A compound, a method for preparing the same, and use thereof as a smart foaming agent

Abstract

The present invention relates to a compound, its method of preparation and use as a smart foaming agent. The compound has the structural formula as shown in formula II),

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction, and in particular to a smart foam. Background Technology

[0002] Foam, as a multiphase colloidal dispersion system, possesses a large surface area and complex fluid properties. Due to its small particle size, large specific surface area, and good flowability, foam has wide applications in various fields, particularly in oil and gas extraction, such as foam drainage gas production, foam drilling fluid, foam fracturing fluid, and foam profile control. In natural gas extraction, foam can effectively reduce fluid density, promote the drainage of fluid accumulated at the bottom of the well, alleviate the blockage problem caused by fluid accumulation, and thus increase gas production. In tertiary oil recovery, foam can also serve as an effective profile control method, reducing surface tension and controlling system flowability, effectively improving the sweep efficiency of the system in heterogeneous reservoirs. Foam fracturing fluid, based on conventional fracturing fluids, possesses characteristics such as low filtration loss, high flowback rate, and minimal formation damage, making it particularly suitable for fracturing and stimulation of unconventional reservoirs such as water-sensitive, low-permeability, low-pressure, shale, and tight oil and gas formations.

[0003] In practical applications, it is always desirable for foam to exhibit good foaming and foam-stabilizing properties under specific application environments. After fulfilling its performance requirements, it is also desirable for the foam to defoam quickly to avoid causing new problems for produced fluid post-processing and the environment. However, existing foamed fluids used in conventional oil and gas development cannot automatically defoam, thus increasing the post-processing procedures and costs of produced fluids. Summary of the Invention

[0004] One aspect of the present invention provides an intermediate compound having the structural formula shown in Formula I).

[0005]

[0006] The second aspect of this invention provides a compound with the structural formula shown in Formula II).

[0007]

[0008] The third invention provides a method for preparing the intermediate compound as described in the first invention, comprising the following steps:

[0009] 1) Stearic acid polyoxyethylene ether, N,N-dimethylglycine, 4-dimethylaminopyridine and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were added to the first solvent and the reaction was sealed to obtain a first reaction solution containing the intermediate compound;

[0010] 2) The intermediate compound is purified from the first reaction solution to obtain the intermediate compound.

[0011] In one specific embodiment, the molar ratio of the stearic acid polyoxyethylene ether, the N,N-dimethylglycine, the 4-dimethylaminopyridine, and the 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is (3-7):(2.5-6.5);(0.25-1):(3-5).

[0012] In one specific embodiment, the molar ratio of the stearic acid polyoxyethylene ether, the N,N-dimethylglycine, the 4-dimethylaminopyridine and the 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is (7-12):(6.5-10):1:(5-12).

[0013] In one specific embodiment, the sealing reaction takes 24 to 72 hours.

[0014] In one specific embodiment, the first reaction solution is extracted with saturated brine to produce an aqueous phase and an organic phase; the separated aqueous phase is added to the first solvent and extracted again with saturated brine. After repeating this process multiple times, the organic phases produced from each extraction are combined, and then the first solvent is removed to obtain the intermediate compound.

[0015] In one specific embodiment, the first solvent is dichloromethane.

[0016] The fourth invention provides a method for preparing the compound as described in the second invention, comprising the following steps:

[0017] I) Dissolve the intermediate compound prepared by the method described in any one of the present invention or any one of the methods described in the third invention with sodium chloroacetate in a second solvent, and after reaction, obtain a second reaction solution containing the compound;

[0018] II) The compound is purified from the second reaction solution to obtain the compound.

[0019] In one specific embodiment, the molar ratio of the intermediate compound to the sodium chloroacetate is (3 to 7):(3 to 10).

[0020] In one specific embodiment, the molar ratio of the intermediate compound to the sodium chloroacetate is 1:(1 to 1.4).

[0021] In one specific embodiment, in step I), the temperature of the reaction is 80 to 100°C, and the reaction time is 12 to 36 hours.

