Improvements in or relating to the abandonment of wells

Description

1 / 19 Improvements in or relating to the abandonment of field wells

[001] The present invention relates to methods and apparatus for abandoning wells and, in particular, though not exclusively, to a method and apparatus for removing a section of tubing along a longitudinal section of the well in order to allow the placement of a cement plug. FUNDAMENTALS

[002] When a well reaches the end of its commercial life, it is abandoned in accordance with strict regulations in order to prevent fluids from permanently escaping from the well. To comply with regulations, it has become good practice to create a cement plug along a predetermined length of the well. As a well is constructed by placing conduits such as casing, liner, pipes and tubing (hereinafter collectively referred to as tubulars) in the well, the cement plug must extend through all rings present in the well. In many cases, all internal conduits are removed, leaving the outer casing, including the ring bounded by the formation.

[003] The integrity of the casing and, in particular, the cement in a ring will determine whether a cement plug can be located just in the tubular. Steel casing can leak at the connections or corrode due to acids. Cement can also deteriorate over time, but leaks also occur when cement shrinks, develops cracks or channels, or is lost into the surrounding rock when applied. If integrity fails, gases and liquids can leak out of the casing or, equally importantly, move into, up, and out of the well through the defective cement between the casing and the rock wall. These issues affect the ability to plug a well for abandonment, but also to ensure zonal isolation in unconventional reservoirs. Cement bond strength (CBL) measurement can be used to measure bond quality. Petition 870250095013, dated 10 / 17 / 2025, p. 13 / 39 2 / 19 of the cement, but if the CBL shows that the bond is weak, intervention with access to the outermost pipe is necessary.

[004] One method for creating or repairing cement plugs is to mill the inner tubular to expose the ring behind the tubular and then pump cement into the enlarged area to create the cement plug. This is done using a rotary section milling machine operated on a work column and typically operated downwards to remove the tubular section. When milling downwards, the weight of the work column is used to apply downward force to the section milling machine, causing it to advance through the tubular being milled. This application of force to the milling machine by the weight applied from above creates an oscillation in the milling work column, which tends to fracture the cutting inserts on the blades of the section milling machine. This, in turn, causes the milling machine to wear out more quickly, resulting in fewer meters of tubular being removed before milling machine replacement is required.Furthermore, as milling progresses downward, debris must be removed from the wellbore as it forms to prevent a ball of debris from forming around the milling machine and reducing its effectiveness. A specialized milling fluid formulation and maintenance of proper fluid flow rates are necessary to circulate the debris out of the hole.

[005] To overcome these disadvantages, an alternative method was developed that drills the tubular and pumps cement through the perforations to rise through the ring and thus create a plug within the ring. This drilling and plugging arrangement, sometimes called cement injection, has disadvantages in that, by forcing cement through narrow openings, there is no guarantee that the cement will come into full contact with the surrounding formation, since the cement may not reach all areas of the ring. As a result, the cement plug may be compromised and become at least partially ineffective. Petition 870250095013, dated 10 / 17 / 2025, p. 14 / 39 3 / 19 This method offers a significant advantage because it can be performed from a floating or semi-submersible vessel, providing what is known as the platform-less abandonment method. By eliminating the need for a drilling rig, it is possible to save time and, consequently, significant costs in the well abandonment procedure. In the platform-less method, the work string is anchored to the tubular and, as such, sea waves will exert tension and / or weight on the work string. Even with the use of wave compensators, this variable load means that a section milling machine, which relies on the use of controlled weight to operate, cannot be used.

