An impact-resistant support section for downhole motor drill

Abstract

The present invention discloses an impact-resistant support section of a downhole motor drill, which includes a housing, a main shaft, a fixed bearing, a movable bearing, a damper and a disc spring. The housing has a long strip-shaped accommodating cavity; the main shaft is disposed inside the accommodating cavity; the fixed bearing has a first moving ring and a first fixed ring; the movable bearing has a second moving ring and a second fixed ring; the damper has a third fixed ring and a third moving ring. The third moving ring is connected to the first moving ring and is slidably disposed in the annular groove. A second flow hole communicating with the annular groove is formed in the third moving ring, and the second flow hole communicates with the accommodating cavity; the disc spring is sleeved on the main shaft, one end of the disc spring abuts against the second fixed ring, and the other end of the disc spring abuts against the third fixed ring. The beneficial effect of the present invention is that the disc spring and the damper are used in cooperation for shock absorption, and the shock absorption effect is good. At the same time, the drilling fluid is used to cool each component, thereby further extending the service life of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling tools, and in particular to an impact-resistant support section of a downhole motor drill Background Art

[0002] The support section is an important part of the downhole motor drill, mainly playing the roles of straightening the drill string, transmitting power to the bit, bearing axial drilling pressure, pulsating load and radial disturbance. It is also called the bearing section or the transmission assembly in some literatures. It connects the bit and the power section of the drill string, and its structure mainly includes a main shaft, an intermediate housing, a thrust bearing, a centralizing bearing, a spline shaft, upper and lower joints, etc. The support section and the power section are used in cooperation to better exert the output characteristics of the downhole motor drill.

[0003] In the structure of the support section of the downhole motor drill (such as the Chinese utility model patent with the application number CN201420632562.3), the bearing adopted by the support section is a very weak part, and the life of the bearing seriously restricts the overall service life of the power drill. The working life of the thrust bearing of an ordinary turbodrill is within 150h, and the recommended replacement period of the thrust bearing of a positive displacement motor is only 60 - 80h, and the life is shorter during deep well operations. It is necessary to frequently raise the drill pipe to replace the bearing, wasting a lot of time and reducing work efficiency. When working in hard geological formations, the bit vibrates greatly at the bottom of the well, resulting in unstable working conditions of the thrust bearing, aggravating the wear of the bearing. At the same time, the thrust bearing will have a relatively high temperature due to friction, further reducing the working life. Summary of the Invention

[0004] In view of this, it is necessary to provide an impact-resistant support section of a downhole motor drill to solve the technical problem that the existing support section of the downhole motor drill has a short service life due to strong vibration and friction heating.

[0005] To achieve the above object, the present invention provides an impact-resistant support section of a downhole motor drill, including a housing, a main shaft, a fixed bearing, a movable bearing, a damper and a disc spring;

[0006] The housing has a long strip-shaped accommodating cavity for passing drilling fluid;

[0007] The main shaft is disposed in the accommodating cavity and is parallel to the extending direction of the housing;

[0008] The fixed bearing has a first moving ring and a first stationary ring, the first moving ring is slidably sleeved on the main shaft, and the first stationary ring is fixed to the housing;

[0009] The movable bearing has a second moving ring and a second stationary ring, the second moving ring is fixedly sleeved on the main shaft, and the second stationary ring is slidably connected to the housing;

[0010] The damper has a third stationary ring and a third moving ring. The third stationary ring is slidably disposed in the housing and is provided with an annular groove that cooperates with the third moving ring. The third stationary ring is further provided with a first flow-through hole that communicates with the annular groove. The third moving ring is connected to the first moving ring and is slidably disposed in the annular groove. The third moving ring is provided with a second flow-through hole that communicates with the annular groove, and the second flow-through hole communicates with the accommodation cavity.

[0011] The disc spring is sleeved on the main shaft. One end of the disc spring abuts against the second stationary ring, and the other end of the disc spring abuts against the third stationary ring.

