Underground complex working condition simulation device and method

Abstract

The invention discloses an underground complex working condition simulation device and method, the device comprises a simulation shaft, a drilling fluid injection mechanism, a drilling fluid discharge mechanism, a formation fluid injection mechanism and a formation fluid discharge mechanism, the simulation shaft comprises a mounting plate, a first fixing seat, a second fixing seat, an outer sleeve, an inner drill rod, an extrusion mechanism and a rotating mechanism; the drilling fluid injection mechanism is used for injecting slurry into one end of the outer sleeve. The device has the advantages that gas or liquid is injected into at least one side inlet through the formation fluid injection mechanism, so that gas cut or well kick during actual well drilling is simulated, leakage during actual well drilling is simulated through the formation fluid discharge mechanism, actual underground complex working conditions can be simulated in a laboratory through the device, and the working efficiency is improved. The method can create necessary conditions for indoor research of a rock debris migration process, well leakage, overflow, simultaneous occurrence of well leakage and overflow, and a three-phase flow process, and can be used for guiding establishment of a flow model and drilling construction.

Description

Technical Field

[0001] The invention relates to the technical field of drilling engineering, and in particular to a device and method for simulating complex underground working conditions. Background Art

[0002] Flow circulation refers to the complete flow process of drilling fluid (mud) pumped from the wellhead by the drilling pump through the drilling string, drill bit, annulus and back to the ground mud pool. It is the basis for drilling implementation. However, due to the complexity of downhole conditions and the hidden nature of downhole risks, there are many complex working conditions in the flow circulation during drilling, including: (1) The field of drilling exploration is gradually moving towards deep layers and deep waters. High temperature and high pressure are currently common complex downhole working conditions. Circulating fluids are mostly non-Newtonian fluids, and their rheological properties change significantly with temperature and pressure (temperature and pressure). The flow laws of fluids under different temperature and pressure conditions will change; (2) During the drilling process, rock fragments are generated due to rock breaking and need to be carried out of the well through the wellbore fluid circulation. During the circulation and carrying process, the cuttings will exist in the wellbore in a suspended state or a cuttings bed state, and the suspended cuttings will change the flow. The density of the body, the cuttings bed will change the size of the wellbore flow channel and thus change the flow state in the wellbore; (3) In the actual circulation process, overflow, well leakage or overflow may occur simultaneously. Sudden fluid intrusion, outflow or exchange will change the flow state of the fluid in the wellbore; at the same time, since the invading fluid does not completely match the composition of the original circulating fluid in the wellbore, the physical properties of the original circulating fluid will change; (4) During the drilling process, when drilling into different formations, due to different construction conditions and drilling rig status, the stress condition of the drill pipe will change, which may cause the drill pipe to bend. Changes in the shape of the drill pipe will also affect the flow state of the drilling fluid in the annulus.

[0003] Since the underground is an invisible blind area, it is difficult to monitor the flow state of the wellbore and analyze the flow law by relying solely on the sensors currently arranged at the wellhead and bottom of the well. It is even more difficult to scientifically handle the abnormal flow of the wellbore, which may lead to serious underground accidents and increase construction costs and operational risks. Therefore, it is necessary to study the flow change law caused by various complex working conditions during the underground circulation flow process, establish a visual multifunctional experimental bench, and scientifically guide the establishment of flow models and drilling construction. However, there is no simulation method and device with such multifunctionality. Summary of the invention

[0004] The purpose of the present invention is to overcome the above technical deficiencies and to propose a device and method for simulating downhole complex working conditions in order to study the flow change laws caused by various complex working conditions during downhole circulation flow.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] The present invention provides a device for simulating complex underground working conditions, comprising:

[0007] A simulated wellbore, the simulated wellbore comprising a mounting plate, a first fixed seat, a second fixed seat, an outer sleeve, an inner drill rod, an extrusion mechanism and a rotating mechanism, the first fixed seat and the second fixed seat are respectively fixed to the two ends of the mounting plate, the outer sleeve is fixed to the mounting plate, the outer sleeve is provided with a plurality of openable and closable side inlets and a plurality of openable and closable side outlets along the length direction, each of the side inlets is provided with a first temperature sensor and a first pressure sensor, each of the side outlets is provided with a second temperature sensor and a second pressure sensor, the outer sleeve is made of a transparent material, a plurality of 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 extrusion mechanism, the telescopic end of the extrusion mechanism is fixedly connected to one end of the inner drill rod, and the other end of the inner drill rod is rotationally connected to the second fixed seat;

[0008] A drilling fluid injection mechanism, the drilling fluid injection mechanism is used to inject mud into one end of the outer casing;

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

[0010] A formation fluid injection mechanism, the formation fluid injection mechanism is connected to each of the side inlets and is used to inject gas or liquid into at least one of the side inlets; a formation fluid discharge mechanism, the formation fluid discharge mechanism is connected to each of the side outlets and is used to discharge the 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, the rotation mechanism includes a rotary motor, and the housing of the rotary motor is fixed to the first fixing seat;

[0012] The extrusion mechanism includes an extrusion cylinder and a pressure sensor. The output shaft of the rotating 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, an inner ring of the bearing is fixedly sleeved on the other end of the inner drill rod, and an outer ring of the bearing is fixed to the second fixing seat.

[0014] In some embodiments, the underground complex working condition simulation device also includes an inclination adjustment mechanism, which includes 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, and the base plate, the fixed frame and the winch are all fixed to the ground. The pulley is rotatably arranged at the upper end of the fixed frame, and the pull rope is wound around the pulley. One end of the pull rope is fixed and wound around the drum of the winch, and the other end of the pull rope is fixedly connected to the mounting plate.

