Testing device for evaluating PDC (Polycrystalline Diamond Compact) single-tooth high-frequency torsional vibration failure damage and use method
By designing a PDC single-tooth high-frequency torsional vibration test device, combined with FEM simulation and multi-sensor monitoring, the problem of the failure mechanism of PDC cutting teeth under high-frequency torsional vibration is solved, which improves drilling efficiency and equipment durability and reduces drilling costs.
Patent Information
- Application Number
- CN202510714657.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-07-18
AI Technical Summary
The prior art has failed to effectively evaluate the mechanism of failure of PDC single teeth under high-frequency torsional vibration, especially in hard rock formations, and the fracture problem of cutting teeth has not received enough attention, resulting in low failure efficiency of PDC drill bits and increasing drilling costs and risks.
A test device including a device bearing system, a loading system, a rotation control system, a high-frequency torsional vibration excitation system and a real-time monitoring system was designed. The high-frequency torsional vibration downhole was simulated through FEM software, and a variety of sensors were used to monitor the failure of PDC cutting teeth to realize cutting test and damage assessment under high-frequency torsional vibration.
The failure mechanism of PDC cutting teeth under high-frequency torsional vibration was accurately explored, providing a theoretical basis for scientific design of impact-resistant PDC cutting teeth, reducing drilling costs, improving drilling efficiency, and filling the technical gap in high-frequency torsional vibration research.
Smart Images
Figure CN120333741A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of oil drilling equipment, and in particular to a test device for evaluating failure damage of a PDC single tooth by high frequency torsional vibration and a use method thereof. Background Art
[0002] As the pillar of the global energy system, the oil industry will remain the main energy source in the fields of transportation, chemical industry, etc. in the short term. It is especially irreplaceable in scenarios that are difficult to electrify, such as aviation and shipping. In the oil industry, drilling is the most costly and risky link in oil and gas development, and its efficiency directly affects the economic feasibility of resource extraction. As exploration advances into ultra-deep and complex formations, efficient drilling tools become the key.
[0003] High-frequency torsional vibration is a self-excited vibration phenomenon triggered by the interaction between the drill bit and the rock. It poses a serious threat to drilling tools, engineering efficiency and the economy of the oil industry, and causes fractures in the drill string and drill bit materials through periodic shear stress. The economic cost and operational risks surge, and the frequent drilling and tool replacement increase the drilling cost. PDC drill bits have high hardness, wear resistance and impact resistance. According to statistics, 90% of the footage in the world relies on PDC drill bits, making them the preferred tool for deep well drilling, and significantly shortening the drilling cycle in hard rock formations. High-frequency torsional vibration accelerates the failure of PDC drill bits due to high-frequency impact, and more than 70% of the main causes of PDC drill bit failure are caused by damage to the PDC cutting teeth.
[0004] Although the existing PDC single-tooth cutting experimental device has made progress in cutting parameter control and complex working condition reproduction, it has given little consideration to the generation mechanism of downhole high-frequency torsional vibration and its impact on the dynamic damage mechanism of the cutter; high-frequency torsional vibration, as the core hazard source in deep well hard rock drilling, will directly lead to the failure of PDC cutters; the existing failure quantification of PDC cutters only considers the evaluation and grading of cutter wear, while the failure form of PDC cutters is not only wear, but also fractures in hard rock formations. The evaluation and grading of fractures of PDC cutters is also of great significance; therefore, there is an urgent need for a test device and a method for using it to evaluate the failure damage of a single PDC tooth with high-frequency torsional vibration, so as to solve the above technical problems. Summary of the invention
[0005] The present invention aims to solve the above-mentioned problems, thereby providing a test device and a method for using it for evaluating the failure damage of a single PDC tooth due to high-frequency torsional vibration, filling the technical gap in the study of the stress failure of PDC cutting teeth under high-frequency torsional vibration, accurately exploring the failure mechanism of PDC cutting teeth under the action of high-frequency torsional vibration, providing a theoretical basis for the scientific design and optimization of impact-resistant PDC cutting teeth, and providing a core experimental platform for the research and development of high-frequency vibration suppression technology, which is of strategic significance for breaking through the bottleneck of ultra-deep oil and gas resource development.
[0006] To solve the above problems, the technical solution adopted by the present invention is as follows: An experimental device for evaluating the failure damage of high-frequency torsional vibration of a single PDC tooth, comprising a device bearing system, a loading system, a rotation control system, a high-frequency torsional vibration excitation system, and a real-time monitoring system; the device bearing system includes a base disposed on a horizontal ground, and four support frames are arranged on the upper surface of the base, the four support frames are spaced apart from each other and symmetrically arranged in pairs, and a loading frame parallel to the base is commonly arranged at the upper ends of the four support frames; the loading system is disposed on the loading frame, including a control panel disposed on the loading frame, a hydraulic chamber is arranged in the center of the loading frame, a loading pump is connected to the hydraulic chamber, a liquid injected into the hydraulic chamber is arranged in the loading pump, a piston reciprocating in the height direction is arranged in the hydraulic chamber, and a loading rod extending downward out of the hydraulic chamber is vertically fixed to the lower bottom surface of the piston; the rotation control system is connected to the loading rod, including a system housing connected to the loading rod, a rotation motor is arranged on the system housing, an output end of the rotation motor extends into the system housing, a rotation shaft is arranged on the lower bottom surface of the system housing, an upper end of the rotation shaft vertically penetrates the lower bottom surface of the system housing and is in transmission connection with the output end of the rotation motor, a rotating disc is connected to the lower end of the rotation shaft, a single-tooth clamp is arranged on the lower bottom surface of the rotating disc, and a PDC cutting tooth is installed on the single-tooth clamp; the high-frequency torsional vibration excitation system is disposed on the upper surface of the base, including a rock sample turntable arranged at the center of the upper surface of the base, a rock sample corresponding to the PDC cutting tooth is placed on the rock sample turntable, a servo motor is arranged on the front side surface of the base, a driver connected to the servo motor is arranged outside the base, and a control system is commonly connected to the servo motor and the driver; the real-time monitoring system is connected to the bearing system and the rotation control system.