[0012] In some embodiments, the shock-resistant downhole motor drill string support section further includes a spline shaft. One end of the spline shaft is fixedly connected to the main shaft. The spline shaft and the main shaft are both hollow shafts and communicate with each other. The spline shaft is provided with a flow-in hole that communicates with the accommodation cavity.

[0013] In some embodiments, the shock-resistant downhole motor drill string support section further includes a fixed collar. One end of the fixed collar is fixedly connected to the first stationary ring, and the other end of the fixed collar is fixedly connected to the housing.

[0014] In some embodiments, sealing rings are respectively disposed at both ends of the housing. The inner ring of the sealing ring is sealingly connected to the main shaft, and the outer ring of the sealing ring is sealingly connected to the inner wall of the housing.

[0015] In some embodiments, the sealing ring is a rotary lip seal.

[0016] In some embodiments, the first moving ring is slidably sleeved on the main shaft via a first flat key.

[0017] In some embodiments, the second moving ring is fixedly sleeved on the main shaft via a second flat key.

[0018] In some embodiments, an upper sub is connected to one end of the housing, and a lower sub is connected to the other end of the housing.

[0019] In some embodiments, a limiting groove is provided on the first stationary ring, and a limiting portion is formed on the third stationary ring. The limiting portion is slidably disposed in the limiting groove.

[0020] In some embodiments, there are two of the movable bearings, the dampers and the disc springs, and they are symmetrically arranged on both sides of the fixed bearing respectively.

[0021] Compared with the prior art, the beneficial effects of the technical solution proposed by the present invention are as follows: When the drill bit hits the rock, an upward impact load will be generated. The main shaft will move upward under the action of the impact load, and at the same time drive the second moving ring upward. The second moving ring drives the second fixed ring to move upward, and the second fixed ring compresses the disc spring. When the disc spring contracts, it drives the third fixed ring to move upward. When the third fixed ring moves upward, since the third moving ring is limited by the first moving ring and cannot move up and down, therefore, the third fixed ring will move upward relative to the third moving ring, so that the drilling fluid in the annular groove will be extruded, thereby reducing the impact and changing the rigid impact into a flexible impact. When the upward impact load is absorbed, the main shaft will move downward due to its own gravity and the action of the drilling fluid pressure and gravity. At this time, the annular groove will be filled with drilling fluid, so as to realize the cyclic absorption of the impact load and the drilling pressure. Since the present invention uses a disc spring and a damper to cooperate for shock absorption, the shock absorption effect is good, and at the same time, the drilling fluid is used to cool each component, thereby further extending the service life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the front view of an embodiment of the shock-resistant downhole motor drill string support section provided by the present invention;

[0023] Figure 2 is Figure 1 the sectional view of section A-A in

[0024] Figure 3 is Figure 2 the enlarged partial view of area B in

[0025] Figure 4 is Figure 2 the schematic perspective structure diagram of the downhole motor drill string support section in

[0026] In the figure: 1 - housing, 11 - sealing ring, 2 - main shaft, 3 - fixed bearing, 31 - first moving ring, 311 - first flat key, 32 - first fixed ring, 4 - movable bearing, 41 - second moving ring, 411 - second flat key, 42 - second fixed ring, 5 - damper, 51 - third fixed ring, 511 - first flow hole, 512 - limiting part, 52 - third moving ring, 521 - second flow hole, 53 - annular groove, 6 - disc spring, 7 - spline shaft, 71 - inlet hole, 8 - fixed collar, 91 - upper joint, 92 - lower joint. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will specifically describe the preferred embodiments of the present invention in conjunction with the drawings. Among them, the drawings form a part of this application and are used together with the embodiments of the present invention to explain the principle of the present invention, and are not used to limit the scope of the present invention.

[0028] Please refer to Figures 1-3, the present invention provides an impact-resistant downhole motor support section, comprising a housing 1, a main shaft 2, a fixed bearing 3, a movable bearing 4, a damper 5 and a disc spring 6.

