Amidated polymethyl hydrocarbon ether gas-soluble foaming agent and preparation method thereof

Abstract

The invention belongs to the technical field of oil exploitation chemicals, and particularly provides an amidated polymethyl hydrocarbon ether gas-soluble foaming agent and a preparation method thereof. According to the invention, the amidated polymethyl hydrocarbon ether surfactant is used as the amidated polymethyl hydrocarbon ether gas-soluble foaming agent, so that the cost is low, and the method is suitable for large-scale industrial application of tertiary oil recovery; excellent gas solubility and foam stability under high-temperature and high-salt conditions are realized; meanwhile, the polymer has good solubility in CO2, and the effect that the polymer is carried and transported to a reservoir is good.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum mining chemicals, and in particular relates to an amidated polymethyl hydrocarbon ether gas-soluble foaming agent and a preparation method thereof. Background Art

[0002] By using CO 2 Injected into oil reservoirs as an oil displacement agent, using CO 2 Dissolving and reducing the viscosity of crude oil, expanding the volume of crude oil, and increasing the energy of the reservoir can not only improve the production capacity and recovery rate of the oil field, but also convert CO 2 Permanently stored underground, thus reducing the greenhouse gas content in the atmosphere. However, due to reservoir heterogeneity, CO 2 Viscous fingering caused by low viscosity and CO 2 The gravity overburden phenomenon caused by low density ultimately leads to low oil recovery and storage efficiency. 2 Water-based foam flooding and oil storage technology has improved the CO 2 The foam only accumulates around the injection wellbore, which cannot expand the scope of the foam and leads to high injection pressure difference, making it difficult for subsequent foam to be smoothly injected into the reservoir. At the same time, the foam far away from the wellbore is affected by gravity, causing differentiation and gas-liquid separation, and deep foam drive cannot be achieved. These seriously restrict the oil recovery effect and carbon sequestration effect of water-based foam.

[0003] CO 2 Aerosol foam refers to CO 2 After the gas-soluble foaming agent is dissolved in supercritical carbon dioxide, it is carried by the supercritical carbon dioxide through the wellbore into the oil reservoir, and foam is generated under the contact with formation water and the shearing action of the porous medium of the reservoir. Since the gas-soluble foaming agent can be carried by supercritical carbon dioxide, even if the foam breaks and fails, it can still be transported to the deep reservoir with the supercritical carbon dioxide, and the foam can be regenerated after contacting the formation water, thereby achieving the effects of deep sweep, flooding, and improving recovery. At the same time, the gas-soluble foam generation process will consume the bound water in the reservoir, further increasing the CO 2 In addition, the gas-soluble foam injection process is equivalent to gas injection rather than direct foam injection, so the gas-soluble foam is easier to inject, avoiding the problem of difficult injection.

[0004] The gas-soluble foaming agents currently proposed have the problems of high price, environmental pollution, poor foam stability, etc. Chinese patent CN114316939A discloses a carbon dioxide gas-soluble foaming agent, which is composed of a foaming agent main agent, a foam stabilizer, a foam promoter, a liquid film strengthener, an alkaline substance and a cosolvent. However, the composition of the gas-soluble foaming agent is complex and the preparation is cumbersome. Even after adding a low-carbon alcohol cosolvent, the liquid film strengthener and the alkaline substance still cannot be dissolved in supercritical carbon dioxide; at the same time, although the cosolvent can promote the dissolution of the foaming agent main agent, the foam stabilizer and the foam promoter in supercritical carbon dioxide, it will significantly reduce the stability of the foam. Therefore, the gas-soluble foaming agent can be carried by the supercritical carbon dioxide, but cannot form effective foam in the reservoir.

[0005] Chinese patent CN104774604A discloses a fluorinated polyurethane gas-soluble foaming agent, which is composed of allyl polyoxyethylene ether fluorinated polyurethane sulfonate sodium. However, the synthesis process of fluorinated gas-soluble foaming agents is complicated and the cost is extremely high. They cannot be used for large-scale tertiary oil recovery, and they have biological toxicity and poor biodegradability, which is not friendly to the environment. Chinese patent CN105255473A discloses a silicon-containing CO 2 Gas-soluble foaming agent, the foaming agent is prepared by catalysis of terminal hydrogen silicone oil, allyl polyoxyethylene ether sodium sulfate and alkylphenol polyoxyethylene ether by isopropanol solution of chloroplatinic acid, silicon-containing gas-soluble foaming agent also has high price, cannot be applied to large-scale tertiary oil recovery, and silicon-containing gas-soluble foaming agent is easy to hydrolyze, hydrogen ions and hydroxyl ions in water molecules react with silicon-oxygen bonds in silicon-containing foaming agent molecules, resulting in fracture, forming silanol or silicic acid, thereby causing the foaming agent to fail. The gas-soluble surfactant disclosed in Chinese patent CN103867169A is fatty alcohol polyoxyethylene polyoxypropylene ether or nonylphenol polyoxyethylene ether, and these two types of gas-soluble foaming agents have low solubility in supercritical carbon dioxide, and the foam stability formed in the reservoir is poor.

[0006] In summary, current gas-soluble foaming agents have limitations in terms of composition complexity, high cost, biological toxicity, easy hydrolysis, solubility in supercritical carbon dioxide and reservoirs, and foam stability. Summary of the invention

[0007] In order to solve the above problems, the present invention provides an amido polymethyl hydrocarbon ether gas-soluble foaming agent and a preparation method thereof. The amido polymethyl hydrocarbon ether gas-soluble foaming agent is simple to prepare, low in cost, and suitable for large-scale industrial application in tertiary oil recovery; it is not easy to hydrolyze, thus avoiding the gas-soluble foaming agent from failing in the reservoir; it is non-biologically toxic and environmentally friendly; it can form stable and effective gas-soluble foam in the reservoir with a small dosage; and it can also significantly increase carbon storage and crude oil recovery, thus achieving a win-win situation in economic and environmental benefits.

[0008] The technical solution of the present invention is as follows: In one aspect, the present invention provides an amido polymethyl hydrocarbon ether gas-soluble foaming agent, wherein the molecular structure of the amido polymethyl hydrocarbon ether gas-soluble foaming agent is: ; wherein the R group is any one of 3,5,5-trimethyl-1-hexyl, 2,3-dimethyl-2-heptyl, 2,4,4-trimethyl-1-pentyl, 2,2,4-trimethyl-3-pentyl, 3,4,5-trimethyl-4-heptyl, 3,4,4-trimethyl-3-pentyl, 2,3,4-trimethyl-3-pentyl, 2,3,3-trimethyl-2-pentyl, 2,4,6-trimethyl-4-heptyl, 2,4,4-trimethyl-2-pentyl, 2,6,6-trimethyl-4-heptyl, 3,4,4-trimethyl-1-pentynyl, 3,4,4-trimethyl-1-pentenyl, 3-(tert-butyl)-2,2,4,4,-tetramethylpentyl, 2,3,3-trimethyl-2-butyl, and 3-methyl-2-butyl; The value range of m is 5~20; the value range of n is 5~20. Among them, the polyoxypropylene group is the main CO-philic group in the molecular structure. 2 If the value of m is less than 5, the solubility of the gas-soluble surfactant in supercritical carbon dioxide will be less than 0.2 wt%. 2 The mass fraction of the aerosol surfactant carried is too low to form effective foam; when the value of m is higher than 20, the polyoxypropylene blocks will spirally stack at the gas-liquid interface to form a rugby-shaped accumulation, thereby destroying the tightly arranged structure of the foam liquid film, reducing the elasticity and density of the foam liquid film, and CO 2 The molecules easily diffuse and penetrate through the liquid film, which will cause the foam liquid precipitation half-life formed by the gas-soluble surfactant to be too short and the stability to be extremely poor, and it will not be able to achieve the purpose of effective oil displacement and sealing. The polyoxyethylene group is the main hydrophilic group in the molecular structure, and it is also the main foam stabilizing group. If the value range of n is lower than 5, the hydrophilic group will be too short and unable to penetrate into the water phase at the gas-liquid interface and form a strong hydrogen bond with the water. This will cause the hydration film thickness to become thinner and the hydrogen bond force between the surfactant molecules and the water phase to be weakened, which will cause the foam liquid film to break easily and the foam stability to become poor. If the value range of n is higher than 20, the solubility of the gas-soluble surfactant in supercritical carbon dioxide will be lower than 0.3wt%. 2 The mass fraction of the carried aerosol surfactant is too low to form effective foam, making it difficult to achieve the purpose of oil displacement and sealing.

