CN114456077A - A kind of asymmetric geminal betaine viscoelastic surfactant and its preparation method and application - Google Patents

Abstract

The invention relates to the technical field of viscoelastic surfactants, in particular to an asymmetric twin-tail betaine viscoelastic surfactant as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) uniformly mixing epoxy chloroalkane and long-chain tertiary amine for reaction, and distilling, crystallizing and drying a reaction product to obtain an intermediate mono-quaternary ammonium salt; (2) in the presence of a solvent, the intermediate mono-quaternary ammonium salt reacts with alkenyl succinic anhydride to obtain a reaction productRemoving the solvent, and cooling to room temperature to obtain a paste, namely the viscoelastic surfactant. The product of the invention has an asymmetric structure, particularly unsaturated bonds are introduced, the gelling capability of the surfactant in an alkaline environment is improved, the alkali resistance value reaches pH 8 or above, the surface tension is lower than 38mN/m, and the critical micelle concentration is lower than 1.6 x 10^‑6mol/ml。

Description

A kind of asymmetric geminal betaine viscoelastic surfactant and its preparation method and application

technical field

The invention relates to the technical field of viscoelastic surfactants, in particular to an asymmetric geminal betaine viscoelastic surfactant and a preparation method and application thereof.

Background technique

Viscoelastic Surfactant (VES) has the advantages of easy biodegradation, no organic solvent, green environmental protection, safe use, small molecular weight, easy flowback, and will not cause damage to the formation. Because of its advantages in rheology, it is favored by researchers at home and abroad. At present, the domestic VES research focuses on the temperature resistance, acid resistance and salt resistance performance of VES fracturing fluid.

CN108102637A discloses a viscoelastic surfactant weighted fracturing fluid and a configuration method thereof. The weight composition of the weighted fracturing fluid is as follows: 2-5% of viscoelastic surfactant in isopropanol solution, 20-40% of weighting agent %, hydrochloric acid 0.1-1%, the rest is water. The configuration method is as follows: separately prepare the A component as the base liquid and the B component as the crosslinking agent, wherein the mass ratio of the A component: 1% of the isopropanol solution of the viscoelastic surfactant, 20-40% of the weighting agent %, hydrochloric acid 0.1-1%, and the rest is water; component B is 1-4% viscoelastic surfactant solution in isopropanol, and then component A and component B are mixed to obtain. The fracturing fluid has a density of 1.15-1.42 g/cm ³ , and the density is greatly increased, and at the same time meets the on-site construction requirements of the fracturing fluid. The viscoelastic surfactant is simple to produce, instantly dissolves in liquid, can be quickly deployed on the construction site, has good temperature resistance and shear resistance, and can automatically break glue when encountering oil and gas in the formation.

CN109337664A discloses an oligomeric configuration viscoelastic surfactant, a synthesis method and a thickening acid formula. The oligomeric configuration viscoelastic surfactant of the present invention firstly uses organic amines and halogenated alkanes as main raw materials to synthesize a quaternary amine salt-containing polyhalogenated alkane intermediate; and then adds a tertiary amine to the synthetic product of the first step to continue the synthetic reaction to obtain Quaternary ammonium salt cationic viscoelastic surfactant in oligomeric configuration. The oligomeric configuration viscoelastic surfactant of the present invention can replace the existing viscoelastic surfactant in the field of oil recovery engineering, has a plurality of quaternary ammonium salt cations on the connecting groups distributed in the comb shape, has a high degree of polymerization, and effectively reduces the The critical micelle concentration has better thickening, anti-swelling, and drainage effects, making the rock more water-wet, and the surfactant structure does not contain amide bonds, which can effectively avoid decomposition under strong acid conditions and improve the oilfield acidification industry. scope of use.

CN109536155A discloses a salt-tolerant gemini cationic viscoelastic surfactant, a preparation method thereof, and a salt-tolerant clean fracturing fluid. The salt-tolerant gemini cationic viscoelastic surfactant of the present invention is composed of fatty acid amidopropyl dimethylamine and Dibromoneopentyl glycol is synthesized as raw material. It can form micelles in seawater or formation water with high salinity, so that the solution exhibits good viscoelasticity. /L or more, it can be used to configure seawater-based clean fracturing fluid, and at the same time avoid gel breaking after encountering formation water with high salinity; and it can also be used to configure seawater-based clean fracturing fluid, with a maximum salinity of 200000mg/L. The preparation method of the invention is simple, the yield of the product is greatly improved, generally reaching more than 96%, and the reaction has few by-products and has little influence on the performance of the product. When preparing clean fracturing fluid, the amount of it is reduced and the cost is reduced.

