High temperature and high pressure wellbore multiphase flow visualization device and method based on MIT imaging

Abstract

The present application relates to the field of oil and gas drilling development, in particular to a kind of high temperature and high pressure wellbore multiphase flow visualization device and method based on MIT imaging.The technical scheme is: including temperature and pressure monitoring unit, data processing and three-dimensional imaging unit, also including wellbore simulation unit and MIT magnetic induction imaging unit, MIT magnetic induction imaging unit is installed on wellbore simulation unit;Silicon carbide wellbore is filled with three-phase experimental fluid, for adapting the simulation needs of different well diameters, and silicon carbide wellbore is installed in the center of first center variable-diameter mechanism, second center variable-diameter mechanism and third center variable-diameter mechanism;Composite heat insulation layer is arranged outside silicon carbide wellbore, and the beneficial effect is: the present application can adapt to high temperature and high pressure working condition, magnetic signal has strong anti-interference ability, the monitoring of three-phase experimental fluid is realized by the combination of the rapid adjustment of center variable-diameter mechanism and magnetic induction fault imaging technology, and it has high imaging resolution, which is of great significance to promote the progress of deep oil and gas drilling development technology.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling and development, and in particular to a high-temperature and high-pressure wellbore multiphase flow visualization device and method based on MIT imaging. Background Technology

[0002] As oil and gas exploration and development moves towards deeper and ultra-deep formations, wellbore conditions are becoming increasingly complex. Temperatures exceeding 200°C and pressures exceeding 150 MPa are becoming the norm, and multiphase flows, including gas, oil, water, and drilling fluid solid particles, commonly coexist within the wellbore. The transport patterns of these multiphase flows directly impact well control risk management, drilling efficiency, and oil production capacity; therefore, accurate monitoring and visual analysis are crucial.

[0003] Existing wellbore multiphase flow monitoring technologies have many limitations: traditional visualization simulation devices mostly use transparent plexiglass wellbores, which cannot withstand high temperature and high pressure conditions, thus limiting their applicability; contact detection methods (such as probe-type flowmeters) are easily eroded and worn by fluids and can interfere with the flow field morphology; conventional imaging technologies (such as ultrasonic and X-ray imaging) are difficult to achieve three-dimensional real-time visualization of multiphase flow and have low accuracy in component identification.

[0004] Kang Xiaofeng, Men Shouqiang, and Zhou Jun published "Research Progress in Magnetic Induction Tomography" in the *Journal of Shandong Agricultural University* (Natural Science Edition), 2018, 49(1). Magnetic induction tomography (MIT) is an imaging technique that utilizes the eddy current effect to image the electromagnetic properties of objects. It is also known as electromagnetic induction tomography, electromagnetic tomography, eddy current imaging, and eddy current detection. This method is used for non-destructive testing in engineering construction and geophysics, and is also used to generate three-dimensional images of passive electrical properties (PEP). It has applications in medical brain imaging, cryotherapy monitoring, metal flow visualization technology, and metal processing technology. Therefore, although MIT magnetic induction tomography has the advantages of being non-contact, radiation-free, and having a fast response speed, there is currently no simulation of a high-temperature, high-pressure wellbore multiphase flow visualization device based on this technology, which cannot meet the needs of deep oil and gas drilling development for multiphase flow monitoring.

[0005] Therefore, we have invented a visualization device and method for high-temperature and high-pressure wellbore multiphase flow based on MIT imaging. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned deficiencies in existing technologies by providing a visualization device and method for high-temperature and high-pressure wellbore multiphase flow based on MIT imaging. This device is adaptable to high-temperature and high-pressure operating conditions, has strong anti-interference capabilities for magnetic signals, and achieves monitoring of three-phase experimental fluids through rapid adjustment of the central diameter mechanism combined with magnetic induction tomography technology. It has high imaging resolution and is of great significance for promoting the advancement of deep oil and gas drilling and development technology.

[0007] The technical solution of the high temperature and high pressure wellbore multiphase flow visualization device based on MIT imaging mentioned in this invention is as follows: it includes a temperature and pressure monitoring unit, a data processing and three-dimensional imaging unit, a wellbore simulation unit and an MIT magnetic induction imaging unit, with the MIT magnetic induction imaging unit installed on the wellbore simulation unit.

[0008] The wellbore simulation unit includes an upper cover, a silicon carbide wellbore, a rotating connecting rod, a base, an upper connecting rod, a lower connecting rod, a first center diameter changing mechanism, a second center diameter changing mechanism, and a third center diameter changing mechanism. The silicon carbide wellbore, the first center diameter changing mechanism, the second center diameter changing mechanism, and the third center diameter changing mechanism are installed between the upper cover and the base. The silicon carbide wellbore is filled with a three-phase experimental fluid to adapt to simulation requirements of different well diameters, and the silicon carbide wellbore is mounted on the first center diameter changing mechanism, the second center diameter changing mechanism, and the third center diameter changing mechanism. The center of the diameter-changing mechanism; a composite heat insulation layer is installed on the outside of the silicon carbide well barrel, and the cavity between the silicon carbide well barrel and the composite heat insulation layer and the inner cavity of the high-temperature magnetic shield are respectively filled with silica aerogel; an annular rotating track is set on the upper cover, the upper end of the rotating connecting rod passes through the rotating track, and the lower end of the rotating connecting rod is connected to the upper surface of the first central diameter-changing mechanism; the lower end of the first central diameter-changing mechanism is connected to the second central diameter-changing mechanism through the upper connecting rod, and the lower end of the second central diameter-changing mechanism is connected to the third central diameter-changing mechanism through the lower connecting rod.