[006] GB2565804 describes a section milling machine and method for removing a section of tubular material from a well. The section milling machine includes elongated blades that have a cutting structure extending along at least a portion of the length from a first edge and at least a portion of the width from a second edge of the elongated cutting blade, the second edge being longer than the first edge, and the first and second edges being perpendicular to each other. The blades are moved axially and radially relative to the tubular body to position the second edge parallel to the central longitudinal geometric axis for milling. The milling machine is operated in an upward direction, using a hydraulic tensioning device to provide a constant load, so that the tubular milling can be performed in a platformless device.A suitable hydraulic tensioning device is described in GB2567157, which maintains a constant load on the section milling machine, so that long sections of pipe can be removed in a near-continuous procedure in a single trip into the well, in a platformless well abandonment procedure. Petition 870250095013, dated 10 / 17 / 2025, page 15 / 39 4 / 19

[007] One difficulty in tubular milling in a platform-less procedure is in repositioning the section milling machine in the milled window when the tool string is retrieved to change blades or perform other operations on the string. It is difficult to locate the section milling machine back in the window when the downhole assembly is deployed on coiled pipes or small-diameter drill pipes due to the elongation or compression experienced in the running string. SUMMARY

[008] Aspects of the present disclosure relate to methods and apparatus for abandoning wells and, in particular, though not exclusively, to a method and apparatus for removing a section of tubing along a longitudinal section of the well to allow the placement of a cement plug.

[009] According to a first aspect, a method is provided for removing a section of well piping, comprising the steps of: (a) locate a bridge plug in the well piping; (b) provide a first column with a first downhole assembly comprising a cutting tool and a rotating sub; (c) introduce the first string into the well tubing and lay the first wellhead assembly on the bridge plug; (d) cut the well tubing with the first wellhead assembly resting on the bridge plug, in order to provide a depth reference; (e) introduce a second column and lay a second wellbore assembly comprising a pipe removal tool in the bridge plug to obtain the depth reference; (f) position the pipe removal tool in the well pipe relative to the depth reference; and Petition 870250095013, dated 10 / 17 / 2025, page 16 / 39 5 / 19 (g) Use the pipe removal tool to remove a section of well pipe. [01 0] In this way, when placing a wellbore assembly on the bridge plug when more columns are introduced into the tubing, a depth reference is provided in the well to return to the location of the cut. Thus, when a window is cut in the tubing, its position is known and subsequent introductions into the tubing can locate it for the purpose of milling the tubing. [01 1] Advantageously, the method avoids or mitigates at least some of the disadvantages of the state of the art. Alternatively or additionally, the method provides a method of removing a section of well tubing that provides depth control. [01 2] Step (d) can be performed by the cutting tool being operated by rotation by a motor and rotating the cutting tool in the sub-rotator. The motor can be on the surface and the rotation of the cutting tool is done by the rotation of the first column. The motor can be in the first downhole assembly. [01 3] The cutting tool may be located between the motor and the rotary sub. More particularly, the rotary sub may be at one end of the first wellbore assembly and may be placed on the buffer. [01 4] The cutting tool may comprise one or more blades for cutting the well tubing on the first contact of one or more blades with the tubing. [01 5] The pipe removal tool can be a milling tool. In this way, a section milling machine can be used to remove the well pipe section by milling. [01 6] The first wellhead assembly may further comprise a pipe removal tool for opening a window in the well pipe, since the tool of Petition 870250095013, dated 10 / 17 / 2025, page 17 / 39 6 / 19 cut has cut the well tubing. The method may include creating a window in the well tubing in step (d).

[017] Step (g) can be performed by the pipe removal tool being operated by rotation by a motor. The motor can be on the surface and the rotation of the pipe removal tool is done by rotation of the second column.

[018] Step (g) can be performed by raising the second column so that milling is performed in an upward direction. More particularly, the second downhole assembly may include a hydraulic tensioning device to maintain a constant load on the pipe removal tool as it is raised.

[019] In one embodiment, the cutting tool and the pipe removal tool are combined, in that one or more blades include a cutting edge and a milling surface. In this way, the first downhole assembly can open a window in the well casing. More particularly, by combining the cutting tool and the pipe removal tool, the second downhole assembly and the first downhole assembly can be identical. This allows only the replacement of one or more blades between the introduction of the first and second casings.

