A temperature-sensitive surfactant, its preparation method, and a foam stabilizer / foaming agent containing it.

Abstract

This invention provides a temperature-sensitive surfactant, its preparation method, and a foam stabilizer / foaming agent containing the same. The structure of the temperature-sensitive surfactant is shown in Formula I), where R is C 12 H 24 n is 10.

Description

Technical Field

[0001] This invention relates to the field of surfactants, and in particular to surfactants that make foams more stable at high temperatures. Background Technology

[0002] As a compressible non-Newtonian fluid, foam fluid has unique structural characteristics and seepage properties, and is widely used in drilling and oil and gas field development. Therefore, it is also known as the "intelligent fluid" in oil fields. Compared with conventional Newtonian fluids, the characteristics of foam fluid are mainly reflected in the following aspects: (1) Low density, and adjustable (0.4~0.9 g / cm³). 3 (1) It can achieve negative pressure drilling, which is beneficial to prevent well leakage; (2) It has high viscosity, low friction and strong sand carrying capacity, which can reduce the occurrence of sand jamming; (3) It uses less liquid and has strong drainage capacity; (4) It is stable when it encounters water and defoams when it encounters oil; (5) It has a good profile control and diversion effect for high and low permeability; (6) It has low filtration loss and is less harmful to water-sensitive formations, which is beneficial to protecting oil and gas layers; (7) It has a good slowing effect; (8) It is safe to operate and usually will not cause downhole fire and explosion accidents, and can also reduce corrosion of drilling tools, etc.

[0003] In the petroleum industry, foam typically refers to aqueous foam, where the liquid phase is water. Common aqueous foam systems consist of a gas phase, a liquid phase, and a surfactant. The gas is the dispersed phase (discontinuous phase), the liquid is the continuous phase, and the surfactant reduces surface tension, enabling foam formation and adsorbing onto the foam liquid film to form a double adsorption layer, thus stabilizing the foam. Because foam systems are thermodynamically metastable, they begin to decay the moment they form and are more prone to instability and collapse under adverse conditions. Temperature-responsive foam refers to foam whose stability can be controlled by temperature. In oil and gas extraction, endowing foam with intelligent responsiveness, allowing it to bubble when the formation temperature is high and defoam when the surface temperature decreases, eliminates the need for defoaming and demulsification processes associated with conventional foam fluids in oil and gas extraction, simplifying the extraction process and significantly reducing costs. Summary of the Invention

[0004] One aspect of the present invention provides a temperature-sensitive surfactant with the configuration shown in Formula I), wherein R is C 12 H 24 n is 10.

[0005]

[0006] The second aspect of the present invention provides a method for preparing a temperature-sensitive surfactant as described in the first aspect of the present invention, comprising the following steps:

[0007] 1) Polyoxyethylene lauryl ether carboxylic acid and diethanolamine are dissolved in acetone to obtain an acetone reaction solution. A catalyst is added dropwise to the acetone reaction solution, and then the temperature is raised to carry out the reaction. After the reaction is completed, the acetone and unreacted diethanolamine are removed to obtain a tertiary amine intermediate.

[0008] 2) The tertiary amine intermediate and sodium chloroacetate were dissolved in a mixed solution of ethanol and water, and then the temperature was raised to carry out the reaction. After the reaction was completed, the ethanol and water were removed to obtain a solid product. The solid product was washed with ethanol and filtered, and then purified by recrystallization with a mixed solution of ethanol and diethyl ether to obtain the temperature-sensitive surfactant.

[0009] In one specific embodiment, in step 1), the reaction temperature is 50 to 80°C and the reaction time is 3 to 9 hours.

[0010] In one specific embodiment, in step 2), the reaction temperature is 50 to 80°C and the reaction time is 6 to 12 hours.

[0011] In one specific embodiment, the molar ratio of the polyoxyethylene lauryl ether carboxylic acid to the ethylenediamine is 1:(1-3), and the molar ratio of the tertiary amine intermediate to the sodium chloroacetate is 1:(1-3).

[0012] In one specific embodiment, the catalyst is SOCl2, and the mass-to-volume ratio of the polyoxyethylene lauryl ether carboxylic acid to the catalyst is 6.84 g:(3-10 ml).

[0013] In one specific embodiment, in step 1), the acetone and unreacted diethanolamine are removed by vacuum distillation; in step 2), the ethanol and water are removed by rotary evaporation.

