A foaming agent and its preparation method and application

Abstract

The present invention relates to the technical field of foaming agents, and discloses a foaming agent and its preparation method and application. The present invention reacts polyethylene glycol and 4,4'-N-benzylaniline dicarboxylic acid, and then reacts with 2-bromoethyl sodium sulfonate to obtain a foaming agent. The foaming agent of the present invention uses the polyether segment of polyethylene glycol as the main chain, and a large number of sulfonate groups are introduced into the side chain, showing a strong surface activity performance. At different mass concentrations, it has a very high foam volume and half-life, and the foaming performance is very good. And in oil field well water with different mineralization degrees, the foam volume and half-life are also very high, the salt resistance is excellent, and the high temperature resistance is good.

Description

Technical Field

[0001] The invention relates to the technical field of foaming agents, in particular to a foaming agent and a preparation method and application thereof. Background Art

[0002] Foam flooding technology has the characteristics of good plugging performance and high oil-water selectivity, and is widely used in oil and gas field development. Common foaming agents used in oil and gas field development mainly include sulfonates, polyethers, zwitterions, phosphine methyl phenolic resins, etc. Among them, sulfonate foaming agents have high surface activity, good foaming performance, and are widely used. The patent with announcement number CN115991985B discloses an anionic foaming agent for high-mineralization low-permeability oil reservoirs and its preparation and application. The anionic foaming agent obtained by compounding with fatty alcohol polyoxyethylene ether sodium sulfate, alkyl diphenyl ether disulfonate, sodium polyaspartate, etc. as raw materials has excellent foaming performance, foam stability and thermal stability. However, the anionic foaming agent of the patent does not have good salt resistance, and it is difficult to meet the practical application of the foaming agent in the exploitation of high-salt oil and gas fields. The preparation method of the foaming agent prepared by the present invention has the advantages of good foaming performance, high temperature resistance, and high salt resistance. Summary of the invention

[0003] The technical problem to be solved is: providing a method for preparing a foaming agent, solving the problems of poor foaming performance, high temperature resistance and salt resistance of traditional sulfonate foaming agents.

[0004] Technical solution: A method for preparing a foaming agent, comprising the following steps:

[0005] Step S1, adding polyethylene glycol, 4,4'-N-benzylaniline dicarboxylic acid and p-toluenesulfonic acid into a reaction kettle, carrying out a polymerization reaction, cooling the discharged material, washing with acetone, and drying to obtain a foaming agent precursor.

[0006] Step S2, add water and ethanol in a volume ratio of 1: (1-2) to a reaction container, add a foaming agent precursor, sodium 2-bromoethylsulfonate, and sodium carbonate, react, remove ethanol by vacuum distillation, add a saturated sodium chloride solution, then extract and wash with dichloromethane, dry the extract with anhydrous sodium sulfate, vacuum distill the filtrate, wash with acetone, and dry to obtain a foaming agent. The reaction formula is as follows:

[0007] .

[0008] Wherein, in step S1, the molar ratio of polyethylene glycol, 4,4'-N-benzylaniline dicarboxylic acid, and p-toluenesulfonic acid is (1.2-1.4):1:(0.014-0.02). The molecular weight of polyethylene glycol is 400-600 Da.

[0009] Among them, in S1, during the polymerization reaction, the pressure in the reactor is controlled to be 0.08-0.1 MPa, the temperature during the reaction is 180-200°C, and the reaction time is 5-8h.

[0010] Wherein, in step S2, the mass ratio of the foaming agent precursor, sodium 2-bromoethylsulfonate, and sodium carbonate is 1: (0.08-0.2): (0.07-0.17).

[0011] Wherein, in step S2, the reaction temperature is 80-90°C and the reaction time is 12-24h.

[0012] Among them, the preparation method of 4,4'-N-benzylaniline dicarboxylic acid includes: adding ethanol, p-aminobenzoic acid, and p-formylbenzoic acid to a reaction container, stirring and dissolving, performing a condensation reaction at 35-50°C for 5-7h, then adding sodium borohydride, performing a reduction reaction at 20-30°C for 2-3h, distilling under reduced pressure, adding water, then extracting and washing with dichloromethane, drying the extract with anhydrous sodium sulfate, heating and volatilizing the filtrate until a precipitate is precipitated, then cooling in an ice water bath, and recrystallizing to obtain 4,4'-N-benzylaniline dicarboxylic acid. The reaction formula is:

[0013] .

