CN112226225A

CN112226225A - Temperature-resistant and salt-resistant surfactant composition for pressure reduction and injection increase of water injection well of low-permeability oil reservoir and preparation method and application thereof

Info

Publication number: CN112226225A
Application number: CN201910633117.6A
Authority: CN
Inventors: 张卫东; 李应成; 鲍新宁; 金军; 孟勇; 吴欣悦
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2019-07-15
Filing date: 2019-07-15
Publication date: 2021-01-15
Anticipated expiration: 2039-07-15
Also published as: CN112226225B

Abstract

The invention relates to a temperature-resistant and salt-resistant surfactant composition for pressure reduction and injection augmentation of a low-permeability reservoir water injection well, a preparation method and application thereof, and mainly solves the problems of high use concentration of a surfactant, narrow interface activity concentration window, low emulsification speed and poor solubilization effect in the prior art, and the surfactant composition comprises an anionic-nonionic surfactant and a cationic-nonionic surfactant, wherein the molar ratio of the anionic-nonionic surfactant to the cationic-nonionic surfactant is (1-100) to (1-100); the structural general formula of the cationic-nonionic surfactant is shown as a formula (I), and the structural general formula of the anionic-nonionic surfactant is shown as a formula (II), so that the problem is solved well, and the cationic-nonionic surfactant can be used in industrial application of reducing pressure and increasing injection in an oil field to improve recovery ratio.

Description

Temperature-resistant and salt-resistant surfactant composition for pressure reduction and injection increase of water injection well of low-permeability oil reservoir and preparation method and application thereof

Technical Field

The invention relates to a surfactant in-situ microemulsion system applicable to depressurization and augmented injection of high-temperature, high-salinity and low-permeability oil reservoir oil-water well in the technical field of oil exploitation and a preparation method thereof

Background

The residual petroleum resource amount in China is 799 hundred million tons, wherein the low-permeability resource amount is 431 hundred million tons, which accounts for 60 percent of the total amount of the residual petroleum resource, and the development potential is huge. However, due to the reasons of poor physical properties of a low-permeability reservoir, complex pore structure, low permeability, fine pore throat, strong Jamin effect, high clay mineral content, serious reservoir sensitivity and the like, the development process always shows that the water injection pressure ratio is higher, a water injection well is difficult to complete injection allocation, water is not injected in a land or even injected, and due to serious shortage of stratum energy, the low-oil extraction speed, the low-extraction degree and the development stage with medium and low water content are mostly adopted, so that the yield-increasing potential is very great.

Factors influencing the water injection of the low-permeability oilfield comprise an external factor and an internal factor, wherein the internal factor is the characteristic of a reservoir, and the external factor mainly comprises the influences of substandard water quality, incompatibility of injected water and formation fluid, large well spacing and water injection speed. In combination with the water injection characteristics of low permeability oil fields, analysis shows that reservoir phase permeability characteristics and water injection quality are main influence factors. Therefore, how to effectively reduce the water injection pressure of the low-permeability water injection well is the key point of the low-permeability oil reservoir development at present and is also a difficult point. The resistance of the low-permeability oil reservoir influencing the water injection starting pressure gradient mainly comprises viscous resistance and capillary resistance. The viscous resistance is influenced by the viscosity of the fluid and the seepage velocity, and the capillary resistance is mainly determined by the oil-water interfacial tension. Therefore, the surfactant can effectively reduce the injection pressure by reducing the oil-water interfacial tension and changing the rock wettability, thereby achieving the purpose of improving the oil well recovery ratio.

The surfactant system for reducing pressure and increasing injection commonly used in oil fields at present is a surfactant active water drive and a nano-particle or nano-particle surfactant composition system, for example, Chinese patent publication No. CN105154051A discloses a surfactant composition for reducing pressure and increasing injectionThe pressure-reducing and injection-increasing surfactant compound composition consists of a zwitterionic surfactant (alkyl amide propyl hydroxysultaine of C12-C18), a clay stabilizer (copolymer organic of epichlorohydrin and dimethylamine), a water-soluble polymer scale inhibitor (maleic acid or a copolymer of maleic anhydride and acrylic acid) and water. The instantaneous oil-water interfacial tension of the pressure-reducing injection-increasing composition is up to 9.4 multiplied by 10 at the reservoir temperature of 53 DEG C^-3mN/m, equilibrium interfacial tension of 10^-2mN/m, the anti-swelling rate can reach 60%, the pressure reduction rate is 15.2-18.8%, and the method can be used for ultra-low permeability and ultra-low permeability oil reservoirs with the volume less than 5 mD; chinese patent publication No. CN105255470A discloses a composite nano-silica pressure-reducing injection-increasing agent and a preparation method thereof, wherein the composite nano-silica pressure-reducing injection-increasing agent consists of nano-silica, an anionic surfactant, a surface modifier and active water, and is characterized by having excellent temperature resistance, good pressure-reducing injection-increasing effect at 120 ℃, simple process and convenient operation, and can effectively inhibit the problems of aperture reduction, throat blockage and the like caused by clay expansion. The Chinese patent CN102502663A utilizes the hydrolysis of silicon tetrachloride to prepare the hydrophobic nano-silica by an in-situ modification method, and has the defect that organic solvents such as carbon tetrachloride, toluene, diesel oil, liquid paraffin and the like are needed to be used for dispersion. Chinese patent CN101205423A utilizes the hydrolysis reaction of silicate ester and sodium silicate to form hydrophobic nano-silica with the particle size of 5-60 nm by an in-situ modification method, and can be used for reducing pressure and increasing injection of low-permeability oil reservoirs. But needs to be dispersed by carbon tetrachloride, toluene, diesel oil, liquid paraffin and other organic solvents, and has high cost and easy environmental pollution. Chinese patent CN10628288A reports that a surfactant mixture for pressure reduction and injection increase, which takes quaternary ammonium salt as a main agent, and fluorocarbon FC-4430, fatty alcohol polyoxyethylene ether, dioctylalkyl dimethyl ammonium chloride, dimethyl ketoxime and ethylene diamine tetramethylene sodium phosphonate, can reduce the water injection pressure by more than 20 percent, greatly improves the water injection effect of a low-permeability reservoir, and simultaneously has the effects of corrosion inhibition, scale inhibition, expansion prevention, sterilization and the like. However, the pressure-reducing injection-increasing agent contains oil, organic fluorine, organic phosphine and other components, which not only has high cost but also causes the problems ofAnd (5) environmental pollution. Chinese patent CN106085401A reports a pressure-reducing and injection-increasing surfactant composition consisting of a nonionic surfactant (fatty alcohol-polyoxyethylene ether or polyoxyethylene ether sorbitan fatty acid ester), an anionic surfactant (and alpha-olefin sulfonate or sodium dodecyl benzene sulfonate or sodium dodecyl sulfonate), a zwitterionic surfactant (cocamidopropyl betaine or tetradecylamidopropyl hydroxyethyl betaine) and nano-silica, and experimental results show that the pressure-reducing and injection-increasing surfactant has better permeability and rock wettability improvement capacity, and is applied to ultra-low permeability reservoirs in a combined mode of acidification and pressure-reducing and injection-increasing agent treatment: the result shows that the injection pressure can be reduced from about 12MPa to about 8MPa and the effective period is longer. But the temperature resistance and salt tolerance of the pressure-reducing injection-increasing agent of the composition are not high according to the structure of the used surfactant. Chinese patent publication No. CN102965091A discloses a pressure-reducing and injection-increasing surfactant composition for ultra-low permeability oil reservoirs, a preparation method and application thereof, wherein the pressure-reducing and injection-increasing surfactant compound composition comprises a gemini cationic surfactant, a nonionic surfactant (lauric acid diethanolamide), an organic phosphonic acid scale inhibitor, an iron ion stabilizer (a compound of hydroxycarboxylic acid and aminocarboxylic acid) and water. The interfacial tension of the pressure-reducing injection-increasing composition can reach 10 at the oil reservoir temperature of 65 DEG C^-3mN/m order of magnitude, the anti-swelling rate can reach 80 percent, and the scale inhibition rate can reach about 85 percent. The results of the indoor evaluation showed that the injection pressure could be reduced from about 1.4MPa to about 0.92 MPa.