[0009] In the present invention, the amide polymethyl hydrocarbon ether gas-soluble foaming agent increases CO 2The mechanism of action of solubility and foam stability is as follows: (1) Increase CO 2 Synergistic mechanism of solubility a. Synergistic effect of amide group and polyoxypropylene group (PO) Due to CO 2 The molecular electron cloud is unevenly distributed, and the carbon atom has partial positive charge, showing the characteristics of Lewis acid; while the carbonyl oxygen (C=O) and amino group (NH 2 ) has Lewis basicity and reacts with CO 2 The carbon atoms in the carbon atom produce Lewis acid-base interactions, and under supercritical conditions, CO 2 The molecules tend to be attracted to the amide groups. 2 The Lewis acid-base interaction between the molecules forms a stable microenvironment around the CO 2 The molecules provide more retention sites, reducing the competitive interaction between the PO group and other solvent molecules; the PO group then interacts with CO through its oxygen atom. 2 The polarity of the amide group increases the CO 2 The molecular capture efficiency is improved, so that the weak polarity of the PO group can be more fully exerted. The PO group, through its flexible chain segment and hydrophobic properties, makes the CO adsorbed by the amide group 2 The molecules are evenly distributed throughout the molecular system, avoiding the agglomeration effect of the molecules due to excessive polarity and improving the overall solubility.

[0010] b. Synergistic effect of amide group and R group The amide group provides a polar adsorption site in the molecule, and its strong polarity can effectively capture CO 2 Molecules. Capture of CO in the amide group 2 The R group further stabilizes the CO through its nonpolar properties. 2 The distribution of molecules reduces the repulsive effect of the amide group on the surrounding molecules, making the molecules as a whole in the CO 2 The amide group itself is a relatively rigid polar group, and its arrangement in the molecule may cause mutual attraction between polar groups within the molecule, thereby reducing its interaction with CO. 2 Due to its non-polarity and small size, the R group can provide steric hindrance, reduce the intramolecular aggregation between amide groups, and enable the amide groups to capture CO more efficiently. 2 molecular.

[0011] c. Synergistic effect between R group, polyoxypropylene and amide group The hydrophobic ether bond of the polyoxypropylene group can enhance the molecular adhesion to CO2 The interaction between them can improve the affinity of carbon dioxide and increase the permeability of carbon dioxide; the introduction of R group can significantly increase the free volume of the molecule, and the increase in free volume can provide more gaps, so that CO 2 The molecules penetrate and dissolve more easily around the surfactant molecules.

[0012] Since polyoxypropylene and R group increase CO 2 The molecular permeability allows the carbonyl and amino groups of the amide group to interact with multiple CO 2 The molecules produce Lewis acid-base interactions. Through the cumulative effect of this multi-point interaction, CO 2 The molecules are enriched around the amide groups, thus improving the overall solubility of the surfactant. Especially under supercritical conditions, CO 2 The increased mobility makes it easier to form dynamic Lewis acid-base interactions with amide groups, thereby further promoting the improvement of solubility.

[0013] 2. Synergistic mechanism for improving foam stability a. Synergistic effect of polyoxyethylene group (EO) and amide group Due to its flexible hydrophilic chain segment, the EO group can form a hydrogen bond network and intermolecular hydration to make the molecules in the liquid film more uniform and reduce the excessive aggregation between amide groups. In this way, the amide groups can be more effectively dispersed in the liquid film and give full play to their interfacial stabilization effect. The adsorption layer formed by the EO group at the gas-liquid interface has a certain flexibility and can alleviate the local fluctuation of the interfacial tension. In this way, even under high pressure or dynamic conditions, the interfacial adsorption force of the amide group is not easily weakened due to interfacial instability.

[0014] The amide group can react with the ethoxy group (–CH 2 –CH 2 –O–) forms a strong hydrogen bond network, which further enhances the hydration of the EO group, thereby improving the water retention capacity of the liquid film and delaying the drainage rate of the foam liquid film. 2 In the environment, the hydrophilic chain segments of the EO group will swell due to excessive adsorption of water, causing the liquid film to become fragile, while the amide group reduces the excessive expansion of the EO group by providing cohesive force, allowing the liquid film to maintain appropriate mechanical strength.

[0015] b. Synergistic effect of amide group and polyoxypropylene group The strong polarity of the amide group can cause polarity imbalance at the gas-liquid interface, especially in CO 2The high pressure of the foam causes uneven stretching of the liquid film, and the hydrophobicity of the PO group can neutralize the polar effect of the amide group, providing a hydrophobic barrier in the liquid film, thereby reducing the polarity difference inside the liquid film and enhancing the overall stability of the liquid film. In addition, the PO group can also enhance the mechanical toughness of the liquid film through its flexible chain segment, so that the liquid film can adapt to the deformation of the dynamic bubble film such as expansion, compression and shear. This flexible effect can help the amide group maintain the integrity of the hydrogen bond network when the liquid film is disturbed externally, thereby preventing the liquid film from rupturing.

[0016] The PO group is a weakly polar or hydrophobic group, and its adsorption capacity at the gas-liquid interface is limited when it exists alone. The amide group can significantly improve the adsorption capacity of the PO group at the gas-liquid interface through its polarity and hydrogen bonding. The hydrophobicity of the PO group contributes to the anti-drainage ability of the liquid film, but if the proportion of the PO group is too high, the hydrophobicity of the liquid film will be too strong, thereby weakening the water retention performance and interfacial stability of the liquid film. The amide group provides additional water retention capacity through its polarity, optimizes the hydrophilic-hydrophobic balance of the liquid film, and enables the liquid film to maintain a high toughness while preventing water from being lost too quickly.

[0017] c. Synergistic effect of R group and amide group The synergistic effect of R group and amide group plays a key role in the anti-coagulation property of the foam film. The R group forms the outer barrier of the liquid film through its hydrophobicity, while the amide group strengthens the inner structure of the liquid film through hydrogen bonding. This double-layer structure makes the liquid film anti-coagulation. The R group blocks the direct contact of bubbles, while the hydrogen bonding of the amide group further consolidates the inner structure of the film and delays the rupture of bubbles.

[0018] 3. Synergistic enhancement mechanism of each group in the overall structure-activity relationship of the molecule The amide group, polyoxyethylene group, PO group and R group work together to balance and complement each other, thus improving the molecular 2 Solubility and foam stability in: Balance of polarity and non-polarity: amide and EO groups provide polarity, increasing the interaction with water and foam stability; R and PO groups provide non-polarity, improving CO 2 The present invention achieves a balance between polar and non-polar structures by controlling the ratio of each group, so that the molecule has good compatibility at the interface between the two phases.

