A sugar-based carbon quantum dot oil displacement agent for unconventional reservoirs, a preparation method and application thereof

Abstract

This invention discloses a glycosyl carbon quantum dot oil displacement agent for unconventional oil reservoirs, its preparation method, and its application, belonging to the field of oilfield chemical technology. The preparation of the glycosyl carbon quantum dot oil displacement agent for unconventional oil reservoirs of this invention includes: adding a carbon source and a modifier to an alcohol solution, stirring to dissolve, and then carrying out a hydrothermal reaction to obtain the product; wherein the modifier is a ketoxime modifier; this method is simple, low-cost, has controllable particle size, and high yield, making it suitable for industrial application; the obtained carbon quantum dots have a high specific surface area and functional groups such as carboxyl and hydroxyl groups, which can penetrate nanopores and synergistically reduce the oil-water interfacial tension to below 5.0 mN / m; this product has outstanding high-temperature resistance and penetration ability, and can effectively penetrate into the nanopore throat structure of tight reservoirs, significantly improving oil displacement efficiency through interfacial modification, and is particularly suitable for the exploitation of unconventional nano-oil and gas resources.

Description

Technical Field

[0001] This invention relates to a sugar-based carbon quantum dot flooding agent for unconventional oil reservoirs, its preparation method, and its application, belonging to the field of oilfield chemical technology. Background Technology

[0002] As a core strategic resource in the energy system, oil occupies a crucial position in the energy structure. With the continuous rise in global energy demand, the development of unconventional oil and gas resources is becoming increasingly important. However, the reservoirs of these resources typically have complex pore structures and low permeability, making them difficult to effectively address with traditional oil displacement agents, thus hindering further improvements in extraction efficiency. Currently, for most oilfields that have entered the late stages of development, traditional oil extraction technologies face problems such as low recovery rates and large amounts of crude oil remaining underground, especially in the high water-cut extraction stage, where the extraction difficulty increases significantly. Faced with these challenges, there is an urgent need for innovative technologies to improve extraction efficiency, break through existing technological bottlenecks, and ensure the stability and security of energy supply.

[0003] Tertiary oil recovery technology has become a research hotspot in the field of oil and gas extraction. However, traditional technologies such as waterflooding, gasflooding, foam flooding, polymer flooding, and surfactant flooding have significant limitations when facing complex geological conditions such as strong reservoir heterogeneity, low permeability, and high crude oil viscosity. For example, waterflooding efficiency drops sharply in the high water-cut stage, while polymer flooding and surfactant flooding face problems such as high cost and poor temperature resistance.

[0004] Nanomaterials and nanotechnology, with their unique physicochemical properties, are gradually becoming an emerging direction for oil and gas field development. The nanoscale size, high specific surface area, and good interfacial activity of nanomaterials help them penetrate deep into the micropores of reservoirs, improving oil displacement efficiency. However, most nanomaterials lack stability in high-temperature reservoir environments, limiting their large-scale application. For example, nano-silica particles are prone to silanol condensation reactions under high temperature and pressure, forming aggregates that block oil layer pores; nano-metal oxide particles undergo crystal transformation at high temperatures, altering surface properties and failing to effectively reduce oil-water interfacial tension.

[0005] Carbon quantum dots, typically smaller than 10 nm, are nanomaterials with high specific surface area and good chemical stability. They are often prepared using small-molecule organic acids and amine compounds, and their surfaces are easily functionalized. However, carbon quantum dots obtained by this method are highly hydrophilic but lack sufficient hydrophobicity, and the range of hydrophilicity / hydrophobicity adjustment is relatively limited. Although their interfacial activity can be improved through chemical grafting, this process is cumbersome and significantly increases the preparation cost. Therefore, developing a carbon quantum dot-based oil displacement agent that is easy to synthesize and has excellent interfacial activity is of great practical significance for the efficient development of unconventional oil and gas resources and for ensuring energy security. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a sugar-based carbon quantum dot displacement agent for unconventional oil reservoirs, its preparation method, and its application. This displacement agent utilizes its small size (1-10 nm) and interfacial activity to penetrate deep into the micro-nano pores of unconventional oil reservoirs, significantly altering the interfacial properties at the solid / liquid (rock / crude oil) and oil / water interfaces, making it easier for crude oil to be displaced. This solves the problems of insufficient chemical stability and interfacial activity of existing displacement agents in unconventional oil reservoirs, and the difficulty in penetrating deep into rock pores to change surface wettability, thus promoting the advancement of unconventional oil reservoir exploitation technology.