[020] The bridge plug may be located in the first downhole assembly and step (a) may be performed after step (b) in the same introduction into the wellbore. This reduces the number of trips into the well. The second downhole assembly may also comprise a swivel. In this way, when the second string is laid, no damage can occur if the string is being swiveled.

[021] Well tubing can typically be casing or production tubing. Well tubing has a diameter of 178 mm (7”) or less. In one embodiment, well tubing has a diameter of 114 mm (4.5”). The first column and the second Petition 870250095013, dated 10 / 17 / 2025, page 18 / 39 7 / 19 column can be coiled tubing or drill pipe. The drill pipe will have a small diameter to be inserted into the wellbore tubing.

[022] The method may include the step of creating a cement plug over the milled section of the well tubing.

[023] According to a second aspect, an apparatus is provided for removing a section of well piping, comprising: a tubular column that supports a wellhead assembly suspended from it; the well bottom assembly comprising, in order from the column: a combined pipe cutting and removal tool; and a rotary tool, in which: The rotary mechanism is configured to allow rotation of the combined pipe cutting and removal tool when the string is placed over a plug in the well pipe.

[024] In this way, as the combined pipe cutting and removal tool can rotate relative to a lower end of the rotating sub, the column can be placed under compression to make a cut.

[025] Advantageously, the device avoids or mitigates at least some of the disadvantages of the prior art. Alternatively or additionally, the device avoids or mitigates at least some of the disadvantages of the prior art. Alternatively or additionally, the device provides a device for removing a section of well tubing that provides depth control.

[026] The combined pipe cutting and removal tool may comprise a plurality of blades, each blade having a cutting edge to form a circumferential cut in the well pipe and a milling surface to mill the well pipe when rotated. This provides the functions Petition 870250095013, dated 10 / 17 / 2025, page 19 / 39 8 / 19 double cutting and milling blades in a single tool. The blades can be moved between a retracted configuration, where they are inside the tool body, and an extended configuration, where they extend radially out of the body for use.

[027] The downhole assembly may comprise a tensioning device, the tensioning device configured to apply a constant load to the combined pipe cutting and stripping tool when the blades are in the extended configuration.

[028] The downhole assembly may comprise a motor. In this way, the combined pipe cutting and stripping tool may be rotated in the downhole assembly independently of the spindle rotation. The combined pipe cutting and stripping tool will rotate between the motor and the spindle. The motor may be a left-hand positive displacement motor. This prevents potential unwinding of the pipe during rotation.

[029] The tubular string may be coiled tubing. Alternatively, the tubular string may be drill pipe. More particularly, the tubular string may have a diameter of less than 178 mm (7”). In one embodiment, the tubular string may have a diameter of less than 114 mm (4.5”).

[030] In the description that follows, the drawings are not necessarily to scale. Certain features may be shown exaggerated in scale or in a somewhat schematic way, and some details of conventional elements may not be shown for the sake of clarity and conciseness. It should be fully recognized that the different teachings of the modalities discussed below may be employed separately or in any suitable combination to produce the desired results. Consequently, the drawings and descriptions should be considered illustrative in nature and not restrictive. Furthermore, the terminology and phraseology used Petition 870250095013, dated 10 / 17 / 2025, page 20 / 39 9 / 19 in this document are used solely for descriptive purposes and should not be construed as limiting their scope. Terms such as including, comprising, having, containing or involving and their variations are intended to be broad and encompass the subject matter listed below, equivalents and additional matters not mentioned, and are not intended to exclude other additives, components, wholes or steps. Similarly, the term comprising is considered synonymous with the terms including or containing for applicable legal purposes.

[031] All numerical values ​​in this disclosure are understood to be approximated. All singular forms of elements or any other components described in this document, including (without limitation) apparatus components, are understood to include their plural forms.

