Tool for and method of generating a composite image of an inner portion of a conduit, and tool string

Abstract

Disclosed is a tool for generating a composite image of an inner portion of a conduit while the tool is conveyed through the conduit The tool comprises at least two image sensors arranged on the tool such that the composite image is generated by stitching a set of images resultant from each of the at least two image sensors capturing a respective image of the set of images. The tool is connectable to a tool string including at least one other tool that can transmit mechanical perturbations through the tool string to the tool and thereby cause distortions to appear in the composite image. Each of the at least two image sensors is configured to capture the respective image by measuring pixels, and the measurements of the pixels by the at least two image sensors are carried out in parallel such that the caused distortions are reduced.

Description

[0001] TOOL FOR AND METHOD OF GENERATING A COMPOSITE IMAGE OF AN INNER PORTION OF A CONDUIT, AND TOOL STRING

[0002] The present disclosure relates to a tool for generating a composite image of an inner portion of a conduit while the tool is conveyed through the conduit. The present disclosure also relates to a tool string comprising the tool. Also, the present disclosure relates to a method of generating a composite image of an inner portion of a conduit.

[0003] Background

[0004] In the drilling and production of oil and gas wells, it can be useful for an operator to obtain images captured by an inspection tool downhole. The captured images can be used for making decisions related to the operation or maintenance of the well, in many use cases. For example, captured images of equipment installed downhole, such as tubing or casing, can be used for deciding if there is a need to apply an anti-corrosion treatment, which can minimize costs and increase the effectiveness of preventing highly expensive and dangerous replacement operations for damaged well equipment.

[0005] There are known inspection tools that can capture images of an internal surface of a conduit while downhole. A known inspection tool may include a plurality of image sensors arranged relative to each other such that images captured by the image sensors may be stitched to form a composite image. For example, the image sensors may be located around a central, longitudinal axis of the inspection tool and the field of view of each of the image sensors may be selected such that the image sensors are able to cover a full 360° view of an internal surface of the conduit. The images captured by the image sensors may then be processed and stitched together to create a composite image showing the full 360° view. However, it may be challenging to generate undistorted composite images while conveying an inspection tool together with another tool that can, as a side effect of its operation, transmit mechanical perturbations to the inspection tool. This challenge may be observed when conveying the inspection tool through a conduit, such as a wellbore, by means of a tool string that includes other tools, such as a drilling tool or a running tool for setting downhole equipment. Running the inspection tool together with the other tool can be advantageous for performing inspection tasks together with other tasks efficiently. However, the other tool may transmit mechanical perturbations to the inspection tool through the tool string. The inspection tool is a sensitive equipment and submitting it to mechanical perturbations may lead to the appearance of distortions in the composite images. When conveying the inspection tool together with the other tool, various types of mechanical perturbations can be transmitted from running the tool string through a conduit and / or transmitted from the other tool to the inspection tool, such as random vibrations, sinusoidal vibrations, resonant vibrations, acoustic vibrations, torsional vibrations, simple harmonic oscillations, damped oscillations, forced oscillations, high impact shock loads, high impact impulsive loads, and torsional perturbations.

[0006] WO 2018 / 134614 Al describes a known inspection assembly including a plurality of side view cameras arranged to image different but overlapping fields of view, the plurality of cameras possibly being arranged to image a 360° annular region surrounding the inspection assembly. However, this known inspection assembly is not suitable to produce composite images that are free from distortions caused by mechanical vibrations. The last paragraph and claim 22 in WO 2018 / 134614 Al disclose that the inspection assembly may be included in a tool string having another downhole tool such as a mechanical tool. However, in practice, this approach may lead to the appearance of distortions in the composite images generated with the inspection assembly and may impose operational constraints in an operator of the tool string.

