Real-time monitoring system and monitoring method for vibration-CO2 corrosion coupling effect of well cementation cement sheath of oil and gas well in high-temperature and high-pressure environment

Abstract

The invention discloses a vibration-CO2 corrosion coupling effect real-time monitoring system and monitoring method for a well cementation cement sheath of an oil and gas well in a high-temperature and high-pressure environment. The system comprises a kettle system which is fixed with a base of an axial loading system, and a push rod of the axial loading system extends into the kettle system from the center of a kettle cover and is pressed on a detected body; the CT detection system is mounted below a jack supporting plate of the axial loading system; the electrolytic corrosion system is connected with the lower end of a first embedded axial pipeline on the side wall of a kettle body in the kettle system so as to apply an experimental environment; the gas pressurization system is divided into two paths, one path is led into the kettle system from the lower part, and the other path is connected with the lower end of the second embedded axial pipeline; a sleeve of the kettle system is fixed in the kettle system, the nondestructive testing system is installed in the middle of the sleeve, and the vibration system in the sleeve is installed on the lower portion of the sleeve. According to the invention, axial loading, gas pressurization and heating devices are integrated, and an underground high-temperature and high-pressure environment is simulated; and CT and ultrasonic waves cooperate to realize multi-dimensional dynamic monitoring of the corrosion process.

Description

Technical Field

[0001] The present invention belongs to the technical field of testing or analyzing materials by measuring the chemical or physical properties of materials, and specifically provides a real-time monitoring system and method for the vibration-CO2 corrosion coupling effect of the cement ring of an oil and gas well in a high-temperature and high-pressure environment, which is applied in the field of oil and gas well engineering. Background Art

[0002] In oil and gas well cementing projects, the durability and CO2 corrosion resistance of the cement sheath between the wellbore and casing are crucial to wellbore integrity. Vibration cementing can improve the durability and CO2 corrosion resistance of the cement sheath. Currently, static immersion tests or conventional autoclave tests are primarily used to evaluate the performance of cement sheaths in CO2-corrosive environments. While these methods can simulate downhole environments, they have limitations such as long experimental cycles, an inability to simulate realistic in-situ stress conditions, and difficulty in achieving vibration-corrosion coupling. Summary of the Invention

[0003] In view of the shortcomings of the existing cement sheath corrosion detection technology in the background technology, with the goal of accurately simulating the high-temperature and high-pressure vibration environment downhole and monitoring the corrosion process in real time, the present invention designs a real-time monitoring system and monitoring method for the vibration-CO2 corrosion coupling effect of the cement sheath of oil and gas well cementing in the high-temperature and high-pressure environment. The technical scheme includes: a kettle system, an axial loading system, a vibration system in the casing, an electrolytic corrosion system, a gas pressurization system and a non-destructive testing system; wherein the kettle system is fixed to the base of the axial loading system, and the push rod of the axial loading system extends into the kettle system from the center of the kettle cover and presses on the object to be tested; the CT detection system is installed below the jack support plate of the axial loading system; the electrolytic corrosion system is connected to the lower end of the first embedded axial pipe on the side wall of the kettle body in the kettle system to apply the experimental environment; the gas pressurization system is divided into two paths, one of which enters the kettle system from the bottom, and the other is connected to the lower end of the second embedded axial pipe; the casing of the kettle system is fixed in the kettle system, the non-destructive testing system is installed in the middle of the casing, and the vibration system in the casing is installed at the lower part of the casing;

[0004] The CT detection system includes a telescopic cylinder, a motor support plate, a CT frame rotating gear, a CT mounting frame, an X-ray generator, an X-ray receiving target, a small motor, a driving gear and a linear bearing; wherein the piston rod of the telescopic cylinder is threadedly connected to the motor support plate, the linear bearing is sleeved on the outside of the guide shaft section of the kettle cover, so that the entire CT device is driven to slide along the guide shaft section of the kettle cover by the telescopic drive of the cylinder piston rod, the linear bearing is connected to the CT mounting frame through a slewing bearing, the CT frame rotating gear is fixedly installed on the CT mounting frame, and the axes of the CT frame rotating gear, slewing bearing and linear bearing are coaxial; the motor support plate and the linear bearing are fixed; the small motor is fixed on the motor support plate, and its output shaft is fixed to the driving gear, which is meshed with the CT frame rotating gear for transmission, and the CT mounting frame is driven to rotate around the center of the kettle body by the rotation of the motor; the X-ray generator and the X-ray receiving target are symmetrically installed on both sides of the bottom of the CT mounting frame, and spiral CT scanning of the object to be detected in the center of the kettle body is achieved through coordinated rotational motion and axial movement.

[0005] The kettle system includes: a kettle body, a kettle cover, a first sealing ring, a sleeve, a second sealing ring, a cement ring, a rock ring, a third sealing ring, a heating sleeve, a temperature sensor, an electronic pressure relief valve and an annulus, a first embedded axial pipe, and a second embedded axial pipe; the kettle body and the kettle cover are connected by bolts, and the first sealing ring is arranged at the junction of the two to ensure sealing; the kettle cover is divided into a sealing area and a guide shaft section; two annular grooves are provided at the bottom of the kettle body, respectively for installing the sleeve and the rock ring for positional fixation, the second sealing ring is installed in the first annular groove to achieve sealing between the sleeve and the kettle body, and the third sealing ring is installed in the second annular groove to achieve sealing between the rock ring and the kettle body; the temperature sensor and the electronic pressure relief valve are integrated and installed at a designated position of the kettle cover; the sleeve, cement ring and rock ring together constitute the object to be detected; the area between the object to be detected and the inner wall of the kettle body is the annulus, and the side wall of the kettle body is integrated with two groups of first embedded and second embedded axial pipes arranged from bottom to top for liquid intake and air intake respectively; the heating sleeve is installed at the outer bottom of the kettle body.

[0006] The axial loading system includes a base, a pillar, a jack support plate, a jack, a pressure sensor, a push rod and a circular seal; the base is used to fix the kettle body, and is connected to the two pillars by bolts to ensure structural stability; the top of the pillar is fixedly connected to the jack support plate by bolts, and the jack is installed on the jack support plate by bolts and is provided with a support reaction force; the pressure sensor is arranged below the jack, and threaded holes are provided at the upper and lower ends of the jack, which are respectively threadedly connected to the jack and the push rod; the push rod passes through the kettle cover from the center hole of the guide shaft section of the kettle cover, and the lower end of the push rod is fixed to the circular seal, and the lower end of the circular seal is in contact with the detected object; the jack applies an axial load to the detected object through the push rod, and the pressure sensor monitors the axial force value in real time;

[0007] The in-casing vibration system includes a contactless vibration motor and a mounting metal plate; the vibration motor is fixed to the mounting metal plate by bolts, and the mounting metal plate is fixed to the inner wall of the sleeve by welding; the contactless vibration motor realizes contactless power supply and signal transmission through electromagnetic coupling coils arranged inside and outside the titanium alloy autoclave wall, ensuring the sealing integrity of the autoclave while supporting remote adjustment of the vibration frequency; the mechanical vibration generated by the vibration motor is transmitted to the sleeve through the mounting metal plate;

[0008] The gas boosting system includes a gas cylinder, a first air intake control valve, a boosting air pump, a three-pipe joint, a second air intake control valve and a third air intake control valve; the system working process is as follows: gas is output from the gas cylinder, regulated by the first air intake control valve, and then enters the boosting air pump for pressurization, and then is divided into two independent air paths through the three-pipe joint, among which air path a enters the interior of the kettle through the second embedded axial pipe inside the kettle body after being controlled by the second air intake control valve to achieve pressure loading, and air path b enters the interior of the casing from the center hole at the bottom of the kettle body after being regulated by the third air intake control valve and extends to the middle and upper part of the plug position, thereby forming a closed pressurized space between the inner wall of the casing, the plug and the circular seal; a drilling fluid holding chamber is formed between the bottom of the plug and the bottom of the kettle.