[0009] Preferably, the aforementioned first center diameter changing mechanism includes a main frame, an arc-shaped movable body, a pinion, an alumina ceramic coil skeleton, and a center gear. A silicon carbide well casing and a composite heat insulation layer are installed at the center of the main frame. A center gear is installed on the upper side of the main frame, with the outer side of the center gear meshing with the pinion. The rotation of the pinion drives the rotation of the center gear. Multiple involute arc-shaped slots are provided at the center of the center gear. The upper ends of multiple upper connecting rods pass through these involute arc-shaped slots and are fixedly connected to the ends of the alumina ceramic coil skeleton. The lower ends of the upper connecting rods are connected to the involute arc-shaped slots of the second center diameter changing mechanism. The outer end of the alumina ceramic coil skeleton is connected to the arc-shaped movable body, and the inner end of the alumina ceramic coil skeleton is inserted into the inner cavity of the main frame. When the center gear rotates, the upper connecting rods move along the involute arc-shaped slots, causing the alumina ceramic coil skeleton to extend outwards or retract inwards, thus realizing the extension and retraction of the arc-shaped movable body, thereby achieving the diameter changing of the first center diameter changing mechanism.

[0010] Preferably, the aforementioned involute groove is provided in five sets, which extend from the center of the central gear to the periphery. Each set of involute grooves is provided with an upper connecting rod. The five upper connecting rods expand or contract along the involute grooves, while simultaneously driving the lower connecting rods to expand or contract along the involute grooves of the second and third central diameter changing mechanisms.

[0011] Preferably, the aforementioned MIT magnetic induction imaging unit includes a high-frequency low-parasitic receiving coil, an alumina ceramic coil frame, a low-frequency differential receiving coil, a magnetic core positioning yoke, a high-temperature resistant nanocrystalline magnetic core, an electromagnetic transmitting coil, and a laser interferometric coaxiality calibrator. The electromagnetic transmitting coil is mounted on the main frame, the low-frequency differential receiving coil is mounted on the inner side of the arc-shaped movable body, and the high-temperature resistant nanocrystalline magnetic core and the magnetic core positioning yoke are mounted in the cavity between the silicon carbide well casing and the composite heat insulation layer, and together they form a signal transceiver module for capturing the differences in the electromagnetic characteristics of multiphase flow. The laser interferometric coaxiality calibrator is mounted on both end faces of the main frame, with the transmitting end and the receiving end respectively aligned with the inner wall reference surface of the silicon carbide well casing, and coaxiality data is acquired in real time through the principle of optical interference.

[0012] Preferably, a magnetic shielding and anti-interference unit is installed on the wellbore simulation unit. The magnetic shielding and anti-interference unit includes a second-order active low-pass filter and a high-temperature magnetic shield. One or more sets of second-order active low-pass filters are installed on the outer wall of the silicon carbide wellbore. The second-order active low-pass filters are connected to a low-frequency differential receiving coil and a high-frequency low-parasitic receiving coil through signal cables to perform noise reduction processing on the acquired electromagnetic signals. The high-temperature magnetic shield is located between the upper cover and the base and is used to wrap the MIT magnetic induction imaging unit to isolate external electromagnetic interference.

[0013] Preferably, the temperature and pressure monitoring unit includes a temperature and pressure detector and a wellbore flow velocity detector. The temperature and pressure detector is embedded in the inner wall of the silicon carbide wellbore to collect temperature and pressure data in the wellbore in real time. The wellbore flow velocity detector adopts a non-contact design and is installed on the outer side of the middle section of the silicon carbide wellbore to monitor the fluid flow velocity and avoid interference with the flow field.

[0014] Preferably, the data processing and 3D imaging unit includes a high-precision lock-in amplifier and a computer data processing system. The high-precision lock-in amplifier is mounted on the main frame and is connected to a high-frequency low-parasitic receiving coil and a low-frequency differential receiving coil via signal cables to amplify weak electromagnetic signals. The computer data processing system is connected to a temperature and pressure detector, a wellbore flow velocity detector, and the high-precision lock-in amplifier via signal cables to acquire electromagnetic signals in real time and reconstruct a multiphase flow 3D image using the MIT tomography algorithm, simultaneously displaying the data and visualization results.

[0015] Preferably, an SMA compensation pad is also installed on the central gear. The SMA compensation pad is used to achieve signal impedance matching, and the signal from the SMA compensation pad is sent to the computer data processing system through a signal cable.

[0016] Preferably, a TEC cooling array is also installed on the outer side of the middle section of the silicon carbide wellbore.

[0017] The method of using the high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging mentioned in this invention includes the following steps:

[0018] The first step involves installing the silicon carbide wellbore in the middle of the first, second, and third center diameter changing mechanisms. The upper connecting rod is installed in the involute arc-shaped slots of the first and second center diameter changing mechanisms, with the lower end of the upper connecting rod connected to the lower connecting rod. The lower end of the lower connecting rod is installed in the involute arc-shaped slot of the third center diameter changing mechanism. High-frequency low-parasitic receiving coils, low-frequency differential receiving coils, and electromagnetic transmitting coils are installed on the first, second, and third center diameter changing mechanisms, respectively. A high-temperature resistant nanocrystalline magnetic core and a magnetic core positioning yoke are installed in the cavity between the silicon carbide wellbore and the composite insulation layer. A second-order active low-pass filter is used to calibrate the signal baseline to ensure the equipment is free from electromagnetic interference. A high-temperature magnetic shield and base are installed externally, and a top cover is installed on the top.