[0015] In some embodiments, the drilling fluid injection mechanism includes a slurry preparation tank, a screw pump, a grouting pipe, a hopper and a rotary sand conveyor. The slurry preparation tank is used to prepare drilling fluid, the inlet of the screw pump is connected to the outlet of the slurry preparation tank, the outlet of the screw pump is connected to one end of the grouting pipe, the other end of the grouting pipe is connected to one end of the outer casing, the hopper is used to load sand, the inlet of the rotary sand conveyor is connected to the outlet of the hopper, and the outlet of the rotary sand conveyor is connected to one end of the grouting pipe.

[0016] In some embodiments, the drilling fluid discharge mechanism includes a slurry discharge pipe and a back pressure valve, one end of the slurry discharge pipe is connected to the other end of the outer casing, and the back pressure valve is arranged on the slurry discharge pipe.

[0017] In some embodiments, the formation fluid injection mechanism includes an injection pipe, a plurality of injection branch pipes, a liquid storage tank, a delivery pump, an injection pipe, an air compressor, an air storage tank and an air injection pipe, one end of the injection pipe is connected to one end of each of the injection branch pipes, the other end of each of the injection branch pipes is connected to each of the side inlets in a one-to-one correspondence, each of the injection branch pipes is provided with an injection valve, one end of the delivery pump is connected to the liquid storage tank, the other end of the delivery pump is connected to one end of the injection pipe, the other end of the injection pipe is connected to the other end of the injection pipe, the outlet of the air compressor is connected to the inlet of the air storage tank, the outlet of the air storage tank is connected to one end of the air injection pipe, and the other end of the air injection pipe is connected to the other end of the injection pipe.

[0018] In some embodiments, the formation fluid discharge mechanism includes a plurality of discharge branch pipes and side discharge pipes, one end of each of the discharge branch pipes is connected to each of the side outlets, each of the discharge branch pipes is provided with a discharge valve, and one end of the side discharge pipe is connected to the other end of each of the discharge branch pipes.

[0019] In some embodiments, the downhole complex working condition simulation device also includes a recycling mechanism, which includes a recycling pipe and a solid-liquid separator, one end of the recycling pipe is connected to the other end of the slurry discharge pipe and the other end of the side discharge pipe, the inlet of the solid-liquid separator is connected to the other end of the recycling pipe, the solid outlet of the solid-liquid separator is connected to the inlet of the slurry preparation tank, and the liquid outlet of the solid-liquid separator is connected to the inlet of the liquid storage tank.

[0020] The present invention also provides a method for simulating complex underground working conditions, comprising the following steps:

[0021] S1. Build the underground complex working condition simulation device;

[0022] S2, keeping the inner drill pipe stationary, injecting mud into one end of the outer casing through the drilling fluid injection mechanism, the mud moves to the other end of the outer casing through the annulus between the outer casing and the inner drill pipe, and then is discharged from the other end of the outer casing to the drilling fluid discharge mechanism, the drilling fluid discharge mechanism discharges the mud, when the mud flow is stable, obtaining the initial temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, obtaining the initial temperature and pressure distribution of the mud in the outer casing, and at the same time using a high-speed camera to collect the initial motion state data of the fluid at each position in the outer casing;

[0023] S3, driving the inner drill pipe to rotate through the rotating mechanism, and at the same time, continuing to inject mud into one end of the outer casing through the drilling fluid injection mechanism, the mud moves to the other end of the outer casing through the annulus between the outer casing and the inner drill pipe, and then is discharged from the other end of the outer casing to the drilling fluid discharge mechanism, and the drilling fluid discharge mechanism discharges the mud. When the mud flow is stable, the first temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor are obtained to obtain the first temperature and pressure distribution of the mud in the outer casing, and compared with the initial temperature and pressure distribution, the influence of the rotation of the inner drill pipe on the temperature and pressure distribution is obtained, and at the same time, the first motion state data of the fluid at each position in the outer casing is collected by using a high-speed camera;

[0024] S4, squeezing the inner drill rod by means of a squeezing mechanism to bend the inner drill rod, obtaining the second temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, obtaining the second temperature and pressure distribution of the mud in the outer casing, comparing the first temperature and pressure distribution of the mud in the outer casing with the second temperature and pressure distribution, obtaining the influence of the stress condition and eccentricity of the inner drill rod on the temperature and pressure distribution of the mud in the outer casing, and simultaneously collecting the second motion state data of the fluid at each position in the outer casing by means of a high-speed camera, and comparing it with the first motion state data;

[0025] S5, open at least one side inlet, inject gas into the opened side inlet through the formation fluid injection mechanism, obtain the third temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, and obtain the third temperature and pressure distribution of the mud in the outer casing; if the inner drill rod is not in an eccentric state, compare the first temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing to obtain the influence of gas invasion on the temperature and pressure distribution of the mud in the outer casing; if the inner drill rod is in an eccentric state, compare the second temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing to obtain the influence of gas invasion on the temperature and pressure distribution of the mud in the outer casing; and at the same time, use a high-speed camera to collect the third motion state data of the fluid at each position in the outer casing, and compare it with the first motion state data;

[0026] S6, open at least one side inlet, inject liquid into the opened side inlet through the formation fluid injection mechanism, obtain the fourth temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, and obtain the fourth temperature and pressure distribution of the mud in the outer casing, if the inner drill rod is not in an eccentric state, compare the first temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing, if the inner drill rod is in an eccentric state, compare the second temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing, and obtain the influence of liquid intrusion on the temperature and pressure distribution of the mud in the outer casing, and at the same time use a high-speed camera to collect the fourth motion state data of the fluid at each position in the outer casing, and compare it with the first motion state data;

[0027] S7, open at least one side outlet, the mud in the outer casing is discharged from the opened side outlet and enters the formation fluid discharge mechanism, the fifth temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor are obtained, and the fifth temperature and pressure distribution of the mud in the outer casing is obtained. If the inner drill rod is not in an eccentric state, the first temperature and pressure distribution of the mud in the outer casing is compared with the fifth temperature and pressure distribution. If the inner drill rod is in an eccentric state, the second temperature and pressure distribution of the mud in the outer casing is compared with the fifth temperature and pressure distribution, and the influence of mud loss on the temperature and pressure distribution of the mud in the outer casing is obtained. At the same time, the fifth motion state data of the fluid at each position in the outer casing is collected by a high-speed camera, and compared with the first motion state data;

