Robotic pigging tools

Abstract

A system includes a movable platform 100 having an uphole end and a downhole end. The platform 100 includes a drive device 110 for moving the platform in one or more directions along the inner wall 11 of a casing string in a wellbore. The platform includes a scraping device 120 for removing debris from the inner wall 11 of the casing string. The platform includes a debris collection device 130 below the wellbore of the scraping device 120 for collecting some or all of the removed debris. The platform may include a coating device 140 to transport and apply a substance to at least a portion of the wall of the casing string. The coating device may include a reservoir for containing one or more liquid substances and a valve for regulating the flow of the one or more liquid substances. The liquid substance may include an epoxy resin.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Patent Application No. 16 / 816,796, filed on March 12, 2020, entitled “Robotic Pigging Tool,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] Generally, this description relates to example techniques for oil well maintenance. Background Art

[0004] During the construction of a well (e.g., an oil or gas well), a drill string with a drill bit drills through soil, rock, and other materials to form a wellbore. The drilling process includes, among other things, pumping drilling fluid down into the wellbore and receiving flowback fluid and material from the wellbore at the surface. In order for a well to become a production well or injection well, it must be completed. Part of the well construction process includes incorporating casing and tubing into the wellbore. The casing or liner supports the sides of the wellbore and protects the components of the well from external contamination. The casing can be cemented in place with cement, and as part of the well construction process, the cement can be hardened.

[0005] One type of well is called an injection well. An injection well is a well into which fluid (e.g., gas or water) is injected rather than produced. Example purposes of injection wells typically include maintaining reservoir pressure, reducing oil viscosity, or treating oilfield water. Summary of the Invention

[0006] An example system includes a movable platform having an uphole end and a downhole end. The platform includes a drive mechanism for moving the platform in one or more directions along the inner wall of a casing string in a wellbore. The platform includes a scraping mechanism for removing debris from the inner wall of the casing string. The platform includes a debris collection mechanism below the scraping mechanism for collecting some or all of the removed debris.

[0007] The platform may include a coating device to deliver and apply a substance to at least a portion of the wall of the casing string. The coating device may include a reservoir containing one or more liquid substances and a valve to regulate the flow of the one or more liquid substances. The liquid substance may include epoxy resin.

[0008] The drive means may comprise one or more rollers. The drive means may comprise one or more continuous track wheel arrangements.

[0009] The scraping device may include one or more brushes for scraping debris from the wall of the casing string. The one or more brushes may be stationary relative to the platform. The one or more brushes rotate to remove debris from the wall of the casing string. The scraping device may include one or more blades for scraping debris from the wall of the casing string.

[0010] The debris collection arrangement may be at least partially magnetic.The debris collection arrangement may comprise an electromagnetic device.

[0011] The system may include a plug located downhole on the platform for sealing the lumen of the casing. The plug may be removable.

[0012] The system may include a power source in electrical communication with the platform to provide power to one or more components of the platform.

[0013] The system may include a control unit in data communication with the platform to control one or more components of the platform.

[0014] An exemplary method for corrosion repair of a casing string in a wellbore includes driving a movable platform having an uphole end and a downhole end along the inner wall of at least a first portion of the casing. The platform includes a driving device, a scraping device, a debris collection device below the wellbore of the scraping device, and a coating device. The method includes removing debris from the inner wall of the casing string by the scraping device. The method includes collecting at least some of the removed debris by the debris collection device. The method includes coating at least a second portion of the casing with one or more liquids using the coating device.

[0015] The method may include deploying a plug downhole of at least a first portion of the casing string to seal the lumen of the casing string. The method may include mixing two or more liquids prior to coating. The method may include driving the platform in a downhole direction during scraping and in an uphole direction during coating.

[0016] Any two or more features described in this specification (including in this Summary) can be combined to form embodiments not specifically described in this specification.

