OPTICAL FIBRE SPOOL

Abstract

A spool of optical fibre comprises a spool axis and a length of optical fibre wound around the spool axis to form a plurality of wrap segments arranged axially along the spool axis, wherein adjacent wrap segments partially overlap in the axial direction. Each wrap segment comprises a first wrap layer wound in a first axial direction over a first axial distance, and a second wrap layer wound over the first wrap layer in a reverse second axial direction over a second axial distance greater than the first axial distance, the optical fibre extending from the second wrap layer of one wrap segment to the first wrap layer of an adjacent wrap segment. The spool may be mounted in a device such that the optical fibre can be despooled and deployed from the device.

Claims

1. A spool of optical fibre for mounting in a device such that the optical fibre can be despooled and deployed from the device, the spool comprising: a spool axis; a length of optical fibre wound around the spool axis to form a plurality of wrap segments arranged axially along the spool axis, wherein adjacent wrap segments partially overlap in the axial direction, wherein each wrap segment comprises a first wrap layer wound in a first axial direction over a first axial distance, and a second wrap layer wound over the first wrap layer in a reverse second axial direction over a second axial distance greater than the first axial distance, the optical fibre extending from the second wrap layer of one wrap segment to the first wrap layer of an adjacent wrap segment.

2. The spool according to claim 1, wherein during despooling the wrap segments are each sequentially depleted, one after the other, in a depleting direction axially along the spool axis such that the axial length of the spool reduces in the depleting direction.

3. (canceled)

4. The spool according to claim 1, wherein the additional axial distance covered by the second wrap layer in each wrap segment provides an axial spacing of the adjacent wrap segment.

5. The spool according to claim 1, wherein a portion of the second wrap layer which extends axially beyond the first wrap layer provides support to the first wrap layer.

6. The spool according to claim 1, wherein a transition of the optical fibre from the first wrap layer to the second wrap layer in one or more wrap segments is provided with a change in winding pitch.

7. The spool according to claim 6, wherein at least one of the winding pitch becomes shallower once transitioned into the second wrap layer, and the transition of the optical fibre from the first wrap layer into the second wrap layer is provided with a change from a closed winding pitch to an open winding pitch.

8. (canceled)

9. The spool according to claim 1, wherein at least one of the first wrap layer of one or more wrap segments comprises a uniform winding pitch, and wherein the second wrap layer of one or more wrap segments comprises a varying winding pitch.

10. (canceled)

11. The spool according to claim 9, wherein a first axial portion of the second wrap layer of one or more wrap segments comprises a first winding pitch and a second axial portion of the second wrap layer comprises a second winding pitch.

12. The spool according to claim 11, wherein at least one of the first winding pitch is shallower than the second winding pitch, and the first winding pitch is an open winding pitch and the second winding pitch is a closed winding pitch.

13. (canceled)

14. The spool according to claim 11, wherein the first axial portion extends over the axial extent of the underlying first wrap layer, and the second axial portion extends over the additional axial distance covered by the second wrap layer.

15. The spool according to claim 1, wherein at least two of the plurality of wrap segments define a common outer maximum diameter.

16. The spool according to claim 1, wherein at least a portion of one or more of the wrap segments defines a tapered region relative to the spool axis.

17. The spool according to claim 16, wherein the first axial direction of winding of the first layer of each wrap segment is in an upslope direction of a taper.

18. The spool according to claim 1, comprising a bobbin upon which the optical fibre is wound, wherein the bobbin defines a bobbin axis and a winding surface upon which winding surface the optical fibre is wound.

19. (canceled)

20. The spool according to claim 18, wherein at least a portion of the winding surface is at least one of parallel with the bobbin axis and tapered relative to the bobbin axis.

21. (canceled)

22. The spool according to claim 18, wherein one portion of the winding surface of the bobbin is tapered relative to the bobbin axis, and an adjacent portion of the winding surface is parallel relative to the bobbin axis.

23. The spool according to claim 22, wherein winding of the optical fibre on to the bobbin is initiated on the tapered portion.

24. The spool according to claim 22, wherein the first axial direction is a direction which is in an up-sloping direction of the tapered portion.

