In-situ observation and wax stripping resistance test device for wax coating of crude oil pipeline pigging

Abstract

The present application provides a crude oil pipeline pigging wax layer stripping in-situ observation and wax removal resistance test experimental device, which comprises a power control system, a temperature control system, a wax removal experimental system and a data acquisition system; the wax removal experimental system comprises a transparent organic glass track for simulating a crude oil pipeline and a water bath temperature control platform, and further comprises a pig placed at the transparent organic glass track; the transparent organic glass track is fixed at the water bath temperature control platform; the water bath temperature control platform is placed below a water bath temperature control platform guide rail and is connected with a stepping motor of the power control system through a transmission mechanism; a tension sensor of the data acquisition system is connected with the pig through a rope; the present application overcomes the "black box problem" existing in the pipeline oil transportation process, and the in-situ direct observation of the wax removal process is beneficial to the intuitive understanding of the wax removal process, and the internal relationship between the wax removal efficiency, the wax removal driving force and the wax layer damage force and the temperature, the wax removal speed and the wax deposit properties can be explored through experiments.

Description

Technical Field

[0001] The invention relates to the technical field of experimental equipment, in particular to an experimental device for in-situ observation of wax layer peeling and wax removal resistance testing in a crude oil pipeline. Background Art

[0002] Oil is one of the world's most important energy sources and is known as the "blood of industry." During pipeline transportation, when the ambient temperature falls below the wax appearance temperature (WAT) of the crude oil, wax components precipitate from the crude oil and deposit on the pipe wall.

[0003] Wax deposition reduces the effective flow area of ​​the pipeline, decreases the transportation capacity, increases transportation energy consumption, and in severe cases even causes the pipeline to stop transporting, resulting in huge economic losses.

[0004] Over 80% of my country's crude oil is waxy, making wax deposition a particularly serious problem. Consequently, wax deposition has long been a hot topic of research within the petroleum industry, both domestically and internationally. While wax deposition can be prevented through pipeline insulation or heat tracing, or by adding chemical paraffin inhibitors, these measures are not always economically feasible. Typically, mechanical pigs are used regularly to unclog pipelines, reduce pressure drop, and improve pipeline capacity.

[0005] During a pigging operation, a ball launcher at the oil transfer station first deploys a pig into the pipeline through a specific process. During the pigging process, the oil flow propels the pig through the pipeline, stripping away deposits from the pipe wall and pushing them out. During pig movement, the pig is primarily subject to pressure differential forces across the ball, interference friction between the ball and the wall, shear resistance from wax deposits on the pipe wall, and the weight component of the pig's movement (for inclined pipe sections). The resistance from wax deposits is particularly critical, directly influencing the pattern of wax peeling.

[0006] Although pipeline pigging is a routine operation for a considerable number of pipelines, because oil pipelines are closed "black box" models, workers cannot observe the destruction and stripping process of wax deposits during the wax removal process. Therefore, they can only rely on on-site operating experience and select balls based on experience, resulting in an extremely high risk of ball jams and wax blockages during the pigging operation. If the resistance of the pipe wall deposit layer is underestimated, a "ball jam" accident may occur; if the resistance of the wax accumulation in front of the ball is underestimated, a "wax blockage" accident may occur. If the pig is stuck in the pipeline, it will affect the normal operation of the pipeline and may even cause the pipeline to initially solidify and shut down. To avoid such accidents, it is necessary to study the laws of wax stripping on the pipe wall during the pigging process to provide a theoretical basis for formulating reasonable wax removal plans.

[0007] The definitions of the relevant technical terms and abbreviations in the above content are as follows:

[0008] Wax deposition: When waxy crude oil is transported through pipelines, when the temperature drops below the wax precipitation point (the temperature at which the wax component in the crude oil begins to crystallize), wax precipitates and deposits on the inner walls of the pipeline. As the wax layer thickens, the pipeline's flow area decreases, flow resistance increases, pipeline capacity decreases, and operating energy consumption increases. In severe cases, it can even cause wax blockage or production shutdowns. Therefore, regular cleaning is essential to remove wax deposits and other impurities from oil pipelines to ensure safe and economical operation.

