EP3935257B1

EP3935257B1 - Cut measurement method and associated apparatus

Info

Publication number: EP3935257B1
Application number: EP20713073.3A
Authority: EP
Inventors: John Stoddard; Craig Baxter; David Macwilliam
Original assignee: Claxton Engineering Services Ltd
Current assignee: Claxton Engineering Services Ltd
Priority date: 2019-03-05
Filing date: 2020-03-04
Publication date: 2024-05-15
Anticipated expiration: 2040-03-04
Also published as: GB2582267A; GB2582267B; EP3935257A1; GB202105764D0; GB2591700A; GB201902959D0; GB2591700B; WO2020178577A1

Description

FIELD

This disclosure relates to a measurement system and method for measuring cuts made by a cutting tool. The system and method can optionally, and not exclusively, applied to retrieval operations for infrastructure abandonment operations such as well infrastructure abandonment operations, or the like.

BACKGROUND

Oil and gas wells that have come to the end of their productive life require to be abandoned. Similarly, piles, pipes, conductors and other onshore and offshore assets and infrastructure may also need to be decommissioned at the end of their operational life.
In the North Sea, as well as in other hydrocarbon-producing areas of the world, owners of aging assets are under a legal obligation to decommission wells to avoid or mitigate any environmental impact that the well may have on its surrounding environment. Decommissioning represents a significant financial liability to owners of these assets.
In an example well abandonment operation, a cutting tool is introduced into the inner casing to a location below the surface, for example, 10 m below the surface. The cutting tool is used to cut through the casing until an upper portion of the casing is severed from a lower portion of the casing. In certain examples, the casing may include a multiple casing string to be severed in a single cutting operation. It will be appreciated that such casing may include conductor, liner, or other such tubing that may have been deployed at the well site. Such multi-casing structures may have multiple annuli, which may in some examples be filled with cement, or the like. In any event, once the casing has been completely severed, a pulling tool may be used to retrieve the upper portion of the casing from the well for disposal. Upon removal of the upper portion, the region where the upper portion was previous positioned may be filled with cement or other appropriate material to fully decommission the well.
Examples of cutting tools as outlined in the preamble of claim 1 can be found in WO 2016/123166 , WO 2015/088553 , WO 2013/019959 , US 2014/138083 or US 2008/166132 .
It may be difficult to verify if all casings have been completely severed in a cutting operation. An example method of verifying whether the casing has been completely severed is by using a pulling tool such as a crane, winch or hydraulic ram to pull on the casing and physically retrieve the severed portion from the well under tension. This method may not always be available due to limited crane capacity, deck space and/or time. In some examples, the success or failure of the cutting operation may not be verified until removal of the casing which can take place weeks, months or even years after the cutting operation. This can result in unwanted down time for the pulling tool, which may be comprised in a heavy lift vessel or rig, which may have a significant associated cost. If the casing was not cut properly in the first instance, a well cutting tool may need to be re-deployed to carry out a second cutting operation resulting in additional time and cost.

