A downhole complex condition simulation device and method

Abstract

The application discloses a kind of downhole complex condition simulation device and method, device includes simulation wellbore, drilling fluid injection mechanism, drilling fluid discharge mechanism, formation fluid injection mechanism and formation fluid discharge mechanism, the simulation wellbore includes mounting plate, first fixed seat, second fixed seat, outer sleeve, inner drill rod, extrusion mechanism and rotating mechanism;The drilling fluid injection mechanism is used to inject mud into one end of the outer sleeve.The beneficial effects of the present application are: at least one by formation fluid injection mechanism into the side inlet injection gas or liquid, thereby simulating the gas invasion or well kick when actual drilling, by formation fluid discharge mechanism simulates the loss of circulation when actual drilling, by the device, the actual downhole complex conditions can be simulated in the laboratory, necessary conditions can be created for the indoor study of the process of cuttings transport, well leakage, overflow, simultaneous occurrence of well leakage and overflow, three-phase flow process, and can be used to guide the establishment of flow model and drilling operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drilling engineering, in particular to a downhole complex working condition simulation device and method. BACKGROUND

[0002] Flow circulation refers to the complete flow process of drilling fluid (mud) pumped from the wellhead by a drilling pump through the drilling pipe string, drill bit and annulus back to the ground mud pit, and is the basis for drilling implementation. However, due to the complexity of downhole conditions and the concealment of downhole risks, many complex working conditions may occur during the flow circulation in the drilling process, including: (1) high temperature and high pressure are common complex downhole working conditions in the drilling exploration field which gradually moves towards deep layers and deep water, and the circulating fluid is mostly non-Newtonian fluid, whose rheological properties change obviously with temperature and pressure, and the flow law of the fluid under different temperature and pressure conditions will change; (2) during the drilling process, rock debris generated by rock breaking needs to be carried out of the well by fluid circulation, and the debris will exist in the wellbore in a suspended state or a debris bed state during the circulation and carrying process, wherein the suspended debris will change the density of the fluid, and the debris bed will change the size of the wellbore flow passage and further change the flow state in the wellbore; (3) during the actual circulation process, overflow, loss circulation or overflow and loss may occur at the same time, and sudden fluid invasion, outflow or exchange will change the fluid flow state in the wellbore; at the same time, due to the incomplete matching of the invading fluid and the original circulating fluid in the wellbore, the physical properties of the original circulating fluid will change; (4) during the drilling process, due to different construction conditions and drilling rig states when drilling different formations, the stress on the drill pipe may change, which may cause the drill pipe to bend, and the change in the shape of the drill pipe will also affect the flow state of the drilling fluid in the annulus.

[0003] Since the downhole is a blind area that cannot be seen, it is difficult to monitor the flow state in the wellbore and analyze the flow law by relying only on the sensors arranged at the wellhead and the well bottom, and it is even more difficult to scientifically handle the flow anomalies in the wellbore, which may lead to serious downhole accidents and increase the construction cost and operation risk. Therefore, it is necessary to study the flow change law caused by various complex working conditions in the downhole circulation process, establish a visual multifunctional test bench, and scientifically guide the establishment of the flow model and drilling construction. At present, there is no such multifunctional simulation method and device. SUMMARY

[0004] The present application aims to overcome the above technical deficiencies and provide a downhole complex working condition simulation device and method to study the flow change law caused by various complex working conditions in the downhole circulation process.

[0005] To achieve the above technical purpose, the present application adopts the following technical solution:

[0006] This invention provides a device for simulating complex downhole working conditions, comprising:

[0007] A simulated wellbore includes a mounting plate, a first fixed seat, a second fixed seat, an outer sleeve, an inner drill rod, a pressing mechanism, and a rotating mechanism. The first fixed seat and the second fixed seat are respectively fixed to both ends of the mounting plate. The outer sleeve is fixed to the mounting plate. The outer sleeve has several openable and closable side inlets and several openable and closable side outlets along its length. Each side inlet is equipped with a first temperature sensor and a first pressure sensor. Each side outlet is equipped with a second temperature sensor and a second pressure sensor. The outer sleeve is made of transparent material, and several high-speed cameras are arranged on the outside of the outer sleeve. The inner drill rod is built into the outer sleeve. The fixed end of the rotating mechanism is fixed to the first fixed seat. The rotating end of the rotating mechanism is connected to the fixed end of the pressing mechanism. The telescopic end of the pressing mechanism is fixedly connected to one end of the inner drill rod. The other end of the inner drill rod is rotatably connected to the second fixed seat.

[0008] A drilling fluid injection mechanism for injecting drilling mud into one end of the outer casing;

[0009] A drilling fluid discharge mechanism, wherein the drilling fluid discharge mechanism is connected to the other end of the outer casing and is used to discharge drilling fluid;

[0010] A formation fluid injection mechanism, which is connected to each of the side inlets and is used to inject gas or liquid into at least one of the side inlets; and a formation fluid discharge mechanism, which is connected to each of the side outlets and is used to discharge gas or liquid discharged from at least one of the side outlets.

[0011] In some embodiments, the extrusion mechanism includes an extrusion cylinder and a pressure sensor, and the rotation mechanism includes a rotary motor, the housing of which is fixed to the first fixed base;

[0012] The extrusion mechanism includes an extrusion cylinder and a pressure sensor. The output shaft of the rotary motor is fixedly connected to the cylinder body of the extrusion cylinder. The output shaft of the extrusion cylinder is fixedly connected to one end of a tension sensor. The other end of the tension sensor is fixedly connected to one end of a torque sensor. The other end of the torque sensor is fixedly connected to one end of the inner drill rod.

[0013] In some embodiments, the simulated wellbore further includes a bearing, the inner ring of which is fixedly sleeved on the other end of the inner drill pipe, and the outer ring of which is fixed to the second fixing seat.

[0014] In some embodiments, the downhole complex condition simulation device further comprises an inclination adjusting mechanism, the inclination adjusting mechanism comprises a base plate, a fixed frame, a pulley, a winch and a pull rope, one end of the mounting plate is hinged to one end of the base plate, the base plate, the fixed frame and the winch are fixed to the ground, the pulley is rotatably arranged at the upper end of the fixed frame, the pull rope is arranged around the pulley, one end of the pull rope is fixed and arranged around the winding drum of the winch, the other end of the pull rope is fixedly connected with the mounting plate.

