Looped tubing experimental system and detection method for multiplex detection method

Abstract

This invention relates to a circulating pipeline experimental system and detection method for multiple detection methods, and pertains to the field of flow safety monitoring technology for oil and gas transportation pipelines. To address the issue of comprehensively improving the accuracy and efficiency of pipeline blockage detection, the key features include a main pipeline and a pipeline blockage detection device installed on the main pipeline. The pipeline blockage detection device includes an ultrasonic sensor (comprising a sound wave emitting device and a first and second sound wave receiving device); a pressure wave sensor (comprising a first static pressure sensor, a dynamic pressure sensor, and a second static pressure sensor); a fiber optic sensor (comprising an optical fiber and a fiber optic sensing system); an ERT sensor (comprising an electrical resistance tomography module); and pressure and temperature sensors. This invention constructs a sensor array, integrating ultrasonic, pressure wave, fiber optic sensing, and electrical resistance tomography technologies, along with temperature and pressure data within the pipeline, to monitor the pipeline status in real time, accurately identify blockages, and comprehensively ensure the safety of oil and gas pipelines.

Description

Technical Field

[0001] This invention relates to the field of flow safety monitoring technology for oil and gas pipelines, specifically for blockage detection. By fusing multimodal data from ultrasonic waves, pressure waves, fiber optic sensor arrays, and resistive tomography, it enables real-time monitoring of pipeline status, accurate identification and location of various faults, and is widely used in safety monitoring of oil and natural gas pipelines. Background Technology

[0002] As the proportion of natural gas in my country's energy consumption increases year by year, the mileage of natural gas transmission pipelines continues to grow. During the gas transmission process, impurities such as water, condensate oil, and hydrates accumulate in the pipelines, which may lead to blockages; pipelines may also leak due to mechanical damage, corrosion, design defects, or long-term aging. These problems can not only cause production stoppages and reduced efficiency, but in severe cases, they may also cause fires and explosions, resulting in serious environmental pollution and resource waste. Simulating these situations can simulate the blockages that occur during leaks.

[0003] Acoustic wave detection technology is widely used for blockage detection due to its simple installation, long detection distance, reliable data, and lack of safety risks. Pressure wave detection technology has advantages such as fast response, low cost, non-contact operation, and high precision, enabling rapid location of blockages. Fiber optic sensing technology monitors hydrate blockages by utilizing changes in light transmittance and has strong environmental adaptability. Electrical resistance tomography (ERT) technology provides a clear image of the pipeline's condition by observing changes in flow patterns within the pipe. However, in complex pipeline environments, especially with multiple leaks and interference noise, ultrasonic sensors struggle to fully reflect the pipeline's condition, resulting in limited detection accuracy. Pressure wave sensors may experience signal attenuation or reflection due to the complex structure and variable flow conditions within the pipeline, affecting detection accuracy. Fiber optic sensing technology is susceptible to mechanical damage, has high installation costs, stringent environmental requirements, and complex systems. Electrical resistance tomography (ERT) technology, due to its limitations in imaging accuracy and real-time performance, is not ideal when used alone.

[0004] Therefore, by utilizing sensor arrays and data fusion, and integrating the advantages of technologies such as ultrasonic waves, pressure waves, fiber optics, and ERT, the limitations of each individual technology are overcome, comprehensively improving the accuracy and efficiency of pipeline blockage detection, especially in the presence of pipeline leaks. This multi-sensor collaborative approach enables precise monitoring of pipeline conditions under complex operating conditions, ensuring the safety of natural gas transportation. Summary of the Invention

[0005] To address the issue of comprehensively improving the accuracy and efficiency of pipeline blockage detection, according to a first aspect of some embodiments of this application, a circulating pipeline testing system for multiple detection methods according to some embodiments of this application includes a main pipeline and a pipeline blockage detection device disposed on the main pipeline;

[0006] The main pipe is formed as several spiral rectangles that wrap around from the inside to the outside on the same plane. Each ring of the main pipe includes a straight pipe and a bend that connects two straight pipes and turns them.

[0007] Among them, the innermost ring pipe and the middle ring pipe of the main pipeline include a first vertical straight pipe and a second vertical straight pipe arranged vertically opposite each other, and a first horizontal straight pipe and a second horizontal straight pipe arranged horizontally opposite each other.

[0008] The outermost straight pipe of the main pipeline includes a first vertical straight pipe and a second vertical straight pipe arranged vertically opposite each other, as well as a first horizontal straight pipe;

[0009] Among them, the vertical straight pipes are parallel to each other, and the horizontal straight pipes are parallel to each other;

[0010] The innermost horizontal straight pipe of the main pipeline is provided with the innermost outlet, and the outermost vertical straight pipe of the main pipeline is provided with the outermost inlet.

[0011] Among them, the pipeline blockage detection device includes

[0012] An ultrasonic sensor includes a sound wave emitting device, a first sound wave receiving device, and a second sound wave receiving device;

[0013] The pressure wave sensor includes a first static pressure sensor, a dynamic pressure sensor, and a second static pressure sensor;

[0014] Fiber optic sensors, including optical fibers and fiber optic sensing systems;

[0015] ERT sensors, including an electrical resistance tomography module; and

[0016] Pressure sensor and temperature sensor.

[0017] According to some embodiments of this application, a circulating pipeline experimental system for a multiple detection method, a pipeline blockage detection device, further includes a fourth solenoid valve, a fifth solenoid valve, and a high-speed camera.

[0018] A sound wave emitting device is installed on the second horizontal straight pipe of the innermost ring of the main pipeline;

[0019] Among them, a first acoustic wave receiving device is installed on the second horizontal straight pipe of each ring of the main pipeline. Each first acoustic wave receiving device is arranged in a vertically opposite and parallel manner and is located upstream of the first acoustic wave receiving device.

[0020] Among them, a fourth solenoid valve is installed on the first vertical straight pipe of each ring of the main pipeline. The fourth solenoid valves are arranged in parallel opposite directions in the horizontal direction and are located upstream of the first sound wave receiving device. The fourth solenoid valve is used to simulate the leakage of the submarine pipeline.

[0021] Among them, a second acoustic wave receiving device is installed on the first horizontal straight pipe of each ring of the main pipeline. Each second acoustic wave receiving device is arranged vertically opposite and parallel to each other, and is located upstream of the fourth solenoid valve; the first acoustic wave receiving device and the second acoustic wave receiving device are arranged vertically opposite and parallel to each other.

[0022] Among them, the first static pressure sensor, the fifth solenoid valve, the dynamic pressure sensor and the second static pressure sensor are sequentially installed on the first transverse straight pipe of the innermost ring of the main pipeline along the upstream direction. The first static pressure sensor is located upstream of the second acoustic wave receiving device, and the opening and closing of the fifth solenoid valve is used to generate pressure waves.