[0028] S8, simultaneously opening at least one side inlet and 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 each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, and obtaining the sixth temperature and pressure distribution of the mud in the outer casing, and if the inner drill rod is not in an eccentric state, comparing the first temperature and pressure distribution of the mud in the outer casing with the sixth temperature and pressure distribution, and if the inner drill rod is in an eccentric state, comparing the second temperature and pressure distribution of the mud in the outer casing with the sixth temperature and pressure distribution, and obtaining the influence of the simultaneous occurrence of fluid intrusion and mud loss on the temperature and pressure distribution of the mud in the outer casing, and at the same time using a high-speed camera to collect the sixth motion state data of the fluid at each position in the outer casing, and comparing it with the first motion state data;

[0029] S9, opening the side inlet closest to the injection end of the outer casing, injecting gas into the opened side inlet through the formation fluid injection mechanism, and injecting mud into one end of the outer casing through the drilling fluid injection mechanism, so that the mixture of mud and gas moves in the outer casing, and after stabilization, the seventh temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor are obtained to obtain the seventh temperature and pressure distribution of the mud in the outer casing, and the gas-liquid two-phase migration law in the annulus is obtained, and at the same time, the seventh motion state data of the fluid at each position in the outer casing is collected by using a high-speed camera;

[0030] S10, injecting mud containing sand into one end of the outer casing through the drilling fluid injection mechanism, and the mixture of mud and sand moves in the outer casing. After stabilization, the eighth temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor are obtained to obtain the eighth temperature and pressure distribution of the mud in the outer casing, and the solid-liquid two-phase migration law in the annulus is obtained, and at the same time, the eighth movement state data of the fluid at each position in the outer casing is collected by using a high-speed camera;

[0031] S11. Open the side inlet closest to the injection end of the outer casing, inject gas into the opened side inlet through the formation fluid injection mechanism, and at the same time inject mud containing sand particles into one end of the outer casing through the drilling fluid injection mechanism. The mixture of mud, sand particles and gas moves in the outer casing. After stabilization, 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 are obtained to obtain the ninth temperature and pressure distribution of the mud in the outer casing, and the gas-liquid-solid three-phase migration law in the annulus is obtained. At the same time, the ninth motion state data of the fluid at each position in the outer casing are collected by a high-speed camera.

[0032] Compared with the prior art, the device and method for simulating downhole complex working conditions provided by the present invention have the following beneficial effects: the drill rod is simulated by the inner drill rod, the wellbore is simulated by the outer casing, the inner drill rod is driven to rotate by the rotating mechanism, thereby simulating the rotation of the drill rod, the inner drill rod is squeezed or stretched by the squeezing mechanism, thereby simulating the axial pressure on the drill rod, the temperature and pressure of each part of the annulus are detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, mud is injected into one end of the outer casing by the drilling fluid injection mechanism, and the mud is discharged by the drilling fluid discharge mechanism, thereby simulating the mud migration process in the annulus during actual drilling, Gas or liquid is injected into at least one of the side inlets through the formation fluid injection mechanism, thereby simulating gas invasion or well kick during actual drilling, and the leakage during actual drilling is simulated through the formation fluid discharge mechanism. The device can simulate actual complex underground working conditions in the laboratory, and can create necessary conditions for indoor research on cuttings migration process, well leakage, overflow, simultaneous occurrence of well leakage and overflow, and three-phase flow process. It can be used to guide the establishment of flow models and drilling construction. In addition, the simulation device adopts a visual design, which can visualize the invisible fluid circulation process in the well, thereby transforming semi-empirical research into scientific and quantitative research. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of a downhole complex working condition simulation device provided by an embodiment of the present invention;

[0034] Figure 2 yes Figure 1 The structural diagram of the simulated wellbore and the inclination adjustment mechanism;

[0035] Figure 3 yes Figure 2 A partial enlarged view of the middle area A;

[0036] Figure 4 yes Figure 2 A partial enlarged view of the middle area B;

[0037] Figure 5 yes Figure 2 A partial enlarged view of the middle area C;

[0038] Figure 6 yes Figure 1 A schematic diagram of the structure of the drilling fluid injection mechanism and the formation fluid injection mechanism;

[0039] Description of reference numerals: 1-simulated wellbore, 11-mounting plate, 111-connecting rod, 12-first fixing seat, 13-second fixing seat, 131-bearing, 14-outer sleeve, 1401-pipe joint, 1402-connecting 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-slurry mixing tank, 211-agitator, 212-heater, 22-screw pump, 23-grouting pipe, 231-grouting temperature sensor, 232-grouting pressure sensor, 233-first one-way valve, 234-grouting flowmeter, 235-grouting density meter, 24-hopper, 25-rotary sand conveyor, 3-drilling fluid discharge mechanism, 31-slurry discharge pipe, 311-slurry discharge pressure sensor, 312-slurry discharge flowmeter, 32-back pressure valve, 4-formation fluid injection mechanism, 41-injection fluid pipe, 411-fourth one-way valve, 412-injection fluid flowmeter, 42-injection branch pipe, 421-injection valve, 43-liquid storage tank, 44-delivery pump, 45-injection pipe, 451-second one-way valve, 452-injection hydraulic Force sensor, 46-air compressor, 47-gas storage tank, 48-gas injection pipe, 481-third one-way valve, 482-gas injection flowmeter, 483-gas injection pressure sensor, 5-formation fluid discharge mechanism, 51-discharge branch pipe, 511-discharge valve, 52-side discharge pipe, 6-inclination adjustment mechanism, 61-bottom plate, 62-fixed frame, 63-pulley, 64-winch, 65-pull rope, 7-recycling mechanism, 71-recycling pipe, 72-solid-liquid separator. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] See also Figure 1 , Figure 1 This is a schematic diagram of the structure of a device for simulating complex downhole working conditions in one embodiment of the present invention. The device for simulating complex downhole working conditions includes 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] See also Figure 1-Figure 6The simulated wellbore 1 includes a mounting plate 11, a first fixing seat 12, a second fixing seat 13, an outer sleeve 14, an inner drill rod 15, an extrusion mechanism 16 and a rotation mechanism 17. The first fixing seat 12 and the second fixing seat 13 are respectively fixed to the two ends of the mounting plate 11. The outer sleeve 14 is fixed to the mounting plate 11. The outer sleeve 14 has a plurality of openable and closable side inlets 141 and a plurality of openable and closable side outlets 142 along the length direction. Each of the side inlets 141 is installed with a first temperature sensor and a first pressure sensor 143. Each The side outlets 142 are each installed with a second temperature sensor and a second pressure sensor 144. The outer sleeve 14 is made of a transparent material. Several high-speed cameras are arranged on the outside of the outer sleeve 14. The inner drill rod 15 is built into the outer sleeve 14. The fixed end of the rotating mechanism 17 is fixed to the first fixed seat 12. The rotating end of the rotating mechanism 17 is connected to the fixed end of the extrusion mechanism 16. The telescopic end of the extrusion mechanism 16 is fixedly connected to one end of the inner drill rod 15. The other end of the inner drill rod 15 is rotatably connected to the second fixed seat 13.

