.

12. The downhole protection apparatus according to claim 11, wherein the outer cover extends continuously along a length of the elongate reelable sheath.

13. The downhole protection apparatus according to claim 11, wherein the outer cover extends discontinuously along a length of the elongate reelable sheath.

14. The downhole protection apparatus according to claim 11, wherein the outer cover is at least one of mountable to a clamping member or integrally formed with a clamping member.

15. The downhole protection apparatus according to claim 1, wherein the elongate reelable sheath is directly attachable to an outer surface of a tubing by at least one of adhesion, fusing, welding, vulcanization, interference, or a cooperating profile.

16. A downhole protection apparatus according to claim 1, wherein the entrance to the channel is located between the channel and a length of tubing.

17. A downhole assembly comprising: a tubing; a downhole protection apparatus mounted along a length of the tubing, the downhole protection apparatus including, an elongate reelable sheath defining a channel, the elongate reelable sheath defining an entrance to the channel that extends longitudinally along the elongate reelable sheath, the elongate reelable sheath being mounted to an outer surface of the tubing such that the entrance of the channel faces the outer surface of the tubing; and a control line inserted into the channel; the elongate reelable sheath and control line being separately reelable.

18. The downhole assembly according to claim 17, wherein the downhole protection apparatus further comprises: an outer cover.

19. The downhole assembly according to claim 18, wherein the outer cover is mounted to an outer surface of the elongate reelable sheath.

20. The downhole assembly according to claim 17, wherein the downhole assembly further comprises: at least one of a clamping member or a plurality of clamping members.

21. The downhole assembly according to claim 20, wherein the clamping member is configured to attach the downhole protection apparatus to the tubing.

22. The downhole assembly according to claim 20, wherein an outer cover is at least one of circumscribed by the clamping member, mounted onto the clamping member, or integrally formed with the clamping member.

23. A downhole protection apparatus according to claim 17, wherein the entrance to the channel is located between the channel and a length of tubing.

24. A method for preparing a tubing for a downhole assembly comprising: mounting a downhole protection apparatus to the tubing, the downhole protection apparatus including, an elongate reelable sheath defining a channel, the elongate reelable sheath defining an entrance to the channel that extends longitudinally along the elongate reelable sheath, the elongate reelable sheath being mounted to an outer surface of the tubing such that the entrance to the channel faces the outer surface of the tubing; and installing a control line into the channel defined by the elongate reelable sheath the elongate reelable sheath and control line being separately reelable.

25. The method for preparing a tubing according to claim 24, wherein the installing the control line occurs at least one of before the mounting, after the mounting, or contemporaneously with the mounting.

26. The method for preparing a tubing according to claim 24, further comprising: attaching an end of the tubing to an end of another tubing to form a tubing string.

27. The method for preparing a tubing according to claim 24, wherein the downhole protection apparatus is provided in at least one of a rolled form or in a form of discrete elongate sections.

28. The method for preparing a tubing according to claim 24, further comprising: unrolling the downhole protection apparatus from a reel and mounting the apparatus continuously onto the tubing.

29. The method for preparing a tubing according to claim 24, further comprising: cutting discrete lengths of downhole protection apparatus from a reel, and mounting the discrete lengths onto the tubing.

30. The method for preparing a tubing according to claim 24, further comprising: providing the elongate reelable sheath with an outer cover.

31. The method for preparing a tubing according to claim 24, further comprising: mounting the downhole protection apparatus to a plurality of clamping members, and selectively attaching the plurality of clamping members at discrete points along the length of the tubing.

32. A method for installing a downhole assembly comprising: mounting a downhole protection apparatus comprising an elongate reelable sheath to a tubing; installing a control line into a channel defined by the elongate reelable sheath, the elongate reelable sheath defining an entrance to the channel that extends longitudinally along the elongate reelable sheath, the elongate reelable sheath being mounted to an outer surface of the tubing such that the entrance of the channel faces the outer surface of the tubing, the elongate reelable sheath and control line being separately reelable; attaching an end of the tubing to an end of another tubing to form a tubing string; and running the tubing string downhole.

