A composite surfactant for oil displacement, an oil displacement composition, an oil displacement agent, and an application containing a biobased cationic surfactant

Abstract

The application relates to the field of oilfield exploitation, and particularly discloses a composite surfactant which comprises a bio-based cationic surfactant and an anionic surfactant and / or a nonionic surfactant, wherein the bio-based cationic surfactant contains a compound as shown in formula (1) and / or a compound as shown in formula (2): in formula (1) and (2), at least one of R2, R3 and R4 is -Poly-OH; wherein -Poly- is at least one selected from - (PO) m1 - (EO) m2 - (BO) m3 -. The composite surfactant has super strong interfacial properties and wetting change properties, overcomes the problem of low activity of traditional alkyl benzyl quaternary ammonium salt and alkyl alcohol anionic nonionic surfactant compounding, can achieve super high interfacial activity, and further reduces the influence on the environment because of avoiding the use of alkyl phenol products.

Description

Technical Field

[0001] This invention relates to the field of oilfield development, and specifically to a composite surfactant for oil displacement containing a bio-based cationic surfactant, an oil displacement composition, an oil displacement agent, and its application. Background Technology

[0002] The technology of compounding anionic and cationic surfactants has broken through traditional limitations and has achieved considerable success in the field of enhanced oil recovery. To meet increasingly stringent environmental requirements, anionic surfactants are increasingly adopting environmentally friendly products such as alkyl alcohols without alkylphenols. Cationic surfactants, in addition to traditional quaternary ammonium salt surfactants with hydrophobic alkyl groups, often employ cationic surfactants containing benzyl groups. However, these cationic surfactants have high critical micelle concentrations and low surface activity, making it difficult to meet the needs of complex reservoirs, especially heavy oil reservoirs with high aromatic content.

[0003] Therefore, the development of novel anionic and cationic surfactants, such as alkylphenol-free anionic surfactants, is a current research trend.

[0004] Rosin is an abundant and inexpensive natural renewable chemical raw material. It possesses a tricyclic diterpenoid framework structure and has excellent hydrophobic groups. my country has abundant rosin production, making it a resource-rich country with a significant advantage in developing rosin-based surfactants. Research on rosin surfactants has mainly focused on anionic and nonionic surfactants. Rosin-based polyoxyethylene ethers can be used as emulsifiers for asphalt, but their direct application is not widespread. Furthermore, there are few reports on the synthesis and properties of rosin cationic surfactants. How to utilize rosin to obtain novel cationic surfactants, improve their surface activity, and further enhance the surface activity of composite surfactants compounded with anionic and nonionic surfactants for oil displacement, thereby improving oil displacement efficiency, is an important research topic of this invention. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this invention provides a composite surfactant for oil displacement containing a bio-based cationic surfactant, an oil displacement composition, an oil displacement agent, and its application. This invention employs a novel composite composition of a bio-based cationic surfactant and anionic surfactant, exhibiting superior interfacial and wetting-modifying properties. This significantly reduces the critical micelle concentration and improves the oil displacement efficiency of the composition. It overcomes the problem of low activity in traditional composites of alkyl benzyl quaternary ammonium salts and alkyl alcohol anionic nonionic surfactants. Not only does it achieve ultra-high interfacial activity, but it also further reduces environmental impact by avoiding the use of alkylphenol products. The composite surfactant of this invention can improve compatibilization parameters, reduce oil-water interfacial tension, increase oil washing rate, and enhance oil recovery in oil displacement applications.

[0006] A first aspect of the present invention is to provide a composite surfactant comprising a bio-based cationic surfactant, and an anionic surfactant and / or a nonionic surfactant, said bio-based cationic surfactant containing a compound as shown in formula (1) and / or a compound as shown in formula (2):

[0007]

[0008]

[0009] In formulas (1) and (2), R2, R3, and R4 are each independently selected from hydrogen, C1-C4 alkyl groups, and C6-C4 alkyl groups. 10 It has at least one of the aromatic group and -Poly-OH, and at least one of R2, R3, and R4 is -Poly-OH; wherein -Poly- is selected from -(PO). m1 -、-(EO) m2 -、-(BO) m3 - at least one of the following, wherein m1, m2, and m3 are each 0 to 20, for example 0, 2, 4, 6, 8, 15, 20, and any two values ​​or any interval of any two values.

