Downhole tool string
By introducing the combination of tool body, processing tools, shifting elements and fixed-distance elements into the downhole tool pipe column, the stability of the drill bit shifting and processing in the wall of the metal well pipe structure in the radial direction is solved, and safety is achieved Efficient porous drilling operation.
Patent Information
- Application Number
- CN202380032764.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-11
- Filing Date
- 2023-04-19
- Publication Date
- 2024-12-17
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
During the drilling process, the drill bit is prone to breaking, and the prior art is difficult to effectively displace and process the walls of the metal well pipe structure in the radial direction, resulting in failure of the processing operation.
An underground tool pipe column is designed, including a tool body, a processing tool for operation, a first shifting element and a first distance element. Through the cooperation of these elements, the tool body can be radially located on the wall of the metal well pipe structure. The direction is shifted, and the distance between the tool and the well pipe wall is ensured through the first fixed distance element, to avoid chip accumulation, and to ensure the stable operation of the processing tool.
The stable processing of the wall of the metal well pipe structure is achieved, which reduces the risk of breakage of the drilling tool, improves processing efficiency and safety, avoids the use of explosives, and can complete the drilling operation of multiple holes in a short distance. .
Smart Images
Figure CN119156482A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a downhole tool string for displacing at least a tool section in a well in a radial direction in a wall of a metal well tubular structure extending in an axial extension direction perpendicular to the radial direction. Furthermore, the invention relates to a downhole system. Background Art
[0002] When drilling in a casing in an oil or gas well, the tool section comprising the drill bit is displaced in a radial direction perpendicular to the axial extension direction of the casing. However, experiments have shown that the drill bit sometimes breaks. Summary of the invention
[0003] An object of the present invention is to wholly or partially overcome the above-mentioned shortcomings and deficiencies in the prior art. More particularly, an object is to provide an improved downhole tool string having an operational machining tool such as a drill bit that can extend in a radial direction and can perform machining operations without breaking.
[0004] The above objects and numerous other objects, advantages and features which will become apparent from the following description are achieved by the solution according to the present invention, namely by a downhole tool string for displacing at least a tool section in a radial direction in a well in a wall of a metal well tubular structure, the metal well tubular structure extending in an axial direction perpendicular to / relative to the radial direction, the downhole tool string comprising:
[0005] a tool body having an outer surface and a tool center axis in an axial direction, a central plane extending along and containing the tool center axis, thereby dividing the tool body into a first body half and a second body half;
[0006] - an operational machining tool for performing machining operations in a metal well tubular structure, such as drilling a hole in a wall, and capable of protruding from an outer surface of the first body half in a first radial direction perpendicular to / relative to a central axis of the tool; and
[0007] a first displacement element which can protrude from an outer surface of the second body half of the tool body for displacing the tool body towards the wall portion so as to arrange the operating working tool close to the wall portion, the first displacement element being telescopic between a retracted position and a protruding position,
[0008] The downhole tool string also includes a first distance element, which can extend from the outer surface of the first main body half to ensure the distance between the outer surface and the wall of the metal well pipe structure when the first displacement element is in the protruding position. The first distance element has a retracted position and a protruding position.
[0009] Thus, a downhole tool string for displacing at least a tool section in a well in a radial direction in a wall of a metallic well tubular structure extending in an axial direction perpendicular to the radial direction may comprise:
[0010] a tool body having an outer surface and a tool center axis in an axial direction, a central plane extending along and containing the tool center axis, thereby dividing the tool body into a first body half and a second body half;
[0011] - an operational machining tool for performing machining operations in a metal well tubular structure, such as drilling a hole in a wall, and capable of protruding from an outer surface of the first body half in a first radial direction perpendicular to a central axis of the tool; and
[0012] a first displacement element which can protrude from an outer surface of the second body half of the tool body for displacing the tool body towards the wall portion so as to arrange the operating working tool close to the wall portion, the first displacement element being telescopic between a retracted position and a protruding position,
[0013] The downhole tool string also includes a first distance element, which can extend from the outer surface of the first main body half, and the first distance element has a retracted position and an extended position. In the extended position of the first distance element, a distance is provided between the outer surface and the wall of the metal well pipe structure.