[0043] The drilling fluid injection mechanism 2 is used to inject mud into one end of the outer casing 14; the drilling fluid discharge mechanism 3 is connected to the other end of the outer casing 14 and is used to discharge the drilling fluid; the formation fluid injection mechanism 4 is connected to each of the side inlets 141, and is used to inject gas or liquid into at least one of the side inlets 141; the formation fluid discharge mechanism 5 is connected to each of the side outlets 142, and is used to discharge the gas or liquid discharged from at least one of the side outlets 142.

[0044] The technical solution provided by the present invention simulates the drill rod through the inner drill rod 15, simulates the wellbore through the outer casing 14, drives the inner drill rod 15 to rotate through the rotating mechanism 17, thereby simulating the rotation of the drill rod, squeezes or stretches the inner drill rod 15 through the squeezing mechanism 16, thereby simulating the axial pressure on the drill rod, detects the temperature and pressure of each part of the annulus through each first temperature sensor and the first pressure sensor 143 and the second temperature sensor and the second pressure sensor 144, injects mud into one end of the outer casing 14 through the drilling fluid injection mechanism, and discharges the mud through the drilling fluid discharge mechanism. The mud is discharged through the formation fluid discharge mechanism 3, thereby simulating the mud migration process in the annulus during actual drilling, and gas or liquid is injected into at least one of the side inlets 141 through the formation fluid injection mechanism 4, thereby simulating gas invasion or well kick during actual drilling, and the leakage during actual drilling is simulated through the formation fluid discharge mechanism 5. The device can simulate actual complex downhole working conditions in the laboratory, and can create necessary conditions for indoor research on the cuttings migration process, 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 models and drilling construction.

[0045] In one embodiment, see Figure 1 and Figure 5 The outer sleeve 14 is fixed to the mounting plate 11 via a plurality of connecting rods 111 .

[0046] In one embodiment, see Figure 1 and Figure 5 The outer casing 14 includes a plurality of pipe sections 1401 and a connecting sleeve 1402. Two adjacent pipe sections 1401 are fixed by the connecting sleeve 1402. The side inlet 141 and the side outlet 142 both start from the connecting sleeve 1402. The inner drill pipe 15 is also formed by connecting multiple sections of pipes.

[0047] In one embodiment, see Figure 2 and Figure 3 The rotating mechanism 17 includes a rotating motor 171, and the housing of the rotating motor 171 is fixed to the other end of the pressure sensor 162. The squeezing mechanism 16 includes an squeezing cylinder 161, and the cylinder body of the squeezing cylinder 161 is fixed to the output shaft of the rotating motor 171. The output shaft of the squeezing cylinder 161 is fixedly connected to one end of a tension sensor 162, and the other end of the tension sensor 162 is fixedly connected to one end of a torque sensor 163, and the other end of the torque sensor 163 is fixedly connected to one end of the inner drill rod 15; when in use, the inner drill rod 15 can be driven to rotate by the rotating motor 171, and the inner drill rod 15 can be squeezed or stretched by the squeezing cylinder 161, and the corresponding tension can be detected by the tension sensor 162, and the torque sensor 163 can detect the torque of the inner drill rod 15.

[0048] In one embodiment, see Figure 2 and Figure 4 The simulated wellbore 1 also includes a bearing 131, the inner ring of the bearing 131 is fixedly mounted 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 fixed seat 13, so that the inner drill rod 15 can rotate stably.

[0049] In one embodiment, see Figure 1 and Figure 2The underground complex working condition simulation device also includes an inclination adjustment mechanism 6, which includes a base plate 61, a fixed frame 62, a pulley 63, a winch 64 and a pull rope 65. One end of the mounting plate 11 is hinged to one end of the base plate 61, and the base plate 61, the fixed frame 62 and the winch 64 are all fixed to the ground. The pulley 63 is rotatably arranged on the upper end of the fixed frame 62. The pull rope 65 is wound around the pulley 63. One end of the pull rope 65 is fixed and wound around the drum of the winch 64, and the other end of the pull rope 65 is fixedly connected to the mounting plate 11. When in use, the pull rope 65 can be pulled by the winch 64 to adjust the inclination angle of the mounting plate 11, thereby adjusting the inclination angle of the inner drill pipe 15 and the outer casing 14 to simulate the inclination angle of the actual wellbore.

