A viscosity-reducing and oil displacement agent for heavy oil based on functionalized mesoporous materials and its preparation method

Abstract

This invention discloses a heavy oil viscosity-reducing and oil displacement agent based on functionalized mesoporous materials and its preparation method, belonging to the field of heavy oil extraction technology. The oil displacement agent of this invention comprises 1-5 parts of functionalized mesoporous material and 100 parts of a composite dispersant; the composite dispersant is composed of betaine, sulfonate, and water, wherein the total mass of betaine and sulfonate accounts for 60% of the mass of the composite dispersant, with a mass ratio of 1:(1-5). The functionalized mesoporous material of this invention is obtained from lignin through carbonization, oxidation, sulfonation, and alkyl glycoside grafting. This invention, through the synergistic effect of functionalized mesoporous materials and composite dispersants, can achieve efficient heavy oil viscosity reduction and oil washing, and has the advantages of being environmentally friendly and having a simple process, making it suitable for heavy oil extraction.

Description

Technical Field

[0001] This invention belongs to the field of heavy oil extraction technology, specifically relating to a heavy oil viscosity reducer and oil displacement agent based on functionalized mesoporous materials and its preparation method. Background Technology

[0002] As conventional oil reserves dwindle, heavy oil is gaining increasing importance and is becoming the primary focus of future oilfield development. my country possesses abundant heavy oil reserves; statistics show that, based on heavy oil standards, approximately 4 billion tons were proven in 2018, accounting for 30% of the country's total oil resources. Onshore reserves are mainly distributed in the Shengli Oilfield, Liaohe Oilfield, Xinjiang Oilfield, Nanyang Oilfield, Tahe Oilfield, and Tarim Oilfield, while offshore heavy oil resources are primarily located in the Bohai Bay region, with 62% of the 4.5 billion tons of proven oil reserves in the Bohai Sea being heavy oil. Due to the inherent characteristics of heavy oil, its extraction is difficult and costly.

[0003] The commonly used chemical viscosity reduction technology both domestically and internationally is emulsification viscosity reduction. This involves adding surfactants, such as nonylphenol polyoxyethylene ether surfactants, to heavy oil to transform high-viscosity crude oil from a W / O type to an O / W type emulsion, thus reducing the viscosity of heavy oil. However, these commonly used surfactants are not only difficult to degrade but also pose environmentally unfriendly problems such as severe formation pollution and well scaling. Furthermore, due to the large differences in the composition of heavy oil and the complex relationship between viscosity reducers and heavy oil, the emulsification viscosity reduction effect varies greatly, and some heavy oils are difficult to emulsify for viscosity reduction. On the other hand, traditional surfactants have strong adsorption capacity on rock surfaces, limited oil washing efficiency, and cannot effectively change the flow behavior of heavy oil in pores, making it difficult to wash away crude oil adhering to the formation rock surface, and the remaining heavy oil is difficult to displace, resulting in very limited heavy oil recovery. Therefore, there is an urgent need in this field for a novel heavy oil viscosity reduction and oil displacement system that can efficiently reduce viscosity, deeply strip heavy oil from the rock surface, and also possess good dispersibility and environmental friendliness. Summary of the Invention

[0004] This invention addresses the core problem of poor fluidity caused by the high viscosity of heavy oil, which is a completely different technical problem from the large seepage resistance caused by the small pore throat in low-permeability tight reservoirs.

[0005] In view of this, the purpose of this invention is to provide a heavy oil viscosity-reducing and oil displacement agent based on functionalized mesoporous materials and its preparation method. This invention first prepares functionalized mesoporous materials and then combines them with a composite dispersant to obtain a heavy oil viscosity-reducing and oil displacement agent based on functionalized mesoporous materials. This agent retains the extremely high specific surface area and porous structure characteristics of the mesoporous materials, providing a larger contact area with heavy oil molecules and improving oil washing efficiency. Simultaneously, by functionalizing and modifying the mesoporous materials, their dispersing performance is improved, overcoming the problems of traditional emulsification viscosity reduction methods and achieving effective reduction of heavy oil viscosity and a significant increase in oil recovery.

