Well intervention apparatus and method

Abstract

Well intervention apparatus is provided, the well intervention apparatus including a flexible hose to be lowered into a well, a stuffing seal which engages around the hose during lowering, at least one tool provided at a downhole end portion of the hose, and a plurality of individual tubes extending along an inside region of the hose and connecting to the at least one tool, each individual tube providing a fluid path for fluid communication between outside of the well and the at least one tool inside the well, and each individual tube being laterally supported in said inside region such that its lateral movement is restricted.

Claims

1. A well intervention apparatus comprising a flexible hose to be lowered into a well, a stuffing seal which engages around the hose during lowering, at least one tool provided at a downhole end portion of the hose, a plurality of individual tubes extending along an inside region of the hose and connecting to the at least one tool, each individual tube providing a fluid path for fluid communication between outside of the well and the at least one tool inside the well, and each individual tube being laterally supported in said inside region such that its lateral movement is restricted; and a bottom hole assembly disposed at the downhole end portion of the hose, said bottom hole assembly having a sealing arrangement that includes a seal disposed around the downhole end portion of the hose, and a pair of wedge members, each wedge member extending a circumferential distance around the hose, wherein the sealing arrangement is configured so that the wedge members compress the seal into sealing engagement with the hose.

2. The well intervention apparatus of claim 1, comprising a flexible material in the inside region to provide said lateral support to the individual tubes.

3. The well intervention apparatus of claim 1, wherein the bottom hole assembly comprises a termination assembly for the hose.

4. The well intervention apparatus of claim 3, wherein the hose extends into a body of the termination assembly, and the seal around the downhole end portion of the hose is provided in a cavity in the body of the termination assembly.

5. The well intervention apparatus of claim 4, wherein the seal is compressed between the outside of the hose and the body of the termination assembly, and wherein the body of the termination assembly extends circumferentially around the hose.

6. The well intervention apparatus of claim 5, wherein the pair of wedge members are axially movable and each wedge member is configured so that when the respective wedge member is moved axially towards the seal, the seal is caused to engage in sealing manner between the outside of the hose and the body.

7. The well intervention apparatus of claim 3, wherein the inside region of the hose is open to a chamber in the bottom hole assembly, the chamber being sealed from the outside.

8. The well intervention apparatus of claim 7, wherein the chamber is formed in the termination assembly of the bottom hole assembly, and wherein the chamber is sealed from above by the seal around the hose and sealed from below by a second seal.

9. The well intervention apparatus of claim 7, comprising a connector in said chamber for connecting a continuation tube to one of said individual tubes, the continuation tube extending to the at least one tool.

10. The well intervention apparatus of claim 3, wherein the termination assembly is removably connected to the at least one tool.

11. The well intervention apparatus of claim 1, comprising at least two tools at the downhole end portion of the hose, a said individual tube providing a fluid path for fluid communication between outside of the well and a first one of said at least two tools, and a said individual tube providing for fluid communication between outside of the well and a second one of said at least two tools.

12. The well intervention apparatus of claim 1, further comprising at least one second individual tube in the form of an electrical cable.

13. The well intervention apparatus of claim 1, wherein the sealing arrangement further comprises a second seal, a first ring member, and a second ring member; wherein the first ring member is disposed between the wedge members and the second seal, and the second ring member is disposed between the second seal and the seal.

14. A method of well intervention comprising lowering a flexible hose into a well through a stuffing seal which engages around the hose during lowering, at least one tool being provided at a downhole end portion of the hose, and a plurality of individual tubes extending along an inside region of the hose and connecting to the at least one tool, each individual tube providing a fluid path for fluid communication between outside of the well and the at least one tool inside the well, and each individual tube being laterally supported in said inside region such that its lateral movement is restricted; wherein the flexible hose includes a bottom hole assembly disposed at the downhole end portion of the hose, and the bottom hole assembly has a sealing arrangement that includes a seal disposed around the downhole end portion of the hose and a pair of wedge members, each wedge member extending a circumferential distance around the hose, wherein the sealing arrangement is configured so that the wedge members compress the seal into sealing engagement with the hose.