SUMMARY

Described herein is a cutting system with at least one cutting tool and a measurement system for measuring a cut in a tubular or other member. The measurement system may be configured for motion, e.g. rotational or linear motion, e.g. with a rotating or movement head of a cutting system. The measurement system is configured to determine an extent, progress and/or geometry of a cut in a wall of the tubular or other member.
The measurement system may be coupled to or mounted on the rotating or movement head.
The measurement system may configured to distinguish a cut partially through the wall of the tubular from a cut wholly through the wall of the tubular or other member. The cut may be intended to be a cut wholly through the wall of the tubular (e.g. a full depth cut) or other member. For example, the cut may be a cut from an interior of the tubular or other member to an exterior of the tubular. The measurement system may be configured to identify an undesirable situation in which the cut may be partially through the wall of the tubular or other member (e.g. a partial depth cut), such as a cut from an interior surface of the wall of the tubular to a closed end of the cut embedded within the wall of the tubular or other member.
The measurement system may be configured to determine positions of points on a surface (e.g. a surface of the cut in the wall of the tubular or other member, such as a surface of the cut that extends through the depth of the cut, and/or at least part of a surface of a wall of the tubular adjacent to the cut) relative to the measurement system, e.g. indicative of a distance and angle from the measurement system to the points on the surface. The measurement system may be configured to collect data representing a 3D image or model of the cut in the wall of the tubular or other member and/or at least part the wall of the tubular or other member. The measurement system may be configured to use the determined positions of the points on a surface to construct the 3D model or image. The measurement system may be configured to determine the geometry and/or extent or progress of the cut from the 3D image or model. The measurement system may be configured to map and/or create a profile of the cut through the depth of the cut, e.g. from one end of the cut to another. The extent of the cut may be a depth of the cut into the wall of the tubular, e.g. from an interior surface of the tubular or other member. The measurement system may be configured to determine if the cut extends part of the way through the wall of the tubular or all of the way through the tubular or other member.
The measurement system may be, comprise or be comprised in a laser scanner, such as a 3D laser scanner. The laser scanner may comprise at least one laser unit configured to emit, e.g. sweep, one or more laser beams. The laser scanner may comprise at least one detector configured to receive the at least one laser beam after being reflected or scattered from a surface. The at least one detector may be configured to provide a signal indicative of the received laser beam(s). The signal provided by the at least one receiver may be indicative of the positions of points on the surface relative to the laser scanner, e.g. indicative of a distance and angle from the laser scanner to the points on the surface. The surface may be an interior surface of the tubular and/or a surface of the cut in the wall of the tubular, e.g. a surface extending into the depth of the cut. The position of the points on the surface determined by the laser scanner may be indicative of the geometry of the cut in the wall of the tubular or other member. The measurement system may be configured to determine the geometry of the cut in the wall of the tubular or other member and/or of at least part of the wall of the tubular or other member surrounding the cut from the positions of the points on the surface, which may be determined at least in part using the laser scanner. The measurement system may be configured to determine the extent or progress, e.g. the depth, of the cut from the determined geometry of the cut in the wall of the tubular or other member and/or of at least part of the wall of the tubular or other member surrounding the cut from the positions of the points on the surface.
The tubular or other member may be hollow and/or elongate. The tubular or other member may comprise a casing, casing string or multiple string casing of well infrastructure, one or more cylindrical conduits, which may be at least partially nested within each other, and/or may comprise a pile, pipe, conductor and/or other onshore and offshore assets and infrastructure. The measurement system may be configured for insertion into the tubular or other member, e.g. for longitudinal translation along the inside of the tubular or other member. The measurement system may be configured to scan at least part of the tubular or other member from within the tubular or other member. Any suitable member may be used instead of the tubular.
The measurement system may comprise one or more, e.g. two or more, cameras or other electromagnetic radiation imaging apparatus or detectors, which may be arranged to collect stereoscopic images, e.g. for use in stereo photogrammetry.
The measurement system may comprise two more different types of measurement apparatus for determining an extent or progress of the cut, e.g. the laser scanner, the at least one visual imaging apparatus, such as stereo photogrammetry apparatus, electrical measurement apparatus, and/or the like. Although laser scanning, stereo-photogrammetry and electrical measurements are given as two beneficial examples of measurement apparatus, it will be appreciated that other suitable types of measurement apparatus could be additionally or alternatively used for determining the extent or progress of the cut. Having a diversity of measurement apparatus for determining the extent or progress of the cut may allow the extent or progress of the cut to be more accurately determined and/or determined in a wider range of environmental conditions or applications.
For example, the measurement system may comprise an electrical measurement system, such as an impedance based system, which may comprise a time domain reflectometery system. The electrical measurement system may comprise an electrical conductor that is deployable in a bore defined by the tubular. The electrical measurement system may comprise a signal generator configured to transmit a signal along the electrical conductor. The electrical measurement may comprise a signal receiver configured to receive a signal reflected in the electrical conductor from at least one boundary defined by the tubular. The electrical measurement may comprise a processor configured, in use, to use the received signal to determine the extent, progress and/or geometry of the cut through the tubular.
The tubular and the electrical conductor may define a waveguide for carrying the signal axially along the tubular and the electrical conductor. The boundary may be defined by a change in at least one electrical parameter along the electrical conductor. Optionally, the parameter may comprise an impedance value of the electrical conductor at the boundary. The processor may be configured to monitor the received signal to measure a change in the signal reflected by the boundary. Optionally, the processor may be configured to compare the transmitted signal with the received signal and determine whether any change in the received signal provides information relating to the progress of the cut. The processor may be configured to monitor the received signal by determining at least one of: a change in a time delay between transmission of the transmitted signal and receipt of the received signal; and a change in a time-variant signal amplitude or waveform of the received signal.
The signal generator and signal receiver may be provided between the tubular and the electrical conductor. Optionally, the signal generator and signal receiver may be positioned at surface and connected to the tubular and electrical conductor. Optionally, the signal generator and signal receiver may be connectable to the electrical conductor before introduction within the tubular and configured to be subsequently connectable to the tubular.
The electrical conductor may extend to a position relative to a portion of the tubular to be severed such that a portion of the electrical conductor extends beyond the boundary. The electrical conductor may be configured to: allow the signal to propagate along the electrical conductor beyond the boundary and be reflected along the electrical conductor, past the boundary again, and propagate to the signal receiver. The portion of the electrical conductor extending beyond the boundary may comprise a non-severed portion of the casing beyond the boundary. The electrical measurement system may comprise a clamping tool for electrically connecting to the non-severed portion of the casing. The electrical measurement system may comprise an impedance matching device to compensate for a difference between an impedance of the electrical measurement system and an impedance of the electrical conductor.
The cutting system may further comprise a rotating or movement head. The at least one cutting tool and/or the measurement system may be mounted on, coupled with or otherwise provided for motion or rotation with the rotating or movement head. In examples, the cutting system may comprise: the rotating head; the at least one cutting tool mounted on or coupled with the rotating head for rotation therewith; and the measurement system, which is mounted on, coupled with or otherwise arranged to rotate with the rotating head and/or the cutting tool.
The cutting system may be configured to cut, or form a cut in, the wall of the tubular. The cutting system may be configured to perform a full depth cut through the wall of the tubular from one side to the other. The cutting system may be configured to sever or separate one portion of the tubular from another, e.g. by cutting through the wall of the tubular. The measurement system may be configured to measure the extent, progress and/or geometry of the cut formed in the wall of the tubular by the cutting system.
The measurement system may be operable to follow the cutting tool, e.g. to rotate or move behind the cutting tool. The measurement system may be coupled with the cutting tool for movement or rotation therewith. For example, the cutting tool may be configured to be rotated or moved in a rotational or linear path by the rotating or movement head and the measurement system may be configured to follow the same rotational or linear path such that it reaches points on the rotational or linear path after the cutting tool. The cutting tool may be arranged such that it is rotated in a rotational plane around a rotational axis by the rotating head and the measurement system may be arranged to rotate in the same rotational plane as the cutting tool, but may follow behind the cutting tool. The measurement system may be in-line with the cutting tool. The measurement system may be located at the same distance longitudinally along the cutting system or rotational axis as the cutting system but may be arranged such that it is located circumferentially around the rotational axis relative to the cutting tool.
The measurement system may be configured for linear motion relative to a planar/flat surface, e.g. with a linearly moving head of a cutting system (i.e. the cutting system moving translationally rather than rotationally). For example, the cutting system may be arranged to form a longitudinal cut on a surface of a member which may comprise a cut through a planar/flat surface.
In this way, the measurement system may be arranged to measure down through the depth of any cut made by the cutting tool, such that measurement of the extent, depth profile or geometry of the cut may be improved.
The cutting system may be configured such that the measurement system rotates around the rotational axis or moves at substantially the same rotational speed or speed as the cutting tool, e.g. the measurement system may be coupled or connected to the cutting tool.
The cutting tool may be or comprise an abrasive cutting tool. The cutting tool may be or comprise a fluid jet cutting tool, such as a fluid abrasive jet cutting tool. The cutting tool may be configured to provide a pressurized jet comprising an abrasive material dispersed in water or another fluid. However, in other examples, it will be appreciated that other cutting tools could be used, such as saws, laser cutters, abrasive disc cutters, and/or the like.
The measurement system may be configured, operable or selectively operable to measure at least part of the cut (e.g. to measure the extent, progress and/or geometry of the cut) whilst the cutting tool is operating, e.g. operating to create the part of the cut being measured by the measurement system or another part of the cut. For example, the measurement system may be configured, operable or selectively operable to measure the extent or geometry of a part of the cut previously formed by the cutting system whilst the cutting system is cutting the wall of the tubular, e.g. to form a new part of the cut or to reprocess an existing part of the cut. In this way, the measurement of the extent or geometry of the cut may be performed in real time or in near real time, during cutting. This may provide an efficient measurement process, may minimise delays to the cutting process and/or may allow a faster decision as to whether or not to re-cut (e.g. if a cut is not full depth and/or completely through the wall of the tubular) to be made.
The measurement system may be operable or selectively operable independently of operation of the cutting tool. The measurement system may be configured, operable or selectively operable to measure the extent or geometry of at least part of the cut after and/or non-concurrently with the formation of at least part of the cut by the cutting tool, e.g. whilst the cutting tool is not operating or at least not being used to form a cut in the tubular. In this way, the amount of debris may be less, which may allow a better measurement of the extent or geometry of the cut. The cutting system may be selectively switchable between a mode in which the measurement system measures the extent of the cut whilst the cutting tool is operating to form the cut in the wall of the tubular and a mode in which the measurement system measures the extent of the cut whilst the cutting tool is not operating to form the cut. Accordingly, the scan performed by the measurement system may be conducted post-cut, i.e. the cut is formed by the cutting system and the measurement system operates once the cut has been formed (and the cutting operation may have been completed/finished) such that the cut is not being formed at the same time as the measuring system is operable.
The cutting system may be configured to provide a fluid flow or fluid jet into a volume adjacent the measurement system and/or measured by the measurement system. The fluid flow or fluid jet may comprise or be configured to provide a flow of water, such as clean water. For example, the cutting system may preferably comprise at least one fluid source or nozzle for providing the fluid flow or fluid jet into the volume adjacent the measurement system and/or proximate the portion of the cut and wall of the tubular being measured by the measurement system. The cutting system may be configured to selectively provide the fluid, e.g. clean water, from the cutting tool. The at least one fluid source or nozzle may be oriented to provide the fluid or jet of fluid directly into the volume measured by or adjacent the measurement system, e.g. at a portion of the cut being measured by the measurement system.
The cutting system comprises a shroud. The shroud is configured to extend at least part, or most or all of the way between the measurement system and the interior wall of the tubular, in use. The shroud may at least partly enclose and/or define an interior volume. The interior volume may be at least partially defined by the shroud and the interior surface of the wall of the tubular, in use. The measurement system may be configured to scan or measure the extent or geometry of a portion of the cut within the interior volume, in use. The measurement system may be configured to perform measurements inside the interior volume, in use. The at least one fluid source or nozzle may be configured to provide the fluid flow or fluid jet into the interior volume.
The shroud may extend between the cutting tool and the measurement system. The cutting tool may be provided outwith the interior volume and/or shroud.
The shroud is preferably movable with the measurement system and may rotate (with the measurement system), in the same rotational plane as the cutting tool. In addition, if the cutting system is arranged to perform a longitudinal cut in the member and the cutting system moves translationally (for example, over the flat/planar surface) then the shroud is also arranged to move translationally (e.g. in the longitudinal direction of the member which may be upwards and/or downwards).
In this way, the shroud may act to reduce the effect of debris from the cutting operation on the measurement of the extent or geometry of the cut performed by the measurement system. The above arrangement of fluid source or nozzle and shroud may synergistically work together to further enhance this effect.
The cutting system may comprise means for forming fluid flow, e.g. a vortex, in the interior of the tubular. For example, the at least one fluid source or nozzle (or at least one different fluid source or nozzle) and/or fins or other fluid guides may be arranged to provide the fluid flow or vortex in the tubular. The fluid flow or vortex may act to carry debris away from the measurement system, in use.
The cutting system may be configured for operation onshore or off-shore. The cutting system may be configured for operation on the surface or subsea. The cutting system may be configured for immersion in fluid, e.g. the cutting system may be water or fluid tight. The cutting system may be configured for operation down-hole, e.g. underground.
The system and/or method may be configured for use in retrieval operations for, but not exclusively, infrastructure abandonment operations such as well infrastructure abandonment operations, piling and other structural supports such as wind turbine piling, piling for moorings, platforms or buildings, or the like.
The cutting system and/or measurement system may comprise or be configured to communicate with a processing system, which may comprise a processor module, a data store and a communications system. The processor module may comprise one or more processors, which may be or comprise multi-core processors, and/or may comprise one or more central processing units and/or one or more graphical processing units, one or more maths coprocessors, one or more floating point units (FPUs), one or more field programmable gate arrays (FPGA's) or hybrid FPGA/processor device, one or more application specific integrated circuit (ASIC), and/or the like. The data store may be or comprise one or more hard disk, one or more solid state memories, and/or the like. The communications system may comprise a wired or wireless communications system. The processing system may comprise one or more user input devices, such as a keyboard, mouse, trackpad, touch screen, joystick, and/or the like. The processing system may comprise one or more user output devices, such as screens or touch screens, audio generators, haptic interfaces, and/or the like.
The processing system may be configured to provide a user interface, which may comprise a graphical user interface (GUI), an audio based smart assistant, and/or the like. The user interface may be configured to provide images, such as 2D or 3D model images, representative of the geometry of at least part of the interior surface of the wall of the tubular and/or the geometry and/or extent of the cut through the wall of the tubular, e.g. of the depth of the cut through the wall. The user interface may be configured to receive user input, e.g. control commands for controlling the cutting tool, the measurement tool and/or the at least one fluid source. The control commands may selectively activate or deactivate the cutting tool, the measurement tool and/or the at least one fluid source, change a mode of operation of the cutting tool, the measurement tool and/or the at least one fluid source, and/or the like.
The processing system may be configured to identify or distinguish between a partial depth cut and a full depth cut, e.g. from an interior to an exterior of the wall of the tubular, based at least partially on the measurements made by the measurement system, e.g. by using signature pattern recognition, intensity thresholding, AI or ML or other algorithms, modelling, prior use data or training sets, and/or the like. The processing system may be configured to automatically highlight the partial or full cut on the user interface, raise an alarm, alert or other notification, or the like, e.g. in real time or near real time.
The system may be configured to provide an indication that the section of tubular can be retrieved from the well if it is determined that the cut is a full depth cut around all or at least a threshold amount of its circumference. The system may be configured to stop a cutting operation if it is determined that the tubular is fully severed or continue with the cutting operation if it is determined that the tubular is not yet severed.