[0022] In one specific embodiment, the second solvent is a mixture of ethanol and water, preferably, the volume ratio of ethanol to water is (5-8):1.

[0023] In one specific embodiment, in step II), the second solvent in the second reaction solution is removed by rotary evaporation, then the sodium chloroacetate is removed by washing with ethanol and filtration, and the compound is obtained after rotary evaporation to remove ethanol again.

[0024] The fifth invention provides the use of compounds prepared by the method according to the second invention or any one of the fourth invention as foaming agents.

[0025] The beneficial effects of this invention are:

[0026] This invention provides a temperature-responsive, switchable surfactant for oil and gas development and its preparation method. This temperature-responsive, switchable surfactant can be used as a foaming agent, adjusting foam stability within a temperature range of 20°C to 120°C using temperature differences. The foam exhibits superior stability at high temperatures and rapid foam collapse at low temperatures. These characteristics enable it to demonstrate excellent foaming and foam-stabilizing properties in oil and gas development applications, while quickly defoaming after fulfilling its performance, simplifying post-processing of produced fluids and reducing costs. This provides a theoretical foundation and technological reserves for oil and gas extraction. Detailed Implementation

[0027] The present invention will be further described in detail below through preferred embodiments, but these embodiments do not constitute a limitation thereof.

[0028] Unless otherwise specified, all reagents used in the embodiments of this invention are commercially available.

[0029] Example 1

[0030] (1) Preparation of tertiary amine intermediates

[0031] Weigh out 3 mmol of dried polyoxyethylene stearate, 2.5 mmol of N,N-dimethylglycine, 0.25 mmol of 4-dimethylaminopyridine (DMAP), and 3 mmol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), and add them to a reaction vessel containing 100 mL of dichloromethane. Seal the vessel and stir at room temperature for 24 h. After the reaction is complete, extract the organic phase with saturated brine to separate it. Add dichloromethane to the aqueous phase again and extract with saturated brine again, repeating this process several times. Combine the organic phases, evaporate the solvent, and cool to obtain a pale yellow solid, which is the intermediate.

[0032] (2) Preparation of target temperature-responsive switching surfactants

[0033] 3 mmol of the intermediate and 3 mmol of sodium chloroacetate were dissolved in 100 mL of a mixture of ethanol and water (v / v = 5:1), and the mixture was placed in a flask and heated to 80 °C for reaction. The reaction was carried out under reflux with circulating water for 12 h. After the reaction was completed, the solvent was removed by rotary evaporation, and the mixture was washed with ethanol and filtered to remove sodium chloroacetate. The ethanol was then removed by rotary evaporation again. After cooling, a white or pale yellow solid was obtained, which was the target product.

[0034] Example 2

[0035] (1) Preparation of tertiary amine intermediates

[0036] Weigh out 4 mmol of dried polyoxyethylene stearate, 3 mmol of N,N-dimethylglycine, 0.4 mmol of DMAP, and 3.5 mmol of EDCI, and add them to a reaction vessel containing 125 mL of dichloromethane. Seal the vessel and stir at room temperature for 36 h. After the reaction is complete, extract the organic phase with saturated brine to separate it. Add dichloromethane to the aqueous phase again and extract with saturated brine again, repeating this process several times. Combine the organic phases, evaporate the solvent, and cool to obtain a pale yellow solid, which is the intermediate.

[0037] (2) Preparation of target temperature-responsive switching surfactants

[0038] 4 mmol of the intermediate and 5 mmol of sodium chloroacetate were dissolved in 125 mL of a mixture of ethanol and water (v / v = 6:1), and the mixture was placed in a flask and heated to 85 °C for reaction. The reaction was carried out under reflux with circulating water for 16 h. After the reaction was completed, the solvent was removed by rotary evaporation, and the mixture was washed with ethanol and filtered to remove sodium chloroacetate. The ethanol was then removed by rotary evaporation again. After cooling, a white or pale yellow solid was obtained, which was the target product.

