GB2558172A

GB2558172A - A method for cleaning drill pipe

Info

Publication number: GB2558172A
Application number: GB1606224.2A
Authority: GB
Inventors: Fraser John
Original assignee: Cherish Bodman; Coretrax Technology Ltd
Current assignee: Cherish Bodman; Coretrax Technology Ltd
Priority date: 2016-04-12
Filing date: 2016-04-12
Publication date: 2018-07-11
Anticipated expiration: 2036-04-12
Also published as: GB2558172B; GB2558172A8

Abstract

A method of cleaning the internal diameters of drill pipe comprises of a cleaning tool 1 comprising a cleaning element such as radially extending bristles 4; the overall mass of the tool overcomes the buoyancy and friction force of the fluid in the pipe and allows the cleaning tool to fall through the pipe under its own weight; the method further comprises a landing sub 7 (Figure 4) with an internal profile which catches and prevents the tool from travelling further down the pipe. The tool may comprise a handle 2 and a nose 5. The tool can be uncoupled so that different sections can be replaced. The cleaning tool may comprise a tracking device so that it can be located in the pipe.

Description

(71) Applicant(s):

Cherish Bodman

Coretrax Technology Limited, Technology House, Moss Road, Gateway Business Park, ABERDEEN, AB12 3GQ, United Kingdom

John Fraser

Coretrax Technology Limited, Moss Road, Gateway Business Park, ABERDEEN, Grampian, AB12 3GQ, United Kingdom (56) Documents Cited:

RU 002495995 C1 US 3329211 A

US 3251306 A US 3034581 A

US 2509492 A US 2203966 A

US 20120198637 A1 (58) Field of Search:

INT CL B08B, E21B, F16L

Other: WPI, EPODOC, Patent Fulltext

Jason Fong

Coretrax Technology Limited (Incorporated in the United Kingdom)

Technology House, Moss Road,

Gateway Business Park, ABERDEEN, AB12 3GQ, United Kingdom (72) Inventor(s):

John Fraser (74) Agent and/or Address for Service:

Cherish Bodman

Coretrax Technology Limited, Technology House, Moss Road, Gateway Business Park, ABERDEEN, AB12 3GQ, United Kingdom (54) Title of the Invention: A method for cleaning drill pipe Abstract Title: A method of cleaning a drill pipe (57) A method of cleaning the internal diameters of drill pipe comprises of a cleaning tool 1 comprising a cleaning element such as radially extending bristles 4; the overall mass of the tool overcomes the buoyancy and friction force of the fluid in the pipe and allows the cleaning tool to fall through the pipe under its own weight; the method further comprises a landing sub 7 (Figure 4) with an internal profile which catches and prevents the tool from travelling further down the pipe. The tool may comprise a handle 2 and a nose 5. The tool can be uncoupled so that different sections can be replaced. The cleaning tool may comprise a tracking device so that it can be located in the Pipe-

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

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Figure 2

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Figure 3A

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Figure 3B

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Figure 4

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Figure 5

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Figure 6

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Figure 7

A METHOD FOR CLEANING DRILL PIPE

FIELD OF THE INVENTION

The present invention relates to a wellbore cleaning element and more specifically a method of cleaning the internal diameters of pipe. The pipe can comprise a drill pipe, tubular or conduit used in oil and gas drilling and recovery operations. The invention relates to a process of cleaning and removing residual debris from such pipe.

