A non-ionic gemini surfactant for displacement and a preparation method thereof, and a nanoemulsion displacement agent and a preparation method thereof

Abstract

The application discloses a non-ionic gemini surfactant for displacement and a preparation method thereof, and a nano-emulsion displacement agent and a preparation method thereof. The nano-emulsion displacement agent comprises the following raw materials in parts by weight: 20-35 parts of a surfactant; 1-10 parts of a nanometer material; 5-10 parts of a dispersing agent; 15-20 parts of a stabilizer; 15-45 parts of an auxiliary agent; and 30-55 parts of an aqueous phase. The surfactant is a complex system of an anionic surfactant and a non-ionic gemini surfactant. The nano-emulsion displacement agent prepared by the application has good temperature resistance and salt resistance, small particle size, can significantly reduce the oil-water interfacial tension, can easily penetrate into the micro-pore throat of a stratum, can displace crude oil from the pore throat, can improve the oil displacement efficiency, and can further improve the crude oil recovery rate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil and gas field development and enhanced oil recovery, and particularly relates to a non-ionic gemini surfactant for displacement and a preparation method thereof, and a nano-emulsion displacement agent and a preparation method thereof. BACKGROUND

[0002] With the rapid development of oil and gas exploration and development technology, unconventional oil and gas shows great potential under existing economic and technical conditions. However, there are still many problems in theory and technology that need to be solved in the scientific and efficient development of unconventional oil and gas reservoirs.

[0003] The nano displacement agent has high surface activity, can reduce the surface interfacial tension between the formation rock and the external fluid, reduce the capillary force, facilitate and accelerate the flowability of the liquid in the porous medium, natural or artificial fracture network, avoid the occurrence of "liquid phase trapping", and reduce the damage to the oil and gas layer; due to the small size (10-100 mm) of the nano displacement agent, the nano displacement agent can easily enter the formation micro-pore throat, improve the contact efficiency of the stimulation liquid and the formation, reduce the water lock effect of the reservoir, and improve the fracturing stimulation effect of the oil and gas well.

[0004] The patent document with the publication number CN105860949A discloses an imbibition agent composition for oil reservoirs and a preparation of the imbibition agent composition for oil reservoirs, which mainly consists of non-ionic surfactants and anionic surfactants. Although the composition has good imbibition effects in dynamic and static aspects, the interfacial tension does not reach ultra-low, and the residual oil adsorbed in the pores cannot be well stripped, and the oil well recovery rate needs to be further improved.

[0005] Therefore, the present application provides a non-ionic gemini surfactant for displacement and a preparation method thereof, and a nano-emulsion displacement agent and a preparation method thereof. The nano-emulsion displacement agent can efficiently imbibed into the formation micro-pore throat, significantly reduce the oil-water interfacial tension, strip the residual oil adsorbed in the pores, and thus greatly improve the oil well recovery rate. SUMMARY

[0006] In order to solve the above technical problems, the present application provides a non-ionic gemini surfactant for displacement and a preparation method thereof, and a nano-emulsion displacement agent and a preparation method thereof. The nano-emulsion displacement agent can efficiently imbibed into the formation micro-pore throat, significantly reduce the oil-water interfacial tension, strip the residual oil adsorbed in the pores, and thus greatly improve the oil well recovery rate.

[0007] Therefore, in the first aspect of the present application, a non-ionic gemini surfactant for displacement is provided, and the structure formula of the non-ionic gemini surfactant is as follows:

[0008]

[0009] Wherein, n = 12, 14 or 16; x = 8, 12 or 16; y = 5, 9 or 15.

