Heavy oil wall surface adhesion quality evaluation device and method

Abstract

The invention discloses a thick oil wall surface adhesion quality evaluation device and method, thick oil is thick oil with high asphaltene and colloid content, the device comprises: an autoclave which is transversely arranged and is used for filling thick oil to be detected, the autoclave performs periodic swing motion in the test process, and a metal ball which can move freely is arranged in the autoclave; at least one end of the cavity of the high-pressure kettle is arranged in an openable sealing manner; the control unit is used for controlling the temperature of the thickened oil and the gas pressure in the autoclave; and the data acquisition and processing unit is used for acquiring the viscosity of the thickened oil in the autoclave under a certain temperature and pressure environment, the reciprocating motion time data of the metal ball and the adhesion amount of the thickened oil on the wall surface and the surface of the metal ball, and calculating the minimum value of the safe conveying temperature of the thickened oil. The viscosity of fluid at different temperatures, the reciprocating motion time of the metal ball and the adhesion amount of the thick oil on the wall surface are measured, the wall adhesion behavior of the thick oil is evaluated, and the minimum value of the safe conveying temperature of the thick oil is determined according to the temperature of adhesion quality sudden change.

Description

Technical Field

[0001] The invention relates to the technical field of safe transportation of heavy oil, and in particular to a device and method for evaluating the quality of heavy oil wall adhesion. Background Art

[0002] Heavy oil is an important component of global energy. Domestic heavy oil and asphalt account for about 20% of the total proven crude oil. Its notable characteristics are high asphaltene and colloid content, high viscosity and poor fluidity. Heavy oil is greatly affected by temperature, and its viscosity tends to decrease significantly with increasing temperature. It is generally believed that the viscosity of heavy oil is mainly affected by the asphaltene content. Strongly polar asphaltene contains aromatic condensed rings, which can form aggregates under the interaction of hydrogen bonds and π-π bonds, and can associate with colloids to form micelles, which significantly increases the viscosity. The asphaltene content in heavy oil can reach 10% to 30%, which is much greater than conventional crude oil such as waxy oil. At the same time, heavy oil contains oxygen, sulfur, nitrogen, and metal elements such as nickel and vanadium. The presence of heteroatoms can form polar groups such as -OH-, -C=O, -NH- and -S-, thereby enhancing hydrogen bond interactions.

[0003] Due to the high viscosity of heavy oil, it faces many problems in the process of transportation and storage. At present, heavy oil is mainly transported by heating, emulsification, dilution, modification and water. Water transport refers to the process of adding a large amount of low-viscosity water phase to heavy oil to enhance the fluidity of heavy oil. This method has a wide range of applications, simple process and low operating cost. At the same time, during the production and gathering process, heavy oil often has a very high water content, which is equivalent to the form of water transport. The traditional heavy oil transportation temperature needs to be maintained above 3°C above the crude oil pour point, but the presence of water phase significantly changes the fluid composition and flow pattern in the pipe, so that high-water-content heavy oil can also be safely operated below the crude oil pour point. Heavy oil with high asphaltene and colloid content will adhere to the inner wall of the pipeline or device due to its high viscosity during transportation, increasing the operating cost. Since heavy oil is greatly affected by temperature, as the operating temperature decreases, the amount of heavy oil adhering to the inner wall will gradually increase, and the mass will increase when it is below a certain temperature, and it may block the pipeline. Therefore, the lower limit of the safe operation temperature of water-containing heavy oil is often taken as the temperature value when the wall adhesion quality increases sharply, and this is used as the transportation boundary. In order to reduce the energy consumption of heavy oil operation and improve the transportation efficiency of heavy oil while ensuring the safe operation of the pipeline, the temperature and adhesion rate of water-containing heavy oil transportation are currently receiving more and more attention. Researchers are actively evaluating the wall adhesion quality of water-containing heavy oil at different temperatures through various methods, determining the lowest temperature for safe transportation, and achieving economic maximization while ensuring safety.

[0004] At present, the existing technology mainly studies the transportation of water-containing heavy oil through loops or stirred tanks, but the loops are expensive and complicated to operate, making them difficult to promote on a large scale. The stirred tank has attracted widespread attention due to its simple operation, low cost and strong adaptability, but its flow pattern is very different from the actual pipeline transportation, and the presence of the stirring paddle has an adverse effect on the evaluation of the adhesion behavior of heavy oil.

[0005] Therefore, there is an urgent need for a method to measure the adhesion behavior of heavy oil with high asphaltene and colloid content on the inner wall of the pipeline during transportation, and to evaluate the adhesion temperature of heavy oil and its impact on the safe operation of the pipeline. It can not only simulate the actual state of heavy oil fluid in pipeline transportation, but also measure the viscosity of the pipe wall adhesion online and evaluate the adhesion rate of heavy oil on the wall and its impact on pipeline operation by measuring the quality of the adhesion.

[0006] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0007] The object of the present invention is to provide a device and method for evaluating the wall adhesion quality of heavy oil, which can evaluate the wall adhesion behavior of heavy oil by measuring the viscosity of the fluid at different temperatures, the reciprocating motion time of a metal ball and the adhesion amount of heavy oil on the wall, and determine the minimum value of the safe transportation temperature of the heavy oil by the temperature at which the adhesion quality suddenly changes.