[0029] The housing 1 has a long-shaped receiving cavity for passing drilling fluid. The main shaft 2 is disposed within the receiving cavity and is parallel to the extending direction of the housing 1.

[0030] The fixed bearing 3 has a first moving ring 31 and a first stationary ring 32. The first moving ring 31 is slidably sleeved on the main shaft 2 and can slide relative to the length direction of the main shaft 2 but cannot rotate relative to the main shaft 2. The first stationary ring 32 is fixed to the housing 1. Thus, when the main shaft 2 rotates, the first moving ring 31 rotates while the first stationary ring 32 does not rotate due to being fixed to the housing 1.

[0031] The movable bearing 4 has a second moving ring 41 and a second stationary ring 42. The second moving ring 41 is fixedly sleeved on the main shaft 2, and the second stationary ring 42 is slidably connected to the housing 1. The second stationary ring 42 can slide axially relative to the housing 1 but cannot rotate relative to the housing 1. Thus, when the main shaft 2 rotates, the second moving ring 41 rotates while the second stationary ring 42 does not rotate.

[0032] The damper 5 has a third stationary ring 51 and a third moving ring 52. The third stationary ring 51 is slidably disposed within the housing 1 and is provided with an annular groove 53 that mates with the third moving ring 52. The third stationary ring 51 can slide axially relative to the housing 1 but cannot rotate relative to the housing 1. The third stationary ring 51 is further provided with a first flow hole 511 communicating with the annular groove 53. The third moving ring 52 is connected to the first moving ring 31 and is slidably disposed within the annular groove 53. In this embodiment, the third moving ring 52 is fixedly connected to the first moving ring 31. The third moving ring 52 is provided with a second flow hole 521 communicating with the annular groove 53, and the second flow hole 521 communicates with the receiving cavity.

[0033] The disc spring 6 is sleeved on the main shaft 2. One end of the disc spring 6 abuts against the second stationary ring 42, and the other end of the disc spring 6 abuts against the third stationary ring 51.

[0034] During use, after the main shaft 2 is connected to the power device, the main shaft 2 rotates, and the first moving ring 31 and the second moving ring 41 rotate together with the main shaft 2. The third moving ring 52 rotates together with the first moving ring 31, while the first fixed ring 32, the second fixed ring 42, and the third fixed ring 51 do not rotate. Drilling fluid flows into the accommodating cavity. When the drill bit hits the rock, an upward impact load will be generated. The main shaft 2 will move upward under the action of the impact load, and at the same time drive the second moving ring 41 to move upward. The second moving ring 41 drives the second fixed ring 42 to move upward, and the second fixed ring 42 compresses the disc spring 6. When the disc spring 6 contracts, it drives the third fixed ring 51 to move upward. When the third fixed ring 51 moves upward, since the third moving ring 52 is limited by the first moving ring 31 and cannot move up and down, therefore, the third fixed ring 51 will move upward relative to the third moving ring 52, so that the drilling fluid in the annular groove 53 will be extruded, thereby reducing the impact and turning the rigid impact into a flexible impact. When the upward impact load is absorbed, the main shaft 2 will move downward due to its own gravity and the action of the drilling fluid pressure and gravity. At this time, the annular groove 53 will be filled with drilling fluid, thus realizing the cyclic absorption of the impact load and the drilling pressure. Since the present invention uses the disc spring 6 and the damper 5 to cooperate for shock absorption, the shock absorption effect is good, and at the same time, the drilling fluid is used to cool each component, thereby further extending the service life of the device.

[0035] For the convenience of connecting the power device, please refer to Figure 2 and Figure 4 , in a preferred embodiment, the shock-resistant downhole power drill support section further includes a spline shaft 7. One end of the spline shaft 7 is fixedly connected to the main shaft 2. The spline shaft 7 and the main shaft 2 are both hollow shafts and communicate with each other. An inflow hole 71 communicating with the accommodating cavity is provided on the spline shaft 7, so as to facilitate the entry of drilling fluid.

