CABEÇA DE POÇO, SISTEMA DE TUBULAÇÃO DE POÇO, E, MÉTODO DE OPERAÇÃO DE UM POÇO

Abstract

ROTATING WELLHEAD AND CENTRALIZER. A wellhead is disclosed that includes a casing head, a pipe hanger, and a rotation assembly connected to the pipe hanger. The pipe hanger is rotatable relative to the casing head, and this rotation is effected by the rotation assembly. A centralizer for use with tubing in a well is also disclosed. The centralizer has a first sleeve, a second sleeve, and a body that has a first band and a second band connected by several resiliently deformable members. The bands extend around the sleeves, and the bands can move relative to their respective sleeves. This can allow the centralizer to be fitted to the tubing without requiring tight tubing size tolerances, for example, and can reduce friction between the body and the tubing to allow the tubing to be rotated within the casing during use.

Description

1 / 19 Wellhead, well piping system, and well operation method. Background of the Invention

[001] The present invention generally relates to equipment and methods used in wells, such as oil and / or gas wells, including wells for various mining services, such as pastefill, and more particularly to wellheads and casing and tubing, and methods of operating such equipment. Previous Order

[002] The present application claims priority from Australian Provisional Patent Application Number 2020900706, the content of which is incorporated herein in its entirety. Description of the state of the art

[003] Reference in this descriptive report to any previous publication (or information derived therefrom), or to any known matter, is not and should not be taken as an acknowledgment or admission or any form of suggestion that the previous publication (or information derived therefrom) or known matter is part of the common general knowledge in the field to which this descriptive report refers.

[004] The casing and tubing used in a typical well can often be used to transport particularly abrasive material. For example, the casing and tubing may be used to move drilling mud or slurries which may be composed of a wide variety of products, which may include abrasive components such as sand or rock fragments. In another example, at the end of a well's life or to fill a void or underground space (mining backfill), it may be desirable to pump concrete into the well through the casing and tubing. Again, this may be a highly abrasive material.

[005] Although it is generally desirable that a well borehole Petition 870260060662, dated 06 / 22 / 2026, page 10 / 58 2 / 19 While vertical drilling is possible, the practical reality of drilling often proves this not to be the case. When this occurs, the abrasive material passing through the inclined casing or pipe results in one side of the casing or pipe being subject to greater wear due to the effects of gravity. That is, the lower side of the inclined casing or pipe wears more than the upper side. This different wear rate can be further exacerbated if the material passing through the casing or pipe only partially fills the casing or pipe, resulting in significant wear on one side of the casing or pipe and virtually no wear on the opposite side.

[006] Although casing and tubing are typically made of thick-walled steel, wear can be significant enough over time to cause a failure in the casing and tubing wall. However, wear rates are not always predictable and cannot usually be measured, making it very difficult to predict these failures. As a result, casing and tubing can fail unexpectedly, leading to significant unplanned downtime of well operation. Furthermore, in a situation where cement is being carried through the casing and tubing, this can result in the casing becoming filled with cement, potentially requiring complete re-drilling of the well, which is extremely expensive.

[007] Periodic replacement of the lining or piping is possible, however, this is still a time-consuming and expensive operation. Therefore, this is not a task that is desirable to perform if it is not necessary. As such, it is desirable to provide a means to increase the service life of the lining or piping, or at least to better predict wear rates or solve state-of-the-art problems. Summary of the Present Invention Petition 870260060662, dated 06 / 22 / 2026, page 11 / 58 3 / 19

[008] According to a broad embodiment of the invention, a wellhead is provided, comprising: a) a coating head; b) a production string hanger; and c) a rotating assembly connected to the production column hanger; where the production string hanger rotates relative to the casing head, and this rotation is effected by the rotation assembly.

[009] In one embodiment, the rotation assembly is connected between the casing head and the production string hanger.

[0010] In one embodiment, the rotation assembly comprises a linear actuator.

[0011] In one embodiment, the linear actuator is articulatedly connected to the production column hanger in a manner that allows the location of the connection to be adjusted around a circumference of the production column hanger.

[0012] In one embodiment, the production column hanger comprises a peripheral groove, in which a tab of the rotation assembly is inserted into the groove for connecting the rotation assembly to the production column hanger.

[0013] In one embodiment, the production column hanger has a plurality of holes for attaching the rotary assembly tab in one of a plurality of positions within the groove.