BACKGROUND OF THE INVENTION

There are numerous instances where cementing operations are required including during the plugging and abandoning of wells. An example of which is following the drilling of a wellbore, cementing operations take place to ensure that the annulus is sealed after a casing string has been run in the wellbore to prevent water penetration into the well. Cementing operations usually take place through drill pipe, tubing or conduit where cement slurry is pumped into the well and fills the space between the casing and the wellbore. After such operations, it is imperative that the bore of the drill pipe, tubular or conduit is free from debris to ensure further operations are unaffected. Typically, cleaning the bores of drill pipe, tubing or conduit is done by pumping foam rubber elements (typically spherical), known as wiper balls, from surface through the bore of the drill pipe, tubular or conduit and out the open end. The elements are made from a resilient rubber compound which has the ability to compress and squeeze through small restrictions while also able to expand back to its original size and shape. The outer diameter of these elements are typically larger than the internal diameter of the drill pipe, tubular or conduit. For example, drill pipe with a bore of 3 inches requires a wiper ball of 6 inches to create a friction fit. So when inserted and displaced through the bore, the constant outward biasing force wipes, cleans and removes any residual cement and debris from the drill pipe, tubing or conduit walls. The foam rubber element travels through the drill pipe, tubing or conduit and out the open end before being circulated back to surface with the debris.

Additionally, during abandonment operations a cement plug is set to provide zonal isolation to aid in the prevention of gas and pressure migration. Normally after the cementing operation is complete, with the cement plug placed at the desired depth, the end of the drill string, tubing or conduit is still submerged in the cement. To prevent cement disturbance, a foam rubber element cannot be pumped through the bore until drill pipe, tubing or conduit is pulled out of hole to clear the top of the cement. Once cleared, a foam rubber element can then be deployed from surface. This means that the foam rubber element will not have cleaned the bore of the recovered drill pipe, tubing or conduit. To ensure it is debris-free, the recovered drill pipe, tubing or conduit will have to be re-run back in the hole and a foam rubber element deployed from surface.

The process of pulling the drill pipe out of hole and re-running it at a later date to be cleaned is not only time consuming but also costly to the operator. The following invention allows the internal walls of the drill pipe, tubing or conduit to be cleaned prior to pulling out of hole and without disturbing cement.

Therefore, a device is required which is inserted into drill pipe, tubing or conduit from surface to agitate and clean the bore without disturbing cement. The device is dropped from surface and under its own weight, it will free fall through the drill pipe, tubing or conduit. An integral cleaning element such as brushing bristles will ensure that the bore of the pipe is cleaned effectively whilst providing the flexibility to pass through any restrictions such as tool joints. The mass of the tool will overcome friction generated from the bristles and the buoyancy of the well fluid. A landing sub with a profiled internal upset positioned at the required depth from surface will catch and prevent the tool from travelling further down the string.

Preferred embodiments of the invention seek to overcome one or more of the above disadvantages of the prior art.

SUMMARY OF THE INVENTION

Accordingly to a first aspect of the present invention, there is provided a method for cleaning the internal diameter of a pipe, the method comprising;

A tool consisting of a weighted bull nose with a tapered leading edge profile connected to a mandrel section incorporating the cleaning element where it travels through the elongate member string under its own weight and,

A landing sub which is selectively connectable to the elongate member string wherein it prevents the tool from travelling further through the elongate member string by a tapered internal upset profiled to match the bull nose and,

A method of tracking the location of the cleaning element within the elongate member string after it has been dropped from surface and the cement operation complete.

Hereinafter, forthe sake of brevity, the term pipe will be used in the present application for denoting the elongate member string and string of tubulars such as a drill pipe string, tubing or conduit.

Preferably, the tool does not require well fluid or pressure to displace through the bore of the pipe, thus providing the advantage that it minimises cement disturbance as well as removing the need for the pipe to be connected to the rig pumps. Optionally, the tool is caught from travelling out the elongate member string by a landing sub, further minimising cement disturbance.

Optionally, the tool consists of 3 parts - handle, core and bull nose. The handle is positioned on the upper section of the tool and allows the operator to grasp and launch the tool from surface through the elongate member string and enable easy removal when recovering the cleaning tool. The core consists of a cleaning element, which dislodges and removes debris from the bore of the elongate member string. A bull nose is mounted on the lower section of the tool to centralise and provide sufficient mass to allow the tool to fall through the bore.