[0019] The synergistic effect of hydrogen bonding and hydrophobic barrier: The amide group and EO group increase the adhesion and stability of the liquid film through the hydrogen bonding network to prevent the bubble from bursting; the hydrophobicity of the R group and PO group forms a physical barrier at the interface to prevent the bubbles from coalescing and disappearing. This combination of hydrogen bonding and hydrophobic barrier gives the liquid film dual stability.

[0020] Molecular flexibility and conformational adaptability: The introduction of R and PO groups increases the flexibility of the molecule, making it 2 The polar part of the amide group provides structural support in the foam film through a hydrogen bond network. The hydrogen bond network provided by the amide group is mainly concentrated in the local area of ​​the molecule, specifically at the gas-liquid interface adsorption position of the molecular chain (such as the foam liquid film surface). This local effect will not significantly affect the flexibility of the entire molecule, especially the contribution of the R group and the PO group to the flexibility of the molecular main chain is still dominant. The flexible properties of the R group and the PO group can help the amide group to be evenly distributed at the liquid film interface through the free rotation of the molecular chain segment, thereby ensuring that the polar support effect of the amide group is fully exerted in the entire foam film; under high pressure CO 2 Under high pressure CO, the liquid film is easily subjected to external forces or compression, while the flexibility of the R and PO groups helps to disperse the stress, thereby protecting the hydrogen bond network formed by the amide groups from being destroyed prematurely. The synergistic effect of flexibility and support makes the foam 2 The environment remains stable.

[0021] The synergistic effect of each functional group improves the CO 2 of surfactants through the balance of polar and non-polar properties, the coordination of hydrogen bonds and hydrophobic barriers, and the combination of molecular flexibility and structural support. 2 Solubility and foam stability. Amide groups enhance CO 2 It plays a core bridging role in solubility and foam stability. Through its amphiphilicity and hydrogen bonding ability, it organically combines polar and non-polar groups, making the molecule both 2 It can dissolve in the water and form a stable foam structure on the interface.

[0022] On the other hand, the present invention also provides a method for preparing the amidated polymethyl hydrocarbon ether gas-soluble foaming agent, which comprises firstly subjecting polymethyl alcohol to a two-step polycondensation reaction with propylene oxide and ethylene oxide under the catalysis of an alkaline earth metal catalyst to obtain polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether, and then subjecting the polymethyl alcohol to an amidation reaction to obtain the final product.

[0023] The preparation method of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent comprises the following steps: Step 1, synthesis of polymethyl hydrocarbon alcohol polyoxypropylene ether: introducing propylene oxide into polymethyl alcohol and an alkaline earth metal catalyst to react and obtain polymethyl hydrocarbon alcohol polyoxypropylene ether; Step 2, synthesis of polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether: introducing ethylene oxide into the polymethyl hydrocarbon alcohol polyoxypropylene ether obtained in step 1 to react and obtain polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether; Step 3, synthesis of amidated polymethyl hydrocarbon ether: dissolve the polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether obtained in step 2 in anhydrous tetrahydrofuran, add triethylamine, and then add acetyl chloride to react to obtain a crude amidated polymethyl hydrocarbon ether product.

[0024] Step 4, separation and purification: The crude product of amidated polymethyl hydrocarbon ether obtained in step 3 is separated and purified to obtain amidated polymethyl hydrocarbon ether.

[0025] Specifically, the method for preparing the amidated polymethyl hydrocarbon ether gas-soluble foaming agent comprises the following steps: Step 1: Synthesis of polymethyl hydrocarbon alcohol polyoxypropylene ether In a high-temperature and high-pressure reactor, polymethyl alcohol and alkaline earth metal catalyst are added, propylene oxide is introduced after nitrogen purging for 10 to 15 minutes, and the reaction temperature is controlled at 125 to 135 °C for 1 to 10 hours to obtain polymethyl hydrocarbon alcohol polyoxypropylene ether.

[0026] Step 2: Synthesis of polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether After cooling the high temperature and high pressure reactor to 115-125 °C, the reaction temperature is controlled to be constant, ethylene oxide is introduced, and the reaction is continued for 1-10 h to obtain polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether, and the temperature is lowered and the material is discharged.

[0027] Step 3: Synthesis of amidated polymethyl hydrocarbon ether Dissolve polymethyl polyoxypropylene polyoxyethylene ether in anhydrous tetrahydrofuran to prepare a uniform solution, add triethylamine, and add acetyl chloride dropwise under stirring conditions, and control the reaction temperature to be 20-30°C; after adding acetyl chloride, keep the reaction mixture at 20-30°C and continue stirring for 1-2 hours to obtain a crude amidated polymethyl hydrocarbon ether product.

[0028] Step 4: Separation and purification The crude product of amidated polymethyl hydrocarbon ether is successively neutralized with glacial acetic acid, vacuum filtered, dissolved and filtered with ethyl acetate, rotary evaporated and vacuum dried to obtain amidated polymethyl hydrocarbon ether.

[0029] In step 1, the polymethyl alcohol is 3,5,5-trimethyl-1-hexanol, 2,3-dimethyl-2-heptanol, 2,4,4-trimethyl-1-pentanol, 2,2,4-trimethyl-3-pentanol, 3,4,5-trimethyl-4-heptanol, 3,4,4-trimethyl-3-pentanol, 2,3,4-trimethyl-3-pentanol, 2,3,3-trimethyl-2-pentanol, 2,4,6- One of trimethyl-4-heptanol, 2,4,4-trimethyl-2-pentanol, 2,6,6-trimethyl-4-heptyn-3-ol, 3,4,4-trimethyl-1-pentyn-3-ol, 3,4,4-trimethyl-1-penten-3-ol, 3-(tert-butyl)-2,2,4,4,-tetramethylpentan-3-ol, 2,3,3-trimethyl-2-butanol, and 3-methyl-2-butanol.

[0030] In step 1, the molar ratio of the polymethyl alcohol to propylene oxide is 1:(5-20); In step 1, the alkaline earth metal catalyst is a mixture of one or more of calcium hydroxide, barium hydroxide and magnesium hydroxide; In step 1, the added mass of the alkaline earth metal catalyst is 0.1-3.0% of the total mass of polymethyl alcohol, propylene oxide and ethylene oxide; The propylene oxide is introduced completely within 1 to 10 hours.

[0031] In step 2, the molar ratio of the polymethyl alcohol to ethylene oxide is 1:(5-20).

[0032] The ethylene oxide is introduced completely within 1 to 10 hours.

[0033] In step 3, the molar ratio of triethylamine to polymethyl alcohol is (1-1.5):1.

[0034] In step 3, the molar ratio of acetyl chloride to polymethyl alcohol is (1.0-1.1):1.

[0035] The beneficial effects of the present invention include but are not limited to: 1. The present invention proposes for the first time a gas-soluble foaming agent whose molecular structure is amidated polymethyl hydrocarbon ether.

[0036] Compared with fatty alcohol polyoxyethylene ether, the R group increases the molecular free volume, the terminal amide group and CO 2 The Lewis acid-base interaction of the molecule and the polyoxypropylene group together increase the CO 2 Affinity, amidated polymethyl hydrocarbon ether in CO 2 The solubility in the foam is higher; the amide group provides both hydrogen bond donors and acceptors, forming a hydrogen bond network at the gas-liquid interface, which significantly enhances the toughness and stability of the foam film. However, fatty alcohol polyoxyethylene ether lacks this hydrogen bond network, so the foam stability is poor.

[0037] Compared with fatty alcohol polyoxypropylene ether, amidated polymethyl hydrocarbon ether has better foam stability and foaming volume because the R group improves the chain rigidity, the polyoxyethylene group provides weak hydrophilicity, and the terminal amide group provides strong hydrophilicity so that the molecule as a whole remains amphiphilic.

