A method for determining a safe temperature limit of high-water-content thick oil cold transportation

Abstract

The present application belongs to the technical field of oilfield gathering and transportation, and discloses a method for judging the safe temperature limit of cold transportation of high-water-content heavy oil. The steps are as follows: providing expected cold transportation limit for stirring simulation, constant-temperature stable flow of oil and water, oil and water cooling transportation experiment, and pipeline cleaning. The present application solves the defect that the cold transportation temperature judgment basis of the existing flow loop device cannot be applied to heavy oil, and proposes to take the temperature of "simultaneous occurrence of severe oscillation of flow and pressure drop" as the limit of cold transportation temperature. The test method is proved by repeated experiments, and the test deviation is less than 2℃, and the test result is reliable and has repeatability.

Description

Technical Field

[0001] This invention belongs to the field of oilfield gathering and transportation technology, specifically relating to a method for determining the safe temperature limit for cold transportation of heavy oil with high water content. Background Technology

[0002] Heavy oil is characterized by high density, high viscosity, and poor fluidity. Traditional heating methods face difficulties such as high cost, high carbon emissions, and limited economic value. Pumping temperature is a crucial factor affecting the fluidity and economics of crude oil pipeline transportation. Therefore, to transport heavy oil economically, it is essential to reduce heating temperatures and corresponding energy consumption and carbon emissions. As most oilfields enter the mid-to-late stages of development, the large-scale application of waterflooding has made high-water-content heavy oil produced fluids common, providing favorable conditions for low-temperature flow of heavy oil. However, as oil temperature decreases, the reduced fluidity caused by high viscosity, asphaltene deposition, heavy metals, sulfur, and salt content can lead to serious transportation problems and even pipeline blockage. Therefore, it is necessary to conduct research on methods for determining the cold transport temperature limit of high-water-content heavy oil, while ensuring pipeline flow safety, in order to reduce the cost of producing and transporting heavy oil in oilfields.

[0003] The stirred tank simulation method is currently the most widely used and convenient method for determining the temperature limits of cold transport. The main components of the device include a simulated tank, a stirrer, and a temperature-controlled water bath. The device uses stirring and shearing as a bridge to simulate oil-water flow in a pipeline, and directly reflects the deterioration of cold transport flow conditions by the abrupt change in the quality of crude oil adhering to the tank wall. The key to this method is finding the "abrupt change point" in the quality of adhering to the wall, and it has been successfully applied in high-water-content, waxy crude oil production blocks in Daqing Oilfield, Jilin Oilfield, Jiangsu Oilfield, North China Oilfield, Changqing Oilfield, and Qinghai Oilfield. However, this device is mainly designed for the "gelling" structural characteristics of waxy crude oil, and has unavoidable drawbacks when applied to the adhering wall of heavy oil: First, the structure of heavy oil at low temperatures exhibits the characteristics of "continuous shear flow without solidification," which makes it difficult to define the quality of heavy oil adhering to the simulated tank wall, resulting in significant testing errors. Second, the adhering wall pattern of heavy oil exhibits a "gradual" characteristic of "the quality of adhering to the wall continuously increases as the temperature gradually decreases," without a clear "abrupt change point." Therefore, in response to this pattern, the determination of the cold transport temperature limit for heavy oil cannot be simply copied from that for waxy crude oil. Instead, a different determination method should be explored, taking into account the unique properties of heavy oil itself.

[0004] Patent CN115076607A discloses a cold-extracted extra-heavy oil gathering and transportation process that organically combines physical and chemical viscosity reduction methods. It employs a physical viscosity reduction method (adding a diluent) and a chemical viscosity reduction method (adding a viscosity reducer). Using these two methods in combination significantly reduces the amount of diluent needed, lowering the original heavy oil to diluent ratio from 1:2.5 to 1:0.5–1.2. Furthermore, when using a viscosity reducer for chemical viscosity reduction, compared to existing methods that rely solely on the viscosity reducer and require a viscosity reduction rate of around 90%, this application, combined with physical viscosity reduction, only requires controlling the viscosity reduction rate to 40%–80%, greatly reducing the amount of viscosity reducer used. Additionally, the viscosity-reduced heavy oil produced by this method has lower temperature requirements, eliminating the need for underground insulation and transportation measures, significantly reducing heavy oil extraction costs and solving the problem of difficult gathering and transportation of cold-extracted extra-heavy oil. However, the patent does not address how to determine the temperature range for gathering and transportation. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a method for determining the safe temperature limit for cold transport of heavy oil with high water content, quantifying the criterion of "simultaneous violent oscillation of flow differential pressure and flow rate". This method is better suited to the structural characteristics of heavy oil, such as "continuous shear flow without solidification" and "gradual" wall adhesion, and the test judgment criteria are reliable, with better test repeatability than the stirred tank method.