[0014] Among them, the molar ratio of p-aminobenzoic acid, p-formylbenzoic acid and sodium borohydride is 1: (0.95-1.05): (1.1-1.2).

[0015] The foaming agent of the present invention can be applied to oil and gas field mining additives.

[0016] The technical effect is as follows: the present invention utilizes 4,4'-N-benzylaniline dicarboxylic acid obtained by the reaction of p-aminobenzoic acid and p-formylbenzoic acid to carry out an esterification reaction with polyethylene glycol, polymerizes to obtain a foaming agent precursor, and then reacts with sodium 2-bromoethylsulfonate to obtain a new foaming agent. By adjusting the amount of sodium 2-bromoethylsulfonate, the content of the sodium sulfonate salt group in the side chain of the foaming agent is controlled, thereby controlling the surface active foaming performance of the foaming agent.

[0017] The foaming agent of the present invention uses a polyether segment of polyethylene glycol as the main chain, introduces a large number of sulfonate groups into the side chain, exhibits strong surface activity, has high foam volume and half-life at different mass concentrations, and has good foaming performance. Moreover, in oil field well water with different salinities, the foam volume and half-life are also high, and the salt resistance is excellent.

[0018] The main molecular chain of the foaming agent of the present invention contains more benzene ring groups, has good heat resistance, high structural stability, is not easy to be thermally decomposed at high temperature, and after high-temperature heat treatment, the foaming agent still maintains good structural stability and bubble performance, the foam volume and half-life decrease slightly, has good high temperature resistance, and has good practical application in oil and gas field exploitation. DETAILED DESCRIPTION

[0019] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0020] The CAS number of p-formylbenzoic acid is 619-66-9. The CAS number of sodium 2-bromoethylsulfonate is 4263-52-9.

[0021] Sodium fatty alcohol polyoxyethylene ether sulfonate, model AESO, Wuhan Jiayehe New Material Technology Co., Ltd.

[0022] Example 1

[0023] (1) Add 60 mL of ethanol, 20 mmol of p-aminobenzoic acid, and 20 mmol of p-formylbenzoic acid into a reaction container, stir to dissolve, heat to 40°C, and carry out condensation reaction for 7 hours. Then add 22 mmol of sodium borohydride and carry out reduction reaction at 25°C for 3 hours. Distill under reduced pressure, add water, and then extract and wash with dichloromethane. The extract is dried over anhydrous sodium sulfate. The filtrate is heated and evaporated until a precipitate is precipitated. Then, it is cooled in an ice-water bath and recrystallized to obtain 4,4'-N-benzylaniline dicarboxylic acid.

[0024] (2) Add 65 mmol polyethylene glycol 400, 50 mmol 4,4'-N-benzylaniline dicarboxylic acid, and 0.8 mmol p-toluenesulfonic acid into a reactor. The pressure in the reactor is 0.1 MPa. Heat to 180°C and perform polymerization for 8 hours. Cool the discharged material, wash it with acetone, and dry it to obtain a foaming agent precursor.

[0025] (3) Add 150 mL of water, 150 mL of ethanol, 30 g of a foaming agent precursor, 2.4 g of sodium 2-bromoethylsulfonate, and 2.1 g of sodium carbonate to a reaction container, heat to 85°C, react for 12 h, remove the ethanol by distillation under reduced pressure, add a saturated sodium chloride solution, extract and wash with dichloromethane, dry the extract with anhydrous sodium sulfate, distill the filtrate under reduced pressure, wash with acetone, and dry to obtain a foaming agent.

[0026] Example 2

[0027] (1) Add 70 mL of ethanol, 20 mmol of p-aminobenzoic acid, and 21 mmol of p-formylbenzoic acid to a reaction container, stir to dissolve, heat to 35°C, and carry out condensation reaction for 7 hours. Then add 24 mmol of sodium borohydride and carry out reduction reaction at 20°C for 2 hours. Distill under reduced pressure, add water, and then extract and wash with dichloromethane. The extract is dried over anhydrous sodium sulfate. The filtrate is heated and evaporated until a precipitate is precipitated. Then, it is cooled in an ice-water bath and recrystallized to obtain 4,4'-N-benzylaniline dicarboxylic acid.

