阅读说明：本技术 一种环保驱油用粘弹润湿表面活性剂及其制备方法 (Environment-friendly viscoelastic wetting surfactant for oil displacement and preparation method thereof ) 是由 李会勇 郑金中 杜明慧 王伟强 崔健 于 2021-02-09 设计创作，主要内容包括：本发明涉及驱油表面活性剂技术领域,尤其涉及一种环保驱油用粘弹润湿表面活性剂及其制备方法。采用以非离子表面活性剂和离子表面活性剂混合使用的方法,首先向反应釜中加入聚醚碳链,保持反应中温度恒定,然后加入烷基磺酸盐,搅拌均匀,反应1h左右；待反应釜中物料混合完全后,同时向反应釜中加入椰油酰单乙醇胺和脂肪醇苯基乙烯醚,以增加混合物中醚键和羟基基团,增强有机混合物更加具有亲水性,混合均匀；然后向反应釜中滴加0.5%-1%氢氧化钠,调节溶液PH为8-9,抑制磺酸盐的水解,保证了混合物中磺酸基团和金属离子含量的恒定,使得驱油表面活性剂的驱油效果更佳。(The invention relates to the technical field of oil-displacing surfactants, in particular to an environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof. The method of mixing and using the nonionic surfactant and the ionic surfactant is adopted, firstly, polyether carbon chains are added into a reaction kettle, the temperature in the reaction is kept constant, then alkyl sulfonate is added, the mixture is uniformly stirred, and the reaction lasts for about 1 hour; after the materials in the reaction kettle are completely mixed, adding cocoyl monoethanolamine and fatty alcohol phenyl vinyl ether into the reaction kettle simultaneously to increase ether bonds and hydroxyl groups in the mixture, so that the organic mixture is enhanced to be more hydrophilic and uniformly mixed; then 0.5-1% of sodium hydroxide is dripped into the reaction kettle, the pH value of the solution is adjusted to 8-9, the hydrolysis of sulfonate is inhibited, the constancy of the contents of sulfonic acid groups and metal ions in the mixture is ensured, and the oil displacement effect of the oil displacement surfactant is better.)

1. An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized in that: the main raw materials are as follows: coconut oil, monoethanolamine, alkyl alcohol, fatty alcohol, phenyl vinyl alcohol, and the like; the gas raw materials are as follows: sulfur dioxide; the apparatus used comprises: a reaction kettle and an oxygen generator.

2. An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof, mainly comprises the following components: polyether carbon chain, alkyl sulfonate, cocoyl monoethanolamine, fatty alcohol phenyl vinyl ether and 0.5-1% sodium hydroxide aqueous solution.

3. The environment-friendly viscoelastic wetting surfactant for oil displacement and the preparation method thereof according to claim 1 are characterized by comprising the following steps:

preparing 0.5% -1% sodium hydroxide aqueous solution: firstly weighing 5-10g of sodium hydroxide solid powder, dissolving the sodium hydroxide solid powder in a beaker filled with distilled water, uniformly stirring, then pouring the sodium hydroxide solid powder into a 1L volumetric flask, washing the beaker for multiple times, pouring washing liquid into the volumetric flask, and fixing the volume for later use;

(2) preparing 5 to 10 percent of alkyl sulfonate: firstly, introducing sulfur dioxide and excessive oxygen into a reactor, adding a catalyst, and completely oxidizing the sulfur dioxide into sulfur trioxide; conveying sulfur trioxide into a reactor filled with alkyl alcohol, starting a stirrer, keeping the temperature of the reactor at 40-60 ℃, adding 1, 2-dihydroxypentanol, adjusting the pH of a reaction solution to about 4-5, and reacting for 1h under an acidic condition; continuously dropwise adding 5% sodium hydroxide aqueous solution to enable the pH of the alkyl sulfonate in the reactor to be 8-9, and enabling the alkyl sulfonic acid to react with sodium ions under the condition of a catalyst to obtain the alkyl sulfonate for later use;