[0006] The above-mentioned objective of this invention is achieved through the following technical solution: a method for determining the safe temperature limit for cold transport of heavy oil with high water content, comprising the following steps:

[0007] (1) Stirring simulation provides the expected cold transport limit: The oil-water mixture with the same experimental conditions as the ring is placed in the stirring tank, the temperature is controlled and stirred, and then the temperature is controlled to drop at a constant speed to observe the change of stirring torque. The temperature at which the torque fluctuates abnormally and cannot be read is recorded as T1.

[0008] (2) Oil-water constant temperature stable flow: Dehydrated crude oil and water are poured into an oil-water mixing tank to form an oil-water mixture with a water content of φ1. The temperature is controlled at T1. After thorough stirring, the mixture is pumped into the experimental loop. The flow rate is controlled, and the temperature and differential pressure changes are monitored. The mixture is run until the temperature and differential pressure are stable.

[0009] (3) Oil-water cooling and transport experiment: The oil-water mixture in step (2) is cooled at a constant speed, the flow rate and rotation speed are controlled, and the changes in flow rate and differential pressure are monitored until the flow rate and pressure drop fluctuate violently at the same time. The temperature at this time is determined to be the safe temperature limit.

[0010] (4) Pipeline cleaning: Turn off the pump to end the experiment and clean the pipeline.

[0011] Further, the specific steps of Step 1 are as follows: Prepare an oil-water mixture in the stirring tank under the same conditions as in the loop experiment; Place a stirrer with the functions of adjusting the stirring speed and reading the stirring torque in the stirring tank, control the temperature by connecting to a water bath, and keep the stirring speed constant; Select a relatively high temperature T0 as the starting temperature of stirring, and control the constant cooling rate of the water bath; During the cooling process, observe the change of the stirring torque. If abnormal fluctuations and oscillations of the torque are observed, a stable value cannot be read, and a significant thick viscous oil layer adheres to the stirring paddle, record this temperature as the starting temperature T1 for the subsequent cooling of the loop experiment.

[0012] Further, the specific steps of Step 2 are as follows: Pour a certain amount of dehydrated crude oil and water into the oil-water mixing tank according to the water cut φ1 of the oil-water mixture. At the same time, turn on the circulating water bath, heat and keep warm the oil-water mixing tank and the pipeline respectively to make their temperatures stable at T1. After the temperature in the oil-water mixing tank is stable at T1, turn on the motor of the oil-water mixing tank and set the frequency of the stirring paddle to fully stir the oil-water mixture; Then open the outlet valve to make the oil and water evenly mix and enter the pipeline; Turn on the screw pump to pressurize and pump the oil-water mixture into the experimental loop. At the same time, adjust the motor frequency of the screw pump to make the reading of the volume flowmeter stable at Q1, so as to control the flow rate of the oil-water mixture in the pipeline to be v1; Use the temperature sensors and differential pressure sensors along the loop to monitor the changes in temperature and differential pressure, and run until the temperature and differential pressure are stable.

[0013] Further, the specific steps of Step 3 are as follows: Adjust the temperature of the circulating water bath to cool the oil-water mixture. During the cooling process, adjust the speed of the screw pump every 1 °C to make the flow rate stable near Q1, and monitor the changes in the flow rate Q and the differential pressure P; If the flow rate Q can be stable within the range of Q1×(1±2%) at the temperature T2, and there is no significant abnormal fluctuation in the pressure drop. This indicates that the flow state is good under this condition (φ1, v1, T2), and the viscous oil and water mixture can still be cooled and transported continuously. Continue to lower the test temperature to T3 (T3 < T2), and repeat the steps of flow rate adjustment and differential pressure monitoring. Until both the flow rate and the pressure drop show violent fluctuations, the flow rate cannot be stable within the range of Q1×(1±2%), and the pressure drop shows violent oscillations. That is, the pipe flow cannot maintain stability under this flow condition. At low temperatures, the adhesion of viscous oil and flow blockage cause an unstable working condition of oil-water slug flow in the pipeline, showing violent fluctuations in the flow rate and the pressure drop. Through the above experimental phenomena, determine that T3 is the cold transportation safety temperature limit of the high-water-cut viscous oil gathering and transportation pipeline under this condition (φ1, v1). When the temperature is above this value, the fluctuations of the flow rate and the pressure drop in the pipeline are stable, and it will not cause an increase in the back pressure at the wellhead on site, ensuring the flow safety of the gathering and transportation pipeline. Therefore, it is recommended to determine the cold transportation safety temperature limit of high-water-cut viscous oil not lower than T3 by this method.