[0007] Further, the real-time monitoring system includes a high-speed camera for recording the real-time state of the cutting tooth cutting the rock sample, the high-speed camera is arranged on any support frame and corresponds to the rock sample and the cutting tooth; a torque sensor arranged on the upper surface of the rotating disc and a torque sensor arranged on the rock sample turntable; a triaxial acceleration sensor arranged in the single-tooth clamp and a load sensor arranged in the single-tooth clamp.
[0008] Further, the control system includes control logic programming, PID parameter tuning, resonance suppression, and FEM software; and the control logic programming, PID parameter tuning, and resonance suppression cooperate with each other to enable the high-frequency torsional vibration excitation system to generate a vibration frequency.
[0009] Further, the rock sample turntable includes a turntable fixed at the center of the upper surface of the base, the turntable is connected to the servo motor, a square rotating shaft is fixed at the center of the upper surface of the turntable, a square hole is arranged at the bottom of the rock sample, the square hole is adapted to the square rotating shaft, and the rock sample is installed on the square rotating shaft through the square hole.
[0010] Further, the control panel is connected to the loading pump and the rotating motor.
[0011] Further, a counterweight block adapted to the PDC cutting teeth and the single-tooth fixture is fixedly connected to the lower bottom surface of the rotating disc; the single-tooth fixture includes two vertical connecting plates vertically fixed on the lower bottom surface of the rotating disc, the two vertical connecting plates are spaced apart from each other and parallel to each other, through holes facing each other are provided at the lower ends of the two vertical connecting plates, a connecting rod is commonly installed on the through holes, the PDC cutting teeth are installed on the connecting rod and located between the two vertical connecting plates, fastening nuts threadedly connected to the connecting rod are provided on the outer sides of the two vertical connecting plates, and an adjusting nut is clamped between the PDC cutting teeth and one of the vertical connecting plates.
[0012] A method for using a test device for evaluating the high-frequency torsional vibration failure damage of a single PDC tooth includes a single-tooth cutting test method for high-frequency torsional vibration and a method for quantitatively evaluating the damage of a single PDC tooth.
[0013] Further, the single-tooth cutting test method for high-frequency torsional vibration includes the following steps: S1. Design an experimental scheme, perform modeling and simulation on the bottomhole assembly through FEM software, obtain the vibration frequency and amplitude through modal analysis and harmonic response analysis, and determine the drilling parameters required for the test; S2. Fix the PDC cutting teeth in the single-tooth fixture, then adjust the back rake angle by adjusting the single-tooth fixture, fix it with a nut after adjustment, and place the rock sample in the turntable after processing the rock sample; S3. Then, operate the control panel to start loading, start the high-speed camera, adjust the position of the high-speed camera so that the cutting area of the rock sample appears within the field of view of the high-speed camera, and check whether the other components are reacting normally; S4. Then, start the high-frequency torsional vibration excitation system, input the vibration frequency and amplitude to make the rock sample generate corresponding high-frequency torsional vibration, start the rotation control system to make the PDC cutting teeth start to rotate around the rotation axis, after the rotation speed of the rotation control system is constant, start the loading system, apply a load to the PDC cutting teeth through the loading frame, and make the PDC cutting teeth cut along the rock sample, and its cutting path realizes the cutting of the rock sample by the cutting teeth under high-frequency torsional vibration; S5. After the cutting process is completed, stop the axial loading of the loading frame, raise the rotation control system, stop the rotation control system and the high-frequency torsional vibration excitation system, turn off the testing machine, and record and save the measurement data.
[0014] Furthermore, the method for quantitatively evaluating the damage of a single PDC tooth includes a failure life model of a PDC cutting tooth under high-frequency torsional vibration; the method for quantitatively evaluating the damage of a single PDC tooth based on the failure life model of a PDC cutting tooth under high-frequency torsional vibration includes the following steps: S1. Under high-frequency torsional vibration of the PDC cutting tooth, the damage amount of the PDC cutting tooth is related to the applied drilling pressure, rotational speed, vibration frequency, and amplitude. Using the failure life model of the PDC cutting tooth under high-frequency torsional vibration and based on the existing test conditions, predict the damage amount of the cutting tooth; S2. Wipe the PDC cutting tooth after the test clean, and then take a photo of the PDC cutting tooth through a high-definition camera to analyze the failure type of the PDC cutting tooth; S3. Then, use image data processing software to evaluate and grade the failure damage amount of the PDC cutting tooth, quantitatively analyze the damage amount of the PDC cutting tooth, obtain the actual damage amount of the PDC cutting tooth under high-frequency torsional vibration, compare it with the predicted damage amount of the PDC cutting tooth, and further predict the failure life of the PDC cutting tooth under high-frequency torsional vibration.
