An adjustable bending joint

Abstract

The present invention discloses an adjustable bending joint, which relates to the technical field of drilling tools and mainly includes an outer sleeve, a torque transmission shaft and a limiting member. The outer sleeve is connected to the drill pipe, and the inner part of the outer sleeve has a through hole inclined relative to the drill pipe. The first end of the torque transmission shaft is arranged in the through hole, and the second end extends out of the outer sleeve and is used for connecting the drill bit. Moreover, the first end of the torque transmission shaft is slidably connected to the outer sleeve through a sliding limiting mechanism, so that the torque transmission shaft is axially slidably connected to the outer sleeve and the circumferential rotation of the torque transmission shaft is restricted. The limiting member is arranged in the through hole and is used for abutting against the first end of the torque transmission shaft. By adjusting the limiting position of the limiting member, the distance that the second end of the torque transmission shaft extends out of the outer sleeve can be adjusted. The present invention can change the radial offset of the drill bit, thereby changing the build-up rate and the lateral force, and ensuring the effect of directional drilling.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling tools, and particularly to an adjustable bent sub. Background Art

[0002] One trip drilling refers to completing the entire interval or section of drilling with a single bit without pulling out the drill string during drilling. The one trip drilling technology can significantly reduce the number of trips in and out of the well, reduce the consumption of drill bits, thereby greatly improving the mechanical drilling rate, shortening the drilling cycle, and reducing the labor intensity of workers and the drilling operation cost. For the section of a well with a complex trajectory design drilled using a traditional bent housing positive displacement motor (PDM), although drill tools such as the bit and the PDM can basically meet the drilling requirements of one trip drilling. However, due to the fixed bend of the PDM, the offset of the PDM relative to the vertical well axis is fixed, resulting in a fixed build rate, and a fixed build rate leads to a fixed lateral force, making it impossible to adjust the build rate downhole to meet the directional operation requirements of the section with a complex trajectory design. Furthermore, in some complex well sections with high requirements for wellbore trajectories, the application of the one trip drilling technology with traditional PDMs for directional drilling is still limited.

[0003] Therefore, an adjustable bent sub is needed, which can gradually change the radial offset of the bit during drilling according to the requirements of directional drilling, thereby changing the build rate and the lateral force to ensure the effect of directional drilling. Summary of the Invention

[0004] The purpose of the present invention is to provide an adjustable bent sub to solve the problems existing in the above prior art, which can change the radial offset of the bit, thereby changing the build rate and the lateral force to ensure the effect of directional drilling.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] The present invention provides an adjustable bent sub, including an outer sleeve, a torque transmission shaft, and a limiting member. The outer sleeve is connected to the drill pipe, and the inner part of the outer sleeve has a through hole inclined relative to the drill pipe. The first end of the torque transmission shaft is arranged in the through hole, and the second end extends out of the outer sleeve and is used to connect the bit. The first end of the torque transmission shaft is slidably connected to the outer sleeve through a sliding limiting mechanism, so that the torque transmission shaft is axially slidably connected to the outer sleeve and the circumferential rotation of the torque transmission shaft is restricted. The limiting member is arranged in the through hole and is used to abut against the first end of the torque transmission shaft. By adjusting the limiting position of the limiting member, the distance that the second end of the torque transmission shaft extends out of the outer sleeve can be adjusted.

[0007] Preferably, the through hole is inclined relative to the outer sleeve, and the outer sleeve is coaxially arranged with the drill pipe.

[0008] Preferably, the limiting member is a limiting screw, which is arranged at one end of the outer sleeve close to the drill pipe, and multiple rows are arranged in sequence along the length direction of the outer sleeve; wherein, the limiting screw extends radially along the through hole, and multiple limiting screws in each row are distributed circumferentially along the through hole, and the limiting screws in the same row are in the same plane, and the limiting screw can be separated from the outer sleeve by stamping of the torque transmission shaft.

[0009] Preferably, the first end of the torque transmission shaft has a tapered hole for accommodating the cut-off limiting screw.

[0010] Preferably, the sliding limiting mechanism includes a spline groove and a spline. The outer sleeve includes a spline sleeve part, and the spline groove is arranged in the spline sleeve part. The spline sleeve is arranged along the length direction of the through hole. The first end of the torque transmission shaft is provided with the spline, and the spline is arranged along the length direction of the torque transmission shaft, and the spline is slidably arranged in the spline groove.