[0014] Furthermore, step 4 specifically involves: after the flow temperature of the oil-water mixture drops to the preset temperature mentioned above, turning off the pump to end the experiment. The pipeline is then cleaned using an air compressor.

[0015] Furthermore, the oil-water mixing tank has a volume of 50L and is divided into an inner tank and an insulated outer tank. The insulated outer tank is connected to a circulating water bath, and the temperature of the oil-water mixture inside the tank is controlled by the water bath temperature. The top of the inner tank is equipped with a motor and a stirring paddle, and the rotation speed of the stirring paddle is controlled by the motor. The motor frequency adjustment range is 5-50HZ.

[0016] Furthermore, the screw pump is a CG type stainless steel screw pump with a displacement of 5m³ / h. 3 / h, head is 50m, rated power is 2.2KW.

[0017] Furthermore, the volumetric flow meter is a gear volumetric flow meter with an accuracy of 0.5 and a flow range of 150-3000 L / H.

[0018] Furthermore, the flow loop pipe is made of stainless steel and has an external water bath sleeve connected to the circulating water bath to control the temperature of the flow inside the pipe. The total length of the pipe is 12m and the inner diameter is 30mm. It includes a 1m long test pipe section. Temperature sensors and differential pressure sensors are installed at both ends of the test pipe section to monitor the temperature and differential pressure changes of the test pipe section.

[0019] Furthermore, the circulating water bath is a HAKKEAC200 water bath with a temperature control range of 5-90℃ and a temperature control accuracy of 0.01℃.

[0020] Furthermore, the air compressor is model OTS-1100X2, with a rated displacement of 200L / min and a rated exhaust pressure of 0.7MPa, and is used for air-driven cleaning of pipelines.

[0021] The connection method between components in this invention is as follows:

[0022] The flow circulation system consists of two parts: an in-pipe flow circulation system and a casing flow circulation system. The in-pipe flow circulation system includes an inner tank of the oil-water mixing tank, a screw pump, a volumetric flow meter, and test pipe sections, all connected by stainless steel pipes. The flow components are horizontally installed on the same platform to ensure horizontal fluid flow within the pipe. The casing flow circulation system comprises an outer tank of the oil-water mixing tank, an outer tank of the flow pipeline, and a circulating water bath. The components are connected by 10mm latex tubing. One circulating water bath controls the temperature of the outer tank, and the other controls the temperature of the pipeline.

[0023] The advantages of this invention compared to the prior art are:

[0024] (1) The method for determining the safe temperature limit for cold transport of heavy oil with high water content provided by the present invention simulates the pipeline flow conditions more closely than those of a stirred tank by constructing an experimental loop. At the same time, it uses differential pressure changes and flow rate changes to define the deterioration of the cold transport conditions, which solves the problem that the adhesion quality of heavy oil and the "abrupt point" of wall adhesion are difficult to define on the stirred tank, and the method for determining the temperature limit for cold transport of heavy oil is unclear.

[0025] (2) This invention improves the problem that the existing flow loop device does not adequately consider the cold transport temperature limit of heavy oil. In view of the structural characteristics of heavy oil, which is "continuous shear flow and does not solidify" and the "gradual" wall adhesion characteristics, a method for judging the cold transport temperature limit based on the flow condition and pressure drop change is proposed, and the evaluation index is quantified.

[0026] (3) This invention addresses the limitation of existing flow loop devices in determining cold transport temperature for heavy oil, proposing to use the temperature at which "both flow rate and pressure drop simultaneously exhibit violent fluctuations" as the boundary for cold transport temperature. This testing method has been proven through repeated experiments to have a test deviation of less than 2℃, and the test results are reliable and repeatable. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] Figure 1 This is a schematic diagram of the device structure used in the method for determining the safe temperature limit of cold transport of high water content heavy oil according to the present invention;

[0029] Figure 2 This is the result of multiple repetitions of testing the cold transport temperature limit of heavy oil in the embodiment using a stirring tank.

[0030] Figure 3 These are the results of three repeated experiments testing the temperature limits of heavy oil in the flow loop device in the embodiments.

