Asphaltic bitumen-like sheet and method for its production

Abstract

The application discloses an asphaltene sample and a preparation method thereof, and belongs to the technical field of oil field chemicals. The preparation method of the asphaltene sample comprises the following steps: asphaltene extraction; and pressing the extracted asphaltene into a sheet to obtain the asphaltene sample. The asphaltene extraction comprises the following steps: adding a first solvent into asphaltene extraction raw materials to perform heating reflux, standing, and filtering to obtain filter paper with insoluble substances; adding the first solvent into the filter paper with the insoluble substances to perform reflux extraction; adding a second solvent to perform heating reflux after the reflux is completed; and removing the second solvent to obtain the extracted asphaltene. The preparation method of the asphaltene sample specifically describes a method for extracting asphaltene from residual oil or wellhead blockage, and clearly defines the operation conditions of the asphaltene when being pressed into a sheet; and is suitable for analyzing, evaluating and screening asphaltene dispersants.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemical technology, specifically to an asphalt sample and its preparation method. Background Technology

[0002] Asphaltenes are complex macromolecular organic compounds, commonly found in natural resources such as petroleum and coal tar. They consist of numerous aromatic rings, cycloalkane rings, and heterocycles, with long-chain alkyl side chains, exhibiting high cross-linking and polymerization, resulting in high molecular weight and complex chemical properties. Physically, asphaltenes are typically black or brown solids with high viscosity and density. They are insoluble in low-molecular-weight organic solvents, such as n-hexane, but soluble in some aromatic hydrocarbon solvents, such as benzene and toluene.

[0003] Asphaltenes and other recombinants in crude oil can aggregate and clog oil pipes or surface pipelines, leading to frequent incidents such as sudden drops in production, wellbore failures, or surface pipe bursts. From the perspective of oilfield chemical usage, using asphaltenes-based dispersants and unblocking agents is a better choice. However, there is still no universally accepted industry standard for evaluating asphaltenes-based dispersants and unblocking agents. The most fundamental problem is that there are no standard samples of the research object, namely asphaltenes.

[0004] The composition of blockages at different sites is complex, ranging from those with higher inorganic content to those with higher wax content; their forms vary, including powder, flakes, lumps, or pastes. Due to the heterogeneity and complexity of the blockages, it is difficult to reproduce the laboratory evaluation results of asphaltene dispersants during on-site sampling and analysis. This makes it impossible for laboratory experiments to guide on-site construction, and even leads to significant discrepancies in evaluation results from different laboratories during the screening and evaluation process, resulting in a substantial waste of human, material, and time resources. Therefore, it is of great significance to invent a method for preparing asphaltene sample pieces, standardize the asphaltene extraction method, and prepare sample pieces from the extracted asphaltene using uniform operating conditions to reduce experimental errors, thereby improving experimental efficiency, reducing resource waste, and guiding on-site practice. Summary of the Invention

[0005] The purpose of this invention is to provide an asphalt sample and its preparation method, which fills the gap in the prior art where there are no standard samples of asphalt.

[0006] To achieve the above objectives, one embodiment of the present invention provides a method for preparing asphalt sample sections, comprising the following steps:

[0007] Asphalt extraction;

[0008] The extracted asphalt was pressed into sheets to obtain asphalt sample sheets;

[0009] Asphalt extraction includes:

[0010] Add the first solvent to the asphalt extract raw material, heat and reflux, let stand, filter, and obtain filter paper with insoluble matter;

[0011] The first solvent was added to the filter paper containing insoluble matter and refluxed for extraction. After reflux, the second solvent was added and heated for reflux. The second solvent was then removed to obtain the extracted asphalt.

[0012] One preferred embodiment of the present invention is to compress the extracted asphalt into sheets to obtain asphalt sample sheets, comprising: placing the extracted asphalt inside a mold, applying pressure to the mold and stabilizing the pressure, replacing the bottom mold after stabilization, and extruding the sample sheets to obtain asphalt sample sheets.

