All-metal positive displacement downhole motor

Abstract

The present invention belongs to the technical field of oil drilling, and particularly relates to a full-metal positive-displacement downhole motor. The adopted technical solution includes a connecting sleeve, a connecting rod valve, a limiting ball, a limiting cover, a chuck, a piston, a right-handed worm, a housing, a flat thrust ball bearing, a left-handed worm, a series bearing, a one-way shaft, an upper end cover, an upper one-way bearing, a lower one-way bearing, a connecting shaft, a spring, a lower sub, an axial limiting bearing, and a lower end cover. The connecting rod valve, the chuck and the piston cooperate to control the drilling fluid to push the double worms to move axially and circumferentially along the spiral internal teeth on the inner surface of the housing, and the generated rotation is transmitted to the drill bit through the one-way bearing. When moving to the lower limit position, the chuck and the piston control the drilling fluid to release pressure, and the reaction force of the spring causes the whole to reset. The present invention provides a full-metal positive-displacement downhole motor, which is applied to the exploration of high-temperature and high-pressure deep wells, has strong drilling force, high reliability, and strong applicability.

Description

Technical Field

[0001] The invention belongs to the technical field of oil drilling, and particularly relates to a full-metal positive-displacement downhole motor. Background Art

[0002] With the continuous exploitation of resources such as oil and natural gas, most of the shallow oil and gas resources are approaching exhaustion. Moreover, relevant research shows that deep oil and gas resources account for 93% of the total resources. Therefore, the drilling of oil and gas resources is gradually tending towards deep wells and ultra-deep wells. However, with the continuous increase in the drilling depth and downhole temperature, the requirements for drilling equipment by high temperature are becoming more and more stringent, and the power provided on the ground cannot meet the rock-breaking requirements. The downhole motor can greatly improve problems such as insufficient efficiency and easy deviation. Among them, the life of the screw downhole motor is greatly reduced as the temperature rises; the turbine downhole motor is sensitive to oil-based drilling fluids and is not suitable for working in high-density drilling fluids; the electric motor cannot work in a high-temperature environment either. Conventional downhole motors have many limitations and inconveniences in the drilling of deep wells and ultra-deep wells. Therefore, a downhole motor with strong adaptability, high reliability, and low cost is necessary at this stage. Summary of the Invention

[0003] The purpose of the invention is to provide a full-metal positive-displacement downhole motor with strong adaptability and high efficiency.

[0004] To achieve the above-mentioned invention purpose, the technical solution adopted by the invention is: a full-metal positive-displacement downhole motor, which is composed of a connecting sleeve, a connecting rod valve, a limiting ball, a limiting cover, a chuck, a piston, a right-handed worm, a housing, a flat thrust ball bearing, a left-handed worm, a series bearing, a one-way shaft, an upper end cover, an upper one-way bearing, a lower one-way bearing, a connecting shaft, a spring, a lower sub, an axial limiting bearing, and a lower end cover; both ends of the full-metal positive-displacement downhole motor are detachably connected; the full-metal positive-displacement downhole motor is coaxial; one end of the connecting sleeve is connected to the housing, and the other end is a drilling fluid inlet; a limiting ball is arranged between the connecting rod valve and the limiting cover; the limiting cover and the piston are connected by a double-headed bolt; the end of the connecting rod valve is welded to the chuck; the piston is located in the inner hole of the housing and is matched with the right-handed worm through a flat thrust ball bearing, and the right-handed worm is key-connected to the one-way shaft; the inner surface of the housing is provided with a right-handed spiral internal tooth and a left-handed spiral internal tooth, and the right-handed spiral internal tooth, the left-handed spiral internal tooth and the housing are connected by a pin; the right-handed worm and the left-handed worm are connected by a flat thrust ball bearing; the left-handed worm and the one-way shaft are connected by a series bearing; the one-way shaft is welded to the lower one-way bearing, and the left-handed worm is welded to the upper one-way bearing; the lower one-way bearing is welded to the connecting shaft, and the upper one-way bearing is welded to the connecting shaft; the connecting shaft is spline-mated with the lower sub; the lower sub is axially limited to the lower end cover and the housing through an axial limiting bearing.

