Device and method for measuring liquid carrying and flow law at variable diameter of offshore coiled tubing

Abstract

The application discloses a device and a method for measuring liquid carrying and flow law at a variable-diameter part of offshore coiled tubing. The device for measuring liquid carrying and flow law at the variable-diameter part of offshore coiled tubing is integrally provided with a gas-water mixing system, an experimental pipeline and a parameter measuring system, and a gas-liquid two-phase flow test platform is constructed, which can accurately simulate the variable-diameter working condition of offshore coiled tubing, stably circulate the experiment, and accurately collect parameters, and effectively overcomes the defects of traditional measuring devices, such as being mainly for uniform-diameter pipelines, distorted working condition simulation, unstable medium supply and rough parameter collection. The device for measuring liquid carrying and flow law at the variable-diameter part of offshore coiled tubing is provided with a gas supply structure communicated between a gas compressor and a gas storage tank, and a water supply structure matched between a water tank and a centrifugal pump, and independently stable gas and liquid conveying branches are formed, two kinds of media are concentrated and merged into a gas-water mixing section to realize full miscibility, and the gas-water miscible flow state of fluid in a wellbore of a gas well at sea before entering the variable-diameter structure can be truly restored.

Description

Technical Field

[0001] This invention relates to the field of offshore gas well drainage and gas production technology, and in particular to a device and method for measuring the liquid carrying and flow characteristics at the diameter change of offshore coiled tubing. Background Technology

[0002] Velocity tubing drainage for gas production is a crucial method for addressing liquid accumulation in offshore gas wells. However, the "convex-concave structure" formed by the coiled tubing end and existing tubing easily leads to liquid buildup, affecting drainage efficiency. Existing measurement devices are mostly designed for uniform-diameter pipes or single-structure conditions, primarily studying the influence of flow pattern characteristics or single factors on liquid-carrying capacity. They struggle to realistically simulate the complex flow under variable-diameter structures in gas well production and cannot fully reflect the liquid accumulation at the diameter change and the liquid-carrying behavior under the coupling effects of multiple factors. Current research does not comprehensively consider the combined effects of pipe diameter combinations, well inclination, and gas-liquid flow rates, and it is difficult to conduct segmented observations of pressure and flow patterns at the diameter change, failing to provide reliable experimental support for optimizing offshore velocity tubing processes. There is an urgent need to develop a variable-diameter pipe gas-liquid two-phase flow measurement device and method that is adaptable to multiple operating conditions and can accurately measure these flows. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a device and method for measuring the liquid carrying and flow characteristics at the diameter change of a marine continuous tubing.

[0004] The technical solution adopted by the present invention to solve its technical problem is: to construct a device for measuring the liquid carrying and flow law at the diameter change of a marine continuous tubing, which includes a gas-water mixing system, an experimental pipeline and a parameter measurement system; The gas-water mixing system includes a water tank, a centrifugal pump, a gas compressor, a gas storage tank, and a gas-water mixing section. The gas compressor's outlet is connected to the gas storage tank's inlet via a pipeline. The gas storage tank's outlet is connected to the gas input end of the gas-water mixing section via a pipeline. The water tank's outlet is connected to the centrifugal pump's inlet via a pipeline. The centrifugal pump's outlet is connected to the liquid input end of the gas-water mixing section via a pipeline. The experimental pipeline includes a variable diameter connecting section, a large diameter pipe section, and a small diameter pipe section connected in sequence. The input end of the large diameter pipe section is connected to the output end of the gas-water mixing section through the variable diameter connecting section. The small diameter pipe section is fitted inside the large diameter pipe section by a retaining spring. The output end of the small diameter pipe section is connected to the water tank through a return pipe. The parameter measurement system includes a gas flow meter, a liquid flow meter, and a pressure sensor. The gas flow meter is installed on the gas delivery pipeline between the gas storage tank and the gas-water mixing section. The liquid flow meter is installed on the liquid delivery pipeline between the centrifugal pump and the gas-water mixing section. The pressure sensors are distributed and installed on the experimental pipeline.