[0010] According to the present invention, the compounds represented by formulas (1) and (2) can be used as cationic surfactants. Furthermore, these compounds can be compounded with anionic surfactants to form compositions exhibiting superior interfacial and wetting-modifying properties, significantly reducing the critical micelle concentration and improving the oil displacement efficiency of the compositions. This overcomes the problem of low activity in traditional combinations of alkyl benzyl quaternary ammonium salts and alkyl alcohol anionic nonionic surfactants, achieving not only ultra-high interfacial activity but also further reducing environmental impact by avoiding the use of alkylphenol products. The composite surfactant for oil displacement of the present invention can improve compatibilization parameters, reduce oil-water interfacial tension, and increase oil recovery in oil displacement applications.

[0011] According to the present invention, X - X is an anion. - The selection can be made within a wide range. In a preferred embodiment of the present invention, X - It is a halide ion, preferably Cl. - and / or Br - .

[0012] In a preferred embodiment of the present invention, -Poly- is selected from -(PO). m1 -、-(EO) m2 -、-(BO) m3At least one of the following, wherein m1+m2+m3 is 0-50, preferably 2-20, for example 0, 2, 4, 6, 8, 10, 15, 20, and any two values ​​or any interval of any two values.

[0013] More preferably, two of R2, R3, and R4 are independently C1-C4 alkyl groups or C6-C4 alkyl groups. 10 The aromatic group is either -Poly-OH, or -Poly- is selected from -(PO). m1 -、-(EO) m2 -、-(BO) m3 At least one of the following, wherein m1+m2+m3 is 0-50, preferably 2-20, for example 0, 2, 4, 6, 8, 10, 15, 20, and any two values ​​or any interval of any two values.

[0014] According to the present invention, the compounds represented by formula (1) and formula (2) can be prepared with reference to existing techniques. For example, the compounds of the present invention can be obtained by first performing an alkylation reaction followed by an ethoxylation reaction, and then performing a quaternization reaction. As an example, the compounds represented by formula (1) and formula (2) of the present invention can be prepared by the following methods:

[0015] Step A: Alkylation reaction: At least one of dehydrorosin amine and rosin amine is reacted with an alkylating agent to obtain alkyldehydrorosin amine;

[0016] Step B: Ethoxylation: The reaction product obtained in step A is reacted with at least one of ethylene oxide, propylene oxide, and butane oxide in the presence of a catalyst to obtain alkyl dehydrogenated rosin amine polyoxyethylene ether.

[0017] Step C: Quaternization: The alkyl dehydrorosin amine polyoxyethylene ether is subjected to a quaternization reaction with an alkylating agent to obtain the cationic surfactant.

[0018] Preferably, the catalyst is selected from at least one of alkali metal hydroxides, DMC bimetallic polyether catalysts, and phosphazene catalysts.

[0019] Preferably, the alkylating agent is selected from at least one of halogenated alkanes, such as bromoalkanes or chloroalkanes; and / or, the molar ratio of the total amount of the dehydrorosinamine and rosinamine to the total amount of the alkylating agent is 1:3.

[0020] The reaction conditions in steps A and C include: a reaction temperature of 70–150°C and a reaction pressure of 0–5 MPa; and / or, the reaction conditions in step B include: a reaction temperature of 140–200°C and a reaction pressure of 0–5 MPa; and / or, the molar ratio of the total amount of dehydrogenated rosin amine and rosin amine to the total amount of added ethylene oxide, propylene oxide, and butyl oxide is 1:(1–50); and / or, the weight ratio of the amount of catalyst to the total amount of dehydrogenated rosin amine and rosin amine is (0.001%–2.0%):1.