[0005] Preferably, there are two connecting sleeves, and bosses are provided on the inner surface of the connecting sleeves; a limiting groove is provided on the part of the connecting rod valve 2 between the limiting cover and the piston, and an upper limiting ring and a lower limiting ring are provided in the limiting groove; the limiting ball is controlled by the locking mechanism of the limiting cover, and by rotating the locking screw to squeeze or release the locking spring and the pressing block, the relative acting force between the limiting cover and the connecting rod valve is adjusted.

[0006] Preferably, a sealing ring is used to seal between the piston and the outer shell, the inner surface of the outer shell is surface-treated, and an oil injection hole is provided at the outer surface of the outer shell corresponding to the right-handed spiral internal teeth and the left-handed spiral internal teeth.

[0007] Preferably, there is a radial gap between the left-handed worm and the one-way shaft; there is a radial gap between the left-handed worm and the upper end cover.

[0008] Preferably, the upper one-way bearing and the lower one-way bearing are sequentially installed in the inner hole of the connecting shaft; there is an axial gap between the upper one-way bearing and the lower one-way bearing.

[0009] Preferably, a spring is provided between the spring hole of the connecting shaft and the lower joint; the upper end of the spring is welded to the lower surface of the connecting shaft, and the lower end of the spring is welded to the upper surface of the spring hole of the lower joint.

[0010] Preferably, the connecting shaft axially moves in the inner hole formed by the lower joint and the upper end cover, the connecting shaft axially moves downward and rotates under the thrust of the lower one-way bearing and the upper one-way bearing, and axially moves upward and rotates under the reaction force of the spring; the upper end cover and the lower joint are connected by bolts.

[0011] Preferably, there is a clearance fit between the lower joint and the outer shell, and they can rotate relative to each other.

[0012] Preferably, the all-metal positive displacement downhole motor connecting sleeve and the lower joint are respectively connected to oil drilling tools.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The present invention provides a brand-new downhole motor. This all-metal positive displacement downhole motor has strong adaptability. Compared with the current mainstream downhole motors, it uses the hydraulic pressure of drilling fluid to drive the rotation of the double worms, and can generate impact to assist rock breaking.

[0015] 2. All parts of the present invention can be made of high-temperature-resistant metals, can drill deep wells, are not easy to fail in the complex and changeable downhole environment, are easy to operate, and do not require special training for operators.

[0016] 3. The present invention is ingeniously designed, only requires hydraulic drive of drilling fluid, has low manufacturing cost and low maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention;

[0018] Figure 2 It is an overall external view schematic diagram of the present invention;

[0019] Figure 3 It is an assembly schematic diagram of two connecting sleeves in the present invention

[0020] Figure 4 It is a structural schematic diagram of the connecting rod valve;

[0021] Figure 5 It is an internal structural schematic diagram of the limit cover

[0022] Figure 6 It is a sectional schematic diagram of the lower joint;

[0023] Figure 7 It is a top view of the lower joint;

[0024] Explanation of reference numerals: 1. Connecting sleeve, 101. Upper connecting sleeve, 102 Lower connecting sleeve; 2. Connecting rod valve, 201. Connecting rod valve valve, 202. Upper limit ring, 203. Lower limit ring; 3. Limit ball; 4. Limit cover, 401. Locking screw, 402. Locking spring, 403. Pressure block; 5. Chuck; 6. Piston; 7. Right-handed worm; 8. Outer shell; 9. Flat thrust ball bearing; 10. Left-handed worm; 11. String bearing; 12. One-way shaft; 13. Upper end cover; 14. Upper one-way bearing; 15. Lower one-way bearing; 16. Connecting shaft; 17. Spring; 18. Lower joint, 1801. Spring hole, 1802. Threaded hole, 1803. Rectangular spline; 19. Axial limit bearing; 20. Lower end cover. Detailed implementation manners

[0025] The present invention will be further described below in conjunction with the accompanying drawings of the specification:

[0026] Such as Figure 1 、 Figure 2 shown full-metal positive displacement downhole motor. It should be noted that: the full-metal positive displacement downhole motor can be used in a variety of drilling situations; the present invention will be applied to oil drilling, but it is not limited to this application only.