[0011] Preferably, the outer sleeve further includes a smooth part, which is connected to one end of the spline sleeve part far from the drill pipe. The smooth part is provided with a smooth round hole for the torque transmission shaft to pass through. The inner diameter of the smooth round hole is smaller than the diameter of the circumferential surface surrounded by the splines, which can prevent the torque transmission shaft from slipping out of the outer sleeve.

[0012] Preferably, the distance between the limiting screw close to the smooth round hole and the smooth part is greater than the length of the spline, so as to ensure that the spline is located in the spline groove between the smooth part and the limiting screw.

[0013] Preferably, a sealing ring is arranged on the end face of the smooth part of the outer sleeve, and the sealing ring is used for sealing the liquid between the torque transmission shaft and the outer sleeve.

[0014] Preferably, the spline sleeve part is provided with a male thread for threaded connection with the drill pipe connected to the driving device.

[0015] Preferably, the end of the torque transmission shaft connected to the drill bit is provided with a female thread for the drill bit to be connected.

[0016] The present invention has achieved the following technical effects compared with the prior art:

[0017] The outer sleeve of the present invention is connected to the drill pipe, and a through hole inclined relative to the drill pipe is provided inside the outer sleeve. The first end of the torque transmission shaft is arranged in the through hole, and the second end extends out of the outer sleeve and is used to connect the drill bit. The first end of the torque transmission shaft is slidably connected to the outer sleeve through a sliding limiting mechanism, so that the torque transmission shaft is axially slidably connected to the outer sleeve and the circumferential rotation of the torque transmission shaft is restricted. The limiting member is arranged in the through hole and is used to abut against the first end of the torque transmission shaft. By adjusting the limiting position of the limiting member, the distance that the second end of the torque transmission shaft extends out of the outer sleeve can be adjusted, the radial offset of the drill bit can be changed, and then the build-up rate can be changed, the lateral force can be changed, and the effect of directional drilling can be ensured. Brief Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of the adjustable bent sub in the embodiment of the present invention;

[0020] Figure 2 It is a three-dimensional structure diagram of the adjustable bent sub in the embodiment of the present invention.

[0021] In the figure: 1 - outer sleeve; 11 - spline sleeve part; 12 - smooth part; 2 - torque transmission shaft; 21 - the first end of the torque transmission shaft; 22 - the second end of the torque transmission shaft; 3 - limit screw; 4 - spline sleeve; 5 - spline; 6 - spline groove. Detailed Embodiments

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0023] The purpose of the present invention is to provide an adjustable bent sub to solve the problems existing in the prior art, which can change the radial offset of the drill bit, and then change the build-up rate, change the lateral force, and ensure the effect of directional drilling.

[0024] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0025] As Figure 1 - Figure 2As shown in the figure, the present invention provides an adjustable bent sub, which includes an outer sleeve 1, a torque transmission shaft 2 and a limiting member. The outer sleeve 1 is used to connect with a drill pipe, and the inner part of the outer sleeve 1 has a through hole inclined relative to the drill pipe. The first end 21 of the torque transmission shaft is arranged in the through hole, and the second end 22 of the torque transmission shaft extends out of the outer sleeve 1 and is used to connect with a drill bit. Moreover, the first end 21 of the torque transmission shaft is slidably connected with the outer sleeve 1 through a sliding limiting mechanism, so that the torque transmission shaft 2 is axially slidably connected to the outer sleeve 1 and the rotation of the torque transmission shaft 2 in the circumferential direction is restricted. The limiting member is arranged in the through hole and is used to abut against the first end 21 of the torque transmission shaft. The position where the limiting member abuts against the first end 21 of the torque transmission shaft is the limiting position of the limiting member. By adjusting the limiting position of the limiting member, the distance that the second end 22 of the torque transmission shaft extends out of the outer sleeve 1 can be adjusted, the radial offset of the drill bit can be changed, and then the build rate can be changed, the lateral force can be changed, and the effect of directional drilling can be ensured. Specifically explained, the fundamental reason why a directional drilling tool can build a slope is that the drill bit has a lateral force towards the wellbore and cuts in a certain azimuth towards the wellbore. And this lateral force is proportional to the offset of the drill bit. The offset can also be understood as the offset distance of the predetermined axis relative to the vertical axis of the vertical well. For the drilling tool of a vertical well, the offset of the drill bit is 0. When the angle remains unchanged, the longer the hypotenuse, the longer the corresponding right-angled side. The short right-angled side corresponding to the sine value of the hypotenuse is the aforementioned offset. That is, for the same bend angle of the bent sub, the longer the extension length of the torque transmission shaft of the bent sub, the larger the offset. Since the diameter of the wellbore is limited, the larger the offset of the drill bit, the greater the lateral cutting force generated by the drill bit on the wellbore wall, which is equivalent to the drill bit pressing on the wellhead and rotating for cutting, and thus the slope can be built. Therefore, changing the extension amount of the torque transmission shaft of the bent sub relative to the outer sleeve 1 can change the radial offset of the drill bit, and then change the build rate and the lateral force, and ensure the effect of directional drilling.