[0015] In some embodiments, the drilling fluid injection mechanism comprises a mixing tank, a screw pump, a grouting pipe, a hopper and a rotary sand conveyor, the mixing tank is used for mixing drilling fluid, the inlet of the screw pump is in communication with the outlet of the mixing tank, the outlet of the screw pump is in communication with one end of the grouting pipe, the other end of the grouting pipe is in communication with one end of the outer casing pipe, the hopper is used for loading sand particles, the inlet of the rotary sand conveyor is in communication with the outlet of the hopper, and the outlet of the rotary sand conveyor is in communication with one end of the grouting pipe.

[0016] In some embodiments, the drilling fluid discharge mechanism comprises a discharge pipe and a back pressure valve, one end of the discharge pipe is in communication with the other end of the outer casing pipe, and the back pressure valve is arranged on the discharge pipe.

[0017] In some embodiments, the formation fluid injection mechanism comprises an injection pipe, a plurality of injection sub-pipes, a storage tank, a delivery pump, an injection pipe, an air compressor, a gas storage tank and an injection pipe, one end of the injection pipe is in communication with one end of each of the injection sub-pipes, the other end of each of the injection sub-pipes is in communication with each of the side inlets one by one, each of the injection sub-pipes is provided with an injection valve, one end of the delivery pump is in communication with the storage tank, the other end of the delivery pump is in communication with one end of the injection pipe, the other end of the injection pipe is in communication with the other end of the injection pipe, the outlet of the air compressor is in communication with the inlet of the gas storage tank, the outlet of the gas storage tank is in communication with one end of the injection pipe, and the other end of the injection pipe is in communication with the other end of the injection pipe.

[0018] In some embodiments, the formation fluid discharge mechanism comprises a plurality of discharge sub-pipes and a side discharge pipe, one end of each of the discharge sub-pipes is in communication with each of the side outlets, each of the discharge sub-pipes is provided with a discharge valve, and one end of the side discharge pipe is in communication with the other end of each of the discharge sub-pipes.

[0019] In some embodiments, the downhole complex working condition simulation device further comprises a recycling mechanism, the recycling mechanism comprising a recycling pipe and a solid-liquid separator, one end of the recycling pipe being in communication with the other end of the slurry discharge pipe and the other end of the side discharge pipe, an inlet of the solid-liquid separator being in communication with the other end of the recycling pipe, a solid outlet of the solid-liquid separator being in communication with the inlet of the slurry mixing tank, and a liquid outlet of the solid-liquid separator being in communication with the inlet of the liquid storage tank.

[0020] The application also provides a downhole complex working condition simulation method, comprising the following steps:

[0021] S1, building the downhole complex working condition simulation device;

[0022] S2, keeping the inner drill rod static, injecting the mud into one end of the outer sleeve pipe through the drilling fluid injection mechanism, moving the mud to the other end of the outer sleeve pipe through the annulus between the outer sleeve pipe and the inner drill rod, and then discharging the mud from the other end of the outer sleeve pipe to the drilling fluid discharge mechanism, the drilling fluid discharge mechanism discharging the mud, obtaining the initial temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, and obtaining the initial temperature and pressure distribution of the mud in the outer sleeve pipe, and simultaneously collecting the initial motion state data of the fluid at each position in the outer sleeve pipe by using a high-speed camera;

[0023] S3, rotating the inner drill rod through the rotating mechanism, continuously injecting the mud into one end of the outer sleeve pipe through the drilling fluid injection mechanism, moving the mud to the other end of the outer sleeve pipe through the annulus between the outer sleeve pipe and the inner drill rod, and then discharging the mud from the other end of the outer sleeve pipe to the drilling fluid discharge mechanism, the drilling fluid discharge mechanism discharging the mud, obtaining the first temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor when the mud flow is stable, obtaining the first temperature and pressure distribution of the mud in the outer sleeve pipe, comparing the first temperature and pressure distribution with the initial temperature and pressure distribution, obtaining the influence of the rotation of the inner drill rod on the temperature and pressure distribution, and simultaneously collecting the first motion state data of the fluid at each position in the outer sleeve pipe by using a high-speed camera;

[0024] S4, extruding the inner drill rod through the extruding mechanism to make the inner drill rod bend, obtaining the second temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtaining the second temperature and pressure distribution of the mud in the outer sleeve pipe, comparing the first temperature and pressure distribution with the second temperature and pressure distribution to obtain the influence of the stress and eccentricity of the inner drill rod on the temperature and pressure distribution of the mud in the outer sleeve pipe, and simultaneously collecting the second motion state data of the fluid at each position in the outer sleeve pipe by using a high-speed camera and comparing the second motion state data with the first motion state data;

[0025] S5, opening at least one side inlet, injecting gas into the opened side inlet through the formation fluid injection mechanism, obtaining third temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtaining third temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is not in eccentric state, comparing the first temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing pipe, obtaining the influence of gas invasion on the temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is in eccentric state, comparing the second temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing pipe, obtaining the influence of gas invasion on the temperature and pressure distribution of the mud in the outer casing pipe, and simultaneously collecting third motion state data of the fluid at each position in the outer casing pipe by using a high-speed camera and comparing with the first motion state data;

[0026] S6, opening at least one side inlet, injecting liquid into the opened side inlet through the formation fluid injection mechanism, obtaining fourth temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtaining fourth temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is not in eccentric state, comparing the first temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is in eccentric state, comparing the second temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing pipe, obtaining the influence of liquid invasion on the temperature and pressure distribution of the mud in the outer casing pipe, and simultaneously collecting fourth motion state data of the fluid at each position in the outer casing pipe by using a high-speed camera and comparing with the first motion state data;

[0027] S7, opening at least one side outlet, the mud in the outer casing pipe is discharged from the opened side outlet and enters the formation fluid discharge mechanism, obtaining fifth temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtaining fifth temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is not in eccentric state, comparing the first temperature and pressure distribution and the fifth temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is in eccentric state, comparing the second temperature and pressure distribution and the fifth temperature and pressure distribution of the mud in the outer casing pipe, obtaining the influence of mud loss on the temperature and pressure distribution of the mud in the outer casing pipe, and simultaneously collecting fifth motion state data of the fluid at each position in the outer casing pipe by using a high-speed camera and comparing with the first motion state data;

[0028] S8, simultaneously opening the at least one side inlet and the at least one side outlet, injecting liquid or gas into the opened side inlet through the formation fluid injection mechanism, obtaining the sixth temperature and pressure detected by the first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, obtaining the sixth temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is not in the eccentric state, comparing the first temperature and pressure distribution and the sixth temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is in the eccentric state, comparing the second temperature and pressure distribution and the sixth temperature and pressure distribution of the mud in the outer casing pipe, obtaining the influence of the simultaneous occurrence of fluid invasion and mud loss on the temperature and pressure distribution of the mud in the outer casing pipe, and simultaneously collecting the sixth motion state data of the fluid at each position in the outer casing pipe by using the high-speed camera and comparing with the first motion state data;

[0029] S9, opening the side inlet closest to the injection end of the outer casing pipe, injecting gas into the opened side inlet through the formation fluid injection mechanism, simultaneously injecting mud into one end of the outer casing pipe through the drilling fluid injection mechanism, the mixture of mud and gas moving in the outer casing pipe, obtaining the seventh temperature and pressure detected by the first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor after stabilization, obtaining the seventh temperature and pressure distribution of the mud in the outer casing pipe, obtaining the gas-liquid two-phase migration law in the annulus, and simultaneously collecting the seventh motion state data of the fluid at each position in the outer casing pipe by using the high-speed camera.