[0019] The second step is to connect the three-phase experimental fluid to the silicon carbide wellbore through a pipeline, start the TEC cooling array, and, in conjunction with the feedback data from the temperature and pressure detector, adjust the temperature of the cavity between the high-temperature magnetic shield and the composite insulation layer to the experimental set value.

[0020] The third step involves controlling the motor to start the pinion, which drives the meshing central gear to rotate. This causes the upper ends of multiple upper connecting rods to move along multiple involute arc-shaped slots on the central gear, causing the alumina ceramic coil frame to extend outward or retract inward, thus realizing the extension and retraction of the arc-shaped moving body and achieving the diameter change of the first central diameter changing mechanism. Simultaneously, since the upper connecting rods connect to the lower connecting rods, the second and third central diameter changing mechanisms are driven to change diameters at the same time. This adjusts the distance between the outer low-frequency differential receiving coil and the electromagnetic transmitting coil, enabling them to work together to form three sets of signal transceiver modules to capture the multiphase flow electromagnetic characteristics inside the silicon carbide well. After that, the motor on the pinion is turned off, and the device is rotated again.

[0021] By driving the rotating connecting rod to rotate along the rotating track, the first center diameter changing mechanism, the second center diameter changing mechanism, and the third center diameter changing mechanism rotate synchronously. After determining the target coil speed, the speed detector provides real-time feedback of the rotation speed data to ensure stable speed. The laser interferometric coaxiality calibrator works continuously, issuing an alarm and automatically calibrating when abnormalities occur.

[0022] The fourth step involves the computer data processing system connecting to the temperature and pressure detector, wellbore flow velocity detector, high-precision lock-in amplifier, and SMA compensation pad via signal cables. This system acquires electromagnetic signals in real time, records pressure, temperature, and flow velocity data at each measurement point, as well as signal data acquired by the electromagnetic transmitting coil, low-frequency differential receiving coil, and high-frequency low-parasitic receiving coil. The system amplifies the weak electromagnetic signals using a high-precision lock-in amplifier, performs noise reduction on the acquired electromagnetic signals using a second-order active low-pass filter, and then reconstructs the three-dimensional image of the multiphase flow using the MIT tomography algorithm. The system simultaneously displays the data and visualization results, obtaining the three-dimensional spatial distribution morphology, flow pattern, and dynamic transport trajectory of the multiphase flow.

[0023] Fifth, change the gas injection rate and liquid injection rate into the silicon carbide wellbore to the discharge rate required for the next set of experiments, and repeat the above steps to complete the multiphase flow monitoring simulation experiment under different operating conditions.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. This invention can adapt to high temperature and high pressure environments. By using materials resistant to extreme environments such as silicon carbide wellbore and high temperature resistant nanocrystalline magnetic core, combined with composite heat insulation layer and sealing structure, it can work stably under conditions of 0-250℃ and 0-200MPa, covering the simulation of typical working conditions of deep oil and gas development.

[0026] 2. This invention incorporates a dual-coil architecture, consisting of a low-frequency differential receiving coil and a high-frequency low-parasitic receiving coil, installed on the first, second, and third center diameter changing mechanisms respectively. This achieves frequency domain complementarity, enabling an imaging strategy of "low-frequency shaping and high-frequency microscopy," thus improving overall imaging contrast and noise resistance. During adjustment, the rotation of the driving pinion causes the central gear to rotate, moving the upper connecting rod along the involute arc-shaped slot. This causes the alumina ceramic coil frame to extend outward or retract inward, realizing the extension and retraction of the arc-shaped movable body, thereby achieving the first center diameter changing mechanism. The diameter of the first, second, and third center diameter changing mechanisms is achieved through the connection of the upper and lower connecting rods. This allows for the synchronous diameter changing of the second and third center diameter changing mechanisms, facilitating the rapid determination of the optimal distance for the low-frequency differential receiving coil to receive the magnetic signal before stopping the diameter changing. Furthermore, the rotating connecting rod enables the synchronous rotation of the first, second, and third center diameter changing mechanisms, allowing for circumferential scanning of the three-phase experimental fluid within the silicon carbide wellbore. This facilitates the fusion processing of multi-band electromagnetic signals and flow pattern component data, enabling precise reconstruction of the three-dimensional spatial distribution, flow pattern, and dynamic transport trajectory of the multiphase flow.

[0027] 3. The magnetic induction detection method used in this invention does not require contact with the fluid, thus avoiding interference with the flow field caused by traditional contact detection. It also eliminates radiation pollution, ensuring high experimental safety. The magnetic signal has strong anti-interference capabilities, high imaging resolution, and enables the monitoring of three-phase experimental fluids. It achieves high monitoring accuracy and good results under complex working conditions, which is of great significance for promoting the advancement of deep oil and gas drilling and development technology. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2 This is a schematic diagram of the overall structure of the present invention tilted upward at a certain angle;

[0030] Figure 3 This is a three-dimensional structural diagram of the upper cover and silicon carbide well casing;

[0031] Figure 4 This is a schematic diagram of the installation structure of the upper cover and the first central diameter changing mechanism;

[0032] Figure 5 This is a three-dimensional structural diagram of the first central variable diameter mechanism;

[0033] Figure 6 This is a three-dimensional structural diagram of the first central variable diameter mechanism from another angle;

[0034] Figure 7 This is a schematic diagram of the first central variable diameter mechanism viewed from below;

[0035] Figure 8 This is a schematic diagram of the expanded first center diameter changing mechanism;

