WO2017001662A1

WO2017001662A1 - Method and tool for stepwise expansion of well tubulars

Info

Publication number: WO2017001662A1
Application number: PCT/EP2016/065504
Authority: WO
Inventors: Walter STAM
Original assignee: Shell Internationale Research Maatschappij B.V.; Shell Oil Company
Priority date: 2015-07-01
Filing date: 2016-07-01
Publication date: 2017-01-05

Abstract

An expansion tool for stepwise and sequential downhole expansion of a well tubular with two expansion cones (12, 112) moved in a caterpillar mode comprises: - a carrier body (101) which carries a first expansion cone (12), a second expansion cone (112) having a larger outer width than the first expansion cone (12) and a first, second and third expandable gripper (3, 22A, 22B) which are slidably mounted on the carrier body (101) above, between and below the expansion cones (12,112); - drilling fluid actuated piston and cylinder assemblies for inducing the grippers (3, 22A, 22B) to sequentially slide relative to the carrier body (101) in a caterpillar mode, thereby: - alternatingly pulling and pushing the expansion cones (12, 112) through the tubular (100); and - inducing the first expansion cone (12) to expand at least a substantial part of the tubular (100) initially to a first expanded width and inducing the second expansion cone (112) to expand at least a minor part of the tubular (100) to a larger width than the first expanded width.

Description

METHOD AND TOOL FOR STEPWISE EXPANSION OF WELL TUBULARS

BACKGROUND OF THE INVENTION

The invention relates to a method and tool for stepwise expansion of well tubulars .

A known well tubular expansion system and tool are disclosed in International patent application

WO2012104257.

In this known method a well tubular is expanded by pulling an expansion cone therethrough.

Known hydraulically actuated expansion methods for stepwise expansion of well tubulars are disclosed in US patents 7, 497, 255, 7,640,976 and 7,493,946 and

International patent application WO02/086285.

No commercial hydraulic well tubular expansion tools are currently available that:

1) Can switch the expansion mode from expansion in compression to expansion in tension. This enables expansion initiation i.e. the release from the starter joint by means of expansion in compression. It enables the expansion of the overlap in tension, whereby the cone can be pushed out of the liner. Switching from expansion in compression to tension reduces liner shortening. Expanding in compression instead of tension reduces wall-thickness reduction and therefore pipe strength reduction. Expansion mode can be chosen when expanding into the overlap, whereby the most favorable expansion mode is selected based on connection strength in compression and tension.

2) Can be utilized for both bottoms-up and top- down expansion. Liner installation feasibility is independent from the rigs over-pull capacity.

3) Can increase the forming limit of an expandable liner when running the expansion tool . 4) Can be utilized for expansion into the overlap without freezing in liner tension equal to the

expansion force, which is the case when expanding by rig pull or hydraulic expansion. This favors the collapse resistance of the expanded liner after the installation .

There is a need for an improved downhole well tubular expansion system that meets these objectives and overcomes drawbacks of known systems.

SUMMARY OF THE INVENTION

In accordance with the invention there is provided a method for downhole expansion of a well tubular, the method comprising:

- providing an expansion tool comprising a carrier body which carries a first expansion cone, a second

expansion cone having a larger outer width than the first expansion cone and a first, second and third expandable gripper, which are slidably mounted on the carrier body above, between and below the expansion cones;

- suspending the expansion tool from a drill string in a well at one end of the well tubular;

- activating drilling fluid actuated piston and cylinder assembly to induce the grippers to

sequentially slide relative to the carrier body in a caterpillar mode, thereby:

- alternatingly pulling and pushing the expansion cones through the tubular; and

- inducing the first expansion cone to expand at least a substantial part of the tubular initially to a first expanded width and inducing the second expansion cone to expand at least a minor part of the tubular to a larger width than the first expanded width. Optionally, the first and second expansion cones are both moved through substantially the entire length of the tubular, thereby expanding the entire tubular to the larger width generated by the second expansion cone .

The expansion tool may be induced to move in upward direction from a lower end to an upper end of the tubular or in in downward direction from an upper end to a lower end of the tubular.