[032] The invention is defined by the appended claims. However, for the purposes of this disclosure, it should be understood that any of the features defined above or described below may be used alone or in combination. For example, the features described above in relation to one of the aspects above or below in relation to the detailed description may be used in any other aspect or, together, form a new aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[033] Several embodiments of the invention will now be described, by way of example only, with reference to the drawings, of which: Figures 1 (a) and 1 (b) are schematic illustrations of the first steps of a method for removing a section of well pipe, according to an embodiment of the present invention; Figures 2(a), 2b and 2(c) are schematic illustrations of additional steps in a method for removing a section of well piping, according to an embodiment of the present invention; and Petition 870250095013, dated 10 / 17 / 2025, page 21 / 39 10 / 19 Figures 3(a), 3(b) and 3(c) are schematic illustrations of additional steps in a method for removing a section of well piping, according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE DRAWINGS

[034] With reference initially to Figure 1(a) of the drawings, a well pipe, generally indicated by the reference numeral 10, located in a well 12 in which a section 20 of the well pipe 10 is to be removed, according to an embodiment of the present invention, is illustrated. The well pipe 10 is typically a liner or production pipe with a diameter of 178 mm (7”) or less, with a diameter of 114 mm (4.5”) for this embodiment. In this example, the well pipe 10 is located within an external pipe 14, such as a liner or casing. It is important to note that an external pipe 14 is not required and that the well pipe 10 can be the only pipe and can be cemented in place. Inside well pipe 10, at a location below section 20 to be removed, there is a plug 30. Plug 30 is a bridge plug, as it is known in the art, and provides a seal across the bore of well pipe 10.

[035] A first tubing string 16 is introduced into the well tubing 10. The first tubing string 16 is formed from coiled tubing or small-diameter drill pipe. The first tubing string 16 can be introduced from a floating vessel to perform platform-free intervention for a subsea well 12. The method finds equal application for land-based wells and wells serviced by a platform. The first tubing string 16 supports a first downhole assembly 18. Located on the first downhole assembly 18 are a cutting tool 22 and a sub swivel 24. The sub swivel 24, sometimes referred to as a downhole swivel joint, is known in the art for allowing Petition 870250095013, dated 10 / 17 / 2025, page 22 / 39 11 / 19 that one end of the sub 2 4 rotates relative to a second end that is held static. The cutting tool 22 can be any cutting tool 22 that operates by means of cutting blades 2 6 extending from the tool body 28, with cutting edges 32 on the blades 26 in contact with the inner surface 34 of the well pipe 10 to provide a circumferential cut 36 through the well pipe 10 when the cutting tool 22 is rotated.

[036] In the method, the first tubing string 16 is introduced into the well 12 until the swivel sub 24, located at the distal end 38 of the first downhole assembly 18, rests on the plug 30. Upon resting on the plug 30, weight is placed on the first tubing string 16. This effectively compresses the coiled tubing or drill pipe of the first tubing string 16 to remove any elongation caused by the weight of the first downhole assembly 18 when introduced. The end of the swivel 24 on the plug 30 will be held static by the weight of the first downhole assembly 18 and the first tubing string 16.

[037] Cutting tool 22 is then operated to extend cutting blades 26 and create a cut 36 through well tubing 10. To create the cut 36, cutting tool 22 is rotated either by rotating the first tubing string 16 from the surface or by using a motor 40 located above cutting tool 22 in the first downhole assembly 18. In the illustrated method and apparatus, motor 40 is a fluid-driven left-hand positive displacement motor. The rotator 24 facilitates the rotation of cutting tool 22 while remaining in the weight assembly or landing configuration. The cut 36 provides a depth reference 42 in well tubing 10 by virtue of the distance defined between the plug 30 and the cut 36, which corresponds to the distance between cutting blades 26 and the end 38 of the first downhole assembly. Petition 870250095013, dated 10 / 17 / 2025, page 23 / 39 12 / 19 bottom of well 18. Consequently, any rope inserted into well tubing 10 and placed on plug 30 will be able to determine the position of depth reference 42 and find cut 36.

