NO344472B1

NO344472B1 - A winding apparatus

Info

Publication number: NO344472B1
Application number: NO20180972A
Authority: NO
Inventors: Erik Zachariasen; Mads Bjørnenak; Bergtor Haugå
Original assignee: Stimline As
Priority date: 2018-07-10
Filing date: 2018-07-10
Publication date: 2020-01-13
Also published as: CA3109332A1; CA3109332C; WO2020013702A1

Description

Technical Field

The present invention relates to a winding apparatus for elongate members, especially a cable or coiled tubing used for well intervention in the oil and gas industry, as defined by the preamble of subsequent claim 1. The invention also concerns a method to continuously determine a position of an elongate member on a reel according to subsequent claim 10.

A particular problem with the cables and coiled tubings used for intervention of oil or gas wells is that the cable or tube, which initially has a circular crosssection, when used will be squeezed due to the great forces needed to feed the cable or tubing into the well or retract it from the well. This results in uneven cross-sections, bumps and bends in the cable or tubing. These distortions of the cable or tubing makes it particularly difficult to spool. There will easily form gaps between windings and the cable or tubing may easily climb the previous winding. If this happens, the next layer of windings will also be uneven and the faults in the winding will increase for each layer. This in turn results in additional distortions of the cable or tubing, which greatly reduces the life span of the cable or tubing.

Hence, a proper spooling of the elongate member is of vital importance to ensure a sufficiently long-life span and thereby save costs.

Background Art

GB2221227 describes a winding apparatus for winding of a cable on a reel. The purpose is to wind the cable so that it forms a perfect helix. To achieve this the apparatus is equipped with a laser emitter and cameras. The fixedly arranged laser emitter throws a line of light over the reel, between the two flanges of the reel. The two cameras see the line and the image is analysed by a process and control system. This system is configured to detect deviations in the windings of the cable, in particular if there is a too large gap to the previous winding or if the cable is climbing the previous winding. If a deviation is detected the motor that causes the sideways movement of the winding apparatus will be adjusted. The system is also capable of detecting the end flanges. The apparatus may also have other sensors, such as position sensors or rotation sensors.

EP0602504B1 concerns winding of electrical cables and the like. The invention of this publication aims to improve the solution of GB 2221227, because the latter will only discover an erroneous spooling after it has happened and can thereby only correct for further erroneous spooling. In one embodiment the reel is sideways moveable, and in alternative embodiments a spooling carriage is sideways moveable.

In the version with a sideways moveable reel, the laser emitter is fixedly mounted to the support structure. The laser emitter creates a wide but thin beam, with the with extending between the flanges of the reel which the reel is travelling from side to side. The wide beam crosses the cable somewhere between the spooling apparatus and the pint where the cable meets the reel (or rather the windings that have already been laid on the reel. A camera images the laser reflected from the line. Based on an analysis of the image the speed of the motor that moves the reel is adjusted. The rotational speed of the reel is also determined.

An essential feature of this known device is to detect a point on the cable that is being fed onto the reel. The desired position of this point and the desired velocity relative to the horizontal axis are compared with the measured position and velocity. The distance between the flanges is also detected. When the cable laying direction turns at the flange, the angle of the cable is altered so that it is laid on top of the winding below.

As the reel is moving sideways while the laser emitter is stationary, the laser emitter is in effect moving sideways relative to the reel. The spooling carriage and the laser emitter are, however, stationary relative to one-another.

US7370823B2 shows an apparatus for winding up a wire, fibres or similar.

Several different sensors are described to measure the distance to the wire, inter alia a laser emitter. With the laser emitter the position of the flanges, the entering angle of the wire and the apices and valleys of the winding are determined. The measurements form the basis for determining the winding speed and the travelling speed of the winding carriage.

The publication claims that the method is versatile enough to be used on different reel geometries, such as cylindrical and conical spools.

The sensor unit, which may comprise a laser, is mounted on the winding carriage for the wire, and it will therefore move from side to side along with the carriage. The winding of the wire and the laser beam are therefore fully synchronized at all times.

A microprocessor collects data from the sensor unit and measures inter alia the feeding velocity of the of the wire to be spooled. On the basis of this the rotational speed of the reel and the travelling speed of the spooling carriage are adjusted

As the laser unit is mounted on the spooling carriage, it cannot move independently of the spooling carriage.

