Binary bio-based temperature-resistant and salt-resistant system constructed based on interaction of surfactants as well as preparation method and application of binary bio-based temperature-resistant and salt-resistant system

Abstract

The invention relates to a binary bio-based temperature-resistant and salt-resistant system constructed on the basis of interaction of surfactants as well as a preparation method and application of the binary bio-based temperature-resistant and salt-resistant system. The binary bio-based temperature-resistant and salt-resistant system comprises a benzyloxy-octadecanoyl sulfonic acid type surfactant and lauroyl diethanolamide in a mass ratio of (1: 9)-(9: 1). Compared with the prior art, the bio-based surfactant is used for replacing other surfactants used in the traditional oil displacement process, the obtained binary compound system can show excellent interface performance in a wide concentration range (0.010%-0.30%) and a proportion (4: 6-9: 1), and the oil-water interfacial tension can be remarkably reduced to an ultralow level (lt); the high-temperature-resistant and high-salt-resistant oil displacement agent prepared by the preparation method disclosed by the invention can bear the high temperature of 120 DEG C under the specific concentration and proportion, the salt resistance is improved to 100g / L from 50g / L, the calcium resistance is improved to 5000mg / L from 500mg / L, and the high-temperature-resistant and high-salt-resistant oil displacement agent has excellent temperature resistance and salt resistance and is expected to be used for a high-temperature and high-salt oil reservoir oil displacement system.

Description

Technical Field

[0001] The present invention relates to the technical field of oil exploitation, in particular to a binary bio-based temperature-resistant and salt-resistant system constructed based on the interaction of surfactants, and a preparation method and application thereof. Background Art

[0002] Chemical flooding technology is one of the important tertiary oil recovery technologies at present, with a significant effect on improving oil recovery. Chemical composite flooding is a tertiary oil recovery technology developed in the 1980s, and the chemical agents involved include three categories: alkali, surfactant, and polymer. Among them, the role of alkali is to react with acidic components in crude oil at the interface, and reduce the interfacial tension by the generated surface active substances; the role of surfactant is to increase the capillary number by reducing the interfacial tension between oil and water, thereby improving the oil washing efficiency; the role of polymer is to increase the viscosity of the aqueous phase and reduce the permeability of the aqueous phase, so as to improve the sweep efficiency by reducing the water-oil mobility ratio. Chemical composite flooding is to exert the synergistic effect among the above three chemical agents to greatly improve the oil displacement efficiency. However, the on-site situation shows that the addition of alkali in composite flooding will bring a series of problems. First is scaling: the alkali agent will generate precipitation with high-valent ions in formation water, resulting in problems such as scaling in the oil production wellbore and formation plugging, seriously affecting the normal production of the oilfield; second, the alkali agent will cause a salt sensitivity effect on the polymer: high-concentration alkali will hinder the relaxation of polymer molecules in water, and then greatly reduce the viscosity of the polymer, thereby reducing the sweep efficiency. On the other hand, the viscosity and action distance of the polymer are greatly affected by temperature, salinity and shear force, and its injectivity is poor in low-permeability oil reservoirs, and it is easy to block pores, causing serious damage to the reservoir, and is not suitable for low-permeability oil reservoirs. Therefore, low-permeability oil reservoirs are more suitable for exploitation by surfactant flooding in chemical flooding.

[0003] Surfactants are widely used in fields such as washing, personal care, pharmaceuticals, bioremediation, and agriculture. At present, most of the surfactants used are petroleum-based surfactants, which are non-renewable and not friendly to the sustainable development of the environment. Bio-based surfactants have become a research hotspot due to their excellent sustainability, biocompatibility and biodegradability. Some bio-based surfactants can achieve ultra-low oil-water interfacial tension under alkali-free conditions, but their adaptability under high-temperature and high-salinity conditions is weak.