Optionally, the tool is able to fall through the bore of the elongate member string under its own weight. Preferably, the tool is able to fall through the bore of the elongate member string under its own weight through fluid. Optionally, through bores on the bull nose and mandrel provide fluid bypass channels to prevent the tool from surging orfloating due to the buoyancy of the fluid in the elongate member string.

The bull nose has a slightly smaller outer diameter than the bore of the elongate member string to ensure the tool is centralised while it is travelling through the bore.

The tool has the ability to dislodge and remove debris from the internal walls of the elongate 25 member string. Optionally, debris removal is done by dislodging debris via a brushing element. More optionally, the brushing element consists of a plurality of bristles which may be formed from plastic, metal or a composite material. Any other suitable compound may be used which allow recoverable deformation that is strong enough to withstand the stresses occurring during the cleaning operation. More optionally, the material can be tailored to specific applications and elongate member string conditions.

Optionally, the length of bristles radially extend equal to or larger than the internal diameter of the elongate member string to ensure that the bristles provide a biasing force to dislodge any debris present in the bore.

Optionally, the core ofthe brushing element may be formed by a plurality of axially extending metal wires where bristles are intertwined between the wires. Each axial end of wire would rotate in opposite directions. When wound, the bristles form a radially outward protruding helical/spiral arrangement. Optionally, the axial ends ofthe core can be permanently fixed to cylindrical discs. More optionally, the discs can be further secured to the handle and a bull nose via a screw thread. Advantageously, the use of screw threads allows ease of replacement should the core brush need to be replaced. Optionally, the axial ends can be integral to the handle and bull nose.

Optionally, the bristles are mounted along and around an axially extending cylindrical body.

Advantageously, the arrangement of the bristles can be offset from each row to allow 360 degree coverage ensuring that the entire bore ofthe drill pipe is clean.

Optionally, the bull nose and mandrel section are connected via a thread which houses the brushing element. Optionally, the brushing element consists of a removable/replaceable cylindrical sleeve. Advantageously, the brushing element can be easily removed and replaced if past its service life. Optionally, the cylindrical sleeve slides onto a mandrel. The upper portion ofthe mandrel has a protruding upset and the bull nose screws onto the lower portion of the mandrel which retains and prevents the sleeve from axial movement.

Optionally, bristles are contained and permanently secured in the bores on the cylindrical sleeve using mechanical fasteners or adhesive.

Advantageously, the cleaning element is prevented traveling further down the elongate member string via a landing sub with a tapered internal upset, where the internal upset matches a profile on the bull nose ofthe mandrel. The landing sub is made up to the elongate member string via a standard oilfield connection. Preferably, the internal upset is part of the landing sub as a one-piece design to limit the number of parts. More preferably, the internal upset is positioned in the landing sub so when the tool is caught in the profile, there is sufficient space for the operator to retrieve the tool.

Optionally, the location of tool can be tracked in the elongate member string as it is pulled out of hole. This is useful especially if the tool has encountered a restriction or obstruction which prevents it from reaching the landing sub. Optionally, tracking can be done by a tagging device such as but not limited to Radio Frequency Identification (RFID). A tag, or similar can be mounted onto the tool before it is dropped through the elongate member string. While pulling the pipe out of hole, a reader system at surface can be used to scan the elongate member string ensuring the tool is not trapped prior to being caught in the landing sub. If the tag is detected, the operator will be notified that the tool is trapped and any subsequent elongate member strings will not have been cleaned.

Optionally, another method of locating the tool is using a length of wire or rope with a weighted mass which is attached to the bull nose of the tool. The length of string or wire is to be longer than a joint of elongate member string, typically 30 feet. If the tool encounters an obstruction, the weighted mass will be visible at the end of the joint of elongate member string and visible to the operator indicating it has not reached the landing sub.