[0038] Since fatty alcohol polyoxyethylene polyoxypropylene ether destroys the amphiphilic structure of the molecule itself (fatty alcohol is the lipophilic part, polyoxyethylene is the weakly hydrophilic part, and polyoxypropylene is the CO 2 part), while amido polymethyl hydrocarbon ether maintains an amphiphilic structure (R group is a lipophilic part, polyoxypropylene is a CO 2 The R group increases the molecular free volume, increases the single molecule adsorption area, and improves the rigidity of the tail chain, so that the amido polymethyl hydrocarbon ether has better gas solubility and foam stability under high temperature and high salt conditions, and reduces the amount of surfactant used, which is beneficial to cost saving.

[0039] 2. The amido-polymethyl hydrocarbon ether gas-soluble foaming agent prepared by the present invention has low manufacturing cost because it does not contain fluorocarbon structure and siloxane fragments, is suitable for large-dose injection in industrial tertiary oil recovery, has no biological toxicity, is environmentally friendly, will not undergo hydrolysis reaction when injected into the formation, and has high stability.

[0040] 3. The amido-polymethyl hydrocarbon ether gas-soluble foaming agent prepared by the present invention is a non-ionic surfactant, which can maintain a low adsorption amount in charged sandstone, carbonate, shale and other oil reservoir rocks, thereby reducing the loss of the foaming agent and further reducing the cost. Therefore, it is suitable for various types of oil reservoirs and has a wide range of applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is the infrared spectrum of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent of Example 1; Figure 2 is the hydrogen nuclear magnetic resonance spectrum of the amidated polymethyl hydrocarbon ether gas-soluble blowing agent of Example 1; Figure 3 is the carbon nuclear magnetic resonance spectrum of the amidated polymethyl hydrocarbon ether gas-soluble blowing agent of Example 1; Figure 4 This is the flow chart of the experimental device for effect verification; Figure 5 For CO 2 The amidated polymethyl hydrocarbon ether gas-soluble foaming agent of Example 1 improves the CO2 removal rate of high water-containing reservoirs 2 Injection volume of storage capacity-CO 2 Gas saturation diagram; Figure 6 For CO 2 The amidated polymethyl hydrocarbon ether gas-soluble foaming agent of Example 1 improves the CO2 removal rate of high water-containing reservoirs 2 Injection volume versus oil recovery efficiency diagram. DETAILED DESCRIPTION

[0042] The technical scheme of the present invention is further described below in conjunction with the accompanying drawings, embodiments and comparative examples of the specification, and the detailed description should not be considered as a limitation of the present invention, and the scope of protection of the present invention is not limited thereto. Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation of the specification of the present invention, which will be apparent to those skilled in the art. Other implementations obtained from the specification of the present invention will be apparent to the technician. The specification of the present invention and the embodiments are exemplary only.

[0043] Unless otherwise specified, the raw materials and catalysts in the examples of the present invention and the products in the comparative examples were purchased through commercial channels.

[0044] Example 1 This embodiment provides an amide-based polymethyl hydrocarbon ether gas-soluble foaming agent of acetamido 3,5,5-trimethyl-1-hexanol polyoxypropylene polyoxyethylene ether, and its molecular structure is as follows: .

[0045] The preparation method of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent is as follows: In a dry and clean high-temperature and high-pressure reactor with a stirrer, 1.0 mol (144 g) of 3,5,5-trimethyl-1-hexanol and 8.3 g of barium hydroxide catalyst were added, and high-purity nitrogen (purity greater than 99.999%) was purged for 15 minutes, and then 5 mol (290 g) of propylene oxide was introduced, and the reaction was completed in 2.5 hours. The reaction temperature was controlled at 130 ° C for 3 hours to obtain the product 3,5,5-trimethyl-1-hexanol polyoxypropylene ether. After cooling the reactor to 120 ° C, the reaction temperature was kept constant, and after 9 mol (396 g) of ethylene oxide was passed in 4.5 hours, the reaction was continued for 1.5 hours to obtain 3,5,5-trimethyl-1-hexanol polyoxypropylene polyoxyethylene ether, and the temperature was lowered and discharged. 3,5,5-trimethyl-1-hexanol polyoxypropylene polyoxyethylene ether was dissolved in anhydrous tetrahydrofuran to prepare a solution with a concentration of 0.5 g / mL, and then 1 mol (101 g) of triethylamine was added. Under stirring conditions, 1 mol (78 g) of acetyl chloride was added dropwise, and the reaction temperature was controlled to be 20 °C. After adding acetyl chloride, the reaction mixture was kept stirring at 30 °C for 1.5 hours to ensure complete reaction. Subsequently, acetamido 3,5,5-trimethyl-1-hexanol polyoxypropylene polyoxyethylene ether was obtained after neutralization with glacial acetic acid, vacuum filtration, ethyl acetate dissolution and filtration, rotary evaporation and vacuum drying.

[0046] like Figures 1 to 3 Shown are the infrared spectrum, hydrogen nuclear magnetic resonance spectrum, and carbon nuclear magnetic resonance spectrum of acetamido 3,5,5-trimethyl-1-hexanol polyoxypropylene polyoxyethylene ether, respectively. It can be seen from the figures that acetamido 3,5,5-trimethyl-1-hexanol polyoxypropylene polyoxyethylene ether was successfully prepared in this embodiment.

[0047] Example 2 This embodiment provides an amide-based polymethyl hydrocarbon ether gas-soluble foaming agent of acetamido 2,4,4-trimethyl-1-pentanol polyoxypropylene polyoxyethylene ether, and its molecular structure is as follows: .

[0048] The preparation method of the amidated polymethyl hydrocarbon ether foaming agent is as follows: In a dry and clean high-temperature and high-pressure reactor with a stirrer, 1.0 mol (130 g) of 2,4,4-trimethyl-1-pentanol and 14.1 g of calcium hydroxide catalyst were added, and high-purity nitrogen (purity greater than 99.999%) was purged for 12 min, and then 9 mol (522 g) of propylene oxide was introduced, and the reaction was completed in 4.5 h. The reaction temperature was controlled at 130 ° C for 5 h to obtain the product 2,4,4-trimethyl-1-pentanol polyoxypropylene ether. After cooling the reactor to 120 ° C, the reaction temperature was kept constant, and after 13 mol (572 g) of ethylene oxide was passed in 3.0 h, the reaction was continued for 2.5 h to obtain 2,4,4-trimethyl-1-pentanol polyoxypropylene polyoxyethylene ether, and the temperature was lowered and discharged. 2,4,4-trimethyl-1-pentanol polyoxypropylene polyoxyethylene ether was dissolved in anhydrous tetrahydrofuran to prepare a solution with a concentration of 0.6 g / mL, and then 1.3 mol (131.3 g) of triethylamine was added. Under stirring conditions, 1.1 mol (85.8 g) of acetyl chloride was added dropwise, and the reaction temperature was controlled to be 25 °C. After adding acetyl chloride, the reaction mixture was kept stirring at 30 °C for 1 hour to ensure that the reaction was complete. Subsequently, acetamido 2,4,4-trimethyl-1-pentanol polyoxypropylene polyoxyethylene ether was obtained after neutralization with glacial acetic acid, vacuum filtration, ethyl acetate dissolution and filtration, rotary evaporation and vacuum drying.

[0049] Example 3 This embodiment provides an amide-based polymethyl hydrocarbon ether gas-soluble foaming agent of acetamido 2,4,4-trimethyl-2-pentanol polyoxypropylene polyoxyethylene ether, and its molecular structure is as follows: .

