WO2019215070A1

WO2019215070A1 - Downhole inspection assembly

Info

Publication number: WO2019215070A1
Application number: PCT/EP2019/061519
Authority: WO
Inventors: Øyvind HOVLAND; Ørjan HAGEN; Tore HOVLAND; Johan KLEIBERG JENSEN
Original assignee: Vision Io As
Priority date: 2018-05-07
Filing date: 2019-05-06
Publication date: 2019-11-14
Also published as: NO20180655A1

Abstract

The present disclosure relates to an inspection assembly (1) for inspecting the interior of a fluid filled pipe (100), such as oil and gas wells, production and workover risers and the like. The inspection assembly (1) comprises a sensor chamber (10) arranged in a sensor chamber housing (11) and a control chamber (20) arranged in a control chamber housing (11), the sensor chamber (10) and the control chamber (20) being directly or indirectly connected to each other. The sensor chamber (10) comprises three or more sensor assemblies (12) and the three or more sensor assemblies (12) are arranged around the circumference of the sensor chamber housing (11) in an essential helical sequence to receive sensor signals from the interior of the pipe (100).

Description

Downhole inspection assembly Technical Field

The present disclosure relates to an inspection assembly adapted to inspect the interior of a pipe. Moreover, the present disclosure relates to a method for inspecting and capturing images of the interior of a pipe.

Background

In the drilling and production of oil and gas wells, it is often desired to obtain information concerning conditions within a borehole. For example, tools and other objects may become lodged in the borehole during the drilling of a well. Such objects must be retrieved before drilling can continue.

In the operation and/or periodic maintenance of exploration, production or injection wells, it is frequently desired to obtain information about the construction and/or operating conditions of equipment located downhole. For example, detection of the onset of corrosion damage to well tubing or casing within a borehole enables the application of anti-corrosive treatments to the well. Early treatment of corrosive well conditions prevents the highly expensive and dangerous replacement of damaged well production components. Other maintenance operations in a production well environment, such as replacement of various flow control valves or the inspection of the location and condition of casing perforations, make it highly desirable for an operator located at the surface to obtain accurate, real-time information about downhole conditions.

Various techniques have been proposed for obtaining information about the conditions within a borehole, well, pipe or other tubular constructions filled with contaminated fluid with an image sensor/camera. One example is disclosed in US 14/440,261, to the applicant. This presents an inspection assembly, were a sensor cover is of a size, and adapted with a fluid, to take the place of the well fluid, enabling a single sensor to capture images of the interior of a pipe. Several further examples are found of inspection tools adapted to capture images of the interior of a well bore, either comprising a fish eye lens in the front of the tool or a camera positioned on the side.

However, even under ideal conditions these tools are only capable of capturing individual images, coupling these to depth. Further information is limited to the operator's interpretation of the images. Objective data such as size and dimensions of the damaged areas, or obstructions, may be essential information to initiate the appropriate response. Or in some cases; if it is necessary to initiate a response at all.

Therefore, there is a need for a tool and a method for capturing detailed, unobscured images of the interior of a pipe. Moreover, there is a need for a tool capable of capturing images of the interior of a pipe, for viewing by an operator.

Summary

One or more of the above objects may be achieved with an inspection assembly for inspecting the interior of a fluid filled pipe in accordance with claim 1. Further embodiments are set out in the dependent claims, in the following description and in the drawings

The inspection assembly for inspecting the interior of a fluid filled pipe, such as oil and gas wells, production and workover risers and the like, as disclosed herein comprises a sensor chamber arranged in a sensor chamber housing and a control chamber arranged in a control chamber housing. The sensor chamber and the control chamber are directly or indirectly connected to each other. The sensor chamber comprises three or more sensor assemblies, and the three or more sensor assemblies are arranged around the circumference of the sensor chamber housing in an essential helical sequence to receive sensor signals from the interior of the pipe.

The inspection assembly is preferably essentially tube-shaped and the sensor chamber housing is essentially tube-shaped with an essentially smooth outer surface.

The fact that the sensor chamber comprises three or more sensor assemblies and the three or more sensor assemblies being arranged around the circumference of the sensor chamber housing in an essential helical sequence enables an improved inspection of the fluid filled pipe. It may also enable the production of a measurable 3D model of the fluid filled pipe and thereby an improved visual inspection.

