Torque reducing tool for drill stem

Abstract

The invention provides a drill stem torque reducing tool, and relates to the technical field of drilling operation of petroleum and natural gas resources. A connecting sleeve component is arranged outside a central pipe in a sleeving manner, a turbulent flow cavity is formed between the connecting sleeve component and the central pipe, and liquid resistance in the turbulent flow cavity is increased through spiral turbulent flow wings, so that liquid in the turbulent flow cavity does rotational flow motion; the rotational flow fluid can effectively take away the solid phase in the turbulent flow cavity, a better self-cleaning effect is achieved, and the technical problems that in the prior art, solid phase accumulation can occur in gaps of internal rotating parts of a traditional friction and torque reducing tool, the rotating resistance is greatly increased, and the torque reducing function is affected are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling operations for oil and gas resources, and particularly to a drill string torque reduction tool. Background Art

[0002] During the drilling process of oil and gas fields, there are more and more deep wells, complex structure wells, and high-temperature and high-pressure wells. For well control safety and to balance formation pressure, weighted mud is required. The heavy mud has a high viscosity, a large solid content, and is prone to precipitation. Under such mud conditions, the rotation torque of the drill string is high, which has a great impact on drilling efficiency.

[0003] The drill string torque reduction tool is used to change the sliding contact between the drill string and the wellbore into rolling contact, so as to achieve the effect of reducing drilling torque. Currently, the commonly used friction and torque reduction tools are all structures with rotatable bearings sleeved on the central pipe, and there is no effective self-cleaning structure. Under the conditions of high solid content of mud and high clay content in the formation, solid-phase accumulation will occur in the gaps of the rotating parts inside the bearing. As the accumulation intensifies, the rotation resistance of the torque reduction joint bearing increases significantly, and finally the rolling torque reduction function will be lost. Summary of the Invention

[0004] The purpose of the present invention is to provide a drill string torque reduction tool to alleviate the technical problems existing in the prior art, where solid-phase accumulation occurs in the gaps of the internal rotating parts of the traditional friction and torque reduction tools, resulting in a significant increase in rotation resistance and affecting the torque reduction function.

[0005] The drill string torque reduction tool provided by the present invention includes: a central pipe and a connecting sleeve member;

[0006] A plurality of spiral flow disturbing wings are arranged on the outer wall of the central pipe. The plurality of spiral flow disturbing wings are arranged at intervals along the circumferential direction of the central pipe, and the spiral flow disturbing wings are inclined relative to the radial direction of the central pipe;

[0007] The connecting sleeve member is sleeved outside the central pipe. A flow disturbing cavity is formed between the connecting sleeve member and the central pipe, and the plurality of spiral flow disturbing wings are located in the flow disturbing cavity. The spiral flow disturbing wings are used to increase the liquid resistance of the liquid entering the flow disturbing cavity, so that the liquid in the flow disturbing cavity makes a swirling motion.

[0008] Further,

[0009] The connecting sleeve member includes a rotating sleeve and a supporting connecting sleeve;

[0010] Both the rotating sleeve and the supporting connecting sleeve are sleeved on the central pipe, and the rotating sleeve and the supporting connecting sleeve are oppositely arranged and are connected to each other.

[0011] Further,

[0012] The support connection sleeve is provided with a plurality of liquid inlet holes for allowing external liquid to enter the flow disturbance chamber.

[0013] Furthermore,

[0014] The rotating sleeve is provided with a plurality of liquid outlet holes for allowing the liquid in the flow disturbance chamber to flow out.

[0015] Furthermore,

[0016] The outer diameter dimensions of the rotating sleeve and the support connection sleeve are greater than the outer diameter dimension of the central pipe, so that the annulus liquid is throttled at the rotating sleeve and the support connection sleeve, and a part of the annulus liquid flows along the annulus between the rotating sleeve and the wellbore wall, and another part of the annulus liquid enters the flow disturbance chamber through the liquid inlet holes.

[0017] Furthermore,

[0018] The drill string torque reduction tool further includes end wear rings;

[0019] There are two end wear rings, and the two end wear rings are sleeved on the central pipe, and the two end wear rings are respectively connected to the ends of the rotating sleeve and the support connection sleeve away from each other.