The viscoelastic surfactants (VES) mentioned above have temperature resistance, acid resistance and salt resistance, respectively, but none of them have alkali resistance. However, the formation conditions are complex and changeable. For example, the Linnan Oilfield of the Linpan Oil Production Plant of Shengli Oilfield needs to inject weak alkaline water during development. Therefore, it is of great significance to develop an alkali-resistant VES suitable for complex formations.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the prior art, the present invention provides an asymmetric geminal betaine viscoelastic surfactant and a preparation method thereof. The surfactant not only has strong gel-forming ability under alkaline conditions, but also has relatively high viscosity.

According to the first aspect of the present invention, the present invention provides a kind of asymmetrical gemini betaine viscoelastic surfactant, and described viscoelastic surfactant structural formula is:

Wherein: n=1, 2, preferably n=1;

R ₁ is an alkyl group of C _4-8 , preferably a normal alkyl group of C _5-6 ;

R ₂ is an alkyl group of C _2-10 , preferably a normal alkyl group of C _4-6 ;

R ₃ is a C _2-8 alkyl group, preferably a C _3-5 normal alkyl group.

According to the second aspect of the present invention, the present invention provides a preparation method of the asymmetric geminal betaine viscoelastic surfactant described in the first aspect of the present invention, the preparation method comprising:

(1) mixing epichlorohydrin and long-chain tertiary amine uniformly and reacting to obtain reaction product, and reaction product obtains intermediate monoquaternary ammonium salt through distillation, crystallization and drying;

(2) In the presence of a solvent, the above-mentioned intermediate monoquaternary ammonium salt and alkenyl succinic anhydride react, and the reaction product, after removing the solvent, is cooled to room temperature to obtain a paste, which is a viscoelastic surfactant.

According to a third aspect of the present invention, the present invention provides the application of the viscoelastic surfactant according to the first aspect of the present invention as an oil displacement agent or a fracturing fluid in reservoir development.

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

(1) the present invention has simple and easy-to-obtain reaction raw materials, short reaction time, and mild reaction conditions;

(2) The structure of the product of the present invention is asymmetric, especially the introduction of unsaturated bonds, which improves the ability of the surfactant to form gel in an alkaline environment, the alkali resistance value reaches pH=8 and above, and the surface tension is low At 38 mN/m, the critical micelle concentration was lower than 5.0×10 ^-6 mol/ml.

Description of drawings

Fig. 1 is the hydrogen NMR spectrogram of the asymmetric geminal betaine viscoelastic surfactant of embodiment 3 gained;

Fig. 2 is the alkali resistance graph of the asymmetric geminal betaine viscoelastic surfactant obtained in Example 3.

Fig. 3 is the viscosity test curve of the asymmetric geminal betaine viscoelastic surfactant obtained in Example 3.

Detailed ways

The endpoints of ranges and any values disclosed herein are not limited to the precise ranges or values, which are to be understood to encompass values proximate to those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein.

According to the first aspect of the present invention, the present invention provides a kind of asymmetrical gemini betaine viscoelastic surfactant, and described viscoelastic surfactant structural formula is:

Wherein: n=1, 2, preferably n=1;

R ₁ is an alkyl group of C _4-8 , preferably a normal alkyl group of C _5-6 ;

R ₂ is an alkyl group of C _2-10 , preferably a normal alkyl group of C _4-6 ;

R ₃ is a C _2-8 alkyl group, preferably a C _3-5 normal alkyl group.

According to the second aspect of the present invention, the present invention provides a preparation method of the asymmetric geminal betaine viscoelastic surfactant described in the first aspect of the present invention, the preparation method comprising:

(1) mixing epichlorohydrin and long-chain tertiary amine uniformly and reacting to obtain reaction product, and reaction product obtains intermediate monoquaternary ammonium salt through distillation, crystallization and drying;

(2) In the presence of a solvent, the above-mentioned intermediate monoquaternary ammonium salt and alkenyl succinic anhydride react, and the reaction product, after removing the solvent, is cooled to room temperature to obtain a paste, which is a viscoelastic surfactant.

In the present invention, preferably, the general structural formula of described epichlorohydrin is as follows:

Wherein: n=1, 2, preferably n=1.

In the present invention, preferably, the general structural formula of the long-chain tertiary amine is as follows:

Among them, R ₁ is a C _4-8 alkyl group, preferably a C _5-6 normal alkyl group.