[0005] In some embodiments, the gas-water mixing system further includes multiple sets of regulating valves, which are respectively installed between the gas compressor and the gas storage tank, between the gas storage tank and the gas-water mixing section, and on the delivery pipeline between the centrifugal pump and the gas-water mixing section.

[0006] In some embodiments, the measuring device further includes an angle adjustment assembly, which includes an adjustable bracket, and the experimental tubing is mounted on the adjustable bracket.

[0007] In some embodiments, the measuring device further includes a flexible connecting hose, through which the gas-water mixing section and the variable diameter connecting section are connected.

[0008] In some embodiments, the measuring device further includes a visualization observation system, which includes a high-speed camera, and the high-speed camera is deployed corresponding to the large-diameter pipe section, the variable-diameter connecting section, and the small-diameter pipe section.

[0009] In some embodiments, the measuring device further includes a data measurement and control system, which includes a paperless recorder and a data analysis terminal; The paperless recorder is electrically connected to the gas flow meter, the liquid flow meter, and the pressure sensor, respectively. The data analysis terminal is communicatively connected to the paperless recorder.

[0010] In some embodiments, multiple pressure sensors are provided, and the multiple pressure sensors are respectively installed at both ends of the large-diameter pipe section, on the variable-diameter connecting section, and at both ends of the small-diameter pipe section.

[0011] In some embodiments, the large-diameter pipe section, the variable-diameter connecting section, and the small-diameter pipe section are all made of transparent plexiglass.

[0012] In this embodiment, a measurement method for a device for measuring the liquid carrying and flow characteristics at a change in diameter of a marine coiled tubing is also constructed. Based on the aforementioned device, the method includes the following steps: S1. Check the connection integrity of the gas-water mixing system, experimental pipelines, parameter measurement system and visualization observation system, debug the operating status of each device, and calibrate the measurement accuracy of flow meters and pressure sensors; S2. Set the experimental variable diameter combination parameters, adjust the tilt angle of the experimental pipeline through the adjustable bracket, and replace the large-diameter pipe section and small-diameter pipe section with the corresponding pipe diameter specifications. S3. Start the gas compressor and centrifugal pump to deliver gaseous and liquid media to the gas-water mixing section respectively. Adjust the gas-liquid delivery flow rate through the regulating valve to obtain the gas-water two-phase mixed medium under the preset working conditions. S4. Real-time gas and liquid flow parameters are collected by gas flow meter and liquid flow meter. Pipeline pressure and pressure drop parameters are collected in sections by each pressure sensor. At the same time, the gas and liquid flow pattern and liquid accumulation and liquid-carrying flow state in the variable diameter pipe are captured and recorded by high-speed camera. S5. Store all experimental data using a paperless recorder, organize experimental parameters using a data analysis terminal, and combine with visualized flow pattern images to analyze the gas-liquid two-phase flow characteristics and liquid carrying behavior in variable diameter pipes under different pipe diameter combinations, different well inclinations, and different gas-liquid flow rate coupling effects.

[0013] In some embodiments, the experimental diameter combination parameters include pipe diameter parameters, pipe space inclination angle parameters, diameter change boundary operation coupling parameters, and small pipe internal assembly parameters.

[0014] The present invention offers the following advantages: This device for measuring the liquid carrying capacity and flow characteristics at the diameter change point of offshore coiled tubing integrates a gas-water mixing system, experimental pipelines, and a parameter measurement system. It constructs a gas-liquid two-phase flow testing platform capable of accurately simulating the operating conditions of offshore coiled tubing at diameter changes, conducting stable cyclic experiments, and acquiring precise parameters. This effectively overcomes the shortcomings of traditional measurement devices, which are often designed for uniform-diameter pipes, suffer from distorted operating condition simulations, unstable medium supply, and coarse parameter acquisition. The device utilizes a gas supply structure connecting a gas compressor and a gas storage tank, along with a water supply structure matching a water tank and a centrifugal pump. These form independent and stable gas and liquid transport branches, respectively. The two media converge into the gas-water mixing section to achieve full mixing, realistically reproducing the gas-water mixed-phase flow state of the fluid in the offshore gas wellbore before entering the diameter change structure. Attached Figure Description

[0015] To more clearly illustrate the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the device for measuring the liquid carrying and flow patterns at the diameter change of a marine continuous tubing in some embodiments of the present invention. Detailed Implementation

[0016] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or element referred to must have a specific orientation; therefore, they should not be construed as limitations on this invention.