[0036] Figure 9 This is a schematic diagram of the first central variable diameter mechanism after it has been contracted;

[0037] In the diagram: 1. Upper cover; 2. Second center diameter changing mechanism; 3. Silicon carbide wellbore; 4. Rotating connecting rod; 5. Silica aerogel; 6. High-temperature magnetic shield; 7. Base; 8. Temperature and pressure detector; 9. Wellbore flow velocity detector; 10. TEC cooling chip array; 11. Lower connecting rod; 12. Second-order active low-pass filter; 13. Upper connecting rod; 14. First center diameter changing mechanism; 15. Rotating track; 16. Pinion; 17. High-frequency low-parasitic receiving coil; 18. Alumina ceramic coil frame; 19. Center gear; 20. SMA compensation pad; 21. Low-frequency differential receiving coil; 22. High-precision lock-in amplifier; 23. Composite heat insulation layer; 24. Magnetic core positioning yoke; 25. High-temperature resistant nanocrystalline magnetic core; 26. Electromagnetic emission coil; 27. Laser interferometric coaxiality calibrator; 28. Third center diameter changing mechanism; 29. ​​Main frame; 14.1. Arc-shaped moving body; 14.2. Involute arc-shaped slot; 20.1. Detailed Implementation

[0038] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0039] Example 1, referring to Figures 1-9 The present invention mentions a high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging, which includes a temperature and pressure monitoring unit, a data processing and three-dimensional imaging unit, a wellbore simulation unit and an MIT magnetic induction imaging unit, wherein the MIT magnetic induction imaging unit is installed on the wellbore simulation unit.

[0040] The wellbore simulation unit includes an upper cover 1, a silicon carbide wellbore 3, a rotating connecting rod 4, a base 7, an upper connecting rod 13, a lower connecting rod 11, a first central diameter changing mechanism 14, a second central diameter changing mechanism 2, and a third central diameter changing mechanism 29. The silicon carbide wellbore 3, the first central diameter changing mechanism 14, the second central diameter changing mechanism 2, and the third central diameter changing mechanism 29 are installed between the upper cover 1 and the base 7. The silicon carbide wellbore 3 is filled with a three-phase experimental fluid to adapt to the simulation requirements of different well diameters, and the silicon carbide wellbore 3 is mounted on the first central diameter changing mechanism 14, the second central diameter changing mechanism 2, and the third central diameter changing mechanism 29. The center of the diameter changing mechanism 29; a composite heat insulation layer 24 is installed on the outside of the silicon carbide well barrel 3, and the cavity between the silicon carbide well barrel 3 and the composite heat insulation layer 24 and the inner cavity of the high temperature magnetic shield 6 are respectively filled with silica aerogel 5; an annular rotating track 16 is set on the upper cover 1, the upper end of the rotating connecting rod 4 passes through the rotating track 16, and the lower end of the rotating connecting rod 4 is connected to the upper surface of the first central diameter changing mechanism 14; the lower end of the first central diameter changing mechanism 14 is connected to the second central diameter changing mechanism 2 through the upper connecting rod 13, and the lower end of the second central diameter changing mechanism 2 is connected to the third central diameter changing mechanism 29 through the lower connecting rod 11.

[0041] Reference Figures 3-9The first center-diameter-changing mechanism 14 mentioned in this invention includes a main frame 14.1, an arc-shaped movable body 14.2, a pinion 17, an alumina ceramic coil frame 19, and a center gear 20. A silicon carbide well casing 3 and a composite heat insulation layer 24 are installed at the center of the main frame 14.1. The center gear 20 is installed on the upper side of the main frame 14.1, and the outer side of the center gear 20 meshes with the pinion 17. The rotation of the pinion 17 drives the rotation of the center gear 20. Multiple involute arc-shaped slots 20.1 are provided at the center of the center gear 20, and the upper ends of multiple upper connecting rods 13 pass through the involute arc-shaped slots 20.1 for fixation. The upper connecting rod 13 is connected to the end of the alumina ceramic coil frame 19. The lower end of the upper connecting rod 13 is connected to the involute arc-shaped slot 20.1 of the second center diameter changing mechanism 2. The outer end of the alumina ceramic coil frame 19 is connected to the arc-shaped movable body 14.2. The inner end of the alumina ceramic coil frame 19 is inserted into the inner cavity of the main frame 14.1. When the center gear 20 rotates, the upper connecting rod 13 moves along the involute arc-shaped slot 20.1, causing the alumina ceramic coil frame 19 to extend outward or retract inward, thereby realizing the extension and retraction of the arc-shaped movable body 14.2, and thus realizing the diameter change of the first center diameter changing mechanism 14.

[0042] Reference Figure 4 , Figure 6 and Figure 7 The involute arc-shaped slot 20.1 mentioned in this invention is provided in five groups, which extend from the center of the central gear 20 to the periphery. Each group of involute arc-shaped slots 20.1 is provided with an upper connecting rod 13. The five upper connecting rods 13 expand or contract along the involute arc-shaped slots 20.1, and at the same time drive the lower connecting rods 11 connected to the lower part to expand or contract along the involute arc-shaped slots 20.1 of the second central diameter changing mechanism 2 and the third central diameter changing mechanism 29.