[0021] As an example, more specifically, the preparation method of the cationic surfactant shown in formula (1) includes the following steps: Step a: reacting dehydrorosin amine with an alkylating agent (chloromethane) at a molar ratio of 1:2, a reaction temperature of 120°C, and a reaction pressure of 2.5 MPa to obtain alkyl chloride dehydrorosin amine quaternary ammonium salt; Step b: reacting the product of step a with ethylene oxide and sodium hydroxide catalyst at a reaction temperature of 150°C and a reaction pressure of 3 MPa to obtain alkyl dehydrorosin amine polyoxyethylene ether; Step c: quaternizing the alkyl dehydrorosin amine polyoxyethylene ether with an alkylating agent to obtain the cationic surfactant, wherein the molar ratio of the dehydrorosin amine to the added ethylene oxide is 1:2, 1:4, and 1:6, respectively, to obtain different specific types of cationic surfactants shown in formula (1), corresponding to the specific types of cationic surfactants in Examples 1, 2, and 3 in Table 1.

[0022] As an example, more specifically, the preparation method of the cationic surfactant shown in formula (2) includes the following steps: Step a: reacting rosin amine with an alkylating agent (chloromethane) at a molar ratio of 1:2, at a reaction temperature of 130°C and a reaction pressure of 2.6 MPa to obtain alkyl chlorinated rosin amine quaternary ammonium salt; Step b: mixing the reaction product of step a with ethylene oxide and sodium hydroxide catalyst for reaction at a reaction temperature of 160°C and a reaction pressure of 3.5 MPa; Step c: quaternizing the alkyl rosin amine polyoxyethylene ether with an alkylating agent to obtain the cationic surfactant, wherein the molar ratio of the rosin amine to the added ethylene oxide is 1:2, 1:4, and 1:6, respectively, to obtain different specific types of cationic surfactants shown in formula (2), corresponding to the specific types of cationic surfactants in Examples 7, 8, and 9 in Table 3.

[0023] According to the present invention, the composite surfactant includes a bio-based cationic surfactant, as well as anionic surfactants and / or nonionic surfactants. In a preferred embodiment of the present invention, the composite surfactant includes the bio-based cationic surfactant and anionic-nonionic surfactant.

[0024] According to the present invention, the anionic-nonionic surfactant can be selected from a wide range. In a preferred embodiment of the present invention, the anionic-nonionic surfactant is a fatty alcohol anionic-nonionic surfactant; preferably, it is a fatty alcohol polyoxyethylene / polyoxypropylene ether carboxylate, and / or a fatty alcohol polyoxyethylene ether / polyoxypropylene ether sulfonate; more preferably,

[0025] The anionic-nonionic surfactant is selected from at least one of tridecyl alcohol polyoxyethylene ether (5EO) sulfonate, tridecyl alcohol polyoxyethylene ether (5EO) polyoxypropylene (2PO) sulfonate, decaalkyl alcohol polyoxyethylene ether (3EO) carboxylate, decaalkyl alcohol polyoxyethylene ether (3EO) carboxylate, and dodecyl alcohol polyoxyethylene ether (5EO) carboxylate.

[0026] The anionic-nonionic surfactants can all be prepared by commercially available methods or by methods disclosed in the prior art. For example, commercially available raw materials such as tridecyl alcohol polyoxyethylene ether (5EO), tridecyl alcohol polyoxyethylene ether (5EO) polyoxypropylene (2PO), decaalkyl alcohol polyoxyethylene ether (3EO), decaalkyl alcohol polyoxyethylene ether (3EO), and dodecyl alcohol polyoxyethylene ether (5EO) are purchased from BASF and prepared according to the method in CN103540304B. The corresponding tridecyl alcohol polyoxyethylene ether (5EO) sulfonate, tridecyl alcohol polyoxyethylene ether (5EO) polyoxypropylene (2PO) sulfonate, decaalkyl alcohol polyoxyethylene ether (3EO) carboxylate, decaalkyl alcohol polyoxyethylene ether (3EO) carboxylate, and dodecyl alcohol polyoxyethylene ether (5EO) carboxylate are prepared according to the method in CN103540304B.