33. A method for protecting a control line in a downhole environment comprising: providing a downhole protection apparatus comprising an elongate reelable sheath, the elongate reelable sheath defining a channel and an entrance to the channel, the entrance extending longitudinally along the elongate reelable sheath, the elongate reelable sheath being mountable to an outer surface of a tubing such that the entrance to the channel faces the outer surface of the tubing; and installing the control line into the channel; the elongate reelable sheath and control line being separately reelable.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 illustrates a section of borehole with a tubing string extending therethrough;

(3) FIG. 2 is a cross-sectional view of a downhole protection apparatus according to an embodiment of the invention, shown in use mounted on a section of tubing;

(4) FIG. 3 is a perspective view of a downhole protection apparatus in accordance with an embodiment of the present invention;

(5) FIG. 4 is a schematic representation of a method of mounting a downhole protection apparatus and control line to a section of tubing string according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) In FIG. 1, a section of wellbore or borehole 12 is shown extending through a formation 14. Although, in this embodiment the invention is shown in use in an open hole application, embodiments of the invention can be used in a similar fashion in cased, lined, cemented etc. wellbore operations.

(7) A tubing string 16, e.g. a production tubing, extends through the wellbore 12 defining an annulus 17 between the outer surface of the tubing string 16 and the wall of the wellbore 12. The tubing string 16 allows communication of fluids between the surface and the formation, for example, the tubing string 16 may facilitate communication of hydrocarbons to the surface and/or may act as a conduit to allow injection of fluids, such as fracturing fluids, from surface.

(8) Pairs of packers 18 are positioned in the annulus 17 between the wellbore 12 and the tubing string 16. The packers 18 isolate different zones of the annulus 17 from one another and allow selective downhole operations, such as production, injection, fracturing or the like, from different zones along the wellbore.

(9) Bundles of control lines 20 are associated with the tubing string 16 and enable surface control of downhole tools and apparatus at different locations along the wellbore 12. For example, control lines may enable communication between the surface and downhole locations, and/or may enable the transmission of control signals and/or power to downhole tools and apparatus. The bundles of control lines 20 are held in a downhole protection apparatus 26 according to an embodiment of the invention, which is shown in more detail in FIGS. 2 and 3. The downhole protection apparatus and control lines are held to the tubing string 12 by several clamps 22 which are positioned at discrete positions along the tubing string 12.

(10) The section of tubing string 16 comprises controllable ports 24, e.g. fracturing and/or inflow ports. In fracturing operations, the ports 24 are opened and fracturing fluids are pumped downhole through the ports to the formation 14 via the annulus 17 at high pressures. Fracturing fluids are highly abrasive, containing large quantities of proppants and sand. In addition, in some wellbore applications, such as cased or lined hole applications, perforation guns can be used to perforate the borehole 12 to facilitate production. The action of perforating can mean that control lines held in the annulus are subjected to high shock loads. Consequently, it is clear that conditions in the annulus 17 can be fierce and hostile to the control lines 20 held on the outside of the tubing string 12.

(11) The downhole protection apparatus of the invention comprises a sheath 30 to shield the bundles of control lines 20 from the fierce conditions that they would otherwise be exposed to in the annulus 17. Therefore, protection of the control lines 20 using embodiments of the invention can effectively extend the operational life of the wellbore.

(12) As shown in FIGS. 2 and 3, the downhole protection apparatus 26 comprises a sheath 30 defining two channels 32 which are each independently configured to receive a control line or a bundle of control lines 20.

(13) In the embodiment shown in FIG. 2, a hinged clamp 22 circumscribes the tubing string 16. The sheath 30 is positioned over the clamp 22 and is held in position by an outer cover 28 mounted to the sheath. The outer cover 28 extends continuously along the length of the sheath 30 and, in this embodiment, the outer cover 28 is configured to engage with the clamp 22 via an interference fit mechanism. In other embodiments, the outer cover 28 may be attached to the clamp 22 by adhesion, fusing, welding, vulcanization, a cooperating profile or the like.

