A kind of environmentally friendly high-efficiency drainage agent and its synthesis method

Abstract

The present invention proposes an environmentally friendly and efficient drainage aid and a synthesis method thereof, and belongs to the technical field of drainage aids. Gemini zwitterionic surfactants, degradable fluorocarbon surfactants, and anionic surfactants are added to oil, heated to 65-70°C, stirred and mixed evenly, water is added dropwise while stirring, and emulsified after the addition is completed to obtain an environmentally friendly and efficient drainage aid. The environmentally friendly and efficient drainage aid prepared by the present invention can be added to the fracturing fluid to effectively reduce surface tension, increase contact angle, thereby reducing capillary resistance, so that the fracturing fluid can be smoothly discharged back to the formation, prevent it from clogging and damaging the formation, improve the reservoir conductivity and increase oil and gas production, and has low cost, convenient operation, high return rate, and broad application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of drainage aids, and in particular to an environmentally friendly and efficient drainage aid and a synthesis method thereof. Background Art

[0002] Fracturing technology has been widely used as a common technology for increasing production and injection in oil fields. Hydraulic fracturing is to pressurize high-energy liquid on the ground into the formation, so that cracks are generated after the formation is compressed, and proppant is added to fill the cracks to improve the conductivity of the cracks, increase the permeability of the reservoir, and increase production. After the fracturing construction is completed, the gel must be broken in time, and the fracturing fluid gel-breaking liquid must be returned and refluxed. Incomplete return of the gel-breaking liquid will lead to a decrease in the permeability of the reservoir, and incomplete gel-breaking will produce residues that block the formation and cause damage to the reservoir.

[0003] The use of drainage aids can effectively reduce the surface tension of liquids, reduce the interfacial tension between liquids and oils, play a role in reducing capillary forces, and make it easier for debonding liquid to flow back. At present, there are many types of drainage aids used at home and abroad, and their performance varies greatly. The main evaluation index is to measure their surface tension and interfacial tension. However, in the actual application of drainage aids, it is inevitable that they will be mixed with other additives.

[0004] Chinese patent application CN105176511A discloses an acid fracturing fluid drainage agent with excellent performance, which is specifically composed of alkyl polyoxyethylene ether surfactant as the main component, fatty acid polyoxyethylene ether as the auxiliary component, and quaternary ammonium salt for compounding, so as to enhance the ability of surfactant to reduce surface tension and oil-water interfacial tension, and add fatty alcohol and methanol at the same time, so as to increase the miscibility of oil and water, or to play the role of sacrificial agent for improving the utilization rate of surface tension. However, the patent has the following problems: (1) the drainage agent uses quaternary ammonium salt, but does not use cosolvent. Considering that the rock surface is usually negatively charged, cationic surfactants are prone to wetting reversal of rock, which hinders the smooth outflow of crude oil. Although quaternary ammonium salt improves the reverse discharge efficiency to a certain extent, the residual quaternary ammonium salt will greatly reduce the crude oil output in the production process; (2) alkylphenol polyoxyethylene ether is a nonionic surfactant, which is very stable to acids, alkalis and oxidants, is not easy to hydrolyze, and has good surface activity, but the concentration of its metabolites is far below the minimum limit of acute toxicity to aquatic organisms, which is unsafe and environmentally friendly.

[0005] Therefore, optimizing the formula of the drainage aid and developing an environmentally friendly and effective drainage aid are of great practical significance. Summary of the invention

[0006] The purpose of the present invention is to provide an environmentally friendly and efficient drainage agent and a synthesis method thereof. Adding the drainage agent to the fracturing fluid can greatly reduce the surface tension, increase the contact angle, thereby reducing the capillary resistance, so that the fracturing fluid can be smoothly discharged from the formation, prevent it from clogging and damaging the formation, improve the reservoir conductivity and increase the oil and gas production. The invention has low cost, convenient operation, high return rate, and has broad application prospects.

[0007] The technical solution of the present invention is achieved in this way:

[0008] The present invention provides a method for preparing an environmentally friendly and efficient drainage aid, comprising the steps of adding a Gemini zwitterionic surfactant, a degradable fluorocarbon surfactant and an anionic surfactant into oil, heating the oil to 65-70° C., stirring and mixing the oil evenly, dripping water while stirring, and emulsifying the oil after the dripping is completed to prepare the environmentally friendly and efficient drainage aid.

