Simulated oil preparation method for evaluating influence of stability of super-heavy oil emulsion

Abstract

The invention relates to the technical field of crude oil stability evaluation, in particular to a simulated oil preparation method for evaluating the influence of the stability of a super-heavy oil emulsion, which comprises the following steps: firstly, distilling crude oil at normal pressure to obtain residual oil; dissolving the residual oil with n-hexane, standing for layering, filtering and drying to obtain asphaltene; and concentrating the n-hexane filtrate, adding a benzene-acetone mixed solvent, dewaxing and carrying out suction filtration under a low-temperature condition, dissolving wax with hot petroleum ether, evaporating to remove the wax, and drying under a vacuum condition, thereby obtaining the product. Concentrating and drying the dewaxed filtrate to obtain coarse colloid; the method comprises the following steps of: quantitatively blending asphaltene, colloid and wax according to a preset proportion by taking a compound matrix consisting of methylbenzene and non-polar aviation kerosene in a mass ratio of 1: 1 as a carrier to construct a simulated oil system; then, the simulated oil and deionized water are mixed according to the oil-water ratio of 7: 3 and subjected to 10000 r / min high-speed shearing emulsification to obtain the super-heavy oil simulated emulsion, and the result shows that the system can accurately evaluate the stability of the high-content asphaltene and colloid crude oil emulsion.

Description

Technical Field

[0001] This invention relates to the field of crude oil stability assessment technology, specifically to a method for preparing simulated oil for evaluating the impact of extra-heavy oil emulsion stability. Background Technology

[0002] With societal development, global energy demand continues to increase, and oil is constantly being extracted and utilized, leading to a gradual decrease in the world's recoverable oil and gas resources. Light oil resources are becoming increasingly scarce, while heavy oil resources are very abundant globally. According to statistics, there are approximately 6 trillion barrels of heavy oil reserves globally, more than three times the total equivalent of ordinary crude oil and natural gas. my country has more than 70 heavy oil fields with proven reserves exceeding 4 billion tons. Therefore, the effective exploitation of heavy oil is of great strategic significance for ensuring the ever-increasing energy demand. In oil-water systems, the formation of stable oil-water emulsions is crucial for reducing the viscosity of heavy oil, improving its fluidity, and enhancing surface processing efficiency. However, the high viscosity and complex composition of heavy oil pose significant technical challenges in its extraction, transportation, and processing, particularly in oil-water emulsification, where it performs significantly worse than light oils. This is because heavy oil contains a high content of heavy components (asphaltene, gums, and waxes, etc.). The molecular structure and interfacial behavior of these components result in an interfacial film with high viscosity and cohesiveness at the oil-water interface, making it difficult to effectively disperse the aqueous phase into uniform and stable droplets under conventional shear conditions. Consequently, heavy oil and water are difficult to emulsify or the emulsion is unstable. Therefore, developing a controllable and repeatable quantitative evaluation system to systematically study the effects of different crude oil components on the stability of heavy oil emulsions is of great significance for optimizing oil-water separation technology, reducing energy consumption, reducing demulsifier usage, improving oil recovery rate, and enhancing crude oil quality. Currently, experts and scholars at home and abroad have proposed the following methods for evaluating the stability of heavy oil emulsions.

[0003] Bottle test method: This method involves placing the crude oil emulsion into an experimental container, stirring it thoroughly, and then allowing it to stand in a constant temperature environment. The amount of water deposited at the bottom of the container is recorded at regular intervals. The sedimentation dehydration rate is obtained by calculating the ratio of the amount of deposited water to the total water content of the emulsion, thereby evaluating the stability of the emulsion. However, this method relies on the operator's experience, is highly subjective, has poor repeatability, and makes it difficult to accurately compare results from different experimenters or laboratories. In addition, the bottle test method cannot quantify the microscopic stability of the emulsion, nor can it reveal the key components affecting stability and their mechanisms of action.