[0020] Furthermore,

[0021] The drill string torque reduction tool further includes limit compression nuts;

[0022] There are two limit compression nuts, and the two limit compression nuts are both sleeved on the central pipe, and the two limit compression nuts are respectively threadedly connected to the two end wear rings.

[0023] Furthermore,

[0024] The drill string torque reduction tool further includes an anti-back-off snap ring;

[0025] The anti-back-off snap ring is embedded on the outer wall of the central pipe, and the anti-back-off snap ring has elasticity and is used to abut against the limit compression nut to limit the axial movement of the limit compression nut.

[0026] Furthermore,

[0027] The drill string torque reduction tool further includes a friction reduction sleeve;

[0028] The friction reduction sleeve is sleeved on the rotating sleeve, and the rotating sleeve is provided with snap-in protrusions that are embedded in the friction reduction sleeve.

[0029] Furthermore,

[0030] The rotating sleeve is provided with a key, and the support connecting sleeve is provided with a key groove. The key extends into the key groove to connect the rotating sleeve and the support connecting sleeve.

[0031] The drill string torque reduction tool provided by the present invention forms a turbulent flow cavity between the connecting sleeve member sleeved outside the central pipe and the central pipe. By using the spiral turbulent flow wings to increase the liquid resistance in the turbulent flow cavity, the liquid in the turbulent flow cavity makes a swirling motion. The swirling fluid can effectively carry away the solid phase in the turbulent flow cavity, playing a better self-cleaning role, and alleviating the technical problem that in the prior art, in the traditional friction and torque reduction tool, solid phase accumulation will occur in the gap of the internal rotating parts, resulting in a large increase in the rotational resistance and affecting the torque reduction function. Description of the Drawings

[0032] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are 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.

[0033] Figure 1 It is a cross-sectional view of the overall structure of the drill string torque reduction tool provided by the embodiment of the present invention;

[0034] Figure 2 is Figure 1 An enlarged schematic view of the left half;

[0035] Figure 3 is Figure 1 An enlarged schematic view of the right half;

[0036] Figure 4 It is a schematic view of the structure of the central pipe and the turbulent flow wings of the drill string torque reduction tool provided by the embodiment of the present invention.

[0037] Reference numerals: 1 - central pipe; 2 - anti-retreat snap ring; 3 - limit compression cap; 4 - end wear ring; 5 - rotating sleeve; 6 - friction reduction sleeve; 7 - support connecting sleeve; 8 - spiral turbulent flow wing. Detailed Embodiments

[0038] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0039] Such as Figure 1 、 Figure 2 、 Figure 3 andFigure 4 As shown in Figure 4 , the drill string torque reduction tool provided in this embodiment includes a central pipe 1 and a connecting sleeve member. A plurality of spiral flow spoilers 8 are arranged on the outer wall of the central pipe 1. The plurality of spiral flow spoilers 8 are arranged at intervals along the circumferential direction of the central pipe 1, and the spiral flow spoilers 8 are inclined with respect to the radial direction of the central pipe 1. The connecting sleeve member is sleeved outside the central pipe 1. A flow spoiler cavity is formed between the connecting sleeve member and the central pipe 1, and the plurality of spiral flow spoilers 8 are located in the flow spoiler cavity. The spiral flow spoilers 8 are used to increase the liquid resistance of the liquid entering the flow spoiler cavity, so that the liquid in the flow spoiler cavity makes a swirling motion.

[0040] Specifically, five groups of spiral flow spoilers 8 are arranged in the middle section of the central pipe 1, with 4 vanes in each group and a vane spiral angle of 10 degrees. After the connecting sleeve member is sleeved into the central pipe 1, these spiral flow spoilers 8 are wrapped therein to form a flow spoiler cavity. The annulus liquid flows through the connecting sleeve member into the flow spoiler cavity. The spiral flow spoilers 8 increase the liquid flow resistance, so that the liquid in the flow spoiler cavity makes a swirling motion. The multiple groups of spiral flow spoilers 8 of the central pipe 1 convert the axially flowing fluid into a swirling fluid, and the swirling fluid can effectively carry away the solid phase in the flow spoiler cavity.

