A downhole centralizer

Abstract

The present invention discloses a downhole centralizer, which relates to the field of drilling and exploration technology. The device comprises a rod body, a casing, and a slider. One end of the rod body is connected to a drill pipe, and the other end is connected to a drilling tool. The casing is sleeved outside the rod body, and the rod body can rotate about the central axis of the casing. The casing is fixedly connected to the rod body in the axial direction. The slider is slidably connected to the casing. One side of the slider protrudes from the outer side of the casing. The slider can slide toward the end of the rod body connected to the drilling tool and gradually approach the central axis of the rod body. The downhole centralizer can prevent the normal operation of the drill pipe caused by falling blocks from being blocked and affected by the falling blocks, and can also facilitate the removal of the blockage caused by falling blocks.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling exploration, in particular to a downhole centralizer. Background Art

[0002] Drilling mainly relies on rotary equipment such as a turntable or top drive on the surface to drive the drill pipe and the drill bit at the bottom of the drill pipe to rotate together. The drill bit in a high-speed rotating state will generate a certain shear force and impact force on the underground rock under a certain drilling pressure, thereby breaking the rock and carrying the rock cuttings at the bottom of the well to the surface through the continuous circulation of high-speed mud. Among them, the downhole centralizer is an important tool used to stabilize the drilling direction and prevent changes in well inclination. It is connected to the drill pipe close to the drill bit, or connected between the drill pipe and the drill bit. During geological exploration operations, the centralizer plays the role of maintaining the diameter and trimming the well wall. It can make the well wall smoother and flatter, and the quality of the wellbore is better. However, most of the downhole centralizers currently used are fixedly connected to the drill pipe and drill bit and rotate synchronously. When the open hole section above the centralizer collapses and debris falls, large debris will fall between the wellbore wall and the centralizer, causing the drill string to get stuck, preventing the drill pipe and drill string from rotating, and leading to accidents such as pump blocking. Furthermore, when debris is stuck between the centralizer and the wellbore wall, it is difficult to lift the drill string and drill pipe, and it is also relatively difficult to remove the blockage. Therefore, there is an urgent need for a downhole centralizer that can prevent debris from getting stuck and affecting the normal operation of the drill string and drill pipe, and that can easily remove the blockage. Summary of the Invention

[0003] The purpose of the present invention is to provide a downhole centralizer to solve the problems existing in the above-mentioned prior art, which can prevent the falling blocks from blocking and affecting the normal operation of the drill pipe, and is also convenient for removing the blocking of the falling blocks.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a downhole centralizer, comprising: a rod body, a casing and a slider, wherein one end of the rod body is used to be connected to a drill pipe, and the other end is used to be connected to a drilling tool, the casing is sleeved outside the rod body, the rod body can rotate around the central axis of the casing, the casing is fixedly connected to the rod body in the axial direction, the slider is slidably connected to the casing, one side of the slider protrudes from the outer side surface of the casing, and the slider can slide toward the end of the rod body used to be connected to the drilling tool and gradually approach the central axis of the rod body.

[0006] Preferably, the rod body includes an upper joint, a core tube and a lower joint that are coaxially arranged and connected at their ends in sequence, the end of the upper joint away from the core tube is used for detachable connection with the drill pipe, the end of the lower joint away from the core tube is used for detachable connection with the drill tool, and the casing is sleeved outside the core tube.

[0007] Preferably, the sleeve is provided with a plurality of slides extending axially along the sleeve, and the plurality of slides are arranged in sequence along the circumference of the sleeve, one end of the slide close to the upper joint is the first end, and the other end is the second end, and the slide gradually approaches the central axis of the sleeve from the first end to the second end, and the slider is slidably connected in each of the slides.

[0008] Preferably, the side surface of each slider away from the core tube is a partial cylindrical surface, and the axis of each cylindrical surface coincides with the central axis of the sleeve.

[0009] Preferably, an elastic element is further included, and the sleeve located at the second end has a limiting portion, one end of the elastic element is connected to the limiting portion, and the other end is connected to the slider, and the slider can move along the slide toward the second end and compress the elastic element, and the elastic element can rebound from the compressed state and drive the slider to move toward the first end.