25. The spool according to claim 18, wherein the bobbin comprises a store region for storing a length of the optical fibre separately from the wrap segments, and the store region at least one of accommodates one end region of the optical fibre and is provided adjacent the winding surface of the bobbin.

26. (canceled)

27. (canceled)

28. (canceled)

29. (canceled)

30. (canceled)

31. The spool according to claim 18, wherein the bobbin comprises a discharge region to improve discharge of the fibre from the bobbin.

32. (canceled)

33. The spool according to claim 31, wherein the discharge region comprises an annular lip.

34. The spool according to claim 1, wherein at least a portion of the optical fibre comprises a coating.

35. (canceled)

36. (canceled)

37. The spool according to claim 1, wherein the spool is non-rotatable.

38. The spool according to claim 1, wherein at least a portion of the spool is rotatable.

39. The spool according to claim 38, wherein the spool is driven by a torque applied to the spool by the action of the fibre despooling therefrom.

40. The spool according to claim 1, comprising multiple spool portions, each comprising a plurality of overlapping wrap segments.

41. The spool according to claim 40, wherein the spool portions are rotatable relative to each other.

42. (canceled)

43. (canceled)

44. A method for winding a length of optical fibre to form a spool, the method comprising: winding the optical fibre around an axis of the spool to form a plurality of wrap segments arranged axially along the spool axis, wherein adjacent wrap segments partially overlap in the axial direction, each wrap segment being formed by winding a first wrap layer in a first axial direction over a first axial distance, and winding a second wrap layer over the first wrap layer in a reverse second axial direction over a second axial distance greater than the first axial distance, wherein at least one of the optical fibre extends continuously from the second wrap layer of one wrap segment to the first wrap layer of an adjacent wrap segment, and the method further comprises providing a change in winding pitch during transition from the first wrap layer to the second wrap layer.

45. A spool of optical fibre for mounting in a device such that the optical fibre can be despooled and deployed from the device, the spool comprising: a spool axis; a length of optical fibre wound around the spool axis to form a plurality of wrap segments arranged axially along the spool axis, wherein adjacent wrap segments partially overlap in the axial direction, wherein each wrap segment comprises a first wrap layer wound in a first axial direction and a second wrap layer wound over the first wrap layer in a reverse second axial direction, wherein a transition of the optical fibre from the first wrap layer to the second wrap layer is provided with a change in winding pitch.

46. (canceled)

47. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0101] These and other aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying Figures, in which:

[0102] FIG. 1 is a diagrammatic illustration of a device being deployed through a wellbore;

[0103] FIG. 2 is a perspective view of the device of FIG. 1;

[0104] FIG. 3 is a part sectional view of the device of FIG. 2, shown in perspective view;

[0105] FIG. 4 is a part sectional view of the device, shown in side elevation;

[0106] FIG. 5 is a perspective view of a bobbin of the device of FIG. 2;

[0107] FIG. 6 is a sectional view of an end region of the bobbin of FIG. 5;

[0108] FIGS. 7 to 18 provide sequential stages in winding an optical fibre on the bobbin of FIG. 5 to for a spool;

[0109] FIGS. 19 and 20 illustrate opposite ends of the formed spool during despooling of the fibre therefrom;

[0110] FIG. 21 is a part sectional view of a device with an alternative bobbin form;

[0111] FIG. 22 is a sectional view of an end region of the bobbin of FIG. 21;

[0112] FIG. 23 illustrates a spool of optical fibre, using the bobbin of FIG. 21, shown a discharge direction of the fibre during despooling from the spool;

[0113] FIG. 24 illustrates the spool of FIG. 23, with a fibre launch guide;

[0114] FIGS. 25 to 36 illustrate sequential stages in winding an optical fibre on an alternative bobbin to form a spool;

[0115] FIGS. 37 and 38 illustrate the spool formed in the sequence of FIGS. 25 to 36 showing discharge of the fibre in opposite directions during despooling of the fibre;

[0116] FIGS. 39 to 52 illustrate sequential stages in winding an optical fibre on an alternative bobbin to form a spool;