[0017] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0018] Please see Figure 1This invention relates to a device for measuring the liquid carrying and flow characteristics at the diameter change point of a marine continuous tubing, as described in some embodiments of the present invention. The device includes a gas-water mixing system, experimental piping, and a parameter measurement system. The gas-water mixing system includes a water tank 25, a centrifugal pump 26, a gas compressor 1, a gas storage tank 4, and a gas-water mixing section 8. The outlet of the gas compressor 1 is connected to the inlet of the gas storage tank 4 via a pipeline. The outlet of the gas storage tank 4 is connected to the gas input of the gas-water mixing section 8 via a pipeline. The outlet of the water tank 25 is connected to the inlet of the centrifugal pump 26 via a pipeline. The outlet of the centrifugal pump 26 is connected to the liquid input of the gas-water mixing section 8 via a pipeline. The experimental pipeline includes a variable-diameter connecting section 11, a large-diameter pipe section 12, and a small-diameter pipe section 14 connected in sequence. The input end of the large-diameter pipe section 12 is connected to the output end of the gas-water mixing section 8 through the variable-diameter connecting section 11. The small-diameter pipe section 14 is fitted inside the large-diameter pipe section 12 by a retaining ring. The output end of the small-diameter pipe section 14 is connected to the water tank 25 through a return pipe. The parameter measurement system includes a gas flow meter 7, a liquid flow meter 5, and pressure sensors. The gas flow meter 7 is installed on the gas delivery pipeline between the gas storage tank 4 and the gas-water mixing section 8. The liquid flow meter 5 is installed on the liquid delivery pipeline between the centrifugal pump 26 and the gas-water mixing section 8. The pressure sensors are distributed throughout the experimental pipeline.

[0019] The experimental medium for measuring the liquid carrying and flow characteristics at the diameter change point of the offshore coiled tubing is air and water. Water is supplied by centrifugal pump 26, and gas is supplied by gas compressor 1. Gas and water enter the gas-water mixing section 8 through gas and liquid flow meters. The gas-water mixing section 8 is designed based on the principle that the liquid in the oilfield is in a gas-water mixed state before being carried out of the wellhead by gas. Gas and water flow through the gas-water mixing section 8, through the large-diameter pipe section 12 and the small-diameter pipe section 14, and finally into the water tank 25. The water is then pumped back into the gas-water mixing section 8 by centrifugal pump 26, forming a complete experimental loop.