[0009] The electrolytic corrosion system includes: an anode electrode, a cathode electrode, a reference electrode, an electrolyte circulation device, an electrolysis workstation, and wires. The anode electrode, cathode electrode, and reference electrode are evenly distributed and installed on the kettle cover, and their working sections extend through the kettle cover to the annular area. The electrode terminals are located on the upper part of the kettle cover. The terminals of the three electrodes are connected to the electrolysis workstation via wires to achieve precise control and real-time monitoring of the electrolysis reaction.

[0010] The electrolyte circulation device comprises: a liquid storage tank, a three-way joint, a first high-pressure water pump, and a second high-pressure water pump, wherein the three-way joint, a first liquid inlet control valve, a first high-pressure water pump, a first flow control valve, a second liquid inlet control valve, a lower inlet of a first embedded axial pipe, an upper outlet of the first embedded axial pipe, an erosion area of ​​the test object inside the kettle body, a bottom liquid outlet of the kettle body, a first liquid outlet control valve, a second flow control valve, a second high-pressure water pump, a second liquid outlet control valve, and the three-way joint are connected in sequence; an interface of the liquid storage tank is connected to a third interface of the three-way joint via the liquid storage tank control valve;

[0011] The electrolyte circulation path is: three-way connector, first liquid inlet control valve, first high-pressure water pump, first flow control valve, second liquid inlet control valve, first embedded axial pipeline, erosion area of ​​the test object, bottom liquid outlet of the kettle body, first liquid outlet control valve, second flow control valve, second high-pressure water pump, second liquid outlet control valve and three-way connector.

[0012] The ultrasonic detection system in the casing includes a rubber plug, an ultrasonic sensor sounder, an ultrasonic sensor receiver, a sensor receiver mounting bracket and a drilling fluid injection system; the system is arranged in a sealed space formed by the casing, the bottom of the kettle and the circular seal, wherein the rubber plug divides the space into an upper sealed space a and a lower sealed space b; the ultrasonic sensor sounder is fixed to the lower end face of the rubber plug, and the ultrasonic sensor receiver is fixed to the lower middle part of the casing through the receiver mounting bracket. The pressure difference between the sealed space a and the sealed space b is adjusted by the gas boosting system to drive the rubber plug to move up and down, thereby changing the detection distance between the sounder and the receiver; the drilling fluid injection system consists of a liquid storage tank, a liquid inlet control valve, a centrifugal pump and a liquid outlet control valve. Driven by the centrifugal pump, the drilling fluid is injected from the liquid storage tank through the pipeline into the sealed space a, which is used to regulate the space pressure and serve as an ultrasonic wave propagation medium to realize non-destructive detection of the cement ring of oil and gas well cementing.

[0013] We also designed a real-time monitoring system for the vibration-CO2 corrosion coupling effect of the cement sheath in oil and gas wells under high temperature and high pressure environments. The technical solution includes:

[0014] Step 1: Preparation phase, including:

[0015] Step 11: Install the detection system inside the casing: Fix the non-contact vibration motor of the vibration system to the motor mounting metal plate at the lower section of the casing; simultaneously install the ultrasonic detection system, fix the ultrasonic sensor sounder at the center of the lower end surface of the rubber plug, install the rubber plug in the limiting area of ​​the upper section of the casing, and install the ultrasonic sensor receiver on the sensor receiver mounting bracket in the middle section of the casing;

[0016] Step 12: Install the sealing ring and position the components: Install the second sealing ring in the limiting groove of the casing in the kettle body, and install the third sealing ring in the limiting groove of the formation ring; then place the casing and formation ring into the corresponding groove areas respectively to ensure accurate positioning;

[0017] Step 13, cement slurry preparation and pouring: prepare cement slurry and inject it into the annulus of the casing and the rock formation until it is flush, forming a test body consisting of the casing, cement ring and rock formation ring;

[0018] Step 14: Axial loading and sealing: Start the jack and drive the push rod downward along the guide shaft section to make the circular seal closely contact with the object to be tested; install the first sealing ring in the sealing groove of the kettle cover; fasten the kettle body and the kettle cover with high-strength bolts to complete the system sealing assembly;

[0019] Step 2: Conduct monitoring, including:

[0020] Step 21: Conduct electrolytic corrosion test and ultrasonic testing;

[0021] Step 22: Perform CT scan.

[0022] During the preparation phase of step 1, the experimental conditions are set simultaneously: a preset pressure is applied to the object being tested through the jack in the axial loading system; the heating collar is simultaneously started to raise the temperature of the kettle to the set value; and the booster air pump in the gas booster system is used to increase the pressure in the kettle to the specified pressure value, completing the establishment of the experimental environment.

[0023] The vibratory curing process of the cement slurry in step 13 includes presetting the operating parameters of the non-contact vibration motor of the vibration system within the casing, starting the motor to vibrate the cement slurry, and then shutting off the motor after the vibration is complete. The cement slurry is then cured under the established temperature, pressure, and load conditions until it fully solidifies into a cement sheath.

[0024] The electrolytic corrosion test process includes:

[0025] Electrolyte injection: Open the liquid storage tank control valve, the first liquid inlet control valve, and the second liquid inlet control valve; start the first high-pressure water pump; pump the electrolyte in the liquid storage tank into the annulus through the pipeline and the first embedded axial pipeline to reach the set liquid level;

[0026] Electrolyte circulation: open the first liquid outlet control valve and the second liquid outlet control valve, close the liquid storage tank control valve; adjust the first flow control valve and the second flow control valve to control the flow rate;

[0027] Electrode connection and reaction control: The anode electrode, cathode electrode and reference electrode are connected to the electrolysis workstation via wires to achieve precise control of the electrolysis process. When CT and ultrasonic detection of cement sheath corrosion begin, the reaction is immediately terminated, which not only accelerates the corrosion of the rock sheath and shortens the cycle, but also avoids excessive electrolysis that affects data reliability.

[0028] The ultrasonic detection process includes:

[0029] Detection system positioning: The enclosed space formed by the casing, the bottom of the kettle, and the circular seal is divided into sealed space a and sealed space b by a rubber plug. A sounder is fixed to the lower end of the rubber plug, and a receiver is installed in the middle section of the casing. The pressure in space a is regulated by a gas booster system, and the pressure in space b is controlled by a drilling fluid injection system. The pressure differential is used to adjust the rubber plug position and optimize the detection spacing. The rubber plug position is verified by combining the drilling fluid injection volume and CT scanning.