[0117] FIGS. 53 and 54 illustrate the spool formed in the sequence of FIGS. 39 to 52 showing discharge of the fibre in opposite directions during despooling of the fibre;

[0118] FIGS. 55 and 56 illustrate a sequence of forming an alternative spool of optical fibre;

[0119] FIGS. 57 and 58 illustrate the spool formed in the sequence of FIGS. 55 and 56 showing discharge of the fibre in opposite directions;

[0120] FIG. 59 illustrates an alternative form of a spool of optical fibre;

[0121] FIG. 60 illustrates the spool of FIG. 59, showing the fibre partially depleted from the spool;

[0122] FIG. 61 illustrates a device which includes a spool of optical fibre, with said fibre deployed from the device in a wellbore, wherein the fibre includes different properties in different axial sections; and

[0123] FIG. 62 illustrates a bobbin used to form the spool for including in the device of FIG. 61.

DETAILED DESCRIPTION OF THE DRAWINGS

[0124] Aspects of the present disclosure relate to a spool of optical fibre which may be mounted in a device such that the fibre may be deployed from the device. The device may traverse through a bore, such that the fibre becomes deployed within the bore. The device may be used in many applications or environments. For the purposes of the present description the device is for use within a wellbore, but it should be recognised that this is merely exemplary. It should be understood that the drawings presented are not provided to scale, and may not reflect actual dimensions, ratios, angles, number of features and the like.

[0125] FIG. 1 is a diagrammatic illustration of a device 10 deployed within a wellbore 12. The device 10 includes a spool 14 of optical fibre 16, such that as the device 10 traverses the wellbore 12 the fibre 16 is deployed from an exit 18 at the trailing end of the device 10. The fibre 16 may be used during or after deployment for multiple applications, such as for communication. In some examples the fibre 16 may be used for distributed sensing within the wellbore 12, such as distributed temperate sensing (DTS), distributed pressure sensing (DPS), distributed acoustic sensing (DAS), or the like.

[0126] A perspective view of the device 10 is provided in FIG. 2, illustrated in the direction of the exit 18 at the trailing end thereof. The device 10 is generally cylindrical in form, and in the present example includes centralising elements 20 at opposing ends thereof for facilitating centralisation of the device 10 in the wellbore 12 (FIG. 1).

[0127] FIGS. 3 and 4 provide alternative perspective views of the device 10, with a cavity region 22 shown in cross-section, wherein the cavity region 22 accommodates the spool of optical fibre. In this respect FIGS. 3 and 4 illustrate a bobbin 24 of the spool, with no fibre wound thereon for clarity purposes. The bobbin 24 is mounted within the cavity 22 in cantilever form such that the bobbin 24 defines a fixed or proximal end 26 and a free or distal end 28, and arranged to be coaxial with the axis 30 of the device 10.

[0128] The device 10 includes an internal funnel 32 which functions to guide fibre despooled from the bobbin 24 towards the exit 18. The exit 18 includes a throughbore 34 which is dimensioned to a similar diameter as the fibre, and in some examples the bore 34 may provide a degree of resistance to fibre passing therethrough. This may assist to control the rate of fibre deployment. In some examples a volume of grease or similar material may be provided within the cavity 22, for example within the internal funnel 32. Such grease may become coated on a fibre during deployment from the device 10. The grease may function to provide a degree of resistance to the deployment of the fibre, to permit the fibre to stick to a wall of the wellbore 12, to protect the fibre, to provide lubrication to the fibre and the like.

[0129] FIG. 5 provides a perspective view of the bobbin 24 removed from the device 10. The bobbin 24 includes a winding surface 36 which has a conical portion 38 and an adjacent cylindrical portion 40 for receiving fibre thereon, wherein the conical portion 38 is located towards the proximal end 26 of the bobbin 24 and the cylindrical portion 40 is located towards the distal end 28. The conical portion 38 defines a tapered surface relative to the axis 42 of the bobbin 24, whereas the cylindrical portion 40 defines a parallel surface relative to the bobbin axis 42.

[0130] The bobbin 24 further comprises an annular lip 44 at the distal end 28. As will be described in more detail below the annular lip 44 assists during despooling of fibre from the bobbin 24.