[0013] In one preferred embodiment of the present invention, water is dripped into the mold and the bitumen before pressure is applied to the mold.

[0014] One preferred embodiment of the present invention involves adding a first solvent to the asphalt extraction raw material, heating and refluxing, allowing it to stand, and filtering to obtain filter paper containing insoluble matter, comprising:

[0015] Add the first solvent to the asphalt extract and heat under reflux for 55-65 minutes. After the reflux is complete, let it stand for 90-150 minutes. Filter the solvent after standing to obtain filter paper with insoluble matter.

[0016] In one preferred embodiment of the present invention, the asphalt extraction raw material includes residual oil and blockage material, wherein the residual oil is obtained from crude oil.

[0017] In one preferred embodiment of the present invention, a first solvent is added to filter paper containing insoluble matter for reflux extraction. After reflux, a second solvent is added and the mixture is heated and refluxed to remove the second solvent, thereby obtaining the extracted asphaltene, comprising:

[0018] Add the first solvent to the filter paper containing insoluble matter and perform reflux extraction;

[0019] After reflux extraction, a second solvent is added and the mixture is heated under reflux.

[0020] After heating to reflux is complete, the second solvent is removed by distillation.

[0021] After the second solvent removal is completed, the extracted asphalt is obtained by drying.

[0022] In one preferred embodiment of the present invention, the reflux extraction time is ≥60 min, and the dripping rate of the first solvent during the reflux extraction process is controlled to be 2 drops / s-4 drops / s.

[0023] In one preferred embodiment of the present invention, the amount of the second solvent added is 50 mL to 100 mL.

[0024] In one preferred embodiment of the present invention, drying includes maintaining a temperature of 100℃-110℃ and a negative pressure of 53.3kPa-66.7kPa for 40min-80min.

[0025] In one preferred embodiment of the present invention, the first solvent is n-heptane solvent and the second solvent is toluene.

[0026] In one preferred embodiment of the present invention, the pressure for pressing the sheet is 3MPa-5MPa.

[0027] The present invention also discloses an asphalt sample, which is prepared by the above-described preparation method.

[0028] In one preferred embodiment of the present invention, the specifications of the asphalt sample include: a diameter of 9.9mm-10.1mm, a thickness of 4mm-5mm, and a mass of 0.45g-0.55g.

[0029] In summary, the beneficial effects of the present invention are as follows:

[0030] 1. The preparation method of the asphalt sample of the present invention achieves standardization of the prepared asphalt sample by controlling the extraction of asphalt, the use of molds and the pressing conditions, thereby improving the accuracy of the experimental process and facilitating the study of the solubility, dispersion and other properties of asphalt.

[0031] 2. The preparation method of the asphaltene sample of this invention elaborates on the method of extracting asphaltene from residual oil or wellhead blockage, and clarifies the operating conditions when asphaltene is pressed into sheets; it is applicable to the analysis, evaluation and screening of asphaltene dispersants, and the principle of this invention is reliable, the raw materials are widely available, the operation method is simple, and it has a positive and important impact on the evaluation of asphaltene dispersants and unblocking agents.

[0032] 3. Compared to the uneven and random composition of blockages, the asphalt extraction method provided by this invention can guarantee the purity of asphalt.

[0033] 4. Compared to arbitrary sheet preparation or the formation of blockage balls, this invention uses an asphalt-based sample mold and controls the pressing operation conditions, standardizing the sample preparation conditions and the size and model of the finished sheet, thus avoiding experimental errors introduced by the sample preparation process.

[0034] 5. The method for preparing asphalt samples in this invention avoids the experimental uncertainties caused by the complex and uneven composition of wellhead plugs, and standardizes the experimental conditions in the asphalt sample preparation process.

[0035] 6. In the preparation method of asphalt sample, the dried asphalt is brittle during the pressing process, resulting in an incomplete shape of the pressed sample. Therefore, this invention avoids the asphalt sample being loose and brittle by dripping water onto the mold and asphalt before applying pressure to the mold.

[0036] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention will be apparent from the effects described in the description and the accompanying drawings. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the tableting state when the diameter of the asphalt mold is 5 mm in Example 1 of the present invention;

[0038] Figure 2 This is a schematic diagram of the tableting state when the diameter of the asphalt mold is 25 mm in Example 1 of the present invention;

[0039] Figure 3 This is a schematic diagram showing the tablet thickness when the amount of asphalt added is 1g in Example 2 of the present invention.

[0040] Figure 4 This is a schematic diagram showing the tablet thickness when the amount of asphalt added is 0.5g in Example 2 of the present invention.

[0041] Figure 5 This is a graph showing the effect of adding water on the integrity of the sample in Example 4 of this invention.

[0042] Figure 6 This is a graph showing the effect of adding n-heptane solvent on the integrity of the sample in Example 4 of this invention;

[0043] Figure 7 This is a graph showing the effect of adding ethanol on the integrity of the sample in Example 4 of this invention.

[0044] Figure 8 This is a schematic diagram illustrating the inability to prepare standardized sample pieces for Comparative Example 1 of the present invention.

[0045] Figure 9 This is a schematic diagram of the wax-containing high-quality sample of Comparative Example 2 of the present invention solidifying into a block at room temperature. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0048] This invention provides a method for preparing asphalt sample sections, comprising the following steps:

[0049] Step (1): Asphalt extraction; including the following steps:

[0050] Step (101): Add the first solvent to the asphalt extract raw material, heat and reflux, let stand, and filter to obtain filter paper with insoluble matter; specifically, it includes the following steps:

[0051] Step (1011): Select asphaltene extraction raw materials. When the source of asphaltene is crude oil, prepare residual oil by distillation for asphaltene extraction. When the source of asphaltene is on-site blockage material, directly weigh the on-site blockage material for asphaltene extraction.

[0052] Step (1012): Place the asphalt extract raw material (residual oil sample or weighed field blockage material) processed in step (1011) into a round-bottom glass flask, and add the first solvent to the round-bottom glass flask containing the asphalt extract raw material. The first solvent is n-heptane solvent, and the amount of n-heptane solvent added is shown in Table 1.

[0053] Table 1: Sample Amount of Residual Oil or Blockage, Round Bottom Flask Specifications, and Amount of n-Heptane Solvent Used

[0054] residual oil or blockage mass / g Round bottom glass flask specifications / mL n-Heptane solvent volume / mL 12-18 1000 360-540 5-10 500 150-300

[0055] Step (1013): Connect the round-bottom glass flask to the extraction tube and condenser, place it on the electric heating mantle, turn on the cooling water, and heat under reflux for 55-65 minutes;

[0056] Step (1014): Stop heating, wait for the solution to cool, remove the round-bottom glass flask, stopper it, and let it stand in the dark for 90-150 minutes;

[0057] Step (1015): Filter by pouring over a glass funnel containing quantitative filter paper without stirring. Wash the residue in the round-bottom glass flask with a small amount of hot n-heptane solvent and place it on the filter paper to obtain filter paper with insoluble matter.

[0058] Step (102): Add the first solvent to the filter paper containing insoluble matter and reflux extraction. After reflux, add the second solvent and heat reflux to remove the second solvent, obtaining the extracted asphaltene; specifically, it includes the following steps:

[0059] Step (1021): Fold the filter paper with insoluble matter obtained in step (101), put it into the extraction tube, add 50 mL of n-heptane solvent (first solvent) to another 150 mL round bottom glass flask for reflux extraction, control the dripping speed of n-heptane solvent from the end of the cooler to be 2 drops / s-4 drops / s, and the reflux extraction time to be no less than 60 min, to remove the oil wax and gum mixed in the asphalt to obtain insoluble matter;

[0060] Step (1022): After the reflux extraction is complete, cool it slightly, remove the round-bottom glass flask, add 50mL-100mL of toluene (second solvent) to the 150mL round-bottom glass flask, and connect the round-bottom glass flask to the extraction tube and condenser. Continue to heat and reflux the insoluble matter in step (1021) on the electric heating mantle until all the asphalt on the filter paper in the extraction tube is dissolved in the toluene.

[0061] Step (1023): After the round-bottom glass flask has cooled, remove the round-bottom glass flask and place it in a 120℃ oil bath in a fume hood to distill off the solvent toluene. Then transfer it to a vacuum drying oven and maintain it at a temperature of 100℃-110℃ and a negative pressure of 53.3kPa-66.7kPa for 40min-80min. Remove it and place it in a desiccator to cool for later use, and obtain the extracted asphaltene.

[0062] Step (2): The extracted asphalt is pressed into sheets to obtain asphalt sample sheets; specifically, this includes the following steps:

[0063] Step (201): Weigh 0.3g-0.6g of the extracted asphalt and place it inside the asphalt sample preparation mold, and install the mold; preferably, the amount of extracted asphalt is 0.4g-0.55g, and further, the amount of extracted asphalt is 0.5g;

[0064] Step (202): Use a manual hydraulic press to slowly apply pressure to the mold until the pressure is 3MPa-5MPa, start timing, and stabilize the pressure for 8min-12min; preferably, the pressure is 4MPa, and the stabilization time is preferably 10min;

[0065] Step (203): After the stabilization time is reached, replace the bottom mold and slowly apply pressure to extrude the sample to obtain a complete sample. The preparation of the asphalt sample is completed.

[0066] Before applying pressure to the mold, water is dripped onto the mold and the asphalt material to prevent the extruded asphalt sample from becoming loose and brittle. The reason for adding water to wet the mold and the asphalt material is that the dried asphalt material is brittle during the pressing process, resulting in an incomplete shape of the extruded sample.

[0067] The method for preparing asphalt samples in this invention standardizes the prepared asphalt samples by controlling the extraction of asphalt, the use of molds, and the pressing conditions, thereby improving the accuracy of the experimental process and facilitating the study of the solubility, dispersion, and other properties of asphalt.

[0068] The preparation method of asphalt sample of this invention avoids the experimental uncertainties caused by the complex and uneven composition of wellhead plugging material, and standardizes the experimental conditions in the preparation process of asphalt sample. Compared with the greater randomness of the uneven composition of plugging material, the asphalt extraction method provided by this invention can ensure the purity of asphalt. Compared with random sample preparation or making plugging material balls, this invention standardizes the sample preparation conditions and the size and model of the finished sample by using an asphalt sample mold and controlling the pressing operation conditions, thus avoiding experimental errors introduced by the sample preparation process.

[0069] The present invention also discloses an asphalt sample, which is prepared by the above-described preparation method. The specifications of the prepared asphalt sample include: a diameter of 9.9 mm-10.1 mm, a thickness of 4 mm-5 mm, and a mass of 0.45 g-0.55 g.

[0070] Preparation Example 1

[0071] Determining the diameter of the asphalt mold during the asphalt tableting process:

[0072] The diameter of the bituminous pressing mold was determined by using pressing molds with diameters of 5 mm, 25 mm, and 10 mm, respectively. The specific experimental results are as follows:

[0073] When a 5mm diameter compression mold is used and the pressure is 1MPa, the compression mold deforms even with a very small sample volume, as shown in the following results. Figure 1 As shown; when a 25mm diameter compression mold is used, the compressed tablets are thin and fragile, as shown in the following results. Figure 2 As shown; when a 10mm diameter pressing mold is selected, the pressed tablet has a certain strength;

[0074] Based on the above experimental results, it can be concluded that a 10mm diameter tablet pressing mold should be used for tablet pressing.

[0075] Preparation Example 2

[0076] Determining the mass of asphalt sample added during asphalt tableting:

[0077] Based on Preparation Example 1, asphaltene tablets were prepared using a pressing mold with a direct diameter of 10 mm. 1 g and 0.5 g of the extracted asphaltene were weighed to determine the sample loading mass. The specific experimental results are as follows:

[0078] When the amount of asphalt sample added is 1g, the tablet thickness is about 10mm. Due to the significant friction with the tablet forming mold, it is prone to breakage, resulting in the following: Figure 3 As shown; when the amount of asphalt added is 0.5g, the tablet thickness is suitable and not easily broken, and the tablet thickness is between 4.5mm and 5.0mm, which is convenient for preparation, such as... Figure 4 As shown;

[0079] Based on the above experimental results, the amount of asphalt added should be 0.5g.