In accordance with the invention there is also provided an expansion tool for downhole expansion of a well tubular, comprising:

- a carrier body which carries a first expansion cone, a second expansion cone having a larger outer width than the first expansion cone and a first, second and third expandable gripper, which are slidably mounted on the carrier body above, between and below the expansion cones ;

- a connector for connecting the expansion tool to a drill string in a well at one end of the well tubular;

- drilling fluid actuated piston and cylinder

assemblies for inducing the grippers to sequentially slide relative to the carrier body in a caterpillar mode, thereby, when in use:

- inducing the first expansion cone to expand at least a substantial part of the tubular initially to a first expanded width and inducing the second expansion cone to expand at least a minor part of the tubular to a larger width than the first expanded width.

These and other features, embodiments and

advantages of the expansion method and tool according to the invention are described in the accompanying claims, abstract and the following detailed description of non-limiting embodiments depicted in the

accompanying drawings, in which description reference numerals are used which refer to corresponding

reference numerals that are depicted in the drawings.

Similar reference numerals in different figures denote the same or similar objects. Objects and other features depicted in the figures and/or described in this specification, abstract and/or claims may be combined in different ways by a person skilled in the art .

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1-4 show how the expansion tool according to the invention moves stepwise up through a well tubular :

Figure 5 shows how the expansion tool according to the invention moves stepwise down through a well tubular ;

Figure 6 shows a longitudinal sectional view of an upper section of the expansion tool according to the invention ;

Figures 6A-C are enlarged sectional views of sections AA, BB and CC of the tool shown in Figure 6; Figure 6D is further enlarged sectional view of section DD shown in Figure 6C; and

Figures 7A-H shown how the upper section of the expansion tool shown in Figure 6 moves stepwise through a well tubular that is expanded thereby in two stages.

DETAILED DESCRIPTION OF THE DEPICTED EMBODIMENTS

Figures 1-4 show a two stage expansion system and is named TALTEM tool (Tandem Alterable Expansion Mode tool) . It has the potential to mount another similar hydraulic expansion tool with a slightly larger secondary expansion cone without an additional upper gripper system (AA) below the ALTEM tool shown in Figures 6 and 7.

The expansion process is realized in two steps by means of two differently sized cones 12 and 112. The upper gripper (3) needs to transmit a relative low expansion load due to the liner weight that acts on the cone. This means that the upper gripper (3) needs to push and expand the liner over both expansion cones (12 and 112) . If the intermediate gripper (22A) and the lower grippers (22B) are inside the expanded liner the system pressure can be increased to deactivate the upper gripper (3) and to activate both lower grippers 22A and 22B (as shown in Figure 7F) . Subsequently when pressure is applied the intermediate and lower grippers (22B and 22C) these are activated and the cone (12) is pushed in upward direction (L) . Upward liner movement is now prevented by the lower grippers (22) .

In step L illustrated in Figure 4 the liner also referred to as tubular (100) is now expanded in tension and is pulled over the cone (12) . After expanding through and activating of the open hole anchor (29) it is possible to continue expansion in tension by rig pull only (as the ALTEM tool in G) .

The TALTEM system configuration shown in Figures 1-4 has the following advantages : It doubles the expansion force capacity without compromising stroke length or operating pressures. However lubrication coating thickness at the second cone is less resulting in a higher friction loss and therefore higher

expansion forces are expected. Lower tensile loading on expanded connections. If an expanded connection is located between the expansion cone and lower gripper system it will see a tensile load, which is equal to the expansion force. This load is now divided in half, which enables higher forming limit for expandable liners. Lubrication conditions at the second expansion cone are deteriorated, which results in a higher friction between expandable liner and expansion cone. This higher friction would suppress local necking effects at relatively high expansion ratios, which improves the formability of expandable liners. The weight of the liner is normally carried by the starter joint (14), which shoulders on the expansion cone face. In the TALTEM system the first cone will be smaller compared to the ALTEM system. This smaller cone has a smaller cone face and can therefore carry less liner weight. It would require an additional technical solution to carry the same buoyant liner weight as in with the ATLEM system. A potential solution could be an additional shoulder in the liner in front of the upper gripper (3) . The body of the gripper (3) could act as a pilot cone, which expands this shoulder when the ATLEM tool is hydraulically activated. Alternatively a relatively large cone can be used as primary cone. This would result in a different expansion force between the cones, whereby the secondary cone expands the liner earlier and faster than the primary cone at a certain pressure. In this situation the secondary cone would shoulder earlier at its end position. Technically this is not an issue, because pipe shortening comes from above and the liner will not move relative to both gripper systems. When selecting cone sizes it is important to take the difference in lubrication conditions into account in order to prevent that the primary cone would expand the liner faster than the secondary cone due to less friction losses. Expansion force of the secondary cone should always be lower than the primary cone to mitigate this effect. However the available coating layer for the secondary cone will be less resulting in more friction losses and therefore higher expansion forces.