(14) In other embodiments of the invention, the clamp 22 circumscribes the sheath 30 and outer cover 28 and in this way clamps or grips the downhole protection apparatus 26 to the tubing string 16. In further embodiments, the outer cover 28 is formed integrally with the clamp 22. In addition, in some embodiments, the outer cover 28 is hinged to allow ease of installation onto the sheath 30.

(15) The sheath 30 is an elongate body defining two channels 32 which are each independently configured to receive a control line or a bundle of control lines 20. In the embodiment shown in FIG. 3, each channel 32 is configured to receive a bundle of control lines, e.g. two or more control lines. However, in other embodiments, each channel is configured to receive only one control line 20. In further embodiments, the channels 32 are sized differently from one another such that each channel 32 is configured to receive different numbers of control lines 20 or control lines 20 of different sized diameter.

(16) The sheath 30 is made of a resilient and elastic material, such as rubber, e.g. synthetic rubber or natural rubber. The sheath 30 is made of a shock absorbant material. In the embodiment shown in FIGS. 2 and 3, the sheath 30 protects the control line 20 from impact forces, collisions, shock loads and the like. As will be appreciated, in other embodiments, the sheath 30 can comprise a physical and/or mechanical structure that acts to absorb shock, e.g. a lattice, honeycomb-like or porous structure.

(17) The sheath 30 is in the form of a longitudinal rib configured to extend along a length of tubing string 16. The sheath 30 is profiled on at least one face to engage with the surface of the clamp 22. In other embodiments, the sheath 30 is profiled on at least one face to engage with the surface of the tubing string 16. Another face of the sheath 30 is profiled to engage with the outer cover 28, when present in the apparatus.

(18) Although in the illustrated embodiment, the sheath 30 comprises two channels 32, it will be appreciated that the sheath may comprise one channel or any number of channels greater than one.

(19) The channels 32 are parallel to one another and extend along the same axial direction as the sheath 30. The channels 32 are in the form of a continuous slot extending along the length of the sheath. The slots comprise an entrance portion which extends into an enlarged head portion which is configured to house the control lines 20.

(20) The sheath 30 is configured such that after insertion of the control lines 20 into the channels 32, the elasticity and/or resiliency of the sheath body effectively seals the control lines within the body of the sheath 30. In use, after the sheath 30 has been mounted onto the clamp 22, the outer cover 28 imparts a compressive force onto the sheath 30, causing the channel entrances to be compressed and effectively sealing the control lines 20 within the body of the sheath 30. In this way, the sheath 30 can provide a physical barrier between the control lines 20 and an external environment.

(21) A method of preparing a section of tubing string 16 for a downhole assembly is shown schematically in FIG. 4.

(22) As shown in FIG. 4, a section of tubing 33 is held in position above a platform 34 e.g. a rig floor. A control line or bundle of control lines 20 are wound around a drum or reel 36. The downhole protection apparatus 26 is provided in rolled form, e.g. in FIG. 4, the downhole protection apparatus 26 is wound around a drum or reel 38. The flexibility of the downhole protection apparatus 26 allows the downhole protection apparatus 26 to be compactly stored and transported on drums, such as reel 38. The provision of the downhole protection apparatus on such a reel also allows for ease of installation onto a tubing string 16, as is described in detail below.

(23) The method comprises mounting a downhole protection apparatus 26 comprising a sheath 30 to a section of tubing 33 and installing, for example by insertion, a control line, or bundle of control lines, 20 into a channel 32 defined by the sheath 30.

(24) In the embodiment shown in FIG. 4, for each section of tubing 33, a section of control line(s) 20 is unwound from the reel 36 and installed, e.g. by insertion, into a channel 32 defined by the sheath 30 of the downhole protection apparatus 26. After insertion of the control line(s) 20 into the sheath 30, the assembly of the sheath and control line(s) is mounted to the section of tubing 33.

