Surfactant composition and fatty alcohol copolymer, preparation method therefor, and use thereof

Abstract

The present invention relates to the field of oil exploitation and oilfield chemical materials, particularly to a fatty alcohol copolymer and a surfactant composition, a preparation method therefor, and a use thereof. The copolymer has a chemical structure represented by formula (1), wherein R is selected from substituted or unsubstituted C14-C70 alkyl and substituted or unsubstituted C14-C70 alkenyl, a substituent for the substitution is selected from at least one of hydroxyl, halogen, cyano, nitro, and amino, x is selected from a positive integer of 20-50, and y is selected from a positive integer of 20-40. In the present invention, the surfactant comprising the fatty alcohol copolymer has the characteristics of good high-temperature resistance and salt resistance and low oil / water interface tension.

Description

Surfactant composition and fatty alcohol copolymer and preparation method and application thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application 202311497678.0 filed on November 11, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the field of petroleum extraction and oilfield chemical materials, and in particular to a surfactant composition and a fatty alcohol copolymer as well as a preparation method and application thereof. Background Art

[0004] Tertiary oil recovery (EOR) is a general term for various new technologies employed after the water flooding stage for different reservoir characteristics. Typical examples include thermal recovery, chemical flooding, gas miscible flooding, and microbial oil recovery. Chemical flooding is one of the most widely studied technologies within EOR, and includes alkaline water flooding, polymer flooding, surfactant flooding, alkali / surfactant / polymer (ASP) ternary flooding, and foam flooding. Surfactant-based flooding has become the mainstream. Commonly used surfactants both domestically and internationally include anionic surfactants (such as alcohol polyoxyethylene ether sulfates (AES), petroleum sulfonates, petroleum carboxylates, and sodium alkylbenzene sulfonates), cationic surfactants (such as cetyltrimethylammonium bromide (CTAB)), nonionic surfactants (such as alkyl polyglycosides (APGs), alkylphenol polyoxyethylene ethers, and Peregal surfactants), zwitterionic surfactants (such as alkyl sulfobetaines), Gemini surfactants (such as sodium xylene didodecyl phosphate), and natural (bio) surfactants (such as rhamnosyl esters, trehalose esters, sophoroside esters, saponins, and rosins). Anionic surfactants have been the most studied, as they exhibit relatively low adsorption losses on negatively charged sandstones. Nonionic surfactants are primarily used as co-surfactants to improve phase behavior and are often used in combination with anionic surfactants. Currently, there are relatively few surfactants with exceptionally low interfacial tension between oil and water, and even fewer meet the requirements of high-temperature, high-salinity reservoirs.

[0005] Therefore, a surfactant composition is needed to make up for the above-mentioned defects of the prior art.

[0006] Summary of the Invention

[0007] The purpose of the present invention is to overcome the problems of poor high temperature resistance and salt resistance and insufficient low oil / water interfacial tension in the prior art, and to provide a surfactant composition and a fatty alcohol copolymer as well as a preparation method and application thereof.

[0008] In order to achieve the above object, the first aspect of the present invention provides a surfactant composition, wherein the composition comprises a fatty alcohol copolymer, inorganic nanoparticles and an anionic surfactant; wherein the fatty alcohol copolymer has a chemical structure shown in formula (1):

[0009] wherein R is selected from substituted or unsubstituted C 14 -C 70 Alkyl, substituted or unsubstituted C 14 -C 70 the substituted substituent is selected from at least one of hydroxyl, halogen, cyano, nitro and amino; x / y=0.6-1.2.

[0010] A second aspect of the present invention provides a method for preparing a surfactant composition, the method comprising:

[0011] mixing a fatty alcohol copolymer, inorganic nanoparticles and an anionic surfactant in a solvent, and optionally adding a solubilizer to obtain the surfactant composition;

[0012] The definitions of the fatty alcohol copolymer, inorganic nanoparticles and anionic surfactant are the same as those described in the first aspect of the present invention.

[0013] The third aspect of the present invention provides use of the surfactant composition described in the first aspect of the present invention in petroleum production and oilfield chemical materials.

