Screw drag reducer

Abstract

A screw drag reducer comprises a screw power assembly, a valve disc assembly and a lower joint, wherein the lower end of the screw power assembly is threadedly connected to the upper end of the lower joint, the screw power assembly comprises a power sleeve and a screw stator fixed in the power sleeve, a screw rotor is arranged in the screw stator, the lower end of the screw rotor is connected to the valve disc assembly through a connecting shaft, the valve disc assembly comprises a static valve disc fixedly connected in the lower joint and a dynamic valve disc fixedly connected to the connecting shaft, the dynamic valve disc is provided with a first eccentric hole, and the static valve disc is provided with a second eccentric hole, a transition hole and a liquid outlet; therefore, the present invention has a simple structure and convenient operation and maintenance, effectively overcomes the defects of the prior art, further improves the drilling effect and drilling efficiency, improves the vibration efficiency, and effectively avoids pressure holding.

Description

Technical Field

[0001] The invention relates to the technical field of drilling for oil and natural gas exploration operations, and in particular to a screw drag reducer with improved efficiency and stable impact. Background Art

[0002] With the continuous development of human scientific and technological life, the demand and supply for resources are also increasing. The oil and natural gas on the earth's surface have been gradually exhausted. Therefore, the depth of oil and gas exploration drilling is increasing, resulting in more complex drilling structures.

[0003] When drilling with current conventional technology, the drilling cycle is longer and there are more complex situations encountered during the drilling process. The drill bit is prone to friction with the well wall during drilling. These frictions are axial friction generated during sliding drilling and circumferential friction generated during rotary drilling. These frictions can easily cause damage to the drill bit.

[0004] In order to avoid the defects caused by these frictions, many countries are vigorously developing drilling tools, among which pulse drag reduction drilling tools that reduce friction through hydraulic pulses have been rapidly developed and researched. In the existing drilling tools of this type, a vibration component and a power component are usually combined, and hydraulic power is used to provide rotational power for the power component. The power and vibration components are then used to provide axial oscillation of the drill tool to reduce the friction between the drill tool and the well wall. This structure can improve the sliding drilling effect and the efficiency of directional drilling to a certain extent.

[0005] However, the existing pulse drag reduction drilling tools are prone to pressure build-up and have low efficiency.

[0006] To this end, in view of the above-mentioned defects, the designers of the present invention have devoted themselves to research and design, and combined the experience and achievements of long-term work in related industries to research and design a screw drag reducer to overcome the above-mentioned defects. Summary of the invention

[0007] The purpose of the present invention is to provide a screw drag reducer, which has a simple structure, is easy to operate and maintain, effectively overcomes the defects of the prior art, further improves the drilling effect and drilling efficiency, and effectively avoids pressure build-up.

[0008] To achieve the above object, the present invention discloses a screw drag reducer, comprising a screw power assembly, a valve disc assembly and a lower joint, wherein the lower end of the screw power assembly is threadedly connected to the upper end of the lower joint, the screw power assembly comprises a power sleeve and a screw stator fixed in the power sleeve, a screw rotor is arranged in the screw stator, and the characteristics are:

[0009] The lower end of the screw rotor is connected to the valve disc assembly through a connecting shaft. The valve disc assembly includes a static valve disc fixedly connected to the lower joint and a dynamic valve disc fixedly connected to the connecting shaft. The lower joint forms a step-shaped accommodating cavity that gradually increases from top to bottom at the periphery of the dynamic valve disc. The dynamic valve disc is arranged in the accommodating cavity. The dynamic valve disc includes a disc-shaped dynamic valve body. A liquid inlet chamber is provided in the dynamic valve body. A plurality of liquid inlet holes arranged at equal angles are provided on the peripheral wall of the liquid inlet chamber. A first eccentric hole is provided below the liquid inlet chamber. The static valve disc includes a disc-shaped static valve body. The center axes of the dynamic valve disc and the static valve disc coincide with each other. The static valve body is provided with a second eccentric hole. The static valve body is provided with a transition hole above the second eccentric hole. The upper end of the transition hole is connected to the first eccentric hole, and the lower end is connected to the second eccentric hole. The static valve body is provided with a liquid outlet below the second eccentric hole.

[0010] Wherein: the upper end of the movable valve body is fixed to the connecting shaft, and a part of its periphery is rotatably fixed to the inner wall of the lower joint through a bearing element.