[0041] The drill string torque reduction tool provided in this embodiment forms a flow spoiler cavity between the connecting sleeve member sleeved outside the central pipe 1 and the central pipe 1. By using the spiral flow spoilers 8 to increase the liquid resistance in the flow spoiler cavity, the liquid in the flow spoiler cavity makes a swirling motion. The swirling fluid can effectively carry away the solid phase in the flow spoiler cavity, playing a better self-cleaning role, and alleviating the technical problem existing in the prior art that in traditional friction and torque reduction tools, solid phase accumulation will occur in the gaps of internal rotating parts, resulting in a significant increase in rotational resistance and affecting the torque reduction function.

[0042] On the basis of the above embodiment, the connecting sleeve member in the drill string torque reduction tool provided in this embodiment includes a rotating sleeve 5 and a support connecting sleeve 7. Both the rotating sleeve 5 and the support connecting sleeve 7 are sleeved on the central pipe 1, and the rotating sleeve 5 and the support connecting sleeve 7 are arranged oppositely and are connected to each other.

[0043] Specifically, the rotating sleeve 5 and the support connecting sleeve 7 are oppositely sleeved into the central pipe 1. A rectangular key is arranged at the lower end of the rotating sleeve 5 and is clamped into the corresponding keyway of the support connecting sleeve 7. There are multiple rows of circular counterbores evenly distributed at the places where the central pipe 1 contacts the support connecting sleeve 7 and the rotating sleeve 5. YG8 hard alloy is cold inlaid in the counterbores. The places where the support connecting sleeve 7 and the rotating sleeve 5 contact the central pipe 1 form a hard alloy wear-resistant layer by sintering YG8 hard alloy blocks. Finally, the contact parts of the central pipe 1 with the support connecting sleeve 7 and the rotating sleeve 5 are all covered with hard alloy, improving the wear resistance of the rotating mechanism. In addition, the friction coefficient between the hard alloys is 0.1 - 0.2, the friction coefficient is lower, and the rotational resistance is small, which can further improve the torque reduction effect.

[0044] Further, the support connection sleeve 7 is provided with a plurality of liquid inlet holes for allowing external liquid to enter the turbulent flow chamber. Specifically, there are 3 groups of liquid inlet holes evenly distributed on the end face of the support connection sleeve 7 for entering the turbulent flow chamber.

[0045] Further, the rotating sleeve 5 is provided with a plurality of liquid outlet holes for allowing the liquid in the turbulent flow chamber to flow out. Specifically, there are 6 groups of liquid outlet holes evenly distributed on the end face of the rotating sleeve 5 for flowing out of the turbulent flow chamber.

[0046] Further, the outer diameter dimensions of the rotating sleeve 5 and the support connection sleeve 7 are larger than the outer diameter dimension of the central pipe 1, so that the annulus liquid is throttled at the rotating sleeve 5 and the support connection sleeve 7. A part of the annulus liquid flows along the annulus between the rotating sleeve 5 and the wellbore, and another part of the annulus liquid enters the turbulent flow chamber through the liquid inlet holes.

[0047] Specifically, when the drilling fluid circulates, due to the large outer diameters of the support connection sleeve 7 and the rotating sleeve 5, the annulus liquid is throttled here. A part of the liquid quickly passes through the annulus between the rotating sleeve 5 and the wellbore, and a part enters the turbulent flow chamber through the liquid inlet holes of the support connection sleeve 7. For the fluid entering the turbulent flow chamber, under the flow splitting action of the spiral turbulent flow wings 8, the flow resistance increases and the flow velocity further decreases. According to the Venturi principle and Bernoulli's equation, the reduced flow velocity of the fluid is converted into an increase in fluid pressure. While the flow velocity of the fluid previously split out in the annulus between the rotating sleeve 5 and the wellbore increases and the fluid pressure decreases, forming a pressure difference with the fluid in the turbulent flow chamber. Under the action of the pressure difference, the fluid in the turbulent flow chamber is quickly drawn out from the liquid outlet holes on the end face of the rotating sleeve 5, forming a self-cleaning liquid flow cycle in the turbulent flow chamber. During the cycle, at the same time, the turbulent flow wings hinder the fluid flow and convert the flow velocity into fluid pressure. The fluid pressure acts on the turbulent flow wings, and the spiral structure of the turbulent flow wings decomposes the force, and part of the force is converted into a radial thrust. This thrust helps the pipe string to rotate forward. Through hydraulic assistance, the mechanical force required to maintain the forward rotation of the drill string can be reduced, thus realizing the function of reducing the torque of the drill string. At the same time, the support connection sleeve 7 and the rotating sleeve 5 are not restricted from rotating axially on the central pipe 1. After they contact the wellbore, the sliding friction between the drill string and the wellbore can be converted into rolling friction, thereby further reducing the rotational resistance and playing the role of reducing the torque of the drill string.