[0050] In one embodiment, see Figure 1-Figure 6 The drilling fluid injection mechanism 2 includes a slurry preparation tank 21, a screw pump 22, a grouting pipe 23, a hopper 24 and a rotary sand conveyor 25. The slurry preparation tank 21 is used to prepare drilling fluid. The inlet of the screw pump 22 is connected to the outlet of the slurry preparation tank 21, the outlet of the screw pump 22 is connected to one end of the grouting pipe 23, the other end of the grouting pipe 23 is connected to one end of the outer casing 14, the hopper 24 is used to load sand particles, the inlet of the rotary sand conveyor 25 is connected to the outlet of the hopper 24, and the outlet of the rotary sand conveyor 25 is connected to one end of the grouting pipe 23. When in use, the drilling fluid prepared in the slurry preparation tank 21 can be injected into one end of the outer casing 14 through the screw pump 22, and sand particles can also be added to the drilling fluid through the rotary sand conveyor 25.

[0051] In one embodiment, see Figure 1-Figure 6 The drilling fluid injection mechanism 2 also includes a grouting temperature sensor 231 , a grouting pressure sensor 232 , a first one-way valve 233 , a grouting flowmeter 234 and a grouting density meter 235 which are arranged on the grouting pipe 23 .

[0052] In one embodiment, see Figure 1-Figure 6 One end of the outer sleeve 14 is plugged with a first sealing ring 145 , the first sealing ring 145 is arranged between the inner drill rod 15 and the outer sleeve 14 , and the other end of the grouting pipe 23 passes through the first sealing ring 145 .

[0053] In one embodiment, see Figure 1 and Figure 6 The slurry preparation tank 21 is provided with an agitator 211 and a heater 212, so as to facilitate mixing the drilling fluid and heating the drilling fluid to a set temperature.

[0054] In one embodiment, see Figure 1The drilling fluid discharge mechanism 3 includes a slurry discharge pipe 31 and a back pressure valve 32. One end of the slurry discharge pipe 31 is connected to the other end of the outer casing 14. The back pressure valve 32 is arranged on the slurry discharge pipe 31. The back pressure valve 32 can maintain the pressure in the outer casing 14 to match the actual annulus pressure.

[0055] In one embodiment, see Figure 1 The slurry discharge pipe 31 is also provided with a slurry discharge pressure sensor 311 and a slurry discharge flow meter 312 .

[0056] In one embodiment, see Figure 2 and Figure 4 The other end of the outer sleeve 14 is plugged with a second sealing ring 146 , the second sealing ring 146 is arranged between the inner drill rod 15 and the outer sleeve 14 , and one end of the slurry discharge pipe 31 passes through the second sealing ring 146 .

[0057] In one embodiment, see Figure 1-Figure 6 The formation fluid injection mechanism 4 includes a fluid injection pipe 41, a plurality of injection branch pipes 42, a liquid storage tank 43, a delivery pump 44, a fluid injection pipe 45, an air compressor 46, an air storage tank 47 and an air injection pipe 48. One end of the fluid injection pipe 41 is connected to one end of each of the injection branch pipes 42, and the other end of each of the injection branch pipes 42 is connected to each of the side inlets 141 in a one-to-one correspondence. Each of the injection branch pipes 42 is provided with an injection valve 421, and a first temperature sensor and a first pressure sensor 143 are also provided on the corresponding injection branch pipe 42, and the first temperature sensor and the first pressure sensor 143 are located at the injection valve 42. 1 and the side inlet 141, so that no matter whether the injection valve 421 is opened or not, the first temperature sensor and the first pressure sensor 143 can always detect the temperature and pressure of the side inlet 141, one end of the delivery pump 44 is connected to the liquid storage tank 43, the other end of the delivery pump 44 is connected to one end of the injection pipe 45, the other end of the injection pipe 45 is connected to the other end of the fluid injection pipe 41, the outlet of the air compressor 46 is connected to the inlet of the gas storage tank 47, the outlet of the gas storage tank 47 is connected to one end of the gas injection pipe 48, and the other end of the gas injection pipe 48 is connected to the other end of the fluid injection pipe 41. When in use, the liquid in the liquid storage tank 43 can be injected into the side inlet 141 through the delivery pump 44, and the gas can also be injected into the side inlet 141 through the air compressor 46.

[0058] In one embodiment, see 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 flowmeter 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 flowmeter 412.

[0059] In one embodiment, see Figure 1 and Figure 6 The formation fluid discharge mechanism 5 includes a plurality of discharge branch pipes 51 and a side discharge pipe 52. One end of each of the discharge branch pipes 51 is connected to each of the side outlets 142. Each of the discharge branch pipes 51 is provided with a discharge valve 511. One end of the side discharge pipe 52 is connected to the other end of each of the discharge branch pipes 51. The opening and closing of each of the side outlets 142 can be controlled by opening and closing each of the discharge valves 511. The second temperature sensor and the second pressure sensor 144 are also provided on the corresponding discharge branch pipe 51, and the second temperature sensor and the second pressure sensor 144 are located between the discharge valve 511 and the side outlet 142. In this way, no matter whether the discharge valve 511 is opened or not, the second temperature sensor and the second pressure sensor 144 can always detect the temperature and pressure of the side outlet 142.

[0060] In one embodiment, see Figure 1 and Figure 6 The downhole complex working condition simulation device also includes a recycling mechanism 7, which includes a recycling pipe 71 and a solid-liquid separator 72. One end of the recycling pipe 71 is connected to 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 connected to the other end of the recycling pipe 71. The solid outlet of the solid-liquid separator 72 is connected to the inlet of the slurry preparation tank 21, and the liquid outlet of the solid-liquid separator 72 is connected to the inlet of the liquid storage tank 43. In this embodiment, the solid-liquid separator 72 is a vibrating screen. When in use, the slurry 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 reconfiguring the drilling fluid, and the liquid is transported to the liquid storage tank 43. Therefore, by setting the recycling mechanism 7, the recycling of the drilling fluid can be achieved.