[0009] The structural formula of the Gemini zwitterionic surfactant is shown in Formula I:

[0010] Formula I;

[0011] Among them, R 1 , R 2 =C1-C14 alkyl chain; R 3 =C6-C18 alkyl chain;

[0012] The structural formula of the degradable fluorocarbon surfactant is shown in Formula II:

[0013] Formula II;

[0014] Among them, n=4-7, m=3-6.

[0015] As a further improvement of the present invention, the mass ratio of the Gemini zwitterionic surfactant, the degradable fluorocarbon surfactant, the anionic surfactant, the oil and the water is 2-3:3-5:1-2:30-40:100-120.

[0016] As a further improvement of the present invention, the oil is kerosene or petroleum ether, and the anionic surfactant is selected from at least one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium tetradecylbenzene sulfonate, sodium tetradecyl sulfonate, sodium tetradecyl sulfate, sodium hexadecyl sulfonate, sodium hexadecylbenzene sulfonate, sodium hexadecyl sulfate, sodium octadecylbenzene sulfonate, sodium octadecyl sulfate, and sodium octadecyl sulfonate.

[0017] As a further improvement of the present invention, the synthesis method of the Gemini zwitterionic surfactant is as follows:

[0018] S1. 1,3-dichloro-2-propanol and alkyl halide are reacted to obtain intermediate 1, the structure of which is as follows: ; Among them, R 3 =C6-C18 alkyl chain;

[0019] S2. Intermediate 1 is reacted with a disubstituted amine to obtain intermediate 2, the structure of which is as follows: ; Among them, R 1 , R 2 =C1-C14 alkyl chain;

[0020] S3. The intermediate 2 is reacted with propane sultone to obtain the product.

[0021] As a further improvement of the present invention, the alkyl halide in step S1 is selected from at least one of bromhexane, hexyl chloride, heptane bromide, heptane chloride, octane bromide, octane chloride, nonane bromide, nonane chloride, decane bromide, decane chloride, dodecane bromide, dodecane chloride, tetradecane bromide, tetradecane chloride, octadecane bromide, and octadecane chloride; the molar ratio of 1,3-dichloro-2-propanol to the alkyl halide is 1:1-1.1; a base is further added, and the base is selected from at least one of NaOH, KOH, triethylamine, diethylamine, sodium carbonate, and potassium carbonate; the disubstituted amine in step S2 is selected from at least one of N-dodecylmethylamine, N-ethyldodecylamine, N-hexylmethylamine, N-tetradecylmethylamine, N,N-ditetradecylamine, N,N-didodecylamine, and dioctylamine; the molar ratio of the intermediate 1 to the disubstituted amine is 1:2-2.1; the molar ratio of the intermediate 2 to propane sultone in step S3 is 1:2-2.1.

[0022] As a further improvement of the present invention, the synthesis method of the degradable fluorocarbon surfactant is as follows: fluorocarbonic acid and glycol ether are reacted under the action of a catalyst to obtain a product.

[0023] As a further improvement of the present invention, the molar ratio of the fluorocarbonic acid and the glycol ether is 1:1-1.1, the catalyst is concentrated sulfuric acid with a concentration greater than 98%, the reaction temperature is 90-110°C, and the reaction time is 5-7h; the fluorocarbonic acid is selected from at least one of perfluorooctanoic acid, perfluoroheptanoic acid, perfluorohexanoic acid, and perfluoropentanoic acid; the glycol ether is at least one of triethylene glycol ether, tetraethylene glycol ether, tetraethylene glycol ether, and hexaethylene glycol ether.

[0024] The present invention further protects an environmentally friendly and efficient drainage aid prepared by the above preparation method.

[0025] The present invention further protects a Gemini zwitterionic surfactant having a structure as shown in Formula I:

[0026] Formula I;

[0027] Among them, R 1 , R 2 =C1-C14 alkyl chain; R 3 =C6-C18 alkyl chain.

[0028] The present invention further protects a degradable fluorocarbon surfactant having a structure as shown in Formula II:

[0029] Formula II;

[0030] Among them, n=4-7, m=3-6.

