Test device for minimum flowable temperature of mixed service pipelines and method of use

Abstract

The present application relates to oil, gas and water three-phase mixed transportation fluid freezing point experimental test technical field, it is a kind of mixed transportation pipeline minimum flowable temperature test device and use method, the former includes water bath cabinet, coil pipe, first pressure sensor, second pressure sensor, ultrasonic measurement module, temperature regulating device and control unit, several turns of coil pipe are coiled in water bath cabinet.This application is reasonable and compact, when using, the mixed solution of water and methanol is filled in water bath cabinet, coil pipe is immersed in the mixed solution of water and methanol, by setting temperature regulating device, the cold quantity can be provided for the mixed solution in water bath cabinet, so as to reduce the temperature of mixed solution, by setting ultrasonic emission probe, ultrasonic receiving probe, ultrasonic measurement module can measure the ultrasonic propagation time of fluid in coil pipe, by setting check valve, ensure that all fluids flow in one direction, the minimum flowable temperature of mixed transportation fluid under multiple influence factors can be accurately measured.

Description

Technical Field

[0001] The invention relates to the technical field of experimental testing of the freezing point of a three-phase mixed transmission fluid of oil, gas and water, and is a testing device for the lowest flowable temperature of a mixed transmission pipeline and a use method thereof. Background Art

[0002] Oil and gas field exploration and development are gradually expanding into harsh natural environments such as oceans, deserts, and polar regions. Due to the difficulty and high cost of laying pipelines in these areas, three-phase oil, gas, and water transportation is difficult. Therefore, mixed oil, gas, and water transportation is often used. Field tests have shown that fluids in three-phase mixed pipelines can be transported normally at temperatures below the pour point of crude oil. Specifically, under mixed conditions, the minimum flowable temperature of the fluid is below the pour point of crude oil. Currently, there is no quantitative experimental device for measuring minimum flowable temperature, and no comprehensive explanation for the mechanism by which the minimum flowable temperature of mixed pipelines is below the pour point of crude oil has been proposed. Field experience shows that the minimum flowable temperature of mixed pipelines is affected by shear rate, gas-oil ratio, water content, and pour point. To study this issue, it is necessary to measure the minimum flowable temperature of mixed pipelines under a large number of different influencing factors. However, due to the stringent requirements for fluid temperature control, direct testing on field pipelines is not possible. Therefore, this patent designs an experimental device for measuring the minimum flowable temperature of pipelines. Summary of the Invention

[0003] The present invention provides a testing device and method for the minimum flowable temperature of a mixed pipeline, which overcomes the shortcomings of the above-mentioned existing technologies. It can effectively solve the problem that when obtaining the minimum flowable temperature data of a mixed pipeline under different influencing factors, it is difficult to conduct experiments directly on the pipeline on site due to the strict requirements of the experiment on fluid temperature control.

[0004] One of the technical solutions of the present invention is achieved through the following measures: a test device for the minimum flowable temperature of a mixed pipeline, comprising a water bath, a coil, a first pressure sensor, a second pressure sensor, an ultrasonic measurement module, a temperature control device and a control unit, wherein several coils are wound in the water bath, the first end of the coil is sealed and passes through the left rear part of the water bath, and the second end of the coil is sealed and passes through the left front part of the water bath, a one-way valve is provided on the coil, and an ultrasonic transmitting probe and an ultrasonic receiving probe are symmetrically installed on the outer side of the coil corresponding to the position between the one-way valve and the discharge valve, the lower end of the first pressure sensor is sealed and passed through the upper side of the water bath and then installed on the coil between the one-way valve and the left inner wall of the water bath, the lower end of the second pressure sensor is sealed and passed through the upper side of the water bath and then installed on the coil between the ultrasonic transmitting probe and the left inner wall of the water bath, a radiator is provided in the center of the coil, the radiator is connected to the temperature control device, a temperature sensor is installed on the upper right side of the water bath, the ultrasonic transmitting probe and the ultrasonic receiving probe are both connected to the ultrasonic measurement module, and the control unit is respectively connected to the first pressure sensor, the second pressure sensor, the ultrasonic measurement module, the temperature sensor and the temperature control device.