[0017] All or part of the processes, methods, systems, and techniques described in this specification can be controlled by executing instructions stored on one or more non-transitory machine-readable storage media on one or more processing devices. Examples of non-transitory machine-readable storage media include read-only memory, optical disk drives, memory disk drives, random access memory, and the like. All or part of the processes, methods, systems, and techniques described in this specification can be controlled using a computing system that includes one or more processing devices and a memory storing instructions executable by the one or more processing devices to perform various control operations.

[0018] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is an example wellbore servicing system in a wellbore as described herein.

[0020] Figures 2A to 2D is an example wellbore servicing system as described herein during operations in a wellbore. DETAILED DESCRIPTION

[0021] This specification describes techniques for maintaining or repairing casing (including liners) or tubing in wellbores in oil or gas fields. Casing or tubing that can be maintained using the techniques described herein include casing or liners in production wells (wells used to extract hydrocarbons from hydrocarbon formations) or injection wells (wells used to inject fluids into formations). These techniques can be used to remove scale and sediment from the casing or tubing. These techniques can also be used to inspect the casing or tubing, for example, to detect metal loss due to corrosion or to inspect the integrity of the casing or tubing. These techniques can also be used to maintain or repair the casing or tubing, for example, to seal defects in the casing or tubing.

[0022] Corrosion is often associated with the operation of wells (e.g., injection wells). Corrosion in a well may be characterized by the loss of casing or tubing material (e.g., metal) caused by chemical or electrochemical reactions. In some cases, the corrosion may be so severe that the casing or tubing may be perforated, which may result in damage to the casing or tubing structure. In some cases, the corrosion in the casing or tubing may be so severe that a casing-casing annulus (CCA) may be formed between two casing or tubing sections. For example, two casing or tubing sections may be connected by concentrically overlapping the distal end of a first casing or tubing section with the proximal end of a second casing or tubing section. The first and second tubing sections may be joined, for example, by crimping or by a cement layer that can form a fluid seal. In some cases, corrosion may affect the cement layer or may affect the first or second tubing section, causing the fluid seal to be at least partially destroyed. Wellbore fluid may enter the casing or tubing, potentially leading to contamination or other undesirable fluid communication between geological formations. The injected fluid may leave the injection well at an undesirable location, potentially leading to contamination.

[0023] Corrosion rates can vary over time, depending on site-specific conditions and the type of chemical exposure. Factors include the amount or flow rate of produced or injected water, pressure variations, the chemical composition of the produced or injected fluid, and the temperature of the fluid, casing, or tubing. Detecting and repairing corrosion in casing or liner can be critical to well operations and safety.

[0024] During well (e.g., injection well) operations, solid deposits may form on the inner surface of the casing or tubing. Such deposits may include corrosion-related deposits (e.g., rust) or may include other types of solids (including wax, scale, and debris). Detection and removal of deposits in the casing or liner can be critical to the efficiency and effectiveness of oil well operations.

[0025] Figure 1An example system for performing maintenance or repair on casing (including liner) or tubing in a wellbore of an oil or gas well is shown. The example system can include a movable platform 100 having an uphole (proximal) end and a downhole (distal) end. The platform 100 can be deployed in the inner cavity 12 of an example casing string 10 of a wellbore located in a rock formation 15. The platform 100 can include a drive device 110 for moving the platform 100 in one or more directions, for example, along the inner wall 11 of the casing string 10. The platform 100 can include one or more scraping devices 120 for removing debris from the inner wall 11 of the casing string 10. The platform 100 can include one or more debris collection devices 130 for collecting debris (e.g., some or all of the debris removed by the scraping devices 120). In some embodiments, the platform 100 can include a coating device 140, for example, to deliver or apply a substance, or both, to at least a portion of the wall 11 of the casing string 10.