WO2008012093A2 describes a spooling apparatus for yarn. The apparatus utilizes a laser emitter. The laser beam from the emitter is split into two laser beams, which are again merged at the thread of the yarn. By reflected laser and the doppler effect the yarn quality and if there is a break in the thread will be determined. The system can also determine if the spool is full.

The system can make a velocity profile for the thread and determine from this both variance and standard deviation. A deviation from the desired values of these parameters will lead to a regulation of the spooling.

The laser beam seems to be fixed and the movement of the thread relative to the laser beam is used to determine the velocity of the thread. There seems to be no determination of the positioning of the windings or their position relative to the end flanges.

WO 2014/068084 describes a System for controlling the loading or unloading a cable or the like onto a drum, wherein the drum has a known first rotation axis loading or unloading the cable, the system also comprises an imaging means aimed at the cable from a position at a distance from the drum rotation axis, the imaging means being adapted to measure the direction of the cable relative to the rotational axis of the drum. The imaging means can be constituted by a 3D video camera. There is no use of laser in this system.

Summary of invention

The present invention aims to improve the accuracy of the spooling of an elongate member, especially a cable or coiled tubing used for well intervention in the oil and gas industry.

This is achieved by a winding apparatus for elongate members, comprising a storage reel capable of receiving the elongate member on a core thereof; further comprising a spooling device, said spooling device having a spooling head, which is adapted to travel back and forth along the reel to load the elongate member onto the reel; a laser measurement assembly arranged to travel back and forth along the reel to determine a position of the elongate member along the length of the core, characterised in that the laser measurement assembly is arranged at an angular distance in the rotational direction of the reel from a point where the elongate member is laid to rest on the reel, and said laser measurement assembly traveling along the core independently of said spooling head; the laser measurement assembly being set to emit two parallel laser beams with a mutual distance, said mutual distance being less than a diameter of said elongate member; and said laser measurement assembly having at least one receiver receiving a reflection of said laser beams from a surface of said elongate member, said laser measurement assembly determining a travel distance of said laser beams to the surface of said elongate member based on said reflection.

The distance between the laser beams is adapted to the diameter of the elongate member, so that the laser beams hit the elongate member at the inclined surface of each side of the center line of the elongate member.

The laser measurement assembly is placed about the reel so that the two laser beams can be aimed at the elongate member about 60° after the point where the elongate member is spooled, i.e. laid, on the reel.

A processor compares the difference in distances from the laser emitters to the elongate member. If the distances are not equal, the carriage that carries the laser emitters is adjusted sideways until the distances are equal. This adjustment of the position of the carriage is done continuously in a closed loop system. The adjusted position of the carriage is sent to the control system for the spooling carriage, which uses this position to adjust the position of the spooling carriage.

By the apparatus according to the invention, a greater accuracy of the spooling is achieved.

The invention also relates to a method of continuously determine a position of an elongate member on a reel during spooling of said elongate member onto or off said reel, characterised in that travelling distances to a surface of said elongate member of two parallel laser beams, with a mutual distance less than a diameter of said elongate member, are compared; if the travelling distances are not equal, a carriage, from which the laser beams are emitted, is moved in the longitudinal direction of the reel until the travelling distances are equal, a position of said carriage along the length of said reel when the travelling distances are equal, defining the position of said elongate member on the reel.

The processor may use various algorithms to control the spooling of the elongate member. Below are examples of such algorithms:

Algorithm 1

The algorithm continuously compares the distance from the two laser sensors to the elongate member. Based on the deviation in distance the algorithm will move the laser carriage with sensor directly over the elongate member.

In this way the elongate member position will be tracked as it is spooled on to the drum and the algorithm calculate the optimal position of the guide head. These calculations will ensure the best possible spooling conditions and minimize the risk of the elongate member becoming damaged during spooling on or off the drum.

Algorithm 2

The algorithm will track and store the x and y position of the elongate member continuously. Based on the position of past wraps on the drum, the algorithm will output two analog deviation signal X (error) and Y (error). These two signals will tell how much the spooling is «off» compared to optimal spooling position.

The error signals are used for alarm generation and automatic corrections.

Algorithm 3

A spooling quality record algorithm compares all the spooling deviation values for the complete drum and output a spooling quality record. This record may show percentage elongate member length in each error category.

Algorithm 4

An elongate member oval factor algorithm calculates a 3D-model of the actual layer as it is spooled on to the drum. Based on the surface position scanned in the last layer, the algorithm calculates an elongate member oval factor as a continuous output signal. This oval factor is then used for automatic control of spooling tension to optimize the elongate member life and or the spooling quality.