[0014] In one specific embodiment, the volume ratio of ethanol to water is (3-5):1.

[0015] In one specific embodiment, the volume ratio of ethanol to diethyl ether is (2-4):1.

[0016] The third invention provides a temperature-sensitive foaming agent, which includes a temperature-sensitive surfactant as described in the first invention or a temperature-sensitive surfactant prepared by the method described in any one of the second inventions, and an anionic gemini surfactant.

[0017] In one specific embodiment, the anionic gemini surfactant is at least one of sodium dodecylbenzenesulfonate, sodium α-alkenylsulfonate, and sodium fatty alcohol polyoxyethylene ether sulfate.

[0018] In one specific embodiment, the mass ratio of the thermosensitive surfactant to the anionic gemini surfactant is 3:8 to 10:3.

[0019] In one specific embodiment, the temperature-sensitive foaming agent further includes water, which accounts for 100% of the total mass of the temperature-sensitive foaming agent; the content of the temperature-sensitive surfactant is 3% to 10%; and the content of the anionic gemini surfactant is 3% to 8%.

[0020] The beneficial effects of this invention are:

[0021] The foaming agent prepared by the method of this invention can utilize the temperature difference to have high foaming and foam stabilizing properties when the temperature is high in the formation. After reaching the surface, the temperature decreases and the foaming agent automatically defoams. Furthermore, the temperature-sensitive surfactant and the anionic gemini surfactant in the foaming agent have a synergistic effect, thereby eliminating the defoaming and demulsification processes required in conventional foam fluids for oil and gas extraction, simplifying the oil and gas extraction process, improving the oil and gas reservoir recovery rate, and reducing the oil and gas recovery cost. Detailed Implementation

[0022] The present invention will be further described below with reference to the embodiments. However, the embodiments of the present invention are merely illustrative examples and should not be construed as limiting the present invention under any circumstances.

[0023] Example 1

[0024] (1) Dissolve 6.84 g of polyoxyethylene lauryl ether carboxylic acid and 1.05 g of diethanolamine in 150 ml of acetone. Add 3 ml of SOCl2 as a catalyst into a constant pressure dropping funnel and slowly add it dropwise at ambient temperature. After the addition is complete, raise the temperature to 50 °C for reaction. Use circulating water to cool and control the reaction temperature at 50 °C. The reaction time is 3 h. Remove acetone and unreacted diethanolamine from the obtained reaction solution by vacuum distillation to obtain a tertiary amine intermediate.

[0025] (2) 14.03 g of the tertiary amine intermediate and 1.16 g of sodium chloroacetate were dissolved in 250 ml of a 5:1 mixture of ethanol and water. The mixture was placed in a three-necked flask and heated to 50 °C for reaction. The reaction temperature was controlled at 50 °C using circulating water cooling for 6 h. After the reaction, ethanol and water were removed by rotary evaporation. The resulting solid product was washed with ethanol and filtered. Then, it was purified by recrystallization with a 2:1 mixture of ethanol and diethyl ether to obtain Gemini polyoxyethylene lauryl ether carboxylate betaine. The structural formula of Gemini polyoxyethylene lauryl ether carboxylate betaine is shown in Formula I), where R is C 12 H 24 n is 10.

[0026] The yield of Gemini polyoxyethylene lauryl ether carboxylate betaine was 80%.

[0027]

[0028] The structure of polyoxyethylene lauryl ether carboxylic acid is shown in formula II), where R is C 12 H 24 n=10

[0029]

[0030] Example 2

[0031] (1) Dissolve 6.84 g of polyoxyethylene lauryl ether carboxylic acid (its structural formula is as in Example 1) and 2.1 g of diethanolamine in 150 ml of acetone. Add 6 ml of SOCl2 as a catalyst into a constant pressure dropping funnel and slowly add it dropwise at ambient temperature. After the addition is complete, raise the temperature to 65 °C for reaction. Use circulating water to cool and control the reaction temperature at 65 °C. The reaction time is 6 h. Remove acetone and unreacted diethanolamine from the obtained reaction solution by vacuum distillation to obtain a tertiary amine intermediate.