[0080] Preparation Example 3

[0081] Determining the applied pressure during asphalt tableting:

[0082] Based on Preparation Example 1 and Preparation Example 2, asphalt tablets were prepared using a pressing mold with a direct diameter of 10 mm. The amount of asphalt added was 0.5 g. The tablets were pressed and stabilized for 10 min at pressures of 1 MPa, 2 MPa, 3 MPa, 4 MPa and 5 MPa, respectively. The pressure determination experiment was conducted, and the experimental results are shown in Table 2.

[0083] Table 2: Sample thickness and sample mass under different pressures

[0084]

[0085] As can be seen from Table 2, when the applied pressure is between 3MPa, 4MPa and 5MPa, the thickness and weight of the asphalt tablets tend to be the same. In order to ensure that the pressure value fluctuates within a certain range and does not affect the results, it is determined that a pressure of 4MPa should be applied for tableting.

[0086] Preparation Example 4

[0087] Solution to sample breakage during asphalt tableting process:

[0088] During the pressing experiment of asphalt samples, it was found that the dried asphalt was brittle during pressing, resulting in incomplete tablet shape. Therefore, an experiment was designed to wet the mold and asphalt with water, n-heptane solvent, and ethanol respectively before applying pressure to the mold. Figure 5 , Figure 6 and Figure 7 As shown, where Figure 5 The results were obtained after wetting with water. Figure 6 The result is after wetting with n-heptane solvent. Figure 7 The result is after wetting with ethanol.

[0089] from Figure 5 , Figure 6 and Figure 7 As can be seen, adding a small amount of water to wet the mold will prevent the tablets from breaking.

[0090] Preparation Example 5

[0091] Based on the preparation example 4 above, we will demonstrate whether wetting with water will affect the tableting results:

[0092] The specific operation is as follows: During the asphalt tableting process, the effects of adding wetting liquid on the tableting results are demonstrated by whether wetting liquid is added to wet the mold and asphalt, and by the amount of wetting liquid added. In particular, after adding water-based wetting liquid during the asphalt tableting process, the tablets need to be dried to reduce the impact of the water-based wetting liquid on the experimental results.

[0093] The experimental results are shown in Table 3:

[0094] Table 3: Results of the effect of different wetting solutions on solubility

[0095]

[0096] As can be seen from Table 3, adding water to wet the mold and asphalt during the asphalt tableting process has virtually no impact on the experimental results. Therefore, adding water to wet the mold and asphalt will not affect the experimental results.

[0097] Example 1

[0098] A method for preparing an asphalt sample, comprising the following steps:

[0099] Step (1): Asphalt extraction, asphalt is extracted through the blockage;

[0100] Specifically, the following steps are included:

[0101] Step (101): Weigh 20g of the blockage material into a 200mL round-bottom glass flask, add 100mL of n-heptane, stir until the blockage material has no lumpy structure, tighten the stopper and let it stand at room temperature for 8 hours;

[0102] Step (102): Use a vacuum circulating water pump to filter and remove the solution. Wash the residue with 50 mL of n-heptane to obtain n-heptane insoluble matter. Put it into a round-bottom glass flask, add 100 mL of toluene, stir thoroughly, filter again to remove toluene insoluble matter, and collect the toluene soluble filtrate.

[0103] Step (103): Place the filtrate from step (102) into a round-bottom glass flask and evaporate it in an oil bath at 130°C; after the toluene has basically evaporated, dry it in an oven at 110°C until all the toluene has evaporated to obtain the extracted asphalt.

[0104] Step (2): The extracted asphalt is pressed into sheets to obtain asphalt sample sheets; including the following steps:

[0105] Step (201): Crush the extracted asphalt to pass through the mold opening, filter it with a 100-mesh sieve to obtain asphalt for sample preparation;

[0106] Step (202): Weigh 0.50g of the asphalt used to make the sample in step (201) above, accurate to 0.01g, put it into the mold sample cup, and flatten it;

[0107] Step (203): Insert the stopper rod into the mold sample cup, place it on a manual hydraulic press, pressurize it at a constant speed to 4MPa, stabilize the pressure for 10 minutes, and then release the pressure;

[0108] Step (204): Take out the asphalt sample after it has been pressed into sheets, place it in a vacuum drying oven at 90℃ and 0.09MPa for 1 hour, cool it for 30 minutes, weigh it, and record the mass of the asphalt sample (accurate to 0.0001g).

[0109] If the asphalt sample is broken or not compact after being pressed into a sheet, a drop of deionized water is added to the mold using a 1mL syringe with a needle during preparation. After the sample is loaded, another drop of deionized water is added to moisten it before pressing. The reason for adding water to moisten the mold and asphalt is that the dried asphalt is fragile during the pressing process, resulting in an incomplete sheet shape.

[0110] Example 2

[0111] A method for preparing an asphalt sample, comprising the following steps:

[0112] Step (1): Asphalt extraction, asphalt is extracted from crude oil;

[0113] Specifically, the following steps are included:

[0114] Step (101): Weigh 100g of crude oil sample into a round-bottom glass flask, distill at atmospheric pressure until the liquid phase temperature reaches 260℃, and distill off the light components; leave the residual oil, and collect it after it cools to room temperature for asphaltene extraction;

[0115] Step (102): According to the residual oil mass, add n-heptane at a mass ratio of residual oil to n-heptane of 1:30. Connect the extractor and condenser to the mixture of residual oil and n-heptane, place it on the heating mantle, turn on the cooling water, and heat and reflux for 60 minutes.

[0116] Step (103): Stop heating, wait for the solution to cool, remove the round-bottom glass flask, stopper it, and let it stand in the dark for 100 minutes;

[0117] Step (104): Filter by pouring over a glass funnel containing quantitative filter paper without stirring. Wash the residue in the round-bottom glass flask with a small amount of hot n-heptane and place it on the filter paper.

[0118] Step (105): Fold the filter paper with insoluble matter, place it in the extractor, add 50 ml of n-heptane to another round-bottom glass flask and reflux extract, control the rate at which n-heptane drips from the end of the cooler to be 3 drops / s, reflux extract for 100 min, remove the oil, wax and gum mixed in the asphaltenes to obtain insoluble matter, until all the asphaltenes on the filter paper in the extractor are dissolved in toluene;

[0119] Step (106): After the round-bottom glass flask has cooled, remove the round-bottom glass flask and place it in a 130°C oil bath in a fume hood to distill off the solvent toluene. Then transfer it to a vacuum oven and keep it at 100°C and 60 kPa negative pressure for 60 min. Remove it and place it in a desiccator to cool for 40 min before weighing.

[0120] Step (107): Repeat the above steps until the collected bitumen is sufficient for sample preparation and analysis.

[0121] Step (2): The extracted asphalt is pressed into sheets to obtain asphalt sample sheets; including the following steps:

[0122] Step (201): Crush the extracted asphalt to pass through the mold opening, filter it with a 100-mesh sieve to obtain asphalt for sample preparation;

[0123] Step (202): Weigh 0.50g of the asphalt used to make the sample in step (201) above, accurate to 0.01g, put it into the mold sample cup, and flatten it;

[0124] Step (203): Insert the stopper rod into the mold sample cup, place it on a manual hydraulic press, pressurize it at a constant speed to 4MPa, stabilize the pressure for 10 minutes, and then release the pressure;

[0125] Step (204): Take out the asphalt sample after it has been pressed into sheets, place it in a vacuum drying oven at 90℃ and 0.09MPa for 1 hour, cool it for 30 minutes, weigh it, and record the mass of the asphalt sample (accurate to 0.0001g).