[0014] In one embodiment, the rotating assembly comprises a gear mechanism.

[0015] In one embodiment, a bearing is arranged between the casing head and the production string hanger.

[0016] In one embodiment, a seal is provided between the casing head and the production string hanger. Petition 870260060662, dated 06 / 22 / 2026, page 12 / 58 4 / 19

[0017] In one embodiment, the production string hanger comprises a conduit that extends through the production string hanger and allows fluid communication through the production string hanger to a void between the casing and the tubing.

[0018] According to another broad embodiment of the invention, a centralizer is provided for use with piping in a well, the centralizer comprising: a) a first glove and a second glove; b) a body comprising a first ring and a second ring connected to each other by a plurality of resiliently deformable members; wherein the first ring extends around the first glove and the second ring extends around the second glove, and wherein the rings are able to move relative to their respective gloves.

[0019] In one embodiment, the gloves each comprise a collar to limit the movement of the ring along the glove.

[0020] In one embodiment, the sleeves comprise one or more through holes with headless screws fitted, so that the sleeves can be fitted and secured to the piping.

[0021] In one embodiment, a bearing is arranged between each of the rings and the respective sleeve that allows relative rotational and longitudinal movement.

[0022] In one embodiment, the bearings are in the form of ball bearings retained in a groove on an inner surface of each of the rings.

[0023] According to another broad embodiment of the invention, a centralizer is provided for use with piping in a well, the centralizer comprising a body comprising a first ring and a second ring connected to each other by a plurality of resiliently deformable members, wherein the first ring and the second ring are configured to extend around the piping and wherein a bearing is disposed in Petition 870260060662, dated 06 / 22 / 2026, page 13 / 58 5 / 19 inner surface of each of the rings that allows relative rotational and longitudinal movement between the rings and the tubing.

[0024] In one embodiment, the bearings are in the form of ball bearings retained in a groove on an inner surface of each of the rings.

[0025] In one embodiment, in use, a collar is fitted to the tubing on one or both sides of the centralizer to limit the movement of the rings along the tubing.

[0026] According to another broad embodiment of the invention, a well piping system is provided, comprising a wellhead substantially as defined herein, and piping suspended from the wellhead.

[0027] In one embodiment, the well piping system further comprises one or more centralizers fitted into the piping, the centralizers being substantially as defined herein.

[0028] According to another broad embodiment of the invention, a method of operating a well is provided, the well comprising casing, a wellhead connected to the casing and piping within the casing suspended from the wellhead, the method comprising the steps of: i) operate the well for a period of time; and ii) rotate the piping.

[0029] In one embodiment, the pipe is rotated periodically.

[0030] In one embodiment, the pipe turning step comprises the following sub-steps: i) extend an actuator from a rotary assembly that is connected to a production column hanger; ii) Disconnect the rotation assembly from the production column hanger; iii) contract the actuator; and iv) reconnect the rotation assembly to the column hanger. Petition 870260060662, dated 06 / 22 / 2026, page 14 / 58 6 / 19 of production.

[0031] In one embodiment, the pipe turning step comprises the following sub-steps: i) contract an actuator of a rotating assembly that is connected to a production column hanger; ii) Disconnect the rotation assembly from the production column hanger; iii) extend the actuator; and iv) reconnect the rotation assembly to the production column hanger.

[0032] It will be appreciated that the broad forms of the invention and their respective features can be used together and / or independently, and the reference to separate broad forms is not intended to be limiting. Furthermore, it will be appreciated that the features of the method can be realized using the system or apparatus and that the features of the system or apparatus can be implemented using the method. Brief description of the drawings

[0033] Several examples and embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is an isometric view of a wellhead according to an embodiment of the invention; Figure 2 is a cross-sectional side view of the wellhead from Figure 1; Figure 3 is another isometric view of the wellhead from Figure 1; Figure 4 is a cross-sectional side view of the wellhead from Figure 1; Figure 5 is an isometric view of a centralizer according to an embodiment of the invention; Figure 6 is an end view of the centralizer from Figure 5; Petition 870260060662, dated 06 / 22 / 2026, page 15 / 58 7 / 19 Figure 7 is a side view of the centering device shown in Figure 5; and Figure 8 is a cross-sectional side view of the centering device of Figure 5 taken along Section JJ of Figure 6. Detailed Description of Preferred Options

[0034] An example of a wellhead according to an embodiment of the invention will now be described. The wellhead has a casing head attached to an upper end of a well casing and a production string hanger that is connected to tubing located within the casing.

