High-temperature-resistant and salt-resistant foaming agent for oil and gas fields and preparation method thereof

Abstract

The invention relates to the technical field of foaming agents for oil and gas fields, and discloses a high-temperature-resistant and salt-resistant foaming agent for oil and gas fields and a preparation method thereof. According to the invention, the sulfonate acrylate intermediate and N, N-dialkyl ethane-1, 2-diamine are used as reactants, and a Michael addition polymerization reaction is carried out, so that the obtained foaming agent contains a hydrophobic alkyl group and hydrophilic ureido and sulfonate groups, has a very high surface activity effect, can effectively reduce the surface tension of water, is strong in foaming performance, and can be used for preparing the foaming agent. The half-life period is long, and foam is stable. The foaming agent still keeps very high foamability and salt resistance in formation water with high salinity. And the foaming agent is a macromolecular polymer, has good heat resistance, is not easy to thermally decompose, still keeps very high foam volume and foam half-life period after being subjected to high-temperature thermal aging, and has very good foaming performance. The method has good practical application in storage and exploitation of high-temperature and high-salt oil and gas fields.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field foaming agents, and specifically to a high-temperature resistant and salt-resistant foaming agent for oil and gas fields and a preparation method thereof. Background Art

[0002] Foam flooding is an enhanced oil recovery technology that uses foam as a displacing agent. By injecting foam, the sweep efficiency of the reservoir is improved, thereby increasing the crude oil production. Among them, the foaming agent plays a key role in foam flooding technology and oil recovery. Usually, the foaming agents used in oil and gas field development are surfactants such as sulfonates, betaines, and sulfonate polyoxyethylene ethers. However, these foaming agents have poor high-temperature resistance, are prone to thermal decomposition, and have poor salt resistance, and cannot meet the actual application in high-temperature and high-salt reservoir exploitation.

[0003] Developing high-performance foaming agents is a research hotspot. The patent application document with the publication number CN117903777A discloses a foaming agent for oil fields prepared from composite base materials, nano base materials, sodium dodecylbenzenesulfonate, glycerol, chelating agents, lower alcohols, etc. Although the foaming agent has a high-temperature resistance effect, the components of the foaming agent are relatively complex, and the salt resistance of the foaming agent is not improved. Summary of the Invention

[0004] The technical problem solved by the present invention: The present invention provides a foaming agent for oil and gas fields with good high-temperature resistance and excellent salt resistance.

[0005] The technical solution of the present invention: A preparation method of a high-temperature resistant and salt-resistant foaming agent for oil and gas fields:

[0006] (1) Add a solvent, isocyanatoethyl methacrylate (CAS registration number: 34730-59-1), 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt (CAS registration number: 30674-80-7), and dibutyltin dilaurate to a reaction vessel. Under a nitrogen atmosphere, stir and react at 20-40 °C for 2-5 h, then carry out vacuum distillation, wash with petroleum ether, and recrystallize the product in an ethanol aqueous solution to obtain a sulfonate acrylate intermediate. The reaction formula is:

[0007]

[0008] (2) Add ethanol, water, sulfonate acrylate intermediate, and N,N-dialkylethane-1,2-diamine to a reaction vessel equipped with a condenser reflux tube. Stir and react at 60-75 °C for 18-24 h, dry to remove ethanol and water, wash with acetone, and dry to obtain a high-temperature resistant and salt-resistant foaming agent for oil and gas fields. The reaction formula is:

[0009]

[0010] Preferably, the solvent in (1) is dichloromethane or tetrahydrofuran.

[0011] Preferably, the molar ratio of isocyanatoethyl methacrylate, sodium 2-[(2-aminoethyl)amino]ethanesulfonate, and dibutyltin dilaurate in (1) is (2 - 2.2):1:(0.003 - 0.005).

[0012] Preferably, the volume ratio of ethanol to water in (2) is 1:(0.8 - 1.4).

[0013] Preferably, the molar ratio of the sulfonate acrylate intermediate to N,N-dialkylethane-1,2-diamine in (2) is 1:(0.9 - 1.2).

[0014] The beneficial technical effects of the present invention: The present invention uses a sulfonate acrylate intermediate and N,N-dialkylethane-1,2-diamine as reactants. Through a Michael addition polymerization reaction, the obtained foaming agent contains hydrophobic alkyl groups, as well as hydrophilic ureido and sulfonate groups, and has a very high surface activity effect. It can effectively reduce the surface tension of water, has strong foaming performance, a long half-life time, and stable foam.