[0006] The present invention is specifically implemented using the following technical solutions: A viscosity-reducing and oil displacement agent for heavy oil based on functionalized mesoporous materials, comprising the following raw materials in parts by weight: Functionalized mesoporous material, 1 to 5 parts; 100 parts of composite dispersant; The composite dispersant is composed of betaine, sulfonate and water, wherein the total mass of betaine and sulfonate accounts for 60% of the mass of the composite dispersant, and the mass ratio of betaine to sulfonate is 1:(1~5). The preparation method of the functionalized mesoporous material includes the following steps: (1) Mix lignin with concentrated sulfuric acid with a mass concentration of 70% to 90% at a ratio of 1 g: 10 mL, stir at 20 to 30 °C for 20 to 40 min, and then filter; wash the filter cake with distilled water until the washing liquid is neutral; dry the washed solid at 80 to 120 °C for 6 to 12 h; then calcine and carbonize the dried material at 950 to 1050 °C for 1.5 to 2.5 h under an argon atmosphere to obtain a black powder; mix the obtained black powder with distilled water at a mass ratio of 1:100, heat under reflux for 8 to 12 h, cool and filter, wash with distilled water 2 to 3 times, and finally dry to obtain an active mesoporous material.

[0007] (2) Take 1 g of the active mesoporous material obtained in step (1), place it in an ice-water bath at 0℃, and then add 80-120 mL of concentrated sulfuric acid with a mass concentration of 98%, and stir to mix evenly; under continuous stirring and cooling in an ice-water bath, slowly add 1-3 g of potassium permanganate in batches, controlling the addition process to last for 1-1.5 h to prevent the temperature from exceeding 5℃; after the addition is completed, transfer the reaction system to a water bath at 40-50℃ and continue the reaction for 1-3 h to complete the oxidation reaction; then, add 3-5 g of sodium amino ether sulfonate to the system, and adjust the pH of the system to 9-10 with a 30% NaOH aqueous solution; stir the reaction system at 60-90℃ for 8-10 h to carry out the sulfonation reaction, and obtain a sulfonated mesoporous material suspension; then, add 2-5 g of alkyl glycoside to the suspension, and continue stirring the reaction at 50-80℃ for 12-15 h. h, complete the grafting reaction; after the reaction is complete, cool the reaction system to room temperature, collect the solid product by centrifugation, and wash it repeatedly with distilled water by centrifugation 3 to 5 times until the supernatant is neutral; place the obtained solid filter cake in a vacuum drying oven at 50 to 80°C for 6 to 8 hours to dry, and grind it to obtain the functionalized mesoporous material.

[0008] The preparation method of the functionalized mesoporous material can be carried out in a scaled-up manner. After the product is combined, dried and ground, a specified mass can be weighed as needed for subsequent steps without affecting its structural and performance characteristics or the final application performance.

[0009] Preferably, the betaine is one or a mixture of cocamidopropyl betaine and lauramidopropyl betaine.

[0010] Preferably, the sulfonate is a fatty acid methyl ester sulfonate.

[0011] The present invention discloses a method for preparing a heavy oil viscosity reducing and displacement agent based on functionalized mesoporous materials, which involves mixing the functionalized mesoporous materials and the composite dispersant at 20-30°C and a stirring speed of 300-800 rpm for 10-30 minutes until the mixture is uniform.

[0012] Compared with the prior art, the present invention has the following effects: (1) This invention uses economical, environmentally friendly and abundant biomass lignin as raw material to prepare functionalized mesoporous materials. The prepared functionalized mesoporous materials have extremely high specific surface area and rich porous structure, which can effectively adsorb the gum asphaltenes in heavy oil. At the same time, the alkyl glycosides grafted on its surface have a synergistic effect with betaine and sulfonate in the composite dispersant, thereby achieving a high viscosity reduction rate of ≥96%.

[0013] (2) The functionalized mesoporous material of the present invention, as a solid nanoparticle, can adsorb and replace heavy oil molecules on the rock surface, significantly improving the stripping efficiency of heavy oil on the rock surface (oil washing rate ≥80%).

[0014] (3) The raw materials such as betaine, sulfonate and alkyl glycoside selected in this invention have excellent biodegradability, and the organic chlorine content in the product is 0, which avoids the problems of formation pollution and oil well scaling.

[0015] (4) The functionalized mesoporous material of the present invention has a simple composition of heavy oil viscosity reducing and oil displacement agent, and the final preparation step is only physical mixing. The process is reasonable and suitable for large-scale production.

