CONDUCTOR ASSEMBLY AND METHODS

Abstract

A conductor assembly comprising a conductor of an offshore platform and a guide surrounding the conductor. The guide extending from an upper end to a lower end and having a main portion therebetween, a stabilising body defining a bore extending therethrough, the conductor extending through the bore of the stabilising body, the stabilising body provided between the conductor and the guide optionally the stabilising body comprising an inner body and an outer body. In this way, the conductor is allowed to move vertically within the guide with the only moving surfaces in contact being an outer surface of the inner body and the inner surface of the outer body, thus mitigating or eliminating abrasion of the conductor and/or guide.

Claims

1. A conductor assembly comprising: a conductor of an offshore platform; a guide surrounding the conductor, the guide extending from an upper end to a lower end and having a main portion therebetween; a stabilising body defining a bore extending therethrough; the conductor extending through the bore of the stabilising body; the stabilising body provided between the conductor and the guide; the stabilising body comprising an inner body and an outer body.

2. The conductor assembly of claim 1, wherein the stabilising body comprises one or more elastic material components, such as polyurethane, optionally formed from a polyol and an isocyanate or diisocyanate.

3. The conductor assembly of claim 1, wherein the outer surface of the inner body and the inner surface of the outer body are unbonded and thus moveable with respect to one another.

4. The conductor assembly of claim 1, wherein the inner body is bonded to the surface of the conductor and an outer body is bonded to the inner surface of the guide.

5. The conductor assembly of claim 1, wherein there is a space defined between the outer surface of inner body and inner surface of the outer body.

6. The conductor assembly of claim 1, wherein the dimensions of the space defined between the inner and outer stabilising bodies is selected to take account of the changing dimensions of said stabilising bodies over time, due to environmental and/or process conditions.

7. The conductor assembly as claimed in claim 5, wherein the space is a substantially vertical circumferential gap between said first and second stabilising bodies, optionally defined along the full height of the outer stabilising body.

8. The conductor assembly of claim 5, wherein the outer diameter of the inner body is smaller than the inner diameter of the outer body.

9. The conductor assembly of claim 1, wherein at least one of the inner and outer bodies fill less than 50% of the cross-section of the annulus defined by the conductor and the guide.

10. The conductor assembly of claim 1, wherein the stabilising body comprises an upper end, a cylindrical main portion, a lower end and at least one of the upper and lower ends has a radially extending portion having a diameter greater than the main cylindrical portion.

11. The conductor assembly of claim 10, wherein the outer stabilising body comprises the radially extending portion, preferably at the upper end thereof.

12. The conductor assembly of claim 1, wherein the stabilising body has a tail section extending beyond at least one end of the guide.

13. The conductor assembly of claim 1, wherein the stabilising body comprises at least one sensor device optionally adapted to collect data related to the integrity of the assembly.

14. The conductor assembly of claim 13, wherein at least one sensor device comprises at least one of a material inspection sensor, such as an electromagnetic acoustic transducer, and a motion sensor, such as an accelerometer.

15. The conductor assembly of claim 13, wherein the at least one sensor device comprises one or more wireless transmitters, such as an ultrasonic transmitter, or an acoustic, Radio Frequency or Free-Space Optical connection.

16. The conductor assembly of claim 1, wherein the inner body comprises a first material component and the outer body comprises a second material component, the first and second material components having different mechanical properties, such as hardness, elongation at break, tensile strength, compressive strength, compression set, elastic modulus, abrasion resistance, water uptake and/or fatigue life.

17. The conductor assembly of claim 1, wherein the inner and/or outer stabilising bodies have one or more of the following mechanical properties, upon installation: hardness in the range of 60-90 on the Shore A scale; tensile strength of 8-28 N/mm.sup.2; elongation at break of 270-570%; tear propagation resistance of 9-68 N/mm{circumflex over ( )}.sup.2.

18. The conductor assembly of claim 1, wherein the inner body comprises two or more parts and the outer body comprises two or more parts.