Descriptions above are based on a bottoms-up expansion approach. However the ALTEM & TALTEM tool also enables top-down expansion, whereby the liner weight is carried by the upper gripper system AA, which than becomes the lower gripper (M) . The ALTEM & TALTEM tool are run upside down when top-down expansion is required, whereas the tool functionality stays the same .

Figures 6 and 7 show an upper section of the MALTEM tools shown in Figures 1-5, which upper section provides a tool that enables pipe expansion in

different expansion modes in order to construct a (16 inch) monodiameter well and it's named "the ALTEM tool" (Alterable Expansion Mode tool) .

This upper section of the tool consists out of the following parts:

Part nr. 1) Drill pipe/inner rod. All parts with a dark grey color in the figures are fixed and can't slide relative to the drill pipe i.e. inner rod (1) .

Part nr. 2) Fixed inner body upper gripper system. This inner body constrains and enables sliding of gripper segments (3), it centralizes the tool relative to the liner and it is optional to use this inner body as pilot cone to expand an additional shoulder inside the liner, which partly carries the weight of the liner. Part nr. 3) Sliding gripper segments upper gripper system. These segments create an anchor between liner and drill pipe. Anchor segments bite through the coating by means of sharp teeth, it enables the expansion of the liner in compression and its gripping range covers ID variations based on API pipe tolerances.

Part nr. 4) Pins upper gripper system. These pins constrain the gripper segments (3) relative to the fixed inner body (2) .

Part nr. 5) Release spring upper gripper system. This spring pushes the gripper segments (3) inward when the shear pins (10) of the gripper release sub are sheared .

Part nr. 6) Activation spring upper gripper system. This spring energizes the gripper segments (3) against the liner via the segment retainer mandrel (7) . Part nr.7) Segment retainer mandrel upper gripper system. This retainer constrain the gripper segments (3) and transmits the spring load of the activation spring (6) to the gripper segments (3) .

Part nr. 8) Fixed inner body gripper release sub. This inner body constrains the outer body (9) of the gripper release sub via shear bolts (10) and it enables an end shoulder for the hydraulic jack when the shear bolts (10) are sheared and the gripper release sub is deactivated.

Part nr. 9) Outer body gripper release sub. This outer body acts as a shoulder for the activation spring (6), it enables an end shoulder for the hydraulic jack when the upper gripper system is active and it

deactivates the upper gripper by unloading the

activation spring (6) when the shear pins (10) of the gripper release sub are sheared.

Part nr. 10) Shear bolts gripper release sub. These bolts transmit the spring load of the activation spring (6) to the fixed inner body (8) via the outer body (9), it transmits the load of the hydraulic jack to the fixed inner body (8) via the outer body (9) at the end of its stroke and when sheared it releases the spring load of the activation spring (6) and thereby

deactivates the upper gripper system.

Part nr. 11) Near cone stabilizer. This stabilizer centralizes the expansion cone relative to the liner and it shoulders against the outer body (9) of the gripper release sub at the end of a stroke.

Part nr. 12) Expansion cone, which expands the liner to a larger diameter and it guides the jack piston (13) over the inner rod (1) . Part nr. 13) Jack piston. This piston pushes the expansion cone (12) through the liner when sufficient hydraulic pressure is applied via flow ports (18) inside the drill pipe (1) . Part nr. 14) Starter joint carries the buoyant weight of the liner by shouldering against the cone face of the expansion cone (12) .

Part nr. 15) Fixed cone nut, which guides the jack piston (13) relative to the drill pipe (1), it enables an end shoulder for the jack piston (13), it enables a shoulder for the expansion cone (12) during a straight pull and it contains communication channels to prevent trapped pressures.