[0026] The example platform 100 may include an example drive assembly 110, which may include one or more devices for transporting the platform 100 in one or more directions. In some embodiments, the drive assembly 110 may include one or more rollers 111. The one or more rollers 111 may be connected to one or more motors (e.g., one or more electric motors). In some embodiments, the one or more rollers 111 may be connected to a steering assembly, such as a rack and pinion assembly. Thus, the one or more wheels may be steerable by rotating the one or more rollers about an axis perpendicular to the roller's axis of rotation. The steering assembly may be actuated by one or more motors (e.g., electric motors), or by hydraulic or pneumatic means. In some embodiments, the one or more rollers 111 may be arranged such that controlling or varying the rotational speed of the one or more rollers can steer the platform 100. In one example embodiment, the one or more rollers may be positioned on a first side (e.g., the left side) of the platform 100 when viewed from the uphole (proximal) end along its longitudinal axis. The one or more rollers may be positioned on a second side (e.g., the right side) of the platform 100. Rotating all rollers at the same speed can move the platform 100 along the longitudinal axis of the platform 100. Reducing the rotational speed of one or more rollers on a first side (e.g., the left side) can cause the platform to rotate in a first direction (e.g., the left direction). In some embodiments, the drive assembly 110 can include one or more continuous track wheel assemblies (crawler assemblies). In some embodiments, the rotational speed of one or more rollers or the exemplary steering mechanism can be controlled by an electronic control unit (e.g., control unit 400).

[0027] The example platform 100 may include an example scraping device 120 for removing debris from the inner wall 11 of the casing string 10. The example scraping device 120 may include one or more scraping tools, such as one or more brushes, blades, drill bits, grinders, lasers, or hammers. In some embodiments, the example scraping device 120 may include one or more brushes for brushing debris from the wall of the casing string. In some embodiments, during the scraping operation, the one or more brushes may be stationary relative to the platform 100. In some embodiments, the one or more brushes may rotate to remove debris from the wall of the casing string. In an example embodiment, the one or more rotating brushes may be rotated via a mechanism that connects the one or more brushes to one or more rollers of the drive device 110. For example, the same mechanism that drives the one or more rollers of the drive device 110 (e.g., a mechanism including an electric motor) may cause the rotation of the one or more brushes of the example scraping device 120. In one example embodiment, one or more brushes of the example scraping device 120 can be rotated by a mechanism including one or more motors (e.g., electric motors) that are not used to drive the rollers of the drive device 110. The one or more brushes of the example scraping device 120 can include steel bristles or polymer bristles or other such tools.

[0028] In some embodiments, the example scraping device 120 may include one or more blades for scraping debris from the wall of the casing string. In some embodiments, the one or more blades of the example scraping device 120 may be movable, such as rotatable, such as rotatable about an axis substantially parallel to the cutting edge of the blade. For example, the same mechanism that drives the one or more rollers of the drive device 110 (e.g., a mechanism including an electric motor) can cause the one or more blades of the example scraping device 120 to rotate. In one example embodiment, the one or more blades of the example scraping device 120 can be rotated by a mechanism including one or more motors (e.g., electric motors) that are not used to drive the rollers of the drive device 110.

[0029] In some embodiments, the example scraping device 120 can include one or more scraping tools (e.g., one or more brushes or blades) that can be coupled to a deployment mechanism mounted on or as part of the platform 100. In some embodiments, the example deployment mechanism (e.g., a set of movable rods) can have a first configuration, such as a retracted configuration, in which the one or more scraping tools do not extend to or substantially contact the wall 11 of the cannula 10. In some embodiments, the example deployment mechanism can have a second configuration, such as an extended configuration, in which the one or more scraping tools extend to or substantially contact the wall 11 of the cannula 10 (e.g., to perform a scraping operation). The example deployment mechanism of the scraping device 120 can be actuated by one or more motors (e.g., one or more electric motors), or by hydraulic or pneumatic means. Actuation can cause the example mechanism to move from a first, retracted configuration to a second, extended configuration, or vice versa. In some embodiments, the scraping device 120 can be adjustable to accommodate cannulas 10 of varying diameters. In some embodiments, the scraping device may include an adjustment mechanism (e.g., a mechanism including a spring and a damper coupled to the one or more scraping tools and coupled to one or more other components of the platform 100) that maintains contact between the scraping tools and the wall 11. In some embodiments, the adjustment mechanism and the deployment mechanism may be combined. In some embodiments, the deployment or movement of the one or more scraping tools may be controlled by an electronic control unit (e.g., the control unit 400).