The various aspects of the present invention can be practiced alone or in combination with one or more of the other aspects, as will be appreciated by those skilled in the relevant arts. The various aspects of the invention can optionally be provided in combination with one or more of the optional features of the other aspects of the invention. Also, optional features described in relation to one example can optionally be combined alone or together with other features in different examples of the invention.

Various examples and aspects of the invention will now be described in detail with reference to the accompanying Figures. Still other aspects, features and advantages of the present invention are readily apparent from the entire description thereof, including the Figures, which illustrate a number of exemplary aspects and implementations. The invention is also capable of other and different aspects and implementations, and its several details can be modified in various aspects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be constructed as limiting in scope.

Language such as including, comprising, having, containing, or involving, and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term comprising is considered synonymous with the terms including or containing for applicable legal purposes.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings, in which:

Figure 1 is a schematic front view of the preferred cleaning tool;

Figure 2 is a schematic front view of the preferred cleaning tool showing preferred helical bristling;

Figure 3A and Figure 3B are schematic views of the core and bristle arrangement prior to the wires being twisted

Figure 4 is a sectional front view of the elongate member string and landing sub 10 showing the internal upset profile which matches the profile of the leading edge of the tool of Fig 1;

Figure 5 is a schematic front view of tool caught in the landing sub after it has be dropped through the elongate member string;

Figure 6 is a schematic front view of an alternate embodiment of the cleaning tool 15 with optional brush sleeve where it can be replaced if the bristles are too worn;

Figure 7 is a schematic sectional front view of the elongate member string pulled out of the wellbore and a location device tracking the cleaning tool which has encountered debris blockage preventing it from reaching the landing sub.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 shows a schematic front view of the preferred embodiment of the cleaning tool 1. Preferably, the cleaning tool 1 consists of a handle 2, a core 3 which contains bristles 4 and a bull nose 5. The cleaning tool is of cylindrical shape so it is able to pass through the bore of the pipe. Optionally, a further bull nose 5 can also be mounted on the upper portion of the cleaning tool 1 to increase the overall mass should there be heavy weight fluid in the elongate member string. Optionally, the outer diameter of the bull nose 5 can be sized to drift the internal diameter of the pipe, thus providing a secondary function of ensuring that the bore of the pipe has been checked and drifted to the correct diameter. More optionally, the bull nose 5 can be mounted on the upper portion of the cleaning tool 1 instead of the lower portion if the outer diameter is sized to drift the pipe. This prevents the bull nose from encountering any debris and potentially getting trapped in the bore of the pipe.

The bristles 4 can be made from but not limited to a plastic compound where it is able to withstand the mechanical forces of agitating debris from the internal walls of the pipe as well as withstanding the thermal environment down hole. Furthermore, the bristle 4 material will have to be rigid enough to dislodge debris which has built up in the bore but also flexible enough to minimise friction and pass through any restrictions while falling through the pipe under its own weight. Alternative materials such as steel or a high memory polymer can be used providing that the overall mass of the tool 1 overcomes the friction of the bristles and buoyancy of the well fluid.

Figure 2 shows a schematic front view of the preferred embodiment showing the preferred bristle arrangement. The arrangement of the bristles 4 is important as it determines the cleaning capability. In the preferred embodiment, the bristles 4 are arranged in a helix/spiral shape which radially protrudes outwards from an axial extending core 3 and provides 360 degree coverage while providing a path for fluid bypass. Preferably, the length of bristles 4 radially protrude outwards with a diameter larger than the internal diameter of the pipe. The interference fit between the bristles and the bore should allow sufficient cleaning ability as well as minimal friction.

The bull nose 5 comprises a plurality of through bores 6 which provide a path for well fluid to pass. Preferably, the through bores are sized to allow sufficient flow area past the cleaning tool. This aids the cleaning tool 1 in falling through the elongate member string under its own weight and prevents a surging effect while traveling through the bore. Preferably, the bull nose is made from a metallic material such as but not limited to steel which has a high density as well as strength. The bull nose has a tapered leading edge which prevents the tool from hanging up in the bore of the pipe if it encounters any stubborn debris. Additionally, the tapered leading edge of the bull nose matches the tapered internal profile on the landing sub.