[0009] Pipe cleaning: The process of removing wax deposits and condensate from oil pipelines, condensate and hydrates from gas pipelines, and other impurities such as rust, silt, and scale. Pipe cleaning devices are widely used in oil and gas pipeline cleaning. During pipe cleaning, a pig (or ball) is dropped into the pipeline at a pumping station, heating station, or compressor station. Driven by the pressure of the fluid within the cleaning pipeline, the pig moves forward, using its scraping, flushing, vibrating, and crushing functions to remove dirt from the pipe walls and push accumulated impurities out of the pipe.

[0010] A pipe pig (ball): A specialized tool that is dropped into the interior of an oil and gas pipeline to remove debris such as wax, condensate, hydrates, condensate, mud, sand, and rust. Pipe pigs can be categorized into various types based on material, shape, structure, and purpose. Generally, a cup pig removes deposits from the pipe wall through a sealing cup. These cups typically come in either straight or disc shapes, with an interference fit of 0-5%. Summary of the Invention

[0011] The present invention proposes an experimental device for in-situ observation of wax layer stripping and wax removal resistance testing during crude oil pipeline cleaning, which enables experimenters to directly observe the wax removal process in situ, is conducive to forming an intuitive understanding of the wax removal process, and can study the wax layer destruction law during the pipe cleaning process by simulating different pipeline scenarios. Furthermore, the intrinsic relationship between wax removal efficiency, wax removal driving force and wax layer destructive force and temperature, wax removal speed and wax deposit properties can be explored through experiments.

[0012] The present invention adopts the following technical solutions.

[0013] An experimental device for in-situ observation of wax layer peeling during cleaning of a crude oil pipeline and for testing wax cleaning resistance, the experimental device comprising a power control system, a temperature control system, a wax cleaning experimental system and a data acquisition system; the wax cleaning experimental system comprising a transparent organic glass track (4) for simulating a crude oil pipeline and a pipe cleaner (2) placed on the track; the transparent organic glass track is fixed to a water bath temperature control platform; the water bath temperature control platform is placed below a guide rail (7) of the water bath temperature control platform and is connected to a stepper motor of a power control system via a transmission mechanism; and the tension sensor of the data acquisition system is connected to the pipe cleaner via a rope.

[0014] The transparent organic glass track includes two L-shaped transparent organic glass guide rails and a transparent organic glass guide rail cover; the data acquisition system includes a PC.

[0015] The temperature control system includes a water bath temperature control platform and two water bath heating devices connected thereto; a baffle is provided inside the water bath temperature control platform, which is used to allow water to flow fully through the internal space of the platform to ensure a uniform temperature on the water bath temperature control platform; the water bath temperature control platform is provided with two water inlets and two water outlets, which are respectively connected to the two water bath devices through plastic hoses.

[0016] The transparent organic glass track is a pipe cleaning channel with adjustable width, and the size of the pipe cleaning device matches the size of the pipe cleaning channel.

[0017] The transmission mechanism is a screw connection system of the power control system; the power control system also includes a wax cleaning device master control for controlling the movement speed and movement direction of the water bath temperature control platform.

[0018] The method for performing in-situ observation of wax layer stripping and wax removal resistance test on the experimental device for crude oil pipeline specifically comprises the following steps:

[0019] Step S1, start the water bath heating device to adjust the temperature of the transparent organic glass track to the constant temperature state required for the experiment;

[0020] Step S2: placing the pipe cleaner at the right end of the transparent organic glass track; pouring the prepared simulated oil on the surface of the transparent organic glass track to form a solidified wax layer under constant temperature and time conditions;

[0021] Step S3: The stepper motor drives the water bath temperature control platform and the transparent organic glass track to move away from the tension sensor. During this process, the wax layer cast on the surface of the transparent organic glass track is cleaned by the pig.