(3) preparing fatty alcohol phenyl vinyl ether: dropwise adding concentrated sulfuric acid into phenyl vinyl alcohol, uniformly stirring, heating to 150 ℃ and 170 ℃, and then adding a proper amount of catalyst to generate phenyl vinyl ether; reducing the temperature of the reaction solution to about 60 ℃, adding fatty alcohol and a catalyst into the reaction solution, and reacting for 2 hours to obtain fatty alcohol phenyl vinyl ether for later use;

(4) and (2) sequentially dripping the prepared experimental reagent polyether carbon chain, alkyl sulfonate, cocoyl monoethanolamine and fatty alcohol phenyl vinyl ether into a reaction kettle according to a proportion, uniformly stirring, dripping 0.5-1% of sodium hydroxide aqueous solution to adjust the pH of the solution to 8-9, keeping the pH constant, and stirring for 2-3h to obtain the viscoelastic wetting surfactant for oil displacement.

4. The environment-friendly viscoelastic wetting surfactant for oil displacement and the preparation method thereof according to claim 2 are characterized in that: the polyether carbon chain is a chain molecule containing 12 to 21 carbon atoms.

5. The environment-friendly viscoelastic wetting surfactant for oil displacement and the preparation method thereof according to claim 2 are characterized in that: the molecular formula of the alkyl sulfonate is R1R2M structure; the R1 is alkyl or alkyl carbon chain structure; the R1 contains 12 to 20 carbon atoms; r2 is a sulfonic acid group; and M is active metal such as metal ions Na or K and the like.

6. The environment-friendly viscoelastic wetting surfactant for oil displacement and the preparation method thereof according to claim 2 are characterized in that: the coconut monoethanol amine is obtained by the reaction of coconut oil and monoethanol amine.

7. The environment-friendly viscoelastic wetting surfactant for oil displacement and the preparation method thereof according to claim 1 are characterized in that: the polyether carbon chain, the alkyl sulfonate, the cocoyl monoethanolamine and the fatty alcohol phenyl vinyl ether are nonionic surfactants.

Technical Field

The invention relates to the technical field of oil-displacing surfactants, in particular to an environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof.

Background

With the rapid development of modern science and technology, the energy consumption is more and more diversified, and particularly, oil gas becomes the most important energy in production and life; and all countries in the world face the difficult problem of exploitation technology, and when oil gas is exploited, troubles brought by natural environments such as drilling depth problem, rock stratum pressure problem and the like exist, a plurality of requirements on exploitation equipment, the advance degree of the equipment and the like also exist, and the exploitation efficiency of oil gas energy is influenced to a great extent.

In other technologies, such as some frequently neglected problems, when the equipment and the technology are relatively mature, crude oil is often adsorbed on the surface of the equipment when the exploitation equipment is in contact with oil gas under a rock stratum, so that a conveying port of the exploitation equipment becomes narrow, exploitation speed is influenced to a great extent, great manpower and material resource loss is caused, and the energy waste phenomenon and a series of problems of exploitation of oil gas are caused.

Disclosure of Invention

Aiming at the technical defects, the invention provides a viscoelastic wetting surfactant for environmental-friendly oil displacement and a preparation method thereof, wherein a method for mixing and using a nonionic surfactant and an ionic surfactant is adopted, firstly, polyether carbon chains are added into a reaction kettle, the temperature in the reaction is kept constant, then, alkyl sulfonate is added, and the mixture is uniformly stirred and reacts for about 1 hour; after the materials in the reaction kettle are completely mixed, adding cocoyl monoethanolamine and fatty alcohol phenyl vinyl ether into the reaction kettle simultaneously to increase ether bonds and hydroxyl groups in the mixture, so that the organic mixture is enhanced to be more hydrophilic and uniformly mixed; then 0.5-1% of sodium hydroxide is dripped into the reaction kettle, the pH value of the solution is adjusted to 8-9, the hydrolysis of sulfonate is inhibited, the constancy of the contents of sulfonic acid groups and metal ions in the mixture is ensured, the oil displacement effect of the oil displacement surfactant is better, and the oil displacement surfactant is more environment-friendly.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the main raw materials are as follows: coconut oil, monoethanolamine, alkyl alcohol, fatty alcohol, phenyl vinyl alcohol, and the like; the gas raw materials are as follows: sulfur dioxide; the apparatus used comprises: a reaction kettle and an oxygen generator.