[0014] The operative machining tool may be a drill bit for cutting a hole in a metal well tubular structure by rotating about its own central axis.
[0015] Thus, the downhole tool string may be a drilling downhole tool string for drilling at least one hole in a wall of a metallic well tubular structure.
[0016] Furthermore, the distance may be less than 10 mm, preferably less than 5 mm.
[0017] Furthermore, the operating processing tool may be a drill.
[0018] Furthermore, the operating machining tool can have a grinding insert or a cutting insert.
[0019] Furthermore, the first displacement element in the protruding position may protrude from the outer surface by a first length, the first distance element in the protruding position protrudes from the outer surface by a second length, and the first length is longer than the second length.
[0020] Furthermore, the first length may be greater than 200% of the second length, preferably greater than 300% of the second length, more preferably greater than 400% of the second length, even more preferably greater than 500% of the second length.
[0021] Furthermore, before the machining operation begins, the operative machining tool in the extended position may have a third length, the second length being less than 50% of the third length.
[0022] Furthermore, before the machining operation begins, the operating machining tool in the initial protruding position may have a fourth length that is equal to or shorter than the second length.
[0023] Furthermore, the fourth length may be less than 10 mm, preferably less than 5 mm.
[0024] Furthermore, the first distance element may be arranged along the circumference of the tool body at an angle of 0° to ±90° to the operating machining tool, preferably at an angle of 5° to ±45° to the operating machining tool.
[0025] Furthermore, the first displacement element and the first distance element can be protruded by the same axial displacement in the tool body.
[0026] Furthermore, the first displacement element and the first distance element can be extended by means of hydraulic forces.
[0027] Furthermore, the first displacement element and the first distance element can be protruded by means of a piston inside the tool body.
[0028] Furthermore, the first displacement element and the first distance element can protrude through a shaft or a wedge inside the tool body.
[0029] The present invention may further comprise a second displacement element protruding from the second body half and arranged at an angle of 0-120°, preferably 5-120°, and more preferably 20-120° to the first displacement element along the circumference of the tool body.
[0030] In addition, the present invention may also include a second distance element, which protrudes from the first main body half and is arranged at an angle of 0-120° with the first distance element along the circumference of the tool body, preferably at an angle of 5-120° with the first distance element, and more preferably at an angle of 20-120° with the first distance element.
[0031] Furthermore, the first distance element and the second distance element may be arranged at equal distances from the first radial direction.
[0032] Furthermore, the displacement element and the distance element can protrude from the outer surface by pivoting about their respective pivot points.
[0033] Furthermore, the displacement element and the distance element may protrude from the outer surface by being displaced radially outwards.
[0034] Furthermore, the outer diameter of the tool body may be less than 79 mm, preferably less than 54 mm, ie, less than 2.125 inches.
[0035] Furthermore, the downhole tool string may comprise a first tool section, in which the operative machining tool is arranged, and a second tool section, in which the displacement element and the distance element are arranged.
[0036] Furthermore, the second tool section can be an anchoring section and the displacement element and the distance element can be anchoring elements.
[0037] Furthermore, the displacement element and the distance element may have a first end connected to the tool body and a second end for abutting against a wall of the metal well tubular structure.
[0038] Furthermore, the second end of each of the displacement element and the distance element may comprise a friction enhancing element, such as a tooth.
[0039] Furthermore, the downhole tool string may comprise a tool housing having a first opening through which the distance element protrudes and a second opening through which the displacement element protrudes.
[0040] Furthermore, the pivot point about which the displacement element rotates may be in the form of a shaft which is rotatably connected to the tool housing.
