A friction and wear simulation test bench for drill pipe threaded joints in turbid seabed environments

Abstract

The present invention discloses a friction and wear simulation test bench for drill pipe threaded joints in a turbid seabed environment, comprising a bracket, an oil cylinder, an upper test piece, a lower test piece, a second motor, a third motor, a stirring rod, a seawater turbidity sensor, and a test tank. The bracket is provided with an oil cylinder and a test tank, the piston rod of the oil cylinder being connected to the second motor, a speed sensor being installed on the bottom surface of the second motor, the speed sensor facing the output shaft of the second motor, the output shaft of the second motor being connected to the upper end of a torque limiter, the lower end of the torque limiter being connected to the upper end of the upper test piece, the lower end surface of the upper test piece being engaged with the upper end surface of the lower test piece when the main shaft is loaded, the lower test piece being mounted on a base, the base being mounted on the torque sensor, a plurality of stirring rods being installed on both sides of the test tank, each stirring rod being connected to a third motor. The present invention has a simple structure and is easy to operate. By making and breaking the drill pipe threaded joint test piece, the friction and wear conditions of the drill pipe joint thread surface obtained are closer to those under actual working conditions, and the tribological properties and friction and wear mechanisms of the drill pipe threaded joint in a turbid seawater environment can be better explored.

Description

Technical Field

[0001] The invention belongs to the field of friction and wear test equipment, and in particular relates to a friction and wear simulation test bench for drill pipe threaded joints in a turbid seabed environment. Background Art

[0002] During subsea geological drilling operations using deep-sea drilling rigs, the coring drill bits inevitably disturb the seafloor sediments. Disturbed seafloor sediments become suspended around the deep-sea drilling rig, where they easily adhere to the threaded joints of the drill pipe. When additional drill pipes are added to the active drill pipe to increase drilling depth, the lower threaded joint of the active drill pipe must be threaded together with the upper threaded joint of the lower drill pipe. Because sediment adheres to both threaded joints, this can accelerate friction and wear, reducing the service life of the drill pipe and the reliability of the threaded joint. Currently, there are no reported experimental methods or technical approaches to studying the effects of seafloor sediment on the friction and wear properties of drill pipe threaded joints. Furthermore, due to the complex stress conditions of drill pipe threaded joints, existing pin-on-disc and ball-on-disc models fail to effectively simulate the actual operating conditions of drill pipe threaded joints in turbid seawater. Therefore, it is urgent to develop a friction and wear simulation test bench for drill pipe threaded joints in a turbid seabed environment to explore the friction and wear conditions of drill pipe threaded joints in a turbid seabed environment. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a turbid seabed environment drill pipe threaded joint friction and wear simulation test bench with a simple structure and easy operation. By making and breaking out the drill pipe threaded joint, the friction and wear conditions of the drill pipe joint thread surface can be obtained. The problem that the friction and wear testing machine in the existing technology cannot well simulate the actual friction conditions of the drill pipe threaded joint in turbid seawater can be solved. The tribological properties and friction and wear mechanism of the drill pipe threaded joint in turbid seawater environment can be better explored.

[0004] The technical solution adopted by the present invention is: a friction and wear simulation test bench for drill pipe threaded joints in a turbid seabed environment, comprising a bracket, an oil cylinder, a displacement sensor, a speed sensor, a torque sensor, a torque limiter, an upper test piece, a lower test piece, a second motor, a third motor, a stirring rod, a seawater turbidity sensor, a test tank and a control device;