[0016] As shown in Examples 4 to 7, the viscosity reduction rate of the functionalized mesoporous materials of the present invention for heavy oil viscosity reducing and displacement agents is ≥96%, and the oil washing rate is ≥84.8%, which is significantly better than that of the comparative examples. This is due to the efficient adsorption of asphaltenes by the functionalized mesoporous materials and their synergistic effect with the composite dispersant.

[0017] Furthermore, the heavy oil viscosity reducer and displacement agent based on functionalized mesoporous materials of the present invention does not affect the performance of other crude oil dehydrating agents and will not cause pollution to crude oil separation and water. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the preferred embodiments of this invention will be described in further detail below with reference to the examples. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0019] The alkyl glycosides used in the following embodiments of the present invention were purchased from Shandong Yousuo Chemical Technology Co., Ltd., model APG1214, with a content of 50%; fatty acid methyl ester sulfonate was purchased from Shandong Yousuo Chemical Technology Co., Ltd., model label: FMES, with a content ≥70%; sodium amino polyether sulfonate was purchased from Beijing Baiyuan Chemical Co., Ltd., with a content of 90%, a molar mass of approximately 550 g / mol, and the structural formula is:

[0020] The cocamidopropyl betaine used in this invention was purchased from Zhejiang Rujie Chemical Co., Ltd., product model CAB, with a content of approximately 45%; lauramide propyl betaine was purchased from Zhejiang Rujie Chemical Co., Ltd., product model LAB, with a content of approximately 40%.

[0021] The functionalized mesoporous material described in this embodiment of the invention is prepared using the following method: (1) Mix lignin with concentrated sulfuric acid with a mass concentration of 70% to 90% at a ratio of 1 g: 10 mL, stir at 20 to 30 °C for 20 to 40 min, and then filter; wash the filter cake with distilled water until the washing liquid is neutral; dry the washed solid at 80 to 120 °C for 6 to 12 h; then calcine the dried material at 950 to 1050 °C for 1.5 to 2.5 h under an argon atmosphere to obtain a black powder; mix the obtained black powder with distilled water at a mass ratio of 1:100, heat under reflux for 8 to 12 h, cool and filter, wash with distilled water 2 to 3 times, and finally dry to obtain an active mesoporous material; (2) Take 1 g of the active mesoporous material obtained in step (1), place it in an ice-water bath at 0℃, and then add 80-120 mL of concentrated sulfuric acid with a mass concentration of 98%, and stir to mix evenly; under continuous stirring and cooling in an ice-water bath, slowly add 1-3 g of potassium permanganate in batches, controlling the addition process to last for 1-1.5 h to prevent the temperature from exceeding 5℃; after the addition is completed, transfer the reaction system to a water bath at 40-50℃ and continue the reaction for 1-3 h to complete the oxidation reaction; then, add 3-5 g of sodium amino ether sulfonate to the system, and adjust the pH of the system to 9-10 with a 30% NaOH aqueous solution; stir the reaction system at 60-90℃ for 8-10 h to carry out the sulfonation reaction, and obtain a sulfonated mesoporous material suspension; then, add 2-5 g of alkyl glycoside to the suspension, and continue stirring the reaction at 50-80℃ for 12-15 h. h, complete the grafting reaction; after the reaction is complete, cool the reaction system to room temperature, collect the solid product by centrifugation, and wash it repeatedly with distilled water by centrifugation 3 to 5 times until the supernatant is neutral; place the obtained solid filter cake in a vacuum drying oven at 50 to 80°C for 6 to 8 hours to dry, and grind it to obtain the functionalized mesoporous material.

[0022] The preparation method of the functionalized mesoporous material can be carried out in a scaled-up manner. After the product is combined, dried and ground, a specified mass can be weighed as needed for subsequent steps without affecting its structural and performance characteristics or the final application performance.

[0023] According to the BET method test, the specific surface area of ​​the functionalized mesoporous materials obtained in Examples 1 to 3 of this invention is all above 2000 m². 2 The average pore size is 2.56 nm and the weight is above 1 g.