[0126] If the asphalt sample is broken or not compact after being pressed into a sheet, a drop of deionized water is added to the mold using a 1mL syringe with a needle during preparation. After the sample is loaded, another drop of deionized water is added to moisten it before pressing. The reason for adding water to moisten the mold and asphalt is that the dried asphalt is fragile during the pressing process, resulting in an incomplete sheet shape.

[0127] Example 3

[0128] A method for preparing an asphalt sample, comprising the following steps:

[0129] Step (1): Asphalt extraction, asphalt is extracted from crude oil;

[0130] Specifically, the following steps are included:

[0131] Step (101): Weigh 100g of crude oil sample into a round-bottom glass flask, distill at atmospheric pressure until the liquid phase temperature reaches 260℃, and distill off the light components; leave the residual oil, and collect it after it cools to room temperature for asphaltene extraction;

[0132] Step (102): According to the residual oil mass, add n-heptane at a mass ratio of residual oil to n-heptane of 1:30. Connect the extractor and condenser to the mixture of residual oil and n-heptane, place it on the electric heating mantle, turn on the cooling water, and heat and reflux for 65 minutes.

[0133] Step (103): Stop heating, wait for the solution to cool, remove the round-bottom glass flask, stopper it, and let it stand in the dark for 150 minutes;

[0134] Step (104): Filter by pouring over a glass funnel containing quantitative filter paper without stirring. Wash the residue in the round-bottom glass flask with a small amount of hot n-heptane and place it on the filter paper.

[0135] Step (105): Fold the filter paper with insoluble matter, place it in the extractor, add 50 ml of n-heptane to another round-bottom glass flask and reflux extract, control the rate at which n-heptane drips from the end of the cooler to be 4 drops / s, reflux extract for 80 min, remove the oil, wax and gum mixed in the asphaltenes to obtain insoluble matter, until all the asphaltenes on the filter paper in the extractor are dissolved in toluene;

[0136] Step (106): After the round-bottom glass flask has cooled, remove the round-bottom glass flask and place it in a 130°C oil bath in a fume hood to distill off the solvent toluene. Then transfer it to a vacuum oven and keep it at 110°C and 66.7 kPa negative pressure for 60 min. Remove it and place it in a desiccator to cool for 40 min before weighing.

[0137] Step (107): Repeat the above steps until the collected bitumen is sufficient for sample preparation and analysis.

[0138] Step (2): Press the extracted asphalt into sheets to obtain asphalt sample sheets;

[0139] Includes the following steps:

[0140] Step (201): Crush the extracted asphalt to pass through the mold opening, filter it with a 100-mesh sieve to obtain asphalt for sample preparation;

[0141] Step (202): Weigh 0.50g of the asphalt used to make the sample in step (201) above, accurate to 0.01g, put it into the mold sample cup, and flatten it;

[0142] Step (203): Insert the stopper rod into the mold sample cup, place it on a manual hydraulic press, pressurize it at a constant speed to 4MPa, stabilize the pressure for 10 minutes, and then release the pressure;

[0143] Step (204): Take out the asphalt sample after it has been pressed into sheets, place it in a vacuum drying oven at 90℃ and 0.09MPa for 1 hour, cool it for 30 minutes, weigh it, and record the mass of the asphalt sample (accurate to 0.0001g).

[0144] If the asphalt sample is broken or not compact after being pressed into a sheet, a drop of deionized water is added to the mold using a 1mL syringe with a needle during preparation. After the sample is loaded, another drop of deionized water is added to moisten it before pressing. The reason for adding water to moisten the mold and asphalt is that the dried asphalt is fragile during the pressing process, resulting in an incomplete sheet shape.

[0145] Comparative Example 1

[0146] Most wellbore plugs are mixtures of wax and bitumen, and the morphology of the plugs varies from well to well, making it impossible to prepare standardized samples. Figure 8 As shown, without extraction, the material is too soft to be extruded and molded, which affects the standardized analysis.