The sensor chamber may comprise four or more sensor assemblies, such as five or more sensor assemblies, such as six or more sensor assemblies. The sensor chamber may for example comprise up to ten sensor assemblies.

Optionally, the four or more sensor assemblies may be arranged around the

circumference of the sensor chamber housing such that a field of view of the sensor chamber is at least 360 degrees.

Optionally, six or more sensor assemblies may be arranged around the circumference of the sensor chamber housing such that a field of view of the sensor chamber is at least 540 degrees.

Optionally, eight or more sensor assemblies may be arranged around the circumference of the sensor chamber housing such that a field of view of the sensor chamber is at least 720 degrees.

Optionally, the sensor assemblies may be arranged around the circumference of the sensor chamber housing at essentially equal distance. Optionally, the sensor assemblies may be arranged at 0, 100, 200 and 300 degrees etc., as seen from above in the helical sequence.

Optionally, the helical sequence forms one or more helical turns, such as one and a half or more helical turns, such as two or more helical turns or such as three or more helical turns. Optionally, the sensor chamber comprises a plurality of lighting devices.

Optionally, the sensor chamber comprises at least one lighting device for each sensor assembly and wherein for each sensor assembly the at least one lighting device is arranged at an essentially opposite side of the sensor chamber housing. Optionally, the sensor chamber comprises at least two lighting devices for each sensor assembly. The fact that the sensor chamber comprises at least one lighting device for each sensor assembly and wherein for each sensor assembly the at least one lighting device is arranged at an essentially opposite side of the sensor chamber housing implies that the sensor assemblies record indirect light from the wall of the pipe. Since the surrounding fluid contains a large number of particles flowing past the camera, direct lighting is easily blocked and reflected in to the image sensor during inspection. Using indirect light minimize the risk of damaged images, and ensures an even exposure to the image sensor.

The sensor chamber and the control chamber may be connected via a chamber connecting device. Optionally, the connecting device may provide an air tight seal and thereby insulates the two chambers from each other.

The chamber connecting device may be adapted to allow for the necessary wires and cable connections for signal transmission between the two chambers when the inspection tool is assembled.

Optionally, the sensor chamber and the control chamber are at least partially thermally and mechanically sealed from each other.

Optionally, the three or more sensor assemblies each comprise an image sensor. The sensor assemblies may be image sensors comprising a camera sensor, infrared sensors, x-ray sensors, acoustic sensors and/or thermographic sensors.

The three or more sensor assemblies may be arranged in a recess provided on an outer surface of the sensor chamber housing and wherein the recesses each has a recess depth as seen from the outer surface of the sensor chamber housing, a recess opening and a recess opening edge.

The recess may furthermore have an inclined inner wall, such as an outwardly inclined inner wall.

The fact that the sensor assemblies are provided in a respective recess allows for a desired field of view of the sensor assemblies of the inspection assembly, in addition to protecting the sensor assemblies against damages and it also allows adaptation of the inspection tool for different types of sensor assemblies or lens arrangements depending on the need, without larger rebuilds on image quality.

Optionally, the recesses each have a recess angle, as measured from a centerline of the recess to opposing sides of the recess outer edge, from 30 to 230 degrees, such configuration allows for the sensor assembly arranged therein to obtain a full field of view.

The centerline of the recess may correspond to a centerline of the sensor assembly arranged therein. The recess may furthermore have an inclined inner wall, such as an outwardly inclined inner wall. The inclination angle of the inclined recess inner wall may be from 30 to 230 degrees, as measured from opposing sides of the inclined inner wall.

Optionally, the lighting devices may be arranged in recesses provided on an outer surface of the sensor chamber housing. The recesses, comprising a sensor assembly or a lighting device, may be partly or fully covered and protected by a cover. The cover may comprise an acrylic material or a sapphire crystal. The size of the covers may be adapted to at least partially cover the sensor assembly and/or the lighting device, respectively. The cover may be positioned essentially in level with the outer surface of the sensor chamber housing, or within the respective recesses.

Optionally the inspection assembly comprises a rear connection assembly being connected to the control chamber and a front connection assembly being connected to the sensor chamber housing and wherein a wire is connected to the rear connection assembly, the wire being adapted to support the weight of the inspection assembly.

Optionally the wire comprises a signal transmitting cable portion and a power

transmitting cable portion. Optionally, the sensor chamber comprises one or more passive cooling devices, such as for example heat insulating, reflecting and/or storing materials.