According to the results reported in the related patents, the blood pressure reducing and injection increasing agent system cannot be suitable for high temperature of 120 ℃ and high-salt TDS (50000mg/L, Ca)²⁺+Mg²⁺3000mg/L) hypersalinity, low permeability reservoir.

Chinese patent publication No. CN106467732A discloses a pressure-reducing and injection-increasing surfactant system for a high-temperature high-salt low-permeability reservoir, which consists of a composite alkylamido polyoxyethylene ether phosphate surfactant, a disuccinate disulfonate surfactant, a composite organic alcohol substance (C12, C14 and C16 alcohol), an organic anti-swelling agent and water. The temperature resistance and salt reduction resistanceThe surfactant can reduce oil-water interfacial tension by 6 x 10^-3mN/m, residual oil is easy to flow, the Jamin effect at the pore throat of the low permeability rock core is reduced, the fluidity of the oil phase is increased, the oil phase has very good temperature resistance effect, the temperature resistance can reach 130 ℃, the salt tolerance can reach 200000mg/L, the starting pressure of the fluid in the low permeability rock core can be obviously reduced, and the pressure reduction rate can reach more than 25%. However, the 6X 10 described in this patent^-3The ultra-low interfacial tension of mN/m is measured at 70 ℃, the temperature of which is 130 ℃ is measured at 70 ℃ after the pressure-reducing injection-increasing surfactant aqueous solution is placed at 130 ℃ for 24 hours, and the tension is reduced to 8 x 10^-3mN/m, (which can be expected from the formulation containing about 13% bis-succinate bis-sulfonate surfactant), and 200000mg/L salt resistance, which can be predicted from the water solubility and surface tension test results, whether it can reach 10 in 130 ℃, 200000mg/L mineralized water^-3The ultra-low interfacial tension of mN/m is not found.

Therefore, in order to effectively meet the actual requirements of reducing pressure and increasing injection of a high-temperature high-salinity low-permeability oil reservoir to improve the recovery of crude oil and expand the application range of the surfactant product for reducing pressure and increasing injection, a corresponding high-efficiency system for reducing pressure and increasing injection is necessary to be developed.

According to the results of related research and field experiments at home and abroad, in tertiary oil recovery, the microemulsion is used as an oil displacement agent, and a surfactant injected into a stratum is mainly mixed with crude oil and stratum fluid, so that various paraffins, asphaltins, scales and the like can be effectively contacted and dispersed to form a middle-phase microemulsion, the microemulsion has super solubilization performance, and the microemulsion reaches a balanced state with the crude oil and stratum water in the stratum after being formed. At the moment, the tension on two interface films of the microemulsion phase and the water phase and the microemulsion phase and the oil phase reaches an ultralow value, simultaneously, the wettability of the rock surface is changed, the ideal wettability of the rock surface is controlled and maintained, and the capillary pressure is reduced. In addition, the microemulsion liquid drops are extremely small (nano-scale), can quickly and effectively enter rock pores, improves the contact efficiency of the treatment liquid and the surface of the stratum, and can greatly improve the crude oil recovery ratio. And the microemulsion system with reasonable formula has good high temperature resistance and high salt resistance, and can be theoretically suitable for oil reservoirs with any properties: the method can be applied to tertiary oil recovery of various high-temperature high-salinity oil reservoirs, low-permeability ultra-low permeability and heavy oil reservoirs and the like which are difficult to solve by the chemical flooding main body technology mainly formed by polymers at present, and is an advanced oil displacement technology in the existing chemical flooding enhanced recovery technology.

The microemulsion is a thermodynamically stable, isotropic, transparent or semitransparent dispersion system spontaneously generated by hydrocarbon, water, surfactant, cosurfactant, cosolvent, electrolyte and the like, and the particle size is usually between 1 and 100nm, but the microemulsion can also be formed between 1 and 1000 nm. Since the discovery of the microemulsion by the gear and the Schulman in 1943, the research on the microemulsion system in the last 70-80 s has formed a complete theoretical system in aspects of properties, phase states and structures, and the application research of the microemulsion system in the enhanced oil recovery technology has made great progress. For example, Gogarty and Olson applied 1962 a patent to the use of microemulsions in a new miscible-type oil recovery process (US3254714), known as Maraflood (Maraflood)^TmTrademark of marathon oil corporation). In the middle of the 60's, the sulfonate surfactant was used in sequential oil recovery in the United states and the former Soviet Union to carry out microemulsion flooding tests in mines, such as the injection of 5.6X 10 surfactants by Exxon corporation in Loudon oil field in 1983 in 9 months⁷2.3 percent of surfactant and 0.1 percent of xanthan gum, and the recovery rate is improved to 68 percent. The Marathon company injects 10% surfactant into 0.1PV in the Robinson oil field, and the recovery ratio is improved by 19-21%. Proves the technical feasibility and potential application prospect of microemulsion flooding. Since the last 90 s, research development on microemulsion application is faster, U.S. Texas university reports that a branched alcohol polyoxypropylene/polyoxyethylene ether sulfate and a specific cosurfactant system are applied to the microemulsion, the microemulsion can form a microemulsion with ultralow oil-water interfacial tension and low viscosity with crude oil at 100 ℃, 5% of salt content and 1.0-3.0% of concentration range, the solubilization parameter is at least 10, and the indoor displacement result shows that: the ASP + P + Emulsion combined flooding can improve the residual oil recovery rate after water flooding to 94.7 percent. Shell company discloses a C in its application of the invention patent US8940668/CN102449103_15-18Internal olefin sulfonates and different hydrocarbons at temperatureThe microemulsion oil extraction method is carried out in the stratum with the temperature higher than 70 ℃ and the salt content higher than 13 percent. Phase experiment tests of C at 90 DEG C_15-18When the effect of the internal olefin sulfonate and the n-octane is 13.6 percent of the optimal salt content, the solubilization parameter is 9.2, and the interfacial tension is reduced to 0.0035 mN/m; with n-dodecane, the solubilization parameter reached 10 and the surface tension 0.0030mN/m at an optimum salinity of 14.5%. U.S. Stepan company discloses in its application U.S. Pat. No. 5,2014,0073541, C-containing_12-20Polyoxypropylene sulfate salt, C_12-20Internal olefin sulfonates and C_4-12The microemulsion system achieves low tension by using the technology of carrying out microemulsion flooding enhanced oil recovery by using the ethylene glycol ether sulfate composition. In the field application, after the nineties of the last century, 21 surfactant microemulsion flooding projects are developed by the American Oil Chem Tech company globally, and good effects are achieved.