[0050] The preparation method of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent is as follows: In a dry and clean high-temperature and high-pressure reactor with a stirrer, 1.0 mol (130 g) of 2,4,4-trimethyl-2-pentanol and 7.9 g of barium hydroxide catalyst were added, and high-purity nitrogen (purity greater than 99.999%) was purged for 13 min, and then 13 mol (754 g) of propylene oxide was introduced, and the reaction was completed in 6.0 h. The reaction temperature was controlled at 130 ° C for 6.5 h to obtain the product 2,4,4-trimethyl-2-pentanol polyoxypropylene ether. After cooling the reactor to 120 ° C, the reaction temperature was kept constant, and after 9 mol (396 g) of ethylene oxide was passed in 3.5 h, the reaction was continued for 3.5 h to obtain 2,4,4-trimethyl-2-pentanol polyoxypropylene polyoxyethylene ether, and the temperature was lowered and discharged. 2,4,4-trimethyl-2-pentanol polyoxypropylene polyoxyethylene ether was dissolved in anhydrous tetrahydrofuran to prepare a solution with a concentration of 0.5 g / mL, and then 1.2 mol (121.2 g) of triethylamine was added. Under stirring conditions, 1 mol (78 g) of acetyl chloride was added dropwise, and the reaction temperature was controlled to be 20 °C. After adding acetyl chloride, the reaction mixture was kept stirring at 20 °C for 2 hours to ensure that the reaction was complete. Subsequently, acetamido 2,4,4-trimethyl-2-pentanol polyoxypropylene polyoxyethylene ether was obtained after neutralization with glacial acetic acid, vacuum filtration, ethyl acetate dissolution and filtration, rotary evaporation and vacuum drying.

[0051] Example 4 This embodiment provides an amide-based polymethyl hydrocarbon ether gas-soluble foaming agent of acetamido 3-(tert-butyl)-2,2,4,4,-tetramethylpentan-3-ol polyoxypropylene polyoxyethylene ether, and its molecular structure is as follows: .

[0052] The preparation method of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent is as follows: In a dry and clean high-temperature and high-pressure reactor with a stirrer, 1.0 mol (200 g) of 3-(tert-butyl)-2,2,4,4,-tetramethylpentan-3-ol and 14.6 g of magnesium hydroxide catalyst were added, and high-purity nitrogen (purity greater than 99.999%) was purged for 13 minutes, and then 5 mol (290 g) of propylene oxide was introduced, and the reaction temperature was controlled at 130 ° C for 3 hours to obtain the product 3-(tert-butyl)-2,2,4,4,-tetramethylpentan-3-ol polyoxypropylene ether. After cooling the reactor to 120 ° C, the reaction temperature was kept constant, and after 5 mol (220 g) of ethylene oxide was introduced in 1.5 hours, the reaction was continued for 2.5 hours to obtain 3-(tert-butyl)-2,2,4,4,-tetramethylpentan-3-ol polyoxypropylene polyoxyethylene ether, and the temperature was lowered and discharged. 3-(tert-butyl)-2,2,4,4,-tetramethylpentan-3-ol polyoxypropylene polyoxyethylene ether was dissolved in anhydrous tetrahydrofuran to prepare a solution with a concentration of 0.6 g / mL, and then 1.5 mol (151.5 g) of triethylamine was added. Under stirring conditions, 1 mol (78 g) of acetyl chloride was added dropwise, and the reaction temperature was controlled to be 25 °C. After adding acetyl chloride, the reaction mixture was kept stirring at 20 °C for 1.8 hours to ensure that the reaction was complete. Subsequently, acetamido 3-(tert-butyl)-2,2,4,4,-tetramethylpentan-3-ol polyoxypropylene polyoxyethylene ether was obtained after neutralization with glacial acetic acid, vacuum filtration, ethyl acetate dissolution and filtration, rotary evaporation and vacuum drying.

[0053] Example 5 This embodiment provides an amide-based polymethyl hydrocarbon ether gas-soluble foaming agent of acetamido 2,3,3-trimethyl-2-butanol polyoxypropylene polyoxyethylene ether, and its molecular structure is as follows: .

[0054] The preparation method of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent is as follows: In a dry and clean high-temperature and high-pressure reactor with a stirrer, accurately weighed 1.0 mol (116 g) of 2,3,3-trimethyl-2-butanol and 12.9 g of magnesium hydroxide catalyst were added, and high-purity nitrogen (purity greater than 99.999%) was purged for 14 minutes, and then 9 mol (522 g) of propylene oxide was introduced, and the reaction was completed in 4.5 hours. The reaction temperature was controlled at 130 ° C for 3.5 hours to obtain the product 2,3,3-trimethyl-2-butanol polyoxypropylene ether. After cooling the reactor to 120 ° C, the reaction temperature was kept constant, and after 9 mol (396 g) of ethylene oxide was passed in 2.5 hours, the reaction was continued for 2.0 hours to obtain 2,3,3-trimethyl-2-butanol polyoxypropylene polyoxyethylene ether, and the temperature was lowered and discharged. 2,3,3-trimethyl-2-butanol polyoxypropylene polyoxyethylene ether was dissolved in anhydrous tetrahydrofuran to prepare a solution with a concentration of 0.6 g / mL, and then 1 mol (101 g) of triethylamine was added. Under stirring conditions, 1.1 mol (85.8 g) of acetyl chloride was added dropwise, and the reaction temperature was controlled to be 20 °C. After adding acetyl chloride, the reaction mixture was kept stirring at 25 °C for 1.5 hours to ensure complete reaction. Subsequently, acetamido 2,3,3-trimethyl-2-butanol polyoxypropylene polyoxyethylene ether was obtained after neutralization with glacial acetic acid, vacuum filtration, ethyl acetate dissolution and filtration, rotary evaporation and vacuum drying.

[0055] Example 6 This embodiment provides an acetamido 2,3-dimethyl-2-heptanol polyoxypropylene polyoxyethylene ether amido polymethyl hydrocarbon ether gas-soluble foaming agent, and its molecular structure is as follows: .

[0056] The preparation method of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent is as follows: In a dry, clean, high-temperature, high-pressure reactor equipped with a stirrer, 1.0 mol (144 g) of 2,3-dimethyl-2-heptanol and 8.1 g of calcium hydroxide catalyst were added, and high-purity nitrogen (purity greater than 99.999%) was purged for 13 min, and then 5 mol (290 g) of propylene oxide was introduced, and the reaction was completed in 2.5 h. The reaction temperature was controlled at 130 ° C for 2.5 h to obtain the product 2,3-dimethyl-2-heptanol polyoxypropylene ether. After cooling the reactor to 120 ° C, the reaction temperature was controlled to remain unchanged, and after 13 mol (572 g) of ethylene oxide was passed through in 3.5 h, the reaction was continued for 4.0 h to obtain 2,3-dimethyl-2-heptanol polyoxypropylene polyoxyethylene ether, and the temperature was lowered to discharge. 2,3,3-trimethyl-2-butanol polyoxypropylene polyoxyethylene ether was dissolved in anhydrous tetrahydrofuran to prepare a solution with a concentration of 0.5 g / mL, and then 1 mol (101 g) of triethylamine was added. Under stirring conditions, 1.1 mol (85.8 g) of acetyl chloride was added dropwise, and the reaction temperature was controlled to be 25 °C. After adding acetyl chloride, the reaction mixture was kept stirring at 25 °C for 1.7 hours to ensure that the reaction was complete. Subsequently, acetamido 2,3-dimethyl-2-heptanol polyoxypropylene polyoxyethylene ether was obtained after neutralization with glacial acetic acid, vacuum filtration, ethyl acetate dissolution and filtration, rotary evaporation and vacuum drying.