19. The conductor assembly of claim 1, wherein the conductor comprises appurtenance, such as one or more connectors or thrust collars, and wherein the outer diameter of the inner stabilising body is equal or greater than the maximum outer diameter of the said appurtenance along its length, and wherein the inner diameter of the outer stabilising body is larger than the outer diameter of the inner stabilising body.

20. The conductor assembly of claim 1, wherein the stabilising body is pre-cast in at least two parts, optionally prior to the installation of the conductor and/or guide.

21. The conductor assembly of claim 1, wherein the stabilising body is cast in situ.

22. A method of stabilising a conductor in a guide in an offshore system, the guide provided around the conductor, thereby defining an annulus between the guide and the conductor, the guide extending from an upper end to a lower end, the method comprising the steps of: providing a first mould at the lower end of the guide, with a base diameter smaller than the outer diameter of the lower end of the guide; introducing a stabilising compound in a liquid form through the annulus towards mould; allowing the stabilising compound to set and form a solid inner stabilising body at least partially between the conductor and the guide; installing a second mould onto the conductor, the second mould having a base diameter equal to or larger than the diameter of the lower end of the guide; introducing a stabilising compound in a liquid form through the annulus towards the second mould; allowing the stabilising compound to set and form a solid outer stabilising body at least partially between the conductor and the guide.

23. The method of claim 22, wherein the second mould has a wider base diameter than the outer diameter of the lower end of the guide.

24. The method of claim 22, wherein the first mould has walls extending through the guide and, optionally, beyond the upper end thereof.

25. The method of claim 22, wherein the first mould is removed prior to the introduction of the second mould.

26. The method of claim 22, wherein the inner stabilising body is bonded to the outer surface of the conductor and the outer stabilising body is bonded to the inner surface of the guide.

27. The method of claim 26, including at least one of the following steps: assessing the bond between the inner stabilising body and the conductor using one or more measurements taken circumferentially and/or longitudinally based on an ultrasonic reflection; assessing the bond between the outer stabilising body and the guide using one or more measurements taken circumferentially and/or longitudinally based on an ultrasonic reflection.

28. The conductor assembly of claim 1, wherein the guide is located topside.

29. The conductor assembly of claim 15, further comprising an inspection instrument, the inspection instrument comprising at least one of a transmitter and a receiver, and configured to communicate with the one or more transmitters in the at least one sensor device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0131] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

[0132] FIG. 1a shows a side view of a prior art arrangement of a conductor pipe in a conductor guide;

[0133] FIG. 1b shows a top view of the prior art arrangement of FIG. 1; FIG. 1c shows a top view of the prior art arrangement of FIG. 1 wherein a fault has occurred;

[0134] FIG. 2 shows a side perspective view of an embodiment of the present invention;

[0135] FIGS. 3a-3c are sequential side sectional views of the FIG. 2 apparatus;

[0136] FIGS. 4a-4b show a side perspective view of an embodiment of the present invention;

[0137] FIGS. 5a-5c are sequential side sectional views of the FIG. 4a-4b apparatus;

[0138] FIG. 6a shows a side view of a prior art arrangement of a conductor pipe comprising thrust collars in a conductor guide;

[0139] FIG. 6b shows a side perspective view of an embodiment of the present invention;

[0140] FIGS. 6c-6d are sequential side sectional views of the FIG. 6b apparatus;

[0141] FIGS. 7a-7b show a perspective side sectional views of an embodiment of the present invention;

[0142] FIGS. 8a-8h are sequential side sectional views of the FIG. 7a-7b apparatus;

[0143] FIGS. 9a-9c are sequential side views of an embodiment of the present invention;

[0144] FIG. 10a is a side view of a further embodiments of the present invention;

[0145] FIG. 10b is a sectional view through line A-A of FIG. 10a; and,

[0146] FIG. 10c is a perspective view of the FIG. 10a embodiment.