[0010] Preferably, it also includes a limit pin, a limit hole is provided on the slider, the side of the slider close to the bottom of the slide is the first side, the side of the slider away from the bottom of the slide is the second side, the limit through hole connects the first side and the second side, the limit hole is a strip hole, the limit hole extends along a straight line parallel to the axial direction of the rod body, one end of the limit pin is fixedly connected to the bottom of the slide, the limit pin forms a sliding connection with the limit hole, the elastic element can be extended to make the slider move, and make the limit pin rest on the inner wall of the limit hole close to the second end.

[0011] Preferably, the two side surfaces of the slider close to the inner wall of the slide are the third side and the fourth side respectively, and the third side and the fourth side gradually approach each other from the bottom to the top of the slide, and the shapes of the two inner walls of the slide match the shapes of the third side and the fourth side.

[0012] Preferably, outer side surfaces of the upper joint, the sleeve and the lower joint are all located on the same cylindrical surface.

[0013] Preferably, it further comprises a first bearing and a second bearing, wherein the inner rings of the first bearing and the second bearing are fixedly sleeved on both ends of the core tube, and the outer rings of the first bearing and the second bearing are fixedly connected to the inner side walls at both ends of the sleeve.

[0014] Compared with the prior art, the present invention has achieved the following technical effects:

[0015] The downhole centralizer provided by the present invention has a casing rotatably sleeved outside the rod body, and one side of the slider protrudes from the side of the casing. The falling block will be stuck between the side of the slider protruding from the casing and the well wall. At this time, the casing is blocked and cannot rotate, while the rod body can rotate relative to the casing under the drive of the drill rod, and the drill tool and the drill rod can also operate normally. When it is necessary to release the blocking of the falling block, it is only necessary to lift the drill rod and move the centralizer upward. The slider on the casing can move relative to the casing toward the position of the drill tool and gradually approach the central axis of the rod body. The distance between the slider and the well wall gradually increases, and the falling block has space to move and can directly fall to the bottom of the well, thereby releasing the blocking of the falling block. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A front view of the downhole centralizer provided by the present invention;

[0018] Figure 2 for Figure 1 The internal structure of the downhole centralizer after removing the casing, slider and elastic element;

[0019] Figure 3 A three-dimensional structural diagram of a sliding block in a downhole centralizer provided by the present invention;

[0020] In the figure: 1-rod body, 11-upper joint, 12-core tube, 13-lower joint, 2-sleeve, 21-slideway, 211-first end, 212-second end, 3-slider, 31-first side, 32-second side, 33-third side, 34-fourth side, 35-limiting hole, 36-support surface, 4-limiting pin, 5-elastic element, 6-first bearing, 7-second bearing. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] The purpose of the present invention is to provide a downhole centralizer to solve the problems existing in the above-mentioned prior art, which can prevent the falling blocks from blocking and affecting the normal operation of the drill pipe, and is also convenient for removing the blocking of the falling blocks.

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The present invention provides a downhole centralizer, such as Figure 1-3 As shown, it includes: a rod body 1, a sleeve 2 and a slider 3. One end of the rod body 1 is used to connect with the drill pipe, and the other end is used to connect with the drilling tool. The sleeve 2 is sleeved on the outside of the rod body 1. The rod body 1 can rotate around the central axis of the sleeve 2. The sleeve 2 is fixedly connected in the axial direction of the rod body 1. The slider 3 is slidably connected to the sleeve 2. One side of the slider 3 protrudes from the outer side of the sleeve 2. The slider 3 can slide toward the end of the rod body 1 for connecting with the drilling tool and gradually approach the central axis of the rod body 1.

[0025] When the drill bit is pulled out of the well, the drill bit 2 is pushed out of the wellbore 2 and the drill bit 2 is lowered to the wellbore 2, so that the drill bit 2 and the drill bit 2 can be lowered to the wellbore 2.

[0026] To facilitate installation and disassembly, in a preferred embodiment of this embodiment, the rod body 1 includes an upper joint 11, a core tube 12, and a lower joint 13, which are coaxially arranged and connected at their ends in sequence. The end of the upper joint 11 away from the core tube 12 is used for detachable connection with the drill pipe, and the end of the lower joint 13 away from the core tube 12 is used for detachable connection with the drilling tool. The casing 2 is sleeved outside the core tube 12. The upper joint 11 and the core tube 12 can be, but are not limited to, threadedly connected, and the core tube 12 and the lower joint 13 can be, but are not limited to, threadedly connected.