[0030] S10, injecting sand-containing mud into one end of the outer casing pipe through the drilling fluid injection mechanism, the mixture of mud and sand moving in the outer casing pipe, obtaining the eighth temperature and pressure detected by the first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor after stabilization, obtaining the eighth temperature and pressure distribution of the mud in the outer casing pipe, obtaining the solid-liquid two-phase migration law in the annulus, and simultaneously collecting the eighth motion state data of the fluid at each position in the outer casing pipe by using the high-speed camera.

[0031] S11, opening the side inlet closest to the injection end of the outer casing pipe, injecting gas into the opened side inlet through the formation fluid injection mechanism, simultaneously injecting sand-containing mud into one end of the outer casing pipe through the drilling fluid injection mechanism, the mixture of mud, sand and gas moving in the outer casing pipe, obtaining the ninth temperature and pressure detected by the first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor after stabilization, obtaining the ninth temperature and pressure distribution of the mud in the outer casing pipe, obtaining the gas-liquid-solid three-phase migration law in the annulus, and simultaneously collecting the ninth motion state data of the fluid at each position in the outer casing pipe by using the high-speed camera.

[0032] Compared with the prior art, the well complex condition simulation device and method have the beneficial effects that: the inner drill rod is used to simulate the drill rod, the outer casing is used to simulate the wellbore, the inner drill rod is driven to rotate by the rotating mechanism, so that the rotation of the drill rod is simulated, the inner drill rod is extruded or stretched by the extruding mechanism, so that the axial pressure received by the drill rod is simulated, the temperature and pressure of the annulus are detected by the first temperature sensor, the first pressure sensor, the second temperature sensor and the second pressure sensor, the drilling fluid injection mechanism is used to inject the mud into one end of the outer casing, the drilling fluid discharge mechanism is used to discharge the mud, so that the mud migration process of the annulus in the actual drilling is simulated, the formation fluid injection mechanism is used to inject the gas or liquid into at least one side inlet, so that the gas invasion or well kick in the actual drilling is simulated, the formation fluid discharge mechanism is used to simulate the loss in the actual drilling, the actual downhole complex condition can be simulated in the laboratory by the device, necessary conditions can be created for the indoor research of the cuttings migration process, the loss circulation, the overflow, the simultaneous occurrence of the loss circulation and the overflow and the three-phase flow process, the device can be used to guide the establishment of the flow model and the drilling operation, in addition, the simulation device adopts the visual design, the fluid circulation process in the downhole which is invisible can be visualized, so that the semi-empirical research is changed into the scientific and quantitative research. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a structural schematic view of a well complex condition simulation device provided by an embodiment of the present application;

[0034] Figure 2 is a structural schematic view of the simulation wellbore and the inclination adjusting mechanism in Figure 1 ;

[0035] Figure 3 is a structural schematic view of the simulation wellbore and the inclination adjusting mechanism in Figure 2 ;

[0036] Figure 4 is a partial enlarged view of the region A in Figure 2 ;

[0037] Figure 5 is a partial enlarged view of the region C in Figure 2 ;

[0038] Figure 6 is a structural schematic view of the drilling fluid injection mechanism and the formation fluid injection mechanism in Figure 1 ;

[0039] Explanation of reference signs: 1-simulated wellbore, 11-mounting plate, 111-linkage, 12-first fixing seat, 13-second fixing seat, 131-bearing, 14-outer sleeve, 1401-tube segment, 1402-connection sleeve, 141-side inlet, 142-side outlet, 143-first temperature sensor and first pressure sensor, 144-second temperature sensor and second pressure sensor, 145-first sealing ring, 146-second sealing ring, 15-inner drill rod, 16-extrusion mechanism, 161-extrusion cylinder, 162-tension sensor, 163-torque sensor, 17-rotation mechanism, 171-rotation motor, 2-drilling fluid injection mechanism, 21-mixing tank, 211-agitator, 212-heater, 22-screw pump, 23-mixing pipe, 231-mixing temperature sensor, 232-mixing pressure sensor, 233-first check valve, 234-mixing flowmeter, 235-mixing densimeter, 24-hopper, 25-rotary sand conveyor, 3-drilling fluid discharge mechanism, 31-discharge pipe, 311-discharge pressure sensor, 312-discharge flowmeter, 32-back pressure valve, 4-formation fluid injection mechanism, 41-injection pipe, 411-fourth check valve, 412-injection flowmeter, 42-injection sub-pipe, 421-injection valve, 43-liquid storage tank, 44-delivery pump, 45-injection pipe, 451-second check valve, 452-injection pressure sensor, 46-air compressor, 47-gas storage tank, 48-gas injection pipe, 481-third check valve, 482-gas injection flowmeter, 483-gas injection pressure sensor, 5-formation fluid discharge mechanism, 51-discharge sub-pipe, 511-discharge valve, 52-side discharge pipe, 6-inclination adjustment mechanism, 61-bottom plate, 62-fixing frame, 63-pulley, 64-winch, 65-pulling rope, 7-reuse mechanism, 71-reuse pipe, 72-solid-liquid separator. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application 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 only used to explain the present application and should not be used to limit the present application.

[0041] Referring to Figure 1 , Figure 1 Figure 1 is a structural schematic diagram of a downhole complex working condition simulation device according to an embodiment of the present application. The downhole complex working condition simulation device comprises a simulated wellbore 1, a drilling fluid injection mechanism 2, a drilling fluid discharge mechanism 3, a formation fluid injection mechanism 4 and a formation fluid discharge mechanism 5.