Part nr. 16) Non return valves. These valves prevents u-tubing of cement into the drill pipe / liner annulus and it fills up the annulus below the expansion cone (12) during a straight pull.

Part nr. 17) Fixed jack cylinder. This cylinder contains the hydraulic pressure in order the push the jack piston (13) outward and it constrain the gripper piston (26) via shear pins (19) . Part nr. 18) Flow ports, which enables

communication via the drill pipe (1) with the hydraulic jack .

Part nr. 19) Shear pins lower gripper. These pins constrain the gripper piston (26) when the upper gripper system is active and when sheared it enables displacement of the gripper piston (26) .

Part nr. 20) Pins lower gripper system. These pins constrain the gripper segments (21) relative to the fixed inner body (22) .

Part nr. 21) Gripper segments lower gripper system. These segments create an anchor between liner and drill pipe. Anchor segments bite through a relative thin coating layer by means of sharp teeth. It enables the expansion of the liner in tension and its gripping range is well defined by the diameter of the expansion cone (12) .

Part nr. 22) Sliding inner body lower gripper system. This inner body constrains the gripper segments (21) and when sliding downward it moves the gripper segments (21) outward.

Part nr. 23) Release spring lower gripper. The spring load of this spring pushes the gripper segments (21) inward by pushing the inner body (22) upward relative to the drill pipe (1) and it prevents sliding of gripper segments (21) against the liner during a reset stroke.

Part nr. 24) Inner body release spring. This inner body limits the displacement of the inner body (22) and thereby the reach of the lower gripper and it centralizes the release spring.

Part nr. 25) Fixed segment retainer ring lower gripper system constrains the gripper segments (21) . Part nr. 26) Gripper piston. This piston activate the lower gripper system by displacing the inner body (22) when hydraulic pressure is applied.

Part nr. 27) Bottom plug cement seal. This seal shoulder against the liner bottom and prevent u-tubing of cement, it also acts as a guide nose while running in hole .

Part nr. 28) Wiper dart. This dart lands in a dart seat and closes off the drill pipe. This enables pressure build and thereby hydraulic expansion.

Part nr. 29) Open Hole Anchors known from US patent

8522866 and US patent applications US20120175105;

US20120152526 and US20120160480. Theses anchors bite into the formation when expanded and secure the liner in place enabling expansion by rig pull.

Operational description of the upper part of the

MALTEM tool, also referred to as the ALTEM tool.

The ALTEM tool is run with active upper grippers (3), retracted lower grippers (21), a starter joint (14), open hole anchors (29) and cement seal (27) . The starter joint (14) carries the buoyant liner weight

(A) . At TD cement is pumped via the drill pipe (1) through the jacking system and cement seal (27) (B) . A wiper dart (28) is pumped behind the cement, which lands below the jack in a dart catcher sub and seals off the drill pipe communication with the well bore

(B) . This enables pressure build up inside the cylinder of the jack (17) . The piston pushes (13) against the expansion cone (12) when pressure is applied (C) . This piston (13) can freely slide over the inner rod (1) . The cylinder side (17) is fixed relative to the inner rod (1) . Liner movement in upward direction is

prevented by the upper gripper segments (3), which bite into the liner. The liner is expanded in compression when the cone is pushed upward by the jack piston (13) (C) . When pressure is released the pressure chamber is closed by the buoyant liner weight (D) . This reset stroke lowers the expanded liner over the lower grippers (21) onto the shoulder of the cement seal (27) (E) . Liner weight will shear the dart catcher sub (28) loose from the cement seal (27) . This cement seal (27) closes off the liner bottom and will prevent further u- tubing of cement. Communication between the annulus above and below the cone is established via circulation ports through the expansion cone (12) . Switching over from expansion in compression to expansion in tension is realized by an increase in pressure at the end of a stroke (F) . This pressure peak will deactivate the upper gripper (3) and activate the lower gripper (21) by shearing loose a gripper piston (26) that pushes against the lower gripper (22) . Releasing pressure enables another reset stroke of the jack. Subsequently when pressure is applied the lower grippers (22) are activated and the cone (12) is pushed in upward direction. Upward liner movement is now prevented by the lower grippers (22) . The liner is now expanded in tension and is pulled over the cone (12) . After expanding through and activating of the open hole anchor (29) it is possible to continue expansion in tension by rig pull only (G) . Resetting the jack can now also be realized by pulling up the drill string. If the cone would be pulled into the overlap by means of rig pull than allot of tension is frozen into the liner between the overlap section and open hole anchor (29) . Before entering the overlap liner-tension can be reduced and the jack can be used to continue expansion. This enables a reduction in installation load compared to other expandable systems, which rely on rig pull or hydraulic expansion only. The ALTEM system enables a liner installation in compression or (less) tension. This favors collapse resistance of the expanded liners. At the liner top the cone (12) can be pushed out with the hydraulic jack and lower grippers (22), which eliminates cone pop out issues (H) .