[0010] The present application also provides a method for preparing the above non-ionic gemini surfactant, comprising the following steps:

[0011] S1, p-xylylenediamine and alkyl bromide (molar ratio of 1:2) are dissolved in water and added to a three-necked flask, sodium hydroxide (molar ratio of sodium hydroxide to alkyl bromide is 1:1) is weighed and added to the three-necked flask, magnetic stirring and heating to 80-100°C reflux, constant temperature water bath for 8-12h, then add anhydrous ethanol to obtain intermediate one;

[0012] Wherein, the molar ratio of p-xylylenediamine to alkyl bromide is 1:2, and the molar ratio of sodium hydroxide to alkyl bromide is 1:1;

[0013] S2, the fatty alcohol polyoxyethylene ether is loaded into a three-necked flask, heated with water bath and stirred to reflux; then thionyl chloride is slowly added to the three-necked flask, after titration is completed, reaction at 70-80°C for 8-10 hours, then cooled to room temperature, neutralized with 15% sodium hydroxide solution, then added to a separation funnel to separate the salt, the upper organic layer is retained and washed repeatedly with 85-95°C hot water at 90°C for 5-6 times to obtain intermediate two;

[0014] Wherein, the molar ratio of thionyl chloride to fatty alcohol polyoxyethylene ether is 1.4-1.8:1;

[0015] S3, intermediate one and deionized water are added to a three-necked flask;

[0016] Intermediate two is dissolved in ethanol, then transferred to a constant pressure dropping funnel, and the solution in the constant pressure dropping funnel is slowly added to the three-necked flask, after the molar ratio of intermediate one to intermediate two is 1:2-2.2, sodium hydroxide is added to adjust the pH to 9-11, then refluxed and stirred at 70-80°C for 10-12 hours, then the solvent is removed by rotary evaporation, anhydrous ethanol is added for recrystallization, a large amount of white solid is precipitated, filtered, the filtrate is distilled under reduced pressure to remove the solvent, and finally vacuum dried to obtain the non-ionic gemini surfactant.

[0017] In a preferred embodiment of the present application, the non-ionic gemini surfactant preparation method is as follows:

[0018] S1, p-xylylenediamine and alkyl bromide (molar ratio of 1:2) are dissolved in water and added to a three-necked flask, sodium hydroxide (molar ratio of sodium hydroxide to alkyl bromide is 1:1) is weighed and added to the three-necked flask, magnetic stirring and heating to 80-100°C reflux, constant temperature water bath for 8-12h, then add anhydrous ethanol to obtain intermediate one;

[0019] S2, the fatty alcohol polyoxyethylene ether is loaded into a three-necked flask, heated in a water bath, and stirred to reflux; the thionyl chloride is poured into a 100 mL constant pressure dropping funnel (the molar ratio of thionyl chloride to fatty alcohol polyoxyethylene ether is 1.4-1.8:1); the thionyl chloride is slowly added to the three-necked flask; after the titration is completed, the reaction is carried out at 70-80°C for 8-10 hours, the reaction is stopped, and the mixture is cooled to room temperature; then it is neutralized with a 15% sodium hydroxide solution, and the salt is separated into a separation funnel, the upper organic layer is retained, and it is repeatedly washed with 85-95°C hot water at 90°C for 5-6 times to obtain intermediate two;

[0020] S3, deionized water and intermediate one are added to a three-necked flask, intermediate two is dissolved in ethanol, and then the solution is slowly added to the three-necked flask; after the molar ratio of intermediate one to intermediate two is 1:2-2.2, sodium hydroxide is added to adjust the pH to 9-11, and then refluxing and stirring at 70-80°C for 10-12 hours; when the reaction is stopped, the mixture is separated by rotary evaporation to remove the solvent after cooling to room temperature; after rotary evaporation, anhydrous ethanol is added for recrystallization, a large amount of white solid is precipitated, and then filtered, the filtrate is distilled under reduced pressure to remove the solvent; finally, vacuum drying is performed to obtain the desired product.