[0024] Example 1 (1) Mix lignin with 80% concentrated sulfuric acid at a ratio of 1 g: 10 mL, stir at 25°C for 30 min, and then filter; wash the filter cake with distilled water until the washing liquid is neutral; dry the washed solid at 105°C for 8 h; then calcine the dried material at 1000°C for 2 h under an argon atmosphere to obtain a black powder; mix the obtained black powder with distilled water at a mass ratio of 1:100, heat under reflux for 10 h, cool and filter, wash with distilled water 3 times, and finally dry to obtain the active mesoporous material; (2) Take 1 g of the active mesoporous material obtained in step (1), place it in an ice-water bath at 0℃, and then add 100 mL of concentrated sulfuric acid with a mass concentration of 98%, and stir to mix evenly; under continuous stirring and cooling in the ice-water bath, slowly add 2 g of potassium permanganate in batches, controlling the addition process to last for 1 h to prevent the temperature from exceeding 5℃; after the addition is completed, transfer the reaction system to a water bath at 45℃ and continue the reaction for 2 h to complete the oxidation reaction; then, add 4 g of sodium amine polyether sulfonate to the system, and adjust the pH value of the system to 9 ~ 10 with a NaOH aqueous solution with a mass concentration of 30%; stir the reaction system at 80℃ for 9 h to carry out the sulfonation reaction and obtain a sulfonated mesoporous material suspension; then, add 3.5 g of alkyl glycoside to the suspension, and continue stirring the reaction at 65℃ for 13 h. h, complete the grafting reaction; after the reaction is completed, cool the reaction system to room temperature, collect the solid product by centrifugation, and wash it repeatedly with distilled water by centrifugation 3 times until the supernatant is neutral; place the obtained solid filter cake in a vacuum drying oven at 80℃ for 6 h, grind it to obtain the functionalized mesoporous material.

[0025] Example 2 (1) Mix lignin with 90% concentrated sulfuric acid at a ratio of 1 g: 10 mL, stir at 20°C for 40 min, and then filter; wash the filter cake with distilled water until the washing liquid is neutral; dry the washed solid at 120°C for 6 h; then calcine the dried material at 950°C for 2.5 h under an argon atmosphere to obtain a black powder; mix the obtained black powder with distilled water at a mass ratio of 1:100, heat under reflux for 12 h, cool and filter, wash with distilled water 3 times, and finally dry to obtain an active mesoporous material; (2) Take 1 g of the active mesoporous material obtained in step (1), place it in an ice-water bath at 0℃, and then add 120 mL of concentrated sulfuric acid with a mass concentration of 98%, and stir to mix evenly; under continuous stirring and cooling in the ice-water bath, slowly add 1 g of potassium permanganate in batches, controlling the addition process to last for 1 h to prevent the temperature from exceeding 5℃; after the addition is completed, transfer the reaction system to a water bath at 50℃ and continue the reaction for 1 h to complete the oxidation reaction; then, add 3 g of sodium amine polyether sulfonate to the system, and adjust the pH value of the system to 9 ~ 10 with a NaOH aqueous solution with a mass concentration of 30%; stir the reaction system at 90℃ for 8 h to carry out the sulfonation reaction and obtain a sulfonated mesoporous material suspension; then, add 2 g of alkyl glycoside to the suspension, and continue stirring the reaction at 50℃ for 15 h. h, complete the grafting reaction; after the reaction is completed, cool the reaction system to room temperature, collect the solid product by centrifugation, and wash it repeatedly with distilled water by centrifugation 3 times until the supernatant is neutral; place the obtained solid filter cake in a vacuum drying oven at 60℃ for 8 h, grind it to obtain the functionalized mesoporous material.