[0031] The present invention has the following beneficial effects:

[0032] The present invention prepares a Gemini zwitterionic surfactant, which has the advantages of strong foaming ability, good foam stabilization performance, low surface and interfacial tension, good compatibility with fracturing fluid and acid system, etc. It can not only be compatible with other surfactants to exert a good synergistic effect, but also has a good ability to reduce surface / interfacial tension. The sulfonic acid group structure has good salt and temperature resistance, so that the prepared environmentally friendly and high-efficiency drainage agent has better comprehensive performance and wider application prospects.

[0033] Fluorocarbon surfactants have high surface activity, good thermal stability and chemical stability. They have the "two-increasing" characteristics of being both hydrophobic and oil-increasing, and their ability to reduce oil-water interfacial tension is very strong. They can be compounded with the Gemini zwitterionic surfactants and anionic surfactants of the present invention to produce a good synergistic effect, greatly reduce the amount of surfactants used, and reduce overall costs without affecting the performance of energy products. However, ordinary fluorocarbon surfactants have problems such as difficulty in degradation and persistent bioaccumulation due to their relatively long fluorocarbon chains (C8), and are not safe and environmentally friendly. The present invention obtains a non-ionic fluorocarbon surfactant containing an ester group and an ether group through the esterification reaction of short-chain fluorocarbon acid and ethylene glycol ether, which has good degradation performance, is not easy to cause persistent bioaccumulation, is more green and environmentally friendly, and at the same time, has good salt resistance and temperature resistance.

[0034] The environmentally friendly and efficient drainage aid of the present invention is a uniform microemulsion system with the characteristics of ultra-low interfacial tension, large solubilization ability, small particle size, and good thermodynamic stability. It is not easy to stratify or demulsify, and can reduce the surface tension of the return fluid, the oil-water interfacial tension, and increase the wetting contact angle of the reservoir rock surface, and change the strongly hydrophilic rock surface into a neutral-weakly hydrophilic one, thereby reducing the capillary resistance in the porous medium, increasing the return rate of the residual working fluid, reducing the damage of the working fluid to the formation, and enhancing the production increase and stable production of oil and gas wells.

[0035] The environmentally friendly and efficient drainage aid prepared by the present invention can effectively reduce surface tension and increase contact angle by adding the drainage aid to the fracturing fluid, thereby reducing capillary resistance, allowing the fracturing fluid to be smoothly discharged from the formation, preventing it from clogging and damaging the formation, improving the reservoir conductivity and increasing oil and gas production. The invention has low cost, convenient operation, high return rate and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 The synthetic route of the Gemini zwitterionic surfactant of the present invention is as follows;

[0038] Figure 2 The synthetic route of the degradable fluorocarbon surfactant of the present invention is shown in FIG. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Preparation Example 1 Synthesis of Gemini zwitterionic surfactant

[0041] like Figure 1 , the synthesis method of Gemini zwitterionic surfactant is as follows:

[0042] S1. Dissolve 0.1 mol 1,3-dichloro-2-propanol, 0.1 mol chlorohexane, and 0.3 mol triethylamine in 200 mL dichloromethane, heat under reflux for 3 h, remove the solvent under reduced pressure, and recrystallize under acetone to obtain intermediate 1; ESI-MS calculated value: C 9 H 19 Cl 2 (M+H)+ 197.08, found: 197.1, yield: 95.2%.

[0043] NMR results: 1 H NMR (300 MHz, CDCl 3)δ3.32 (d, 4H), 2.12 (m, 1H), 1.25-1.32 (m, 10H), 0.97 (t, 3H).

[0044] S2. Under nitrogen protection, 0.1 mol of intermediate 1 and 0.2 mol of N-dodecylmethylamine were added to 200 mL of isopropanol, the temperature was raised to 70°C, the reaction was carried out for 7 h, the solvent was removed under reduced pressure, and the intermediate 2 was obtained by recrystallization with a solution of ethyl acetate and ethanol in a volume ratio of 20:1; ESI-MS calculated value: C 35 H 75 N 2 (M+H)+ 435.33, found: 435.3, yield: 84.6%.

[0045] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ2.32-2.36 (m, 8H), 2.27 (s, 6H), 2.14 (m, 1H), 1.27-1.35 (m, 50H), 0.96-0.97 (m, 9H).