[0005] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions:

[0006] The above may also include a multiphase flow pump and a sampler, the outlet of the multiphase flow pump is fixedly connected to the first end of the coil, a sampling tube is fixedly connected between the inlet of the multiphase flow pump and the tubular structure sampler, a sampling valve is installed on the sampling tube, the second end of the coil is fixedly connected to a sample outlet tube, a discharge valve is installed on the sample outlet tube, and the multiphase flow pump is connected to the control unit.

[0007] The outer side of the middle of the sampler may be evenly spaced along the circumference with four internally and externally connected sampling holes, and a sampling branch pipe is fixedly connected between each sampling hole and the end of the sampling tube away from the multiphase flow pump.

[0008] The outer side of the water bath may be provided with a protective shell, and the inner side of the protective shell and the inner side of the water bath may be filled with an insulation layer.

[0009] The second technical solution of the present invention is achieved by the following measures: a method for using a device for testing the minimum flowable temperature of a mixed pipeline, characterized by comprising the following steps:

[0010] Step 1: Close the sampling valve and the discharge valve, and connect the sampler and the sample outlet pipe to the oil outlet pipeline of the single well;

[0011] Step 2: Add a mixture of water and methanol into the water bath;

[0012] Step 3: Open the sampling valve and the discharge valve, start the multiphase flow pump, control the speed of the multiphase flow pump, and deliver the fluid with the set shear rate into the coil;

[0013] Step 4: The control unit controls the temperature regulating device to operate so that the temperature of the mixed liquid in the water bath decreases at a set rate;

[0014] Step 5: The ultrasonic measurement module transmits ultrasonic waves into the coil through the ultrasonic transmitting probe. The ultrasonic receiving probe receives the ultrasonic waves transmitted by the ultrasonic transmitting probe and feeds them back to the ultrasonic measurement module. The ultrasonic measurement module measures the propagation time of the ultrasonic waves in the mixed fluid in the coil. When the propagation time of the ultrasonic waves from the ultrasonic transmitting probe to the ultrasonic receiving probe changes, the temperature sensor data at this time is T1;

[0015] When the data of the first pressure sensor and the second sensor suddenly change, the temperature sensor data at this time is T2;

[0016] The smaller value between T1 and T2 is the minimum flowable temperature of the mixed pipeline.

[0017] The following is a further optimization and / or improvement of the second technical solution of the above invention:

[0018] The temperature of the mixed solution in the water bath was decreased at a rate of 0.1°C / min.

[0019] The above step 1 is specifically as follows: add pure water from the sampler, open the multiphase flow pump and the discharge valve to flush the coil, and after the flushing is completed, introduce dry nitrogen to drain and dry the liquid in the coil, close the sampling valve and the discharge valve, and fix the sampler and the sample outlet pipe to the oil outlet pipeline of the single well.

[0020] The present invention has a reasonable and compact structure. When in use, a mixture of water and methanol is added to a water bath, and the coil is immersed in the mixture of water and methanol. By providing a temperature regulating device, cooling capacity can be provided for the mixture in the water bath, thereby reducing the temperature of the mixture. By providing an ultrasonic transmitting probe, an ultrasonic receiving probe, and an ultrasonic measuring module, the ultrasonic propagation time of the fluid in the coil can be measured. By providing a one-way valve, it is ensured that all fluids flow in one direction, and the lowest flowable temperature of the mixed fluid on site under multiple influencing factors can be accurately measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Attachment Figure 1 This is a schematic diagram of the top cross-sectional structure of Example 1.

[0022] Attachment Figure 2 This is a schematic diagram of the main cross-sectional structure of the sampler in Example 1.

