Shale formation horizontal well drill string system dynamics simulation experiment device and experiment method

Abstract

The invention discloses a shale formation horizontal well drill string system dynamics simulation experiment device and method, and the device comprises a data collection system, a control system, and a power system, a drill string system, a rock breaking system and a drilling fluid circulation system which are connected in sequence. The data acquisition system is used for acquiring drilling pressure, rotating speed, torque, drilling footage, mechanical drilling speed and vibration acceleration of a well bottom and the ground in a rock breaking experiment in real time; and the control system is used for regulating and controlling the drilling parameters and the drilling fluid circulating pressure in the experiment process on line. The device can simulate the motion state of the drill bit and the drill string horizontally drilling into the shale stratum, accurately measure the vibration characteristics of the coupling system in real time, and provide experimental data support for subsequent research on the dynamics of the shale layer horizontal well drill bit-drill string coupling system.

Description

Technical Field

[0001] This invention belongs to the field of drilling technology and relates to a dynamic simulation experimental device and method for a horizontal well drill string system in shale formations. Background Technology

[0002] The number of unconventional oil and gas horizontal wells is rapidly increasing, and horizontal well drilling technology has become a major means of increasing oil and gas well production and enhancing recovery rates. During horizontal well drilling, the motion of the drill bit and drill string is highly complex. Field testing and research on drill bit-drill string coupled vibration is costly, cannot accurately decouple various factors, and yields limited data for system analysis. Developing an experimental device that can simulate normal horizontal drilling and measure various physical quantities during the drilling process will be beneficial for studying the motion state and vibration characteristics of the drill bit and drill string.

[0003] In my country, shale gas deposits are generally buried at depths exceeding 3,000 meters, resulting in denser shale formations. With increasing depth, the fracturing pressure and in-situ stress of deep shale increase. Simultaneously, the rock's mechanical brittleness decreases with rising formation temperature, while its plasticity increases. Fracturing pressures are generally above 90 MPa and are significantly affected by natural fractures, making the operation significantly more difficult than in medium-deep formations. During drilling, the extremely poor drillability of high-strength and highly abrasive shale, high formation temperatures, and well-developed faults in the target layer lead to low rates of drilling, long drilling cycles, wellbore collapse, a high rate of accidents, and persistently high drilling costs.

[0004] For deep shale drilling, the anisotropic fracturing mechanism is not fully understood, and the basis for drill bit design and selection is insufficient, making it impossible to achieve "one-trip" well completion for long horizontal sections. Furthermore, in horizontal well drilling, it is difficult to accurately measure the impact of dynamic vibrations in the drill bit-drill string coupling system on parameters such as drilling pressure, rotational speed, torque, mechanical drilling speed, and rock damage. Therefore, there is an urgent need for more comprehensive experimental techniques to simulate the dynamic characteristics of the drill bit-drill string coupling system, and for experimental devices and methods that can accurately measure and monitor various drilling physical quantities under the coupling system. Summary of the Invention

[0005] In order to effectively solve the problems existing in the prior art, the purpose of this invention is to provide a dynamic simulation experimental device and experimental method for horizontal well drilling string systems in shale formations.

[0006] To achieve the above objectives, the present invention employs the following technical solutions:

[0007] The dynamic simulation experimental device for horizontal well drilling string system in shale formations includes a data acquisition system, a control system, and a power system, a drill string system, a rock breaking system, and a drilling fluid circulation system connected in sequence. The data acquisition system is used to collect data on drilling pressure, rotational speed, torque, footage, mechanical drilling speed, and vibration acceleration at the bottom of the well and the surface during the rock breaking experiment in real time. The control system is used to adjust the drilling parameters and drilling fluid circulation pressure online during the experiment.

[0008] As a preferred embodiment, the drill string system includes a simulated wellbore, a drill pipe installed inside the wellbore, and a fiber Bragg grating sensor. A force measuring section is provided on the drill pipe, and a fiber Bragg grating sensor is provided on the outer surface of the force measuring section.

[0009] Further preferably, the force measuring section is provided with multiple components, and the fiber optic grating sensors are disposed on the outer surface of the central axis of the force measuring section, and multiple components are arranged symmetrically along the axial direction.