In China, high-concentration surfactant flooding mine field tests are carried out on 322 blocks of elm forest oil field trees and 82-152 blocks of sunward ditch oil field trees at the periphery of Daqing oil field. The mine field test shows that the recovery rate is greatly improved, and the phenomenon of crude oil emulsification, namely microemulsion can be observed in most of the produced liquid of the oil production well. However, the surfactant applied to the existing mine field only starts to form the microemulsion in a high-concentration area, the using concentration of the surfactant is high, generally about 1.5-4%, and the cost is high, so that the application of the microemulsion flooding mine field is limited.

Therefore, for the development of low permeability reservoirs, a low concentration surfactant in-situ microemulsion flooding system is needed to improve

Disclosure of Invention

The invention provides a surfactant composition for depressurization and injection increase of an extra-low permeability reservoir water injection well, which can be used for 120 ℃ high temperature and 7500-90000 mg/L mineralization degree and can form an in-situ microemulsion system with crude oil, and solves the technical problems of poor temperature resistance, salt tolerance, low depressurization and injection increase efficiency and short use period of the existing system for depressurization and injection increase of the low permeability reservoir, in particular to the worldwide technical problem of increasing the recovery ratio by depressurization and injection increase of the extra-low permeability ultra-high temperature and high mineralization reservoir, and the problems of high use concentration of a surfactant, narrow interface activity concentration window, slow emulsification speed and poor solubilization effect in the prior art; the method has the advantages of wide applicable concentration window, high emulsifying speed, good solubilization, high interfacial activity and the like, and is particularly suitable for depressurization and injection enhancement of low-permeability, ultra-high-temperature and high-salinity oil reservoirs to improve the recovery ratio.

The second technical problem to be solved by the present invention is to provide a method for preparing a surfactant composition corresponding to the solution of the first technical problem.

The invention also provides a surfactant composition corresponding to the technical problem to be solved, and the application of the surfactant composition in tertiary oil recovery.

The fourth technical problem to be solved by the present invention is to provide a method for increasing the recovery ratio of crude oil, which uses the surfactant composition described above for solving one of the technical problems.

In order to solve one of the above technical problems, the technical scheme adopted by the invention is as follows: a surfactant composition applicable to depressurization and injection augmentation of a water injection well of a high-temperature and hypersalinity ultra-low-permeability oil reservoir comprises an anionic-nonionic surfactant and a cationic-nonionic surfactant, wherein the molar ratio of the anionic-nonionic surfactant to the cationic-nonionic surfactant is 1 (0.01-100); wherein the structural general formula of the cationic-nonionic surfactant is shown as the formula (I):

the structural general formula of the anionic-nonionic surfactant is shown as a formula (II):

in the formula, R₁Is C₈～C₂₂Aliphatic hydrocarbon radical of R₂、R₃Is independently selected from C₁～C₆P1 and p2 are CH₂The number of chain segments is independently selected from any one of 1 to 6Meaning an integer, X^—An anion or anionic group for charge balancing formula (I); r₄Is C₁～C₃₀The fatty group of (a); n is the sum of ethoxy groups, and n is an integer or decimal of 0-20; m is the sum of propoxy groups, and m is an integer or decimal of 0-20; q is CH₂The number of chain segments is selected from any integer of 1-6; y is selected from-COO^—、-SO₃ ^—At least one of; m is a cation or cationic group that maintains charge balance in formula (II).

In the technical scheme, R in the structural general formula of the cationic-nonionic surfactant₁Preferably C₁₂～C₂₂Alkyl of R₂、R₃Independently is preferably C₁～C₄P1 and p2 are independently selected to be any integer of 1-4, p1 is more preferably 3, and p2 is more preferably any integer of 2-4; x^—Is preferably-Cl^—、-Br^—、-I^—Or CH₃COO^-、NO₃ ^-More preferably-Cl^—、-Br^—Most preferred is-Cl^—(ii) a M is preferably an ammonium ion or a monovalent metal ion, more preferably an ammonium ion or a monovalent alkali metal cation, and most preferably an ammonium ion, a sodium ion or a potassium ion.

In the technical scheme, in the structural general formula of the anionic-nonionic surfactant, R is₄Preferably C₂～C₂₂More preferably C₂～C₂₂Is more preferably C₂～C₂₂Most preferably C₈～C₁₅Alkyl groups of (a); q is preferably any one integer of 1 to 4, more preferably any one integer of 2 to 3, and most preferably 2; n is an integer or decimal number preferably ranging from 2 to 10; m is preferably an integer or decimal of 2 to 10.

In the technical scheme, the mole ratio of the cationic-nonionic surfactant to the anionic-nonionic surfactant is 1 (0.1-10).

To solve the second technical problem, the invention adopts the following technical scheme: a preparation method of a surfactant composition for reducing blood pressure and increasing injection comprises the following steps:

uniformly mixing an anionic-nonionic surfactant and a cationic-nonionic surfactant with optional water according to a molar ratio of 1 (0.1-100) to obtain the surfactant composition;

wherein the structural general formula of the cationic-nonionic surfactant is shown as the formula (I):

in the formula, R₁Is C₈～C₂₂Aliphatic hydrocarbon radical of R₂、R₃Is independently selected from C₁～C₆P1 and p2 are CH₂The number of chain segments is independently selected from any integer of 1-6, X^—An anion or anionic group for charge balancing formula (I); r₄Is C₁～C₃₀The fatty group of (a); n is the sum of ethoxy groups, and n is an integer or decimal of 0-20; m is the sum of propoxy groups, and m is an integer or decimal of 0-20; q is CH₂The number of chain segments is selected from any integer of 1-6; y is selected from-COO^—、-SO₃ ^—At least one of; m is a cation or cationic group that maintains charge balance in formula (II).

In the above technical solution, the preparation method of the anionic-nonionic surfactant is preferably:

1) will be provided with

In the presence of catalyst A according to

The mol ratio of the epoxypropane to the epoxyethane is 1 (0-20) to (0-20), and the epoxypropane and the epoxyethane are sequentially subjected to alkoxylation reaction to obtain the epoxy propane/epoxyethane mixture

2) Will be provided with

In the presence of a catalyst B, carrying out carboxylation or sulfonation reaction with a carboxylating agent or a sulfonating agent, and carrying out post-treatment to obtain the anionic-nonionic surfactant; wherein, according to the molar ratio,

the catalyst B comprises (1-4) a carboxylating agent or a sulfonating agent and (1-4).

In the technical scheme, the reaction temperature of the alkoxylation reaction is preferably 100-200 ℃, and the reaction time is preferably 1-5 hours; the carboxylation or sulfonation reaction is preferably carried out in an organic solvent, the reaction temperature is preferably 50-100 ℃, the reaction time is preferably 2-10 hours, and the organic solvent is preferably common organic solvents such as benzene, toluene and the like; the catalyst A and the catalyst B are independently and preferably selected from alkali metal hydroxides, and are more independently and preferably selected from one of sodium hydroxide or potassium hydroxide; the carboxylating or sulfonating agent is preferably

Wherein X₀Is a halogen substituent, M₀Is H⁺Ammonium ions or metal ions; y is preferably a sulfonate or carboxylate; the post-treatment may be a post-treatment method commonly used in the art, such as pH adjustment by addition of hydrochloric acid<And 3, carrying out oil-water separation, evaporating the oil phase to remove the solvent, and adding alkali liquor for neutralization.