[0004] Chinese Patent CN112694882A discloses a low-cost binary composite flooding system for high-temperature and high-salinity oil reservoirs and its preparation method, which includes the following components: 0.15 - 0.3% of micro-crosslinked temperature- and salt-resistant polymer, 0.05 - 0.2% of emulsifying and thickening surfactant, and the balance is tap water. The micro-crosslinked temperature- and salt-resistant polymer includes the following components by weight: 190 - 210 parts of acrylamide, 25 - 30 parts of 2-acrylamido-2-methylpropanesulfonic acid, 7 - 8 parts of N-vinylpyrrolidone, 3 - 4 parts of morpholine amide, 30 - 35 parts of sodium acrylate, and 700 - 750 parts of pure water. However, this patent also has the following problems: 1) The formula is complex; 2) This system can withstand a temperature of 93°C and a salt concentration of 23 g / L, and it cannot be applied to most high-salinity oilfields, so its application range is relatively narrow. Chinese Patent CN116042201A discloses a temperature- and salt-resistant composite flooding agent and its preparation method, which includes the following raw materials by mass: 100 parts of modified montmorillonite aqueous dispersion, 0.2 - 0.4 parts of petroleum sulfonate, 0.05 - 0.15 parts of non-ionic surfactant, and 0.03 - 0.1 parts of stabilizer. However, this patent also has the following problems: 1) The used petroleum sulfonate is non-degradable; 2) This system can withstand a temperature of 70°C and a salt concentration of 5 g / L, and it cannot be applied to most high-salinity oilfields, so its application range is relatively narrow. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies that cannot adapt to high-temperature and high-salinity conditions, etc., and to provide a binary bio-based temperature- and salt-resistant system constructed based on the interaction of surfactants, its preparation method and application.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a binary bio-based temperature- and salt-resistant system, which includes a benzylmethoxy-octadecanoyl sulfonic acid type surfactant and lauric acid diethanolamide with a mass ratio of 1:9 - 9:1.

[0008] Another technical solution of the present invention is to provide a preparation method of the binary bio-based temperature- and salt-resistant system as described in the above technical solution, which includes the following steps:

[0009] S1. Synthesis of lauric acid diethanolamide:

[0010] React methyl laurate, diethanolamine, and KOH at high temperature. After the reaction, add ethyl acetate to dissolve the mixture, wash until the aqueous phase is neutral, and evaporate ethyl acetate to obtain lauric acid diethanolamide;

[0011] S2. Mix the benzylmethoxy-octadecanoyl sulfonic acid type surfactant and lauric acid diethanolamide in proportion to obtain a binary bio-based temperature- and salt-resistant system.

[0012] In some specific embodiments, in step S1, the molar ratio of methyl dodecanoate to diethanolamine is 1:1.8 to 1:2.5.

[0013] In some specific embodiments, in step S1, the mass ratio of methyl dodecanoate to KOH is 1:0.001 to 1:0.002.

[0014] In some specific embodiments, in step S1, the temperature of the high-temperature reaction is 110 to 150 °C, and the reaction time is 3 to 8 h.

[0015] The third technical solution of the present invention is to provide a high-temperature and high-salt ultra-low interfacial tension system, including the binary bio-based temperature-resistant and salt-resistant system as described in one of the above technical solutions and water. The total mass concentration of the binary bio-based temperature-resistant and salt-resistant system is 0.010% to 0.30%.

[0016] In some specific embodiments, the water is sourced from oilfield formation water. When using the oilfield formation water to prepare the binary bio-based temperature-resistant and salt-resistant system, the sodium salt concentration in the high-temperature and high-salt ultra-low interfacial tension system is 0 g / L to 100 g / L, and the calcium salt concentration is 0 mg / L to 5000 mg / L.

[0017] The sodium salt concentration in the high-temperature and high-salt ultra-low interfacial tension system can also be 50 g / L to 100 g / L, and the calcium salt concentration can also be 500 mg / L to 5000 mg / L.

[0018] There is no need to add additional alkali in the high-temperature and high-salt ultra-low interfacial tension system.

[0019] The fourth technical solution of the present invention is to provide an application of the high-temperature and high-salt ultra-low interfacial tension system as described in the third technical solution above. The high-temperature and high-salt ultra-low interfacial tension system is used for oil exploitation.

[0020] In some specific embodiments, the volume ratio of the high-temperature and high-salt ultra-low interfacial tension system to the oil sample is (1.5 to 2.5)×10 3 :1.