[0010] As a preferred embodiment, the power system includes a rotary power module and an axial power module. The rotary power module includes a rotary motor, a reducer, and a frequency converter to provide driving torque for the drill string system. The axial power module is a hydraulic servo system that provides axial power to the drill string system.

[0011] Further preferably, the axial power module includes a hydraulic cylinder, a hydraulic lock, a solenoid directional valve, a metering pump, an oil filter, and an oil tank connected in sequence.

[0012] As a preferred embodiment, the rock breaking system includes a simulated micro drill bit, a rock clamping device, and an acoustic emission system. The acoustic emission system includes an acoustic emission sensor, an amplifier, an acoustic emission acquisition card, and an acquisition computer host. The acoustic emission sensor is fixed on the rock sample.

[0013] Further preferably, the simulated micro drill bit is a micro PDC drill bit with a drill bit radius R of 35 mm, a PDC composite sheet diameter of 8.2 mm, 3 blades and 3 water inlets, an included angle of 120 degrees between the blades, and water inlets between adjacent blades.

[0014] In a further preferred embodiment, the acoustic emission signal collected by the acoustic emission sensor is amplified by an amplifier and connected to an acoustic emission acquisition card to receive the acoustic emission signal. The acoustic emission signal is then analyzed, processed, and stored by a computer host.

[0015] In a further preferred embodiment, the acoustic emission sensor comprises six sensors, arranged in a triangular array of three sensors on the fracture surface and top of the rock sample, to determine the location of the sound source generated by rock damage and fracture during the rock breaking test.

[0016] In another preferred embodiment, the acoustic emission sensor is wrapped with tape around the rock sample, and coupling agent is applied between the rock sample and the acoustic emission sensor to fill the gap.

[0017] In a further preferred embodiment, the drilling fluid circulation system includes a mud pump, a rotary sealing joint, a pressure sensor, a drilling fluid circulation tank, a filtration mechanism, and an inlet pipe. The pressure sensor is located below the rotary sealing joint. The drilling fluid is contained in the drilling fluid circulation tank. After passing through the filtration mechanism, the drilling fluid is pumped to the inlet pipe by the mud pump and then enters the drill pipe through the rotary sealing joint.

[0018] As a preferred embodiment, the data acquisition system includes an encoder, an accelerometer, a data acquisition card, and a fiber Bragg grating sensor demodulator. The encoder is used to detect the rotational speed and displacement at both ends of the drill string. The data acquisition card is used to transmit and receive encoder signals and receive vibration accelerometer data (three-axis acceleration) to measure the vibration of the drill bit and drill string system.

[0019] As a preferred embodiment, the control system includes a programmable logic controller, a rotary motor frequency converter, and a mud pump controller.

[0020] Further preferably, the programmable logic controller is connected to a PLC expansion module for outputting analog signals to the rotary motor frequency converter and the mud pump controller.

[0021] This invention also describes an experimental method for a dynamic simulation experimental device for a horizontal well drill string system in shale formations, comprising the following steps:

[0022] S1, install the rock sample block onto the rock clamping device, fix the acoustic emission sensor in a triangular array on the rock sample block, and turn on the acoustic emission system;

[0023] S2, power on and start the drilling fluid circulation system, power system, data acquisition system and control system, and check each system to ensure that they are in the initial state.

[0024] S3, the drilling fluid circulation pressure of the experimental device is first set by the control system. When the drilling fluid circulation pressure stabilizes at the target value, the rotation speed and drilling pressure target values ​​are set, and the drill string system spindle rotates and feeds axially.

[0025] S4, Start data acquisition on the computer host, initialize each information acquisition card, and collect physical quantity test data;

[0026] S5. After the simulated micro-drill bit has stabilized and broken the rock for 1-2 minutes, turn off the data acquisition system and open the electromagnetic reversing valve to retract the power system.

[0027] S6. Based on the experimental requirements, load the next set of test points, repeat steps S1 to S5 until all tests are completed, and then shut down the entire system.