Described herein is a method for measuring and/or forming a cut in a tubular. The method may use the measurement system and/or the cutting system described above.
The method may comprise rotating or moving the cutting tool with the rotating or movement head. The method may comprise rotating or moving the measurement system with the rotating or movement head and/or the cutting tool. The method may comprise rotating or moving the measurement system behind the cutting tool. The method may comprise determining a geometry and/or extent of a cut through the tubular. The method may comprise determining an extent and/or geometry through a depth of the cut at least partially or wholly through a wall of the tubular, e.g. from one end of the cut to another.
The method may comprise collecting a 3D image or model of at least part of an interior surface of the wall of the tubular and/or any cuts in the wall of the tubular, e.g. down through the depth of the cuts. The method may comprise mapping the cut through the depth of the cut, e.g. from one end of the cut to another. The extent of the cut may be a depth of the cut from an interior surface of the wall of the tubular through the wall of the tubular. The method may comprise determining if the cut extends part of the way through the wall of the tubular or all of the way through the tubular. The 3D image or model may comprise a point cloud image.
The method may comprise inserting the measurement system and/or cutting system into the tubular, e.g. longitudinal translating the measurement system and/or cutting system along the inside of the tubular. The method may comprise measuring a geometry of at least part of the tubular from within the tubular. The method may comprise measuring a geometry of an interior surface of the wall of the tubular and/or through the depth of any cuts that extend from the interior surface of the wall of the tubular through or partially through the wall of the tubular. The method may comprise measuring through the geometry of the cut from an end of the cut at the interior surface of the wall of the tubular to a distal end of the cut, which may be within the wall of the tubular or on an exterior surface of the wall of the tubular.
The method may comprise cutting, or forming a cut in, the wall of the tubular. The method may comprise performing a full depth cut through the wall of the tubular from one side of the wall to the other. The method may comprise severing or separating one part of the tubular from another, e.g. by cutting through the wall of the tubular. The method may comprise scanning or measuring a portion of the wall of the tubular that has been cut by the cutting system. The method may comprise scanning or measuring the extent and/or geometry of the cut formed in the wall of the tubular by the cutting system.
The method may comprise rotating the measurement system so as to follow the cutting tool, e.g. to rotate the measurement system behind the cutting tool.
The method may comprise providing a fluid flow or fluid jet into a volume measured by the measurement system.
The method may comprise provide data representing images or models, such as 2D or 3D images or models, which may be representative of at least part of the interior surface of the wall of the tubular and/or the cut through the depth of the cut, e.g. based on the measurements provided by the measurement of the tubular. The method may comprise identifying or distinguishing between a partial depth cut and a full depth cut. The method may comprise automatically highlighting the partial or full cut on a user interface, raising an alarm, alert or other notification, or the like, e.g. in real time or near real time. The method may comprise stopping a cutting operation if the tubular is fully severed or continuing with the cutting operation if the tubular is not yet severed.
Described herein is a method of manufacturing, producing, assembling or repairing the measurement system and/or cutting system described above. The method may comprise providing a rotating head and coupling a measurement system to the rotating head for rotation therewith. The method may comprise coupling mounting or otherwise providing at least one cutting tool to the rotating head for rotation therewith. The method may comprise mounting the measurement system so that it rotates in substantially the same rotational plane as the cutting tool. The method may comprise mounting the measurement system so that it rotates behind the cutting tool. The method may comprise mounting a shroud to or around at least part of the measurement system. The method may comprise providing at least one fluid source or nozzle, e.g. in an interior volume at least partially enclosed by the shroud. Accordingly, the shroud may rotate (with the measurement system), for example in the same rotational plane as the cutting tool. In addition, if the cutting system is arranged to perform a longitudinal cut in the member and the cutting system moves translationally (for example over the flat/planar surface) then the shroud is also arranged to move translationally (e.g. in the longitudinal direction of the member which may be upwards and/or downwards).
The system and/or method may reduce the time taken to carry out retrieval operations; provide efficient retrieval operations; provide cost effective retrieval operations; provide reliable retrieval operations; and the like.
The system and/or method may provide information relating to a retrieval operation that may be used to determine progress of the retrieval operation. The information may be used to make a decision relating to the retrieval operation that may at least one of: reduce the time taken to carry out the retrieval operation; increase efficiency of the retrieval operation; decrease the cost of the retrieval operation; increase the reliability of the retrieval operation; and the like.
The system and/or method may be capable of indicating whether a cut is complete without physically attempting to pull tension on a tubular. The system may provide information that may determine whether or not it is appropriate to attempt to retrieve the tubular. The method, apparatus and/or tool may reduce the need to apply an 'over-pull' to the tubular, which may otherwise add significant time, complexity and/or additional equipment to a retrieval operation, for example, a well abandonment and/or decommissioning operation.
The system and/or method may reduce time spent cutting so that the cut may be verified without the need to pull on the tubular. The method, apparatus and/or tool may be used to reduce time spent cutting the tubular, which may result in decreased operating time and/or less rig or vessel time offshore (i.e. if the retrieval operation is being carried out offshore). The method, apparatus and/or tool may reduce the need to redeploy a cutting tool for example, following a failed cut. If the cutting tool needs to be redeployed to rectify a failed cut, it may be difficult and/or time-consuming to accurately re-position the cutting tool such that the cutting tool can continue cutting at the same cut location as previously. For multiple casing strings/tubulars, the method, apparatus and/or tool may verify that all of the casing strings/tubulars have been cut, which may save time and/or costs associated with carrying out multiple operations, for example, if a first cutting operation has been unsuccessful.
The cut may be carried out in optimal time (e.g. by stopping the cutting operation before cutting into a formation surrounding the tubular) rather than spending additional hours cutting (e.g. into the formation) to be certain that the tubular has been cut. This approach may reduce demand for consumables, maintenance and/or personnel on board (POB). The method may provide operational flexibility. For example, a large vessel or rig may be used on abandonment/decommissioning projects to provide the pulling force to verify that a well/casing/pile/pipe cut is complete. The system and/or method may allow an asset owner to mobilise a small vessel to carry out the retrieval operation (e.g. such that a vessel with lower pulling force capabilities may be used instead). In an example, an offline jacking system may be used to verify cut completion. Such a jacking system may take up a large proportion of deck area on a platform and may not be required if cut could be verified without resorting to an over-pull. The system and/or method may provide an operator with more options to carry out simultaneous operations if the rig or vessel operator can verify the cut 'offline' and use crane/derrick/other lifting services for other tasks.
The system and/or method described above or an alternative system and/or method may comprise using one or more electrical measurements to determine the extent or progress of the cut, which may comprise one or more of the steps or features outlined below.
The system and/or method may be used for determining progress of a cut through a tubular. The method may be part of a retrieval operation. The method may be part of an infrastructure abandonment operation such as a well infrastructure abandonment operation, or the like. The method may be part of a decommissioning operation. The method may comprise transmitting a signal along an electrical conductor. At least part of the measurement system and/or the cutting system (e.g. at least the cutting tool, rotating head and/or the measurement system) may be disposed in the tubular.
The system and/or method may comprise monitoring a received signal for a decrease of a signal-to-noise ratio or an increase of the signal-to-noise ratio. Upon cutting the tubular to form a severed portion of tubular, the boundary between the tubular and the severed portion of tubular may reduce electrical shielding of the tubular at the boundary such that the at least one electrical parameter of the electrical conductor may change at the boundary. The tubular may shield the electrical conductor from noise such that so far as the electrical conductor is within the tubular, any signal propagating along the electrical conductor may be at least partially shielded from noise. The technique may comprise using time domain reflectometry (TDR) to determine at least one of: a location of the boundary; and progress of the cut. The method may comprise predicting or modelling an impedance value along at least one of the tubular and electrical conductor. The method may comprise determining an appropriate waveform to use for the transmitted signal such that the received signal provides information on the boundary without being substantially affected by other discontinuities in at least one of: the tubular and electrical conductor.
The method may comprise distinguishing between a change in the received signal as a result of the cut and a change in the received signal caused by noise. The method may comprise using frequency domain analysis to distinguish between the change. The method may comprise grounding the tubular. The method may comprise applying a voltage between the tubular and electrical conductor to generate the signal for transmitting along the electrical conductor. The method may comprise electrically tying together a plurality of mutually insulated portions of the tubular, for example, multiple casing strings, or the like. The portions may be coaxial or may be non-coaxial. The method may comprise providing a signal generator between the tubular and electrical conductor. The method may comprise providing a signal receiver between the tubular and electrical conductor. The method may comprise using the signal generator to generate the signal for transmitting along electrical conductor. The method may comprise using the signal receiver to receive the signal reflected in the electrical conductor from the at least one boundary defined by the tubular. The method may comprise positioning the signal generator at surface and connecting the signal generator to the tubular and electrical conductor. The method may comprise positioning the signal receiver at surface and connecting the signal receiver to the tubular and electrical conductor. The method may comprise grounding the tubular and transmitting the signal along the electrical conductor. The method may comprise grounding the electrical conductor and transmitting the signal along the tubular. The method may comprise transmitting the signal along the electrical conductor in a first direction and receiving the signal in a second, opposite, direction. The first direction may be a downhole direction defined by the well infrastructure and the second direction may be an uphole direction defined by the well infrastructure. The method may comprise connecting the signal generator and/or signal receiver to the electrical conductor. The method may comprise introducing the signal generator and/or signal receiver within the tubular. The method may comprise connecting the signal generator and/or signal receiver to the tubular.
The method may comprise grounding the tubular and transmitting the signal along the electrical conductor. The method may comprise grounding the electrical conductor and transmitting the signal along the tubular. The method may comprise transmitting the signal along at least one of the tubular and electrical conductor in a first direction and receiving the signal in a second, opposite, direction. The first direction may be an uphole direction defined by the well infrastructure and the second direction may be a downhole direction defined by the well infrastructure. Connecting the signal to the tubular may comprise providing an electrical contact as part of a cutting tool for cutting the tubular and positioning the electrical contact relative to the tubular such that the signal generator is electrically connected to the tubular.
The electrical conductor may extend to a position relative to, for example the electrical conductor may be longer than, a portion of the tubular to be severed such that a portion of the electrical conductor extends beyond the boundary. The method may comprise transmitting along the electrical conductor such that the signal may at least one of: propagate along the electrical conductor beyond the boundary, be reflected along the electrical conductor, propagate past the boundary again, and may propagate to a signal receiver.
The method may comprise analysing the signal received from the electrical conductor to determine progress of the cut through the tubular. The method may comprise stopping a cutting operation if the tubular is fully severed or continuing with the cutting operation if the tubular is not yet severed.
If the tubular is fully severed, the method may comprise using a non-severed portion of the tubular beyond the boundary as part of the electrical conductor, wherein the cutting tool comprises a clamping tool for electrically connecting to the non-severed portion of the tubular. If the tubular is fully severed, the method may comprise indicating that a severed tubular can be retrieved. The method may comprise retrieving the severed tubular. If the cut is closed by the tubular moving, the method may comprise analysing the received signal to determine that a false indication of a failed cut has occurred. The method may comprise indicating that the tubular can be retrieved safely. The method may comprise determining if the cut is bridged by conductive material, such as metal swarf, other conductive debris, or water.
The electrical conductor may be provided on a string comprising a cutting tool for cutting the tubular.
The tool may comprise a cutting tool for cutting through a tubular, for example, as part of a cutting operation. The cutting tool may be for use in a retrieval operation. The cutting tool may be for use as part of an infrastructure abandonment operation such as a well infrastructure abandonment operation, or the like. The cutting tool may be for use as part of a decommissioning operation. The cutting tool may comprise a cutting tool for deploying to a location, for example, in the well infrastructure. The cutting tool may be configured for cutting the tubular at that location. The cutting tool may comprise an electrical conductor. The electrical conductor may be deployable together with the cutting tool in a bore defined by the tubular. The electrical conductor may be deployable together with the cutting tool in a bore defined by the tubular. The cutting tool may comprise a signal generator configured to transmit a signal along the electrical conductor. The cutting tool may comprise a signal receiver configured to receive a signal reflected from at least one boundary defined by the tubular. The cutting tool may comprise a signal receiver configured to receive a signal reflected in the electrical conductor from at least one boundary defined by the tubular. The cutting tool may comprise a processor configured, in use, to use the received signal to determine progress of the cut through the tubular. The tubular and the electrical conductor may define a waveguide for carrying the signal axially along the tubular and the electrical conductor. The boundary may be defined by a change in at least one electrical parameter along the electrical conductor. The parameter may comprise an impedance value of the electrical conductor at the boundary. The processor may be configured to monitor the received signal to measure a change in the signal reflected by the boundary. The processor may be configured to compare the transmitted signal with the received signal. The processor may be configured to determine whether any change in the received signal provides information relating to the progress of the cut. The processor may be configured to monitor the received signal by determining at least one of: a change in a time delay between transmission of the transmitted signal and receipt of the received signal; and a change in a time-variant signal amplitude or waveform of the received signal.
The signal generator and/or signal receiver may be provided between the tubular and the electrical conductor. The signal generator and/or signal receiver may be positioned at surface. The signal generator and/or signal receiver may be connected to the tubular and electrical conductor. The signal generator and/or signal receiver may be connectable to the electrical conductor before introduction within the tubular. The signal generator and/or signal receiver may be configured to be connectable, for example subsequently connectable, to the tubular. The electrical conductor may extend to a position relative to, for example the electrical conductor may be longer than, a portion of the tubular to be severed such that a portion of the electrical conductor may extend beyond the boundary. The electrical conductor may be configured to allow the signal to propagate along the electrical conductor beyond the boundary. The electrical conductor may be configured to allow the signal to be reflected along the electrical conductor, past the boundary again, and propagate to the signal receiver. The portion of the electrical conductor extending beyond the boundary may comprise a non-severed portion of the casing beyond the boundary. The cutting tool may comprise a clamping tool for electrically connecting to the non-severed portion of the casing. The cutting tool may comprise an impedance matching device to compensate for a difference between an impedance of the cutting tool and an impedance of the electrical conductor. The difference between the impedance of the cutting tool and the electrical conductor may result in at least one discontinuity that may cause at least one undesirable reflection of the signal(s) at the cutting tool location.
The apparatus may be used for determining progress of a cut through a tubular. The apparatus may be for use in a retrieval operation. The apparatus may be for use as part of an infrastructure abandonment operation such as a well infrastructure abandonment operation, or the like. The apparatus may be for use as part of a decommissioning operation. An electrical conductor may be provided in a bore. The bore may be defined by the tubular. The apparatus may comprise a signal generator for transmitting a signal along the electrical conductor. The apparatus may comprise a signal receiver for receiving a signal reflected in the electrical conductor from at least one boundary defined by the tubular. The apparatus may comprise a processor configured to use the received signal to determine progress of the cut through the tubular.
At least one feature of the method, apparatus and/or tool may replace any corresponding feature of any other method, apparatus and/or tool described herein. At least one feature of the method, apparatus and/or tool may be combined with any other method, apparatus and/or tool. Any reference to any feature of any method, apparatus and/or tool described herein may be provided in relation to any other method, apparatus and/or tool described herein. Any feature of any method described herein may be provided as part of, replace or be combined with any apparatus and/or tool described herein, and/or any feature of any apparatus described herein may be provided as part of, replace or be combined with any method and/or tool described herein, and/or any feature of any tool described herein may be provided as part of, replace or be combined with any method and/or apparatus described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