[0021] In some specific embodiments, when the high-temperature and high-salt ultra-low interfacial tension system is used for oil exploitation, the temperature is 45 to 120 °C.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention uses bio-based surfactants to replace other surfactants used in the traditional oil displacement process. The raw materials of the two bio-based surfactants, benzyl-oxy-octadecanoyl sulfonic acid type and lauric acid diethanolamide, prepared can be extracted from renewable biomass, and the products are easily degradable and have low toxicity.

[0024] (2) When the total addition content of the binary system of the present invention is 0.050%, and the mass ratio of benzyl methoxy - octadecanoyl sulfonic acid type to lauric acid diethanolamide is 6:4 or 4:6, it can still maintain an ultra - low interfacial tension (<10 -2 mN / m) at 120°C. When the total addition content of the binary system is 0.30%, and the mass ratio of benzyl methoxy - octadecanoyl sulfonic acid type to lauric acid diethanolamide is 9:1, the interfacial tension of the system is still at an ultra - low level (<10 -2 mN / m) under the condition of 100 g / L NaCl. When the total addition content of the binary system is 0.30%, and the mass ratio of benzyl methoxy - octadecanoyl sulfonic acid type to lauric acid diethanolamide is 8:2, the interfacial tension of the system is still at an ultra - low level (<10 2+ under the condition of 5000 mg / L Ca -2 mN / m). It can be seen that the binary system prepared by the present invention can exhibit excellent interfacial properties within a relatively wide concentration range (0.010% - 0.30%) and ratio range (4:6 - 9:1). Especially within the concentration range of 0.050% - 0.30% and the ratio range of 6:4 - 9:1, it can withstand a high temperature of 120°C, the salt tolerance is increased from 50 g / L to 100 g / L, and the calcium tolerance is increased from 500 mg / L to 5000 mg / L. The binary system prepared by the present invention has excellent interfacial activity under alkali - free conditions, and can also reach an ultra - low interfacial tension at high temperature and high salinity, with excellent temperature resistance and salt resistance properties, and is expected to be used in the oil displacement system for high - temperature and high - salinity oil reservoirs. Description of the Drawings

[0025] Figure 1 It is the liquid chromatography diagram of benzyl methoxy - octadecanoyl sulfonic acid type surfactant.

[0026] Figure 2 It is the positive ion mass spectrometry diagram of benzyl methoxy - octadecanoyl sulfonic acid type surfactant with a retention time of 35.0 min.

[0027] Figure 3 It is the negative ion mass spectrometry diagram of benzyl methoxy - octadecanoyl sulfonic acid type surfactant with a retention time of 35.0 min.

[0028] Figure 4 It is the liquid chromatography diagram of lauric acid diethanolamide.

[0029] Figure 5 It is the positive ion mass spectrometry diagram of lauric acid diethanolamide with a retention time of 20.2 min.

[0030] Figure 6 It is the equilibrium interfacial tension (45°C) between the SPBOPA / LDEA system and crude oil at different concentrations and ratios. Detailed Embodiments

[0031] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and gives detailed implementation manners and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0032] In the following embodiments, unless otherwise specified for raw materials or processing techniques, it means that they are all conventional commercially available raw material products or conventional processing techniques in the art.

[0033] Example 1

[0034] This embodiment provides a preparation method of lauric acid diethanolamide, which includes the following steps:

[0035] 20.0 g of methyl laurate, 19.6 g of diethanolamine (the molar ratio of methyl laurate to diethanolamine is 1:2), and 0.0200 g of KOH (KOH accounts for 0.100% of the weight of methyl laurate) are respectively added into a 250 mL round-bottom flask, and reacted at 140 °C for 6 h to obtain a light yellow viscous liquid. The reaction mixture is fully dissolved by adding 40.0 mL of ethyl acetate solution, and then deionized water is added to wash the organic phase until the aqueous phase is neutral. The washed organic phase is collected and the ethyl acetate is evaporated to obtain lauric acid diethanolamide.

[0036] The analysis conditions of the liquid chromatography-mass spectrometry of the product lauric acid diethanolamide are as follows: injection volume 10.0 μL, ultraviolet detection wavelength at 205 nm, flow rate 0.400 mL / min, column oven temperature 30 °C, mobile phase A is methanol (containing 0.10% formic acid), and B is ultrapure water (containing 0.10% formic acid). Gradient conditions: 0 - 8 min, 80% methanol, 28 min, 100% methanol, 28 - 100 min, 100% methanol.