[0041] Furthermore, the pivot point about which the distance element rotates may be in the form of a shaft which is rotatably connected to the tool housing.
[0042] Finally, the present invention also relates to a downhole system, which comprises a downhole tool string and a driving unit, wherein the driving unit is used to propel the downhole tool string forward in the well, and the driving tool is, for example, a downhole tractor. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] The invention and its many advantages will be described in more detail below with reference to the attached schematic diagrams which show only some non-limiting embodiments for illustrative purposes, in which:
[0044] Figure 1 A downhole tool string is shown in a metallic well tubular structure of a well;
[0045] Figure 2A A portion of another downhole tool string is shown with an operational machining tool, a displacement element, and a distance element in a retracted position;
[0046] Figure 2B Shows Figure 2A A downhole tool string, wherein the displacement element and the distance element are shown in an extended position;
[0047] Figure 3 A schematic diagram showing a front view of another downhole tool string in a metal well tubular structure, wherein an operating tool, a displacement element and a distance element are shown in their extended positions;
[0048] Figure 4 A portion of another downhole tool string including an operational tool and a distance element in a first body half above a central plane is shown;
[0049] Figure 5 A schematic diagram showing a front view of a further downhole tool string comprising an operational machining tool, two displacement elements and two distance elements, wherein the displacement elements and the distance elements are shown in their protruding positions;
[0050] Fig. 6A and 6B A schematic diagram of another downhole tool string is shown, the downhole tool string comprising a displacement element and a distance element from Fig. 6A The retracted position shown moves to Figure 6B The shaft is shown in the extended position;
[0051] Fig. 7A and 7B A schematic diagram of another downhole tool string is shown, the downhole tool string comprising a displacement element and a distance element from Fig. 7A The retracted position shown moves to Figure 7B The wedge member is shown in the extended position; and
[0052] Fig. 8A and 8B A schematic diagram of another downhole tool string is shown, the downhole tool string comprising an axial sliding mandrel for moving a displacement element and a distance element from Fig. 8A The retracted position shown moves to Figure 8B Their protruding positions are shown.
[0053] All the figures are highly schematic and not necessarily to scale, and they show only those components which are necessary in order to elucidate the invention, other components being omitted or merely suggested. DETAILED DESCRIPTION
[0054] Figure 1 A downhole tool string 1 is shown for displacing at least a tool section or the entire downhole tool string itself in a well 2 in a radial direction R in a wall 3 of a metallic well tubular structure 4 extending in an axial direction L perpendicular to the radial direction. The downhole tool string 1 comprises a tool body 5 having an outer surface 6 and a tool centre axis 7 in the axial direction. Figure 1 A central plane P is shown, which extends along and lies within a tool central axis 7, and which divides the tool body into a first body half 8 and a second body half 9. The downhole tool string 1 also includes an operating tool 10 for performing an operation in a metallic well tubular structure, such as drilling a hole 11 (e.g., a hole 12) in a wall of a metallic well tubular structure such as a production casing. Figure 3 The downhole tool string 1 can therefore be used to open a plurality of holes, thereby forming a perforated area for allowing a production fluid (i.e., a hydrocarbon-containing fluid such as oil or gas) to enter the metal well pipe structure. The operating processing tool 10 can extend from the outer surface of the first body half along a first radial direction R perpendicular to the center axis of the tool, and the operating processing tool 10 is arranged in an opening 47 in the tool housing 27. The downhole tool string 1 also includes a first displacement element 12, 12A, which can extend from the outer surface of the second body half of the tool body, and is used to displace the tool body toward the wall portion 3 to arrange the operating processing tool 10 close to the wall portion. The first displacement element can be as shown in FIG. Figure 1 The retracted position shown and Figure 2B The downhole tool string further comprises a first distance element 14, 14A, which can extend from the outer surface of the first main body half, and is used to ensure that the distance d (such as the distance between the outer surface 6 and the wall 3 of the metal well pipe structure 4) is maintained when the first displacement element 12 is in the protruding position. Figure 2B The first distance element 14 has a Figure 1 and 2A The retracted position shown and Figure 2B The protrusion position is shown.