[0046] S3. Add 0.1 mol of intermediate 2 and 0.2 mol of propane sultone into 200 mL of acetone, heat to 35°C and react for 20 h, filter, wash the solid, and dry to obtain the product. ESI-MS calculated value: C 41 H 87 N 2 O 6 S 2 (M+H)+ 767.59, found: 767.6, yield: 88.7%.

[0047] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ2.31-2.37 (m, 12H), 2.27 (s, 6H), 2.14 (m, 1H), 1.26-1.42 (m, 58H), 0.96-0.97 (m, 9H).

[0048] Preparation Example 2 Synthesis of Gemini Zwitterionic Surfactant

[0049] like Figure 1 , the synthesis method of Gemini zwitterionic surfactant is as follows:

[0050] S1. Dissolve 0.1 mol 1,3-dichloro-2-propanol, 0.11 mol chloroheptane, and 0.3 mol KOH in 200 mL dichloromethane, heat under reflux for 3 h, remove the solvent under reduced pressure, and recrystallize from acetone to obtain intermediate 1; ESI-MS calculated value: C10 H 21 Cl 2 (M+H)+ 211.09, found: 211.1, yield: 94.8%.

[0051] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ3.31 (d, 4H), 2.11 (m, 1H), 1.27-1.34 (m, 12H), 0.97 (t, 3H).

[0052] S2. Under nitrogen protection, 0.1 mol of intermediate 1 and 0.21 mol of N-hexylmethylamine were added to 200 mL of isopropanol, the temperature was raised to 70°C, the reaction was carried out for 7 h, the solvent was removed under reduced pressure, and the intermediate 2 was obtained by recrystallization with a solution of ethyl acetate and ethanol in a volume ratio of 20:1; ESI-MS calculated value: C 24 H 52 N 2 (M+H)+ 369.41, found: 369.4, yield: 89.4%.

[0053] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ2.32-2.35 (m, 8H), 2.26 (s, 6H), 2.13 (m, 1H), 1.27-1.35 (m, 28H), 0.96-0.98 (m, 9H).

[0054] S3. Add 0.1 mol of intermediate 2 and 0.21 mol of propane sultone into 200 mL of acetone, heat to 35°C and react for 20 h, filter, wash the solid, and dry to obtain the product. ESI-MS calculated value: C 30 H 65 N 2 O 6 S 2 (M+H)+ 613.42, found: 613.4, yield: 92.1%.

[0055] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ2.32-2.36 (m, 12H), 2.28 (s, 6H), 2.12 (m, 1H), 1.26-1.42 (m, 36H), 0.96-0.97 (m, 9H).

[0056] Preparation Example 3 Synthesis of Gemini Zwitterionic Surfactant

[0057] like Figure 1, the synthesis method of Gemini zwitterionic surfactant is as follows:

[0058] S1. Dissolve 0.1 mol 1,3-dichloro-2-propanol, 0.105 mol chlorohexane and 0.3 mol triethylamine in 200 mL dichloromethane, heat under reflux for 3 h, remove the solvent under reduced pressure, and recrystallize from acetone to obtain intermediate 1 with a yield of 95.7%.

[0059] S2. Under nitrogen protection, 0.1 mol of intermediate 1 and 0.205 mol of N-tetradecylmethylamine were added to 200 mL of isopropanol, the temperature was raised to 70°C, the reaction was continued for 7 h, the solvent was removed under reduced pressure, and the intermediate 2 was obtained by recrystallization with a solution of ethyl acetate and ethanol in a volume ratio of 20:1; ESI-MS calculated value: C 39 H 83 N 2 (M+H)+ 579.65, found: 579.7, yield: 87.4%.

[0060] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ2.32-2.37 (m, 8H), 2.26 (s, 6H), 2.12 (m, 1H), 1.27-1.38 (m, 58H), 0.96-0.97 (m, 9H).

[0061] S3. Add 0.1 mol of intermediate 2 and 0.205 mol of propane sultone into 200 mL of acetone, heat to 35°C and react for 20 h, filter, wash the solid, and dry to obtain the product. ESI-MS calculated value: C 45 H 95 N 2 O 6 S 2 (M+H)+ 823.66, found: 823.7, yield: 87.1%.