Algorithm 5

A drum calibration/layer scan algorithm moves the laser along its rail relative to drum rotation as the drum is rotated in steps to generate a 3D scan of the drum to detect layer measurements, shape of layer, wrap gaps on last layer, etc. The algorithm will also find the base parameters to start spooling on the elongate member. Based on the scan the system will automatic detect drum type for multi drum systems.

When the spooling is to be commenced, the laser measurement assembly is used to detect the position and the shape of the reel flanges and thereby determine if the flanges have become bent.

Brief description of drawings

The present invention will now be explained in more details, referring to the enclosed drawings, in which:

Figure 1 shows in an isometric view a reel for winding up an elongate member, and which is equipped with the laser sensor of the present invention,

Figure 2 shows a side elevation view of the reel of figure 1,

Figure 3 shows in planar view the reel of figure 1,

Figure 4 shows a part of the figure 3 in enlarged view,

Figure 5 shows a further enlarged part of figure 4 with the laser beams hitting the elongate member equally at each side,

Figure 6 shows a view similar to figure 5 but with the laser beams hitting at different distances from the centre of the elongate member,

Figure 7 illustrates a first algorithm of the invention, and

Figure 8 illustrates a second algorithm of the invention.

Detailed description of the invention

Figure 1 shows a reel assembly with a reel 1. The reel comprises a core to receive an elongate object 2 and a flange at respective ends of the core. In the shown embodiment the reel assembly is for winding up a coiled tubing 2, but it can be used for any other type of elongate member with a relatively uniform and circular cross-section. The reel assembly comprises a spooling device 7, which generally consists of a guide rail 8 along which a carriage 9 is capable of travelling. The carriage is in turn carrying a spooling head 10 at an outer end of a pole 11. A non-winded part 12 of the coiled tubing extends through the spooling head 10.

The carriage 9 is coupled to a rotating screw 13, which extends along the guide rail 8. By turning the screw 13, the carriage 9 will travel along the rail 9, from one end of the rail 8 to the other in a reciprocating motion.

The rail is fixed to a set of arms 14, which in turn are mounted to a frame 15, which also carries the reel 1. The mounting of the arms 14 to the frame 15 is preferably by a hinge 16. A hydraulic cylinder 17 extends between a respective arm and the frame 15, enabling movement of the arms 14 about the hinge 16.

The screw 13 is equipped with a rotary sensor 18, which logs the rotational position of the screw at any given time.

The reel 1 is rotatably suspended in the frame 15 via a bearing 19. A motor 20 is coupled to the reel 1 to rotate the same. The motor is equipped with a rotary sensor 21 that is capable of logging the rotational position of the motor, and hence the reel, at any given time.

At the opposite side of the spooling device, is arranged a laser measurements assembly 22. The assembly 22 comprises a rail 23 that is attached to the frame 15 and a laser carriage 24 that is moveable long the rail 23, driven by a motor and a spindle, belt or similar (not shown). The laser carriage 24 has two laser emitters 24a and 24b (see figure 4). The laser emitters 24a and 24 b emits two parallel laser beams 25a and 25b.

The laser assembly will be explained in further detail below.

Figure 2 shows the reel assembly of figure 1 in a side elevation view. It shows the reel 1 with the coiled tubing 2. The frame 15, which supports the reel 1 and the arms 14 for supporting the rail 8 and the carriage 9. The laser emitters (only one visible) 24a, b are indicated at an angular distance about 60° after, in the direction of rotation of the reel, the point where the coiled tubing 2 is laid on the reel 1.

Figure 3 shows the reel assembly in planar view. As is clearly seen in this figure, the coiled tubing 2 has been laid evenly and uniformly on the reel 1 with the upper winding exactly on top of the lower winding.

Figure 4 shows an enlarged detail of figure 3. It shows the laser emitters 24a and 24b. and the laser beams 25a and 25b. As can be seen from this figure, the beams meet the coiled tubing 2 at each flank thereof.

Figure 5 shows an even more enlarged view of the laser beam and coiled tubing interface. It shows a winding 2a, which is the latest laid winding on the reel 1, and the two laser beams 25a and 25b, which are parallel and at a fixed mutual distance. In this situation the beams 25a and 25b hit the winding 2b at points A and B, respectively, which are at opposite but equal distances from the centre line 26 of the winding 2b. The distance from the centre line 26 can for instance be where the surface of the winding is at 45° to the centre line 26, however other distances are also conceivable. Lines 27a and 27b are the chords of the surface at the points A and B, respectively, of impact of the laser.