[0035] The casing and tubing used in the well may be of any suitable design. For example, the casing may typically be sections of steel tubing that are inserted into the wellbore and may be cemented in place filling any space between the wellbore and the outside of the casing. The tubing may also be formed from connected sections of steel tubing, with the tubing situated within the casing and having an annular space between the tubing and the casing.

[0036] It will be appreciated that the tubing and / or casing may be supported from the bottom of the well, in addition to or instead of being supported from the top of the well. In this sense, the term hanger, as used in relation to the production string hanger, should be interpreted in a broad sense, as it may simply hold the tubing in position rather than supporting the entire weight of the tubing. Therefore, throughout the descriptive report, it will be understood that the tubing and / or casing described may be supported from one or both the top and bottom of the well.

[0037] The wellhead includes a rotation assembly that is connected to the production string hanger. The rotation assembly can be used to rotate the string hanger. Petition 870260060662, dated 06 / 22 / 2026, page 16 / 58 8 / 19 production in relation to the casing head. As the tubing is connected to the production string hanger, this, in turn, results in the tubing rotating within the casing.

[0038] Allowing the piping to be rotated in this manner is advantageous as it can extend the piping's service life. As discussed above, the movement of abrasive materials through the piping can result in significantly greater wear on the underside of the piping than on the upper side. However, by rotating the piping, this wear can be spread more evenly around the circumference of the piping, dramatically increasing the time before piping failure.

[0039] Other optional and / or advantageous wellhead configurations will now be described.

[0040] The rotation assembly can be connected between the casing head and the production string hanger. In alternative embodiments, however, the rotation assembly can extend from the production string hanger to some other suitable component or location, such as a wellhead base plate, for example.

[0041] Preferably, the rotating assembly uses a linear actuator to effect the movement of the production string hanger. The linear actuator will typically be a hydraulic ram, but may alternatively be any suitable device as will be known to those skilled in the art, such as, but not limited to, a pneumatic or electric ram.

[0042] The linear actuator may preferably be articulatedly connected to the production column hanger in a manner that allows the connection location to be adjusted around a circumference of the production column hanger. For example, the production column hanger may be formed with a peripheral groove, so that a tab of the rotation assembly can be inserted into the groove for connection. Petition 870260060662, dated 06 / 22 / 2026, page 17 / 58 9 / 19 of the rotation assembly to the production column hanger. In such an example, the production column hanger may also have a plurality of holes spaced around the length of the groove to secure the rotation assembly tab in one of a plurality of positions within the groove. In another similar example, the production column hanger may have angled slots instead of holes, which receive pins from the rotation assembly, thus forming a ratchet-type connection.

[0043] In an alternative embodiment, the rotation assembly may use a gear mechanism to effect the movement of the production column hanger. For example, the production column hanger may have teeth around an outer circumference, which may engage and be rotated by a smaller gear operated by a motor, with or without additional gears and / or clutches. Of course, it will be appreciated that many other forms of gear mechanism may also be used.

[0044] To assist in the rotation of the production string hanger, a bearing may be disposed between the casing head and the production string hanger. For example, a thrust bearing may be placed between an upper surface of the casing head and a lower surface of the production string hanger. This bearing may be partially embedded in one or both surfaces. It will be appreciated by those skilled in the art that various forms of bearings are widely suitable for this purpose.

[0045] Additionally, or alternatively, a seal may also be provided between the casing head and the production string hanger. For example, in the case where a bearing is used, an O-ring may also be positioned inside and / or outside the bearing.

[0046] In an exemplary embodiment, the production string hanger may have one or more conduits that extend through the production string hanger and allow fluidic communication. Petition 870260060662, dated 06 / 22 / 2026, page 18 / 58 10 / 19 through the production string hanger to a void between the casing and the tubing. This space outside the tubing is not normally used; however, providing such a conduit through the production string hanger to allow access to this space can be useful in some situations, such as in the case of tubing failure. In another example, access to this void through the conduit can be used to monitor any changes in communication, such as an increase or decrease in pressure.

[0047] Normally, the piping is not exactly centered within the casing. As such, attempts to rotate the piping as described above may be resisted by friction between the piping and the casing. However, since piping is not normally designed to withstand large rotational forces, it may not be possible to rotate the piping from the top or bottom end.