15. The method of claim 14, wherein flexible material is provided in the inside region of the hose to provide said lateral support to the individual tubes.

16. The method of claim 14, comprising carrying out a plurality of operations using the at least one tool.

17. The method of claim 16, comprising carrying out a first of said plurality of operations using a first one of said individual tubes for fluid communication, and carrying out a second of said plurality of operations using a second one of said individual tubes for fluid communication.

18. The method of claim 16, comprising lowering the flexible hose once to perform said plurality of operations using the at least one tool, and then raising the flexible hose.

19. The method of claim 14, wherein the well is a non-subsea well.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Certain preferred embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which:

(2) FIG. 1 is an overview of an intervention system according to the invention, in a side elevation view;

(3) FIG. 2 is a front elevation view of the system of FIG. 1;

(4) FIG. 3 is an elevation view of a bottom hole assembly on the end of an intervention hose;

(5) FIG. 4 is a perspective view of the bottom hole assembly with the tools shown separated;

(6) FIG. 5 is a vertical sectional view on lines D-D of FIG. 3;

(7) FIG. 6 is a horizontal sectional view on lines A-A of FIG. 3;

(8) FIG. 7 is a horizontal sectional view on lines B-B of FIG. 3;

(9) FIG. 8 is a horizontal sectional view on lines C-C of FIG. 3;

(10) FIG. 9 is a perspective view of a well logging tool;

(11) FIG. 10 is a perspective view of a termination assembly;

(12) FIG. 11 is an elevation view of the termination assembly;

(13) FIG. 12 is a vertical sectional view on lines A-A of FIG. 11;

(14) FIG. 13 shows detail “B” indicated in FIG. 12; and

(15) FIG. 14 shows an alternative embodiment of intervention hose.

(16) The drawings are schematic in nature and where cross-sections are shown some features are omitted for simplicity of explanation.

DETAILED DESCRIPTION OF THE INVENTION

(17) FIG. 1 shows an intervention set up for a well head on a fixed offshore platform or a land well. The well head is thus “dry” in the sense that it is not underwater and is either above the sea surface or is on land.

(18) An intervention hose 2 is provided on a drum 4 supported in a drum housing 6 which sits on the ground or a deck. The drum 4 includes a pulling mechanism, which can also provide a back tension function. The pulling mechanism may be of the type used for wire line drums. The drum 4 also includes a spooling mechanism, as is known for coiled tubing intervention reels.

(19) The intervention hose 2 extends from the drum to a guiding sheave (not shown) rotatably supported on a guiding sheave holder 8 (partially shown), where it is deviated from an upwardly inclined direction to a vertical downward direction, towards a well. The intervention hose 2 extends downwardly from the guiding sheave into an intervention stack 10, which consists of a dual stuffing box 12 and a lubricator 14. The dual stuffing box 12 comprises a plurality of stuffing seals which engage in sealing manner around the intervention hose, to allow the hose to be lowered or raised whilst providing an environment below the dual stuffing box 12 which is sealed from the outside.

(20) A blow-out preventer (BOP) 16 is provided below the intervention stack 10, and a shear seal 18 is provided below the BOP. In this embodiment, in which the intervention is being performed on a subsea well, a flanged connection 20 to a riser 22 is provided below the shear seal 18, and the riser 22 extends vertically downwardly from the surface through the sea to a wellhead (not shown). In an alternative embodiment, where the intervention is being performed on a land-based well, the flanged connection 20 is made directly to a wellhead.

(21) FIGS. 3-8 show a bottom hole assembly 24 provided at a downhole end portion of the intervention hose 2. The bottom hole assembly 24 comprises a termination assembly 26 for the intervention hose 2, and a plurality of tools consisting of a well logging tool 28, a high-pressure jetting tool 30, and a drilling tool 32.