[0131] The bobbin 24 also includes an annular recess 46 at the proximal end 26, separated from the conical portion 38 by an annular lip 48. The annular recess 46 functions as a storage area to store one or more turns of optical fibre, such that an end of said optical fibre is readily accessible following winding onto the bobbin 24, facilitating any testing operations and the like prior to being installed in the device 10. FIG. 6 is a cross-sectional view of the bobbin 24 in the region of the proximal end 26, illustrating the form of the annular recess 46 and lip 48. A feed-through bore 50 is provided to allow fibre to pass from the recess 46 to the conical portion 38 of the winding surface 36.

[0132] In the present example the bobbin 24 includes an internal pocket 52 extending into the proximal end 26, wherein a further feed-through bore 54 is provided to facilitate passage of fibre from the annular recess 46 into the pocket 52. The pocket 52 may accommodate components or apparatus, such as one or more sensors, a light source, a light receiver, a controller, and the like. Fibre wound on the bobbin 24 may be connected to a component within the pocket 52.

[0133] A description of a sequence of winding a length of optical fibre will now be described with reference to FIGS. 7 to 18. Referring initially to FIG. 7, the bobbin 24 is illustrated in simplified form, showing the conical and cylindrical portions 38, 40 of the winding surface 36, and the bobbin axis 42. In FIG. 8 grease 56 is applied over the winding surface 36. Optical fibre wound onto the bobbin 24 will be pulled through the grease 56, such that the optical fibre becomes coated. Such an arrangement may facilitate easier coating of the fibre, rather than, for example, stripping the complete length of the fibre through a grease bath, although such an example alternative or supplemental way of applying grease may still be used. Any suitable grease may be used, or indeed any alternative coating material as required.

[0134] The initial winding stage of an optical fibre 58 is illustrated in FIG. 9, with the grease coating 56 not shown for clarity. Furthermore, with brief reference to FIG. 6, an end region of the fibre 58 may first be extended into the annular recess 46 (not shown in FIG. 9) before winding begins. Fibre extending from the recess 46 may extend along the conical portion 38 of the winding surface, to a winding start point 60 at the interface between the conical portion 38 and cylindrical portion 40 of the winding surface 36.

[0135] The fibre 58 is then wound in a first axial direction, indicated by arrow 62, relative to the bobbin axis 42 (which may also define a spool axis) to form a number of adjacent individual turns or wraps, at a steep winding pitch which provides the adjacent wraps in contact with each other (i.e., a closed winding pitch). In the present case the first axial direction is such that the fibre 58 is added to the bobbin 24 in an upslope direction of the conical portion 38, until reaching point 64, thus defining a first wrap layer 66. By winding in an upslope direction each wrap or turn provides support to the subsequent wound wrap or turn of the fibre 58.

[0136] As shown in FIG. 10, the fibre 58 is then wound in a reverse second axial direction, illustrated by arrow 68, over the first wrap layer 66 at a much shallower winding pitch, until reaching point 70 where the fibre 58 is on the cylindrical portion 40 of the winding surface 36, adjacent the starting point of the first wrap layer 66. This may form a first portion 72 of a second wrap layer 74. Following this, as shown in FIG. 11, winding of the fibre 58 is continued further in the second axial direction, illustrated by arrow 76, to form a second portion 78 of the second wrap layer 74, until reaching point 80. The second portion 78 of the second wrap layer 74 is wound at a steeper winding pitch (in this case a closed winding pitch) relative to the first portion 72 of the second wrap layer 74. The second portion 78 may function to provide support to the first wrap layer, and as such in some cases the second portion 78 may be defined as an anchor or anchor winding portion. The first and second wrap layers 66, 74 may form a first wrap segment 82.

[0137] Following this, as illustrated in FIG. 12, the fibre 58 is wound again in the first direction, illustrated by arrow 84, over the first wrap segment 82, at a closed wind pitch until reaching point 86 to form a subsequent first layer 88. Next, as illustrated in FIG. 13, the fibre 58 is wound in the direction of arrow 90, at a shallower winding pitch over the first layer 88 until reaching point 92, with the fibre 58 continuing to be wound in the direction of arrow 94 in FIG. 14 to complete a second wrap layer 96. The newly formed first and second wrap layers 88, 96 define a second wrap segment 98 which axially overlaps the first wrap segment 88, wherein each wrap segment extends to a common outer diameter.