[0023] Attachment Figure 3 This is a circuit block diagram of Example 1.

[0024] Attachment Figure 4 This is a schematic diagram of the main cross-sectional structure of the coil in Example 2.

[0025] The codes in the accompanying drawings are: 1 is a water bath, 2 is a coil, 3 is a sampling tube, 4 is a multiphase flow pump, 5 is an ultrasonic measurement module, 6 is an ultrasonic transmitting probe, 7 is an ultrasonic receiving probe, 8 is a temperature regulating device, 9 is a radiator, 10 is a sampler, 11 is a sampling valve, 12 is a sample outlet tube, 13 is a discharge valve, 14 is a one-way valve, 15 is a first pressure sensor, 16 is a second pressure sensor, 17 is a sampling branch pipe, 18 is a temperature sensor, 19 is a protective shell, and 20 is an insulation layer. DETAILED DESCRIPTION

[0026] The present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions.

[0027] In the present invention, for the convenience of description, the relative position relationship of each component is described based on the Figure 1 For example, the positional relationships of front, back, up, down, left, and right are determined according to the layout directions of the drawings in the specification.

[0028] The present invention will be further described below in conjunction with the embodiments and accompanying drawings:

[0029] Example 1: As shown in the attached Figure 1 、 2 As shown in Figure 3, the test device for the minimum flowable temperature of the mixed pipeline includes a water bath 1, a coil 2, a first pressure sensor 15, a second pressure sensor 16, an ultrasonic measurement module 5, a temperature adjustment device 8 and a control unit. Several coils 2 are wound in the water bath 1. The first end of the coil 2 is sealed and passes through the left rear part of the water bath 1, and the second end of the coil 2 is sealed and passes through the left front part of the water bath 1. A one-way valve 14 is provided on the coil 2. An ultrasonic transmitting probe 6 and an ultrasonic receiving probe 7 are symmetrically installed on the outer side of the coil 2 corresponding to the position between the one-way valve 14 and the discharge valve 13. The lower end of the first pressure sensor 15 is sealed and passes through the water bath 1. The upper side is installed on the coil 2 between the one-way valve 14 and the left inner wall of the water bath 1. The lower end of the second pressure sensor 16 is sealed and passed through the upper side of the water bath 1 and is installed on the coil 2 between the ultrasonic transmitting probe 6 and the left inner wall of the water bath 1. A radiator 9 is provided in the center of the coil 2, and the radiator 9 is connected to the temperature regulating device 8. A temperature sensor 18 is installed on the upper right side of the water bath 1. The ultrasonic transmitting probe 6 and the ultrasonic receiving probe 7 are both connected to the ultrasonic measuring module 5. The control unit is respectively connected to the first pressure sensor 15, the second pressure sensor 16, the ultrasonic measuring module 5, the temperature sensor 18 and the temperature regulating device 8.

[0030] The ultrasonic transmitting probe 6 is a known technology, such as a t40-16 ultrasonic transmitting probe, the ultrasonic receiving probe 7 is a known technology, such as a r40-16 ultrasonic receiving probe, the ultrasonic transmitting probe 6 and the ultrasonic receiving probe 7 are sealed and installed outside a waterproof shell, the ultrasonic measuring module 5 is a known technology, such as a TDC-GP2 high-precision time converter, the ultrasonic transmitting probe 6, the ultrasonic receiving probe 7 and the temperature adjusting device 8 are located in the water bath box 1, the first pressure sensor 15 and the second pressure sensor 16 are known technologies, such as a PXW intelligent pressure transducer controller, the pressure sensor has a range of 0MPa-60MPa and an accuracy level of 0.1, the control unit is a known technology, such as a programmable controller, the temperature sensor 18 is a known technology, such as a PYR-Exd-Dp series digital temperature sensor 18, the temperature sensor 18 has a range of -50℃-260℃ and an accuracy of ±0.1℃, the radiator 9 is a known technology, such as a finned tube radiator, the temperature adjusting device 8 is a known technology, such as a programmable constant temperature and humidity test box with a TEMI-880 intelligent liquid crystal touch mode programmable controller, the outlet of the radiator 9 is fixedly communicated with the inlet of the temperature adjusting device 8, the inlet of the radiator 9 is fixedly communicated with the outlet of the temperature adjusting device 8, the cold source of the temperature adjusting device 8 circulates in the radiator 9, thereby reducing the temperature in the water bath box 1, the maximum bearing pressure of the coil pipe 2 is 2MPa, the diameter of the coil pipe 2 is 25mm, the coil pipe 2 is coiled four times in the water bath box 1 and forms a horizontal vortex, and the center line of the outermost circle forms a circle with a radius of 0.5m.