[0030] The example platform 100 can include an example debris collection device 130 for collecting debris (e.g., some or all of the debris removed by the scraping device 120). The example debris collection device can include one or more screens, nets, meshes, or wires. In some embodiments, the debris collection device 130 can be or include one or more magnetic components. In some embodiments, the debris collection device 130 can include one or more electromagnetic devices connected to a power source. In some embodiments, activation of the one or more electromagnetic devices of the one or more collection tools can be controlled by an electronic control unit (e.g., control unit 400).

[0031] In some embodiments, the example debris collection device 120 may include one or more collection tools (e.g., one or more screens, nets, meshes, or wires) that may be coupled to a deployment mechanism mounted on or as part of the platform 100. In some embodiments, the example deployment mechanism (e.g., a set of movable rods) may have a first configuration, such as a retracted configuration, in which the one or more collection tools do not extend to or substantially contact the wall 11 of the casing 10. In some embodiments, the example deployment mechanism may have a second configuration, such as an extended configuration, in which the one or more collection tools extend to or substantially contact the wall 11 of the casing 10 (e.g., to collect debris removed from the wall 11). The example deployment mechanism of the debris collection device 130 may be actuated by one or more motors (e.g., one or more electric motors), or by hydraulic or pneumatic means. Actuation may cause the example deployment mechanism to move from a first, retracted configuration to a second, extended configuration, or vice versa. In some embodiments, the deployment or movement of the one or more collection tools may be controlled by an electronic control unit (e.g., control unit 400).

[0032] The example platform 100 may include an example coating device 140, for example, to deliver or apply or deliver and apply a substance to at least a portion of the wall 11 of the casing string 10. In some embodiments, the coating device 140 may include one or more reservoirs for containing one or more liquid substances. The liquid substances used using the technology described in this specification may include paint, glue, polymer, epoxy resin, epoxy hardener, or a combination thereof. In some embodiments, the coating device 140 may include one or more valves to regulate the flow of liquid substances, such as out of one or more reservoirs. In some embodiments, the actuation of the one or more valves may be controlled by an electronic control unit (e.g., control unit 400). The coating device 140 may include one or more nozzles that are fluidly connected to the one or more reservoirs via a conduit to apply the one or more liquid substances to the surface of the wall 11. In some embodiments, the one or more nozzles may include a mixing device to mix the two or more liquids before applying them to the wall 11, for example, mixing epoxy resin and epoxy hardener.

[0033] In some embodiments, the example coating device 140 may include one or more coating tools (e.g., one or more applicators or nozzles connected to one or more fluid reservoirs via conduits). The one or more applicators may be connected to a deployment mechanism mounted on or as part of the platform 100. In some embodiments, the example deployment mechanism (e.g., a set of movable rods) may have a first configuration, such as a retracted configuration, in which the one or more coating tools do not extend to or substantially contact the wall 11 of the cannula 10. In some embodiments, the example deployment mechanism may have a second configuration, such as an extended configuration, in which the one or more coating tools extend to or substantially contact the wall 11 of the cannula 10 (e.g., to apply one or more liquids to the wall 11). The example deployment mechanism of the coating device 140 may be actuated by one or more motors (e.g., one or more electric motors), or by hydraulic or pneumatic means. Actuation may cause the example deployment mechanism to move from a first, retracted configuration to a second, extended configuration, or vice versa. In some embodiments, the deployment of the one or more coating tools may be controlled by an electronic control unit (e.g., control unit 400). The example reservoir can be pressurized. In some embodiments, one or more pumps can be arranged to be fluidically connected to the one or more reservoirs such that activation of the one or more pumps causes fluid to flow from the one or more reservoirs through the conduits and out of the one or more nozzles. In some embodiments, the pumping operation can be controlled by an electronic control unit (e.g., control unit 400). The coating device 140 can move independently of the remaining components of the platform 100. In some embodiments, the coating device 140 (e.g., a deployment mechanism of the coating device 140) can rotate or translate about one or more axes.