[0021] In another aspect, the present application provides a nanoemulsion displacement agent, which comprises the following raw materials by weight:

[0022] 20-35 parts of a surfactant; 1-10 parts of a nanomaterial; 5-10 parts of a wet dispersant; 15-20 parts of a stabilizer; 15-45 parts of an auxiliary agent; and 30-55 parts of an aqueous phase.

[0023] In a preferred embodiment of the present application, the surfactant is a combination of an anionic surfactant and the nonionic gemini surfactant of any one of claims 1 or 2.

[0024] The anionic surfactant is one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and sodium lignosulfonate.

[0025] In a preferred embodiment of the present application, the nanomaterial is one or two of nanosilica, multi-walled carbon nanotubes, zinc oxide, titanium dioxide, magnesium oxide, and nanomolybdenum disulfide.

[0026] In a preferred embodiment of the present application, the wet dispersant is one or more of a carboxylate gemini surfactant, a rosin-based gemini surfactant, and a fatty alcohol polyoxyalkyl ether.

[0027] In a preferred embodiment of the present application, the stabilizer is one or more of ethanol, isopropyl alcohol, sodium p-toluenesulfonate, xanthan gum, and triolein.

[0028] In a preferred embodiment of this solution, the auxiliary agent is one or more of n-heptane, limonene, cyclopentadiene, jasmone, and palm kernel oil.

[0029] The present invention also provides a method for preparing the above-mentioned nanoemulsion displacement agent, comprising the following steps: adding nanomaterials, wetting and dispersing agents, stabilizers and additives to a surfactant, mixing them evenly, adding an aqueous phase at a temperature of 60-80°C, and stirring for 2-3 hours at a speed of 600-1000 r / min to obtain the nanoemulsion displacement agent.

[0030] The beneficial effects of this invention are:

[0031] (1) Using the nano-emulsion displacement agent prepared in this invention for mining can significantly reduce the interfacial tension and surface tension of oil and water, improve emulsification performance, strip oil and gas adsorbed on the rock surface, reduce the water-locking effect of the reservoir, and improve the fracturing and production enhancement effect of oil and gas wells.

[0032] (2) The nanoemulsion displacement agent of the present invention has good temperature and salt resistance, and the nano-permeation displacement agent has a small particle size between 10 and 100 mm, a large specific surface area, and high surface activity. At the same time, it uses a combination of nonionic gemini surfactant and anionic surfactant, resulting in low interfacial tension. The displacement agent can easily permeate into the formation micropore throat, displace oil and gas from the pore throat, and promote and accelerate its flow in porous media, natural or artificial fracture networks.

[0033] (3) The raw materials of the nanoemulsion displacement agent of the present invention are readily available, widely sourced, low in cost, simple in preparation process, and environmentally friendly. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] This embodiment provides a nonionic gemini surfactant, the preparation method of which is as follows:

[0037] (1) Dissolve 13.62g of p-phenylenediamine and 49.85g of alkyl bromide (n=12) in water and add them to a three-necked flask. Weigh 8g of sodium hydroxide and add it to the three-necked flask. Stir magnetically and heat to 90℃ and reflux. Keep warm in a constant temperature water bath for 10h until the reaction is complete. Add anhydrous ethanol to obtain intermediate one.

[0038] (2) 52.67 g of fatty alcohol polyoxyethylene ether (x = 8, y = 9) was charged into a three-necked flask, heated in a water bath, and stirred to reflux. 21.41 g of thionyl chloride was poured into a constant pressure dropping funnel and slowly added dropwise into the three-necked flask. After the titration was completed, the reaction was carried out at 70°C for 10 hours, the reaction was stopped, and cooled to room temperature. Neutralized with 15% sodium hydroxide solution, then transferred to a separating funnel to separate the salt, the upper organic layer was retained, and washed repeatedly with hot water at 90°C for 6 times to obtain intermediate 2.