In the above technical solution, the preparation method of the cationic-nonionic surfactant is preferably:

a) r is to be₁COOR₀、

Amidation reaction to obtain

b) Will be provided with

In an organic solvent with

Carrying out quaternization reaction to obtain the cationic-nonionic surfactant.

In the above technical solution, R in the step a) is₁COOR₀、

The molar ratio of (A) to (B) is preferably 1 (1.05-1.35), more preferably 1: 1.2; the reaction temperature of the amidation reaction is preferably 140-165 ℃, and the reaction time is preferably 3-6 hours; in said step b)

And

the molar ratio of (A) to (B) is preferably 1 (1.05-1.2), more preferably 1: 1.1; the reaction temperature of the quaternization reaction is preferably 60-90, the reaction time is preferably 4-10 hours, the organic solvent is preferably one of ethanol and isopropanol, and the organic solvent is preferably ethanol or isopropanol

Preferably 2-chloroethanol, 3-chloropropanol and 4-chlorobutanol.

In the technical scheme, the mole ratio of the anionic-nonionic surfactant to the cationic-nonionic surfactant is preferably 1 (0.1-10).

In order to solve the third technical problem, the technical scheme adopted by the invention is as follows: use of a surfactant composition according to any of the above-mentioned solutions to solve one of the technical problems in tertiary oil recovery.

In the above technical solution, the application is not limited, for example, but not limited, the application is used for three times of using for improving the recovery ratio, reducing the pressure and increasing the injection of an oil-water well, and the like.

In the above technical solution, the application method can be utilized by those skilled in the art according to the method of depressurization and injection enhancement of the surfactant in the prior art, and there is no special requirement, for example but not limited to injecting the low concentration surfactant group in-situ microemulsion system into the reservoir formation in the form of an aqueous solution to contact with the underground crude oil, so as to unlock and displace the underground crude oil; wherein, in the surfactant composition water solution, the concentration of the surfactant composition is 0.2-0.5% by mass of the total mass of the cationic surfactant and the anionic surfactant.

In the above technical solution, the surfactant composition is particularly suitable for tertiary oil recovery applications of low permeability high temperature high salt reservoirs, such as but not limited to: the temperature is 120 ℃, the total mineralization degree is 7500-90000 mg/L, and the permeability is 4.5 mD.

In order to solve the fourth technical problem, the invention adopts the technical scheme that: a method for enhanced oil recovery comprising the steps of injecting an aqueous solution of the surfactant composition according to any one of the above-mentioned solutions to one of the technical problems or the surfactant composition prepared by the preparation method according to any one of the above-mentioned solutions to the other of the technical problems into an oil reservoir formation, and producing an O/W (oil in water) microemulsion.

In the technical scheme, the surfactant composition is injected into an oil reservoir stratum in the form of aqueous solution, and forms O/W microemulsion after contacting with underground crude oil to displace the underground crude oil.

In the technical scheme, the concentration of the surfactant composition in the aqueous solution of the surfactant composition is 0.2-0.5% by mass of the total mass of the cationic-nonionic surfactant and the anionic-nonionic surfactant.

According to the invention, the cation-nonionic surfactant containing the amide special structure is compounded with the anion-nonionic surfactant designed by the special chain segment, so that the composition has good emulsification speed and solubilization capacity, and simultaneously has high interfacial activity, and achieves good balance between the interfacial activity and the emulsification speed, thereby forming the surfactant suitable for the pressure reduction and injection increase of a high-temperature, high-salinity and low-permeability oil reservoir and playing a good role in pressure reduction and injection increase; the field application shows that the surfactant composition system is injected into a stratum from a water injection well in the form of 0.5 wt% aqueous solution, can be quickly emulsified by virtue of the high solubilizing capacity of the surfactant composition system on organic plugs such as emulsified crude oil, paraffin, asphalt and the like in a shaft and the stratum, can form O/W type microemulsion in situ, forms the in-situ microemulsion, has the capacity of ultralow interfacial tension with the crude oil and the stratum water, the capacity of improving the wettability of the stratum and the capacity of dispersing inorganic small particles, has very small viscosity and particle size (dozens to hundreds of nanometers), has strong fluidity, is easy to produce from an oil well, can effectively relieve the blockage of an oil-water well, realizes the technical purpose of reducing the pressure and increasing the injection to improve the recovery ratio of the low-permeability oil, and has excellent pressure and increasing performance. In addition, the surfactant composition disclosed by the invention also has the advantages of temperature resistance, salt tolerance, high interfacial activity, high oil washing capacity, solubilization capacity and the like of the traditional anion-cation compound surfactant, and plays a good role in improving the crude oil recovery rate.

By adopting the technical scheme of the invention, the obtained surfactant composition has the characteristics of high temperature resistance, high salt resistance, strong plugging removal capability, large pressure reduction and injection increase amplitude, long service life, simple system composition, convenient preparation, small environmental pollution (no organic solvent), and the like, can be suitable for ultra-low permeability oil reservoirs with the total mineralization of 90000mg/L at 120 ℃, has high emulsification speed, can form a microemulsion system with crude oil in situ, can be used for rapid plugging removal, and simultaneously has extremely high interfacial activity, and the surfactant composition can still form 10 percent with underground crude oil under the condition that the dosage is 0.01-0.05 percent by weight^-3～10^-4An ultra-low interfacial tension of mN/m; the surfactant composition has good effects of reducing pressure and increasing injection, and improving the recovery ratio, and meanwhile, the surfactant composition is simple and easy to prepare, and easy to demulsify, solves the problem of difficulty in demulsification of oil extraction by using the existing surfactant emulsion, and obtains good technical effects.

Drawings

FIG. 1 shows 10 of a 0.005 wt% surfactant composition with Jidong crude oil^-4mN/m ultra-low interfacial tension diagram.

FIG. 2 is a 10 plot of a 0.1 wt% concentration surfactant composition with victory crude oil^-4mN/m ultra-low interfacial tension diagram.

FIG. 3 shows the phase results of surfactant composition system and Jidong crude oil at different concentrations (test temperature 120 ℃ C., formation water average mineralization: 7516 mg/l).

FIG. 4 is a graph showing the phase and solubility of surfactant in-situ microemulsion and Shengli crude oil at different concentrations under WOR 2 (test temperature 120 ℃, average degree of mineralization of formation water: 90046 mg/l).

FIGS. 5-9 are graphs of the effects of in situ depressurization and stimulation for a 0.5 wt% temperature and salt tolerant surfactant in situ microemulsion ultra-low permeability reservoir (FIG. 5 is the production curve for the well of example 17, FIG. 6 is the production curve for the well of example 18, FIG. 7 is the production curve for the well of example 19, FIG. 8 is the production curve for the well of example 20, and FIG. 9 is the production curve for the well of example 21).

The invention is further illustrated by the following examples.