[0031] In use, the water bath box 1 is filled with a mixture of water and methanol which does not freeze below zero degrees Celsius, the coil pipe 2 is immersed in the mixture of water and methanol, the temperature adjusting device 8 is arranged to provide cold energy to the mixture in the water bath box 1, thereby reducing the temperature of the mixture, the ultrasonic transmitting probe 6 and the ultrasonic receiving probe 7 are symmetrically arranged along the center axis of the coil pipe 2, the ultrasonic transmitting probe 6, the ultrasonic receiving probe 7 and the ultrasonic measuring module 5 are arranged to measure the ultrasonic propagation time of the fluid in the coil pipe 2, the one-way valve 14 is arranged to ensure that all the fluid flows in one direction, and the minimum flowable temperature of the multiphase flow under multiple influencing factors can be accurately measured.

[0032] During the test, the first and second ends of the coil 2 are connected to the oil outlet pipeline of a single well, and the temperature regulating device 8 lowers the temperature of the mixed liquid. When the fluid in the coil 2 is lower than the design temperature, the oil-gas-water mixture solidifies. When the oil-gas-water mixture solidifies, the propagation speed of the ultrasonic wave in the multiphase fluid will change, causing the propagation time of the ultrasonic wave from the ultrasonic transmitting probe 6 to the ultrasonic receiving probe 7 to change. The control unit obtains the temperature data of the temperature sensor 18 at this time as T1. When the readings of the first pressure sensor 15 and the second pressure sensor 16 suddenly change, it indicates that the pressure loss along the mixed pipeline increases sharply, indicating that the flow condition of the mixed fluid at the corresponding temperature deteriorates. The control unit records the temperature data of the temperature sensor 18 at this time as T2. The smaller value of T1 and T2 is the minimum flowable temperature of the mixed pipeline.

[0033] The above-mentioned test device for the minimum flowable temperature of the mixed pipeline can be further optimized and / or improved according to actual needs:

[0034] Example 2: As an optimization of the above example, as shown in the attached Figure 1 、 4 As shown, it also includes a multiphase flow pump 4 and a sampler 10. The outlet of the multiphase flow pump 4 is fixedly connected to the first end of the coil 2. A sampling tube 3 is fixedly connected between the inlet of the multiphase flow pump 4 and the tubular structure sampler 10. A sampling valve 11 is installed on the sampling tube 3. The second end of the coil 2 is fixedly connected to a sample outlet tube 12. A discharge valve 13 is installed on the sample outlet tube 12. The multiphase flow pump 4 is connected to the control unit.

[0035] The first pressure sensor 15 is close to the multiphase flow pump 4, and the second pressure sensor 16 is close to the discharge valve 13. A sampler 10 is installed on the oil outlet pipeline of a single well, and the outlet end of the sampling pipe 12 is fixedly connected to the oil outlet pipeline, so that the oil, gas and water mixture sample flows into the coil 2 through the sampling pipe 3. The sampling valve 11 can control the flow rate of the sampling fluid. After the test is completed, the mixed fluid is directly transported back to the oil outlet pipeline through the sampling pipe 12, so as not to waste the tested fluid and to avoid polluting the environment after the tested fluid is discharged. The oil, gas and water mixture flows into the sampling pipe 3, and the multiphase flow pump 4 continuously pumps the oil, gas and water mixture into the coil 2, forming a sustainable flow mixed fluid loop from the sampler 10 to the sampling pipe 12. By controlling the speed of the multiphase flow pump 4 by the control unit, a multiphase flow fluid with a set shear rate can be provided, thereby improving the accuracy of the measurement.