DETAILED DESCRIPTION

[0147] FIG. 1a shows a typical set up of a conductor pipe 10 run through a conductor guide 20. The conductor pipe 10 defines a longitudinal dimension along the length thereof, denoted as the y-axis. As follows, references to the length of the conductor pipe 10 or the length of the conductor guide 20 should be understood as substantially along the direction defined by the y-axis.

[0148] The conductor guide 20 comprises a substantially cylindrical main portion 21 whose diameter is substantially constant along the length thereof. The guide 20 further comprises an upper end 22 and a lower end 23. The upper end 22 and lower end 23 are defined as the cross-sections at the respective ends of the guide 20. The guide 20 further comprises a substantially conical portion 24 extending between the main portion 21 and the upper end 22. The cross-sectional diameter of the conical portion 24 increases along the length of the guide 20, towards the upper end 22. Consequently, the diameter of the upper end 22 is larger than the average diameter of the main portion 21. The dashed line shows the central position of a centraliser 30 in the annulus 11 defined between the conductor 10 and the guide 20. FIG. 1b is a top down view of the set-up of FIG. 1a. The centraliser 30 comprises four contact elements 31a-31d which are welded/bolted to the guide 20. In FIG. 1b, the centraliser is operational and thus stabilises the conductor 10 in the guide 20.

[0149] Over time, fatigue of the guide due to cyclical loading of waves and currents may lead to failure of the welding/bolting of one or more of the contact elements 31a-31d. FIG. 1c is another top view of the set up in FIG. 1a, but in which case a failure of welding/bolting of the contact elements 31b-31d has occurred and the stability of the conductor 10 within the guide 20 is compromised.

[0150] An embodiment of an apparatus and method of stabilising a conductor 10 in a guide 20, for example following a centraliser failure, according to the present invention, is shown in FIGS. 2-3c.

[0151] The size of the annulus 11 in FIG. 1a can be determined and a stabilising body of desired dimensions may be pre-cast to substantially fit the annulus 11. FIG. 2 shows an elastic polyurethane stabilising body 6 pre-cast in two parts 6a, 6b. The stabilising body comprises sensor devices 50 within the main portion 61 thereof. The sensor devices 50 are comprise an EMAT sensor and an accelerometer.

[0152] The stabilising body 6 comprises a substantially cylindrical main portion 61 whose diameter is substantially constant along the length of the stabilising body 6. The stabilising body 6 further comprises a first end 62 and a second end 63, both ends defined as outermost cross-sections of the stabilising body 6. The stabilising body 6 further comprises a conical portion 64 extending between the main portion 61 and the first end 62. The diameter of the conical portion 64 increases along the length of the conical portion 64, towards the first end 62. Consequently, the diameter of the first end 62 is larger than the average diameter of the main portion 61. The stabilising body further comprises an inverted conical portion 65 extending between the main portion 61 and the second end 63. The diameter of the inverted conical portion 65 proximal to the main portion 61 is substantially larger than the main diameter of the main portion 61, and decreases along the length of the inverted conical portion 65, towards the second end 63. Thus, the inverted conical portion 65 forms an arrowlike shape pointing towards the second end 63. Finally, the stabilising body 6 comprises an annulus 66 extending through the length thereof, from the first end 62 to the second end 63.

[0153] The dimensions of the stabilising body 6 are substantially matched to the dimensions of the system in which it is used, such as that shown in FIG. 1a. The diameter of the main portion 61 and conical portion 64 of the stabilising body 6 substantially matches the diameter of the main portion 21 and the conical portion 24 of the guide 20. The diameter of the annulus 66 of the stabilising body 6 is marginally larger than the diameter of the conductor 10. Thus, the stabilising body 6 substantially fits in the annulus 11 between the conductor 10 and the guide 20. The maximum diameter of the inverted conical section is larger than the diameter of the lower end 23 of the guide 20, such as to secure the stabilising body 6 in the annulus 11.