A description is now provided, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic illustration of a top view of an apparatus inside a tubular;
Figure 2 is a perspective view of a laser scanner of the apparatus of Figure 1 or Figure 2;
Figure 3 is a schematic illustration of a top view of an alternative apparatus inside a tubular;
Figure 4A is a schematic illustration showing a perspective view the apparatus of Figure 2, in use;
Figure 4B is a schematic illustration showing a rear-side perspective view the apparatus of Figure 2, in use;
Figure 5 is a schematic illustration of the apparatus of Figure 1 measuring a partial depth cut, in use;
Figure 6 is a schematic illustration of the apparatus of Figure 1 measuring a full depth cut, in use;
Figure 7 shows a camera image of a surface of a tubular, showing a partial depth cut, taking using the apparatus of Figure 1;
Figure 8 shows a front view of the surface and cut shown in Figure 7;
Figure 9 shows a top view of the surface and cut shown in Figure 7;
Figure 10 shows a camera image of a surface of a tubular, showing a full depth cut, taking using the apparatus of Figure 1;
Figure 11 shows a front view of the surface and cut shown in Figure 10;
Figure 12 shows a top view of the surface and cut shown in Figure 10;
Figure 13 shows a camera image of a surface of a tubular, showing a full depth cut with cement behind the cut, taking using the apparatus of Figure 1;
Figure 14 shows a front view of the surface and cut shown in Figure 13;
Figure 15 shows an isometric view of the surface and cut shown in Figure 13;
Figure 16 shows a top view of the surface and cut shown in Figure 13;
Figure 17 is a schematic illustration of a well and offshore platform in which the apparatus of
Figures 1 or 2 could be deployed;
Figure 18 is a schematic illustration of the apparatus of Figure 1 or Figure 2 in use; and
Figure 19 schematically depicts a method for determining progress of a cut through a casing of a well; and
Figure 20 is schematic illustration of another apparatus.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic illustration of a cutting system 5. The cutting system 5 comprises a cutting tool 10 attached to a rotating head 15. The rotating head 15 is configured to rotate around an axis of rotation 20 under the action of a motor, fluid drive or other suitable turning mechanism. The rotation of the rotating head 15 also rotates the cutting tool 10 around the axis of rotation 20. In use, the cutting system 10 is configured to be inserted into and moved along a hollow tubular 25. The axis of rotation 20 is generally parallel or coincident with a longitudinal axis of the tubular 25. The cutting tool 10 is oriented generally radially outwardly from the axis of rotation 20 so as to cut a wall 30 of the tubular 25 circumferentially as it is rotated around the axis of rotation 20 by the rotating head 15. In the present example, the cutting tool 10 is an abrasive water cutter that is configured to emit a pressurised jet of fluid, wherein the fluid comprises an abrasive material dispersed in water. The pressurised jet of water acts to abrade through the wall 30 of the tubular 25 so as to form a cut 35 into the wall 30. However, in other examples, a different cutting tool such as a saw, laser, abrasion disk or the like may be used.
Beneficially, such apparatus can be used to remove sections of the tubular 25, e.g. during a decommissioning operation. In this case, it is intended that the cut 35 extends fully through the depth of the wall 30 of the tubular 25 from a radially inner surface to a radially outer surface thereof and around the entire circumference of the tubular 25 such that the cut 35 effectively severs and separates one section of the tubular 25 from another.
However, regardless of the cutting tool 10 that is used, there is a risk that the cut 35 will fail to adequately sever the section of tubular 25. That is, at least part of the cut 35 is not full depth through the wall 30 of the tubular 25. In this case, the failure in the cut 35 may not be identified until after the cutting system 5 has been moved or withdrawn from the tubular or even until a crane or other lifting equipment is used to try to move the section of tubular 25. This can be inefficient, time consuming and result in unnecessary cost.
The cutting system 5 of Figure 1 further comprises a measurement system 40 for measuring an extent of the cut 35 in the wall 30 of the tubular 25, particularly the depth of the cut 35 through the wall 30 of the tubular 25 so as to determine whether the cut is full depth through the wall 30 of the tubular 25 (i.e. from the radially interior surface to the radially outer surface thereof) or not.
In this example, the measurement system 40 comprises a laser scanner 45. The laser scanner is mounted to the rotating head 15 for rotation therewith around the rotation axis 20. The measurement system 40 is arranged in the same rotational plane as the cutting tool 10. However, the measurement system 40 is configured to follow the cutting tool 10. As such, although the measurement system 40 is provided in the rotational plane of the cutting tool 10, it is provided circumferentially around the axis of rotation 20 with respect to the cutting tool 10 such that it follows behind the cutting tool 10 whilst the rotating head 15 and thereby the cutting tool 10 and measurement system 40 are being rotated. In this way, the measurement system 40 is configured to scan part of the wall 30 of the tubular 25 after the cutting tool 10 has passed / cut it. Advantageously, as the measurement system 40 follows behind the cutting tool 10 in the same rotational plane, e.g. being provided adjacent the cutting tool 10, then it may be easier to align the measurement system 40 with the cut 35 in the wall 30 of the tubular 25 formed by the cutting tool 10. This may, in turn, improve the line of sight of the measurement system 40 into the depth of the cut 35, which may improve the accuracy of the depth measurement of the extent of the cut 35 and the associated determination of whether the cut 35 is full depth or not.
As shown in more detail in Figure 2 and 4A, the laser scanner 45 comprises a laser 50 for emitting a laser beam (not shown) and a receiver 55 for receiving a reflection of the laser beam from a surface (in this case of the wall 30 of the tubular 25, in use). The laser scanner 45 is optionally configured to sweep the laser beam in one direction (e.g. perpendicularly to the plane of rotation of the measurement system 40) or in two directions (e.g. perpendicularly to and in the plane of rotation of the measurement system 40). At least part, such as the centre, of the sweep pattern of the laser beam is aligned with (e.g. is provided adjacent, or circumferentially or in the rotational plane of) a cutting part (e.g. the abrasive water jet) of the cutting tool 10. The receiver 55 receives any reflection or backscatter of the laser beam and the laser scanner is configured to use techniques such as, but not limited to, time of flight and Doppler shift to determine a 3D model, generally in the form of a 3D point cloud map, of the surface being imaged, in this case the interior surface of the wall 30 of the tubular 25 and the depth profile through any cut 35 in the wall 30. Laser scanners per se are known in the art and so discussion of possible components of the laser scanner 45 is kept brief.
As shown in more detail in Figures 5 and 6, the measurement system 40 may comprise one or two or more digital cameras 60 (e.g. CMOS or CCD based cameras) for imaging the wall 30 of the tubular 25 and inside any cut 35 therein. Optionally, one or more, e.g. at least a pair of cameras 60 can be provided, which are arranged spaced apart so as to perform stereo photogrammetry, which can be used in addition to the laser scanner 45 to supplement the 3D model of the cut 35. The stereo photogrammetry may be used as an alternative to the laser scanner 45. However, the laser scanner 45 may provide beneficially accurate and/or high resolution depth imaging of the cut 35. Stereo photogrammetry and/or other cut measurement techniques, e.g. electrical measurement techniques such as time domain reflectometry and electrical impedance based techniques may be beneficial in certain situations, e.g. in certain debris filled environments. As such, the combination of two or more measurement techniques may prove to be beneficial in maintaining performance of the measurement system over a wider range of operational environments.
The measurement system 40 is optionally provided with a clean fluid outlet 65, in this example in the form of a water jet nozzle. The clean fluid outlet 65 is configured to provide a stream of clean fluid 70 into a volume around the part of the wall 30 of the tubular 25 being measured by the measurement system 40. Debris 75 created by the cutting process and dislodged from the surface of old tubulars may interfere with the scanning process and particularly with the laser beam and the line of sight of the cameras of the measurement system 40. The stream of clean fluid 70 provided by the clean fluid outlet may serve to displace at least some of the debris 75 from the area around the measurement system 40, thereby mitigating against interference due to the debris 75.
In addition, a shroud 80 is optionally provided that extends between the measurement system and the wall 30 of the tubular 25 or a position proximate thereto. In particular, the shroud 80 partly encloses an area between the laser scanner 45, cameras 60 and other measurement components of the measurement system 40 and the wall 30 of the tubular 25 such that a loosely enclosed volume 85 is defined by the shroud 80, the measurement system 40 and the wall 30 of the tubular 25, in use. The provision of the shroud 80 may help prevent debris 75 from entering the volume adjacent the measurement system 40, thereby mitigating against interference due to the debris 75. Optionally, the enclosed volume 85 isn't water tight and the clean fluid outlet 65 provides the stream of clean fluid 70 into the enclosed volume. This displaces the dirty water and debris 75 from the volume 85 and localises the clean fluid 70 in the vicinity of the measurement system 40, such that the combination of the shroud 80 and the clean fluid outlet 65 further mitigates against interference due to the debris 75 and dirty water.
An alternative arrangement of the cutting system 5 of Figure 1 is shown in Figures 3, 4A and 4B. The cutting system 105 of Figures 2, 4A and 4B is similar to the cutting system 5 of Figure 1 and like components are provided with like reference numerals but incremented by 100. In the measurement system 105 of Figures 2, 4A and 4B, the measurement system 140 is mounted directly to a side of the cutting tool 110, wherein the cutting tool 110 is directly mounted to the rotating head 115 and the measurement system 140 is indirectly mounted to the rotating head 115 via the cutting tool 110. In this way, the measurement system 140 follows behind the cutting tool 110 when the rotating head 115 is being rotated. This arrangement may make it easier for the measurement system 140, particularly the laser 150 and receiver 155 to be aligned with any cut 135 made by the cutting system 105.
The operation of the cutting system 5, 105 to determine whether or not the cut 35, 135 in the wall of the tubular 25, 125 is full depth or only partial depth is illustrated with reference to Figures 5 to 16. Figure 5 shows the measurement system 40, 140 being used to measure the geometry of a partial depth cut 35, 135 in the wall 30, 130 of the tubular 25, 125. An image of the cut 30, 130 taken by the camera 60 is shown in Figure 7. From this, it can be seen that the partial depth 30, 130 cut can be difficult to clearly make out from photographic images alone.
As can be seen from Figure 5, the laser beam of the laser scanner 45, 145 is scanned onto the interior surface of the wall 30, 130 of the tubular 25, 125 immediately surrounding the cut 35, 135 and also on a back wall 90 of the deepest point of the cut 35, 135 formed within the wall 30, 130 of the tubular 25, 125. Some laser light will also be incident on the side walls 95 of the cut 30, 130. However, the light reflected from the side walls 95 of the cut 30, 130 will be highly scattered such that less light will be detected from the side surfaces 95.
As a result, as shown in Figure 8, a front view of the 3D model constructed from the laser scan data collected by the laser scanner 45, 145 shows distinctive parallel dark lines corresponding to the sides 90 of the cut 30, 130 on either side of a bright line representing the back wall 90 of the cut 30, 130, from which more of the laser light is scattered relative to the side walls 95. In this way, the presence of a partial depth cut 30, 130 gives rise to an associated signature pattern in the laser scan data, which may provide for easy recognition.
The partial depth nature of the cut 30, 130 is also easy discernible in the top view representation shown in Figure 9 and derived from the 3D model formed using the laser scan data collected by the laser scanner 45, 145. In this case, a bright line can be seen corresponding to the inner surface of the wall 30, 130 of the tubular 25, 125 and a second bright line representing the back wall 90 of the cut 35, 135 can be seen behind the bright line representing the wall 30, 130 for those parts of the cut 35, 135 that are partial depth. From this top view, it is straightforward to measure the depth of the cut 35, 135, which is proportional to the distance between the two bright lines. This information can be useful when deciding on future operations. In this case, the depth of the cut can be measured as 10mm.