[0028] This invention utilizes fiber optic grating sensors instead of traditional strain gauges to measure drill bit pressure and torque during drilling, effectively overcoming electromagnetic interference in the environment. It employs acoustic emission technology to analyze and study the damage state of internal fractures in rock materials during rock-breaking tests. A three-bladed PDC micro-drill bit, designed with realistic tooth arrangement of actual drill bits, is used to break rocks, better characterizing the drill bit's performance in shale formations and under operating conditions. Data acquisition cards and various sensors are used to collect real-time physical quantities such as drill pressure, rotational speed, torque, footage, and mechanical drilling speed at the bottom and surface during rock-breaking tests, providing data support for the study of the dynamics of horizontal well drilling string systems in shale formations. The control system employs an advanced programmable logic controller and its expansion modules, providing high flexibility for the automated control of drilling parameters during experiments. This invention incorporates a drilling fluid circulation device, considers drill string flexibility, and accurately reflects rock / drill bit interactions, providing an advanced practical understanding of the impact of drill string dynamics on drill bit life and performance. It also offers a more comprehensive and scientific experimental setup and method for optimizing the design of PDC drill bits and drilling parameters in horizontal well drilling in shale formations.

[0029] The present invention has the following advantages:

[0030] This invention can simulate the motion state of the drill bit and drill string when drilling horizontally into shale formations, and accurately measure the vibration characteristics of the coupled system in real time, providing experimental data support for subsequent research on the dynamics of the drill bit-drill string coupled system in horizontal wells of shale formations.

[0031] Figure descriptions (Figure labels 12, 13, and 35 do not have corresponding text descriptions).

[0032] Figure 1 This is a schematic diagram of the experimental apparatus of the present invention;

[0033] Figure 2 This is a schematic diagram of the hydraulic servo system of the axial power module of the present invention;

[0034] Figure 3 This is a schematic diagram of the fiber optic grating sensor arrangement of the present invention;

[0035] Figure 4 This is a schematic diagram of the acoustic emission system of the present invention;

[0036] Figure 5 This is a schematic diagram of the drilling fluid circulation device of the present invention;

[0037] Figure 6 This is a schematic diagram of the data acquisition system structure of the present invention;

[0038] Figure 7 This is a schematic diagram of the control system structure of the present invention. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings.

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0041] Example:

[0042] like Figure 1-7 As shown, a dynamic simulation experimental device for a horizontal well drill string system in shale formation is arranged on an experimental platform 1. The device includes a power system 2, a drill string system 3, a rock breaking system 4, a drilling fluid circulation system 5, a data acquisition system 6, and a control system 7. The experimental platform 1 is equipped with a support and fixing frame 11, a motor fixing frame 12, and a drill string fixing sleeve 13, which are used to assist in fixing the hydraulic cylinder 210 of the power system, the rotary motor, and the entire drill string system. The power system 2 provides rotational torque and axial power for the experimental setup; the drill string system 3 simulates the motion of the drill pipe within the wellbore, using fiber optic gratings to measure drilling pressure and torque to effectively overcome electromagnetic interference in the environment; the rock breaking system 4 employs a micro-drill bit with actual drill bit tooth layout to realistically reflect the drill bit-rock interaction, and utilizes an acoustic emission system to study the damage state of internal rock material fracture during the rock breaking test; the drilling fluid circulation system 5 assists the drill bit in rock breaking, accelerating the mechanical drilling speed and reducing the drill bit temperature; the data acquisition system 6 collects physical quantities such as drilling pressure, torque, rotational speed, displacement, and acceleration from the surface and bottom of the well, providing data support for the study of the dynamics of the drill string system in shale formation horizontal wells; the control system 7 uses an advanced programmable logic controller and its expansion modules to online control drilling parameters and drilling fluid circulation pressure during the experiment, improving experimental reliability and safety.

[0043] The power system 2 includes an axial power module 21 and a rotary power module 22. The axial power module 21 consists of a hydraulic servo system, including a hydraulic cylinder 210, a hydraulic lock 211, a 6-port solenoid directional valve 212, a pressure sensor 213, a proportional relief valve 214, a carbon steel oil tank 215, a pressure gauge 216, a quantitative oil pump 217, a level gauge 218, and an oil filter 219. The valve core of the proportional relief valve 214 is controlled by a proportional electromagnet, making the pressure proportional to the input electrical signal. This allows for continuous and proportional control of the oil pressure, providing axial power to the system to achieve constant drilling pressure feed control on the horizontal platform. The rotary power module 22 consists of a rotary motor, a reducer, and a frequency converter, providing drive torque to the drill string system. A high-performance vector frequency converter is preferred to achieve high control accuracy and meet experimental requirements.

