Drill rod torque reducer

Abstract

The present invention provides a drill rod torque reducer, comprising: an inner sleeve sleeved on the drill rod; two slips axially pressed and installed between the inner sleeve and the drill rod radially from both ends of the inner sleeve; an outer sleeve sleeved on the outside of the inner sleeve, the outer sleeve and the inner sleeve having a clearance fit; and a pressing mechanism symmetrically arranged at both axial ends of the inner sleeve; wherein the drill rod torque reducer is arranged between the drill rod and the casing outside the drill rod, the pressing mechanism is configured to press the slips axially inwardly, so that the inner sleeve can rotate synchronously with the drill rod, and the outer sleeve can rotate relative to the inner sleeve through the pressing mechanism, so that the outer sleeve and the casing outside the drill rod are relatively stationary.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum drilling tools, and in particular relates to a drill rod torque reducer. Background Art

[0002] In the drilling of large-displacement wells, high-angle wells, horizontal wells and deep wells, or in well sections with greater dogleg severity, or in the long open hole drilling process after the technical casing is lowered, the casing used often has wear problems. The damage of the technical casing often brings great difficulties to the construction of the lower part of the well, such as casing breakage, dislocation, and deformation, resulting in resistance to drilling. In addition, the resulting reduction in the casing's anti-collision strength and internal pressure strength restricts the smooth progress of the subsequent completion test operations of the oil well, reduces the life of the oil well, and in severe cases may lead to the scrapping of a section of the oil well and the scrapping of the entire oil well.

[0003] In the traditional drilling construction process, the drill pipe rubber hoop is mainly used. For example, in the prior art, there are drill pipe, casing wear protectors or deep well and ultra-deep well casing wear protectors. These wear protectors are formed by fixing the rubber sleeve on the drill pipe through a metal skeleton through a locking block. They protect the casing by wearing the rubber sleeve, but they have the problems that the rubber sleeve is easy to tear, has a short service life, and is easy to fall off, causing downhole complications. In the prior art, there are also anti-wear joints, which are connected at both ends of the drill pipe. Many anti-wear joints with threaded connections are added to the drill string. However, too many threaded connections increase the unsafe factors of drilling, resulting in reduced safety performance of drilling. Summary of the invention

[0004] In response to the technical problems mentioned above, the present invention aims to propose a drill pipe torque reducer, which is arranged between the drill pipe and the casing. It can make the casing outside the drill pipe rotate relative to the drill pipe while remaining stationary, so as to avoid contact dynamic friction between the inner wall of the casing and the drill string, effectively prevent wear of the casing and the drill string, and can withstand a certain axial tension to avoid disintegration of the casing and damage, resulting in downhole complications.

[0005] To this end, according to the present invention, a drill rod torque reducer is provided, comprising: an inner sleeve sleeved on the drill rod; two slips axially pressed from both ends of the inner sleeve and installed between the inner sleeve and the drill rod in a radial direction; an outer sleeve sleeved on the outside of the inner sleeve, the outer sleeve and the inner sleeve having a clearance fit; and a pressing mechanism symmetrically arranged at both axial ends of the inner sleeve; wherein the drill rod torque reducer is arranged between the drill rod and the casing outside the drill rod, and the pressing mechanism is configured to press the slips axially inwardly, so that the inner sleeve can rotate synchronously with the drill rod, and the outer sleeve can rotate relative to the inner sleeve through the pressing mechanism, so that the outer sleeve and the casing outside the drill rod are relatively stationary.

[0006] In one embodiment, the clamping mechanism includes a thrust bearing and a clamping nut arranged at the end of the inner sleeve. The clamping nut is arranged axially outside the thrust bearing and is threadedly connected to the outer sleeve. The cava can be axially clamped by tightening the clamping nut.

[0007] In one embodiment, a pressure plate is provided between the inner sleeve and the thrust bearing for transmitting axial pressing force.

[0008] In one embodiment, it is characterized in that the inner sleeve includes two separately arranged first bodies and second bodies, and the first bodies and the second bodies are assembled through a dovetail groove structure to form the inner sleeve.

[0009] In one embodiment, the inner diameter of the inner sleeve is configured to decrease axially inward from both ends, so that the inner walls at both ends of the inner sleeve form a first conical surface.

[0010] In one embodiment, the outer wall surface of the slip is configured as a second conical surface, so that the slip can be adapted to be installed between the first conical surface and the drill pipe.

[0011] In one embodiment, the taper of the second tapered surface is the same as the taper of the first tapered surface.