[0062] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ2.32-2.37 (m, 12H), 2.28 (s, 6H), 2.15 (m, 1H), 1.25-1.45 (m, 66H), 0.96-0.97 (m, 9H).

[0063] Test Example 1

[0064] The critical micelle concentration cmc, surface tension and interfacial tension of the Gemini zwitterionic surfactants prepared in Preparation Examples 1-3 were tested.

[0065] The results are shown in Table 1.

[0066] Table 1

[0067] It can be seen from the above table that the Gemini zwitterionic surfactants prepared in Preparation Examples 1-3 of the present invention have excellent surface / interface properties and low cmc concentrations.

[0068] Preparation Example 4 Synthesis of degradable fluorocarbon surfactant

[0069] like Figure 2 The synthesis method is as follows: 0.1 mol perfluorohexanoic acid and 0.105 mol triethylene glycol ether are dissolved in 200 mL dimethyl sulfoxide, 0.2 mol concentrated sulfuric acid is added dropwise, heated to 100°C, stirred for 6 hours, filtered, the solid is washed, and dried to obtain the product. ESI-MS calculated value: C 12 H 14 F 11 O 5 (M+H)+ 447.06, found: 447.1, yield: 88.5%.

[0070] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ4.27 (t, 2H), 3.65-3.70 (m, 4H), 3.54-3.56 (m, 6H), 2.0 (br, 1H).

[0071] Preparation Example 5 Synthesis of degradable fluorocarbon surfactant

[0072] like Figure 2 The synthesis method is as follows: 0.1 mol perfluorohexanoic acid and 0.1 mol tetraethylene glycol ether are dissolved in 200 mL dimethyl sulfoxide, 0.2 mol concentrated sulfuric acid is added dropwise, heated to 90°C, stirred for 5 hours, filtered, the solid is washed, and dried to obtain the product. ESI-MS calculated value: C 14 H 18 F 11 O 6 (M+H)+ 491.08, found: 491.1, yield: 85.2%.

[0073] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ4.25 (t, 2H), 3.63-3.70 (m, 4H), 3.52-3.57 (m, 10H), 2.0 (br, 1H).

[0074] Preparation Example 6 Synthesis of degradable fluorocarbon surfactant

[0075] like Figure 2 The synthesis method is as follows: 0.1 mol perfluoroheptanoic acid and 0.11 mol tetraethylene glycol ether are dissolved in 200 mL dimethyl sulfoxide, 0.2 mol concentrated sulfuric acid is added dropwise, heated to 110°C, stirred for 7 hours, filtered, the solid is washed, and dried to obtain the product. ESI-MS calculated value: C 15 H 18 F 13 O 6 (M+H)+ 541.08, found: 541.1, yield 84.6%.

[0076] NMR results: 1 H NMR (300 MHz, CDCl 3 )δ4.27 (t, 2H), 3.62-3.71 (m, 4H), 3.52-3.55 (m, 10H), 2.0 (br, 1H).

[0077] Test Example 2

[0078] The critical micelle concentration (cmc), surface tension and interfacial tension at the critical micelle concentration of the degradable fluorocarbon surfactant prepared in Preparation Examples 4-6 were tested.

[0079] The results are shown in Table 2.

[0080] Table 2

[0081] It can be seen from the above table that the degradable fluorocarbon surfactants prepared in Preparation Examples 4-6 of the present invention have excellent surface / interface properties and a low cmc concentration.

[0082] Test Example 3

[0083] The BOD of the degradable fluorocarbon surfactant prepared in Preparation Example 4-6 was tested according to the biodegradability evaluation method in SY / T 6788-2010 "Technical Evaluation Method for Environmental Protection of Water-soluble Oilfield Chemicals". 5 The biodegradability of the samples was tested by HPLC and COD value test, and compared with that of the long fluorocarbon single-chain surfactant FC-4430 (purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.).

[0084] The results are shown in Table 3.