[0034] In some embodiments, the system may include a plug 200 positionable below the platform well to seal the lumen 12 of the casing 10, e.g. Figure 1 As shown. In some embodiments, the plug 200 can be removable or retractable. In some embodiments, the plug 200 can include an expandable or inflatable element that can be moved downhole and inflated in situ, for example, via a wireline operation. In some embodiments, the plug can be or can include one or more screens, nets, meshes, or wires that can be connected to a deployment mechanism. In some embodiments, the plug 200 can be non-retractable after the scraping operation, but rather configured to remain in the casing string 10. After the scraping or coating operation is completed, a drill bit or other tool can be used to drill through or otherwise destroy the plug 200.

[0035] In some embodiments, the example system may include a power source. The example power source may be or may include a power source, such as a generator 300. In some embodiments, the example power source (e.g., generator 300) may be located on the surface 25 outside the wellbore and casing string 10. Power may be transmitted from the power source (e.g., generator 300) to the platform 100 via one or more power cables. The one or more power cables may be integrated into the wireline 190. In some embodiments, the power source may be a downhole generator, for example, a generator powered by the movement of fluid through a set of turbine blades connected to the downhole generator. In some embodiments, the power source may be part of the platform 100. In some example embodiments, the power source as part of the platform 100 may include one or more batteries.

[0036] In some embodiments, the example system may include a control unit 400. The example control unit 400 may be or may include one or more processors and one or more data storage media. In some embodiments, the example control unit 400 may be located on the surface 25 outside the wellbore and casing string 10. Data may be exchanged between the example control unit 400 and the platform 100 via one or more data links (e.g., one or more data cables). The one or more data cables may be integrated into the wireline 190. In some embodiments, one or more components or all components of the control unit 400 may be part of the platform 100.

[0037] In some embodiments, the example system may include one or more sensors, for example, one or more sensors attached to or otherwise integrated into the platform 100. In some embodiments, the one or more sensors include one or more of a temperature sensor, a pressure transducer, a gyroscope, a camera, or a laser. In some embodiments, the system may include a set of sensors (e.g., an ultrasonic transducer), for example, to map the area around the platform 100. In some embodiments, one or more rollers of the drive device 110 may be equipped with a speed measurement device to follow the progress of the platform 100 during movement. A control system (e.g., control system 400) may monitor the actual speed compared to the commanded speed, for example, to determine whether the platform 100 is moving unimpeded or at risk of getting stuck. In some embodiments, the systems described herein may be guided by an operator, for example, interacting with the control system 400. In some embodiments, the systems described herein may operate fully or partially autonomously, for example, as a robotic platform.

[0038] exist Figures 2A to 2DIn some embodiments, prior to the scraping operation, a plug 200 may be deployed on a delivery string 201 in the casing string 10, downhole (distal) to one or more areas of corrosion or debris accumulation on the wall 11 ( Figure 2A ). Areas of corrosion or debris accumulation may have been previously detected using, for example, a system described herein (e.g., one or more sensors on the platform 100). In some embodiments, the plug 200 may include an expandable or inflatable element that can be deflated or inflated during transport from the surface 25 to the target location. Once in the target location, the expandable or inflatable element of the plug 200 can be expanded or inflated to secure the plug 200 in place, such as by pumping a fluid into the expandable element so that the expandable element at least partially contacts the wall 11 to secure the plug 200. In some embodiments, one or more screens, nets, meshes, or wires can be deployed as part of the plug 200. In some embodiments, the expandable element or one or more screens, nets, meshes, or wires, or a combination thereof, can completely seal the inner cavity 12 of the casing 10. After the plug 200 is deployed, the delivery string can be retrieved uphole.