Detailed Description

[ example 1 ]

1) Preparation of alkyl phenol polyoxypropylene polyoxyethylene carboxylate or sulfonate

Adding alkylphenol with the required chain length, potassium hydroxide and the required amount of propylene oxide and ethylene oxide (determined by the number of n and m) into a polymerization kettle in sequence, and reacting for 1-5 hours at 120-160 ℃ with the pressure controlled to be less than or equal to 0.50 MPa; then adding an organic solvent, sodium hydroxide, sodium chloroacetate or 2-chloroethyl sodium sulfonate, wherein the alkylphenol polyoxypropylene polyoxyethylene ether: sodium hydroxide: the molar ratio of sodium chloroacetate to 2-chloroethyl sodium sulfonate is 1:1.5 (1.2-1.5), the reaction is continued for 2-10 hours at 50-100 ℃, then hydrochloric acid is added to adjust the pH value to be less than 3, oil-water separation is carried out, the oil phase is evaporated to remove the solvent and then added with alkali liquor to neutralize, and finally the needed alkylphenol polyoxypropylene m polyoxyethylene ether n sulfonate or alkylphenol polyoxypropylene m polyoxyethylene ether n sulfonate is obtained;

2) preparation of N, N-fatty acid amide propyl dialkyl methyl hydroxyalkyl ammonium chloride

a) Carrying out amidation reaction on fatty acid methyl ester with the required chain length and N, N-dimethyl-1, 3-propane diamine (1:1.2) with the required amount at the temperature of 140-165 ℃ for 3-6 hours to prepare corresponding N, N-dimethyl fatty acid amido propane diamine;

b) dissolving the product obtained in the step a) in an organic solvent, slowly adding halogenated aliphatic alcohol (2-chloroethanol, 3-chloropropanol, 4-chlorobutanol and the like) according to the proportion of 1:1.1 at the temperature of 60-90 ℃, and reacting for 4-10 hours. After the reaction is finished, the solvent is evaporated to obtain the fatty acid amide propyl dimethyl hydroxyalkyl ammonium chloride product. Wherein the solvent is selected from one of ethanol and isopropanol.

3) Preparation of in-situ microemulsion surfactant mixed system

Respectively dissolving the anionic-nonionic surfactant and the cationic-nonionic surfactant obtained in the steps (1) and (2) into water, and uniformly mixing according to the molar ratio of 1 (0.1-10) to obtain the required in-situ microemulsion surfactant composition.

[ example 2 ]

Sodium octylphenol polyoxypropylene polyoxyethylene ether carboxylate (m 9, n 6) prepared according to [ example 1 ] and lauric acid amide propyl dimethyl hydroxyethyl chloride surfactant were dissolved in total mineralization of 60000mg/L and Ca, respectively²⁺+Mg²⁺3000mg/L of simulated water is prepared into 1.0 percent by weight of aqueous solution, and then the surfactant solution is evenly mixed (stirred for 30 minutes) according to the molar ratio of 1:0.5 of anion-nonionic surfactant to cation-nonionic surfactant to obtain the in-situ microemulsion surfactant composition product solution 1 a.

[ example 3 ]

Sodium nonylphenol polyoxypropylene polyoxyethylene ether carboxylate (m-7, n-5) prepared according to [ example 1 ] and cocamidopropyl dimethylhydroxyethylammonium chloride were dissolved in 50000mg/L total degree of mineralization, Ca, respectively²⁺+Mg²⁺3000mg/L of simulated water is prepared into 1.0 percent of water solution by weight, and then the surfactant solution is evenly mixed (stirred for 30 minutes) according to the proportion of 1:0.15 (molar ratio) of the anionic-nonionic surfactant to the cationic-nonionic surfactant to obtain the in-situ microemulsion surfactant composition solution 2 a.

[ example 4 ]

Sodium nonylphenol polyoxypropylene polyoxyethylene ether sulfonate (m ═ 6, n ═ 2) prepared according to [ example 1 ] and erucamide propyl dimethylhydroxybutyl ammonium chloride surfactant were dissolved in a total degree of mineralization of 300000mg/L, Ca respectively²⁺+Mg²⁺1500mg/L of simulated water is prepared into 1.0 percent by weight of aqueous solution, and then the surfactant solution is prepared according to the molar ratio of 1:9 (mol ratio) of anionic-nonionic to cationic-nonionic surfactantExample, mix well (stir for 30 minutes) to give the in situ microemulsion surfactant composition solution 3 a.

[ example 5 ]

Sodium nonylphenol polyoxypropylene polyoxyethylene ether sulfonate (m ═ 9, n ═ 10) prepared according to [ example 1 ] and erucamide propyl dimethyl hydroxypropyl ammonium chloride surfactant were dissolved in total salinity of 300000mg/L, Ca was dissolved in each case²⁺+Mg²⁺1500mg/L of simulated water is prepared into 1.0 percent of water solution by weight, and then the surfactant solution is evenly mixed (stirred for 30 minutes) according to the molar ratio of 1:3.5 of anion-nonionic surfactant to cation-nonionic surfactant to obtain the in-situ microemulsion surfactant composition solution 4 a.

[ example 6 ]

Sodium nonylphenol polyoxypropylene polyoxyethylene ether carboxylate (m 10, n 6) prepared according to [ example 1 ] and erucamide propyl dimethyl hydroxypropyl ammonium chloride surfactant were dissolved in total salinity of 300000mg/L, Ca²⁺+Mg²⁺1500mg/L of simulated water is prepared into 1.0 percent of water solution by weight, and then the surfactant solution is evenly mixed (stirred for 30 minutes) according to the molar ratio of 1:0.8 of anion-nonionic surfactant to cation-nonionic surfactant to obtain the in-situ microemulsion surfactant composition solution 5 a.

[ example 7 ]

Sodium dodecylphenol polyoxypropylene polyoxyethylene ether sulfonate (m 6, n 6) prepared according to [ example 1 ] and oleamide propyl dimethyl hydroxypropyl ammonium chloride surfactant were dissolved in total salinity of 300000mg/L, Ca respectively²⁺+Mg²⁺1500mg/L of simulated water is prepared into 1.0 percent of water solution by weight, and then the surfactant solution is evenly mixed (stirred for 30 minutes) according to the proportion of 1:0.25 (molar ratio) of the anionic-nonionic surfactant to the cationic-nonionic surfactant to obtain the in-situ microemulsion surfactant composition solution 6 a.

[ example 8 ]

Sodium dodecylphenol polyoxypropylene polyoxyethylene ether carboxylate (m 4, n 5) prepared as described in reference [ example 1 ] was mixed with amidopropyl dimethyl hydroxyethyl ammonium palmitateSurfactant dissolved in total salinity of 300000mg/L, Ca respectively²⁺+Mg²⁺1500mg/L of simulated water is prepared into 1.0 percent by weight of aqueous solution, and then the surfactant solution is evenly mixed (stirred for 30 minutes) according to the molar ratio of 1:0.54 of anion-nonionic surfactant to cation-nonionic surfactant to obtain the in-situ microemulsion surfactant combined solution 7 a.

[ example 9 ]

Sodium dodecylphenol polyoxypropylene polyoxyethylene ether sulfonate (m 5, n 7 and oleamide propyl dimethyl hydroxypropyl ammonium chloride surfactant, prepared according to reference [ example 1 ], were dissolved in total mineralization of 300000mg/L, Ca respectively²⁺+Mg²⁺1500mg/L of simulated water is prepared into 1.0 percent of water solution by weight, and then the surfactant solution is evenly mixed (stirred for 30 minutes) according to the molar ratio of 1:4 of anion-nonionic to cation-nonionic surfactant to obtain the in-situ microemulsion surfactant composition solution 8 a.