[0085] Table 3

[0086] It can be seen from the above table that the degradable fluorocarbon surfactants prepared in Preparation Examples 4-6 of the present invention are easily biodegradable surfactants, while FC-4430 is a difficult biodegradable surfactant. Example 1

[0087] The present embodiment provides a method for preparing an environmentally friendly and efficient drainage aid, the preparation method comprising: adding 2 parts by weight of the Gemini zwitterionic surfactant prepared in Preparation Example 1, 3 parts by weight of the degradable fluorocarbon surfactant prepared in Preparation Example 4, and 1 part by weight of sodium tetradecylbenzene sulfonate to 30 parts by weight of kerosene, heating to 65°C, stirring and mixing for 25 minutes, adding 100 parts by weight of water dropwise while stirring, and after the addition is completed, emulsifying at 10,000 r / min for 15 minutes to obtain an environmentally friendly and efficient drainage aid. Example 2

[0088] The present embodiment provides a method for preparing an environmentally friendly and efficient drainage aid, the preparation method comprising: adding 3 parts by weight of the Gemini zwitterionic surfactant prepared in Preparation Example 2, 5 parts by weight of the degradable fluorocarbon surfactant prepared in Preparation Example 5, and 2 parts by weight of sodium octadecyl sulfate to 40 parts by weight of petroleum ether, heating to 70°C, stirring and mixing for 25 minutes, adding 120 parts by weight of water dropwise while stirring, and after the addition is completed, emulsifying at 10,000 r / min for 15 minutes to obtain an environmentally friendly and efficient drainage aid. Example 3

[0089] The present embodiment provides a method for preparing an environmentally friendly and efficient drainage aid, the preparation method comprising: adding 2.5 parts by weight of the Gemini zwitterionic surfactant prepared in Preparation Example 3, 4 parts by weight of the degradable fluorocarbon surfactant prepared in Preparation Example 6, and 1.5 parts by weight of sodium dodecyl sulfate to 35 parts by weight of kerosene, heating to 67° C., stirring and mixing for 25 minutes, adding 110 parts by weight of water dropwise while stirring, and after the addition is completed, emulsifying at 10,000 r / min for 15 minutes to obtain an environmentally friendly and efficient drainage aid.

[0090] Comparative Example 1

[0091] Compared with Example 3, the difference is that no Gemini zwitterionic surfactant is added.

[0092] The preparation method comprises: adding 8.4 parts by weight of the degradable fluorocarbon surfactant prepared in Preparation Example 6 and 3.1 parts by weight of sodium dodecyl sulfate into 35 parts by weight of kerosene, heating to 67°C, stirring and mixing for 25 minutes, adding 110 parts by weight of water dropwise while stirring, and after the addition is completed, emulsifying at 10,000 r / min for 15 minutes to obtain an environmentally friendly and efficient drainage agent.

[0093] Comparative Example 2

[0094] Compared with Example 3, the difference is that no degradable fluorocarbon surfactant is added.

[0095] The preparation method comprises: adding 7.2 parts by weight of the Gemini zwitterionic surfactant prepared in Preparation Example 3 and 4.3 parts by weight of sodium dodecyl sulfate into 35 parts by weight of kerosene, heating to 67° C., stirring and mixing for 25 minutes, adding 110 parts by weight of water dropwise while stirring, and after the addition is completed, emulsifying at 10,000 r / min for 15 minutes to obtain an environmentally friendly and efficient drainage agent.

[0096] Comparative Example 3

[0097] Compared with Example 3, the difference is that sodium lauryl sulfate is not added.

[0098] The preparation method comprises: adding 4.42 parts by weight of the Gemini zwitterionic surfactant prepared in Preparation Example 3 and 7.08 parts by weight of the degradable fluorocarbon surfactant prepared in Preparation Example 6 to 35 parts by weight of kerosene, heating to 67°C, stirring and mixing for 25 minutes, adding 110 parts by weight of water dropwise while stirring, and after the addition is completed, emulsifying at 10,000 r / min for 15 minutes to obtain an environmentally friendly and efficient drainage agent.

[0099] Comparative Example 4

[0100] Compared with Example 3, the difference is that only a single Gemini zwitterionic surfactant is added.

[0101] The preparation method comprises: adding 8 parts by weight of the Gemini zwitterionic surfactant prepared in Preparation Example 3 to 35 parts by weight of kerosene, heating to 67° C., stirring and mixing for 25 minutes, adding 110 parts by weight of water dropwise while stirring, and after the addition is completed, emulsifying at 10,000 r / min for 15 minutes to obtain an environmentally friendly and efficient drainage agent.

[0102] Comparative Example 5

[0103] Compared with Example 3, the difference is that only a single degradable fluorocarbon surfactant is added.

[0104] The preparation method comprises: adding 8 parts by weight of the degradable fluorocarbon surfactant prepared in Preparation Example 6 to 35 parts by weight of kerosene, heating to 67°C, stirring and mixing for 25 minutes, adding 110 parts by weight of water dropwise while stirring, and after the addition is completed, emulsifying at 10,000 r / min for 15 minutes to obtain an environmentally friendly and efficient drainage agent.

[0105] Comparative Example 6

[0106] Compared with Example 3, the difference is that only sodium lauryl sulfate is added.

[0107] The preparation method comprises: adding 8 parts by weight of sodium dodecyl sulfate into 35 parts by weight of kerosene, heating to 67°C, stirring and mixing for 25 minutes, dripping 110 parts by weight of water while stirring, and after the dripping is completed, emulsifying at 10000 r / min for 15 minutes to obtain an environmentally friendly and efficient drainage agent.

[0108] Comparative Example 7

[0109] The difference compared with Example 3 is that no emulsification was performed.

[0110] The preparation method comprises: stirring and mixing 2.5 parts by weight of the Gemini zwitterionic surfactant prepared in Preparation Example 3, 4 parts by weight of the degradable fluorocarbon surfactant prepared in Preparation Example 6, 1.5 parts by weight of sodium dodecyl sulfate, 35 parts by weight of kerosene, and 110 parts by weight of water for 10 minutes, heating to 67° C., stirring and mixing for 15 minutes, to prepare an environmentally friendly and efficient drainage agent.

[0111] Test Example 4 Microemulsion Particle Size and Stability Evaluation

[0112] The average particle size of the environmentally friendly and efficient drainage aids prepared in Example 3 and Comparative Example 7 was measured using a BI-200SM-1 dynamic and static laser light scattering instrument. The average particle size after standing for 3 months at room temperature.

[0113] The results are shown in Table 4.

[0114] Table 4

[0115] It can be seen from the above table that the environmentally friendly and efficient drainage agent prepared in Example 3 of the present invention is a microemulsion, has a small average particle size, and has storage stability.

[0116] Test Example 5

[0117] According to the surface tension and interfacial tension evaluation method specified in SY / T 5755-1995 "Performance Evaluation Method of Fracturing and Acidizing Discharge Agents" and Q / SY 1376-2011 "Technical Requirements for Acidizing and Fracturing Discharge Agents", the surface tension and interfacial tension performance tests of the environmentally friendly and efficient discharge agents prepared in Examples 1-3 and Comparative Examples 1-7 were performed, wherein the test concentration was 0.1wt% and the test temperature was 55°C.

[0118] The results are shown in Table 5.

[0119] Table 5

[0120] It can be seen from the above table that the environmentally friendly and efficient drainage aids prepared in Examples 1-3 of the present invention have extremely low surface tension and interfacial tension.

[0121] Test Example 6 Salt Tolerance

[0122] The environmentally friendly and efficient drainage aids (final concentration of 0.1 wt %) prepared in Examples 1-3 and Comparative Examples 1-7 were added to brine with a mineralization of 150 mg / L or 200 mg / L, and the interfacial tension thereof at 55° C. was measured.

[0123] The results are shown in Table 6.

[0124] Table 6

[0125] It can be seen from the above table that the interfacial tension of the environmentally friendly and efficient drainage aids prepared in Examples 1-3 of the present invention does not change much in the salt solution and has good salt resistance.

[0126] Test Example 7

[0127] Referring to SY / T 5755-2016 "Method for evaluating the performance of drainage aids for fracturing acidification", the environmentally friendly and efficient drainage aids prepared in Examples 1-3 and Comparative Examples 1-7 were tested for the drainage rate. Three parallel samples were made for each sample, and the average value was taken to obtain the drainage rate A. The drainage rate of the blank sample was A. 0 . The flowback rate is increased by E.

[0128] The results are shown in Table 7.