[0015] The foaming agent of the present invention still maintains very high foaming performance and salt resistance in high salinity formation water. And the foaming agent is a macromolecular polymer with good heat resistance and is not easily thermally decomposed. After high-temperature thermal aging, the foaming agent still maintains a very high foam volume and foam half-life, and has very good foaming performance. It has good practical applications in foam flooding exploitation in high-temperature and high-salt oil and gas field reservoirs. Specific Embodiments

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0017] Prepare N,N-dialkylethane-1,2-diamine according to the method in the journal Bioorganic Chemistry, 101(2020)103965, the literature "Systematic research of H2dedpa derivatives as potent inhibitors of New DelhiMetallo-β-lactamase-1".

[0018] Add 20 mL of N,N-dimethylformamide, 8.32 mmol of ethylenediamine, and 18.3 mmol of 1-bromohexane to a reaction vessel. React at room temperature for 28 h. Remove N,N-dimethylformamide by vacuum distillation. Wash the product with saturated sodium hydroxide solution, and then recrystallize it from an aqueous ethanol solution with a volume fraction of 70% to obtain N,N-dihexylethyl-1,2-diamine. The structural formula is

[0019] Add 20 mL of N,N-dimethylformamide, 8.32 mmol of ethylenediamine, and 18.3 mmol of 1-bromoheptane to a reaction vessel. React at room temperature for 28 h. Remove N,N-dimethylformamide by vacuum distillation. Wash the product with saturated sodium hydroxide solution, and then recrystallize it from an aqueous ethanol solution with a volume fraction of 70% to obtain N,N-diheptylethyl-1,2-diamine.

[0020] Add 20 mL of N,N-dimethylformamide, 8.32 mmol of ethylenediamine, and 18.3 mmol of 1-bromooctane to a reaction vessel. React at room temperature for 28 h. Remove N,N-dimethylformamide by vacuum distillation. Wash the product with saturated sodium hydroxide solution, and then recrystallize it from an aqueous ethanol solution with a volume fraction of 70% to obtain N,N-dihexylethyl-1,2-diamine. The structural formula is

[0021] Example 1:

[0022] (1) Add 30 mL of dichloromethane, 20 mmol of isocyanatoethyl methacrylate, 10 mmol of 2-[(2-aminoethyl)amino]ethanesulfonate sodium salt, and 0.05 mmol of dibutyltin dilaurate to a reaction vessel. Stir and react in nitrogen at 25 °C for 5 h. Perform vacuum distillation and wash with petroleum ether. Recrystallize the product from an aqueous ethanol solution with a volume fraction of 50% to obtain a sulfonate acrylate intermediate.

[0023] (2) Add 25 mL of ethanol, 30 mL of water, 10 mmol of the sulfonate acrylate intermediate, and 10 mmol of N,N-dihexylethyl-1,2-diamine to a reaction vessel equipped with a condenser reflux tube. Stir and react at 75 °C for 18 h. Dry to remove ethanol and water, wash with acetone, and dry to obtain a high-temperature and salt-resistant foaming agent for oil and gas fields.

[0024] Example 2:

[0025] (1) Add 30 mL of dichloromethane, 22 mmol of isocyanatoethyl methacrylate, 10 mmol of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt, and 0.04 mmol of dibutyltin dilaurate to a reaction vessel. Stir the reaction in nitrogen at 20 °C for 5 h, then perform vacuum distillation and wash with petroleum ether. Recrystallize the product from an aqueous ethanol solution with a volume fraction of 50% to obtain the sulfonate acrylate intermediate.

[0026] (2) Add 25 mL of ethanol, 20 mL of water, 10 mmol of the sulfonate acrylate intermediate, and 9 mmol of N,N-diheptylethane-1,2-diamine to a reaction vessel equipped with a condenser. Stir the reaction at 70 °C for 18 h, dry to remove ethanol and water, wash with acetone, and dry to obtain a high-temperature and salt-resistant foaming agent for oil and gas fields.

[0027] Example 3:

[0028] (1) Add 25 mL of tetrahydrofuran, 20 mmol of isocyanatoethyl methacrylate, 10 mmol of 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt, and 0.03 mmol of dibutyltin dilaurate to a reaction vessel. Stir the reaction in nitrogen at 40 °C for 2 h, then perform vacuum distillation and wash with petroleum ether. Recrystallize the product from an aqueous ethanol solution with a volume fraction of 50% to obtain the sulfonate acrylate intermediate.

[0029] (2) Add 25 mL of ethanol, 35 mL of water, 10 mmol of the sulfonate acrylate intermediate, and 12 mmol of N,N-dioctylethane-1,2-diamine to a reaction vessel equipped with a condenser. Stir the reaction at 60 °C for 24 h, dry to remove ethanol and water, wash with acetone, and dry to obtain a high-temperature and salt-resistant foaming agent for oil and gas fields.