[ example 10 ]

Pentadecylphenol polyoxypropylene polyoxyethylene ether carboxylic acid sodium salt (m 4, n 7) prepared according to [ example 1 ] and palmitic acid amidopropyl dimethylhydroxyethyl ammonium chloride surfactant were dissolved in total salinity of 300000mg/L, Ca respectively²⁺+Mg²⁺1500mg/L of simulated water is prepared into 1.0 percent of water solution by weight, and then the surfactant solution is evenly mixed (stirred for 30 minutes) according to the molar ratio of 1:0.5 of anion-nonionic surfactant to cation-nonionic surfactant to obtain the in-situ microemulsion surfactant composition solution 9 a.

[ example 11 ]

Pentadecylphenol polyoxypropylene polyoxyethylene ether carboxylic acid sodium salt (m is 5, n is 8) prepared according to example 1 and oleic acid myristamide propyl dimethyl hydroxybutyl ammonium chloride surfactant were dissolved in total salinity of 300000mg/L, Ca respectively²⁺+Mg²⁺Preparing 1.0 wt% aqueous solution in 1500mg/L simulated water, and uniformly mixing (stirring for 30 minutes) the surfactant solution according to the molar ratio of 1:5 (of anionic-nonionic surfactant to cationic-nonionic surfactant) to obtain the in-situ microemulsion surfactantAgent composition solution 10 a.

[ example 12 ]

Pentadecylphenol polyoxypropylene polyoxyethylene ether sodium sulfonate (m ═ 2, n ═ 7 palmitamide propyl dimethylhydroxyethyl ammonium chloride surfactant) prepared according to [ example 1 ], was dissolved in total salinity of 300000mg/L, Ca respectively²⁺+Mg²⁺1500mg/L of simulated water to prepare 1.0% wt aqueous solution, and then mixing the surfactant solution according to the weight ratio of anion-nonionic to cation-nonionic surfactant 1: 0.43 (molar ratio) is mixed evenly (stirred for 30 minutes) to obtain the in-situ microemulsion surfactant composition solution 11 a.

[ example 13a ] interfacial Property test of surfactant in situ microemulsion composition

1. Reservoir characteristics

(1) The oil reservoir characteristics of the southbound operation area of the Jidong oil field are an ultra-high temperature, low mineralization and low permeability oil reservoir.

Oil layer temperature: 120 ℃;

formation level average degree of mineralization: 7516 mg/l;

average permeability of the formation: 4.5X 10^-3μm²；

(2) Super-high temperature, high salinity, low permeability reservoir characteristic of reservoir in Binhe zone of Shengli oil field

Oil layer temperature: 120 ℃;

formation level average degree of mineralization: 90046 mg/l;

average permeability of the formation: 71.6X 10^-3μm²；

2. Oil-water interfacial tension test conditions and test results:

interfacial tension between the 0.1-0.5% in-situ microemulsion surfactant in-situ aqueous solution and 649 crude oils of the oil field of the southeast castle and the oil field of the victory oil field as described in examples 2-12 is measured by a Dataphysics SVTN 20 high-temperature video spinning drop interfacial tension meter, and test results are shown in the following table. (notes: surfactant solutions were formulated with oilfield field water in all experiments) test temperatures: 120 ℃;

test oil: fresh crude oil of Ji southeast fort oil field and fresh crude oil of Shengli oil field Binshui area

Test water: jidong oilfield field water (average mineralization degree: 7516mg/L), Shengli oilfield field water (average mineralization degree: 90046 mg/L);

and (3) testing temperature: 120 ℃;

TABLE 1 surfactant composition oil-water interfacial tension

[ example 13b ] ultra-Low interfacial tension Window test for surfactant composition one

The surfactant composition described in example 8 was selected, and oil-water interfacial tension concentration window tests were performed at 120 ℃ using a Dataphysics SVTN 20 high-temperature video spinning drop interfacial tensiometer using the surfactant composition of example 8 to prepare surfactant samples of different concentrations with the oil field formation water of Jidong (formation level average degree of mineralization: 7516mg/L), the test results are shown in Table 2 and FIG. 1.

TABLE 2 interfacial tension test results for different concentrations of surfactant composition and Jidong crude oil

Concentration wt%	0.01	0.025	0.05	0.1	0.3	0.5
							Interfacial tension mN/m	0.00352	0.00167	0.000154	0.00041	0.00039	0.00038

The results show that the surfactant composition has high oil-water interfacial activity on crude oil in Jidong oil fields.

[ example 13c ] ultra Low interfacial tension Window test for surfactant composition II

The surfactant composition described in example 10 was selected, formation water (formation level average degree of mineralization: 90046mg/L) in the Binhe zone of the Shengli oilfield was used to prepare surfactant samples of different concentrations, and oil-water interfacial tension concentration window test was performed at 120 ℃ using a Dataphysics SVTN 20 high temperature video spinning drop interfacial tensiometer, the test results are shown in Table 3 and FIG. 2.

TABLE 3 results of interfacial tension test of different concentrations of surfactant composition and victory crude oil

Concentration wt%	0.01	0.025	0.05	0.1	0.3	0.5
							Interfacial tension mN/m	0.001352	0.00189	0.000354	0.00027	0.00039	0.00052

[ COMPARATIVE EXAMPLE 1 ]

Sodium dodecylphenol polyoxypropylene polyoxyethylene ether carboxylate (m 4, n 5) prepared according to [ example 1 ] and cetyldimethylhydroxyethylammonium chloride surfactant were dissolved in a total salinity of 300000mg/L, Ca respectively²⁺+Mg²⁺1500mg/L of simulated water is prepared into 1.0 percent by weight of aqueous solution, and then the surfactant solution is evenly mixed (stirred for 30 minutes) according to the molar ratio of the anionic-nonionic surfactant to the cationic-nonionic surfactant of 1:0.54 to obtain the surfactant combined solution 1 b.

Interfacial tension window testing was performed as in example 13b and the results are shown in Table 2b

TABLE 2b interfacial tension test results for different concentrations of surfactant and Jidong crude oil

Concentration wt%	0.01	0.025	0.05	0.1	0.3	0.5
							Interfacial tension mN/m	0.0543	0.0236	0.0179	0.0100	0.00726	0.00853

The results show that the surfactant composition has high oil-water interfacial activity for crude oil in oil fields in Jidong and has a wide interface activity concentration window from low concentration to high concentration, while comparative example 1 has high interfacial activity only under the condition of high concentration and has a narrow concentration window; and has poor crude oil solubilization capacity and slow emulsification speed.

[ example 14a ] evaluation of solubilizing ability of surfactant composition

The in-situ microemulsion forming ability and solubilization parameters of the 0.5 wt% surfactant composition oilfield field aqueous solution and the target oilfield crude oil described in examples 2-12 were carried out using a glass capillary phase equilibrium method, and the test results are shown in table 4:

the glass capillary phase equilibrium experiment method is the most scientific and visual evaluation method for researching a microemulsion system and can simulate oil reservoir conditions more truly: a certain amount of surfactant solution and crude oil are added into a temperature-resistant pressure-resistant glass tube with scales according to different oil-water ratios (WOR) and then sealed, and the quality and the liquid level of the surfactant solution and the crude oil are recorded. Then, the oil and water are mixed evenly by adopting a manual or mechanical shaking means, and finally the mixture is placed in a temperature-resistant and pressure-resistant sealable glass test tube filled with colorless silicone oil and is placed in a metal bath set to the oil reservoir temperature (120 ℃) to be heated and balanced for several days to several weeks until the oil and water level is not changed any more and the stability of the microemulsion system is observed continuously in a balanced way (several months or even several years). The Solubilization Parameters (SP) of the oil phase and the water phase can be calculated according to the change of the oil-water interface liquid level:

wherein V_iIs the volume of the aqueous or oil phase in the microemulsion, V_sIs the surfactant volume.