Detailed description of the upper part of the MALTEM tool, which is also identified as the ALTEM tool .

The upper gripper (3) (AA) is initially engaged with the expandable liner. Pressure is applied via the string (1) through flow ports (18) into the hydraulic jack. This pressure pushes the jack piston (13) against the expansion cone (12) and pushes the expandable liner upward. This motion is stopped by the upper gripper and energizes the upper gripper segments (3) via the fixed inner body (2) of the upper gripper. Further pressure increase would push the expansion cone (12) into the expandable liner. At the end of each stroke the pressure increases, because the cone (12) shoulders against the gripper release sub, which is initially fixed to the string (1) . This gripper release sub consists out of an outer (9) and inner body (8) . The inner body (8) is fixed relative to the string (1) . The outer body (9) is fixed to the inner body (8) via shear bolts (10) . The activation spring (6) continuously energizes the gripper segments (3) via the retainer mandrel (7), which keeps the segments together. This activation spring also compresses the release spring (5) . Long thick pins (4) constrain the gripper segments (3) to the fixed inner body (2) but do enable a sliding motion. This upper gripper can be released when it is desired to switch over from expansion in compression to expansion in tension. In this case the lower gripper should be inside the expandable liner, which is achieved after the second stroke. At the end of a stroke pressure can be increased. This pressure increases the load on the shear bolts (10) via the jack piston (13), expansion cone (12), near cone stabilizer (11) and outer body of the gripper release sub (9) . When the shear pressure is applied the outer body (9) of the gripper release sub moves upward. Subsequently the outer body (9) can slide downward over the inner body (8) and releases the activation spring load (6) on the gripper segments (3) . The gripper release spring (5) keeps the gripper segments (3) retracted. This eliminates the risk of scraping away coating with the segment teeth and it makes the system retrievable when expanding top-down. It also enables to run back in to TD during well control situations. However the cone (12) could be jammed inside the expanded liner.

Exerting a load on top of the cone (12) would in this case energize the upper gripper again. This can be mitigated by engineering a self-locking mechanism inside the gripper release sub, which locks the outer body (9) in released position. When running in hole the liner starter-joint (14) shoulders on the expansion cone (12) . This expansion cone (12) shoulders against the cone nut (15), which is fixed relative to the string (1) . Flow ports inside this cone nut (15) enables fluid flow between the different annuli and mitigates trapped pressures. Check valves (16) inside the jack piston (13) stops u-tubing of cement and enables fluid flow when expanding by rig pull. A recess groove over the cone nut (15) ensures communication with the check valves (16) at all times. Cement can start u-tubing when the ALTEM tool is operated. Cement can then flow via ports into the jack piston (13), through the expansion cone (12) and near cone stabilizer (11) into the liner annulus above. This flow can be mitigated by placing check valves inside the expansion cone (12) but this would restrict the fluid flow during jacking operations risking swabbing pressures. Best option is to fill the annuli inside the tool and liner with a viscous weighted fluid that counter balances the initial hydrostatic pressure of the cement until the cement seal is pulled inside the expanded liner. Alternatively a swab cup can be placed above the upper gripper (3) . A swab cup would, similar to check valves inside the cone, also restrict the fluid flow in one direction and might cause swabbing pressures during a straight pull. Final option is to pull up the liner bottom across the top of cement after it is pumped, expand the first liner section and set the cement seal. Subsequently run back in into the cement with a closed liner bottom. When the upper gripper (3) is disengaged the pressure can further be increased to activate the lower gripper (22) . Jack piston (13) will shoulder against the cone nut (15) during this step. This pressure will be exerted via flow ports through the jack cylinder (17) on the gripper piston (26), which is kept in place by shear bolts (19) . These shear bolts (19) shear at a higher pressure than the maximum anticipated pressure during expansion in compression. This releases the gripper piston (26), shifts the inner body (22) against the spring load (23) until the gripper segments (21) are engaged with the expanded liner or until the inner body (22) shoulders against an end stop (24) . A retaining ring (25) keeps the gripper segments (21) together. Long thick pins (20) constrain the gripper segments (21) relative to the inner body (22) and enable a sliding motion. When pressure is released the gripper spring (23) disengages the gripper segments (21) from the expanded liner by pushing the gripper piston back (26) via the inner body (22) . This makes the system retrievable in a top-down expansion situation and in a bottoms-up expansion system it enables to run back in hole during well control events. In this case the dart should have a rupture disc to allow communication with the well bore again and to enable the reading of shut in drill pipe pressures. The gripping range of the lower gripper (21) is less critical compared to the upper gripper (3), because the ID of the expanded liner is well defined and is almost equal to expansion cone (12) diameter. However these gripper segments (21) must be exchanged when changing the expansion cone (12) size.