(25) As will be appreciated, whilst in this embodiment the control line(s) 20 is installed into the downhole protection apparatus 26 prior to mounting on the section of tubing 33, it is also possible to first mount the downhole protection apparatus to the section of tubing 33 and subsequently install the control line(s) 20, or, alternatively, to carry out the two steps of mounting and installing simultaneously.

(26) In the embodiment shown in FIG. 4, the sheath 30 is mounted and/or attached to an outer surface of the section of tubing 33 such that the entrance of the channel 32 contacts the outer surface of the section of tubing 33. In this embodiment, the step of inserting the control line(s) 20 into the sheath 30 is carried out before, or simultaneously with, the step of mounting the sheath 30 to the section of tubing 33. It will be appreciated that, in other embodiments, the sheath 30 can be attached to the section of tubing 33 such that the entrance of the channel 32 opens to an outside environment. In these embodiments, the step of inserting the control lines(s) 20 is carried out before, after, or simultaneously with the step of mounting the sheath 30 to the section of tubing 33.

(27) During installation of the downhole protection apparatus 26 on a section of tubing 33, reels 36 and 38 are positioned in a parallel line to the section of tubing 33 and adjacent to the section of tubing 33. In this arrangement, as the control lines 20 and the downhole protection apparatus 26 are unwound from reels 36 and 38 respectively, the unwound sections of control line and apparatus 26 align with the length of the section of tubing 33. This facilitates both mounting the apparatus 26 onto the section of tubing 33 and also insertion of the control line 20 into the sheath 30 of the apparatus 26.

(28) Alternatively, the downhole protection apparatus 26 may be provided in the form of discrete elongate sections which can be stacked, for example in pallets or the like, on the rig floor 34 and mounted individually onto the section of tubing 33. In either case, particular lengths of the downhole protection apparatus 26 can be obtained by cutting the apparatus 26 to size prior to mounting on the section of tubing 33. In this way, different lengths of downhole protection apparatus can be mounted to different sections of the tubing string 16 if so desired.

(29) As shown in FIG. 4, after the downhole protection apparatus 26 comprising a control line, or bundle of control lines, 20 has been mounted to a section of tubing 33, the method comprises securing a clamp 22 over the downhole protection apparatus 26 which holds downhole protection apparatus 26 in position on the tubing 16. However, as will appreciated from the foregoing description, the attachment of the downhole protection apparatus 26 to a section of tubing 33 can be effected in many different ways, including by welding, vulcanization, adhesion, cooperating profiles and/or an interference fit with the outside of the clamp 22.

(30) Although not illustrated in FIG. 4, in some embodiments, an outer cover 28 can be mounted onto the downhole protection apparatus 26, before or after the apparatus 26 is mounted onto the section of tubing 33, or the step of mounting the outer cover 28 can be carried out simultaneously with the step of mounting the apparatus 26 onto the section of tubing 33.

(31) After installation of the downhole protection apparatus 26 on a section of tubing 33, the method comprises lowering the section of tubing 33 into a borehole 12.

(32) After mounting and attaching the downhole protection apparatus 26 to a section of tubing 33, the method can further comprise attaching an end of the section of tubing 33 to the end of another section of tubing in order to form a tubing string 16 and then running the tubing string 16 downhole (as shown in FIG. 1).

(33) In some embodiments, the downhole protection apparatus 26 runs continuously along the entire length of the tubing string 16. Alternatively, the downhole protection apparatus 26 is selectively applied to different sections of tubing string 16. For example, the downhole protection apparatus 26 can be applied to sections of tubing string 16 where fracturing and/or perforation is intended to be performed. As described above, the downhole protection apparatus 26 can be cut to a desired length prior to mounting the downhole protection apparatus 26 on a section of tubing 33.