[0005] An oil cylinder and a test tank are installed on the bracket, and the oil cylinder is located directly above the test tank; the piston rod of the oil cylinder is connected to the second motor, and the axis of the oil cylinder is parallel to the axis of the output shaft of the second motor; a displacement sensor is installed on the bottom of the oil cylinder, and a speed sensor is installed on the bottom of the second motor, and the speed sensor faces the output shaft of the second motor; the output shaft of the second motor is connected to the upper end of the torque limiter, and the lower end of the torque limiter is connected to the upper end of the upper test piece, and the lower end of the upper test piece is threadedly connected to the upper end of the lower test piece when the main shaft is loaded; the lower test piece is installed on the base, and the base is installed on the torque sensor, and the torque sensor is fixed on the bottom plate of the test tank; the seawater turbidity sensor is placed in the seawater in the test tank; a number of stirring rods are installed on both sides of the test tank, and each stirring rod is connected to a third motor; the control device is respectively connected to the displacement sensor, the speed sensor, the seawater turbidity sensor, the torque sensor, the second motor and the third motor.

[0006] Preferably, the bracket includes a base plate, a column and a cantilever beam, the column is vertically installed on the base plate, the top of the column is provided with a motor mounting seat, and the first motor is installed on the motor mounting seat; the cantilever beam is provided with a guide hole and a threaded hole, the cantilever beam is sleeved on the column through the guide hole, the output shaft of the first motor is connected to the screw, and the screw cooperates with the threaded hole; the oil cylinder is fixedly installed on the cantilever beam, and the first motor is electrically connected to the control device.

[0007] Preferably, it also includes a working electrode, a reference electrode and a counter electrode; the working electrode is connected to the lower test piece, the reference electrode and the counter electrode extend into the seawater in the test tank, and the working electrode, the reference electrode and the counter electrode are all connected to the electrochemical workstation through wires.

[0008] Preferably, the test tank is a rectangular box with an open top, and the bottom of the two side walls of the test tank are provided with hanging ears, which are fixed to the bracket by screws; the top of the two side walls of the test tank are symmetrically provided with cover plates, the third motor is installed on the cover plates, and the stirring rod is set vertically.

[0009] Preferably, the stirring rod includes a round rod and two groups of rectangular blades; the two groups of rectangular blades are installed on the round rod, and each group of rectangular blades is located at the same height on the round rod; each group of rectangular blades includes two rectangular blades, and the two groups of blades are projected perpendicular to each other in the radial direction of the round rod, and there is an inclination angle between the rectangular blades and the horizontal plane.

[0010] Preferably, the control device includes a displacement display, a speed display, a turbidity display, a torque display, a cylinder action module, a speed regulator, an acquisition control module and a digital display module. The acquisition control module is electrically connected to the digital display module, and the acquisition control module is respectively connected to the first motor, the speed regulator, the displacement display, the speed display, the turbidity display, and the torque display; the speed regulator is connected to the second motor and the third motor; the displacement display, the speed display, the turbidity display, and the torque display are respectively electrically connected to the displacement sensor, the speed sensor, the seawater turbidity sensor, and the torque sensor.

[0011] Preferably, the cylinder action module includes a cylinder motor, a hydraulic pump, an overflow valve, a pressure gauge, and a three-position four-way reversing valve. The rod chamber and the rodless chamber of the cylinder are respectively connected to the A port and the B port of the three-position four-way reversing valve; the outlet of the hydraulic pump is connected to the P port of the three-position four-way reversing valve, and the T port of the three-position four-way reversing valve and the inlet of the hydraulic pump are respectively connected to the oil tank; the input shaft of the hydraulic pump is connected to the output shaft of the cylinder motor; the outlet of the hydraulic pump is connected to the P port of the three-position four-way reversing valve through an overflow pipe to connect to the oil tank, and an overflow valve is provided on the overflow pipe, and a pressure gauge is provided on the pipe from the outlet of the hydraulic pump to the P port of the three-position four-way reversing valve; the cylinder motor is electrically connected to the control device.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1. The present invention has a simple structure. Seawater and seabed sediments are added to the test tank through the opening above the tank. The stirring rods arranged on both sides are used for stirring, which can simulate the turbid seawater environment when the seabed is disturbed by drilling. The friction pair is set as the friction pair of the drill pipe threaded joint, which can well simulate the actual working conditions of the drill pipe threaded joint in the turbid seawater environment and is easy to operate.