[0007] To achieve the above objectives, the following technical solution is provided: The first objective of this invention is to provide a method for preparing a sugar-based carbon quantum dot flooding agent for unconventional oil reservoirs. The method includes the following steps: adding a carbon source and a modifier to an alcohol solution, stirring to dissolve, and then carrying out a hydrothermal reaction to obtain the agent.

[0008] In one embodiment, the carbon source includes sugars or derivatives thereof.

[0009] In one embodiment, the carbon source includes at least one of glucose, sucrose, xylitol, vitamin C, and N-acetyl-D-glucosamine.

[0010] In one embodiment, the alcohol solution includes at least one selected from ethanol, propanol, ethylene glycol, propylene glycol, and glycerol solution; preferably ethanol and / or glycerol solution.

[0011] In one embodiment, the modifier includes at least one selected from cyclohexanone oxime, cyclopentanone oxime, cycloheptanone oxime, and methylcyclohexanone oxime.

[0012] In one embodiment, the mass ratio of the carbon source, modifier, and alcohol is 1~20:5~10:100; preferably 3~15:3~8:100.

[0013] In one embodiment, the concentration of the alcohol solution is 40 wt.% to 60 wt.%; preferably 45 wt.% to 55 wt.%; more preferably 50 wt.%.

[0014] In one embodiment, the hydrothermal reaction is carried out at a temperature of 180-200°C for 4-8 hours.

[0015] In one embodiment, the reaction is followed by centrifugation, filtration, dialysis, and drying steps to obtain a glycosyl carbon quantum dot flooding agent for unconventional reservoirs.

[0016] In one embodiment, the drying is performed by freeze drying or heat drying; when heat drying is used, the drying temperature does not exceed 70°C.

[0017] In one embodiment, the filtration is performed using an ultrafiltration membrane with a pore size of 0.22 micrometers for purification.

[0018] A second objective of this invention is to provide a glycosyl carbon quantum dot flooding agent for unconventional oil reservoirs prepared by the method described above.

[0019] In one embodiment, the glycosyl carbon quantum dot oil displacement agent has a particle size of 1.0~10.0 nm.

[0020] In one embodiment, the glycosyl carbon quantum dot oil displacement agent further includes a base liquid.

[0021] In one embodiment, the base liquid includes one or more of deionized water, brine, polymer solution, surfactant solution, and organic solvent.

[0022] The third objective of this invention is to provide an application of the aforementioned sugar-based carbon quantum dot flooding agent for unconventional reservoirs in oil and gas extraction.

[0023] In one embodiment, the oil and gas extraction is the extraction of unconventional oil reservoirs.

[0024] In one embodiment, the concentration of the glycosyl carbon quantum dot oil displacement agent is 0.3 wt.% to 3.0 wt.%.

[0025] The fourth objective of this invention is to provide a method for improving the extraction efficiency of unconventional oil reservoirs, wherein the method employs the aforementioned sugar-based carbon quantum dot oil displacement agent for unconventional oil reservoirs.

[0026] The fifth objective of this invention is to provide a method for exploiting oil reservoirs in high-temperature and complex environments, wherein the method employs the aforementioned unconventional reservoir oil displacement agent based on glycosyl carbon quantum dots.