As the outer surface, the coiled tubing is not a perfect mirror, some of the laser light will reflect back to a light sensing unit (not shown) close to the laser emitters. There may be a common sensing unit for both emitters 24a and 24b, but there may also be a separate sensing unit for each emitter.

The laser beams are preferably pulsed, so that the time from the emittance of the laser pulse until the reflection is received at the sensing unit can be measured and will give the distance from the laser unit 24 to the surface of the winding with a high degree of accuracy. In order to avoid that the reflections from the two laser beams disturb one-another, the beams may be pulsed at alternating points of time, have different frequencies of light or be differently coded pulses.

If the distances from the laser unit 24 to the two points on the surface of the winding are the same, this means that the centre line 26 of the winding lies in the middle between the laser beams 25a, 25b. Hence the position of the laser unit 24 will correspond to the position of the winding.

Figure 6 shows a similar view as figure 5, but with the exception that the two laser beams 25a and 25b do not hit the winding 2a at an equal distance from the centre line 26, but at points A’ and B’, where A’ is closer to the centre line 26 than point A and point B’ is further away from the centre line than point B. This results in a difference in distance between the laser unit 24 and the two points A’ and B’, point A’ being closer to the laser unit 24 than point B’. This means that the centre line 26 lies to the left (upwards in figure 6) of the middle between the laser beams 25a and 25b. According to the invention the laser unit will be moved to the left (upwards in figure 6) until the distance between the laser unit 24 and the two points of impact are again the same. When this is the case, the position of the laser unit will correspond to the winding 2b.

The laser unit 24 is equipped with a position sensor (not shown). This position sensor can be a rotary sensor that senses the rotary position of a screw (not shown) that moves the laser unit 24 along the rail 23. Hence, the position of the laser unit 24 is tracked at all times.

The position of the winding carriage 9, and hence the winding head 10, is tracked in a similar way. Hence the position of the winding head is also tracked at all times.

The rotary position of the reel 1 is, as described above, also tracked at all times.

From these position data, it is possible to log an accurate position profile for the windings of the coiled tubing 2, including any gaps between windings. From this profile any bends, bumps and ovalities of the coiled tubing may be taken into account when the tubing us unwound for injection into a well. The injector for the tubing may be adjusted to accommodate for sections of tubing with such unevenness, and it may also attempt to straighten out bends.

During winding-up of the coiled tubing, the winding head may be adjusted to reposition a winding that is not laid at the desired position. The reel may be turned somewhat in reverse to lift the coiled tubing up again from the reel, and the carriage 9 with the winding head 10 be moved along the rail 8 a distance corresponding with the difference in desired position and measured position before the reel 1 is again turned to receive tubing.

Before the winding-up of coil commences, the laser unit 24 may be driven along the length of the rail 23 to detect the position of the flanges of the reel 1. When one of the beams 24a or 24b hits the flange, the measured distance will be substantially shorter. Then the reel may be turned, so that the laser can detect if the flange is bent. If the distance from the laser unit 24 to the surface of the flange changes substantially, this is an indication that the flange is bent. During the turning of the reel, the laser unit 24 may be moved slightly back and forth on the rail 23 to detect the amount of bending of the flange.

The accurate position of the flange, i.e. the inner surface of the flange, is logged so that the system knows exactly where the flange can be expected to be during the winding-up of the coil.

When the stored position of the flange is reached during winding-up, the system prepares to turn the direction of travel of the winding head 10, to wind the next winding of coil on top of the last winding before reaching the flange. In this way, the turning of the winding direction can be made at the exact right point. Hence, there will be no substantial gaps between the windings and the flanges or any unwanted climbing of the windings next to the flanges.

Figures 7 and 8 show flow charts illustrating the basic functions of two algorithms of the system of the invention. These and other algorithms will be run by a processor implemented into the system.

Figure 7 illustrates schematically algorithm 1, mentioned initially. Before initiating the method of algorithm 1, the inner end of the elongate member is attached to the reel and the spooling carriage 9 and laser carriage 24 are aligned with the inner end of the elongate member. According to algorithm 1 the first step is to start rotation of the reel at 30. As the reel rotates, preferably at a fixed rotational speed, the laser emitters 24a and 24b sends out laser beams 25a and 25b. The reflections of the beams are detected by sensors and the sensors provide the resulting distance measurements as input signals 1 and 2, shown by 31 and 32, to the algorithm at 33. The algorithm then performs a comparison of the two signals at 34. If the signals are equal, the algorithm merely instructs a further reading of the signals.