[0008] To achieve the above object, according to a first aspect of the present invention, a device for evaluating the wall adhesion quality of heavy oil is provided, wherein the heavy oil is a heavy oil with high asphaltene and colloid content, and the device comprises: an autoclave, which is arranged horizontally and used to load the heavy oil to be tested, and the autoclave performs periodic swinging motion during the test, and a freely movable metal ball is arranged in the autoclave; at least one end of the chamber of the autoclave is an openable sealing arrangement; a control unit, which is used to control the temperature of the heavy oil and the gas pressure in the autoclave; a data acquisition and processing unit, which is used to collect the viscosity of the heavy oil in the autoclave under a certain temperature and pressure environment, the reciprocating motion time data of the metal ball, and the adhesion amount of the heavy oil on the wall and the surface of the metal ball, and calculate the minimum value of the safe transportation temperature of the heavy oil.

[0009] Furthermore, in the above technical solution, the metal ball performs reciprocating swinging motion in the autoclave along with the swinging motion of the autoclave, which is used to shear the heavy oil fluid in the autoclave, and the reciprocating motion time data of the metal ball and the real-time measured heavy oil viscosity data are used to evaluate the impact of the heavy oil on the safe operation of the pipeline.

[0010] Furthermore, in the above technical solution, the amount of heavy oil adhering to the wall and the metal ball surface can be collected by: after the autoclave is depressurized and the oil-water mixture is discharged, the chamber of the autoclave is opened and the heavy oil in the corresponding part is taken out for weighing.

[0011] Furthermore, in the above technical solution, the autoclave may be a stainless steel chamber with end covers provided at both ends for sealing; a metal ball displacement sensor may be provided on the outer wall of the stainless steel chamber, and an online viscometer may be provided on the inner wall of the stainless steel chamber.

[0012] Furthermore, in the above technical solution, the autoclave can drive the rotating wheel through the motor, thereby driving the double-link mechanism to achieve periodic swinging motion; the bottom of the autoclave can be provided with a support seat for supporting the swinging. The double-link mechanism can be provided with multiple connection positions for adjusting the swing amplitude of the autoclave according to the test needs.

[0013] Furthermore, in the above technical solution, the control unit may include: a temperature control subunit, which can control the temperature through a temperature-controlled water bath and a water jacket wrapped around the outer wall of the autoclave, and monitor the temperature of the heavy oil in the autoclave through a temperature sensor; a pressure control subunit, which can provide test gas to the autoclave through a gas tank and a valve and pressurize it to a required pressure, and a gas flow meter may be provided on the gas supply pipeline.

[0014] Furthermore, in the above technical solution, the data acquisition and processing unit can record the collected autoclave temperature, pressure data, intake air flow data, heavy oil viscosity, and reciprocating motion time data of the metal ball, and calculate the minimum temperature for safe transportation of the heavy oil through the collected autoclave swing motion frequency and the total content of heavy oil colloid asphaltene data.

[0015] Furthermore, in the above technical solution, the evaluation device may further include: a liquid discharge unit, which includes a liquid discharge valve, and is used to discharge the oil-water mixture through a liquid discharge pipeline before the heavy oil is weighed.

[0016] Furthermore, in the above technical solution, the swing amplitude of the autoclave can be controlled to be ±30° to ±90°.

[0017] Furthermore, in the above technical solution, the test gas in the gas tank can be methane gas, ethane gas, carbon dioxide gas, natural gas or a mixed gas.

[0018] According to a second aspect of the present invention, a method for evaluating the wall adhesion quality of heavy oil is provided, wherein the heavy oil is a heavy oil with high asphaltene and colloid content, and the method comprises the following steps: A, starting a temperature-controlled water bath and adjusting it to a set temperature; loading the heavy oil to be tested into an autoclave and extracting the residual gas in the autoclave; B, driving the autoclave to perform reciprocating swinging motion while pressurizing and recording the swinging frequency; during the periodic swinging motion of the autoclave, the reciprocating motion of the metal ball exerts shear disturbance on the heavy oil fluid in the autoclave; C, gradually lowering the set temperature through a constant temperature water bath to the test temperature; D. collect and record the pressure, temperature, air intake flow, metal ball reciprocating motion time and viscosity real-time data in the autoclave; E. stop the swinging motion of the autoclave and perform pressure relief treatment, empty the oil-water mixture in the autoclave and scrape and weigh the heavy oil adhering to the inner wall of the autoclave and the metal ball to obtain the adhesion amount; evaluate the impact of heavy oil on the safe operation of the pipeline through the metal ball reciprocating motion time data and viscosity real-time data; calculate the minimum temperature for safe transportation of heavy oil through the swinging frequency of the autoclave and the total content of heavy oil colloid asphaltene data.

[0019] Furthermore, in the above technical solution, the calculation of the minimum temperature for safe transportation of heavy oil can be carried out in the following manner:

[0020]

[0021] Among them, T S The lowest temperature for safe transportation of heavy oil; T G is the condensation point of the heavy oil to be tested; f is the swing frequency of the autoclave, C AR It is the total content of colloid asphaltene in heavy oil.