Figure 6 shows the laser beam of the laser scanner 45, 145 incident on the interior surface of the wall 30, 130 of the tubular 25, 125 immediately surrounding a full depth cut 35, 135 that passes through the wall 30, 130 of the tubular 25, 125 from one side to the other, i.e. from an interior side to an exterior side. In this example, no structure is provided on the exterior side of the tubular 25, 125. In this case, an appreciable amount of laser light is reflected from the interior surface of the wall 30, 130 of the tubular 25, 125 but very little of the laser light is reflected from the cut 35, 135 and most of the laser light incident on the cut simply passes through the cut and is not reflected back to the receiver 55. Figure 10 shows a camera image of the front of the cut 35, 135 and surrounding areas of the interior surface of the wall 30, 130 of the tubular 25, 125. The full depth cut 30, 130 is clearly seen as a single black band in the front view from the 3D model shown in Figure 11 that is constructed using the laser scanning data from the laser scanner 45, 145. Similarly, the full depth cut 30 can be seen in the top view image of the 3D model shown in Figure 12 that is constructed using the laser scanning data from the laser scanner 45, 145. In this case, the interior surface of the wall 30, 130 of the tubular 25, 125 is clearly seen as a single bright line and, in contrast to the partial depth cut 30, 135 shown in Figure 9, no secondary line is seen behind as there is no back wall 90 of the cut 30, 130 to reflect from. This may be a signature pattern indicative of a full depth cut. Of note, in both Figure 11 and Figure 12, some grooves or other structure in the cut that reflect light can be seen and quantified.
In real applications, the possible situations are not limited to those shown in Figures 5 to 12. For example, Figures 13 and 16 show images taken by the measurement system 40, 140 of a full depth cut 30, 130 through the wall of a tubular 25, 125, wherein cement 97 or other structure is provided around the exterior of the tubular 25, 125. In this case, in a camera image shown in Figure 13 taken by the camera 60 and the front view of the 3D model constructed using the laser scanning data from the laser scanner 45, 145, the cut 30, 130 superficially looks like those of the partial depth cut shown in Figures 7 and 8 respectively. An isometric view of the cut 30, 135 with the cement 97 at the exterior side thereof that has been created using the 3D model constructed using the laser scanning data from the laser scanner 45, 145 is shown in Figure 15. In this case, the interior surface of the wall 30, 130 of the tubular 25, 125 and the cement 97 at the back of the cut 30, 130 are clearly highlighted by bright areas of the image and the cut 30, 130 itself is shown as a dark space therebetween. However, in a top view constructed using the laser scanning data from the laser scanner 45, 145, as shown in Figure 16, the distance between the interior surface of the wall 30, 130 of the tubular 25, 125 represented by one of the bright lines and the cement 97 represented by the second bright line can be readily determined and compared with the thickness of the wall 30, 130 of the tubular 25, 125 (which may, for example, be stored in a database or look-up table). In this case, if the determined distance is the same or greater than the thickness of the wall 30, 130 of the tubular 25, 125, then the cut 35, 135 is likely a full depth cut whereas if the determined distance is the less than the thickness of the wall 30, 130 of the tubular 25, 125, then the cut 35, 135 is likely a partial depth cut. This check may be performed automatically or by an operator to check if a detection of a partial depth cut is instead a full depth cut with some backing structure such as the cement 97 or rock formation or the like being present around the outside of the tubular 25, 125.
In this way, by using the laser scanner 45, 145 it is possible to distinguish between full depth and partial depth cuts 30, 130 under a wide range of possible circumstances. Furthermore, not only can the measurement system 40, 140 distinguish between full and partial depth cuts, the system is capable of characterising the cut 30, 130, e.g. determining the depth of any partial depth cut 30, 130, distinguishing between partial depth cuts and full depth cuts 30, 130 with external structure such as cement 97 and identifying grooves, notches and the other joining structures in cuts 30, 130 and the extent thereof. This may further assist in assessing whether or not to cut again using the cutting tool 10, 110 or if the cut 30, 130 is sufficient to allow the section of the tubular 25, 125 to be separated using pulling equipment.
The 3D models constructed using the laser scanning data from the laser scanner 45, 145 and the images collected by the camera 60 may be presented to an operator to allow them to characterise any cut and to decide on a suitable processing action. Additionally, the system may comprise a processing system for automatically classifying cuts, e.g. using signature pattern matching, artificial intelligence, machine learning or other algorithms or by comparison with modelled, training or prior data, and to highlight, issue a notification, alert or alarm when any partial depth cuts or other undesirable situation are identified. For example, the system may be configured to issue a notification that the section of tubular 25, 125 is ready for lifting if the cut is determined to be full depth around all or at least a threshold amount of the circumference of the tubular 25, 125.
Figure 17 illustrates well infrastructure, which in this example is in the form of a well 210 having a tubular 25, 125 in the form of casing 212 extending below a seabed 214 into a formation 216. In this example, a wellhead 218 of the well 210 is located on a well deck 220 of an offshore platform 222 connected to the casing 212 via a pipe structure 224, which may be conductor, riser or the like. In a cutting operation, the cutting system 5, 105 is introduced into the well 210 via a bore 228 of the casing 212. Upon reaching a cut location 230 within the casing 212, which may for example be 15-30 metres below the seabed 214, the cutting tool 10, 110 of the cutting system 5, 105 is activated. In a cutting operation, the cutting tool 10, 110 performs a radial cut (e.g. by using water jet abrasive cutting technology, or the like) and rotates to circumferentially cut the casing 212 (for example, by rotating the cutting tool 10, 110 or rotating a cutting element of the cutting tool 10, 110 a number of times until the casing 212 has been completely severed). The cutting operation may be a time-consuming operation. For example, the cutting tool 10, 110 (or a cutting element of the cutting tool 10, 110) may need to be rotated a minimum number of times (e.g. one or more 360° rotations) in order to completely sever the casing 212. To avoid the need to re-deploy the cutting tool 10, 110 for a second cutting operation, it may be desirable to continue cutting with the cutting tool 10, 110 (e.g. which may result in cutting into the formation 216 surrounding the casing 212) to ensure that the casing 212 is completely severed. However, such an approach may waste time and have a cost implication.
Reference is now made to Figure 18, which illustrates an example of an apparatus 240 for determining progress of a cut 30, 130 through the casing 212. In this example, the casing 212 includes multiple casing strings 212a-212b (e.g. two or more casing strings) at the cut location 230. Typically, all of these strings 212a-212b need be severed (e.g. a complete multi-string cut) during the cutting operation. It may however be difficult to determine if or when each casing string 212a-212b has been completed severed.
In one example, the apparatus 240 may be the cutting system 5, 105 described above in relation to Figures 1 to 17. However, in another example, in addition to the measurement system 40, 140, the apparatus 240 may comprise additional means for determining if the cut 30, 130 is full depth or partial depth. An example of an additional or alternative mechanism for determining if the cut 30, 130 is full depth or partial depth using electrical measurements is described below.
In an example, the casing strings 212a-212b may be mutually insulated from each other such that the casing strings 212a-212b are not provided in electrical communication with each other. In another example, the casing strings 212a-212b may be electrically tied together, for example, to ensure that each casing string 212a-212b is held at a common potential.
The casing 212 defines an electrical conductor, which in this example takes the form of the steel tubular 25, 125. The cutting tool 10, 110 is in communication with and operated from the offshore platform 222 via a cutting tool string 244 (shown in Figure 1). In this example, the cutting tool string 244 comprises an electrical conductor 246. The electrical conductor 246 provides electrical communication between surface and the cutting tool 10, 110. The cutting tool 10, 110, for example a body, component or surface of the cutting tool 10, 110, forms part of the electrical conductor 246 such that any signal that propagates along the electrical conductor 246 also propagates along the cutting tool 10, 110. The cutting tool string 244 may include a separate electrical conductor such as a metal wire, e-line, or the like that is provided as part of, externally carried by or integral with the cutting tool string 244. In another example, the cutting tool string 10, 110 itself may define the electrical conductor 246, for example, by allowing a signal to be propagated along a body of the cutting tool string 244. In an example, the cutting tool 10, 110 may not form part of the electrical conductor 246 (e.g. the cutting tool 10, 110 may be electrically isolated from the electrical conductor 246), but may instead carry or support the electrical conductor 246. For example, the cutting tool 10, 110 may be configured to allow the electrical conductor 246, which may be in the form of a wire, e-line, or the like, to extend at least partially through/along the cutting tool 10, 110. If the cutting tool 10, 110 forms part of the electrical conductor 246, the electrical conductor 246 may be terminated at the cutting tool 10, 110, for example, at a lower end 247 of the cutting tool 10, 110 that is provided in electrical communication with the electrical conductor 246. If the cutting tool 10, 110 is electrically isolated from the electrical conductor 246, the electrical conductor 246 may be terminated at an end of the electrical conductor 246 itself. The end of the electrical conductor 246 may be provided within or on the cutting tool 10, 110, or may extend below/beyond the cutting tool 10, 110.
The electrical conductor 246 is provided (e.g. deployed) within the bore 228 of the casing 212 (e.g. within an inner casing). Deploying the electrical conductor 246 within the bore 228 of the casing 212 may be relatively straightforward since the electrical conductor 246 may be provided as an integral component or beside the cutting tool string 44 as the cutting tool 226 is introduced into the casing 212.
The apparatus 240 includes a signal generator 248 for applying a signal to the electrical conductor 246 (e.g. to cause a signal or "transmitted signal" to be transmitted along the electrical conductor 246). The apparatus 240 further includes a signal receiver 250 for receiving a signal (e.g. a "received signal", which may include at least one reflected signal and/or at least one re-reflected signal) from the electrical conductor 246. The apparatus 240 further includes a processor 252 configured to use the received signal to determine progress of the cut through the casing 212. In this example, the processor 252 is connected to a time domain reflectometry (TDR) device 254 that includes the signal generator 248 and the signal receiver 250 connected to the electrical conductor 246 and configured to respectively send and receive signals from the electrical conductor 246. The TDR device 254 is provided in electrical communication with the electrical conductor 246, which may comprise a wire, cable, or the like, extending from the TDR device 254. The TDR device 254 is also provided in electrical communication with the casing 212 via an electrical contact 242. TDR may be used to detect discontinuities on a constant impedance transmission line or waveguide, for example, by measuring characteristics of the signal reflected by the change in impedance at the discontinuity. The processor 252 is connected to (or provided as part of) a PC 282, which may be used to display information relating to the progress of the cut, control any process, control the TDR device 254 and/or provide instructions/information relating to the cutting operation, or the like.
Before, during or after the cutting operation, a signal generated by the signal generator 248 is transmitted along, for example axially along, the electrical conductor 246. The electrical conductor 246 and casing 212 may define a waveguide 258 of the apparatus 240. The casing 212 may be held at a constant potential, for example, while a potential applied to the conductor 246 is varied to inject a signal that propagates along the electrical conductor 246/waveguide 258. The signal may propagate along the electrical conductor 246 until the signal encounters a change in an electrical parameter (e.g. impedance, or the like) of the waveguide 258. The signal may then be reflected at the change such that a reflected signal propagates along the waveguide 258. The electrical conductor 246 may provide a reliable signal path for propagating the signal(s) along the waveguide 258. For example, the electrical conductor 246 and/or cutting tool 226 may be constructed to ensure that there is constant impedance, well-known impedance or controlled impedance along the length of the electrical conductor 246, which may help to prevent spurious reflected signals propagating in the waveguide 258. Providing the electrical conductor 246 with known characteristics such as constant impedance, or the like, may allow the signal(s) to propagate in the waveguide 258 with minimal disruption and/or optimum reliability rather than having to rely on another electrical conductor with unknown or difficult to ascertain characteristics, for example, part of the casing 212.
As the cutting tool 226 severs the casing 212, the impedance and/or another electrical parameter of the waveguide 258 may change at the cut location 230. The change of the impedance of the waveguide 258 at the cut location 230 may define a boundary or discontinuity of the waveguide 258 that reflects and/or absorbs the signal. For example, the boundary may be defined by the casing 212 at the cut location 230 that causes a change in the characteristic impedance of the waveguide 258 such that a signal is reflected in the electrical conductor 246 by the change in the characteristic impedance (and thus, the reflected signal may indicate the location and/or progress of the cut). By comparing the transmitted signal with the received signal at the TDR device 254, it may be possible to determine the cut location 230 (e.g. via a time delay between the transmitted and received signals) and/or the progress of the cut through the casing 212 (e.g. by analysing the received signal to determine whether the casing 212 has been partially or completely severed).