[0154] FIGS. 3a-3c show the stabilising body in use in the set-up of FIG. 1a, located subsea. As shown in FIG. 3a, the two parts 6a, 6b meet around the conductor pipe to form the stabilising body 6 and pushed into the annulus 11. While being pushed through the annulus 11, the elastic inverted conical section 65 is deformed, thereby allowing for the stabilising body 6 to be pushed further through the annulus, as shown in FIG. 3b. The inverted conical section 65 returns substantially to its original shape as it emerges beyond the lower end 23, securing the stabilising body 6 in place, as depicted in FIG. 3c.

[0155] An advantage of some embodiments of the present invention is that the stabilising body 6 is pre-cast prior to use, thus being suitable for use in both topside and subsea locations.

[0156] A further advantage of some embodiments of the present invention is that the elasticity and relatively light weight of the stabilising body 6 allow for an easy and safe installation thereof.

[0157] A further advantage of some embodiments of the present invention is that the stabilising body 6 is in form of a stress-absorbing elastic solid and substantially fills the annulus between the conductor 10 and the guide 20. Thus, stabilising body 6 allows for making use of the full stabilising capability of the guide 20, while avoiding point-stress loads and dampening vibration,

[0158] A further advantage of some embodiments of the present invention is that the stabilising body 6 is not bonded to the surface of the conductor 10, thereby allowing for vertical movement of the conductor 10 within the guide 20.

[0159] A further advantage of some embodiments of the present invention is that the durability of the elastic polyurethane and its resistance to corrosion eliminates the need of maintenance of the stabilising body 3 after installation.

[0160] A further advantage of some embodiments of the present invention is that the substantially conical portion of the stabilising body 3 prevents the stabilising body 3 from moving down the guide 20, while the flange-shaped radially extending portion below thereof prevents it from moving up the guide 20. Thus, the stabilising body 3 secures itself in the guide 20, eliminating the need for a dedicated securing mechanism.

[0161] A further advantage of some embodiments of the present invention is that the sensor devices 50a, 50b provided as part of the stabilising body 6 allow for monitoring local conditions of the conductor 10 and/or the guide 20.

[0162] A further embodiment of an apparatus and method of stabilising the conductor 10 in the guide 20, according to the present invention, is shown in FIGS. 4a-5c.

[0163] FIG. 4a shows a stabilising body 7 pre-cast in two parts 7a, 7b from a stabilising compound 2. The stabilising body comprises sensor devices 50 within the main portion 61 thereof. The sensor devices 50 comprise an EMAT sensor and an accelerometer.

[0164] The stabilising body 7 comprises a substantially cylindrical main portion 71, a first end 72 and a second end 73, both ends defined as outermost cross-sections of the stabilising body 7. The stabilising body 7 further comprises a conical portion 74 extending between the main portion 71 and the first end 72. The diameter of the conical portion 74 increases along the length of the conical portion 74, towards the first end 72. Consequently, the diameter of the first end 72 is larger than the average diameter of the main portion 71.

[0165] The stabilising body 7 further comprises two removable threaded bars 81 inserted thereto through the first end 72 thereof, one into each part 7a, 7b thereof. Each threaded bar 81 comprises a handle 80 at an end thereof, opposite to the end inserted into the stabilising body 7. The stabilising body 7 further defines two sockets 77, one in each part 7a, 7b thereof. Each socket 77 is located within the main portion 71, proximally to the second end 73. Each socket 77 defines a threaded bore 78, dimensions of which match that of the threaded bar 81.

[0166] A retainer block 82 is shown in FIG. 4b with dimensions matching the dimensions of the socket 77. The retainer block 82 defines a threaded bore 83 extending through two opposite ends thereof. The dimensions of the threaded bore 83 match the dimensions of the threaded bore 78 and the threaded bar 81.

[0167] FIGS. 5a-5c show the stabilising body in use in the set-up of FIG. 1a.

