Test system and method for in-situ monitoring of hydrate formation blockage in simulated subsea hydrocarbon pipeline

Abstract

The present application relates to the field of deepwater pipeline transportation flow safety, disclose a kind of for simulating hydrate generation blockage in situ monitoring of submarine oil and gas transportation pipeline test system and method, it includes: the inside of high-pressure container is provided with water outlet with valve and booster pump water inlet;Constant-temperature seawater is filled in the inside of groove of high-pressure container by booster pump, maintains groove inside as high-pressure water bath environment, middle is provided with multifunctional pipeline group in groove;Two ends of multifunctional pipeline group are respectively connected with the first end of first branch pipeline and the first end of second branch pipeline through flange;Second end of first branch pipeline and second end of second branch pipeline are connected into an organic whole, circulation pump is arranged on first branch pipeline, and circulation pipeline is formed;Temperature and pressure control system controls temperature in pipeline;Temperature and pressure monitoring control system is used to measure temperature and pressure in pipeline, to simulate hydrate generation blockage in situ monitoring of submarine oil and gas transportation pipeline.

Description

Technical Field

[0001] This invention relates to the field of deep-water pipeline transportation safety technology, and in particular to a test system and method for simulating in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines. It is especially suitable for in-situ monitoring of hydrate formation and blockage caused by pressure gradient changes and local pipeline leaks in deep-water pipelines. Background Technology

[0002] Deepwater oil and gas gathering and transportation systems play a crucial role in energy supply, but they also face the challenges of hydrate formation and blockage. Therefore, exploring methods for controlling hydrate risks within pipelines during transportation is essential. Deepwater areas are characterized by depth, low temperature, and high pressure. Oil and gas at the bottom of the well experience a significant temperature drop after flowing through the low-temperature seawater section, and the temperature further decreases at the wellhead due to throttling, sometimes even falling below zero degrees Celsius, easily meeting the conditions for hydrate formation. The complex layout of pipelines on the seabed, with varying pressure changes in different gradient sections, riser sections, and bends, along with pressure gradient changes over long distances, the start-up and shutdown of pipeline booster pumps, pump operating cycles, and pump output pressure adjustments, all alter the patterns of hydrate formation and blockage.

[0003] In addition, subsea pipelines are constantly exposed to high pressure and high salinity in the deep sea, which makes them prone to corrosion and damage, leading to pipeline leaks. This allows seawater to seep into the pipeline, causing hydrate formation and blockage, which is a key technical challenge that restricts the safe and efficient production of deep-sea gas wells. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this invention is to provide a testing system and method for simulating in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines, which is used to analyze the impact of pipeline pressure gradient changes, booster pump start-up and shutdown, and local leaks on hydrate formation.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a test system for simulating in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines, comprising: a high-pressure container, the inner side of which is provided with a water outlet with a valve and a booster pump water inlet; constant-temperature seawater is injected into the tank of the high-pressure container by the booster pump to maintain a high-pressure water bath environment inside the tank; a multi-functional pipeline assembly is arranged in the middle of the tank; the two ends of the multi-functional pipeline assembly are respectively connected to the first end of the first branch pipeline and the first end of the second branch pipeline via a first flange and a second flange, respectively; the second end of the first branch pipeline is connected to the second end of the second branch pipeline to form a whole; a circulation pump is arranged on the first branch pipeline to form a circulation pipeline; a temperature and pressure control system for controlling the temperature inside the pipeline; and a temperature and pressure monitoring control system for measuring the temperature and pressure inside the pipeline to simulate in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines.

[0006] Furthermore, the high-pressure vessel is a rectangular pressure vessel with a removable cover plate on the top surface, which is fixed to the tank body by bolts; the first flange and the second flange are located inside the tank body; and a sapphire viewing window is provided on the outer side of the high-pressure vessel.

[0007] Furthermore, when conducting in-situ monitoring of hydrate formation and blockage under changes in pipeline pressure gradient, the multi-functional pipeline group adopts a pressure gradient control section; a series of pressure regulating valves are distributed on the pipeline, and a spiral axial flow booster pump that cooperates with the pressure regulating valves is installed on the pressure gradient control section.

[0008] When conducting pipeline leakage tests, the multi-functional pipeline group uses a leaking pipe section with a perforated notch; an electromagnetically controlled closure device is installed on the outside of the pipe where the perforated notch is located.