[0032] (2) 14.03 g of the tertiary amine intermediate and 2.32 g of sodium chloroacetate were dissolved in 250 ml of a 4:1 mixture of ethanol and water. The mixture was placed in a three-necked flask and heated to 65 °C for reaction. The reaction temperature was controlled at 65 °C using circulating water cooling for 9 h. After the reaction, ethanol and water were removed by rotary evaporation. The resulting solid product was washed with ethanol and filtered. Then, it was purified by recrystallization with a 3:1 mixture of ethanol and diethyl ether to obtain Gemini polyoxyethylene lauryl ether carboxylate betaine. The structural formula of Gemini polyoxyethylene lauryl ether carboxylate betaine is shown in Formula I) in Example 1, where R is C 12 H 24 n is 10.

[0033] The yield of Gemini polyoxyethylene lauryl ether carboxylate betaine was 83%.

[0034] Example 3

[0035] (1) Dissolve 6.84 g of polyoxyethylene lauryl ether carboxylic acid (its structural formula is as in Example 1) and 3.15 g of diethanolamine in 150 ml of acetone. Add 10 ml of SOCl2 as a catalyst into a constant pressure dropping funnel and slowly add it dropwise at ambient temperature. After the addition is complete, raise the temperature to 80 °C for reaction. Use circulating water to cool and control the reaction temperature at 80 °C. The reaction time is 9 h. Remove acetone and unreacted diethanolamine from the obtained reaction solution by vacuum distillation to obtain a tertiary amine intermediate.

[0036] (2) 14.03 g of the tertiary amine intermediate product and 3.48 g of sodium chloroacetate were dissolved in 250 ml of a 3:1 mixture of ethanol and water. The mixture was placed in a three-necked flask and heated to 80 °C for reaction. The reaction temperature was controlled at 80 °C using circulating water cooling for 12 h. After the reaction, ethanol and water were removed by rotary evaporation. The resulting solid product was washed with ethanol and filtered. Then, it was purified by recrystallization with a 4:1 mixture of ethanol and diethyl ether to obtain Gemini polyoxyethylene lauryl ether carboxylate betaine. The structural formula of Gemini polyoxyethylene lauryl ether carboxylate betaine is shown in Formula I) in Example 1, where R is C 12 H 24 n is 10.

[0037] The yield of the obtained Gemini polyoxyethylene lauryl ether carboxylate betaine was 85%.

[0038] The Gemini polyoxyethylene lauryl ether carboxylate betaine prepared in Example 3 had the highest yield. Therefore, the Gemini polyoxyethylene lauryl ether carboxylate betaine prepared in Example 3 was selected as a temperature-sensitive surfactant to prepare a temperature-sensitive foaming agent. The preparation method of the temperature-sensitive foaming agent for oil and gas development provided by this invention is as follows:

[0039] Example 4

[0040] Taking the total mass of the temperature-sensitive foaming agent as 100%, 3% of the temperature-sensitive surfactant and 3% of sodium dodecylbenzenesulfonate were slowly added to a stainless steel reactor, followed by the addition of mineralized water with a mineralization degree of 100,000 mg / L (mass ratio of CaCl2 to NaCl of 4:1) as a solvent. The mixture was heated to 50°C and stirred at low speed for 60 minutes to obtain the temperature-sensitive foaming agent.

[0041] Example 5

[0042] Taking the total mass of the temperature-sensitive foaming agent as 100%, 6% of the temperature-sensitive surfactant and 5% of sodium dodecylbenzenesulfonate were slowly added to a stainless steel reactor, followed by the addition of mineralized water with a mineralization degree of 100,000 mg / L (mass ratio of CaCl2 to NaCl of 4:1) as a solvent. The mixture was heated to 60°C and stirred at low speed for 40 minutes to obtain the temperature-sensitive foaming agent.

[0043] Example 6

[0044] Taking the total mass of the temperature-sensitive foaming agent as 100%, 10% of the temperature-sensitive surfactant and 8% of sodium dodecylbenzenesulfonate were slowly added to a stainless steel reactor. Then, mineralized water with a mineralization degree of 100,000 mg / L (mass ratio of CaCl2 to NaCl of 4:1) was added as a solvent. The mixture was heated to 70°C and stirred at low speed for 20 minutes to obtain the temperature-sensitive foaming agent.

[0045] Example 7

[0046] Taking the total mass of the temperature-sensitive foaming agent as 100%, 3% of the temperature-sensitive surfactant and 3% of sodium α-olefin sulfonate were slowly added to a stainless steel reactor. Then, mineralized water with a mineralization degree of 100,000 mg / L (mass ratio of CaCl2 to NaCl of 4:1) was added as a solvent. The mixture was heated to 50°C and stirred at low speed for 60 minutes to obtain the temperature-sensitive foaming agent.