Therefore, the method, system and/or any products according to present invention are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein.

The particular embodiments disclosed above are illustrative only, as the present invention may be modified, combined and/or practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein.

Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below.

It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined and/or modified and all such

variations are considered within the scope of the present invention as defined in the accompanying claims . While any methods, systems and/or products embodying the invention are described in terms of "comprising," "containing," or "including" various described features and/or steps, they can also "consist essentially of" or "consist of" the various described features and steps.

All numbers and ranges disclosed above may vary by some amount . Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, "from about a to about b," or, equivalently, "from approximately a to b," or,

equivalently, "from approximately a-b") disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values .

Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee.

Moreover, the indefinite articles "a" or "an", as used in the claims, are defined herein to mean one or more than one of the element that it introduces .

If there is any conflict in the usages of a word or term in this specification and one or more patent or other documents that may be cited herein by reference, the definitions that are consistent with this

specification should be adopted.

Claims

CLAIMS :

1. A method for downhole expansion of a well

tubular (100) , the method comprising:

- providing an expansion tool comprising a carrier body (101) which carries a first expansion

cone (12), a second expansion cone (112) having a larger outer width than the first expansion cone (12) and a first, second and third expandable gripper ( 3 , 22A, 22B ) , which are slidably mounted on the carrier body (101) above, between and below the expansion cones (12, 112 ) ;

- suspending the expansion tool from a drill string in a well at one end of the well

tubular (100) ;

- activating drilling fluid actuated piston (13, 26) and cylinder assemblies to induce the

grippers (3, 22A, 22B) to sequentially slide relative to the carrier body (101) in a caterpillar mode, thereby :

- alternatingly pulling and pushing the expansion cones (12, 112 ) through the tubular (100 ) ; and

- inducing the first expansion cone (12) to expand at least a substantial part of the tubular (100) initially to a first expanded width and inducing the second expansion cone (112) to expand at least a minor part of the tubular (100) to a larger width than the first expanded width.

2. The method of claim 1, wherein the first and

second expansion cones (12, 112) are both moved through substantially the entire length of the tubular (100) , thereby expanding the entire tubular to the larger width generated by the second expansion cone. The method of claim 1 or 2, wherein the expansion tool is induced to move in upward direction from a lower end to an upper end of the tubular (100) . The method of claim 1 or 2, wherein the expansion tool is induced to move in downward direction from an upper end to a lower end of the tubular (100) . An expansion tool for downhole expansion of a well tubular (100) , comprising

- a carrier body (101) which carries a first expansion cone (12), a second expansion cone (112) having a larger outer width than the first expansion cone (12) and a first, second and third expandable gripper (2, 22A, 22B) , which are slidably mounted on the carrier body (101) above, between and below the expansion cones (12, 112) ;

- a connector for connecting the expansion tool to a drill string in a well at one end of the well tubular (100) ;

- drilling fluid actuated piston (13,26) and cylinder assemblies for inducing the

grippers (2, 22A, 22B) to sequentially slide relative to the carrier body (101) in a caterpillar mode, thereby, when in use: