Extra-super heavy oil asphaltene subcomponent separation method

Abstract

The invention belongs to the field of oil and gas field surface engineering, and discloses an ultra-heavy oil asphaltene subcomponent separation method, which comprises the following steps: dividing crude oil into three components, namely oil, colloid and asphaltene, separating asphaltene from turbid liquid of green matter precipitates or colloid precipitates under different toluene or acetone concentrations by changing the proportion of toluene to acetone, standing, centrifuging, and separating the asphaltene from the turbid liquid of the green matter precipitates or the colloid precipitates under different toluene or acetone concentrations; and pouring out the supernatant, and carrying out vacuum drying to respectively obtain different subcomponents of the asphalt. By changing the proportion of toluene and acetone, asphaltene precipitates under different toluene or acetone concentrations are obtained, five subcomponents of asphaltene can be obtained respectively, the effect of asphaltene without using subcomponents can be reflected more intuitively and clearly, and the method has the advantages of simplicity, convenience and rapidness in operation. The development of the asphaltene subcomponent separation technology provides important information for further research and application of asphalt materials, and also provides important technical support for analysis and evaluation of the quality of petroleum asphalt.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field surface engineering and provides a method for separating original asphaltene subcomponents, specifically relating to a method for separating asphaltene subcomponents in extra-heavy oil. Background Technology

[0002] Asphaltenes subcomponent separation is an important aspect of asphaltenes chemistry research, involving the extraction and analysis of different components within asphaltenes. According to search results, various methods exist for separating asphaltenes subcomponents, including physical, chemical, and biological methods.

[0003] Asphaltenes are complex mixtures primarily composed of high-molecular-weight hydrocarbons and diffractions from non-metallic materials. These mixtures include heteroatoms (such as nitrogen, sulfur, and oxygen), heavy metals (such as vanadium, nickel, and iron), and polycyclic aromatic hydrocarbons. Asphaltenes are soluble in benzene or toluene but insoluble in alkanes. During petroleum production, changes in chemical composition due to factors such as air pressure and temperature can significantly impair the colloidal stability of asphaltenes, leading to substantial deposition and causing serious consequences such as formation damage and reduced well productivity. To better understand the properties of asphaltenes and explore their adsorption, aggregation, and precipitation, subcomponent separation and characterization analysis are crucial. However, current domestic and international standards for asphaltenes subcomponent structural analysis lack uniformity and have certain limitations.

[0004] CN111575048A describes a method for separating asphaltenes from crude oil. By gradually increasing the proportion of a precipitant, the asphaltenes are induced to separate from crude oil or asphalt based on their varying stability. This method can simulate the gradual loss of unstable asphaltenes from crude oil underground, providing assistance for studying the hazards of asphaltenes in petroleum production and the changes in elements, isotopes, and characteristic compounds in oil and gas geochemical research. However, the solvent used in this separation method is only applicable to crude oil, limiting its applicability. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies and address the current limitations of the lack of unified standards for the analysis of asphaltene subcomponent structures both domestically and internationally, this invention obtains asphaltene precipitation at different toluene or acetone concentrations by changing the ratio of toluene and acetone. This allows for the separate determination of the five subcomponents of asphaltene, providing a more intuitive and clear reflection of the roles of each subcomponent. The development of asphaltene subcomponent separation technology provides important information for further research and application of asphalt materials, and also offers crucial technical support for the quality analysis and evaluation of petroleum asphalt.

[0006] Asphaltene subfractions were separated by polarity using solubility-based methods. These subfractions exhibited different types of side chain lengths and quantities; decreasing polarity resulted in better dispersion and a weaker tendency to aggregate. Following a process of dissolution, stirring, settling, filtration, extraction, distillation, and vacuum drying, crude oil was separated into three components: oil, resins, and asphaltene. The resulting asphaltene was then used to prepare suspensions of asphaltenes or resins at different toluene or acetone concentrations. By varying the toluene-acetone ratio, the suspensions were allowed to settle, centrifuged, and the supernatant was discarded and vacuum dried to obtain the five asphalt subfractions.

[0007] The above-mentioned objective of this invention is achieved through the following technical solution:

[0008] A method for separating asphaltene subcomponents in extra-heavy crude oil involves separating crude oil into three components: oil, gum, and asphaltene. Suspensions of asphaltene or gum precipitates at different toluene or acetone concentrations are separated by changing the ratio of toluene to acetone. After standing, the mixture is centrifuged, the supernatant is poured off, and vacuum dried to obtain the different asphalt subcomponents.

[0009] Furthermore, the process of separating crude oil into three components—oil, gum, and asphaltenes—includes dissolution, filtration, extraction, distillation, and vacuum drying.