[038] In the embodiment shown, the cutting tool 22 is combined with a milling tool to provide a double-acting section milling machine 44. The section milling machine 44 is described in GB2565804 and is incorporated herein by reference. The section milling machine has a tubular body and includes elongated blades 26 having a cutting structure 48 extending along at least a portion of a length from a first edge 50 and at least a portion of a width from a second edge 52 of the elongated cutting blade 26. The blades 26 are moved by an actuator axially and radially relative to the tubular body between a first retracted position and a second extended position, in each of which the second edge of the blade is parallel to a longitudinal geometric axis of the device.The tubular body may have a cam body profile on an inner surface that engages with a profile on the cutting blade 26 to provide radial movement when the cutting blade 26 is moved axially by, for example, a piston. The body profile has a ramp to cause tilting of the cutting blade 26 in a third blade position, so that the blade apex 54 provides the cutting edge 32.

[039] When first activated, by fluid flow through the hole of the first tube column 16, the retracted blades 26 are tilted to the third blade position, so as to provide the cutting edge 32. This is shown in Figure 1(a) and provides the depth reference 42, as described previously. Continuous pumping of fluid will cause the blades 26 to extend fully, with the second edge 52 parallel to the longitudinal geometric axis of the milling machine 44 and the Petition 870250095013, dated 10 / 17 / 2025, page 24 / 39 13 / 19 first pipe column 16. The cutting structure 48 on the blades 26 provides a milling action to mill the well pipe 10 and create a window 46. This is shown in Figure 1(b).

[040] At this stage, the first pipe string 16 can be removed if it is necessary to use a dedicated milling tool 56 to mill and remove section 20 of the well pipe 10. If this is the case, then a second string 58 is introduced into the well 12 and placed on the bridge plug 30. The second downhole assembly 60 in the second string 58 includes the milling tool 56. The milling tool 56 is shown in combination with a hydraulic tensioning device, being an upward thrust tool 62, an anti-torque tool 64, a motor 40 and the rotating sub 24 in the second downhole assembly 60 in Figure 2(a).When placed on the plug 30, the distance to the second wellbore assembly 60, from the distal end 66 on the plug 30 to the blades 68 on the milling tool 56, is spaced to correspond to the depth reference 42, so that when the blades 68 on the milling tool 56 open, normally at a pivot, they will be within the window 46 at a known distance from the depth reference 42. In this way, the depth reference 42 ensures that the cut 36 and the position of the window 46 can be found on repeated entries into the well 10.

[041] The milling tool 56 is now positioned at the lower end of the span where a section 20 of the wellbore 10 is to be cut. Typically, the components of the second downhole assembly 60 are arranged with the milling tool 56 above the rotary 24 at the bottom, with a stabilizer 70, the uplift thruster 62, the mud motor 40 and an anti-torque anchor 64 positioned above, in that order. Petition 870250095013, dated 10 / 17 / 2025, page 25 / 39 14 / 19

[042] The upward thruster 62 may be as disclosed in US 6,679,329 and may be regarded as a hydraulic tensioning device. US 6,679,329 is incorporated herein by reference. The purpose of the device 62 is to provide a constant upward load on the milling tool 56 so that upward milling is performed. If a mud motor 40 were used to drive the milling machine 56 without the device 62, the load transmitted by the work string operated from a floating vessel to lift the milling machine 56 and cut the well pipe 10 would be too uneven. The operator would have to be very careful not to overload the milling machine 56, otherwise the mud motor 40 would stall. Device 62 is a hydraulic cylinder pressurized by the flow of mud that is pumped through a fluid flow path in the anti-torque anchor 64, in the mud motor 40, in device 62 and down through the milling tool 56.Drilling mud passes through the milling tool 56 below the ascending thruster 62 to operate the milling machine 56. When the milling machine needs to be moved upwards, a flow restriction creates back pressure in the second downhole assembly 60. This back pressure is used to cause the device 62 to rise upwards in the milling tool 56. With a tensioning device 62 in the assembly 60, the pump pressure can be controlled so that the load on the milling machine 56 is very constant and the load can be transmitted with much greater precision.