[0028] (2) Add 70 mmol polyethylene glycol 600, 50 mmol 4,4'-N-benzylaniline dicarboxylic acid, and 0.7 mmol p-toluenesulfonic acid into a reactor. The pressure in the reactor is 0.1 MPa. Heat to 200°C and perform polymerization for 5 hours. Cool the discharged material, wash it with acetone, and dry it to obtain a foaming agent precursor.

[0029] (3) Add 150 mL of water, 200 mL of ethanol, 30 g of a foaming agent precursor, 3.8 g of sodium 2-bromoethylsulfonate, and 3.2 g of sodium carbonate to a reaction container, heat to 90°C, react for 12 h, remove ethanol by distillation under reduced pressure, add saturated sodium chloride solution, then extract and wash with dichloromethane, dry the extract with anhydrous sodium sulfate, distill the filtrate under reduced pressure, wash with acetone, and dry to obtain a foaming agent.

[0030] Example 3

[0031] (1) Add 60 mL of ethanol, 20 mmol of p-aminobenzoic acid, and 19 mmol of p-formylbenzoic acid into a reaction container, stir to dissolve, heat to 50°C, and carry out condensation reaction for 5 hours. Then add 22 mmol of sodium borohydride and carry out reduction reaction at 30°C for 2 hours. Distill under reduced pressure, add water, and then extract and wash with dichloromethane. The extract is dried over anhydrous sodium sulfate. The filtrate is heated and evaporated until a precipitate is precipitated. Then, it is cooled in an ice-water bath and recrystallized to obtain 4,4'-N-benzylaniline dicarboxylic acid.

[0032] (2) Add 60 mmol polyethylene glycol 400, 50 mmol 4,4'-N-benzylaniline dicarboxylic acid, and 1 mmol p-toluenesulfonic acid into a reactor. The pressure in the reactor is 0.08 MPa. Heat to 200°C and perform polymerization for 5 hours. Cool the discharged material, wash it with acetone, and dry it to obtain a foaming agent precursor.

[0033] (3) Add 150 mL of water, 300 mL of ethanol, 30 g of a foaming agent precursor, 5 g of sodium 2-bromoethylsulfonate, and 4.2 g of sodium carbonate to a reaction vessel, heat to 90°C, react for 18 h, remove the ethanol by distillation under reduced pressure, add a saturated sodium chloride solution, then extract and wash with dichloromethane, dry the extract with anhydrous sodium sulfate, distill the filtrate under reduced pressure, wash with acetone, and dry to obtain a foaming agent.

[0034] Example 4

[0035] (1) Add 60 mmol of polyethylene glycol 600, 50 mmol of 4,4'-N-benzylaniline dicarboxylic acid (prepared in Example 1), and 0.8 mmol of p-toluenesulfonic acid into a reaction kettle. The pressure in the reaction kettle is 0.08 MPa. Heat to 200°C and perform polymerization reaction for 6 hours. Cool the discharged material, wash it with acetone, and dry it to obtain a foaming agent precursor.

[0036] (2) Add 150 mL of water, 300 mL of ethanol, 30 g of a foaming agent precursor, 6 g of sodium 2-bromoethylsulfonate, and 5.1 g of sodium carbonate to a reaction container, heat to 80°C, react for 24 h, remove the ethanol by distillation under reduced pressure, add a saturated sodium chloride solution, then extract and wash with dichloromethane, dry the extract with anhydrous sodium sulfate, distill the filtrate under reduced pressure, wash with acetone, and dry to obtain a foaming agent.

[0037] In Comparative Example 1, the foaming agent precursor (prepared in Example 1) was used as the foaming agent.

[0038] In Comparative Example 2, sodium fatty alcohol polyoxyethylene ether sulfonate was used as a foaming agent.

[0039] The foaming agent was added into deionized water to prepare foaming solutions with different mass concentrations, and the foaming performance of the foaming agent was tested according to the method of GB / T 7462-1994.

[0040] Table 1 Foam volume test

[0041]

[0042] Table 2 Half-life test

[0043]

[0044] The foaming solution with a mass concentration of 2 g / L was heated to 100°C, condensed and refluxed for 72 hours, cooled to room temperature, and then the foam volume and half-life were tested.

[0045] Table 3 Heat resistance test

[0046]

[0047] The foaming agent was added into oilfield well water with different salinities (the salinities were 10448.2 mg / L and 28457.9 mg / L, respectively) to prepare a foaming solution with a mass concentration of 2 g / L, and the foam volume and half-life of the foaming agent were tested.