[0027] According to the present invention, the molar ratio of the bio-based cationic surfactant to the anionic-nonionic surfactant can be selected within a wide range. In a preferred embodiment of the present invention, the molar ratio of the bio-based cationic surfactant to the anionic-nonionic surfactant is 1:(0.01-100); preferably 1:(0.1-10). For example, it can be a ratio of 1 to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or a ratio of 1 to any value or any range of two values ​​between 0.1 and 10.

[0028] A second aspect of the present invention is to provide a method for preparing the composite surfactant described in the first aspect, comprising mixing the bio-based cationic surfactant with the anionic surfactant and / or nonionic surfactant.

[0029] A third aspect of the present invention is to provide an oil displacement composition comprising the composite surfactant and polymer described in the first aspect.

[0030] According to the present invention, the mass ratio of the composite surfactant to the polymer can be selected within a wide range. In a preferred embodiment of the present invention, the mass ratio of the composite surfactant to the polymer is 1:(0.1-1), preferably 1:(0.1-0.5).

[0031] According to the present invention, the polymer can be selected from a wide range. In a preferred embodiment of the present invention, the polymer is selected from water-soluble polymers, preferably from at least one of water-soluble polyacrylamide, acrylate, xanthocyanin, cellulose ether compounds, and polyvinylpyrrolidone.

[0032] A fourth aspect of the present invention is to provide an oil displacement agent comprising the composite surfactant described in the first aspect or the oil displacement composition described in the third aspect, and water.

[0033] According to the present invention, the mass ratio of the composite surfactant to water in the oil displacement agent can be selected within a wide range. In a preferred embodiment of the present invention, the mass ratio of the composite surfactant to water in the oil displacement agent is not greater than 10:100. Preferably, the mass ratio of the composite surfactant to water is not greater than 1:100. More preferably, the mass ratio of the composite surfactant to water is 0.05-0.3:100.

[0034] According to the present invention, the range of suitable mineralization for the above-mentioned composite surfactant and oil displacement composition is relatively wide. In a preferred embodiment of the present invention, the mineralization of the water is 0-25 wt%.

[0035] A fifth aspect of the invention is to provide the application of the composite surfactant according to the first aspect, or the oil displacement composition according to the third aspect, or the oil displacement agent according to the fourth aspect in oilfield development. Application in heavy oil reservoir development is preferred, but not limited thereto.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] (1) This invention provides a novel cationic surfactant. The composite surfactant obtained by compounding the novel cationic surfactant is an anionic-ionic compound composition, which greatly reduces the critical micelle concentration and improves the oil displacement efficiency of the composition.

[0038] (2) The oil displacement agent provided by the present invention can ensure the solubilizing performance and interfacial performance of the surfactant at a low concentration, and can further improve the oil displacement efficiency.

[0039] (3) The composite surfactant and polymer of the present invention have good compatibility. The oil displacement composition obtained in the presence of polymer can greatly increase the oil recovery rate.

[0040] The inventors of this invention believe, after research, that the reasons for the above advantages may be as follows:

[0041] Therefore, using rosin as a hydrophobic group and introducing hydrophilic groups such as amino and alkoxy groups to design and synthesize novel cationic surfactants to improve their surface activity, and further improve the surface activity of composite surfactants compounded with anionic and nonionic surfactants, is an important research topic for improving oil displacement efficiency.

[0042] While existing cationic-anionic surfactant blends can significantly reduce the critical micelle concentration (CMC), research results indicate that the CMC of existing cationic surfactants is much higher than that of anionic-nonionic surfactants, limiting further reductions in the CMC of the blended system. The composite surfactant of this invention is also a cationic-anionic blend, but the cationic surfactant is a cationic surfactant containing rosin or dehydrorosin groups and alkyl polyethers, which significantly reduces the CMC and improves the oil displacement efficiency of the composition. This cationic surfactant has a rosin structure and high affinity; its hydrophilicity can be adjusted by the degree of polymerization of the alkyl polyether, greatly improving its compatibility with heavy oils. When blended with alkyl alcohol anionic-nonionic surfactants, it not only achieves ultra-high interfacial activity but also further reduces environmental impact by avoiding the use of alkylphenol products. Detailed Implementation

[0043] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0044] 1. The testing method and equipment used in the testing of this invention are as follows:

[0045] (1) The method for determining the oil-water interfacial tension was the American TX-500C rotating drop interfacial tension meter.