In an example, a pulsed or time-variant waveform electrical potential is applied between the casing 212 and the electrical conductor 246 by the signal generator 248 to generate the signal for transmission along the waveguide 258 (e.g. in a downhole direction 259 defined by the well 210). The electrical conductor 246 may be located close to the centre of the bore 228, and electrically isolated from the casing 212. TDR may produce an electromagnetic wave resulting from the applied potential that travels along the waveguide 258, and is reflected (e.g. in an uphole direction 261 defined by the well 210) at any changes in characteristic impedance. In this sense, the apparatus 240 may be analogous to a coaxial cable with the casing 212 representing a shield and the conductor 246 representing a core of the coaxial cable. Cutting the shield of a coaxial cable may result in a change in impedance of the core at the location of the cut such that a signal is reflected at this point. By using information present in any reflected or re-reflected signal in the apparatus 240, it may be possible to determine the progress of the cut through the casing 212. It will however be appreciated that the apparatus 240 may not be considered to be an ideal coax. For example, the conductor 246 may not be concentric with the casing 212 along the bore 228 and/or the bore 228 may be filled with sea water and other contaminants, which may cause a change in the impedance of the electrical conductor 246. As the cutting tool 226 progresses with the cut, the thickness of the casing 212 at the cut location 230 decreases such that the radial separation between the electrical conductor 246 and the casing 212 increases. The change in the geometry of the casing 212 and electrical conductor 246 at the cut location 230 causes a change in the characteristic impedance of the waveguide 258 at the cut location 230. By analysing the reflected signal(s) it may be possible to determine the progress of the cut as the impedance at the cut location 230 changes.
Initial testing of the apparatus 240 indicates that there may be at least one change to impedance as the cut progresses. Once the casing 212 has been severed, the waveguide 258 forms an 'open circuit' at the cut location 230, which causes a measurable change in the received signal.
In a typical TDR implementation, the conductors are typically designed as transmission lines, to maintain a constant characteristic impedance along their length. Such a design provides the ability to carry high speed signals, and the like. In the context of the well 210, the casings 212 being severed are unlikely to have such constraints, and may have several features that may result in the characteristic impedance being inconsistent along the length of the waveguide 258.
Reference is now made to Figure 19, which illustrates an example of a method 260 of determining progress of a cut through the casing 212 of the well 210. In the given example the method uses electrical measurements to determine the extent or progress of the cut, but in other examples, the use of the laser scanner 45, 145, stereo photogrammetry and other techniques described above can be used to determine an extent or progress of the cut instead of or in addition to the electrical method described. The method 260 includes a step 262 of transmitting a signal (e.g. using the signal generator 248) along the electrical conductor 246. The method 260 further includes a step 264 of using a signal received (e.g. using the signal receiver 250) from the electrical conductor 246 to determine progress of the cut through the casing 212.
The method 260 includes a step 266 of monitoring, for example continually monitoring, the received signal to measure a change in the signal reflected by the boundary. The step 266 may include a step 268 of comparing the transmitted signal with the received signal and determining whether any change in the received signal provides information relating to the progress of the cut. The received signal may be analysed in a step 268 to determine whether to allow the cutting operation to continue 270 if the casing 212 is not yet severed or to stop 272 the cutting operation if the casing 212 has been fully severed (or if a problem is encountered). If the casing 212 has been fully severed then the method 260 may indicate 274 that the casing 212 can be retrieved from the well 210.
The step 266 of monitoring the received signal may determine at least one of: a change in a time delay between transmission of the transmitted signal and receipt of the received signal; and a change in a pulse shape or time-variant waveform of the received signal.
Alternatively or additionally, the step 266 may monitor the received signal for a decrease of a signal-to-noise ratio or an increase of the signal-to-noise ratio. For example, a change in the signal-to-noise ratio may occur upon cutting the casing 212. The cutting or severing of the casing 212 may reduce electrical shielding of the casing 212 at and/or downhole of the boundary. For example, the casing 212 may shield the electrical conductor 246 from noise such that so far as the electrical conductor 246 is within the casing 212, any signal propagating along the electrical conductor 46 is at least partially shielded from noise.
In a cutting operation, the cutting tool 226 may not be in a central position within the casing string 212a. As a result, it may not be possible to calculate the characteristic impedance of the waveguide 258 in advance. The TDR device 254 may need to have its impedance accurately matched to the characteristic impedance of the casing 212 at a signal injection point 263 of the signal being transmitted into the casing 212 to minimise reflection at the signal injection point 263. If necessary, variable impedance and a measurement, calibration, and/or matching process may be used to minimise reflection at the signal injection point
The casing 12 may not have a consistent impedance along its length, for example, due to presence of sea water and other contaminants which vary along the length. The sea water and other contaminants may act to vary the permittivity and/or permeability between the conductive paths defined by the casing 212. The casing 212 may also include various joints and other inconsistencies of material dimensions and properties that vary permittivity and/or permeability of the conductive paths.
The variations in permittivity and/or permeability along the waveguide 258 may in turn vary the characteristic impedance along the waveguide 258. Reflections from each variation may increase the noise level of the received signal. For example, reflections may then travel along the conductive paths and re-reflect at subsequent discontinuities in characteristic impedance. Time-gating may not be sufficient to ignore the resulting reflections as the re-reflections may arrive at the same or similar time as the reflections from the cut location 230.
If this needs to be addressed, the TDR device 254 may be configured to transmit a robust signal (such as a predetermined or pre-calculated waveform) which provides good detectability in the presence of multiple reflections rather than a simple pulse or time-variant waveform of standard TDR implementations. For example, it may be possible to predict or model an impedance value along the waveguide 258, and determine an appropriate waveform to use for the transmitted signal such that the received signal provides information on the boundary without being substantially affected by other discontinuities in the waveguide 258. Other measures such as frequency domain analysis may be used to distinguish between a change in the received signal as a result of the cut and a change in the received signal caused by noise.
If the cut is closed by the casing 212 moving downwards, the received signal may falsely indicate a failed cut. The failed cut may be registered because the casing 212 (i.e. the severed portion of the casing 212) may move downwards into electrical contact with the non-severed portion 213 of the casing 212, which may result in a zero, negligible or only small change in the characteristic impedance at the cut location 230. If the cut is closed by the casing 212 moving, it may be possible to analyse the received signal (e.g. as part of step 268) to determine that a false indication of a failed cut has occurred. If the casing 212 has been completely severed, the step 268 may indicate that the casing 212 can be retrieved safely from the well 210.
The step 268 may include determining if the cut is bridged by conductive material, such as metal swarf, other conductive debris, water, or the like. If the cut is indeed bridged by conductive material, the expected open circuit that may occur when the cut is complete may not be clear. If this needs to be addressed, it may be possible to analyse (e.g. using frequency domain analysis, or the like) to differentiate between conductive debris and an uncut metallic 'tang' or remaining metallic/electrical connection between the severed portion of casing 212 and the non-severed portion 213 of the casing 212, in which case it may be necessary to continue the cutting operation.
In ideal circumstances, the cut may result in a visibly clear indication of a cut being completed which can either be learned by the operator of the apparatus 240 or via a computer program. However, it is possible that there will be artefacts from the various issues noted above which make the waveform display insufficient for accurately determining whether the cut has been completed or not.
If this needs to be addressed, additional analysis providing a different presentation of the data (e.g. a spectrogram plot, or the like) or analysis of the data (e.g. in the form of machine learning, extracting differences from a reference signal, or the like) may be required to aid the operator.
In an example, the cutting tool 226 extends a distance below (e.g. downhole of) the cut location 230. In an example, it may be difficult to detect the new discontinuity at the cut location 230 when the discontinuity at the end of the conductive path defined by the cutting tool 226 is close to the cut location 230. If the cutting tool 226 defines part of the electrical conductor 246 (or the electrical conductor 246 is electrically isolated from the cutting tool 226 and extends below the cut location 230), any signal reflected by an electrical termination of the cutting tool 226 (or by an electrical termination defined by the electrical conductor 246) may pass the discontinuity at the cut location 230, which may cause a change in the reflected signal that may be detectable using the TDR device 254.
A portion of the electrical conductor 246 (whether electrically isolated from the cutting tool 226 or electrically in communication with the cutting tool, or the like) may extend a distance (e.g. more than 0.1 m, more than 0.3m, less than 0.5 m, less than 1m, less than 2 m, less than 3 m, less than 5 m, less than 10 m, greater than 10 m, or the like) below the cut location 230. The electrical conductor 246 may effectively extend below the cut location 230 so that any signal propagating along the waveguide 258 experiences the impedance change at the cut location 230 to form a reflected or re-reflected signal.
In another example, the electrical conductor 246 may be additionally or alternatively extended by using a non-severed portion 213 of the casing 212 (e.g. below the cut location 230) as an extension of the electrical conductor 246. In this example, a clamping tool 227 is used to electrically connect the cutting tool 226 to the non-severed portion 213. In an example, the clamping tool 227 may only be electrically connected to the non-severed portion 213 once the cut has been completed to avoid a short-circuit situation. The non-severed portion 230 may effectively extend for e.g. several kilometres down to the bottom of the well 210, depending on the length of the well 210. The clamping tool 227 may be configured to be electrically connecting to the casing 212 by providing an electrical contact between cutting tool 26 and the non-severed portion of casing 213.
Alternatively or additionally, an impedance matching device 265 (e.g. in the form of circuitry within the cutting tool 226, at surface, or the like) may be provided for compensating for any change in the impedance of the cutting tool 226. For example, due to geometrical considerations (e.g. the dimensions and/or positioning of the cutting tool 226 relative to the casing 212, or the like), the impedance of the waveguide 258 at the cutting tool 226 may vary compared with the impedance elsewhere along the waveguide 258. Providing the impedance matching device 265 may compensate for any change in the characteristic impedance that may otherwise cause further reflections to be produced in the waveguide 258 which could mask the reflection caused by the change in the impedance at the cut location 230. The impedance matching device 265 may include a termination matched to the characteristic impedance of the TDR device 254 (and/or any other circuitry of the waveguide 256 affecting the impedance). The impedance matching device 265 may help to provide a clearer indication of the cut location/progress, by preventing or reducing reflections compared with a cutting tool 226 that has not been impedance-matched.
Reference is now made to Figure 20, in which an alternative configuration of the apparatus 240 illustrated by Figure 18 is now described. Figure 20 illustrates an apparatus 340 including features that may be like or similar to corresponding features of the apparatus 240 illustrated by Figure 18. Like or similar features are indicated by reference numerals incremented by 100 compared to the corresponding features in Figure 18.