[0022] Step S4: When the pig cleans the wax layer on the surface of the transparent organic glass track, the experimenter observes the wax layer peeling and uses a tension sensor to measure the wax removal resistance of the pig in real time. The data acquisition system collects and exports the measured tension test data data1;

[0023] In step S5, the stepper motor first drives the water bath temperature control platform and the plexiglass track to return to their initial positions, placing the pipe cleaner in the same position as described in step S2. The stepper motor then drives the water bath temperature control platform and the plexiglass track to move in the opposite direction away from the tension sensor. The tension sensor measures the force applied to the pipe cleaner in real time, and the data acquisition system collects and exports the measured tension test experimental data data2, which corresponds to the baseline force during the wax cleaning process.

[0024] The specific method of step S2 is: use paraffin wax and white oil to prepare simulated oil; after controlling the temperature of the transparent organic glass track to the target temperature through the temperature control system, pour the prepared high-temperature simulated oil into the inside of the transparent organic glass track, let it stand for a period of time until the simulated oil forms a uniform, stable wax deposit with the same thickness everywhere inside the organic glass guide rail, which serves as the experimental wax layer.

[0025] In the crude oil pipeline pig wax layer stripping in-situ observation and wax removal resistance test experiment, the specific method for calculating the wax removal efficiency is as follows:

[0026] Step A1: Place the prepared simulated oil in a beaker, heat, and stir until the paraffin is completely dissolved. Then, weigh the beaker containing the simulated oil using a high-precision balance, and record the weighing result as mass m1.

[0027] Step A2: Pour the simulated oil in the beaker into the transparent plexiglass track until the required amount is reached. Then, weigh the beaker containing the simulated oil using a high-precision balance. The weighing result is recorded as mass m2. The mass of the wax layer poured into the transparent plexiglass track is m3 = m1 - m2.

[0028] Step A3: After the transparent organic glass track stops moving, weigh the mass of wax removed by the pipe cleaner and record it as m4. The wax removal efficiency is .

[0029] In the in-situ observation of wax layer peeling during crude oil pipeline pigging and the wax removal resistance test, the wax layer destructive force is obtained by subtracting data2 from data1.

[0030] In the in-situ observation of wax stripping during crude oil pipeline pigging and the wax removal resistance test, the variation patterns of the wax removal driving force under different wax removal scenarios in the pipeline were obtained by simulating the following methods:

[0031] The method for simulating the actual wax removal process of oil pipelines at different ambient temperatures is as follows: using a water bath temperature control platform, controlling the formation of wax deposits in the range of 0-50°C, and conducting wax removal experiments at different temperatures to simulate the actual wax removal process of oil pipelines, and obtain the variation of the wax removal driving force with temperature;

[0032] The method for simulating the wax removal process of an actual oil pipeline under different thicknesses is as follows: in the wax pouring process of step S2, the wax deposit thickness is controlled by controlling the wax pouring amount, thereby simulating the wax removal process of an actual oil pipeline under conditions of different thicknesses at the same temperature, and obtaining the variation pattern of the wax removal driving force with the wax layer thickness;

[0033] The method for simulating the actual wax removal process of an oil pipeline under different wax content conditions is as follows: the wax content of the simulated oil is controlled during the preparation of the simulated oil to simulate the wax removal process when the oil pipeline transports crude oil with different wax contents. Through experiments, the variation law of the wax removal driving force with the wax content can be obtained.

[0034] In the present invention, the wax cleaning experimental pipe section is designed as a horizontal transparent organic glass with a rectangular cross-section, which can directly observe the wax cleaning process of the pipe cleaner and overcome the "black box problem" existing in the actual wax cleaning process; accordingly, the pipe cleaner is redesigned to conform to the operation of the experimental pipeline; the movement form of the pipe cleaner is improved, from the movement of the pipe cleaner relative to the pipeline and the ground to the movement of the pipeline relative to the pipe cleaner and the ground, which is conducive to observing the process of the pipe cleaner stripping wax deposits.

[0035] The present invention designs an experimental device for in-situ observation of wax layer stripping and wax removal resistance testing during crude oil pipeline pigging (hereinafter referred to as the wax removal device). This device realizes the in-situ direct observation of the wax removal process for the first time, which is conducive to forming an intuitive understanding of the wax removal process, facilitating the study of the wax layer destruction law during the pigging process, and further exploring the intrinsic connection between the pigging process, the wax deposition process, and the properties of the wax deposits.

