阅读说明：本技术 一种双磺酸基表面活性剂、清洁压裂液及其制备方法 (Bis-sulfonic acid-based surfactant, clean fracturing fluid and preparation method thereof ) 是由 毛金成 徐涛 毛金桦 叶昊 杨小江 林冲 戴思凯 于 2021-01-13 设计创作，主要内容包括：本发明公开了一种双磺酸基表面活性剂、清洁压裂液及其制备方法,以廉价易得的长链叔胺化合物与环氧氯丙烷作为原料,得到中间体A；中间体A与哌嗪-N,N’-二(2-乙磺酸)倍半钠盐进一步通过季胺化反应制得具有双尾的双磺酸基团表面活性剂,该双磺酸基表活剂具有良好的降低表面活性能力,并且制备简单,以其为稠化剂的清洁压裂液具有优良的耐盐、耐温性,最佳产品在120℃、170s～(-1)下的剪切粘度不小于60mPa·s,远大于清洁压裂液现场施工要求25mPa·s,在油田压裂液及提高采收率中具有较好的应用前景。(The invention discloses a disulfonic acid-based surfactant, a clean fracturing fluid and a preparation method thereof, wherein a cheap and easily-obtained long-chain tertiary amine compound and epoxy chloropropane are used as raw materials to obtain an intermediate A; the intermediate A and piperazine-N, N' -di (2-ethanesulfonic acid) sesqui-sodium salt are further subjected to quaternization reaction to prepare the disulfonic acid group surfactant with double tails, the disulfonic acid group surfactant has good capability of reducing the surface activity, the preparation is simple, the clean fracturing fluid taking the disulfonic acid group surfactant as a thickening agent has excellent salt resistance and temperature resistance, and the optimal product is 170s at 120 DEG C ‑1 The shear viscosity is not less than 60 mPa.s, which is much higher than 25 mPa.s required by the site construction of clean fracturing fluid, and the method has good application prospect in the fracturing fluid of oil fields and the improvement of recovery ratio.)

1. A disulfonic acid based surfactant having the general structural formula:

wherein R is an unsaturated hydrocarbon chain having 17 or 21 carbon atoms.

2. The method for preparing the disulfonic acid-based surfactant according to claim 1, which comprises the following steps: step (1): dissolving a long-chain tertiary amine compound and epoxy chloropropane in a solvent, adding hydrochloric acid, and reacting for 14-20 hours at the reaction temperature of 50-80 ℃ to obtain an intermediate A; wherein the molar usage ratio of the long-chain tertiary amine, the epichlorohydrin to the hydrochloric acid is 1.0:1.0: 1.0-1.5;

step (2): and (2) adding the intermediate A prepared in the step (1) and piperazine-N, N' -bis (2-ethanesulfonic acid) sesquisodium salt into a reaction container according to the molar ratio of 1:2-3, uniformly mixing, and carrying out reflux reaction at 65-90 ℃ for 12-20 hours under a closed condition to prepare the disulfonic acid based surfactant.

3. The method for producing the disulfonic acid-based surfactant according to claim 2, wherein the solvent in the step (1) is dimethylformamide, dichloromethane, dimethylsulfoxide, nitromethane, acetonitrile, 1, 4-dioxane or anhydrous ethanol.

4. The method for producing the disulfonic acid-based surfactant according to claim 2, wherein the reaction temperature in the step (1) is 50 ℃ and the reaction time is 16 hours.

5. The method for producing the disulfonic acid-based surfactant according to claim 2, wherein the reaction temperature in the step (2) is 80 ℃ and the reaction time is 12 hours.

6. A clean fracturing fluid characterized by comprising the bis-sulfonic acid-based surfactant according to claim 1 as a thickener.

7. The clean fracturing fluid of claim 6, comprising the following components in mass fraction: 1.2-2.4% of disulfonic acid-based surfactant, 4-6% of salt and the balance of water.

8. The clean fracturing fluid of claim 6, comprising the following components in mass fraction: 2.4% of disulfonic acid-based surfactant, 4% of salt and the balance of water.

9. The clean fracturing fluid of claim 6, wherein the salt is one or a mixture of potassium chloride, sodium chloride, magnesium sulfate, calcium chloride, ammonium chloride, sodium salicylate, and sodium sulfosalicylate.

10. The method for preparing the clean fracturing fluid of any one of claims 6 to 9, comprising the following steps: and (3) adding the salt into the water solution of the disulfonic acid-based surfactant at room temperature, and stirring until the salt is completely dissolved to obtain the clean fracturing fluid.

Technical Field

The invention relates to the technical field of surfactants, in particular to a disulfonic acid surfactant, a clean fracturing fluid and a preparation method thereof.