[0014] A fourth aspect of the present invention provides a fatty alcohol copolymer, wherein the copolymer has a chemical structure shown in formula (1):

[0015] Wherein, R is selected from C 31 -C 66 The definitions of x and y are the same as those described in the first aspect of the present invention.

[0016] A fifth aspect of the present invention provides a method for preparing a fatty alcohol copolymer, the method comprising:

[0017] (1) contacting fatty alcohol ROH with propylene oxide in the presence of a catalyst and a protective gas to perform a first etherification reaction to obtain a mixture;

[0018] (2) contacting the mixture in step (1) with ethylene oxide, performing a second etherification reaction and performing post-treatment to obtain the fatty alcohol copolymer;

[0019] Wherein, R is selected from C 31 -C 66 of alkyl.

[0020] The sixth aspect of the present invention provides use of the fatty alcohol copolymer described in the fourth aspect of the present invention in a surfactant.

[0021] Through the above technical solution, the present invention provides a surfactant composition, which is a nanoparticle anionic-nonionic composite surfactant. Compared with the prior art, the present invention utilizes inorganic nanoparticles, fatty alcohol copolymers (i.e., fatty alcohol-EO-PO copolymers, nonionic surfactants) and anionic surfactants to prepare nanoparticle anionic-nonionic composite surfactants. The inorganic nanoparticles can not only give the surfactant excellent temperature resistance, but also can synergize with the anionic surfactant to reduce the oil / water surface tension. The nonionic surfactant fatty alcohol copolymer is mainly used as an auxiliary anionic surfactant to improve the phase behavior of the system, thereby increasing the tolerance of the nanoparticle anionic-nonionic composite surfactant to high-salinity formation water. The surfactant composition prepared by the present invention has ultra-low oil / water interfacial tension under high temperature and high salinity conditions, which can increase oil washing efficiency.

[0022] The surfactant composition provided by the present invention exhibits strong temperature and salt resistance. The inorganic nanoparticles can adsorb surfactant molecules on the interfacial film, stabilizing the surfactant molecules at the interface and enhancing their shear resistance. The molecular chains are not easily broken under high temperature conditions, and the system is temperature-resistant to ≥90°C.

[0023] The surfactant composition provided in the present invention has an ultra-low oil / water interfacial tension, the oil / water interfacial tension is ≤10 -4 mN / m. Anionic surfactants are negatively charged and exhibit relatively low adsorption losses on sandstones with negatively charged surfaces. Nonionic surfactant fatty alcohol copolymers are primarily used as auxiliary anionic surfactants to improve the phase behavior of the system, thereby increasing the tolerance of the nanoparticle anionic-nonionic composite surfactant to high-salinity formation water. The surfactant composition prepared by the present invention has a salt tolerance of ≥50,000 mg / L (wherein the Ca and Mg divalent ions are ≥2,000 mg / L). DETAILED DESCRIPTION

[0024] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0025] As mentioned above, the first aspect of the present invention provides a surfactant composition, wherein the composition comprises a fatty alcohol copolymer (nonionic surfactant), inorganic nanoparticles and anionic surfactant; wherein the fatty alcohol copolymer has a chemical structure shown in formula (1):

[0026] wherein R is selected from substituted or unsubstituted C 14 -C 70 Alkyl, substituted or unsubstituted C 14 -C 70 the substituted substituent is selected from at least one of hydroxyl, halogen, cyano, nitro and amino; x / y=0.6-1.2.

[0027] In some embodiments of the present invention, preferably, in formula (1), R is selected from substituted or unsubstituted C 14 -C 68 Alkyl, substituted or unsubstituted C 14 -C 68 Further preferably, R is selected from substituted or unsubstituted C 31 -C 66 Alkyl, substituted or unsubstituted C 31 -C 66 The substituted substituent is selected from at least one of hydroxyl, halogen and cyano, preferably hydroxyl.

[0028] Preferably, x is selected from a positive integer of 20-50; y is selected from a positive integer of 20-40. More preferably, x is selected from a positive integer of 20-45; y is selected from a positive integer of 25-35.