[0036] The present invention controls the wax precipitation characteristics of wax deposits by controlling the wax content of simulated oil, controls the hardness of wax deposits by controlling the temperature of a water bath temperature control platform, and controls the thickness of wax deposits by controlling the amount of wax poured, thereby studying the changing patterns of the destructive force of the wax layer and the wax removal efficiency under different wax precipitation characteristics, hardness, and thickness conditions. The destructive force of the wax layer can be obtained by a data acquisition system, and the wax removal efficiency can be obtained by calculating the ratio of the wax deposits peeled off by the pipe cleaner to the amount of wax poured. Using this device, on the one hand, the destruction and deformation process of wax deposits under the action of the pipe cleaner can be directly observed in situ, and the changing patterns of wax removal efficiency with factors such as wax precipitation characteristics, hardness, and thickness can be analyzed; on the other hand, the pulling force generated during the wax removal process can be collected in real time, thereby analyzing the changing patterns of wax removal resistance with factors such as wax precipitation characteristics, hardness, and thickness.

[0037] The present invention not only provides an experimental device for achieving the above-mentioned purpose of the invention, but also provides a method for testing wax removal efficiency and wax layer destructive power based on simulated wax deposits, including operating process and data analysis.

[0038] The crude oil pipeline pigging experimental device of the present invention has the following characteristics:

[0039] (1) Using a transparent organic glass experimental channel as a simulated wax pouring pipeline surface, the destruction and stripping process of wax deposits can be directly observed in situ, which can overcome the "black box problem" existing in actual pipeline cleaning operations;

[0040] (2) A water bath heating device is used to control the temperature of the water bath temperature control platform and the experimental pipeline. At the same time, a baffle is provided inside the water bath temperature control platform to prevent the formation of a "dead zone", thereby achieving precise temperature control of the test section and ensuring that the properties of the cast wax deposits are uniform and stable.

[0041] (3) Using a horizontal test pipe ensures that the thickness of the wax deposit is the same everywhere, which is conducive to obtaining more reliable key data on the destructive force of the wax layer;

[0042] (4) Three experimental pipes and pigs with different widths were designed to compare the pigging efficiency at different widths;

[0043] (5) Real-time collection and detection of tension data are realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0045] Attachment Figure 1 is a schematic diagram of the present invention;

[0046] In the figure: 1-tension sensor; 2-pipe cleaner; 3-bracket; 4-transparent plexiglass track; 5-water bath temperature control platform; 6-stepping motor; 7-screw connection system. DETAILED DESCRIPTION

[0047] As shown in the figure, an experimental device for in-situ observation of wax layer peeling and wax removal resistance testing during crude oil pipeline cleaning is provided. The experimental device includes a power control system, a temperature control system, a wax removal experimental system, and a data acquisition system. The wax removal experimental system includes a transparent organic glass track 4 and a water bath temperature control platform 5 for simulating a crude oil pipeline, and also includes a pipe cleaner 2 placed on the transparent organic glass track. The transparent organic glass track is fixed to the water bath temperature control platform. The water bath temperature control platform is placed under the water bath temperature control platform guide rail 7 and is connected to the stepper motor 6 of the power control system via a transmission mechanism. The tension sensor 1 of the data acquisition system is connected to the pipe cleaner via a rope.

[0048] The transparent organic glass track includes two L-shaped transparent organic glass guide rails and a transparent organic glass guide rail cover; the data acquisition system includes a PC.

[0049] The temperature control system includes a water bath temperature control platform and two water bath heating devices connected thereto; a baffle is provided inside the water bath temperature control platform, which is used to allow water to flow fully through the internal space of the platform to ensure a uniform temperature on the water bath temperature control platform; the water bath temperature control platform is provided with two water inlets and two water outlets, which are respectively connected to the two water bath devices through plastic hoses.

[0050] The transparent organic glass track is a pipe cleaning channel with adjustable width, and the size of the pipe cleaning device matches the size of the pipe cleaning channel.

[0051] The transmission mechanism is a screw connection system 7 of the power control system; the power control system also includes a wax cleaning device master control for controlling the movement speed and movement direction of the water bath temperature control platform.