Background

Clean fracturing fluids, also known as viscoelastic surfactant fracturing fluids (VES) or polymer-free fracturing fluids, are one type of water-based fracturing fluid. The first product (J508w) was introduced by Schlumberger in 1997 and was rapidly released since its introduction into the market. At present, fracturing construction for multiple wells is successfully implemented, good economic benefits are obtained, but the problems of poor salt resistance, high cost and complex preparation process exist in the existing clean fracturing fluid.

Gemini surfactants have a molecular structure similar to the aggregation of two surfactant molecules and are sometimes referred to as gemini surfactants or gemini surfactants. The common surfactant only has one hydrophilic group and one lipophilic group, while the gemini surfactant at least comprises two hydrophilic groups (ionic head groups) and two hydrophobic groups (hydrocarbon chains, carbon silicon chains or fluorocarbon chains), so that the gemini surfactant has high surface activity, and on the other hand, the chemical bond linkage between the two ionic head groups does not destroy the hydrophilicity, thereby providing a basis for the wide application of the gemini surfactant with high surface activity.

Disclosure of Invention

Aiming at the defects or shortcomings, the invention aims to provide a disulfonic acid-based surfactant, a clean fracturing fluid and a preparation method thereof, which can effectively solve the problems of poor salt tolerance, high cost and complex preparation process of the existing clean fracturing fluid system.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a disulfonic acid-based surfactant, which has a structural general formula as shown in the following formula (I):

wherein R is an unsaturated hydrocarbon chain having 17 or 21 carbon atoms.

The invention also provides a preparation method of the disulfonic acid based surfactant, which comprises the following steps:

step (1):

step (2):

step (1): dissolving a long-chain tertiary amine compound and epoxy chloropropane in a solvent, adding hydrochloric acid, and reacting for 14-20 hours at the reaction temperature of 50-80 ℃ to obtain an intermediate A; wherein the molar usage ratio of the long-chain tertiary amine, the epichlorohydrin to the hydrochloric acid is 1.0:1.0: 1.0-1.5;

step (2): adding the intermediate A prepared in the step (1) and piperazine-N, N' -bis (2-ethanesulfonic acid) sesquisodium salt into a reaction container according to the molar ratio of 1:2-3, uniformly mixing, carrying out reflux reaction for 12-20 hours at 65-90 ℃ under a closed condition, recrystallizing in acetone, filtering and drying to obtain the disulfonic acid based surfactant.

Further, the reaction temperature in the step (1) was 50 ℃ and the reaction time was 16 hours.

Further, the solvent in step (1) is dimethylformamide, dichloromethane, dimethyl sulfoxide, nitromethane, acetonitrile, 1, 4-dioxane or absolute ethanol, preferably absolute ethanol.

Further, the reaction temperature in the step (2) was 80 ℃ and the reaction time was 12 hours.

The invention also provides clean fracturing fluid using the disulfonic acid-based surfactant as a thickening agent, which comprises the following components in percentage by mass: 1.2-2.4% of disulfonic acid-based surfactant, 4-6% of salt and the balance of water.

Further, the invention provides a clean fracturing fluid taking a disulfonic acid-based surfactant as a thickening agent, which comprises the following components in percentage by mass: 2.4% of disulfonic acid-based surfactant, 4% of salt and the balance of water.

Further, the salt is one or more of potassium chloride, sodium chloride, magnesium sulfate, calcium chloride, ammonium chloride, sodium salicylate and sodium sulfosalicylate.

The invention also provides a preparation method of the clean fracturing fluid with the disulfonic acid-based surfactant as the thickening agent, which comprises the following steps: and (3) adding the salt into the water solution of the disulfonic acid-based surfactant at room temperature, and stirring until the salt is completely dissolved to obtain the clean fracturing fluid.

The invention has the beneficial effects that:

1. the invention provides a disulfonic acid based surfactant, which takes a piperazine six-membered ring skeleton as a connecting group, and two nitrogen atoms of a piperazine compound are respectively provided with a sulfonic acid group and an unsaturated hydrocarbon chain to obtain a double-tail surfactant with the disulfonic acid groups, so that monomer ions of the two surfactants are connected quite tightly, strong interaction is generated between the hydrocarbon chains, namely, the hydrophobic bonding force between the hydrocarbon chains is enhanced, and the repulsion tendency between the ion head groups is greatly weakened by the chemical bonding force, so that the disulfonic acid based surfactant has higher salt tolerance and excellent viscoelasticity;