[0055] When performing a machining operation such as drilling a hole in the wall of a production casing, the drilling process generates chips, and if the distance element 14 does not ensure that a certain distance is maintained between the outer surface 6 of the tool body and the wall, the chips will accumulate around the drill bit and there will be no space / clearance to leave the drilling area, and the drilling operation will eventually stop because the accumulated chips will tighten around the drill bit, thereby hindering further rotation of the drill bit. Therefore, by having the distance element provide and ensure this distance, the chips can leave the drilling area, and the drilling operation is therefore no longer stopped because the chips do not accumulate around the drill bit. In addition, by having this distance, wellbore fluid can be flushed through the operating area, thereby removing the chips from the drill bit, and the heat provided by the drilling operation is easily dissipated from the drill bit.
[0056] For safety reasons, operators wish to avoid the use of explosives in wells and therefore increasingly desire to be able to form perforated areas in wells by machining out holes. The machining tools in prior art downhole tool strings are made to have the longest possible extension length, and the machining tools are positioned as close as possible to the object they are to machine, in order to provide the longest reach; however, sometimes these machining operations fail for unknown reasons. Therefore, in the tools of the prior art, the focus is on getting as close to the object as possible, and reaching as far into the object as possible. The distance element provides the opposite effect: the distance to enter the object to be machined is shorter, but the machining operation does not fail as often as with the tools of the prior art. Therefore, the initial position of the machining tool has only a very short length L4 from the outer surface of the tool body, if at all. Figure 3 As shown by the dotted line in .
[0057] Especially when machining by means of a rotating drill, the chips are rotated with the drill and have been shown to have a tendency to become stuck between the drill and the wall of the hole drilled by the drill. Drilling with the aid of a drill is safer than perforating an area with the aid of explosives, but a drill needs to be able to drill a large number of holes in order to "compete" with explosives in terms of the time taken for the perforation operation.
[0058] Figure 3 A cross-sectional view of a tool body 5 located in a well having a wall portion 3 is shown. A first displacement element 12 is shown in a protruding position extending from an outer surface 6 of the tool body 5, i.e. extending by a first length L1. The first displacement element 12 is located in the second body half 9 of the tool body 5. A first distance element 14 is shown in a protruding position in the first body half 8 of the tool body 5. The first distance element 14 extends from the outer surface 6 of the tool body 5 by a second length L2. Figure 3 In the embodiment, the first length L1 is longer than the second length L2. The first length L1 may be greater than 200%, preferably greater than 300%, more preferably greater than 400%, and even more preferably greater than 500% of the second length.
[0059] exist Figure 3 In the embodiment, the first distance element 14 is arranged at an angle α of about 20° to the operating processing tool 10. In another embodiment, the first distance element can be arranged at an angle α of 0° to ±90° to the operating processing tool along the circumference 15 of the tool body 5. Figure 4 In the embodiment, the angle relative to the operating machining tool 10 is 0°, ie the operating machining tool and the distance element 14 coincide along the circumference of the tool body.
[0060] The operating tool 10 projects along a radial direction R perpendicular to the tool center axis 7, and a plane P divides the first body half 8 and the second body half 9 of the tool body 5. The operating tool 10 is shown projecting into the wall 3 of the well when a hole 11 has been drilled or punched in the wall of the metal well tubular structure 4. In the projecting position, the operating tool 10 has a third length L3. The second length L2 is less than 50% of the third length L3.