[0009] Furthermore, the closure consists of a fixed end and a movable end;

[0010] The movable end is electromagnetically controlled and can directly cover the perforated notch; a rubber pad is attached to the underside of the movable end to ensure a tight fit with the perforated notch.

[0011] Furthermore, the temperature and pressure control system includes a temperature-controlled water bath and a water bath jacket; the water bath jacket is configured in two sections, which are respectively located on the outside of the first branch pipe and the second branch pipe, so that the circulating fluid in the first branch pipe and the second branch pipe is cooled by the water bath jacket, and the outside of the water bath jacket is wrapped with heat insulation cotton.

[0012] The temperature-controlled water bath is connected to the water bath jacket located outside the second end of the first branch pipe and the second end of the second branch pipe through the inlet and outlet water pipes, and the two water bath jackets are connected.

[0013] An inlet temperature sensor and an outlet temperature sensor are respectively installed on the inlet and outlet water pipes connecting the temperature-controlled water bath and the water bath jacket.

[0014] Furthermore, the temperature and pressure control system also includes an air injection port, a liquid injection port, a pressure sensor, and a high-pressure protection device installed on the first branch pipeline;

[0015] The injection port is connected to the injection pump to inject liquid into the pipeline of the first branch pipeline. A Coriolis flow meter is installed at the front end of the injection port for real-time measurement.

[0016] The gas injection port is connected to an external high-pressure gas cylinder to supply gas to the pipeline of the first branch line. A gas flow meter for gas injection measurement is installed at the front end of the gas injection port.

[0017] A pressure sensor is installed at the front end of the intersection of the gas injection port and the first branch pipeline. The internal pressure of the gas pipeline is controlled by adjusting the opening of the gas injection port valve.

[0018] A high-pressure protection device is installed at the front end of the air injection port. When the pipeline pressure is higher than the set threshold, the valve opens to release air and reduce pressure.

[0019] Furthermore, the temperature and pressure monitoring and control system includes an inlet temperature sensor, an outlet temperature sensor, and a pressure sensor in the temperature and pressure control system, as well as a first temperature and pressure sensor, a temperature and pressure sensor group, and a second temperature and pressure sensor; the first temperature and pressure sensor and the second temperature and pressure sensor are located on the first branch pipe and the second branch pipe outside the high-pressure vessel, respectively; the temperature and pressure sensor group is distributed on the multi-functional pipeline group, evenly distributed before and after the orifice or pressure regulating valve.

[0020] A test method for simulating in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines is implemented based on the aforementioned test system for simulating in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines. The method includes conducting tests for in-situ monitoring of hydrate formation and blockage under pipeline pressure gradient changes, as well as conducting tests for pipeline leakage.

[0021] Furthermore, tests were conducted to monitor in-situ hydrate formation and blockage under varying pipeline pressure gradients, including:

[0022] The fluid flow rate of a series of pressure regulating valves in the horizontal multi-functional pipeline group is controlled. Different gradient changes in long-distance transportation pipelines are simulated in the multi-functional pipeline group. The temperature and pressure changes in the pipeline are collected in real time and observed through the side viewing window of the high-pressure vessel. At this time, the high-pressure vessel is not working.

[0023] Open the gas injection port and liquid injection port, and inject a fixed amount of gas and liquid according to the experimental conditions using a gas flow meter and a Coriolis flow meter;

[0024] The circulation pump is started to fully dissolve the gas in the pipeline, and the gas and liquid phases are transported in an orderly manner in the pipeline; the temperature and pressure sensor values ​​are collected in real time, and the opening of the pressure regulating valve is adjusted to adjust the multi-functional pipeline gradient pressure distribution of the monitoring section to the target conditions.

[0025] The temperature-controlled water bath is started to cool the environment inside the pipe through the water bath jacket; after hydrates are formed, the temperature and pressure sensor group records the data and the flow changes inside the pipe are collected in real time through images;

[0026] If the start-up and shutdown of the spiral axial flow booster pump during transportation affects the flow of hydrate slurry in the pipeline and the formation of blockages, turn on the spiral axial flow booster pump.