[0012] In one embodiment, the cava is constructed to include two separately arranged and structurally identical cava bodies, which clamp the drill pipe under the axial clamping force of the clamping mechanism and make the first conical surface and the second conical surface press together, thereby making the inner sleeve stationary relative to the drill pipe.

[0013] In one embodiment, the inner wall surface of the slip body is provided with saw-shaped teeth.

[0014] In one embodiment, the outer sleeve is made of low carbon steel.

[0015] Compared with the prior art, the advantages of the present invention are:

[0016] The drill pipe torque reducer according to the present invention is installed between the drill pipe and the outer casing of the drill pipe, and its inner sleeve can withstand a certain circumferential torque through the slips, and can be stationary relative to the drill pipe, and remain stationary relative to the casing outside the drill pipe. At the same time, the inner sleeve can rotate relative to the outer sleeve through the clamping mechanism, thereby making the outer sleeve stationary relative to the outer casing of the drill pipe, thereby avoiding contact dynamic friction between the inner wall of the casing and the drill string, effectively preventing the casing and the drill string from being worn, and being very beneficial to extending the service life of the casing. Moreover, the slips can withstand a certain axial tension under the action of the clamping mechanism, thereby effectively avoiding the disintegration of the casing and damage that leads to underground complexity, and enhancing the safety performance of on-site construction. In addition, the drill pipe torque reducer has a simple structure and is easy to install, which is beneficial to improving on-site construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be described below with reference to the accompanying drawings.

[0018] Figure 1 The structure of the drill rod torque reducer according to the present invention is shown.

[0019] Figure 2 Shows Figure 1 The structure of the inner sleeve in the drill pipe torque reducer is shown.

[0020] Figure 3 Shows Figure 1 The structure of the slips in the drill pipe torque reducer is shown.

[0021] In the present application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

[0022] The present invention will be described below with reference to the accompanying drawings.

[0023] Figure 1 The structure of the drill pipe torque reducer 100 according to the present invention is shown. The drill pipe torque reducer 100 is used to be installed between the drill pipe and the casing in the well to reduce the friction between the drill pipe and the casing, thereby avoiding the wear of the casing and the drill string. Figure 1 As shown, the drill pipe torque reducer 100 includes an inner sleeve 2 sleeved on the drill pipe 1, two slips 3 axially pressed and installed between the inner sleeve 2 and the drill pipe 1 in the radial direction from the two ends of the inner sleeve 2, an outer sleeve 4 sleeved on the outside of the inner sleeve 2, and a pressing mechanism 5 symmetrically arranged at the two ends of the inner sleeve 2. The pressing mechanism 5 can press the corresponding slips 3 axially inward, so that the two slips 3 are axially relatively close, so that the inner sleeve 2 forms a pressing fit with the drill pipe 1 and is stationary relative to the drill pipe 1, and can rotate relative to the outer sleeve 4, so that the outer sleeve 4 can be stationary relative to the casing outside the drill pipe. In this way, the contact dynamic friction between the inner wall of the casing and the drill string is prevented, thereby avoiding the wear of the casing and the drill string.

[0024] Both ends of the drill pipe 1 extend to the axial ends of the inner sleeve 2 and extend axially outward, and are used to connect other downhole drill pipes or other components through drill pipe joints (not shown).

[0025] like Figure 1 and Figure 2 As shown, the inner sleeve 2 includes two split first bodies 21 and second bodies 22. In one embodiment, the semi-cylindrical first body 21 and second body 22 are assembled through a dovetail groove structure to form a cylindrical inner sleeve 2. The split inner sleeve 2 is easy to install on site to the outside of the drill rod 1. When the drill rod 1 is long or connected to other components, the inner sleeve 2 can be installed without disassembly, which is very convenient for improving the installation efficiency of the drill rod torque reducer 100 and is conducive to improving the efficiency of on-site operations.

[0026] According to the present invention, the inner diameters of the two ends of the inner sleeve 2 are set to decrease from the two axial ends to the middle, so that the inner walls of the two ends of the inner sleeve 2 form a first conical surface, and the middle area of ​​the inner wall of the inner sleeve 2 forms a cylindrical surface. The outer surface of the inner sleeve 2 is a cylindrical surface. Preferably, the structures of the two axial ends of the inner sleeve 2 are set to be symmetrical relative to the axial middle. The function of the first conical surface is introduced below.

[0027] In one embodiment, the inner diameter of the middle region of the inner sleeve 2 is slightly larger than the outer diameter of the drill rod 1. This makes it easier to install the inner sleeve 2 on the outside of the drill rod 1.