[0004] Interfacial property measurement: The diffusion modulus, elastic modulus, viscous modulus, and interfacial tension of the oil-water interfacial film are measured using a rotating drop interfacial tensiometer to assess the strength of the interfacial film. However, this measurement method is usually completed in a short time (a few minutes) and cannot reflect the stability evolution of heavy oil under actual working conditions. In addition, the interface of heavy oil emulsion is formed by components such as asphaltenes, gums, and waxes, with complex structure and multi-layered characteristics. Changes in interfacial tension and modulus may originate from the action mechanisms of multiple components simultaneously. The rotating drop measurement method can only reflect the equilibrium characteristics of the interface and is difficult to capture the synergistic and competitive action mechanisms of key components in heavy oil.

[0005] Microscopic observation and image analysis: This method observes the microscopic morphology of emulsions using an electron microscope and calculates the droplet size of the emulsion using microscopic analysis software. The stability of the emulsion is assessed by judging the uniformity of droplet distribution and the size of the droplets. However, heavy oil emulsions are usually non-homogeneous, and a single droplet sample is difficult to represent the properties of the entire emulsion. In addition, the microscope cannot identify the structure of solid particles and components such as asphaltene and gum at the droplet interface, and cannot accurately determine the dominant factors affecting the droplet properties.

[0006] A review of existing methods for evaluating the stability of extra-heavy oil emulsions reveals that most current methods struggle to achieve controllable and repeatable quantitative characterization. Furthermore, to accurately assess the impact of a single or multiple components (such as asphaltenes, gums, and waxes) on the stability of heavy oil emulsions, these components must be precisely separated from the crude oil and reformulated into simulated oil emulsions before stability evaluation. However, due to the complex compatibility and poor water solubility of components such as asphaltenes, gums, and waxes, precise reconstitution in simulated oil emulsions is difficult. Simultaneously, traditional simulated oils often use white oil or simple alkanes, where asphaltenes easily precipitate in pure alkanes, failing to form a stable colloidal system and thus unable to simulate the complex interfacial behavior of asphaltenes in extra-heavy oils. This results in significant discrepancies between existing simulation evaluation results and actual oilfield conditions.

[0007] Therefore, this invention proposes using a mixture of toluene and non-polar aviation kerosene as a simulated oil base liquid. Toluene, as an aromatic solvent, can effectively dissolve and disperse asphaltenes, allowing them to be uniformly dispersed in the oil phase as monomers or nanoscale polymers. Non-polar aviation kerosene can effectively simulate the oil phase components in crude oil. By combining toluene and non-polar aviation kerosene, a mixed medium environment close to real crude oil can be constructed. At the same time, it provides a more stable and repeatable experimental system that allows for free blending of "single-component, two-component, and three-component" formulations. Combined with various heavy oil emulsion stability evaluation methods proposed by domestic and foreign scholars and the innovative simulated oil preparation method of this invention, this invention can provide a more reliable experimental platform for systematically studying the influence of different crude oil components on the stability of heavy oil emulsions, and provide key theoretical basis and data support for the emulsification control and efficient demulsification process of extra-heavy oil. Summary of the Invention

[0008] This invention addresses the difficulty in achieving controllable, repeatable, and quantitative comparisons in existing stability evaluations of extra-heavy oil emulsions. It proposes a simulated oil preparation method for evaluating the influence of crude oil components on the stability of extra-heavy oil emulsions. This method constructs a repeatable simulated oil-based liquid system using "toluene + non-polar aviation kerosene," where toluene is used to dissolve and disperse asphaltenes, and non-polar aviation kerosene is used to simulate the crude oil phase matrix. This provides a stable and reproducible mixing medium environment for the free mixing of single and multiple components (asphaltene, gums, waxes), and simulated emulsions are prepared under uniform emulsification conditions to achieve comparable evaluations of different component systems.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: S1. Crude oil pretreatment and residual oil collection: Transfer the crude oil sample to a pre-weighed distillation flask (avoiding entry into the side arm), weigh the sample, install a thermometer with its mercury bulb at the center of the neck and the bottom of its capillary tube flush with the highest point of the bottom of the side arm of the distillation flask, place the receiving cylinder below the condenser outlet, and insert the condenser into the cylinder at least 25 mm. Heat the distillation flask steadily until the sample boils, control the distillation rate within the predetermined range, and continue distilling until the temperature reaches 250°C. After the residual oil cools to room temperature, weigh the mass of the residual oil in the distillation flask.