[0029] In some embodiments of the present invention, preferably, x / y=0.8-0.9.

[0030] According to a more preferred embodiment, R is

[0031] In some embodiments of the present invention, preferably, the weight average molecular weight of the copolymer is 2000-4700 g / mol, preferably 2000-4600 g / mol, more preferably 2100-4200 g / mol.

[0032] In some embodiments of the present invention, preferably, the inorganic nanoparticles are selected from at least one of nano-silicon dioxide, nano-aluminum oxide, nano-magnesium carbonate, nano-zinc oxide and nano-titanium oxide, more preferably nano-silicon dioxide and nano-aluminum oxide.

[0033] In some embodiments of the present invention, preferably, the anionic surfactant is selected from at least one of fatty alcohol polyoxyethylene ether sulfate (AES), petroleum sulfonate, petroleum carboxylate, sodium alkyl sulfonate and sodium alkylbenzene sulfonate, more preferably sodium dodecyl sulfonate and / or sodium hexadecylbenzene sulfonate.

[0034] In some embodiments of the present invention, preferably, the mass ratio of the fatty alcohol copolymer to the anionic surfactant is 4:1-1:1, more preferably 2.5:1-1:1.

[0035] In some embodiments of the present invention, preferably, the mass ratio of the fatty alcohol copolymer to the inorganic nanoparticles is 100-800:1, more preferably 700-750:1.

[0036] In the present invention, the surfactant composition may further contain a solubilizing agent. The solubilizing agent may be a common substance that can promote the dissolution of the fatty alcohol copolymer, inorganic nanoparticles, and anionic surfactant in a solvent (such as water), and may be selected from Span. There is no particular requirement for the amount of the solubilizing agent used, but preferably, the mass ratio of the solubilizing agent to the inorganic nanoparticles is 1:0.8-2.5.

[0037] In the present invention, the surfactant composition may further contain a solvent, wherein the solvent is water, preferably deionized water. The content of the solvent is not particularly limited in the present invention. The addition of the solvent can significantly improve the mixing effect of the fatty alcohol copolymer, the inorganic nanoparticles, the anionic surfactant, and the optional solubilizer.

[0038] Further preferably, the total concentration of the fatty alcohol copolymer, inorganic nanoparticles, anionic surfactant and optional solubilizer in the solvent is 0.01-5wt%, preferably 0.1-1wt%, based on the total mass of the fatty alcohol copolymer, inorganic nanoparticles, anionic surfactant and optional solubilizer.

[0039] A second aspect of the present invention provides a method for preparing a surfactant composition, the method comprising:

[0040] mixing a fatty alcohol copolymer, inorganic nanoparticles and an anionic surfactant in a solvent, and optionally adding a solubilizer to obtain the surfactant composition;

[0041] The definitions and usage of the fatty alcohol copolymer, inorganic nanoparticles, anionic surfactant and optional solubilizer are the same as those described in the first aspect of the present invention and will not be repeated here.

[0042] In some embodiments of the present invention, preferably, the solvent is deionized water.

[0043] A third aspect of the present invention provides the use of the surfactant composition described in the first aspect of the present invention in oil production and oilfield chemical materials. The surfactant composition of the present invention can be formulated into a 0.1-1 wt% solution for use or testing. The 0.1-1 wt% concentration refers to the concentration of the fatty alcohol copolymer, inorganic nanoparticles, anionic surfactant, and optional solubilizer in the surfactant composition.

[0044] A fourth aspect of the present invention provides a fatty alcohol copolymer, wherein the copolymer has a chemical structure shown in formula (1):

[0045] Wherein, R is selected from C 31 -C 66 The definitions of R, x and y are the same as those described in the first aspect of the present invention.

[0046] A fifth aspect of the present invention provides a method for preparing a fatty alcohol copolymer, the method comprising:

[0047] (1) contacting fatty alcohol ROH with propylene oxide in the presence of a catalyst and a protective gas to perform a first etherification reaction to obtain a mixture;

[0048] (2) contacting the mixture in step (1) with ethylene oxide, performing a second etherification reaction and performing post-treatment to obtain the fatty alcohol copolymer;

[0049] Wherein, R is selected from C 31 -C 66 wherein the definition of R is the same as that in the first aspect of the present invention.