[0044] Specifically, the axial power module 21 inputs a given load value through a computer monitoring interface. This value, after being input into the programmable logic controller 71, serves as the load limit reference value and is compared in real time with the actual system load. The loading process begins with a low current, and the proportional relief valve 214 gradually loads the system, causing the tension and compression forces to rise gradually. During tension and compression, the load value is detected and fed back to the input of the control loop. Based on the control algorithm, a classic PID control algorithm can be used. The control parameters need to be adjusted experimentally to determine the control output value. When the actual load value reaches the given value, the process switches to a load holding process, and then switches to an unloading process according to the set holding time, thus completing one loading control process.

[0045] The drill string system 3 includes a simulated wellbore 31 and a drill pipe 32 installed inside the wellbore, force-measuring sub-sections 33 (34) set at both ends of the drill pipe, a data transmission fiber optic cable 35, and a fiber optic grating sensor 36 (37). The simulated wellbore 31 is preferably made of plexiglass tubing to facilitate observation of the movement and deformation of the drill pipe within the simulated wellbore. The drill pipe 32 is at least 4m long to better reproduce the drilling conditions. The force-measuring sub-sections 33 (34) are externally threaded at both ends and connected to the drill string, rotary motor shaft, and drill pipe 32 via the threads. It is understood that the force-measuring sub-sections 33 (34) can be arranged at multiple locations on the drill pipe 32 to measure the stress at multiple points on the drill pipe 32. In this embodiment, the fiber optic grating sensor 36 (37) is set on the outer surface of the central axis of the force-measuring sub-section 33 (34). At least two fiber optic gratings are arranged symmetrically along the axial direction to measure the axial stress, and two fiber optic gratings are arranged at 45° along the axis to measure torque, in order to better eliminate the influence error of temperature.

[0046] The rock-breaking system 4 includes a simulated micro drill bit 41, a rock clamping device 42, and an acoustic emission system 43. The simulated micro drill bit 41 is a micro PDC drill bit. The rock clamping device 42 includes a rock fixing frame and a rock sample block mounted on the fixing frame. The acoustic emission system includes an acoustic emission sensor 431, a signal amplifier 432, an acoustic emission acquisition card 433, and a data acquisition computer host 68. The acoustic emission sensor 431 is fixed on the rock sample block. The acoustic emission signal is amplified by the amplifier 432 and connected to the acoustic emission acquisition card 433 to receive the acoustic emission signal. The data acquisition computer host 68 analyzes, processes, and stores the acoustic emission signal to study the damage state of internal fracture of the rock material during the rock-breaking test.

[0047] The simulated micro drill bit 41 has a radius R of 35mm and a PDC composite plate diameter of 8.2mm. It has a total of 3 blades and 3 water inlets, with an included angle of 120 degrees between the blades and water inlets between adjacent blades. To reduce the impact of drill bit vortex on the overall force balance, the tooth layout design adopts the lateral force balance theory. The PDC teeth are welded to the blades to meet the working strength requirements during rock breaking. The drill bit blades adopt a straight-line design, with the blades and the base machined separately. Bolt holes are machined on the side of the blades, and they are connected to the base with bolts to assemble a drill bit with detachable, complete blades.

[0048] The rock mounting bracket includes a base, three lateral steel plates, and bolts for fixing the rock to the steel plates. The steel plates and base are reinforced with ribs. The rock block size can be selected from 100mm*100mm*100mm to 200mm*200mm*200mm. In this embodiment, six acoustic emission sensors are mounted on the rock block, arranged in a triangular array of three sensors on the fracture surface and top of the rock block to determine the location of the sound source generated by rock damage and fracture during the rock breaking test. The sensors are wrapped with tape to the rock. To prevent signal attenuation due to vacuum, coupling agent is further applied between the rock sample and the acoustic emission sensors to fill the gap.