[0037] The liquid chromatogram of the product lauric acid diethanolamide is as Figure 4 shown, and the positive ion mass spectrum is as Figure 5 shown. The retention time of lauric acid diethanolamide is 20.2 min.

[0038] The preparation method of the benzyloxy-octadecanoyl sulfonic acid type surfactant can refer to CN113930249A.

[0039] This embodiment provides a preparation method of the benzyloxy-octadecanoyl sulfonic acid type surfactant, which includes the following steps:

[0040] 0.0800 mol of anisole and 0.00500 mol of catalyst FeCl are added to 0.0100 mol of oleic acid 3, and stirred and reacted at 65 °C for 6 h to obtain a first intermediate product; 0.0300 mol of 3-dimethylaminopropylamine was added to 10.0 mL of ethylbenzene and mixed evenly, then the first intermediate product was added, and the mixture was stirred and reacted at 160 °C for 5 h, and then the unreacted 3-dimethylaminopropylamine, ethylbenzene and anisole were distilled off to obtain a second intermediate product; 30.0 mL of ethanol and 15.0 mL of water were mixed to prepare an ethanol / water solution, and the second intermediate product, 0.0100 mol of Na 2 CO 3 and 0.0120 mol of 3-chloro-2-hydroxypropanesulfonic acid sodium salt were added, and the mixture was stirred and reacted at 95 °C for 10 h, then ethanol and water were distilled off, and the remaining solid was dissolved in methanol. After separating the methanol phase, methanol was evaporated to dryness to obtain a benzyloxy-octadecanoyl sulfonic acid type surfactant.

[0041] The liquid chromatogram of the product benzyloxy-octadecanoyl sulfonic acid type surfactant is as Figure 1 shown, and the detection conditions are as follows: injection volume 10.0 μL, ultraviolet detection wavelength at 205 nm, flow rate 0.400 mL / min, column oven temperature 30 °C, mobile phase A is methanol (containing 0.10% formic acid), and B is ultrapure water (containing 0.10% formic acid). Gradient conditions: 0 - 8 min, 80% methanol, 28 min, 100% methanol, 28 - 100 min, 100% methanol.

[0042] The positive ion mass spectrum and negative ion mass spectrum of the product benzyloxy-octadecanoyl sulfonic acid type surfactant are respectively as Figures 2 - 3 shown, and the retention time of the benzyloxy-octadecanoyl sulfonic acid type surfactant is 35.0 min.

[0043] A binary bio-based temperature-resistant and salt-resistant system was obtained by mixing benzyloxy-octadecanoyl sulfonic acid type surfactant (SPBOPA) and lauric acid diethanolamide (LDEA) in a mass ratio of 0:10 to 10:0.

[0044] The following performance measurements were carried out on the above-prepared binary bio-based temperature-resistant and salt-resistant system:

[0045] The critical micelle concentration (CMC) and surface tension at CMC in Test Example 1 are shown in Table 1:

[0046] Table 1 CMC, CMC 1 ), CMC mix , and γ ideal of the SPBOPA / LDEA complex system at different mole fractions (X CMC

[0047]

[0048]

[0049] As can be seen from Table 1, the CMC of the system under different molar ratios mix is lower than that of CMC ideal , indicating non-ideal mixing between the two surfactants. In the binary system, when the molar ratio is 8:2 and 6:4, the CMC mix is lower than the CMC of the two single bio-based surfactants. However, regardless of the molar ratio, γ CMC always lies between the values of the two single bio-based surfactants.

[0050] Test Example 2 calculates the interaction parameters of the two surfactants SPBOPA and LDEA in the binary bio-based temperature and salt-resistant system at molar ratios from 2:8 to 8:2. The specific results are shown in Table 2. It can be concluded that there is a synergistic effect between the two surfactants SPBOPA and LDEA, and the synergistic effect is the strongest in the molar ratio range of 6:4 to 8:2.