[0036] For the specific realization of the fixed connection between the first fixed ring 32 and the housing 1, please refer to Figure 2 and Figure 4 , in a preferred embodiment, the shock-resistant downhole power drill support section further includes a fixed collar 8. One end of the fixed collar 8 is fixedly connected to the first fixed ring 32, and the other end of the fixed collar 8 is fixedly connected to the housing 1.

[0037] To improve the sealing effect, please refer to Figure 2 , in a preferred embodiment, sealing rings 11 are respectively built in at both ends of the housing 1. The inner ring of the sealing ring 11 is sealingly connected to the main shaft 2, and the outer ring of the sealing ring 11 is sealingly connected to the inner wall of the housing 1, so as to prevent the drilling fluid from leaking out between the housing 1 and the main shaft 2.

[0038] To improve the use effect, please refer to Figure 2 , in a preferred embodiment, the sealing ring 11 is a rotary lip seal.

[0039] To specifically implement the connection between the first moving ring 31 and the main shaft 2, please refer to Figure 2 In a preferred embodiment, the first moving ring 31 is slidably sleeved on the main shaft 2 via a first flat key 311.

[0040] To specifically implement the connection between the second moving ring 41 and the main shaft 2, please refer to Figure 2 In a preferred embodiment, the second moving ring 41 is fixedly sleeved on the main shaft 2 via a second flat key 411.

[0041] To facilitate the connection to the drill tool, please refer to Figure 1 and Figure 2 In a preferred embodiment, an upper sub 91 is connected to one end of the housing 1, and a lower sub 92 is connected to the other end of the housing 1.

[0042] To prevent the third fixed ring 51 from rotating relative to the housing 1, please refer to Figure 4 In a preferred embodiment, a limiting groove is formed on the first fixed ring 32, a limiting portion 512 is formed on the third fixed ring 51, and the limiting portion 512 is slidably disposed in the limiting groove. Thus, under the limitation of the limiting groove, the third fixed ring 51 cannot rotate relative to the housing 1.

[0043] To improve the usage effect, please refer to Figure 2 and Figure 4 In a preferred embodiment, there are two of the movable bearings 4, the dampers 5, and the disc springs 6, and they are symmetrically arranged on both sides of the fixed bearing 3 respectively.

[0044] To better understand the present invention, the following is combined with Figures 1-4The working process of the impact-resistant downhole power drilling tool support section provided by the present invention is described in detail: when in use, after the main shaft 2 is connected to the power device, the main shaft 2 rotates, the first movable ring 31 and the second movable ring 41 rotate together with the main shaft 2, the third movable ring 52 rotates together with the first movable ring 31, the first fixed ring 32, the second fixed ring 42 and the third fixed ring 51 do not rotate, and the drilling fluid flows into the accommodating chamber; when the drill bit hits the rock, an upward impact load will be generated, and the main shaft 2 will move upward under the impact load, while driving the second movable ring 41 to move upward, and the second movable ring 41 drives the second fixed ring 42 upward The second fixed ring 42 compresses the disc spring 6, and the disc spring 6 drives the third fixed ring 51 to move upward when it contracts. When the third fixed ring 51 moves upward, the third movable ring 52 cannot move up and down due to the limitation of the first movable ring 31. Therefore, the third fixed ring 51 will move upward relative to the third movable ring 52, so that the drilling fluid in the annular groove 53 will be squeezed out, thereby slowing down the impact and turning the rigid impact into a flexible impact. When the upward impact load is absorbed, the main shaft 2 will move downward due to its own gravity and the drilling fluid pressure and gravity. At this time, the annular groove 53 will be filled with drilling fluid, thereby realizing the reciprocating absorption of impact loads and drilling pressure. Since the present invention adopts disc spring 6 and damper 5 to cooperate with shock absorption, the shock absorption effect is good, and at the same time, the various components are cooled by the drilling fluid, thereby further extending the service life of the device.