[0010] S2. Asphalt separation and recovery: Weigh an appropriate amount of residual oil sample into a pre-weighed ground glass conical flask, add the specified amount of n-hexane according to Table 1 and dissolve it completely. Place the conical flask in an ultrasonic oscillator and vibrate for 40 minutes. Then, move it to the dark to cool and stand for 45 minutes to 1 hour. After the layers separate, filter it. Transfer all the residue in the flask to a glass funnel containing quantitative filter paper and filter it using the gentle slurry method (without stirring). Place the filter paper containing insoluble matter in a fume hood and dry it for 3 minutes. Then, let it air dry naturally in the dark and collect the asphalt particles.

[0011] Table 1. Specified usage amounts of n-hexane and residual oil samples S3. Wax Separation and Recovery: Collect the hexane filtrate, concentrate it, and then add a benzene-acetone mixture. Transfer the solution to a sample tube in a wax content analyzer. Wash the ground glass conical flask three times with a dewaxing agent. Pour the washing solution into the sample tube. Adjust the temperature of the wax content analyzer to -22℃±0.5℃. Install the sample tube and stir to cool. After the system reaches -20℃, continue stirring for 30 minutes. Simultaneously, pre-cool the dewaxing solvent, place quantitative filter paper at the bottom of a sintered glass funnel, and quickly pour the mixture from the sample tube into the funnel. Turn on the vacuum pump for suction filtration. After suction filtration is complete... The sample tube was washed twice (10 ml each time) with a benzene-acetone mixture pre-cooled to -20℃. The washing solution was poured into a sintered glass funnel, stirred, and then filtered. After filtration, the wax in the sintered glass funnel was dissolved with hot petroleum ether at 40℃~45℃ and transferred to a pre-weighed ground glass conical flask. The petroleum ether was evaporated to near dryness at 90℃~95℃ in a fume hood. The sample tube was then dried in a vacuum drying oven at 105℃±5℃ and a negative pressure of 53.3kPa~66.7kPa for 60 min. After cooling for 40 min, the sample tube was weighed to obtain the mass of the wax.

[0012] S4. Separation and recovery of colloids: Collect the benzene-acetone filtrate from step S3 into a beaker, concentrate and air dry it in a fume hood, and let it stand in the dark for 5-6 hours to obtain crude colloids.

[0013] S5. Construction and component remixing of simulated oil-based liquid: Weigh the asphaltene collected in step S2 and dissolve it in toluene. After the asphaltene is completely dissolved, add non-polar aviation kerosene to prepare asphaltene simulated oil. Weigh the wax and gum collected in steps S2 and S3 respectively and dissolve them in non-polar aviation kerosene to prepare the corresponding wax simulated oil and gum simulated oil. Then, remix the single component or multiple components according to the preset ratio to construct a simulated oil system for stability evaluation.

[0014] S6. Preparation of simulated oil emulsion: The simulated oil prepared in step S4 is mixed with deionized water at a fixed oil-water ratio, and then homogenized and emulsified at high speed using a high-speed homogenizer under fixed rotation speed and time conditions to obtain a heavy oil simulated emulsion.

[0015] Based on the above methods, a blank reference emulsion system can be further prepared: a simulated oil is made by using only toluene and non-polar aviation kerosene, and an emulsion is prepared under the same emulsification conditions. This emulsion is used as a control that does not have emulsification ability, so as to highlight the contribution of heavy components to interfacial film formation and stability.

[0016] According to a preferred embodiment of the present invention, in step S1, the condensate distillation rate is maintained at 2.0 mL / min to 2.5 mL / min, and heating is stopped when the distillation temperature reaches 250°C.

[0017] According to the preferred embodiment of this experiment, in step S2, n-hexane is used to dissolve the residual oil.

[0018] According to a preferred embodiment of the present invention, in step S3, the filtrate filtered with n-hexane is concentrated to 10 ml, the amount of benzene-acetone mixed solution added is 60 ml, the ambient temperature for dewaxing and filtration is -20°C, and the amount of dewaxing agent used is 10 ml.