[0020] Understandably, this device for measuring the liquid carrying and flow patterns at the diameter change of offshore coiled tubing, through the integrated gas-water mixing system, experimental pipeline, and parameter measurement system, constructs a gas-liquid two-phase flow testing platform that can accurately simulate the working conditions of offshore coiled tubing at diameter change, conduct stable cyclic experiments, and accurately acquire parameters. It effectively overcomes the shortcomings of traditional measurement devices, which are mostly designed for uniform diameter pipes, have distorted working condition simulations, unstable medium supply, and coarse parameter acquisition. The device for measuring the liquid carrying and flow characteristics at the diameter change of the offshore coiled tubing uses a gas supply structure connected to a gas compressor 1 and a gas storage tank 4, and a water supply structure matched with a water tank 25 and a centrifugal pump 26, to form independent and stable gas and liquid transport branches. The two media converge into the gas-water mixing section 8 to achieve full phase mixing, which can realistically reproduce the gas-water mixed flow state of the fluid in the offshore gas well before entering the diameter change structure. At the same time, the gas storage tank 4 can effectively buffer gas pulsation and stabilize the gas supply pressure. Combined with the overall closed-loop return pipeline design, the experimental medium can be recycled and reused, ensuring the conduct of long-term steady-state experiments and improving the stability and continuity of the experimental conditions. Simultaneously, the experimental pipeline structure, employing a large-diameter pipe section 12, a variable-diameter connecting section 11, and a small-diameter pipe section 14, replicates the convex-contraction variable-diameter structure formed by the combination of continuous tubing and conventional tubing in offshore operations. This realistically reproduces the typical hydraulic characteristics of sudden airflow contraction, local eddies, liquid accumulation, and abrupt changes in flow resistance at the variable-diameter location, solving the problem that traditional uniform-diameter experimental pipelines cannot conduct research on the local liquid carrying and accumulation mechanisms at variable-diameter locations. Based on this, the invention deploys gas flow meters 7 and liquid flow meters 5 in the gas-liquid transport pipeline, and distributes pressure sensors along the experimental pipeline. This allows for real-time and synchronous detection of gas flow rate, liquid flow rate, and pipeline pressure parameters along the pipeline, enabling refined and quantitative acquisition of flow characteristics and pressure loss characteristics during the gas-liquid two-phase flow process in the variable-diameter pipe. It can systematically characterize the influence mechanism of the variable-diameter structure on liquid carrying capacity, flow law, and liquid accumulation characteristics, providing a reliable experimental basis and data support for revealing the gas-liquid two-phase flow mechanism at the variable-diameter location of offshore continuous tubing and optimizing the offshore velocity tubing drainage and gas extraction process.

[0021] The gas-water mixing system also includes multiple sets of regulating valves, which are respectively installed between the gas compressor 1 and the gas storage tank 4, between the gas storage tank 4 and the gas-water mixing section 8, and on the delivery pipeline between the centrifugal pump 26 and the gas-water mixing section 8. These valves are used to independently regulate the delivery flow rate and pressure of the gas and liquid media. The multiple sets of regulating valves can independently control the gas intake, gas delivery, and liquid delivery stages, achieving precise and independent regulation of gas and liquid flow rate and pressure. In a specific embodiment, regulating valve 2 is installed between the gas compressor 1 and the gas storage tank 4, regulating valve 6 is installed between the gas storage tank 4 and the gas-water mixing section 8, and regulating valve 3 is installed on the delivery pipeline between the centrifugal pump 26 and the gas-water mixing section 8.

[0022] The measuring device also includes an angle adjustment component, which includes an adjustable bracket 13 and a flexible connecting hose 10. The experimental pipeline is installed on the adjustable bracket 13. The gas-water mixing section 8 and the variable diameter connecting section 11 are connected by the flexible connecting hose 10. By adding the angle adjustment component, relying on the adaptability of the flexible connecting hose 10 and the support of the adjustable bracket 13, the experimental pipeline can be adjusted to a full angle of 0° to 90° to simulate the flow state of variable diameter pipes under different well inclination conditions in offshore gas wells, such as simulating the flow state of variable diameter pipes in various well types such as offshore horizontal wells, inclined wells, and vertical wells.

[0023] The measuring device also includes a visualization observation system, which includes a high-speed camera 17. The high-speed camera 17 is deployed at the large-diameter pipe section 12, the diameter-changing connecting section 11, and the small-diameter pipe section 14. The high-speed camera 17 is used to capture images of the gas-liquid two-phase flow patterns and flow characteristics at the large-diameter pipe section 12, the small-diameter pipe section 14, and the diameter-changing section.

[0024] The measuring device also includes a data control system, which comprises a paperless recorder 21 and a data analysis terminal 22. The paperless recorder 21 is electrically connected to the gas flow meter 7, the liquid flow meter 5, and the pressure sensor, respectively, and can record gas flow rate, liquid flow rate, and pressure parameters of each pipe section in real time. The data analysis terminal 22 is communicatively connected to the paperless recorder 21 to establish data communication, and is used to read, organize, and analyze experimental data to fit the gas-liquid two-phase flow law of the variable-diameter pipe. The data analysis terminal 22 can be a laptop computer.