[0014] 2. The test tank of the present invention is provided with stirring rods on both sides. The stirring rods are provided with two sets of rectangular blades, and the rectangular blades have a certain deflection angle in the horizontal direction. Through the stirring of the two stirring rods, multi-layer vortices can be formed in the test tank, which avoids the occurrence of stirring dead zones to the greatest extent, improves the stirring efficiency, makes the seabed sediments dispersed more evenly, and can simulate a relatively stable turbid seawater environment.

[0015] 3. The oil cylinder action module of the present invention can control the up and down movement of the second motor, providing displacement space for the make-up and tightening stroke of the drill pipe female threaded joint test piece, facilitating the test piece to smoothly complete the make-up action of the drill pipe threaded joint, thereby improving work efficiency.

[0016] 4. The present invention sets a torque limiter between the upper test piece and the second motor output shaft, which can accurately and quickly disconnect the torque transmission between the second motor output shaft and the upper test piece when the torque reaches the set value, effectively reducing the error caused by the untimely stopping of the second motor output shaft, so that the upper torque is more accurately controlled.

[0017] 5. The present invention can be used to explore the friction and wear behavior and friction and wear mechanism of drill pipe threaded joints in turbid seawater, thereby finding a more optimal drill pipe threaded joint pairing scheme for seabed coring, thereby improving the efficiency and reliability of deep-sea drilling equipment, which has important practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention.

[0019] Figure 2 It is a schematic diagram of the lower test piece installation structure of the present invention.

[0020] Figure 3 It is a schematic diagram of the control system structure of the present invention.

[0021] Figure 4 It is the oil circuit wiring diagram of the present invention.

[0022] Figure 5 It is a circuit principle diagram of the control system of the present invention.

[0023] Figure 6 It is a control principle diagram of the relay of the control system of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be described clearly and completely below with reference to the accompanying drawings.

[0025] like Figure 1 、 2 As shown, the present invention includes a bracket 1, a cylinder 5, a displacement sensor 7, a speed sensor 8, a torque sensor 13, a torque limiter 9, a working electrode 17, a reference electrode 18, a counter electrode 19, an upper test piece 10, a lower test piece 11, a first motor 2, a second motor 6, a third motor 15, a stirring rod 16, a seawater turbidity sensor 14, a test tank 25 and a control device.

[0026] The bracket 1 comprises a base plate, a column, and a cantilever beam. The column is vertically mounted on the base plate. A motor mount is provided at the top of the column, on which a first motor 2 is mounted. The cantilever beam is provided with guide holes and threaded holes, through which the cantilever beam is mounted on the column. The output shaft of the first motor is connected to a screw 3, which engages with the threaded hole. Rotation of the first motor 2 drives the screw 3, thereby moving the cantilever beam up and down along the column, thereby adjusting the height of the cantilever beam.

[0027] The oil cylinder 5 is fixedly mounted on the cantilever beam, and the test tank 25 is mounted on the bottom plate, directly below the oil cylinder 5. The test tank 25 is a rectangular box with an open top. The bottom of the two side walls of the test tank 25 are provided with hanging ears, which are fixed to the bottom plate of the bracket by screws. Cover plates are symmetrically arranged on the top of the two side walls of the test tank, and the third motor 15 is mounted on the cover plates. The output shaft of the third motor 15 is connected to the stirring rod. The stirring rod 16 is located in the test tank 25, and the stirring rod 16 is vertically arranged. The third motor 15 drives the stirring rod 16 to rotate to stir the seawater in the test tank 25. The stirring rod 16 includes a round rod and two groups of rectangular blades; the two groups of rectangular blades are mounted on the round rod, and each group of rectangular blades is located at the same height on the round rod; each group of rectangular blades includes two rectangular blades, and the projections of the two groups of blades are perpendicular to each other in the radial direction of the round rod, and there is an inclination angle between the rectangular blades and the horizontal plane.