[0023] Among them, optical fibers are laid in each ring of the main pipeline, and the optical fiber sensing system is set outside the main pipeline to receive optical fiber signals.

[0024] Transparent tube segments and resistance tomography modules are installed on the first and second vertical straight tubes of the innermost ring of the main pipeline. The transparent tube segments are arranged relatively parallel in the horizontal direction, and the resistance tomography modules are arranged relatively parallel in the horizontal direction.

[0025] The high-speed camera is set outside the main pipe, and the transparent pipe section is within the high-speed camera's field of view;

[0026] Pressure and temperature sensors are installed on at least one straight pipe in at least one loop of the main pipeline.

[0027] The circulating pipeline test system for multiple detection methods according to some embodiments of this application further includes an injection branch, a connecting pipeline, a circulating screw pump, a first tee, a drainage branch, a second tee, an air injection branch, an air exhaust branch, a first branch, and a third tee.

[0028] The injection branch includes an injection branch pipeline and a storage tank, a supply pump, a liquid flow meter, and a first solenoid valve arranged sequentially along the downstream direction on the injection branch pipeline. The first solenoid valve is located at the outlet end of the injection branch pipeline.

[0029] The connecting pipe is set between the innermost outlet of the innermost ring of the main pipe and the outermost inlet of the outermost ring of the main pipe. A circulating screw pump is installed on the connecting pipe. The innermost outlet is the second horizontal straight pipe outlet of the innermost ring of the main pipe, and the outermost inlet is the second vertical straight pipe inlet of the outermost ring of the main pipe.

[0030] The first inlet of the first tee is connected to the outlet of the injection branch pipeline, the second inlet of the first tee is connected to the outlet of the pipeline, and the outlet of the first tee is connected to the outermost inlet of the outermost ring of the main pipeline.

[0031] The drainage branch includes a drainage branch pipeline and a manual gate valve, a second solenoid valve, and a waste liquid collection tank, which are sequentially installed along the downstream direction on the drainage branch pipeline. The manual gate valve is installed at the inlet end of the drainage branch pipeline.

[0032] The inlet of the second tee is connected to the outlet of the innermost innermost loop of the main pipeline, the first outlet of the second tee is connected to the inlet of the drainage branch pipeline, and the second outlet of the second tee is connected to the outlet of the pipeline.

[0033] The gas injection branch includes a gas injection branch pipeline and a gas cylinder, a pressure stabilizing tank, a pressure sensor, a gas flow meter, a third solenoid valve, and a first needle valve arranged sequentially along the downstream direction on the gas injection branch pipeline. The first needle valve is located at the outlet end of the gas injection branch pipeline.

[0034] The exhaust branch includes an exhaust branch pipe and a gas flow solenoid valve, a second needle valve, and a waste gas recovery and treatment device arranged sequentially along the downstream direction on the exhaust branch pipe. The gas flow solenoid valve is located at the inlet end of the exhaust branch pipe.

[0035] The first branch includes the first branch pipeline, and the first port of the first branch pipeline is connected to the second transverse straight pipe upstream of the innermost outlet of the innermost pipeline of the main pipeline.

[0036] The first valve port of the third tee is connected to the second port of the first branch, the second valve port of the third tee is connected to the inlet of the drain branch pipe, and the third valve port of the third tee is connected to the inlet of the exhaust branch pipe.

[0037] According to some embodiments of the present application, in a circulating pipeline experimental system for a multiple detection method, the acoustic wave emitting device is disposed on the second transverse straight pipe of the innermost ring of the main pipeline upstream of the first branch.

[0038] The connecting pipeline includes a horizontal section and a first vertical section and a second vertical section located at both ends of the horizontal section and connected to the horizontal section. A circulating screw pump is located in the horizontal section of the connecting pipeline. The second outlet of the second tee is connected to the inlet of the first vertical section of the pipeline, and the second inlet of the first tee is connected to the outlet of the second vertical section of the pipeline.

[0039] In a second aspect, the system described above is used for detection of hydrate blockage in circulating pipelines according to some embodiments of this application;

[0040] Open the manual gate valve of the drainage branch and close the second solenoid valve;

[0041] Open the first solenoid valve and the supply pump of the injection branch, and inject the oil-water mixture to the preset liquid level by controlling the inlet flow rate through the liquid flow meter and the first solenoid valve to the outermost inlet of the outermost ring of the main pipeline.

[0042] Turn on the circulating screw pump;

[0043] Open the methane cylinder in the gas injection branch, and control the amount of methane gas injected through the pressure stabilizing tank, pressure sensor, gas flow meter and third solenoid valve to maintain the pressure conditions required for the experiment.

[0044] Set the ambient temperature to the typical seabed temperature;

[0045] Under the above conditions, hydrates are formed in the main pipeline;

[0046] The sound wave transmitting device is activated to send out sound waves, and the first and second sound wave receiving devices receive the reflected sound wave signals.

[0047] The fifth solenoid valve is opened and closed to emit a pressure wave, and the first static pressure sensor, dynamic pressure sensor and second static pressure sensor collect the pressure reflection wave signal;

[0048] Start the fiber optic sensing system;

[0049] The resistivity tomography module and high-speed camera are activated to image the fluid inside the transparent tube section and acquire signals from temperature and pressure sensors to obtain images of the resistivity distribution of the fluid inside the pipe, as well as images of the fluid's dynamic changes and deposition.

[0050] Blockage can be inferred based on acoustic wave reflection time difference, pressure wave amplitude attenuation rate, fiber DAS flow noise intensity, ERT blockage cross-section evaluation, abnormal pressure difference, and abnormal temperature difference.

[0051] According to the circulating pipeline hydrate blockage detection method in some embodiments of this application, after the experiment, the first solenoid valve and the liquid supply pump of the injection branch are closed, all gas and oil / water sources are closed, the circulating screw pump is closed, and the second solenoid valve of the drainage branch and the gas flow solenoid valve of the exhaust branch are opened to discharge the waste liquid and waste gas in the pipeline.

[0052] According to the circulating pipeline hydrate blockage detection method in some embodiments of this application, the various detection anomaly evaluation criteria of the sensor are weighted and fused, and the blockage is inferred based on the characteristic signal after weighted fusion;

[0053] Among them, the evaluation criteria for various detection anomalies of different types of sensors include

[0054] Time difference of sound wave reflection from ultrasonic sensor ;

[0055] Pressure wave amplitude attenuation rate derived from pressure wave sensor ;

[0056] Attenuation of fiber optic DAS flow noise intensity from fiber optic sensors ;

[0057] Evaluation of ERT clogging sections derived from ERT sensors ;

[0058] Abnormal pressure difference originating from pressure sensor ;

[0059] Abnormal temperature difference originating from temperature sensor .