[0030] Wireless signal acquisition: The detection system is activated, and the transmitter transmits ultrasonic pulses of a specific frequency to the cement sheath through the drilling fluid medium; the receiver collects the ultrasonic signals transmitted through the cement sheath in real time and sends the data to an external terminal via wireless transmission;

[0031] Real-time signal processing and analysis: The acquisition system processes the signal in real time and dynamically monitors the structural evolution of the cement sheath in a CO2 corrosion environment by analyzing characteristic parameters such as sound wave propagation velocity, signal attenuation coefficient, and spectrum changes.

[0032] The CT inspection process includes:

[0033] CT scanning control: The telescopic cylinder drives the CT mounting frame to move axially, and the motor drives the CT mounting frame to rotate through the gears, so that the CT mounting frame can achieve synchronous rotation and translation motion to form a precise spiral scanning trajectory;

[0034] Data acquisition: Start the motor to rotate the CT device at a constant speed of 0.5-2rpm, synchronously trigger the X-ray source and receiving target to scan continuously, and transmit the data to the image workstation through the data line;

[0035] Image processing: Use the FDK algorithm to reconstruct the three-dimensional image of the inspected object; analyze the changes in cement sheath porosity, corrosion depth, and crack characteristics; establish a three-dimensional corrosion model and calculate the corrosion rate.

[0036] The beneficial effects of the present invention are:

[0037] 1. By integrating axial loading, vibration excitation, electrolytic accelerated corrosion, and nondestructive testing technologies, the system achieves accurate simulation and real-time monitoring of the corrosion behavior of cement sheaths under complex working conditions. This provides an important experimental method for evaluating the long-term sealing performance of cement sheaths and optimizing cementing material formulations, and has important engineering application value for ensuring the long-term safe production of oil and gas wells.

[0038] 2. The integrated axial loading, gas pressurization, and heating devices accurately simulate the high-temperature and high-pressure environment of underground wells, significantly improving experimental reliability. The closed-loop electrolysis system precisely controls corrosion conditions, significantly shortening the experimental cycle. CT and ultrasonic waves work together to achieve multi-dimensional dynamic monitoring of the corrosion process.

[0039] 3. Use a contactless vibration system to optimize cement slurry properties while ensuring sealing.

[0040] 4. Provides key data support for cement sheath evaluation and material optimization. The system simulates vibration-corrosion coupling to realistically reproduce downhole working conditions. Its multi-parameter real-time monitoring function provides an innovative solution for cementing quality evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A three-dimensional isometric diagram of an embodiment of a system and method for real-time monitoring of vibration-CO2 corrosion coupling in a high-temperature and high-pressure environment of an oil and gas well cement sheath according to the present invention;

[0042] Figure 2 It is a schematic diagram of the overall cross-sectional structure of the kettle system;

[0043] Figure 3 It is a structural diagram of the kettle cover in the kettle system;

[0044] Figure 4 It is a three-dimensional axonometric diagram of the axial loading system;

[0045] Figure 5 It is a schematic diagram of the cross-sectional structure of the enclosed space in the casing;

[0046] Figure 6 It is the overall three-dimensional axonometric drawing of the electrolytic corrosion system;

[0047] Figure 7 This is a schematic diagram of the distribution of electrode terminals on the kettle cover;

[0048] Figure 8 Schematic diagram of the gas boosting system structure;

[0049] Figure 9 It is a schematic diagram of the structure of the ultrasonic detection system;

[0050] Figure 10 It is a structural diagram of the CT scanning detection system;

[0051] Figure 11 for Figure 10 A local magnified view of area I;

[0052] Figure 12 The ultrasonic variable density logging principle of the experimental device.

[0053] Among them, 1- kettle system, 2- axial loading system, 3- casing vibration system, 4- electrolytic corrosion system, 5- gas boosting system, 6- casing ultrasonic detection system, 7- CT detection system,

[0054] 101-titanium alloy metal reactor body, 102-reactor cover, sealing area 10201, guide shaft section 10202, 103-first sealing ring, 104-sleeve, 105-second sealing ring, 106-cement ring, 107-rock ring, 108-third sealing ring, 109-heating sleeve, 110-temperature sensor, 111-electronic pressure relief valve, 112-annulus, 113-first embedded axial pipe, 114-second embedded axial pipe,

[0055] 201-base, 202-pillar, 203-jack support plate, 204-jack, 205-pressure sensor, 206-push rod, 207-circular seal,

[0056] 301-non-contact vibration motor, 302-mounting metal plate,

[0057] 401- anode electrode, 402- cathode electrode, 403- reference electrode, 404- electrolyte circulation device, 40401- liquid storage tank, 40402- liquid storage tank control valve, 40403- three-way connector, 40404- first liquid inlet control valve, 40405- second liquid outlet control valve, 40406- first high-pressure water pump, 40407- second high-pressure water pump, 40408- ​​first flow control valve, 40409- second flow control valve, 40410- second liquid inlet control valve, 40411- first liquid outlet control valve, 40412- safety valve, 405- electrolysis workstation, 406- wire,

[0058] 501-gas cylinder, 502-first air intake control valve, 503-boosting air pump, 504-three-pipe joint, 505-second air intake control valve, 506-third air intake control valve,

[0059] 601-Rubber plug, 602-Ultrasonic sensor sounder, 603-Ultrasonic sensor receiver, 604-Sensor receiver mounting bracket, 605-Drilling fluid injection system, 60501-Liquid storage tank, 60502-Liquid inlet control valve, 60503-Centrifugal pump, 60504-Liquid outlet control valve,

[0060] 701- telescopic cylinder, 702- motor support plate, 703- CT frame rotating gear, 704- CT mounting frame, 705- X-ray generator, 706- X-ray receiving target, 707- small motor, 708- driving gear, 709- linear bearing, 710- shaft end retaining ring. DETAILED DESCRIPTION

[0061] The present invention will be further described in detail below with reference to the accompanying drawings.