[0061] The present invention also provides a method for simulating complex underground working conditions, comprising the following steps:

[0062] S1. Build the underground complex working condition simulation device;

[0063] S2, keep the inner drill pipe 15 still, inject mud into one end of the outer casing 14 through the drilling fluid injection mechanism 2, the mud moves to the other end of the outer casing 14 through the annulus between the outer casing 14 and the inner drill pipe 15, and then is discharged from the other end of the outer casing 14 to the drilling fluid discharge mechanism 3, the drilling fluid discharge mechanism 3 discharges the mud, and when the mud flow is stable, obtain the initial temperature and pressure detected by each first temperature sensor and the first pressure sensor 143 and the second temperature sensor and the second pressure sensor 144, obtain the initial temperature and pressure distribution of the mud in the outer casing 14, and use a high-speed camera to collect the initial motion state data of the fluid at each position in the outer casing;

[0064] S3, driving the inner drill pipe 15 to rotate through the rotating mechanism 17, and at the same time, continuing to inject mud into one end of the outer casing 14 through the drilling fluid injection mechanism 2, the mud moves to the other end of the outer casing 14 through the annulus between the outer casing 14 and the inner drill pipe 15, and then is discharged from the other end of the outer casing 14 to the drilling fluid discharge mechanism 3, the drilling fluid discharge mechanism 3 discharges the mud, and when the mud flow is stable, the first temperature and pressure detected by each first temperature sensor and the first pressure sensor 143 and the second temperature sensor and the second pressure sensor 144 are obtained, and the first temperature and pressure distribution of the mud in the outer casing 14 is obtained, and compared with the initial temperature and pressure distribution, the influence of the rotation of the inner drill pipe on the temperature and pressure distribution is obtained, and at the same time, the first motion state data of the fluid at each position in the outer casing is collected by a high-speed camera;

[0065] S4, squeezing the inner drill rod 15 by the squeezing mechanism 16 to bend the inner drill rod 15, obtaining the second temperature and pressure detected by each 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 14, comparing the first temperature and pressure distribution of the mud in the outer casing 14 with the second temperature and pressure distribution, obtaining the influence of the stress condition and eccentricity of the inner drill rod 15 on the temperature and pressure distribution of the mud in the outer casing 14, and at the same time using a high-speed camera to collect the second motion state data of the fluid at each position in the outer casing, and comparing it 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 the first pressure sensor 143 and the second temperature sensor and the second pressure sensor 144, and obtain the third temperature and pressure distribution of the mud in the outer casing 14; if the inner drill rod is not in an eccentric state, compare the first temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing 14; if the inner drill rod is in an eccentric state, compare the second temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing to obtain the influence of gas intrusion on the temperature and pressure distribution of the mud in the outer casing 14; and at the same time, use a high-speed camera to collect the third motion state data of the fluid at each position in the outer casing, and compare it 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 the first pressure sensor 143 and the second temperature sensor and the second pressure sensor 144, and obtain the fourth temperature and pressure distribution of the mud in the outer casing 14; if the inner drill rod is not in an eccentric state, compare the first temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing 14; if the inner drill rod is in an eccentric state, compare the second temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing to obtain the influence of liquid intrusion on the temperature and pressure distribution of the mud in the outer casing 14; and at the same time, use a high-speed camera to collect the fourth motion state data of the fluid at each position in the outer casing, and compare it with the first motion state data;

[0068] S7, open at least one side outlet 142, the mud in the outer casing 14 is discharged from the opened side outlet 142 and enters the formation fluid discharge mechanism 5, the fifth temperature and pressure detected by each first temperature sensor and the first pressure sensor 143 and the second temperature sensor and the second pressure sensor 144 are obtained, and the fifth temperature and pressure distribution of the mud in the outer casing 14 is obtained. If the inner drill rod is not in an eccentric state, the first temperature and pressure distribution of the mud in the outer casing 14 is compared with the fifth temperature and pressure distribution. If the inner drill rod is in an eccentric state, the second temperature and pressure distribution of the mud in the outer casing is compared with the fifth temperature and pressure distribution, and the influence of mud leakage on the temperature and pressure distribution of the mud in the outer casing 14 is obtained. At the same time, the fifth motion state data of the fluid at each position in the outer casing is collected by a high-speed camera, and compared with the first motion state data;

[0069] S8, simultaneously opening at least one side inlet 141 and at least one side outlet 142, injecting liquid or gas into the opened side inlet 141 through the formation fluid injection mechanism 4, obtaining the sixth temperature and pressure detected by each first temperature sensor and the first pressure sensor 143 and the second temperature sensor and the second pressure sensor 144, and obtaining the sixth temperature and pressure distribution of the mud in the outer casing 14, if the inner drill rod is not in an eccentric state, if the inner drill rod is in an eccentric state, then comparing the second temperature and pressure distribution of the mud in the outer casing with the sixth temperature and pressure distribution, and comparing the first temperature and pressure distribution of the mud in the outer casing 14 with the sixth temperature and pressure distribution, 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 14, and at the same time using a high-speed camera to collect the sixth motion state data of the fluid at each position in the outer casing, and comparing it with the first motion state data;

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

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

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

[0073] In the above steps S2-S10, the fluid state at various locations of the outer sleeve is continuously photographed by a high-speed camera for comparative analysis to assist in the determination.

[0074] In summary, the technical solution provided by the present invention simulates the drill rod through the inner drill rod 15, simulates the wellbore through the outer casing 14, drives the inner drill rod 15 to rotate through the rotating mechanism 17, thereby simulating the rotation of the drill rod, squeezes or stretches the inner drill rod 15 through the squeezing mechanism 16, thereby simulating the axial pressure on the drill rod, detects the temperature and pressure of various parts of the annulus through each first temperature sensor and the first pressure sensor 143 and the second temperature sensor and the second pressure sensor 144, injects mud into one end of the outer casing 14 through the drilling fluid injection mechanism, and discharges the mud through the drilling fluid discharge mechanism 3, thereby simulating the mud migration process in the annulus during actual drilling, Gas or liquid is injected into at least one of the side inlets 141 through the formation fluid injection mechanism 4, thereby simulating gas invasion or well kick during actual drilling, and the leakage during actual drilling is simulated through the formation fluid discharge mechanism 5. This device can simulate actual complex underground working conditions in the laboratory, and can create necessary conditions for indoor research on cuttings migration process, well leakage, overflow, simultaneous occurrence of well leakage and overflow, and three-phase flow process. It can be used to guide the establishment of flow models and drilling construction. In addition, this simulation device adopts a visual design, which can visualize the invisible fluid circulation process in the well, thereby transforming semi-empirical research into scientific and quantitative research.