Further optimizing the technical scheme, the main components are as follows: polyether carbon chain, alkyl sulfonate, cocoyl monoethanolamine, fatty alcohol phenyl vinyl ether and 0.5-1% sodium hydroxide aqueous solution.

Further optimizing the technical scheme, the viscoelastic wetting surfactant for environmental-friendly oil displacement and the preparation method thereof are characterized by comprising the following steps of:

(1) preparing 0.5% -1% sodium hydroxide aqueous solution: firstly weighing 5-10g of sodium hydroxide solid powder, dissolving the sodium hydroxide solid powder in a beaker filled with distilled water, uniformly stirring, then pouring the sodium hydroxide solid powder into a 1L volumetric flask, washing the beaker for multiple times, pouring washing liquid into the volumetric flask, and fixing the volume for later use;

(2) preparing 5 to 10 percent of alkyl sulfonate: firstly, introducing sulfur dioxide and excessive oxygen into a reactor, adding a catalyst, and completely oxidizing the sulfur dioxide into sulfur trioxide; conveying sulfur trioxide into a reactor filled with alkyl alcohol, starting a stirrer, keeping the temperature of the reactor at 40-60 ℃, adding 1, 2-dihydroxypentanol, adjusting the pH of a reaction solution to about 4-5, and reacting for 1h under an acidic condition; continuously dropwise adding 5% sodium hydroxide aqueous solution to enable the pH of the alkyl sulfonate in the reactor to be 8-9, and enabling the alkyl sulfonic acid to react with sodium ions under the condition of a catalyst to obtain the alkyl sulfonate for later use;

(3) preparing fatty alcohol phenyl vinyl ether: dropwise adding concentrated sulfuric acid into phenyl vinyl alcohol, uniformly stirring, heating to 150 ℃ and 170 ℃, and then adding a proper amount of catalyst to generate phenyl vinyl ether; reducing the temperature of the reaction solution to about 60 ℃, adding fatty alcohol and a catalyst into the reaction solution, and reacting for 2 hours to obtain fatty alcohol phenyl vinyl ether for later use;

(4) and (2) sequentially dripping the prepared experimental reagent polyether carbon chain, alkyl sulfonate, cocoyl monoethanolamine and fatty alcohol phenyl vinyl ether into a reaction kettle according to a proportion, uniformly stirring, dripping 0.5-1% of sodium hydroxide aqueous solution to adjust the pH of the solution to 8-9, keeping the pH constant, and stirring for 2-3h to obtain the viscoelastic wetting surfactant for oil displacement.

Further optimizing the technical scheme, the polyether carbon chain is a chain molecule containing 12 to 21 carbon atoms.

Further optimizing the technical scheme, the molecular formula of the alkyl sulfonate is R1R 2M; the R1 is alkyl or alkyl carbon chain structure; the R1 contains 12 to 20 carbon atoms; r2 is a sulfonic acid group; and M is active metal such as metal ions Na or K and the like.

Further optimizing the technical scheme, the cocoyl monoethanolamine is obtained by the reaction of coconut oil and monoethanolamine.

Further optimizing the technical scheme, the polyether carbon chain, the alkyl sulfonate, the cocoyl monoethanolamine and the fatty alcohol phenyl vinyl ether are nonionic surfactants.

Compared with the prior art, the invention has the following advantages:

1. the cocoyl monoethanolamine not only has the function of an oil displacement surfactant, but also is a good dispersing agent for calcium and magnesium ions, and the influence of easy corrosion and easy attachment ions is prevented;

2. the oil displacement effect of the surfactant is enhanced and the surfactant is easier to store by using a plurality of oil displacement organic matters in a mixed way;

3. the PH value of the mixture is kept between 8 and 9, the hydrolysis of sulfonic acid groups is prevented in a weak alkaline environment, the constant content of the sulfonic acid groups and metal ions in the mixed solution is ensured, and the retention time of the active agent is prolonged;

4. the use of polyether carbon chains and fatty alcohol phenyl vinyl ether enables the mixture to contain a large amount of hydroxyl groups and ether bonds, so that the mixture is more hydrophilic, and the oil displacement effect is achieved.