[0019] According to a preferred embodiment of the present invention, in step S5, the mass ratio of toluene to non-polar aviation kerosene in the asphaltene simulated oil is 1:1.

[0020] According to a preferred embodiment of the present invention, in step S5, a stable solvated shell is formed by pre-dissolving asphaltene with toluene, and then non-polar aviation kerosene is introduced to simulate the dilution environment of light components on heavy components in heavy oil, thereby reconstructing a colloidal stability structure similar to that of real crude oil at the microscopic level.

[0021] According to a preferred embodiment of the present invention, in step S6, the oil-water mixing ratio of the simulated oil and deionized water is 7:3.

[0022] According to a preferred embodiment of the present invention, in step S6, the rotation speed of the high-speed homogenizer is 10000 r / min, and the stirring time is 2 min.

[0023] Technical features and advantages of the present invention: This invention provides a method for efficiently separating key components of crude oil and preparing simulated oil emulsions. This method, while ensuring high separation efficiency and low component loss, can achieve efficient quantitative separation and re-preparation of three key components: asphaltenes, resins, and waxes, thereby constructing a repeatable and comparable simulated oil system. Compared to directly using crude oil samples for experimental design, this invention reduces the interference of batch differences and complex component coupling on the results by constructing a controllable reference oil phase with "no self-emulsification ability," and forms a clear control under the same emulsification conditions: the blank reference system is difficult to form a stable interfacial film and is prone to stratification, while the introduction of heavy components can significantly improve the interfacial viscoelastic properties and dispersion state, thereby improving the stability of the emulsion. Furthermore, this invention supports the separation and re-preparation of single or multiple components according to preset ratios. The free mixing allows for systematic observation of the independent contributions and synergistic / competitive effects of asphaltenes, gums, and waxes on emulsion stability. In terms of stability evaluation, this invention combines emulsification under identical operating conditions with multi-dimensional quantitative characterization (such as water separation rate, interfacial viscoelasticity, microparticle size / morphology) to establish a quantifiable and reproducible stability comparison and evaluation platform. Notably, a toluene-nonpolar aviation kerosene composite base fluid system is employed: toluene provides the ability to dissolve and disperse asphaltenes, while nonpolar aviation kerosene provides a nonpolar matrix environment close to that of real crude oil, balancing solubility and matrix similarity. This makes the constructed simulation system more closely resemble the oil phase conditions of high-asphaltene heavy oil, thus more effectively characterizing the emulsification behavior of extra-heavy oil in actual production processes and providing a scientific basis for the stable regulation and efficient extraction of extra-heavy oil emulsions. Attached Figure Description

[0024] Purpose of the accompanying drawings: In order to more clearly illustrate the embodiments of the invention and the technical solutions, the accompanying drawings used in the embodiments will be briefly labeled and introduced below.

[0025] Figure 1 For wax content determination instrument; Figure 2 Images showing the separation of bituminous, resinous, and waxy substances; In the figure: (a) is a sample of asphalt separation; (b) is a sample of gum separation; (c) is a sample of wax separation. Figure 3 Image of a simulated emulsion sample of heavy oil; In the figures: (a) is a sample of the heavy oil simulated emulsion from Example 1; (b) is a sample of the heavy oil simulated emulsion from Example 4; (c) is a diagram of the preparation of the heavy oil simulated emulsion from Example 5; and (d) is a sample of the heavy oil simulated emulsion from Example 6. Figure 4 The following are water separation rate test charts for each embodiment; In the figures: (a) is the water separation rate of the simulated heavy oil emulsion prepared in Example 1; (b) is the water separation rate of the simulated heavy oil emulsion prepared in Example 4; (c) is the water separation rate of the simulated heavy oil emulsion prepared in Example 5; (d) is the water separation rate of the simulated heavy oil emulsion prepared in Example 6. Figure 5 This is a graph showing the stability evaluation of the simulated heavy oil emulsion in Example 1. In the figure: (a) is the viscous modulus diagram; (b) is the elastic modulus diagram; (c) is the diffusion modulus diagram; (d) is the loss factor diagram. Figure 6 This is a graph showing the stability evaluation of the simulated heavy oil emulsion in Example 4; In the figure: (a) is the viscous modulus diagram; (b) is the elastic modulus diagram; (c) is the diffusion modulus diagram; (d) is the loss factor diagram; Figure 7 This is a graph showing the stability evaluation of the simulated heavy oil emulsion in Example 5. In the figure: (a) is the viscous modulus diagram; (b) is the elastic modulus diagram; (c) is the diffusion modulus diagram; (d) is the loss factor diagram; Figure 8 This is a graph showing the stability evaluation of the simulated heavy oil emulsion in Example 6. In the figure: (a) is the viscous modulus diagram; (b) is the elastic modulus diagram; (c) is the diffusion modulus diagram; (d) is the loss factor diagram;