[0025] Multiple pressure sensors are installed at both ends of the large-diameter pipe section 12, the variable-diameter connection section 11, and both ends of the small-diameter pipe section 14, respectively. These sensors are used to collect real-time pressure and flow pressure drop data at different locations in the experimental pipeline in sections and zones, thereby achieving accurate monitoring of pressure changes at the variable-diameter section.

[0026] The large-diameter pipe section 12, the variable-diameter connecting section 11, and the small-diameter pipe section 14 are all made of transparent plexiglass, enabling full-process visual observation of the gas-liquid two-phase flow pattern, liquid accumulation state, and liquid-carrying flow process inside the pipe. Furthermore, the large-diameter pipe section 12 and the small-diameter pipe section 14 are detachable and replaceable structures, adaptable to variable-diameter experimental conditions with different pipe diameter combinations, simulating the convex-contraction variable-diameter structure formed by continuous offshore tubing and conventional tubing.

[0027] In this embodiment, a measurement method for a device for measuring the liquid carrying and flow characteristics at a change in diameter of a marine coiled tubing is also constructed. Based on the aforementioned device for measuring the liquid carrying and flow characteristics at a change in diameter of a marine coiled tubing, the method includes the following steps: S1. Check the connection integrity of the gas-water mixing system, experimental pipelines, parameter measurement system and visualization observation system, debug the operating status of each device, calibrate the measurement accuracy of flow meters and pressure sensors, and ensure that the experimental data acquisition is accurate and reliable. S2. Set the experimental variable diameter combination parameters, adjust the tilt angle of the experimental pipeline through the adjustable bracket 13, and replace the large diameter pipe section 12 and small diameter pipe section 14 with the corresponding pipe diameter specifications. S3. Start the gas compressor 1 and centrifugal pump 26 to deliver gaseous and liquid media to the gas-water mixing section 8 respectively. Adjust the gas-liquid delivery flow rate through the regulating valve to obtain the gas-water two-phase mixed medium under the preset working conditions. The mixed gas-water two-phase medium flows into the experimental pipeline and flows through the variable diameter connection section 11, the large diameter pipe section 12, and the small diameter pipe section 14 in sequence, and finally flows back to the water tank 25 to form a closed loop circulation. S4. Real-time gas and liquid flow parameters are collected by gas flow meter 7 and liquid flow meter 5. Pipeline pressure and pressure drop parameters are collected in sections by each pressure sensor. Simultaneously, the gas and liquid flow patterns and liquid accumulation and liquid-carrying flow status in the variable diameter pipe are captured and recorded by high-speed camera 17. S5. Store all experimental data using the paperless recorder 21, organize experimental parameters using the data analysis terminal 22, and analyze the gas-liquid two-phase flow characteristics and liquid carrying law in the variable diameter pipe under different pipe diameter combinations, different well inclinations, and different gas-liquid flow rate coupling effects by combining the visualized flow pattern image.

[0028] This measurement method establishes a standardized experimental procedure from device calibration, operating condition setup, media supply, cyclic experiments, synchronous acquisition, to data analysis. The method features a closed-loop logic and standardized steps, effectively avoiding experimental operational errors and ensuring the consistency and repeatability of multiple comparative experiments. It can systematically conduct variable-diameter liquid-carrying experiments under multiple operating conditions and variables, providing a standardized experimental system to support the quantitative analysis of flow patterns. It employs a multi-point synchronous acquisition mode to achieve time-synchronous matching of flow rate, pressure, and flow pattern data, distinguishing the effects of variable-diameter structures on gas-liquid two-phase flow, liquid-carrying capacity, and liquid accumulation. It achieves precise time-dimensional matching of flow rate, pressure, and flow pattern data, avoiding data misalignment and distortion caused by asynchronous acquisition of multiple parameters in traditional experiments.