[0042] Referring to Figures 1-6The simulation wellbore 1 comprises a mounting plate 11, a first fixing base 12, a second fixing base 13, an outer sleeve 14, an inner drill rod 15, a squeezing mechanism 16 and a rotating mechanism 17, the first fixing base 12 and the second fixing base 13 are respectively fixed at two ends of the mounting plate 11, the outer sleeve 14 is fixed on the mounting plate 11, the outer sleeve 14 is provided with a plurality of openable side inlets 141 and a plurality of openable side outlets 142 along the length direction, each side inlet 141 is provided with a first temperature sensor and a first pressure sensor 143, each side outlet 142 is provided with a second temperature sensor and a second pressure sensor 144, the outer sleeve 14 is made of transparent material, a plurality of high-speed cameras are arranged outside the outer sleeve 14, the inner drill rod 15 is arranged in the outer sleeve 14, the fixed end of the rotating mechanism 17 is fixed on the first fixing base 12, the rotating end of the rotating mechanism 17 is connected with the fixed end of the squeezing mechanism 16, and the telescopic end of the squeezing mechanism 16 is fixedly connected with one end of the inner drill rod 15, and the other end of the inner drill rod 15 is rotatably connected with the second fixing base 13.

[0043] The drilling fluid injection mechanism 2 is used for injecting mud into one end of the outer sleeve 14, the drilling fluid discharge mechanism 3 is communicated with the other end of the outer sleeve 14 and is used for discharging drilling fluid, the formation fluid injection mechanism 4 is communicated with each side inlet 141 and is used for injecting gas or liquid into at least one side inlet 141, and the formation fluid discharge mechanism 5 is communicated with each side outlet 142 and is used for discharging gas or liquid discharged by at least one side outlet 142.

[0044] The technical scheme provided by the present application simulates a drill rod by the inner drill rod 15, simulates a wellbore by the outer sleeve 14, rotates the inner drill rod 15 by the rotating mechanism 17, thereby simulating the rotation of the drill rod, squeezes or stretches the inner drill rod 15 by the squeezing mechanism 16, thereby simulating the axial pressure received by the drill rod, detects the temperature and pressure of each part of the annulus by each first temperature sensor and first pressure sensor 143 and second temperature sensor and second pressure sensor 144, injects mud into one end of the outer sleeve 14 by the drilling fluid injection mechanism, discharges mud by the drilling fluid discharge mechanism 3, thereby simulating the mud migration process of the annulus in actual drilling, injects gas or liquid into at least one side inlet 141 by the formation fluid injection mechanism 4, thereby simulating gas invasion or well kick in actual drilling, and simulates loss in actual drilling by the formation fluid discharge mechanism 5.

[0045] In one of the embodiments, please refer toFigure 1 and Figure 5 The outer sleeve 14 is fixed to the mounting plate 11 via several connecting rods 111.

[0046] In one embodiment, please refer to Figure 1 and Figure 5 The outer sleeve 14 comprises several pipe sections 1401 and connecting sleeves 1402, two adjacent pipe sections 1401 are fixed by a connecting sleeve 1402, and the side inlet 141 and the side outlet 142 both start from the connecting sleeve 1402. The inner drill rod 15 is also connected by multi-section pipes.

[0047] In one embodiment, please refer to Figure 2 and Figure 3 The rotating mechanism 17 comprises a rotating motor 171, the housing of the rotating motor 171 is fixed to the other end of the pressure sensor 162. The extruding mechanism 16 comprises an extruding cylinder 161, the cylinder body of the extruding cylinder 161 is fixed to the output shaft of the rotating motor 171, the output shaft of the extruding cylinder 161 is fixedly connected with one end of a tension sensor 162, the other end of the tension sensor 162 is fixedly connected with one end of a torque sensor 163, the other end of the torque sensor 163 is fixedly connected with one end of the inner drill rod 15; in use, the inner drill rod 15 can be rotated by the rotating motor 171, the inner drill rod 15 can be extruded or stretched by the extruding cylinder 161, the corresponding tension can be detected by the tension sensor 162, and the torque of the rotation of the inner drill rod 15 can be detected by the torque sensor 163.

[0048] In one embodiment, please refer to Figure 2 and Figure 4 The simulated wellbore 1 further comprises a bearing 131, the inner ring of the bearing 131 is fixedly sleeved on the other end of the inner drill rod 15 via another tension sensor and another torque sensor, and the outer ring of the bearing 131 is fixed to the second fixing base 13, so that the inner drill rod 15 can be stably rotated.

[0049] In one embodiment, please refer to Figure 1 and Figure 2The downhole complex working condition simulation device further comprises an inclination adjusting mechanism 6, one end of the mounting plate 11 is hingedly connected to one end of a base plate 61, the base plate 61, a fixed frame 62 and a winch 64 are fixed to the ground, a pulley 63 is rotatably arranged at the upper end of the fixed frame 62, a pull rope 65 is arranged around the pulley 63, one end of the pull rope 65 is fixedly arranged around the winding drum of the winch 64, and the other end of the pull rope 65 is fixedly connected with the mounting plate 11. In use, the pull rope 65 can be pulled by the winch 64, so as to adjust the inclination angle of the mounting plate 11, and further adjust the inclination angle of the inner drill rod 15 and the outer casing 14, so as to simulate the inclination angle of the actual wellbore.

[0050] In one of the embodiments, referring to Figures 1-6 The drilling fluid injection mechanism 2 comprises a mixing tank 21, a screw pump 22, a grouting pipe 23, a hopper 24 and a rotary sand feeder 25. The mixing tank 21 is used for preparing the drilling fluid. The inlet of the screw pump 22 is in communication with the outlet of the mixing tank 21. The outlet of the screw pump 22 is in communication with one end of the grouting pipe 23. The other end of the grouting pipe 23 is in communication with one end of the outer casing 14. The hopper 24 is used for loading sand particles. The inlet of the rotary sand feeder 25 is in communication with the outlet of the hopper 24. The outlet of the rotary sand feeder 25 is in communication with one end of the grouting pipe 23. In use, the drilling fluid prepared in the mixing tank 21 can be injected into one end of the outer casing 14 by the screw pump 22. The sand particles can be added into the drilling fluid by the rotary sand feeder 25.

[0051] In one of the embodiments, referring to Figures 1-6 The drilling fluid injection mechanism 2 further comprises a grouting temperature sensor 231, a grouting pressure sensor 232, a first one-way valve 233, a grouting flow meter 234 and a grouting density meter 235 arranged on the grouting pipe 23.

[0052] In one of the embodiments, referring to Figures 1-6 One end of the outer casing 14 is provided with a first sealing ring 145, the first sealing ring 145 is arranged between the inner drill rod 15 and the outer casing 14, and the other end of the grouting pipe 23 penetrates through the first sealing ring 145.

[0053] In one of the embodiments, referring to Figure 1 and Figure 6 The mixing tank 21 is provided with a stirrer 211 and a heater 212, so as to facilitate mixing and heating the drilling fluid to a set temperature.