[0043] Reference Figures 5-7The MIT magnetic induction imaging unit mentioned in this invention includes an alumina ceramic coil frame 19, a low-frequency differential receiving coil 22, a magnetic core positioning yoke 25, a high-temperature resistant nanocrystalline magnetic core 26, an electromagnetic transmitting coil 27, and a laser interferometric coaxiality calibrator 28. The electromagnetic transmitting coil 27 is mounted on the main frame 14.1, the low-frequency differential receiving coil 22 is mounted on the inner side of the arc-shaped movable body 14.2, the outer end of the alumina ceramic coil frame 19 is connected to the arc-shaped movable body 14.2, and the interior is inserted into the main frame 14.1 and connected to the upper connecting rod 13. The high-temperature resistant nanocrystalline magnetic core 26 and the magnetic core positioning yoke 25 are installed in the cavity between the silicon carbide well barrel 3 and the composite heat insulation layer 24, and together form a signal transceiver module for capturing the differences in the electromagnetic characteristics of multiphase flow. The laser interferometric coaxiality calibrator 28 is mounted on both end faces of the main frame 14.1, with the transmitting end and the receiving end aligned with the inner wall reference surface of the silicon carbide well barrel 3, and real-time coaxiality data is acquired through the principle of optical interference. The function of the alumina ceramic coil frame 19 is to improve its strength and prevent deformation from affecting the extension or retraction action.

[0044] In addition, a magnetic shielding and anti-interference unit is installed on the wellbore simulation unit. The magnetic shielding and anti-interference unit includes a second-order active low-pass filter 12 and a high-temperature magnetic shield 6. One or more sets of second-order active low-pass filters 12 are installed on the outer wall of the silicon carbide wellbore 3. The second-order active low-pass filters 12 are connected to the low-frequency differential receiving coil 22 and the high-frequency low-parasitic receiving coil 18 through signal cables to perform noise reduction processing on the collected electromagnetic signals. The high-temperature magnetic shield 6 is located between the upper cover 1 and the base 7 and is used to wrap the MIT magnetic induction imaging unit to isolate external electromagnetic interference.

[0045] Furthermore, the temperature and pressure monitoring unit mentioned in this invention includes a temperature and pressure detector 8 and a wellbore flow velocity detector 9. The temperature and pressure detector 8 is embedded in the inner wall of the silicon carbide wellbore 3 to collect temperature and pressure data in the wellbore in real time. The wellbore flow velocity detector 9 adopts a non-contact design and is installed on the outer side of the middle section of the silicon carbide wellbore 3 to monitor the fluid flow velocity and avoid interference with the flow field. In addition, a TEC cooling chip array 10 is also installed on the outer side of the middle section of the silicon carbide wellbore 3 to control the temperature of the cavity between the high-temperature magnetic shield 6 and the silicon carbide wellbore 3 outside the silicon carbide wellbore 3 within the suitable operating range of the instrument.

[0046] Furthermore, the data processing and three-dimensional imaging unit mentioned in this invention includes a high-precision lock-in amplifier 23 and a computer data processing system. The high-precision lock-in amplifier 23 is mounted on the main frame 14.1 and is connected to a high-frequency low-parasitic receiving coil 18 and a low-frequency differential receiving coil 22 via signal cables to amplify weak electromagnetic signals. The computer data processing system is connected to a temperature and pressure detector 8, a wellbore flow velocity detector 9, and the high-precision lock-in amplifier 23 via signal cables to acquire electromagnetic signals in real time and reconstruct a three-dimensional image of multiphase flow using the MIT tomography algorithm, simultaneously displaying data and visualization results with high imaging resolution.

[0047] Specifically, an SMA compensation pad 21 is also installed on the central gear 20. The SMA compensation pad 21 is used to achieve signal impedance matching, and the signal from the SMA compensation pad 21 is sent to the computer data processing system via a signal cable. The computer data processing system is a conventional technology well-known to those skilled in the art and will not be described in detail here. Furthermore, the structures of the second and third central diameter changing mechanisms 2 and 29 are similar to the first central diameter changing mechanism 14, except that the pinion 17 is not installed. The diameter changing and rotation of the second and third central diameter changing mechanisms 2 and 29 are achieved through the connection of the upper connecting rod 13 and the lower connecting rod 11.

[0048] The method of using the high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging mentioned in this invention includes the following steps:

[0049] First, the silicon carbide well barrel 3 is installed in the middle of the first center diameter changing mechanism 14, the second center diameter changing mechanism 2, and the third center diameter changing mechanism 29. The upper connecting rod 13 is installed in the involute arc-shaped slot 20.1 of the first center diameter changing mechanism 14 and the second center diameter changing mechanism 2. The lower end of the upper connecting rod 13 is connected to the lower connecting rod 11. The lower end of the lower connecting rod 11 is installed in the involute arc-shaped slot 20.1 of the third center diameter changing mechanism 29. The high-frequency low parasitic receiving coil 18, the low-frequency differential receiving coil 22, and the electromagnetic transmitting coil 27 are respectively installed on the first center diameter changing mechanism 14, the second center diameter changing mechanism 2, and the third center diameter changing mechanism 29. The high-temperature resistant nanocrystalline magnetic core 26 and the magnetic core positioning yoke 25 are installed in the cavity between the silicon carbide well barrel 3 and the composite heat insulation layer 24. The signal baseline is calibrated by the second-order active low-pass filter 12 to ensure that the equipment is free from electromagnetic interference. The high-temperature magnetic shield 6 and the base 7 are installed on the outside, and the top cover 1 is installed on the top.

[0050] The second step is to connect the high-temperature and high-pressure three-phase experimental fluid to the silicon carbide well 3 through the pipeline, start the TEC cooling array 10, and, combined with the feedback data of the temperature and pressure detector 8, adjust the temperature of the cavity between the high-temperature magnetic shield 6 and the composite heat insulation layer 24 to the experimental set value.