[0007] Other known approaches for stitching images to form a composite image involve dealing with distortions on the composite image by implementing corrective processing techniques of the images, such as by implementing mosaicking techniques to eliminate motion between individual images used for forming the composite image, or by implementing global motion estimation to address motion of the composite image. However, implementing corrective processing techniques can require a lot of resources and effort, require powerful processing means to be provided within the inspection tool, or make the data and processing path between the cameras and a stitched composite image difficult to optimize for efficiency. Additionally, corrective processing techniques may not be sufficient for reducing distortions caused by mechanical perturbations that would be observed when conveying an inspection tool together with another tool that can transmit mechanical perturbations to the inspection tool.

[0008] Summary

[0009] The invention will now be disclosed and has for its object to remedy or to reduce at least one of the drawbacks of the known prior art, or at least provide a useful alternative to the known prior art. The object is achieved through features, which are specified in the description below and in the claims that follow. The invention is defined by the independent patent claims, and the dependent claims define advantageous embodiments.

[0010] According to a first aspect of the invention, there is provided a tool for generating a composite image of an inner portion of a conduit while the tool is conveyed through the conduit. The tool comprises at least two image sensors arranged on the tool such that the composite image is generated by stitching a set of images resultant from each of the at least two image sensors capturing a respective image of the set of images. The tool is connectable to a tool string including at least one other tool that can transmit mechanical perturbations through the tool string to the tool and thereby cause distortions to appear in the composite image. Each of the at least two image sensors is configured to capture the respective image by measuring pixels. The measurements of the pixels by the at least two image sensors are carried out in parallel such that the caused distortions are reduced.

[0011] Thus, it is possible to significantly reduce the distortions appearing in the composite image, such that in practice these may be imperceptible to the human eye. In turn, this reduction avoids a need for carrying-out corrective processing techniques after the composite image has been generated. Also, it becomes possible to achieve faster video rates due to the lack of corrective processing techniques. Carrying out the measurements of pixels in parallel can also be advantageous in substantially increasing the simplicity of stitching the set of images to generate the composite image. Moreover, the tool makes it possible to perform inspection tasks through the conduit in a more efficient manner, given that the tool can be run together with the at least one other tool. Furthermore, the sensitivity and resolution of the image sensors can be increased while being robust against having distortions appear in the composite image due to the mechanical perturbations of the at least one other tool. Moreover, due to the measurements of the pixels being carried out in parallel, the tool may be conveyed at a higher speed through the conduit without leading to noticeable distortions appearing in the generated composite image. Thus, the tool may be used at higher conveyance speeds, and may lead to significant reductions in operational durations, effort, and cost.

[0012] Optionally, the tool further comprises: a processing unit configured to generate the composite image by stitching the set of images; a memory for storing the generated composite image; and a bus for transmitting the captured respective images from the at least two image sensors to the processing unit. Thus, the tool may be more easily integrated with the tool string, as the tool may include necessary components for generating the composite image, the tool possibly being operable in a self-contained manner. Also, the tool may be used in a set-and-forget fashion, possibly allowing composite images to be generated and stored during a trip through the conduit, which can be viewed at a later time when the tool is no longer being conveyed through the conduit.

[0013] Optionally, the bus is configured to transmit the captured images in parallel. Thus, it is possible to achieve higher transfer rates from the at least two image sensors to the processing unit.

[0014] Optionally, the processing unit is configured to control the at least two image sensors to capture the images. Thus, it is possible to achieve a finer control over when the images are captured while the processing unit performs stitching tasks.

[0015] Optionally, the tool further comprises a time determination unit, and the processing unit is configured to obtain a time measurement from the time determination unit and store, in the memory, the generated composite image together with the obtained time measurement. An example of a time determination unit may be a real-time clock, which is a well know electronic device used in computing devices for measuring the passage of time. Thus, the recorded composite image may be associated with a position within the conduit, the position being derivable, possibly at a later time, from external data related to the conveyance of the tool through the conduit.

[0016] Optionally, the tool comprises at least one joint part for forming a joint with a matching joint part provided on an adjacent component included by the tool string. Thus, the tool may be connected as part of the tool string in a non-permanent manner.