[0048] Consequently, a centralizer that keeps the piping centered within the casing, but also allows for pipe rotation, may be necessary in some situations. An example of such a centralizer will now be described.

[0049] The centralizer has a first sleeve and a second sleeve. It also has a body with a first ring and a second ring that are connected to each other by a plurality of resiliently deformable members. The first ring extends around the first sleeve and the second ring extends around the second sleeve.

[0050] The rings are able to move relative to their respective sleeves. In this way, the sleeves can be fitted over the piping and do not need to be able to move relative to the piping. Instead, the sleeves provide a surface with sufficient tolerance so that the rings can move over these sleeve surfaces.

[0051] Deformable members can be outwardly curved strips, as they are known to be used in centralizers of Petition 870260060662, dated 06 / 22 / 2026, page 19 / 58 11 / 19 state of the art, which allow the centralizer to rest against the inside of the casing and bend to accommodate diameter variations and also to allow some movement of the piping during use.

[0052] Although prior art centralizers may be designed to allow some movement between the centralizer and the piping, this is typically only sufficient to allow bending of the curved strips during use. That is, the tolerances used and the designs would allow limited movement, but would still require overcoming significant friction. Therefore, an operation such as pipe rotation may still not be possible, as the combined friction of many of these prior art centralizers would be too great for the piping to withstand when rotation is attempted from an upper end.

[0053] The present embodiment of the centralizer described above is advantageous because it greatly reduces this friction, which means that rotation of the pipe becomes possible. It also achieves this using standard piping, without any modification required, even if the outer surface of the pipe does not have a consistent enough diameter and / or is not a smooth surface.

[0054] Other optional and / or advantageous centralizer configurations will now be described.

[0055] The gloves may each comprise a collar to limit the movement of the ring along the glove. For example, collars may be provided at the outer ends of the gloves so that the rings cannot move beyond the ends of the gloves. Alternatively, it may be possible to place collars at the inner ends of the gloves to achieve the same result.

[0056] It is preferable that the sleeves can be attached to the piping. In one example, this can be achieved by providing the sleeves with one or more through holes with screws without Petition 870260060662, dated 06 / 22 / 2026, page 20 / 58 12 / 19 head screws fitted into them. This may allow the sleeves to be fitted over the pipe and secured in place by tightening the headless screws on the sides of the pipe.

[0057] To assist in the movement of the rings in the sleeves, a bearing may be disposed between each of the rings and the respective sleeve. These bearings preferably allow relative movements both rotational and longitudinal. This means that the lateral movement of the pipe due to the bending of the deformable members can be accommodated by the rings sliding along the sleeves in a longitudinal direction, while rotation of the pipe is also possible by allowing the sleeves to move in a rotational direction within the rings.

[0058] In one example, the bearings may be in the form of ball bearings retained in a groove on an inner surface of each of the rings. It will be appreciated, however, that alternative forms of bearing may be known to those skilled in the art and may also be used in the present situation.

[0059] In some situations, an alternative embodiment of a centralizer may be suitable. This alternative centralizer may have a body with a first ring and a second ring connected to each other by a plurality of resiliently deformable members, where the first ring and the second ring are fitted directly onto the piping. A bearing may be disposed on the inner surface of each of the rings, allowing relative rotational and longitudinal movement between the rings and the piping.

[0060] As noted above, the outer surface of the tubing may not be particularly smooth or consistent in diameter, therefore it may be necessary to have slightly oversized centralizer components to account for these poor tolerances. In one example, the bearings may be in the form of ball bearings retained in a groove. Petition 870260060662, dated 06 / 22 / 2026, page 21 / 58 13 / 19 on an inner surface of each of the rings. Similarly, it may be beneficial to have oversized ball bearings to accommodate variations in the outer surface of the tubing.

[0061] Advantageously, in some embodiments, a collar may be fitted to the tubing on one or both sides of the centralizer to limit the movement of the rings along the tubing. These collars may be broadly similar to the sleeves described earlier, but instead of the rings extending around the sleeves, the rings will abut the collar to limit movement in a specific direction.

[0062] It will be appreciated that the centralizer as described above can be used in conjunction with the wellhead as described, but can also be used with some alternative wellheads that may or may not allow pipe rotation. Similarly, the wellhead described can be used with the centralizer as described, but can also be used separately or with alternative centralizer designs. Each of the wellhead and the centralizer are devices that allow an operation to be performed where the pipe in a well can be rotated.