[0057] Example 7 This embodiment provides an acetamido 2,2,4-trimethyl-3-pentanol polyoxypropylene polyoxyethylene ether amido polymethyl hydrocarbon ether gas-soluble foaming agent, and its molecular structure is as follows: .

[0058] The preparation method of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent is as follows: In a dry and clean high-temperature and high-pressure reactor with a stirrer, 1.0 mol (130 g) of 2,2,4-trimethyl-3-pentanol and 6.1 g of barium hydroxide catalyst were added, and high-purity nitrogen (purity greater than 99.999%) was purged for 10 min, and then 9 mol (522 g) of propylene oxide was introduced, and the reaction was completed in 5.5 h. The reaction temperature was controlled at 130 ° C for 5.5 h to obtain the product 2,2,4-trimethyl-3-pentanol polyoxypropylene ether. After cooling the reactor to 120 ° C, the reaction temperature was kept constant, and after 5 mol (220 g) of ethylene oxide was passed through in 1.5 h, the reaction was continued for 1.5 h to obtain 2,2,4-trimethyl-3-pentanol polyoxypropylene polyoxyethylene ether, and the temperature was lowered and the material was discharged. 2,2,4-trimethyl-3-pentanol polyoxypropylene polyoxyethylene ether was dissolved in anhydrous tetrahydrofuran to prepare a solution with a concentration of 0.5 g / mL, and then 1.2 mol (121.2 g) of triethylamine was added. Under stirring conditions, 1.1 mol (85.8 g) of acetyl chloride was added dropwise, and the reaction temperature was controlled to be 28 °C. After adding acetyl chloride, the reaction mixture was kept stirring at 25 °C for 1.4 hours to ensure complete reaction. Subsequently, acetamido 2,2,4-trimethyl-3-pentanol polyoxypropylene polyoxyethylene ether was obtained after neutralization with glacial acetic acid, vacuum filtration, ethyl acetate dissolution and filtration, rotary evaporation and vacuum drying.

[0059] Example 8 This embodiment provides an amide-based polymethyl hydrocarbon ether gas-soluble foaming agent of acetamido 3,4,4-trimethyl-3-pentanol polyoxypropylene polyoxyethylene ether, and its molecular structure is as follows: .

[0060] The preparation method of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent is as follows: In a dry and clean high-temperature and high-pressure reactor with a stirrer, 1.0 mol (130 g) of 3,4,4-trimethyl-3-pentanol and 7.2 g of barium hydroxide catalyst were added, and high-purity nitrogen (purity greater than 99.999%) was purged for 11 minutes, and then 13 mol (754 g) of propylene oxide was introduced, and the reaction was completed in 6.5 hours. The reaction temperature was controlled at 130 ° C for 5.5 hours to obtain the product 3,4,4-trimethyl-3-pentanol polyoxypropylene ether. After cooling the reactor to 120 ° C, the reaction temperature was kept constant, and after 5 mol (220 g) of ethylene oxide was passed in 1.0 hour, the reaction was continued for 1.5 hours to obtain 3,4,4-trimethyl-3-pentanol polyoxypropylene polyoxyethylene ether, and the temperature was lowered and discharged. 3,4,4-trimethyl-3-pentanol polyoxypropylene polyoxyethylene ether was dissolved in anhydrous tetrahydrofuran to prepare a solution with a concentration of 0.6 g / mL, and then 1 mol (101 g) of triethylamine was added. Under stirring conditions, 1.1 mol (85.8 g) of acetyl chloride was added dropwise, and the reaction temperature was controlled to be 20 °C. After adding the acyl chloride, the reaction mixture was kept stirring at 25 °C for 1.5 hours to ensure that the reaction was complete. Subsequently, acetamido 3,4,4-trimethyl-3-pentanol polyoxypropylene polyoxyethylene ether was obtained after neutralization with glacial acetic acid, vacuum filtration, ethyl acetate dissolution and filtration, rotary evaporation and vacuum drying.

[0061] Example 9 This embodiment provides an amide-based polymethyl hydrocarbon ether gas-soluble foaming agent of acetamido 2,2,4-trimethyl-1-pentanol polyoxypropylene polyoxyethylene ether, and its molecular structure is as follows: .

[0062] The preparation method of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent is as follows: In a dry, clean, high-temperature, high-pressure reactor equipped with a stirrer, 1.0 mol (130 g) of 2,2,4-trimethyl-1-pentanol and 12.7 g of a mixture of magnesium hydroxide and barium hydroxide (5.8 g of magnesium hydroxide and 6.9 g of barium hydroxide) were added. After purging with high-purity nitrogen (purity greater than 99.999%) for 12 min, 13 mol (754 g) of propylene oxide was introduced, which was completed in 5.5 h. The reaction temperature was controlled at 130 °C for 6.0 h to obtain the product 2,2,4-trimethyl-1-pentanol polyoxypropylene ether. After cooling the reactor to 120 °C, the reaction temperature was controlled to remain unchanged. After 13 mol (572 g) of ethylene oxide was introduced in 3.5 h, the reaction was continued for 4.0 h to obtain 2,2,4-trimethyl-1-pentanol polyoxypropylene polyoxyethylene ether, and the material was discharged after cooling. 2,2,4-trimethyl-1-pentanol polyoxypropylene polyoxyethylene ether was dissolved in anhydrous tetrahydrofuran to prepare a solution with a concentration of 0.5 g / mL, and then 1.5 mol (151.5 g) of triethylamine was added. Under stirring conditions, 1 mol (78 g) of acetyl chloride was added dropwise, and the reaction temperature was controlled to be 30 °C. After adding acetyl chloride, the reaction mixture was kept stirring at 30 °C for 1.5 hours to ensure that the reaction was complete. Subsequently, acetamido 2,2,4-trimethyl-1-pentanol polyoxypropylene polyoxyethylene ether was obtained after neutralization with glacial acetic acid, vacuum filtration, ethyl acetate dissolution and filtration, rotary evaporation and vacuum drying.

[0063] Comparative Example 1 This comparative example uses lauryl alcohol polyoxyethylene ether as a foaming agent, and its structural formula is as follows: , Where n is 12.

[0064] Compared with the foaming agents prepared in Examples 1 to 9, the molecular structure of lauryl alcohol polyoxyethylene ether does not contain polymethyl groups, polyoxypropylene blocks, and amide groups.

[0065] Comparative Example 2 This comparative example uses lauryl alcohol polyoxypropylene ether as a foaming agent, and its structural formula is as follows: , Where n is 12.

[0066] Compared with the foaming agents prepared in Examples 1 to 9, the molecular structure does not contain polymethyl groups, polyoxyethylene blocks, and amide groups.

[0067] Comparative Example 3 This comparative example uses the aerosol surfactant disclosed in Chinese patent CN103867169A: fatty polymethyl alcohol polyoxyethylene polyoxypropylene ether, whose molecular structure is: , Among them, n=5, m=5.

[0068] Compared with the foaming agents prepared in Examples 1 to 9, the molecular structure of the comparative example does not contain an amide group, and the block sequence is different.

[0069] Comparative Example 4 This comparative example selects sodium dodecyl sulfate, i.e. SDS, a surfactant commonly used in oil fields.

[0070] Comparative Example 5 This comparative example is the same as Example 1, except that it does not have an amide group. The specific chemical formula is: .