[0039] (3) Deionized water and 23.64 g of intermediate 1 were added to a three-necked flask, 59.97 g of intermediate 2 was dissolved in ethanol, then transferred to a constant pressure dropping funnel, and the solution was slowly added dropwise into the three-necked flask. Sodium hydroxide was added to adjust the pH to about 10, then refluxed and stirred at 80°C for 10 hours. When the reaction was stopped, the mixture was separated by rotary evaporation to remove the solvent after cooling to room temperature. After rotary evaporation, recrystallization was carried out by adding anhydrous ethanol, a large amount of white solid was precipitated, and then filtered. The filtrate was distilled under reduced pressure to remove the solvent. Finally, vacuum drying was carried out to obtain the desired product, the structure of which is shown in the following formula:

[0040]

[0041] Example 2

[0042] The preparation of the nanoemulsion displacement agent of the present example is based on the nanoemulsion displacement agent which comprises the following raw materials in parts by weight:

[0043] 20 parts of surfactant;

[0044] 3 parts of nanomaterial;

[0045] 5 parts of wet dispersant;

[0046] 15 parts of stabilizer;

[0047] 25 parts of auxiliary agent;

[0048] 32 parts of aqueous phase.

[0049] Among them, the surfactant is 15 parts of sodium dodecyl sulfate and 5 parts of non-ionic gemini surfactant prepared in example 1.

[0050] The nanomaterial is nanosilica.

[0051] The wet dispersant is carboxylate gemini surfactant.

[0052] The stabilizer is 12 parts of isopropanol and 3 parts of sodium p-toluenesulfonate.

[0053] The auxiliary agent is limonene.

[0054] The water phase is deionized water.

[0055] The preparation method of the nanoemulsion displacement agent comprises the following steps: adding a nanomaterial, a wet dispersant, a stabilizer, and an auxiliary agent into a surfactant respectively, uniformly mixing, adding a water phase at a temperature of 60 DEG C, stirring at a rotating speed of 600 r / min for 2 h, and obtaining the nanoemulsion displacement agent.

[0056] Example 3

[0057] The preparation of the nanoemulsion displacement agent of the present example is based on the nanoemulsion displacement agent which comprises the following raw materials by weight:

[0058] 28 parts of a surfactant;

[0059] 5 parts of a nanomaterial;

[0060] 5 parts of a wet dispersant;

[0061] 15 parts of a stabilizer;

[0062] 21 parts of an auxiliary agent;

[0063] 26 parts of a water phase.

[0064] The surfactant is 18 parts of sodium dodecyl sulfate and 10 parts of the nonionic gemini surfactant prepared in Example 1.

[0065] The nanomaterial is a multi-walled carbon nanotube.

[0066] The wet dispersant is a fatty alcohol polyoxyalkyl ether.

[0067] The stabilizer is isopropyl alcohol.

[0068] The auxiliary agent is n-heptane.

[0069] The water phase is deionized water.

[0070] The preparation method of the nanoemulsion displacement agent comprises the following steps: adding a nanomaterial, a wet dispersant, a stabilizer, and an auxiliary agent into a surfactant respectively, uniformly mixing, adding a water phase at a temperature of 60 DEG C, stirring at a rotating speed of 600 r / min for 2 h, and obtaining the nanoemulsion displacement agent.

[0071] Example 4

[0072] The preparation of the nanoemulsion displacement agent of the present example is based on the nanoemulsion displacement agent which comprises the following raw materials by weight:

[0073] 25 parts of a surfactant;

[0074] 8 parts of a nanomaterial;

[0075] 6 parts of wetting dispersant;

[0076] 15 parts of stabilizer;

[0077] 18 parts of auxiliary agent;

[0078] 28 parts of water phase.

[0079] The surfactant is 15 parts of sodium dodecyl benzene sulfonate and 10 parts of non-ionic gemini surfactant prepared in Example 1.

[0080] The nanomaterial is titanium dioxide.

[0081] The wetting dispersant is rosin-based gemini surfactant.

[0082] The stabilizer is xanthan gum.