[0028] The piston rod of the oil cylinder 5 is connected to the second motor 6. The axis of the oil cylinder 5 is parallel to the axis of the output shaft of the second motor 6 and both are arranged vertically. A displacement sensor is mounted on the bottom surface of the oil cylinder 5, and a speed sensor 7 is mounted on the bottom surface of the second motor 6, facing the output shaft of the second motor 6. The output shaft of the second motor 6 is connected to the upper end of the torque limiter 8, the lower end of which is connected to the upper end of the upper test piece 10. The lower end of the upper test piece 10 is threadedly connected to the upper end of the lower test piece 11 when the main shaft is loaded. The lower end of the upper test piece has a female drill pipe threaded joint, and the upper end of the lower test piece has a male drill pipe threaded joint. The lower test piece 11 is mounted on a base 12, which is mounted on a torque sensor 13. The torque sensor 13 is fixed to the bottom plate of the test tank 25. The test tank 25 is filled with seawater, and the seawater exceeds the upper end surface of the upper test piece 11 when the shackle is in place. A seawater turbidity sensor 14 is placed in the seawater in the test tank. The input port of speed display 22 is connected to speed sensor 7; the torque display 24 is connected to torque sensor 13; and the input port of turbidity display 23 is connected to seawater turbidity sensor 14. Working electrode 17 is connected to the lower specimen, while reference electrode 18 and counter electrode 19 extend into the seawater within the test tank. These electrodes are all connected to electrochemical workstation 20 via wires.

[0029] like Figure 3 As shown, the control device includes a displacement display, a speed display, a turbidity display, a torque display, a cylinder action module, a speed regulator, an acquisition control module and a digital display module. The acquisition control module is electrically connected to the digital display module, and the acquisition control module is respectively connected to the first motor, the speed regulator, the displacement display, the speed display, the turbidity display, and the torque display; the speed regulator is connected to the second motor and the third motor; the displacement display, the speed display, the turbidity display, and the torque display are respectively electrically connected to the displacement sensor, the speed sensor, the seawater turbidity sensor, and the torque sensor.

[0030] like Figure 4 As shown, the cylinder actuation module includes a cylinder motor 28, a hydraulic pump 27, a relief valve 30, a pressure gauge 31, and a three-position, four-way directional valve 26. The rod chamber and rodless chamber of the cylinder 5 are connected to ports A and B of the three-position, four-way directional valve, respectively. The outlet of the hydraulic pump 27 is connected to port P of the three-position, four-way directional valve 26, while port T of the three-position, four-way directional valve 26 and the inlet of the hydraulic pump are connected to the oil tank 29. The input shaft of the hydraulic pump 27 is connected to the output shaft of the cylinder motor 28. The pipe connecting the outlet of the hydraulic pump 27 to port P of the three-position, four-way directional valve 26 is connected to the oil tank via an overflow pipe, which is equipped with a relief valve 30. The pipe connecting the outlet of the hydraulic pump 27 to port P of the three-position, four-way directional valve is equipped with a pressure gauge 31. The cylinder motor 28 is electrically connected to the control device.