[0046] (2) Core damage rate determination is obtained by measuring the permeability change before and after core damage using a core displacement device.

[0047] (3) The method for determining the solubility parameter is as follows:

[0048] Phase experiments were primarily conducted using the glass capillary method. A certain amount of surfactant solution and crude oil were added sequentially to a sealed capillary tube at a water-to-oil ratio (WOR) of 1:1. The liquid levels of the surfactant solution and crude oil, as well as their respective masses, were recorded. The glass capillary tube was then sealed with an oxyacetylene flame or epoxy resin and immersed in a 10 mL oil bath glass test tube filled with silicone oil. This test tube was then placed in a metal bath (Hanuo Instruments) and heated at a reservoir temperature of 52°C. The test tube was first manually or mechanically shaken to ensure uniform mixing of the oil and water phases. It was then equilibrated in the constant-temperature metal bath for several days to weeks until the oil-water levels no longer changed. The solubilization parameters (SP) of the oil and water phases could be calculated based on the changes in the oil-water interface levels within the microemulsion.

[0049]

[0050] Where V i V is the volume of the aqueous or oil phase in a microemulsion. s It refers to the volume of the surfactant. The calculation of the SP parameter is based on three assumptions: the total volume remains constant after the oil and water are mixed; all surfactants are in the microemulsion phase; and the volume of the surfactant is equal to its mass.

[0051] (4) The method for determining the wash oil ratio includes the following steps:

[0052] 1) Preparation of standard oil solution

[0053] Weigh 0.5 g (accurate to 0.0001 g) of artificial oil stains and transfer them to a 100 mL volumetric flask. Dissolve the oil stains in petroleum ether with a boiling range of 60℃-90℃ and dilute to the mark. The oil concentration of this solution is 5.0 mg / mL.

[0054] 2) Plotting the standard curve

[0055] Use a pipette to transfer 0.0 mL, 0.2 mL, 0.4 mL, 0.6 mL, 0.8 mL, 1.0 mL, 1.2 mL, and 1.4 mL of standard oil solution into eight clean 50 mL volumetric flasks. Dilute to the mark with petroleum ether with a boiling range of 90℃-120℃. Use petroleum ether with a boiling range of 90℃-120℃ as a blank. Measure the absorbance at a wavelength of 225 nm using a 1 cm cuvette on a spectrophotometer. Plot a standard curve based on the measured absorbance values ​​and the corresponding oil content.

[0056] 3) Preparation of oil sands

[0057] Weigh 3.675g of crude oil into a 250mL beaker, add 10mL of petroleum ether with a boiling range of 60℃-90℃ to dissolve the artificial oil stains, add 156.260g of quartz sand to the solution, stir evenly to fully mix the sand and oil stains, heat and stir in a water bath at 80℃-90℃ for more than 0.5h, evaporate the petroleum ether to obtain oil sand.

[0058] 4) Sample preparation

[0059] Prepare distilled aqueous solutions with mass fractions of 0.3% and 1% for use.

[0060] 5) Weigh 3.0g of oil sand into a 50mL blue-capped bottle, add 10mL of the prepared sample, place the blue-capped bottle in a 60℃ constant temperature water bath, remove the blue-capped bottle every 15 minutes and gently rotate it 10 times, then place it back in the water bath, and leave it for a total of 1 hour. After removing it and shaking it, place it on a colorimetric rack. Carefully pour off the washing solution.

[0061] 6) Rinse the blue-capped bottle with distilled water to remove any remaining cleaning solution until the rinse solution is clear.