[0028] like Figure 1 As shown, the outer sleeve 4 is concentrically sleeved on the outer side of the inner sleeve 2. The outer sleeve 4 is an integral cylindrical structure. The axial length of the outer sleeve 4 is greater than the axial length of the inner sleeve 2. The clamping mechanism 5 is arranged at the axial ends of the inner sleeve 2, and the clamping mechanism 5 includes a thrust bearing 51 and a clamping nut 52 arranged at the end of the inner sleeve 2, and the clamping nut 52 is arranged on the axial outer side of the thrust bearing 51. The clamping mechanism 5 is arranged between the axial outer side portion of the outer sleeve 4 extending to the inner sleeve 2 and the radial direction of the drill pipe 1. In one embodiment, internal threads are provided on the inner walls at both ends of the outer sleeve 4, and the clamping nut 52 is connected to the outer sleeve 4 by threads, so that the thrust bearing 51 can be axially pushed by tightening the clamping nut 52 to axially compress the slip 3.

[0029] In order to prevent the sleeve from being worn, the outer sleeve 4 can be made of low-carbon steel material, for example.

[0030] In this embodiment, the thrust bearing 51 can be, for example, a leg ball bearing or a diamond thrust bearing. The inner diameter of the thrust bearing 51 is slightly larger than the outer diameter of the drill rod joint of the drill rod 1 used on site for easy installation and connection.

[0031] According to the present invention, a pressure plate 53 is provided between the inner sleeve 2 and the thrust bearing 51. The pressure plate 53 is a split circular plate, and an inner hole is provided in the middle, and the inner hole diameter is larger than the outer diameter of the drill pipe. The pressure plate 53 is located at the axial outer end of the slip 3, and is used to transmit the axial pressing force applied by the clamping nut 52 to the slip 3, so as to axially push the slip 3 to be axially pressed and installed between the inner sleeve 2 and the radial direction of the drill pipe 1.

[0032] like Figure 3 As shown, the outer diameter of the slip 3 is set to be Figure 3 The upper end in the middle) to the axial inner end ( Figure 3 The outer wall surface of the slip 3 is formed into a second conical surface, so that the slip 3 can be adapted to be installed between the first conical surface of the inner sleeve 2 and the radial direction of the drill pipe 1. The taper of the second conical surface is set to be the same as the taper of the first conical surface of the inner sleeve 2.

[0033] According to the present invention, the slip 3 is constructed to include two split-type slip bodies 31 with the same structure, and the slip body 31 is semi-cylindrical. The two slips 3 are symmetrically installed between the first conical surface at both ends of the inner sleeve 2 and the drill pipe 1. When the clamping mechanism 5 axially presses the slip 3, the slip body 31 holds the drill pipe 1 tightly under the action of the axial clamping force. Moreover, under the action of the friction force between the first conical surface and the second conical surface, the slip 3 and the inner sleeve 2 are pressed together to make the inner sleeve 2 bear a certain circumferential torque, so that the inner sleeve 2 can rotate synchronously with the drill pipe, that is, the inner sleeve 2 is stationary relative to the drill pipe 1 through the slip 3. At the same time, the inner sleeve 2 can rotate relative to the outer sleeve 4 through the thrust bearing 51, so that the outer sleeve 4 does not rotate with the outer sleeve of the drill pipe, even if the outer sleeve 4 is stationary relative to the outer sleeve of the drill pipe. As a result, the contact dynamic friction between the inner wall of the casing and the drill string can be effectively prevented, the wear of the casing and the drill string can be avoided, and the service life of the casing can be effectively extended.

[0034] In one embodiment, a saw-shaped tooth 32 is provided on the inner wall surface of the slip body 31. Furthermore, a plurality of grooves extending along the axial direction may be provided on the inner surface and / or the outer surface of the slip 3, and the plurality of grooves are evenly distributed along the circumferential direction. This can increase the axial force that the slip 3 bears after holding the drill pipe 1 tightly, and effectively ensure that the slip 3 rotates stably with the drill pipe 1.