[0168] As shown in FIG. 5a, the two parts 7a, 7b meet around the conductor 10 to form the stabilising body 7 and are inserted into the annulus 11 between the conductor 10 and the guide 20, using the handles 80. The dimensions of the stabilising body 7 are substantially matched to the dimensions of the annulus 11. The diameter of the main portion 71 and conical portion 74 of the stabilising body 7 substantially matches the diameter of the main portion 21 and the conical portion 24 of the guide 20. The diameter of the annulus 76 of the stabilising body 7 is marginally larger than the diameter of the conductor 10. Thus, the stabilising body 7 substantially fits in the annulus 11 between the conductor 10 and the guide 20. The main portion 71 of the stabilising body 7 is longer than the main portion 21 of the guide 20. Thus, a portion of the stabilising body 7 proximal to the second end 73 thereof extends through and beyond the lower end 23 of the guide 23. The portion of the stabilising body 7 extending beyond the lower end 23 defines the sockets 77.

[0169] As shown in FIG. 5b, once inserted into the annulus 11, the stabilising body is secured in place by means of the retainer blocks 82, which are inserted into the sockets 77. The bore 83 of each retaining block 77 aligns with the respective bore 78 in the stabilising body 7. The handles 80 are then used to remove the respective rods 81 from the first end 72 of the stabilising body 7 and insert them into the respective threaded bores 83, through the retaining blocks 82, and into the threaded bores 78. Thus, the threaded bars 81 holding the retainer blocks 82 in the sockets 77 prevent movement of the stabilising body 7 through the guide 20 in the directions towards the upper end 22, thereby securing the stabilising body 7 in the annulus 11.

[0170] An advantage of some embodiments of the present invention is that the stabilising body 7 may be easily installed and secured in place by means of the threaded bars 81.

[0171] A further embodiment of an apparatus and method for stabilising the conductor 10 in the guide 20, according to the present invention, is shown in FIGS. 6a-6d. In this example, the offshore system is that shown in FIG. 1a, but additionally comprising thrust collars 12 on the conductor 10, as depicted in FIG. 6a.

[0172] FIG. 6b shows a stabilising body comprising an inner body 9, formed in two parts 9a, 9b out of a stabilising compound 2a, and an outer body 19 formed in two parts 19a, 19b out of a stabilising compound 2b. The outer body 19 can be characterised by a larger degree of elasticity compared with the inner body 9. Alternatively, the inner and outer bodies 9, 19 may be cast of the same material, thereby having the same degree of elasticity.

[0173] The inner body 9 is substantially cylindrical and defines a bore 96 extending therethrough.

[0174] The outer body 19 comprises a substantially cylindrical main portion 191, a first end 192 and a second end 193, both ends defined as outermost cross-sections of the outer body 19. The outer body 19 further comprises a substantially conical portion 194 extending between the main portion 191 and the first end 192. The diameter of the conical portion 194 increases along the length of the conical portion 194, towards the first end 192.

[0175] Consequently, the diameter of the first end 192 is larger than the average diameter of the main portion 191. The outer body 19 defines a bore 196 extending therethrough between the first end 192 and the second end 193. The bore 196 comprises a substantially cylindrical portion and an inverted conical portion, the latter forming a lip 199 around the inner surface of the bore 196, proximal to the second end 193. The lip 199 is directed radially inwardly towards the conductor 10.

[0176] The diameter of the cylindrical portion of the bore 196 is substantially the same as the diameter of the inner body 9. Thus, the inner body 9 substantially fits in the bore 196 of the outer body 196.

[0177] In FIG. 6c, parts 9a, 9b are inserted into the annulus 11, between the thrust collars 12, to form the inner stabilising body 9. The diameter of the inner stabilising body 9 substantially matches the diameter of the thrust collars 12, and the inner annulus of the stabilising body 9 is marginally larger than that of the conductor 10.