[0026] Example 3 (1) Mix lignin with 70% concentrated sulfuric acid at a ratio of 1 g: 10 mL, stir at 30°C for 20 min, and then filter; wash the filter cake with distilled water until the washing liquid is neutral; dry the washed solid at 80°C for 12 h; then calcine the dried material at 1050°C for 1.5 h under an argon atmosphere to obtain a black powder; mix the obtained black powder with distilled water at a mass ratio of 1:100, heat under reflux for 8 h, cool and filter, wash with distilled water 3 times, and finally dry to obtain an active mesoporous material; (2) Take 1 g of the active mesoporous material obtained in step (1), place it in an ice-water bath at 0℃, and then add 80 mL of concentrated sulfuric acid with a mass concentration of 98%, and stir to mix evenly; under continuous stirring and cooling in the ice-water bath, slowly add 3 g of potassium permanganate in batches, controlling the addition process to last for 1.5 h to prevent the temperature from exceeding 5℃; after the addition is completed, transfer the reaction system to a water bath at 40℃ and continue the reaction for 3 h to complete the oxidation reaction; then, add 5 g of sodium amino ether sulfonate to the system, and adjust the pH value of the system to 9 ~ 10 with a NaOH aqueous solution with a mass concentration of 30%; stir the reaction system at 60℃ for 10 h to carry out the sulfonation reaction and obtain a sulfonated mesoporous material suspension; then, add 5 g of alkyl glycoside to the suspension and continue stirring at 80℃ for 12 h. h, complete the grafting reaction; after the reaction is completed, cool the reaction system to room temperature, collect the solid product by centrifugation, and wash it repeatedly with distilled water by centrifugation 3 times until the supernatant is neutral; place the obtained solid filter cake in a vacuum drying oven at 70℃ for 7 h to dry, and grind it to obtain the functionalized mesoporous material.

[0027] Example 4 A viscosity reducer and oil displacement agent for heavy oil based on functionalized mesoporous materials, comprising a mixture of the following raw materials: Functionalized mesoporous materials: 1 g Composite dispersant: 100 g The composite dispersant consists of the following components: 5 g of cocamidopropyl betaine, 5 g of lauramide propyl betaine, 50 g of fatty acid methyl ester sulfonate, and 40 g of distilled water. The functionalized mesoporous material was prepared using Example 1.

[0028] The preparation method of the heavy oil viscosity reducing and displacement agent is as follows: 1 g of functionalized mesoporous material and 100 g of the above-mentioned composite dispersant are mixed at 25°C and stirred at 500 rpm for 20 min until uniformly dispersed, thus obtaining the heavy oil viscosity reducing and displacement agent based on functionalized mesoporous material.

[0029] Example 5 A viscosity reducer and oil displacement agent for heavy oil based on functionalized mesoporous materials, comprising a mixture of the following raw materials: Functionalized mesoporous materials: 3 g Composite dispersant: 100 g The composite dispersant consists of the following components: 10 g of cocamidopropyl betaine, 50 g of fatty acid methyl ester sulfonate, and 40 g of distilled water. The functionalized mesoporous material was prepared using Example 2.

[0030] The preparation method of the heavy oil viscosity reducer and oil displacement agent is the same as in Example 4.

[0031] Example 6 A viscosity reducer and oil displacement agent for heavy oil based on functionalized mesoporous materials, comprising a mixture of the following raw materials: Functionalized mesoporous material: 5 g Composite dispersant: 100 g The composite dispersant consists of the following components: 10 g lauramidopropyl betaine, 50 g fatty acid methyl ester sulfonate, and 40 g distilled water. The functionalized mesoporous material was prepared using Example 3.

[0032] The preparation method of the heavy oil viscosity reducer and oil displacement agent is the same as in Example 4.

[0033] Example 7 A viscosity reducer and oil displacement agent for heavy oil based on functionalized mesoporous materials, comprising a mixture of the following raw materials: Functionalized mesoporous materials: 1 g Composite dispersant: 100 g The composite dispersant consists of the following components: 15 g of cocamidopropyl betaine, 15 g of lauramide propyl betaine, 30 g of fatty acid methyl ester sulfonate, and 40 g of distilled water. The functionalized mesoporous material was prepared using Example 1.

[0034] The preparation method of the heavy oil viscosity reducer and oil displacement agent is the same as in Example 4.

[0035] Comparative Example 1 This comparative example uses a conventional emulsifying viscosity reducer. 60 g of nonylphenol polyoxyethylene ether (OP-10) was mixed with 40 g of distilled water.

[0036] Comparative Example 2 This comparative example uses only 100 g of the same composite dispersant as in Example 4 (i.e., without any functionalized mesoporous material).

[0037] Comparative Example 3 In this comparative example, 1 g of functionalized mesoporous material in Example 1 was replaced with 1 g of ordinary commercially available activated carbon without any chemical modification, and the rest of the preparation conditions were exactly the same as in Example 4.

[0038] Comparative Example 4 In this comparative example, the functionalized mesoporous material in Example 4 is replaced with the active mesoporous material obtained by only completing (1) of the preparation method of functionalized mesoporous material, without (2) oxidation, sulfonation and grafting modification, and the other preparation conditions are exactly the same as those in Example 1.