If the signals are not equal, the algorithm checks at 35 if the distance signal 1 is smaller than the distance signal 2. If this is true, the algorithm instructs, denoted by 36, the motor driving the laser carriage 24 to move an increment sideways to the left, as seen from the carriage towards the reel.

If the signal 1 is not smaller than the signal 2, the algorithm checks if the opposite is true, i.e. if the signal 1 is greater than the signal 2, se reference numeral 38. If this is true, the motor is instructed, denoted by 37, to move the carriage 24 an increment to the right.

When either the instruction 36 or 37 has been performed, the signals from the sensors are read again and another comparison are made. This process is repeated continuously in an effort to move the carriage 24 until the two distance signals are equal. Each time the signals are equal, the position of the carriage is logged. At the same time the length of elongate member from the inner end to the point where the laser beams hit the elongate member is logged. The measuring of elongate member length may be done by conventional means, such as a measuring wheel mounted on the spooling carriage.

The above logged measurements are stored for later use, as they provide information on the quality of spooling of the elongate member.

Each time the elongate member reaches one of the end flanges, the direction of movement of the laser carriage 24 will be reversed, so that compared with the above, if the distance signal 2 is smaller than the distance signal 1, the carriage 24 will be moved to the right, and vice versa.

Figure 8 illustrates the function of the algorithm 2 mentioned initially. After the initial set-up, which is explained in connection with figure 7, the rotation of the reel is started, as denoted by 40. The laser carriage position 41, as determined by the algorithm 1 explained in connection with figure 7, the spooling carriage position 42, which may be determined by the algorithm 1 explained in connection with figure 7, and an offset value 43, are read into the algorithm, as denoted by 44.

The basis for the spooling carriage position is a mathematical function that takes into account the diameter of the elongate member, the reel diameter and the reel width. The function also takes the laser carriage position into account.

The spooling carriage position is determined by a theoretical model and the actual position of the elongate member on the reel. The laser sensor is one of several sensors that gives input to the control system, determining the spooling carriage position. Other sensors are, e.g., rotary sensor 21 on the reel rotation motor, rotary sensor 18 on the screw moving the spooling carriage and position sensor of the laser carriage.

The spooling carriage position is determined by a function that inputs the diameter of the elongate member, the reel diameter, the reel width and the laser carriage, thereby creating a closed loop system.

The offset value is determined first and foremost by the diameter of the elongate member. If the elongate member has a perfect circular cross section with a constant diameter, the offset could be a constant. However, in the primary field of the present invention, which is a cable or tubing for well intervention, the cable or tubing will be squeezed during use, resulting in deformations and ovalities. These unevennesses of the elongate member is, according to an aspect of the present invention, taken into account. When the elongate member is spooled onto the reel after use, or when it is spooled off the reel to be used, the position of the elongate member on the reel is continuously measured, such as by algorithm 1 explained in connection with figure 7. If the position of a part of the elongate member deviates from the ideal position, this is an indication of an unevenness of the elongate member in this part. The location of this unevenness along the elongate member is stored and used as an input parameter to determine the offset of the cable when this part of the cable is to be spooled onto the reel.

When the laser carriage 24 position 41 and the spooling carriage 9 position 43 have been entered into the algorithm, the targeted spooling carriage position is adjusted by the offset value to a set spooling carriage position, as denoted by 45. When the spooling carriage 9 is moving in a first direction along the reel 1, the offset value is determined to be positive, and when the spooling carriage 9 is moving in the opposite direction, the offset value is determined to be negative.

Next the algorithm checks, as denoted by 46, if the set spooling carriage position, i.e. including offset, is equal to the actual spooling carriage position.

If the set and actual spooling carriage positions are equal, the algorithm goes back continuing receiving the input values for laser carriage position 41, offset 42 and spooling carriage position 43.

If the values are not equal, the algorithm checks if the set spooling carriage position is smaller than the actual spooling carriage position, as denoted by 47. If this is true, a signal is sent to the motor driving the spooling carriage 9 to move the spooling carriage an increment to the left along the reel 1 axis, as denoted by 49.