[0031] In the diagram: 1. Oil-water mixing tank; 2. Screw pump; 3. Volumetric flow meter; 4. Test pipe section; 5. Circulating water bath; 6. Air compressor; 7. Differential pressure sensor; 8. Temperature sensor; 9. Ball valve. Detailed Implementation

[0032] The present invention is described in detail below through specific embodiments, but this does not limit the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can all be obtained commercially.

[0033] Example 1

[0034] A method for determining the safe temperature limit for cold transport of heavy oil with high water content

[0035] It includes four parts: (1) Stirring simulation to provide the expected cold transportation limit; (2) Constant temperature and stable flow of oil and water; (3) Experiment on cooling and transportation of oil and water; (4) Pipeline cleaning. The specific test steps are as follows:

[0036] (1) Stirring simulation to provide the expected cold transportation limit. Configure 120 mL of oil-water mixture with the same conditions (the same oil-water ratio and the same temperature) as the loop experiment in the stirring tank. Place a stirrer with the functions of adjusting the stirring speed and reading the stirring torque in the stirring tank, and control the temperature by connecting it to a water bath. The stirring speed is kept constant at 1000 rpm. Select a relatively high temperature T0 as the starting temperature of stirring, and control the cooling rate of the water bath at 0.5 °C / min. Observe the change of the stirring torque during the cooling process. When it is observed that the torque shows abnormal fluctuations and oscillations, a stable value cannot be read, and there is a significant thick sticky oil layer adhering to the stirring paddle, record this temperature as the starting temperature T1 for the subsequent cooling of the loop experiment.

[0037] (2) Constant temperature and stable flow of oil and water. According to the water content of the oil-water mixture Pour a total of 30 L of dehydrated crude oil and water into the oil-water mixing tank 1. At the same time, turn on 2 circulating water baths 5 to heat and keep warm the oil-water mixing tank and the pipeline respectively, so that the temperature is stabilized at T1. After the temperature in the oil-water mixing tank is stabilized at T1, turn on the motor of the tank and set the frequency of the stirring paddle at 50 HZ to fully stir the oil-water mixture for 10 min. Then open the tank outlet valve 1 to make the oil and water evenly mix and enter the pipeline. Turn on the screw pump 2 to pressurize and pump the oil-water mixture into the experimental loop. At the same time, adjust the motor frequency of the screw pump to make the reading of the volume flowmeter 3 stable at Q1, so as to control the flow rate of the oil-water mixture in the pipeline at v1. Use the temperature sensors and differential pressure sensors along the loop to monitor the changes of temperature and differential pressure, and run until the temperature and differential pressure are stable.

[0038] (3) Experiment on cooling and transportation of oil and water. Adjust the temperatures of the 2 circulating water baths connected to the tank and the pipeline to cool the oil-water mixture. During the cooling process, adjust the pump speed every 1 °C to make the flow rate stable near Q1, and monitor the changes of the flow rate Q and the differential pressure P. If at the temperature T2, the flow rate Q can be stabilized within the range of Q1×(1±2%), and there is no significant abnormal fluctuation in the pressure drop. This indicates that under this condition The flow state is good, and the heavy oil and water mixture can still continue to be cooled and transported. Continue to lower the test temperature to T3 (T3 < T2), and repeat the steps of flow rate adjustment and differential pressure monitoring. Until both the flow rate and the pressure drop show violent fluctuations, the flow rate cannot be stabilized within the range of Q1×(1±2%), and the pressure drop shows violent oscillations. That is, the pipe flow cannot maintain stability under this flow condition. At low temperatures, the adhesion of heavy oil and the flow blockage cause unstable working conditions of oil-water slug flow in the pipeline, showing violent fluctuations in the flow rate and the pressure drop.

[0039] Based on the above experimental phenomena, it is determined that T3 is the value under this condition. The safe temperature limit for cold transport of high water-content heavy oil gathering and transportation pipelines. Above this temperature, the flow rate and pressure drop fluctuations in the pipeline are stable, preventing an increase in the current wellhead back pressure and ensuring the flow safety of the gathering and transportation pipeline. Therefore, it is recommended to use this method to determine that the safe temperature limit for cold transport of high water-content heavy oil is not lower than T3.

[0040] (4) Pipeline cleaning. After the flow temperature of the oil-water mixture drops to the preset temperature mentioned above, turn off the pump to end the experiment. Then clean the pipeline with an air compressor.