[0061] like Figure 2A As shown, the first displacement element 12 and the first distance element 14 can be protruded by the same axial movement in the tool body 5. Figure 2A , the same axial movement is provided by a piston 16 (indicated by dashed lines) inside the tool body 5, which moves along the tool center axis 7 and is connected to the first displacement element 12 and the first distance element 14. The piston 16 comprises a first hole 45 (indicated by dashed lines) receiving the first end 25 of the distance element 14 and a second hole 46 (indicated by dashed lines) receiving the first end 25 of the displacement element 12. The piston 16 is moved along the tool center axis 7 by means of hydraulic force by a pressurized fluid pressed on the piston end face 48 (indicated by dashed lines). The displacement element 12 and the distance element 14 can protrude from the outer surface 6 by pivoting around their respective pivot points 19, 20 (indicated by dashed lines). The pivot point 19 about which the displacement element 12 rotates is in the form of a pin 33 rotatably connected to the inner surface of the tool housing 27, and the pivot point 20 about which the distance element 14 rotates is in the form of a pin 34 (indicated by dashed lines) rotatably connected to the inner surface of the tool housing 27. When the piston moves, the tool housing is stationary, so when the piston provides the same axial movement, the displacement element 12 and the distance element 14 are forced to protrude. Figure 1 As shown, the downhole tool string 1 includes a pump 51 to allow pressurized fluid to move the piston and radially move the operating processing tool outward. The downhole tool string 1 also includes a compensator 52 for ensuring that there is a small overpressure inside the tool string compared to the well pressure. The downhole tool string 1 also includes an electric motor 53 that drives the pump and rotates the drill bit through a shaft with the help of a gear (not shown). Figure 2AThe piston 16 shown by the dashed line in the figure is retracted by a spring / elastic member (not shown) partially located inside the piston, so that when the piston is moved by means of the pressurized fluid, the piston compresses the spring, and when the pressure is released, the spring decompresses, thereby moving the piston to its initial position and thereby moving the displacement element 12 and the distance element 14 to their retracted positions.
[0062] like Figure 1 As shown, the downhole tool string 1 may have a drive unit 30, such as a downhole tractor, wherein wheels 35 on a wheeled arm 36 provide a specific and approximately uniform distance from the tool body 5 to the wall 3. In order to displace the tool body relative to the wall 3, as shown in FIG. Figure 2B , Figure 3 and Figure 5 As shown, where the first body half 8 of the tool body 5 is moved closer to the wall 3 than the second body half 9, the downhole tool string can be controlled to retract the arm with wheels so that displacement is possible. In another embodiment, the downhole tool string can have a tool section that enables a first part of the downhole tool string with the processing tool 10 to be displaced while a second part of the downhole tool string with the drive unit 30 remains centered.
[0063] Fig. 6A A retracted position, ie a first position, of the first displacement element 12 and the first distance element 14 is shown. Figure 6B The protruding position of the first displacement element 12 and the first distance element 14 , ie the second position, is shown. The first displacement element 12 and the first distance element 14 can be protruded by means of a shaft 17 that rotates inside the tool body 5 .
[0064] Rotating the shaft 17 and thereby moving the movable shaft part 17A towards the fixed shaft part 17B will cause the displacement element 12 and the distance element 14 to protrude outwardly from the tool body 5. Fig. 6A and 6B In the embodiment, the lengths of the parts 60, 61 of the displacement element and the parts 60, 61 of the distance element are different, so in the protruding state of the displacement element 12 and the distance element 14, the first length L1 and the second length L2 will become different.
[0065] Fig. 7A and 7B A downhole tool string is shown, in which the displacement element 12 and the distance element 14 can protrude through a mandrel 41 driven by an electric motor (not shown). The mandrel interacts with the wedges 18 of the displacement element 12 and the distance element 14, because the displacement element 12 and the distance element 14 are wedge-shaped. The mandrel 41 has an inclined surface that abuts against the wedge-shaped displacement element 12 and the wedge-shaped distance element 14, but in another embodiment, the mandrel can have a non-inclined shape. Fig. 7A and 7BIn the embodiment of the invention, the two wedges 18 are of different sizes, so that the displacement element 12 protrudes more than the distance element 14. These wedges are connected to the tool housing 27 at a pivot point and are retracted by a torsion spring arranged at the pivot point. The spindle 41 is moved by hydraulic pressure, the internal spring is compressed, and the torsion spring is stretched as the spindle pushes the wedges outward. When the hydraulic pressure is released, the internal spring retracts the spindle and the torsion spring retracts the wedges.