[0050] In some embodiments of the present invention, preferably, in step (1), the catalyst is selected from at least one of sodium hydroxide, potassium hydroxide and lithium hydroxide, preferably potassium hydroxide.

[0051] In some embodiments of the present invention, preferably, the protective gas is selected from at least one of nitrogen, argon and neon, more preferably nitrogen.

[0052] In some embodiments of the present invention, the fatty alcohol ROH is selected from one or more of 1,2-tetradecanediol (Cas No. 21129-09-9), 1,14-tetradecanediol (Cas No. 19812-64-7), and (6Z)-6-octadecene-1-ol (Cas No. 2774-87-0).

[0053] In some embodiments of the present invention, preferably, the amount of the catalyst used is 1-3 wt % of the mass of the fatty alcohol.

[0054] In some embodiments of the present invention, preferably, the molar ratio of the fatty alcohol to propylene oxide is 1:10-1:55, more preferably 1:12-1:30, and even more preferably 1:20-1:30. Alternatively, the mass ratio of the fatty alcohol to propylene oxide is 35.4:50-120.

[0055] In some embodiments of the present invention, preferably, the temperature of the first etherification reaction is 90-120° C., the pressure is 80-120 Psi, and the time is 2-4 h.

[0056] In some embodiments of the present invention, preferably, in step (2), the molar amount of ethylene oxide added is 0.85-1.6 times the molar amount of propylene oxide added in step (1). Alternatively, the mass ratio of the fatty alcohol to propylene oxide is 35.4:50-120.

[0057] In some embodiments of the present invention, preferably, the temperature of the second etherification reaction is 120-180° C., the pressure is 80-120 Psi, and the time is 2-4 hours.

[0058] In some embodiments of the present invention, preferably, the post-treatment operation includes adjusting the pH to 7-8.

[0059] In some embodiments of the present invention, preferably, the pH value is adjusted by adding an acid; wherein the acid is selected from lactic acid and acetic acid; preferably, lactic acid.

[0060] In some embodiments of the present invention, preferably, the pH value is adjusted to 7-8.

[0061] The sixth aspect of the present invention provides use of the fatty alcohol copolymer described in the fourth aspect of the present invention in a surfactant.

[0062] The present invention is described in detail below through examples. In the following examples, the oil-water interfacial tension parameters were measured using an SVT 25 ultra-low interfacial tension meter; the raw materials, fatty alcohol, inorganic nanoparticles, lactic acid, sodium hexadecylbenzenesulfonate, and sodium dodecylbenzenesulfonate, were analytically pure commercially available from Aladdin Reagent Co., Ltd.; and the raw materials, ethylene oxide and propylene oxide, were chemically pure commercially available from Sinopharm Chemical Reagent Co., Ltd.

[0063] Example 1

[0064] Synthesis of fatty alcohol copolymers:

[0065] In the presence of 0.354 g of potassium hydroxide (catalyst) and nitrogen (protective gas), 35.4 g of (fatty alcohol, Cas No. 21129-09-9) was contacted with 92.8 g of propylene oxide to carry out a first etherification reaction at a reaction temperature of 90° C., a reaction pressure of 80 psi, and a reaction time of 4 h to obtain a mixture;

[0066] The mixture was contacted with 78.88 g of ethylene oxide to conduct a second etherification reaction at a temperature of 120° C., a pressure of 100 psi, and a reaction time of 4 hours. Lactic acid solution was added to adjust the pH to a range of 7-8 to obtain a fatty alcohol copolymer. The fatty alcohol copolymer has the chemical structure shown in formula (1):

[0067] The fatty alcohol copolymer was subjected to nuclear magnetic resonance (NMR) analysis, and the number of ethylene oxide and propylene oxide blocks was calculated by integrated area calculation. Here, x = 20, y = 25, and x / y = 0.8, and the weight-average molecular weight was 2560 g / mol as measured by XPS.

