A variable diameter stabilizer

Abstract

The present application provides a variable diameter stabilizer, comprising: a shell; a centralizer movably arranged on the outer wall of the shell; a mandrel axially slidingly arranged in the shell; a spring sleeved in the shell, the two ends of the spring respectively abutting with the mandrel and the shell; wherein a protrusion is arranged on the outer wall of the mandrel corresponding to the centralizer, the protrusion is configured to push the centralizer radially when the mandrel moves towards the shell, thereby expanding the outer diameter of the stabilizer. The present application drives the protrusion to move by the radially movable mandrel, pushes the centralizer to produce radial movement, changes the outer diameter of the stabilizer, and thus achieves the purpose of variable diameter. In addition, the present application is provided with a guide slope on the centralizer, the protrusion cooperates with the guide slope, and the stepless variable diameter of the stabilizer can be realized. The present application has the characteristics of variable outer diameter and drilling pressure control outer diameter, can adapt to different wellbore sizes, and the variable diameter is stable and reliable, which can effectively improve the drilling efficiency.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas drilling technology, specifically, it relates to a variable diameter stabilizer. Background Technology

[0002] During oil and gas well drilling, due to the difference between drill bit and drill string dimensions and wellbore dimensions, problems such as excessive wellbore inclination in vertical wells and difficulty in controlling the trajectory of deviated and horizontal wells often occur, especially when the drilled formation has a large dip angle, significant variations in formation lithology, uneven drilling feed, or a large wellbore enlargement rate. To avoid this, the drill string assembly is usually optimized. The most direct approach is to add a centralizer to the drill string assembly to increase its rigidity and stability. However, existing drill bit stabilizers are mostly fixed-diameter or hydraulically variable-diameter centralizers. Both types of stabilizers have significant drawbacks:

[0003] For centralizers with fixed outer diameters, the centralizing effect is unstable due to changes in the wellbore enlargement rate. In soft formations, the outer diameter of the centralizer can easily result in an excessive gap between itself and the wellbore, causing the drill bit axis to deviate from the drill string axis and affecting the drilling effect.

[0004] Hydraulic variable-diameter centralizers typically achieve a stepped change in outer diameter using variations in the displacement of a surface mud pump, usually in 2-3 stages. During drilling, many factors influence the displacement, making it difficult to accurately control the diameter change of the hydraulic variable-diameter centralizer on the surface. Furthermore, the complex structure of hydraulic variable-diameter centralizers hinders subsequent equipment maintenance. Summary of the Invention

[0005] To address the technical problems described above, this invention aims to provide a variable diameter stabilizer that can stabilize and straighten the drill string during the drilling process.

[0006] According to the present invention, a variable diameter stabilizer is provided, comprising: a housing; a straightening block movably disposed on the outer wall of the housing; a mandrel axially slidably disposed within the housing; and a spring sleeved within the housing, the two ends of the spring respectively abutting against the mandrel and the housing; wherein, a protrusion is provided on the outer wall of the mandrel corresponding to the straightening block, the protrusion being configured such that when the mandrel moves in the direction of the housing, the protrusion can radially push the straightening block, thereby expanding the outer diameter of the stabilizer.

[0007] In one embodiment, a guide ramp is provided at the position where the straightening block contacts the protrusion.

[0008] In one embodiment, the number of straightening blocks is three, and three mounting slots for mounting the straightening blocks are evenly arranged along the circumference of the housing.

[0009] In one embodiment, the straightening block is rotatably connected to the housing, and the rotation axis of the straightening block is parallel to the central axis of the housing.

[0010] In one embodiment, a pivot is provided at the edge of the straightening block, and the straightening block is rotatably connected to the housing via the pivot.

[0011] In one embodiment, the housing includes an outer shell and an upper pressure cover disposed at the top of the outer shell, the straightening block is located between the upper pressure cover and the outer shell, and mounting holes for mounting the rotating shaft are provided on both the upper pressure cover and the outer shell.

[0012] In one embodiment, the mandrel includes a first mandrel and a second mandrel, the outer diameter of the second mandrel being larger than the outer diameter of the first mandrel, and a limiting surface for abutting the end face of the second mandrel is provided on the inner wall of the upper pressure cover.

[0013] In one embodiment, the outer wall of the second mandrel is a regular hexagon, and the inner wall of the housing is set to an inner hexagon corresponding to the second mandrel.

[0014] In one embodiment, a central shaft is provided inside the housing along its central axis, a mandrel is sleeved on the central shaft, an annular space exists between the second mandrel and the central shaft, and the spring is located within the annular space.