[043] In use, the anti-torque anchor 64 is adjusted against the inner surface 34 of the wellbore pipe 10 as the milling fluid pressure is increased, which also starts the mud motor 40 and exerts an upward force on the milling tool 56 with the device 62. Rotation of the second downhole assembly 60 is facilitated in the landing position by rotation on the rotary 24. Fluid pressure operates Petition 870250095013, dated 10 / 17 / 2025, page 26 / 39 15 / 19 The blades 68 and the milling tool 56 are rotated by the downhole motor 40. The torque anchor 64, the mud motor 40, the tensioning device 62, the stabilizer 70, and the milling tool 56 can have the sizes and shapes of their fluid flow paths designed to initiate their respective operations at selected progressive pressure levels, to ensure the desired activation sequence of the various tools. Additionally, the motor 40 can be designed to divert the fluid before it starts rotating. As a result, the blades 58 extend, then the torque of the anchor blades 64 comes into contact with the wellbore 10, then the mud motor 40 starts rotating, and finally, the device 62 starts lifting the milling tool 56. The blades 68 will mill the lower end 72 as the device 62 moves the section milling tool 10 upward.Milling will continue until device 62 reaches its full stroke, or “bottoms out.” A pressure drop will be observed in the milling fluid at this point. Device 62 must then be repositioned to continue milling section 20.

[044] An alternative upward thruster 62 that does not suffer from bottoming out is the automatic load control sub disclosed in GB2568593, which is incorporated herein by reference. This hydraulic tensioning device 62 provides continuous upward milling of the pipe by raising the work column at a desired progress rate. The automatic load control sub 62 has a lower end that is longitudinally movable relative to the application of fluid pressure on the work column to apply weight to the milling tool 56. The automatic load control sub 62 includes a self-correcting mechanism to maintain the lower end in a position between a fully extended position and a fully retracted position to provide continuous milling of the pipe by the milling tool 56. Petition 870250095013, dated 10 / 17 / 2025, page 27 / 39 16 / 19 is a milling speed that corresponds to the speed at which the second column 58 is raised.

[045] In alternative embodiments, the second column 18 is rotated to operate the milling machine, and the anti-torque anchor 64 and the mud motor 40 are not used.

[046] Due to the narrow depth of the 68 blades, these will likely need to be replaced several times to mill the entire section 20 of the wellbore 10. For this, the 68 blades are retracted and the second string 58 is pulled out of the well. The 68 blades are replaced and the second string 58 can be introduced into the well 10. The second wellbore assembly 60 is placed over the plug 30 and the milling blades 68 will be located at depth reference 42. From this reference point, the second string 58 can be raised by an amount equal to the previously milled section of wellbore 10, as shown in Figure 2(b). This distance is known from the length of the upward thruster stroke 62 and the number of times it was restarted in the previous run or from the distance traveled by the second string 58 as milling occurred.

[047] Alternatively, at the surface, when the 68 milling blades are replaced, the length of the second downhole assembly 60 can be extended by the calculated distance. In this way, when the second downhole assembly 58 lands on the plug 30, the milling blades 68 will be located in the last milling position, as shown in Figure 2(c). In either embodiment, the depth reference 42 allows the window 46 to be located for additional operations and well entries 10. This also offers the opportunity to change the milling blades when centralizers and collars are reached or to avoid centralizers and collars by stopping and starting milling on either side of the centralizers and collars. Petition 870250095013, dated 10 / 17 / 2025, pp. 28 / 39 17 / 19

[048] The process can be repeated until the desired section 20 of well pipe 10 is removed from well 12.