[0068] Preparation of surfactant composition:

[0069] 25 g of the above fatty alcohol copolymer, 0.035 g of inorganic nanoparticles (nanosilica) and 10 g of anionic surfactant (sodium hexadecylbenzenesulfonate) were mixed, 0.035 g of a solubilizer (specifically Span-80) was added, and the mixture was stirred for 1 hour to obtain a surfactant composition.

[0070] Example 2

[0071] Synthesis of fatty alcohol copolymers:

[0072] In the presence of 0.708 g of potassium hydroxide (catalyst) and nitrogen (protective gas), 35.4 g of (fatty alcohol, Cas No. 19812-64-7) was contacted with 116 g of propylene oxide to carry out a first etherification reaction at a reaction temperature of 120° C., a reaction pressure of 120 psi, and a reaction time of 2 h to obtain a mixture;

[0073] The mixture was contacted with 88 g of ethylene oxide to conduct a second etherification reaction at a temperature of 180° C., a pressure of 100 psi, and a reaction time of 4 hours. Lactic acid solution was added to adjust the pH to a range of 7-8 to obtain a fatty alcohol copolymer. The fatty alcohol copolymer has the chemical structure shown in formula (1):

[0074] The fatty alcohol copolymer was subjected to nuclear magnetic resonance (NMR) analysis, and the number of ethylene oxide and propylene oxide blocks was calculated by integrated area calculation. Here, x = 35, y = 35, and x / y = 1, and the weight-average molecular weight was 3800 g / mol as measured by XPS.

[0075] Preparation of surfactant composition:

[0076] 25 g of the above-mentioned fatty alcohol copolymer, 0.15 g of inorganic nanoparticles (nanosilica) and 25 g of anionic surfactant (sodium dodecyl sulfate) were mixed, 0.15 g of a solubilizer (specifically Span-80) was added, and the mixture was stirred for 1 hour to obtain a surfactant composition.

[0077] Example 3

[0078] Synthesis of fatty alcohol copolymers:

[0079] In the presence of 1.06 g of potassium hydroxide (catalyst) and nitrogen (protective gas), 35.4 g of (fatty alcohol, Cas No. 2774-87-0) was contacted with 58 g of propylene oxide to carry out a first etherification reaction at a reaction temperature of 100° C., a reaction pressure of 120 psi, and a reaction time of 2 h to obtain a mixture;

[0080] The mixture was contacted with 70.4 g of ethylene oxide to conduct a second etherification reaction at a temperature of 150° C., a pressure of 120 psi, and a reaction time of 4 hours. Lactic acid solution was added to adjust the pH to a range of 7-8 to obtain a fatty alcohol copolymer. The fatty alcohol copolymer has the chemical structure shown in formula (1):

[0081] The fatty alcohol copolymer was subjected to nuclear magnetic resonance (NMR) analysis, and the number of ethylene oxide and propylene oxide blocks was calculated by integrated area calculation. Here, x = 48, y = 40, and x / y = 1.2. The XPS method determined a weight-average molecular weight of 4700 g / mol.

[0082] Preparation of surfactant composition:

[0083] 24 g of the fatty alcohol copolymer described in Example 3, 0.048 g of inorganic nanoparticles (nano-zinc oxide) and 8 g of anionic surfactant (sodium hexadecylbenzenesulfonate) were mixed, 0.048 g of a solubilizer (specifically Span-80) was added, and the mixture was stirred for 1 hour to obtain the surfactant composition.

[0084] Example 4

[0085] 24 g of the fatty alcohol copolymer prepared in Example 1, 0.15 g of inorganic nanoparticles (nano-zinc oxide) and 6 g of anionic surfactant (sodium hexadecylbenzenesulfonate) were mixed, 0.15 g of a solubilizer (specifically Span-80) and 100 g of water were added, and the mixture was stirred for 1 hour to obtain a surfactant composition.