Optimum solubilization parameter SP^*Is a function of salinity or surfactant composition:

TABLE 4 solubilization parameters of in situ microemulsions of surfactant composition solutions

WOR-1 in this experiment, 1ml of crude oil and 1ml of 0.5 wt% surfactant were added

[ example 14b ] evaluation of solubilization Capacity of in situ microemulsion of surfactant composition at different oil-to-Water ratios

Referring to [ example 14a ] phase equilibrium method, the surfactant in-situ microemulsion described in example 8 is applied to prepare 0.5% -4.0% oilfield field aqueous solution, and then the microemulsion forming capability and solubilization parameter test of the surfactant in-situ microemulsion and the crude oil in the eastern Ji oilfield are performed according to the oil-water ratio of 50:50, and the results are shown in the attached figure 3, and the results show that the surfactant in-situ microemulsion forms stable O/W type lower phase microemulsion under different 1.0% -4.0% high concentrations, can form Winsor III phase microemulsion with highest oil displacement efficiency under 0.5% low concentration, and has excellent crude oil solubilization capability SP-28.

[ example 14c ] evaluation of solubilization Capacity of in situ microemulsions of surfactant compositions at different concentrations

Referring to [ example 14a ], the surfactant in-situ microemulsion described in example 10 was applied, and the capability of forming microemulsion with crude oil in the mafringen zone in situ and solubilization parameters were examined by using WOR-2 water-oil ratio under different concentrations, and the results show that the surfactant in-situ microemulsion system can form stable O/W type lower phase microemulsion (bluing light) with the mafringen crude oil under the formation conditions at the lower use concentration of 0.5%, and the solubilization parameters are about 24. The shape of the microemulsion is shown in figure 4.

[ example 15 ] surfactant composition in-situ microemulsion oil-washing Capacity test

Cleaning target oil reservoir stratum sand, grinding and sieving for later use, uniformly mixing the sand with target crude oil according to the saturation of residual oil, aging the sand for 7 days at the oil reservoir temperature, taking out 5 g of aged oil sand, and then performing oil sand treatment according to the weight ratio of the oil sand: 0.5 percent of surfactant in-situ microemulsion solution is added into the solution according to the proportion of 1:10 and is uniformly mixed, oil sand and the oil-containing surfactant solution are separated after the mixture is stood for 72 hours at the oil reservoir temperature, the oil washing capacity is calculated by measuring the residual oil in the oil sand by a thermogravimetric method, and the result is shown in table 3.

TABLE 3 oil wash results for surfactant compositions

Examples	Oil washing rate% (Jidong crude oil)	Oil washing rate% (victory crude oil)
			2	48.51	49.57
3	47.23	50.20
			4	56.28	48.86
5	61.31	46.35
			6	59.60	60.72
7	62.54	63.95
			8	65.19	66.45
9	47.03	49.38
			10	66.25	64.55
11	56.87	46.89
			12	48.33	49.63

[ example 16 ] core Displacement test for in situ microemulsion flooding and depressurization Performance of 0.2% surfactant composition

1. Displacement experimental conditions

(1) Performing a displacement experiment by using an artificial core, wherein the core length is 9.10cm, the diameter is 2.50cm, and the gas logging permeability is 72.6 mD%;

(2) displacement water: formation water in Binei region of Shengli oil field

(3) Oil for displacement: fresh crude oil in Binshou region of Shengli oil field

2. Experimental procedure

(1): drying the cleaned rock core, measuring the size length and diameter of the rock core, saturating and injecting water at room temperature, and measuring the porosity and the pore volume;

(2) saturating the crude oil at 120 ℃, and aging overnight;

(3) injection speed: 0.05ml/min, and the displacement experiment temperature is 120 ℃;

(4) after the water is driven to contain 98 percent of water, 0.2 percent by weight of surfactant composition solution 0.1PV is injected, and the pressure, the oil production and the water production are recorded every 5 min;

(5) and (4) performing subsequent water flooding until the water content is 100%, recording the pressure, the oil production and the water production every 10min until the oil production is not increased within 30min, stopping flooding, calculating the recovery ratio according to the liquid production and the water content of each stage, and automatically collecting the pressure by a pressure sensor in the whole experimental process.

Using the surfactant composition described in example 7 as a displacement medium, with a concentration of 0.2% wt, a displacement rate of 0.05mL/min, and injection of 0.1PV surfactant solution, it was found that a further improvement in recovery of 9.71% was achieved on a water flooding basis. The blood pressure reducing rate reaches 39.03 percent, and the blood pressure reducing effect is obvious.

Example 17 one of the examples of in situ microemulsion pressure-reducing injection-increasing yield-increasing field application of surfactant composition

In a certain well (oil layer temperature 120 ℃, permeability 4.5mD) of a certain operation area of the Jidong oil field, the accumulated water injection amount of the well is 11400m before the surfactant in-situ microemulsion pressure-reducing injection-increasing agent is implemented³The surfactant in-situ microemulsion pressure-reducing injection-increasing agent of the embodiment 8 is injected into 50m by 0.5 weight percent of field injection aqueous solution at the oil pressure of 30MPa in normal water injection and in 2016 for 11 months³Then, the average daily water injection amount is 10m³Lifting/d to 30m³D, the water injection oil pressure is always stabilized at about 16.5MPa, the pressure reduction rate reaches more than 45 percent, and then the injection allocation is improved to 50m³D, keeping the injection pressure at about 20MP, corresponding to the oil well, increasing the daily oil production from 1.5t/d to 3.7t/d after the measures, and increasing the injection quantity by 4962m until 5 months and 2 days in 2017³. The normal water injection is still kept until now, and the use period of validity reaches one year. The production curve is shown in figure 5, the left ordinate is oil pressure, and the right ordinate is water injection quantity.

EXAMPLE 18 surfactant composition in situ microemulsion depressurization augmented injection stimulation in-situ application example two

In a certain well (oil layer temperature 120 ℃, permeability 4.5mD) in a certain operation area of the Yidong oil field, the well is changed from the oil well to water injection in 2016, the oil pressure of the well is 30MPa before construction, and the daily injection is 30m³Daily water injection of 19m³. The surfactant in-situ microemulsion pressure-reducing injection-increasing agent has remarkable pressure-reducing injection-increasing effect after being applied and implemented in 2016, 12 months and 1 day, and can reach 30m of daily water injection³And the water injection oil pressure is reduced to 6-7MPa (the highest pressure reduction rate reaches 76%), the daily oil production is increased to 5.8t/d from 3.3t/d after measures are taken for the corresponding oil well, the water injection pressure is stabilized at 9MPa all the time after 2017, 5 and 2 months, the oil is increased by 372.5t in an accumulated manner, normal water injection is still kept at present, and the service life reaches one year. The production curve is shown in figure 6, the left ordinate is oil pressure, and the right ordinate is water injection quantity.