[049] If the double-acting section milling machine 44 is used, then once the window 46 is formed and the blades 26 are in the longitudinal position, the first column 16 can be lifted while the milling machine 44 is rotated to remove the wellbore tubing 10 above the cut 36. To facilitate this, the first downhole assembly 18 would include the torque anchor 64, the mud motor 40, the tensioning device 62 and the stabilizer 70. This is shown in Figure 3(a). As the cutting surface of the blades 26 is longer than the narrow blades 68 on the milling tool 56, longer lengths of wellbore tubing 10 can be milled before the first column 16 has to be removed for blade replacement 26. This is more easily facilitated by using the automatic load control sub as the tensioning device 62.Once blades 26 have been replaced, the same string can be used as a second string 18 and placed over the plug 30 to obtain the depth reference 42, see Figure 3(b), before moving to the last milled position, as described earlier in this document. Milling on a longer section can begin again to complete the removal of section 20 from well tubing 10. This double-action section milling machine 44 therefore reduces the number of trips required to remove a section 20 from well tubing 10. The double-action section milling machine 44 also allows milling to be interrupted when a connector or centralizer is encountered, blade 26 is retracted, string 16,18 is moved to position the section milling machine 44 above the connector or centralizer, and the apex of blade 54 initially used to make a new cut, so that milling can continue without needing to remove string 16,18 from well 12. Petition 870250095013, dated 10 / 17 / 2025, pp. 29 / 39 18 / 19

[050] In another embodiment, the first column 16 may include the plug 30 in the first well bottom assembly 18. The entry would then place the plug 30, separating it from the first column 16, and then place weight on it. This would further reduce the number of trips to well 12.

[051] In yet another embodiment, once the section of well tubing has been removed, a cement plug 08 can be created in the well tubing over the removed section of well tubing, as is known in the art. This is illustrated in Figure 3(b).

[052] A particular advantage of one or more embodiments of the present invention is that it provides a method for removing a section of well tubing, in which a depth reference is provided for repositioning the location when an additional string is placed in the well.

[053] An additional advantage of one or more embodiments of the present invention is that it provides a method of removing a section of well tubing that overcomes the difficulties in calculating depths to locate the window due to elongation or compression in the tubing string, particularly in coiled tubing operations.

[054] The preceding description of the invention is presented for illustrative and descriptive purposes only and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The embodiments described have been chosen and described in order to better explain the principles of the invention and its practical application, thus enabling other skilled individuals to make the best use of the invention in various embodiments and with various modifications suitable for the specific intended use. Therefore, other modifications or improvements may be incorporated without departing from the scope of the invention intended in this document. For example, although the section milling machine is described for upward movement for milling tubular material, the section milling machine could also be adapted to operate in a downward manner. Petition 870250095013, dated 10 / 17 / 2025, pp. 30-39 19 / 19 Additionally, ropes that include other tools can be used in the well to perform additional tasks, for example, locating a boom in a cut section of the casing to pull the casing. This cutting and pulling can be attempted to verify if the well tubing can be removed without the need for milling the section. Petition 870250095013, dated 10 / 17 / 2025, pp. 31 / 39

Claims

1 / 4 CLAIMS 1. Method for removing a section of well tubing, characterized in that it comprises the steps: (a) locating a bridge plug in the well tubing; (b) providing a first string with a first downhole assembly comprising a cutting tool and a rotating sub; (c) introducing the first string into the well tubing and landing the first downhole assembly on the bridge plug; (d) cutting the well tubing with the first downhole assembly landed on the bridge plug to provide a depth reference; (e) introducing a second string and landing a second downhole assembly including a tubing removal tool on the bridge plug to obtain the depth reference; (f) positioning the tubing removal tool in the well tubing relative to the depth reference; and (g) using the tubing removal tool to remove a section of the well tubing.

2. Method according to claim 1, characterized in that step (d) is performed by the cutting tool being operated by means of rotation by a motor and rotating the cutting tool in the sub-rotating mechanism.