[0011] Wherein: the liquid inlet hole is inclined at a certain angle, and the liquid inlet hole is set at 45 degrees.

[0012] Wherein: the transition hole is a non-eccentric hole and its diameter is greater than or equal to the maximum eccentric diameter of the first eccentric hole, and the maximum eccentric diameter of the second eccentric hole is less than or equal to the maximum eccentric diameter of the first eccentric hole.

[0013] Wherein: the axial thickness of the transition hole is 1 / 5 to 1 / 6 of the axial thickness of the first eccentric hole, and the axial thickness of the second eccentric hole is greater than or equal to the axial thickness of the first eccentric hole.

[0014] Wherein: a detachable vibration changing member is arranged in the transition hole, and the vibration changing member is a disc structure and is provided with a plurality of through-going changing holes.

[0015] Among them: another detachable vibration changing member is arranged at the liquid outlet, and the vibration changing member is also a disc structure and is also provided with a plurality of changing holes.

[0016] Wherein: the vibration changing member and another vibration changing member are detachably connected and fixed by means of threaded connection.

[0017] From the above content, it can be known that the screw drag reducer of the present invention has the following effects:

[0018] 1. Simple structure, convenient operation and maintenance, effectively overcome the defects of the existing technology, and further improve the drilling effect and drilling efficiency.

[0019] 2. The specially designed valve disc assembly not only improves vibration efficiency but also effectively avoids pressure build-up.

[0020] The details of the present invention can be obtained from the following description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The schematic diagram of the structure of the screw drag reducer of the present invention is shown.

[0022] Figure 2 A schematic structural diagram of a valve disc assembly in one embodiment of the present invention is shown.

[0023] Figure 3 A schematic structural diagram of a valve disc assembly in another embodiment of the present invention is shown. Description of the drawings:

[0025] 14. Screw power assembly; 15. Lower joint; 16. Connecting shaft; 17. Moving valve disc; 18. Static valve disc; 111. Connecting shaft; 141. Power sleeve; 142. Screw stator; 143. Screw rotor. DETAILED DESCRIPTION

[0026] See also Figure 1 , Figure 2 and Figure 3 , showing the screw drag reducer of the present invention.

[0027] The screw drag reducer comprises a screw power assembly 14, a valve disc assembly and a lower joint 15. The lower end of the screw power assembly 14 is threadedly connected to the upper end of the lower joint 15. The screw power assembly 14 comprises a power sleeve 141 and a screw stator 142 fixed in the power sleeve 141. The upper and lower ends of the power sleeve 141 are both provided with connecting threads. A screw rotor 143 is provided in the screw stator 142. Thus, the screw rotor 143 is located in the spiral cavity of the screw stator 142. When the fluid enters the spiral cavity of the screw stator 142, the screw rotor 143 is driven to rotate, so that the pressure of the high-pressure drilling fluid is converted into the rotational motion of the screw rotor 143, and the lower end of the screw rotor 143 is connected to the valve disc assembly through the connecting shaft 16, and the valve disc assembly 16 includes a static valve disc 18 fixedly connected to the lower joint 15 and a movable valve disc 17 fixedly connected to the connecting shaft 16. Radial mechanical vibration is generated by the valve disc assembly and transmitted outward through the entire shell to effectively reduce the friction and drag between the drill pipe and the well wall.

[0028] Among them, Figure 1 and Figure 2As shown, in one embodiment of the present invention, the lower joint 15 forms a stepped accommodating cavity that gradually increases from top to bottom at the periphery of the movable valve disc 17, and the movable valve disc 17 is arranged in the accommodating cavity. The movable valve disc 17 includes a disc-shaped movable valve body 171. The upper end of the movable valve body 171 can be fixed to the connecting shaft 16 by welding or the like, and a part of its periphery can be rotatably fixed to the inner wall of the lower joint 15 by a bearing element, as shown in FIG. Figure 2 As shown, the movable valve body 171 is provided with a liquid inlet chamber 172, and a plurality of liquid inlet holes 173 arranged at equal angles and intervals are provided on the peripheral wall of the liquid inlet chamber 172. A first eccentric hole 174 is provided below the liquid inlet chamber 172. Figure 2 As shown, the liquid inlet hole 173 is inclined at a certain angle to facilitate better liquid inlet. Preferably, the liquid inlet hole 173 is preferably set at 45 degrees.