[0147] Comparative Example 2

[0148] Some blockages with high organic content can be molded, but the complex composition of these blockages, especially those with high wax content, causes the prepared samples to deform at slightly higher temperatures and solidify at room temperature, making quantitative analysis difficult. Figure 9 As shown, it is therefore essential to extract asphaltenes from blockages or from crude oil.

[0149] In summary, the method for preparing asphalt samples of the present invention standardizes the prepared asphalt samples by controlling the extraction of asphalt, the use of molds, and the pressing conditions. Furthermore, the method clarifies the operating conditions for pressing asphalt samples into sheets, thereby improving the accuracy of the experimental process and facilitating the study of the solubility, dispersion, and other properties of asphalt.

[0150] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing asphalt sample sections, characterized in that, Includes the following steps: Asphalt extraction; The extracted asphalt was pressed into sheets to obtain asphalt sample sheets; The asphaltenes extraction includes: Add the first solvent to the asphalt extract raw material, heat and reflux, let stand, filter, and obtain filter paper with insoluble matter; The first solvent was added to the filter paper containing insoluble matter and refluxed for extraction. After reflux, the second solvent was added and heated for reflux. The second solvent was then removed to obtain the extracted asphalt.

2. The method for preparing an asphalt sample as described in claim 1, characterized in that: The step of pressing the extracted asphalt into sheets to obtain asphalt sample sheets includes: placing the extracted asphalt inside a mold, applying pressure to the mold and stabilizing the pressure, replacing the bottom mold after stabilization, and extruding the sample sheet to obtain the asphalt sample sheet.

3. The method for preparing an asphalt sample as described in claim 2, characterized in that: Before applying pressure to the mold, drip water onto the mold and the bitumen.

4. The method for preparing an asphalt sample as described in claim 1, characterized in that: The process of adding a first solvent to the asphalt extract raw material, heating and refluxing, allowing it to stand, and filtering to obtain filter paper with insoluble matter includes: Add the first solvent to the asphalt extract and heat under reflux for 55-65 minutes. After the reflux is complete, let it stand for 90-150 minutes. Filter the solvent after standing to obtain filter paper with insoluble matter.

5. A method for preparing an asphalt sample as described in claim 1 or 4, characterized in that: The asphalt extraction raw materials include residual oil and blockage material, wherein the residual oil is obtained from crude oil.

6. The method for preparing an asphalt sample as described in claim 1, characterized in that: The process involves adding a first solvent to filter paper containing insoluble matter and performing reflux extraction. After reflux, a second solvent is added and the mixture is heated and refluxed to remove the second solvent, yielding the extracted asphaltene, comprising: Add the first solvent to the filter paper containing insoluble matter and perform reflux extraction; After reflux extraction, a second solvent is added and the mixture is heated under reflux. After heating to reflux is complete, the second solvent is removed by distillation. After the second solvent removal is completed, the extracted asphalt is obtained by drying.

7. The method for preparing an asphalt sample as described in claim 6, characterized in that: The reflux extraction time is ≥60 min, and the dripping rate of the first solvent during the reflux extraction process is controlled to be 2 drops / s-4 drops / s.

8. The method for preparing an asphalt sample as described in claim 6, characterized in that: The amount of the second solvent added is 50mL-100mL.

9. The method for preparing an asphalt sample as described in claim 6, characterized in that, The drying process includes maintaining a temperature of 100℃-110℃ and a negative pressure of 53.3kPa-66.7kPa for 40min-80min.

10. The method for preparing an asphalt sample as described in claim 1, characterized in that: The first solvent is n-heptane, and the second solvent is toluene.

11. The method for preparing an asphalt sample as described in claim 1, characterized in that: The pressure for pressing the sheet is 3MPa-5MPa.

12. An asphalt sample, characterized in that: It is prepared by the preparation method according to any one of claims 1-11.

13. The bituminous sample as described in claim 12, characterized in that, The specifications of the bituminous sample include: a diameter of 9.9mm-10.1mm, a thickness of 4mm-5mm, and a mass of 0.45g-0.55g.

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