[0060] According to the circulating pipeline hydrate blockage detection method in some embodiments of this application, the sensor's various detection anomaly evaluation criteria are... , ... The weighted fusion result is the characteristic signal. It is expressed by the following formula:

[0061]

[0062] It is the i-th type of detection anomaly evaluation standard for the sensor. is the weight corresponding to the i-th type of anomaly evaluation standard of the sensor, and N is the number of anomaly evaluation standards.

[0063] According to the circulating pipeline hydrate blockage detection method in some embodiments of this application, the weights are obtained based on the following method:

[0064] Static weight allocation is performed based on sensor characteristics;

[0065] The weights are obtained by dynamically assigning weights based on real-time operating conditions.

[0066] The static weight allocation is derived from the acoustic wave reflection time difference of the ultrasonic sensor. static weights =0.5;

[0067] Pressure wave amplitude attenuation rate derived from pressure wave sensor static weights =0.25;

[0068] Attenuation of fiber optic DAS flow noise intensity from fiber optic sensors static weights =0.1;

[0069] Evaluation of ERT clogging sections derived from ERT sensors static weights =0.05;

[0070] Abnormal pressure difference originating from pressure sensor static weights =0.05;

[0071] Abnormal temperature difference originating from temperature sensor static weights =0.05;

[0072] Dynamic weight allocation includes

[0073] Adjust the pressure wave amplitude attenuation rate from the pressure wave sensor based on flow velocity changes. static weights and the attenuation of fiber optic DAS flow noise intensity from fiber optic sensors. static weights ;

[0074] And adjust the sound wave reflection time difference from the ultrasonic sensor according to noise interference. static weights And evaluation of ERT blockage cross-section derived from ERT sensors static weights .

[0075] According to the circulating pipeline hydrate blockage detection method in some embodiments of this application, the pressure wave amplitude attenuation rate from the pressure wave sensor is adjusted based on the flow velocity change. static weights and the attenuation of fiber optic DAS flow noise intensity from fiber optic sensors. static weights This includes the rapid attenuation of pressure wave signals when the flow rate increases, and the reduction of static weights. Increase static weights ;

[0076] Among them, the sound wave reflection time difference from the ultrasonic sensor is adjusted according to noise interference. static weights And evaluation of ERT blockage cross-section derived from ERT sensors static weights Static weights Increase static weights .

[0077] The beneficial effects of this invention are: by constructing a sensor array, this invention integrates technologies such as ultrasonic waves, pressure waves, fiber optic sensing and electrical resistance tomography, as well as temperature and pressure data inside the pipeline, to monitor the pipeline status in real time, accurately identify blockages, and comprehensively ensure the safety of oil and gas pipelines, especially improving the detection accuracy of blockages in the event of pipeline leaks.

[0078] Based on the above, acoustic detection, with its non-invasive nature and high sensitivity to blockages and leaks, offers a detection range of tens of kilometers. This invention installs an acoustic wave transmitter at the inner opening of the main pipe and several acoustic wave receivers to receive acoustic signals emitted from the circulating pipe. Acoustic wave generators and receivers are installed on the horizontal straight pipes to facilitate the axial propagation of the acoustic signals along the pipe and reduce interference from signal scattering due to bends. Installed on the innermost horizontal pipe, the emitted acoustic waves can propagate as far as possible from the innermost ring to the outermost ring to detect the condition of the outer ring pipe. The parallel arrangement ensures that the acoustic wave receivers are under the same hydrodynamic conditions. By comparing the time difference of reflected signals from different rings of pipe, interference factors such as flow velocity and pipe wall friction can be eliminated, improving the accuracy of blockage location. The parallel layout avoids the superposition of phase differences between different rings of pipe, reducing signal distortion.

[0079] Based on the above, this invention sets up several vertical branch pipes on the main pipeline, and installs a fourth solenoid valve on each branch pipe. Acoustic wave detection is achieved by using an acoustic wave emitting device installed on the pipeline to selectively transmit continuous or pulsed acoustic waves as needed. When the acoustic waves encounter a blockage in the pipeline, some of the sound waves are reflected back, while others may be scattered or absorbed. The nature and location of the blockage affect the characteristics of the reflected acoustic waves. After the signal from the blockage is received, the location of the blockage can be inferred by analyzing the arrival time of the reflected acoustic waves. Selectively opening several fourth solenoid valves, and changing the frequency, intensity, and duration of the valve opening changes, allows for the simulation of the location, size, and type of leaks, enabling the simulation of multi-point leaks in subsea pipelines.

[0080] Based on the above, the pressure wave detection of this invention can achieve dynamic monitoring and quickly locate sudden blockages without adding more sensors. A first static pressure sensor, a fifth solenoid valve, and a dynamic pressure sensor are sequentially installed in the circulation pipeline, with the first static pressure sensor and the dynamic pressure sensor positioned upstream and downstream of the fifth solenoid valve, respectively. The second static pressure sensor generates a pressure wave through the rapid opening and closing of the fifth solenoid valve. The first static pressure sensor, the dynamic pressure sensor, and the second static pressure sensor collect pressure signals. According to Bernoulli's equation, the static pressure sensor monitors the change in the fluid's potential energy, while the dynamic pressure sensor captures the change in kinetic energy. Combining these two data allows for the calculation of the total pressure drop in the pipeline, determining the energy loss caused by the blockage. The upstream static pressure sensor captures the initial amplitude of the pressure wave, while the downstream dynamic pressure sensor records the attenuated signal. Combining these two data allows for the inversion of the pressure wave attenuation coefficient, distinguishing between blockages and noise interference. To maintain the stability of the static and dynamic pressure sensor measurements and reduce the influence of the circulation pump, the pressure wave transmitter is installed near the inner ring of the pipeline, away from the circulation pump. The pressure wave propagates along the pipeline; if the pipeline is unobstructed, the pressure wave will reach the detection point smoothly; if there is a blockage in the pipeline, the propagation of the pressure wave will be hindered. When a pressure wave encounters a blockage, some of its energy is reflected back. These reflected waves can be received by placing pressure sensors at the other end of the pipe or along the pipe. This allows for real-time monitoring of pipe blockages.

[0081] Based on the above, the main pipeline of this invention is equipped with a fiber optic detection device. Utilizing optical fiber as a sensor, it enables continuous monitoring of the pipeline's condition over long distances. Environmental changes around the pipeline can be detected by measuring changes in the characteristics of light propagating through the fiber. The optical fiber is laid along the oil and gas pipeline, close to the outer wall. Data is periodically collected from the fiber optic sensing system, and the propagation characteristics of the light are analyzed to pinpoint the approximate location of leaks. Pipeline blockages can lead to increased pressure, causing strain or temperature changes in the pipeline wall. The fiber optic sensor can detect these changes in physical quantities, thereby identifying the location of the blockage. It can detect minute environmental changes and is highly sensitive to blockage detection. The fiber optic sensor can cover long distances of pipeline, enabling remote monitoring. The pipeline condition can be monitored in real time, allowing for timely problem detection. The fiber optic system is insensitive to electromagnetic interference and is suitable for various environments.