Optionally, the control chamber comprises one or more active cooling devices, such as for example a Peltier thermoelectric cooling unit.

Figures Figures la illustrates an inspection assembly according to the present disclosure positioned for inspection within a pipe;

Figures lb illustrates an inspection assembly according to the present disclosure;

Figure 2a illustrates a cross sectional view of the inspection assembly according to the present disclosure; Figure 2b illustrates a cross sectional view of the sensor chamber according to the present invention;

Figures 3a illustrates the housing of the sensor chamber of an inspection assembly according to an embodiment; and

Figures 3b-3c illustrate the field of view of the individual image sensors as described.

Detailed description

In the following, the embodiments herein will be discussed and example embodiments described by referring to the accompanying drawings.

The invention relates to an inspection assembly for inspection of all kinds of fluid-filled tubulars such as pipes, oil- and gas wells, production- and workover risers, BOPs etc., where visual camera or other optical or acoustic inspection methods are being performed with enhanced image quality, more particularly, to a device for enabling inspection of physical conditions within a borehole and generating data for ultimately producing a measurable 3D model. The invention may be practiced e.g. during maintenance and servicing of oil, gas, geothermal, and injection wells.

Several inspection arrangements for tubular devices like pipes, oil- and gas wells and production- and workover risers, BOPs etc. which include cameras or other forms of image sensors are known. In a typical arrangement, a tool connected to a wire is lowered into the pipe to be inspected by means of a motorized winch. For visual inspection, the probe could be a shielded camera transmitting captured images through a cable which could run through, be a part, of or constitute the wire.

The movements of the probe and the camera itself, is controlled by an operator onshore or at a rig through a user interface which also displays the images captured by the camera. Such an arrangement allows for inspection of the inner surface of the pipes and wells, as well as risers, valves and BOPs. For the purpose of simplicity, all kinds of tubular devices and arrangements like pipes, oil- and gas wells and production- and workover risers, BOPs etc. are referred to as pipes in the following description.

Figure la illustrates an example of an inspection assembly 1 for inspecting the interior of a pipe 100. A connection assembly 50 may connect the inspection assembly 1 to a weight supporting cable 51 adapted to support the weight of the inspection assembly 1. The inspection assembly 1 may be moved in relation to the pipe 100 by means of wire 51 connected through a rear connection assembly 50, as common in the art. Moreover, the wire 51 may comprise a signal transmitting cable portion (not shown) and a power transmitting cable portion (not shown), adapted to transmit signals and power to and from the inspection assembly 1.

Alternatively, the rear connection assembly 50 may connect the inspection assembly 1 to an additional downhole tool, positioning the inspection assembly 1 in a stacked fashion in a string. Likewise, a front connection assembly 30 may connect the inspection assembly 1 to an additional downhole tool, positioning the inspection assembly 1 in a stacked fashion. Alternatively, the front connection assembly 30 may be replaced with a cap 31, as illustrated in figure lb, closing the inspection assembly 1 and providing better flow of fluid over the inspection assembly 1. The inspection tool 1 is further adapted to inspect the interior of a pipe 100 having a diameter of more than 3 inches.

With further reference to figure lb, the inspection assembly 1 comprises a sensor chamber 10, comprising a sensor chamber housing 11 within which a plurality of sensor assemblies 12 is at least partially arranged. The sensor assemblies 12 being adapted to receive a sensor signal from the interior of the pipe 100 (shown in Fig. la). A sensor assembly 12 may at least comprise an image sensor with a known resolution and a lens arrangement providing a known focal length. According to one example embodiment, the image sensor may comprise a camera sensor, an infrared sensor, a thermographic sensor, an x-ray sensor, acoustic sensor or the like. In a preferred embodiment, the image sensor may be a CMOS camera chip. Each sensor assembly 12 may further be adjusted to capture images at 4-24 fps. The sensor chamber 10 is further provided with a plurality of lighting devices 13. The lighting devices 13 may be a conventional light bulb or an LED lighting source. For ease of production, the lighting device 13 may be positioned directly behind a respective sensor assembly 12, as shown in the figures. Alternatively, the lighting device may be positioned at any other position, as elaborated further herein below.