[0062] 7) Place the rinsed blue-capped bottle containing oil sand into an oven at (105±1)℃ and dry for 4 hours. Remove it and place it in a desiccator to cool to room temperature.

[0063] 8) Add 50 mL of petroleum ether with a boiling range of 90℃-120℃ to the blue-capped bottle and shake thoroughly. Pipette the petroleum ether solution and measure the absorbance on a spectrophotometer. Determine the residual oil content in the blue-capped bottle from the standard curve.

[0064] 9) Calculation of wash oil ratio

[0065] The wash-oil ratio is calculated using the following formula:

[0066]

[0067] In the formula: X - oil washing rate; K - mass fraction of oil in the oil sand, %; W0 - mass of the oil sand, g; W1 - residual oil content of the oil sand in the blue cap bottle, g.

[0068] (5) The critical micelle concentration was determined by using a Kruss 100 surface tension meter and the drop plate method to measure the surface tension of the surfactant in water at room temperature as a function of concentration, and the CMC value of the surfactant was obtained.

[0069] (6) Core displacement experiments and enhanced oil recovery:

[0070] In this embodiment, homogeneous artificial strip cores (2.5 × 2.5 × 30 cm) were used for core displacement tests. The core porosity was 25%, and the permeability was 650 md. The core was first saturated with formation water and then displaced with crude oil. Afterward, maximum oil saturation was obtained by exchanging the injection and outlet ends until no replacement brine was observed in the produced fluid. The initial oil content in the core was obtained based on the core weight change. The core was then aged for 10 days at reservoir temperature. The fluid injection rate was 0.1 mL / min. The injection sequence was as follows:

[0071] Waterflooding: Inject formation brine until no crude oil is found in the produced water. The waterflood recovery rate is calculated based on the ratio of the amount of crude oil displaced to the initial oil content.

[0072] Chemical flooding: 0.5 pore volume (PV) of SP was injected. The SP consisted of 0.2 wt% surfactant mixture and 0.10 wt% polyacrylamide.

[0073] Post-waterflooding: Water is reinjected until no crude oil is found in the outflow. The final recovery rate is obtained based on the ratio of the total amount of crude oil displaced to the initial oil content.

[0074] The difference between the final recovery rate and the waterflood recovery rate is the chemical flooding enhanced oil recovery rate.

[0075] 2. Source of raw materials for this invention

[0076] All reagent raw materials used in the embodiments of the present invention can be obtained by commercial use or by preparation methods disclosed in the prior art. For example, the raw materials tridecyl alcohol polyoxyethylene ether (5EO), tridecyl alcohol polyoxyethylene ether (5EO) polyoxypropylene (2PO), decaalkyl alcohol polyoxyethylene ether (3EO), decaalkyl alcohol polyoxyethylene ether (3EO), and dodecyl alcohol polyoxyethylene ether (5EO) are purchased from BASF. The corresponding tridecyl alcohol polyoxyethylene ether (5EO) sulfonate, tridecyl alcohol polyoxyethylene ether (5EO) polyoxypropylene (2PO) sulfonate, decaalkyl alcohol polyoxyethylene ether (3EO) carboxylate, decaalkyl alcohol polyoxyethylene ether (3EO) carboxylate, dodecyl alcohol polyoxyethylene ether (5EO) carboxylate, dehydrorosin amine or rosin amine are prepared according to the method in CN103540304B.

[0077] Examples 1-3 and Comparative Examples 1-2

[0078] Preparation of oil displacement agent composition

[0079] The cationic surfactant shown in formula (1) and the cationic surfactant in the prior art were mixed with tridecyl alcohol polyoxyethylene ether (5EO) polyoxypropylene (2PO) sulfonate at a molar ratio of 0.1:1 to obtain a composite surfactant, which was then dissolved in a deionized aqueous solution at 20°C to obtain an oil displacement agent composition with a composite surfactant mass concentration of 0.3wt%.