[0036] Example 3: As an optimization of the above embodiment, as shown in the attached Figure 1 、 4As shown, four internally and externally connected sampling holes are evenly spaced along the circumference of the central outer portion of the sampler 10. A sampling branch pipe 17 is fixedly connected between each sampling hole and the end of the sampling tube 3 away from the multiphase flow pump 4. As needed, the four sampling branches 17 are fixedly connected to the sampling tube 3 via a conventional five-way joint. This arrangement allows samples of the oil-gas-water mixture to be obtained without changing the oil-gas-water ratio. After the test is completed, the mixed fluid is directly transported back to the oil outlet pipeline through the sample outlet pipe 12, thus avoiding waste of the tested fluid and causing environmental pollution.

[0037] Example 4: As an optimization of the above embodiment, as shown in the attached Figure 1 As shown, a protective shell 19 is provided on the outside of the water bath 1, and an insulation layer 20 is placed between the inside of the protective shell 19 and the inside of the water bath 1. The insulation layer 20 is made of polyurethane, as required. The provision of the protective shell 19 not only prevents damage to the insulation layer 20 but also facilitates its installation. The provision of the insulation layer 20 also reduces the rate of temperature change in the water bath 1, thereby maintaining a stable temperature within the water bath 1.

[0038] Example 5: As shown in the attached Figure 1 、 2 As shown in Figures 3 and 4, a method for using a device for testing the minimum flowable temperature of a mixed pipeline is characterized by comprising the following steps:

[0039] Step 1: Close the sampling valve 11 and the discharge valve 13, and connect the sampler 10 and the sample outlet pipe 12 to the oil outlet pipeline of the single well;

[0040] Step 2: Add a mixture of water and methanol into the water bath 1;

[0041] Step 3: Open the sampling valve 11 and the discharge valve 13, start the multiphase flow pump 4, control the speed of the multiphase flow pump 4, and deliver the fluid with the set shear rate into the coil 2;

[0042] Step 4: The control unit controls the temperature regulating device 8 to operate so that the temperature of the mixed liquid in the water bath 1 decreases at a set rate;

[0043] Step 5: The ultrasonic measurement module 5 transmits ultrasonic waves into the coil 2 via the ultrasonic transmitting probe 6. The ultrasonic receiving probe 7 receives the ultrasonic waves transmitted by the ultrasonic transmitting probe 6 and feeds them back to the ultrasonic measurement module 5. The ultrasonic measurement module 5 measures the propagation time of the ultrasonic waves in the mixed fluid in the coil 2. When the propagation time of the ultrasonic waves from the ultrasonic transmitting probe 6 to the ultrasonic receiving probe 7 changes, the temperature sensor 18 data at this time is T1;

[0044] When the data of the first pressure sensor 15 and the second sensor suddenly change, the data of the temperature sensor 18 at this time is T2;

[0045] The smaller value of T1 and T2 is the minimum flowable temperature of the multiphase pipeline.

[0046] The temperature of the mixed liquid in the water bath box 1 is reduced at a rate of 0.1℃ / min.

[0047] Specifically, the step one is: adding pure water from the sampler 10, opening the multiphase flow pump 4 and the relief valve 13 to flush the coil pipe 2, after flushing, dry nitrogen is introduced, the liquid in the coil pipe 2 is discharged and dried, the sampling valve 11 and the relief valve 13 are closed, and the sampler 10 and the sample outlet pipe 12 are fixedly communicated with the oil outlet pipeline of the single well.