The inspection assembly 1 further comprises a control chamber 20 with a control chamber housing 21, within which the devices for operating the inspection assembly 1 is positioned. The sensor chamber 10 and control chamber 20 are connected with a connecting device 40, adjusted to connect the two assemblies 10 and 20. According to one object of the invention, the connecting device 40 also provides an air tight seal and insulates the two chambers 10,20 from each other, as well as being adapted to allow for the necessary wires and cable connections (not shown) for signal transmission between the two chambers 10,20 when the inspection assembly 1 is assembled. The sensor chamber 10 and the control chamber 20 thereby being at least partially mechanically and thermally sealed from each other. The sensor chamber 10 and control chamber 20, respectively, may be arranged to be independently removed from the rest of the inspection assembly 1. Thus, each chamber may individually be replaced, or removed for maintenance. The housings 11, 21 of the inspection assembly 1 are designed to, and provided in a material adapted to the forces and temperatures experienced in the well environment of the interior of the pipe 100.

Figure 2a shows a cross-sectional illustration of the assembly according to this disclosure. As may be seen, the control chamber 20 may, in addition to the control chamber housing 21, comprise at least a processing device 22 and a power supply 23. The processor 22 may e.g. be an FPGA processor or any other processor adjusted to process a large number of images. The inspection assembly 1, may be provided with power from the previously mentioned wire 51, connecting the assembly to a top side power source. The power supply 23 may in this embodiment be a conventional power supply unit adjusted to the requirements of supplying the devices of the inspection assembly 1. Alternatively, the power supply 23 of the inspection assembly 1 may also comprise a battery unit (not shown) capable of supplying the assembly with the required power for the duration of an inspection from a battery.

Further, the control chamber 20 may comprise a communication device 24 transmitting the recorded images and data through the previously discussed wire 51 to a topside receiver. Alternatively, the control chamber 20 may comprise a storage device, for storing the recorded images instead of transmitting them. The inspection assembly 1 may comprise further sensors, e.g. gyroscopic sensors (not showed), temperature sensors (not showed) and pressure sensors (not showed) to supply additional data to the inspection. Further sensors may be positioned and included in either the sensor chamber 10, the control chamber 20, or both. As may be observed in figure 2a and 2b, the sensor chamber housing 11 is further provided with a number of cut-outs/recesses for positioning the sensor assemblies 12.

The housing 11 is further adjusted to comprise a number of holes adapted to fit the lighting devices 13. In one embodiment of the inspection assembly 1, the lighting device 13 is positioned directly behind a corresponding sensor assembly 12, 180 degrees around the assembly relative to the sensor assembly 12. The lighting device 13 may alternatively be positioned at any other angle relative to the sensor assembly 12. Further, at least a portion of the sensor assembly 12 and the lighting device 13 may be protected by a cover 14, as may be seen in figure 2a, also enhancing flow along the side of the inspection assembly 1. The cover 14 is made of an acrylic material or a sapphire crystal, of a size adapted to at least partially cover the sensor assembly 12 and the lighting device 13, respectively. The cover 14 may be positioned in line with the housing 11, or within the cut-outs/recess.

Referring to figure 2b, the dimensions of the recess in which the sensor assembly 12 is positioned, is provided with an angle a, and a depth d. The sensor assemblies 12 have a necessary physical dimension and is provided with a known resolution, focal length and a minimum distance to which it may focus and provide sharp images of the pipe 100 (shown in Fig. la). The internal position may make it possible to adapt the inspection assembly 1 with different image sensors and lens arrangements for different scenarios, without larger rebuilds or compromising on image quality. Further, the depth d and angle a allows for a desired field of view of the sensor assembly 12 of the inspection assembly 1, a width and height of the images captured. In addition, as the flow of drilling fluid may contain particles, various debris, and be highly corrosive it is desirable to position all parts of the sensor assembly 12 within the form of the sensor chamber housing 11 to avoid unnecessary maintenance of the assembly 1.

According to one embodiment of the invention, the lens of the sensor assembly 12 may be a wide-angle lens or smaller, i.e. equivalent to a focal length smaller than 35mm for a traditional full format camera. In one preferred embodiment, the lens of the sensor assembly 12 is a so-called fish-eye lens, i.e. equivalent to a focal length smaller than

12mm for a full format camera. Further, according to one preferred embodiment, the field of view of the sensor assembly 12 may be between 60 and 180 degrees. More preferred, the field of view of the sensor assembly 12 may be between 90 and 150 degrees. Even more preferably, the field of view of the sensor assembly 12 may be between 90 and 110 degrees.