[0010] Furthermore, during the separation of asphaltene, the material is first weighed, then refluxed and allowed to settle, followed by rinsing and filtration, extraction and cooling, and distillation and drying.

[0011] Furthermore, when weighing asphaltene, the solvent toluene to asphaltene solvent ratio is 30 to 90:1.

[0012] Furthermore, the time for asphalt refluxing and static sedimentation was 0.8-1.5 h.

[0013] Furthermore, the solvent for rinsing the asphalt is n-heptane, and the amount used is 8-10 mL.

[0014] Furthermore, after the asphaltene extraction and cooling, 20-60 mL of toluene is added, and extraction continues.

[0015] Furthermore, the separation method for one of the different subcomponents of asphalt is as follows: after preparing the asphalt subcomponent into a toluene solution and letting it stand, the supernatant is poured out, the supernatant containing residual gum precipitate is centrifuged, the supernatant after centrifugation is mixed with the supernatant poured out first, the precipitate is vacuum dried and weighed to obtain asphaltene A1.

[0016] Continue adding acetone to the mixed solution and repeat the above operation to obtain asphaltene A2.

[0017] Repeat the process, adding acetone to the mixed solution, and continue the above operation to obtain asphaltene A3.

[0018] Repeat the process, adding acetone to the mixed solution, and continue the above steps to obtain asphaltene A4.

[0019] The liquid in the bottle was evaporated and dried to obtain asphalt A5.

[0020] The advantages of this invention compared to the prior art are:

[0021] Asphaltenes are among the most complex and highest molecular weight components in crude oil, and their properties determine the colloidal stability, extraction, and gathering of crude oil. However, due to their complex composition and diverse molecular types, it is necessary to further separate them to obtain subcomponents with different compositions. This method provides a component separation approach for further research and understanding of asphaltenes. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 This is a flowchart of the solvent separation method for separating crude oil components in Example 1;

[0024] Figure 2 This is a flowchart of the solvent separation method for separating asphaltenes subcomponents in Example 2. Detailed Implementation

[0025] 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.

[0026] Example 1

[0027] The crude oil was separated into three components—oil, resin, and asphaltenes—through a process of dissolving, stirring, settling, filtering, extraction, distillation, and vacuum drying. For details of the separation process, please refer to [link to relevant documentation]. Figure 1 .

[0028] Example 2

[0029] Suspensions of asphaltenes or gum precipitates at different toluene or acetone concentrations were obtained by varying the toluene-to-acetone ratio. This utilizes the polarity of acetone, and the asphaltenes are further separated based on their acetone content. Asphaltenes with higher acetone content exhibit stronger polarity in the solvent separation, resulting in asphaltenes subcomponents with different polarities. After standing, the mixture was centrifuged, the supernatant was poured off, and vacuum dried to obtain five asphaltenes. The specific separation process is detailed in [link to documentation]. Figure 2 .

[0030] Asphaltene separation: First, roughly weigh about 3 grams of the crude oil from the isolated island into a 250 mL Erlenmeyer flask (flask No. 1), then transfer it to an analytical balance and weigh it accurately. Dissolve the 3 g of crude oil in 120 mL of n-heptane. Set up a reflux apparatus, set the temperature to 105℃, and start heating. Start timing from the appearance of reflux, and reflux for 1 hour. After cooling, place it in the dark and let it stand for another 1 hour to allow the asphaltene to precipitate more completely. Then, perform filtration (using medium-speed quantitative filter paper). After all the filtrate has been poured onto the filter paper, rinse the remaining asphaltene in the flask several times with hot n-heptane (70℃). Note: The amount of n-heptane used for rinsing should not be excessive, approximately 10 mL. Set up the extraction apparatus again, setting the temperature to 105℃. Extract the filtered solute onto the filter paper and reflux until the liquid becomes colorless. Allow it to cool and remove it. Add 40 mL of toluene to flask #1 and continue extraction onto the filter paper at 130℃ until the liquid becomes colorless. Stop reflux. Set up a distillation apparatus at 130℃ and distill the toluene solvent from flask #1. Recover the solvent and place flask #1 in a vacuum drying oven at 30℃ to dry, thus obtaining asphaltenes. This provides a sample for further asphaltenes separation.