[0027] Such as Figure 1As shown in the figure: The all-metal positive displacement downhole motor consists of a connecting sleeve 1, a connecting rod valve 2, a limiting ball 3, a limiting cover 4, a chuck 5, a piston 6, a right-handed worm 7, a housing 8, a flat thrust ball bearing 9, a left-handed worm 10, a string bearing 11, a one-way shaft 12, an upper end cover 13, an upper one-way bearing 14, a lower one-way bearing 15, a connecting shaft 16, a spring 17, a lower sub 18, an axial limiting bearing 19, and a lower end cover 20; both ends of the all-metal positive displacement downhole motor are detachably connected; the all-metal positive displacement downhole motor is coaxial; one end of the connecting sleeve 1 is connected to the housing 8, and the other end is the drilling fluid inlet; a limiting ball 3 is arranged between the connecting rod valve 2 and the limiting cover 4, and the limiting cover 4 restricts the axial relative movement of the connecting rod valve 2 through the limiting ball 3 and the upper limiting ring 202 and the lower limiting ring 203; the limiting cover 4 is assembled with the piston 6 through six stud bolts, and the end of the connecting rod valve 2 is welded to the chuck 5, and the chuck 5 is located between the piston 6 and the limiting cover 4; the piston 6 is located in the inner hole of the housing 8 and is matched with the right-handed worm 7 through a flat thrust ball bearing, and the right-handed worm 7 is key-connected to the one-way shaft 12; the inner surface of the housing 8 is provided with a right-handed spiral internal tooth and a left-handed spiral internal tooth, and the right-handed spiral internal tooth and the left-handed spiral internal tooth are connected to the housing 8 through pins; the lower end surface of the right-handed worm 7 is connected to the upper end surface of the left-handed worm 10 through a flat thrust ball bearing 9; the inner surface of the left-handed worm 10 is connected to the outer surface of the one-way shaft 12 through a string bearing 11; the one-way shaft 12 is welded to the lower one-way bearing 15, and the left-handed worm 10 is welded to the upper one-way bearing 14; the lower one-way bearing 15 is welded to the connecting shaft 16, and the upper one-way bearing 14 is welded to the connecting shaft 16; the connecting shaft 16 is in spline fit with the lower sub 18, and a spring 17 is arranged between the connecting shaft 16 and the lower sub 18; the lower sub 18 is connected to the upper end cover 13 through screws; the lower sub 18 is axially limited to the housing 8 through the axial limiting bearing 19 and the lower end cover 20.

[0028] As Figure 1 , Figure 2 , Figure 4 shown: In the above solution, there are two connecting sleeves 1, which are divided into an upper connecting sleeve 101 and a lower connecting sleeve 102, and both have bosses on their inner surfaces; the connecting rod valve 201 of the connecting rod valve 2 reciprocates axially within the limiting interval formed by the bosses of the two connecting sleeves 1; a limiting groove is arranged in the part of the connecting rod valve 2 between the limiting cover and the piston, and an upper limiting ring 202 and a lower limiting ring 203 are arranged in the limiting groove.

[0029] As Figure 1 , Figure 4 , Figure 5 shown: In the above solution, the limiting ball 3 is controlled by the locking mechanism of the limiting cover 4, and by rotating the locking screw 401 to squeeze or loosen the locking spring 402 and the pressing block 403, the relative acting force between the limiting cover 4 and the connecting rod valve 2 is adjusted.

[0030] As Figure 1 shown: In the above solution, a sealing ring is used to seal between the piston 6 and the housing 8. The inner surface of the housing 8 is surface-treated, and oil injection holes are provided at the corresponding outer surfaces of the right-handed spiral internal teeth and the left-handed spiral internal teeth. The right-handed worm 7 rotates along the right-handed spiral internal teeth on the upper part of the inner surface of the housing. The left-handed worm 10 rotates along the left-handed spiral internal teeth on the lower part of the inner surface of the housing.

[0031] As Figure 1 shown: In the above solution, the left-handed worm 10 has a radial clearance fit with the one-way shaft 12 and does not interfere with each other. The left-handed worm 10 has a radial clearance fit with the upper end cover 13.

[0032] As Figure 1 shown: In the above solution, the upper one-way bearing 14 and the lower one-way bearing 15 are sequentially installed in the inner hole of the connecting shaft. There is a gap axially between the upper one-way bearing 14 and the lower one-way bearing 15.

[0033] As Figure 1 、 Figure 6 shown: In the above solution, a spring 17 is provided between the shaft end of the connecting shaft 16 and the spring hole 1801 of the lower joint. The upper end of the spring 17 is welded to the lower surface of the connecting shaft 16, and the lower end of the spring 17 is welded to the upper surface of the spring hole 1801 of the lower joint.