[0027] When excessive hydrates are generated and blockage occurs in the pipeline, close the air injection port, stop the circulation pump, turn off the spiral axial flow booster pump, and open the high-pressure protection device to release pressure and vent air, thus breaking down the hydrate blockage section.

[0028] Furthermore, tests for pipe leaks are conducted, including:

[0029] Close the electromagnetic control seal, drain the water from the high-pressure container, assemble the leaking section of the multi-functional pipeline group, use a vacuum pump to connect the outlet to discharge the air from the high-pressure container, and pump constant temperature seawater into the container through a booster pump until the pressure inside the high-pressure container reaches the set standard and maintains a stable pressure.

[0030] Open the gas injection port and liquid injection port, and inject a fixed amount of gas and liquid according to the experimental conditions using a gas flow meter and a Coriolis flow meter;

[0031] The circulation pump is started to fully dissolve the gas in the pipeline, and the gas and liquid phases are transported in an orderly manner in the pipeline; the temperature and pressure sensor group values ​​are collected in real time, the temperature-controlled water bath is turned on, and the water bath jacket is used for cooling; the value of the first temperature and pressure sensor is observed, and when the set gas transport temperature and pressure are reached, the closure is controlled to close and the orifice opening is opened.

[0032] When excessive hydrates are generated, the pipeline becomes severely blocked, and the pipeline pressure approaches the set limit pressure, the high-pressure protection device opens, the gas injection port closes completely, the electromagnetic sealer closes, the perforated gap is sealed to prevent a large amount of water from entering the gas pipeline, and the gas inside the pipeline is released into the air cylinder; the booster pump closes and the water outlet opens to remove the water accumulated inside the high-pressure container.

[0033] The present invention has the following advantages due to the adoption of the above technical solutions:

[0034] 1. This invention can simulate the temperature and pressure conditions during deep-sea pipeline transportation using a high-pressure vessel and a water bath unit. It can more accurately predict the conditions and processes of hydrate formation, monitor the formation and deposition of hydrates in the subsea pipeline in real time, as well as the slurry transportation status, thereby providing a scientific basis for the prevention and control of hydrate blockage and reducing the cost of field experiments.

[0035] 2. This invention's multifunctional pipeline assembly can test pipeline hydrate formation and blockage caused by different pipeline pressure gradients and leakage orifice diameters. It allows for the study of key factors such as hydrate growth rate and hydrate quantity under different conditions, thereby optimizing measures to prevent and repair hydrate blockage, reducing production interruptions and maintenance costs caused by hydrate blockage, while also lowering environmental risks and improving the safety and reliability of subsea oil and gas pipelines. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall structure of the test system used for in-situ monitoring of hydrate formation and blockage in submarine oil and gas pipelines in an embodiment of the present invention.

[0037] Figure 2 This is a schematic diagram of the leaking pipe section inside the high-pressure tank in an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the pressure gradient control pipe section in an embodiment of the present invention;

[0039] Figure label:

[0040] 1 Temperature-controlled water bath, 2 Water bath jacket, 3 Circulation pump, 4 First branch pipeline, 5 Gas injection port, 6 Pressure sensor, 7 High-pressure vessel, 8 Booster pump, 9 Water outlet, 10 Liquid injection port, 11 Gas flow meter, 12 Second branch pipeline, 13 First flange, 14 Electromagnetic sealer, 15 Hole notch, 16 Multifunctional pipe assembly, 17 Second flange, 18 Fixed end, 19 Movable end, 20 Water outlet temperature sensor, 21 Water inlet temperature sensor, 22 First temperature and pressure sensor, 23 Temperature and pressure sensor assembly, 24 Second temperature and pressure sensor, 25 High-pressure protection device, 26 Pressure regulating valve, 27 Coriolis flow meter, 28 Spiral axial flow booster pump. Detailed Implementation

[0041] To effectively simulate in-situ monitoring of hydrate formation under conditions such as pressure gradient changes in different gradient sections, riser sections, and bend sections of pipelines, start-up and shutdown of pipeline booster pumps, and local pipeline leaks, this invention proposes a test system and method for simulating in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines. This system is used to analyze the impact of pipeline pressure gradient changes, booster pump start-up and shutdown, and local leaks on hydrate formation, thereby improving the safety and reliability of subsea oil and gas pipelines.