[0054] In one of the embodiments, referring to Figure 1The drilling fluid discharging mechanism 3 comprises a discharging pipe 31 and a back pressure valve 32. One end of the discharging pipe 31 is communicated with the other end of the outer sleeve 14, and the back pressure valve 32 is arranged on the discharging pipe 31. The pressure in the outer sleeve 14 can be maintained by the back pressure valve 32 to match the actual annular pressure.

[0055] In one embodiment, referring to Figure 1 The discharging pipe 31 is further provided with a discharging pressure sensor 311 and a discharging flow meter 312.

[0056] In one embodiment, referring to Figure 2 and Figure 4 The other end of the outer sleeve 14 is provided with a second sealing ring 146, which is arranged between the inner drill pipe 15 and the outer sleeve 14. One end of the discharging pipe 31 penetrates the second sealing ring 146.

[0057] In one embodiment, referring to Figures 1-6 The formation fluid injecting mechanism 4 comprises a fluid injecting pipe 41, a plurality of injecting sub-pipes 42, a liquid storage tank 43, a delivery pump 44, a liquid injecting pipe 45, an air compressor 46, a gas storage tank 47 and a gas injecting pipe 48. One end of the fluid injecting pipe 41 is communicated with one end of each of the injecting sub-pipes 42. The other end of each of the injecting sub-pipes 42 is communicated with one of the side inlets 141. Each of the injecting sub-pipes 42 is provided with an injecting valve 421. The first temperature sensor and the first pressure sensor 143 are also arranged on the corresponding injecting sub-pipe 42 and located between the injecting valve 421 and the side inlet 141. Thus, the first temperature sensor and the first pressure sensor 143 can detect the temperature and pressure of the side inlet 141 regardless of whether the injecting valve 421 is opened or not. One end of the delivery pump 44 is communicated with the liquid storage tank 43, and the other end of the delivery pump 44 is communicated with one end of the liquid injecting pipe 45. The other end of the liquid injecting pipe 45 is communicated with the other end of the fluid injecting pipe 41. The outlet of the air compressor 46 is communicated with the inlet of the gas storage tank 47. The outlet of the gas storage tank 47 is communicated with one end of the gas injecting pipe 48. The other end of the gas injecting pipe 48 is communicated with the other end of the fluid injecting pipe 41. In use, the liquid in the liquid storage tank 43 can be injected into the side inlet 141 by the delivery pump 44, and the gas can be injected into the side inlet 141 by the air compressor 46.

[0058] In one embodiment, referring to Figure 1 and Figure 6The liquid injection pipe 45 is provided with a second one-way valve 451 and a liquid injection pressure sensor 452, the gas injection pipe 48 is provided with a third one-way valve 481, a gas injection flow meter 482 and a gas injection pressure sensor 483, and the fluid injection pipe 41 is provided with a fourth one-way valve 411 and a fluid injection flow meter 412.

[0059] In one of the embodiments, referring to Figure 1 and Figure 6 The formation fluid discharge mechanism 5 comprises a plurality of discharge sub-pipes 51 and a side discharge pipe 52, one end of each of the discharge sub-pipes 51 is communicated with each of the side outlets 142, each of the discharge sub-pipes 51 is provided with a discharge valve 511, and one end of the side discharge pipe 52 is communicated with the other end of each of the discharge sub-pipes 51. The opening and closing of each of the discharge valves 511 can control the opening and closing of each of the side outlets 142. The second temperature sensor and the second pressure sensor 144 are also arranged on the corresponding discharge sub-pipes 51, and are located between the discharge valves 511 and the side outlets 142, so that the second temperature sensor and the second pressure sensor 144 can always detect the temperature and pressure of the side outlets 142 regardless of whether the discharge valves 511 are opened or not.

[0060] In one of the embodiments, referring to Figure 1 and Figure 6 The downhole complex working condition simulation device further comprises a recycling mechanism 7, the recycling mechanism 7 comprises a recycling pipe 71 and a solid-liquid separator 72, one end of the recycling pipe 71 is communicated with the other end of the slurry discharge pipe 31 and the other end of the side discharge pipe 52, the inlet of the solid-liquid separator 72 is communicated with the other end of the recycling pipe 71, the solid outlet of the solid-liquid separator 72 is communicated with the inlet of the slurry preparation tank 21, and the liquid outlet of the solid-liquid separator 72 is communicated with the inlet of the liquid storage tank 43. In this embodiment, the solid-liquid separator 72 is a vibrating screen, in use, the mud discharged from the slurry discharge pipe 31 and the side discharge pipe 52 enters the recycling pipe 71, and then enters the solid-liquid separator 72, after solid-liquid separation, the solid is transported to the slurry preparation tank 21 for re-preparing drilling fluid, and the liquid is transported to the liquid storage tank 43, so that through the arrangement of the recycling mechanism 7, the recycling of the drilling fluid can be realized.

[0061] The application further provides a downhole complex working condition simulation method, comprising the following steps:

[0062] S1, building the downhole complex working condition simulation device;

[0063] S2, keeping the inner drill pipe 15 static, injecting mud into one end of the outer casing pipe 14 through the drilling fluid injection mechanism 2, the mud moving to the other end of the outer casing pipe 14 through the annulus between the outer casing pipe 14 and the inner drill pipe 15, and then being discharged from the other end of the outer casing pipe 14 to the drilling fluid discharge mechanism 3, the drilling fluid discharge mechanism 3 discharging the mud, obtaining the initial temperature and pressure detected by the first temperature sensor and the first pressure sensor 143 and the second temperature sensor and the second pressure sensor 144 after the mud flow is stable, obtaining the initial temperature and pressure distribution of the mud in the outer casing pipe 14, and collecting the initial motion state data of the fluid at each position in the outer casing pipe by using a high-speed camera;

[0064] S3, rotating the inner drill pipe 15 through the rotating mechanism 17, and continuing to inject mud into one end of the outer casing pipe 14 through the drilling fluid injection mechanism 2, the mud moving to the other end of the outer casing pipe 14 through the annulus between the outer casing pipe 14 and the inner drill pipe 15, and then being discharged from the other end of the outer casing pipe 14 to the drilling fluid discharge mechanism 3, the drilling fluid discharge mechanism 3 discharging the mud, obtaining the first temperature and pressure detected by the first temperature sensor and the first pressure sensor 143 and the second temperature sensor and the second pressure sensor 144 after the mud flow is stable, obtaining the first temperature and pressure distribution of the mud in the outer casing pipe 14, and comparing the first temperature and pressure distribution with the initial temperature and pressure distribution to obtain the influence of the rotation of the inner drill pipe on the temperature and pressure distribution, and collecting the first motion state data of the fluid at each position in the outer casing pipe by using a high-speed camera;