[0051] Table 2 Interaction composition (X 1 ), interaction parameter (β m ), and activity coefficient (f) of the SPBOPA / LDEA mixed system at 25°C

[0052]

[0053] Test Example 3 measures the oil-water interfacial tension of binary systems with different total mass concentrations and different mass ratios of SPBOPA and LDEA:

[0054] The test temperature is 45°C; the aqueous phase is Daqing simulated formation water with a density of 1.0 g / cm 3 ; the oil sample is the crude oil from the southern eighth district of the Second Oil Production Plant of the Daqing Oilfield with a density of 0.86 g / cm 3 ; the test instrument is a TX-500C type rotating drop interfacial tensiometer. The oil-water ratio is 2 mL of water sample: 1 μL of oil sample, and the measurement is carried out at a rotation speed of 4500 rpm for 2 h.

[0055] The Daqing simulated formation water includes the following components and concentrations: NaCl 1588.3 mg / L, CaCl 2 112.2 mg / L, MgCl 2 42.9 mg / L, Na 2 SO 4 17.1 mg / L, NaHCO 3 3176.0 mg / L, Na 2 CO 3 381.6 mg / L.

[0056] The properties of Daqing crude oil include 68.43% saturated hydrocarbons, 20.01% aromatic hydrocarbons, 10.77% resins, 0.22% asphaltenes, with a total yield of 99.43%, an acid value of 0.82 mgKOH / g, and a viscosity of 976 mPa·s.

[0057] In the following test examples, the same Daqing simulated formation water and Daqing crude oil as above were used.

[0058] The equilibrium interfacial tensions of the SPBOPA / LDEA system with crude oil at different concentrations (0.010% - 0.30%) and ratios (0:10 - 10:0) are as Figure 6 shown, where

[0059] The total content of SPBOPA and LDEA surfactants is 0.30%. The equilibrium interfacial tensions of the binary systems with mass ratios of SPBOPA and LDEA of 10:0, 8:2, 6:4, 4:6, 2:8, 0:10 are 3.1×10 -2 mN / m, 6.3×10 -4 mN / m, 2.0×10 - 3 mN / m, 7.8×10 -3 mN / m, 2.0×10 -2 mN / m, 4.5×10 -2 mN / m.

[0060] The total content of SPBOPA and LDEA surfactants is 0.050%. The equilibrium interfacial tensions of the binary systems with mass ratios of SPBOPA and LDEA of 10:0, 8:2, 6:4, 4:6, 2:8, 0:10 are 1.5×10 -2 mN / m, 9.7×10 -4 mN / m, 9.7×10 - 4 mN / m, 1.4×10 -3 mN / m, 7.8×10 -2 mN / m, 4.3×10 -2 mN / m.

[0061] It can be seen from the above data that, compared with the two single bio-based surfactants, the interfacial tension of the mixed system decreases. When SPBOPA and LDEA are mixed, the concentration range in which the equilibrium interfacial tension (IFTs eq ) can reach an ultra-low level is 0.050% - 0.30%. The lowest IFT eq value reaches 10 -4The order of magnitude is mN / m, indicating that the synergistic effect of the binary system is the strongest at this mass ratio. All the above bio-based surfactant solutions were prepared in Daqing simulated formation water without additional alkali addition. Therefore, an alkali-free ultra-low interfacial tension system can be constructed using SPBOPA and LDEA.

[0062] (4) Measure the temperature resistance of the prepared binary system.

[0063] Prepare simulated formation water solutions with SPBOPA and LDEA concentrations of 0.050% respectively. Mix the SPBOPA simulated formation water solution and the LDEA simulated formation water solution evenly according to the mass ratios of 6:4 and 4:6 to obtain binary systems with a total surfactant (i.e., SPBOPA and LDEA) content of 0.050%, and mass ratios of SPBOPA to LDEA of 6:4 and 4:6.

[0064] Test and characterize the oil-water interfacial tension of the prepared binary system: The test temperature is 120 °C; the aqueous phase is Daqing simulated formation water with a density of 0.95 g / cm 3 ; the oil sample is the crude oil from the southern eighth district of the Second Oil Production Plant of Daqing Oilfield with a density of 0.79 g / cm 3 ; the test instrument is a Krüss SDT high-temperature rotating drop interfacial tensiometer. The oil-water ratio is 2 ml of water sample: 1 μl of oil sample, and measure for 2 h at a rotation speed of 4500 rpm.