[0015] Furthermore, the failure life model of the PDC cutting tooth under high-frequency torsional vibration includes ; through the failure life model of the PDC cutting tooth under high-frequency torsional vibration, it is determined that within a specified time, under high-frequency torsional vibration of the PDC cutting tooth, the damage amount of the PDC cutting tooth is related to the applied drilling pressure, rotational speed, vibration frequency, and amplitude; among them, is the damage amount of the PDC cutting tooth; is the drilling pressure, with the unit of kN; is the rotational speed, with the unit of r / min; is the vibration frequency, with the unit of Hz; is the amplitude, with the unit of m / s²; I1 - I4 are all dimensionless coefficients.
[0016] The present invention adopting the above technical solution, compared with the prior art, its prominent features are: The present invention fills the technical gap in the research on the force failure of PDC cutting teeth under high-frequency torsional vibration, accurately explores the failure mechanism of PDC cutting teeth under high-frequency torsional vibration, provides a theoretical basis for the scientific design and optimization of impact-resistant PDC cutting teeth, provides a core experimental platform for the research and development of high-frequency vibration suppression technology, and has strategic significance for breaking through the bottleneck of ultra-deep oil and gas resource development; In addition, according to the FEM software technology, the high-frequency torsional vibration frequency and amplitude are determined. Then, through the high-frequency torsional vibration excitation system, the working conditions of high-frequency torsional vibration occurring during actual oil bit drilling are simulated, enabling a single-tooth cutting test of PDC cutting teeth under artificially set high-frequency torsional vibration; a single-tooth cutting test can also be carried out when the high-frequency torsional vibration excitation system is turned off, and by comparing them with each other, it is more conducive to exploring the influence of high-frequency torsional vibration on PDC cutting teeth; Furthermore, by scientifically and conveniently determining the drilling parameters, single-tooth cutting rock experiments with different weights on bit and different rotational speeds can be achieved; multiple sensors are used to collect and receive data. The axial force and tangential force are recorded by pressure sensors, the vibration conditions of the cutting teeth are recorded by triaxial acceleration sensors, the torque of the cutting teeth is recorded by torque sensors, and the single-tooth cutting rock situation is dynamically recorded by high-speed cameras, which is more conducive to analyzing the failure mechanism of PDC cutting teeth under high-frequency torsional vibration; at the same time, it can also be used for rock drillability tests and abrasiveness tests, and can also explore the failure mechanism of the bit under high-frequency torsional vibration, with rich and diverse equipment functions.
[0017] The present invention conducts cutting experiments on the same batch of rock samples under different vibration frequencies, different amplitudes, and different test durations to determine coefficients. Subsequently, experiments can be carried out on rock samples of different lithologies to further improve the high-frequency torsional vibration failure life model of PDC cutting teeth. In addition, the test device of the present invention can be used to verify the high-frequency torsional vibration failure life model of PDC cutting teeth.
[0018] The present invention can realize the drilling of rock samples by PDC cutting teeth under the influence of high-frequency torsional vibration. Through the high-frequency torsional vibration excitation system, the working conditions of high-frequency torsional vibration occurring during actual oil bit drilling are simulated, and high-frequency torsional vibration with approximate vibration frequency and amplitude can be generated; by controlling the loading system and the rotation control system, single-tooth cutting rock experiments of PDC cutting teeth with different weights on bit and different rotational speeds can be achieved, and multiple parameters of the entire cutting process can be monitored in real time. The vibration conditions of PDC cutting teeth are recorded by triaxial acceleration sensors, the torque of PDC cutting teeth and the torque output by the high-frequency torsional vibration excitation system are recorded by torque sensors, and the single-tooth cutting rock situation of PDC cutting teeth is dynamically recorded by high-speed cameras. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 is a schematic diagram of the front view structure of the present invention; Figure 2 is Figure 1 a schematic diagram of the enlarged partial structure; Figure 3 is a schematic diagram of the rotational speed of the rock sample of the present invention under corresponding high-frequency torsional vibration; Figure 4 is a schematic diagram of the grading standard for the damage amount of PDC cutting teeth of the present invention; In the figure: 1, base; 2, support frame; 3, loading frame; 4, control panel; 5, loading pump; 6, hydraulic chamber; 7, piston; 8, loading rod; 9, system housing; 10, rotating motor; 11, rotating shaft; 12, rotating disk; 13, PDC cutting tooth; 14, single-tooth fixture; 15, servo motor; 16, driver; 17, rock sample turntable; 18, rock sample; 19, high-speed camera; 20, turntable; 21, square rotating shaft; 22, torque sensor; 23, triaxial acceleration sensor; 24, load sensor; 25, counterweight; 26, vertical connecting plate; 27, connecting rod; 28, fastening nut; 29, adjusting nut. Specific implementation mode
[0020] Through the following description of the embodiments, it will be more helpful for the public to understand the present invention. However, the specific embodiments given by the applicant should not be regarded as a limitation to the technical solution of the present invention. Any change in the definition of components or technical features and / or any formal rather than substantial transformation of the overall structure should be regarded as the protection scope defined by the technical solution of the present invention.