Optionally, the cleaning tool 1, consisting of 3 parts wherein the core 3 can be selectively connectable to the handle 2 and the bull nose 5. This provides the ability to remove and replace the core 3 once the bristles are too worn and past their service life. The method of retention can be but not limited to a screw thread where the fastening method is not permanent. In the preferred embodiment, the core 3 is retained by the handle 2 and the bull nose 5 by a screw thread 6 and secured with set screws. Further optionally, the cleaning tool 1 can have an integral handle 2 and bull nose 5 wherein the core 3 is secured via a permanent fastening methods such as welding or similar.

Figure 2 shows a schematic front view of the cleaning tool 1 with the wires and bristles intertwined to form the helical core 3. Preferably, the helical arrangement is made by rotating the axial ends of the core in opposite directions which intertwine the bristles and the wire to form radially outwardly extending bristles. The number of helixes is determined by the number of rotations of the core. Optionally, for certain applications the diameter of the radially extending bristles can vary along its longitudinal axis with the diameter being smaller at the bull nose end and increasing in diameter towards the handle end.

Figure 3A shows a schematic front view of the preferred embodiment of the core 3 and the bristles 6 prior to being intertwined and creating a helix/spiral arrangement. This preferred arrangement provides complete 360 degree coverage of the internal walls of the pipe. The helix arrangement extends along the core's 3 longitudinal axis. Additionally, the arrangement provides sufficient fluid bypass around the tool which prevents the tool from surging. The number of bristles 4 is variable depending on the application. In the preferred embodiment, the bristles 4 are arranged offset at 90 degrees from each other prior to them being intertwined, as shown in Figure 3B. The core can be manufactured from either a single length of wire or a plurality of wires intertwined together. The wire can be made from any material which has good structural integrity in the axial direction. Preferably, the wire material is to be made from metal, more specifically steel or steel alloy.

The landing sub made up to the drill pipe is depicted in Figure 4. Preferably, the landing sub 7 is made up to the drill pipe 8 at the required depth from surface. An internal profile 9 is shaped to prevent the cleaning tool from travelling further down the pipe. In the preferred embodiment, the internal profile 9 has a tapered reduced internal diameter compared to the internal diameter of the pipe. This allows fluid to pass through the landing sub but does not allow the cleaning tool to travel further through the pipe. More preferably, the internal profile 9 is integral to the landing sub 7 and to minimise the risk of losing down hole. Preferably, the position of the internal profile 9 in the landing sub 7 allows the cleaning tool to be retrieved by the operator once the tool has completed the clean-up of the pipe. In the preferred embodiment, the position of the internal profile 9 from the upper end of the landing sub 7 is shorter than the overall length of the cleaning tool.

Figure 5 shows a schematic front view of the cleaning tool 1 in the preferred embodiment caught by the internal profile 9 in the landing sub 7 as it has made its way through the pipe 8 and completed the cleaning operation. Once the pipe 8 is pulled back to surface, the portion of pipe above the landing sub 7 is broken to expose the cleaning tool 1. At this point the operator can retrieve the cleaning tool via the handle.

A schematic front view of an alternative embodiment of the cleaning tool is shown in Figure 6. The cleaning tool consists of 3 parts - a mandrel 10, a brush sleeve 11 and a bull nose 5. In this alternative embodiment, the brush sleeve 11 is a cylindrical tube which has a through bore to allow the sleeve to slide over the mandrel 10. The mandrel 10 has an integral handle to allow the operator to grasp for launching and retrieving the tool from the pipe. A bull nose 5, similar to the preferred embodiment, is selectively coupled to the mandrel 10 via a screw thread 12 and secured by a pair of set screws 13.