[0035] According to the present invention, the two clamping mechanisms 5 correspondingly arranged at the upper and lower ends of the inner sleeve 2 are identical, so that a symmetrical clamping structure is formed at the two ends of the inner sleeve 2. In actual operation, the same axial clamping force can be applied to the slips 3 at both ends of the inner sleeve 2 by screwing the corresponding clamping nuts 52, and transmitted to the slips 3 through the thrust bearings 52 and the pressure plates 53, so that the slips 3 hold the drill rod 1 tightly through the inner wall sawtooth teeth 32, and at the same time, the second conical surface of the slips 3 is pressed and matched with the first conical surface of the inner sleeve 2, thereby, the inner sleeve 2 and the drill rod 1 are relatively stationary, and the inner sleeve 2 can rotate synchronously with the drill rod 1. At the same time, the inner sleeve 2 can rotate relative to the outer sleeve 4 under the action of the thrust bearings 52 of the clamping mechanism 5, so that the outer sleeve 4 does not rotate with the inner sleeve 2 but is stationary relative to the outer sleeve of the drill rod, thereby avoiding relative friction between the outer sleeve 4 and the outer sleeve of the drill rod and causing wear.

[0036] The drill pipe torque reducer 100 according to the present invention is installed between the drill pipe 1 and the drill pipe outer casing, and its inner sleeve 2 can withstand a certain circumferential torque through the slip 3, and can be stationary relative to the drill pipe 1, and remain stationary relative to the casing outside the drill pipe. At the same time, the inner sleeve 2 can rotate relative to the outer sleeve 4 through the clamping mechanism 5, thereby making the outer sleeve 4 stationary relative to the drill pipe outer casing, thereby avoiding the contact dynamic friction between the inner wall of the casing and the drill string, effectively preventing the casing and the drill string from being worn, and being very beneficial to extending the service life of the casing. In addition, the slip 3 can withstand a certain axial tension under the action of the clamping mechanism 5, thereby effectively avoiding the disintegration of the casing and damage that causes underground complexity, and enhancing the safety performance of on-site construction. In addition, the drill pipe torque reducer 100 has a simple structure and is easy to install, which is beneficial to improving on-site construction efficiency.

[0037] Finally, it should be noted that the above is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A drill pipe torque reducer, comprising: An inner sleeve (2) sleeved on the drill rod (1); Two slips (3) are axially pressed and installed between the inner sleeve and the drill pipe in a radial direction from both ends of the inner sleeve; An outer sleeve (4) sleeved on the outside of the inner sleeve, the outer sleeve and the inner sleeve being in clearance fit; A clamping mechanism (5) symmetrically arranged at two axial ends of the inner sleeve; Wherein, the drill rod torque reducer is arranged between the drill rod and the casing outside the drill rod, and the clamping mechanism is configured to be able to axially compress the slips inward so that the inner sleeve can rotate synchronously with the drill rod, and the outer sleeve can rotate relative to the inner sleeve through the clamping mechanism, so that the outer sleeve and the casing outside the drill rod are relatively stationary.

2. The drill pipe torque reducer according to claim 1, characterized in that: The clamping mechanism comprises a thrust bearing (51) and a clamping nut (52) arranged at the end of the inner sleeve. The clamping nut is arranged axially outside the thrust bearing and is threadedly connected to the outer sleeve. The slip can be axially clamped by tightening the clamping nut.

3. The drill pipe torque reducer according to claim 2, characterized in that: A pressure plate (53) is provided between the inner sleeve and the thrust bearing for transmitting axial pressing force.

4. The drill rod torque reducer according to any one of claims 1 to 3, characterized in that: The inner sleeve comprises a first body (21) and a second body (22) which are arranged separately, and the first body and the second body are assembled through a dovetail groove structure to form the inner sleeve.

5. The drill rod torque reducer according to any one of claims 1 to 3, characterized in that: The inner diameter of the inner sleeve is arranged to decrease axially inward from both ends, so that the inner walls at both ends of the inner sleeve form a first conical surface.

6. The drill pipe torque reducer according to claim 5, characterized in that: The outer wall surface of the slip is configured as a second conical surface so that the slip can be adapted and installed between the first conical surface and the drill pipe.

7. The drill pipe torque reducer according to claim 6, characterized in that: The taper of the second tapered surface is the same as the taper of the first tapered surface.

8. The drill pipe torque reducer according to claim 7, characterized in that: The slip structure comprises two slip bodies (31) which are arranged separately and have the same structure. The two slip bodies hold the drill pipe tightly under the axial pressing force of the pressing mechanism, and make the first conical surface and the second conical surface press together, so that the inner sleeve is stationary relative to the drill pipe.

9. The drill pipe torque reducer according to claim 7, characterized in that: The inner wall surface of the slip body is provided with saw-shaped teeth (32).

10. The drill pipe torque reducer according to claim 1 or 2, characterized in that: The outer sleeve is made of low carbon steel material.

Images