[0021] See Figures 1 to 4 As shown, the technical solution of the present invention is as follows: An experimental device for evaluating the failure damage of high-frequency torsional vibration of PDC single teeth includes a device bearing system, a loading system, a rotation control system, a high-frequency torsional vibration excitation system, and a real-time monitoring system; The device bearing system includes a base 1, the base 1 is placed on a horizontal ground, and four support frames 2 are fixed on the upper surface of the base 1. The four support frames 2 are spaced apart from each other and are symmetrically arranged in pairs. At the upper ends of the four support frames 2, a loading frame 3 parallel to the base 1 is fixedly installed together; The loading system is installed on the loading frame 3 and includes a control panel 4 installed on the loading frame 3. The control panel 4 controls the operation of the loading system and the rotation control system. A hydraulic chamber 6 is arranged in the center of the loading frame 3. A loading pump 5 is connected to the hydraulic chamber 6. The loading pump 5 is connected to the control panel 4. The loading pump 5 is provided with a liquid injected into the hydraulic chamber 6. A piston 7 that reciprocates in the height direction is arranged in the hydraulic chamber 6. A loading rod 8 extending downward out of the hydraulic chamber 6 is vertically fixed on the lower bottom surface of the piston 7. Thus, by controlling the operation of the loading pump 5 through the control panel 4, the loading pump 5 inputs the liquid into the hydraulic chamber 6 to provide power for the loading system. At the same time, the piston 7 and the loading rod 8 cooperate to transfer the liquid kinetic energy of the hydraulic chamber 6 to the rotation control system. At the same time, the control panel 4 selects the equal-pressure input of the loading pump 5, and then the drilling pressure can be selected as the loading method, and the drilling pressure is 0-50 kN; The rotation control system is connected to the loading rod 8 and includes a system housing 9 connected to the loading rod 8. A rotation motor 10 is provided on the system housing 9. The rotation motor 10 is connected to the control panel 4. The output end of the rotation motor 10 extends into the system housing 9. A rotation shaft 11 is provided on the lower bottom surface of the system housing 9. The upper end of the rotation shaft 11 vertically penetrates the lower bottom surface of the system housing 9 and is in transmission connection with the output end of the rotation motor 10. A rotation disk 12 is connected to the lower end of the rotation shaft 11. A single-tooth clamp 14 is provided on the lower bottom surface of the rotation disk 12. A PDC cutting tooth 13 is installed on the single-tooth clamp 14. The angle of the PDC cutting tooth 13 is adjusted by the single-tooth clamp 14, so as to control the cutting depth and rake angle of the PDC cutting tooth 13. Among them, the inclination angle of the single-tooth clamp 14 is 0-80°, and the cutting depth is 0.1 mm. The rotation control system transmits the axial load of the loading rod 8 to the single-tooth clamp 14 through the system housing 9, and transmits the torque of the rotation motor 10 to the PDC cutting tooth 13 through the rotation shaft 11 and the rotation disk 12 to provide the cutting speed for the PDC cutting tooth 13. At the same time, the rotation speed of the rotation motor 10 can be set through the control panel 4, so that the rotation speed of the rotation disk 12 is 0-240 r / min; The high-frequency torsional vibration excitation system is arranged on the upper surface of the base 1 and includes a rock sample turntable 17 arranged at the center of the upper surface of the base 1. The rock sample turntable 17 includes a turntable 20 fixed at the center of the upper surface of the base 1. The turntable 20 is connected to a servo motor 15. A square rotating shaft 21 is fixed at the center of the upper surface of the turntable 20. A square hole is arranged at the bottom of the rock sample 18. The square hole is adapted to the square rotating shaft 21 and the rock sample 18 is installed on the square rotating shaft 21 through the square hole. And the PDC cutting teeth 13 correspond to the rock sample 18 placed on the rock sample turntable 17. The radius of the rock sample 18 is 0.3 m and the height is 0.2 m. The square hole is arranged at the center of the bottom of the rock sample 18 and the edge length of the square hole is 0.1 m. A servo motor 15 is arranged on the front side surface of the base 1. A driver 16 connected to the servo motor 15 is arranged outside the base 1. A control system is commonly connected to the servo motor 15 and the driver 16. The servo motor 15 is a Baldor DMC and the driver 16 is a Beckhoff AX8000. The control system includes control logic programming, PID parameter tuning, resonance suppression and FEM software. And the control logic programming, PID parameter tuning and resonance suppression cooperate with each other to enable the high-frequency torsional vibration excitation system to generate a vibration frequency. The vibration frequency is 20 - 300 Hz and the amplitude is 100 - 100g. Another 0 - 240 r / min rotation speed is coordinated to simulate the high-frequency torsional vibration underground. Furthermore, the high-frequency torsional vibration is used to carry out modeling and simulation on the bottomhole assembly through FEM software, and the natural frequency and amplitude are obtained through modal analysis and harmonic response analysis. Then, the bottomhole assembly is calculated and checked through the formula. Finally, a high-frequency torsional vibration conforming to the natural frequency and amplitude is applied to the rock sample 18. In addition, the driver 16 and the servo motor 15 can be controlled by the control system to set the vibration amplitude and vibration frequency, and then the rock sample turntable 17 and the rock sample 18 start to generate high-frequency torsional vibration. While the PDC cutting teeth 13 are rotating, the rock sample 18 is also rotating in high-frequency torsional vibration. And the PDC cutting teeth 13 are also subjected to the axial load of the loading system. Finally, the PDC cutting teeth 13 realize the movement track under the influence of high-frequency torsional vibration, so that the PDC cutting teeth 13 continuously cut along the rock sample 18. The real-time monitoring system is connected to the bearing system and the rotation control system, so that the PDC cutting teeth 13 are subjected to the axial load while rotating, simulating the drilling behavior of the PDC cutting teeth 13. By controlling the high-frequency torsional vibration excitation system, the rock sample 18 generates high-frequency torsional vibration. Through the device bearing system combined with the loading system, the rotation control system and the high-frequency torsional vibration excitation system, the cutting of the rock sample 18 by the PDC cutting teeth 13 under high-frequency torsional vibration is realized.