In the present invention, preferably, the general structural formula of described alkenyl succinic anhydride is as follows:

Wherein, R ₂ is a C _2-10 alkyl group, preferably a C _4-6 normal alkyl group;

R ₃ is a C _2-8 alkyl group, preferably a C _3-5 normal alkyl group.

The general structural formula of the described intermediate monoquaternary ammonium salt is as follows:

Wherein: n=1, 2, preferably n=1;

R ₁ is a C _4-8 alkyl group, preferably a C _5-6 normal alkyl group.

In the present invention, preferably, the molar ratio of epichlorohydrin, long-chain tertiary amine and alkenyl succinic anhydride is 1:(1-1.05):(1-1.05), more preferably 1:1.02:1.02 .

Preferably, in step (1), the reaction conditions are a temperature of 70-80°C, a reaction time of 1-3h, and a stirring speed of 100-300rpm, more preferably a temperature of 70-75°C, a reaction time of 2-3h, and a stirring speed of 100 rpm. -200rpm.

Preferably, in step (1), the distillation is vacuum distillation; the crystallization times are 3-5 times, and the material used is one of acetone, ethanol, and methanol, more preferably acetone.

In the present invention, preferably, in step (1), the drying is vacuum drying, and the drying temperature is 90-95°C.

Preferably, in step (2), the reaction conditions are a temperature of 75-85°C, a reaction time of 2-5h, and a stirring speed of 300-500rpm, more preferably a temperature of 80-85°C, a reaction time of 3-4h, and a stirring speed of 350 rpm. -400rpm.

Preferably, in step (2), the solvent is one of acetonitrile, N,N-dimethylformamide and methanol, more preferably acetonitrile.

According to a more specific preferred embodiment, the preparation method of the viscoelastic surfactant specifically includes the following steps:

(1) add epichlorohydrin to the reaction vessel (such as a three-necked flask), then slowly add the long-chain tertiary amine solution dropwise with a constant pressure dropping funnel, and heat up to 70-80°C after fully mixing under conditions of stirring speed 100-300rpm ℃ to carry out the reaction for 1-3h.

(2) After the reaction, the excess epichlorohydrin was distilled off under reduced pressure, and recrystallized with acetone for 3-5 times to obtain a white powder, which was vacuum-dried at 90-95° C. to obtain the intermediate monoquaternary ammonium salt.

(3) above-mentioned intermediate monoquaternary ammonium salt and alkenyl succinic anhydride are added in reaction vessel (such as there-necked flask), add solvent again, under stirring speed 300-500rpm and temperature of reaction 75-85 ℃ condition, reflux reaction 2- 5h.

(4) After the reaction is completed, the solvent is removed, and the paste is cooled to room temperature to obtain a viscoelastic surfactant.

The viscoelastic surfactant synthesis process is as follows:

According to a third aspect of the present invention, the present invention provides the application of the viscoelastic surfactant described in the first aspect of the present invention as an oil displacement agent or a fracturing fluid in reservoir development.

The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the specific technical features described in the above-mentioned specific embodiments can be combined in any suitable manner under the condition of no contradiction. In order to avoid unnecessary repetition, the present invention has The combination method will not be specified otherwise.

In addition, the various embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the contents disclosed in the present invention.

The present invention will be further described below with reference to specific embodiments.

In the present invention, the devices or devices used are conventional devices or devices known in the art, and they are all commercially available.

In the following examples and comparative examples, all reagents used are chemically pure reagents from commercial sources unless otherwise specified.

Example 1

A kind of asymmetric twin tail betaine viscoelastic surfactant, is characterized in that, its structural formula is as follows:

where: n=1;

R ₁ is n-butane;

R ₂ is ethane;

R ₃ is ethane.

The preparation method of asymmetric geminal betaine viscoelastic surfactant, comprises the following steps:

(1) Add 0.1 mol of epichlorohydrin to a reaction vessel (such as a three-necked flask), and then slowly add 0.1 mol of long-chain tertiary amine solution dropwise with a constant pressure dropping funnel, mix thoroughly, and heat up to 70 °C for reaction for 2 h ;

(2) after the reaction finishes, underpressure distillation removes excess epichlorohydrin, recrystallizes 3 times with acetone to obtain white powder, and vacuum-dries at 95 ° C to obtain intermediate monoquaternary ammonium salt;

(3) gained monoquaternary ammonium salt and 0.1mol alkenyl succinic anhydride are added in reaction vessel (such as there-necked flask), add the N,N-dimethylformamide of 50ml again as solvent, stir, reflux reaction at 75 ℃ 2h.

(4) After the reaction, the N,N-dimethylformamide is removed, and the paste obtained by cooling to room temperature is the obtained product.