Drawings

FIG. 1 is a schematic diagram of the oil displacement effect of an environmentally-friendly viscoelastic wetting surfactant for oil displacement and the preparation method thereof when the polyether carbon chain and the fatty alcohol phenyl vinyl ether are in different proportions.

Fig. 2 shows the influence of cocoyl monoethanolamine on an active agent and the influence of calcium and magnesium ion dispersion efficiency of a viscoelastic wetting surfactant for environmental oil displacement and a preparation method thereof.

Fig. 3 is a schematic diagram of the addition amount of alkyl sulfonate to the oil displacement wetting effect of an active agent in an environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof.

FIG. 4 is a schematic diagram showing the influence of the mixture PH of the viscoelastic wetting surfactant for environmental oil displacement and the preparation method thereof on the wetting effect, the oil displacement efficiency and the viscoelastic index of the surfactant.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

Example 1

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized in that: the main raw materials are as follows: alkyl alcohols, fatty alcohols, phenyl vinyl alcohol, and the like; the gas raw materials are as follows: sulfur dioxide; the apparatus used comprises: a reaction kettle and an oxygen generator.

The main components are as follows: polyether carbon chains and fatty alcohol phenyl vinyl ethers.

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized by comprising the following steps:

(1) preparing fatty alcohol phenyl vinyl ether: dropwise adding concentrated sulfuric acid into phenyl vinyl alcohol, uniformly stirring, heating to 150 ℃ and 170 ℃, and then adding a proper amount of catalyst to generate phenyl vinyl ether; reducing the temperature of the reaction solution to about 60 ℃, adding fatty alcohol and a catalyst into the reaction solution, and reacting for 2 hours to obtain fatty alcohol phenyl vinyl ether for later use;

(2) and (3) sequentially dripping 50-80% of polyether carbon chain and 20-50% of fatty alcohol phenyl vinyl ether in the prepared experimental reagent into the reaction kettle according to the proportion, and stirring for 2-3h to obtain the viscoelastic wetting surfactant for oil displacement.

The polyether carbon chain is a chain molecule containing 12 to 21 carbon atoms.

The polyether carbon chain and the fatty alcohol phenyl vinyl ether are nonionic surfactants.

Example 2

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized in that: the main raw materials are as follows: coconut oil, monoethanolamine, alkyl alcohol, fatty alcohol, phenyl vinyl alcohol, and the like; the gas raw materials are as follows: sulfur dioxide; the apparatus used comprises: a reaction kettle and an oxygen generator.

The main components are as follows: polyether carbon chain, alkyl sulfonate, cocoyl monoethanolamine and fatty alcohol phenyl vinyl ether.

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized by comprising the following steps:

(1) preparing fatty alcohol phenyl vinyl ether: dropwise adding concentrated sulfuric acid into phenyl vinyl alcohol, uniformly stirring, heating to 150 ℃ and 170 ℃, and then adding a proper amount of catalyst to generate phenyl vinyl ether; reducing the temperature of the reaction solution to about 60 ℃, adding fatty alcohol and a catalyst into the reaction solution, and reacting for 2 hours to obtain fatty alcohol phenyl vinyl ether for later use;

(2) uniformly mixing polyether carbon chains and fatty alcohol phenyl vinyl ether in proportion to obtain a mixture A;

(3) and (3) sequentially dripping the prepared mixture A of 20-80% of the experimental reagent and 20-80% of the cocoyl monoethanolamine into the reaction kettle according to the proportion, uniformly stirring, and obtaining the viscoelastic wetting surfactant for oil displacement after 2-3 h.

The polyether carbon chain is a chain molecule containing 12 to 21 carbon atoms.

The coconut monoethanol amine is obtained by the reaction of coconut oil and monoethanol amine.

The polyether carbon chain, the cocoyl monoethanolamine and the fatty alcohol phenyl vinyl ether are nonionic surfactants.

Example 3

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized in that: the main raw materials are as follows: coconut oil, monoethanolamine, alkyl alcohol, fatty alcohol, phenyl vinyl alcohol, and the like; the gas raw materials are as follows: sulfur dioxide; the apparatus used comprises: a reaction kettle and an oxygen generator.

The main components are as follows: polyether carbon chain, alkyl sulfonate, cocoyl monoethanolamine and fatty alcohol phenyl vinyl ether.