[0017] Optionally, the tool comprises two joint parts, each of the two joint parts being arranged on the tool such that the tool is providable between two components on the tool string. Thus, the tool can be provided in many positions along the tool string.

[0018] Optionally, the at least two image sensors are fixedly arranged on the tool. Thus, the tool can be used while being subjected to even stronger mechanical perturbations and under harsher conditions.

[0019] Optionally, for each of the at least two image sensors, the tool comprises a wide-angle lens. Thus, it is possible to generate the composite image having a wider field of view.

[0020] Optionally, the at least two image sensors are configured such that the composite image captures a 360° view around the tool. Thus, the tool can generate the composite image in any orientation. Also, the tool may be set to continuously generate composite images, thus possibly requiring setup actions only before and after the conveyance of the tool through the conduit with, possibly, no further actions being required while the tool is conveyed through the conduit.

[0021] Optionally, the tool further comprises a communication interface configured to connect the tool to a communication network, such that the generated composite image is transferable to a remote device. Thus, the tool can be used for providing a live feed of the generated composite image while the tool is conveyed through the conduit.

[0022] According to a second aspect of the invention, there is provided a tool string, the tool string comprising: a tool as described in the first aspect of the invention; and at least one other tool that can transmit mechanical perturbations through the tool string to the tool and thereby cause distortions to appear in the composite image.

[0023] According to a third aspect of the invention, there is provided a method of generating a composite image of an inner portion of a conduit, the method comprising the steps of: providing a tool string as described in the second aspect of the invention; and running the tool string such that the tool is conveyed through the conduit, while operating the tool to generate the composite image.

[0024] Further benefits and advantages will become apparent after a reading of the detailed description with appropriate reference to the accompanying drawings.

[0025] Brief description of the figures

[0026] In the drawings:

[0027] Fig. 1 shows a perspective view of part of a tool embodiment;

[0028] Fig. 2 shows the tool embodiment in use within a wellbore; and

[0029] Fig. 3 shows a schematic, cross-sectional view of the tool embodiment.

[0030] Detailed description

[0031] The drawings are shown in a schematic and simplified manner, and features may be left out if they are not necessary for an explanation. Identical reference numerals refer to identical or similar features in the drawings. The various features shown in the drawings may not necessarily be drawn to scale.

[0032] Fig. 1 shows a perspective view of part of a tool 100 embodiment, with the ends of the tool 100 not being shown in Fig. 1. The tool 100 is configured to form an elongated body that may be conveyed through a conduit, and the tool 100 is shown with its length aligned with the height of the page.

[0033] In the central area of Fig. 1, the tool 100 includes image sensors 110, 111 for capturing images of an inner portion of a conduit 800. The tool 100 includes a total of four image sensors 110, 111, 112, of which two are observable in Fig. 1. The four image sensors 110,

[0034] 111, 112 are arranged around a longitudinal axis through the tool 100 and on a transversal plane perpendicular to the longitudinal axis, each image sensor 110, 111, 112 being positioned such that it faces outwards.

[0035] Thus, when the tool 100 is conveyed through the conduit, the image sensors 110, 111, 112 may face an inner portion of the conduit, such as an internal surface of a casing, a pipe, or a wellbore. Thereafter, a composite image can be generated by stitching a set of images resultant from each of the image sensors 110, 111, 112 capturing a respective image for the set of images.

[0036] The volume around the tool 100 can be divided into longitudinal sectors, and the four image sensors 110, 111, 112 may be arranged at substantially ninety degrees from two other adjacent image sensors 110, 111, 112 such that each longitudinal sector is radially covered by a respective image sensor 110, 111, 112. In the tool 100 embodiment shown in Fig. 1, the composite image can show a full 360° view of the inner portion as observed around the image sensors 110, 111, 112.