[0027] In a preferred embodiment of this embodiment, the casing 2 is provided with a plurality of slideways 21 extending axially along the casing 2. The plurality of slideways 21 are sequentially arranged along the circumference of the casing 2. The end of the slideway 21 closest to the upper connector 11 is a first end 211, and the other end is a second end 212. The slideway 21 gradually approaches the central axis of the casing 2 from the first end 211 to the second end 212. A slider 3 is slidably connected to each slideway 21. When the slider 3 is at the first end 211, the distance between the side of the slider 3 and the well wall is small, and the falling block is stuck between the slider and the well wall, leaving no room for the falling block to move. When it is necessary to lift and release the falling block, the slider 3 moves along the slideway 21 toward the second end 212, and the distance between the side of the slider 3 and the well wall increases, allowing the falling block to fall through the gap between the slider 3 and the well wall.

[0028] In a preferred embodiment of this embodiment, the side surfaces of each slider 3 away from the core barrel 12 are partially cylindrical, and the axis of each cylindrical surface coincides with the central axis of the casing 2. The arc-shaped side surfaces of the slider 3 stabilize the drilling direction and prevent changes in well inclination. At the same time, compared to the contact area between a flat surface and the drop block, the arc surface has a smaller contact area with the drop block, making it easier to remove the block from being stuck.

[0029] In a preferred embodiment of this embodiment, the downhole centralizer provided by the present invention further includes an elastic element 5. A limiting portion is provided on the casing 2 at the second end 212. One end of the elastic element 5 is connected to the limiting portion, and the other end is connected to the slider 3. The slider 3 can move along the slide 21 toward the second end 212 and compress the elastic element 5. The elastic element 5 can rebound from its compressed state and drive the slider 3 to move toward the first end 211. When the drill tool is lifted, the slider 3 moves toward the second end 212 and compresses the elastic element 5. When the block falls to the bottom of the well and the blockage is released, the slider 3 can move toward the first end 211 under the rebound action of the elastic element 5 and automatically reset underground. This eliminates the need to lift the centralizer out of the well and manually reset it, making it more convenient to use. Among them, a first mounting inclined hole is provided on the limiting portion, and the extension direction of the first mounting inclined hole is parallel to the extension direction of the slide 21. A second mounting inclined hole is provided on the side of the slider 3 opposite to the limiting portion, and the extension direction of the second mounting inclined hole is parallel to the extension direction of the slide 21. The elastic element 5 is preferably a spring, and one end of the elastic element 5 is fixedly installed in the first mounting inclined hole, and the other end is fixedly installed in the second mounting inclined hole.

[0030] In a preferred embodiment of this embodiment, the downhole centralizer provided by the present invention further includes a limit pin 4. A limit hole 35 is provided on the slider 3. The side of the slider 3 near the bottom of the slideway 21 is a first side 31, and the side of the slider 3 away from the bottom of the slideway 21 is a second side 32. The limit hole connects the first side 31 and the second side 32. The limit hole 35 is a strip-shaped hole extending along a straight line parallel to the axial direction of the rod body 1. One end of the limit pin 4 is fixedly connected to the bottom of the slideway 21. The limit pin 4 forms a sliding connection with the limit hole 35. The elastic element 5 can extend to move the slider 3 and cause the limit pin 4 to abut against the inner wall of the limit hole 35 near the second end 212. When the slider 3 moves to the first end 211, the elastic element 5 still has a rebound ability, and the limit pin 4 can abut against the inner wall of the limit hole 35 near the second end 212, thereby preventing the slider 3 from separating from the slideway 21 due to the rebound action of the elastic element 5. The limiting hole 35 further has an annular supporting surface 36 on its circumference. When the slider 3 slides close to the first end 211 , the nail cap of the limiting pin 4 can contact the supporting surface 36 .