The general structural formula of the long-chain tertiary amine is as follows:

Wherein, R ₁ is n-butanyl.

The general structural formula of described alkenyl succinic anhydride is as follows:

Wherein, R ₂ is ethane;

R ₃ is ethane.

Application of the above-mentioned asymmetric twin-tailed betaine viscoelastic surfactant as oil displacement agent or fracturing fluid in reservoir development.

Example 2

A kind of asymmetric twin tail betaine viscoelastic surfactant, is characterized in that, its structural formula is as follows:

where: n=2;

R ₁ is n-butane;

R ₂ is n-butanyl;

R ₃ is n-propanyl.

The preparation method of asymmetric geminal betaine viscoelastic surfactant, comprises the following steps:

(1) Add 0.1 mol of epichlorobutane to the reaction vessel (three-necked flask), then slowly add 0.105 mol of long-chain tertiary amine solution dropwise with a constant pressure dropping funnel, mix thoroughly and heat up to 75°C for 2 hours of reaction ;

(2) after the reaction finishes, underpressure distillation removes excess epichlorohydrin, recrystallizes 3 times with acetone, obtains white powder 90 ℃ of vacuum-drying, obtains intermediate monoquaternary ammonium salt;

(3) adding the gained monoquaternary ammonium salt and 1.05mol alkenyl succinic anhydride into a reaction vessel (such as a three-necked flask), then adding 50ml of acetonitrile as a solvent, stirring, and refluxing for 5h at 85°C;

(4) After the reaction is completed, the acetonitrile is removed, and the paste obtained by cooling to room temperature is the obtained product.

The general structural formula of the long-chain tertiary amine is as follows:

Wherein, R ₁ is n-butanyl.

The general structural formula of described alkenyl succinic anhydride is as follows:

Wherein, R ₂ is n-butanyl;

R ₃ is n-propanyl.

Application of the above-mentioned asymmetric twin-tailed betaine viscoelastic surfactant as oil displacement agent or fracturing fluid in reservoir development.

Example 3

A kind of asymmetric twin tail betaine viscoelastic surfactant, is characterized in that, its structural formula is as follows:

where: n=1;

R ₁ is C ₆ n-hexane group;

R ₂ is n-pentyl;

R ₃ is n-butanyl.

The preparation method of asymmetric geminal betaine viscoelastic surfactant, comprises the following steps:

(1) Add 0.1 mol of epichlorohydrin to a reaction vessel (such as a three-necked flask), then slowly add 0.102 mol of long-chain tertiary amine solution dropwise with a constant pressure dropping funnel, mix thoroughly and heat up to 80°C for 3 hours of reaction ;

(2) after the reaction finishes, underpressure distillation removes excess epichlorohydrin, recrystallizes 5 times with ethanol to obtain white powder, and vacuum-dries at 92 ° C to obtain intermediate monoquaternary ammonium salt;

(3) gained monoquaternary ammonium salt and 1.02mol alkenyl succinic anhydride are added in reaction vessel (such as there-necked flask), then add the N,N-dimethylformamide of 50ml as solvent, stir, reflux reaction at 80 ℃ 3h;

(4) After the reaction, the N,N-dimethylformamide is removed, and the paste obtained by cooling to room temperature is the obtained product.

The general structural formula of the long-chain tertiary amine is as follows:

Wherein, R ₁ is a C ₆ n-hexane group.

The general structural formula of described alkenyl succinic anhydride is as follows:

Wherein, R ₂ is n-pentyl;

R ₃ is n-butanyl.

Described product is the structural formula of asymmetric geminal betaine viscoelastic surfactant as follows:

Application of the above-mentioned asymmetric twin-tailed betaine viscoelastic surfactant as oil displacement agent or fracturing fluid in reservoir development.

Example 4

A kind of asymmetric twin tail betaine viscoelastic surfactant, is characterized in that, its structural formula is as follows:

where: n=2;

R ₁ is n-octyl;

R ₂ is n-hexane group;

R ₃ is n-pentyl.

The preparation method of asymmetric geminal betaine viscoelastic surfactant, comprises the following steps:

(1) Get 0.1mol of epichlorobutane and add it to the reaction vessel (such as a three-necked flask), then slowly add 0.102mol of long-chain tertiary amine solution dropwise with a constant pressure dropping funnel, and then heat up to 80° C. to react after fully mixing 2h;

(2) after the reaction finishes, underpressure distillation removes excess epichlorohydrin, recrystallizes 4 times with ethanol, obtains white powder, 93 ℃ of vacuum-drying, obtains intermediate monoquaternary ammonium salt;

(3) adding the obtained monoquaternary ammonium salt and 1.05mol alkenyl succinic anhydride (ASA) into a reaction vessel (such as a three-necked flask), then adding 25ml of acetonitrile as a solvent, stirring, and refluxing for 4h at 82°C;

(4) After the reaction is completed, the acetonitrile is removed, and the paste obtained by cooling to room temperature is the obtained product.