[0027] Beneficial effects: (1) This invention uses sugars as carbon source to form carbon quantum dots through dehydration condensation polymerization reaction, and uses ketoxime modifiers to improve the interfacial activity of carbon quantum dots; compared with carbon quantum dots synthesized by adding amine compounds, it can improve the salt resistance of the product; the preparation method has a simple process flow, mild reaction conditions, low raw material price, controllable carbon quantum dot particle size and high yield, and is suitable for industrial production. (2) The glycosyl carbon quantum dots provided by this invention have a particle size of less than 10 nanometers, high activity and high specific surface area, and can effectively penetrate nanometer to micrometer-scale pores. By reducing the oil-water interfacial tension to below 5.0 mN / m and regulating the rock surface to an ultra-water-wet state, efficient oil displacement is achieved through a multi-effect synergistic mechanism; in addition, the quantum dots exhibit excellent temperature resistance and can withstand conditions up to 220℃ and above, making them suitable for high-temperature complex reservoir environments; (3) The glycosyl carbon quantum dot oil displacement agent provided by this invention can be elemental glycosyl carbon quantum dots or a mixture thereof with a base liquid, with a particle size controlled at 1.0-10.0 nm. The particle size of these quantum dots is adapted to the nanopore throat, exhibiting excellent injection and flowability, making them particularly suitable for the development of tight nano-oil and gas reservoirs; they can be used directly for in-situ extraction or compounded with base liquids to enhance the oil displacement effect. Their abundant oxime, hydroxyl, and other functional groups significantly improve oil displacement performance. In addition, glycosyl carbon quantum dots possess excellent mechanical, chemical, and thermal stability, and can withstand high-temperature and high-salt environments; their low toxicity and high biocompatibility characteristics better meet the needs of green oil and gas development. Attached Figure Description

[0028] Figure 1 This is a transmission electron microscope image of the glycosyl carbon quantum dots in Example 1; Figure 2 This is a schematic diagram of the particle size distribution of glycosyl carbon quantum dots in Example 1; Figure 3 The infrared spectrum analysis of the glycosyl carbon quantum dots in Example 1; Figure 4 Thermogravimetric analysis (TGA) curves of the glycosyl carbon quantum dots in Example 1; Figure 5 This is a graph showing the effect of glycosyl carbon quantum dots on the surface tension of deionized water in Example 1. Figure 6 This is a graph showing the effect of glycosyl carbon quantum dots on the interfacial tension of n-decane / water in Example 1; Figure 7 This is a graph showing the change in the wetting angle of the glass surface before and after treatment with glycosyl carbon quantum dots in Example 1. Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments and accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0030] Example 1 A method for preparing glycosyl carbon quantum dots includes the following: 5g of sucrose and 2g of cyclohexanone oxime were added to 100g of a 50wt.% ethanol solution and stirred until completely dissolved and evenly dispersed. The mixture was placed in a polytetrafluoroethylene-lined hydrothermal reactor and reacted at 180℃ for 4 hours. After the reaction, the mixture was centrifuged, filtered through a 0.22-micron pore size filter, dialyzed through a 1000 molecular weight cutoff dialysis bag for 48 hours, and finally freeze-dried to obtain glycosyl carbon quantum dots.

[0031] Example 2 A method for preparing glycosyl carbon quantum dots includes the following: 5g of glucose and 2g of cyclopentanone oxime were added to 100g of 50wt.% ethanol solution and stirred until completely dissolved and evenly dispersed. The mixture was placed in a polytetrafluoroethylene-lined hydrothermal reactor and reacted at 180℃ for 8 hours. After the reaction, the mixture was centrifuged, filtered through a 0.22-micron pore size filter, dialyzed through a 1000 molecular weight cutoff dialysis bag for 48 hours, and finally freeze-dried to obtain glycosyl carbon quantum dots.

[0032] Example 3 A method for preparing glycosyl carbon quantum dots includes the following: 5g of N-acetyl-D-glucosamine and 2g of cycloheptanone oxime were added to 100g of a 50wt.% ethanol solution and stirred until completely dissolved and evenly dispersed. The mixture was placed in a polytetrafluoroethylene-lined hydrothermal reactor and reacted at 180℃ for 5 hours. After the reaction, the mixture was centrifuged, filtered through a 0.22-micron pore size filter, dialyzed through a 1000 molecular weight cutoff dialysis bag for 48 hours, and finally freeze-dried to obtain glycosyl carbon quantum dots.

[0033] Example 4 A method for preparing glycosyl carbon quantum dots includes the following: 5g xylitol and 2g methylcyclohexanone oxime were added to 100g of 50wt.% ethanol solution and stirred until completely dissolved and evenly dispersed. The mixture was placed in a hydrothermal reactor lined with polytetrafluoroethylene and reacted at 180℃ for 4 hours. After the reaction, the mixture was centrifuged, filtered through a 0.22-micron pore size filter, dialyzed through a dialysis bag with a molecular weight cutoff of 1000 for 48 hours, and finally freeze-dried to obtain glycosyl carbon quantum dots.