[0030] Comparative Example 1 uses the sulfonate acrylate intermediate as the foaming agent.

[0031] Comparative Example 2:

[0032] (1) Add 25 mL of ethanol, 30 mL of water, 10 mmol of ethylene glycol dimethacrylate (structural formula is ) and 10 mmol of N,N-dihexylethyl-1,2-diamine to a reaction vessel equipped with a condenser. Stir the reaction at 75 °C for 18 h, dry to remove ethanol and water, wash with acetone, and dry to obtain the foaming agent.

[0033] Comparative Example 3:

[0034] (1) Add 25 mL of ethanol, 30 mL of water, 10 mmol of sulfonate acrylate intermediate (prepared in the same way as in Example 1), and 10 mmol of N,N'-dimethylethylenediamine (structural formula is ) to a reaction vessel equipped with a condensing reflux tube, stir and react at 75 °C for 18 h, dry to remove ethanol and water, wash with acetone, and dry to obtain a foaming agent.

[0035] Add 0.3 g of the foaming agent to 1 L of distilled water, stir for 10 min, and measure the surface tension at room temperature using a surface tension meter. The test results are shown in Table 1.

[0036] Table 1 Surface Tension Test of Foaming Agent

[0037] Surface tension (mN / m) Example 1 37.22 Example 2 35.79 Example 3 35.17 Comparative Example 1 47.26 Comparative Example 2 68.42 Comparative Example 3 44.73

[0038] Add 0.5 g of the foaming agent to 100 mL of distilled water, stir for 10 min to prepare a foaming agent solution. Add the solution to a high-temperature and high-pressure foam evaluation instrument, introduce nitrogen, control the pressure to 30 MPa, stir for 2 min, and control the rotation speed to 2000 r / min to measure the foam volume and foam half-life. The test results are shown in Table 2.

[0039] Table 2 Performance Test of Foaming Agent

[0040] Foam volume (mL) Foam half-life (min) Example 1 450 48 Example 2 826 67 Example 3 695 72 Comparative Example 1 79 5 Comparative Example 2 - - Comparative Example 3 167 19

[0041] After testing, in Examples 1-3, using sulfonate acrylate intermediate and N,N-dialkylethane-1,2-diamine as reactants, through Michael addition polymerization reaction, the obtained foaming agent contains hydrophobic alkyl groups, as well as hydrophilic urea groups and sulfonate groups, has a very high surface activity effect, can effectively reduce the surface tension of water, has strong foaming performance, a long half-life time, and stable foam.

[0042] In Comparative Example 1, using sulfonate acrylate intermediate as the foaming agent, the foaming performance is very poor. In Comparative Example 2, ethylene glycol dimethacrylate and N,N-dihexylethyl-1,2-diamine are subjected to addition polymerization reaction, and the obtained foaming agent does not contain sulfonic acid groups and hardly has foaming performance. The foaming agent prepared in Comparative Example 3 does not contain long alkyl chains, has a low surface activity effect, and very poor foaming performance.

[0043] Add 0.5 g of the foaming agent to 100 mL of formation water (salinity 26437 mg / L), stir for 10 min to prepare a foaming agent solution. Add the solution to a high-temperature and high-pressure foam evaluation instrument, introduce nitrogen, control the pressure to 30 MPa, stir for 2 min, and control the rotation speed to 2000 r / min to measure the foam volume and foam half-life. The test results are shown in Table 3.

[0044] Table 3 Salt Resistance Performance Test of Foaming Agents

[0045] Foam volume (mL) Foam half-life (min) Example 1 348 41 Example 2 615 60 Example 3 527 62 Comparative Example 1 43 3 Comparative Example 2 - - Comparative Example 3 103 12

[0046] After testing, the foaming agents prepared in Examples 1 - 3 still maintained high foaming performance in high salinity formation water, with large foam volume, long foam half-life, and good salt resistance performance.

[0047] The foaming agents of Comparative Example 1 and Comparative Example 3 had poor salt resistance performance. In high salinity formation water, their foaming performance was not good, and the decline in foam volume and foam half-life was relatively large.

[0048] Place the foaming agent in an oven and keep it at 80 °C for 120 h. After cooling to room temperature, take 0.5 g of the foaming agent and add it to 100 mL of distilled water, stir for 10 min to prepare a foaming agent solution. Add the solution to a high-temperature and high-pressure foam evaluation instrument, introduce nitrogen gas, control the pressure to 30 MPa, stir for 2 min, and control the rotation speed to 2000 r / min to test the foam volume and foam half-life. The test results are shown in Table 4.