(22) The intervention hose 2 comprises a plurality of individual tubes contained in an outer sheath 34, as can be seen in FIG. 10. The individual tubes consist of a pair of electric cables 36, five small-diameter fluid lines 38, a pair of intermediate diameter fluid lines 40, and a large diameter fluid line 42. A central load-bearing metal cable 44 is also provided in the outer sheath 34. Fill material 46 occupies the rest of the inside region of the outer sheath 34, and provides lateral support to the individual tubes to restrict their lateral movement. In an alternative embodiment, the tubes themselves may be sufficiently closely packed such that they are laterally supported to have their lateral movement restricted.

(23) The pair of electric cables 36 communicate with the well logging tool 28, the five small-diameter fluid lines 38 communicate with the jetting tool 30, and the intermediate diameter fluid lines 40 and the large diameter fluid line 42 communicate with the drilling tool 32. This arrangement will be further described with reference to FIGS. 3-8.

(24) A chamber 46 is provided in the termination assembly 26, and in this chamber the individual tubes emerge from the outer sheath 34 of the intervention hose 2. At the upper end of the chamber 46 a sealing arrangement is provided on the outer sheath in order to seal the chamber from the outside. At the lower end of the chamber 46 another sealing arrangement is provided to seal the chamber from the outside. Further details of the sealing arrangements are described later.

(25) The metal cable 44 also emerges from the outer sheath 34 of the intervention hose 2 into the chamber 46 and is secured at its lower end to the termination assembly 26 by an anchor 48. The individual tubes extend downwardly through the chamber 46 to a set of twin ferrule connector assemblies 50 (see FIG. 12). They connect via these assemblies to corresponding individual tubes in a feed-through receptacle 52 in the lower part of the termination assembly 26. The individual tubes in the feed-through receptacle 52 provide continuations of the individual tubes 36, 38, 40 and 42 respectively of the intervention hose, so as to form continuation individual tubes in the feed-through receptacle 52. FIGS. 5 and 12 show continuation individual tubes 38a and 42a in the feed-through receptacle 52 for the individual tubes 38 and 42 of the intervention hose (the continuation individual tubes in the feed-through receptacle 52 for individual tubes 36 and 40 are not shown). The continuation individual tubes in the feed-through receptacle 52 connect via another set of twin ferrule connector assemblies 54 at the interface between the termination assembly 26 and the well logging tool 28, to a set 56 of individual tubes in the well logging tool 28, as indicated by the section A-A shown in FIG. 6. The set 56 of individual tubes thus comprises continuation individual tubes 36b, 38b, 40b and 42b respectively of the individual tubes 36, 38, 40 and 42 contained in the intervention hose 2. The continuation individual tubes 36b corresponding to the pair of electric cables 36 terminate within the well logging tool 28, thereby providing electrical communication between that tool and the surface, via the intervention hose 2 extending to the surface.

(26) The other continuation individual tubes of the set 56 in the well logging tool 28, namely continuation individual tubes 38b, 40b and 42b, pass through the well logging tool 28 to another set of twin ferrule connector assemblies 58 at the interface between the well logging tool 28 and the high-pressure jetting tool 30. The twin ferrule connector assemblies 58 form a connection with a set 60 of individual tubes in the jetting tool 30, these individual tubes consisting of continuation individual tubes 38c, 40c and 42c, which provide further continuations respectively of the individual tubes 38, 40 and 42 contained in the intervention hose 2. The continuation individual tubes 38c, 40c and 42c are shown in the section 8-8 of FIG. 7, The continuation individual tubes 38c corresponding to the five small-diameter fluid lines 38 of the intervention hose 2 terminate at the jetting tool 30 via jetting nozzles 62. Thus, fluid communication is provided between the jetting tool 30 and the surface, via the intervention hose 2 extending to the surface.