[0037] Fig. 2 shows the tool 100 embodiment from Fig. 1 being conveyed through a conduit 800. In this example, the conduit is a wellbore 800. For simplicity, the wellbore 800 is illustrated in alignment with the height of the page, although, in practice, the wellbore 800 may be provided in any orientation.

[0038] The tool 100 is shown at a different orientation from the orientation shown in Fig. 1, which allows visualizing, in the central area in Fig. 2, three of the four image sensors 110, 111,

[0039] 112.

[0040] Fig. 2 shows the end of the tool string 200 including the tool 100 at the end of the tool string 100. The tool 100 is connected, on one end (seen in the upper area of Fig. 2), to one other tool 210 that is part of the tool string 200. The opposite end (seen in the bottom area of Fig. 2) of the tool 100 is disconnected. It will be appreciated that the tool string 200 may be a wireline string, coiled tubing, drill pipe or another known type of a string suitable for conveying one or more tools through a wellbore. Each end of the tool 100 includes a joint part 160, 160' for forming a joint with a matching joint part 211 provided on an adjacent component included by the tool string 200. In the example shown in Fig. 2, the tool 100 includes two joint parts 160, 160', each arranged on one respective end of the tool 100, such that the tool 100 is providable between two components on the tool string 200. Thus, the tool 100 may be provided at the end of a tool string 200, as shown in Fig. 2, or it may be provided in another position of the tool string 200, such as a position between two portions of the tool string 200.

[0041] Fig. 3 shows a cross-sectional view of the tool 100 embodiment shown in Figs. 1 and 2, which for the sake of simplicity is shown in a schematic manner.

[0042] The cross-sectional view of the tool 100 shows two of the image sensors 110, 111, 112 for capturing images of the inner portion of the conduit 800. The image sensors 110, 111, 112 are arranged on the tool 100 as shown in Figs, land 2, and each image sensor 110, 111 is provided with a wide-angle lens 170, 171, such that the composite image is generated by stitching the set of images. Examples of wide-angle lens are an ultra wide-angle lens and a fisheye lens, and the skilled person will know many other types of lenses for widening the field of view of an image sensor.

[0043] Although not shown in Fig. 3, the tool 100 is also adapted to be connected to a tool string 200 including at least one other tool 210 that can transmit mechanical perturbations through the tool string 200 to the tool 100 and thereby cause distortions to appear in the composite image.

[0044] The tool 100 is also provided such that each of the image sensors 110, 111 is configured to capture the respective image by measuring pixels, the measurements of the pixels being carried out in parallel such that the caused distortions are reduced. By "pixel", it is meant the common general meaning used for the word pixel in the field of digital imaging, such as but not limited to that a pixel may the smallest addressable element in a raster image, or the smallest addressable element in a dot matrix device. Measuring a pixel may be achieved for example but not limited to by recording a set of color levels or values, e.g. red, green, and blue, for each pixel. The tool 100 may implement a global shutter method but which is effective over the pixels measured by the two image sensors 110, 111, 112. That is, the image sensors 110, 111, 112 measure pixels in parallel. Or explained in a different manner: when one pixel is measured by an image sensor 110, 111, 112, the tool 100 is configured such that that pixel is measured in parallel to the measurements of the other pixels that are measured by the image sensors 110, 111, 112. Implementing the measurement of the pixels in parallel may be achieved by providing the image sensors 110, 110, 112 in a form equivalent to one image sensor that is configured to carry out pixel measurements distributed by the locations of the image sensors 110, 111, 112. Alternatively, some or all image sensors 110, 111, 112 may be provided as distinct electronic components that are activated in parallel, for example by a common control signal or by control signals emitted in parallel.

[0045] The tool 100 embodiment schematically shown in Fig. 3 includes: a processing unit 120 for generating a composite image by stitching the set of images; a bus 140 for transmitting the captured respective images from the image sensors 110, 120 to the processing unit 120; and a memory 130 for storing the generated composite image.