[0048] Further, the drill string torque reduction tool further includes end wear rings 4; there are two end wear rings 4, and the two end wear rings 4 are sleeved on the central pipe 1, and the two end wear rings 4 are respectively connected to the ends of the rotating sleeve 5 and the support connection sleeve 7 that are away from each other; the drill string torque reduction tool further includes limit nuts 3; there are two limit nuts 3, and the two limit nuts 3 are both sleeved on the central pipe 1, and the two limit nuts 3 are respectively threadedly connected to the two end wear rings 4; the drill string torque reduction tool further includes an anti-back-off snap ring 2; the anti-back-off snap ring 2 is embedded in the outer wall of the central pipe 1, and the anti-back-off snap ring 2 is elastic, and the anti-back-off snap ring 2 is used to abut against the limit nut 3 to limit the axial movement of the limit nut 3; the drill string torque reduction tool further includes a friction reduction sleeve 6; the friction reduction sleeve 6 is sleeved on the rotating sleeve 5, and the rotating sleeve 5 is provided with a clamping protrusion, and the clamping protrusion is embedded in the friction reduction sleeve 6.

[0049] Specifically, a set of end wear rings 4 are sleeved on the upper end of the rotating sleeve 5 and the lower end of the support connection sleeve 7 respectively. Then, two limit nuts 3 are threadedly connected at the positions of the end wear rings 4. The limit nuts 3 fix the axial displacements of the end wear rings 4, the rotating sleeve 5, and the friction reduction sleeve 6, and do not limit the rotational movement of the rotating sleeve 5 and the friction reduction sleeve 6. The anti-back-off snap ring 2 has an opening in its cross section, enabling the part to elastically expand and deform outward. After the limit nut 3 is installed in place, the anti-back-off snap ring 2 elastically expands outward and is embedded into the anti-back-off snap ring 2 installation groove on the central pipe 1 to prevent the limit nut 3 from unthreading, and the installation of the entire tool is completed.

[0050] In addition, the friction reduction sleeve 6 is made of a copolymer of PTFE (polytetrafluoroethylene) + 32% PEEK (polyetheretherketone). The rotating sleeve 5 has 14 regular trapezoidal protrusions with a height of 2 mm, a bottom side of 3 mm, and a top side of 1 mm at the position where the friction reduction sleeve 6 is fixed. The rotating sleeve 5 and the friction reduction sleeve 6 are processed by integral extrusion. These trapezoidal protrusions are embedded into the inner wall of the friction reduction sleeve 6 to achieve a firm connection between the rotating sleeve 5 and the friction reduction sleeve 6. The friction reduction sleeve 6 has a low hardness and contacts the inner wall of the casing, which can effectively protect the casing and reduce wear. At the same time, the friction coefficient of the copolymer of PTFE + 32% PEEK is 0.12, which can further enhance the torque reduction effect of the tool.

[0051] The drill string torque reduction tool provided in this embodiment has the following advantages:

[0052] 1. The tool is directly connected to the drill string. By means of the composite material bearing system, the sliding friction between the drill string and the wellbore is changed into the rolling friction of the composite material bearing, which can reduce the friction resistance and torque of the drill string during drilling.