[0082] Based on the above, the main pipeline of this invention is equipped with an electrical resistance tomography (ERT) module to reconstruct an image of the internal structure of an object by measuring the electrical impedance distribution inside the object. A high-speed camera is installed near the transparent pipe section, and the ERT module is also installed near the transparent pipe section of the main pipeline. The ERT module and the high-speed camera work together to monitor the deposition of fluid in the pipeline, providing a more intuitive view of the flow, deposition, and blockage of hydrates. The ERT module is installed at the end furthest from the pump to reduce the impact of the pump and to maximize the visualization of the blockage.

[0083] Furthermore, to improve detection accuracy and reliability, this invention denoises the acquired signals and extracts features from different sensors, such as pressure wave changes and sound wave frequencies. All features are converted into dimensionless scalars and standardized, mapping all features to the [0,1] interval. The blockage determination criteria are weighted and fused according to the above-mentioned abnormality evaluation criteria, and the weights can be adjusted. This allows for optimized fusion of multi-sensor signals in existing systems, avoiding incomplete detection by a single sensor and preventing limitations imposed by sensors due to specific environmental influences. This significantly improves the accuracy and reliability of pipeline blockage detection. The fused signal features will avoid the problem of insufficient detection by a single sensor or a single type of sensor. Attached Figure Description

[0084] Figure 1 This is a structural block diagram of the circulating pipeline experimental system for multiple detection methods according to the present invention.

[0085] In the diagram: 1. Main pipe, 2. Connecting pipe, 3. First solenoid valve, 4. Liquid flow meter, 5. Liquid supply pump, 6. Liquid storage tank, 7. Circulating screw pump, 8. Second tee, 9. Manual gate valve, 10. Second solenoid valve, 11. Waste liquid collection tank, 12. Third tee, 13. First needle valve, 14. Third solenoid valve, 15. Gas flow meter, 16. Pressure sensor, 17. Pressure stabilizing tank, 18. Gas cylinder, 19. Gas flow solenoid valve, 20. Second needle valve, 21. Waste gas recovery and treatment device, 22. Acoustic wave transmitter, 231. First acoustic wave receiver, 232. Second acoustic wave receiver, 24. Fourth solenoid valve, 25. First static pressure sensor, 26. Fifth solenoid valve, 27. Dynamic pressure sensor, 28. Second static pressure sensor, 29. Fiber optic cable, 30. Electrical resistance tomography module, 31. High-speed camera, 32. First tee. Detailed Implementation

[0086] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0087] like Figure 1This invention describes a circulating pipeline system for detecting hydrate blockage using multiple detection methods. The system includes a circulating pipeline, injection branches, gas injection branches, drainage branches, and venting branches. To enable fluid circulation within the pipeline system, the circulating pipeline includes a main pipeline 1 and connecting pipelines 2 (U-shaped sections). The main pipeline 1 is formed into a spiral rectangle by several turns from the inside out. Each turn of the main pipeline 1 includes a straight pipe and a bend connecting and turning two straight pipes. The innermost and middle turns of the main pipeline 1 include vertically opposite first and second vertical straight pipes, and horizontally opposite first and second horizontal straight pipes. The outermost turn of the main pipeline 1 includes vertically opposite first and second vertical straight pipes, and a first horizontal straight pipe. The corresponding vertical straight pipes are parallel to each other, and the corresponding horizontal straight pipes are parallel to each other. The second horizontal straight pipe of the innermost turn of the main pipeline 1 has an innermost outlet, and the second vertical straight pipe of the outermost turn of the main pipeline 1 has an outermost inlet.

[0088] The outermost inlet and innermost outlet of the main pipeline 1 are connected by connecting pipeline 2 (U-shaped pipe section). The main pipeline 1 includes straight pipes of different lengths and multiple identical bends. The straight pipes are made of stainless steel or polysulfone (PSU) transparent pipes. Polysulfone material has advantages such as hydrolysis and dimensional stability, corrosion resistance, high toughness, and high light transmittance. The bends are made of stainless steel. The stainless steel pipes are connected by stainless steel pipe connectors. Stainless steel pipe connectors have the characteristics of flexible connection, quick installation, no need for hot work, sturdiness, durability, and strong versatility. The polysulfone (PSU) transparent pipes are connected to the stainless steel straight pipes and bends by flanges. The above-mentioned stainless steel pipe connector connections and flange connections should meet the pressure resistance requirement of not less than 10MPa. Connecting pipeline 2 (U-shaped pipe section) consists of three parts: a vertical pipe section connected to the outer opening of the main pipeline 1, a horizontal pipe section, and a vertical pipe section connected to the inner opening of the main pipeline 1. The vertical pipe of connecting pipeline 2 (U-shaped pipe section) is used to simulate the vertical pipe of the oil and gas transportation pipeline section.

[0089] A first tee 32 is installed at the vertical section of the connecting pipe 2 (U-shaped pipe section) connected to the outer opening end of the main pipe 1 to connect the injection branch. The injection branch includes a first solenoid valve 3, a liquid flow meter 4, a liquid supply pump 5, and a storage tank 6. Oil-water mixtures with different volume ratios according to experimental requirements are injected from the top of the storage tank 6. The storage tank 6 is connected to the liquid supply pump 5, which pumps the oil-water mixture in the storage tank 6 into the pipe to provide a sufficient and stable oil-water mixture for the experiment. The liquid flow meter 4 is connected before the liquid supply pump 5 to accurately measure the amount of liquid supplied for the experiment. The first solenoid valve 3 is connected before the liquid flow meter 4 to control the liquid inlet. The first solenoid valve 3 is connected to the tee through a stainless steel pipe to connect the injection branch to the main circulation pipe.

[0090] A circulating screw pump 7 is installed on the horizontal section of the connecting pipe (U-shaped pipe section) 2. The circulating screw pump 7 is connected to the horizontal pipe using a flange. The circulating screw pump 7 enables the fluid in the system to circulate. The circulating screw pump 7 must meet the following requirements: pressure resistance of at least 10MPa; slugs will appear in the circulating pipe to allow for dry running; the pipe is tested for pressure waves; the circulating screw pump 7 can withstand pressure waves; the rotation speed of the circulating screw pump 7 can be adjusted to simulate different flow rate conditions; and it can operate continuously. The vertical section of the connecting pipe (U-shaped pipe section) 2 is connected to the inner opening of the main pipe 1 using a second tee 8.