[0046] The processing unit 120 can be implemented using known electronic components suitable for generating a composite image by stitching a set of images, such as but not limited to a Field-Programmable Gate Array (FPGA), a Graphics Processing Unit (GPU), an Application- Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), a Central Processing Unit (CPU), a Vision Processing Unit (VPU), a Tensor Processing Unit (TPU), a System on a Chip (SoC), a microcontroller, or a Neural Processing Unit (NPU).

[0047] The bus 140 may be configured to transmit the captured images to the processing unit 120 in parallel. Additionally or alternatively, the bus 140 may be configured to allow the transmission of the captured images to the processing unit 120 in a multiplexing method, in which the bus 140 may be switched between the tasks of transmitting the captured image form each of the image sensors 110, 111 to the processing unit 120. One or more buffer memories may be provided for temporarily storing images captured by the image sensors 110, 111 such that the capturing of the images and the transmission to the processing unit 120 may be performed asynchronously. Stitching a set of images to form a composite image may be carried out in different ways. For example, the composite image may be generated by stitching a set of images applying digital imaging methods such as: affine transformations; perspective transformations; direct pixel-based methods such as intensity-based registration, Fourier transformations, and optical flow estimations; feature-based methods such as feature detection, feature matching, homography estimation, image warping, and blending; cylindrical projections; image re-projections; bundle adjustment refinements; graph cut methods such as seam carving identifications and graph cut optimizations. Advantageously, carrying out the measurements of pixels in parallel can also be advantageous in substantially increasing the simplicity of stitching the set of images to generate the composite image, which may make many stitching methods unnecessary.

[0048] The memory 150 may be implemented by providing memory electronic components such as but not limited to a Dynamic Random Access Memory (DRAM), a Static Random Access Memory (SRAM), a flash memory, a Double Data Rate Synchronous Dynamic Random Access Memory (DDR SDRAM), a Graphics Double Data Rate Memory (GDDR), a High Bandwidth Memory (HBM), an Non-Volatile Random Access Memory (NVRAM), a Ferroelectric Random Access Memory (FRAM), a Magnetoresistive Random Access Memory (MRAM), and a Phase-Change Memory (PCM).

[0049] In Fig. 3, the processor 120 may be connected to the image sensors 110, 111, 112 such that the processor 120 can control the image sensors 110,111, 112. In Fig. 3, a circuit path is provided connecting the processing unit 120 to both the image sensors 110, 111 shown in the cross-sectional view, which may allow the processing unit 120 to issue a common control signal for the image sensors 110, 111, 112.

[0050] The tool 100 embodiment schematically shown in Fig. 3 also includes a time determination unit 150 for generating time measurements to be stored together with the generated composite image. The processing unit 120 may obtain a time measurement from the time determination unit 150 and store, in the memory 130, the generated composite image together with the obtained time measurement.

[0051] The tool 100 embodiment schematically shown in Fig. 3 further includes a communication interface 180 for connecting the tool 100 to a communication network, such that the generated composite image can be transferred to a remote device 900. For example, the communication network may be provided through a tool string 200 as shown in Fig. 2, and the remote device 900 may be implemented as a computer being used by an operator located on topsides. The processing unit 120 may be configured to generate and transfer composite images to the remote 900 in such a manner that allows the operator to see a live video stream of the inner portion of the conduit 800.

[0052] It will be appreciated that any of the tool embodiments described above may include two or more image sensors, such as two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, or more sensors.

[0053] It will be appreciated that any of the tool embodiments described above may include at least two image sensors arranged in different ways. For example, each of the at least two sensors may be provided on different planes or on planes shared with other image sensors, each plane intersecting a longitudinal axis through the tool at a respective position and angle, in sum allowing a composite image to be generated by stitching a set of images resultant from each of the at least two image sensors capturing a respective image of the set of images.