[0063] Advantageously, however, a well piping system may include a wellhead as described above with piping suspended from the wellhead, as well as one or more centralizers fitted to the piping, where the centralizers are also described above. Such a well piping system may be used to perform a method of operating a well, an example of which will now be described.

[0064] The method of operating a well may include the steps of operating the well over a period of time and rotating the tubing. For example, the tubing may be rotated periodically to distribute wear on the tubing as evenly as possible.

[0065] The pipe turning step may involve extending Petition 870260060662, dated 06 / 22 / 2026, page 22 / 58 14 / 19 A rotating assembly actuator that is connected to a production string hanger, disconnect the rotating assembly from the production string hanger, retract the actuator, and reconnect the rotating assembly to the production string hanger. Alternatively, the pipe rotating step may involve retracting the rotating assembly actuator, disconnecting the rotating assembly from the production string hanger, extending the actuator, and reconnecting the rotating assembly to the production string hanger.

[0066] When the tubing is rotated from the top by the wellhead in this manner, centralizers can be used to keep the tubing centrally within the casing. As described above, centralizers provide a means for the tubing to rotate with reduced resistance to contact with the casing. [00 67] An example of a wellhead design will now be described with reference to Figures 1 to 4.

[0068] With reference to Figure 1, a wellhead 100 is shown which includes a base plate 101 with elevation points 102. A casing head 104 is fitted to the base plate 101 and a production string hanger 107 is fitted to the casing head 104.

[0069] A rotary assembly 110 includes a hydraulic actuator 111 articulatedly connected at one end to the coating head 104. This connection is achieved by a screw 112 inserted through and into a hole 113 in the coating head 104. At the other end, the actuator 111 is connected to the production column hanger 107 by a bracket 115. The bracket 115 fits into a groove 116 in the production column hanger 107 and is secured in place using one or more holes 117 in the production column hanger 107 and a fastener (not shown).

[0070] It will be appreciated that the extension or contraction of the actuator Petition 870260060662, dated 06 / 22 / 2026, page 23 / 58 15 / 19 111 causes the production column hanger 107 to rotate relative to the coating head 104. When the actuator 111 reaches the end of its travel, the support 115 can be disconnected from the production column hanger 107, moved along the groove 116 and fixed in a different location.

[0071] For example, extending actuator 111 will cause production column hanger 107 to rotate counterclockwise. Support 115 can then be disconnected and actuator 111 retracted, causing support 115 to move along groove 116 clockwise. Support 115 can then be reconnected to production column hanger 107 to fix it in position or for further rotation. It will be appreciated that the reverse actions can also be used for rotation in the opposite direction.

[0072] With reference to Figure 2, a bearing 120 is located between the coating head 104 and the production column hanger 107, allowing relative rotation to occur more easily. This bearing 120 is in the form of ball bearings situated in cooperating grooves; however, it will be appreciated that other forms of thrust bearings may also be used. An O-ring type seal 122 is also located on both sides of the bearing 120.

[0073] The pipe 108 is fixed and suspended from the production string hanger 107. Similarly, the casing 109 extends downwards from the casing head 104, with a gap 124 located between the pipe 108 and the casing 109.

[0074] With reference to Figures 3 and 4, several conduits 130 extend through the production string hanger 107, each connecting a port 131 at a location above the casing hanger 104 to an opening 132 in the space 124 between the casing 109 and the tubing 108. That is, conduit 130 allows fluid communication through the production string hanger 107 to the space immediately outside the tubing 108. Petition 870260060662, dated 06 / 22 / 2026, p. 24 / 58 16 / 19 or immediately inside coating 109.

[0075] Pipe 108 is in fluid communication with an upper flange 140 and a central void 141. Rotation of the production string hanger 107 occurs without any corresponding rotation of the upper flange 140. This flange 140 provides a connection point for associated above-ground or below-ground equipment. As such, rotation of the production string hanger 107 and pipe 108 occurs without any effect or modification required on the inlet / outlet connection.

[0076] An example of a centralizer embodiment will now be described with reference to Figures 5 to 8.

[0077] With reference to Figure 5, a centralizer 200 is shown having a first end 201 and a second end 202, with a sleeve 204 located at each end. A body 205 of the centralizer 200 extends between the sleeves 204 and includes a ring 206 at each end fitted over each of the sleeves 204. Several resiliently deformable members 207 extend between the rings 206 and are curved outwards about a longitudinal axis of the centralizer 200.