[0029] The experimental variable diameter combination parameters include pipe diameter parameters, pipeline spatial inclination angle parameters, variable diameter boundary operation coupling parameters, and small-tube internal assembly parameters. Specifically, the pipe diameter parameters are adjusted by using a replaceable pipe structure to change the inner diameter ratio of the large-diameter pipe section 12 and the small-diameter pipe section 14, as well as the overall variable diameter ratio, simulating the matching combination of different specifications of production tubing and coiled tubing in the field. The pipeline spatial inclination angle parameters are adjusted by using an adjustable support 13 and a flexible connecting hose 10 to achieve full-angle pipeline inclination adjustment from 0° to 90°, replicating different actual well inclination environments such as horizontal, inclined, and vertical in offshore gas wells. The variable diameter boundary operation coupling parameters are adjusted by using a regulating valve to change the gas phase flow rate, liquid phase flow rate, and gas-liquid ratio, matching the fluid flow boundary conditions under different production discharge rates of the gas well. The small-tube internal assembly parameters are adjusted by using a snap ring limiting structure to adjust the axial insertion depth of the small-diameter pipe section 14 inside the large-diameter pipe section 12 and the degree of tubing string eccentricity, replicating the actual tubing string assembly state with different internal installation deviations and insertion depths in the field.

[0030] A specific embodiment of the measurement method for the liquid carrying and flow law measurement device at the diameter change of offshore coiled tubing is as follows: The experimental medium is air and water. The gas is supplied by a gas compressor 1 and stored in a gas storage tank 4. It enters the gas-water mixing section 8 through a regulating valve 6 and a gas flow meter 7. The gas flow rate is regulated by a regulating valve 2, and the gas flow rate is transmitted to a paperless recorder 21 via a cable by the gas flow meter 7. The paperless recorder 21 records the gas flow rate. A centrifugal pump 26 pumps water from a water tank 25 to the gas-water mixing section 8. The water flow rate is measured by a liquid flow meter 5, and the water flow rate is regulated by a regulating valve 3. The above regulating valves can control the gas and water injection rates throughout the experiment, thereby conducting experiments to measure the liquid carrying and flow law at the diameter change under different gas and liquid velocities.

[0031] Gas and water flow into the large-diameter pipe section 12 after passing through the gas-water mixing section 8. The pressure at both ends is measured by pressure sensors 9 and 19, respectively, and transmitted to the paperless recorder 21 via cable. The gas-water two-phase flow pattern in the large-diameter pipe section 12 is captured by a high-speed camera 17. This allows for experiments measuring the liquid carrying capacity and flow patterns within the large-diameter pipe of a variable-diameter structure, and also for measuring the corresponding pressure drop in the gas-water two-phase flow.

[0032] Gas and water pass through the diameter change point in the large-diameter pipe section 12. The pressure at the diameter change point is measured by the pressure sensor 18 and transmitted to the paperless recorder 21 via cable. The gas-water two-phase flow pattern at the diameter change point is captured by the high-speed camera 17. The large-diameter pipe section 12 and the small-diameter pipe section 14 can be replaced with pipe columns of different diameters to realize the liquid carrying and flow law measurement experiments under different diameter change conditions. At the same time, the corresponding pressure drop of the gas-water two-phase flow can also be measured.

[0033] Gas and water enter the smaller diameter pipe section 14 through the diameter change point. The pressure at both ends is measured by pressure sensors 15 and 16, respectively, and transmitted to the paperless recorder 21 via cable. The gas-water two-phase flow pattern inside the smaller diameter pipe section 14 is captured by a high-speed camera 17. This allows for the measurement of liquid carrying capacity and flow patterns within the smaller diameter pipe in a variable diameter structure, and also the measurement of the corresponding pressure drop in the gas-water two-phase flow.

[0034] The gas-water mixing section 8 and the variable diameter connection section 11 are connected by a flexible connecting hose 10. The large diameter pipe section 12 and the small diameter pipe section 14 of the experimental pipeline are fixed on the adjustable bracket 13, which can be adjusted from 0° to 90°, thereby realizing the experimental simulation of liquid carrying and flow law measurement at the variable diameter under arbitrary angle conditions.