[0091] The other end of the second three-way valve 8 is connected to the drainage module, which includes a manual gate valve 9, a second solenoid valve 10, and a wastewater collection tank 11. The manual gate valve 9 and the second solenoid valve 10 control the waste liquid in the pipe to be discharged into the waste liquid collection tank 11. The manual gate valve 9 is normally open, and the second solenoid valve 10 is opened during the drainage stage after the experiment.

[0092] There is a vertically upward branch pipe at the inner opening of the main pipe 1, and a third tee 12 on the branch pipe. The other two ends of the third tee 12 on the branch pipe at the inner opening of the main pipe 1 are connected to an air injection branch and an air exhaust branch.

[0093] One end of the third tee 12 is connected to the gas injection branch, which includes a gas cylinder 18 to provide a sufficient gas source for the experiment. After the gas cylinder 18 is connected to the pressure stabilizing tank 17, the high-pressure gas is depressurized by the pressure stabilizing tank 17 and then connected in sequence to the pressure sensor 16 to accurately measure the injection pressure, the gas flow meter 15 to measure the volume flow rate of the gas injected into the circulation system, the third solenoid valve 14 to control the gas flow rate, and the first needle valve 13 to control the gas injection into the main circulation pipeline to maintain the pressure conditions required for the experiment. The rear end of the first needle valve 13 is connected to one end of the third tee 12 on the vertical branch at the opening of the inner ring of the main pipeline 1 through a stainless steel pipe. The first needle valve 13 is normally open, and the gas flow rate is controlled by the third solenoid valve 14, which is opened or closed as needed during the experiment.

[0094] The other end of the third tee 12 is connected to the exhaust branch, which includes a gas flow solenoid valve 19, a second needle valve 20, and a waste gas recovery and treatment device 21. The second needle valve 20 is connected to one end of the third tee 12 through a stainless steel pipe. The gas flow solenoid valve 19 is connected after the second needle valve 20, and a waste gas recovery and treatment device 21 is connected after the second needle valve 20 for recovering and treating experimental waste gas.

[0095] Acoustic wave detection, with a detection range of tens of kilometers, is non-invasive and highly sensitive to blockages and leaks. An acoustic wave transmitter 22 and several acoustic wave receivers 23 are installed at the inner opening of the main pipe 1 to receive acoustic wave signals emitted from within the circulating pipe. Acoustic wave generators and receivers are installed on the transverse straight pipes to facilitate the axial propagation of acoustic wave signals along the pipe and reduce interference from signal scattering due to bends. The receivers are installed on the innermost transverse pipe to ensure that the emitted acoustic waves propagate as far as possible from the innermost ring to the outermost ring, detecting the condition of the outermost pipe. Parallel arrangement ensures that the acoustic wave receivers are under the same hydrodynamic conditions. By comparing the time difference of reflected signals from different rings of pipe (…),… This eliminates interference factors such as flow velocity and pipe wall friction, improving blockage location accuracy. The parallel layout avoids the superposition of phase differences between different pipe loops, reducing signal distortion. Several vertical branch pipes are installed on the main pipe 1, and a fourth solenoid valve 24 is installed on each branch pipe. The specific installation positions are as follows... Figure 1 As shown. Acoustic wave detection uses an acoustic wave emitting device 22 installed on the pipeline to selectively transmit continuous or pulsed acoustic waves as needed. When the acoustic wave encounters a blockage in the pipeline, some of the sound wave is reflected back, while others may be scattered or absorbed. The nature and location of the blockage affect the characteristics of the reflected acoustic wave. After the signal after the blockage is received, the location of the blockage can be inferred by analyzing the arrival time of the reflected acoustic wave. Selectively opening several fourth solenoid valves 24, by changing the frequency, intensity, and duration of the opening changes of the fourth solenoid valves 24, can simulate the location, size, and type of leaks. It can simulate multi-point leaks in submarine pipelines. When a pipeline leaks, the sudden change in fluid pressure causes compression and expansion of the fluid within the pipeline, generating elastic waves. These waves propagate in the fluid as sound waves at a relatively high speed, usually close to the speed of sound in the fluid. However, in a pipeline, the sound wave will propagate along the pipeline. If the pipeline is unobstructed, the sound wave will reach the detection point smoothly; if there is a blockage or other obstacle in the pipeline, the propagation of the leaking sound wave will be hindered. Other detection methods are needed for detection.

[0096] Compared to acoustic sensors, pressure wave detection allows for dynamic monitoring and rapid location of sudden blockages without the need for additional sensors. In the circulation pipeline, a first static pressure sensor 25, a fifth solenoid valve 26, and a dynamic pressure sensor 27 are sequentially installed, with the first static pressure sensor 25 and the dynamic pressure sensor 27 positioned upstream and downstream of the fifth solenoid valve 26, respectively. A second static pressure sensor 28 generates a pressure wave through the rapid opening and closing of the fifth solenoid valve 26. Pressure signals are collected by the first static pressure sensor 25, the dynamic pressure sensor 27, and the second static pressure sensor 28. According to Bernoulli's equation, the static pressure sensor monitors changes in the fluid's potential energy, while the dynamic pressure sensor captures changes in kinetic energy. Combining these two data allows for the calculation of the total pressure drop in the pipeline, determining the energy loss caused by blockage. The upstream static pressure sensor captures the initial amplitude of the pressure wave, while the downstream dynamic pressure sensor records the attenuated signal. Combining these two data allows for the calculation of the pressure wave attenuation coefficient, distinguishing between blockages and noise interference. To maintain the stability of the static and dynamic pressure measurements and reduce the influence of the circulation pump, the pressure wave transmitter is installed near the inner edge of the pipeline, away from the circulation pump. Pressure waves propagate along pipes. If the pipe is unobstructed, the pressure waves will reach the detection point smoothly; if there is a blockage in the pipe, the propagation of the pressure waves will be hindered. When the pressure waves encounter a blockage, some of the energy is reflected back. These reflected waves can be received by placing pressure sensors at the other end of the pipe or along the pipe. This allows for real-time monitoring of pipe blockages.

[0097] A fiber optic detection device 29 is installed in the main pipeline 1. Using the optical fiber 29 as a sensor, the pipeline's condition can be continuously monitored over long distances. Environmental changes around the pipeline can be detected by measuring changes in the characteristics of light propagating in the fiber. The optical fiber is laid along the oil and gas pipeline, close to the outer wall. Data on the optical fiber is periodically collected using the fiber optic sensing system, and the propagation characteristics of the light are analyzed to pinpoint the approximate location of leaks. Pipeline blockages can lead to increased pressure, causing strain or temperature changes in the pipeline wall. The fiber optic sensor can detect these changes in physical quantities, thus identifying the location of the blockage. It can detect minute environmental changes and is highly sensitive to blockage detection. The fiber optic sensor can cover long distances of pipeline, enabling remote monitoring. The pipeline condition can be monitored in real time, allowing for timely problem detection. The fiber optic system is insensitive to electromagnetic interference and is suitable for various environments. However, due to the difficulty of installation, high cost, and susceptibility to mechanical damage in actual operating conditions, the fiber optic cable is installed at bends in the pipe.