[0071] For the CO in Examples 1 to 9 and Comparative Examples 1 to 5 2 Gas-soluble foaming agents are used in oil production. 2 The solubility and foam performance of the product were determined by the cloud point method and the Waring-Blender method. The solubility results are shown in Table 1 and the foam performance results are shown in Table 2.

[0072] Table 1 Solubility of blowing agents in supercritical carbon dioxide at 70 ℃ project Cloud point pressure (MPa) Dissolved mass fraction (%) Example 1 14.23 0.5 Example 2 13.71 0.5 Example 3 13.23 0.5 Example 4 14.36 0.5 Example 5 13.65 0.5 Example 6 13.29 0.5 Example 7 13.51 0.5 Example 8 13.42 0.5 Example 9 13.83 0.5 Comparative Example 1 24.36 0.5 Comparative Example 2 16.39 0.5 Comparative Example 3 21.91 0.5 Comparative Example 4 / 0.5 Comparative Example 5 15.10 0.5 Table 2 Foam properties of foaming agents in various examples and comparative examples project Dialysis half-life (min) Foaming volume (mL) Foam comprehensive value (mL·min) Example 1 14.55 535 7784.25 Example 2 15.27 540 8245.80 Example 3 13.62 525 7150.50 Example 4 15.26 495 7553.70 Example 5 15.64 560 8758.40 Example 6 15.91 570 9068.70 Example 7 13.56 535 7254.60 Example 8 14.46 540 7808.40 Example 9 14.32 530 7589.60 Comparative Example 1 7.18 499 3582.82 Comparative Example 2 4.36 320 1395.20 Comparative Example 3 5.14 467 2400.38 Comparative Example 4 5.85 596 3486.60 Comparative Example 5 12.04 521 6272.84 As shown in Table 1, the solubility of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent of the present invention is relatively high, which is due to the introduction of CO 2 The free volume of the groups (PO groups and terminal amide groups) and the R groups is increased.

[0073] As shown in Table 2, the foam properties measured using a foaming agent with a mass fraction of 0.5%. It can be seen from Table 2 that the foaming ability and foam stability of the amidated polymethyl hydrocarbon ether carbon dioxide gas-soluble foaming agent in Examples 1 to 9 are relatively high. This is because the gas-soluble foaming agent of the present invention maintains amphiphilicity as a whole due to the block sequence of the molecular structure, while the R group increases the molecular free volume, and the terminal amide group increases the thickness of the foam liquid film through hydrogen bonding.

[0074] Among them, Comparative Example 4 does not contain CO 2 The group is insoluble in supercritical carbon dioxide and its cloud point pressure cannot be measured.

[0075] Compared with the polymethyl polyoxyethylene polyoxypropylene ether in comparative example 3, examples 1-9 use polymethyl groups as R groups, which are not only methylated at the end of the tail chain, but also highly methylated at specific positions of the side chains; comparative example 3 lacks R groups and amide groups with a specific combination strategy, resulting in low solubility. In examples 1-9, the amidated polymethyl hydrocarbon ether gas-soluble foaming agent not only introduces methyl groups into the hydrophobic chain through a unique polymethylated hydrocarbon chain modification strategy, but also arranges methyl groups at specific positions and sequences of the main chain and the side chains, thereby achieving CO 2 The optimal balance between solubility and foam stability is achieved, rather than just point methylation at the tail or chain end. Examples 1-9 use a unique arrangement sequence of R group chain-PO chain-EO chain-terminal amide group in the molecular design, which is different from the single EO chain, PO chain or disordered EO-PO chain in Comparative Example 3. This unique structural arrangement allows the molecule to be 2 In addition, compared with Comparative Example 3, Examples 1-9 introduced amide groups, which significantly improved the molecular and CO 2 The interaction between the two groups enhances the adhesion and toughness of the liquid film through polar effects and hydrogen bond networks, thereby delaying the collapse of the foam and improving the CO 2 In addition, the R-group chains in Examples 1-9 not only increase the hydrophobicity and flexibility of the molecules, but also build a stable hydrophobic barrier, significantly improving the gas dispersion and stability of the foam, which is in sharp contrast to the design use and function of the polymethyl alcohol polyoxyethylene polyoxypropylene ether used in the microemulsion in Comparative Example 3. Compared with Comparative Example 5, Example 1 introduces an amide group, which significantly improves the molecular 2 The interaction between the two groups enhances the adhesion and toughness of the liquid film through polar effects and hydrogen bond networks, thereby delaying the collapse of the foam and improving the CO 2 Solubility and foam stability.

[0076] Effect verification example 1 Experimental steps: follow Figure 4 Connect the experimental device, that is, store crude oil, formation water, and CO 2 and CO 2 -One end of the intermediate container of the foaming agent mixture is connected to the ISCO plunger pump through a six-way valve, and the other end is connected to the inlet end of the core holder and the computer through a six-way valve. The outlet end of the core holder is connected to the back pressure valve and the measuring cylinder in sequence, and the measuring cylinder is used to receive the produced fluid.

[0077] The foaming agent is the amide-based polymethyl hydrocarbon ether gas-soluble foaming agent of acetamide-based 3,5,5-trimethyl-1-hexanol polyoxypropylene polyoxyethylene ether in Example 1.

[0078] The core holder is a sand-filled tube simulating a high water-cut reservoir, and the preparation method thereof is as follows: the sand-filled tube is filled with crude oil at an injection rate of 1 mL / min using an ISCO plunger pump, and the temperature of the sand-filled tube is maintained at 65°C and the pressure is maintained at 20 MPa during the whole process; after the sand-filled tube is saturated with oil, the initial oil saturation is 81.8%, and the viscosity of the experimental oil at 65°C is 20 mPa·s; the sand-filled tube is placed in a 65°C oven for constant temperature aging for 48 h, and then a water flooding experiment is carried out at an injection rate of 1 mL / min at 65°C and 20 MPa; after 4.018 PV of water flooding, the oil saturation in the sand-filled tube is reduced to 23.3%, and the water saturation is increased to 76.7%, and a sand-filled tube simulating a high water-cut reservoir is prepared.

[0079] The sand-filled tube has a permeability of 872 mD, a pore volume of 57.6 mL, and a total length of 1 m.

[0080] Gas-soluble foaming agent flooding: CO 2 An intermediate container containing a gas-soluble foaming agent is introduced, and the two are mixed evenly in the intermediate container. During the mixing process, the stirring rotor is started to accelerate the phase equilibrium. The mass percentage of the gas-soluble foaming agent and supercritical carbon dioxide when mixed is 0.3%, the pressure is 20 MPa, and the temperature is 65 °C; the above uniform mixture is injected into the core holder through an ISCO plunger pump at an injection rate of 1 mL / min, and the inlet and outlet ends of the core holder are injected and produced simultaneously. During the whole process, the back pressure at the output end is maintained at 20 MPa through the back pressure valve, and the temperature of the core holder is 65 °C.

[0081] CO 2 Drive: Open the CO 2 The intermediate container was injected into the core holder by an ISCO plunger pump at an injection rate of 1 mL / min, and the inlet and outlet ends of the core holder were injected and produced simultaneously. During the whole process, the back pressure at the production end was maintained at 20 MPa through the back pressure valve, and the temperature of the core holder was 65 °C.

[0082] Result analysis: Figure 5 and Figure 6 The results show that the amidated polymethyl hydrocarbon ether gas-soluble foaming agent of Example 1 can be used to improve the CO 2 Injection volume of storage capacity-CO 2Gas saturation diagram and injection volume-oil recovery efficiency diagram, the specific data are shown in Table 3 and Table 4. The results show that after displacing 2.71 PV, the gas-soluble foam can increase the carbon dioxide storage capacity of high water-content reservoirs to about 92.14% and the oil recovery rate to about 94%; while after supercritical carbon dioxide displaces 4.82 PV, the carbon dioxide storage capacity of high water-content reservoirs reaches about 31.82%, and the oil recovery rate reaches about 68.80%. This shows that after a small amount of gas-soluble foam is injected, both the carbon dioxide storage capacity and the oil recovery rate are much higher than supercritical carbon dioxide flooding, achieving a win-win situation in terms of economy and environment.