[0066] Fig. 7A The wedge 18 and thus the displacement element 12 and the distance element 14 are shown in a retracted position, ie the first position. Figure 7B The wedge 18 and thus the displacement element 12 and the distance element 14 are shown in the protruding position (i.e. the second position). The wedge 18 is moved from the retracted position to the protruding position by pushing the spindle 41 in the direction of the arrow AR along the central axis 7 of the tool body 5. The different sizes of the two wedges will result in the two wedges protruding from the outer surface 6 of the tool body 5 by different lengths L1 and L2.
[0067] Figure 5 Shows something like Figure 3 A cross-sectional view of the Figure 5 In the embodiment, the downhole tool string further comprises a second displacement element 12B protruding from the second body half 9. The second displacement element 12B is arranged at an angle V of 0-120° with the first displacement element 12 along the circumference 15 of the tool body 5.
[0068] In addition, if Figure 5 As shown, the downhole tool string further comprises a second distance element 14B protruding from the first body half 8. The second distance element 14B is arranged at an angle β of 0-120° with the first distance element 14 along the circumference 15 of the tool body 5. Figure 5 In the embodiment, the second distance elements 14, 14B are arranged at an angle β of approximately 40°. Figure 5 In the embodiment, the angle β is about twice the angle α, but in another embodiment, the angle β may be greater than or less than twice the angle α. Therefore, the first and second distance elements may be arranged such that they are equidistant from the first radial direction R. Similarly, the distance elements 14, 14B may be arranged along the circumference of the tool body 5 such that they are equidistant from the first radial direction R.
[0069] like Figure 1 , 2AAs shown in FIG. 2B , the downhole tool string 1 includes a first tool section 21 and a second tool section 22, the operating processing tool 10 is arranged in the first tool section 21, and the shifting element and the distance element are arranged in the second tool section 22. By locating the operating processing tool in the first tool section which is arranged consecutively / continuously / sequentially with the second tool section along the tool center axis 7, the distance element can be arranged at the same radial position as the drill bit along the circumference of the tool body (e.g., Figure 4 ), and may protrude in the same radial direction as the operating processing tool, such as Figure 2B Therefore, the second tool section can also be used as an anchoring section 23, while the displacement element and the distance element are anchoring elements 24 for anchoring the downhole tool string in the axial direction. Figure 2A and 2B As shown, each of the displacement element 12 and the distance element 14 has a first end 25 connected to the tool body and a second end 26 for abutting against the wall of the metal well pipe structure. Each of the second ends 26 of the displacement element 12 and the distance element 14 includes a friction enhancing element 27B, such as teeth. The tool housing 27 includes a first opening 31 and a second opening 32 on the tool housing, the distance element 14 protrudes through the first opening 31, and the displacement element 12 protrudes through the second opening 32.
[0070] exist Figure 1 In the embodiment, the downhole tool string 1 comprises two second tool sections 22, namely one on each side of the first tool section, so that the operating machine tool 10 in the first tool section is stabilized from each end, even further stabilizing the drilling process. Figure 1 A downhole system 100 is shown, which includes a downhole tool string and a driving unit 30 such as a downhole tractor, which is used to propel the downhole tool string 1 forward in the well. The downhole system 100 is connected to a cable 44 and powered by the cable 44.