[0047] Example 8

[0048] Taking the total mass of the temperature-sensitive foaming agent as 100%, 6% of the temperature-sensitive surfactant and 5% of sodium α-olefin sulfonate were slowly added to a stainless steel reactor. Then, mineralized water with a mineralization degree of 100,000 mg / L (mass ratio of CaCl2 to NaCl of 4:1) was added as a solvent. The mixture was heated to 60°C and stirred at low speed for 40 minutes to obtain the temperature-sensitive foaming agent.

[0049] Example 9

[0050] Taking the total mass of the temperature-sensitive foaming agent as 100%, 10% of the temperature-sensitive surfactant and 8% of sodium α-olefin sulfonate were slowly added to a stainless steel reactor. Then, mineralized water with a mineralization degree of 100,000 mg / L (mass ratio of CaCl2 to NaCl of 4:1) was added as a solvent. The mixture was heated to 70°C and stirred at low speed for 20 minutes to obtain the temperature-sensitive foaming agent.

[0051] Example 10

[0052] Taking the total mass of the temperature-sensitive foaming agent as 100%, 3% of the temperature-sensitive surfactant and 3% of the fatty alcohol polyoxyethylene ether sodium sulfate were slowly added to a stainless steel reactor. Then, mineralized water with a mineralization degree of 100,000 mg / L (mass ratio of CaCl2 to NaCl of 4:1) was added as a solvent. The mixture was heated to 50°C and stirred at low speed for 60 minutes to obtain the temperature-sensitive foaming agent.

[0053] Example 11

[0054] Taking the total mass of the temperature-sensitive foaming agent as 100%, 6% of the temperature-sensitive surfactant and 5% of the fatty alcohol polyoxyethylene ether sodium sulfate were slowly added to a stainless steel reactor. Then, mineralized water with a mineralization degree of 100,000 mg / L (mass ratio of CaCl2 to NaCl of 4:1) was added as a solvent. The mixture was heated to 60°C and stirred at low speed for 40 minutes to obtain the temperature-sensitive foaming agent.

[0055] Example 12

[0056] Taking the total mass of the temperature-sensitive foaming agent as 100%, 10% of the temperature-sensitive surfactant and 8% of the fatty alcohol polyoxyethylene ether sodium sulfate were slowly added to a stainless steel reactor. Then, mineralized water with a mineralization degree of 100,000 mg / L (the mass ratio of CaCl2 to NaCl is 4:1) was added as a solvent. The mixture was heated to 70°C and stirred at low speed for 20 minutes to obtain the temperature-sensitive foaming agent.

[0057] To verify the foaming ability, foam stabilization ability, and temperature responsiveness of the foaming agent used in foam drainage gas extraction according to the present invention, the temperature-sensitive foaming agents prepared in Examples 4 to 12 were used as the test temperature-sensitive foaming agents. A Roche foam analyzer was used to measure the foaming ability (maximum foam height, H) at 20°C, 40°C, 70°C, and 90°C. max ) and foam stabilizing ability (half-life, t 1 / 2 The specific testing process is as follows:

[0058] (1) Turn on the thermostat. When the test temperature is reached, turn on the water bath preheating jacket to stabilize the test temperature.

[0059] (2) Rinse the inner wall of the graduated tube with distilled water, and then rinse the tube wall with the temperature-sensitive foaming agent to be tested. The rinsing must be complete.

[0060] (3) Close the graduated tube stopcock, inject 50ml of the temperature-sensitive foaming agent to be tested using the dropper, and preheat the temperature-sensitive foaming agent to be tested to the test temperature;

[0061] (4) Fill the dropper with 200ml of the temperature-sensitive foaming agent to be tested, and preheat the temperature-sensitive foaming agent to be tested to the test temperature in the dropper.

[0062] (5) Place the dropper on the tube rack and make it perpendicular to the cross section of the graduated tube. The outlet of the dropper should be placed on the 900mm graduation line so that the temperature-sensitive foaming agent to be tested flows to the center of the graduated tube.