[0034] As Figure 1 、 Figure 6 、 Figure 7 shown: In the above solution, the connecting shaft 16 moves axially in the inner hole formed by the lower joint 18 and the upper end cover 13. The connecting shaft 16 moves axially downward and rotates under the thrust of the lower one-way bearing 15 and the upper one-way bearing 14, and moves axially upward and rotates under the reaction force of the spring 17. The upper end cover 13 and the lower joint 18 are connected by bolts.

[0035] As Figure 1 shown: In the above solution, there is a clearance fit between the lower joint 18 and the housing 8, and they can rotate relative to each other.

[0036] As Figure 1 shown: In the above solution, the all-metal positive displacement downhole motor connector 1 and the lower joint 18 are respectively connected to the oil drilling tools.

[0037] The working process of the all-metal positive displacement downhole motor is introduced below through the drawings.

[0038] Taking Figure 1The state shown is the starting state. At this time, the connecting rod valve 201 is in close contact with the boss of the connecting sleeve 101. The limiting ball 3 is in the limiting groove formed by the upper limiting ring 202. The chuck 5 is in close contact with the piston 6, and the valve hole of the piston 6 is closed. When the drilling fluid enters the tool from the connecting sleeve 1, the drilling fluid pushes the chuck 5 and the piston 6, driving the connecting rod valve 2, the one-way shaft 12 and the right-handed worm 7 to move downward. There is no relative movement between the connecting rod valve 2 and the limiting cover 4. While the right-handed worm 7 moves downward, it rotates clockwise along the right-handed spiral internal teeth 801 in the housing 8. Under the thrust of the right-handed worm 7, the left-handed worm 10 moves downward and rotates counterclockwise along the left-handed spiral internal teeth 802. The right-handed worm 7 transmits the clockwise rotation to the connecting shaft 16 through the lower one-way bearing 15. Due to the existence of the upper one-way bearing 14, the counterclockwise rotation generated by the downward movement of the left-handed worm 10 will not be transmitted to the connecting shaft 16. Therefore, while the connecting shaft 16 moves downward, it rotates clockwise. The connecting shaft 16 transmits the clockwise rotation to the lower joint 18 through the rectangular spline 1803. At this time, the spring 17 is compressed.

[0039] When the connecting rod valve 201 is forced to stop when it contacts the boss of the lower connecting sleeve 102, the limiting ball 3 and the limiting cover 4 move downward relative to the connecting rod valve 2 into the limiting groove formed by the lower limiting ring 203. During this movement, the chuck 5 moves upward relative to the piston 6. The drilling fluid passes through the valve hole of the piston 6, flows into the inner holes of the one-way shaft 12 and the connecting shaft 16, and then is discharged from the inner holes of the lower joint 18 and the drill bit, thereby relieving pressure. At this time, the reaction force of the spring 17 causes the connecting shaft 16 to move upward. The connecting shaft 16 pushes the one-way shaft 12, the piston 6 and the connecting rod valve 2 upward. There is no relative movement between the connecting rod valve and the limiting cover 4. Under the thrust of the connecting shaft 16, the left-handed worm 10 moves upward and rotates clockwise along the left-handed spiral internal teeth 802, and transmits the clockwise rotation to the connecting shaft 16 and the lower joint 18 through the upper one-way bearing 14. Under the thrust of the connecting shaft 16, the right-handed worm 7 moves upward and rotates counterclockwise along the right-handed spiral internal teeth 801. Due to the existence of the lower one-way bearing 15, the counterclockwise rotation generated by the upward movement of the right-handed worm 7 will not be transmitted to the connecting shaft 16. Therefore, while the connecting shaft 16 moves downward, it still maintains clockwise rotation, so that the lower joint maintains clockwise rotation.

[0040] When the connecting rod valve 201 is forced to stop when it contacts the boss of the upper connecting sleeve 101, the limiting ball 3 and the limiting cover 4 move upward relative to the connecting rod valve 2 into the limiting groove formed by the upper limiting ring 202. The chuck 5 moves downward relative to the piston 6. When the valve hole of the piston 6 is blocked by the chuck 5, it returns to the tool state as shown in Figure 1 The drilling fluid cannot pass through, and hydraulic pressure is generated again, and this cycle continues.

[0041] The above content is only an example and explanation of the structure of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution. As long as they do not deviate from the structure of the invention or exceed the scope defined by this claims, they shall fall within the protection scope of the present invention.