[0031] The operating principle of the present invention is as follows: When in use, the present invention first closes switch SB2, energizing relay KM and closing its normally open contact, thereby energizing the entire control circuit. Then, switch SB4 is closed, energizing relay KA1 and closing its normally open contact, enabling forward rotation of first motor 2. This activates first motor 2 to control the lowering of cantilever 4, thereby adjusting the position of upper test piece 10. When upper test piece 10 approaches lower test piece 11, normally closed switch SB3 is opened, de-energizing relay KA1 and opening its normally open contact, thereby shutting off first motor 2. The test slot 25 is then fine-tuned to align upper test piece 10 with lower test piece 11. After alignment, the screws on the mounting ears of test slot 25 are tightened to secure test slot 25 to the bracket base. Then start each sensor, add seawater and seabed sediment in appropriate proportions through the opening above the test tank 25, use the speed regulator B to control the rotation of the third motor 15, and the third motor 15 drives the stirring rod 16 to rotate, so that the seabed sediment is fully mixed with the seawater. After observing that the seabed sediment and seawater are fully mixed and stable through the sea turbidity display 23, close the switch SB7, so that the relay KA3 is energized, and its normally open contact is closed, then the cylinder motor 28 is started, and then close the switch SB9, so that the relay KA4 is energized, and its normally open contact is closed, then Figure 4Electromagnet 1YA of the middle three-position four-way directional valve 26 is energized, extending cylinder 5. Cylinder 5 is then used to adjust the axial position of upper test piece 10, pressing the lower end face of upper test piece 10 against the upper end face of lower test piece 11. Speed ​​regulator A then controls the second motor 6 to rotate forward. This second motor 6, through torque limiter 9, drives upper test piece 10 to complete the make-up of the drill pipe threaded joint. The speed and axial tightening stroke of upper test piece 10 can be observed via speed display 22 and displacement display 21. When the set torque is reached, torque limiter 9 automatically disconnects the torque transmission between second motor 6 and upper test piece 10, ensuring precise control of the make-up torque of the drill pipe threaded joint. The torque is transmitted to the torque sensor 13 through the upper test piece 10, the lower test piece 11 and the base 12, so that the actual tightening torque of the drill pipe threaded joint test piece can be observed on the torque display 24. After the tightening is completed, the speed regulator A is used to control the second motor 6 to stop rotating, and the normally closed switch SB8 is disconnected to cut off the power of the relay KA4 and open its normally open contact. Figure 4 The electromagnet 1YA of the middle three-position four-way valve is powered off, and the oil cylinder 5 stops extending. After the main shaft stops rotating, the speed regulator A is used again to control the second motor 6 to reverse, and the switch SB10 is closed to energize the relay KA5, and its normally open contact is closed. Figure 4 When electromagnet 2YA of the middle three-position four-way valve is energized, cylinder 5 contracts, pulling second motor 6 upward. Second motor 6 rotates in the opposite direction, driving upper test piece 10 through torque limiter 9 to complete the breakout of the drill pipe threaded joint. The breakout speed of upper test piece 10 can be observed through speed display 22. The torque is transmitted to torque sensor 13 through upper test piece 10, lower test piece 11, and base 12, allowing the breakout torque of the drill pipe threaded joint specimen to be observed on torque display 24. After the test is completed, normally closed switch SB1 is disconnected, de-energizing relay KM. Its normally open contacts open, de-energizing the entire circuit. The process of making and breaking drill pipe threads causes friction and wear on the thread surface. By repeatedly making and breaking drill pipe threaded joint specimens, the condition of the drill pipe threaded joint after repeated friction and wear in turbid seawater environments can be determined, accelerating research and shortening the research cycle.

Claims

1. A friction and wear simulation test bench for drill pipe threaded joints in a turbid seabed environment, comprising a bracket, a cylinder, a displacement sensor, a speed sensor, a torque sensor, a torque limiter, an upper test piece, a lower test piece, a second motor, a third motor, a stirring rod, a seawater turbidity sensor, a test tank, and a control device; characterized by: An oil cylinder and a test tank are installed on the bracket, and the oil cylinder is located directly above the test tank; the piston rod of the oil cylinder is connected to the second motor, and the axis of the oil cylinder is parallel to the axis of the output shaft of the second motor; a displacement sensor is installed on the bottom of the oil cylinder, and a speed sensor is installed on the bottom of the second motor, and the speed sensor faces the output shaft of the second motor; the output shaft of the second motor is connected to the upper end of the torque limiter, and the lower end of the torque limiter is connected to the upper end of the upper test piece, and the lower end of the upper test piece is threadedly connected to the upper end of the lower test piece when the main shaft is loaded; the lower test piece is installed on the base, and the base is installed on the torque sensor, and the torque sensor is fixed on the bottom plate of the test tank; the seawater turbidity sensor is placed in the seawater in the test tank; a number of stirring rods are installed on both sides of the test tank, and each stirring rod is connected to a third motor; the control device is respectively connected to the displacement sensor, the speed sensor, the seawater turbidity sensor, the torque sensor, the second motor and the third motor.