(27) The other continuation individual tubes of the set 60 in the jetting tool 30, namely tubes 40c and 42c, pass downwardly along the length of the tool to a further set of twin ferrule connector assemblies 64 at the interface between the jetting tool 30 and the drilling tool 32. The twin ferrule connector assemblies 64 form a connection with a set 66 of individual tubes in the drilling tool 32, this set 66 consisting of continuation individual tubes 40d and 42d, which provide further continuations respectively of the individual tubes 40 and 42 contained in the intervention hose 2. The continuation individual tubes 40d and 42d are shown in the section C-C of FIG. 8. The continuation individual tubes 40d and 42d terminate in the drilling tool 32, thereby providing fluid communication between the drilling tool 32 and the surface, via the intervention hose 2 extending to the surface. In this embodiment, the continuation individual tubes 40d supply hydraulic fluid under pressure, and the continuation individual tube 42d provides a drain line.

(28) The drilling tool 32 is removably connected to the jetting tool 30. If it is desired to modify the bottom hole assembly 24 by omission of the drilling tool 32, it can be disconnected and the continuation individual tubes 40c and 42c could be terminated by appropriate plugs, either at the interface between the jetting tool 30 and the drilling tool 32, or the interface between the well logging tool 28 and the jetting tool 30.

(29) Similarly, the jetting tool 30 is removably connected to the well logging tool 28. Therefore, if it is desired to modify the bottom hole assembly 24 by omission of the jetting tool 30 and the drilling tool 32, the jetting tool 30 may be disconnected from the well logging tool 28. The continuation individual tubes 38b, 40b and 42b could be terminated by appropriate plugs, either at the interface between the well logging tool 28 and the jetting tool 30, or the interface between the termination assembly 26 and the well logging tool 28.

(30) In this embodiment twin ferrule connector assemblies are provided for all the individual tubes in the termination assembly 26, at the interface between the termination assembly 26 and the well logging tool 28, at the interface between the well logging tool 28 and the jetting tool 30, and at the interface between the jetting tool 30 and the drilling tool 32. However, in alternative embodiments an individual tube may extend continuously from the intervention hose 2 through the termination assembly 26 to a tool, without having to form a connection via one or more twin ferrule connector assemblies.

(31) FIG. 9 shows the lower portions of the set of twin ferrule connector assemblies 54 at the interface between the termination assembly 26 and the well logging tool 28. A pair of lower portions 68 belongs to the connector assemblies which connect the individual tubes in the feed-through receptacle 52 which correspond to the individual tubes 36 in the intervention hose 2 to the individual tubes 36b in the well logging tool 28. Five lower portions 70 belong to the connector assemblies which connected the individual tubes 38a in the feed-through receptacle 52 which correspond to the individual tubes 38 in the intervention hose 2 to the individual tubes 38b in the well logging tool 28. A pair of lower portions 72 belongs to the connector assemblies which connect the individual tubes in the feed-through receptacle 52 which correspond to the individual tubes 40 in the intervention hose 2 to the individual tubes 40b in the well logging tool 28. A lower portion 74 belongs to the connector assembly which connects the individual tube 42a in the feed-through receptacle 52 which corresponds to the individual tube 42 in the intervention hose 2 to the individual tube 42b in the well logging tool 28. Steering pins 76 project upwardly at the upper face of the well logging tool 28 to assist alignment when it is connected to the termination assembly 26.

(32) FIGS. 11-13 show further details of the termination assembly 26. A generally conical upper sleeve 84 is bolted to the feed-through receptacle 52 and defines internally the chamber 46. The upper sleeve 84 has an upper portion 88 which generally surrounds the outer sheath 34 of the intervention hose 2 and is closed by a closing plate 86 which is bolted to the upper portion. The closing plate 86 has a downwardly facing annular surface extending around the outer sheath 34. The upper portion 88 of the upper sleeve 84 has a conical recess with a diameter narrowing in the downward direction. At the base of the conical recess an annularly extending shoulder 90 faces upwardly.