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0043] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0044] Example 1: In this embodiment of the invention, a test system for in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines is provided. In this embodiment, as... Figure 1 As shown, the system includes:

[0045] The high-pressure vessel 7 has an outlet 9 with a valve and a booster pump inlet 8 on its inner side. The booster pump 8 fills the tank of the high-pressure vessel 7 with 4°C constant temperature seawater to maintain a high-pressure water bath environment inside the tank. A multi-functional pipeline group 16 is installed in the middle of the tank.

[0046] The two ends of the multi-functional pipeline assembly 16 are connected to the first end of the first branch pipeline 4 and the first end of the second branch pipeline 12 via the first flange 13 and the second flange 17, respectively; the second end of the first branch pipeline 4 is connected to the second end of the second branch pipeline 12 to form a whole; a circulation pump 3 is installed on the first branch pipeline 4 to drive the flow of mixed fluid inside the pipeline to form a circulation pipeline.

[0047] Temperature and pressure control system, used to control the temperature inside the pipeline;

[0048] The temperature and pressure monitoring and control system is used to measure the temperature and pressure inside the pipeline to simulate in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines.

[0049] In the above embodiment, the high-pressure vessel 7 is a rectangular pressure vessel with a removable cover plate on the top surface, which is fixed to the high-pressure tank body by bolts. The first flange 13 and the second flange 17 are located inside the high-pressure tank body. The multi-functional pipeline assembly 16 can be replaced by opening the cover plate and removing the flanges.

[0050] The high-pressure vessel 7 has a visual sapphire window on its outer surface, which facilitates visual monitoring in the laboratory.

[0051] In this embodiment, the multi-functional piping assembly 16 can be replaced according to the testing function. Specifically:

[0052] like Figure 3 As shown, a pressure gradient control section is used for in-situ monitoring of hydrate formation and blockage under varying pipeline pressure gradients. A series of pressure regulating valves 26 are distributed along the pipeline to precisely control fluid flow parameters, simulating the pressure change trends within the pipeline caused by different deep-water long-distance pipeline layouts, and monitoring the changes in hydrate formation and blockage patterns caused by pressure gradient changes within the horizontal pipeline during transport. Simultaneously, a spiral axial flow booster pump 28 installed on the pressure gradient control section of the multi-functional pipeline assembly 16, in conjunction with the pressure regulating valves 26, enables in-situ monitoring of hydrate formation and blockage caused by pump start-up and shutdown, pump operating cycle, and pressure fluctuations resulting from changes in pump output pressure. Both the pressure regulating valves 26 and the spiral axial flow booster pump 28 are controlled by a CNC system.

[0053] like Figure 2As shown, during the pipeline leakage test experiment, the multi-functional pipeline group 16 uses a leaking pipe section with a perforated notch 15. An electromagnetically controlled closure device 14 is installed on the outside of the pipeline where the perforated notch 15 is located to control pipeline leakage, so as to simulate the situation of pipeline leakage caused by long-term scouring and corrosion under deep water and high pressure environment, and to monitor the formation and blockage of hydrates in situ.

[0054] The sealing device 14 consists of a fixed end 18 and a movable end 19. The movable end 19 is electromagnetically controlled; when electromagnetically activated, it can directly cover the perforated notch 15 to prevent liquid from seeping into the pipe in a high-pressure seawater environment. A rubber gasket is attached to the underside of the movable end 19 to ensure a tight fit with the perforated notch 15, achieving high-pressure sealing.

[0055] Optionally, the perforated notch 15 can be made in any size and can be located at any position on the multi-functional piping assembly 16. During testing, the pipes of the multi-functional piping assembly 16 can be replaced as needed to investigate the effect of gaps with different leakage sizes.

[0056] In the above embodiments, such as Figure 1 As shown, the temperature and pressure control system includes a temperature-controlled water bath 1 and a water bath jacket 2. The water bath jacket 2 is configured in two sections, respectively located outside the first branch pipe 4 and the second branch pipe 12, so that the circulating fluid in the first branch pipe 4 and the second branch pipe 12 is cooled by the water bath jacket 2. The outside of the water bath jacket 2 is wrapped with thermal insulation cotton. The temperature-controlled water bath 1 is connected to the water bath jacket 2 located outside the second end of the first branch pipe 4 and the second end of the second branch pipe 12 via inlet and outlet water pipes, thus connecting the two sections of the water bath jacket 2.