[0138] The winding process may be continued in the same manner, as illustrated in FIGS. 15 to 18 to add further axially overlapping wrap segments (e.g., segment 100), each with first and second wrap layers, distributed along the length of the bobbin 24. The winding process may be continued until the required length of fibre 58 has been wound onto the bobbin 24 to form a complete spool. In some examples between 10 to 10,000 meters, and possibly more, of fibre 58 may be wound onto the bobbin 24, perhaps over 2 to 300, and possibly more, axially overlapping wrap segments.

[0139] The winding of the fibre 58 may be completed by winding a final wrap layer 97 in the direction of arrow 99 shown in FIG. 18.

[0140] The provision of partially overlapping wrap segments may be such that at least a proportion of one wrap segment is supported or constrained by the overlapping adjacent segment. Further, the multiple adjacent and overlapping segments may provide a degree of resistance to being disturbed by any object, such as the despooled portion of the fibre, dragging thereacross. Also, the supporting effect of the overlapping segments may be such that any requirement for end flanges may be minimised or eliminated.

[0141] FIG. 19 illustrates the fibre 58 being despooled from the bobbin 24, extending generally in the direction of the axis 42. During despooling the wrap layers of one segment are unwound before being unwound from an adjacent wrap segment, and so on. In this way, during despooling the wrap segments are each sequentially depleted, one after the other, in an axial direction, which may be referenced as the depleting direction, along the spool axis 42. In this respect, during despooling, the axial length of the spool will reduce in the depleting direction.

[0142] The axial fleeting movement or traverse made by a launch or release point 102 of the optical fibre 58 during despooling from an individual wrap layer is limited to the axial length of each individual wrap segment, and not, as conventionally known, the entire axial length of the spool, which may otherwise cause complications, such as from the unwound section of fibre effectively dragging across and possibly disturbing the windings still on the spool.

[0143] In the present example the bobbin 24 is rotatably fixed within the device 10. In such an arrangement the fibre launch point 102 will orbit the spool during despooling. In alternative examples the bobbin 24 may be rotatably mounted in the device 10. In such an arrangement the action of the fibre 58 despooling may apply a torque to the bobbin 24, thus causing said bobbin 24 to rotate.

[0144] With reference to FIG. 20, the annular lip 44 provided at the distal end 28 of the bobbin 24 functions to lift the fibre 58 from the winding surface of the bobbin 24. This may minimise the effect of a helix of the fibre 58 during discharge from radially binding against the bobbin 24, which may otherwise provide resistance to discharge, increasing the likelihood of fibre breakage. Furthermore, in some examples where a degree of adhesion may be present between the fibre 58 and the bobbin 24, for example caused by the presence of grease, the lifting effect provided by the annular lip 44 may assist to break this adhesion.

[0145] Reference is now made to FIG. 21 which illustrates the device 10 with an alternative form of bobbin 124. The bobbin 124 is similar in many respects to the bobbin 24 described above, and as such like features share like reference numerals, incremented by 100. Thus, the bobbin 124 extends from a proximal end 126 to a distal end 128 and includes a winding surface 136 having a conical portion 138 and a cylindrical portion 140. However, in the present example the conical portion 138 is located towards the distal end, and the cylindrical portion 140 is located towards the proximal end.

[0146] The proximal end 126 of the bobbin 124 includes an annular recess 146 for storing an end region of fibre when wound on the bobbin 124. As illustrated in FIG. 22, which is a cross-sectional view through the proximal end region of the bobbin 124, a feed-through bore 150 extends between the recess 146 and the winding surface 136 of the bobbin 124, and similarly a feed-through bore 154 extends between the recess 146 and a pocket 152 in the end of the bobbin 124.