[0039] In some embodiments, the platform 100 can be lowered into the lumen 12 of the casing string 10, for example, via a wireline operation, e.g., into or near an area of ​​corrosion or debris accumulation. In some embodiments, the platform 100 can be self-propelled, for example, by one or more rollers in contact with the wall 11 of the casing string 10, and can be driven into or through an area of ​​corrosion or debris accumulation (e.g., see FIG. Figure 2B). The arrival of the platform 100 at or near an area of ​​corrosion or debris accumulation may be indicated, for example, by one or more optical sensors (e.g., one or more cameras) directed toward the wall 11 and transmitting image data to a control system (e.g., control system 400). In some embodiments, a user operating the control system 400 may deploy the one or more debris collection devices 130 and the one or more scraping devices 120. In some embodiments, for example, in robotic embodiments of the systems described herein, the control system 400 may cause the one or more debris collection devices 130 and the one or more scraping devices 120 to be deployed without user interaction. In some embodiments, the deployment of the one or more scraping devices 120 includes contacting the wall 11 with one or more scraping tools. In some embodiments, the movement of the platform 100 down the well may cause the one or more scraping tools to contact the wall 11 and remove debris from the wall 11. In some embodiments, the movement of the platform 100 up the well may cause the one or more scraping tools to contact the wall 11 and remove debris from the wall 11. In some embodiments, scraping may occur or may be at least partially assisted by the movement of the one or more scraping tools independently of the movement of the platform 100. In example embodiments, one or more scraping tools may be or include rotating brushes or blades that contact and remove debris from the wall 11. Debris removed from the wall 11 may be collected by one or more debris collection devices 130. In some embodiments, such as in a vertical well, the debris collection device 130 may be located below (distal to) the scraping device 120 and may, for example, use one or more screens, meshes, nets, or wires to collect falling debris. Debris (e.g., debris resulting from corrosion-induced iron accumulation) may be ferromagnetic. In some embodiments, the debris collection device 130 may be or include one or more magnetic components, such as one or more electromagnetic components or devices (e.g., meshes or screens) connected to an electronic power source. In some embodiments, during the scraping operation, the electromagnetic components may be energized, which may cause debris to adhere to the one or more electromagnetic components. In some embodiments, the debris collection device 130 may remain deployed during retrieval of the platform 100 (movement of the platform 100 upwards into the well) to extract the collected debris from the casing string 10. In some embodiments, the debris collection device 130 may be retracted during retrieval (movement of the platform 100 up the well) of the platform 100. Debris not collected by the debris collection device 130 may be collected by the plug 200.

[0040] After the scraping operation is completed, one or more defects (e.g., holes or cracks) may exist in the wall 11 of the sleeve 10. In some embodiments, a user operating the control system can deploy one or more coating devices 140. In some embodiments, for example, in a robotic embodiment of the system as described herein, the control system 400 can cause the one or more coating devices 140 to be deployed without user interaction. In some embodiments, one or more coating tools (e.g., one or more applicators or nozzles connected via conduits to one or more reservoirs containing one or more fluids) can be deployed in contact with or placed near the wall 11. The fluid (e.g., a liquid coating, such as an epoxy and a hardener) can be pumped from the one or more reservoirs through the one or more nozzles and applied to the wall 11. In some embodiments, during the pumping process, for example, by rotating or translating the coating device 140 or a portion thereof, or by translating the platform 100 to move the one or more nozzles, can cause an area of ​​the wall 11 to be coated, for example, uniformly coated. In some embodiments, the coating quality can be assessed, for example, by visual inspection using one or more optical sensors mounted on the platform 100.