[0052] The method for performing in-situ observation of wax layer stripping and wax removal resistance test on the experimental device for crude oil pipeline specifically comprises the following steps:

[0053] Step S1, start the water bath heating device to adjust the temperature of the transparent organic glass track to the constant temperature state required for the experiment;

[0054] Step S2: placing the pipe cleaner at the right end of the transparent organic glass track; pouring the prepared simulated oil on the surface of the transparent organic glass track to form a solidified wax layer under constant temperature and time conditions;

[0055] Step S3: The stepper motor drives the water bath temperature control platform and the transparent organic glass track to move away from the tension sensor. During this process, the wax layer cast on the surface of the transparent organic glass track is cleaned by the pig.

[0056] Step S4: When the pig cleans the wax layer on the surface of the transparent organic glass track, the experimenter observes the wax layer peeling and uses a tension sensor to measure the wax removal resistance of the pig in real time. The data acquisition system collects and exports the measured tension test data data1;

[0057] In step S5, the stepper motor first drives the water bath temperature control platform and the plexiglass track to return to their initial positions, placing the pipe cleaner in the same position as described in step S2. The stepper motor then drives the water bath temperature control platform and the plexiglass track to move in the opposite direction away from the tension sensor. The tension sensor measures the force applied to the pipe cleaner in real time, and the data acquisition system collects and exports the measured tension test experimental data data2, which corresponds to the baseline force during the wax cleaning process.

[0058] The specific method of step S2 is: use paraffin wax and white oil to prepare simulated oil; after controlling the temperature of the transparent organic glass track to the target temperature through the temperature control system, pour the prepared high-temperature simulated oil into the inside of the transparent organic glass track, let it stand for a period of time until the simulated oil forms a uniform, stable wax deposit with the same thickness everywhere inside the organic glass guide rail, which serves as the experimental wax layer.

[0059] In the crude oil pipeline pig wax layer stripping in-situ observation and wax removal resistance test experiment, the specific method for calculating the wax removal efficiency is as follows:

[0060] Step A1: Place the prepared simulated oil in a beaker, heat, and stir until the paraffin is completely dissolved. Then, weigh the beaker containing the simulated oil using a high-precision balance, and record the weighing result as mass m1.

[0061] Step A2: Pour the simulated oil in the beaker into the transparent plexiglass track until the required amount is reached. Then, weigh the beaker containing the simulated oil using a high-precision balance. The weighing result is recorded as mass m2. The mass of the wax layer poured into the transparent plexiglass track is m3 = m1 - m2.

[0062] Step A3: After the transparent organic glass track stops moving, weigh the mass of wax removed by the pipe cleaner and record it as m4. The wax removal efficiency is .

[0063] In the in-situ observation of wax layer peeling during crude oil pipeline pigging and the wax removal resistance test, the wax layer destructive force is obtained by subtracting data2 from data1.

[0064] In actual pipeline oil transportation, the temperature environment experienced by the same pipeline varies significantly at different times and seasons. For example, the temperature of an oil pipeline operating late at night is much lower than that of a pipeline operating at noon, and the temperature in winter is also lower than that in summer. As the temperature drops, the wax components in the crude oil begin to crystallize and precipitate, forming wax deposits. The lower the temperature, the harder the wax deposits, and the greater the driving force required to remove the wax. The formation of wax deposits has a significant negative impact on the safe and stable operation of the oil pipeline (see Background Art).

[0065] In the actual pipeline oil transportation process, the thickness of wax deposits formed in the same oil pipeline at different operating times and different ambient temperatures is different, so the required wax removal driving force is also different.

[0066] Crude oil from different oil fields has different wax contents. During actual pipeline transportation, the driving force required for wax removal varies depending on the wax content. Generally speaking, the higher the wax content, the higher the driving force required for wax removal.