[0048] Table 4 Salt resistance performance test

[0049]

[0050] After testing, comparative example 1 uses a foaming agent precursor as a foaming agent, which does not contain a sulfonate group and has poor surface activity. When foaming liquids of different mass concentrations are prepared, the foam volume and half-life are very low, and the foaming performance is very poor.

[0051] The foaming agent prepared in Example 1-4 has a polyether segment of polyethylene glycol as the main chain, and a large number of sulfonate groups are introduced into the side chain, which has a strong surface activity. At different mass concentrations, it has a very high foam volume and half-life, and the foaming performance is very good. At the same time, the main chain of the molecule contains more benzene ring groups, has good heat resistance, high structural stability, and is not easy to be thermally decomposed at high temperature. After high-temperature heat treatment, the foaming agent still maintains a good structural stability, and the foam volume and half-life decrease very little, and the foaming performance is excellent. In addition, in oil field well water with different mineralization degrees, the foam volume and half-life are also very high, and the salt resistance is excellent.

[0052] Comparative Example 2 uses conventional sodium fatty alcohol polyoxyethylene ether sulfonate as a foaming agent, which also has good surface activity, high foam volume and half-life, and excellent foaming performance. However, sodium fatty alcohol polyoxyethylene ether sulfonate has poor heat resistance, and its structural stability deteriorates after high-temperature heat treatment, resulting in a large decrease in foam volume and half-life. In addition, in oil field well water with different mineralization degrees, the foam volume and half-life are significantly reduced, and the salt resistance is poor.

Claims

1. A method for preparing a foaming agent, characterized in that: The preparation method of the foaming agent comprises the following steps: Step S1, adding polyethylene glycol, 4,4'-N-benzylaniline dicarboxylic acid, and p-toluenesulfonic acid in a molar ratio of (1.2-1.4):1:(0.014-0.02) into a reaction kettle, performing a polymerization reaction, cooling the discharged material, washing with acetone, and drying to obtain a foaming agent precursor; Step S2, adding water, ethanol solvent, a foaming agent precursor in a mass ratio of 1: (0.08-0.2): (0.07-0.17), sodium 2-bromoethylsulfonate, and sodium carbonate into a reaction container, reacting, removing ethanol by distillation under reduced pressure, adding a saturated sodium chloride solution, then extracting and washing with dichloromethane, drying the extract with anhydrous sodium sulfate, distilling the filtrate under reduced pressure, washing with acetone, and drying to obtain a foaming agent.

2. The method for preparing a foaming agent according to claim 1, characterized in that: The molecular weight of the polyethylene glycol in step S1 is 400-600 Da.

3. The method for preparing a foaming agent according to claim 1, characterized in that: In the step S1, during the polymerization reaction, the pressure in the reactor is controlled to be 0.08-0.1 MPa, the temperature during the reaction is 180-200° C., and the reaction time is 5-8 hours.

4. The method for preparing a foaming agent according to claim 1, characterized in that: In step S2, the volume ratio of water to ethanol solvent is 1:(1-2).

5. The method for preparing a foaming agent according to claim 1, characterized in that: In step S2, the reaction temperature is 80-90° C. and the reaction time is 12-24 hours.

6. The method for preparing a foaming agent according to claim 1, characterized in that: The preparation method of 4,4'-N-benzylaniline dicarboxylic acid comprises: adding ethanol, p-aminobenzoic acid and p-formylbenzoic acid into a reaction container, stirring and dissolving them, performing a condensation reaction, then adding sodium borohydride, performing a reduction reaction, performing reduced pressure distillation, adding water, then extracting and washing with dichloromethane, drying the extract with anhydrous sodium sulfate, heating and volatilizing the filtrate until a precipitate is precipitated, then cooling in an ice water bath, and recrystallizing to obtain 4,4'-N-benzylaniline dicarboxylic acid.

7. The method for preparing a foaming agent according to claim 6, characterized in that: The molar ratio of p-aminobenzoic acid, p-formylbenzoic acid and sodium borohydride is 1: (0.95-1.05): (1.1-1.2); The temperature during the condensation reaction is 35-50°C and the time is 5-7h; the temperature during the reduction reaction is 20-30°C and the time is 2-3h.

8. A foaming agent prepared according to the method for preparing a foaming agent according to any one of claims 1 to 7.

9. Use of the foaming agent according to claim 8 in oil and gas field production additives.

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