[0065] S4, extruding the inner drill pipe 15 through the extruding mechanism 16 to make the inner drill pipe 15 bend, obtaining the second temperature and pressure detected by the first temperature sensor and the first pressure sensor 143 and the second temperature sensor and the second pressure sensor 144, obtaining the second temperature and pressure distribution of the mud in the outer casing pipe 14, comparing the first temperature and pressure distribution and the second temperature and pressure distribution of the mud in the outer casing pipe 14 to obtain the influence of the stress and eccentricity of the inner drill pipe 15 on the temperature and pressure distribution of the mud in the outer casing pipe 14, and collecting the second motion state data of the fluid at each position in the outer casing pipe by using a high-speed camera, and comparing the second motion state data with the first motion state data;

[0066] S5, open at least one side inlet 141, inject gas into the opened side inlet 141 through the formation fluid injection mechanism 4, obtain the third temperature and pressure detected by each first temperature sensor and first pressure sensor 143 and second temperature sensor and second pressure sensor 144, obtain the third temperature and pressure distribution of the mud in the outer casing pipe 14, if the inner drill pipe is not in eccentric state, compare the first temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing pipe 14, if the inner drill pipe is in eccentric state, compare the second temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing pipe, obtain the influence of gas invasion on the temperature and pressure distribution of the mud in the outer casing pipe 14, and at the same time, use the high-speed camera to collect the third motion state data of the fluid at each position in the outer casing pipe, and compare with the first motion state data;

[0067] S6, open at least one side inlet 141, inject liquid into the opened side inlet 141 through the formation fluid injection mechanism 4, obtain the fourth temperature and pressure detected by each first temperature sensor and first pressure sensor 143 and second temperature sensor and second pressure sensor 144, obtain the fourth temperature and pressure distribution of the mud in the outer casing pipe 14, if the inner drill pipe is not in eccentric state, compare the first temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing pipe 14, if the inner drill pipe is in eccentric state, compare the second temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing pipe, obtain the influence of liquid invasion on the temperature and pressure distribution of the mud in the outer casing pipe 14, and at the same time, use the high-speed camera to collect the fourth motion state data of the fluid at each position in the outer casing pipe, and compare with the first motion state data;

[0068] S7, open at least one side outlet 142, the mud in the outer casing pipe 14 is discharged from the opened side outlet 142 and enters the formation fluid discharge mechanism 5, obtain the fifth temperature and pressure detected by each first temperature sensor and first pressure sensor 143 and second temperature sensor and second pressure sensor 144, obtain the fifth temperature and pressure distribution of the mud in the outer casing pipe 14, if the inner drill pipe is not in eccentric state, compare the first temperature and pressure distribution and the fifth temperature and pressure distribution of the mud in the outer casing pipe 14, if the inner drill pipe is in eccentric state, compare the second temperature and pressure distribution and the fifth temperature and pressure distribution of the mud in the outer casing pipe, obtain the influence of mud loss on the temperature and pressure distribution of the mud in the outer casing pipe 14, and at the same time, use the high-speed camera to collect the fifth motion state data of the fluid at each position in the outer casing pipe, and compare with the first motion state data;

[0069] S8, simultaneously open at least one side inlet 141 and at least one side outlet 142, inject liquid or gas into the opened side inlet 141 through the formation fluid injection mechanism 4, obtain the sixth temperature and pressure detected by each first temperature sensor and first pressure sensor 143 and second temperature sensor and second pressure sensor 144, obtain the sixth temperature and pressure distribution of the mud in the outer casing pipe 14, if the inner drill pipe is not in the eccentric state, if the inner drill pipe is in the eccentric state, compare the second temperature and pressure distribution and the sixth temperature and pressure distribution of the mud in the outer casing pipe, compare the first temperature and pressure distribution and the sixth temperature and pressure distribution of the mud in the outer casing pipe 14, obtain the influence of the simultaneous occurrence of fluid invasion and mud loss on the temperature and pressure distribution of the mud in the outer casing pipe 14, and simultaneously collect the sixth motion state data of the fluid at each position in the outer casing pipe using a high-speed camera and compare with the first motion state data;

[0070] S9, open the side inlet 141 closest to the injection end of the outer casing pipe 14, inject gas into the opened side inlet 141 through the formation fluid injection mechanism 4, and simultaneously inject mud into one end of the outer casing pipe 14 through the drilling fluid injection mechanism 2, the mixture of mud and gas moves in the outer casing pipe 14, and after stabilization, the seventh temperature and pressure detected by each first temperature sensor and first pressure sensor 143 and second temperature sensor and second pressure sensor 144 is obtained, the seventh temperature and pressure distribution of the mud in the outer casing pipe 14 is obtained, and the gas-liquid two-phase migration law in the annulus (i.e. the region between the inner drill pipe 15 and the outer casing pipe 14) is obtained, and simultaneously the seventh motion state data of the fluid at each position in the outer casing pipe is collected using a high-speed camera;

[0071] S10, inject sand-containing mud into one end of the outer casing pipe 14 through the drilling fluid injection mechanism 2, the mixture of mud and sand moves in the outer casing pipe 14, and after stabilization, the eighth temperature and pressure detected by each first temperature sensor and first pressure sensor 143 and second temperature sensor and second pressure sensor 144 is obtained, the eighth temperature and pressure distribution of the mud in the outer casing pipe 14 is obtained, and the solid-liquid two-phase migration law in the annulus is obtained, and simultaneously the eighth motion state data of the fluid at each position in the outer casing pipe is collected using a high-speed camera;

[0072] S11, open the side inlet 141 closest to the injection end of the outer casing pipe 14, inject gas into the opened side inlet 141 through the formation fluid injection mechanism 4, and simultaneously inject sand-containing mud into one end of the outer casing pipe 14 through the drilling fluid injection mechanism 2, the mixture of mud, sand and gas moves in the outer casing pipe 14, and after stabilization, the ninth temperature and pressure detected by each first temperature sensor and first pressure sensor 143 and second temperature sensor and second pressure sensor 144 is obtained, the ninth temperature and pressure distribution of the mud in the outer casing pipe 14 is obtained, and the gas-liquid-solid three-phase migration law in the annulus is obtained, and simultaneously the ninth motion state data of the fluid at each position in the outer casing pipe is collected using a high-speed camera.

[0073] In the above steps S2-S10, the fluid state of the outer sleeve at each position is continuously photographed by the high-speed camera, and comparative analysis is performed to assist in judgment.