[0063] (6) Open the stopcock of the drip tube to allow the temperature-sensitive foaming agent to be tested to flow down. When the temperature-sensitive foaming agent to be tested has finished flowing out of the drip tube, immediately start the stopwatch and measure the foam height, then record the maximum foam height H. max The time t when the bubble height decays to half of the maximum bubble height 1 / 2 This is used to evaluate the foaming ability and foam stabilizing ability of the temperature-sensitive foaming agent under test, respectively.

[0064] (7) Repeat the above experiment three times and take the average value. Before each experiment, the container wall must be cleaned to avoid affecting the accuracy of the data.

[0065] The test results are shown in Table 1.

[0066] Table 1. Foaming ability, foam stabilization ability, and foam performance at different temperatures of the tested temperature-sensitive foaming agents.

[0067]

[0068] As can be seen from Table 1, the temperature-responsive foaming agents prepared in Examples 4 to 12 have poor foaming and foam stability at a lower temperature of 20°C. As the temperature increases, their initial foam height and half-life gradually increase, demonstrating the synergistic effect of the two surfactants and proving that they have temperature responsiveness. The foam produced by the corresponding foam system is more stable at high temperatures, and the stability of the foam can be adjusted within the temperature range of 20°C to 90°C.

[0069] While the present invention has been described with reference to specific embodiments, those skilled in the art will understand that various changes can be made without departing from the true spirit and scope of the invention. Furthermore, numerous modifications can be made to the subject, spirit, and scope of the invention to suit specific situations, materials, material compositions, and methods. All such modifications are included within the scope of the claims of the present invention.

Claims

1. A temperature-sensitive surfactant, the structural formula of which is shown in Formula I), wherein, R is C 12 H 24 n is 10. Formula I).

2. A method for preparing the temperature-sensitive surfactant as described in claim 1, comprising the following steps: 1) Polyoxyethylene lauryl ether carboxylic acid and diethanolamine are dissolved in acetone to obtain an acetone reaction solution. A catalyst is added dropwise to the acetone reaction solution, and then the temperature is raised to carry out the reaction. After the reaction is completed, the acetone and unreacted diethanolamine are removed to obtain a tertiary amine intermediate. 2) The tertiary amine intermediate and sodium chloroacetate were dissolved in a mixed solution of ethanol and water, and then the temperature was raised to carry out the reaction. After the reaction was completed, the ethanol and water were removed to obtain a solid product. The solid product was washed with ethanol and filtered, and then purified by recrystallization with a mixed solution of ethanol and diethyl ether to obtain the temperature-sensitive surfactant.

3. The method according to claim 2, characterized in that, In step 1), the reaction temperature is 50 to 80°C, and the reaction time is 3 to 9 hours; and / or In step 2), the reaction temperature is 50 to 80°C and the reaction time is 6 to 12 hours.

4. The method according to claim 2, characterized in that, The molar ratio of the tertiary amine intermediate to the sodium chloroacetate is 1:(1-3).

5. The method according to claim 2, characterized in that, The catalyst is SOCl2, and the mass-to-volume ratio of the polyoxyethylene lauryl ether carboxylic acid to the catalyst is 6.84 g: (3-10 ml).

6. The method according to claim 2, characterized in that, In step 1), the acetone and unreacted diethanolamine are removed by vacuum distillation; in step 2), the ethanol and water are removed by rotary evaporation. In step 2), the volume ratio of ethanol to water is (3-5):1; In step 2), the volume ratio of ethanol to diethyl ether is (2-4):

1.

7. A temperature-sensitive foaming agent comprising the temperature-sensitive surfactant as described in claim 1 or the temperature-sensitive surfactant prepared by the method as described in any one of claims 2 to 6, and an anionic gemini surfactant.

8. The temperature-sensitive foaming agent according to claim 7, characterized in that, The anionic gemini surfactant is at least one of sodium dodecylbenzenesulfonate, sodium α-alkenylsulfonate, and sodium fatty alcohol polyoxyethylene ether sulfate.

9. The temperature-sensitive foaming agent according to claim 7, characterized in that, The mass ratio of the thermosensitive surfactant to the anionic gemini surfactant is 3:8 to 10:

3.

10. The temperature-sensitive foaming agent according to claim 7, characterized in that, The temperature-sensitive foaming agent also includes water, which accounts for 100% of the total mass of the temperature-sensitive foaming agent; the content of the temperature-sensitive surfactant is 3% to 10%; and the content of the anionic gemini surfactant is 3% to 8%.

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