[0062] like Figure 1 The embodiment of the present invention shown includes: a kettle system 1, an axial loading system 2, an in-casing vibration system 3, an electrolytic corrosion system 4, a gas pressurizing system 5, and a non-destructive testing system 6; wherein the kettle system 1 is fixed to the base 201 of the axial loading system 2, and the push rod 206 of the axial loading system 2 extends from the center of the kettle cover 102 into the kettle system 1 and presses on the object to be tested; the CT detection system 7 is installed below the jack support plate 203 of the axial loading system 2; the electrolytic corrosion system 4 is connected to the lower end inlet of the first embedded axial pipe 113 on the side wall of the kettle body 101 in the kettle system 1 to apply the experimental environment; the gas pressurizing system 5 is divided into two paths, one of which enters the kettle system 1 from the bottom, and the other is connected to the lower end inlet of the second embedded axial pipe 114; the casing 104 of the kettle system 1 is fixed in the kettle system 1, the non-destructive testing system 6 is installed in the middle of the casing 104, and the in-casing vibration system 3 is installed at the bottom of the casing 104;

[0063] During the experimental preparation stage, the casing 104 and the rock ring 107 are installed in the kettle body 101 and cement slurry is injected to form the test object. The axial load is applied by the jack 204 of the axial loading system 2. After the kettle body is sealed, CO2 gas is injected by the gas booster system 5 to establish a confining pressure environment. At the same time, the ring 109 is heated to make the system reach the set temperature. The environment at this time simulates the actual underground situation. The contactless vibration motor 301 of the in-casing vibration system 3 vibrates to optimize the cement structure during the cement slurry curing stage. The electrolytic corrosion system 4 accelerates the corrosion process through the action of circulating electrolyte and electrodes, and the corrosion evolution of the cement ring 106 is monitored in real time by the in-casing ultrasonic detection system 6 and CT detection system 7. When it is detected that the corrosion of the rock ring 107 is complete and the corrosion of the cement ring 106 is initial, the electrolytic reaction is immediately stopped. The performance degradation law of the cement stone under the vibration-corrosion coupling effect is obtained through multimodal data fusion analysis of the in-casing ultrasonic detection system 6 and CT detection system 7.

[0064] like Figure 2 and Figure 3 The kettle system 1 shown includes: a titanium alloy metal kettle body 101, a kettle cover 102, a first sealing ring 103, a sleeve 104, a second sealing ring 105, a cement ring 106, a formation ring 107, a third sealing ring 108, a heating sleeve 109, a temperature sensor 110, an electronic pressure relief valve 111 and an annulus 112, a first embedded axial pipe 113, and a second embedded axial pipe 114; the kettle body 101 and the kettle cover 102 are connected by bolts, and the first sealing ring 103 is arranged at the joint between the two to ensure sealing; the kettle cover 102 is divided into a sealing area 10201 and a guide shaft section 10202; two annular grooves are provided at the bottom of the kettle body 101, which are used to install the sleeve 104 and the formation ring 107 respectively, and the second sealing ring 105 is installed in the first annular groove to realize the sleeve 104 and the kettle body 1 01, and the third sealing ring 108 is installed in the second annular groove to achieve the sealing of the rock ring 107 and the kettle body 101; the temperature sensor 110 and the electronic pressure relief valve 111 are integrated and installed at the specified position of the kettle cover 102; the sleeve 104, the cement ring 106 and the rock ring 107 together constitute the detected object; the area between the detected object and the inner wall of the kettle body is the annulus 112, and the side wall of the kettle body 101 is integrated with two groups of first embedded axial pipes 113 and second embedded axial pipes 114 arranged from bottom to top, wherein the first embedded axial pipes 113 and the second embedded axial pipes 114 with the inlet at the bottom and the outlet at the top are used for liquid intake and air intake respectively, so as to avoid interference with the CT detection system 7 caused by bubbles generated in the electrolyte during liquid intake and air intake; the heating sleeve 109 is installed at the outer bottom of the kettle body 101.

[0065] like Figure 4The axial loading system 2 shown includes: a base 201, a pillar 202, a jack support plate 203, a jack 204, a pressure sensor 205, a push rod 206 and a circular seal 207; the base 201 is used to fix the kettle body 101, and is connected to the two pillars 202 by bolts to ensure structural stability; the top of the pillar 202 is fixedly connected to the jack support plate 203 by bolts, and the jack 204 is installed on the jack support plate 203 by bolts and provides a support reaction force; the pressure sensor 205 is set below the jack 204, Threaded holes are provided at the upper and lower ends, which form threaded connections with the jack 204 and the push rod 206 respectively; the push rod 206 passes through the kettle cover 102 from the center hole of the kettle cover guide shaft section 10202 and the lower end of the push rod 206 is fixed to the circular seal 207, and the lower end of the circular seal 207 is in contact with the test object; the jack 204 applies axial load to the test object through the push rod 206, and the pressure sensor 205 monitors and displays the axial force value in real time, and there are two O-rings 207 between the push rod and the hole in the center of the kettle cover guide shaft section 10202, thereby ensuring the airtightness of the kettle body.

[0066] like Figure 5 The vibration system 3 in the casing shown includes: a contactless vibration motor 301 and a mounting metal plate 302; the vibration motor 301 is fixed to the mounting metal plate 302 by bolts, and the mounting metal plate 302 is fixed to the inner wall of the sleeve 104 by welding; the contactless vibration motor 301 realizes non-contact power supply and signal transmission through electromagnetic coupling coils arranged inside and outside the titanium alloy autoclave wall, while ensuring the sealing integrity of the autoclave and supporting remote adjustment of the vibration frequency; the mechanical vibration generated by the vibration motor 301 is transmitted to the sleeve 104 through the mounting metal plate 302, promoting uniform distribution of particles during cement slurry pouring, thereby significantly improving the density and structural uniformity of the formed cement ring 106.

[0067] like Figure 6 and Figure 7 The electrolytic corrosion system 4 shown includes: an anode electrode 401, a cathode electrode 402, a reference electrode 403, an electrolyte circulation device 404, an electrolysis workstation 405 and a wire 406; the three electrodes are evenly distributed at equal angles and installed on the kettle cover 102, and their working sections extend through the kettle cover 102 to the annulus 112 area. The electrode terminals are located on the upper part of the kettle cover 102; the electrolyte circulation device 404 includes: a liquid storage tank 40401, a liquid storage tank control valve 40402, a three-way connector 40403, a first liquid inlet control valve 40404, a second liquid outlet control valve 40405, a first high-pressure water pump 40406, a second high-pressure water pump 40407, a first flow control valve 40408, a second flow control valve 40409, a second liquid inlet control valve 40410, a second liquid outlet control valve 40411 and a safety valve 40412;

[0068] The three-way connector 40403, the first liquid inlet control valve 40404, the first high-pressure water pump 40406, the first flow control valve 40408, the second liquid inlet control valve 40410, the lower inlet of the first embedded axial pipe 113 inside the kettle body 101, the upper outlet of the first embedded axial pipe 113, the erosion area of ​​the test object inside the kettle body 101 (the annulus 112 area filled with electrolyte), the bottom liquid outlet of the kettle body 101 (not shown in the figure, located in the kettle body 101 below the annulus 112), the first liquid outlet control valve 40411, the second flow control valve 40409, the second high-pressure water pump 40407, the second liquid outlet control valve 40405 and the three-way connector 40403 are connected in sequence to form an electrolyte circulation;

[0069] The interface of the liquid storage tank 40401 is connected to the third interface of the liquid storage tank control valve 40402 and the three-way connector 40403, thereby connecting to the electrolyte circulation.

[0070] The electrolyte injection path is: liquid storage tank 40401 → T-connector 40403 → liquid storage tank control valve 40402 → first liquid inlet control valve 40404 → first high-pressure water pump 40406 → first flow control valve 40408 → second liquid inlet control valve 40410 → first embedded axial pipe 113 inside the kettle body 101 → inside the kettle body 101 → erosion area of ​​the test object. At this time, the second liquid outlet control valve 40405 is closed.