[0022] Furthermore, in the above technical solution, a cleaning step may be included between step A and step B. The cleaning step may specifically include: washing the metal ball, the autoclave chamber and the end cap with deionized water to remove surface impurities, and then further washing with petroleum ether to remove oil stains.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) The evaluation device and method of the present invention are used to evaluate the adhesion behavior of heavy oil with high asphaltene and colloid content on the inner wall of the pipeline during transportation, evaluate the wall adhesion temperature of the heavy oil and the impact on the safe operation of the pipeline, simulate the shear and flow in the pipeline through the swinging motion of the autoclave and the reciprocating motion of the metal ball in the autoclave, simulate the environment of the fluid in the pipeline through water bath temperature control and pressure regulation, make the heavy oil flow in the autoclave cavity of the evaluation device, measure the reciprocating motion time of the metal ball and the viscosity of the pipe wall adhesion online, so that the adhesion state of the heavy oil to be tested can be jointly evaluated by these two indicators, the evaluation results can be mutually verified, and the data can be more accurate; and the adhesion rate of the heavy oil on the wall and the impact on the pipeline operation can be evaluated by measuring the quality of the adhesion;

[0025] 2) The present invention calculates the minimum temperature for safe transportation of heavy oil through parameters such as the swinging frequency of the autoclave, the total content of colloid asphaltene in the heavy oil, and the pour point of the oil product. By comparing the calculated value with the temperature value of the mass increase of the heavy oil wall (i.e., the experimental measured value), it can be judged that the calculation method of the present invention is relatively close to the measured value. The calculation method adopted by the present invention can be used to predict the impact of heavy oil transportation in actual pipelines;

[0026] 3) The present invention sets a freely movable metal ball in the autoclave, which can not only exert disturbance on the fluid, but also reflect the influence of heavy oil adhesion on the fluid flow through the speed of the metal ball movement. The longer the metal ball reciprocates once, the stronger the adhesion of the heavy oil.

[0027] 4) The evaluation device of the present invention has low equipment investment, simple operation, and small footprint. Compared with the flow loop, it does not require a large amount of temperature control equipment, which greatly saves investment and is conducive to the promotion of the device.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a device for evaluating the wall adhesion quality of heavy oil with high asphaltene and colloid content according to the present invention.

[0030] Figure 2 1 is the adhesion quality curve of water-containing heavy oil on the wall at different temperatures in Example 1 of the present invention.

[0031] Description of main reference numerals:

[0032] 1-gas tank, 2-gas flow meter, 3-inlet valve, 4-fixing bolt, 5-left end cover, 6-nut, 7-pressure sensor, 8-online viscometer, 9-partition, 10-metal ball, 11-vent valve, 12-vacuum valve, 13-vacuum pump, 14-water jacket outlet, 15-water bath inlet pipeline, 16-right end cover, 17-autoclave connecting rod, 18-connecting rod, 19-rotating wheel, 20-motor, 21-temperature-controlled water bath, 22-drain valve, 23-metal ball displacement sensor, 24-autoclave support seat, 25-water jacket, 26-autoclave chamber, 27-water jacket inlet, 28-water bath outlet pipeline, 29-temperature sensor, 30-data acquisition and processing unit, 31-computer. DETAILED DESCRIPTION

[0033] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0034] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0035] In this document, for the convenience of description, spatial relative terms such as "below", "below", "down", "above", "above", "upper", etc. may be used to describe the relationship between one element or feature and another element or feature in the accompanying drawings. It should be understood that the spatial relative terms are intended to include different orientations of the object in use or operation in addition to the orientation depicted in the figure. For example, if the object in the figure is turned over, the element described as being "below" or "below" other elements or features will be oriented "above" the element or feature. Therefore, the exemplary term "below" can include both below and above. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatial relative terms used in this document should be interpreted accordingly.

[0036] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit a specific position or relative relationship. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable.

[0037] like Figure 1As shown, the present invention provides a device for evaluating the wall adhesion quality of heavy oil, and the heavy oil is a heavy oil with high asphaltene and colloid content. Compared with the existing reactor using high-pressure stirring paddle type, the present invention can better simulate the flow environment of the on-site pipeline, and can evaluate the adhesion rate of heavy oil on the wall and the impact on the pipeline operation by measuring the quality of adhesion. The evaluation device at least includes an autoclave, a control unit and a data acquisition and processing unit 30. Among them, the autoclave is arranged horizontally and is used to fill the heavy oil to be tested. During the test, the autoclave performs periodic swinging motion. A freely movable metal ball 10 is arranged in the autoclave. Specifically, the metal ball 10 performs reciprocating swinging motion in the autoclave with the movement of the swinging autoclave, which is used to shear the heavy oil fluid in the autoclave. The reciprocating motion time data of the metal ball and the real-time measured heavy oil viscosity data can be used together to evaluate the impact of heavy oil on the safe operation of the pipeline. At least one end of the autoclave cavity 26 is an openable sealing setting. The control unit is used to control the heavy oil temperature and gas pressure in the autoclave. The data acquisition processing unit 30 is used to collect the viscosity of the heavy oil in the autoclave under a certain temperature and pressure environment, the reciprocating motion time data of the metal ball, and the adhesion amount of the heavy oil on the wall surface and the metal ball surface, and calculate the minimum value of the safe transportation temperature of the heavy oil. The specific collection method of the adhesion amount of the heavy oil on the wall surface and the metal ball surface can be: after the autoclave is depressurized and the oil-water mixture is discharged, the chamber of the autoclave is opened and the heavy oil in the corresponding part is taken out for weighing.