Preferably, the brush sleeve contains a plurality of blind bores arranged radially around the outer diameter and also along its axial length. Bristles 4 which radially extend outwards from the sleeve 11 are mounted and secured inside the bores by a mechanical fastener and/or adhesive. The mechanical fastener can be but not limited to a staple which allows insertion into the bore and prevents removal by anchoring against the bore walls. The adhesive must be strong enough to retain the bristles as well as withstanding thermal and chemical reaction from the well fluid. Preferably, a combination of mechanical and adhesive fastening methods are used. Optionally, each row of bores are offset from each other to create a complete 360 degree coverage of the bore of the pipe. Preferably, the arrangement of bores can be helical where it still provides 360 degree coverage while maximising fluid bypass around the brush sleeve, minimising surging as it is run through the bore. The helical arrangement is created by offsetting each row of bores and skipping bores for every set.

Advantageously, the brush sleeve 11 is able to be removed from the mandrel 10 should the bristles 4 become too worn for operation. The brush sleeve 11 is preferably made from an aluminium alloy but can be made from any other suitable material such as steel alloy, plastic or composite. The material must be able to withstand the thermal environment in the wellbore as well as mechanically strong enough to retain the bristles.

Figure 7 shows a schematic front view of a method of locating the cleaning tool should the cleaning tool be trapped by an obstruction 14 in the pipe. The obstruction 47 could be debris present in the bore. Optionally, an RFID 15 (radio frequency identification) tag is mounted on the cleaning tool. A reader/scanning device 16 detects the tag and notifies the user that the

While the pipe is pulled out of hole, a reader/scanning device 16 is ran alongside the pipe 8 scanning to ensure that the cleaning tool 1 has not encountered a restriction 14 preventing it from traveling to the landing sub.

Further modifications and improvements may be made to the embodiments hereinbefore described without departing from the scope of the invention.

Claims

CLAIMS It is claimed that:

1. A method for cleaning the internal diameters of pipe, the method comprising:

A cleaning tool containing a cleaning element such as but not limited to radially 5 extending resilient bristles;

A cleaning tool which is able to be inserted into the internal diameter of pipe from surface and fall through under its own weight;

A cleaning tool which has the ability to allow fluid to bypass;

A landing sub which contains an internal profile designed to catch and prevent the 10 cleaning tool from travelling further down the pipe; and

An optional tracking device where it is able to locate the position of cleaning tool in the pipe.

2. A method as claimed in claim 1, including arranging the bristles to ensure complete 360 degree coverage of the internal diameter of the pipe and the bristles having at

15 least the same or larger diameterthan the pipe to ensure constant biasing force aiding in debris removal.

3. A method as claimed in claim 1, including having the overall mass of the cleaning tool heavy enough to overcome the buoyancy factor of the fluid in the pipe and friction

20 factor of the bristles acting against the pipe walls.

4. A method as claimed in claim 2, including bristling material to be of a resilient material such as but not limited to a plastic compound with good mechanical properties and high memory to withstand the forces encountered when dislodging debris from the

25 internal walls of drill pipe and any restrictions.

5. A method as claimed in claim 1, including an internal profile on the landing sub where the diameter is reduced compared to the upper section of the landing sub, and the internal profile has a tapered leading edge to accommodate the leading edge of the bull nose.

6. A method as claimed in claim 1, a tool consisting of a handle, core and bullnose where the handle is knurled to allow ease of grasp for the operator, a core containing the

5 bristling and a bullnose which centralises the tool as it passes through the pipe, contains the majority of the mass and helps travel down to the landing sub, contains through bores which enable fluid bypass ensuring it does not surge the fluid in the pipe as outlined in claim 1.

7. A method as claimed in claim 6, wherein the tool can be selectively uncoupled to allow

10 replacement parts or permanently fastened.

Intellectual

Property

Office

Application No: GB 1606224.2 Examiner: Mr Jorge Quintero