[0015] In one embodiment, an upper connector is provided at the top of the mandrel, a lower connector is provided at the bottom of the housing, and a spiral flow channel is provided on the outer wall of the housing.

[0016] Compared with the prior art, the advantages of this application are:

[0017] This invention addresses the problem of unstable centering effects in existing fixed-size drill bit stabilizers and hydraulic variable-diameter stabilizers by providing a mechanical variable-diameter stabilizer. A radially movable mandrel drives a protrusion to move, pushing the centering block to generate radial movement and changing the stabilizer's outer diameter, thus achieving diameter variation. Furthermore, the centering block of this invention is equipped with a guide ramp; the protrusion cooperates with the guide ramp to achieve stepless diameter variation of the stabilizer. This invention features variable outer diameter and drill pressure-controlled outer diameter, adapting to different wellbore sizes, and providing stable and reliable diameter variation, effectively improving drilling efficiency. Attached Figure Description

[0018] The invention will now be described with reference to the accompanying drawings.

[0019] Figure 1 A schematic diagram of an embodiment of the variable diameter stabilizer in its initial state according to the present invention is shown;

[0020] Figure 2 A schematic diagram of one embodiment of the variable diameter stabilizer according to the present invention under pressure is shown;

[0021] Figure 3 A schematic diagram of an embodiment of the housing according to the present invention is shown;

[0022] Figure 4 A schematic diagram of one embodiment of the upper pressure cap according to the present invention is shown;

[0023] Figure 5 A schematic diagram of one embodiment of the mandrel according to the present invention is shown;

[0024] Figure 6 A schematic diagram of one embodiment of the straightening block according to the present invention is shown;

[0025] Figure 7 A three-dimensional structural schematic diagram of the straightening block of the present invention is shown.

[0026] In the diagram: 1. Upper connector; 2. Mandrel; 201. First mandrel; 202. Second mandrel; 203. Inner hole; 204. Protrusion; 3. Upper pressure cap; 301. Second internal hexagonal joint; 302. Bolt hole; 303. Second spiral flow channel; 304. Limiting surface; 4. Spring; 5. Straightening block; 501. Rotating shaft; 502. Guide slope; 6. Outer shell; 601. Lower connector; 602. Mounting hole; 603. First internal hexagonal joint; 604. Central shaft; 605. Threaded hole; 606. First spiral flow channel; 607. Mounting groove; 7. Housing.

[0027] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0028] The invention will now be described with reference to the accompanying drawings.

[0029] In this application, it should be noted that the direction near the upper connector 1 according to the present invention is described as "upper", "front" or similar terms, and the direction near the lower connector 601 is described as "lower", "rear" or similar terms.

[0030] Figure 1 A schematic diagram of an embodiment of the variable diameter stabilizer 100 according to the present invention in its initial state is shown. Figure 1 As shown, the variable diameter stabilizer 100 includes a housing 7, a straightening block 5, and a spindle 2. The straightening block 5 is disposed through-hole on the outer wall of the housing 7. The spindle 2 is axially slidably disposed inside the housing 7, and the spindle 2 can contact the straightening block 5. Specifically, as shown... Figure 2 and Figure 5 As shown, a protrusion 204 is provided on the outer wall of the mandrel 2. Figure 1 In the middle, the variable diameter stabilizer 100 is not under pressure, the spindle 2 is in the initial position, and the protrusion 204 at this time ( Figure 1 (Not shown in the image) It is not in contact with the straightening block 5, and the variable diameter stabilizer 100 is in its minimum outer diameter state. Figure 2 During operation, the variable diameter stabilizer 100 is compressed, causing the spindle 2 to move towards the housing 7. At this time, the protrusion 204 abuts against the straightening block 5, pushing it radially and causing it to extend outward, thus changing the outer diameter of the stabilizer. A spring 4 is also fitted inside the housing 7, with its central axis coinciding with the central axis of the housing 7. The upper end of the spring 4 abuts against the spindle 2, and the lower end abuts against the housing 7. With this configuration, the spindle 2 will only move towards the housing 7 when the pressure on the variable diameter stabilizer 100 exceeds the spring force. Therefore, by using springs 4 with different stiffnesses, the purpose of changing the stabilizer's diameter can be achieved under different drilling pressures.