[0067] In view of the characteristics of the above-mentioned specific pipeline wax removal operations, in the crude oil pipeline wax layer peeling in-situ observation and wax removal resistance test experiment, by simulating different wax removal scenarios in the oil pipeline, the variation pattern of the wax removal driving force in each scenario was obtained, including the following methods:

[0068] The method for simulating the actual wax removal process of oil pipelines at different ambient temperatures is as follows: using a water bath temperature control platform, controlling the formation of wax deposits in the range of 0-50°C, and conducting wax removal experiments at different temperatures to simulate the actual wax removal process of oil pipelines, and obtain the variation of the wax removal driving force with temperature;

[0069] The method for simulating the wax removal process of an actual oil pipeline under different thicknesses is as follows: in the wax pouring process of step S2, the wax deposit thickness is controlled by controlling the wax pouring amount, thereby simulating the wax removal process of an actual oil pipeline under conditions of different thicknesses at the same temperature, and obtaining the variation pattern of the wax removal driving force with the wax layer thickness;

[0070] The method for simulating the actual wax removal process of an oil pipeline under different wax content conditions is as follows: the wax content of the simulated oil is controlled during the preparation of the simulated oil to simulate the wax removal process when the oil pipeline transports crude oil with different wax contents. Through experiments, the variation law of the wax removal driving force with the wax content can be obtained.

[0071] Example:

[0072] In this example, the device consists of four parts: power control system, temperature control system, wax removal experimental system and data acquisition system. Figure 1 As shown, the power control system includes a stepper motor 6, a screw connection system and a water bath temperature control platform guide rail 7; two water bath devices and the water bath temperature control platform 5 provide a constant temperature for the wax cleaning experiment; under the traction of the stepper motor 6, the pipe cleaner 2 moves at a constant speed relative to the water bath temperature control platform 5 in the transparent organic glass 4 track; the tension sensor 1 is connected to the pipe cleaner 2 by a wire rope to measure the power provided by the power system during the wax cleaning process, which is observed in real time on the PC monitor.

[0073] In this example, the screw connection system is supported by a bracket 3 .

[0074] The power control system is composed of a wax cleaning device master control, a stepper motor, a screw connection system, and a water bath temperature control platform guide rail; the wax cleaning device master control can control the movement speed and direction of the water bath temperature control platform; the stepper motor, the screw connection system, the water bath temperature control platform guide rail, and the water bath temperature control platform are connected in sequence.

[0075] The temperature control system consists of two water bath heating units and a water bath temperature control platform. The platform is equipped with internal baffles to ensure that water flows fully through the platform's internal space and maintains a uniform temperature. The platform has two water inlets and two water outlets, connected to the two water baths by plastic hoses.

[0076] The wax removal experimental system consists of a water bath temperature control platform, two L-shaped transparent organic glass guide rails, a transparent organic glass guide rail cover and a pipe cleaner.

[0077] The water bath temperature control platform provides a movement plane and constant temperature for the experimental system; two L-shaped transparent organic glass guide rails and a transparent organic glass guide rail cover together form the movement channel of the pipe cleaner, and the width of the movement channel can be adjusted to 3cm, 4cm and 5cm respectively; the pipe cleaner has the same width and height as the channel and moves in the channel; the width of the pipe cleaner has three specifications, namely 3cm, 4cm and 5cm, which are the same as the track width. The present invention uses paraffin wax and white oil to configure the simulation oil. The water bath temperature control platform is controlled to the target temperature, and the configured high-temperature simulation oil is poured into the inside of the organic glass guide rail. After standing for 5 minutes, a uniform, stable and uniform thickness wax deposit is formed inside the organic glass guide rail. Under the action of the pipe cleaner, the wax deposit inside the organic glass guide rail is destroyed and peeled off. The wax cleaning efficiency can be calculated by calculating the ratio of the peeled wax deposit to the amount of wax poured.

[0078] The data acquisition system consists of a pipe cleaner, a tension sensor and transmitter, and a PC monitor. The tension data is displayed in real time on the PC monitor. Simple processing of the tension data reveals the changing patterns of wax layer destructive force during the wax removal process.