[0041] After the scraping or coating procedure is completed, the lumen 12 of the casing string 10 can be reopened, for example, by removing the plug 200. Figure 2D In some embodiments, a retrieval string can be lowered downhole and connected to the plug 200. In some embodiments, the inflated inflatable element can be deflated or the inflatable element can be retracted. The plug 200 can then be retrieved and moved uphole, for example, using the retrieval string 202. In some embodiments, the plug 200 may not be retrieved after the scraping operation, but may instead remain in the casing string 10. After the scraping or coating operation is completed, a drill bit or other tool can be used to drill through or otherwise destroy the plug 200.

[0042] It should be understood that the operations described herein may be performed in vertical or horizontal wells.

[0043] At least a portion of the system described in this specification and various modifications thereof can be controlled by a computer program product (e.g., a computer program tangibly embodied in one or more information-forming carriers). The information carriers include one or more tangible, machine-readable storage media. The computer program product can be executed by a data processing device. The data processing device can be a programmable processor, a computer, or multiple computers.

[0044] A computer program can be written in any form of programming language, including compiled or interpreted languages. A computer program can be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program can be deployed to execute on one computer or on multiple computers. The computer or computers can be located at one site or distributed across multiple sites and interconnected via a network.

[0045] The actions associated with implementing the system can be performed by one or more programmable processors executing one or more computer programs. All or part of the system can be implemented as a dedicated logic circuit, such as a field programmable gate array (FPGA) or an ASIC application specific integrated circuit (ASIC), or both.

[0046] Processors suitable for executing computer programs include, for example, general-purpose and special-purpose microprocessors, and include any one or more processors of any type of digital computer. Typically, a processor will receive instructions and data from a read-only memory area, a random access memory area, or both. Components of a computer (including a server) include one or more processors for executing instructions and one or more storage area devices for storing instructions and data. Typically, a computer will also include one or more machine-readable storage media, or will be operably connected to receive data from or transfer data to one or more machine-readable storage media, or both. Machine-readable storage media include mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks. Non-transitory machine-readable storage media suitable for containing computer program instructions and data include all forms of non-volatile storage areas. Non-transitory machine-readable storage media include, for example, semiconductor storage area devices, such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and flash memory area devices. Non-transitory machine-readable storage media include, for example, magnetic disks, such as internal hard disks or removable disks, magneto-optical disks, and CD-ROM and DVD-ROM disks.

[0047] Each computing device may include a hard drive for storing data and computer programs, a processing device (eg, a microprocessor), and memory (eg, RAM) for executing computer programs.

[0048] Components of the different embodiments described in this specification may be combined to form other embodiments not specifically described in this specification. Components may be omitted from the system without adversely affecting the operation of the system described in this specification.

Claims

1. A system for repairing corrosion in a casing string in a wellbore, comprising: A movable platform having an uphole end and a downhole end, the platform comprising: a driving device for moving the platform in one or more directions along the inner wall of the casing string in the wellbore; a scraping device for removing debris from the inner wall of the casing string; and a debris collection device below the well of the scraping device for collecting some or all of the removed debris, wherein the debris collection apparatus comprises an electromagnetic device for collecting some or all of the removed debris, wherein the electromagnetic device comprises at least one of a mesh and a screen for collecting some or all of the removed debris, and wherein energizing the electromagnetic device causes some or all of the removed debris to adhere to at least one of the mesh and the screen, and wherein the scraping device comprises one or more scraping tools, wherein the one or more scraping tools are connected to a set of movable rods that are capable of being extended to substantially contact the inner wall of the casing string, wherein the scraping device comprises a pneumatic device for extending the movable rods, and wherein the scraping device comprises an adjustment mechanism for the scraping device, wherein the adjustment mechanism comprises a spring and a damper.

2. The system according to claim 1, wherein: The platform includes an applicator device downhole of the debris collection device to deliver and apply a substance to at least a portion of the wall of the casing string.

3. The system according to claim 2, wherein: The coating device includes a reservoir containing one or more liquid substances and a valve for regulating the flow of the one or more liquid substances out of the reservoir.