[0065] Test temperature: 120 °C. For these two ratios, under the test conditions of 120 °C, the equilibrium interfacial tension can reach ultra-low. The specific results are shown in Table 3, indicating that the system has excellent temperature resistance.

[0066] Table 3 IFT between the binary system and crude oil at 120 °C eq

[0067]

[0068] (5) Measure the NaCl tolerance of the prepared binary system.

[0069] Prepare simulated formation water solutions with SPBOPA and LDEA concentrations of 0.30% respectively. Then mix the SPBOPA simulated formation water solution and the LDEA simulated formation water solution evenly according to the mass ratio of 9:1 to obtain a binary system with a total surfactant (i.e., SPBOPA and LDEA) content of 0.30% and a mass ratio of SPBOPA to LDEA of 9:1.

[0070] Adjust the concentration of NaCl in the water sample to 0 - 120 g / L, and test and characterize the oil-water interfacial tension of the prepared binary system. The test temperature is 45 °C; the oil sample is the crude oil from the southern eighth district of the second oil production plant in Daqing Oilfield, with a density of 0.86 g / cm 3 ; The test instrument is a TX-500C rotary drop interfacial tensiometer. The oil-water ratio is 2 mL of water sample : 1 μL of oil sample, and it is measured for 2 h at a rotation speed of 4500 rpm.

[0071] For the binary system with a total content of 0.30% and a mass ratio of SPBOPA to LDEA of 9:1, under the test conditions of NaCl concentration from 0 to 100 g / L, the equilibrium interfacial tension can reach ultra-low values. The specific results are shown in Table 4, indicating that this system has excellent NaCl tolerance.

[0072] Table 4 Influence of NaCl on IFT between the binary system and crude oil eq Effect

[0073]

[0074] (6) Determine the Ca tolerance of the prepared binary system. 2+ Determination

[0075] Prepare simulated formation aqueous solutions with SPBOPA and LDEA concentrations of 0.30% respectively. Then mix the SPBOPA simulated formation aqueous solution and the LDEA simulated formation aqueous solution evenly according to a mass ratio of 8:2 to obtain a binary system with a total surfactant (i.e., SPBOPA and LDEA) content of 0.30% and a mass ratio of SPBOPA to LDEA of 8:2.

[0076] Adjust the concentration of Ca in the water sample to 0 - 6000 mg / L, and test and characterize the oil-water interfacial tension of the prepared binary system. The test temperature is 45 °C; the oil sample is the crude oil from the southern eighth district of the second oil production plant in Daqing Oilfield, with a density of 0.86 g / cm 2+ ; The test instrument is a TX-500C rotary drop interfacial tensiometer. The oil-water ratio is 2 mL of water sample : 1 μL of oil sample, and it is measured for 2 h at a rotation speed of 4500 rpm. 3 ; The test instrument is a TX-500C rotary drop interfacial tensiometer. The oil-water ratio is 2 mL of water sample : 1 μL of oil sample, and it is measured for 2 h at a rotation speed of 4500 rpm.

[0077] For the binary system with a total content of 0.30% and a mass ratio of SPBOPA to LDEA of 8:2, under the test conditions of Ca concentration from 0 to 5000 mg / L, the equilibrium interfacial tension can reach ultra-low values. The specific results are shown in Table 5, indicating that this system has excellent Ca tolerance. 2+ For the binary system with a total content of 0.30% and a mass ratio of SPBOPA to LDEA of 8:2, under the test conditions of Ca concentration from 0 to 5000 mg / L, the equilibrium interfacial tension can reach ultra-low values. The specific results are shown in Table 5, indicating that this system has excellent Ca tolerance. 2+ tolerance

[0078] Table 5 Influence of Ca on IFT between the binary system and crude oil 2+ Effect eq Effect

[0079]

[0080] (7) Measure the adsorption property of the prepared binary system.