[0075] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A device for simulating complex underground working conditions, characterized in that: include: A simulated wellbore, the simulated wellbore comprising a mounting plate, a first fixed seat, a second fixed seat, an outer sleeve, an inner drill rod, an extrusion mechanism and a rotating mechanism, the first fixed seat and the second fixed seat are respectively fixed to the two ends of the mounting plate, the outer sleeve is fixed to the mounting plate, the outer sleeve is provided with a plurality of openable and closable side inlets and a plurality of openable and closable side outlets along the length direction, each of the side inlets is provided with a first temperature sensor and a first pressure sensor, each of the side outlets is provided with a second temperature sensor and a second pressure sensor, the outer sleeve is made of a transparent material, a plurality of 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 extrusion mechanism, the telescopic end of the extrusion mechanism is fixedly connected to one end of the inner drill rod, and the other end of the inner drill rod is rotationally connected to the second fixed seat; A drilling fluid injection mechanism, the drilling fluid injection mechanism is used to inject mud into one end of the outer casing; A drilling fluid discharge mechanism, the drilling fluid discharge mechanism is connected to the other end of the outer casing and is used to discharge the drilling fluid; a formation fluid injection mechanism, the formation fluid injection mechanism being in communication with each of the side inlets and being used to inject gas or liquid into at least one of the side inlets; A formation fluid discharge mechanism 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.

2. The downhole complex working condition simulation device according to claim 1, characterized in that: The rotating mechanism comprises a rotating motor, and the housing of the rotating motor is fixed to the first fixing seat; The extrusion mechanism includes an extrusion cylinder, the output shaft of the rotating 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, and the other end of the torque sensor is fixedly connected to one end of the inner drill rod.

3. The downhole complex working condition simulation device according to claim 1, characterized in that: The simulated wellbore also includes a bearing, an inner ring of the bearing is fixedly sleeved on the other end of the inner drill rod, and an outer ring of the bearing is fixed on the second fixing seat.

4. The downhole complex working condition simulation device according to claim 1, characterized in that: It also includes an inclination adjustment mechanism, which includes a base plate, a fixing 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 fixing frame and the winch are all fixed to the ground, the pulley is rotatably arranged on the upper end of the fixing frame, the pull rope is wound around the pulley, one end of the pull rope is fixed and wound around the drum of the winch, and the other end of the pull rope is fixedly connected to the mounting plate.

5. The downhole complex working condition simulation device according to claim 1, characterized in that: The drilling fluid injection mechanism includes a slurry preparation tank, a screw pump, a grouting pipe, a hopper and a rotary sand conveyor. The slurry preparation tank is used to prepare drilling fluid, the inlet of the screw pump is connected to the outlet of the slurry preparation tank, the outlet of the screw pump is connected to one end of the grouting pipe, the other end of the grouting pipe is connected to one end of the outer casing, the hopper is used to load sand particles, the inlet of the rotary sand conveyor is connected to the outlet of the hopper, and the outlet of the rotary sand conveyor is connected to one end of the grouting pipe.

6. The downhole complex working condition simulation device according to claim 5, characterized in that: The drilling fluid discharge mechanism comprises a slurry discharge pipe and a back pressure valve. One end of the slurry discharge pipe is communicated with the other end of the outer casing, and the back pressure valve is arranged on the slurry discharge pipe.

7. The downhole complex working condition simulation device according to claim 6, characterized in that: The formation fluid injection mechanism includes an injection pipe, a plurality of injection branch pipes, a liquid storage tank, a delivery pump, an injection pipe, an air compressor, an air storage tank and an air injection pipe, one end of the injection pipe is connected to one end of each of the injection branch pipes, the other end of each of the injection branch pipes is connected to each of the side inlets in a one-to-one correspondence, and each of the injection branch pipes is provided with an injection valve, one end of the delivery pump is connected to the liquid storage tank, the other end of the delivery pump is connected to one end of the injection pipe, the other end of the injection pipe is connected to the other end of the injection pipe, the outlet of the air compressor is connected to the inlet of the air storage tank, the outlet of the air storage tank is connected to one end of the air injection pipe, and the other end of the air injection pipe is connected to the other end of the injection pipe.

8. The downhole complex working condition simulation device according to claim 7, characterized in that: The formation fluid discharge mechanism includes a plurality of discharge branch pipes and side discharge pipes, one end of each of the discharge branch pipes is connected to each of the side outlets, each of the discharge branch pipes is provided with a discharge valve, and one end of the side discharge pipe is connected to the other end of each of the discharge branch pipes.

9. The downhole complex working condition simulation device according to claim 8, characterized in that: It also includes a recycling mechanism, which includes a recycling pipe and a solid-liquid separator. One end of the recycling pipe is connected to the other end of the slurry discharge pipe and the other end of the side discharge pipe. The inlet of the solid-liquid separator is connected to the other end of the recycling pipe. The solid outlet of the solid-liquid separator is connected to the inlet of the slurry preparation tank, and the liquid outlet of the solid-liquid separator is connected to the inlet of the liquid storage tank.