[0147] Fibre may be wound on the bobbin 124 in the same manner described above, with winding initiated again at the interface between the conical and cylindrical portions 138, 140. FIG. 23 illustrates the bobbin 124 loaded with fibre 58, with the fibre 58 being despooled in the direction of the spool axis 142. In this case the fibre 58 passes across the wrap segments. However, the nature of the overlap of the wrap segments provides a robust arrangement which may resist being disturbed by the despooled portion of the fibre.

[0148] In FIGS. 21 to 23 the bobbin 124 is rotatably fixed within the device 10, such that a launch point 202 of the fibre 58 orbits the spool. However, in other examples the bobbin 124 may be rotatably mounted within the device 10. FIG. 24 illustrates the bobbin 124 in a rotatable format, such that the fibre launch point 202 is provided at a fixed rotatable location. In the example illustrated a launch guide 103 is provided which includes a lead screw 104 gear coupled to the bobbin 124 via a drive train 105. A carriage 106 is mounted on the lead screw which is engaged with the fibre 58. During rotation of the bobbin 124, the carriage 106 axially traverses along the lead screw 104, lifting the fibre 58 from the outer spool surface. In some examples the rotation of the bobbin 124 may be measured, with the measurement used to determine the length of fibre 58 which has despooled.

[0149] In the example shown in FIG. 24, the device 10 is configured such that the carriage 106 remains in advance of the fibre launch point 202, as the fibre 58 is despooled. In other similar words, the carriage 106 may be considered to be displaced in an axial direction, relative to the launch point 202, and in the direction that the fibre is being despooled (as is shown in FIG. 24). This may assist with ease of despooling. Of course, in other examples, the carriage 106 may be retarded relative to the launch point 202, or indeed be positioned around the launch point 202 (e.g. approximately aligned axially with the launch point 202). It will be appreciated also that, depending on the progression of despooling, the carriage 106 may at times be in advance of the launch point 202, while at other times be retarded relative to the launch point 202.

[0150] In the examples provided above the bobbin includes a winding surface having both conical and cylindrical portions. However, other forms of bobbin may be provided, an example of which is shown in FIG. 25. The bobbin 224 is in some ways similar to the bobbin 24 first shown in FIG. 3, and as such like features share like reference numerals, incremented by 200. The bobbin 224 includes a winding surface 236 which includes only a conical portion 238 with a tapering surface relative to the bobbin axis 242.

[0151] A sequence of winding fibre 58 on the bobbin 224 is shown in FIGS. 26 to 36. Referring initially to FIG. 26, winding is initiated at point 260, with the fibre 58 being wound in an upslope direction, illustrated by arrow 262, in a closed winding pitch until reaching point 264, thus defining a first wrap layer 266.

[0152] As shown in FIG. 27, the fibre 58 is then wound in a reverse second axial direction, illustrated by arrow 268, over the first wrap layer 266 at a much shallower winding pitch, until reaching point 270, when the fibre 58 continues being wound at a closed winding pitch, as illustrated in FIG. 28, in the direction of arrow 276 to point 280 thus forming a second wrap layer 274 and completing a first wrap segment 282. This sequence is repeated, as illustrated in FIGS. 29 to 36, until the desired length of fibre 58 is wound. In this respect individual wrap segments may eventually begin to extend to a common outer diameter, as shown in FIGS. 34 to 36.

[0153] The fibre 58 may be despooled in either axial direction from the bobbin 224, as shown in FIGS. 37 and 38.

[0154] An alternative bobbin 324 is illustrated in FIG. 39 and includes a winding surface 336 which includes only a cylindrical portion 340 with its surface parallel to the bobbin axis 342. A sequence of winding fibre 58 on the bobbin 324 is shown in FIGS. 40 to 52. Referring initially to FIG. 40, winding is initiated at point 360 and extends in the direction of arrow 362, in a closed winding pitch until reaching point 364, thus defining a first wrap layer 366.

[0155] As shown in FIG. 41, the fibre 58 is then wound in a reverse second axial direction, illustrated by arrow 368, over the first wrap layer 366 at a much shallower winding pitch, until reaching point 370, when the fibre 58 continues being wound at a closed winding pitch, as illustrated in FIG. 42, in the direction of arrow 376 to point 380 thus forming a second wrap layer 374 and completing a first wrap segment 382. This sequence is repeated, as illustrated in FIGS. 43 to 52, until the desired length of fibre 58 is wound. It should be noted that FIG. 43 shows the first layer 388 of a second wrap segment being laid down, and FIG. 44 illustrates this first layer 388 in cross section. The individual wrap segments may eventually begin to extend to a common outer diameter, as shown in FIGS. 50 to 52.