To accommodate the internal position of the sensor assembly 12 and still provide the sensor with a full field of view it is therefore necessary to provide the recess of the sensor chamber housing 11 with an angle a. According to one embodiment, the angle a may be between 30 and 120 degrees relative to a centerline of the sensor assembly 12, perpendicular to the inspection assembly 1. The angle a of the recess may decide the field of view of the sensor assembly 12, as explained. Further, the angle may not be uniform across the whole circle of the recess, but vary throughout. As with the angle a of the recess, to provide the image sensor with a full image view, the depth d is adjusted to the focal width and field of view of the lens and sensor of the sensor assembly 12.

Further, the depth d may not be same for all sensor assemblies 12, but vary between the sensors assemblies 12.

As may be seen from figure la, lb and 3a, the sensor chamber 10 is provided with a number of sensor assemblies 12 distributed and positioned in a spiral/helix pattern. The helix positions the sensor assemblies 12 in a section of the housing 11, defining an inspection area of the pipe 100. According to one embodiment, the inspection assembly 1 is provided with between 4 and 12 sensor assemblies 12. In a more preferred

embodiment, the inspection assembly 1 is provided with between 6 and 10 sensor assemblies 12 positioned in a helix. Likewise, the sensor chamber 10 is provided with a number of lighting devices 13 distributed and positioned in a spiral, helix, pattern. The helix positions the lighting devices 13 along a section of the housing 11. According to one embodiment, the inspection assembly 1 is provided with between 4 and 12 lighting devices 13. In a more preferred embodiment, the inspection assembly 1 is provided with between 6 and 10 lighting devices 12 positioned in a helix.

The height, or pitch, of the helix is in one instance decided by the image sensor characteristics, i.e. field of view as to be elaborated, but also the size of the pipe to be inspected, as to be explained hereinbelow, and the structural integrity of the inspection assembly 1. In the high-pressure environment the inspection assembly 1 may encounter, a high structural integrity is desired. Principally, it could be possible to produce the assembly with all sensor assemblies 12 positioned in one or more circles around one or more section of the body of the sensor chamber 10. This would, however, make the assembly vulnerable to increasing pressures, risking a failure during an inspection procedure. Providing a spiral with a certain pitch, distributes the pressure and mechanical stress experienced by the sensor chamber housing 11, ensuring operability and structural integrity.

Referring now to figure 3b and 3c, showing a simple example illustration of a helix seen in isometric view, and from above. According to one embodiment, the helix completes a whole circle of the inspection assembly 1. Alternatively, the helix pattern of the presented may provide a positioning of the sensor assemblies 12 of more or less than one whole revolution of the circular housing 11, distributing and positioning the sensor assemblies 12 and lighting devices 13 over more or less than 360 degrees of the inspection assembly 1. According to one aspect of the invention, the field of view of the operational sensor chamber 10 of the inspection assembly 1 is at least 360 degrees. According to a preferred embodiment, the field of view of the inspection assembly 1 is between 360 and 720 degrees, but may be as high as 1080 degrees Remembering, the earlier discussion about focal length and field of view of each sensor assemblies 12, the positioning, and number, of sensor assemblies 12 may vary, adjusted to the focal width of the sensor 12. As an example, a focal width of the sensor assembly 12 providing a field of view of 100 degrees relative to the camera will, without overlap between the images from the sensor assemblies 12, make it necessary to provide 4 sensor assemblies 12 evenly distributed around the helix of the inspection assembly 1 to acquire a full 360-degree view. As an example, and as illustrated in figure 3c, 4 sensor assemblies 12 will mean a sensor assembly 12 are positioned at 0, 100, 200 and 300 degrees, as seen from above, in the helix. This would again provide a field of view between -50 and 400 degrees.