The general structural formula of the long-chain tertiary amine is as follows:

Wherein, R ₁ is n-octyl.

The general structural formula of described alkenyl succinic anhydride is as follows:

Wherein, R ₂ is n-hexane group;

R ₃ is n-pentyl.

Application of the above-mentioned asymmetric twin-tailed betaine viscoelastic surfactant as oil displacement agent or fracturing fluid in reservoir development.

Example 5

A kind of asymmetric twin tail betaine viscoelastic surfactant, is characterized in that, its structural formula is as follows:

where: n=2;

R ₁ is n-hexane group;

R ₂ is n-octyl;

R ₃ is n-heptyl.

The preparation method of asymmetric geminal betaine viscoelastic surfactant, comprises the following steps:

(1) get 0.1mol of epichlorohydrin and add it to the reaction vessel (such as a three-necked flask), then slowly add 0.103mol of long-chain tertiary amine solution dropwise with a constant pressure dropping funnel, and then heat up to 72° C. to react after fully mixing 1h;

(2) after the reaction was finished, the excess epichlorobutane was removed by vacuum distillation, and recrystallized with methanol 4 times to obtain a white powder, which was dried under vacuum at 92°C to obtain the intermediate monoquaternary ammonium salt;

(3) adding the gained monoquaternary ammonium salt and 0.102mol alkenyl succinic anhydride into a reaction vessel (such as a three-necked flask), then adding 50ml of methanol as a solvent, stirring, and refluxing for 5h at 78°C;

(4) After the reaction is completed, methanol is removed, and the paste obtained by cooling to room temperature is the obtained product.

The general structural formula of the long-chain tertiary amine is as follows:

Wherein, R ₁ is n-hexane group.

The general structural formula of described alkenyl succinic anhydride is as follows:

Wherein, R ₂ is n-octyl;

R ₃ is n-heptyl.

Application of the above-mentioned asymmetric twin-tailed betaine viscoelastic surfactant as oil displacement agent or fracturing fluid in reservoir development.

Example 6

A kind of asymmetric twin tail betaine viscoelastic surfactant, is characterized in that, its structural formula is as follows:

where: n=2;

R ₁ is n-hexane group;

R ₂ is n-decyl;

R ₃ is n-octyl.

The preparation method of asymmetric geminal betaine viscoelastic surfactant, comprises the following steps:

(1) Get 0.1mol of epichlorobutane and add it to the reaction vessel (such as a three-necked flask), then slowly add 0.105mol of long-chain tertiary amine solution dropwise with a constant pressure dropping funnel, and then heat up to 78° C. to react after fully mixing 2h;

(2) after the reaction was finished, the excess epichlorobutane was removed by vacuum distillation, and recrystallized with methanol for 5 times to obtain a white powder, which was vacuum-dried at 90 °C to obtain the intermediate monoquaternary ammonium salt;

(3) adding the obtained monoquaternary ammonium salt and 1.03mol alkenyl succinic anhydride (ASA) into a reaction vessel (such as a three-necked flask), then adding 50ml of methanol as a solvent, stirring, and refluxing for 3h at 80°C;

(4) After the reaction is completed, methanol is removed, and the paste obtained by cooling to room temperature is the obtained product.

The general structural formula of the long-chain tertiary amine is as follows:

Wherein, R ₁ is n-hexane group.

The general structural formula of described alkenyl succinic anhydride is as follows:

Wherein, R ₂ is n-decyl;

R ₃ is n-octyl.

Application of the above-mentioned asymmetric twin-tailed betaine viscoelastic surfactant as oil displacement agent or fracturing fluid in reservoir development.

Test Example 1

The hydrogen NMR spectrum of a kind of asymmetric geminal betaine viscoelastic surfactant obtained in the embodiment 3 of Fig. 1.

1H NMR (300MHz, DMSO): δ12.13(s, 1H), 6.01(s, 1H), 5.48(m, 2H), 5.32(t, 1H), 4.46～4.21(m, 2H), 2.81～2.56 (m, 2H), 2.34 (q, 2H), 2.30 (s, 8H), 1.94 (q, 2H), 1.46-1.28 (m, 18H), 0.96-0.88 (m, 9H), ppm.