[0079] The experimental steps using this experimental device are as follows:

[0080] (1) Turn on the water bath, set the temperature to the experimental temperature, and start the external circulation;

[0081] (2) Turn on the main control of the wax cleaning device and adjust the water bath temperature control platform to the initial position (its right side is flush with the pipe cleaner); install a glass baffle with a sealing ring on the left side of the organic glass guide rail;

[0082] (3) Open the tension measurement software on the PC monitor and put it into the preparatory working state;

[0083] (4) Prepare 100 g of simulated oil with a ratio of 20 wt% paraffin and 80 wt% white oil, place it in a beaker, heat it to 70 °C and stir it at constant temperature for 10 min to completely dissolve the paraffin; weigh it with a high-precision balance and record the mass m1;

[0084] (5) Slowly pour the simulated oil into the inside of the plexiglass guide rail and let it stand for 5 minutes until it is completely solidified; weigh the beaker with a high-precision balance and record the mass m2. The mass of the poured wax is m3 = m1 - m2;

[0085] (6) Use a tape measure to measure the actual wax pouring length, record it as L1; remove the glass baffle with the sealing ring, and connect the pipe cleaner and the tension sensor;

[0086] (7) Set the tension measurement software to the acquisition state; set the wax cleaning device master control to the uniform rightward movement state;

[0087] (8) After the experimental device stops moving, set the tension measurement software to the stop state, end data collection, and export the tension test experimental data data1;

[0088] (9) Use a high-precision balance to weigh the mass of wax deposits removed by the pig and record it as m4; the wax removal efficiency is ;

[0089] (10) Remove the pipe cleaner, start the wax cleaning device master control, and move the water bath temperature control platform to the initial position;

[0090] (11) Align the pipe cleaner with the right side of the plexiglass guide rail and repeat step (7);

[0091] (12) After the experimental device stops moving, set the tension measurement software to the stop state, end data collection, and export the tension test experimental data data2, which corresponds to the baseline force during the wax cleaning process;

[0092] (13) Clean the pipe cleaner and plexiglass guide rails, return all equipment to their original positions, and end the experiment.

[0093] In this example, the data acquisition system mainly consists of a DYLY-103 tension sensor and real-time monitoring software. The DYLY-103 tension sensor has a range of 0-10kg and an accuracy of 0.03%. The collected pressure is output to the PC monitor in real time, and the PC monitor saves and outputs the collected pressure data points. In this example, the wax removal efficiency can be calculated using the formula Calculation: The destructive force of the wax layer can be obtained by subtracting data2 from data1.

Claims

1. Crude oil pipeline pigging wax layer stripping in-situ observation and wax removal resistance test experimental device, characterized by: The experimental device includes a power control system, a temperature control system, a wax removal experimental system and a data acquisition system; the wax removal experimental system includes a transparent organic glass track (4) for simulating a crude oil pipeline and a pipe cleaner (2) placed on the track; the transparent organic glass track is fixed to a water bath temperature control platform; the water bath temperature control platform is placed below a guide rail (7) of the water bath temperature control platform and is connected to a stepper motor of the power control system via a transmission mechanism; the tension sensor of the data acquisition system is connected to the pipe cleaner via a rope; The temperature control system includes a water bath temperature control platform and two water bath heating devices connected thereto; a baffle is provided inside the water bath temperature control platform, which is used to allow water to fully flow through the internal space of the platform to ensure a uniform temperature on the water bath temperature control platform; the water bath temperature control platform is provided with two water inlets and two water outlets, which are respectively connected to the two water bath devices through plastic hoses; The transmission mechanism is a screw connection system of the power control system; the power control system also includes a wax cleaning device master control for controlling the speed and direction of movement of the water bath temperature control platform; The method for performing in-situ observation of wax layer stripping and wax removal resistance test on the experimental device for crude oil pipeline specifically comprises the following steps: Step S1, start the water bath heating device to adjust the temperature of the transparent organic glass track to the constant temperature state required for the experiment; Step S2: placing the pipe cleaner at the right end of the transparent organic glass track; pouring the prepared simulated oil on the surface of the transparent organic glass track to form a solidified wax layer under constant temperature and time conditions; Step S3: The stepper motor drives the water bath temperature control platform and the transparent organic glass track to move away from the tension sensor. During this process, the wax layer cast on the surface of the transparent organic glass track is cleaned by the pig. Step S4: When the pig cleans the wax layer on the surface of the transparent organic glass track, the experimenter observes the wax layer peeling and uses a tension sensor to measure the wax removal resistance of the pig in real time. The data acquisition system collects and exports the measured tension test data data1; In step S5, the stepper motor first drives the water bath temperature control platform and the plexiglass track back to their initial positions, placing the pipe cleaner in the same position as in step S2. The stepper motor then drives the water bath temperature control platform and the plexiglass track again in a direction away from the tension sensor. The tension sensor measures the force acting on the pipe cleaner in real time, and the data acquisition system collects and exports the measured tension test data, data2, which corresponds to the baseline force during the wax cleaning process. In the in-situ observation of wax stripping during crude oil pipeline pigging and the wax removal resistance test, the variation patterns of the wax removal driving force under different wax removal scenarios in the pipeline were obtained by simulating the following methods: The method for simulating the actual wax removal process of oil pipelines under different ambient temperatures is as follows: using a water bath temperature control platform, controlling the formation of wax deposits in the range of 0-50°C, and conducting wax removal experiments at different temperatures to simulate the actual wax removal process of oil pipelines, and obtain the variation pattern of wax removal driving force with temperature; The method for simulating the wax removal process of an actual oil pipeline under different thicknesses is as follows: in the wax pouring process of step S2, the wax deposit thickness is controlled by controlling the wax pouring amount, thereby simulating the wax removal process of an actual oil pipeline under conditions of different thicknesses at the same temperature, and obtaining the variation pattern of the wax removal driving force with the wax layer thickness; The method for simulating the actual wax removal process of an oil pipeline under different wax content conditions is as follows: the wax content of the simulated oil is controlled during the preparation of the simulated oil to simulate the wax removal process when the oil pipeline transports crude oil with different wax contents. Through experiments, the variation law of the wax removal driving force with the wax content can be obtained.