[0038] In order to study and evaluate the adhesion behavior of heavy oil with high asphaltene and colloid content on the inner wall of the pipeline during transportation, evaluate the wall adhesion temperature of the heavy oil and the influence on the safe operation of the pipeline, the present invention simulates the shear and flow in the pipeline through the swinging motion of the autoclave and the reciprocating motion of the metal ball in the autoclave, simulates the environment of the fluid in the pipeline through water bath temperature control and pressure regulation, makes the heavy oil flow in the autoclave cavity of the evaluation device, and online measures the reciprocating motion time of the metal ball and the viscosity of the pipe wall adhesion, so as to jointly evaluate the adhesion state of the heavy oil to be tested through these two indicators, and evaluates the adhesion rate of the heavy oil on the wall and the influence on the pipeline operation by measuring the quality of the adhesion. Further, by calculating the minimum value of the safe transportation temperature of the heavy oil, the safe transportation temperature in the actual pipeline can be effectively predicted.

[0039] Further Figure 1As shown, the material of the autoclave cavity of the present invention can be stainless steel, carbon steel, fiberglass or other materials, preferably stainless steel. The metal ball can use a steel ball, an iron ball, a copper ball or other metal balls, preferably a steel ball. The pressure that the autoclave can withstand is preferably 0.1 to 10 MPa, and the operating temperature is -10°C to 80°C. The inner diameter of the autoclave cavity 26 is preferably 8 cm, and the effective length of the cavity is preferably 30 cm. Furthermore, in addition to the cavity 26 and the metal ball, the autoclave may include accessories such as fixing bolts 4, a left end cover 5, nuts 6, partitions 9, a right end cover 16, and a support seat 24. The left end cover 5 and the right end cover 16 are connected to the autoclave cavity 26 through four fixing bolts 4 and nuts 6 respectively to achieve sealing of the autoclave. The partition 9 is arranged in the autoclave cavity 26 to limit the movement range of the metal ball 10 and prevent the temperature sensor 29 and the pressure sensor 7 in the cavity 26 from colliding with the metal ball 10. The metal ball 10 can perform reciprocating swinging motion in the autoclave along with the movement of the autoclave, and is used to shear the heavy oil fluid in the autoclave and reflect the influence of the heavy oil on the safe operation of the pipeline. The autoclave support seat 24 is used to support the autoclave to perform swinging motion. Preferably but not restrictively, a metal ball displacement sensor 23 is provided on the outer wall of the stainless steel cavity 26 of the autoclave, and an online viscometer 8 is provided on the inner wall of the cavity 26. The displacement sensor 23 is used to collect the reciprocating motion time data of the metal ball, and the online viscometer 8 is used to detect the viscosity data of the heavy oil to be tested in the autoclave in real time.

[0040] Further Figure 1 As shown, the autoclave of the present invention drives the rotating wheel 19 through the motor 20, thereby driving the double-link mechanism to achieve periodic swinging motion. Specifically, the mechanism for achieving the swinging of the autoclave includes an autoclave connecting rod 17, a connecting rod 18, a rotating wheel 19 and a motor 20. The autoclave connecting rod 17 is fixedly connected to the right end cover 16 of the autoclave. The autoclave connecting rod 17 and the connecting rod 18 are movably hinged. Preferably, but not restrictively, the autoclave connecting rod 1) can be provided with a plurality of connection positions ( Figure 1 There are three connection positions in the middle), and the swing amplitude of the autoclave can be adjusted by adjusting the connection position according to the test needs. The connecting rod 18 and the rotating wheel 19 are eccentrically connected. Through the action of the above-mentioned swing mechanism, the swing amplitude of the autoclave can be controlled to ±30°~±90°, and the swing cycle can be controlled to 0~60 times / min. .

[0041] Further Figure 1As shown, the control unit may include a temperature control subunit and a pressure control subunit. The temperature control subunit may control the temperature through a temperature-controlled water bath 21 and a water jacket 25 wrapped around the outer wall of the autoclave, and monitor the temperature of the heavy oil in the autoclave through a temperature sensor 29. Specifically, the temperature control subunit includes a temperature-controlled water bath 21, a water bath water inlet pipeline 15, a water bath water outlet pipeline 28, a water jacket 25, a water jacket water outlet 14, and a water jacket water inlet 27. The cold water or hot water in the temperature-controlled water bath 21 enters the water jacket 25 from the water bath water outlet pipeline 28 through the water jacket water inlet 27, and then flows in the water jacket 25 to exchange heat with the fluid in the autoclave, and finally returns to the temperature-controlled water bath 21 through the water jacket water outlet 14 and the water bath water inlet pipeline 15. The pressure control subunit may provide the test gas to the autoclave through the gas tank 1 and the valve and pressurize it to the required pressure, and a gas flowmeter 2 is provided on the gas supply pipeline. Specifically, the pressure control subunit includes a gas tank 1, an air inlet valve 3 and a vent valve 11. The gas tank 1 is used to supply test gas, and the test gas in the gas tank 1 is methane gas, ethane gas, carbon dioxide gas, natural gas or a mixed gas. The gas enters the autoclave cavity 26 from the gas tank 1 through the air inlet valve 3 to pressurize the space inside the autoclave, and the vent valve 11 is used to discharge gas and emergency vent.