[0071] The electrolyte circulation path is: three-way connector 40403 → first liquid inlet control valve 40404 → first high-pressure water pump 40406 → first flow control valve 40408 → second liquid inlet control valve 40410 → first embedded axial pipe 113 inside the kettle body 101 → inside the kettle body 101 → corrosion area of ​​the test object → bottom liquid outlet of the kettle body 101 (not shown in the figure) → first liquid outlet control valve 40411 → second flow control valve 40409 → second high-pressure water pump 40407 → second liquid outlet control valve Valve 40405 → T-joint 40403, forming a closed-loop circulation system. At this time, the liquid storage tank control valve 40402 is closed. Then, the circulation parameters are set, the required pumps (first liquid outlet control valve 40411 and / or first high-pressure water pump 40406) are started, and the flow control valve is adjusted so that the electrolyte forms a closed circulation loop between the kettle body 101 and the liquid storage tank 404 at the set flow rate. The terminal posts of the three electrodes are connected to the electrolysis workstation 405 via wires 406 to achieve precise control and real-time monitoring of the electrolysis reaction.

[0072] The electrolyte discharge path is: the erosion area of ​​the test object → the bottom liquid outlet of the kettle body 101 (not shown in the figure) → the first liquid outlet control valve 40411 → the second flow control valve 40409 → the second high-pressure water pump 40407 → the second liquid outlet control valve 40405 → the three-way connector 40403 → the liquid storage tank control valve 40402 → the liquid storage tank 40401. At this time, the first liquid inlet control valve 40404 is closed.

[0073] like Figure 8 The gas boosting system 5 shown includes a gas cylinder 501, a first air intake control valve 502, a boosting air pump 503, a three-pipe joint 504, a second air intake control valve 505, and a third air intake control valve 506. The system operation is as follows: the gas is output from the gas cylinder 501, regulated by the first air intake control valve 502, and then enters the boosting air pump 503 for pressurization, and then is divided into two independent air paths through the three-pipe joint 504, wherein the air path a is controlled by the second air intake control valve 505 and then passes through the second embedded air path inside the kettle body 101. The inlet axial pipe 114 enters the interior of the kettle body to realize pressure loading, and the air path b enters the interior of the casing 104 from the central hole at the bottom of the kettle body after being regulated by the third air inlet control valve 506 and extends to the position of the plug 601 in the upper middle part, thereby forming a closed pressurized space between the inner wall of the casing 104, the plug 701 and the circular seal 207; the drilling fluid holding chamber is formed between the bottom of the plug 601 and the bottom of the kettle. By accurately controlling the pressure difference between the two closed spaces, precise displacement control of the plug 601 can be achieved.

[0074] In this embodiment, the gas cylinder 501 is filled with CO2.

[0075] like Figure 9 The ultrasonic detection system 6 in the casing shown includes a rubber plug 601, an ultrasonic sensor sounder 602, an ultrasonic sensor receiver 603, a sensor receiver mounting bracket 604 and a drilling fluid injection system 605; the system is arranged in a sealed space formed by the casing 104, the bottom of the kettle 101 and the circular seal 207, wherein the rubber plug 601 divides the space into an upper sealed space a and a lower sealed space b; the ultrasonic sensor sounder 602 is fixed to the lower end surface of the rubber plug 601, and the ultrasonic sensor receiver 603 is fixed to the casing 104 through the receiver mounting bracket 604. In the lower middle part of 04, the pressure difference between the sealed space a and the sealed space b is adjusted by the gas booster system 5 to drive the rubber plug 601 to move up and down, thereby changing the detection distance between the sounder 602 and the receiver 603; the drilling fluid injection system 605 consists of a liquid storage tank 60501, a liquid inlet control valve 60502, a centrifugal pump 60503 and a liquid outlet control valve 60504. Driven by the centrifugal pump 60503, the drilling fluid is injected from the liquid storage tank 60501 through the pipeline into the sealed space a, which is used to regulate the space pressure and serve as an ultrasonic wave propagation medium to realize non-destructive testing of the cement ring of oil and gas wells.

[0076] like Figure 10 and Figure 11 The CT detection system 7 shown can realize spiral scanning of the object to be detected, and includes: a telescopic cylinder 701, a motor support plate 702, a CT frame rotating gear 703, a CT mounting frame 704, an X-ray generator 705, an X-ray receiving target 706, a small motor 707, a driving gear 708, a linear bearing 709 and a shaft end retaining ring 710. The piston rod of the telescopic cylinder 701 is threadedly connected to the motor support plate 702, and the linear bearing 709 is sleeved on the outside of the kettle cover guide shaft section 10202. The telescopic drive of the cylinder piston rod drives the entire CT device to slide along the kettle cover guide shaft section 10202. The linear bearing 709 is connected to the CT mounting frame 704 through a slewing bearing. The CT mounting frame 704 is fixed A CT frame rotating gear 703 is fixedly installed, and the axes of the kettle cover guide shaft section 10202, the CT frame rotating gear 703, the slewing bearing and the linear bearing 709 are coaxial; the motor support plate 702 and the linear bearing 709 are fixed; the small motor 707 is fixed on the motor support plate 702, and its output shaft is fixed to the driving gear 708, and the driving gear 708 is engaged with the CT frame rotating gear 703 for transmission, and the CT mounting frame 704 is driven to rotate around the center of the kettle body 101 by the rotation of the motor; the X-ray generator 705 and the X-ray receiving target 706 are symmetrically installed on both sides of the bottom of the CT mounting frame 704, and spiral CT scanning of the object to be detected in the center of the kettle body 101 is achieved through coordinated rotational motion and axial movement.

[0077] The test method of this embodiment includes:

[0078] Step 1: Preparation phase, including:

[0079] Step 11, installation of the detection system inside the casing: fix the contactless vibration motor 301 of the vibration system 3 on the motor mounting metal plate 302 at the lower section of the casing 104; at the same time, install the ultrasonic detection system 6, fix the ultrasonic sensor sounder 602 at the center position of the lower end surface of the plug 601, the plug 601 is installed in the limiting area of ​​the upper section of the casing 104, and the ultrasonic sensor receiver 603 is installed on the sensor receiver mounting bracket 604 in the middle section of the casing 104.

[0080] Step 12, sealing ring installation and component positioning: install the second sealing ring 105 in the limiting groove of the sleeve 104 in the kettle body 101, and install the third sealing ring 108 in the limiting groove of the rock ring 107; then place the sleeve 104 and the rock ring 107 into the corresponding groove areas respectively to ensure accurate positioning.

[0081] Step 13, cement slurry preparation and pouring: Cement slurry is prepared according to GB / T 19139-2012 and injected into the annulus of the casing 104 and the rock ring 107 until they are flush, forming a test body consisting of the casing 104, cement ring 106 and rock ring 107.