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized by comprising the following steps:

(1) preparing 5 to 10 percent of alkyl sulfonate: firstly, introducing sulfur dioxide and excessive oxygen into a reactor, adding a catalyst, and completely oxidizing the sulfur dioxide into sulfur trioxide; conveying sulfur trioxide into a reactor filled with alkyl alcohol, starting a stirrer, keeping the temperature of the reactor at 40-60 ℃, adding 1, 2-dihydroxypentanol, adjusting the pH of a reaction solution to about 4-5, and reacting for 1h under an acidic condition; continuously dropwise adding 5% sodium hydroxide aqueous solution to enable the pH of the alkyl sulfonate in the reactor to be 8-9, and enabling the alkyl sulfonic acid to react with sodium ions under the condition of a catalyst to obtain the alkyl sulfonate for later use;

(2) preparing fatty alcohol phenyl vinyl ether: dropwise adding concentrated sulfuric acid into phenyl vinyl alcohol, uniformly stirring, heating to 150 ℃ and 170 ℃, and then adding a proper amount of catalyst to generate phenyl vinyl ether; reducing the temperature of the reaction solution to about 60 ℃, adding fatty alcohol and a catalyst into the reaction solution, and reacting for 2 hours to obtain fatty alcohol phenyl vinyl ether for later use;

(3) mixing the mixture A and the cocoyl monoethanolamine according to a proportion to obtain a mixture B;

(4) 5-10 parts of an alkyl sulfonate solution with the content of 5% -10% is added into the prepared experimental reagent B mixture, the mixture is uniformly stirred, and the viscoelastic wetting surfactant for oil displacement can be obtained after 2-3 hours.

The polyether carbon chain is a chain molecule containing 12 to 21 carbon atoms.

The molecular formula of the alkyl sulfonate is R1R2M structure; the R1 is alkyl or alkyl carbon chain structure; the R1 contains 12 to 20 carbon atoms; r2 is a sulfonic acid group; and M is active metal such as metal ions Na or K and the like.

The coconut monoethanol amine is obtained by the reaction of coconut oil and monoethanol amine.

The polyether carbon chain, the alkyl sulfonate, the cocoyl monoethanolamine and the fatty alcohol phenyl vinyl ether are nonionic surfactants.

Example 4

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized in that: the main raw materials are as follows: coconut oil, monoethanolamine, alkyl alcohol, fatty alcohol, phenyl vinyl alcohol, and the like; the gas raw materials are as follows: sulfur dioxide; the apparatus used comprises: a reaction kettle and an oxygen generator.

The main components are as follows: polyether carbon chain, alkyl sulfonate, cocoyl monoethanolamine and fatty alcohol phenyl vinyl ether.

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized by comprising the following steps:

(1) preparing 5 to 10 percent of alkyl sulfonate: firstly, introducing sulfur dioxide and excessive oxygen into a reactor, adding a catalyst, and completely oxidizing the sulfur dioxide into sulfur trioxide; conveying sulfur trioxide into a reactor filled with alkyl alcohol, starting a stirrer, keeping the temperature of the reactor at 40-60 ℃, adding 1, 2-dihydroxypentanol, adjusting the pH of a reaction solution to about 4-5, and reacting for 1h under an acidic condition; continuously dropwise adding 5% sodium hydroxide aqueous solution to enable the pH of the alkyl sulfonate in the reactor to be 8-9, and enabling the alkyl sulfonic acid to react with sodium ions under the condition of a catalyst to obtain the alkyl sulfonate for later use;

(2) preparing fatty alcohol phenyl vinyl ether: dropwise adding concentrated sulfuric acid into phenyl vinyl alcohol, uniformly stirring, heating to 150 ℃ and 170 ℃, and then adding a proper amount of catalyst to generate phenyl vinyl ether; reducing the temperature of the reaction solution to about 60 ℃, adding fatty alcohol and a catalyst into the reaction solution, and reacting for 2 hours to obtain fatty alcohol phenyl vinyl ether for later use;

(3) mixing the mixture A and the cocoyl monoethanolamine according to a proportion to obtain a mixture B;

(4) and adding 10-15 parts of 5% -10% alkyl sulfonate solution into the prepared experimental reagent B mixture, uniformly stirring, and obtaining the viscoelastic wetting surfactant for oil displacement after 2-3 hours.