[0074] In summary, the technical scheme provided by the present application, through the inner drill rod 15 simulates the drill rod, through the outer sleeve 14 simulates the wellbore, through the rotating mechanism 17 drives the inner drill rod 15 to rotate, thereby simulating the rotation of the drill rod, through the extrusion mechanism 16 extrudes or stretches the inner drill rod 15, thereby simulating the axial pressure received by the drill rod, through the annulus temperature and pressure detection mechanism 1 detects the temperature and pressure of the annulus at each position, through the drilling fluid injection mechanism injects mud into one end of the outer sleeve 14, through the drilling fluid discharge mechanism 3 discharges the mud, thereby simulating the mud migration process of the annulus during actual drilling, through the formation fluid injection mechanism 4 injects gas or liquid into at least one of the side inlets 141, thereby simulating gas invasion or well kick during actual drilling, through the formation fluid discharge mechanism 5 simulates the loss of circulation during actual drilling, through the device, the actual downhole complex working conditions can be simulated in the laboratory, which can create necessary conditions for indoor research of the process of cuttings migration, well leakage, overflow, simultaneous occurrence of well leakage and overflow, and three-phase flow process, and can be used to guide the establishment of flow model and drilling operation. In addition, the simulation device adopts visual design, which can visualize the fluid circulation process that is invisible downhole, thereby changing the semi-empirical research into scientific and quantitative research.

[0075] The specific embodiments of the present application described above do not constitute a limitation on the scope of protection of the present application. Any various other corresponding changes and modifications made according to the technical concept of the present application shall be included in the scope of protection of the claims of the present application.

Claims

1. A downhole complex condition simulation device, characterized in that, The simulation wellbore comprises a mounting plate, a first fixing seat, a second fixing seat, an outer sleeve, an inner drill rod, a squeezing mechanism and a rotating mechanism, the first fixing seat and the second fixing seat are respectively fixed at two ends of the mounting plate, the outer sleeve is fixed to the mounting plate, the outer sleeve has a plurality of openable side inlets and a plurality of openable side outlets along the length direction, each side inlet is provided with a first temperature sensor and a first pressure sensor, each side outlet is provided with a second temperature sensor and a second pressure sensor, the outer sleeve is made of transparent material, a plurality of high-speed cameras are arranged outside the outer sleeve, the inner drill rod is arranged in the outer sleeve, the fixed end of the rotating mechanism is fixed to the first fixing seat, the rotating end of the rotating mechanism is connected with the fixed end of the squeezing mechanism, the telescopic end of the squeezing mechanism is fixedly connected with one end of the inner drill rod, the other end of the inner drill rod is rotatably connected with the second fixing seat. A drilling fluid injection mechanism is arranged for injecting mud into one end of the outer sleeve. A drilling fluid discharge mechanism is arranged in communication with the other end of the outer sleeve and is used for discharging drilling fluid. A formation fluid injection mechanism is arranged in communication with each side inlet and is used for injecting gas or liquid into at least one side inlet. A formation fluid discharge mechanism is arranged in communication with each side outlet and is used for discharging gas or liquid discharged from at least one side outlet. The rotating mechanism comprises a rotating motor, and the shell of the rotating motor is fixed to the first fixing seat.

2. The downhole complex condition simulation device of claim 1, wherein, The squeezing mechanism comprises a squeezing cylinder, the output shaft of the rotating motor is fixedly connected with the cylinder body of the squeezing cylinder, the output shaft of the squeezing cylinder is fixedly connected with one end of a tension sensor, the other end of the tension sensor is fixedly connected with one end of a torque sensor, and the other end of the torque sensor is fixedly connected with one end of the inner drill rod. The simulation wellbore further comprises a bearing, the inner ring of the bearing is fixedly sleeved on the other end of the inner drill rod, and the outer ring of the bearing is fixed to the second fixing seat.

3. The downhole complex condition simulation device of claim 1, wherein, The simulation wellbore further comprises an inclination adjusting mechanism, the inclination adjusting mechanism comprises a base plate, a fixing frame, a pulley, a winch and a pull rope, one end of the mounting plate is hingedly connected to one end of the base plate, the base plate, the fixing frame and the winch are fixed to the ground, the pulley is rotatably arranged at the upper end of the fixing frame, the pull rope is wound around the pulley, one end of the pull rope is fixedly wound around the winding drum of the winch, and the other end of the pull rope is fixedly connected with the mounting plate.

4. The downhole complex condition simulation device of claim 1, wherein, ​ 5. The downhole complex condition simulation device of claim 1, wherein, The drilling fluid injection mechanism comprises a mixing tank, a screw pump, a grouting pipe, a hopper and a rotary sand conveyor, the mixing tank is used for mixing drilling fluid, an inlet of the screw pump is communicated with an outlet of the mixing tank, an outlet of the screw pump is communicated with one end of the grouting pipe, the other end of the grouting pipe is communicated with one end of the outer sleeve, the hopper is used for loading sand particles, an inlet of the rotary sand conveyor is communicated with an outlet of the hopper, and an outlet of the rotary sand conveyor is communicated with one end of the grouting pipe.

6. The downhole complex condition simulation device of claim 5, wherein, The drilling fluid discharge mechanism comprises a discharge pipe and a back pressure valve, one end of the discharge pipe is communicated with the other end of the outer sleeve, and the back pressure valve is arranged on the discharge pipe.

7. The downhole complex condition simulation device of claim 6, wherein, The formation fluid injection mechanism comprises an injection pipe, a plurality of injection sub-pipes, a liquid storage tank, a delivery pump, an injection pipe, an air compressor, a gas storage tank and a gas injection pipe, one end of the injection pipe is communicated with one end of each of the injection sub-pipes, the other end of each of the injection sub-pipes is communicated with each of the side inlets one by one, each of the injection sub-pipes is provided with an injection valve, one end of the delivery pump is communicated with the liquid storage tank, the other end of the delivery pump is communicated with one end of the injection pipe, the other end of the injection pipe is communicated with the other end of the injection pipe, the outlet of the air compressor is communicated with the inlet of the gas storage tank, the outlet of the gas storage tank is communicated with one end of the gas injection pipe, and the other end of the gas injection pipe is communicated with the other end of the injection pipe.

8. The downhole complex condition simulation device of claim 7, wherein, The formation fluid discharge mechanism comprises a plurality of discharge sub-pipes and a side discharge pipe, one end of each of the discharge sub-pipes is communicated with each of the side outlets, each of the discharge sub-pipes is provided with a discharge valve, and one end of the side discharge pipe is communicated with the other end of each of the discharge sub-pipes.