[0026] Figure 9 Microscopic observation images of the heavy oil simulated emulsions in each embodiment; In the figure: (A) is a microscopic morphology diagram of the simulated heavy oil emulsion of Example 1; (B) is a microscopic morphology diagram of the simulated heavy oil emulsion of Example 4; (C) is a microscopic morphology diagram of the simulated heavy oil emulsion of Example 5; (D) is a microscopic morphology diagram of the simulated heavy oil emulsion of Example 6; (E) is a microscopic morphology diagram of the simulated heavy oil emulsion of Example 7. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the specification, not all embodiments. Other embodiments obtained by those skilled in the art based on one or more embodiments of the specification without creative effort should fall within the protection scope of the embodiments of this specification.

[0028] Example 1: Preparation of simulated asphalt-based heavy oil emulsions with concentrations of 2%, 4%, 6%, 8%, and 10%. Transfer approximately 100g of crude oil sample to a pre-weighed distillation flask, ensuring the sample does not flow into the side arm of the flask. Weigh the sample. Then, insert a thermometer with a sealing plug into the neck of the distillation flask containing the sample, ensuring the thermometer bulb is centered and the bottom of the thermometer capillary is level with the highest point of the bottom of the side arm. Place the receiving cylinder below the condenser outlet, allowing the condenser to extend at least 25mm into the cylinder. Heat the distillation flask steadily until the sample boils, maintaining a distillation rate of 2.0mL / min to 2.5mL / min. Continue distilling until the temperature reaches 250℃, then stop heating. After the residual oil cools to room temperature, weigh the residual oil in the distillation flask. 100g of residual oil will yield 55g after atmospheric distillation.

[0029] Add 5g of residual oil to a ground-glass conical flask, and add 30 times the amount of n-hexane (i.e., 150ml) according to Table 1 to obtain a mixed reagent of residual oil and n-hexane. Place the ground-glass conical flask containing the reagent in an ultrasonic oscillator and vibrate for 40min, then cool in the dark for 45min to 1h until it separates into layers. Subsequently, transfer all the reagent in the ground-glass conical flask to a glass funnel with quantitative filter paper, and filter by pouring (without stirring). Place the filter paper with insoluble matter in a fume hood for 3min to dry, then transfer it to the dark to air dry naturally, and collect asphaltene particles. Finally, after filtering 55g of residual oil through the filter paper, 13.3g of asphaltene particles are obtained.

[0030] Weigh out 0.4g, 0.8g, 1.2g, 1.6g, and 2.0g of asphaltene and dissolve it in toluene. After the asphaltene is dissolved, add non-polar aviation kerosene (the mass ratio of toluene to non-polar aviation kerosene is 1:1) to obtain asphaltene simulated oils with concentrations of 2%, 4%, 6%, 8%, and 10%. Mix the asphaltene simulated oils with deionized water at an oil-water ratio of 7:3 and stir at high speed for 2 minutes using a WIGGENS D-500 high-speed homogenizer at a speed of 10000 r / min to obtain asphaltene heavy oil simulated emulsions with concentrations of 2%, 4%, 6%, 8%, and 10%.