[0041] Subsequently, the flow conditions were changed (the water content of the oil-water mixture). By repeating the above experimental steps (and mixing flow rate v), the safe temperature limits for cold transport of heavy oil with high water content under different flow conditions were obtained.

[0042] Example 2

[0043] For crude oil (pour point 8℃) from a certain block in the Liaohe River basin, the flow conditions were tested at a water content of 80% and a flow velocity of 0.5 m / s, and three repeatable experiments were conducted. The experimental procedures are as described above, and the results are shown in the attached figure. Figure 3 As shown.

[0044] In all three experiments, the oil samples exhibited abnormal flow conditions at low temperatures. Taking the first experiment as an example, within the temperature range of 50-45℃, the flow pressure drop showed a slow upward trend, while the flow rate remained within the range of 1250-1300 L / h (standard operating condition flow rate 1272 × (1 ± 2%)). This indicates that within this temperature range, the increase in flow pressure drop was mainly due to the increase in viscosity of heavy oil as the temperature decreased, but water remained the external phase of the flow, and crude oil did not adhere extensively to the pipeline, causing drastic fluctuations in flow rate. Within the temperature range of 45-36℃, the flow pressure drop showed slight fluctuations, but no obvious upward trend; in fact, the flow pressure drop even decreased slightly. The flow rate remained within approximately 2% of the normal flow rate, and the flow conditions did not deteriorate significantly. During this stage, as the temperature decreased, the adhesion of crude oil to the pipeline intensified, but water also had a relatively strong ability to remove heavy oil. Heavy oil continuously adhered to and was removed from the pipeline, causing slight fluctuations in the flow pressure drop, but the overall flow conditions were still dominated by water. When the temperature is below 36℃, both pressure drop and flow rate exhibit violent fluctuations. The pressure drop rises rapidly with temperature changes and then falls back, with the amplitude of the flow rate mostly exceeding the normal fluctuation range of 2%. This phenomenon indicates that the adhesion of heavy oil in the pipeline has worsened, causing intermittent oil-water flow, oil-water blockage, and a thick layer of adhesion to the pipeline walls, resulting in violent fluctuations in flow rate and differential pressure.

[0045] Therefore, this phenomenon has relatively clear criteria for judgment, which can be obtained from the apparatus and method of this invention. Furthermore, the criteria for determining the safe temperature limit for cold transport of high-water-content heavy oil are repeatable. Figure 3 The three repeated experiments showed that although the changes in flow pressure drop and flow rate fluctuations had some differences, the temperature limits were 36℃, 35℃, and 35℃ respectively. The overall differences were small, and the criteria for judgment were reliable.

[0046] The embodiments described above are merely preferred embodiments of the present invention, and not all feasible embodiments of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A method for determining the safe temperature limit for cold transport of heavy oil with high water content, characterized in that, The steps are as follows: S1. Stirring simulation provides the expected cold transport limit: The oil-water mixture with the same experimental conditions as the ring track is placed in the stirring tank, the temperature is controlled and stirred, and then the temperature is controlled to drop at a constant rate to observe the change of stirring torque. The temperature at which the torque fluctuates abnormally and cannot be read as T1 is recorded. S2. Oil-water constant temperature stable flow: Dehydrated crude oil and water are poured into an oil-water mixing tank to form an oil-water mixture with a water content of φ1. The temperature is controlled at T1. After thorough stirring, the mixture is pumped into the experimental loop. The flow rate is controlled, and the temperature and differential pressure changes are monitored. The mixture is run until the temperature and differential pressure are stable. S3. Oil-water cooling and transport experiment: The oil-water mixture in step S2 is cooled at a constant rate, the flow rate and rotation speed are controlled, and the changes in flow rate and differential pressure are monitored until the flow rate and pressure drop fluctuate violently at the same time. The temperature at this time is determined to be the safe temperature limit. S4. Pipeline cleaning: Turn off the pump to end the experiment and clean the pipeline.

2. The method for determining the safe temperature limit for cold transport of heavy oil with high water content according to claim 1, characterized in that, Step S1 specifically involves: preparing an oil-water mixture under the same conditions as the loop experiment in a mixing tank; placing a stirrer with stirring speed adjustment and stirring torque reading functions in the mixing tank, controlling the temperature by connecting it to a water bath, and keeping the stirring speed constant; selecting a higher temperature T0 as the stirring start temperature, and controlling the water bath cooling rate to be constant; observing the change in stirring torque during the cooling process, and if abnormal fluctuations and oscillations in the torque are observed, and a stable value cannot be read, and a significant thick layer of sticky oil adheres to the stirring paddle, recording this temperature as the starting temperature T1 for subsequent loop experiment cooling.