[0071] exist Figure 3 In the embodiment of the present invention, the displacement element 12 and the distance element 14 can protrude from the outer surface by being displaced radially outwards without pivoting around a fixed pivot point as described above. The displacement element and the distance element can protrude from the outer surface because the entire displacement element and the entire distance element are displaceable radially outwards, for example formed as part of a piston moving in a radially extending piston housing.
[0072] like Figure 2AAs shown, the tool body has an outer diameter OD, which may be less than 79 mm, preferably less than 54 mm, i.e., less than 2.125 inches. With a tool outer diameter of less than 54 mm, the clearance is so limited that there is no room for any fixed distance elements 14 on the outer surface, because all the clearance is required to provide sufficient radial extension of the operating processing tool (i.e., the drill bit) to allow it to fully extend to drill all the way through the wall of the production casing.
[0073] Fig. 8A and 8B Shows something like Fig. 6A and 6B Embodiment of the embodiment shown.
[0074] Fig. 8A The retracted position, ie the first position, of the first displacement element 12 and the first distance element 14 is shown. The displacement element 12 and the distance element 14 can be extended by pushing a spindle 41 located inside the tool body 5 along its center axis 7 in the direction of the arrow AR.
[0075] Figure 8B The protruding position of the first displacement element 12 and the first distance element 14 is shown, ie the second position, in which the spindle 41 has been pushed to such an extent that parts of the displacement element 12 and the distance element 14 protrude.
[0076] exist Fig. 8A and 8B In the embodiment, the lengths of the parts 60, 61 of the displacement element 12 and the parts 60, 61 of the distance element 14 are different, so that in the protruding state of the displacement element 12 and the distance element 14, the first length L1 and the second length L2 will become different. In this way, the distance element provides a shorter distance to the wall of the metal well pipe structure than the displacement element. Therefore, the distance element ensures a short distance so that chips from, for example, a drilling operation can be guided away from the drill bit.
[0077] A stroke tool is a tool that provides an axial force, which is used, for example, to displace a mandrel within a tool body, or to provide an axial force to release an operating tool from its engagement with a metal well tubular structure. The stroke tool includes an electric motor for driving a pump. The pump pumps a fluid into a piston housing to move a piston acting therein. The piston is arranged on a stroke shaft. The pump can pump fluid out of the piston housing on one side and simultaneously suck fluid on the other side of the piston.
[0078] "Fluid" or "wellbore fluid" refers to any type of fluid present downhole in an oil or gas well, such as natural gas, petroleum, oil-based mud, crude oil, water, etc. "Gas" refers to any type of gas component present in a well, a completed well, or an open hole, and "oil" refers to any type of oil component, such as crude oil, oil-containing fluids, etc. Gas, oil, and water fluids may therefore each include other elements or substances in addition to gas, oil, and / or water, respectively.
[0079] "Casing", "production casing" or "metal well casing" means any type of pipe, tubing, tubular structure, liner, tubular string, etc. used downhole in connection with the production of oil or natural gas.
[0080] In the event that the tool is not fully submerged in the casing, a downhole tractor may be used to push the tool fully into position in the well. The downhole tractor may have an extendable arm 36 with wheels 35, wherein the wheels contact the inner surface of the casing for advancing the tractor and the tool within the casing. The downhole tractor includes an electric motor 37 that drives a pump 38, which provides pressurized fluid for extending the arm 36 and rotating the wheels 35. A downhole tractor is any type of driven tool capable of pushing or pulling a tool downhole, such as a Well The downhole tool string further comprises a control unit 39 for controlling the tool string according to power and signals from an electric cable 44 .
[0081] Although the invention has been described above in conjunction with preferred embodiments of the invention, it will be obvious to a person skilled in the art that several modifications are conceivable without departing from the invention as defined in the following claims.