3. Method according to claim 2, characterized in that the motor is in the first well bottom assembly.

4. A method, according to any of the preceding claims, characterized in that the rotating submersible is at one end of the first wellbore assembly and is placed on the plug.

5. Method, according to any of the preceding claims, characterized in that the cutting tool Petition 870250095013, of 10 / 17 / 2025, page 32 / 39 2 / 4 comprises one or more blades for cutting well tubing at the first contact of one or more blades with the tubing.

6. A method, according to any of the preceding claims, characterized in that the pipe removal tool is a milling tool and the well pipe section is removed by milling.

7. Method, according to any of the preceding claims, characterized in that the first wellbore assembly further comprises a pipe removal tool for opening a window in the wellbore once the cutting tool has cut the wellbore and the method includes creating a window in the wellbore in step (d).

8. Method, according to any of the preceding claims, characterized in that step (g) is performed by the pipe removal tool being operated by rotation by a motor.

9. Method, according to any of the preceding claims, characterized in that step (g) is performed by raising the second column so that milling is performed in an upward direction.

10. Method according to claim 9, characterized in that the second wellbore assembly comprises a hydraulic tensioning device and maintains a constant load on the pipe removal tool as it is lifted.

11. A method, according to any of the preceding claims, characterized in that the cutting tool and the pipe removal tool are combined and the first wellbore assembly opens a window in the well pipe.

12. Method, according to claim 11, characterized in that the second set of well bottom and the first set of well bottom are identical.

13. Method, according to any one of claims 1 to 11, characterized in that the bridge plug is located in the first wellbore assembly and step (a) is performed after step (b) in the same run in the wellbore tubing.

14. A method, according to any of the preceding claims, characterized in that the second wellbore assembly comprises a swivel so that the second column can rotate when it lands on the plug.

15. Method, according to any of the preceding claims, characterized in that the well pipe has a diameter of 178 mm (7") or less.

16. Method according to claim 15, characterized in that the well pipe has a diameter of 114 mm (4.5 in).

17. A method, according to any of the preceding claims, characterized in that it includes the step of creating a cement plug over the milled section of the well tubing.

18. Apparatus for removing a section of well tubing, characterized in that it comprises: a tubular column supporting a wellbore assembly suspended therefrom; the wellbore assembly comprising, in order from one end of the column: a combined cutting and pipe removal tool; and a rotary mechanism, wherein: the rotary mechanism is configured to allow rotation of the combined cutting and pipe removal tool when the column is resting on a plug in the well tubing.

19. Apparatus, according to claim 18, characterized in that the combined cutting and pipe removal tool comprises a plurality of blades, each blade having a cutting edge for forming a circumferential cut in the well pipe and a milling surface for milling the well pipe when rotated.

20. Apparatus, according to claim 19, characterized in that the blades are movable between a retracted configuration, in which they are inside the tool body, and an extended configuration, in which they extend radially outward from the body for use.

21. Apparatus, according to claim 20, characterized in that the wellbore assembly comprises a tensioning device, the tensioning device configured to apply a constant load on the combined pipe cutting and stripping tool when the blades are in the extended configuration.

22. Apparatus, according to any one of claims 18 to 21, characterized in that the downhole assembly comprises a motor and the combined pipe cutting and removal tool is located between the motor and the rotary attachment.

23. Apparatus according to claim 22, characterized in that the motor is a left-hand positive displacement motor.

24. Apparatus, according to any one of claims 18 to 23, characterized in that the tubular column is coiled tubing.

25. Apparatus, according to any one of claims 18 to 23, characterized in that the tubular column is a drill pipe with a diameter of less than 178 mm (7) .

26. Apparatus, according to claim 25, characterized in that the tubular column has a diameter of less than 114 mm (4.5 in). Petition 870250095013, dated 10 / 17 / 2025, pp. 35 / 39

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