[0057] An inlet temperature sensor 20 and an outlet temperature sensor 21 are respectively installed on the inlet and outlet water pipes connecting the temperature-controlled water bath 1 and the water bath jacket 2.

[0058] During use, the interior of the water bath jacket 2 is a normal pressure water bath environment. The first branch pipe 4 and the second branch pipe 12 exchange heat with the low temperature water in the water bath jacket 2 to cool the fluid in the pipe and achieve temperature control in the circulation pipeline.

[0059] In this embodiment, the temperature and pressure control system further includes an air injection port 5, a liquid injection port 10, a pressure sensor 6, and a high-pressure protection device 25 installed on the first branch pipe 4. The liquid injection port 10 is connected to a liquid injection pump to inject liquid into the pipeline of the first branch pipe 4. A Coriolis flow meter 27 is installed at the front end of the liquid injection port 10 for real-time measurement. The air injection port 5 is connected to an external high-pressure gas cylinder to supply gas into the pipeline of the first branch pipe 4. A gas flow meter 11 for gas injection measurement is installed at the front end of the air injection port 5. A pressure sensor 6 is installed at the front end of the intersection of the air injection port 5 and the first branch pipe 4. The pressure inside the gas pipeline is controlled by adjusting the opening degree of the valve at the air injection port 5. A high-pressure protection device 25 is installed at the front end of the air injection port 5. When the pipeline pressure exceeds a set threshold, the valve opens to release gas and reduce pressure.

[0060] In the above embodiments, the temperature and pressure monitoring and control system includes, in addition to the inlet temperature sensor 20, the outlet temperature sensor 21, and the pressure sensor 6, a first temperature and pressure sensor 22, a temperature and pressure sensor group 23, and a second temperature and pressure sensor 24. The first temperature and pressure sensor 22 and the second temperature and pressure sensor 24 are located on the first branch pipe 4 and the second branch pipe 12 outside the high-pressure vessel 7, respectively; the temperature and pressure sensor group 23 is distributed on the multi-functional pipeline group 16, evenly distributed before and after the orifice notch 15 or the pressure regulating valve 26.

[0061] The temperature and pressure sensors are located inside the pipe and are in direct contact with the fluid, measuring the temperature and pressure inside the pipe.

[0062] In the above embodiment, a circulation pump 3, a high-pressure protection device 25, an air injection port 5, a pressure sensor 6, a liquid injection port 10, and a first temperature and pressure sensor 22 are installed sequentially on the first branch pipeline 4 in accordance with the fluid flow direction.

[0063] In the above embodiments, optionally, the temperature and pressure sensor group 23 is placed on the multifunctional pipe group 16 at a distance of 1 to 2 m / group to obtain sufficient pressure and temperature data.

[0064] In the above embodiments, optionally, the pressure regulating valves 26 are placed on the multi-functional pipeline group 16 at a distance of 2m to 3m each, so as to fully simulate complex pressure changes.

[0065] In the above embodiments, optionally, the portions of the first branch pipe 4 and the second branch pipe 12 exposed to air are wrapped with thermal insulation cotton to reduce the impact of room temperature on the gas inside the pipes.

[0066] In the above embodiments, optionally, the leaking pipe section material of the first branch pipe 4, the second branch pipe 12, and the multi-functional pipe group 16 is preferably carbon steel of API 5L X56 or higher grade.

[0067] Example 2: In this embodiment of the invention, a test method for simulating in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines is provided. The test method includes: conducting in-situ monitoring of hydrate formation and blockage under pipeline pressure gradient changes, and conducting pipeline leakage tests.

[0068] In this embodiment, when conducting in-situ monitoring of hydrate formation and blockage under pipeline pressure gradient changes, the testing method includes the following steps:

[0069] 101) Control the fluid flow of a series of pressure regulating valves 26 in the horizontal multi-functional pipeline group 16, simulate different gradient changes in long-distance transportation pipelines in the multi-functional pipeline group 16, collect temperature and pressure changes in the pipeline in real time, and observe them through the side viewing window of the high-pressure vessel 7. At this time, the high-pressure vessel 7 is not working.