[0039] Performance testing and results analysis: The samples prepared in Examples 4-7 and Comparative Examples 1-4 of this invention were diluted to a 0.3% aqueous solution for performance testing. The test oil sample was selected from a heavy oil block in the Shengli Oilfield. The viscosity of the heavy oil at the surface was 10250 mPa·s at a reservoir temperature of 50℃. The test method is as follows: The viscosity reduction rate, natural sedimentation dehydration rate, and oil washing rate were tested according to the enterprise standard Q / SH1020 2871-2021 "General Technical Conditions for Heavy Oil Viscosity Reducing and Displacement Agents" of China Petrochemical Corporation Shengli Petroleum Administration Co., Ltd. The interfacial tension between the solution and heavy oil was measured using a TX-500 rotating drop interfacial tensiometer.

[0040] Table 1

[0041] Based on the above experimental results, the following conclusions can be drawn: (1) The performance indicators of Examples 4 to 7 of the present invention are significantly better than those of Comparative Example 1 (traditional OP-10 viscosity reducer). Especially in terms of the two key indicators of washing efficiency and viscosity reduction rate, this proves the technological revolution of the functionalized mesoporous material + composite dispersant system compared with single emulsification viscosity reduction.

[0042] (2) The performance of Comparative Example 2 (without mesoporous material) is far inferior to that of the Example. This proves that the technical effect of the present invention cannot be achieved by the composite dispersant alone. The introduction of functionalized mesoporous material is not a simple superposition, but rather produces a synergistic effect with the dispersant: the functionalized mesoporous material, with its extremely high specific surface area, is responsible for adsorbing and stripping heavy oil from the rock surface, while the composite dispersant is responsible for viscosity reduction and dispersion. Both are indispensable, thus proving the synergistic effect of the heavy oil viscosity-reducing and oil displacement agent formulation of the present invention.

[0043] (3) Although the performance of Comparative Example 3 (ordinary activated carbon) is slightly better than that of Comparative Example 2, it is still far inferior to the embodiments of the present invention. This shows that not all materials can achieve the effects of the present invention. Only materials prepared by the present invention, with extremely high specific surface area (>2000 m²), can achieve the desired results. 2 Only functionalized mesoporous materials with specific surface chemistry properties ( / g) can produce the best synergistic effect with composite dispersants.

[0044] (4) The performance indicators of Comparative Example 4 (unfunctionalized active mesoporous material) are all at the same low level as Comparative Example 3 (ordinary activated carbon), far lower than those of the embodiments of the present invention. This shows that simply obtaining a mesoporous structure with a high specific surface area through carbonization is far from sufficient. Furthermore, the extremely high specific surface area and abundant porous structure of the functionalized mesoporous material prepared in this invention, combined with the alkyl glycosides grafted onto its surface and the betaine and sulfonates in the composite dispersant, are necessary to effectively adsorb the asphaltenes in heavy oil, thereby achieving high viscosity reduction and high oil washing efficiency.

[0045] As can be seen from Table 1, the functionalized mesoporous material of this invention, used as a viscosity reducer and oil displacement agent for heavy oil, exhibits a natural sedimentation dehydration rate of over 85%. This high sedimentation rate means rapid oil-water separation and the absence of a stable emulsion layer, thus avoiding impact on subsequent dehydration processes and minimizing the burden on produced water treatment.

[0046] To verify the fundamental improvement of the water dispersibility of mesoporous materials by functionalization modification, a static sedimentation experiment was conducted. The samples prepared in Example 4, Comparative Example 3 (ordinary activated carbon), and Comparative Example 4 (unfunctionalized activated mesoporous material) of this invention were placed in colorimetric tubes and observed at room temperature.

[0047] Experimental phenomena: The sample of Comparative Example 3 completely settled within 30 minutes after standing, with all the activated carbon powder deposited at the bottom of the tube, and the upper liquid becoming clear. The sample of Comparative Example 4 also completely settled after 30 minutes, exhibiting the same behavior as Comparative Example 3. In stark contrast, the sample of Example 1 of this invention remained homogeneous even after standing for 24 hours, without any stratification or precipitation.