[0042] Further Figure 1 As shown, the data acquisition processing unit 30 records the collected autoclave temperature, pressure data, intake air flow data, heavy oil viscosity, and metal ball reciprocating motion time data, and calculates the minimum temperature for safe transportation of heavy oil through the collected autoclave swing motion frequency and heavy oil colloid asphaltene total content data. Specifically, the autoclave temperature, pressure data, and intake air flow data are measured by the temperature sensor 29, the pressure sensor 7, and the gas flow meter 2, respectively. The heavy oil viscosity and the metal ball reciprocating motion time data can be measured by the online viscometer 8 and the displacement sensor 23, respectively. The online viscometer 8 can measure the viscosity of the fluid in the autoclave in real time through the time of piston movement, and the displacement sensor 23 can collect the time of one reciprocating motion of the metal ball. The viscosity state of the heavy oil to be tested is measured and evaluated by the online viscosity data and the metal ball reciprocating motion time data, which can corroborate the evaluation results and make the data more accurate. In order to more accurately quantify the influence of heavy oil viscosity on actual pipeline transportation, the present invention can calculate the minimum temperature for safe transportation of heavy oil through the collected data of high pressure autoclave swinging motion frequency and total content of heavy oil colloid asphaltene, and compare the calculated value with the temperature value of the mass increase of heavy oil wall adhesion, so it can be judged that the above calculation method of the present invention is closer to the measured value, and can be used to predict the influence of heavy oil transportation in actual pipeline.

[0043] Further Figure 1As shown, the evaluation device of the present invention may further include a liquid discharge unit, which includes a liquid discharge valve 22 for discharging the oil-water mixture through a liquid discharge pipeline before the heavy oil is weighed.

[0044] like Figure 1 As shown, the present invention also provides a method for evaluating the wall adhesion quality of heavy oil, the heavy oil being heavy oil with high asphaltene and colloid content, the method may include the following steps:

[0045] Step S101, start the temperature-controlled water bath 21 and increase the temperature. Before the evaluation operation is performed, the temperature of the temperature-controlled water bath 21 is first adjusted to the set temperature, and the water bath circulation is started. Hot water enters the water jacket 25 from the water bath outlet pipe 28 through the water jacket water inlet 27, and then returns to the constant temperature water bath through the water jacket outlet 14 and the water bath inlet pipe 15;

[0046] Step S102, cleaning the autoclave. First, the left end cover 5 is opened, and the metal ball 10, the autoclave cavity 26 and the end cover are rinsed with deionized water to remove surface impurities, and then the above components are further cleaned with petroleum ether to remove oil stains.

[0047] Step S103, after the cleaning step is completed, pour the heavy oil to be tested. Adjust the angle of the autoclave to pour the water-containing heavy oil with high asphaltene and colloid content into the autoclave cavity 26.

[0048] Step S104, exhaust the residual air in the autoclave cavity 26. Install the left end cover 5 and seal it with the fixing bolts 4 and nuts 6, open the vacuum valve 12 and the vacuum pump 13, and exhaust the residual gas in the autoclave.

[0049] Step S105, start the autoclave swing mechanism and the data acquisition processing unit 30. While increasing the pressure, turn on the motor 20 to make the autoclave swing periodically and set the swing frequency. The metal ball 10 in the autoclave reciprocates with the operation of the autoclave. Turn on the online viscometer 8 and the data acquisition processing unit 30 to collect the pressure, temperature, intake air flow, displacement of the metal ball 10 and online viscosity in the autoclave in real time and display them on the computer 31.

[0050] Step S106, pressurizing the autoclave. Open the gas tank 1, inject the test gas into the autoclave cavity 26, so that the gas gradually dissolves in the liquid phase and realizes a high pressure environment in the autoclave. Meanwhile, during the test, the pressure in the autoclave is maintained constant by controlling the opening and closing of the air inlet valve 3.

[0051] Step S107, system cooling. When the pressure reaches the required test pressure, the temperature of the heavy oil fluid to be tested is gradually reduced to the test temperature at a set rate through the temperature-controlled water bath 21.

[0052] Step S108, after the temperature is constant, the autoclave moves stably at a fixed swing frequency for 15 minutes. At this time, the viscosity of the fluid and the time it takes for the metal ball 10 to reciprocate once are measured by the online viscometer 8.

[0053] Step S109, measuring the adhesion amount of heavy oil on the wall surface. When the autoclave operation is completed, the pressure in the autoclave is released, and the oil-water mixture is discharged through the drain valve 22, and then the left end cover 5 is opened to scrape and weigh the heavy oil adhering to the inner wall surface and the metal ball to obtain the adhesion amount.