[0083] The auxiliary agent is palm kernel oil.

[0084] The water phase is deionized water.

[0085] The preparation method of the above-mentioned nanoemulsion displacement agent comprises the following steps: adding nanomaterial, wetting dispersant, stabilizer, auxiliary agent into surfactant respectively, mixing uniformly, adding water phase at a temperature of 80℃, stirring at a speed of 1000r / min for 2.5h to obtain a nanoemulsion displacement agent.

[0086] Comparative Example 1

[0087] The nanoemulsion displacement agent is prepared according to the same method and raw material formula as in Example 3, with the only difference being that there is no surfactant in the formula.

[0088] The formula of this comparative example is 5 parts of nanomaterial, 5 parts of wetting dispersant, 15 parts of stabilizer, 21 parts of auxiliary agent, and 26 parts of water phase.

[0089] Comparative Example 2

[0090] The nanoemulsion displacement agent is prepared according to the same method and raw material formula as in Example 3, with the only difference being that there is no wetting dispersant in the formula.

[0091] The formula of this comparative example is 28 parts of surfactant (18 parts of sodium dodecyl sulfate and 10 parts of non-ionic gemini surfactant prepared in Example 1), 5 parts of nanomaterial, 15 parts of stabilizer, 21 parts of auxiliary agent, and 26 parts of water phase.

[0092] Comparative Example 3

[0093] The nanoemulsion displacement agent is prepared according to the same method and raw material formula as in Example 3, with the only difference being that there is no stabilizer and auxiliary agent in the formula.

[0094] The formulation of the present comparative example is 28 parts of surfactant (18 parts of sodium dodecyl sulfate and 10 parts of nonionic gemini surfactant prepared in Example 1), 5 parts of nanomaterial, 5 parts of wet dispersant, 26 parts of water phase.

[0095] Comparative Example 4

[0096] The nanoemulsion displacement agent was prepared according to the same method and raw material formulation as in Example 3, except that the nonionic gemini surfactant was not contained in the surfactant combination in the formulation.

[0097] The formulation of the present comparative example is 28 parts of anionic surfactant, 5 parts of nanomaterial, 5 parts of wet dispersant, 15 parts of stabilizer, 21 parts of auxiliary agent, 26 parts of water phase.

[0098] Comparative Example 5

[0099] The nanoemulsion displacement agent was prepared according to the same method and raw material formulation as in Example 3, except that the anionic surfactant was not contained in the surfactant combination in the formulation.

[0100] The formulation of the present comparative example is 28 parts of nonionic gemini surfactant prepared in Example 1, 5 parts of nanomaterial, 5 parts of wet dispersant, 15 parts of stabilizer, 21 parts of auxiliary agent, 26 parts of water phase.

[0101] Experimental Example 1

[0102] A number of dried cores, a surface tension meter and a spinning drop interfacial tension meter were taken, and the nanoemulsion displacement agents prepared in Examples 2 to 4 and Comparative Examples 1 to 5 were subjected to performance test experiments, and the specific results are shown in Table 1.

[0103] Table 1 Performance of each nanoemulsion displacement agent

[0104]

[0105] As can be seen from the experimental results in Table 1, the surfactant, wet dispersant, stabilizer and auxiliary agent can significantly reduce the interfacial tension and surface tension, and as can be seen from Comparative Examples 1 to 3, the addition of the surfactant, wet dispersant, stabilizer and auxiliary agent in the nanoemulsion displacement agent helps to improve the product performance, and as can be seen from the comparison of Comparative Example 4, Comparative Example 5 and Example 3, the anionic surfactant and the nonionic gemini surfactant have a synergistic effect after compounding, which helps to improve the product performance.

[0106] The foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and operation described. Accordingly, all such variations are intended to be included within the scope of the present application as defined in the claims below and their equivalents.