[0051] The third step involves controlling the motor to start the pinion 17, which drives the meshing center gear 20 to rotate. This causes the upper ends of multiple upper connecting rods 13 to move along multiple involute arc-shaped slots 20.1 on the center gear 20, causing the alumina ceramic coil frame 19 to extend outward or retract inward, thus extending and retracting the arc-shaped movable body 14.2, thereby achieving the diameter change of the first center diameter changing mechanism 14. Simultaneously, since the upper connecting rod 13 connects to the lower connecting rod 11, it drives the second center diameter changing mechanism 2 and the third center diameter changing mechanism 29 to change their diameters at the same time. This adjusts the distance between the outer low-frequency differential receiving coil 22 and the electromagnetic transmitting coil 27, enabling them to work together to form three sets of signal transceiver modules for capturing the multiphase flow electromagnetic characteristics within the silicon carbide wellbore 3. After that, the motor on the pinion 17 is turned off, and the device is rotated again.

[0052] By driving the rotating connecting rod 4 to rotate along the rotating track 16, the first center diameter changing mechanism 14, the second center diameter changing mechanism 2 and the third center diameter changing mechanism 29 are driven to rotate synchronously. After the target coil speed is determined, the speed detector 15 feeds back the rotation speed data in real time to ensure the speed is stable. The laser interference coaxiality calibrator 28 works continuously and issues an alarm and automatically calibrates when there is an abnormality.

[0053] In the fourth step, the computer data processing system is connected to the temperature and pressure detector 8, the wellbore flow velocity detector 9, the high-precision lock-in amplifier 23, and the SMA compensation pad 21 via signal cables. It collects electromagnetic signals in real time, records the pressure, temperature, and flow velocity data at each measurement point, as well as the signal data collected by the electromagnetic transmitting coil 27, the low-frequency differential receiving coil 22, and the high-frequency low-parasitic receiving coil 18. The weak electromagnetic signals are amplified by the high-precision lock-in amplifier 23, and the collected electromagnetic signals are denoised by the second-order active low-pass filter 12. Then, the MIT tomography algorithm is used to reconstruct the three-dimensional image of the multiphase flow, and the data and visualization results are displayed simultaneously to obtain the three-dimensional spatial distribution morphology, flow pattern, and dynamic transport trajectory of the multiphase flow.

[0054] Fifth, change the gas injection rate and liquid injection rate into the silicon carbide wellbore 3 to the discharge rate required for the next set of experiments, and repeat the above steps to complete the multiphase flow monitoring simulation experiment under different working conditions.

[0055] Example 2: The high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging mentioned in this invention includes a temperature and pressure monitoring unit, a data processing and three-dimensional imaging unit, a wellbore simulation unit and an MIT magnetic induction imaging unit, with the MIT magnetic induction imaging unit mounted on the wellbore simulation unit.

[0056] The wellbore simulation unit includes an upper cover 1, a silicon carbide wellbore 3, a rotating connecting rod 4, a base 7, an upper connecting rod 13, a lower connecting rod 11, a first central diameter changing mechanism 14, a second central diameter changing mechanism 2, and a third central diameter changing mechanism 29. The silicon carbide wellbore 3, the first central diameter changing mechanism 14, the second central diameter changing mechanism 2, and the third central diameter changing mechanism 29 are installed between the upper cover 1 and the base 7. The silicon carbide wellbore 3 is filled with a three-phase experimental fluid to adapt to the simulation requirements of different well diameters, and the silicon carbide wellbore 3 is mounted on the first central diameter changing mechanism 14, the second central diameter changing mechanism 2, and the third central diameter changing mechanism 29. The center of the diameter changing mechanism 29; a composite heat insulation layer 24 is installed on the outside of the silicon carbide well barrel 3, and the cavity between the silicon carbide well barrel 3 and the composite heat insulation layer 24 and the inner cavity of the high temperature magnetic shield 6 are respectively filled with silica aerogel 5; an annular rotating track 16 is set on the upper cover 1, the upper end of the rotating connecting rod 4 passes through the rotating track 16, and the lower end of the rotating connecting rod 4 is connected to the upper surface of the first central diameter changing mechanism 14; the lower end of the first central diameter changing mechanism 14 is connected to the second central diameter changing mechanism 2 through the upper connecting rod 13, and the lower end of the second central diameter changing mechanism 2 is connected to the third central diameter changing mechanism 29 through the lower connecting rod 11.

[0057] The difference from Example 1 is:

[0058] High-frequency low-parasitic receiving coils 18 are also installed on the first center diameter changing mechanism 14, the second center diameter changing mechanism 2 and the third center diameter changing mechanism 29 respectively. The high-frequency low-parasitic receiving coils 18 are installed on the lower surface of the main frame 14.1. The high-frequency low-parasitic receiving coils 18 significantly improve the sensitivity and spatial resolution of the high-temperature and high-pressure three-phase experimental fluid flowing through the silicon carbide well 3 due to their high Q value and low parasitic capacitance.