[0098] A resistivity tomography (ERT) module 30 is installed in the main pipeline 1 to reconstruct an image of the internal structure of an object by measuring the electrical impedance distribution inside the object. A high-speed camera 31 is installed near the transparent pipe section. The ERT module 30 and the high-speed camera 31 work together to monitor the deposition of fluid in the pipeline, providing a more intuitive view of the flow, deposition, and blockage of hydrates. The installation is chosen to be away from the pump end to reduce the impact of the pump and to maximize the visualization of the blockage.

[0099] The operating procedure for the above system is as follows: Check that all pipe connections are tight and leak-free. Open the manual gate valve 9 and close the second solenoid valve 10. Open the liquid supply pump 3 of the liquid injection branch, and control the inlet flow rate through the liquid flow meter 4 and the liquid flow solenoid valve 5 to inject the oil-water mixture into the pipeline to the preset liquid level. Start the circulation pump 7. Open the methane cylinder 18 of the gas injection branch, and control the methane gas injection rate through the pressure stabilizing tank 17, the pressure sensor 16, the gas flow meter 15, and the third gas flow solenoid valve 14 to maintain the required experimental pressure condition of 8 MPa. Set the ambient temperature to the typical seabed temperature of 4°C.

[0100] Under the above conditions, hydrates will form, triggering a blockage experiment. The acoustic wave transmitting device 22 is activated, and continuous or pulsed acoustic waves are transmitted as needed. The acoustic wave receiving device 23 receives the reflected acoustic wave signal, opens and closes the fifth solenoid valve 26, creating conditions for pressure wave emission. The first static pressure sensor 25, dynamic pressure sensor 27, and second static pressure sensor 28 collect reflected wave signals. The fiber optic detection device 29 is activated, along with the ERT module 30 and high-speed camera 31, to image and observe the fluid within the transparent pipe section. Temperature and pressure sensor signals are collected. The impedance distribution image of the fluid within the pipe is reconstructed using ERT imaging technology, and the dynamic changes of the fluid are recorded by the high-speed camera 31. The fluid deposition is observed, and the location and type of blockage are inferred by analyzing the arrival time of the reflected acoustic wave, the arrival time and amplitude of the reflected pressure wave signal.

[0101] After the experiment, shut off all gas and oil / water sources, open the second solenoid valve 10, and the gas flow solenoid valve 19 to discharge the waste liquid and waste gas from the pipeline.

[0102] To improve detection accuracy and reliability, the acquired signals are denoised, and features from different sensors, such as pressure wave changes and sound wave frequencies, are extracted and converted into dimensionless scalars. Standardization is then applied, mapping all features to the [0,1] interval. The blockage determination criteria are as follows:

[0103] 1. Time difference of sound wave reflection ( Threshold

[0104] Criteria for judgment:

[0105]

[0106] In the formula, L is the pipe length and c is the speed of sound. The time it takes for the sound wave to be detected without obstruction. The time it takes for a blockage to occur and for a sound wave to be detected, where, It is the time difference detected by the sensor; it is not a calculated value. This indicates the speed at which the sound wave was detected during the blockage.

[0107]

[0108] When used alone, the criteria for judgment are: A threshold is set; exceeding the threshold is considered a blockage.

[0109] 2. Pressure wave amplitude attenuation rate ( Threshold

[0110]

[0111] In the formula, The initial amplitude, This is the reflection amplitude. When used alone, the determination criteria are: The pressure wave amplitude attenuation rate threshold is used to determine if a blockage has occurred.

[0112] 3. Attenuation of fiber optic DAS flow noise intensity ( Threshold

[0113]

[0114] When used alone, the criterion is based on the noise intensity of the fluid flow within the pipe. (Unit: dB) DAS acoustic intensity characteristics, normal flow high-intensity stable noise set to When a blockage occurs, the noise intensity decreases significantly. (When completely blocked, it approaches background noise); exceeding the threshold is considered a blockage. The fiber optic DAS flow noise intensity attenuation threshold is used to determine if the fiber is blocked.

[0115] 4. Evaluation of ERT blockage section ( Threshold

[0116]

[0117] In the formula, S1 is the cross-sectional area of ​​the pipe, and S2 is the cross-sectional area of ​​the blockage. When used alone, the criterion is: the low conductivity area of ​​the cross-section. When evaluating the ERT blockage section threshold, it is determined to be blocked.

[0118] 5. Abnormal pressure difference ( Threshold

[0119]

[0120] In the formula, For normal operating pressure, The blockage is due to insufficient operating pressure. Judgment criterion: Abnormal pressure increase. A threshold value is used to determine if a blockage has occurred. In a preferred embodiment, It can be an average value.

[0121] 6. Abnormal temperature difference ( Threshold

[0122]

[0123] In the formula, For normal operating pressure, The problem stems from blocked operating pressure. Judgment criterion: Abnormal temperature increase. A blockage is identified when the abnormal temperature difference threshold is reached. In a preferred embodiment, It can be an average value.

[0124] The above-mentioned anomaly evaluation criteria are weighted and fused, assuming that the characteristic signals of different sensors are... , ... The weighted fusion is :

[0125]

[0126] It is the evaluation standard for the detection anomaly of the i-th type of sensor. These are the weights associated with each type of evaluation criterion. If The result is determined to be a blockage (this value needs to be comprehensively judged through subsequent experiments).

[0127] Based on pre-static weight allocation according to sensor characteristics, ultrasonic sensor: weight =0.5, suitable for long-distance detection; pressure wave sensor: weight =0.25, fast response but susceptible to interference; Fiber optic sensor: weight =0.1, high environmental stability; ERT sensor: weight =0.05, imaging-assisted, based on temperature and pressure data measured at each point. = =0.05, and the optimal static weight combination was determined through experimental calibration.

[0128] Then, the weights are dynamically adjusted based on real-time operating conditions. Flow velocity changes: At high flow velocities, the pressure wave signal attenuates rapidly, thus reducing its weight. ↓), increase the weight of fiber optic sensors ( ↑). Noise interference: If the acoustic sensor is contaminated by environmental noise (such as mechanical vibration), causing a sudden and significant fluctuation in signal strength, its weight should be temporarily reduced. ↓), increase the weight of the ERT sensor ( (↑).

[0129] Example of weighted fusion detection for pipe blockage: Pressure sensor shows abnormally high pressure, initially suspecting blockage; Weight adjustment: Weight of acoustic sensor. Increasing the weight to 0.5 enhances the analysis of reflected signals and pressure wave sensor weights. Maintain a value of 0.3 for rapid localization, and reduce the weights of other sensors proportionally; integrate all evaluation criteria:

[0130]

[0131] when The pipeline is blocked and requires emergency handling.