[0083] Table 3 CO 2 Injection volume-gas phase saturation of the gas-soluble foaming agent flooding prepared in Example 1

[0084] Table 4 CO 2 Injection volume-displacement efficiency of the gas-soluble foaming agent flooding prepared in Example 1

[0085] Any equivalent structure or equivalent process transformation based on the amidated polymethyl hydrocarbon ether gas-soluble foaming agent described in the present invention, or direct or indirect application to other related technical fields, is included in the patent protection scope of the present invention. The embodiments of the present invention are only examples and do not limit the patent scope of the present invention.

Claims

1. An amidated polymethyl hydrocarbon ether gas-soluble foaming agent, characterized in that: The molecular structural formula of the amidated polymethyl hydrocarbon ether gas-soluble foaming agent is: ； wherein the R group is any one of 3,5,5-trimethyl-1-hexyl, 2,3-dimethyl-2-heptyl, 2,4,4-trimethyl-1-pentyl, 2,2,4-trimethyl-3-pentyl, 3,4,5-trimethyl-4-heptyl, 3,4,4-trimethyl-3-pentyl, 2,3,4-trimethyl-3-pentyl, 2,3,3-trimethyl-2-pentyl, 2,4,6-trimethyl-4-heptyl, 2,4,4-trimethyl-2-pentyl, 2,6,6-trimethyl-4-heptyl, 3,4,4-trimethyl-1-pentynyl, 3,4,4-trimethyl-1-pentenyl, 3-(tert-butyl)-2,2,4,4,-tetramethylpentyl, 2,3,3-trimethyl-2-butyl, and 3-methyl-2-butyl; The value range of m is 5~20; the value range of n is 5~20.

2. A method for preparing the amidated polymethyl hydrocarbon ether gas-soluble foaming agent as claimed in claim 1, characterized in that: Firstly, polymethyl alcohol is subjected to a two-step polycondensation reaction with propylene oxide and ethylene oxide under the catalysis of an alkaline earth metal catalyst to obtain polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether, and then polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether is subjected to an amidation reaction with triethylamine and acetyl chloride to obtain an amidated polymethyl hydrocarbon ether gas-soluble foaming agent; The molar ratio of the polymethyl alcohol to propylene oxide is 1:(5-20); The molar ratio of the polymethyl alcohol to ethylene oxide is 1:(5-20); The molar ratio of triethylamine to polymethyl alcohol is (1-1.5):1; The molar ratio of acetyl chloride to polymethyl alcohol is (1.0-1.1):

1.

3. The method for preparing the amidated polymethyl hydrocarbon ether gas-soluble foaming agent according to claim 2, characterized in that: The following steps are involved: Step 1, synthesis of polymethyl hydrocarbon alcohol polyoxypropylene ether: introducing propylene oxide into polymethyl alcohol and an alkaline earth metal catalyst to react and obtain polymethyl hydrocarbon alcohol polyoxypropylene ether; Step 2, synthesis of polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether: introducing ethylene oxide into the polymethyl hydrocarbon alcohol polyoxypropylene ether obtained in step 1 to react and obtain polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether; Step 3, synthesis of amidated polymethyl hydrocarbon ether: dissolving the polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether obtained in step 2 in anhydrous tetrahydrofuran, adding triethylamine, and then adding acetyl chloride to react, to obtain a crude product of amidated polymethyl hydrocarbon ether; Step 4, separation and purification: The crude product of amidated polymethyl hydrocarbon ether obtained in step 3 is separated and purified to obtain amidated polymethyl hydrocarbon ether.

4. The method for preparing the amidated polymethyl hydrocarbon ether gas-soluble foaming agent according to claim 2, characterized in that: The following steps are included: Step 1: Synthesis of polymethyl hydrocarbon alcohol polyoxypropylene ether: In a high-temperature and high-pressure reactor, polymethyl alcohol and alkaline earth metal catalyst are added, propylene oxide is introduced after nitrogen purge for 10-15 minutes, and the reaction temperature is controlled at 125-135°C for 1-10 hours to obtain polymethyl hydrocarbon alcohol polyoxypropylene ether; Step 2: Synthesis of polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether: After cooling the high temperature and high pressure reactor to 115-125°C, the reaction temperature is kept constant, ethylene oxide is introduced, and the reaction is continued for 1-10 hours to obtain polymethyl hydrocarbon alcohol polyoxypropylene polyoxyethylene ether, and the temperature is lowered and the material is discharged; Step 3: Synthesis of amidated polymethyl hydrocarbon ether: Dissolve polymethyl polyoxypropylene polyoxyethylene ether in anhydrous tetrahydrofuran to prepare a uniform solution, then add triethylamine, and add acetyl chloride dropwise under stirring conditions, and control the reaction temperature to be 20-30°C; after adding acetyl chloride, keep the reaction mixture at 20-30°C and continue stirring for 1-2 hours to obtain a crude amidated polymethyl hydrocarbon ether product; Step 4: Separation and purification: The crude product of amidated polymethyl hydrocarbon ether is successively neutralized with glacial acetic acid, vacuum filtered, dissolved and filtered with ethyl acetate, rotary evaporated and vacuum dried to obtain amidated polymethyl hydrocarbon ether.

5. The method for preparing the amidated polymethyl hydrocarbon ether gas-soluble foaming agent according to claim 3, characterized in that: In step 1, the polymethyl alcohol is 3,5,5-trimethyl-1-hexanol, 2,3-dimethyl-2-heptanol, 2,4,4-trimethyl-1-pentanol, 2,2,4-trimethyl-3-pentanol, 3,4,5-trimethyl-4-heptanol, 3,4,4-trimethyl-3-pentanol, 2,3,4-trimethyl-3-pentanol, 2,3,3-trimethyl-2-pentanol, 2,4,6- One of trimethyl-4-heptanol, 2,4,4-trimethyl-2-pentanol, 2,6,6-trimethyl-4-heptyn-3-ol, 3,4,4-trimethyl-1-pentyn-3-ol, 3,4,4-trimethyl-1-penten-3-ol, 3-(tert-butyl)-2,2,4,4,-tetramethylpentan-3-ol, 2,3,3-trimethyl-2-butanol, and 3-methyl-2-butanol.

6. The method for preparing the amidated polymethyl hydrocarbon ether gas-soluble foaming agent according to claim 3, characterized in that: In step 1, the alkaline earth metal catalyst is a mixture of one or more of calcium hydroxide, barium hydroxide and magnesium hydroxide.

7. The method for preparing the amidated polymethyl hydrocarbon ether gas-soluble foaming agent according to claim 6, characterized in that: In step 1, the added mass of the alkaline earth metal catalyst is 0.1-3.0% of the total mass of the polymethyl alcohol, propylene oxide and ethylene oxide.

8. The method for preparing the amidated polymethyl hydrocarbon ether gas-soluble foaming agent according to any one of claims 2 to 7, characterized in that: The propylene oxide is introduced completely within 1 to 10 hours.

9. The method for preparing the amidated polymethyl hydrocarbon ether gas-soluble foaming agent according to any one of claims 2 to 7, characterized in that: The ethylene oxide is introduced completely within 1 to 10 hours.

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