[0034] Example 5 A method for preparing glycosyl carbon quantum dots includes the following: 5g of sucrose and 2g of cyclohexanone oxime were added to 100g of 40wt.% ethanol solution and stirred until completely dissolved and evenly dispersed. The mixture was placed in a hydrothermal reactor lined with polytetrafluoroethylene and reacted at 180℃ for 5 hours. After the reaction, the mixture was centrifuged, filtered through a 0.22-micron pore size filter, dialyzed through a dialysis bag with a molecular weight cutoff of 1000 for 48 hours, and finally freeze-dried to obtain glycosyl carbon quantum dots.

[0035] Example 6 A method for preparing glycosyl carbon quantum dots includes the following: 5g of N-acetyl-D-glucosamine and 2g of methylcyclohexanone oxime were added to 100g of a 50wt.% ethanol solution and stirred until completely dissolved and evenly dispersed. The mixture was placed in a polytetrafluoroethylene-lined hydrothermal reactor and reacted at 180℃ for 6 hours. After the reaction, the mixture was centrifuged, filtered through a 0.22-micron pore size filter, dialyzed through a 1000 molecular weight cutoff dialysis bag for 48 hours, and finally freeze-dried to obtain glycosyl carbon quantum dots.

[0036] Comparative Example 1 5g of glucose and 2g of n-octylamine were added to 100g of 50wt.% ethanol solution and stirred until homogeneous. The mixture was placed in a hydrothermal reactor lined with polytetrafluoroethylene and reacted at 180℃ for 6 hours. After the reaction, the mixture was centrifuged, filtered through a 0.22-micron pore size filter, dialyzed through a dialysis bag with a molecular weight cutoff of 1000 for 48 hours, and finally freeze-dried to obtain glycosyl carbon quantum dots.

[0037] Comparative Example 2 5g of glucose and 2g of dodecylamine were added to 100g of 50wt.% ethanol solution and stirred until homogeneous. The mixture was placed in a hydrothermal reactor lined with polytetrafluoroethylene and reacted at 180℃ for 6 hours. After the reaction, the mixture was centrifuged, filtered through a 0.22-micron pore size filter, dialyzed through a dialysis bag with a molecular weight cutoff of 1000 for 48 hours, and finally freeze-dried to obtain glycosyl carbon quantum dots.

[0038] Result characterization 1. The glycosyl carbon quantum dots prepared in Examples 1 to 6 were examined by transmission electron microscopy, and the particle size of the carbon quantum dots was statistically analyzed. The average particle size D was measured and is shown in Table 1.

[0039] Table 1 Particle Size Data

[0040] As shown in Table 1, the carbon quantum dots prepared in Examples 1 to 6 all have small particle sizes, less than 10 nm. Factors such as the type of carbon source and modifier, the amount of raw materials, and the reaction time all affect the particle size of the carbon quantum dots.

[0041] Transmission electron microscopy results as follows Figure 1 As shown, the obtained carbon quantum dots exhibit a quasi-spherical morphology, with particle sizes mainly distributed between 2 and 9 nm. Figure 2 The average particle size of the carbon quantum dots prepared in Example 1 is approximately 4.2 nm. This ultra-small size facilitates their flow and migration in low-permeability porous media. Meanwhile, no obvious aggregation was observed in the TEM image, indicating good colloidal dispersion stability. These structural and dispersion characteristics provide an important microstructural basis for the deep migration of carbon quantum dots prepared according to this invention in tight oil reservoirs and their enhanced oil recovery effect.

[0042] 2. Salt tolerance tests were performed on the glycosyl carbon quantum dots obtained in Examples 1-6 and Comparative Examples 1-2. Using a mineralization (NaCl) of 5 × 10⁻⁶, respectively... 4 Using mg / L mineralized water and deionized water as dispersion media, each sample was prepared into a dispersion with a mass fraction of 0.3 wt.%. All systems were kept consistent except for the dispersion medium. After ultrasonic dispersion for 30 min, the samples were sealed and aged at 45 ℃ for 7 days. Following aging, the median hydrated particle size (D) was determined using dynamic light scattering (DLS). 50 The D of mineralized water system and deionized water system 50 Differential evaluation of sample salt dispersion stability: in mineralized water D 50 The smaller the increase relative to deionized water, the better the salt-tolerant dispersion stability; the deionized water system was used as a control to eliminate the influence of temperature and static aging factors. The measured median hydrated particle size D... 50 As shown in Table 2.