[0026] In some embodiments, the through hole is inclined relative to the outer sleeve 1, and the outer sleeve 1 is coaxially arranged with the drill pipe, so that all the drilling force of the drill pipe is transmitted to the outer sleeve 1, reducing the loss of force and ensuring that the connection between the outer sleeve 1 and the drill pipe is simpler and more reliable. It should be noted that the through hole can also be set to be parallel to the outer sleeve 1, and then the whole outer sleeve 1 is inclined relative to the drill pipe. However, this kind of connection is an angled connection and is relatively complex.

[0027] In some embodiments, the limiting member is a limiting screw 3. The limiting screw 3 is arranged at one end of the outer sleeve 1 close to the drill pipe, and multiple groups are arranged in sequence along the length direction of the outer sleeve 1. Among them, the limiting screw 3 extends radially along the through hole, and multiple limiting screws 3 in each group are distributed circumferentially along the through hole. The limiting screws 3 in the same group are in the same plane. The limiting screw 3 can be cut off by the stamping of the torque transmission shaft 2, so that the cut-off part is separated from the outer sleeve 1. The drill pipe is connected to the driving device. By adjusting the driving force of the driving device relative to the drill pipe, the driving force of the drill pipe on the outer sleeve 1 is further changed. The first end 21 of the torque transmission shaft 2 abuts against the well wall through the drill bit. By increasing the driving force, the first end 21 of the torque transmission shaft can cut off the limiting screw 3, thereby ensuring that when it is necessary to reduce the inclination building strength of the downhole drill string combination during drilling, by increasing the drilling pressure, the limiting screw 3 is cut off step by step, so that the distance between the drill bit and the drill pipe is reduced, thereby reducing the offset distance of the drill bit.

[0028] In some embodiments, the first end 21 of the torque transmission shaft has a tapered hole. The large end of the tapered hole is close to the limiting screw, and the tip is far from the limiting screw. The tapered hole is used to accommodate the cut-off limiting screw 3 without affecting the torque transmission shaft to continue cutting off other limiting screws 3 subsequently.

[0029] In some embodiments, the sliding limiting mechanism includes a spline groove 6 and a spline 5. The outer sleeve 1 includes a spline sleeve portion 11. The spline groove 6 is arranged in the spline sleeve portion 11. The spline sleeve 4 is arranged along the length direction of the through hole. The first end 21 of the torque transmission shaft is provided with a spline 5, and the spline 5 is arranged along the length direction of the torque transmission shaft 2. The spline 5 is slidably connected in the spline groove 6.

[0030] In some embodiments, the outer sleeve 1 further includes a smooth portion 12. The end of the smooth portion 12 is fixedly connected to the end of the spline sleeve portion 11 far from the drill pipe. The smooth portion 12 is provided with a smooth round hole for the torque transmission shaft to pass through. The inner diameter of the smooth round hole is smaller than the diameter of the circumferential surface surrounded by the splines, which can prevent the torque transmission shaft 2 from slipping off the outer sleeve 1 and ensure the reliability of the structure.