[0029] Among them, the static valve disc 18 includes a disc-shaped static valve body 181, and the central axes of the movable valve disc 17 and the static valve disc 18 are arranged to coincide with each other. A second eccentric hole 183 is arranged in the static valve body 181. The corresponding arrangement of the first eccentric hole 174 and the second eccentric hole 183 enables the two eccentric holes to produce a periodically changing flow area when the movable valve disc 17 follows the rotation of the connecting shaft 16 and the screw rotor 143, and then the pressure of the high-pressure drilling fluid generates pressure pulses during the periodic flow, effectively reducing axial and circumferential friction.

[0030] Among them, although the direct corresponding connection between the first eccentric hole 174 and the second eccentric hole 183 can realize direct periodic changes in pressure, this structural setting also has the problem of easy transition changes and excessively sharp pressure peaks. For this reason, the static valve body 181 of the present invention is provided with a transition hole 182 above the second eccentric hole 183, and the upper end of the transition hole 182 is connected to the first eccentric hole 174, and the lower end is connected to the second eccentric hole 183. The transition hole 182 is a non-eccentric hole and its diameter is greater than or equal to the maximum eccentric diameter of the first eccentric hole 174, and the maximum eccentric diameter of the second eccentric hole 183 is less than or equal to the maximum eccentric diameter of the first eccentric hole 174. The corresponding relationship of this size can be shown as follows: Figure 2As shown, through the setting of the transition hole 182, the pressure of the high-pressure drilling fluid will not directly act on the transition area between the first eccentric hole 174 and the second eccentric hole 183, thereby avoiding the problem of too sharp pressure peak. In order to avoid energy loss, the thickness of the transition hole 182 is smaller than the thickness of the first eccentric hole 174 and the second eccentric hole 183. Preferably, the axial thickness of the transition hole 182 is 1 / 5 to 1 / 6 of the axial thickness of the first eccentric hole 174, and the axial thickness of the second eccentric hole 183 is greater than or equal to the axial thickness of the first eccentric hole 174. Therefore, through the specific setting of this structure, the pressure pulses of the two eccentric holes can be realized, and the problem of too sharp pulses can be effectively avoided, so as to achieve smoother and more stable pulses, effectively improve the vibration efficiency, and better avoid pressure holding.

[0031] Preferably, the static valve body 181 is provided with a liquid outlet 184 below the second eccentric hole 183, the upper end of the liquid outlet 184 is connected to the second eccentric hole 183, and the lower end is connected to the outside of the static valve body 181. The provision of the liquid outlet 184 can better provide the outflow of liquid and avoid the liquid from being directly discharged outward from the second eccentric hole 183. Due to the relative deflection position of the second eccentric hole, the pressure of the liquid suddenly decreases when the liquid is sprayed out, forming transitional wear in a certain direction on the inner side of the static valve body 181, which can easily lead to overall damage and replacement of the static valve body 181. The provision of the liquid outlet 184 can more effectively avoid this problem. The diameter of the liquid outlet 184 is larger than the diameter of the transition hole 182. This structure can form a transition area for liquid output inside the static valve body 18. The pressurized liquid will not directly rush out of the inner wall facing the static valve body, but will be further discharged through the liquid outlet 184. The larger diameter of the liquid outlet can better avoid the pressure reduction effect of liquid spraying, thereby achieving effective protection of the inner wall of the static valve body.

[0032] Among them, Figure 3 As shown, in another embodiment of the present invention, the technical solution of the present invention can further set a detachable vibration changing member 185 in the transition hole 182, and the vibration changing member 185 is a disc structure and is provided with a plurality of through-going change holes, and the change holes can make certain changes to the pressure pulses between the moving valve disc and the static valve disc, thereby providing different vibration frequencies and vibration amplitudes, and such changes can be set as needed, such as a plurality of change holes are arranged at equal angles on the vibration changing member 185, so that when the pressure liquid is subjected to a pressure pulse from the first eccentric hole to the second eccentric hole, its vibration amplitude can be increased by a sudden change in the cross-sectional area, and the diameter and flow area of ​​the change hole determine the change in the vibration amplitude, therefore, through the setting of the vibration changing member, a wider range of vibration changes can be provided for different needs, so that different needs can be met by providing different vibration changing members without providing different static valve discs.