[0031] In a preferred embodiment, such as Figure 6 and Figure 7 As shown, a guide slope 502 is provided at the position where the straightening block 5 contacts the protrusion 204. In this embodiment, the depth of the guide slope 502 gradually decreases along the direction from the spindle 2 to the housing 7. The protrusion 204 moves within the guide slope 502 under the drive of the spindle 2, and the protrusion 204 controls the outward extension distance of the straightening block 5 through the guide slope 502. With this setting, the greater the displacement of the protrusion 204 towards the housing 7 driven by the spindle 2, the longer the outward extension distance of the straightening block 5. Thus, the extension distance of the straightening block 5 can be controlled by controlling the drilling pressure in conjunction with springs 4 of different stiffnesses, achieving stepless diameter change of the variable diameter stabilizer 100. At the same time, controlling the outer diameter of the stabilizer by drilling pressure is simpler in structure and easier to control compared to the hydraulic variable diameter stabilizer in the prior art.

[0032] like Figure 3 and Figure 4 As shown, in one specific embodiment, the housing 7 includes an outer shell 6 and an upper cover 3, with the upper cover 3 disposed at the top of the outer shell 6. A bolt hole 302 is provided through the upper cover 3 along its axis, and a threaded hole 605 is provided on the outer shell 6 at the corresponding position of the bolt hole 302. The upper cover 3 and the outer shell 6 are connected to each other by bolts. A mounting groove 607 is provided on the outer wall of the outer shell 6, and the straightening block 5 is located within the mounting groove 607. In this configuration, the straightening block 5 is mounted on the outer shell 6 via the upper cover 3, facilitating installation and subsequent disassembly and maintenance.

[0033] like Figure 5As shown, in a specific embodiment, the mandrel 2 includes a first mandrel 201 and a second mandrel 202. The first mandrel 201 is used to connect to the upper connector 1, while the second mandrel 202 is sleeved inside the housing 7 and can be used to transmit torque to the housing 7. To enable the mandrel 2 to transmit torque to the housing 7, the outer wall of the second mandrel 202 is configured as a regular hexagon. Correspondingly, the portion of the housing 7 for axial movement of the second mandrel 202 is configured as an internal hexagon that mates with the outer wall of the second mandrel 202. Figure 3 and Figure 4 As shown, a first hexagonal 603 is provided on the inner wall of the outer shell 6, and a second hexagonal 301 is provided on the inner wall of the upper cover 3. After the outer shell 6 is connected to the upper cover 3, the first hexagonal 603 and the second hexagonal 301 constitute the overall hexagonal shape of the shell 7.

[0034] In this embodiment, since the inner wall of the outer shell 6 is constructed in an inner hexagonal shape, in order to make full use of space and make the structure of the invention compact, the number of straightening blocks 5 is set to three, and three mounting slots 607 for mounting the straightening blocks 5 are evenly arranged along the circumference of the outer shell 7. Similarly, three protrusions 204 are evenly distributed circumferentially on the second spindle 202, which respectively cooperate with the three straightening blocks 5. Specifically, the position of one straightening block 5 occupies exactly one plane forming the inner hexagon, and the protrusions 204 are all arranged on the plane forming the regular hexagon of the second spindle 202. With this arrangement, the parts are easy to process, easy to install, and the structure is compact.

[0035] In one specific embodiment, three spiral flow channels are evenly distributed circumferentially along the shell 7. Three first spiral flow channels 606 are evenly distributed circumferentially on the outer wall of the outer shell 6, and three second spiral flow channels 303 are evenly distributed circumferentially on the outer wall of the upper pressure cover 3. After the upper pressure cover 3 is connected to the outer shell 6, each first spiral flow channel 606 and each second spiral flow channel 303 corresponds to and connects with each other, forming the overall spiral flow channel of the shell 7. Specifically, a spiral flow channel is provided between each pair of adjacent mounting slots 607, making full use of space and ensuring that they do not interfere with each other.

[0036] In a preferred embodiment, the straightening block 5 is rotatably connected to the housing 7, and the rotation axis of the straightening block 5 is parallel to the central axis of the housing 7. Since the protrusion 204 is in point contact with the straightening block 5, this arrangement ensures that after the straightening block 5 rotates along the rotation axis, the portion extending outward to form the maximum outer diameter of the variable diameter stabilizer 100 is a line segment parallel to the axis. During use, the rotation direction of the straightening block 5 when it extends outward is consistent with the rotation direction of the drill bit during drilling, which has little impact on the drilling of the drill bit, thereby improving the working stability of the variable diameter stabilizer 100.