[0086] Example 5

[0087] 24 g of the fatty alcohol copolymer prepared in Example 2, 0.072 g of inorganic nanoparticles (nano-zinc oxide) and 12 g of anionic surfactant (sodium hexadecylbenzenesulfonate) were mixed, 0.072 g of a solubilizer (specifically Span-80) and 100 g of water were added, and the mixture was stirred for 1 hour to obtain a surfactant composition.

[0088] Example 6

[0089] 24 g of the fatty alcohol copolymer prepared in Example 3, 0.15 g of inorganic nanoparticles (nano-zinc oxide) and 8 g of anionic surfactant (sodium hexadecylbenzenesulfonate) were mixed, 0.072 g of a solubilizer (specifically Span-80) and 100 g of water were added, and the mixture was stirred for 1 hour to obtain a surfactant composition.

[0090] Comparative Example 1

[0091] A surfactant composition was prepared in the same manner as in Example 1, except that the fatty alcohol copolymer and the inorganic nanoparticles were not used, to obtain a reference surfactant composition.

[0092] Comparative Example 2

[0093] A surfactant composition was prepared in the same manner as in Example 1, except that the fatty alcohol copolymer was replaced by isomeric tridecanol polyoxyethylene ether (nonionic surfactant) to obtain a reference surfactant composition.

[0094] Comparative Example 3

[0095] A surfactant composition was prepared in the same manner as in Example 1, except that no inorganic nanoparticles were used, to obtain a reference surfactant composition.

[0096] Comparative Example 4

[0097] A surfactant composition was prepared in the same manner as in Example 1, except that the inorganic nanoparticles and the anionic surfactant were not used, to obtain a reference surfactant composition.

[0098] Test Example 1

[0099] The surfactant compositions prepared in Examples 1-6 were placed in formation water with a salinity of 50,000 mg / L and stirred for 1 hour to prepare 0.1 wt% and 0.5 wt% surfactant composition solutions, respectively. The surfactant composition solutions were filled into a test tube, and a drop of Daqing crude oil was injected. The interfacial tension between the surfactant composition solutions of different concentrations and the Daqing crude oil was measured at 90°C using an SVT 25 ultra-low interfacial tension meter at a speed of 6,000 r / min. The test results are shown in Table 1.

[0100] Table 1

[0101] Test Example 2

[0102] The surfactant composition prepared in Example 1 was used to prepare a series of surfactant composition solutions of varying concentrations using formation water having a salinity of 50,000 mg / L. A test tube was filled with the surfactant composition solution, and a drop of Daqing crude oil was injected. The interfacial tension between the surfactant composition solutions of varying concentrations and the Daqing crude oil was measured at 90°C using an SVT 25 ultra-low interfacial tension meter at a speed of 6,000 r / min. The test results are shown in Table 2.

[0103] Table 2

[0104] Test Example 3

[0105] The surfactant composition prepared in Example 1 and the reference surfactant compositions prepared in Comparative Examples 1-4 were respectively placed in formation water with a salinity of 50,000 mg / L and stirred for 1 hour to prepare a 0.1 wt% test solution. The surfactant composition solution was filled into a test tube, and a drop of Daqing crude oil was injected. The interfacial tension between the surfactant composition solution system and the crude oil was measured at 90°C using an SVT 25 ultra-low interfacial tension meter at a speed of 6,000 r / min. The test results are shown in Table 3.

[0106] Table 3

[0107] As shown in Table 3, the surfactant composition prepared in Example 1 of the technical solution of the present invention has a lower oil-water interfacial tension than the surfactants prepared in Comparative Examples 1-4, with a minimum of 1.05×10 -4 mN / m, with significantly better technical results.

[0108] At the same time, compared with the existing technology (CN112708410A, CN108285781B and literature: Ma Jiangbo, Li Jianxun, Li Gang, etc. Screening and evaluation of surfactant flooding system for low-temperature, high-salinity and low-permeability oil reservoirs [J]. Oilfield Chemistry, 2022, 39(04): 682-687.), the surfactant composition prepared by Examples 1-6 of the technical solution of the present invention can still maintain its oil-water interfacial tension at 10 when the system temperature is ≥90°C. -4 mN / m level, which is not achievable with the existing technology. Therefore, the technical solution of the present invention has significantly better technical effects in terms of temperature resistance.