The apparatus 340 includes a cutting tool 326 that is configured to be electrically connected to the casing 32 so that the signal provided by a TDR device 354 can be transmitted along the electrical conductor 346 via an electrical contact 363 (i.e. within the bore 228 of the casing 212). The TDR device 354 is provided as part of the cutting tool 326 (either separately or integrated) so that the TDR device 354 itself is introduced into the bore 228 along with the cutting tool 326. In addition, a processor 352 is provided with the TDR device 354 for analysing the transmitted and/or received signals downhole. An electrical connection 380 such as a serial link is provided for connecting the processor 352 and/or TDR device 354 to surface, where a PC 382 may be provided (e.g. for a user and/or for further analysis of information sent to surface from the processor 352). In addition, the casing strings 212a-212b may be electrically connected together using a casing tie 384. The casing tie 384 may ensure that any signal reflected from an end of the casing strings 212a-212b is reflected at the same time.
Various modifications may be made to the method, apparatus and tool described herein. At least one feature of one of the method, apparatus and/or tool may replace any corresponding feature in the other of the method, apparatus and/or tool. At least one feature of the method, apparatus and/or tool may be combined with any other method, apparatus and/or tool.
Although Figure 17 illustrates a wellhead 218 disposed on deck 216 of an offshore product rig 218, it will be appreciated that the wellhead 214 could be a subsea wellhead such that the apparatus 240 is at least partially deployed in a subsea setting. It will be appreciated that the well 210 could be an onshore or offshore well.
The cutting tool 10, 110, 326 may take any appropriate form. For example, the cutting tool 10, 110, 326 could use any appropriate technology such as abrasion, water abrasive cutting, explosive charges, mechanical cutting, or the like to sever the casing 212 / tubular 25, 125.
Although the processor is described as being configured to use the received/reflected signal(s) to determine progress of the cut through the casing 212, it will be appreciated that an operator may alternatively or additionally obtain information directly from a display (not shown) illustrating a waveform providing information regarding the received/reflected signal(s).
In an example, the TDR device 254, the casing 212, and/or any other part of the apparatus 240 may be grounded 256. It will however be appreciated that it may not be necessary to explicitly ground the apparatus2 40. For example, it may be possible to apply a positive potential to the electrical conductor 246 and a negative potential to the casing 212, or vice versa, and vary the potential difference to cause a signal to propagate along the electrical conductor 246 and/or casing 212.
It will be appreciated that the signal may propagate along the waveguide 258, which may include at least one of: the electrical conductor 246 and the casing 212. The signal may therefore propagate along at least one of the electrical conductor 246 and the casing. In an example, if the signal is injected into the electrical conductor 246, the signal may propagate along the electrical conductor 246. The propagation of the signal along the electrical conductor 246 may be supported by the casing 212, which together with the electrical conductor 246 may define the waveguide 258.
Although the electrical conductor 246 may be provided in the bore 228 of the casing 212, additionally or alternatively, the electrical conductor 246 may be provided as part of the casing 212 or another tubular. For example, an inner casing/tubular of a multiple casing string/tubular may be used as an electrical conductor for implementing the method and/or as part of the apparatus and/or tool as described herein. The inner casing/tubular may be insulated from an intermediate or outer casing/tubular of the multiple casing string/tubular such that a waveguide may be formed from the inner and outer casings/tubulars (and optionally any intermediate casings/tubulars if present). The electrical conductor of the casing/tubular may include an impedance matching device, for example, as described herein. The electrical conductor of the casing/tubular may include or be connectable to a clamping tool, for example, as described herein.
At least one method of determining progress of a cut through a casing of a well as well as associated apparatus is described herein. It will be appreciated that the method and/or associated apparatus could also be used to determine progress of a cut through any type of tubular, for example, piles, pipes, conductors and other onshore and offshore assets and infrastructure. Other onshore and offshore assets may include, for example, onshore and offshore wind turbines, offshore water turbines, or the like.
Various references are made to "downhole" and "uphole" directions (e.g. in a well). A skilled person will appreciate that the downhole direction may refer to a direction from surface to an end of the well and the uphole direction may refer to a direction from the end of the well to surface. A skilled person will appreciate that a well may include vertical, horizontal and/or inclined sections. Thus, in some well sections, the downhole direction may be either upwards, downwards, sideways or any inclination. Similarly, in some well sections, the uphole direction may be either upwards, downwards, sideways or any other inclination.
It will be appreciated that while in the above example, the cutting tool 226 and methods have been described with reference to cutting through casing for the purposes abandonment, it may be that in other example, the tools and method may be used for severing tubulars within a well or other structures for other reasons. For example, the tools and methods described may be used to retrieve tubulars, sections of coiled tubing, or the like (e.g. as part of retrieval operations for, but not exclusively, well infrastructure abandonment operations, or the like). A skilled reader will readily be able to implement the above tools and methods for determining cuts on other such tubulars.
A computer program may be configured to provide any of the above described methods. The computer program may be provided on a computer readable medium. The computer program may be a computer program product. The product may comprise a non-transitory computer usable storage medium. The computer program product may have computer-readable program code embodied in the medium configured to perform the method. The computer program product may be configured to cause at least one processor to perform some or all of the method.
Various methods and apparatus are described herein with reference to block diagrams or flowchart illustrations of computer-implemented methods, apparatus (systems and/or devices) and/or computer program products. It is understood that a block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions that are performed by one or more computer circuits. These computer program instructions may be provided to a processor circuit of a general purpose computer circuit, special purpose computer circuit, and/or other programmable data processing circuit to produce a machine, such that the instructions, which execute via the processor of the computer and/or other programmable data processing apparatus, transform and control transistors, values stored in memory locations, and other hardware components within such circuitry to implement the functions/acts specified in the block diagrams and/or flowchart block or blocks, and thereby create means (functionality) and/or structure for implementing the functions/acts specified in the block diagrams and/or flowchart block(s).
Computer program instructions may also be stored in a computer-readable medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instructions which implement the functions/acts specified in the block diagrams and/or flowchart block or blocks.
A tangible, non-transitory computer-readable medium may include an electronic, magnetic, optical, electromagnetic, or semiconductor data storage system, apparatus, or device. More specific examples of the computer-readable medium would include the following: a portable computer diskette, a random access memory (RAM) circuit, a read-only memory (ROM) circuit, an erasable programmable read-only memory (EPROM or Flash memory) circuit, a portable compact disc read-only memory (CD-ROM), and a portable digital video disc read-only memory (DVD/Blu-ray).
The computer program instructions may also be loaded onto a computer and/or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer and/or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the block diagrams and/or flowchart block or blocks.
It will be well understood by persons of ordinary skill in the art that whilst some examples or embodiments may implement certain functionality by means of a computer program having computer-readable instructions that are executable to perform the method of the embodiments, the computer program functionality could be implemented in hardware (for example by means of a CPU or by one or more ASICs (application specific integrated circuits), FPGAs (field programmable gate arrays) or GPUs (graphic processing units)) or by a mix of hardware and software.
Accordingly, the method, apparatus and/or tool may be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.) that runs on a processor, which may collectively be referred to as "circuitry," "a module" or variants thereof.
It should also be noted that in some alternate implementations, the functions/acts noted in the blocks may occur out of the order noted in the flowcharts. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Moreover, the functionality of a given block of the flowcharts and/or block diagrams may be separated into multiple blocks and/or the functionality of two or more blocks of the flowcharts and/or block diagrams may be at least partially integrated. Finally, other blocks may be added/inserted between the blocks that are illustrated.
The method and systems described above may use one or more techniques for measuring the extent of the cut. One of the techniques for measuring the extent of the cut, which may be used in addition to or as an alternative to the laser scanning and photogrammetry described above, may comprise using a signal reflected from at least one boundary defined by the tubular to determine progress of the cut through the tubular. The technique may be or comprise at least one feature of the technique described in GB 1714062.5 (publication number GB 2566068 ), in the name of the present applicants.
The technique may comprise using a signal reflected in the electrical conductor from at least one boundary defined by the tubular to determine progress of the cut through the tubular. The technique may comprise using the tubular and the electrical conductor as a waveguide for carrying the signal axially along the tubular and the electrical conductor. The waveguide may define an axial waveguide for allowing the signal to propagate along the waveguide, for example, in an uphole and/or downhole direction. The signal may be transmitted, reflected or re-reflected axially along the waveguide. The technique may comprise the transmitted and/or reflected signals. At least one signal may be reflected by at least one boundary. The electrical conductor may allow the propagation of a plurality of signals, for example, comprising the transmitted and reflected signals, as well as re-reflected signals (e.g. where a reflected signal is reflected by a boundary to form the re-reflected signal). If there are a plurality of boundaries, there may be a plurality of re-reflected signals, which may need to be analysed to determine which reflected signal may provide information relating to the cut. The boundary may be defined by a change in at least one electrical parameter along the electrical conductor. The parameter may comprise an impedance value of the electrical conductor at the boundary. The technique may comprise monitoring the reflected signal to measure a change in the signal reflected by the boundary. Monitoring the reflected signal may comprise comparing the transmitted signal with the reflected signal and determining whether any change in the received signal provides information relating to the progress of the cut. Monitoring the received signal may comprise determining at least one of: a change in a time delay between transmission of the transmitted signal and receipt of the received signal; and a change in a time-variant signal amplitude or waveform of the received signal.
In some embodiments, the measurement system is configured for linear motion relative to a planar/flat surface, e.g. with a linearly moving head of a cutting system (i.e. the cutting system moving translationally rather than rotationally). For example, the cutting system is arranged to form a longitudinal cut on a surface of a member which may comprise a cut through a planar/flat surface. The measurement system and cutting system may be arranged to form and measure a cut form in a translational movement and also a rotational movement. The member in which the cut is formed may be flat or planar or the surface may comprise an inner surface of a conduit which provides a flat or planar surface over a part of the (inner) surface.
In some further embodiments, the scan performed by the measurement system is conducted post-cut, i.e. the cut is formed by the cutting system and the measurement system operates once the cut has been formed (and the cutting operation has been completed/finished) such that the cut is not being formed at the same time as the measuring system is operable.
In embodiments, the shroud moves and/or specifically rotates (with the measurement system), for example in the same rotational plane as the cutting tool. In addition, if the cutting system is arranged to perform a longitudinal cut in the member and the cutting system moves translationally (for example over the flat/planar surface) then the shroud is also arranged to move translationally (e.g. in the longitudinal direction of the member which may be upwards and/or downwards) and moves with the measurement system.
While specific examples of the method, apparatus and/or tool have been described above, it will be appreciated that the method, apparatus and/or tool may be practiced otherwise than as described. The descriptions above are intended to be illustrative, not limiting. Thus it will be apparent to one skilled in the art that modifications may be made to the method, apparatus and/or tool as described without departing from the scope of the claims set out below.