[0039] Example 3

[0040] (1) Preparation of tertiary amine intermediates

[0041] Weigh out 5 mmol of dried stearic acid polyoxyethylene ether, 4 mmol of N,N-dimethylglycine, 0.6 mmol of DMAP, and 4 mmol of EDCI, and add them to a reaction vessel containing 150 mL of dichloromethane. Stir at room temperature for 48 h. Keep the system sealed during the reaction to prevent solvent evaporation and water ingress. After the reaction is complete, extract the organic phase with saturated brine. Add dichloromethane to the aqueous phase again and extract with saturated brine again, repeating this process several times. Combine the organic phases, evaporate the solvent, and cool to obtain a pale yellow solid, which is the intermediate.

[0042] (2) Preparation of target temperature-responsive switching surfactants

[0043] 5 mmol of the intermediate and 6.5 mmol of sodium chloroacetate were dissolved in 150 mL of a mixture of ethanol and water (v / v = 6.5:1), and the mixture was placed in a flask and heated to 90 °C for reaction. The mixture was refluxed with circulating water and the reaction proceeded for 24 h. After the reaction was complete, the solvent was removed by rotary evaporation. The mixture was then washed with ethanol and filtered to remove the sodium chloroacetate. The ethanol was removed again by rotary evaporation. After cooling, a white or pale yellow solid was obtained, which was the target product.

[0044] Example 4

[0045] (1) Preparation of tertiary amine intermediates

[0046] Weigh out 6 mmol of dried stearic acid polyoxyethylene ether, 5.5 mmol of N,N-dimethylglycine, 0.8 mmol of DMAP, and 4.5 mmol of EDCI, and add them to a reaction vessel containing 175 mL of dichloromethane. Stir at room temperature for 60 h. Keep the system sealed during the reaction to prevent solvent evaporation and water ingress. After the reaction is complete, extract the organic phase with saturated brine. Add dichloromethane to the aqueous phase again and extract with saturated brine again, repeating this process several times. Combine the organic phases, evaporate the solvent, and cool to obtain a pale yellow solid, which is the intermediate.

[0047] (2) Preparation of target temperature-responsive switching surfactants

[0048] 6 mmol of the intermediate and 8.5 mmol of sodium chloroacetate were dissolved in 175 mL of a mixture of ethanol and water (v / v = 7:1), and the mixture was placed in a flask and heated to 95 °C for reaction. The mixture was refluxed with circulating water and reacted for 30 h. After the reaction was complete, the solvent was removed by rotary evaporation. The mixture was washed with ethanol and filtered to remove sodium chloroacetate. The ethanol was then removed by rotary evaporation again. After cooling, a white or pale yellow solid was obtained, which was the target product.

[0049] Example 5

[0050] (1) Preparation of tertiary amine intermediates

[0051] Weigh out 7 mmol of dried stearic acid polyoxyethylene ether, 6.5 mmol of N,N-dimethylglycine, 1 mmol of DMAP, and 5 mmol of EDCI, and add them to a reaction vessel containing 200 mL of dichloromethane. Stir at room temperature for 72 h. Keep the system sealed during the reaction to prevent solvent evaporation and water ingress. After the reaction is complete, extract the organic phase with saturated brine. Add dichloromethane to the aqueous phase again and extract with saturated brine again, repeating this process several times. Combine the organic phases, evaporate the solvent, and cool to obtain a pale yellow solid, which is the intermediate.

[0052] (2) Preparation of target temperature-responsive switching surfactants

[0053] 7 mmol of the intermediate and 10 mmol of sodium chloroacetate were dissolved in 200 mL of a mixture of ethanol and water (v / v = 8:1), and the mixture was placed in a flask and heated to 100 °C for reaction. The reaction was carried out under reflux with circulating water for 36 h. After the reaction was completed, the solvent was removed by rotary evaporation, and the mixture was washed with ethanol and filtered to remove sodium chloroacetate. The ethanol was then removed by rotary evaporation again. After cooling, a white or pale yellow solid was obtained, which was the target product.