Claims

1. A fully metal positive displacement downhole motor, characterized in that: The all-metal positive displacement downhole motor consists of a connecting sleeve (1), a connecting rod valve (2), a limiting ball (3), a limiting cover (4), a chuck (5), a piston (6), a right-handed worm (7), a housing (8), a flat thrust ball bearing (9), a left-handed worm (10), a tandem bearing (11), a one-way shaft (12), an upper end cap (13), an upper one-way bearing (14), a lower one-way bearing (15), a connecting shaft (16), a spring (17), a lower sub (18), an axial limiting bearing (19), and a lower end cap (20); both ends of the all-metal positive displacement downhole motor are detachably connected; all components of the all-metal positive displacement downhole motor are coaxial; one end of the connecting sleeve (1) is connected to the housing (8), and the other end is a drilling fluid inlet; a limiting ball (3) is arranged between the connecting rod valve (2) and the limiting cover (4); the limiting cover is connected to the piston (6) by a double-headed bolt; the chuck (5) is welded to the end of the connecting rod valve (2); the piston (6) is located in the inner hole of the housing (8), and is matched with the right-handed worm (7) through a flat thrust ball bearing, and the right-handed worm (7) is key-connected to the one-way shaft (12); the inner surface of the housing (8) is provided with right-handed spiral internal teeth and left-handed spiral internal teeth; the right-handed worm (7) is connected to the left-handed worm (10) through a flat thrust ball bearing (9); the left-handed worm (10) is connected to the one-way shaft (12) through a tandem bearing (11); the one-way shaft (12) is welded to the lower one-way bearing (15), and the left-handed worm (10) is welded to the upper one-way bearing (14); the lower one-way bearing (15) is welded to the connecting shaft (16), and the upper one-way bearing (14) is welded to the connecting shaft (16); the connecting shaft (16) is spline-mated with the lower sub (18); the lower sub (18) is axially limited to the housing (8) through the axial limiting bearing (19) and the lower end cap (20); two connecting sleeves (1) are provided, and the inner surface of the connecting sleeve (1) is provided with a boss; the connecting rod valve (2) is provided with a limiting groove, and an upper limiting ring and a lower limiting ring are arranged in the limiting groove; the limiting ball (3) is controlled by a locking mechanism in the limiting cover (4).

2. The all-metal positive displacement downhole motor according to claim 1, wherein: A sealing ring is used to seal between the piston (6) and the housing (8), the inner surface of the housing (8) is surface-treated, and an oil injection hole is provided at the outer surface of the housing (8) corresponding to the right-handed spiral internal teeth and the left-handed spiral internal teeth.

3. The all-metal positive displacement downhole motor according to claim 1, wherein: There is a radial clearance between the left-handed worm (10) and the one-way shaft (12) without interference; there is a radial clearance between the left-handed worm (10) and the upper end cap (13).

4. The all-metal positive displacement downhole motor according to claim 1, wherein: The upper one-way bearing (14) and the lower one-way bearing (15) are sequentially installed in the inner hole of the connecting shaft (16); there is an axial clearance between the upper one-way bearing (14) and the lower one-way bearing (15) in the clockwise direction.

5. The all-metal positive displacement downhole motor according to claim 1, wherein: A spring (17) is provided at the shaft end of the connecting shaft (16) and the spring hole of the lower sub; the upper end of the spring (17) is welded to the lower surface of the connecting shaft (16), and the lower end of the spring (17) is welded to the upper surface of the spring hole of the lower sub (18).

6. The all-metal positive displacement downhole motor according to claim 1, characterized in that: The connecting shaft (16) axially moves in the inner hole formed by the lower joint (18) and the upper end cover (13), and the connecting shaft (16) axially moves downward and rotates under the thrust of the upper one-way bearing (14) and the lower one-way bearing (15); the upper end cover (13) and the lower joint (18) are connected by bolts.

7. The all-metal positive displacement downhole motor according to claim 1, wherein: A clearance fit is provided between the lower joint (18) and the housing (8), allowing relative rotation.

8. The all-metal positive-displacement downhole motor according to claim 1, wherein: Connecting sleeves (1) and lower joints (18) are respectively arranged at the upper and lower ends of the all-metal positive displacement downhole motor, and the connecting sleeves (1) and the lower joints (18) are respectively connected to oil drilling tools.

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