Claims

A downhole cutting system (5) comprising:
at least one cutting tool (10);

a measurement system (40) configured to determine an extent, progress and/or geometry of a cut formed by the cutting tool (10) in a wall (30) of a tubular (25) or other member, and characterised in that:
a shroud (80) extends at least part of the way between the measurement system (40) and an interior wall of the tubular (25) or other member in use.
The system of claim 1, comprising a rotating head (15), wherein the at least one cutting tool (10) is mounted on or coupled with the rotating head (15) for rotation therewith; and the measurement system (40) is mounted on, coupled with or otherwise arranged to rotate with the rotating head (15) and/or the cutting tool (10).
The system of claim 1 or claim 2, wherein the measurement system (40) is in-line with the cutting tool (10) and/or the measurement system (40) is arranged to follow behind the cutting tool (10) when being rotated and wherein the cutting tool (10) is arranged such that it is rotated in a rotational plane around a rotational axis (20) and the measurement system (40) is arranged to rotate in the same rotational plane as the cutting tool (10).
The system of any preceding claim, wherein the measurement system (40) is located at the same distance longitudinally along the cutting system (5) or rotational axis (20) as the cutting tool (10) but is arranged such that it is located circumferentially around the rotational axis (20) relative to the cutting tool (10).
The system of any preceding claim, wherein the measurement system (40) comprises a laser scanner (45) and wherein the laser scanner (45) is configured to sweep a laser beam perpendicularly to the plane of rotation of the measurement system (40).
The system of claim 5, wherein the laser scanner (45) is configured to sweep the laser beam perpendicularly to and in the plane of rotation of the measurement system (40).
The system of any preceding claim, wherein the measurement system (40) is configured to:
determine positions of points on a surface of the cut (35) in the wall (30) of the tubular (25) or other member, and optionally also at least part of a surface of a wall (30) of the tubular (25) or other member adjacent to the cut (35), relative to the measurement system (40);

use the determined positions of the points on a surface to construct a 3D model or image of the cut (35) and to determine the geometry and/or extent or progress of the cut (35) from the 3D image or model;

determine if the cut (35) extends part of the way through the wall (30) of the tubular (25) or other member or all of the way through the tubular (25) or other member; and

wherein the measurement system (40) comprises one, two or more cameras (60) configured to collect images for use in stereo photogrammetry to determine the positions of points on the surface of the cut (35) in the wall (30) of the tubular (25) or other member.
The system of claim 7, the measurement system (40) comprises at least a pair of cameras (60) which are arranged spaced apart so as to perform stereo photogrammetry, which are used in addition to the laser scanner (45) to supplement the 3D model of the cut.
The system of any preceding claim, wherein the measurement system (40) is configured to use electrical techniques, such as impedance based techniques or time domain reflectometery, to determine the extent or progress of the cut (35).
The system of claim 9, wherein an electrical conductor (246) is provided in a bore (228) and the bore (228) is defined by the tubular (25, 212), and comprising a signal generator (248) for transmitting a signal along the electrical conductor (246) and a signal receiver (250) for receiving a signal reflected in the electrical conductor (246) from at least one boundary defined by the tubular (25) or other member, wherein a processor (252) is configured to use the received signal to determine progress of the cut (35) through the tubular (25) or other member.
The system of any preceding claim, wherein the cutting tool (10) comprises a fluid abrasive jet cutting tool and wherein the cutting system (5) comprises means for forming a vortex in the interior of the tubular (25) or other member.
The system of claim 11, wherein, a fluid nozzle and fluid guides are arranged to provide the vortex in the tubular.
The system of any preceding claim, wherein the cutting system (5) is configured to provide a fluid flow or fluid jet into a volume adjacent the measurement system (40) and/or proximate a portion of the cut (35) and wall (30) of the tubular (25) or other member being measured by the measurement system (40).
The system of any preceding claim wherein the shroud (80) extends between the cutting tool (10) and at least part of the measurement system (40).
The system of claim 13 or claim 14 when dependent upon claim 13, configured to provide the fluid flow or fluid jet into a volume at least partly enclosed by the shroud (80).
The system of any preceding claim wherein the shroud (80) defines an interior volume and the cutting tool (10) is provided outwith the interior volume.
A method of manufacturing, producing, assembling or repairing a downhole cutting system (5), the method comprising:
coupling or mounting at least one cutting tool (10);

coupling a measurement system (40) to the cutting tool (10) for movement therewith; wherein the measurement system (40) is configured to determine an extent, progress and/or geometry of a cut (35) in a wall (30) of a the tubular (25) or other member formed by the cutting tool (10); and characterised by

mounting a shroud (80) to or around at least part of the measurement system (40) in order for the shroud (80) to extend at least part of the way between the measurement system (40) and an interior of the tubular (25) or other member, in use.