2. The turbid seabed environment drill pipe threaded joint friction and wear simulation test bench according to claim 1 is characterized by: The bracket includes a base plate, a column and a cantilever beam. The column is vertically installed on the base plate. A motor mounting seat is provided at the top of the column, and a first motor is installed on the motor mounting seat. The cantilever beam is provided with a guide hole and a threaded hole. The cantilever beam is sleeved on the column through the guide hole. The output shaft of the first motor is connected to a screw rod, and the screw rod cooperates with the threaded hole. The oil cylinder is fixedly installed on the cantilever beam, and the first motor is electrically connected to the control device.

3. The friction and wear simulation test bench for drill pipe threaded joints in turbid seabed environments according to claim 1 is characterized by: It also includes a working electrode, a reference electrode and a counter electrode; the working electrode is connected to the lower test piece, the reference electrode and the counter electrode are extended into the seawater in the test tank, and the working electrode, the reference electrode and the counter electrode are all connected to the electrochemical workstation through wires.

4. The friction and wear simulation test bench for drill pipe threaded joints in turbid seabed environments according to claim 1 is characterized by: The test tank is a rectangular box with an open top. The bottom of the two side walls of the test tank are provided with hanging ears, which are fixed to the bracket by screws; the top of the two side walls of the test tank are symmetrically provided with cover plates, the third motor is installed on the cover plates, and the stirring rod is set vertically.

5. The friction and wear simulation test bench for drill pipe threaded joints in turbid seabed environments according to claim 1 is characterized by: The stirring rod includes a round rod and two groups of rectangular blades; the two groups of rectangular blades are installed on the round rod, and each group of rectangular blades is located at the same height on the round rod; each group of rectangular blades includes two rectangular blades, and the two groups of blades are projected perpendicular to each other in the radial direction of the round rod, and there is an inclination angle between the rectangular blades and the horizontal plane.

6. The friction and wear simulation test bench for drill pipe threaded joints in turbid seabed environments according to claim 2 is characterized by: The control device includes a displacement display, a speed display, a turbidity display, a torque display, a cylinder action module, a speed regulator, an acquisition control module and a digital display module. The acquisition control module is electrically connected to the digital display module. The acquisition control module is respectively connected to the first motor, the speed regulator, the displacement display, the speed display, the turbidity display and the torque display; the speed regulator is connected to the second motor and the third motor; the displacement display, the speed display, the turbidity display and the torque display are respectively electrically connected to the displacement sensor, the speed sensor, the seawater turbidity sensor and the torque sensor.

7. The friction and wear simulation test bench for drill pipe threaded joints in turbid seabed environments according to claim 6 is characterized by: The oil cylinder action module includes an oil cylinder motor, a hydraulic pump, an overflow valve, a pressure gauge and a three-position four-way reversing valve. The rod chamber and the rodless chamber of the oil cylinder are respectively connected to the A port and the B port of the three-position four-way reversing valve; the outlet of the hydraulic pump is connected to the P port of the three-position four-way reversing valve, and the T port of the three-position four-way reversing valve and the inlet of the hydraulic pump are respectively connected to the oil tank; the input shaft of the hydraulic pump is connected to the output shaft of the oil cylinder motor; the outlet of the hydraulic pump is connected to the P port of the three-position four-way reversing valve through an overflow pipe to connect to the oil tank, and an overflow valve is provided on the overflow pipe. The outlet of the hydraulic pump is connected to the P port of the three-position four-way reversing valve through an overflow pipe to connect to the oil tank, and a pressure gauge is provided on the pipe. The oil cylinder motor is electrically connected to the control device.

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