[0033] In this embodiment, another detachable vibration changing member 186 can be provided at the liquid outlet 184. The vibration changing member 186 is also a disc structure and can also be provided with a plurality of change holes. Due to the position of the other vibration changing member 186, the amplitude and influence of the change are relatively small. However, due to the influence of the axial thickness of the transition hole 182, the thickness and size of the vibration changing member 185 provided therein are also limited. When a larger range of adjustment is required, the thickness and hole position of the other vibration changing member can be adjusted to better provide a change range.

[0034] The vibration changing member 185 and the other vibration changing member 186 can be detachably connected and fixed by means of threaded connection.

[0035] Therefore, through the arrangement of the above structure, the present invention has the following advantages:

[0036] 1. Simple structure, convenient operation and maintenance. The output of pressure pulses is achieved through the setting of the screw rotor and valve disc assembly, which produces axial reciprocating vibration and effectively reduces axial and circumferential friction.

[0037] 2. The eccentric hole arrangement of the valve disc assembly, as well as the setting of the transition hole and liquid outlet, can provide a wider and more stable pulse output, meet a wider range of needs, and can further improve the service life of the valve disc assembly and the overall device, and reduce the cost of use.

[0038] It is obvious that the above description and record are only examples and are not intended to limit the disclosure, application or use of the present invention. Although the embodiments have been described in the embodiments and described in the drawings, the present invention is not limited to the specific examples of the teachings of the present invention as the best mode currently considered by the drawings and described in the embodiments, and the scope of the present invention will include any embodiment falling within the previous description and the attached claims.

Claims

1. A screw drag reducer, comprising a screw power assembly, a valve disc assembly and a lower joint, wherein the lower end of the screw power assembly is threadedly connected to the upper end of the lower joint, the screw power assembly comprises a power sleeve and a screw stator fixed in the power sleeve, a screw rotor is arranged in the screw stator, and the characteristics are: The lower end of the screw rotor is connected to the valve disc assembly through a connecting shaft. The valve disc assembly includes a static valve disc fixedly connected to the lower joint and a movable valve disc fixedly connected to the connecting shaft. The lower joint forms a step-shaped accommodating cavity that gradually increases from top to bottom at the periphery of the movable valve disc. The movable valve disc is arranged in the accommodating cavity. The movable valve disc includes a disc-shaped movable valve body. A liquid inlet chamber is arranged in the movable valve body. A plurality of liquid inlet holes arranged at equal angles are arranged on the peripheral wall of the liquid inlet chamber. A first eccentric hole is arranged below the liquid inlet chamber. The static valve disc includes a disc The static valve body is shaped like a moving valve disc, and the center axes of the moving valve disc and the static valve disc are arranged to coincide with each other. The static valve body is provided with a second eccentric hole, and the static valve body is provided with a transition hole above the second eccentric hole. The upper end of the transition hole is connected to the first eccentric hole, and the lower end is connected to the second eccentric hole to avoid the problem of too sharp pressure peak. The transition hole is a non-eccentric hole and its diameter is greater than or equal to the maximum eccentric diameter of the first eccentric hole, and the maximum eccentric diameter of the second eccentric hole is less than or equal to the maximum eccentric diameter of the first eccentric hole. The static valve body is provided with a liquid outlet below the second eccentric hole; A detachable vibration changing part is arranged in the transition hole, and the vibration changing part is a disc structure and has a plurality of through-going change holes. Another detachable vibration changing part is arranged at the liquid outlet, and the vibration changing part is also a disc structure and has a plurality of change holes, thereby being able to provide different vibration frequencies and vibration amplitudes.

2. The screw drag reducer according to claim 1, characterized in that: The upper end of the movable valve body is fixed to the connecting shaft, and a part of the periphery thereof is rotatably fixed to the inner wall of the lower joint through a bearing element.

3. The screw drag reducer according to claim 1, characterized in that: The liquid inlet hole is inclined at a certain angle, and the liquid inlet hole is set at 45 degrees.

4. The screw drag reducer according to claim 1, characterized in that: The axial thickness of the transition hole is 1 / 5 to 1 / 6 of the axial thickness of the first eccentric hole, and the axial thickness of the second eccentric hole is greater than or equal to the axial thickness of the first eccentric hole.

5. The screw drag reducer according to claim 1, characterized in that: The vibration changing member and another vibration changing member are detachably connected and fixed by means of threaded connection.

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