It can be seen from Figure 1 that the present invention has successfully prepared an asymmetric geminal betaine viscoelastic surfactant with a target structure.

Test case 2

In order to characterize the gel-forming effect of the synthesized asymmetric geminal betaine viscoelastic surfactant in an alkaline environment, the asymmetric geminal betaine viscoelastic surfactant synthesized in Example 3 was tested at different pH values. The determination of CMC was carried out, and the results are shown in Figure 2.

It can be seen from Figure 2 that at pH=8, the synthesized asymmetric geminal betaine viscoelastic surfactant still has good gel-forming ability, which is because of the existence of double bonds in the surfactant structure, which is very good. improved its alkali resistance.

Test case 3

In order to characterize the gel-forming properties of the asymmetric geminal betaine viscoelastic surfactant in an alkaline environment, the viscosity test of the asymmetric geminal betaine viscoelastic surfactant synthesized in Example 3 was carried out, and the results are shown in Figure 3 shown.

It can be seen from Figure 3 that when the solution concentration is low, the viscosity changes very little with the shear rate. However, when the concentration is >0.1%, the viscoelastic surfactant solution exhibits obvious nonlinear fluid behavior.

Test Example 4

In order to characterize the surface tension of the synthesized asymmetric geminal betaine viscoelastic surfactant in an alkaline environment, the asymmetric geminal betaine viscoelastic surfactant synthesized in Examples 1-6 was tested at pH=8 The measurement of the surface tension was performed, and the results are shown in Table 1.

Table 1 Test results of surface tension of viscoelastic surface activity of asymmetric geminate betaine

It can be seen from Table 1 that the surface tension of the asymmetric geminal betaine viscoelastic surfactant synthesized by the present invention is less than 38mN/m at pH=8 and the concentration is 0.15%, and the minimum is 30.5mN/m.

Test Example 5

In order to characterize the oil displacement efficiency of the asymmetric geminal betaine viscoelastic surfactant in an alkaline environment, the asymmetric geminal betaine viscoelastic surfactant synthesized in Examples 1-6 was subjected to oil flooding. The results are shown in Table 2.

Table 2 Oil flooding effect of asymmetric geminibetaine viscoelastic surfactant

It can be seen from Table 2 that the asymmetric geminal betaine viscoelastic surfactant can effectively enhance the oil recovery. The oil recovery factor of the primary water flooding of the core is less than 50%; after adding the asymmetric twintail betaine viscoelastic surfactant oil displacement agent, the enhanced oil recovery rate of the crude oil is more than 12%, and the highest is 13.0%. The indoor physical model The oil displacement effect is good.

Example 7

The preparation method of asymmetric geminal betaine viscoelastic surfactant, comprising:

(1) mixing epichlorohydrin and long-chain tertiary amine uniformly and reacting to obtain reaction product, and reaction product obtains intermediate monoquaternary ammonium salt through distillation, crystallization and drying;

(2) In the presence of a solvent, the above-mentioned intermediate monoquaternary ammonium salt and alkenyl succinic anhydride react, and the reaction product, after removing the solvent, is cooled to room temperature to obtain a paste, which is a viscoelastic surfactant.

Further, the general structural formula of described epichlorohydrin is as follows:

where: n=1.

Further, the general structural formula of the long-chain tertiary amine is as follows:

Wherein, R ₁ is n-butanyl.

Further, the general structural formula of described alkenyl succinic anhydride is as follows:

Wherein, R ₂ is ethane;

R ₃ is ethane.

Further, the molar ratio of described epichlorohydrin, long-chain tertiary amine and alkenyl succinic anhydride is 1:1:1.

Further, in step (1), the reaction temperature of the reaction is 70° C., the reaction time is 3h, and the stirring speed is 300rpm.

Further, in step (1), the distillation is vacuum distillation; the number of crystallization times is 3, and the material used for crystallization is acetone.

Further, in step (1), the drying is vacuum drying, and the drying temperature is 90°C.

Further, in step (2), the reaction conditions of the reaction are a temperature of 75°C, a reaction time of 5h, and a stirring speed of 500rpm.

In another embodiment, in step (2), the reaction temperature of the reaction is 80° C., the reaction time is 4h, and the stirring speed is 400rpm.

Further, the solvent is acetonitrile.

Application of the above-mentioned asymmetric twin-tailed betaine viscoelastic surfactant as oil displacement agent or fracturing fluid in reservoir development.