[0070] 102) Open the gas injection port 5 and the liquid injection port 10, and inject a fixed amount of gas and liquid according to the experimental conditions, using the gas flow meter 11 and the Coriolis flow meter 27.

[0071] 103) Start the circulation pump 3 to fully dissolve the gas in the pipeline, allowing the gas and liquid phases to be transported in an orderly manner within the pipeline. Real-time data acquisition of temperature and pressure sensor group 23 and adjustment of pressure regulating valve 26 are performed to adjust the multi-functional pipeline gradient pressure distribution in the monitoring section to the target conditions.

[0072] The pressure regulating valve can be tested within a range of 0-10 MPa, allowing for both short-distance, small-scale staged pressure fluctuation simulation experiments and experiments under conditions of sudden pressure drop.

[0073] 104) Start the temperature-controlled water bath 1 to cool the environment inside the pipe through the water bath jacket 2. After hydrates are formed, the temperature and pressure sensor group 23 records the data and collects the changes in the flow inside the pipe in real time through images.

[0074] 105) If the start and stop of the spiral axial flow booster pump 28 during the transportation process affects the flow of hydrate slurry in the pipeline and the formation of blockages, turn on the spiral axial flow booster pump 28. The specific parameters can be set according to the experimental conditions.

[0075] 106) When excessive hydrates are generated and blockage occurs in the pipeline, close the air injection port 5, stop the circulation pump 3, turn off the spiral axial flow booster pump 28, and open the high pressure protection device 25 to release pressure and vent air, thus decomposing the hydrate blockage section.

[0076] In this embodiment, the test method for simulating local pipeline leakage includes the following steps:

[0077] 201) Close the electromagnetic control seal 14, drain the water from the high-pressure container 7, and assemble the leaking pipe section of the multi-functional pipeline group 16. After installation, use a vacuum pump connected to the outlet 9 to purge the air from the high-pressure container 7, and use a booster pump 8 to pump 4℃ constant temperature seawater into the container until the internal pressure of the high-pressure container 7 reaches the set standard and remains stable.

[0078] 202) Open the gas injection port 5 and the liquid injection port 10, and inject a fixed amount of gas and liquid according to the experimental conditions, using the gas flow meter 11 and the Coriolis flow meter 27.

[0079] 203) Start the circulation pump 3 to fully dissolve the gas in the pipeline, allowing the gas and liquid phases to be transported in an orderly manner within the pipeline. Real-time data are collected from the temperature and pressure sensor group 23, and the temperature-controlled water bath 1 is turned on to cool the gas using the water bath jacket 2. The data from the first temperature and pressure sensor 22 are observed. When the set gas transport temperature and pressure are reached, the control valve 14 is closed and the perforated notch 15 is opened.

[0080] 204) When excessive hydrate is generated, the pipeline becomes severely blocked, and the pipeline pressure approaches the set limit pressure, the high-pressure protection device 25 opens, the air inlet 5 closes completely, the electromagnetic sealer 14 closes, the perforated notch 15 is sealed to prevent a large amount of water from entering the gas pipeline, and the gas inside the pipeline is released into the air bottle. The booster pump 8 closes, the outlet 9 opens, and the water accumulated inside the high-pressure container 7 is drained.

[0081] In the above embodiments, optionally, the refrigerant used between the water bath 2 and the temperature-controlled water bath 1 is a 30% volume fraction ethylene glycol aqueous solution.

[0082] In the above embodiments, optionally, the detection points of the temperature and pressure sensors are all located inside the pipe, directly measuring the temperature and pressure inside the pipe.

[0083] In the above embodiments, optionally, the interior of the high-pressure container 7 is filled with seawater at a constant temperature of 4°C to simulate the temperature of deep-sea water.