[0022] The real-time monitoring system includes a high-speed camera 19 that records the real-time state of the cutting teeth cutting the rock sample. The high-speed camera 19 is arranged on any support frame 2 and corresponds to the rock sample and the cutting teeth. The high-speed camera 19 uses a VEO 640 high-speed camera with a resolution of 1280 x 1280, which supports high-speed photography at 3270 FPS in full frame. The real-time state of the PDC cutting teeth 13 cutting the rock sample is recorded by the high-speed camera 19; a torque sensor 22 is arranged on the upper surface of the rotating disk 12 and a torque sensor 22 is arranged on the rock sample turntable 17. The torque sensor 22 uses an HBM T40B fiber grating torque sensor 22 to measure and record the torque, and the sampling rate is greater than 3000 Hz; a triaxial acceleration sensor 23 and a load sensor 24 are arranged in the single-tooth fixture 14. The triaxial acceleration sensor 23 uses a PCB 352C33 triaxial accelerometer, the sampling rate is greater than 3000 Hz, and the vibration measurement error is 5×10-3; the load sensor 24 uses a SENS100~34CWB wireless load sensor 24. The tangential force and axial force acting on the PDC cutting teeth 13 can be obtained through the load sensor 24, and the sampling rate is greater than 3000 Hz; thus, test data is collected through the high-speed camera 19, the torque sensor 22, the triaxial acceleration sensor 23, and the load sensor 24.
[0023] A counterweight 25 adapted to the PDC cutting teeth 13 and the single-tooth fixture 14 is also fixedly connected to the lower bottom surface of the rotating disk 12; the single-tooth fixture 14 includes two vertical connecting plates 26 vertically fixed on the lower bottom surface of the rotating disk 12. The two vertical connecting plates 26 are spaced apart from each other and parallel to each other. Through holes opposite to each other are arranged at the lower ends of the two vertical connecting plates 26. A connecting rod 27 is commonly installed on the through holes. The PDC cutting teeth 13 are installed on the connecting rod 27 and located between the two vertical connecting plates 26. Tightening nuts 28 threadedly connected to the connecting rod 27 are arranged on the outer sides of the two vertical connecting plates 26, and an adjusting nut 29 is clamped between the PDC cutting teeth 13 and one of the vertical connecting plates 26.
[0024] A usage method of a test device for evaluating the high-frequency torsional vibration failure damage of a PDC single tooth includes a single-tooth cutting test method for high-frequency torsional vibration and a method for quantitatively evaluating the damage of the PDC single tooth.
[0025] The single-tooth cutting test method for high-frequency torsional vibration includes the following steps: S1. Design an experimental scheme, build a model and simulate the bottom hole assembly (BHA) through FEM software, and obtain the vibration frequency and amplitude through modal analysis and harmonic response analysis. The high-frequency torsional vibration of the bottom hole is obtained through the following method: use 3D modeling software such as UG NX or Solidwork to build a three-dimensional model of the BHA, then use FEM software such as Ansys or Abaqus for mesh generation and material definition. After completion, perform modal analysis to obtain the natural frequency and vibration mode of the drill string assembly, combine with formula verification, and then obtain the corresponding amplitude through the frequency obtained from modal analysis and harmonic response analysis. For example, the vibration frequency is 178 Hz and the amplitude is 88.7 g, and determine the drilling parameters required for the experiment. For example, the weight on bit is 10 kN, and the rotational speed of the PDC cutting tooth 13 is 90 r / min. Among them, the specific formula for the natural frequency is as follows:
[0026] In the formula, G is the shear modulus with the unit of Pa; ρ is the density of steel with the unit of m3 / kg; L is the length of the BHA with the unit of m; the modal order n = 1, 2, 3,... The specific formula for the amplitude is as follows:
[0027] In the formula, RPM is the rotational speed of the cutting tooth with the unit of r / min; ω0, n is the angular frequency under the modal order n with the unit of rad / s; the modal order n = 1, 2, 3,... S2. Fix the PDC cutting tooth 13 in the single-tooth fixture 14, and then complete the setting of the back rake angle and cutting speed of the PDC cutting tooth 13 according to the experimental scheme. Adjust the back rake angle of the PDC cutting tooth 13 by adjusting the single-tooth fixture 14, and maintain the cutting angle unchanged during the experiment by tightening the fastening nuts 28 on both sides. The cutting speed is controlled by controlling the rotational speed of the rotation control system through the control panel 4. The lithology of the rock sample 18 is granite. The size of the rock sample 18 is a radius of 0.3 m and a height of 0.2 m. A square hole is dug in the center of the bottom of the rock sample 18, and the edge length of the square hole is 0.1 m. Then place the rock sample 18 on the square rotating shaft 21. S3. Then, according to the experimental scheme, operate the control panel 4 to start loading, start the high-speed camera 19, adjust the position of the high-speed camera 19 so that the cutting area of the