[0031] Example 2: Preparation of a 2% concentration wax-thick oil simulated emulsion Collect the filtrate obtained by filtration by the light purging method in step (3) of Example 1, concentrate it to 10 ml, add 60 ml of benzene-acetone mixed solution, transfer this mixture into the sample tube of the wax content analyzer, wash the ground glass conical flask three times with 10 ml of dewaxing solvent, and pour the washing solution into the sample tube.

[0032] Turn on the wax content analyzer and adjust the temperature to -22℃±0.5℃. Install the sample tube on the wax content analyzer and turn on the stirrer. After the temperature of the mixture reaches -20℃, continue stirring for 30 minutes. At the same time, put 20mL of dewaxing solvent into the solvent tube to cool, and cut the quantitative filter paper into appropriate sizes and place it at the bottom of the sand core funnel.

[0033] Remove the sample tube and pour the mixture into a sintered glass funnel for filtration. After filtration, wash the sample tube twice with a benzene-acetone mixture cooled to -20°C, 10 mL each time. Pour the washing solution into the sintered glass funnel and thoroughly mix the wax and dewaxing solvent in the funnel before filtration. After filtration, dissolve the wax on the sintered glass funnel in hot petroleum ether at 40°C–45°C into a pre-weighed ground glass conical flask. Then, move the ground glass conical flask to a fume hood and evaporate the petroleum ether to near dryness at 90°C–95°C using an evaporation recovery device.

[0034] Place the ground glass conical flask containing wax in a vacuum drying oven and dry it for 60 minutes at 105℃±5℃ and a negative pressure of 53.3kPa~66.7KPa. Remove the ground glass conical flask, place it in a desiccator to cool for 40 minutes, and then weigh it to obtain the mass of wax.

[0035] A certain amount of wax was dissolved in non-polar aviation kerosene to obtain a 2% wax-simulated oil. This simulated oil was mixed with deionized water at an oil-water ratio of 7:3 and stirred at high speed for 2 minutes at a speed of 10000 r / min using a WIGGENS D-500 high-speed homogenizer to obtain a 2% wax-concentrated heavy oil simulated emulsion.

[0036] Example 3: Preparation of a 2% concentration colloidal heavy oil simulated emulsion Collect the benzene-acetone filtrate from step (3) of Example 2 into a beaker, concentrate and air dry it in a fume hood, and finally let it stand in the dark for 5-6 hours to obtain 9.2g of crude gel.

[0037] A certain amount of gum was dissolved in non-polar aviation kerosene to obtain a simulated oil with a gum concentration of 2%. This simulated oil was then mixed with deionized water at a ratio of 7:3. The mixture was stirred at high speed for 2 minutes at a speed of 10,000 r / min using a WIGGENS D-500 high-speed homogenizer to prepare a 2% gum concentration viscous oil simulated emulsion.

[0038] Example 4: Preparation of a two-component asphaltene-colloidal heavy oil simulated emulsion Weigh 0.8g of the asphaltene from step (2) of Example 1, and weigh the gum from step (2) of Example 3 according to the ratio of asphaltene to gum of 4:1, 4:2, 4:3, 4:4, and 4:5. Dissolve the asphaltene with toluene, and after the asphaltene is dissolved, add non-polar aviation kerosene (the mass ratio of toluene to non-polar aviation kerosene is 1:1). Finally, add the gum. After the gum is dissolved, you can obtain two-component simulated oils with different ratios of asphaltene and gum.

[0039] The successfully prepared simulated oil was mixed with deionized water at an oil-water ratio of 7:3, and stirred at high speed for 2 minutes at a speed of 10000 r / min using a WIGGENS D-500 high-speed homogenizer to obtain a two-component simulated heavy oil emulsion of asphaltene and resin.

[0040] Example 5: Preparation of a two-component asphaltene-wax simulated heavy oil emulsion Weigh 0.8g of the asphaltene from step (2) of Example 1, and weigh the wax from step (4) of Example 2 according to the ratio of asphaltene to wax of 8:1, 8:2, 8:3, 8:4, and 8:5. Dissolve the asphaltene with toluene, and after the asphaltene is dissolved, add non-polar aviation kerosene (the mass ratio of toluene to non-polar aviation kerosene is 1:1). Finally, add the wax. After the wax is dissolved, you can obtain asphaltene-wax two-component simulated oils with different proportions.