[0082] Step 14: Axial loading and sealing: Start the jack 204 and drive the push rod 206 downward along the guide shaft section 10202 to make the circular seal 207 in close contact with the object to be detected; install the first sealing ring 103 in the sealing groove of the kettle cover 102; fasten the kettle body 101 and the kettle cover 102 with high-strength bolts to complete the system sealing assembly;

[0083] Step 2: Conduct monitoring, including:

[0084] Step 21: Conduct electrolytic corrosion test and ultrasonic testing;

[0085] Step 22: Perform CT scan.

[0086] During the preparation phase of step 1, the experimental conditions are set simultaneously: a preset pressure is applied to the object to be tested through the jack 204 in the axial loading system 2; the heating collar 109 is simultaneously started to raise the temperature of the kettle to the set value; and the booster air pump in the gas booster system 5 is used to increase the pressure in the kettle to the specified pressure value, thereby completing the establishment of the experimental environment.

[0087] The vibratory curing process for the cement slurry in step 13 includes presetting the operating parameters of the contactless vibration motor 301 of the in-casing vibration system 3, starting the motor to vibrate the cement slurry, and then shutting off the motor after the vibration is complete. The cement slurry is then cured under the established temperature, pressure, and load conditions until it completely solidifies into a cement ring.

[0088] The electrolytic corrosion test process includes:

[0089] Step 211, electrolyte injection: Open the liquid storage tank control valve 40402, the first liquid inlet control valve 40404, and the second liquid inlet control valve 40410; start the first high-pressure water pump 40406; pump the electrolyte in the liquid storage tank 40401 into the annulus 112 through the pipeline and the first embedded axial pipeline 113 to reach the set liquid level;

[0090] Step 212, electrolyte circulation: open the first liquid outlet control valve 40405 and the second liquid outlet control valve 40411, and close the liquid storage tank control valve; adjust the first flow control valve 40408 and the second flow control valve 40409 to control the flow rate to 0.1-1.0 m / s; regularly replace the electrolyte in the liquid storage tank 40401 to maintain a constant concentration;

[0091] Step 213, electrode connection and reaction control: The anode electrode 401, cathode electrode 402, and reference electrode 403 are connected to the electrolysis workstation 405 via wire 406 to achieve precise control of the electrolysis process. When CT and ultrasonic waves detect that the cement sheath has begun to corrode, the reaction is immediately terminated, which not only accelerates the corrosion of the rock sheath 107 and shortens the corrosion cycle, but also prevents excessive electrolysis from affecting data reliability.

[0092] When the electrolyte needs to be drained during or after the test, the second high-pressure water pump 40407 is started, and the electrolyte in the annulus 112 flows back to the liquid storage tank 40401;

[0093] The ultrasonic testing process includes:

[0094] Step 231, positioning the detection system: The enclosed space formed by the casing 104, the bottom of the kettle 101, and the circular seal 207 is divided into sealed space a and sealed space b by the rubber plug 601; a sounder 602 is fixed to the lower end of the rubber plug 601, and a receiver 603 is installed in the middle section of the casing 104; the pressure in space a is regulated by the gas booster system 5, and the pressure in space b is controlled by the drilling fluid injection system 605. The position of the rubber plug 601 is adjusted by the pressure differential to optimize the detection spacing; the position of the rubber plug 601 is verified by combining the drilling fluid injection volume and CT scanning;

[0095] Step 232, wireless signal acquisition: The detection system is activated, and the transmitting end 602 transmits ultrasonic pulses of a specific frequency to the cement sheath 106 through the drilling fluid medium; the receiving end 603 collects the ultrasonic signals transmitted through the cement sheath 106 in real time and sends the data to an external terminal via wireless transmission;

[0096] Step 233, real-time signal processing and analysis: The acquisition system processes the signal in real time and dynamically monitors the structural evolution of the cement sheath 106 in the CO2 corrosion environment by analyzing characteristic parameters such as the acoustic wave propagation velocity, signal attenuation coefficient, and spectrum change.

[0097] The CT inspection process includes:

[0098] Step 221, CT scanning control: the telescopic cylinder 701 drives the CT mounting frame 704 to move axially, and the motor 707 drives the CT frame rotation gear 703 to rotate through the gear 708, so that the CT mounting frame 704 can achieve synchronous rotation and translation motion, forming a precise spiral scanning trajectory;

[0099] Step 222, data acquisition: start the motor to rotate the CT device at a constant speed of 0.5-2 rpm, synchronously trigger the X-ray source 705 and the receiving target 706 to scan continuously, collect one frame of image every 0.5°, a total of 720 images, and transmit them to the image workstation 711 via the data line;

[0100] Step 223, image processing: reconstructing a three-dimensional image of the object under test using the FDK algorithm; analyzing the porosity change, corrosion depth, and crack characteristics of the cement sheath 106; establishing a three-dimensional corrosion model and calculating the corrosion rate.

Claims

1. A real-time monitoring system for the vibration-CO2 corrosion coupling effect of the cement sheath of an oil and gas well under high temperature and high pressure environment, characterized in that: include: A kettle system (1), an axial loading system (2), a casing vibration system (3), an electrolytic corrosion system (4), a gas pressurization system (5) and a non-destructive testing system (6); wherein the kettle system (1) is fixed to a base (201) of the axial loading system (2); a push rod (206) of the axial loading system (2) extends from the center of the kettle cover (102) into the kettle system (1) and presses on the object to be tested; a CT detection system (7) is installed below the jack support plate (203) of the axial loading system (2); The system (4) is connected to the lower end of the first embedded axial pipe (113) on the side wall of the kettle body (101) in the kettle system (1) to apply the experimental environment; the gas boosting system (5) is divided into two paths, one of which enters the kettle system (1) from the bottom, and the other is connected to the lower end of the second embedded axial pipe (114); the casing (104) of the kettle system (1) is fixed in the kettle system (1), the non-destructive testing system (6) is installed in the middle of the casing (104), and the casing vibration system (3) is installed in the lower part of the casing (104); The CT detection system (7) comprises a telescopic cylinder (701), a motor support plate (702), a CT frame rotating gear (703), a CT mounting frame (704), an X-ray generator (705), an X-ray receiving target (706), a small motor (707), a driving gear (708) and a linear bearing (709); wherein the piston rod of the telescopic cylinder (701) is threadedly connected to the motor support plate (702), and the linear bearing (709) is sleeved on the outside of the kettle cover guide shaft section (10202), thereby driving the entire CT device to slide along the kettle cover guide shaft section (10202) through the telescopic drive of the cylinder piston rod; the linear bearing (709) is connected to the CT mounting frame (704) through a slewing bearing, and the CT mounting frame (704) is fixed A CT frame rotating gear (703) is installed, and the axes of the CT frame rotating gear (703), the slewing bearing and the linear bearing (709) are coaxial; the motor support plate (702) and the linear bearing (709) are fixed; a small motor (707) is fixed on the motor support plate (702), and its output shaft is fixed to the driving gear (708), and the driving gear (708) is engaged with the CT frame rotating gear (703) for transmission, and the CT mounting frame (704) is driven to rotate around the center of the kettle body (101) by the rotation of the motor; an X-ray generator (705) and an X-ray receiving target (706) are symmetrically installed on both sides of the bottom of the CT mounting frame (704), and spiral CT scanning of the object to be detected in the center of the kettle body (101) is achieved through coordinated rotational motion and axial movement.