[0078] The rings 206 are capable of moving relative to their respective sleeves 204, both rotationally and longitudinally. With reference to Figure 8, the bearings 210 are located between the sleeves 204 and the rings 206. Specifically, the ball bearings are seated in a groove on an inner surface of the rings 206. It will be appreciated, however, that it may be possible to use alternative bearing forms in other embodiments. The bearings 210 used here, however, are advantageous as they allow relative displacement in both directions as required.

[0079] Each of the gloves 204 has a collar 212 to limit the movement of the ring 206 along the glove 204. This prevents the ring 206 from moving too far and passing beyond the end of the glove. Petition 870260060662, dated 06 / 22 / 2026, page 25 / 58 17 / 19 204.

[0080] The 204 sleeves also have several through holes 214 into which headless screws can be fitted. This allows the 204 sleeves to be fitted over the pipe and secured in place by tightening the headless screws against the outer surface of the pipe. The holes 214 are located in the collar 212 so that the headless screws do not interfere with the movement of the rings 206 over the 204 sleeves.

[0081] The centralizer 200 can be fitted to the piping to maintain the piping in a central position within the casing. The deformable members 207 can press against the inside of the casing and provide a suspension shape where vibrations can be allowed and absorbed, with the members 207 flexing as needed. If necessary, the rings 206 can slide along the sleeves 204 in a longitudinal direction as the members 207 bend, resulting in a change in their effective length.

[0082] Unlike known centralizers, however, the embodiment presently described still allows the pipe to be rotated within the casing. That is, the sleeves 204 can remain fixed to the pipe, with the body 205 remaining fixed relative to the casing, with these components capable of rotating relative to each other thanks to the bearings 210 between the sleeves 204 and the rings 206.

[0083] The use of the 204 sleeves is important because the outer surface of the pipe is not always created with sufficient tolerance to allow the 206 rings to be fitted directly onto the pipe. Furthermore, the 212 collars suggest that the 206 rings can move in a longitudinal direction, but the extent of this movement may still be limited. Therefore, the present invention allows the 200 centralizer to be fitted directly onto any available pipe while still maintaining these benefits. Petition 870260060662, dated 06 / 22 / 2026, page 26 / 58 18 / 19

[0084] Although the wellhead 100 and the centralizer 200 can be used separately, it will be appreciated that a particularly advantageous well piping system can be created using these components together. That is, the wellhead 100, which can be used to rotate the piping that is suspended from this device, will operate very effectively when the piping also utilizes the centralizers 200, which allow for pipe rotation.

[0085] A well using this system can be operated for a period of time before rotating the tubing. For example, the tubing can be rotated 180° or any other suitable value that is not a full revolution. This will result in any areas of greater wear on the tubing being moved, so that a portion that has experienced less wear is now in this position to be subject to greater wear going forward. In this way, the service life of the tubing can be increased.

[0086] The pipe can be rotated periodically, with the degree of rotation being chosen so that the wear on the pipe walls is distributed as evenly as possible.

[0087] In the preceding description of preferred embodiments, specific terminology was used for clarity. However, the invention is not intended to be limited to the specific terms thus selected, and it should be understood that each specific term includes all technical equivalents that operate in a similar manner to achieve a similar technical objective. Terms such as front and back, inside and outside, above and below, and the like are used as words of convenience to provide points of reference and should not be interpreted as limiting terms.

[0088] Throughout this descriptive report and the claims that follow, unless the context requires otherwise, the word understand and variations such as Petition 870260060662, dated 06 / 22 / 2026, page 27 / 58 19 / 19 includes or encompassing, shall be understood as implying the inclusion of a stated integer or group of integers or steps, but not the exclusion of any other integer or group of integers. As used in this document and unless otherwise indicated, the term approximately means ± 20%.