[0054] Step S110, lower the experimental temperature by 2°C, repeat steps 102 to 109, continue to evaluate the wall adhesion quality of heavy oil, determine the minimum value (i.e., test value) of the safe transportation temperature of heavy oil by the temperature at which the adhesion quality suddenly changes (i.e., increases sharply), evaluate the influence of heavy oil on the safe operation of pipeline in multiple dimensions by the metal ball reciprocating motion time data, viscosity real-time data and adhesion amount weighed in step S109 in step S108, continue a set of tests after the wall adhesion quality increases, and then end the experiment. Further, calculate the minimum temperature (i.e., calculated value) for safe transportation of heavy oil by the collected autoclave swing motion frequency and the total content data of heavy oil colloid asphaltene, compare the calculated value with the temperature value (i.e., test value) at which the quality of heavy oil adhesion to the wall increases sharply, judge the closeness between the above-mentioned calculation method of the present invention and the test value, and thus use the calculation method of the present invention to predict the influence of heavy oil transportation in actual pipelines.

[0055] Specifically, the calculation of the minimum temperature for safe transportation of heavy oil according to the present invention can be carried out in the following manner:

[0056]

[0057] Among them, T S The lowest temperature for safe transportation of heavy oil; T G is the condensation point of the heavy oil to be tested; f is the swing frequency of the autoclave, C AR It is the total content of colloid asphaltene in heavy oil.

[0058] The evaluation method of the invention can measure the viscosity of water-containing heavy oil and its adhesion quality on the pipeline wall under different conditions, determine the minimum temperature for safe transportation of water-containing heavy oil, and is beneficial to the economical and efficient transportation of water-containing heavy oil.

[0059] Example 1

[0060] In this embodiment, water-containing heavy oil with high asphaltene and colloid content is used to conduct adhesion quality evaluation test through the aforementioned evaluation device. The heavy oil used in this embodiment has an asphaltene content of 14.50wt%, a colloid content of 15.96wt%, a total amount of colloid and asphaltene of 30.46wt%, and a freezing point of 42°C.

[0061] The specific operation steps of this embodiment are as follows:

[0062] (1) Turn on the temperature-controlled water bath and raise the temperature. Before the evaluation operation is performed, first adjust the temperature of the temperature-controlled water bath to 50°C, turn on the water bath circulation, and let the hot water flow from the water bath outlet pipe through the water jacket inlet into the water jacket, and then return to the constant temperature water bath through the water jacket outlet and the water bath inlet pipe.

[0063] (2) Clean the autoclave. First, open the left end cover of the autoclave, rinse the metal ball, autoclave cavity and end cover with deionized water to remove surface impurities, and then use petroleum ether to further clean the above components to remove oil stains.

[0064] (3) After the cleaning step, pour the heavy oil liquid to be tested. Adjust the angle of the autoclave and pour the water-containing heavy oil with high asphaltene and colloid content into the autoclave cavity. The water content of the heavy oil is 80% and the total volume is 500 mL.

[0065] (4) Expel the residual air in the autoclave cavity. Install the left end cover and seal it with the fixing bolts and nuts, open the vacuum valve and vacuum pump, and exhaust the residual gas in the autoclave.

[0066] (5) Turn on the autoclave swing mechanism and data acquisition and processing unit. While increasing the pressure, turn on the motor to make the autoclave swing periodically at a frequency of 20 times / min. The metal ball in the autoclave moves back and forth as the autoclave runs. Turn on the online viscometer and data acquisition and processing unit to collect the pressure, temperature, air intake flow, metal ball displacement and online viscosity in the autoclave in real time and display them on the computer.

[0067] (6) Pressurize the autoclave. Open the gas tank and inject carbon dioxide into the autoclave cavity to make the gas gradually dissolve in the liquid phase and achieve a high-pressure environment in the autoclave. At the same time, during the test, the pressure in the autoclave is maintained constant by controlling the opening and closing of the air inlet valve.

[0068] (7) Cooling the system. When the pressure reaches 0.8 MPa, the fluid temperature is gradually reduced to 45 °C at a rate of 0.5 °C / min using a temperature-controlled water bath.

[0069] (8) After the temperature is constant, the autoclave is allowed to move stably at a fixed swing frequency for 15 min. At this time, the fluid viscosity and the time it takes for the metal ball to reciprocate once are measured using an online viscometer.

[0070] (9) Determine the amount of heavy oil adhering to the wall. When the autoclave is finished, release the pressure inside the autoclave and discharge the oil-water mixture through the drain valve. Then open the left end cover and scrape and weigh the heavy oil adhering to the inner wall and the metal ball to obtain the adhesion amount.