Claims
1. A downhole tool string (1) for displacing at least a tool section in a well (2) along a radial direction (R) in a wall (3) of a metal well tubular structure (4), the metal well tubular structure extending along an axial direction (L) perpendicular to the radial direction, the downhole tool string include: - a tool body (5) having an outer surface (6) and a tool center axis (7) along the axial direction, a central plane (P) extending along the center axis and containing the center axis, thereby dividing the tool body into a first body half (8) and a second body half (9); - an operational machining tool (10) for performing a machining operation in the metal well structure, such as drilling a hole (11) in the wall, and capable of protruding from the outer surface of the first body half in a first radial direction (R) relative to the central axis of the tool; as well as a first displacement element (12, 12A) which can extend from an outer surface of the second body half of the tool body for displacing the tool body towards the wall portion so as to arrange the operating working tool close to the wall portion, the first displacement element being telescopic between a retracted position and a protruding position, The downhole tool string further comprises a first distance element (14, 14A), which can extend from the outer surface of the first main body half, and has a retracted position and an extended position. In the extended position of the first distance element, a distance (d) is provided between the outer surface and the wall of the metal well pipe structure.
2. The downhole tool string according to claim 1, in, The distance is less than 10 mm, preferably less than 5 mm.
3. The downhole tool string according to claim 1 or 2, in, The operating processing tool is a drill.
4. The downhole tool string according to claim 1, in, The first displacement element in the protruding position protrudes from the outer surface by a first length (L1), and the first distance element in the protruding position protrudes from the outer surface by a second length (L2), and the first length is longer than the second length.
5. The downhole tool string according to claim 1 or 2, in, The first length is greater than 200% of the second length, preferably greater than 300% of the second length, more preferably greater than 400% of the second length, even more preferably greater than 500% of the second length.
6. A downhole tool string according to any one of the preceding claims, in, Before the machining operation begins, the operative machining tool in the extended position has a third length (L3), the second length being less than 50% of the third length.
7. A downhole tool string according to any one of the preceding claims, in, Before the machining operation begins, the operating machining tool in the initial protruding position has a fourth length (L4) that is equal to or shorter than the second length.
8. A downhole tool string according to any one of the preceding claims, in, The first distance element is arranged along the circumference (15) of the tool body at an angle (α) of 0° to ±90° to the operating machining tool, preferably at an angle of 5° to ±45° to the operating machining tool.
9. A downhole tool string according to any one of the preceding claims, in, The first displacement element and the first distance element can be protruded by the same axial displacement in the tool body.
10. A downhole tool string according to any one of the preceding claims, in, The first displacement element and the first distance element can be protruded by means of hydraulic force.
11. A downhole tool string according to any one of the preceding claims, in, The first displacement element and the first distance element can be protruded by means of a piston (16) inside the tool body.
12. The downhole tool string according to any one of claims 1 to 7, in, The first displacement element and the first distance element can protrude by means of a shaft (17) or a wedge (18) inside the tool body.
13. The downhole tool string according to any of the preceding claims further comprises a second displacement element (12B), which protrudes from the second body half and is arranged along the circumference (15) of the tool body to form an angle (V) of 0° to 120° with the first displacement element, preferably an angle of 5° to 120° with the first displacement element, and more preferably an angle of 20° to 120° with the first displacement element.
14. The downhole tool string according to any of the preceding claims further comprises a second distance element (14B), which protrudes from the first main body half and is arranged at an angle (β) of 0° to 120° with the first distance element along the circumference of the tool body, preferably at an angle of 5° to 120° with the first distance element, and more preferably at an angle of 20° to 120° with the first distance element.
15. A downhole tool string according to any one of the preceding claims, in, The displacement element and the distance element can protrude from the outer surface by pivoting about their respective pivot points (19, 20).
16. The downhole tool string according to any one of claims 1 to 14, in, The displacement element and the distance element can protrude from the outer surface by being displaced radially outwards.
17. A downhole system (100), comprising a driving unit (30) and a downhole tool string according to any one of claims 1-16, wherein the driving unit is used to propel the downhole tool string forward in a well, and the driving unit is, for example, a downhole tractor.