However, in some embodiments it may be necessary to provide the sensor assemblies 12 with an overlap between the recorded images to account for distortion, adjustments and calculation to be done during processing of the recorded images, the overlap may be 1/3. Purely as an example, distortion of some fish eye lens may have effects on as much as 2/3 of an image, meaning that utilizing such a lens will involve a substantial overlap between the images, i.e. a substantially increased number of sensor assemblies 12 to acquire a 360-degree field of view of the inspection assembly 1 compared to the example above. Since the inspection tool 1 is intended to be adapted for pipes having varying pipe diameters, the pipe diameter, field of view of each sensor assembly 12, and the overlap between the images necessary, may decide the pitch of the helix pattern of the sensor chamber 11. For example, utilizing the same sensor assemblies 12 in a pipe having a smaller pipe diameter implies a narrow field of view of each sensor assembly 12, as the distance from the inner wall of the pipe 100 to the sensor assembly 12 is shorter. This in turn requires a lower pitch of the helix of the sensor chamber 11, i.e. a shorter relative vertical distance between the sensor assemblies 12, to accommodate the necessary overlap between images during inspection. Likewise, for a pipe having a larger diameter, and an identical sensor assembly 12, the accommodated field of view of the sensor assembly 12 may be larger, since the relative distance between the sensor assemblies 12 and the inner wall of the pipe 100 is larger. Thus, a helix having a greater pitch may be used, i.e. a greater vertical distance between the sensor assemblies 12, to accommodate the necessary overlap between the images of the sensor assembly 12. Of course, this may also be compensated by having a lens with an adapted width, keeping the same helix pitch.

In other words, the positioning of the sensor assembly 12 along the helical sequence is determined with regards to the desired overlap between the recorded images, which again is a function of: the field of view of each sensor assembly 12, the number of sensor assemblies 12 for each 360-degree turn and the vertical distance between each sensor assembly 12. Where distance to the inner wall of the pipe, mechanical strength of the tool and outside diameters sets the upper and lower limit for the above-mentioned inputs. Purely as an example, the necessary overlap between the recorded images in an operational inspection tool 1 may be between 10% and 40% of a captured image.

Further, as mentioned, the lighting devices 13 are positioned directly behind the sensor assemblies 12 in a corresponding helix pattern. According to one embodiment, the number of lighting devices 13 is identical to the number of sensor assemblies 12 of the assembly. Alternatively, the number of lighting devices 13 is higher than the number of sensor assemblies 12. The position of the lighting devices implies that the sensor assemblies 12 record indirect light from the wall of the pipe 100. Since the surrounding fluid contains a large number of particles flowing past the camera, direct lighting is easily blocked and reflected back to the sensor assembly 12 during inspection. Using indirect light minimize the risk of damaged images, and ensures an even exposure of the sensor assembly 12.

In an alternative embodiment, the front connection assembly 30, may be replaced with an additional front facing sensor assembly (not shown), or an additional inspection assembly 1, positioned in front or behind in a stack.

The outer dimensions of the inspection assembly may be customized with respect to the inner dimensions of the pipe to be inspected, as discussed. The above description discloses different example embodiments for illustrative purposes. A person skilled in the art would realize a variety of inspection assemblies within the scope of the appended claims.

Referring back to figure 2a, the inspection assembly 1 comprises sensor chamber 10 and a control chamber 20 being connected and insulated from each other by the connecting means 30. The sensor chamber 10 may provide a front section and the control chamber 20 may provide a rear section of the inspection assembly 1.

According to one embodiment of the invention, the sensor chamber 10 is further provided with one or more passive cooling devices 25. The control chamber 20 is according to one embodiment of the invention provided with one or more active cooling devices 26 in addition to one or more passive cooling devices 25. Both chambers 10, 20 are further shielded against the outer environment by heat isolating or storing materials placed in the cavity of the assembly. As an example, the passive cooling means may be heat insulating, reflecting and/or storing materials. In one embodiment of the presented, the housing 11 and 21, as discussed, may in addition constitute a material with heat isolating or storing capabilities, e.g. a metal with appropriate thermal capabilities. As a further example, the active cooling device 26 may comprise at least one Peltier thermoelectric cooling unit, on one side placed in contact with the heat generating components, e.g. the processing device 22. The active cooling device 26 may on the other side be in contact with material enabling heat transfer and storage, e.g. materials introduced in the assembly. In one alternative embodiment, the active cooling device 26 is placed in contact with the housing 21, i.e. a passive cooling device 25. The active cooling device 26 contribute most to the cooling, and are in this example placed so that heat is removed from the processing device 23 and stored in a passive cooling device 25.