rock sample 18 appears within the field of view of the high-speed camera 19, and check whether the other components are reacting normally. S4. Then, start the high-frequency torsional vibration excitation system to apply high-frequency torsional vibration conforming to the same bottom-hole conditions to the rock sample 18, that is, apply high-frequency torsional vibration with the same vibration frequency and amplitude; set the lower limit of the rotational speed generated by the high-frequency torsional vibration excitation system to 0 r / min. For example, the high-frequency torsional vibration excitation system generates a rotational speed in the range of 0 - 177 r / min, and generates high-frequency torsional vibration with a vibration frequency of 177 Hz and an amplitude of 88.7 g, as Figure 3 shown; start the rotation control system to make the PDC cutting tooth 13 start to rotate around the rotating shaft 11. After the rotational speed of the rotation control system is constant, the rotational speed of the PDC cutting tooth 13 is 90 r / min. By starting the loading system, apply a load drilling pressure of 10 kN to the PDC cutting tooth 13 through the loading frame 3, so that the PDC cutting tooth 13 cuts along the rock sample 18. The cutting path of the PDC cutting tooth 13 realizes the cutting of the rock sample 18 by the PDC cutting tooth 13 under high-frequency torsional vibration, and observe the force failure process of the PDC cutting tooth 13 under high-frequency torsional vibration at its natural frequency; S5. After cutting for a corresponding duration of 10 min, after the cutting process is completed, turn off the loading pump 5, stop the axial loading of the loading frame 3, raise the rotation control system, stop the rotation control system and the high-frequency torsional vibration excitation system, record and save the measurement data, wait for the test device to stand still for five minutes, then turn off the power supply, and remove the PDC cutting tooth 13.
[0028] The method for quantitatively evaluating PDC single-tooth damage includes a failure life model of the PDC cutting tooth 13 under high-frequency torsional vibration; the method for quantitatively evaluating PDC single-tooth damage based on the failure life model of the PDC cutting tooth 13 under high-frequency torsional vibration includes the following steps: S1. Under high-frequency torsional vibration of the PDC cutting tooth 13, the damage amount of the PDC cutting tooth 13 is related to the applied drilling pressure, rotational speed, vibration frequency, and amplitude. Conduct a quantitative analysis of the PDC cutting tooth 13, use the failure life model of the PDC cutting tooth 13 under high-frequency torsional vibration, and predict the damage amount of the cutting tooth according to the existing test conditions, and then predict the failure life of the PDC cutting tooth 13 under high-frequency torsional vibration; S2. Wipe the tested PDC cutting tooth 13 clean, then place the PDC cutting tooth 13 under a high-definition camera for photographing. The photographing direction should be perpendicular to the plane of the diamond composite sheet of the PDC cutting tooth 13. Then analyze the failure type of the PDC cutting tooth 13. The failure types are divided into two categories: fracture and wear, and observe the failure interface of the PDC cutting tooth 13. The fracture failure interface morphology of the PDC cutting tooth 13 is irregular, while the wear failure interface morphology of the PDC cutting tooth 13 is approximately regular; S3. Then, use image data processing software to evaluate and grade the failure damage amount of the PDC cutting tooth 13. First, import the damage photos of the complete PDC cutting tooth 13 into the software. Use the Threshold tool to perform threshold segmentation on the damage area. Then, calculate through the Material Statistics module to obtain the number of pixels in the damage area, and further obtain the area ratio of the damage area. Subsequently, conduct a quantitative analysis of the damage amount of the PDC cutting tooth 13 to obtain the actual damage amount of the PDC cutting tooth 13 under high-frequency torsional vibration. Compare it with the predicted damage amount of the PDC cutting tooth 13 to predict the failure life of the PDC cutting tooth 13 under high-frequency torsional vibration; In addition, it also includes the standard for grading the damage amount of the PDC cutting tooth 13. Take the area ratio of the damage area as the damage amount Vd, which is divided into eight grades from 1 to 8, as Figure 4 shown; for example: if the single-tooth damage amount Vd this time is 46%, the damage grade is classified as grade 4; The high-frequency torsional vibration failure life model of the PDC cutting tooth 13 includes ; Through the high-frequency torsional vibration failure life model of the PDC cutting tooth 13, it is determined that within a specified time, under high-frequency torsional vibration, the damage amount of the PDC cutting tooth 13 is related to the applied drilling pressure, rotational speed, vibration frequency, and amplitude; among them, is the damage amount of the PDC cutting tooth 13; is the drilling pressure, with the unit of kN; is the rotational speed, with the unit of r / min; is the vibration frequency, with the unit of Hz; is the amplitude, with the unit of m / s²; I1 - I4 are all dimensionless coefficients.