[0178] The parts 10a, 10b are then inserted into the annulus 11, forming the outer stabilising body 19, as shown in FIG. 6c. The elasticity of the outer stabilising body 19 allows for the lip 199 to deform thereby allowing for insertion of the outer body 19 into the annulus 11. Once the outer body 19 is in place, the lip 199 returns substantially to its initial shape, locking the outer body 19 against the thrust collar 12 proximal to the lower end 23 of the guide 20. Thus, the lip 199 secures the outer body 19 in the annulus 11, with the inner body 9 therein, as shown in FIG. 6d.

[0179] An advantage of some embodiments of the present invention is that the stabilising body 9 may be easily installed on conductors comprising thrust collars 12.

[0180] A further embodiment of an apparatus and method for stabilising the conductor 10 in the guide 20, particularly suited to a topside arrangement (above the surface of the sea), according to the present invention, is shown in FIGS. 7a-8h.

[0181] FIGS. 7a and 7b show the set-up of FIG. 1a also comprising two semi-moulds 40a, 40b. The semi-moulds 40a, 40b can be assembled into a single mould 40 around the conductor 10 near the lower end 23 of the guide 20 as depicted in FIG. 1e. The mould 40 can be installed onto the conductor 10 via rope access and held in place by a retaining member 42 in the form of a rachet mechanism 42.

[0182] As shown in FIG. 8a, part of the conductor 10, below the centraliser 30, is painted with a demoulding agent 1. The demoulding agent 1 is provided to ensure that the surface of the conductor 10 is prevented from bonding to the surface of a stabilising body later cast in the annulus 11. The demoulding agent 1 is similarly applied to the inner surface of the mould 40, as shown in FIG. 8b. The semi-moulds 40a, 40b are formed into a single mould 40 around the conductor 10 near the lower end 23 of the guide 20 as depicted in FIG. 8c.

[0183] A stabilising compound 2, such as an elastic polyurethane, initially in a flowable state, such as a liquid state, is then poured into the mould 40 in a quantity sufficient to fill the mould 40, for example to fill a portion of the guide 20 up to a level below the centraliser 30, as shown in FIG. 8d. Subsequently, the stabilising compound 2 sets into an elastic solid which forms the bottom section of a stabilising body 3. For example, based on a temperature of 20 degrees centigrade, the stabilising compound 2 will gel after one hour and be fully cured after 24 hours. Once the stabilising compound gels, and before it fully cures, the centraliser 30 is removed from the annulus 11 and the mould 40 may be removed.

[0184] Demoulding agent 1 is then applied to a portion of the conductor 10 adjacent to the already formed part of the stabilising body 3, as shown in FIG. 8e. A further amount of the stabilising compound 2 is poured into the annulus 11 to substantially fill up the main portion 21 of the guide 20, and two sensor devices 50a, 50b are inserted therein. The first sensor device 50a is an EMAT sensor. The second sensor device 50b is an accelerometer. The sensor devices are capable of wireless communication with both onshore and offshore locations via an inspection instrument (not shown). Once again, the stabilising compound 2 gels forming the middle section of the stabilising body 3. This is shown in FIG. 8f.

[0185] A further portion of the conductor 10, adjacent to the already formed part of the stabilising body 3, is coated with demoulding agent 1, as shown in FIG. 8g, and then the remaining part of the annulus 11 is filled with the stabilising compound 2, which is left to set and the top section of the stabilising body 3 is formed. The final full stabilising body 3, comprising sensor devices 50a, 50b, is shown in FIG. 8h.

[0186] An advantage of some embodiments of the present invention is that, the top section of the stabilising body 3 is cast after the middle section thereof is already gelled, thereby allowing to confirm that there are no issues with the middle section, before casting the top section of the stabilising body. The portion of the system where the middle section is located, i.e. defined by the substantially cylindrical main-portion part of the guide, is normally subject to the most lateral loading during the lifetime of the system.

[0187] As shown in FIG. 8h, the stabilising body 3 is shaped and sized to substantially fit in the annulus between the conductor 10 and the guide 20, thereby comprising a conical portion proximally to the upper end 22 of the guide 20 and, additionally, comprises a flange-shaped radially extending portion below the lower end 23 of the guide 20.