[0049] The drilling fluid circulation system 5 includes a rotary sealing joint 51, a drilling fluid pressure sensor 52, a drilling fluid circulation tank 53, a filtration mechanism 54, a mud pump 55, and an inlet pipe 56. The drilling fluid placed in the drilling fluid circulation tank 53 is filtered by the filtration mechanism 54 and pumped by the mud pump 55 to the inlet pipe 56. It then enters the drill pipe through the rotary sealing joint 51. Four water inlets inclined at 45° to the drill bit are provided at the corresponding positions on the drill pipe to guide the drilling fluid. A drilling fluid pressure sensor 53 is installed below the rotary sealing joint 52 to facilitate real-time detection of the circulating pressure of the drilling fluid. The drilling fluid then enters the simulated micro-drill bit 41 through the drill pipe. The drilling fluid is sprayed through the water inlet of the micro-drill bit to the rock breaking point of the drill bit, which accelerates the mechanical drilling speed of rock breaking and reduces the temperature of the drill bit, thus assisting in rock breaking.

[0050] The data acquisition system 6 includes a rotational speed 62 (63) and a displacement encoder 64 (65) for detecting the rotational speed at both ends of the drill string, an accelerometer 66 (67), a data acquisition card 61, a fiber optic grating sensor demodulator 69, an acoustic emission acquisition card 433, and a data acquisition computer host 68. The control system 7 includes a programmable logic controller 71, a PLC expansion module 72, a rotary motor frequency converter, a proportional relief valve 214 for the hydraulic servo system, and a mud pump controller for the drilling fluid circulation system.

[0051] Specifically, the data acquisition system 6 transmits and receives encoder signals and acceleration data through the data acquisition card 61, receives fiber optic grating sensor signals through the fiber optic grating sensor demodulator 69, and receives acoustic emission signals through the acoustic emission acquisition card 433. All data is visualized, analyzed, and stored on the acquisition computer host 68 to save resources and reduce the complexity of manual operation of the data acquisition system.

[0052] The control system 7 outputs analog signals to the rotary power module 22, axial power module 21, and mud pump controller of the drilling fluid circulation system of the power system 2 via the PLC expansion module 72 of the programmable logic controller 71, in order to complete the real-time control of parameters such as rotational speed, drilling pressure, and drilling fluid circulation pressure during the rock breaking experiment. Furthermore, a communication isolation module is connected between the PLC and each controller to solve the problem of data communication interference in complex electromagnetic environments.

[0053] The device of this invention is installed on an experimental bench for testing. It also provides a dynamic simulation experimental method for a horizontal well drill string system in shale formations. In this example, the rock sample dimensions (length*width*height) are selected as 150mm*150mm*150mm.

[0054] The first step is to attach the target rock sample to the rock clamping device, fix the acoustic emission probes in a triangular array on the rock block, turn on the acoustic emission system, and set the frequency of the preamplifier to 1000KHz.

[0055] The second step is to power on and start the drilling fluid circulation system, power system, and data acquisition and control system, and check each system to ensure that they are in their initial state.

[0056] The third step involves setting the drilling fluid circulation pressure for horizontal drilling using the control system. Once the drilling fluid circulation pressure stabilizes at the target value and is recorded, the target values ​​for rotation speed and drilling pressure are set, and the device is started. The spindle rotates and feeds axially. In this example, the drilling fluid circulation pressure is 0.3 MPa, the rotation speed is 60 r / min, and the drilling pressure is 2500 N.

[0057] The fourth step is to start the data acquisition system, enable data acquisition on the computer terminal, initialize each information acquisition card, collect various physical quantities, observe the experimental phenomena, and focus on observing and recording the test data of physical quantities such as drilling pressure, torque, displacement, rotation speed, vibration acceleration, and mechanical drilling speed during the process of the micro drill bit breaking rocks.

[0058] Fifth, after the micro-drill bit has stabilized after breaking the rock, and the test is completed within 1-2 minutes, shut down the data acquisition system and open the electromagnetic reversing valve to retract the axial power system.

[0059] Step 6: According to the experimental requirements, load the next set of test points and repeat steps 1 to 5 until the test is completed under all different combinations of drilling fluid circulation pressure, rotation speed and drilling pressure, etc., and then shut down the entire system.

[0060] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A shale formation horizontal well drill string system dynamics simulation experimental device, characterized in that: The drilling system comprises a data acquisition system, a control system, and sequentially connected power system, drill string system, rock breaking system, and drilling fluid circulation system.