[0029] The present invention fills the technical gap in the research on the force failure of PDC cutting teeth 13 under high-frequency torsional vibration, accurately explores the failure mechanism of PDC cutting teeth 13 under the action of high-frequency torsional vibration, provides a theoretical basis for the scientific design and optimization of impact-resistant PDC cutting teeth 13, provides a core experimental platform for the research and development of high-frequency vibration suppression technology, and has strategic significance for breaking through the bottleneck of ultra-deep oil and gas resource development; In addition, according to the FEM software technology, determine the high-frequency torsional vibration frequency and amplitude, and then simulate the working conditions of high-frequency torsional vibration that occur during actual oil drill bit drilling through the high-frequency torsional vibration excitation system, enabling the PDC cutting tooth 13 to achieve a single-tooth cutting test under artificially set high-frequency torsional vibration; A single-tooth cutting test can also be carried out when the high-frequency torsional vibration excitation system is turned off, and by comparing with each other, it is more conducive to exploring the influence of high-frequency torsional vibration on the PDC cutting tooth 13; Furthermore, by scientifically and conveniently determining the drilling parameters, single-tooth rock cutting experiments with different weights on bit (WOB) and different rotary speeds can be achieved. Multiple sensors collect and receive data. The axial force and tangential force are recorded by the pressure sensor, the vibration condition of the cutting tooth is recorded by the triaxial acceleration sensor 23, the torque of the cutting tooth is recorded by the torque sensor 22, and the single-tooth rock cutting condition is dynamically recorded by the high-speed camera 19, which is more conducive to analyzing the failure mechanism of the PDC cutting tooth 13 under high-frequency torsional vibration. At the same time, it can also be used for rock drillability tests and abrasiveness tests, and can also explore the failure mechanism of the drill bit under high-frequency torsional vibration, with rich and diverse equipment functions.
[0030] The present invention conducts cutting experiments on the same batch of rock samples 18 under different vibration frequencies, different amplitudes, and different test durations to determine the coefficients. Subsequently, experiments can be carried out on rock samples 18 with different lithologies to further improve the high-frequency torsional vibration failure life model of the PDC cutting tooth 13. In addition, the test device can be used to verify the high-frequency torsional vibration failure life model of the PDC cutting tooth 13.
[0031] The present invention can achieve the drilling of the rock sample 18 by the PDC cutting tooth 13 under the influence of high-frequency torsional vibration. The high-frequency torsional vibration excitation system simulates the working condition of high-frequency torsional vibration occurring during the actual oil drill bit drilling, and can generate high-frequency torsional vibration with approximate vibration frequency and amplitude. By controlling the loading system and the rotation control system, the PDC cutting tooth 13 cutting rock experiments with different weights on bit (WOB) and different rotary speeds can be realized, and multiple parameters of the entire cutting process can be monitored in real time. The vibration condition of the PDC cutting tooth 13 is recorded by the triaxial acceleration sensor 23, the torque of the PDC cutting tooth 13 and the torque output by the high-frequency torsional vibration excitation system are recorded by the torque sensor 22, and the PDC cutting tooth 13 cutting rock condition is dynamically recorded by the high-speed camera 19.
[0032] The above are only the preferred and feasible embodiments of the present invention, and do not limit the scope of the rights of the present invention accordingly. All equivalent changes made by using the content of the specification and drawings of the present invention are included in the scope of the rights of the present invention.
Claims
1. An experimental device for evaluating the failure damage of a single PDC tooth under high-frequency torsional vibration, characterized in that: It includes a device bearing system, a loading system, a rotation control system, a high-frequency torsional vibration excitation system and a real-time monitoring system; the device bearing system includes a base which is set on the horizontal ground. Four support frames are arranged on the upper surface of the base. The four support frames are spaced from each other and symmetrically arranged in pairs. A loading frame parallel to the base is jointly arranged at the upper ends of the four support frames; the loading system is arranged on the loading frame and includes a control panel arranged on the loading frame. A hydraulic cavity is arranged in the center of the loading frame. A loading pump is connected to the hydraulic cavity. A liquid injected into the hydraulic cavity is arranged in the loading pump. A piston reciprocating in the height direction is arranged in the hydraulic cavity. A loading rod extending downward out of the hydraulic cavity is vertically fixed to the lower bottom surface of the piston; the rotation control system is connected to the loading rod and includes a system housing connected to the loading rod. A rotation motor is arranged on the system housing. The output end of the rotation motor extends into the system housing. A rotation shaft is arranged on the lower bottom surface of the system housing. The upper end of the rotation shaft vertically penetrates the lower bottom surface of the system housing and is in transmission connection with the output end of the rotation motor. A rotation disk is connected to the lower end of the rotation shaft. A single-tooth clamp is arranged on the lower bottom surface of the rotation disk. A PDC cutting tooth is installed on the single-tooth clamp; the high-frequency torsional vibration excitation system is arranged on the upper surface of the base and includes a rock sample turntable arranged at the center of the upper surface of the base. A rock sample corresponding to the PDC cutting tooth is placed on the rock sample turntable. A servo motor is arranged on the front side surface of the base. A driver connected to the servo motor is arranged outside the base. A control system is jointly connected to the servo motor and the driver; the real-time monitoring system is connected to the bearing system and the rotation control system.
2. The test device for evaluating the failure damage of PDC single-tooth high-frequency torsional vibration according to claim 1, wherein: The real-time monitoring system includes a high-speed camera for recording the real-time state of the cutting tooth cutting the rock sample. The high-speed camera is arranged on any support frame and corresponds to the rock sample and the cutting tooth; a torque sensor arranged on the upper surface of the rotation disk and a torque sensor arranged on the rock sample turntable; a triaxial acceleration sensor arranged in the single-tooth clamp and a load sensor arranged in the single-tooth clamp.
3. The test device for evaluating the failure damage of PDC single-tooth high-frequency torsional vibration according to claim 2, wherein: The control system includes control logic programming, PID parameter tuning, resonance suppression and FEM software; and the control logic programming, PID parameter tuning and resonance suppression cooperate together to enable the high-frequency torsional vibration excitation system to generate a vibration frequency.