[0054] Performance testing

[0055] The surfactants prepared in Examples 1 to 5 were dissolved in water with a mineralization of 100,000 mg / L (CaCl2:NaCl = 4:1 (w / w)) to prepare 0.5% (w / w) surfactant aqueous solutions, which were then used to obtain test solutions.

[0056] To verify the foaming ability, foam stabilizing ability, and temperature-responsive switching properties of the temperature-responsive switching surfactant prepared in this invention, the foaming ability (maximum foam height, H) of the test solutions prepared from the temperature-responsive switching surfactants of Examples 1 to 5 was measured using a Roche foam analyzer at 20°C, 50°C, 80°C, and 120°C. max ) and foam stabilizing ability (half-life, t) 1 / 2 The testing process is as follows:

[0057] The testing process is as follows:

[0058] 1) Set the constant temperature water bath to the test temperature, and rinse the inner wall of the graduated tube with pure water and test solution successively;

[0059] 2) Pour 50 mL of preheated test solution to the set temperature into the graduated tube;

[0060] 3) Use a dropper to draw 200 mL of preheated test solution and place it on the tube rack in a fixed position;

[0061] 4) Allow the solution in the dropper to flow down naturally and record the maximum height of the foam, H. max The time t when the bubble height decays to half of the maximum bubble height 1 / 2 .

[0062] The test results are shown in the table.

[0063] As can be seen from Table 1, the temperature-responsive switching surfactants prepared in Examples 1 to 5 gradually increased and then decreased in foaming height and half-life as the temperature gradually increased and then decreased, proving that they are temperature-responsive.

[0064] Table 1

[0065]

Claims

1. A compound having the structural formula shown in Formula II), Formula II).

2. A method for preparing the compound as described in claim 1, comprising the following steps: 1) Stearic acid polyoxyethylene ether, N,N-dimethylglycine, 4-dimethylaminopyridine and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were added to the first solvent and the reaction was sealed to obtain a first reaction solution containing intermediate compounds. 2) The intermediate compound is purified from the first reaction solution to obtain the intermediate compound, the structural formula of which is shown in Formula I). Equation I); I) The intermediate compound and sodium chloroacetate are dissolved in a second solvent, and the reaction yields a second reaction solution containing the compound; II) The compound is purified from the second reaction solution to obtain the compound.

3. The method according to claim 2, characterized in that, The molar ratio of the stearic acid polyoxyethylene ether, the N,N-dimethylglycine, the 4-dimethylaminopyridine and the 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is (3-7):(2.5-6.5); (0.25-1):(3-5).

4. The method according to claim 2, characterized in that, The molar ratio of the stearic acid polyoxyethylene ether, the N,N-dimethylglycine, the 4-dimethylaminopyridine and the 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is (7-12):(6.5-10):1:(5-12).

5. The method according to claim 2, characterized in that, The sealing reaction takes 24 to 72 hours.

6. The method according to claim 2, characterized in that, The first reaction solution is extracted with saturated brine to produce an aqueous phase and an organic phase. The separated aqueous phase is added to the first solvent and extracted again with saturated brine. This process is repeated multiple times. The organic phases produced by each extraction are combined, and then the first solvent is removed to obtain the intermediate compound.

7. The method according to claim 2, characterized in that, The first solvent is dichloromethane.

8. The method according to claim 2, characterized in that, The molar ratio of the intermediate compound to the sodium chloroacetate is (3 to 7): (3 to 10).

9. The method according to claim 2, characterized in that, The molar ratio of the intermediate compound to the sodium chloroacetate is 1:(1 to 1.4).

10. The method according to claim 2, characterized in that, In step I), the reaction temperature is 80 to 100°C, and the reaction time is 12 to 36 h; and / or The second solvent is a mixture of ethanol and water, wherein the volume ratio of the ethanol to the water is (5-8):1; and / or In step II), the second solvent in the second reaction solution is removed by rotary evaporation, then the sodium chloroacetate is removed by washing with ethanol and filtration, and the compound is obtained by rotary evaporation again to remove the ethanol.

11. The use of the compound according to claim 1 or the compound prepared by the method of any one of claims 2 to 10 as a foaming agent.

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