2. The shale formation horizontal well drill string system dynamics simulation experimental apparatus according to claim 1, characterized in that: The drill string system comprises an analog wellbore, drill pipe installed in the wellbore, and fiber bragg grating sensors, and the drill pipe is provided with force measuring sub, and the outer surface of the force measuring sub is provided with fiber bragg grating sensors.

3. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 2, wherein: The force measuring sub is provided with a plurality of fiber bragg grating sensors arranged on the outer surface of the central axis of the force measuring sub in an axial symmetry.

4. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 1, wherein: The power system comprises a rotary power module and an axial power module, the rotary power module comprises a rotary motor, a speed reducer and a frequency converter, and provides driving torque for the drill string system; the axial power module is a hydraulic servo system, and provides axial power for the drill string system.

5. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 4, wherein: The axial power module comprises sequentially connected hydraulic cylinder, hydraulic lock, electromagnetic reversing valve, quantitative oil pump, oil filter and oil tank.

6. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 1, wherein: The rock breaking system comprises an analog micro drill bit, a rock clamping device and an acoustic emission system, the acoustic emission system comprises acoustic emission sensors, amplifiers, acoustic emission acquisition cards and a computer host, and the acoustic emission sensors are fixed on the rock sample.

7. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 6, wherein: The analog micro drill bit is a micro PDC drill bit, the drill bit radius R is 35 mm, the PDC composite sheet diameter is 8.2 mm, there are three blades and three water eyes, the included angle between the blades is 120 degrees, and the water eyes are arranged between adjacent blades.

8. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 6, wherein: The acoustic emission signals collected by the acoustic emission sensors are amplified by the amplifiers, connected to the acoustic emission acquisition cards to receive the acoustic emission signals, and analyzed, processed and stored by the computer host.

9. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 6, wherein: The acoustic emission sensors are arranged in an array on the broken surface of the rock sample in a triangular shape by three sensors each, and are used to determine the acoustic source position generated by rock damage and fracture in the rock breaking test.

10. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 9, wherein: The acoustic emission sensors are wrapped on the rock sample by adhesive tape, and coupling agent is applied between the rock sample and the acoustic emission sensors to fill the gap.

11. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 2, wherein: The drilling fluid circulation system comprises a mud pump, a rotary sealing joint, a pressure sensor, a drilling fluid circulation tank, a filtering mechanism and a liquid inlet pipe, the pressure sensor is arranged below the rotary sealing joint, the drilling fluid circulation tank is provided with drilling fluid, the drilling fluid is pumped to the liquid inlet pipe by the mud pump after passing through the filtering mechanism, and enters the inside of the drill pipe through the rotary sealing joint.

12. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 1, wherein: The data acquisition system comprises an encoder, an acceleration sensor, a data acquisition card and a fiber bragg grating sensor demodulator, the encoder is used to detect the rotation speed and displacement of both ends of the drill string, and the data acquisition card is used to transmit and receive the encoder signal and receive the acceleration sensor data.

13. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 1, wherein: The control system comprises a programmable logic controller, a rotary motor frequency converter and a mud pump controller.

14. The shale formation horizontal well drill string system dynamics simulation experimental apparatus of claim 13, wherein: The programmable logic controller is connected with a PLC expansion module, and is used to output analog quantity to the rotary motor frequency converter and the mud pump controller.

15. An experimental method of the shale formation horizontal well drill string system dynamics simulation experimental device according to any one of claims 1-14, characterized in that, The method comprises the following steps: S1, install the rock sample on the rock clamping device, fix the acoustic emission sensor in a triangular array on the rock sample, and turn on the acoustic emission system; S2, turn on the drilling fluid circulation system, power system, data acquisition system and control system, and check all systems to ensure that they are in the initial state. S3, set the drilling fluid circulation pressure of the experimental device for horizontal drilling through the control system, and then set the target values of the rotation speed and drilling pressure when the drilling fluid circulation pressure is stable at the target value. The drill string system main shaft rotates and feeds axially; S4, open the data acquisition system on the host computer to collect data, initialize all information acquisition cards, and collect physical quantity test data; S5, after the simulated micro drill bit breaks the rock stably for 1-2 minutes, turn off the data acquisition system and open the electromagnetic directional valve to make the power system retreat. S6, according to the experimental requirements, load the next test point, repeat steps S1 to S5 until all tests are completed, and turn off all systems.

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