[0059] The above description is merely a partial preferred embodiment of the present invention. Any person skilled in the art can modify the above-described technical solutions or modify them into equivalent technical solutions. Therefore, any simple modifications or equivalent transformations made based on the technical solutions of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging, comprising a temperature and pressure monitoring unit and a data processing and three-dimensional imaging unit, characterized in that: It also includes a wellbore simulation unit and a MIT magnetic induction imaging unit, with the MIT magnetic induction imaging unit mounted on the wellbore simulation unit; The wellbore simulation unit includes an upper cover (1), a silicon carbide wellbore (3), a rotating connecting rod (4), a base (7), an upper connecting rod (13), a lower connecting rod (11), a first central diameter changing mechanism (14), a second central diameter changing mechanism (2), and a third central diameter changing mechanism (29). The silicon carbide wellbore (3), the first central diameter changing mechanism (14), the second central diameter changing mechanism (2), and the third central diameter changing mechanism (29) are installed between the upper cover (1) and the base (7). The silicon carbide wellbore (3) is filled with a three-phase experimental fluid to adapt to the simulation requirements of different well diameters. The silicon carbide wellbore (3) is installed on the first central diameter changing mechanism (14), the second central diameter changing mechanism (2), and the third central diameter changing mechanism (29). The center of the diameter mechanism (29); a composite heat insulation layer (24) is installed on the outside of the silicon carbide well barrel (3), and the cavity between the silicon carbide well barrel (3) and the composite heat insulation layer (24) and the inner cavity of the high temperature magnetic shield (6) are respectively filled with silica aerogel (5); an annular rotating track (16) is set on the upper cover (1), the upper end of the rotating connecting rod (4) passes through the rotating track (16), and the lower end of the rotating connecting rod (4) is connected to the upper surface of the first central diameter changing mechanism (14); the lower end of the first central diameter changing mechanism (14) is connected to the second central diameter changing mechanism (2) through the upper connecting rod (13), and the lower end of the second central diameter changing mechanism (2) is connected to the third central diameter changing mechanism (29) through the lower connecting rod (11). The first center diameter changing mechanism (14) includes a main frame (14.1), an arc-shaped movable body (14.2), a pinion (17), an alumina ceramic coil frame (19), and a center gear (20). A silicon carbide well barrel (3) and a composite heat insulation layer (24) are installed at the center of the main frame (14.1). The MIT magnetic induction imaging unit includes a high-frequency low-parasitic receiving coil (18), an alumina ceramic coil frame (19), a low-frequency differential receiving coil (22), a magnetic core positioning yoke (25), a high-temperature resistant nanocrystalline magnetic core (26), an electromagnetic transmitting coil (27), and a laser interference coaxiality calibrator (28). The electromagnetic transmitting coil (27) is installed on the main frame (14.1), the low-frequency differential receiving coil (22) is installed on the inner side of the arc-shaped movable body (14.2), and the high-temperature resistant nanocrystalline magnetic core (26) and the magnetic core positioning yoke (25) are installed in the cavity between the silicon carbide well barrel (3) and the composite heat insulation layer (24), and work together to form a signal transceiver module for capturing the differences in electromagnetic characteristics of multiphase flow. The laser interference coaxiality calibrator (28) is installed on both end faces of the main frame (14.1), with the transmitting end and the receiving end aligned with the inner wall reference surface of the silicon carbide well barrel (3), and coaxiality data is collected in real time through the principle of optical interference.

2. The high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging according to claim 1, characterized in that: A central gear (20) is installed on the upper side of the main frame (14.1). The outer side of the central gear (20) meshes with a small gear (17). The rotation of the small gear (17) drives the central gear (20) to rotate. Multiple involute arc-shaped slots (20.1) are provided in the center of the central gear (20). The upper ends of multiple upper connecting rods (13) pass through the involute arc-shaped slots (20.1) and are fixedly connected to the end of the alumina ceramic coil frame (19). The lower ends of the upper connecting rods (13) are connected to the involute arc-shaped slots (2) of the second central diameter changing mechanism (2). An arc-shaped slot (20.1) is opened, and the outer end of the alumina ceramic coil skeleton (19) is connected to the arc-shaped movable body (14.2). The inner end of the alumina ceramic coil skeleton (19) is inserted into the inner cavity of the main frame (14.1). When the central gear (20) rotates, the upper connecting rod (13) moves along the involute arc-shaped slot (20.1), causing the alumina ceramic coil skeleton (19) to extend outward or retract inward, thereby realizing the extension and retraction of the arc-shaped movable body (14.2) and thus realizing the diameter change of the first central diameter changing mechanism (14).

3. The high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging according to claim 2, characterized in that: The involute arc-shaped slot (20.1) is provided in five groups, which extend from the center of the central gear (20) to the periphery. Each group of involute arc-shaped slots (20.1) is provided with an upper connecting rod (13). The five upper connecting rods (13) expand or contract along the involute arc-shaped slots (20.1), and at the same time drive the lower connecting rods (11) connected to the lower part to expand or contract along the involute arc-shaped slots (20.1) of the second central diameter changing mechanism (2) and the third central diameter changing mechanism (29).

4. The high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging according to claim 3, characterized in that: A magnetic shielding and anti-interference unit is installed on the wellbore simulation unit. The magnetic shielding and anti-interference unit includes a second-order active low-pass filter (12) and a high-temperature magnetic shield (6). One or more second-order active low-pass filters (12) are installed on the outer wall of the silicon carbide wellbore (3). The second-order active low-pass filter (12) is connected to the low-frequency differential receiving coil (22) and the high-frequency low-parasitic receiving coil (18) through signal cables to perform noise reduction processing on the collected electromagnetic signals. The high-temperature magnetic shield (6) is located between the upper cover (1) and the base (7) and is used to wrap the MIT magnetic induction imaging unit and isolate external electromagnetic interference.

5. The high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging according to claim 4, characterized in that: The temperature and pressure monitoring unit includes a temperature and pressure detector (8) and a wellbore flow velocity detector (9). The temperature and pressure detector (8) is embedded in the inner wall of the silicon carbide wellbore (3) to collect temperature and pressure data in the wellbore in real time. The wellbore flow velocity detector (9) adopts a non-contact design and is installed on the outer side of the middle section of the silicon carbide wellbore (3) to monitor the fluid flow velocity and avoid interference with the flow field.