[0084] In the above embodiments, optionally, the visible area of ​​the pressure gradient control section of the multifunctional piping assembly 16 uses polymethyl methacrylate as the visible section material, and the matching pressure regulating valve 26 and spiral axial flow booster pump 28 are connected through stainless steel flanges, with a working pressure of 0-8 MPa. The leakage section of the multifunctional piping assembly 16 uses stainless steel pressure-resistant material, which can achieve a pressure resistance of 30 MPa.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A testing system for in-situ monitoring of hydrate formation and blockage in simulated subsea oil and gas pipelines, characterized in that, include: The high-pressure container (7) has a water outlet (9) with a valve and a booster pump water inlet (8) on its inner side; constant temperature seawater is injected into the tank of the high-pressure container (7) through the booster pump (8) to maintain the tank as a high-pressure water bath environment; a multi-functional pipeline group (16) is set in the middle of the tank. The two ends of the multi-functional pipeline assembly (16) are connected to the first end of the first branch pipeline (4) and the first end of the second branch pipeline (12) via the first flange (13) and the second flange (17) respectively; the second end of the first branch pipeline (4) is connected to the second end of the second branch pipeline (12) to form a whole; a circulation pump (3) is installed on the first branch pipeline (4) to form a circulation pipeline; Temperature and pressure control system, used to control the temperature inside the pipeline; Temperature and pressure monitoring and control system is used to measure the temperature and pressure inside the pipeline to simulate in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines; The high-pressure vessel (7) is a rectangular pressure vessel with a removable cover plate on the top surface, which is fixed to the tank body by bolts; the first flange (13) and the second flange (17) are located inside the tank body; the outer side of the high-pressure vessel (7) is provided with a visual sapphire window; When conducting in-situ monitoring of hydrate formation and blockage under pipeline pressure gradient changes, the multi-functional pipeline group (16) adopts a pressure gradient control section; a series of pressure regulating valves (26) are distributed on the pipeline, and a spiral axial flow booster pump (28) that cooperates with the pressure regulating valves (26) is installed on the pressure gradient control section. When conducting pipeline leakage test experiments, the multi-functional pipeline group (16) uses a leaking pipe section with a perforated notch (15); an electromagnetically controlled closure device (14) is installed on the outside of the pipeline where the perforated notch (15) is located. The closure (14) consists of a fixed end (18) and a movable end (19); The movable end (19) is electromagnetically controlled and can directly cover the perforated notch (15); a rubber pad is attached to the underside of the movable end (19) to ensure a tight fit with the perforated notch (15).

2. The test system for in-situ monitoring of hydrate formation and blockage in simulated subsea oil and gas pipelines as described in claim 1, characterized in that, The temperature and pressure control system includes a temperature-controlled water bath (1) and a water bath jacket (2); the water bath jacket (2) is set in two sections, which are respectively set outside the first branch pipe (4) and the second branch pipe (12) so that the circulating fluid in the first branch pipe (4) and the second branch pipe (12) is cooled by the water bath jacket (2), and the outside of the water bath jacket (2) is wrapped with heat insulation cotton; The temperature-controlled water bath (1) is connected to the water bath jacket (2) located outside the second end of the first branch pipe (4) and the second end of the second branch pipe (12) through the inlet and outlet water pipes, and the two sections of the water bath jacket (2) are connected. An inlet temperature sensor (20) and an outlet temperature sensor (21) are respectively installed on the inlet and outlet water pipes connecting the temperature-controlled water bath (1) and the water bath jacket (2).

3. The test system for in-situ monitoring of hydrate formation and blockage in simulated subsea oil and gas pipelines as described in claim 2, characterized in that, The temperature and pressure control system also includes an air injection port (5), a liquid injection port (10), a pressure sensor (6), and a high-pressure protection device (25) installed on the first branch pipeline (4). The injection port (10) is connected to the injection pump to inject liquid into the pipeline of the first branch pipeline (4). A Coriolis flow meter (27) is installed at the front end of the injection port (10) for real-time measurement. The gas injection port (5) is connected to an external high-pressure gas cylinder to supply gas to the pipeline of the first branch pipeline (4). A gas flow meter (11) for gas injection measurement is provided at the front end of the gas injection port (5). A pressure sensor (6) is installed at the front end of the intersection of the gas injection port (5) and the first branch pipe (4). The internal pressure of the gas pipeline is controlled by adjusting the valve opening of the gas injection port (5). A high-pressure protection device (25) is installed at the front end of the air injection port (5). When the pipeline pressure is higher than the set threshold, the valve opens to release air and reduce pressure.