The polyether carbon chain is a chain molecule containing 12 to 21 carbon atoms.

The molecular formula of the alkyl sulfonate is R1R2M structure; the R1 is alkyl or alkyl carbon chain structure; the R1 contains 12 to 20 carbon atoms; r2 is a sulfonic acid group; and M is active metal such as metal ions Na or K and the like.

The coconut monoethanol amine is obtained by the reaction of coconut oil and monoethanol amine.

The polyether carbon chain, the alkyl sulfonate, the cocoyl monoethanolamine and the fatty alcohol phenyl vinyl ether are nonionic surfactants.

Example 5

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized in that: the main raw materials are as follows: coconut oil, monoethanolamine, alkyl alcohol, fatty alcohol, phenyl vinyl alcohol, and the like; the gas raw materials are as follows: sulfur dioxide; the apparatus used comprises: a reaction kettle and an oxygen generator.

The main components are as follows: polyether carbon chain, alkyl sulfonate, cocoyl monoethanolamine and fatty alcohol phenyl vinyl ether.

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized by comprising the following steps:

(1) preparing 5 to 10 percent of alkyl sulfonate: firstly, introducing sulfur dioxide and excessive oxygen into a reactor, adding a catalyst, and completely oxidizing the sulfur dioxide into sulfur trioxide; conveying sulfur trioxide into a reactor filled with alkyl alcohol, starting a stirrer, keeping the temperature of the reactor at 40-60 ℃, adding 1, 2-dihydroxypentanol, adjusting the pH of a reaction solution to about 4-5, and reacting for 1h under an acidic condition; continuously dropwise adding 5% sodium hydroxide aqueous solution to enable the pH of the alkyl sulfonate in the reactor to be 8-9, and enabling the alkyl sulfonic acid to react with sodium ions under the condition of a catalyst to obtain the alkyl sulfonate for later use;

(2) preparing fatty alcohol phenyl vinyl ether: dropwise adding concentrated sulfuric acid into phenyl vinyl alcohol, uniformly stirring, heating to 150 ℃ and 170 ℃, and then adding a proper amount of catalyst to generate phenyl vinyl ether; reducing the temperature of the reaction solution to about 60 ℃, adding fatty alcohol and a catalyst into the reaction solution, and reacting for 2 hours to obtain fatty alcohol phenyl vinyl ether for later use;

(3) mixing the mixture A and the cocoyl monoethanolamine according to a proportion to obtain a mixture B;

(4) 15-25 parts of an alkyl sulfonate solution with the content of 5% -10% is added into the prepared experimental reagent B mixture, the mixture is uniformly stirred, and the viscoelastic wetting surfactant for oil displacement can be obtained after 2-3 hours.

The polyether carbon chain is a chain molecule containing 12 to 21 carbon atoms.

The molecular formula of the alkyl sulfonate is R1R2M structure; the R1 is alkyl or alkyl carbon chain structure; the R1 contains 12 to 20 carbon atoms; r2 is a sulfonic acid group; and M is active metal such as metal ions Na or K and the like.

The coconut monoethanol amine is obtained by the reaction of coconut oil and monoethanol amine.

The polyether carbon chain, the alkyl sulfonate, the cocoyl monoethanolamine and the fatty alcohol phenyl vinyl ether are nonionic surfactants.

Example 6

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized in that: the main raw materials are as follows: coconut oil, monoethanolamine, alkyl alcohol, fatty alcohol, phenyl vinyl alcohol, and the like; the gas raw materials are as follows: sulfur dioxide; the apparatus used comprises: a reaction kettle and an oxygen generator.

The main components are as follows: polyether carbon chain, alkyl sulfonate, cocoyl monoethanolamine, fatty alcohol phenyl vinyl ether and 0.5-1% sodium hydroxide aqueous solution.