2. The real-time monitoring system for vibration-CO2 corrosion coupling of oil and gas well cement sheath under high temperature and high pressure environment according to claim 1 is characterized in that: The kettle system (1) comprises: a kettle body (101), a kettle cover (102), a first sealing ring (103), a sleeve (104), a second sealing ring (105), a cement ring (106), a rock ring (107), a third sealing ring (108), a heating sleeve (109), a temperature sensor (110), an electronic pressure relief valve (111) and an annulus (112), a first embedded axial pipe (113), and a second embedded axial pipe (114); the kettle body (101) and the kettle cover (102) are connected by bolts, and the first sealing ring (103) is arranged at the joint between the two to ensure sealing; the kettle cover (102) is divided into a sealing area (10201) and a guide shaft section (10202); two annular grooves are provided at the bottom of the kettle body (101), which are respectively used for installing the sleeve (104) and the rock ring (107) for limiting fixation, and the second sealing ring (105) is installed The sleeve (104) and the kettle body (101) are sealed in the first annular groove, and the third sealing ring (108) is installed in the second annular groove to achieve the sealing of the rock ring (107) and the kettle body (101); the temperature sensor (110) and the electronic pressure relief valve (111) are integrated and installed at a specified position of the kettle cover (102); the sleeve (104), the cement ring (106) and the rock ring (107) together constitute the detected object; the area between the detected object and the inner wall of the kettle body is an annulus (112), and the side wall of the kettle body (101) is integrated with two groups of first embedded axial pipes (113) and second embedded axial pipes (114) arranged from bottom to top, wherein the first embedded axial pipe (113) and the second embedded axial pipe (114) with an inlet at the bottom and an outlet at the top are used for liquid intake and gas intake respectively; the heating sleeve ring (109) is installed at the outer bottom of the kettle body (101).

3. The real-time monitoring system for vibration-CO2 corrosion coupling of cement sheath in oil and gas wells under high temperature and high pressure environment according to claim 2 is characterized in that: The axial loading system (2) comprises a base (201), a pillar (202), a jack support plate (203), a jack (204), a pressure sensor (205), a push rod (206) and a circular seal (207); the base (201) is used to fix the kettle body (101), and is connected to the two pillars (202) by bolts to ensure structural stability; the top of the pillar (202) is fixedly connected to the jack support plate (203) by bolts, and the jack (204) is installed on the jack support plate (203) by bolts and is provided by the jack support plate (203). The pressure sensor 205 is provided below the jack (204), and threaded holes are provided at the upper and lower ends thereof, respectively forming threaded connections with the jack (204) and the push rod 206; the push rod (206) passes through the center hole of the kettle cover guide shaft section (10202) and the lower end of the push rod (206) is fixed to the circular seal (207), and the lower end of the circular seal (207) contacts the detected object; the jack (204) applies an axial load to the detected object through the push rod (206), and the pressure sensor (205) monitors the axial force value in real time; The in-casing vibration system (3) comprises a contactless vibration motor (301) and a mounting metal plate (302); the vibration motor (301) is fixed to the mounting metal plate (302) by bolts, and the mounting metal plate (302) is fixedly connected to the inner wall of the sleeve (104) by welding; the contactless vibration motor (301) realizes contactless power supply and signal transmission through electromagnetic coupling coils arranged inside and outside the titanium alloy autoclave wall, and supports remote adjustment of the vibration frequency while ensuring the sealing integrity of the autoclave; the mechanical vibration generated by the vibration motor (301) is transmitted to the sleeve (104) through the mounting metal plate (302); The gas pressurizing system (5) comprises a gas cylinder (501), a first air intake control valve (502), a pressurizing air pump (503), a three-pipe joint (504), a second air intake control valve (505) and a third air intake control valve (506); the system operation is as follows: gas is output from the gas cylinder (501), regulated by the first air intake control valve (502), enters the pressurizing air pump (503) for pressurization, and then is divided into two independent air paths through the three-pipe joint (504), wherein air path a is connected to the second air intake control valve (505) and the third air intake control valve (506). 05) is controlled by the second embedded axial pipe (114) inside the kettle body (101) to enter the kettle body to realize pressure loading, and the air path b enters the casing (104) from the central hole at the bottom of the kettle body after being adjusted by the third air inlet control valve (506) and extends to the position of the rubber plug (601) in the middle and upper part, thereby forming a closed pressurized space between the inner wall of the casing (104), the rubber plug (701) and the circular sealing member (207); and a drilling fluid holding chamber is formed between the bottom of the rubber plug (601) and the bottom of the kettle.

4. The real-time monitoring system for vibration-CO2 corrosion coupling of oil and gas well cement sheath under high temperature and high pressure environment according to claim 2 is characterized in that: The electrolytic corrosion system (4) comprises: an anode electrode (401), a cathode electrode (402), a reference electrode (403), an electrolyte circulation device (404), an electrolysis workstation (405) and a wire (406); the anode electrode (401), the cathode electrode (402) and the reference electrode (403) are evenly distributed and installed on the kettle cover (102), and their working sections extend through the kettle cover (102) to the annulus (112) area, and the electrode terminals are located on the upper part of the kettle cover (102); the terminals of the three electrodes are connected to the electrolysis workstation (405) through the wire (406), so as to realize precise control and real-time monitoring of the electrolysis reaction; The electrolyte circulation device (404) comprises: a liquid storage tank (40401), a three-way connector (40403), a first high-pressure water pump (40406) and a second high-pressure water pump (40407), wherein the three-way connector (40403), the first liquid inlet control valve (40404), the first high-pressure water pump (40406), the first flow control valve (40408), the second liquid inlet control valve (40410), the lower inlet of the first embedded axial pipe (113), the first embedded axial pipe (114), the lower inlet of the first embedded axial pipe (115), the lower inlet of the first embedded axial pipe (116), the lower inlet of the first embedded axial pipe (117), the lower inlet of the first embedded axial pipe (118), the lower inlet of the first embedded axial pipe (119), the lower inlet of the first embedded axial pipe (111), the lower inlet of the first embedded axial pipe (119), the lower inlet of the first embedded axial pipe (119) and the lower inlet of the second embedded axial pipe (119) are connected. The upper outlet of the pipeline (113), the erosion area of ​​the test object inside the kettle body (101), the bottom liquid outlet of the kettle body (101), the first liquid outlet control valve (40411), the second flow control valve (40409), the second high-pressure water pump (40407), the second liquid outlet control valve (40405) and the three-way joint (40403) are connected in sequence; the interface of the liquid storage tank (40401) is connected via the liquid storage tank control valve (40402) and the third interface of the three-way joint (40403); The electrolyte circulation path is: a three-way connector (40403), a first liquid inlet control valve (40404), a first high-pressure water pump (40406), a first flow control valve (40408), a second liquid inlet control valve (40410), a first embedded axial pipe (113), an erosion area of ​​the test object, a bottom liquid outlet of the kettle body (101), a first liquid outlet control valve (40411), a second flow control valve (40409), a second high-pressure water pump (40407), a second liquid outlet control valve (40405) and a three-way connector (40403).