[0031] In some embodiments, the distance between the limiting screw 3 close to the smooth round hole and the smooth portion 12 is greater than the length of the spline 5, so as to ensure that the spline 5 is located in the spline groove between the smooth portion 12 and the limiting screw 3. With such a setting, it can be ensured that the spline 5 is always completely inside the spline sleeve 4.

[0032] In some embodiments, a sealing ring is arranged on the end face of the smooth portion 12 of the outer sleeve 1. The sealing ring is used to seal the liquid between the torque transmission shaft and the outer sleeve 1. This liquid can be drilling fluid and can play a lubricating role.

[0033] In some embodiments, the spline sleeve portion 11 is provided with a male thread for threaded connection with the drill pipe. Specifically, the drill pipe is a straight screw drill tool, and the male thread is threadedly connected to the female thread of the transmission shaft at the lower end of the straight screw drill tool, which has good reliability and is convenient for disassembly.

[0034] In some embodiments, one end of the torque transmission shaft 2 connected to the drill bit is provided with a female thread for the drill bit to be inserted.

[0035] In the present invention, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. An adjustable bending joint, characterized in that: It includes an outer sleeve, a torque transmission shaft and a limiting member. The outer sleeve is used to connect with a drill pipe, and there is a through hole inclined relative to the drill pipe inside the outer sleeve. The first end of the torque transmission shaft is arranged in the through hole, the second end extends out of the outer sleeve and is used to connect a drill bit, and the first end of the torque transmission shaft is slidably connected with the outer sleeve through a sliding limiting mechanism, so that the torque transmission shaft is axially slidably connected to the outer sleeve and the rotation of the torque transmission shaft in the circumferential direction is restricted. The limiting member is arranged in the through hole and used to abut against the first end of the torque transmission shaft. By adjusting the limiting position of the limiting member, the distance that the second end of the torque transmission shaft extends out of the outer sleeve can be adjusted. Among them, the limiting member is a limiting screw, the limiting screw is arranged at one end of the outer sleeve close to the drill pipe, and multiple rows are arranged in sequence along the length direction of the outer sleeve; among them, the limiting screw extends along the radial direction of the through hole, and multiple limiting screws in each row are distributed along the circumferential direction of the through hole. The limiting screws in the same row are in the same plane, and the limiting screw can be separated from the outer sleeve through the stamping of the torque transmission shaft.

2. The adjustable bending joint according to claim 1, characterized in that: The through hole is inclined relative to the outer sleeve, and the outer sleeve is coaxially arranged with the drill pipe.

3. The adjustable bending joint according to claim 1, characterized in that: The first end of the torque transmission shaft has a tapered hole, and the tapered hole is used to accommodate the cut-off limiting screw.

4. The adjustable bending joint according to claim 1, wherein: The sliding limiting mechanism includes a spline groove and a spline. The outer sleeve includes a spline sleeve part, and the spline groove is arranged in the spline sleeve part. The spline sleeve is arranged along the length direction of the through hole. The first end of the torque transmission shaft is provided with the spline, and the spline is arranged along the length direction of the torque transmission shaft. The spline is slidably arranged in the spline groove.

5. The adjustable bending joint according to claim 4, wherein: The outer sleeve further includes a smooth part, the smooth part is connected to one end of the spline sleeve part away from the drill pipe, and the smooth part is provided with a smooth round hole for the torque transmission shaft to pass through. The inner diameter of the smooth round hole is smaller than the diameter of the circumferential surface surrounded by the splines, which can prevent the torque transmission shaft from slipping out of the outer sleeve.

6. The adjustable bending joint according to claim 5, wherein: The distance between the limiting screw close to the smooth round hole and the smooth part is greater than the length of the spline, so as to ensure that the spline is located in the spline groove between the smooth part and the limiting screw.

7. The adjustable bending joint according to claim 5, characterized in that: A sealing ring is arranged on the end face of the smooth part of the outer sleeve, and the sealing ring is used to seal the liquid between the torque transmission shaft and the outer sleeve.

8. The adjustable bending joint according to claim 4, wherein: The spline sleeve part is provided with a male thread for threaded connection with the drill pipe connected to the driving device.

9. The adjustable bending joint according to claim 1, wherein: One end of the torque transmission shaft connected to the drill bit is provided with a female thread for the drill bit to be connected.

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