[0071] (10) The experimental temperature is lowered by 2°C, and steps 2 to 9 are repeated to continue evaluating the wall adhesion quality of the heavy oil. The minimum value of the safe transportation temperature of the heavy oil is determined by the temperature at which the adhesion quality suddenly changes. When the wall adhesion quality increases, another set of experiments is continued, and then the experiment is terminated. Referring to Table 1, the minimum temperature for safe transportation of the heavy oil (i.e., the calculated value of 37.7°C) is calculated by the collected autoclave swing motion frequency (i.e., 20 times / min) and the total content of colloid and asphaltene in the heavy oil (i.e., colloid content of 15.96wt% and asphaltene content of 14.50wt%). The calculated value is compared with the temperature value at which the quality of the heavy oil wall adhesion increases (i.e., the test value of 39°C). The deviation is -1.3°C. It is judged that the above-mentioned calculation method of the present invention is close to the test value, and the calculation method of the present invention can be used to predict the impact of heavy oil transportation in actual pipelines.

[0072] Specifically, the above test results show that as the experimental temperature gradually decreases, the adhesion quality of heavy oil on the wall of the autoclave gradually increases, the viscometer reading gradually rises, the movement of the metal ball is hindered, and the reciprocating time is prolonged. When the test temperature decreases from 45°C to 37°C, the viscosity gradually increases from 540mpa·s to 906mpa·s, indicating that the viscosity of water-containing heavy oil is sensitive to temperature and gradually increases with decreasing temperature. High viscosity will increase the adhesion quality of heavy oil on the pipeline wall. Figure 2 As shown in the figure, when the test temperature is 45℃, the adhesion mass is 1.28g, and then the adhesion mass gradually increases as the test temperature decreases. When the test temperature is about to reach 41℃, the adhesion mass increases to 1.80g, and when the test temperature is further reduced to 39℃, the adhesion mass increases sharply to 2.76g. At this time, there is a serious safety hazard to the safe operation of the pipeline. Therefore, 39℃ is used as the minimum safe transportation temperature of the water-containing heavy oil under this condition (i.e., the test value). Low-temperature operation will reduce the energy consumption of the heating furnace, reduce the transportation cost of heavy oil while ensuring safety, and achieve the effect of energy saving and consumption reduction.

[0073] Table 1 Comparison of calculated and experimental minimum temperatures for safe transportation of heavy oil with high asphaltene and colloid content

[0074]

[0075] Example 2

[0076] The difference between this embodiment and embodiment 1 is that the total content of colloid and asphaltene in the crude oil used is different. The asphaltene content of the heavy oil used in this embodiment is 12.25wt%, the colloid content is 11.55wt%, the total amount of colloid and asphaltene is 23.80wt%, and the pour point is 19°C.

[0077] The evaluation test was conducted under the same conditions as in Example 1. Since the content of colloidal asphaltene in this example is lower than that in Example 1, the water bath was initially heated to 25°C according to the difference in the freezing point of the crude oil, and then the temperature was gradually lowered for the evaluation test. The adhesion mass of the water-containing heavy oil at 20°C, 18°C, 16°C, 14°C and 12°C was 1.54g, 1.68g, 2.12g, 3.4g and 3.6g, respectively. It can be seen that the adhesion mass of the water-containing heavy oil on the wall increases after 16°C, so the minimum temperature for safe transportation under this condition is determined to be 16°C. The calculated value of the minimum temperature for safe transportation calculated by the calculation method of the aforementioned Example 1 is 16.1°C, with a deviation of only 0.1°C (see Table 1 for the test and calculation results).

[0078] Example 3

[0079] The difference between this embodiment and embodiment 1 is that the total amount of colloid and asphaltene content of the crude oil used is different. The asphaltene content of the heavy oil used in this embodiment is 6.33wt%, the colloid content is 9.12wt%, the total amount of colloid and asphaltene is 15.45wt%, and the pour point is 13°C. The swing frequency of the autoclave is set to 30 times / min. The evaluation device of the present invention is used for experimental verification. The experimental operation process is consistent with that of embodiment 1. The calculation results and the experimental results are shown in Table 1.

[0080] Example 4

[0081] The difference between this embodiment and embodiment 1 is that the total amount of colloid and asphaltene content of the crude oil used is different. The asphaltene content of the heavy oil used in this embodiment is 12.01wt%, the colloid content is 16.97wt%, the total amount of colloid and asphaltene is 28.98wt%, and the pour point is 35°C. The swing frequency of the autoclave is set to 40 times / min. The evaluation device of the present invention is used for experimental verification. The experimental operation process is consistent with that of embodiment 1. The calculation results and the test results are shown in Table 1.

[0082] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. Any simple modifications, equivalent changes and modifications made to the above exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A device for evaluating the quality of heavy oil wall adhesion, characterized in that: The heavy oil is a heavy oil with high asphaltene and colloid content. The device comprises: The autoclave is arranged horizontally and used to load the heavy oil to be tested. During the test, the autoclave performs periodic swinging motion, and a freely movable metal ball is arranged in the autoclave; at least one end of the chamber of the autoclave is an openable sealing arrangement; A control unit, which is used to control the heavy oil temperature and gas pressure in the autoclave; The data acquisition and processing unit is used to collect the viscosity of the heavy oil in the autoclave under a certain temperature and pressure environment, the reciprocating motion time data of the metal ball, and the adhesion amount of the heavy oil on the wall and the surface of the metal ball, and calculate the minimum value of the safe transportation temperature of the heavy oil.