5. The real-time monitoring system for vibration-CO2 corrosion coupling of cement sheath in oil and gas wells under high temperature and high pressure environment according to claim 2 is characterized in that: The ultrasonic detection system (6) in the casing comprises a rubber plug (601), an ultrasonic sensor sounder (602), an ultrasonic sensor receiver (603), a sensor receiver mounting frame (604) and a drilling fluid injection system (605); the system is arranged in a sealed space formed by the casing (104), the bottom of the kettle (101) and the circular sealing member (207), wherein the rubber plug (601) divides the space into an upper sealed space a and a lower sealed space b; the ultrasonic sensor sounder (602) is fixed to the lower end surface of the rubber plug (601), and the ultrasonic sensor receiver (603) is fixed to the casing via the receiver mounting frame (604). In the lower part of (104), the pressure difference between the sealed space a and the sealed space b is adjusted by the gas boosting system (5) to drive the rubber plug (601) to move up and down, thereby changing the detection distance between the sounder (602) and the receiver (603); the drilling fluid injection system (605) is composed of a liquid storage tank (60501), a liquid inlet control valve (60502), a centrifugal pump (60503) and a liquid outlet control valve (60504). The drilling fluid is driven by the centrifugal pump (60503) and injected into the sealed space a from the liquid storage tank (60501) through the pipeline, which is used to regulate the space pressure and serve as an ultrasonic wave propagation medium to realize non-destructive testing of the cement ring of oil and gas well cementing.

6. A monitoring method for a real-time monitoring system for vibration-CO2 corrosion coupling under high temperature and high pressure environment of an oil and gas well cement sheath according to claim 1, characterized in that: include: Step 1: Preparation phase, including: Step 11: Install the detection system inside the casing: Fix the non-contact vibration motor of the vibration system to the motor mounting metal plate at the lower section of the casing; simultaneously install the ultrasonic detection system, fix the ultrasonic sensor sounder at the center of the lower end surface of the rubber plug, install the rubber plug in the limiting area of ​​the upper section of the casing, and install the ultrasonic sensor receiver on the sensor receiver mounting bracket in the middle section of the casing; Step 12: Install the sealing ring and position the components: Install the second sealing ring in the limiting groove of the casing in the kettle body, and install the third sealing ring in the limiting groove of the formation ring; then place the casing and formation ring into the corresponding groove areas respectively to ensure accurate positioning; Step 13, cement slurry preparation and pouring: prepare cement slurry and inject it into the annulus of the casing and the rock formation until it is flush, forming a test body consisting of the casing, cement ring and rock formation ring; Step 14: Axial loading and sealing: Start the jack and drive the push rod downward along the guide shaft section to make the circular seal closely contact with the object to be tested; install the first sealing ring in the sealing groove of the kettle cover; fasten the kettle body and the kettle cover with high-strength bolts to complete the system sealing assembly; Step 2: Conduct monitoring, including: Step 21: Conduct electrolytic corrosion test and ultrasonic testing; Step 22: Perform CT scan.

7. The method for real-time monitoring of vibration-CO2 corrosion coupling of cement sheath in oil and gas wells under high temperature and high pressure environment according to claim 6, characterized in that: During the preparation phase of step 1, the experimental conditions are set simultaneously: a preset pressure is applied to the object being tested through the jack in the axial loading system; the heating collar is simultaneously started to raise the temperature of the kettle to the set value; and the booster air pump in the gas booster system is used to increase the pressure in the kettle to the specified pressure value, completing the establishment of the experimental environment. The vibratory curing process of the cement slurry in step 13 includes presetting the operating parameters of the non-contact vibration motor of the vibration system within the casing, starting the motor to vibrate the cement slurry, and then shutting off the motor after the vibration is complete. The cement slurry is then cured under the established temperature, pressure, and load conditions until it fully solidifies into a cement sheath.

8. The method for real-time monitoring of vibration-CO2 corrosion coupling of cement sheath in oil and gas wells under high temperature and high pressure environment according to claim 6 is characterized in that: The electrolytic corrosion test process includes: Electrolyte injection: Open the liquid storage tank control valve, the first liquid inlet control valve, and the second liquid inlet control valve; start the first high-pressure water pump; pump the electrolyte in the liquid storage tank into the annulus through the pipeline and the first embedded axial pipeline to reach the set liquid level; Electrolyte circulation: open the first liquid outlet control valve and the second liquid outlet control valve, close the liquid storage tank control valve; adjust the first flow control valve and the second flow control valve to control the flow rate; Electrode connection and reaction control: The anode electrode, cathode electrode and reference electrode are connected to the electrolysis workstation via wires to achieve precise control of the electrolysis process. When CT and ultrasonic detection of cement sheath corrosion begin, the reaction is immediately terminated, which not only accelerates the corrosion of the rock sheath and shortens the cycle, but also avoids excessive electrolysis that affects data reliability.

9. The method for real-time monitoring of vibration-CO2 corrosion coupling of cement sheath in oil and gas wells under high temperature and high pressure environment according to claim 6, characterized in that: The ultrasonic detection process includes: Detection system positioning: The enclosed space formed by the casing, the bottom of the kettle, and the circular seal is divided into sealed space a and sealed space b by a rubber plug. A sounder is fixed to the lower end of the rubber plug, and a receiver is installed in the middle section of the casing. The pressure in space a is regulated by a gas booster system, and the pressure in space b is controlled by a drilling fluid injection system. The pressure differential is used to adjust the rubber plug position and optimize the detection spacing. The rubber plug position is verified by combining the drilling fluid injection volume and CT scanning. Wireless signal acquisition: The detection system is activated, and the transmitter transmits ultrasonic pulses of a specific frequency to the cement sheath through the drilling fluid medium; the receiver collects the ultrasonic signals transmitted through the cement sheath in real time and sends the data to an external terminal via wireless transmission; Real-time signal processing and analysis: The acquisition system processes the signal in real time and dynamically monitors the structural evolution of the cement sheath in a CO2 corrosion environment by analyzing characteristic parameters such as sound wave propagation velocity, signal attenuation coefficient, and spectrum changes.

10. The real-time monitoring system for vibration-CO2 corrosion coupling of cement sheath in oil and gas wells under high temperature and high pressure environment according to claim 6, characterized in that: The CT inspection process includes: CT scanning control: The telescopic cylinder drives the CT mounting frame to move axially, and the motor drives the CT mounting frame to rotate through the gears, so that the CT mounting frame can achieve synchronous rotation and translation motion to form a precise spiral scanning trajectory; Data acquisition: Start the motor to rotate the CT device at a constant speed of 0.5-2rpm, synchronously trigger the X-ray source and receiving target to scan continuously, and transmit the data to the image workstation through the data line; Image processing: Use the FDK algorithm to reconstruct the three-dimensional image of the inspected object; analyze the changes in cement sheath porosity, corrosion depth, and crack characteristics; establish a three-dimensional corrosion model and calculate the corrosion rate.

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