[0129] Where, E is the improvement rate of the backflow rate, %; A is the backflow rate of the sample group, %; A 0 , flowback rate of blank sample, %.

[0130] Table 7

[0131] It can be seen from the above table that the environmentally friendly and efficient drainage aids prepared in Examples 1-3 of the present invention have a very high drainage rate and can play a good role in improving the drainage rate.

[0132] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an environmentally friendly and efficient drainage agent. It is characterized in that Adding Gemini zwitterionic surfactant, degradable fluorocarbon surfactant and anionic surfactant to oil, heating to 65-70°C, stirring and mixing evenly, adding water dropwise while stirring, emulsifying after the addition is completed, and preparing an environmentally friendly and efficient drainage agent; the mass ratio of the Gemini zwitterionic surfactant, degradable fluorocarbon surfactant, anionic surfactant, oil and water is 2-3:3-5:1-2:30-40:100-120; The structural formula of the Gemini zwitterionic surfactant is shown in Formula I: Formula I; Among them, R 1 , R 2 =C1-C14 alkyl chain; R 3 =C6-C18 alkyl chain; The structural formula of the degradable fluorocarbon surfactant is shown in Formula II: Formula II; Among them, n=4-7, m=3-6.

2. The preparation method according to claim 1, It is characterized in that The oil is kerosene or petroleum ether, and the anionic surfactant is selected from at least one of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium tetradecylbenzene sulfonate, sodium tetradecyl sulfonate, sodium tetradecyl sulfate, sodium hexadecyl sulfonate, sodium hexadecylbenzene sulfonate, sodium hexadecyl sulfate, sodium octadecylbenzene sulfonate, sodium octadecyl sulfate, and sodium octadecyl sulfonate.

3. The preparation method according to claim 1, It is characterized in that The synthesis method of the Gemini zwitterionic surfactant is as follows: S1. 1,3-dichloro-2-propanol and alkyl halide are reacted to obtain intermediate 1, the structure of which is as follows: ; Among them, R 3 =C6-C18 alkyl chain; S2. Intermediate 1 is reacted with a disubstituted amine to obtain intermediate 2, the structure of which is as follows: ; Among them, R 1 , R 2 =C1-C14 alkyl chain; S3. The intermediate 2 is reacted with propane sultone to obtain the product.

4. The preparation method according to claim 3, It is characterized in that The alkyl halide in step S1 is selected from at least one of bromhexane, chlorhexane, bromide heptane, chlorhexane, octane bromide, octane chloride, bromononane, chlornonane, decane bromide, decane chloride, dodecane bromide, dodecane chloride, tetradecane bromide, tetradecane chloride, octadecane bromide, and octadecane chloride, the molar ratio of 1,3-dichloro-2-propanol to the alkyl halide is 1:1-1.1, and a base is added, and the base is selected from at least one of NaOH, KOH, triethylamine, diethylamine, sodium carbonate, and potassium carbonate; the disubstituted amine in step S2 is selected from at least one of N-dodecylmethylamine, N-ethyldodecylamine, N-hexylmethylamine, N-tetradecylmethylamine, N,N-ditetradecylamine, N,N-didodecylamine, and dioctylamine, and the molar ratio of the intermediate 1 to the disubstituted amine is 1:2-2.1; the molar ratio of the intermediate 2 to propane sultone in step S3 is 1:2-2.

1.

5. The preparation method according to claim 1, It is characterized in that The synthesis method of the degradable fluorocarbon surfactant is as follows: fluorocarbonic acid and ethylene glycol ether are reacted under the action of a catalyst to obtain a product.

6. The preparation method according to claim 5, It is characterized in that The molar ratio of the fluorocarbonic acid and the glycol ether is 1:1-1.1, the catalyst is concentrated sulfuric acid with a concentration greater than 98%, the reaction temperature is 90-110°C, and the reaction time is 5-7h; the fluorocarbonic acid is selected from at least one of perfluorooctanoic acid, perfluoroheptanoic acid, perfluorohexanoic acid, and perfluoropentanoic acid; the glycol ether is at least one of triethylene glycol ether, tetraethylene glycol ether, tetraethylene glycol ether, and hexaethylene glycol ether.

7. An environmentally friendly and efficient drainage agent prepared by the preparation method according to any one of claims 1 to 6.

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