[0035] Compared with the shortcomings and deficiencies of existing technologies, the present invention has the following beneficial effects: 1. Equivalent simulation technology of variable diameter structure: The variable diameter connecting section 11, large diameter pipe section 12 and small diameter pipe section 14 are connected in sequence, and the small diameter pipe section 14 is set in the large diameter pipe section 12 to simulate the "convex-contraction structure" formed by the end of the marine continuous oil pipe and the existing oil pipe, so as to realize the experimental study of liquid carrying and flow law at the variable diameter section.

[0036] 2. Gas-water two-phase circulation supply and control technology: The experimental circuit consists of a gas compressor 1, a gas storage tank 4, a centrifugal pump 26, a water tank 25, a gas-water mixing section 8, a gas flow meter 7, and a liquid flow meter 5. The gas and water injection speed is controlled by regulating valves to meet the liquid carrying experimental requirements under different gas and liquid speed conditions.

[0037] 3. Real-time pressure measurement technology at multiple points at diameter changes: Pressure sensors are installed at both ends of the large-diameter pipe section 12, at the diameter change point, and at the small-diameter pipe section 14 to collect pressure and pressure drop changes at different locations in real time, which is used to analyze the impact of the diameter change structure on liquid carrying capacity and flow resistance.

[0038] 4. Transparent pipe section visualization flow pattern observation technology: The large-diameter pipe section 12 and the small-diameter pipe section 14 are made of transparent plexiglass tubes, and are used in conjunction with a high-speed camera 17 to capture the gas-water two-phase flow pattern of each pipe section and the diameter change point, so as to realize the visualization observation of the liquid carrying process and flow law.

[0039] 5. Multi-angle and multi-diameter operating condition adaptation technology: The experimental pipeline can be adjusted from 0° to 90° by connecting the hose 10 and the adjustable bracket 13. At the same time, the large-diameter pipe section 12 and the small-diameter pipe section 14 can be replaced with different diameters to carry out liquid carrying law tests under different tilt angles and different diameter changes.

[0040] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A device for measuring the liquid carrying and flow characteristics at the diameter change point of a marine coiled tubing, characterized in that, This includes an air-water mixing system, experimental piping, and a parameter measurement system; The gas-water mixing system includes a water tank (25), a centrifugal pump (26), a gas compressor (1), a gas storage tank (4), and a gas-water mixing section (8). The gas outlet of the gas compressor (1) is connected to the gas inlet of the gas storage tank (4) through a pipeline. The gas outlet of the gas storage tank (4) is connected to the gas input of the gas-water mixing section (8) through a pipeline. The water outlet of the water tank (25) is connected to the water inlet of the centrifugal pump (26) through a pipeline. The water outlet of the centrifugal pump (26) is connected to the liquid input of the gas-water mixing section (8) through a pipeline. The experimental pipeline includes a variable diameter connecting section (11), a large diameter pipe section (12), and a small diameter pipe section (14) connected in sequence. The input end of the large diameter pipe section (12) is connected to the output end of the gas-water mixing section (8) through the variable diameter connecting section (11). The small diameter pipe section (14) is fitted inside the large diameter pipe section (12) by a retaining spring. The output end of the small diameter pipe section (14) is connected to the water tank (25) through a return pipe. The parameter measurement system includes a gas flow meter (7), a liquid flow meter (5), and a pressure sensor. The gas flow meter (7) is installed on the gas delivery pipeline between the gas storage tank (4) and the gas-water mixing section (8). The liquid flow meter (5) is installed on the liquid delivery pipeline between the centrifugal pump (26) and the gas-water mixing section (8). The pressure sensor is distributed and installed on the experimental pipeline.