[0188] A further advantage of some embodiments of the present invention is that the stabilising body 3 is formed in situ rather than pre-cast to size, thus its dimensions may be matched precisely with the dimensions of the annulus and scaled or adapted to fit the dimensions of any system.

[0189] In another example of the present invention, it may not be desirable to remove the centraliser 30 from the annulus 11. The centraliser 30 is left in the annulus 11, and the stabilising body 3 is cast with the centraliser 30 therein. The centraliser 30 secures the stabilising body 3 onto the conductor 10. Thus, the radially extending section of the stabilising body 3, below the lower end of the guide 20, is reduced in size or eliminated. In this example, if all welds/bolts of the centraliser fail then the demoulding agent may be applied to the guide 20 rather than to the conductor 10. The surface of the stabilising body 3 is thus bonded onto the outer surface of the conductor 10, but not to the inner surface of the guide 20, and the centraliser is not welded/bolted to the guide and. Thus, vertical motion of the conductor 10 in the guide 20 is still permitted.

[0190] A further advantage of some embodiments of the present invention is that the complexity of the method is minimised as it does not require the removal of the pre-existing centraliser.

[0191] A similar apparatus and method may be applied to a set up exemplified in FIG. 1a further comprising at least one thrust collar.

[0192] FIG. 9a-9c illustrates another example of the present invention, wherein the stabilising body 3 is cast in two parts, an inner stabilising body 3a and an outer stabilising body 3b. The casting of the inner and outer body may be done, for example, by means of separate moulds, an inner mould 41 and an outer mould 42. As shown in FIG. 9b, the inner mould 41 is installed onto the conductor 10, extending to a level below the lower end 23 of the guide 20 and proximally thereto. The inner mould 41 has a base of a smaller cross-sectional diameter than that of the main portion 21 of the guide 20, and a wall extending through the guide 21 and beyond the upper end 22 thereof. The inner mould 41 is coated with a demoulding agent (not shown) and then a stabilising compound is introduced therein.

[0193] One or more sensor devices 50 are inserted into the stabilising compound. With no demoulding agent applied to the surface of the conductor 10, the stabilising compound sets and forms stabilising body 3a that is bonded to the surface of the conductor 10. Mould 41 is uninstalled once the stabilisation compound has cured. The outer mould 42, with inner surface coated with a demoulding agent, is then installed onto the conductor 10 as shown in FIG. 9c. The outer surface of the stabilising body 3a is also coated with the demoulding agent. A second stabilising compound is introduced therein, normally in a three-step process as that depicted in FIGS. 8a-8h. With no demoulding agent applied to the inner surface of the guide 20, the second stabilising compound sets and forms the outer stabilising body 3b that is bonded to the surface of the guide 20. Once the stabilising bodies 3a, 3b are formed, the mould 42 is uninstalled.

[0194] A further advantage of some embodiments of the present invention is that the inner and outer stabilising bodies 3a, 3b are bonded to the surfaces of the conductor 10 and guide 20, respectively. The lack of gaps between the surface of the conductor 10 and the stabilising body 3a, and similarly, between that of the guide 20 and the stabilising body 3b means that the, risk of crevice corrosion thereon is eliminated. Furthermore, the inner and outer stabilising bodies 3a, 3b are not bonded to one another. Thus, the conductor 10 is allowed to move vertically within the guide 20 with the only moving surfaces in contact being the outer surface of the inner body 3a and the inner surface of the outer body 3b. As a result of that, abrasion of the surface of the conductor 10 and/or guide 20 due to their relative motion would be eliminated, or at least substantially reduced.

[0195] FIGS. 10a-c show a further embodiment where an inner stabilising body 3a and an outer stabilising body 3b are provided between a guide 20 and a conductor 10, in a similar way as the FIG. 9 embodiment.