3. The method for determining the safe temperature limit for cold transport of heavy oil with high water content according to claim 1, characterized in that, The specific steps of step S2 are as follows: according to the water content φ1 of the oil-water mixture, a certain amount of dehydrated crude oil and water are poured into the oil-water mixing tank, and at the same time, the circulating water bath is turned on to heat and keep the oil-water mixing tank and pipeline warm, so that the temperature is stabilized at T1. After the temperature inside the oil-water mixing tank stabilizes at T1, turn on the motor of the oil-water mixing tank and set the frequency of the stirring paddle to fully stir the oil-water mixture; then open the outlet valve to allow the oil and water to mix evenly and enter the pipeline; turn on the screw pump to pressurize the oil-water mixture and pump it into the experimental loop, while adjusting the motor frequency of the screw pump to stabilize the reading of the volumetric flow meter at Q1, thereby controlling the flow rate of the oil-water mixture in the pipeline to v1; use temperature sensors and differential pressure sensors along the loop to monitor temperature and differential pressure changes, and run until the temperature and differential pressure stabilize.

4. The method for determining the safe temperature limit for cold transport of heavy oil with high water content according to claim 1, characterized in that, Step S3 specifically involves: adjusting the temperature of the circulating water bath to cool the oil-water mixture; adjusting the screw pump speed every 1°C during the cooling process to stabilize the flow rate around Q1, and monitoring the changes in flow rate Q and differential pressure P; if the flow rate Q can be stabilized within the range of Q1×(1±2%) at temperature T2, and the pressure drop does not show significant abnormal fluctuations, it indicates that the flow state is good under φ1, v1, and T2 conditions, and the heavy oil-water mixture can continue to be cooled and transported; further reducing the test temperature to T3, repeating the flow rate adjustment and differential pressure monitoring steps until both the flow rate and pressure drop fluctuate drastically, and the flow rate cannot be stabilized within Q1×(1±2%). Within the range of (1±2%), the pressure drop exhibits severe fluctuations, indicating that the pipeline flow cannot remain stable under these conditions. At low temperatures, the adhesion and flow stagnation of heavy oil cause unstable conditions of oil-water blockage in the pipeline, resulting in severe fluctuations in flow rate and pressure drop. Based on the above experimental phenomena, it is determined that T3 is the safe temperature limit for cold transportation of high water-content heavy oil gathering and transportation pipelines under φ1 and v1 conditions. Above this temperature, the flow rate and pressure drop fluctuations in the pipeline are stable and will not lead to an increase in the current back pressure at the wellhead, thus ensuring the flow safety of the gathering and transportation pipeline. Therefore, it is recommended that this method be used to determine that the safe temperature limit for cold transportation of high water-content heavy oil is not lower than T3.

5. The method for determining the safe temperature limit for cold transport of heavy oil with high water content according to claim 1, characterized in that, Specifically, step S4 involves: when the flow temperature of the oil-water mixture drops to the preset temperature, turning off the pump to end the experiment; and cleaning the pipeline with an air compressor.

6. The method for determining the safe temperature limit for cold transport of heavy oil with high water content according to claim 1, characterized in that, The oil-water mixing tank is divided into an inner tank and an insulated outer tank. The insulated outer tank is connected to a circulating water bath, and the temperature of the oil-water mixture inside the tank is controlled by the temperature of the water bath. The top of the inner tank is equipped with a motor and a stirring paddle. The rotation speed of the stirring paddle is controlled by the motor, and the motor frequency adjustment range is 5-50 Hz.

7. The method for determining the safe temperature limit for cold transport of heavy oil with high water content according to claim 1, characterized in that, The volumetric flow meter is a gear volumetric flow meter with a flow range of 150-3000 L / H.

8. The method for determining the safe temperature limit for cold transport of heavy oil with high water content according to claim 1, characterized in that, The flow loop pipe is made of stainless steel and has an external water bath sleeve connected to the circulating water bath to control the temperature of the flow inside the pipe.

9. The method for determining the safe temperature limit for cold transport of heavy oil with high water content according to claim 1, characterized in that, The circulating water bath is a HAKKEAC200 water bath with a temperature control range of 5-90℃.

10. The method for determining the safe temperature limit for cold transport of heavy oil with high water content according to claim 1, characterized in that, The air compressor, model OTS-1100X2, is used for air-driven cleaning of pipelines.

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