EXAMPLE 19 surfactant composition in situ microemulsion depressurization augmented injection stimulation in-situ application example III

In a certain well (oil layer temperature 120 ℃, permeability 4.5mD) of a certain operation area of the Yidong oil field, the well is changed from the oil well to water injection in 2016, 12 months, the oil pressure of the well is 30MPa before construction, and the daily injection is 40m³10m of daily water³. After the surfactant in-situ microemulsion pressure-reducing injection-increasing agent is applied and implemented in 2017, 3, 25 days, the pressure-reducing injection-increasing effect is remarkable, the water injection starting pressure is reduced by 10MPa and then stabilized at 20MPa (the highest pressure-reducing rate reaches 33%), and the daily water injection reaches 44m³Corresponding to an oil well, the daily oil production is increased from 7.3t/d to 8.8t/d after the measures, the oil increasing effect is obvious, normal water injection is still kept at present, and the service life is more than half a year. The production curve is shown in figure 7.

EXAMPLE 20 surfactant composition in situ microemulsion depressurization augmented injection stimulation four examples of in situ applications

And (3) transferring the injection of a certain well (the oil layer temperature is 120 ℃, the permeability is 4.5mD) in a certain operation area of the oil field in the east of Ji, the injection pressure in 5 months in 2013 is 30MPa before measures, the water injection pump frequently fails due to high pressure and is often in a pump-stopping maintenance state, the injection pressure is 31MPa in 2 months and 21 days in 2017 and 23 days in 3 months and 23 days in 2017, and the daily injection amount is 0. 2016.12.1 the effect is obvious after the surfactant in-situ microemulsion is depressurized and augmented, the injection allocation is completed, and the daily water injection reaches 30m³The injection pressure is reduced to 18MPa, and is always stabilized at 20MPa at present. Cumulative increase of 1020m by 5, 2 and 5 months in 2017³. Corresponding to an oil well, the daily oil production is increased from 3.8t/d to 8.5t/d after the measures, normal water injection is still kept at present, and the service life is close to one year. The production curve is shown in figure 8.

EXAMPLE 21 surfactant composition in situ microemulsion depressurization augmented injection stimulation in situ application example five

In a certain well (oil layer temperature 120 ℃, permeability 4.5mD) of a certain operation area of the Jidong oil field, 3-month injection in 2016 years, water injection oil pressure 18MPa and daily injection allocation 70m³35m of daily water³In 2016, booster pump is used to increase injection pressure to 36MPa and daily water injection to 60m³. 2017.4.14 the effect of pressure reduction and injection increase is obvious after the surfactant in-situ microemulsion is unblocked, injection allocation is finished, and the injection pressure is reduced to 25MPa, and the oil production per day is increased from 4.4t/d to 5.7t/d after the measures, normal water injection is still kept at present, and the service life reaches half a year. The production curve is shown in figure 9.

Claims

1. A surfactant composition comprises an anionic-nonionic surfactant and a cationic-nonionic surfactant, wherein the molar ratio of the anionic-nonionic surfactant to the cationic-nonionic surfactant is (1-100) to (1-100); wherein the structural general formula of the cationic-nonionic surfactant is shown as the formula (I):

2. The surfactant composition of claim 1, wherein X is^—is-Cl^—、-Br^—、-I^—Or CH₃COO^-、NO₃ ^-At least one of; m is selected from ammonium ion or monovalent metal ion.

3. The surfactant composition of claim 1, wherein R is₁Is C₁₂～C₂₂Alkyl of R₂、R₃Is independently selected from C₁～C₄P1 and p2 are independently selected from any integer of 1-4, X^—is-Cl^—、-Br^—At least one of (1).

4. The surfactant composition of claim 1, wherein R is₄Is C₂～C₂₂Is preferably C₂～C₂₂More preferably C₂～C₂₂Alkyl and/or alkenyl groups of (a); q is selected from any integer of 1 to 4, and more preferably any integer of 2 to 3.

5. The surfactant composition of claim 1, wherein the molar ratio of anionic-nonionic surfactant to cationic-nonionic surfactant is (1-10) to (1-10).

6. A method of preparing a surfactant composition comprising the steps of:

uniformly mixing an anionic-nonionic surfactant and a cationic-nonionic surfactant with optional water according to a molar ratio of 1 (0.01-100) to obtain the surfactant composition;

7. The method of claim 6, wherein X is selected from the group consisting of^—is-Cl^—、-Br^—、-I^—Or CH₃COO^-、NO₃ ^-At least one of; m is selected from ammonium ion or monovalent metal ion.

8. The method of claim 6, wherein R is selected from the group consisting of₁Is C₁₂～C₂₂Alkyl of R₂、R₃Is independently selected from C₁～C₄P1 and p2 are independently selected from any integer of 1-4, X^—is-Cl^—、-Br^—At least one of (1).

9. The method of claim 6, wherein R is selected from the group consisting of₄Is C₂～C₂₂Is preferably C₂～C₂₂More preferably C₂～C₂₂Alkyl and/or alkenyl groups of (a); q is any integer of 2-3.

10. The method for preparing the surfactant composition according to any one of claims 6 to 9, wherein the anionic-nonionic surfactant is prepared by:

1) will be provided with

In the presence of catalyst A according to

2) Will be provided with

11. The method for preparing the surfactant composition according to claim 10, wherein the alkoxylation reaction is carried out at a reaction temperature of 100 to 200 ℃ for 1 to 5 hours; the carboxylation or sulfonation reaction is carried out in an organic solvent, the reaction temperature is 50-100 ℃, and the reaction time is 2-10 hours; the catalyst A and the catalyst B are independently selected from alkali metal hydroxides, and are more independently selected from one of sodium hydroxide or potassium hydroxide; the carboxylating agent or sulfonating agent is

Wherein X₀Is a halogen substituent, M₀Is H⁺Ammonium ions or metal ions; y is carboxylate or sulfonate.

12. The method for preparing the surfactant composition according to any one of claims 6 to 9, wherein the method for preparing the cationic-nonionic surfactant comprises:

a) r is to be₁COOR₀、

Amidation reaction to obtain

b) Will be provided with

In an organic solvent with

13. The method of preparing the surfactant composition according to claim 12, wherein R in the step a)₁COOR₀、

The molar ratio of (A) to (B) is 1 (1.05-1.35), more preferably 1: 1.2; the reaction temperature of the amidation reaction is 140-165 ℃, and the reaction time is 3-6 hours; in said step b)

And

the molar ratio of (A) to (B) is 1 (1.05-1.2), more preferably 1: 1.1; the reaction temperature of the quaternization reaction is 60-90, the reaction time is 4-10 hours, and the organic solvent is selected from one of ethanol and isopropanol.

14. The method for preparing the surfactant composition according to any one of claims 6 to 9, wherein the molar ratio of the anionic-nonionic surfactant to the cationic-nonionic surfactant is 1 (0.1 to 10).

15. Use of a surfactant composition according to any one of claims 1 to 5 in enhanced oil recovery.

16. A method for enhancing oil recovery, comprising the steps of injecting the surfactant composition of any one of claims 1 to 5 or the aqueous solution of the surfactant composition prepared by the preparation method of any one of claims 6 to 14 into an oil reservoir formation, and producing an O/W microemulsion.

17. The method for enhanced oil recovery as claimed in claim 16 wherein the surfactant composition is injected into the reservoir formation in the form of an aqueous solution to contact the subterranean oil to form an O/W microemulsion to displace the subterranean oil.

18. The enhanced oil recovery method according to claim 16, wherein the surfactant composition is contained in an aqueous solution at a concentration of 0.2 to 0.5% by mass based on the total mass of the cationic and anionic nonionic surfactants.