Claims

1. A non-ionic gemini surfactant for displacement, characterized in that: the non-ionic gemini surfactant has the following structure: wherein n = 12, 14 or 16; x = 8, 12 or 16; y = 5, 9 or 15. comprising the following steps:

2. A process for the preparation of the nonionic gemini surfactant of claim 1, characterized in that, S1, dissolving p-xylylenediamine and alkyl bromide in water, then adding sodium hydroxide, magnetic stirring and heating to 80-100℃ reflux, constant temperature water bath for 8-12 h, then adding anhydrous ethanol to obtain intermediate one; wherein the molar ratio of p-xylylenediamine to alkyl bromide is 1:2, and the molar ratio of sodium hydroxide to alkyl bromide is 1:1; S2, loading fatty alcohol polyoxyethylene ether into a three-necked flask, heating in water bath while stirring and refluxing; then slowly adding thionyl chloride into the three-necked flask, after titration, reacting at 70-80℃ for 8-10 hours, then cooling to room temperature, neutralizing with 15% sodium hydroxide solution, then adding into a separating funnel to separate the salt, retaining the upper organic layer, and repeatedly washing with 85-95℃ hot water at 90℃ for 5-6 times to obtain intermediate two; wherein the molar ratio of thionyl chloride to fatty alcohol polyoxyethylene ether is 1.4-1.8:1; S3, adding intermediate one and deionized water into a three-necked flask; dissolving intermediate two in ethanol, then transferring into a constant pressure dropping funnel, slowly adding the solution in the constant pressure dropping funnel into the three-necked flask, adding sodium hydroxide to adjust the pH to 9-11 after the molar ratio of intermediate one to intermediate two is 1:2-2.2, then refluxing and stirring at 70-80℃ for 10-12 hours, then removing the solvent by rotary evaporation, adding anhydrous ethanol for recrystallization, precipitating a large amount of white solid, filtering, removing the solvent from the filtrate by distillation under reduced pressure, and finally drying under vacuum to obtain the non-ionic gemini surfactant. The nanoemulsion displacement agent comprises the following raw materials by weight:

3. A nanoemulsion displacement agent characterized in that, 20-35 parts of a surfactant, which is the non-ionic gemini surfactant according to any one of claims 1 or 2; 1-10 parts of a nanomaterial; 5-10 parts of a wet dispersing agent; 15-20 parts of a stabilizer; 15-45 parts of an auxiliary agent; 30-55 parts of an aqueous phase. The surfactant is a combination of an anionic surfactant and the non-ionic gemini surfactant according to any one of claims 1 or 2; 4. The nanoemulsion displacer of claim 3, wherein, The anionic surfactant is one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and sodium lignosulfonate. The nanomaterial is one or two of nanosilica, multi-walled carbon nanotube, zinc oxide, titanium dioxide, magnesium oxide, and nanomolybdenum disulfide.

5. The nanoemulsion displacer of claim 4, wherein, The wet dispersing agent is one or more of carboxylate gemini surfactant, rosin-based gemini surfactant, and fatty alcohol polyoxyalkyl ether.

6. The nanoemulsion displacement agent of claim 4, wherein, The stabilizer is one or more of ethanol, isopropyl alcohol, sodium p-toluenesulfonate, xanthan gum, and triolein.

7. The nanoemulsion displacement agent of claim 4, wherein, The auxiliary agent is one or more of n-heptane, limonene, cyclopentadiene, jasmonate, and palm kernel oil.

8. The nanoemulsion displacement agent of claim 4, wherein, ​ 9. A process for the preparation of a nanoemulsion repelling agent according to any one of claims 3 to 7, characterized in that, The method comprises the following steps: adding nanometer material, wetting dispersant, stabilizer and auxiliary agent into surfactant respectively, mixing uniformly, adding water phase under the condition of temperature of 60-80 DEG C and rotating speed of 600-1000 r / min, stirring for 2-3 h, and obtaining nanoemulsion expelling agent.

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