2. The device for measuring liquid carrying and flow patterns at the diameter change point of a marine coiled tubing according to claim 1, characterized in that, The gas-water mixing system also includes multiple sets of regulating valves, which are respectively installed between the gas compressor (1) and the gas storage tank (4), between the gas storage tank (4) and the gas-water mixing section (8), and on the delivery pipeline between the centrifugal pump (26) and the gas-water mixing section (8).

3. The device for measuring liquid carrying and flow patterns at the diameter change point of a marine coiled tubing according to claim 1, characterized in that, The measuring device also includes an angle adjustment component, which includes an adjustable bracket (13), and the experimental pipeline is mounted on the adjustable bracket (13).

4. The device for measuring liquid carrying and flow patterns at the diameter change point of a marine coiled tubing according to claim 1, characterized in that, The measuring device also includes a flexible connecting hose (10), through which the gas-water mixing section (8) and the variable diameter connecting section (11) are connected.

5. The device for measuring liquid carrying and flow patterns at the diameter change point of a marine coiled tubing according to claim 1, characterized in that, The measuring device also includes a visualization observation system, which includes a high-speed camera (17) and is deployed corresponding to the large-diameter pipe section (12), the variable-diameter connecting section (11), and the small-diameter pipe section (14).

6. The device for measuring liquid carrying and flow patterns at the diameter change point of a marine coiled tubing according to claim 1, characterized in that, The measuring device also includes a data measurement and control system, which includes a paperless recorder (21) and a data analysis terminal (22). The paperless recorder (21) is electrically connected to the gas flow meter (7), the liquid flow meter (5), and the pressure sensor, respectively; The data analysis terminal (22) is communicatively connected to the paperless recorder (21).

7. The device for measuring liquid carrying and flow patterns at the diameter change point of a marine coiled tubing according to claim 1, characterized in that, Multiple pressure sensors are provided, and the multiple pressure sensors are respectively installed at both ends of the large-diameter pipe section (12), the variable diameter connecting section (11), and both ends of the small-diameter pipe section (14).

8. The device for measuring liquid carrying and flow patterns at the diameter change point of a marine coiled tubing according to claim 1, characterized in that, The large-diameter pipe section (12), the variable-diameter connecting section (11), and the small-diameter pipe section (14) are all made of transparent organic glass.

9. A measurement method for a device for measuring the liquid carrying capacity and flow pattern at a diameter change in offshore coiled tubing, based on the device for measuring the liquid carrying capacity and flow pattern at a diameter change in offshore coiled tubing as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Check the connection integrity of the gas-water mixing system, experimental pipelines, parameter measurement system and visualization observation system, debug the operating status of each device, and calibrate the measurement accuracy of flow meters and pressure sensors; S2. Set the experimental variable diameter combination parameters, adjust the tilt angle of the experimental pipeline through the adjustable bracket (13), and replace the large diameter pipe section (12) and small diameter pipe section (14) with the corresponding pipe diameter specifications. S3. Start the gas compressor (1) and centrifugal pump (26) to deliver gas and liquid media to the gas-water mixing section (8) respectively. Adjust the gas-liquid delivery flow rate through the regulating valve to obtain the gas-water two-phase mixed medium under the preset working conditions. S4. Real-time gas and liquid flow parameters are collected by gas flow meter (7) and liquid flow meter (5). Pipeline pressure and pressure drop parameters are collected in segments by each pressure sensor. At the same time, the gas and liquid flow pattern and liquid accumulation and liquid-carrying flow state in the variable diameter pipe are captured and recorded by high-speed camera (17). S5. Store all experimental data using a paperless recorder (21), organize experimental parameters using a data analysis terminal (22), and analyze the gas-liquid two-phase flow characteristics and liquid carrying law in variable diameter pipes under different pipe diameter combinations, different well inclinations, and different gas-liquid flow coupling effects by combining visualized flow pattern images.

10. The measurement method of the device for measuring the liquid carrying and flow law at the diameter change of offshore coiled tubing according to claim 9, characterized in that, The experimental diameter variation combination parameters include pipe diameter parameters, pipe space inclination angle parameters, diameter variation boundary operation coupling parameters, and small pipe internal assembly parameters.

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