(33) A sealing arrangement is provided on the outer sheath in order to seal the chamber from the outside. The sealing arrangement comprises a pair of O-rings 78 and a pair of ring members 80 which extend round the outer sheath 34 of the intervention hose 2, as seen in further detail in FIG. 13. The ring members 80 have a substantially square cross-section as viewed in the radial direction of the ring members. An upper one of the ring members 80 engages an upper surface of an upper one of the O-rings 78, and a lower one of the ring members 80 engages an upper surface of a lower one of the O-rings 78. A pair of wedge members 82, each extending 180° circumferentially of the intervention hose 2, engages the outer sheath 34 and each wedge member 82 has a respective lower axial end face 83 for engagement with the upper one of the pair of ring members 80. During assembly, the wedge members 82 are placed around the outer sheath 34 and are urged downwardly by engagement of the closing plate 86 during bolting of that plate to the upper portion 88 of the upper sleeve 84. As a result, the lower axial end faces 83 of the wedge members 82 engage the upper ring member 80 and urge it downwardly. As the upper ring member 80 is urged downwardly, it pushes downwardly on the upper O-ring 78, which in turn pushes downwardly on the lower ring member 80, which in turn pushes downwardly on the lower O-ring 78. Since the lower O-ring 78 sits on the shoulder 90 of the upper portion 88 of the upper sleeve 84, it cannot move downwardly. The consequence therefore of urging the wedge members 82 downwardly is to compress the upper and lower O-rings 78 and create a seal between the outer sheath 34 of the intervention hose 2 and the inside wall of the conical recess of the upper portion 88 of the upper sleeve 84. Thus, the chamber 46 is sealed at its upper end from the outside.

(34) At the lower end of the chamber 46 another sealing arrangement is provided to seal the chamber from the outside. The upper sleeve 84 terminates in a lower skirt 91, where it is bolted to the feed-through receptacle 52. A top portion of the feed-through receptacle is provided with a pair of O-rings 92, which provide the sealing arrangement at the lower end of the chamber 46 by sealing between the feed-through receptacle 52 and the lower skirt 91 of the upper sleeve 84 of the termination assembly 26.

(35) The termination assembly 26 is connected in removable and sealed manner to the well logging tool 28. A pair of O-rings 94 is provided around the radially outer surface of a lower portion of the feed-through receptacle 52, and each O-ring 94 engages with a radially inner surface of an upper portion of the well logging tool 28. A connecting sleeve 96 on the lower portion of the feed-through receptacle 52 is formed with an internal thread 98 which mates with an external thread on an upper portion of the well logging tool (not shown). During assembly, once the respective twin ferrule connector assemblies at the interface between the termination assembly 26 and the well logging tool 28 are aligned and connected up, the connecting sleeve 96 is rotated relative to the lower portion of the feed-through receptacle 52 to cause the well logging tool 28 to advance upwardly without rotation relative to the termination assembly 26. Once the well logging tool and the termination assembly 26 are tightly engaged, the connecting sleeve 96 is locked in place using screws 98.

(36) In a similar manner to the connection between the termination assembly 26 and the well logging tool 28, the well logging tool 28 is connected in a removable and sealed manner to the jetting tool 30, and the jetting tool 30 is connected in a removable and sealed manner to the drilling tool 32.

(37) FIG. 14 shows another embodiment of an intervention hose 2. In this embodiment there is provided radially inwardly of the outer sheath 34 a wire armor tube 100, which serves to provide the hose with tensile strength and to protect the internal individual tubes. An inner sheath 102 is provided radially inwardly of the wire armor tube 100, and inside the inner sheath 102 individual tubes are provided for electrical and fluid communication. Electrical cables 36 are provided at the core of the hose and are surrounded by binding tape 106. Three different diameter individual tubes 108 are provided for fluid communication, and filler members 110 are provided in some of the voids between the electrical cables 36, and also between the tubes 108. The filler members 110 provide a flexible material to provide lateral support to the individual tubes. The voids are further occupied by filler material 112 in the form of an injected resin or plastic, further assisting with lateral support.