[0053] 2. It has a turbulence chamber composed of spiral spoiler wings. Using the Venturi principle, during the circulation of the drilling fluid, a swirl and negative pressure will be formed in the inner cavity of the tool rotating assembly, effectively discharging the solid phase, ensuring that the bearing can rotate smoothly. At the same time, the spiral spoiler wing structure can divide the flow force to assist the rotation of the drill string, further reducing the rotational torque.

[0054] 3. The material of the part where the tool contacts the inner wall of the casing is a composite material. The composite material has a lower friction coefficient, which can further reduce the rotation resistance. At the same time, the composite material has low hardness and good toughness, which can effectively reduce the wear between the drill string and the inner wall of the casing during rotation and protect the casing.

[0055] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A drill string torque reduction tool, characterized in that, it includes: a central tube (1) and a connecting sleeve member; a plurality of spiral turbulators (8) are arranged on the outer wall of the central tube (1), the plurality of spiral turbulators (8) are arranged at intervals along the circumferential direction of the central tube (1), and the spiral turbulators (8) are inclined with respect to the radial direction of the central tube (1); the connecting sleeve member is sleeved outside the central tube (1), a turbulence chamber is formed between the connecting sleeve member and the central tube (1), and the plurality of spiral turbulators (8) are located in the turbulence chamber, and the spiral turbulators (8) are used to increase the liquid resistance entering the turbulence chamber, so that the liquid in the turbulence chamber makes a swirling motion.

2. The drill string torque reduction tool according to claim 1, characterized in that, the connecting sleeve member includes a rotating sleeve (5) and a supporting connecting sleeve (7); both the rotating sleeve (5) and the supporting connecting sleeve (7) are sleeved on the central tube (1), and the rotating sleeve (5) and the supporting connecting sleeve (7) are arranged oppositely and are connected to each other.

3. The drill string torque reduction tool according to claim 2, characterized in that, the supporting connecting sleeve (7) is provided with a plurality of liquid inlet holes for allowing external liquid to enter the turbulence chamber.

4. The drill string torque reduction tool according to claim 3, characterized in that, the rotating sleeve (5) is provided with a plurality of liquid outlet holes for allowing the liquid in the turbulence chamber to flow out.

5. The drill string torque reduction tool according to claim 4, characterized in that, the outer diameter dimensions of the rotating sleeve (5) and the supporting connecting sleeve (7) are larger than the outer diameter dimension of the central tube (1), so that the annulus liquid is throttled at the rotating sleeve (5) and the supporting connecting sleeve (7), and a part of the annulus liquid flows along the annulus between the rotating sleeve (5) and the wellbore wall, and another part of the annulus liquid enters the turbulence chamber through the liquid inlet holes.

6. The drill string torque reduction tool according to claim 2, characterized in that, the drill string torque reduction tool further includes end wear rings (4); there are two end wear rings (4), the two end wear rings (4) are sleeved on the central tube (1), and the two end wear rings (4) are respectively connected to the ends of the rotating sleeve (5) and the supporting connecting sleeve (7) away from each other.

7. The drill string torque reduction tool according to claim 6, characterized in that, the drill string torque reduction tool further includes a limit compression cap (3); there are two limit compression caps (3), both the two limit compression caps (3) are sleeved on the central tube (1), and the two limit compression caps (3) are respectively threadedly connected to the two end wear rings (4).

8. The drill string torque reduction tool according to claim 7, characterized in that, the drill string torque reduction tool further includes an anti-back-off snap ring (2); The anti-retreat snap ring (2) is embedded on the outer wall of the central tube (1), and the anti-retreat snap ring (2) is elastic. The anti-retreat snap ring (2) is used to abut against the limit cap (3) to limit the axial movement of the limit cap (3).

9. The drill string torque reduction tool according to claim 2, characterized in that, the drill string torque reduction tool further comprises an antifriction sleeve (6); the antifriction sleeve (6) is sleeved on the rotating sleeve (5), and the rotating sleeve (5) is provided with a clamping protrusion which is embedded in the antifriction sleeve (6).

10. The drill string torque reduction tool according to claim 2, characterized in that, the rotating sleeve (5) is provided with a key, and the support connection sleeve (7) is provided with a keyway. The key extends into the keyway to connect the rotating sleeve (5) and the support connection sleeve (7).

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