2. The crude oil pipeline pigging wax layer stripping in-situ observation and wax removal resistance test experimental device according to claim 1 is characterized by: The transparent organic glass track includes two L-shaped transparent organic glass guide rails and a transparent organic glass guide rail cover; the data acquisition system includes a PC.

3. The crude oil pipeline pigging wax layer stripping in-situ observation and wax removal resistance test experimental device according to claim 1 is characterized by: The transparent organic glass track is a pipe cleaning channel with adjustable width, and the size of the pipe cleaning device matches the size of the pipe cleaning channel.

4. The crude oil pipeline pigging wax layer stripping in-situ observation and wax removal resistance test experimental device according to claim 1 is characterized by: The specific method of step S2 is: use paraffin wax and white oil to prepare simulated oil; after controlling the temperature of the transparent organic glass track to the target temperature through the temperature control system, pour the prepared high-temperature simulated oil into the inside of the transparent organic glass track, let it stand for a period of time until the simulated oil forms a uniform, stable wax deposit with the same thickness everywhere inside the organic glass guide rail, which serves as the experimental wax layer.

5. The crude oil pipeline pigging wax layer stripping in-situ observation and wax removal resistance test experimental device according to claim 4 is characterized by: In the crude oil pipeline pig wax layer peeling in-situ observation and wax removal resistance test experiment, the specific method for calculating the wax removal efficiency is as follows: Step A1: Place the prepared simulated oil in a beaker, heat, and stir until the paraffin is completely dissolved. Then, weigh the beaker containing the simulated oil using a high-precision balance, and record the weighing result as mass m1. Step A2: Pour the simulated oil in the beaker into the transparent plexiglass track until the required amount is reached. Then, weigh the beaker containing the simulated oil using a high-precision balance. The weighing result is recorded as mass m2. The mass of the wax layer poured into the transparent plexiglass track is m3 = m1 - m2. Step A3: After the transparent organic glass track stops moving, the mass of wax removed by the pipe cleaner is weighed and recorded as m4, which is the wax removal efficiency.

6. The crude oil pipeline pigging wax layer stripping in-situ observation and wax removal resistance test experimental device according to claim 4, characterized in that: In the in-situ observation of wax layer peeling during crude oil pipeline pigging and the wax removal resistance test, the wax layer destructive force is obtained by subtracting data2 from data1.

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