[0043] Table 2. Hydrated Particle Size Data

[0044] Examples 1 to 6 were aged in mineralized water for 7 days, and D 50 Compared to deionized water, the increase was only slight, while the comparative ratio was observed in mineralized water. 50 The increase is significant, indicating that the use of ketoxime modifiers has a significant effect on improving the salt resistance of the product.

[0045] 3. Infrared spectroscopy analysis of the glycosyl carbon quantum dots prepared in Example 1. The results are as follows Figure 3As shown, its surface is rich in functional groups such as OH, NH, C=O, and -CH2-CH2, confirming the successful introduction of hydrophobic long chains during the synthesis process. This structure endows carbon quantum dots with higher interfacial activity, effectively improving oil recovery.

[0046] 4. The thermal stability of the glycosyl carbon quantum dots prepared in Example 1 was evaluated using thermogravimetric analysis (TGA). Approximately 10 mg of sample was placed in an alumina crucible and heated from 25 °C to 800 °C at a rate of 20 °C / min under a nitrogen protective atmosphere. The TG curve was recorded, and the thermal decomposition behavior and mass loss characteristics of the sample were analyzed to evaluate its thermal stability.

[0047] from Figure 4 As can be seen, the thermogravimetric behavior of the glycosyl carbon quantum dots prepared according to this invention exhibits a distinct three-stage characteristic. Below 220°C, the sample shows almost no significant mass loss, indicating good thermal stability in the low-temperature region. As the temperature rises to 220–550°C, the sample exhibits staged weight loss: the initial weight loss at 220–360°C is mainly attributed to the removal of surface adsorbed water and the thermal desorption / preliminary decomposition of some oxygen-containing functional groups; when the temperature further increases to 360–550°C, the weight loss rate increases significantly, mainly due to the further cracking and oxidative decomposition of organic groups and carbon skeletons on the carbon dot surface, accompanied by the release of volatile products such as CO / CO2. Above 550°C, the weight loss tends to end and enters a plateau region, with the residual mass corresponding to the char / inorganic residue of the sample.

[0048] It is worth noting that the initial significant weight loss temperature is about 220°C, which is higher than the formation temperature of most oil reservoirs (usually below 220°C), indicating that it has good temperature resistance stability and application potential in the thermal environment of oil reservoirs.

[0049] 5. The surface activity of the aqueous dispersion system of glycosyl carbon quantum dots prepared in Example 1 was evaluated by measuring the surface tension. The results are as follows Figure 5 As shown, the surface tension of the solution decreases significantly with increasing carbon quantum dot concentration, reaching a plateau value of 26.8 mN·m at approximately 0.3 wt%. - ¹, It has a good ability to reduce surface tension. It can be seen that the amphiphilic structure of the glycosyl carbon quantum dots prepared according to the present invention enables them to preferentially accumulate and adsorb at the gas-liquid interface, thereby reducing the interfacial free energy and significantly improving the interfacial activity.

[0050] 6. IFT between the glycosyl carbon quantum dot dispersion system prepared in Example 1 at different concentrations and n-decane Reducing the interfacial tension (IFT) between the aqueous and oil phases is one of the important ways to improve oil recovery. Based on this, the IFT between the glycosyl carbon quantum dot dispersions prepared in Example 1 at different concentrations and n-decane was measured; the results are as follows... Figure 6 As shown, the initial IFT of the n-decane / deionized water system is 51 mN·m - ¹; The addition of this carbon quantum dot significantly reduced IFT, decreasing to 4.8 mN·m at 0.3 wt%. - ¹. Notably, the concentration dependence of IFT is largely consistent with the trend of surface tension change with concentration, indicating that the glycosyl carbon quantum dots prepared according to this invention have significant interface regulation capabilities at both the gas-liquid and oil-water interfaces. Their amphiphilic characteristics drive the spontaneous enrichment and adsorption of particles at the oil-water interface, increasing interface coverage and reducing interfacial free energy, thereby effectively reducing IFT. The significantly reduced IFT suggests that it may promote residual oil mobilization by weakening capillary forces in porous media, providing a basis for its potential oil displacement applications.