[0031] Asphaltenes subcomponent separation: Suspensions of asphaltenes precipitated with different concentrations of toluene or acetone were centrifuged after standing by varying the toluene-acetone ratio. The supernatant was then poured off and vacuum dried to obtain five asphaltenes subcomponents. The specific separation process is as follows: The asphaltenes subcomponents were prepared into a 2.5% toluene solution and allowed to stand for 2 hours to fully dissolve. Then, a 75% toluene solution was prepared using a toluene-acetone ratio of 7.5:2.5 (the ratio can be modified, as different ratios will change the content and composition of the subcomponents). The solution was allowed to stand for 24 hours, and the supernatant was poured off. The remaining supernatant was then poured into centrifuge tubes and centrifuged at 2000 rpm. -1 Centrifuge at a certain speed for 2 hours. Mix the supernatant after centrifugation with the previously poured-out supernatant. Vacuum dry the precipitate and weigh it to obtain asphaltene A1. Continue to add acetone to the mixed solution to make a toluene-acetone ratio of 6:4, preparing a toluene solution with a mass fraction of 60%. Continue the above operation to obtain asphaltene A2. Repeat the operation, continue to add acetone to the mixed solution to make a toluene-acetone ratio of 4:6, preparing a toluene solution with a mass fraction of 40%. Continue the above operation to obtain asphaltene A3. Repeat the operation, continue to add acetone to the mixed solution to make a toluene-acetone ratio of 2:8, preparing a toluene solution with a mass fraction of 20%. Continue the above operation to obtain asphaltene A4. Evaporate and dry the liquid in the bottle to obtain asphaltene A5.

[0032] A type of crude oil from the Liaohe Oilfield was based on Figure 1 The separation method was used to obtain the contents of the three components, as shown in Table 1.

[0033] Table 1 Content of the three components of crude oil

[0034]

[0035] Based on the difference in the relative proportions of toluene and acetone, according to Figure 2 The separation method will divide the asphalt into sub-components A1 to A5. The content of each sub-component is shown in Table 2.

[0036] Table 2 Content of five components of asphaltene

[0037]

[0038]

[0039] 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 separating subcomponents of asphaltenes in extra-heavy oil, characterized in that, Crude oil was separated into three components: oil, gum, and asphaltenes. Suspensions of asphaltenes or gums at different toluene or acetone concentrations were separated by changing the ratio of toluene to acetone. After standing, the suspensions were centrifuged, the supernatant was poured off, and the suspensions were vacuum dried to obtain different subcomponents of asphalt.

2. The method for separating asphaltene subcomponents in extra-heavy oil according to claim 1, characterized in that, The process of separating crude oil into three components—oil, gum, and asphaltenes—includes dissolution, filtration, extraction, distillation, and vacuum drying.

3. The method for separating asphaltene subcomponents in extra-heavy oil according to claim 1, characterized in that, When separating asphaltene, the material is first weighed, then refluxed and allowed to settle, washed and filtered, extracted and cooled, and then distilled and dried.

4. The method for separating asphaltene subcomponents in extra-heavy oil according to claim 3, characterized in that, When weighing asphaltene, the solvent toluene ratio to asphaltene is 30–90:

1.

5. The method for separating asphaltene subcomponents in extra-heavy oil according to claim 3, characterized in that, The time for asphalt refluxing and static sedimentation was 0.8-1.5 h.

6. The method for separating asphaltenes from extra-heavy oil according to claim 3, characterized in that, The solvent for rinsing asphalt is n-heptane, and the amount used is 8-10 mL.

7. The method for separating asphaltene subcomponents in extra-heavy oil according to claim 3, characterized in that, After the asphaltene extraction is cooled, add 20-60 mL of toluene and continue extraction.

8. The method for separating subcomponents of extra-heavy oil asphalt according to claim 1, characterized in that the asphalt... The separation method for one of the different subcomponents is as follows: after preparing the asphaltene subcomponent into a toluene solution and letting it stand, pour out the supernatant, centrifuge the supernatant containing the residual gum precipitate, mix the supernatant after centrifugation with the first poured-out supernatant, vacuum dry the precipitate and weigh it to obtain asphaltene A1.

9. The method for separating asphaltene subcomponents in extra-heavy oil according to claim 8, characterized in that, Continue adding acetone to the mixed solution and repeat the above operation to obtain asphaltene A2.

10. The method for separating asphaltene subcomponents in extra-heavy oil according to claim 9, characterized in that, Repeat the process, adding acetone to the mixed solution, and continue the above operation to obtain asphaltene A3.

11. The method for separating asphaltene subcomponents in extra-heavy oil according to claim 9, characterized in that, Repeat the process, adding acetone to the mixed solution, and continue the above steps to obtain asphaltene A4.

12. The method for separating asphaltene subcomponents in extra-heavy oil according to claim 11, characterized in that, The liquid in the bottle was evaporated and dried to obtain asphalt A5.

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