If the above is not true, the algorithm checks if the set spooling carriage position is greater than the actual spooling carriage position, as denoted by 48. If this is true, a signal is sent to the motor driving the spooling carriage 9 to move the spooling carriage an increment to the right along the reel 1 axis, as denoted by 50.

After the incremental adjustment of the spooling carriage 9, the algorithm continues to receive inputs for the laser carriage position 41, offset 42 and spooling carriage position 43 and compare values as shown by 46, 37 and 48 in figure 8.

To determine exactly when the spooling carriage should change its travelling direction when the flange has been reached, the average travelling distance for the laser beams is used to chart the climb of the elongate member from one layer to the next, i.e. which angle the reel has turned between the lower layer to the immediate upper layer. This angle is called the climb angle. After the elongate member has reached the immediate upper layer, the reel is turned almost one revolution, with the spooling carriage in the same position, before the spooling carriage is moved away from the flange. The climbing angle is a factor that determines how large a fraction of one revolution the reel is turned before the spooling carriage is moved. Other factors that determine the rotation of the reel with a stationary spooling carriage are the diameter of the elongate member, the stiffness of the elongate member and the diameter of the reel at the layer.

Claims

1. A winding apparatus for elongate members (2), comprising a storage reel (1) capable of receiving the elongate member (2) on a core thereof; further comprising a spooling device (7), said spooling device (7) having a spooling head (10), which is adapted to travel back and forth along the reel to load the elongate member onto the reel; a laser measurement assembly (22) arranged to travel back and forth along the reel (1) to determine a position of the elongate member (2) along the length of the core, characterised in that the laser measurement assembly (22) is arranged at an angular distance in the rotational direction of the reel from a point where the elongate member (2) is laid to rest on the reel (1), and said laser measurement assembly (22) traveling along the core independently of said spooling head (10); the laser measurement assembly (22) being set to emit two parallel laser beams (25a, 25b) with a mutual distance, said mutual distance being less than a diameter of said elongate member (2); and said laser measurement assembly having at least one receiver receiving a reflection of said laser beams from a surface of said elongate member, said laser measurement assembly (22) determining a travel distance of said laser beams (25a, 25b) to the surface of said elongate member (2) based on said reflection.

2. The winding apparatus of claim 1, characterised in that it comprises a processor that is adapted to determine the position of the elongate member (2) on the reel (1) by making the laser measurement assembly (22) moving along the reel (1) until the travel distances of the two laser beams (25a, 25b) to the elongate member (2) are equal.

3. The winding apparatus of claim 1, characterised in that it comprises a processor that is adapted to determine the position of the elongate member (2) on the reel by using the difference in travel distances of the two laser beams (25a, 25b) and a radius of the cross-section of the elongate member (2).

4. The winding apparatus of any of the preceding claims, characterised in that the processor, when detecting a deviation of the measured position from an optimal position, is adapted to signal the spooling head (10) to move a distance along the reel (1) that brings the elongate member (2) to the optimal position.

5. The winding apparatus of claim 4, characterised in that the processor is capable of signalling a motor (20) that rotates the reel (1) to wind back elongate member (2) so that it can be placed at the optimal position.

6. The winding apparatus of any of the preceding claims 2-5, characterised in that the position of the elongate member (2) is logged in a data storage.

7. The winding apparatus of any of the preceding claims, characterised in that the laser measurement assembly (22) is adapted to be driven along the length of the reel (1) to detect the position of the flanges.

8. The winding apparatus of any of the preceding claims 2 - 7, characterised in that the processor is capable of determining gaps between adjacent elongate members (2) and output position of said gaps to a screen or data storage.

9. The winding apparatus of any of the preceding claims, characterised in that an offset of the spooling head (10) position is adjustable based on the diameter of the elongate member (2) and detected deformations of the elongate member (2).

10. A method to continuously determine a position of an elongate member on a reel during spooling of said elongate member onto or off said reel, characterised in that travelling distances to a surface of said elongate member of two parallel laser beams (25a, 25b), with a mutual distance less than a diameter of said elongate member, are compared; if the travelling distances are not equal, a carriage (24), from which the laser beams are emitted, is moved in the longitudinal direction of the reel (1) until the travelling distances are equal, a position of said carriage (24) along the length of said reel (1) when the travelling distances are equal, defining the position of said elongate member on the reel.

11. The method of claim 10, characterised in that a rotational angle of the reel (1) for the elongate member (2) to climb from one layer to the next layer is determined by a change in an average travelling distance of the two laser beams (25a, 25b).