[0037] like Figure 6As shown, in a specific embodiment, a pivot 501 is provided at the edge of the straightening block 5. The straightening block 5 is rotatably connected to the housing 7 via the pivot 501. The pivot 501 is positioned as close as possible to the side of the straightening block 5 to prevent one side of the straightening block 5 from flipping outward while the other side flips inward, thus avoiding interference with internal components.

[0038] like Figure 1 and Figure 3 As shown, in this embodiment, the upper cover 3 is provided with a mounting hole 602 for mounting the rotating shaft 501, and the outer casing 6 is provided with another mounting hole 602 for mounting the rotating shaft 501.

[0039] like Figure 1 and Figure 5 As shown, the outer diameter of the second spindle 202 is larger than the outer diameter of the first spindle 201, and a limiting surface 304 for abutting the end face of the second spindle 202 is provided on the inner wall of the upper pressure cover 3. This arrangement prevents the spindle 2 from detaching from the housing 7.

[0040] In one specific embodiment, a central shaft 604 is disposed inside the outer casing 6 along its central axis, and the interior of the central shaft 604 is a hollow structure. A space exists between the central shaft 604 and the inner wall of the outer casing 6 to accommodate a mandrel 2. The mandrel 2 is sleeved on the central shaft 604, wherein the inner diameter of the first mandrel 201 is equal to the outer diameter of the central shaft 604, and the inner diameter of the second mandrel 202 is larger than the outer diameter of the central shaft 604. An annular space exists between the second mandrel 202 and the central shaft 604, and the spring 4 is located within this annular space. This arrangement prevents the spring 4 from contacting the centering block 5 due to accidental deformation during compression, thereby improving the operational stability and reliability of the invention.

[0041] According to the present invention, a lower connector 601 is provided at the bottom of the housing 7.

[0042] It is easy to understand that the upper connector 1 and the lower connector 601 can be connected to other downhole tools such as drill bits or screws in drill strings. This is existing technology and will not be described in detail here.

[0043] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0044] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0046] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A variable diameter stabilizer, characterized in that, include: Shell (7); Multiple straightening blocks (5) are movably disposed on the outer wall of the housing (7), and the straightening blocks (5) are evenly distributed along the circumference of the housing (7); A spindle (2) is axially slidably disposed within the housing (7); A spring (4) is fitted inside the housing (7), and the two ends of the spring (4) abut against the spindle (2) and the housing (7) respectively; In this embodiment, a protrusion (204) is provided on the outer wall of the mandrel (2) corresponding to each of the straightening blocks (5). The protrusion (204) is configured such that when the mandrel (2) moves toward the housing (7), the protrusion (204) can radially push the straightening block (5), thereby expanding the outer diameter of the stabilizer. The straightening block (5) is rotatably connected to the housing (7). The rotation axis of the straightening block (5) is parallel to the central axis of the housing (7). A rotating shaft (501) is provided at the edge of the straightening block (5). The straightening block (5) is rotatably connected to the housing (7) through the rotating shaft (501). The housing (7) includes an outer shell (6) and an upper pressure cover (3) disposed at the top of the outer shell (6). The straightening block (5) is located between the upper pressure cover (3) and the outer shell (6). Mounting holes (602) for mounting the rotating shaft (501) are provided on both the upper pressure cover (3) and the outer shell (6). The mandrel (2) includes a first mandrel (201) and a second mandrel (202). The outer diameter of the second mandrel (202) is larger than the outer diameter of the first mandrel (201). A limiting surface (304) for abutting the end face of the second mandrel (202) is provided on the inner wall of the upper pressure cover (3). The outer wall of the second mandrel (202) is a regular hexagon. The inner wall of the housing (7) is set as an inner hexagon corresponding to the second mandrel (202). A central shaft (604) is provided inside the outer casing (6) along its central axis. The spindle (2) is sleeved on the central shaft (604). There is an annular space between the second spindle (202) and the central shaft (604). The spring (4) is located in the annular space.

2. The variable diameter stabilizer according to claim 1, characterized in that, A guide slope (502) is provided at the position where the straightening block (5) contacts the protrusion (204).

3. The variable diameter stabilizer according to claim 2, characterized in that, The number of the straightening blocks (5) is three, and three mounting slots (607) for mounting the straightening blocks (5) are evenly arranged along the circumference of the housing (7).

4. The variable diameter stabilizer according to any one of claims 1 to 3, characterized in that, An upper connector (1) is provided at the top of the mandrel (2), a lower connector (601) is provided at the bottom of the housing (7), and a spiral flow channel is provided on the outer wall of the housing (7).

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