[0054] It will be appreciated that the tool embodiments described above may be used in different types of conduits, such as but not limited to a wellbore, a pipeline (such as an oil or gas pipeline), a pipe, a tubing, a casing, a hose, a utility tunnel, a service tunnel, a concrete channel, a water main, a sewer, a culvert, an irrigation canal, a drainage pipe, a storm drain, an air duct, a ventilation shaft, a chimney, a cable conduit, a telecommunication duct, a cable tray, an exhaust pipe, or a steam pipe.

[0055] It will be appreciated that the tool embodiments described above may be provided with different known types of joint parts. For example, the joint parts may be male or female, and may be suitable to form a joint of a type such as but not limited to a threaded joint, a box and pin joint, a collet joint, a welded joint, a flange joint, a compression joint, a soldered joint, a brazed joint, a push-fit joint, a glued joint, a grooved joint, a butt fusion joint, a socket fusion joint, a press-fit joint, a grooved-end joint, and a quick-connect joint. The terms used in this description and claims are interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise. Notwithstanding, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. These terms are not interpreted to exclude the presence of other features, steps or integers. Furthermore, the indefinite article "a" or "an" is interpreted openly as introducing at least one instance of an entity, unless explicitly stated otherwise. An entity introduced by an indefinite article is not excluded from being interpreted as a plurality of the entity.

[0056] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilized for realizing the invention in diverse forms thereof.

[0057] While the invention has been described in conjunction with the embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the scope of the invention as defined in the appended claims.

Claims

C l a i m s1. A tool for generating a composite image of an inner portion of a conduit while the tool is conveyed through the conduit, wherein the tool comprises at least two image sensors arranged on the tool such that the composite image is generated by stitching a set of images resultant from each of the at least two image sensors capturing a respective image of the set of images, wherein the tool is connectable to a tool string including at least one other tool that can transmit mechanical perturbations through the tool string to the tool and thereby cause distortions to appear in the composite image, wherein each of the at least two image sensors is configured to capture the respective image by measuring pixels, and wherein the measurements of the pixels by the at least two image sensors are carried out in parallel such that the caused distortions are reduced.

2. The tool according to claim 1, wherein the tool further comprises:- a processing unit configured to generate the composite image by stitching the set of images;- a memory for storing the generated composite image; and- a bus for transmitting the captured respective images from the at least two image sensors to the processing unit.

3. The tool according to claim 2, wherein the bus is configured to transmit the captured images in parallel.

4. The tool according to any of the claims 2 to 3, wherein the processing unit is configured to control the at least two image sensors to capture the images.

5. The tool according to any of the claims 2 to 4, wherein the tool further comprises a time determination unit, and wherein the processing unit is configured to obtain a time measurement from thetime determination unit and store, in the memory, the generated composite image together with the obtained time measurement.

6. The tool according to any of the preceding claims, wherein the tool comprises at least one joint part for forming a joint with a matching joint part provided on an adjacent component included by the tool string.

7. The tool according to claim 6, wherein the tool comprises two joint parts, each of the two joint parts being arranged on the tool such that the tool is providable between two components on the tool string.

8. The tool according to any of the preceding claims, wherein the at least two image sensors are fixedly arranged on the tool.

9. The tool according to any of the preceding claims, wherein, for each of the at least two image sensors, the tool comprises a wide-angle lens.

10. The tool according to any of the preceding claims, wherein the at least two image sensors are configured such that the composite image captures a 360° view around the tool.

11. The tool according to any of the preceding claims, wherein the tool further comprises a communication interface configured to connect the tool to a communication network, such that the generated composite image is transferable to a remote device.

12. A tool string, the tool string comprising:- a tool as described in any of the claims 1 to 11; and- at least one other tool that can transmit mechanical perturbations through the tool string to the tool and thereby cause distortions to appear in the composite image.

13. A method of generating a composite image of an inner portion of a conduit, the method comprising the steps of:- providing a tool string as described in claim 12; and- running the tool string such that the tool is conveyed through the conduit, while operating the tool to generate the composite image.

Images