[0041] The successfully prepared simulated oil was mixed with deionized water at an oil-water ratio of 7:3, and stirred at high speed for 2 minutes at a speed of 10000 r / min using a WIGGENS D-500 high-speed homogenizer to obtain a two-component simulated heavy oil emulsion of asphaltene-wax.

[0042] Example 6: Preparation of a three-component heavy oil simulated emulsion consisting of asphaltene, resin, and wax. Repeat step (1) of Example 4 to prepare a two-component simulated oil of asphaltene-resin with a ratio of 4:5. Weigh the wax from step (4) of Example 2 according to the ratios of asphaltene:resin:wax of 8:10:1, 8:10:2, 8:10:3, 8:10:4, and 8:10:5 respectively, and dissolve it in the two-component simulated oil of asphaltene-resin to obtain a three-component simulated oil of asphaltene-resin-wax.

[0043] The successfully prepared simulated oil was mixed with deionized water at an oil-water ratio of 7:3, and stirred at high speed for 2 minutes at a speed of 10000 r / min using a WIGGENS D-500 high-speed homogenizer to obtain a three-component heavy oil simulated emulsion consisting of asphaltene, resin, and wax.

[0044] Example 7: Preparation of blank heavy oil simulated emulsion A blank simulated oil was prepared by mixing toluene and non-polar aviation kerosene at a mass ratio of 1:1. The prepared simulated oil was then mixed with deionized water at an oil-water ratio of 7:3. The mixture was stirred at high speed for 2 minutes at 10,000 r / min using a WIGGENS D-500 high-speed homogenizer to obtain a blank heavy oil simulated emulsion.

[0045] Example 8: Stability evaluation of heavy oil simulated emulsion Water separation rate test The simulated heavy oil emulsions prepared in Examples 1, 4, 5, 6, and 7 were quantitatively placed into 25 ml graduated colorimetric tubes. The oil-water separation time and volume distribution of each phase in the colorimetric tubes were observed and recorded. The observation period was approximately 7 days. The test results are as follows: Figure 4 As shown.

[0046] Viscoelastic membrane test The viscoelasticity of the oil-water interface of the heavy oil simulated emulsions prepared in Examples 1, 4, 5, 6, and 7 was tested using a KRUSS DSA100 fully automatic interfacial tensiometer at room temperature and pressure, and with a measurement frequency range of 0.1-1Hz, via the oscillating droplet method. The test results are shown in the figures below. Figure 5 , 6 7, 8.

[0047] Microscopic observation of emulsions The microscopic droplet size of the viscous oil simulated emulsions prepared in Examples 1, 4, 5, 6, and 7 was observed using an XP-3800 optical microscope at a scale of 100 μm. The test results are as follows: Figure 9 As shown.

[0048] Evaluation of the effect of heavy oil simulated emulsion The evaluation results of the influence of different crude oil components on the stability of heavy oil simulated emulsions are shown in Table 2. Experimental data show that in the emulsion viscoelastic film test, Example 7 (blank simulated emulsion) failed to form a stable oil-water interface film, indicating insufficient emulsion stability. The water separation rate determination experiment showed that Example 7 rapidly separated oil and water after standing, indicating low interface stability and a significant separation tendency. In the microparticle size analysis test, Example 7 exhibited a large number of large droplets formed by aggregation, attributed to its lack of a sufficiently strong interface film structure. Further experiments revealed that only after adding heavy components such as asphaltene could the simulated oil system form a stable emulsion, exhibiting appropriate dilatational modulus, water separation volume, and a relatively reasonable particle size distribution range. These results confirm that, based on the construction of a pure solvent benchmark system without its own emulsification ability, this invention can quantitatively distinguish the specific contributions of different crude oil components to the stability of heavy oil emulsions through three dimensions: interface modulus, water separation volume, and microparticle size. This demonstrates high operability and repeatability, providing a reliable and controllable experimental platform for in-depth research on heavy oil demulsification.

[0049] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the contents disclosed in the present invention and are all within the protection scope of the present invention.