4. The system according to claim 3, wherein: The liquid substance includes epoxy resin.

5. The system according to claim 1, wherein The drive means comprises one or more rollers, wherein one or more of the one or more rollers are equipped with a speed measuring device to follow the travel of the platform.

6. The system according to claim 1, wherein: The driving device includes one or more continuous track wheel devices, and each of the continuous track wheel devices is a crawler type device.

7. The system according to claim 1, wherein: The one or more scraping tools are one or more brushes for brushing debris from the wall of the casing string.

8. The system according to claim 7, wherein: The one or more brushes are stationary relative to the platform.

9. The system according to claim 7, wherein: The one or more brushes rotate to remove debris from the wall of the casing string, and The one or more brushes are rotated via a mechanism connecting the one or more brushes to one or more rollers of the drive device.

10. The system according to claim 1, wherein: The one or more scraping tools are one or more blades for scraping debris from the wall of the casing string.

11. The system according to claim 5, wherein: The debris collection device is at least partially magnetic.

12. The system of claim 1, comprising a plug located downhole at the platform for sealing the lumen of the casing.

13. The system according to claim 12, wherein: The plug is removable, wherein the plug includes an expandable element that is expanded by pumping a fluid into the expandable element to secure the plug in place, and wherein the plug is drillable.

14. The system of claim 1 , comprising a power source in electrical communication with the platform to provide power to one or more components of the platform, in, The removed debris includes ferromagnetic material.

15. The system of claim 1 , comprising a control unit in data communication with the platform to control one or more components of the platform. in, The debris collection device is configured to retract during retraction of the movable platform, and The retraction of the movable platform includes the movement of the movable platform upwards into the well.

16. The system of claim 3, wherein the coating device comprises one or more nozzles fluidly connected to the reservoir via a conduit to apply one or more liquid substances to the inner wall of the casing string, in, The one or more liquid substances include an epoxy resin and an epoxy hardener, and wherein the reservoir is pressurized.

17. The system according to claim 16, wherein: Each of the one or more nozzles includes a mixing device to mix the epoxy resin and the epoxy hardener.

18. A method for repairing corrosion in a casing string in a wellbore, the method comprising: A movable platform having an uphole end and a downhole end is driven along an inner wall of at least a first portion of the casing, the platform comprising: Drive device; scraping device; a debris collection device below the well of the scraping device, wherein the debris collection device includes an electromagnetic device for collecting debris, wherein the electromagnetic device includes at least one of a mesh and a screen for collecting debris; and coating device; removing debris from the inner wall of the casing string by the scraping device; collecting at least some of the removed debris with the debris collection device, wherein collecting the removed debris includes energizing the electromagnetic device to cause the removed debris to adhere to at least one of the mesh and the screen; mixing two or more liquids prior to coating by the coating device, wherein the two or more liquids include an epoxy resin and an epoxy hardener; coating an inner wall of at least a second portion of the sleeve with the mixture of the two or more liquids using the coating device; and driving the platform in a downhole direction during scraping and in an uphole direction during coating, Wherein, the platform includes a set of ultrasonic transducers, and the method includes using the set of ultrasonic transducers to map an area around the platform.

19. The method of claim 18, comprising deploying a plug downhole of at least the first portion to seal the lumen of the casing string.

20. The method according to claim 19, wherein The plug includes an expandable element, and wherein the expandable element of the plug is expanded by pumping a fluid into the expandable element.

21. The method according to claim 20, wherein The coating device includes a reservoir for containing one or more liquid substances and a valve for regulating the flow of the one or more liquid substances out of the reservoir.

22. The method according to claim 21, wherein The method includes operating the system completely or partially autonomously.

23. The method according to claim 22, wherein The drive arrangement comprises one or more rollers, wherein at least one of the one or more rollers is equipped with a speed measuring device to follow the travel of the platform, and wherein the method comprises monitoring the speed of the platform using the speed measuring device.

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