[0132] By adjusting the weights using the methods described above, multi-sensor signal fusion can be optimized in existing systems. This avoids incomplete detection by a single sensor and the limitations imposed by sensors due to specific environmental influences, significantly improving the accuracy and reliability of pipeline blockage detection. The threshold can be preferentially obtained from experimental test values ​​under non-blockage conditions. Furthermore, when multiple detection values ​​exist, the average can be used to calculate anomaly evaluation. The fused signal characteristics avoid the problem of insufficient detection by a single sensor or a single type of sensor. This pipeline and detection method utilizes traditional detection techniques while also incorporating advanced electrical resistivity tomography (ERT) technology. The aim is to leverage the mature application of these techniques in oil and gas transportation systems, as adding new detection technologies to existing pipelines is challenging. Through sensor arrays and data feature extraction and fusion, existing data is fully utilized to deeply mine useful information and better ensure flow safety.

[0133] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A circulating pipeline experimental system for multiple detection methods, characterized in that, It includes a main pipeline (1) and a pipeline blockage detection device installed on the main pipeline (1); Among them, the main pipe (1) is formed into several spiral rectangles that surround from the inside to the outside on the same plane. Each ring of the main pipe (1) includes a straight pipe and a bend that connects two straight pipes and turns them. Among them, the innermost ring pipe and the middle ring pipe of the main pipe (1) include a first vertical straight pipe and a second vertical straight pipe arranged vertically opposite each other, and a first horizontal straight pipe and a second horizontal straight pipe arranged horizontally opposite each other. Among them, the outermost straight pipe of the main pipe (1) includes a first vertical straight pipe and a second vertical straight pipe arranged vertically opposite each other, as well as a first horizontal straight pipe; Among them, the vertical straight pipes are parallel to each other, and the horizontal straight pipes are parallel to each other; The innermost horizontal straight pipe of the innermost pipe of the main pipe (1) is provided with the innermost outlet, and the outermost vertical straight pipe of the outermost pipe of the main pipe (1) is provided with the outermost inlet. Among them, the pipeline blockage detection device includes An ultrasonic sensor includes a sound wave emitting device (22), a first sound wave receiving device (231), and a second sound wave receiving device (232); The pressure wave sensor includes a first static pressure sensor (25), a dynamic pressure sensor (27), and a second static pressure sensor (28); Fiber optic sensor, including fiber optic (29) and fiber optic sensing system; ERT sensor, including an electrical resistance tomography module (30); and Pressure sensor (16) and temperature sensor.

2. The circulating pipeline experimental system for multiple detection methods according to claim 1, characterized in that, The pipe blockage detection device also includes a fourth solenoid valve (24), a fifth solenoid valve (26), and a high-speed camera (31); A sound wave emitting device (22) is installed on the second transverse straight pipe of the innermost ring of the main pipe (1); Among them, a first sound wave receiving device (231) is installed on the second horizontal straight pipe of each ring of the main pipe (1). Each first sound wave receiving device (231) is arranged in a vertical direction opposite to each other and parallel to each other, and is located upstream of the first sound wave receiving device (231). Among them, a fourth solenoid valve (24) is installed on the first vertical straight pipe of each ring of the main pipeline (1). Each fourth solenoid valve (24) is arranged in parallel and opposite to each other in the horizontal direction and is located upstream of the first sound wave receiving device (231). The fourth solenoid valve is used to simulate the leakage of the seabed pipeline. Among them, a second acoustic wave receiving device (232) is installed on the first horizontal straight pipe of each ring of the main pipe (1). Each second acoustic wave receiving device (232) is arranged in a vertical direction opposite to each other and parallel to each other, and is located upstream of the fourth solenoid valve (24); the first acoustic wave receiving device (231) and the second acoustic wave receiving device (232) are arranged in a vertical direction opposite to each other and parallel to each other. Among them, the first static pressure sensor (25), the fifth solenoid valve (26), the dynamic pressure sensor (27) and the second static pressure sensor (28) are sequentially installed on the first horizontal straight pipe of the innermost ring pipe of the main pipe (1) along the upstream direction. The first static pressure sensor (25) is located upstream of the second acoustic wave receiving device (232), and the fifth solenoid valve (26) is opened and closed to form pressure waves. Among them, optical fibers (29) are laid in each ring of the main pipe (1), and the optical fiber sensing system is set outside the main pipe (1) to receive optical fiber signals. Transparent pipe segments and resistance tomography modules (30) are installed on the first vertical straight pipe and the second vertical straight pipe of the innermost ring pipe of the main pipe (1). The transparent pipe segments are arranged relatively parallel in the horizontal direction, and the resistance tomography modules (30) are arranged relatively parallel in the horizontal direction. The high-speed camera (31) is set outside the main pipe (1), and the transparent pipe section is within the shooting field of the high-speed camera (31); The pressure sensor (16) and the temperature sensor are installed on at least one straight pipe of at least one loop of the main pipe (1).

3. The circulating pipeline experimental system for multiple detection methods according to claim 2, characterized in that, It also includes an injection branch, a connecting pipe (2), a circulating screw pump (7), a first tee (32), a drainage branch, a second tee (8), an air injection branch, an air exhaust branch, a first branch, and a third tee (12); The injection branch includes an injection branch pipeline and a storage tank (6), a supply pump (5), a liquid flow meter (4), and a first solenoid valve (3) arranged sequentially along the downstream direction on the injection branch pipeline. The first solenoid valve (3) is located at the outlet end of the injection branch pipeline. The connecting pipe (2) is set between the innermost outlet of the innermost pipe of the main pipe (1) and the outermost inlet of the outermost pipe of the main pipe (1). A circulating screw pump (7) is installed on the connecting pipe (2). The innermost outlet is the second horizontal straight pipe outlet of the innermost pipe of the main pipe (1), and the outermost inlet is the second vertical straight pipe inlet of the outermost pipe of the main pipe (1). The first inlet of the first tee (32) is connected to the outlet of the injection branch pipeline, the second inlet of the first tee (32) is connected to the outlet of the pipeline (2), and the outlet of the first tee (32) is connected to the outermost inlet of the outermost ring of the main pipeline (1). The drainage branch includes a drainage branch pipeline and a manual gate valve (9), a second solenoid valve (10), and a waste liquid collection tank (11) arranged sequentially along the downstream direction on the drainage branch pipeline. The manual gate valve (9) is located at the inlet end of the drainage branch pipeline. The inlet of the second tee (8) is connected to the outlet of the innermost ring of the innermost ring of the main pipe (1), the first outlet of the second tee (8) is connected to the inlet of the drain branch pipe, and the second outlet of the second tee (8) is connected to the outlet of the pipe (2). The gas injection branch includes a gas injection branch pipeline and a gas cylinder (18), a pressure stabilizing tank (17), a pressure sensor (16), a gas flow meter (15), a third solenoid valve (14), and a first needle valve (13) arranged sequentially along the downstream direction on the gas injection branch pipeline. The first needle valve (13) is located at the outlet end of the gas injection branch pipeline. The exhaust branch includes an exhaust branch pipe and a gas flow solenoid valve (19), a second needle valve (20) and a waste gas recovery and treatment device (21) arranged sequentially along the downstream direction on the exhaust branch pipe. The gas flow solenoid valve (19) is located at the inlet end of the exhaust branch pipe. The first branch includes the first branch pipeline, and the first port of the first branch pipeline is connected to the second transverse straight pipe upstream of the innermost outlet of the innermost pipeline of the main pipeline (1); The first valve port of the third tee (12) is connected to the second port of the first branch, the second valve port of the third tee (12) is connected to the inlet of the drain branch pipe, and the third valve port of the third tee (12) is connected to the inlet of the exhaust branch pipe.