9. The downhole complex condition simulation device of claim 8, wherein, The reuse mechanism comprises a reuse pipe and a solid-liquid separator, one end of the reuse pipe is communicated with the other end of the discharge pipe and the other end of the side discharge pipe, the inlet of the solid-liquid separator is communicated with the other end of the reuse pipe, the solid outlet of the solid-liquid separator is communicated with the inlet of the mixing tank, and the liquid outlet of the solid-liquid separator is communicated with the inlet of the liquid storage tank.

10. A method of simulating downhole complex conditions, characterized by, The method comprises the following steps: S1, building the downhole complex condition simulation device according to any one of claims 1-9; S2, keeping the inner drill rod still, injecting mud into one end of the outer sleeve through the drilling fluid injection mechanism, moving the mud from the annulus between the outer sleeve and the inner drill rod to the other end of the outer sleeve, and then discharging the mud from the other end of the outer sleeve to the drilling fluid discharge mechanism, discharging the mud by the drilling fluid discharge mechanism, obtaining the initial temperature and pressure detected by each first temperature sensor and first pressure sensor and each second temperature sensor and second pressure sensor, and obtaining the initial temperature and pressure distribution of the mud in the outer sleeve, and collecting the initial motion state data of the fluid at each position in the outer sleeve by using a high-speed camera; S3, rotating the inner drill pipe by the rotating mechanism, meanwhile, continuing to inject the mud into one end of the outer casing pipe by the drilling fluid injection mechanism, the mud moves to the other end of the outer casing pipe through the annulus between the outer casing pipe and the inner drill pipe, and then is discharged from the other end of the outer casing pipe to the drilling fluid discharge mechanism, the drilling fluid discharge mechanism discharges the mud, when the mud flow is stable, obtaining the first temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtaining the first temperature and pressure distribution of the mud in the outer casing pipe, and comparing with the initial temperature and pressure distribution, obtaining the influence of the rotation of the inner drill pipe on the temperature and pressure distribution, and simultaneously using the high-speed camera to collect the first motion state data of the fluid at each position in the outer casing pipe; S4, extruding the inner drill pipe by the extruding mechanism, so that the inner drill pipe is bent, obtaining the second temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtaining the second temperature and pressure distribution of the mud in the outer casing pipe, comparing the first temperature and pressure distribution and the second temperature and pressure distribution of the mud in the outer casing pipe, obtaining the influence of the stress and eccentricity of the inner drill pipe on the temperature and pressure distribution of the mud in the outer casing pipe, and simultaneously using the high-speed camera to collect the second motion state data of the fluid at each position in the outer casing pipe, and comparing with the first motion state data; S5, opening at least one side inlet, injecting gas into the opened side inlet by the formation fluid injection mechanism, obtaining the third temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtaining the third temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is not in the eccentric state, comparing the first temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is in the eccentric state, comparing the second temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing pipe, obtaining the influence of the gas invasion on the temperature and pressure distribution of the mud in the outer casing pipe, and simultaneously using the high-speed camera to collect the third motion state data of the fluid at each position in the outer casing pipe, and comparing with the first motion state data; S6, opening at least one side inlet, injecting liquid into the opened side inlet by the formation fluid injection mechanism, obtaining the fourth temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtaining the fourth temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is not in the eccentric state, comparing the first temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing pipe, if the inner drill pipe is in the eccentric state, comparing the second temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing pipe, obtaining the influence of the liquid invasion on the temperature and pressure distribution of the mud in the outer casing pipe, and simultaneously using the high-speed camera to collect the fourth motion state data of the fluid at each position in the outer casing pipe, and comparing with the first motion state data; S7, open at least one side outlet, the mud in the outer sleeve is discharged from the opened side outlet and enters the formation fluid discharge mechanism, acquire the fifth temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtain the fifth temperature and pressure distribution of the mud in the outer sleeve, if the inner drill rod is not in eccentric state, compare the first temperature and pressure distribution and the fifth temperature and pressure distribution of the mud in the outer sleeve, if the inner drill rod is in eccentric state, compare the second temperature and pressure distribution and the fifth temperature and pressure distribution of the mud in the outer sleeve, obtain the influence of mud loss on the temperature and pressure distribution of the mud in the outer sleeve, at the same time, use the high-speed camera to collect the fifth motion state data of the fluid at each position in the outer sleeve, and compare with the first motion state data; S8, open at least one side inlet and at least one side outlet at the same time, inject liquid or gas into the opened side inlet through the formation fluid injection mechanism, acquire the sixth temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtain the sixth temperature and pressure distribution of the mud in the outer sleeve, if the inner drill rod is not in eccentric state, compare the first temperature and pressure distribution and the sixth temperature and pressure distribution of the mud in the outer sleeve, if the inner drill rod is in eccentric state, compare the second temperature and pressure distribution and the sixth temperature and pressure distribution of the mud in the outer sleeve, obtain the influence of fluid invasion and mud loss occurring at the same time on the temperature and pressure distribution of the mud in the outer sleeve, at the same time, use the high-speed camera to collect the sixth motion state data of the fluid at each position in the outer sleeve, and compare with the first motion state data; S9, open the side inlet closest to the injection end of the outer sleeve, inject gas into the opened side inlet through the formation fluid injection mechanism, at the same time, inject mud into one end of the outer sleeve through the drilling fluid injection mechanism, the mixture of mud and gas moves in the outer sleeve, after stabilization, acquire the seventh temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtain the seventh temperature and pressure distribution of the mud in the outer sleeve, obtain the gas-liquid two-phase migration law in the annulus, at the same time, use the high-speed camera to collect the seventh motion state data of the fluid at each position in the outer sleeve; S10, inject mud containing sand particles into one end of the outer sleeve through the drilling fluid injection mechanism, the mixture of mud and sand particles moves in the outer sleeve, after stabilization, acquire the eighth temperature and pressure detected by each first temperature sensor and first pressure sensor and second temperature sensor and second pressure sensor, obtain the eighth temperature and pressure distribution of the mud in the outer sleeve, obtain the solid-liquid two-phase migration law in the annulus, at the same time, use the high-speed camera to collect the eighth motion state data of the fluid at each position in the outer sleeve; S11, opening the side entrance closest to the injection end of the outer sleeve, injecting gas into the opened side entrance through the formation fluid injection mechanism, and injecting the sand-containing mud into one end of the outer sleeve through the drilling fluid injection mechanism, the mixture of the mud, sand and gas moving in the outer sleeve, obtaining the ninth temperature and pressure detected by the first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor after stabilization, obtaining the ninth temperature and pressure distribution of the mud in the outer sleeve, obtaining the gas-liquid-solid three-phase migration law in the annulus, and collecting the ninth motion state data of the fluid at each position in the outer sleeve by using a high-speed camera.

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