[0080] Critical micelle concentration (CMC) was measured at 20°C for both the single cationic surfactant and the composite surfactant in the oil displacement agent obtained in this example. The test results are shown in Table 1, indicating that the cationic surfactant provided in this example has an extremely low critical micelle concentration, further reducing the critical micelle concentration of the compound system.

[0081] Table 1

[0082]

[0083]

[0084] Examples 4-6 and Comparative Example 2

[0085] The cationic surfactant shown in formula (1) was mixed with tridecyl alcohol polyoxyethylene ether (5EO) polyoxypropylene (2PO) sulfonate at a molar ratio of 0.25:1 and dissolved in 1% NaCl aqueous solution at 20°C to obtain an oil displacement agent composition with a mass concentration of 0.2wt%.

[0086] The properties of the composite surfactant with Shengli crude oil at 90℃ are shown in Table 2. The results show that the composite surfactant of the present invention can improve the compatibilization parameters, reduce the oil-water interfacial tension, and improve the oil washing rate in oil displacement applications.

[0087] In particular, the cationic polyoxyethylene ether (4EO) dimethyl dehydrochlorinated rosin amine exhibits better solubilizing and interfacial properties for the crude oil in this block. In contrast, the traditional hexadecyl dimethyl benzyl ammonium chloride performs poorly.

[0088] Table 2

[0089]

[0090]

[0091] Examples 7-9 and Comparative Example 3

[0092] The cationic surfactant shown in formula (2) was mixed with decaalkyl alcohol polyoxyethylene ether (3EO) carboxylate at a molar ratio of 0.3:1 to obtain a composite surfactant, which was then dissolved in 0.8% NaCl aqueous solution at 20°C to obtain an oil displacement agent composition with a composite surfactant mass concentration of 0.2wt%.

[0093] The properties of the composite surfactant for oil displacement at 60℃ with crude oil from Xiaermen, Henan Province are shown in Table 3. The results indicate that the composite surfactant of this invention can improve the compatibilization parameters, reduce the oil-water interfacial tension, and increase the oil washing rate in oil displacement applications. In particular, the cationic surfactant, polyoxyethylene ether (2EO) dimethyl rosinamine chloride, exhibits better solubilization and interfacial properties for the crude oil in this block.

[0094] Table 3

[0095]

[0096]

Example 10

[0097] The polyoxyethylene ether (2EO) dimethyl rosin ammonium chloride and decaalkyl alcohol polyoxyethylene ether (3EO) carboxylate shown in Example 7 were mixed at a molar ratio of 0.3:1 to obtain a composite surfactant. This composite surfactant was then compounded with polymeric polyacrylamide at a mass ratio of 1:0.1 and dissolved in a 0.8% NaCl aqueous solution at 20°C to obtain an oil displacement agent composition with a composite surfactant mass concentration of 0.2 wt%. The compatibilization parameter of this oil displacement composition was measured to be 19.8, and the oil-water interfacial tension was 1.2 × 10⁻⁶. -4 mN / m, oil washing rate 63%. This result shows that the surface surfactant and polymer are compounded to slightly improve the solubilization performance and oil washing effect, and the surface surfactant has good compatibility with the polymer.

[0098] The specific parameters of Henan Xiaermen crude oil and Shengli crude oil used in the above embodiments are shown in Table 4.

[0099] Table 4

[0100] <![CDATA[Crude oil density (g / cm 3 )]]> 0.919 0.877 Ground viscosity (mPa·s) 84 26.7 Freezing point (°C) 27 35 Wax content (%) 17.5 22.2 Asphaltene (%) 24.53 21.5

[0101] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

[0102] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0103] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0104] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values; such ranges or values ​​should be understood to include values ​​close to them. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In principle, various technical solutions can be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0105] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

[0106] Furthermore, any implementation described herein can be freely combined with one or more other implementations described herein, and the resulting technical solutions or technical ideas shall be regarded as part of the original disclosure or original record of the present invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination to be obviously unreasonable.