4. The test device for evaluating the failure damage of PDC single-tooth high-frequency torsional vibration according to claim 3, wherein: The rock sample turntable includes a turntable fixed at the center of the upper surface of the base. The turntable is connected to the servo motor. A square rotating shaft is fixed at the center of the upper surface of the turntable. A square hole is arranged at the bottom of the rock sample. The square hole is adapted to the square rotating shaft and the rock sample is installed on the square rotating shaft through the square hole.
5. The test device for evaluating the failure damage of PDC single-tooth high-frequency torsional vibration according to claim 4, characterized in that: The control panel is connected to the loading pump and the rotation motor.
6. The test device for evaluating the failure damage of PDC single-tooth high-frequency torsional vibration according to claim 5, characterized in that: A counterweight adapted to the PDC cutting teeth and the single-tooth fixture is also fixedly connected to the lower bottom surface of the rotating disk; the single-tooth fixture includes two vertical connecting plates vertically fixed to the lower bottom surface of the rotating disk. The two vertical connecting plates are spaced apart from each other and parallel to each other. Through holes facing each other are provided at the lower ends of the two vertical connecting plates. A connecting rod is commonly installed on the through holes. The PDC cutting teeth are installed on the connecting rod and located between the two vertical connecting plates. Tightening nuts threadedly connected to the connecting rod are provided on the outer sides of the two vertical connecting plates. An adjusting nut is clamped between the PDC cutting teeth and one of the vertical connecting plates.
7. A method for using the test device for evaluating the failure damage of PDC single-tooth high-frequency torsional vibration according to claim 6, characterized in that: A single-tooth cutting test method including high-frequency torsional vibration and a method for quantitatively evaluating PDC single-tooth damage.
8. The method for using the test device for evaluating the failure damage of PDC single-tooth high-frequency torsional vibration according to claim 7, characterized in that: The single-tooth cutting test method including high-frequency torsional vibration comprises the following steps: S1. Design an experimental scheme. Build a model and simulate the bottom hole assembly through FEM software. Obtain the vibration frequency and amplitude through modal analysis and harmonic response analysis, and determine the drilling parameters required for the test. S2. Fix the PDC cutting teeth in the single-tooth fixture. Then, adjust the back rake angle by adjusting the single-tooth fixture. After adjustment, fix it with nuts. After processing the rock sample, place it in the turntable. S3. Subsequently, operate the control panel to start loading. Start the high-speed camera. Adjust the position of the high-speed camera so that the cutting area of the rock sample appears within the field of view of the high-speed camera. Check whether the rest of the components react normally. S4. Then, start the high-frequency torsional vibration excitation system, input the vibration frequency and amplitude, so that the rock sample generates corresponding high-frequency torsional vibration. Start the rotation control system to make the PDC cutting teeth start to rotate around the rotation axis. After the rotation speed of the rotation control system is constant, start the loading system, apply a load to the PDC cutting teeth through the loading frame, and make the PDC cutting teeth cut along the rock sample. Its cutting path realizes the cutting of the rock sample by the cutting teeth under high-frequency torsional vibration. S5. After the cutting process is completed, stop the axial loading of the loading frame, raise the rotation control system, stop the rotation control system and the high-frequency torsional vibration excitation system, turn off the testing machine, and record and save the measurement data.
9. The method of using the test device for evaluating the failure damage of PDC single tooth high-frequency torsional vibration according to claim 7, characterized in that: The method for quantitatively evaluating PDC single-tooth damage includes a failure life model of PDC cutting teeth under high-frequency torsional vibration; the method for quantitatively evaluating PDC single-tooth damage based on the failure life model of PDC cutting teeth under high-frequency torsional vibration comprises the following steps: S1. Under high-frequency torsional vibration of PDC cutting teeth, the damage amount of PDC cutting teeth is related to the applied drilling pressure, rotational speed, vibration frequency and amplitude. Utilize the failure life model of PDC cutting teeth under high-frequency torsional vibration and predict the damage amount of the cutting teeth according to the existing test conditions. S2. Wipe the tested PDC cutting teeth clean, and then take pictures of the PDC cutting teeth through a high-definition camera to analyze the failure type of the PDC cutting teeth. S3. Then, use image data processing software to evaluate and grade the failure damage amount of PDC cutters, conduct a quantitative analysis of the damage amount of PDC cutters, obtain the actual damage amount of PDC cutters under high-frequency torsional vibration, compare it with the predicted damage amount of PDC cutters, and further predict the failure life of PDC cutters under high-frequency torsional vibration.
10. The method for using the test device for evaluating the failure damage of PDC single-tooth high-frequency torsional vibration according to claim 9, characterized in that: The high-frequency torsional vibration failure life model of the PDC cutting tooth includes ; through the high-frequency torsional vibration failure life model of the PDC cutting tooth, it is determined that within a specified time, under high-frequency torsional vibration of the PDC cutting tooth, the damage amount of the PDC cutting tooth is related to the applied drilling pressure, rotational speed, vibration frequency, and amplitude; among them, is the damage amount of the PDC cutting tooth; is the drilling pressure, with the unit of kN; is the rotational speed, with the unit of r / min; is the vibration frequency, with the unit of Hz; is the amplitude, with the unit of m / s²; I1 - I4 are all dimensionless coefficients.