2. the invention provides a preparation method of a disulfonic acid-based surfactant, which takes a cheap and easily-obtained long-chain tertiary amine compound and epoxy chloropropane as raw materials to obtain an intermediate A; the intermediate A and piperazine-N, N' -bis (2-ethanesulfonic acid) sesqui-sodium salt are further subjected to quaternization reaction to prepare the target product, the operation of the whole reaction process is simple, the cost is low, the reaction yield is high, and noble metal is not used as a catalyst;

3. the invention provides clean fracturing fluid taking the disulfonic acid-based surfactant as a thickening agent, wherein the dosage of the surfactant in the clean fracturing fluid is only 1.2-2.4%, so that the cost of the clean fracturing fluid is greatly reduced; the clean fracturing fluid has excellent salt resistance, can keep excellent viscoelasticity at the temperature of below 120 ℃, can be used for the yield-increasing transformation of the fracturing fluid of medium and low permeability reservoirs with high mineralization degree, and has good practical application value;

4. the invention provides a preparation method of clean fracturing fluid using disulfonic acid-based surfactant as thickening agent, the whole preparation process is simple, the counterion salt with required mass is only required to be added into the thickening agent aqueous solution with certain concentration and stirred until dissolved, and the problem of complex preparation process of the existing clean fracturing fluid is effectively solved.

Drawings

FIG. 1 is a rheological curve of the clean fracturing fluid prepared in example 1;

FIG. 2 is a rheological curve of the clean fracturing fluid prepared in example 2;

FIG. 3 is a rheological curve of the clean fracturing fluid prepared in example 3;

FIG. 4 is a rheological curve of the clean fracturing fluid prepared in example 4;

fig. 5 is a nuclear magnetic hydrogen spectrum of the disulfonic acid-based surfactant prepared in example 2.

Detailed Description

The present invention is further illustrated by the following specific examples, which are intended to be purely exemplary of the invention and are not intended to be limiting.

Example 1

The disulfonic acid-based surfactant, the clean fracturing fluid and the preparation method thereof provided in this embodiment 1 specifically include the following processes:

the preparation of the disulfonic acid-based surfactant comprises the following steps:

step (1): dissolving oleamide propyl dimethyl tertiary amine (14.669g, 40mmol) and epichlorohydrin (3.7g, 40mmol) in absolute ethyl alcohol, adding hydrochloric acid (1.45g, 40mmol), reacting at 50 ℃ for 16 hours under the protection of nitrogen, and removing solvent ethanol at 45 ℃ by using a rotary evaporator after the reaction is finished to obtain an intermediate A which is light yellow liquid;

step (2): adding the intermediate A (51.52g, 100mmol) prepared in the step (1) and piperazine-N, N' -bis (2-ethanesulfonic acid) sesquisodium salt (134.14g, 200mmol) into a 100ml single-neck flask, adding 100ml ethanol, and refluxing at 70 ℃ for 18 hours; after the reaction was completed, the solvent ethanol was removed by a rotary evaporator at 45 ℃ to obtain a disulfonic acid-based surfactant (yield 78.57%) in the form of a yellow paste.

Preparing a clean fracturing fluid: under the condition of room temperature, adding 4% by mass of potassium chloride into 2.4% by mass of the prepared water solution of the disulfonic acid-based surfactant, and stirring until the disulfonic acid-based surfactant is completely dissolved to obtain the clean fracturing fluid.

Example 2

The disulfonic acid-based surfactant, the clean fracturing fluid and the preparation method thereof provided in this embodiment 2 specifically include the following processes:

step (1): dissolving erucamidopropyl dimethyl tertiary amine (16.908g, 40mmol) and epichlorohydrin (3.7g, 40mmol) in absolute ethyl alcohol, adding hydrochloric acid (1.45g, 40mmol), reacting at 50 ℃ for 16 hours under the protection of nitrogen, and removing solvent ethanol at 45 ℃ by using a rotary evaporator after the reaction is finished to obtain an intermediate A which is light yellow liquid;

step (2): adding the intermediate A (51.52g, 100mmol) prepared in the step (1) and piperazine-N, N' -bis (2-ethanesulfonic acid) sesquisodium salt (134.14g, 200mmol) into a 100ml single-neck flask, adding 100ml ethanol, and refluxing at 70 ℃ for 18 hours; after the reaction, the solvent ethanol was removed by a rotary evaporator at 45 ℃ to obtain the disulfonic acid-based surfactant (yield 80.34%), whose nuclear magnetic characteristic hydrogen spectrum is shown in fig. 5, and which is yellow paste.

Preparing a clean fracturing fluid: and (3) adding sodium chloride with the mass fraction of 4% into the prepared aqueous solution of the disulfonic acid-based surfactant with the mass fraction of 2.4% at room temperature, and stirring until the disulfonic acid-based surfactant is completely dissolved to obtain the clean fracturing fluid.

Example 3

The disulfonic acid-based surfactant, the clean fracturing fluid and the preparation method thereof provided in this embodiment 3 specifically include the following processes:

the preparation of the disulfonic acid-based surfactant comprises the following steps:

step (1): dissolving oleamide propyl dimethyl tertiary amine (14.669g, 40mmol) and epichlorohydrin (3.7g, 40mmol) in absolute ethyl alcohol, adding hydrochloric acid (1.45g, 40mmol), reacting at 50 ℃ for 16 hours under the protection of nitrogen, and removing solvent ethanol at 45 ℃ by using a rotary evaporator after the reaction is finished to obtain an intermediate A which is light yellow liquid;

step (2): adding the intermediate A (51.52g, 100mmol) prepared in the step (1) and piperazine-N, N' -bis (2-ethanesulfonic acid) sesquisodium salt (134.14g, 200mmol) into a 100ml single-neck flask, adding 100ml ethanol, and refluxing at 80 ℃ for 12 hours; after the reaction was completed, the solvent ethanol was removed by a rotary evaporator at 45 ℃ to obtain a disulfonic acid-based surfactant (yield 84.13%) in the form of a yellow paste.

Preparing a clean fracturing fluid: under the condition of room temperature, adding 6% by mass of potassium chloride into 1.2% by mass of the prepared water solution of the disulfonic acid-based surfactant, and stirring until the disulfonic acid-based surfactant is completely dissolved to obtain the clean fracturing fluid.

Example 4

The disulfonic acid-based surfactant, the clean fracturing fluid and the preparation method thereof provided in this embodiment 4 specifically include the following processes:

the preparation of the disulfonic acid-based surfactant comprises the following steps:

step (1): dissolving oleamide propyl dimethyl tertiary amine (14.669g, 40mmol) and epichlorohydrin (3.7g, 40mmol) in absolute ethyl alcohol, adding hydrochloric acid (1.45g, 40mmol), reacting at 50 ℃ for 16 hours under the protection of nitrogen, and removing solvent ethanol at 45 ℃ by using a rotary evaporator after the reaction is finished to obtain an intermediate A which is light yellow liquid;

step (2): adding the intermediate A (51.52g, 100mmol) prepared in the step (1) and piperazine-N, N' -bis (2-ethanesulfonic acid) sesquisodium salt (134.14g, 200mmol) into a 100ml single-neck flask, adding 100ml ethanol, and refluxing at 90 ℃ for 12 hours; after the reaction was completed, the solvent ethanol was removed by a rotary evaporator at 45 ℃ to obtain a disulfonic acid-based surfactant (yield 74.3%) in the form of a yellow paste.

Preparing a clean fracturing fluid: under the condition of room temperature, adding 6% by mass of potassium chloride into 1.2% by mass of the prepared water solution of the disulfonic acid-based surfactant, and stirring until the disulfonic acid-based surfactant is completely dissolved to obtain the clean fracturing fluid.

Experimental example 1

In order to examine the effect of the clean fracturing fluid adopting the disulfonic acid-based surfactant prepared by the invention as a thickening agent, the rheological property of the clean fracturing fluid prepared in the examples 1-4 is tested by statically suspending sand for 2 hours at the temperature of 120 ℃, the kerosene with the mass fraction of 30% is used for carrying out gel breaking and the viscosity of the gel breaking fluid is tested, and the rheological property test results of the clean fracturing fluid prepared in the examples 1-4 are shown in the figures 1-4, wherein three line segments from top to bottom in the figures 1-4 respectively represent the apparent viscosity, the temperature and the shear rate.

As can be seen from FIGS. 1-4, the apparent viscosity of the clean fracturing fluids prepared in examples 1-4 increased and the shear rate decreased with increasing test time at 120 deg.C, both eventually leveled off and eventually reached 170s at 120 deg.C^-1The shear viscosity is not less than 60 mPa.s, which is much higher than 25 mPa.s required by the site construction of the clean fracturing fluid, and the method has good application prospect in the fracturing fluid of the oil field and the improvement of the recovery ratio; and the static suspended sand has no obvious settlement after 2 hours, the viscosity of the gel breaking liquid after the gel is broken by 30 percent kerosene is less than 5mPa & s, which shows that the prepared clean fracturing fluid can keep excellent viscoelasticity below 120 ℃.

The foregoing is merely exemplary and illustrative of the present invention and it is within the purview of one skilled in the art to modify or supplement the embodiments described or to substitute similar ones without the exercise of inventive faculty, and still fall within the scope of the claims.