[0049] Table 4 High Temperature Resistance Performance Test of Foaming Agents

[0050] Foam volume (mL) Foam half-life (min) Example 1 429 43 Example 2 779 59 Example 3 661 65 Comparative Example 1 33 2 Comparative Example 2 - - Comparative Example 3 154 17

[0051] After testing, compared with the small molecule compound of Comparative Example 1, the foaming agents of Examples 1 - 3 are macromolecular polymers with better heat resistance and are not easily thermally decomposed. After high-temperature heat treatment, the foaming agents still maintain high foam volume and foam half-life, and the foaming performance is very good.

[0052] Weigh 0.3 - 1.2 g of the foaming agent (prepared in Example 1) and add it to 1 L of distilled water, stir for 10 min, and measure the surface tension at room temperature using a surface tension meter. The test results are shown in Table 5.

[0053] Table 5 Surface Tension Test of Foaming Agents with Different Dosages

[0054] Dosage (g) Surface tension (mN / m) 0.3 37.22 0.5 28.33 0.7 24.17 1 22.94 1.2 22.60

[0055] Add 0.5 - 1.5 g of the foaming agent to 100 mL of distilled water, stir for 10 min to prepare a foaming agent solution. Add the solution to a high-temperature and high-pressure foam evaluation instrument, introduce nitrogen gas, control the pressure to 30 MPa, stir for 2 min, and control the rotation speed to 2000 r / min to test the foam volume and foam half-life. The test results are shown in Table 6.

[0056] Table 6 Foaming Performance Test of Foaming Agents with Different Dosages

[0057] Dosage of foaming agent (g) Foam volume (mL) Foam half-life (min) 0.5 450 48 0.75 623 64 1 745 51 1.25 821 47 1.5 792 45

[0058] After testing, the solutions prepared with different dosages of foaming agents uniformly exhibit low surface tension, large foam volume, long foam half-life, and good foaming performance.

[0059] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a high temperature resistant and salt resistant foaming agent for oil and gas fields, characterized in that: The preparation method comprises: adding ethanol, water, sulfonate acrylate intermediate and N,N-dialkylethane-1,2-diamine into a reaction container equipped with a condensation reflux tube, stirring for reaction, drying to remove ethanol and water, washing with acetone, and drying to obtain a high temperature resistant and salt resistant foaming agent for oil and gas fields; The structural formula of the sulfonate acrylate intermediate is: The structural formula of N,N-dialkylethane-1,2-diamine is: n is 6, 7 or 8.

2. The method for preparing the high temperature resistant and salt resistant foaming agent for oil and gas fields according to claim 1, characterized in that: The volume ratio of the ethanol to water is 1:(0.8-1.4).

3. The method for preparing the high temperature resistant and salt resistant foaming agent for oil and gas fields according to claim 1, characterized in that: The molar ratio of the sulfonate acrylate intermediate to N,N-dialkylethane-1,2-diamine is 1:(0.9-1.2).

4. The method for preparing the high temperature resistant and salt resistant foaming agent for oil and gas fields according to claim 1, characterized in that: The reaction temperature is 60-75°C and the reaction time is 18-24h.

5. The method for preparing the high temperature resistant and salt resistant foaming agent for oil and gas fields according to claim 1, characterized in that: The preparation method of the sulfonate acrylate intermediate comprises the following steps: adding a solvent, isocyanoethyl methacrylate, 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and dibutyltin dilaurate into a reaction container, reacting in a nitrogen atmosphere, performing reduced pressure distillation, washing with petroleum ether, and recrystallizing the product in an ethanol aqueous solution to obtain the sulfonate acrylate intermediate.

6. The method for preparing the high temperature resistant and salt resistant foaming agent for oil and gas fields according to claim 5, characterized in that: The solvent is dichloromethane or tetrahydrofuran.

7. The method for preparing the high temperature resistant and salt resistant foaming agent for oil and gas fields according to claim 5, characterized in that: The molar ratio of isocyanoethyl methacrylate, 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt and dibutyltin dilaurate is (2-2.2):1:(0.003-0.005).

8. The method for preparing the high temperature resistant and salt resistant foaming agent for oil and gas fields according to claim 5, characterized in that: The reaction temperature is 20-40°C and the reaction time is 2-5h.

9. A high temperature resistant and salt resistant foaming agent for oil and gas fields obtained by the preparation method according to any one of claims 1 to 8.

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