[0048] Experimental Conclusion: This demonstrates that simple carbonization activation and increased specific surface area do not necessarily impart good water dispersibility to the material. Subsequent functionalization modification, introducing strongly hydrophilic groups such as sulfonic acid groups and alkyl glycosides (APGs) onto the surface of mesoporous materials, transforms them from hydrophobic materials into functionalized materials with excellent hydrophilicity and interfacial stability, thereby significantly improving water dispersibility. Comparative Example 4 and Example 4 provide a stark contrast, both demonstrating the indispensability of the functionalized mesoporous material preparation process. This fundamental transformation solves the technical bottleneck of easy aggregation and sedimentation of nanomaterials in oil displacement agent systems, laying a solid foundation for ensuring product stability and application effectiveness.

[0049] In summary, the entire scope of protection claimed in the claims of this invention (including the amount of functionalized mesoporous material and the ratio of composite dispersant) has been fully supported by the embodiments, solving the problems of low oil washing efficiency, single function, and environmental unfriendliness of traditional technologies. Moreover, it has produced unexpected technical effects compared with the prior art, possessing outstanding substantive features and significant progress, and meets the requirements of the Patent Law regarding inventiveness.

[0050] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A viscosity-reducing and oil displacement agent for heavy oil based on functionalized mesoporous materials, characterized in that, The raw materials include the following parts by weight: Functionalized mesoporous material, 1 to 5 parts; 100 parts of composite dispersant; The composite dispersant is composed of betaine, sulfonate and water, wherein the total mass of betaine and sulfonate accounts for 60% of the mass of the composite dispersant, and the mass ratio of betaine to sulfonate is 1:(1~5). The preparation method of the functionalized mesoporous material includes the following steps: (1) Mix lignin with concentrated sulfuric acid with a mass concentration of 70% to 90% at a ratio of 1 g: 10 mL, stir at 20 to 30 °C for 20 to 40 min, and then filter; wash the filter cake with distilled water until the washing liquid is neutral; dry the washed solid at 80 to 120 °C for 6 to 12 h; then calcine the dried material at 950 to 1050 °C for 1.5 to 2.5 h under an argon atmosphere to obtain a black powder; mix the obtained black powder with distilled water at a mass ratio of 1:100, heat under reflux for 8 to 12 h, cool and filter, wash with distilled water 2 to 3 times, and finally dry to obtain an active mesoporous material; (2) Take 1 g of the active mesoporous material obtained in step (1), place it in an ice-water bath at 0℃, and then add 80-120 mL of concentrated sulfuric acid with a mass concentration of 98%, and stir to mix evenly; under continuous stirring and cooling in an ice-water bath, slowly add 1-3 g of potassium permanganate in batches, controlling the addition process to last for 1-1.5 h to prevent the temperature from exceeding 5℃; after the addition is completed, transfer the reaction system to a water bath at 40-50℃ and continue the reaction for 1-3 h to complete the oxidation reaction; then, add 3-5 g of sodium amine polyether sulfonate to the system, and adjust the pH of the system to 9-10 with a 30% NaOH aqueous solution; stir the reaction system at 60-90℃ for 8-10 h to carry out the sulfonation reaction, and obtain a sulfonated mesoporous material suspension; then, add 2-5 g of alkyl glycoside to the suspension, and continue stirring the reaction at 50-80℃ for 12-15 h. h, complete the grafting reaction; after the reaction is complete, cool the reaction system to room temperature, collect the solid product by centrifugation, and wash it repeatedly with distilled water by centrifugation 3 to 5 times until the supernatant is neutral; place the obtained solid filter cake in a vacuum drying oven at 50 to 80°C for 6 to 8 hours to dry, and grind it to obtain the functionalized mesoporous material.

2. The heavy oil viscosity reducer and oil displacement agent based on functionalized mesoporous materials as described in claim 1, characterized in that, The betaine is one or a mixture of cocamidopropyl betaine and lauramidopropyl betaine.

3. The heavy oil viscosity reducer and oil displacement agent based on functionalized mesoporous materials as described in claim 1, characterized in that, The sulfonate is a fatty acid methyl ester sulfonate.

4. A method for preparing a heavy oil viscosity reducer and displacement agent based on functionalized mesoporous materials as described in any one of claims 1 to 3, characterized in that, The functionalized mesoporous material and the composite dispersant are mixed at 20-30°C and a stirring speed of 300-800 rpm for 10-30 minutes until they are uniformly mixed.

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