Claims

1. A composite surfactant comprising a bio-based cationic surfactant and an anionic-nonionic surfactant, said bio-based cationic surfactant containing a compound as shown in formula (1) and / or a compound as shown in formula (2): Equation (1); Equation (2); In formulas (1) and (2), R2, R3, and R4 are each independently selected from at least one of hydrogen, C1-C4 alkyl groups, and -Poly-OH, and at least one of R2, R3, and R4 is -Poly-OH; wherein -Poly- is selected from -(PO). m1 -、-(EO) m2 -、-(BO) m3 - at least one of the following, wherein m1, m2, and m3 are each 0 to 20; and m1+m2+m3 is 2-50; X - It is an anion; The anionic-nonionic surfactant is a fatty alcohol polyoxyethylene / polyoxypropylene ether carboxylate and / or a fatty alcohol polyoxyethylene ether / polyoxypropylene ether sulfonate.

2. The composite surfactant according to claim 1, characterized in that: X - It is a halide ion.

3. The composite surfactant according to claim 1, characterized in that: X - For Cl - and / or Br - .

4. The composite surfactant according to claim 1, characterized in that: -Poly- is selected from-(PO) m1 -、-(EO) m2 -、-(BO) m3 - at least one of the following, wherein m1+m2+m3 is 2-20.

5. The composite surfactant according to claim 1, characterized in that: Two of R2, R3, and R4 are independently C1 to C4 alkyl groups, one of which is -Poly-OH, and -Poly- is selected from -(PO). m1 -、-(EO) m2 -、-(BO) m3 - at least one of the following, wherein m1+m2+m3 is 2-50.

6. The composite surfactant according to claim 5, characterized in that: m1+m2+m3 is 2-20.

7. The composite surfactant according to claim 1, characterized in that: The anionic-nonionic surfactant is selected from at least one of tridecyl alcohol polyoxyethylene ether (5EO) sulfonate, tridecyl alcohol polyoxyethylene ether (5EO) polyoxypropylene (2PO) sulfonate, decaalkyl alcohol polyoxyethylene ether (3EO) carboxylate, decaalkyl alcohol polyoxyethylene ether (3EO) carboxylate, and dodecyl alcohol polyoxyethylene ether (5EO) carboxylate.

8. The composite surfactant according to claim 1, characterized in that: The molar ratio of the bio-based cationic surfactant to the anionic-nonionic surfactant is 1: (0.01-100).

9. The composite surfactant according to claim 1, characterized in that: The molar ratio of the bio-based cationic surfactant to the anionic-nonionic surfactant is 1:(0.1-10).

10. A method for preparing a composite surfactant according to any one of claims 1-9, comprising mixing the bio-based cationic surfactant with the anionic-nonionic surfactant.

11. An oil displacement composition comprising the composite surfactant and polymer as described in any one of claims 1-9.

12. The oil displacement composition according to claim 11, characterized in that: The mass ratio of the composite surfactant to the polymer is 1:(0.1-1); and / or, The polymer is selected from water-soluble polymers.

13. The oil displacement composition according to claim 11, characterized in that: The mass ratio of the composite surfactant to the polymer is 1:(0.1-0.5); and / or, The polymer is selected from at least one of water-soluble polyacrylamide, acrylate, xanthocyanin, cellulose ether compounds, and polyvinylpyrrolidone.

14. An oil displacement agent comprising a composite surfactant according to any one of claims 1-9 or an oil displacement composition according to any one of claims 11-13, and water.

15. The oil displacement agent according to claim 14, characterized in that: The mass ratio of the composite surfactant to water in the oil displacement agent is not greater than 10:100; and / or, The water has a mineralization of 0-25 wt%.

16. The oil displacement agent according to claim 14, characterized in that: The mass ratio of the composite surfactant to water in the oil displacement agent is no greater than 1:

100.

17. The oil displacement agent according to claim 14, characterized in that: The mass ratio of the composite surfactant to water in the oil displacement agent is 0.05-0.3:

100.

18. The application of the composite surfactant according to any one of claims 1-9, or the oil displacement composition according to any one of claims 11-13, or the oil displacement agent according to any one of claims 14-17 in oilfield development.

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