An environment-friendly viscoelastic wetting surfactant for oil displacement and a preparation method thereof are characterized by comprising the following steps:

(1) preparing 0.5% -1% sodium hydroxide aqueous solution: firstly weighing 5-10g of sodium hydroxide solid powder, dissolving the sodium hydroxide solid powder in a beaker filled with distilled water, uniformly stirring, then pouring the sodium hydroxide solid powder into a 1L volumetric flask, washing the beaker for multiple times, pouring washing liquid into the volumetric flask, and fixing the volume for later use;

(2) preparing 5 to 10 percent of alkyl sulfonate: firstly, introducing sulfur dioxide and excessive oxygen into a reactor, adding a catalyst, and completely oxidizing the sulfur dioxide into sulfur trioxide; conveying sulfur trioxide into a reactor filled with alkyl alcohol, starting a stirrer, keeping the temperature of the reactor at 40-60 ℃, adding 1, 2-dihydroxypentanol, adjusting the pH of a reaction solution to about 4-5, and reacting for 1h under an acidic condition; continuously dropwise adding 5% sodium hydroxide aqueous solution to enable the pH of the alkyl sulfonate in the reactor to be 8-9, and enabling the alkyl sulfonic acid to react with sodium ions under the condition of a catalyst to obtain the alkyl sulfonate for later use;

(3) preparing fatty alcohol phenyl vinyl ether: dropwise adding concentrated sulfuric acid into phenyl vinyl alcohol, uniformly stirring, heating to 150 ℃ and 170 ℃, and then adding a proper amount of catalyst to generate phenyl vinyl ether; reducing the temperature of the reaction solution to about 60 ℃, adding fatty alcohol and a catalyst into the reaction solution, and reacting for 2 hours to obtain fatty alcohol phenyl vinyl ether for later use;

(4) mixture B and mixture C with% alkyl sulfonate in proportion;

(5) and (3) dropwise adding a proper amount of 0.5-1% aqueous solution of sodium hydroxide into the mixture C, adjusting the pH value to 8-9, and stirring for 2-3h to obtain the viscoelastic wetting surfactant for oil displacement.

The polyether carbon chain is a chain molecule containing 12 to 21 carbon atoms.

The molecular formula of the alkyl sulfonate is R1R2M structure; the R1 is alkyl or alkyl carbon chain structure; the R1 contains 12 to 20 carbon atoms; r2 is a sulfonic acid group; and M is active metal such as metal ions Na or K and the like.

The coconut monoethanol amine is obtained by the reaction of coconut oil and monoethanol amine.

The polyether carbon chain, the alkyl sulfonate, the cocoyl monoethanolamine and the fatty alcohol phenyl vinyl ether are nonionic surfactants.

In summary, as shown in the data in fig. 1, when the ratio of the polyether carbon chain to the fatty alcohol phenyl vinyl ether in the mixture is changed, the oil displacement effect of the mixture is constantly changed, when the content of the polyether carbon chain in the mixture gradually increases and the content of the fatty alcohol phenyl vinyl ether in the mixture gradually decreases, the oil displacement efficiency of the mixture gradually increases, and when the ratio of the polyether carbon chain to the fatty alcohol phenyl vinyl ether is 7:3, and when the content of the polyether carbon chain in the mixture is increased, the oil displacement effect is slightly reduced. Therefore, when hydroxyl and ether bonds in the mixture are increased, the hydrophilicity of the mixture is improved, and the oil displacement effect of the mixture is improved.

The data in figure 2 show that the coconut oil acyl monoethanolamine with a proper amount is added into the mixture, so that the oil displacement effect of the mixture is improved to a certain extent, and the coconut oil acyl monoethanolamine has strong dispersing capacity for calcium and magnesium ions, so that the efficiency of equipment exploitation is indirectly improved.

The data in figure 3 show that the alkyl sulfonate can remarkably increase the oil displacement efficiency of the mixture, and when the addition amount of the alkyl sulfonate is 10-15 parts, the oil displacement effect reaches the optimal state; and the alkyl sulfonate has a certain wetting effect, so that the contact effect between equipment and a rock stratum is better during exploitation.

The data in figure 4 show that the PH of the mixture is changed by adding sodium hydroxide solution dropwise, experimental data show that the PH has a certain auxiliary effect on the wetting effect, the oil displacement efficiency and the visco-elastic index of the mixture, and when the PH of the mixture reaches 8-9, the wetting effect, the oil displacement efficiency and the visco-elastic index all reach the optimal states.

It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.