The active cooling device 26 may e.g. be a Peltier element. A Peltier thermoelectric cooling device (thermoelectric cooling - TEC) are employed in a wide arrange of domestic products as for example in portable coolers. A Peltier thermoelectric cooling device is a solid state active heat exchanger. The cooling device is built up of at least two

semiconductors, one n-type and one p-type, that are placed in parallel to each other and joined together with a thermally conductive plate on top and below. Applying a DC current to the semiconductors creates a temperature difference, causing the side with the cooling plate to absorb heat and to move (through to) towards the side with the heat sink. The cooling ability of the total unit is in proportion to the number of semiconductors in it, and due to recent advances in the semiconductor industry, it is possible to include a sufficient number of elements in one unit to be included in an inspection assembly. A Peltier thermoelectric cooling device will typically have a maximum temperature difference of 60-70°C between the hot and cold side. The active cooling device 26 may in an alternative embodiment also be a liquid cooled element or a fan cooled element. The temperatures of the interior of a pipe her inspected can reach up to 150 degrees Celsius, and in some cases, up to 300 degrees Celsius. Positioning the active cooling device 26 in contact with the housing 21 of the chamber has shown to have an advantageous effect. This will effectively imply that the whole housing 21 becomes the heat sink of the active cooling device 26. Using the processing device 22 as an example, the active cooling device 26 cools the processor 22, transmitting heat to, effectively heating, the housing 21. As long as the temperature of the housing is lower than that of the hot side of the active cooling device 26, the contact increases heat transportation and cooling effect of the inspection assembly 1. Further, this may heat the housing 21 to a point where it reaches the well fluid temperature. At that point, the well fluid will effectively be used as heat sink and coolant of the housing, limiting a further increase in the temperature of the hot side of the active cooling device 26.

In one embodiment, the chambers of the inspection assembly 1 are further adjusted to operate under vacuum, to further increase the thermal capabilities of the inspection assembly 1.

Claims

Patent claims

1. An inspection assembly (1) for inspecting the interior of a fluid filled pipe (100), such as oil and gas wells, production and workover risers and the like, said inspection assembly (1) comprising a sensor chamber (10) arranged in a sensor chamber housing (11) and a control chamber (20) arranged in a control chamber housing (11), said sensor chamber (10) and said control chamber (20) being directly or indirectly connected to each other characterized in that said sensor chamber (10) comprises three or more sensor assemblies (12), said three or more sensor assemblies (12) being arranged around the circumference of said sensor chamber housing (11) in an essential helical sequence to receive sensor signals from the interior of said pipe (100).

2. An inspection assembly (1) according to claim 1, wherein said sensor chamber (10) comprises four or more sensor assemblies (12).

3. An inspection assembly (1) according to claim 2, wherein said four or more sensor assemblies (12) are arranged around the circumference of said sensor chamber housing (11) such that a field of view of said sensor chamber (10) is at least 360 degrees.

4. An inspection assembly (1) according to any one of claims 1-3, wherein said

sensor chamber (10) comprises a plurality of lighting devices (13).

5. An inspection assembly (1) according to claim 4, wherein said sensor chamber (10) comprises at least one lighting device (13) for each sensor assembly (12) and wherein for each sensor assembly (12) said at least one lighting device (13) is arranged at an essentially opposite side of said sensor chamber housing (11).

6. An inspection assembly (1) according to any one of the preceding claims, wherein said sensor chamber (10) and said control chamber (20) are at least partially thermally and mechanically sealed from each other.

7. An inspection assembly (1) according to any one of the preceding claims, wherein said three or more sensor assemblies (12) each comprises an image sensor, optionally said image sensor comprises a camera sensor, an infrared sensor and/or a thermographic sensor.

8. An inspection assembly (1) according to any one of the preceding claims, wherein said three or more sensor assemblies (12) each are arranged in a recess provided on an outer surface of said sensor chamber housing (11).

9. An inspection assembly (1) according to claim 8, wherein said recesses each are covered by a cover (14).

10. An inspection assembly (1) according to any one of the preceding claims, wherein said inspection assembly (1) comprises a rear connection assembly (50) being connected to said control chamber (20) and a front connection assembly (30) being connected to said sensor chamber housing (11) and wherein a wire (51) is connected to said rear connection assembly (50), said wire (51) being adapted to support the weight of said inspection assembly (1).

11. An inspection assembly (1) according to claim 10, wherein said wire (51)

comprises a signal transmitting cable portion and a power transmitting cable portion.

12. An inspection assembly (1) according to any one of the preceding claims, wherein said sensor chamber (10) comprises one or more passive cooling devices (25), such as for example heat insulating, reflecting and/or storing materials.

13. An inspection assembly (1) according to any one of the preceding claims, wherein said control chamber (20) comprises one or more active cooling devices (26), such as for example a Peltier thermoelectric cooling unit.