[0051] 7. Wetting properties of the glycosyl carbon quantum dots prepared in Example 1 were tested. Changes in wettability are a key mechanism for enhanced oil recovery. The transition from a wetted state to a water-wet state typically alters capillary action and enhances the ability of spontaneous adsorption to mobilize retained oil. Oil-wetted glass slides were used as model solid surfaces to evaluate the wettability regulation effect of carbon quantum dots. After aging in the glycosyl carbon quantum dot dispersion prepared in Example 1, the aqueous contact angle of the sample surface significantly decreased from 120° to 55.7° (Figure 7), indicating that the glycosyl carbon quantum dots prepared according to this invention have a significant wettability modification capability.

[0052] 8. The glycosyl carbon quantum dots prepared in Examples 1 to 6 were respectively prepared into solutions with mass concentrations of 0.1wt%, 0.3wt%, and 0.5wt% for oil displacement tests.

[0053] The specific implementation steps are as follows: Outcrop sandstone (permeability 20 mD, porosity 15-17%) or artificial sandstone (diameter 25.32 mm, length 53.92 mm, permeability 4.52 mD, porosity 13.36%) is selected as the experimental core. After cleaning and drying, its geometric dimensions and mass are accurately measured. The gas porosity of the core is determined using a helium porosimeter. The core is placed in a -0.1 MPa vacuum environment for 12 hours, followed by saturation with simulated oil under the same pressure for 12 hours. The saturation is calculated by mass increment. The initial oil saturation of the artificial sandstone was 53.2%. The saturated oil core was aged for one week in a constant temperature environment of 90℃ (outcrop sandstone) or 60℃ (artificial sandstone). At room temperature, carbon quantum dot nanofluid or control tap water was injected at a constant rate of 0.2 mL / min. The experiment was stopped when the injected volume reached 4 PV and no oil precipitation occurred at the outlet. The viscosity of the displaced crude oil was 14.5 mPa·s. The volume of oil removed was measured using a graduated cylinder, and the recovery rate was determined by the ratio of the removed oil volume to the original saturated oil volume. The results are shown in Table 3. Table 3. Oil recovery data for glycosyl carbon quantum dot enhanced oil products.

[0054] Experimental data show that the prepared carbon quantum dots can significantly improve oil recovery, nearly doubling the efficiency compared to conventional waterflooding. Their nanoscale size and surface functional groups effectively regulate the activity of the oil-water-solid three-phase interface, exhibiting independent oil displacement enhancement characteristics without the need for surfactant assistance.

[0055] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing a glycosyl carbon quantum dot flooding agent for unconventional oil reservoirs, characterized in that, The method includes: adding a carbon source and a modifier to an alcohol solution, stirring to dissolve, and then carrying out a hydrothermal reaction to obtain the product; wherein the modifier includes at least one of cyclohexanone oxime, cyclopentanone oxime, cycloheptanone oxime, and methylcyclohexanone oxime.

2. The method according to claim 1, characterized in that, The carbon source includes sugars or their derivatives.

3. The method according to claim 1, characterized in that, The carbon source includes at least one of glucose, sucrose, xylitol, vitamin C, and N-acetyl-D-glucosamine.

4. The method according to claim 1, characterized in that, The mass ratio of the carbon source, modifier, and alcohol is 1~20:5~10:

100.

5. The method according to claim 1, characterized in that, The concentration of the alcohol solution is 40 wt.% to 60 wt.%.

6. The method according to claim 1, characterized in that, The hydrothermal reaction is carried out at a temperature of 180-200℃ for 4-8 hours.

7. The glycosyl carbon quantum dot flooding agent for unconventional oil reservoirs prepared by the method according to any one of claims 1 to 6.

8. The application of the sugar-based carbon quantum dot flooding agent for unconventional reservoirs as described in claim 7 in oil and gas extraction.

9. A method for improving the exploitation efficiency of unconventional oil reservoirs, characterized in that, The method described herein employs the unconventional reservoir oil displacement agent, as described in claim 7, for oil recovery.

10. A method for exploiting oil reservoirs in high-temperature and complex environments, characterized in that, The method described herein employs the unconventional reservoir oil displacement agent, as described in claim 7, for oil recovery.

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