[0081] Prepare simulated formation aqueous solutions with the concentrations of SPBOPA and LDEA being 0.30% respectively. Then, mix the SPBOPA simulated formation aqueous solution and the LDEA simulated formation aqueous solution evenly according to the mass ratio of 8:2 to obtain a binary system with the total content of surfactants (i.e., SPBOPA and LDEA) being 0.30% and the mass ratio of SPBOPA to LDEA being 8:2.

[0082] Seal the surfactant solution and quartz sand with a mesh size of 80 - 120 (quartz sand mass: surfactant aqueous solution mass = 1:9) in a constant temperature shaker at 45°C. After fully shaking for 24 h, take the supernatant to test the interfacial tension. Repeat the above steps until the interfacial tension can no longer be maintained at an ultra - low level.

[0083] The test temperature is 45°C; the water sample is Daqing simulated formation water with a density of 1.0 g / cm 3 ; the oil sample is the crude oil from the southern eighth district of the Second Oil Production Plant of Daqing Oilfield with a density of 0.86 g / cm 3 ; the test instrument is a TX - 500C type rotating drop interfacial tension meter. The ratio of oil to water is 2 mL of water sample: 1 μL of oil sample, and the measurement is carried out at a rotation speed of 4500 rpm for 2 h.

[0084] Test the anti - adsorption property of this binary system. For the binary system with the total content of SPBOPA and LDEA being 0.30% and the mass ratio of SPBOPA to LDEA being 8:2, the equilibrium interfacial tension can still reach an ultra - low level after 8 times of adsorption. The specific results are shown in Table 6, indicating that this system has excellent anti - adsorption property.

[0085] Table 6 IFT between the binary system and crude oil after being adsorbed by quartz sand eq (45°C)

[0086]

[0087]

[0088] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above - mentioned embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A binary bio-based temperature-resistant and salt-resistant system, characterized in that: The invention comprises a benzyloxy-octadecanoyl sulfonic acid type surfactant and lauric acid diethanolamide in a mass ratio of 1:9 to 9:

1.

2. A method for preparing a binary bio-based temperature-resistant and salt-resistant system as claimed in claim 1, characterized in that: The steps include: S1. Synthesis of lauric acid diethanolamide: Methyl dodecanoate, diethanolamine and KOH are reacted at high temperature, ethyl acetate is added to the reaction mixture to dissolve, the mixture is washed until the water phase is neutral, and the ethyl acetate is evaporated to obtain lauric acid diethanolamide; S2. Mix the benzyloxy-octadecanoyl sulfonic acid type surfactant and lauric acid diethanolamide in proportion to obtain a binary bio-based temperature-resistant and salt-resistant system.

3. The preparation method according to claim 2, characterized in that: In step S1, the molar ratio of methyl dodecanoate to diethanolamine is 1:1.8 to 1:2.

5.

4. The preparation method according to claim 2, characterized in that: In step S1, the mass ratio of methyl dodecanoate to KOH is 1:0.001 to 1:0.

002.

5. The preparation method according to claim 2, characterized in that: In step S1, the temperature of the high temperature reaction is 110-150° C., and the reaction time is 3-8 hours.

6. A high temperature, high salt and ultra-low interfacial tension system, characterized in that: It comprises the binary bio-based heat-resistant and salt-resistant system according to claim 1 and water, wherein the total mass concentration of the binary bio-based heat-resistant and salt-resistant system is 0.010% to 0.30%.

7. The high temperature, high salt and ultra-low interfacial tension system according to claim 6, characterized in that: The water comes from oilfield formation water. The binary bio-based temperature-resistant and salt-resistant system is prepared by using the oilfield formation water to obtain a high-temperature, high-salt, ultra-low interfacial tension system in which the sodium salt concentration is 0g / L-100g / L and the calcium salt concentration is 0mg / L-5000mg / L.

8. An application of the high temperature, high salt and ultra-low interfacial tension system as claimed in claim 6 or 7, characterized in that: The high-temperature, high-salt and ultra-low interfacial tension system is used in the field of oil extraction.

9. The use according to claim 8, characterized in that: The volume ratio of the high temperature, high salt and ultra-low interfacial tension system to the oil sample is (1.5-2.5)×10 3 :

1.

10. The use according to claim 8, characterized in that: When the high-temperature, high-salt and ultra-low interfacial tension system is used for oil production, the temperature is 45-120°C.

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