[0089] Those skilled in the art will appreciate that numerous variations and modifications will become apparent. All such variations and modifications that become evident to those skilled in the art should be considered within the spirit and scope in which the invention appears broadly described beforehand. Petition 870260060662, dated 06 / 22 / 2026, page 28 / 58

Claims

1 / 4 CLAIMS 1. Wellhead (100), comprising: a) a casing head (104); b) a production string hanger (107); and c) a rotation assembly (110) connected to the production string hanger (107); wherein the production string hanger (107) is rotatable relative to the casing head (104) and this rotation is effected by the rotation assembly (110);wherein the production column hanger (107) is rotatable relative to the coating head (104) and this rotation is effected by the rotation assembly (110), characterized in that the rotation assembly (110) comprises a linear actuator (111) which is pivotally connected to the production column hanger (107) so as to allow the location of the connection to be adjusted around a circumference of the production column hanger (107), and the production column hanger (107) comprises a peripheral groove (116), and wherein a support (115) of the rotation assembly (110) is inserted into the groove (116) for connection of the rotation assembly (110) to the production column hanger (107).

2. Wellhead (100), according to claim 1, characterized in that the rotation assembly (110) is connected between the casing head (104) and the production string hanger (107).

3. Wellhead (100), according to claim 1 or 2, characterized in that the production string hanger (107) has a plurality of holes (117) for fixing the support (115) of the rotation assembly (110) in one of a plurality of positions within the groove (116).

4. Wellhead (100), according to claim 1 or 2, characterized in that a bearing (120) is disposed between the casing head (104) and the production string hanger (107).

5. Wellhead (100), according to claim 1 or 2, characterized in that a seal (122) is disposed between the casing head (104) and the production string hanger (107).

6. Wellhead (100), according to any one of claims 1 to 5, characterized in that the production string hanger (107) comprises a conduit (130) that extends through the production string hanger (107) and allows fluid communication through the production string hanger (107) to a void (141) between a casing (109) that is connected to the casing head (104) and a pipe (108) that is connected to the production string hanger (107).

7. Well piping system, characterized in that it comprises: a wellhead (100), as defined in any one of claims 1 to 6; a pipe (108) suspended from the wellhead (100); and one or more centralizers (200) fitted to the pipe (108), the centralizers (200) comprising one of: i. a first sleeve (204), a second sleeve (204) and a body (205) comprising a first ring (206) and a second ring (206) connected to each other by a plurality of resiliently deformable members (207), wherein the first ring (206) extends around the first sleeve (204) and the second ring (206) extends around the second sleeve (204), and wherein the rings (206) are capable of moving relative to their respective sleeves (204); and ii.a first ring (206) and a second ring (206) connected to each other by a plurality of resiliently deformable members (207), wherein the first ring (206) and the second ring (206) are configured to extend around the pipe (108), and wherein a bearing (210) is disposed on an inner surface of each of the rings (206) which allows relative rotational and longitudinal movement between the rings (206) and the pipe (108).

8. Method of operating a well, the well comprising a casing (109), a wellhead (100) connected to the casing (109) and piping (108) within the casing (109) suspended from the wellhead (100), the method comprising the steps of: i) operating the well for a period of time;and ii) rotating the tubing, characterized in that the wellhead (100) comprises a casing head (104), a production string hanger (107) and a rotation assembly (110) connected to the production string hanger (107), wherein the production string hanger (107) is rotatable relative to the casing head (104) and this rotation is effected by the rotation assembly (110), the rotation assembly (110) comprises a linear actuator (111) which is pivotally connected to the production string hanger (107) so as to allow the location of the connection to be adjusted around a circumference of the production string hanger (107), the production string hanger (107) comprises a peripheral groove (116), and the rotation assembly (110) comprises a support (115) which is inserted into the groove (116) for connection of the rotation assembly (110) to the production string hanger. production (107).; 9. Method according to claim 8, characterized in that the pipe (108) is rotated periodically.

10. Method according to claim 8 or 9, characterized in that the step of rotating the pipe (108) comprises one of: a) substeps of: Petition 870260060662, dated 06 / 22 / 2026, page 31 / 58 4 / 4 i) extending a linear actuator (111) from a rotation assembly (110) that is connected to a production column hanger (107); ii) disconnecting the rotation assembly (110) from the production column hanger (107); iii) contracting the linear actuator (111); and iv) reconnecting the rotation assembly (110) to the production column hanger (107); and b) substeps of: i) contracting a linear actuator (111) from a rotation assembly (110) that is connected to a production column hanger (107); ii) disconnect the rotation assembly (110) from the production column hanger (107); iii) extend the linear actuator (111); and iv) reconnect the rotation assembly (110) to the production column hanger (107). Petition 870260060662, dated 06 / 22 / 2026, page 32 / 58

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