[0048] The data acquisition frequency of the temperature sensor 18, the first pressure sensor 15 and the second pressure sensor 16 is 1Hz, the temperature of the mixed liquid in the water bath box 1 is reduced at a rate of 0.1℃ / min by the temperature adjusting device 8 controlled by the control unit, and the temperature sensor 18 measures the temperature of the mixed liquid in the water bath box 1.

[0049] Before using the testing device of the minimum flowable temperature of the multiphase pipeline, first, check whether the sealing of the pipeline connection is good, test the freezing point of the crude oil according to the standard of GB / T510-2018, add pure water from the sampler 10, open the multiphase flow pump 4 and the relief valve 13 to flush the coil pipe 2, after flushing, dry nitrogen is introduced, the liquid in the coil pipe 2 is discharged and dried; then, the sampling valve 11 and the relief valve 13 are closed, the sampler 10 is installed on the oil outlet pipeline of the single well, and the outlet end of the sample outlet pipe 12 is fixedly communicated with the oil outlet pipeline, so that the oil, gas and water mixture sample can flow into the coil pipe 2 through the sampling pipe 3, the sampling valve 11 can control the flow of the sampling fluid, and after the test is completed, the mixed fluid is directly transported back to the oil outlet pipeline through the sample outlet pipe 12; finally, the mixed liquid of water and methanol is added in the water bath box 1.

[0050] When testing the minimum flowable temperature of the multiphase pipeline, first, the sampling valve 11 and the relief valve 13 are opened, the multiphase flow pump 4 is started, the rotating speed of the multiphase flow pump 4 is controlled, the fluid with a set shear rate is transported into the coil pipe 2, and then the temperature adjusting device 8 reduces the temperature of the mixed liquid.

[0051] When the fluid in the coil pipe 2 is lower than the design temperature, the oil, gas and water mixture is frozen, when the oil, gas and water mixture is frozen, the propagation speed of the ultrasonic wave in the multiphase fluid changes, which causes the propagation time of the ultrasonic wave from the ultrasonic wave emitting probe 6 to the ultrasonic wave receiving probe 7 to change, and the control unit obtains the temperature data of the temperature sensor 18 at this time as T1.

[0052] When the readings of the first pressure sensor 15 and the second pressure sensor 16 suddenly change, it means that the pressure loss along the mixed pipeline increases sharply, which means that the flow condition of the mixed fluid at the corresponding temperature deteriorates. The control unit records the temperature data of the temperature sensor 18 at this time as T2. The smaller value of T1 and T2 is the minimum flowable temperature of the mixed pipeline.

[0053] The empirical formula for calculating the minimum flowable temperature of a single well is determined based on the test data. The quantitative formula between the minimum flowable temperature and the gas-oil ratio, water content, shear rate, and normal crude oil pour point is as follows:

[0054] t=a(T b )×(x c )×(y d )×exp(e×z f )

[0055] Where: t is the pour point, unit is K; T is the pour point of normal crude oil, unit is K; x is the water content; y is the gas-oil ratio; z is the shear rate, unit is s -1 a, b, c, d, e, and f are coefficients. The lowest flowable temperature of mixed crude oil under multiple operating conditions was measured, and the coefficients a, b, c, d, and f were calculated based on multiple experimental data.

[0056] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the requirements of different situations.