[0045] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An impact-resistant downhole motor drill string support section, characterized in that, it includes a housing, a main shaft, a fixed bearing, a movable bearing, a damper and a disc spring; the housing has a long accommodating cavity for drilling fluid to flow through; the main shaft is placed inside the accommodating cavity and is parallel to the extending direction of the housing; the fixed bearing has a first moving ring and a first stationary ring, the first moving ring is slidably sleeved on the main shaft, and the first stationary ring is fixed to the housing; the movable bearing has a second moving ring and a second stationary ring, the second moving ring is fixedly sleeved on the main shaft, and the second stationary ring is slidably connected to the housing; the damper has a third stationary ring and a third moving ring, the third stationary ring is slidably arranged inside the housing and is provided with an annular groove matching with the third moving ring, the third stationary ring is also provided with a first flow hole communicating with the annular groove, the third moving ring is connected to the first moving ring and is slidably arranged in the annular groove, the third moving ring is provided with a second flow hole communicating with the annular groove, and the second flow hole communicates with the accommodating cavity; the disc spring is sleeved on the main shaft, one end of the disc spring abuts against the second stationary ring, and the other end of the disc spring abuts against the third stationary ring; when the drill bit hits a rock, an upward impact load will be generated. The main shaft will move upward under the action of the impact load, and at the same time drive the second moving ring to move upward. The second moving ring drives the second stationary ring to move upward, and the second stationary ring compresses the disc spring. When the disc spring contracts, it drives the third stationary ring to move upward. When the third stationary ring moves upward, since the third moving ring is limited by the first moving ring and cannot move up and down, therefore, the third stationary ring will move upward relative to the third moving ring, so that the drilling fluid in the annular groove will be extruded, thereby reducing the impact and turning the rigid impact into a flexible impact. When the upward impact load is absorbed, the main shaft will move downward due to its own gravity and the pressure and gravity of the drilling fluid. At this time, the annular groove will be filled with drilling fluid, so as to realize the cyclic absorption of the impact load and the drilling pressure.

2. The impact-resistant downhole motor drill string support section according to claim 1, characterized in that, it further includes a spline shaft, one end of the spline shaft is fixedly connected to the main shaft, the spline shaft and the main shaft are both hollow shafts and communicate with each other, and the spline shaft is provided with a flow hole communicating with the accommodating cavity.

3. The impact-resistant downhole motor drill string support section according to claim 1, characterized in that, it further includes a fixed collar, one end of the fixed collar is fixedly connected to the first stationary ring, and the other end of the fixed collar is fixedly connected to the housing.

4. The impact-resistant downhole motor drill string support section according to claim 1, characterized in that, sealing rings are respectively arranged at both ends of the housing, the inner ring of the sealing ring is sealingly connected to the main shaft, and the outer ring of the sealing ring is sealingly connected to the inner wall of the housing.

5. The impact-resistant downhole motor drill string support section according to claim 4, characterized in that, the sealing ring is a rotary lip seal.

6. The impact-resistant downhole motor drill string support section according to claim 1, characterized in that, The first moving ring is sleeved on the main shaft in a sliding manner via a first flat key.

7. The shock-resistant downhole motor drill string support section according to claim 1, wherein, The second moving ring is fixedly sleeved on the main shaft via a second flat key.

8. The shock-resistant downhole motor drill string support section according to claim 1, wherein, One end of the housing is connected with an upper sub, and the other end of the housing is connected with a lower sub.

9. The shock-resistant downhole motor drill string support section according to claim 1, wherein, A limiting groove is formed in the first fixed ring, a limiting portion is formed on the third fixed ring, and the limiting portion is slidably arranged in the limiting groove.

10. The shock-resistant downhole motor drill string support section according to claim 1, wherein, There are two of the movable bearings, the dampers and the disc springs, and they are symmetrically arranged on both sides of the fixed bearing respectively.

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