[0156] The fibre 58 may be despooled in either axial direction from the bobbin 324, as shown in FIGS. 53 and 54.

[0157] Reference is now made to FIG. 55 which shows a bobbin 424, similar to bobbin 24 first shown in FIG. 3, with fibre 58 wound thereon. A cylindrical housing 423 is provided over the fibre 58. As illustrated in FIG. 56 the bobbin 424 is removed, for example by being extracted, melted, disintegrated or the like, leaving the fibre 58 in place. As illustrated in FIGS. 57 and 58, the fibre 58 may be despooled from an inner diameter of the spool in either direction of the spool axis 442.

[0158] Reference is now made to FIGS. 59 and 60, which shows a further example spool of optical fibre, generally identified by reference 524. The spool 524 includes multiple bobbins 524a-c connected together in end-to-end relation along a common spool axis 542. A continuous length of fibre 58 is wound around each bobbin 524a-c, for example in the same manner described above, such that each bobbin 524a-c includes a plurality of axially overlapping wrap segments 582. In the present example the entire spool 524 may be rotatably mounted within a device, and the individual bobbins 524a-c are rotatably mounted relative to each other.

[0159] When the spool 524 is fully loaded, despooling may cause the entire spool 524 to rotate in unison, or indeed the spool 524 may remain static depending on the torque applied during despooling. As the fibre 58 is depleted, for example fully depleted from the first bobbin 524a, the fibre 58 may form a helix around said first bobbin 524a. The ability of the first bobbin 524a to rotate may be such that the helix of fibre may apply a torque sufficient to allow the first bobbin 524 to rotate. However, it will be appreciated that in circumstances in which some or all of the bobbins 524a-c are configured to rotate, it may be the case that after a bobbin has been depleted (e.g. 524a), then that depleted bobbin may rotate less so than the rotation experienced by a despooling bobbin. At some point, during despooling of the fibre 58 from the device 10, a particular depleted bobbin may indeed stop rotating (e.g. as fibre 58 passing thereacross the depleted bobbin may not cause sufficient torque to cause the bobbin to rotate). In some cases, a depleted bobbin may stop rotating, or reduce the rate of rotation, even though the following depleting bobbin continues to rotate (and potentially rotates in synchrony with some or all of the yet to be despooled bobbins).

[0160] Reference is now made to FIG. 61 which diagrammatically illustrates a device 610 traversing a wellbore 612 while deploying a fibre 616 therefrom such that the fibre 616 is installed in the wellbore 612. In some examples the fibre 616 may define separate axial portions 616a, 616b which comprise or exhibit different properties. In some examples a different fibre type may be provided in each portion 616a, 616b. Alternatively, a different coating may be applied on the different fibre portions 616a, 616b. The different properties applied along the fibre 616 may be provided to accommodate the particular environment in which the fibre 616 is deployed. For example, additional protection to the fibre 616 may be preferred in an upper region (portion 616b) of the fibre, etc.

[0161] The nature of a fibre winding arrangement as described herein may facilitate an efficient manner of applying a different coating between the different axial portions of the fibre 616. For example, FIG. 62 diagrammatically illustrates a portion of a bobbin 624 which is similar to bobbin 24 first shown in FIG. 3. In this example, before any fibre is wound thereon, a material, such as grease 656 is applied on the outer surface of the bobbin 624, in the same manner shown in FIG. 8. However, in this case a first type of grease 656a is provided over a first axial length of the bobbin 624, and a second type of grease 656b is provided over a second axial length of the bobbin. The different types of grease may be differentiated by viscosity, NGLI number or the like. In this way, as fibre is wound onto the bobbin, different axial portions will become coated with the different types of grease 656a, 656b.

[0162] It should be understood that the examples provided are merely exemplary of the present disclosure, and that various modifications may be made thereto.