Example 8

The preparation method of asymmetric geminal betaine viscoelastic surfactant, comprising:

(1) mixing epichlorohydrin and long-chain tertiary amine uniformly and reacting to obtain reaction product, and reaction product obtains intermediate monoquaternary ammonium salt through distillation, crystallization and drying;

(2) In the presence of a solvent, the above-mentioned intermediate monoquaternary ammonium salt and alkenyl succinic anhydride react, and the reaction product, after removing the solvent, is cooled to room temperature to obtain a paste, which is a viscoelastic surfactant.

Further, the general structural formula of described epichlorohydrin is as follows:

where: n=2.

Further, the general structural formula of the long-chain tertiary amine is as follows:

Wherein, R ₁ is n-hexyl.

Further, the general structural formula of described alkenyl succinic anhydride is as follows:

Wherein, R ₂ is n-butanyl;

R ₃ is n-hexane group.

Further, the molar ratio of described epichlorohydrin, long-chain tertiary amine and alkenyl succinic anhydride is 1:1.05:1.05.

Further, in step (1), the reaction temperature of the reaction is 80° C., the reaction time is 1 h, and the stirring speed is 100 rpm.

Further, in step (1), the distillation is vacuum distillation; the number of crystallization times is 5, and the material used for crystallization is ethanol.

Further, in step (1), the drying is vacuum drying, and the drying temperature is 95°C.

Further, in step (2), the reaction conditions of the reaction are a temperature of 85° C., a reaction time of 2 hours, and a stirring speed of 300 rpm.

In another embodiment, in step (2), the reaction temperature of the reaction is 85° C., the reaction time is 3h, and the stirring speed is 350rpm.

Further, the solvent is N,N-dimethylformamide.

Application of the above-mentioned asymmetric twin-tailed betaine viscoelastic surfactant as oil displacement agent or fracturing fluid in reservoir development.

Example 9

The preparation method of asymmetric geminal betaine viscoelastic surfactant, comprising:

(1) mixing epichlorohydrin and long-chain tertiary amine uniformly and reacting to obtain reaction product, and reaction product obtains intermediate monoquaternary ammonium salt through distillation, crystallization and drying;

(2) In the presence of a solvent, the above-mentioned intermediate monoquaternary ammonium salt and alkenyl succinic anhydride react, and the reaction product, after removing the solvent, is cooled to room temperature to obtain a paste, which is a viscoelastic surfactant.

Further, the general structural formula of described epichlorohydrin is as follows:

where: n=1.

Further, the general structural formula of the long-chain tertiary amine is as follows:

Wherein, R ₁ is n-octyl.

Further, the general structural formula of described alkenyl succinic anhydride is as follows:

Wherein, R ₂ is n-decyl;

R ₃ is n-octyl.

Further, the molar ratio of described epichlorohydrin, long-chain tertiary amine and alkenyl succinic anhydride is 1:1.02:1.02.

Further, in step (1), the reaction temperature of the reaction is 75° C., the reaction time is 2 h, and the stirring speed is 200 rpm.

Further, in step (1), the distillation is vacuum distillation; the number of crystallization times is 4, and the material used for crystallization is methanol.

Further, in step (1), the drying is vacuum drying, and the drying temperature is 92°C.

Further, in step (2), the reaction conditions of the reaction are a temperature of 82° C., a reaction time of 3.5h, and a stirring speed of 360rpm.

Further, the solvent is methanol.

Application of the above-mentioned asymmetric twin-tailed betaine viscoelastic surfactant as oil displacement agent or fracturing fluid in reservoir development.

The above content is a further detailed description of the present invention, and it cannot be considered that the specific embodiments of the present invention are limited to this. Several simple deductions or substitutions should be regarded as belonging to the protection scope of the present invention determined by the submitted claims.

Claims (20)

1. an asymmetric twin tail betaine viscoelastic surfactant, is characterized in that, its structural formula is as follows:

Among them: n=1, 2; R ₁ is an alkyl group of C _4-8 ; R ₂ is an alkyl group of C _2-10 ; R ₃ is a C _2-8 alkyl group. 2. asymmetric geminal betaine viscoelastic surfactant according to claim 1, is characterized in that, its structural formula is as follows:

where: n=1; R ₁ is an alkyl group of C _4-8 ; R ₂ is an alkyl group of C _2-10 ; R ₃ is a C _2-8 alkyl group. 3. asymmetric geminal betaine viscoelastic surfactant according to claim 1, is characterized in that, its structural formula is as follows:

Among them: n=1, 2; R ₁ is a C _5-6 n-alkyl; R ₂ is an alkyl group of C _2-10 ; R ₃ is a C _2-8 alkyl group. 4. asymmetric geminal betaine viscoelastic surfactant according to claim 1, is characterized in that, its structural formula is as follows:

Among them: n=1, 2; R ₁ is an alkyl group of C _4-8 ; R ₂ is an alkyl group of C _2-10 ; R ₃ is a C _3-5 normal alkyl group. 5. asymmetric geminal betaine viscoelastic surfactant according to claim 1, is characterized in that, its structural formula is as follows:

where: n=1; R ₁ is a C _5-6 n-alkyl; R ₂ is a C _4-6 n-alkyl; R ₃ is a C _3-5 normal alkyl group. 6. the preparation method of the asymmetric geminal betaine viscoelastic surfactant described in any one of claim 1-5, is characterized in that, described preparation method comprises: (1) mixing epichlorohydrin and long-chain tertiary amine uniformly and reacting to obtain reaction product, and reaction product obtains intermediate monoquaternary ammonium salt through distillation, crystallization and drying; (2) In the presence of a solvent, the above-mentioned intermediate monoquaternary ammonium salt and alkenyl succinic anhydride react, and the reaction product, after removing the solvent, is cooled to room temperature to obtain a paste, which is a viscoelastic surfactant. 7. according to the preparation method of the described asymmetric geminal betaine viscoelastic surfactant of claim 6, it is characterized in that, the general structural formula of described epichlorohydrin is as follows:

Where: n=1, 2. 8. according to the preparation method of the described asymmetric geminal betaine viscoelastic surfactant of claim 6, it is characterized in that, the general structural formula of described long-chain tertiary amine is as follows:

Wherein, R ₁ is a C _4-8 alkyl group. 9. according to the preparation method of the described asymmetric geminal betaine viscoelastic surfactant of claim 8, it is characterized in that, the general structural formula of described long-chain tertiary amine is as follows:

Wherein, R ₁ is a C _5-6 normal alkyl group. 10. according to the preparation method of the described asymmetric geminal betaine viscoelastic surfactant of claim 6, it is characterized in that, the general structural formula of described alkenyl succinic anhydride is as follows:

wherein, R ₂ is an alkyl group of C _2-10 ; R ₃ is a C _2-8 alkyl group. 11. according to the preparation method of the described asymmetric geminal betaine viscoelastic surfactant of claim 10, it is characterized in that, the general structural formula of described alkenyl succinic anhydride is as follows:

Wherein, R ₂ is a C _4-6 n-alkyl; R ₃ is a C _3-5 normal alkyl group. 12. the preparation method of asymmetric geminal betaine viscoelastic surfactant according to claim 6, is characterized in that, described epichlorohydrin, long-chain tertiary amine and alkenyl succinic anhydride mol ratio are 1:( 1 to 1.05): (1 to 1.05). 13. the preparation method of asymmetric geminal betaine viscoelastic surfactant according to claim 6, is characterized in that, in step (1), the reaction temperature of described reaction is 70-80 ℃, and the reaction times is 1- 3h, the stirring speed is 100-300rpm. 14. The preparation method of the asymmetric geminal betaine viscoelastic surfactant according to claim 13, wherein the reaction conditions are a temperature of 70-75°C, a reaction time of 2-3h, and a stirring speed of 100-200rpm. 15. the preparation method of asymmetrical gemini betaine viscoelastic surfactant according to claim 6, is characterized in that, in step (1), described distillation is underpressure distillation; Crystallization times are 3-5 times, The material used for crystallization is one of acetone, ethanol and methanol. 16. The preparation method of the asymmetric geminal betaine viscoelastic surfactant according to claim 6, characterized in that, in step (1), the drying is vacuum drying, and the drying temperature is 90-95 °C. 17. the preparation method of the asymmetric geminal betaine viscoelastic surfactant according to claim 6, is characterized in that, in step (2), the reaction condition of described reaction is temperature 75-85 ℃, reaction times 2- 5h, stirring speed 300-500rpm. 18. the preparation method of the asymmetric geminal betaine viscoelastic surfactant according to claim 18, is characterized in that, in step (2), the reaction temperature of described reaction is 80-85 ℃, reaction times 3-4h , The stirring speed is 350-400rpm. 19. The preparation method of the asymmetric geminal betaine viscoelastic surfactant according to claim 6, wherein the solvent is one of acetonitrile, N,N-dimethylformamide and methanol. 20. The application of the asymmetric geminal betaine viscoelastic surfactant according to any one of claims 1-5 as oil displacement agent or fracturing fluid in reservoir development.

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