[0031] In a preferred embodiment of this embodiment, the two side surfaces of the slider 3 close to the inner side wall of the slideway 21 are respectively the third side 33 and the fourth side 34, and the third side 33 and the fourth side 34 gradually approach each other from the bottom to the top of the slideway 21 ( Figure 3 (The third side 33 and the fourth side 34 are shown as being parallel in the figure) and the shapes of the two inner side walls of the slideway 21 match those of the third side 33 and the fourth side 34. The third side 33 and the fourth side 34, which gradually approach each other from the bottom to the top of the slideway 21, can cooperate with the two opposite side surfaces of the slideway 21, thereby limiting the slider 3 and preventing it from falling off the slideway 21.

[0032] In a preferred embodiment of this embodiment, the outer side surfaces of the upper joint 11, the sleeve 2, and the lower joint 13 are all located on the same cylindrical surface. The side surfaces of the upper joint 11, the sleeve 2, and the lower joint 13 being located on the same cylindrical surface can improve the integrity of the centralizer.

[0033] In a preferred embodiment of this embodiment, the downhole centralizer provided by the present invention further includes a first bearing 6 and a second bearing 7. The outer rings of the first bearing 6 and the second bearing 7 are fixedly mounted on both ends of the core tube 12, and the inner rings of the first bearing 6 and the second bearing 7 are fixedly connected to the inner sidewalls of the two ends of the casing 2. Connecting the core tube 12 and the casing 2 via the first bearing 6 and the second bearing 7 ensures that the core tube 12 and the casing 2 can rotate relative to each other while improving the reliability of the connection. The first bearing 6 and the second bearing 7 are preferably deep groove ball bearings. The number of first bearings 6 and second bearings 7 can be set as needed. For example, two first bearings 6 and two second bearings 7 can be provided at each end of the core tube 12, as long as the connection requirements of the casing 2 and the core tube 12 are met.

[0034] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A downhole centralizer, characterized by: include: The rod body, the sleeve, the slider, the elastic element and the limit pin, one end of the rod body is used to connect with the drill pipe, and the other end is used to connect with the drilling tool, the sleeve is sleeved outside the rod body, the rod body can rotate around the central axis of the sleeve, the sleeve is fixedly connected in the axial direction of the rod body, and the sleeve is provided with a plurality of slideways extending along the axial direction of the sleeve, the slider is slidably connected to the sleeve, one side of the slider protrudes from the outer side surface of the sleeve, the slider can slide toward the end of the rod body for connecting with the drilling tool and gradually approach the central axis of the rod body, the rod body includes an upper joint, a core tube and a lower joint which are coaxially arranged and connected in sequence at the ends The cam is connected to the bottom of the slide by a threaded rod, and the cam has a first end and a second end, the cam being connected to the bottom of the slide by a threaded rod.

2. The downhole centralizer according to claim 1, characterized in that: The end of the upper joint away from the core pipe is used for detachable connection with the drill rod, the end of the lower joint away from the core pipe is used for detachable connection with the drilling tool, and the casing is sleeved outside the core pipe.

3. The downhole centralizer according to claim 2, characterized in that: The plurality of slideways are sequentially arranged along the circumference of the sleeve, and the slideways gradually approach the central axis of the sleeve from the first end to the second end, and the slider is slidably connected to each of the slideways.

4. The downhole centralizer according to claim 3, characterized in that: The side surfaces of each slider away from the core tube are all partial cylindrical surfaces, and the axes of each cylindrical surface coincide with the central axis of the sleeve.

5. The downhole centralizer according to claim 3, characterized in that: The sleeve at the second end has a limiting portion, one end of the elastic element is connected to the limiting portion, and the other end is connected to the slider. The slider can move along the slide toward the second end and compress the elastic element. The elastic element can rebound from the compressed state and drive the slider to move toward the first end.

6. The downhole centralizer according to claim 3, characterized in that: The two side surfaces of the slider close to the inner wall of the slide are respectively the third side and the fourth side, and the third side and the fourth side gradually approach each other from the bottom to the top of the slide, and the shapes of the two inner walls of the slide match the shapes of the third side and the fourth side.

7. The downhole centralizer according to claim 2, characterized in that: The outer side surfaces of the upper joint, the sleeve and the lower joint are all located on the same cylindrical surface.

8. The downhole centralizer according to claim 2, characterized in that: It also includes a first bearing and a second bearing, wherein the inner rings of the first bearing and the second bearing are fixedly sleeved on both ends of the core tube, and the outer rings of the first bearing and the second bearing are fixedly connected to the inner side walls of both ends of the sleeve.

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