10. A method for simulating complex underground working conditions, characterized in that: The steps include: S1. Build a downhole complex working condition simulation device as described in any one of claims 1 to 9; S2, keeping the inner drill pipe stationary, injecting mud into one end of the outer casing through the drilling fluid injection mechanism, the mud moves to the other end of the outer casing through the annulus between the outer casing and the inner drill pipe, and then is discharged from the other end of the outer casing to the drilling fluid discharge mechanism, the drilling fluid discharge mechanism discharges the mud, when the mud flow is stable, obtaining the initial temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, obtaining the initial temperature and pressure distribution of the mud in the outer casing, and at the same time using a high-speed camera to collect the initial motion state data of the fluid at each position in the outer casing; S3, driving the inner drill pipe to rotate through the rotating mechanism, and at the same time, continuing to inject mud into one end of the outer casing through the drilling fluid injection mechanism, the mud moves to the other end of the outer casing through the annulus between the outer casing and the inner drill pipe, and then is discharged from the other end of the outer casing to the drilling fluid discharge mechanism, and the drilling fluid discharge mechanism discharges the mud. When the mud flow is stable, the first temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor are obtained to obtain the first temperature and pressure distribution of the mud in the outer casing, and compared with the initial temperature and pressure distribution, the influence of the rotation of the inner drill pipe on the temperature and pressure distribution is obtained, and at the same time, the first motion state data of the fluid at each position in the outer casing is collected by using a high-speed camera; S4, squeezing the inner drill rod by means of a squeezing mechanism to bend the inner drill rod, obtaining the second temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, obtaining the second temperature and pressure distribution of the mud in the outer casing, comparing the first temperature and pressure distribution of the mud in the outer casing with the second temperature and pressure distribution, obtaining the influence of the stress condition and eccentricity of the inner drill rod on the temperature and pressure distribution of the mud in the outer casing, and simultaneously collecting the second motion state data of the fluid at each position in the outer casing by means of a high-speed camera, and comparing it with the first motion state data; S5, open at least one side inlet, inject gas into the opened side inlet through the formation fluid injection mechanism, obtain the third temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, and obtain the third temperature and pressure distribution of the mud in the outer casing, if the inner drill rod is not in an eccentric state, compare the first temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing, if the inner drill rod is in an eccentric state, compare the second temperature and pressure distribution and the third temperature and pressure distribution of the mud in the outer casing, and obtain the influence of gas invasion on the temperature and pressure distribution of the mud in the outer casing, and at the same time use a high-speed camera to collect the third motion state data of the fluid at each position in the outer casing, and compare it with the first motion state data; S6, open at least one side inlet, inject liquid into the opened side inlet through the formation fluid injection mechanism, obtain the fourth temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, and obtain the fourth temperature and pressure distribution of the mud in the outer casing, if the inner drill rod is not in an eccentric state, compare the first temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing, if the inner drill rod is in an eccentric state, compare the second temperature and pressure distribution and the fourth temperature and pressure distribution of the mud in the outer casing, and obtain the influence of liquid intrusion on the temperature and pressure distribution of the mud in the outer casing, and at the same time use a high-speed camera to collect the fourth motion state data of the fluid at each position in the outer casing, and compare it with the first motion state data; S7, open at least one side outlet, the mud in the outer casing is discharged from the opened side outlet and enters the formation fluid discharge mechanism, the fifth temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor are obtained, and the fifth temperature and pressure distribution of the mud in the outer casing is obtained. If the inner drill rod is not in an eccentric state, the first temperature and pressure distribution of the mud in the outer casing is compared with the fifth temperature and pressure distribution. If the inner drill rod is in an eccentric state, the second temperature and pressure distribution of the mud in the outer casing is compared with the fifth temperature and pressure distribution, and the influence of mud loss on the temperature and pressure distribution of the mud in the outer casing is obtained. At the same time, the fifth motion state data of the fluid at each position in the outer casing is collected by a high-speed camera, and compared with the first motion state data; S8, simultaneously opening at least one side inlet and 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 each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor, and obtaining the sixth temperature and pressure distribution of the mud in the outer casing, and if the inner drill rod is not in an eccentric state, comparing the first temperature and pressure distribution of the mud in the outer casing with the sixth temperature and pressure distribution, and if the inner drill rod is in an eccentric state, comparing the second temperature and pressure distribution of the mud in the outer casing with the sixth temperature and pressure distribution, and obtaining the influence of the simultaneous occurrence of fluid intrusion and mud loss on the temperature and pressure distribution of the mud in the outer casing, and at the same time using a high-speed camera to collect the sixth motion state data of the fluid at each position in the outer casing, and comparing it with the first motion state data; S9, opening the side inlet closest to the injection end of the outer casing, injecting gas into the opened side inlet through the formation fluid injection mechanism, and injecting mud into one end of the outer casing through the drilling fluid injection mechanism, so that the mixture of mud and gas moves in the outer casing, and after stabilization, the seventh temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor are obtained to obtain the seventh temperature and pressure distribution of the mud in the outer casing, and the gas-liquid two-phase migration law in the annulus is obtained, and at the same time, the seventh motion state data of the fluid at each position in the outer casing is collected by using a high-speed camera; S10, injecting mud containing sand into one end of the outer casing through the drilling fluid injection mechanism, and the mixture of mud and sand moves in the outer casing. After stabilization, the eighth temperature and pressure detected by each first temperature sensor and the first pressure sensor and the second temperature sensor and the second pressure sensor are obtained to obtain the eighth temperature and pressure distribution of the mud in the outer casing, and the solid-liquid two-phase migration law in the annulus is obtained, and at the same time, the eighth movement state data of the fluid at each position in the outer casing is collected by using a high-speed camera; S11. Open the side inlet closest to the injection end of the outer casing, inject gas into the opened side inlet through the formation fluid injection mechanism, and at the same time inject mud containing sand particles into one end of the outer casing through the drilling fluid injection mechanism. The mixture of mud, sand particles and gas moves in the outer casing. After stabilization, 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 are obtained to obtain the ninth temperature and pressure distribution of the mud in the outer casing, and the gas-liquid-solid three-phase migration law in the annulus is obtained. At the same time, the ninth motion state data of the fluid at each position in the outer casing are collected by a high-speed camera.

Images