4. The circulating pipeline experimental system for multiple detection methods according to claim 3, characterized in that, The acoustic wave emitting device (22) is installed on the second transverse straight pipe of the innermost ring of the main pipe (1) upstream of the first branch; The connecting pipe (2) includes a horizontal section and a first vertical section and a second vertical section located at both ends of the horizontal section and connected to the horizontal section. The circulating screw pump (7) is located in the horizontal section of the connecting pipe (2). The second outlet of the second tee (8) is connected to the inlet of the first vertical section of the connecting pipe (2). The second inlet of the first tee (32) is connected to the outlet of the second vertical section of the connecting pipe (2).

5. A method for detecting hydrate blockage in a circulating pipeline, characterized in that, The system described in claim 4 is used for detection; Open the manual gate valve (9) of the drainage branch and close the second solenoid valve (10); Open the first solenoid valve (3) and the supply pump (5) of the injection branch, and control the inlet flow rate through the liquid flow meter (4) and the first solenoid valve (3) to inject the oil-water mixture into the outermost inlet of the outermost ring of the main pipe (1) to the preset liquid level. Turn on the circulating screw pump (7); Open the methane cylinder (18) of the gas injection branch, and control the amount of methane gas injected through the pressure stabilizing tank (17), pressure sensor (16), gas flow meter (15) and third solenoid valve (14) to maintain the pressure conditions required for the experiment. Set the ambient temperature to the typical seabed temperature; Under the above conditions, hydrates are generated in the main pipeline (1); The sound wave transmitting device (22) is activated to send out sound waves, and the first and second sound wave receiving devices (231, 232) receive the reflected sound wave signals. The fifth solenoid valve (26) is opened and closed to emit pressure waves, and the first static pressure sensor (25), the dynamic pressure sensor (27), and the second static pressure sensor (28) collect pressure reflection wave signals. Start the fiber optic sensing system; The resistivity tomography module (30) and the high-speed camera (31) are activated to image the fluid in the transparent pipe section and acquire the signals from the temperature and pressure sensors to obtain the resistivity distribution image of the fluid in the pipe as well as the dynamic changes and deposition images of the fluid. Blockage can be inferred based on acoustic wave reflection time difference, pressure wave amplitude attenuation rate, fiber DAS flow noise intensity, ERT blockage cross-section evaluation, abnormal pressure difference, and abnormal temperature difference.

6. The method for detecting hydrate blockage in a circulating pipeline according to claim 5, characterized in that, After the experiment, close the first solenoid valve (3) and the liquid supply pump (5) of the liquid injection branch, close all gas and oil / water sources, close the circulating screw pump (7), open the second solenoid valve (10) of the liquid discharge branch and the gas flow solenoid valve (19) of the exhaust branch, and discharge the waste liquid and waste gas in the pipeline.

7. The method for detecting hydrate blockage in a circulating pipeline according to claim 6, characterized in that, The various anomaly evaluation criteria of the sensors are weighted and fused, and the blockage is inferred based on the characteristic signals after weighted fusion; Among them, the evaluation criteria for various detection anomalies of different types of sensors include Time difference of sound wave reflection from ultrasonic sensor ; Pressure wave amplitude attenuation rate derived from pressure wave sensor ; Attenuation of fiber optic DAS flow noise intensity from fiber optic sensors ; Evaluation of ERT clogging sections derived from ERT sensors ; Abnormal pressure difference originating from pressure sensor ; Abnormal temperature difference originating from temperature sensor .

8. The method for detecting hydrate blockage in a circulating pipeline according to claim 7, characterized in that, in, Evaluation criteria for various detection anomalies of sensors , ... The weighted fusion result is the characteristic signal. It is expressed by the following formula: It is the i-th type of detection anomaly evaluation standard for the sensor. is the weight corresponding to the i-th type of anomaly evaluation standard of the sensor, and N is the number of anomaly evaluation standards.

9. The method for detecting hydrate blockage in a circulating pipeline according to claim 7, characterized in that, The weights are obtained in the following way: Static weight allocation is performed based on sensor characteristics; The weights are obtained by dynamically assigning weights based on real-time operating conditions. The static weight allocation is derived from the acoustic wave reflection time difference of the ultrasonic sensor. static weights =0.5; Pressure wave amplitude attenuation rate derived from pressure wave sensor static weights =0.25; Attenuation of fiber optic DAS flow noise intensity from fiber optic sensors static weights =0.1; Evaluation of ERT clogging sections derived from ERT sensors static weights =0.05; Abnormal pressure difference originating from pressure sensor static weights =0.05; Abnormal temperature difference originating from temperature sensor static weights =0.05; Dynamic weight allocation includes Adjust the pressure wave amplitude attenuation rate from the pressure wave sensor based on flow velocity changes. static weights and the attenuation of fiber optic DAS flow noise intensity from fiber optic sensors. static weights ; And adjust the sound wave reflection time difference from the ultrasonic sensor according to noise interference. static weights And evaluation of ERT blockage cross-section derived from ERT sensors static weights .

10. The method for detecting hydrate blockage in a circulating pipeline according to claim 9, characterized in that, Adjust the pressure wave amplitude attenuation rate from the pressure wave sensor based on flow velocity changes. static weights and the attenuation of fiber optic DAS flow noise intensity from fiber optic sensors. static weights This includes the rapid attenuation of pressure wave signals when the flow rate increases, and the reduction of static weights. Increase static weights ; Among them, the sound wave reflection time difference from the ultrasonic sensor is adjusted according to noise interference. static weights And evaluation of ERT blockage cross-section derived from ERT sensors static weights This includes the impact of environmental noise on acoustic sensors, reducing static weights. Increase static weights .

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