2. The device for evaluating the wall adhesion quality of heavy oil according to claim 1, characterized in that: The metal ball performs reciprocating swinging motion in the autoclave along with the swinging motion of the autoclave, so as to perform shear disturbance on the heavy oil fluid in the autoclave. The reciprocating motion time data of the metal ball and the real-time measured heavy oil viscosity data are used to evaluate the influence of the heavy oil on the safe operation of the pipeline.

3. The device for evaluating the wall adhesion quality of heavy oil according to claim 1, characterized in that: The amount of heavy oil adhering to the wall and the metal ball surface is collected by: after the autoclave is depressurized and the oil-water mixture is discharged, the chamber of the autoclave is opened and the heavy oil in the corresponding part is taken out for weighing.

4. The device for evaluating the wall adhesion quality of heavy oil according to claim 1, characterized in that: The autoclave is a stainless steel chamber with end covers at both ends for sealing; a metal ball displacement sensor is provided on the outer wall of the stainless steel chamber, and an online viscometer is provided on the inner wall of the stainless steel chamber.

5. The device for evaluating the wall adhesion quality of heavy oil according to claim 1, characterized in that: The autoclave drives a rotating wheel through an electric motor, thereby driving a double-link mechanism to achieve periodic swinging motion; a support seat for supporting the swinging is provided at the bottom of the autoclave.

6. The device for evaluating the wall adhesion quality of heavy oil according to claim 5, characterized in that: The double-link mechanism is provided with a plurality of connection positions for adjusting the swing amplitude of the autoclave according to test requirements.

7. The device for evaluating the wall adhesion quality of heavy oil according to claim 1, characterized in that: The control unit comprises: A temperature control subunit, which controls the temperature through a temperature-controlled water bath and a water jacket wrapped around the outer wall of the autoclave, and monitors the temperature of the heavy oil in the autoclave through a temperature sensor; The pressure control subunit supplies test gas to the autoclave through a gas tank and a valve and pressurizes it to the required pressure. A gas flow meter is provided on the gas supply pipeline.

8. The device for evaluating the wall adhesion quality of heavy oil according to claim 1, characterized in that: The data acquisition and processing unit records the collected autoclave temperature, pressure data, intake air flow data, the heavy oil viscosity, and the reciprocating motion time data of the metal ball, and calculates the minimum temperature for safe transportation of the heavy oil through the collected autoclave swing motion frequency and the total content of heavy oil colloid asphaltene data.

9. The device for evaluating the wall adhesion quality of heavy oil according to claim 1, characterized in that: The evaluation device also includes: The liquid discharge unit comprises a liquid discharge valve, which is used to discharge the oil-water mixture through a liquid discharge pipeline before the heavy oil is weighed.

10. The device for evaluating the wall adhesion quality of heavy oil according to claim 6, characterized in that: The swing amplitude of the autoclave is ±30° to ±90°.

11. The device for evaluating the wall adhesion quality of heavy oil according to claim 7, characterized in that: The test gas in the gas tank is methane gas, ethane gas, carbon dioxide gas, natural gas or a mixed gas.

12. A method for evaluating the wall adhesion quality of heavy oil, characterized in that: The heavy oil is a heavy oil with high asphaltene and colloid content. The method comprises the following steps: A. Turn on the temperature-controlled water bath and adjust it to the set temperature; load the heavy oil to be tested into the autoclave and extract the residual gas in the autoclave; B. driving the autoclave to perform reciprocating swinging motion while increasing pressure and recording the swinging frequency; the reciprocating motion of the metal ball during the periodic swinging motion of the autoclave exerts shear disturbance on the heavy oil fluid in the autoclave; C. Gradually lowering the set temperature to the test temperature through the constant temperature water bath; D. Collect and record the real-time data of pressure, temperature, air flow rate, metal ball reciprocating motion time and viscosity in the autoclave; E. Stop the swinging motion of the autoclave and perform pressure relief treatment, drain the oil-water mixture in the autoclave and scrape and weigh the heavy oil adhering to the inner wall of the autoclave and the metal ball to obtain the adhesion amount; evaluate the influence of the heavy oil on the safe operation of the pipeline through the reciprocating motion time data of the metal ball and the real-time viscosity data; calculate the minimum temperature for safe transportation of the heavy oil through the swinging frequency of the autoclave and the total content of colloid and asphaltene in the heavy oil.

13. The method for evaluating the wall adhesion quality of heavy oil according to claim 12, characterized in that: The minimum temperature for safe transportation of heavy oil is calculated as follows: Among them, T S The lowest temperature for safe transportation of heavy oil; T G is the condensation point of the heavy oil to be tested; f is the swing frequency of the autoclave, C AR It is the total content of colloid asphaltene in heavy oil.

14. The method for evaluating the wall adhesion quality of heavy oil according to claim 12, characterized in that: A cleaning step is also included between step A and step B.

15. The method for evaluating the wall adhesion quality of heavy oil according to claim 14, characterized in that: The cleaning step specifically comprises: washing the metal ball, the autoclave chamber and the end cover with deionized water to remove surface impurities, and then further washing with petroleum ether to remove oil stains.

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