6. The high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging according to claim 5, characterized in that: The data processing and three-dimensional imaging unit includes a high-precision lock-in amplifier (23) and a computer data processing system. The high-precision lock-in amplifier (23) is installed on the main frame (14.1). The high-precision lock-in amplifier (23) is connected to the high-frequency low-parasitic receiving coil (18) and the low-frequency differential receiving coil (22) through signal cables to amplify weak electromagnetic signals. The computer data processing system is connected to the temperature and pressure detector (8), the wellbore flow velocity detector (9), and the high-precision lock-in amplifier (23) through signal cables to collect electromagnetic signals in real time and reconstruct the three-dimensional image of multiphase flow through the MIT tomography algorithm, and simultaneously display the data and visualization results.

7. The high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging according to claim 6, characterized in that: An SMA compensation pad (21) is also installed on the center gear (20). The SMA compensation pad (21) is used to achieve signal impedance matching. The signal of the SMA compensation pad (21) is sent to the computer data processing system through the signal cable.

8. The high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging according to claim 7, characterized in that: A TEC cooling array (10) is also installed on the outer side of the middle section of the silicon carbide wellbore (3).

9. A method of using the high-temperature and high-pressure wellbore multiphase flow visualization device based on MIT imaging as described in claim 8, characterized in that: Includes the following processes: First, the silicon carbide well casing (3) is installed in the middle of the first center diameter changing mechanism (14), the second center diameter changing mechanism (2), and the third center diameter changing mechanism (29). The upper connecting rod (13) is installed in the involute arc-shaped slot (20.1) of the first center diameter changing mechanism (14) and the second center diameter changing mechanism (2). The lower end of the upper connecting rod (13) is connected to the lower connecting rod (11), and the lower end of the lower connecting rod (11) is installed in the involute arc-shaped slot (20.1) of the third center diameter changing mechanism (29). In the first center diameter changing mechanism ( 14) The high-frequency low parasitic receiving coil (18), the low-frequency differential receiving coil (22) and the electromagnetic transmitting coil (27) are respectively installed on the second center diameter changing mechanism (2) and the third center diameter changing mechanism (29). Among them, the high-temperature resistant nanocrystalline magnetic core (26) and the magnetic core positioning yoke (25) are installed in the cavity between the silicon carbide well barrel (3) and the composite heat insulation layer (24). The signal baseline is calibrated by the second-order active low-pass filter (12) to ensure that the equipment is free from electromagnetic interference. The high-temperature magnetic shield (6) and the base (7) are installed on the outside, and the top cover (1) is installed on the top. The second step is to connect the three-phase experimental fluid to the silicon carbide well (3) through the pipeline, start the TEC cooling array (10), and combine the feedback data of the temperature and pressure detector (8) to adjust the temperature of the cavity between the high temperature magnetic shield (6) and the composite heat insulation layer (24) to the experimental set value. The third step involves controlling the motor to start the pinion (17), which drives the meshing center gear (20) to rotate. This causes the upper ends of multiple upper connecting rods (13) to move along multiple involute arc-shaped slots (20.1) on the center gear (20), thereby causing the alumina ceramic coil frame (19) to extend outward or retract inward, thus achieving the extension and retraction of the arc-shaped moving body (14.2), thereby achieving the diameter change of the first center diameter changing mechanism (14). At the same time, since the upper connecting rod (13) connects to the lower connecting rod (11), it drives the second center diameter changing mechanism (2) and the third center diameter changing mechanism (29) to change diameter simultaneously, thereby adjusting the distance between the outer low-frequency differential receiving coil (22) and the electromagnetic transmitting coil (27), thus achieving the coordinated formation of three sets of signal transceiver modules for capturing the multiphase flow electromagnetic characteristics inside the silicon carbide wellbore (3). After that, the motor on the pinion (17) is turned off, and the device is rotated again. By driving the rotating connecting rod (4) to rotate along the rotating track (16), the first center diameter changing mechanism (14), the second center diameter changing mechanism (2) and the third center diameter changing mechanism (29) are driven to rotate synchronously. After the target coil speed is determined, the speed detector (15) feeds back the rotation speed data in real time to ensure the speed is stable. The laser interference coaxiality calibrator (28) works continuously and issues an alarm and automatically calibrates when there is an abnormality. In the fourth step, the computer data processing system is connected to the temperature and pressure detector (8), wellbore flow velocity detector (9), high-precision lock-in amplifier (23), and SMA compensation pad (21) via signal cables to collect electromagnetic signals in real time, record the pressure, temperature, and flow velocity data at each measurement point, as well as the signal data collected by the electromagnetic transmitting coil (27), low-frequency differential receiving coil (22), and high-frequency low-parasitic receiving coil (18). The weak electromagnetic signals are amplified by the high-precision lock-in amplifier (23), and the collected electromagnetic signals are denoised by the second-order active low-pass filter (12). The three-dimensional image of the multiphase flow is reconstructed by the MIT tomography algorithm, and the data and visualization results are displayed simultaneously to obtain the three-dimensional spatial distribution morphology, flow pattern, and dynamic transport trajectory of the multiphase flow. Fifth step, change the gas injection volume and liquid injection volume into the silicon carbide wellbore (3) to the discharge volume required for the next set of experiments, repeat the above steps, and complete the multiphase flow monitoring simulation experiment under different working conditions.

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