Claims

1. A method for using a device for testing the minimum flowable temperature of a mixed pipeline, characterized in that A test device for the minimum flowable temperature of a mixed pipeline includes a water bath, a coil, a first pressure sensor, a second pressure sensor, an ultrasonic measurement module, a temperature regulating device and a control unit. Several coils are wound in the water bath, the first end of the coil is sealed and passes through the left rear portion of the water bath, the second end of the coil is sealed and passes through the left front portion of the water bath, a one-way valve is provided on the coil, and an ultrasonic transmitting probe and an ultrasonic receiving probe are symmetrically installed on the outer side of the coil corresponding to the position between the one-way valve and the discharge valve. The lower end of the first pressure sensor is sealed and passed through the upper side of the water bath and then installed on the coil between the one-way valve and the left inner wall of the water bath. The lower end of the second pressure sensor is sealed and passed through the upper side of the water bath and then installed on the coil between the ultrasonic transmitting probe and the left inner wall of the water bath. A radiator is provided in the center of the coil, the radiator is connected to the temperature regulating device, a temperature sensor is installed on the upper right side of the water bath, the ultrasonic transmitting probe and the ultrasonic receiving probe are both connected to the ultrasonic measurement module, and the control unit is respectively connected to the first pressure sensor, the second pressure sensor, the ultrasonic measurement module, the temperature sensor and the temperature regulating device; The method for using the device for testing the minimum flowable temperature of a mixed pipeline comprises the following steps: Step 1: Close the sampling valve and the discharge valve, and connect the sampler and the sample outlet pipe to the oil outlet pipeline of the single well; Step 2: Add a mixture of water and methanol into the water bath; Step 3: Open the sampling valve and the discharge valve, start the multiphase flow pump, control the speed of the multiphase flow pump, and deliver the fluid with the set shear rate into the coil; Step 4: The control unit controls the temperature regulating device to operate so that the temperature of the mixed liquid in the water bath decreases at a set rate; Step 5: The ultrasonic measurement module transmits ultrasonic waves into the coil through the ultrasonic transmitting probe. The ultrasonic receiving probe receives the ultrasonic waves transmitted by the ultrasonic transmitting probe and feeds them back to the ultrasonic measurement module. The ultrasonic measurement module measures the propagation time of the ultrasonic waves in the mixed fluid in the coil. When the propagation time of the ultrasonic waves from the ultrasonic transmitting probe to the ultrasonic receiving probe changes, the temperature sensor data at this time is T1; When the data of the first pressure sensor and the second sensor suddenly change, the temperature sensor data at this time is T2; The smaller value between T1 and T2 is the minimum flowable temperature of the mixed pipeline.

2. The method for using the device for testing the minimum flowable temperature of a mixed pipeline according to claim 1, characterized in that It also includes a multiphase flow pump and a sampler. The outlet of the multiphase flow pump is fixedly connected to the first end of the coil. A sampling tube is fixedly connected between the inlet of the multiphase flow pump and the tubular structure sampler. A sampling valve is installed on the sampling tube. The second end of the coil is fixedly connected to a sample outlet tube. A discharge valve is installed on the sample outlet tube. The multiphase flow pump is connected to a control unit.

3. The method for using the device for testing the minimum flowable temperature of a mixed pipeline according to claim 2, characterized in that Four internally and externally connected sampling holes are evenly distributed along the circumference of the middle outer side of the sampler. A sampling branch pipe is fixedly connected between each sampling hole and the end of the sampling tube away from the multiphase flow pump.

4. The method for using the device for testing the minimum flowable temperature of a mixed pipeline according to claim 1, 2 or 3, characterized in that A protective shell is provided on the outside of the water bath, and an insulation layer is filled between the inside of the protective shell and the inside of the water bath.

5. The method for using the device for testing the minimum flowable temperature of a mixed pipeline according to claim 1, characterized in that The temperature of the mixed solution in the water bath was decreased at a rate of 0.1°C / min.

6. The method for using the device for testing the minimum flowable temperature of a mixed transportation pipeline according to claim 1 or 5, characterized in that Step one is as follows: add pure water from the sampler, open the multiphase flow pump and the discharge valve to flush the coil, and after flushing, introduce dry nitrogen to drain and dry the liquid in the coil, close the sampling valve and the discharge valve, and fix the sampler and the sample outlet pipe to the oil outlet pipeline of the single well.

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