[0109] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A surfactant composition, characterized in that: The composition comprises a fatty alcohol copolymer, inorganic nanoparticles and an anionic surfactant; wherein the fatty alcohol copolymer has a chemical structure shown in formula (1): wherein R is selected from substituted or unsubstituted C 14 -C 70 Alkyl, substituted or unsubstituted C 14 -C 70 The substituted substituent is selected from at least one of hydroxyl, halogen, cyano, nitro and amino; x / y=0.6-1.

2.

2. The composition according to claim 1, wherein In formula (1), R is selected from substituted or unsubstituted C 14 -C 68 Alkyl, substituted or unsubstituted C 14 -C 68 The substituted substituent is selected from at least one of hydroxyl, halogen and cyano; x is selected from a positive integer of 20-50; y is selected from a positive integer of 20-40; and / or, x / y=0.8-0.9; And / or, the weight average molecular weight of the copolymer is 2000-4600 g / mol.

3. The composition according to claim 1 or 2, wherein The inorganic nanoparticles are selected from at least one of nano silicon dioxide, nano aluminum oxide, nano magnesium carbonate, nano zinc oxide and nano titanium oxide; And / or, the anionic surfactant is selected from at least one of fatty alcohol polyoxyethylene ether sulfate, petroleum sulfonate, petroleum carboxylate, sodium alkyl sulfonate and sodium alkylbenzene sulfonate; And / or, the mass ratio of the fatty alcohol copolymer to the anionic surfactant is 4:1-1:1 And / or, the mass ratio of the fatty alcohol copolymer to the inorganic nanoparticles is 100-800:

1.

4. A method for preparing a surfactant composition, the method comprising: Mixing a fatty alcohol copolymer, inorganic nanoparticles and anionic surfactant in a solvent, and optionally adding a solubilizer to obtain the surfactant composition; Wherein, the fatty alcohol copolymer, inorganic nanoparticles and anionic surfactant are the same as defined in any one of claims 1-3.

5. The method according to claim 4, wherein: The mass ratio of the solubilizer to the inorganic nanoparticles is 1:0.8-2.

5.

6. Use of the surfactant composition according to any one of claims 1 to 3 in petroleum production and oilfield chemical materials.

7. A fatty alcohol copolymer, wherein: The copolymer has a chemical structure shown in formula (1): Where R is selected from C 31 -C 66 The definitions of x and y are the same as those in claim 1 or 2.

8. A method for preparing a fatty alcohol copolymer, the method comprising: (1) contacting fatty alcohol ROH with propylene oxide in the presence of a catalyst and a protective gas to carry out a first etherification reaction to obtain a mixture; (2) contacting the mixture in step (1) with ethylene oxide, performing a second etherification reaction and performing post-treatment to obtain the fatty alcohol copolymer; Where R is selected from C 31 -C 66 of alkyl.

9. The method according to claim 8, wherein: In step (1), the catalyst is selected from at least one of sodium hydroxide, potassium hydroxide and lithium hydroxide; And / or, the protective gas is selected from at least one of nitrogen, argon and neon; and / or, the amount of the catalyst used is 1-3 wt% of the mass of the fatty alcohol; The molar ratio of the fatty alcohol to propylene oxide is 1:10-1:55 by mass; And / or, the temperature of the first etherification reaction is 90-120°C; the pressure is 80-120Psi; and the time is 2-4h; And / or, in step (2), the molar amount of ethylene oxide added is 0.85-1.6 times the molar amount of propylene oxide added in step (1); And / or, the temperature of the second etherification reaction is 130-180°C; the pressure is 80-120Psi; and the time is 2-4h; And / or, the post-treatment operation includes adjusting the pH to 7-8; And / or, the pH value is adjusted by adding acid; wherein the acid is selected from lactic acid and / or acetic acid.

10. Use of the fatty alcohol copolymer according to claim 7 in the preparation of a surfactant.

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