[0050] Table 2 Evaluation of the impact of different crude oil components on the stability of heavy oil simulated emulsions .

Claims

1. A method for preparing simulated oil for evaluating the impact of ultra-heavy oil emulsion stability, characterized in that, The method includes: crude oil pretreatment and residual oil acquisition, asphaltene separation and recovery, wax separation and recovery, gum separation and recovery, construction of simulated oil-based liquid and component remixing, and preparation of simulated oil emulsion. Preferably, during crude oil pretreatment and residual oil acquisition, the condensate distillation rate of the distillation flask is maintained at 2.0 mL / min to 2.5 mL / min, and heating is stopped when the distillation temperature reaches 250°C. Preferably, n-hexane is used to dissolve the residual oil. Preferably, during wax separation and recovery, the n-hexane filtrate is concentrated to 10 ml, 60 ml of benzene-acetone mixed solution is added, 10 ml of dewaxing agent is used, and the dewaxing filtration environment temperature is -20°C. Preferably, the mass ratio of toluene to non-polar aviation kerosene in the simulated asphaltene oil is 1:

1. Preferably, the oil-water mixing ratio of the simulated oil to deionized water is 7:

3. Preferably, the high-speed homogenizer operates at a speed of 10000 r / min, and the stirring time is 2 min.

2. The method for efficiently separating key components of crude oil and preparing a heavy oil simulated emulsion as described in claim 1, firstly, crude oil pretreatment and residual oil acquisition are performed: the crude oil sample is transferred to a pre-weighed distillation apparatus and heated steadily until the sample boils, the distillation rate is controlled within 2.0 mL / min to 2.5 mL / min, distillation is stopped when the temperature reaches 250°C, and residual oil is obtained after cooling.

3. Asphalt separation and recovery: Weigh the residual oil sample and add the specified amount of n-hexane according to Table 1. After dissolving it completely, filter it by the light purging method and dry it to collect the asphalt particles.

4. Wax Separation and Recovery: The hexane filtrate was collected and concentrated to 10 ml. 60 ml of a benzene-acetone mixed solution was added, and the wax was dewaxed three times (10 ml / time) using a dewaxing agent at an ambient temperature of -20°C, followed by suction filtration. The wax was dissolved in hot petroleum ether, and the solvent was evaporated. The wax component was then dried under vacuum to obtain the wax fraction.

5. Separation and recovery of colloids: The benzene-acetone filtrate from step 4 is collected in a beaker, concentrated and dried in a fume hood, and left to stand in the dark for 5-6 hours to obtain crude colloids.

6. Construction and component remixing of simulated oil-based fluid: Using a composite matrix of toluene and non-polar aviation kerosene as a carrier (the mass ratio of toluene to non-polar aviation kerosene is 1:1), the key components (asphaltite / colloids / wax) extracted in steps 3, 4 and 5 are quantitatively remixed according to a preset ratio to construct a simulated oil system.

7. Preparation of simulated oil emulsion: Mix the simulated oil prepared in step 6 with deionized water at an oil-to-water ratio of 7:3, and use a high-speed homogenizer to homogenize and emulsify at a speed of 10,000 r / min and a stirring time of 2 min to obtain a heavy oil simulated emulsion.

8. The method for efficiently separating key components of crude oil and preparing a simulated heavy oil emulsion as described in claim 1, by pre-dissolving asphaltenes with toluene to form a stable solvated shell, and then introducing non-polar aviation kerosene to simulate the dilution environment of light components on heavy components in heavy oil, thereby reconstructing a colloidal stable structure similar to that of real crude oil at the microscopic level.

9. The method for efficiently separating key components of crude oil and preparing a heavy oil simulated emulsion as described in claim 1, characterized in that: The simulated heavy oil emulsions containing different crude oil components prepared using the method described in claim 1 can be quantitatively characterized and differentiated in terms of the specific contributions of different crude oil components to the stability of heavy oil emulsions through three dimensions: interfacial viscoelastic modulus, water separation volume, and microscopic particle size. This provides a reliable and controllable experimental platform for in-depth research on heavy oil demulsification. The results of the stability impact evaluation are shown in Table 2.

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