4. The test system for in-situ monitoring of hydrate formation and blockage in simulated subsea oil and gas pipelines as described in claim 1, characterized in that, The temperature and pressure monitoring and control system includes an inlet temperature sensor (20), an outlet temperature sensor (21), and a pressure sensor (6) in the temperature and pressure control system, as well as a first temperature and pressure sensor (22), a temperature and pressure sensor group (23), and a second temperature and pressure sensor (24); the first temperature and pressure sensor (22) and the second temperature and pressure sensor (24) are located on the first branch pipe (4) and the second branch pipe (12) outside the high pressure vessel (7), respectively; the temperature and pressure sensor group (23) is distributed on the multi-functional pipeline group (16), and is evenly distributed before and after the orifice notch (15) or the pressure regulating valve (26).

5. A test method for simulating in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines, implemented based on the test system for simulating in-situ monitoring of hydrate formation and blockage in subsea oil and gas pipelines as described in any one of claims 1 to 4, characterized in that, This includes testing for in-situ monitoring of hydrate formation and blockage under varying pipeline pressure gradients, as well as testing for pipeline leaks.

6. The test method for in-situ monitoring of hydrate formation and blockage in simulated subsea oil and gas pipelines as described in claim 5, characterized in that, Tests were conducted to monitor in-situ hydrate formation and blockage under varying pipeline pressure gradients, including: The fluid flow rate of a series of pressure regulating valves (26) in the horizontal multi-functional pipeline group (16) is controlled. Different gradient changes of long-distance transportation pipeline are simulated in the multi-functional pipeline group (16). The temperature and pressure changes in the pipeline are collected in real time and observed through the side window of the high-pressure container (7). At this time, the high-pressure container (7) is not working. Open the gas inlet (5) and liquid inlet (10), and inject a fixed amount of gas and liquid according to the experimental conditions, using the gas flow meter (11) and Coriolis flow meter (27); Start the circulation pump (3) to fully dissolve the gas in the pipeline and transport the gas and liquid phases in an orderly manner in the pipeline; collect the values ​​of the temperature and pressure sensor group (23) in real time, adjust the opening of the pressure regulating valve (26), and adjust the multi-functional pipeline gradient pressure distribution of the monitoring section to the target conditions. Start the temperature-controlled water bath (1) and cool the environment inside the pipe through the water bath jacket (2); after the hydrate is generated, record the data through the temperature and pressure sensor group (23) and collect the changes in the flow inside the pipe in real time through the image; If the start-up and shutdown of the spiral axial flow booster pump (28) during the transportation process affects the flow of hydrate slurry in the pipeline and the generation of blockages, turn on the spiral axial flow booster pump (28). When excessive hydrates are generated and blockage occurs in the pipeline, close the air injection port (5), stop the circulation pump (3), close the spiral axial flow booster pump (28), open the high pressure protection device (25) to release pressure and vent air, and decompose the hydrate blockage section.

7. The test method for in-situ monitoring of hydrate formation and blockage in simulated subsea oil and gas pipelines as described in claim 5, characterized in that, Conducting pipeline leak tests includes: Close the electromagnetic control closure (14), drain the water in the high pressure container (7), assemble the leaking pipe section of the multi-functional pipeline group (16), use the vacuum pump to connect the outlet (9) to discharge the air in the high pressure container (7), and pump the constant temperature seawater into the container through the booster pump (8) until the pressure inside the high pressure container (7) reaches the set standard and maintains the pressure stability. Open the gas inlet (5) and liquid inlet (10), and inject a fixed amount of gas and liquid according to the experimental conditions, using the gas flow meter (11) and Coriolis flow meter (27); Start the circulation pump (3) to fully dissolve the gas in the pipeline, and transport the gas and liquid phases in an orderly manner in the pipeline; collect the values ​​of the temperature and pressure sensor group (23) in real time, turn on the temperature-controlled water bath (1), and use the water bath jacket (2) to cool down; observe the value of the first temperature and pressure sensor (22), and when the set gas transport temperature and pressure are reached, control the closure (14) to close and the perforated notch (15) to open; When excessive hydrate is generated, the pipeline is severely blocked, and the pipeline pressure approaches the set limit pressure, the high pressure protection device (25) is opened, the gas injection port (5) is completely closed, the electromagnetic sealer (14) is closed, the hole-shaped gap (15) is sealed to prevent a large amount of water from entering the gas pipeline, and the gas inside the pipeline is released into the air bottle; the booster pump (8) is closed, the water outlet (9) is opened, and the water accumulated inside the high pressure container (7) is discharged.

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