Foam scrubbing agent composition of CO2 / N2 switch and application

Abstract

The invention discloses a foam scrubbing agent composition for a CO2 / N2 switch and application, and belongs to the technical field of chemical agents for gas wells. The foam scrubbing agent composition contains an N '-propyl betaine surfactant, a Gemini quaternary ammonium salt surfactant and an amino acid surfactant, and the N'-propyl betaine surfactant has a chemical structure as follows: # imgabs0 # n is a natural number between 11 and 16. According to the foam scrubbing agent composition disclosed by the invention, the components can interact and generate a supramolecular compound under the initiation of CO2, so that the association and binding force to water molecules are effectively improved, and the requirements of high temperature, mineralization degree and foaming and foam stabilizing during foam scrubbing of a gas well containing condensate oil are met; and the generated supramolecular compound can be reversely and rapidly dissociated and self-defoamed through N2 initiation, so that the efficient and convenient foam scrubbing effect is achieved.

Description

Technical Field

[0001] This application belongs to the technical field of gas well foam drainage, and particularly relates to a foam drainage agent composition with a CO 2 / N 2 switch and its application. Background Art

[0002] Foam drainage has become a common technical measure for solving bottom-hole liquid accumulation in gas wells due to its advantages such as simple equipment, convenient operation, low cost, and good effect. Foam drainage is to inject a foam drainage agent into the bottom hole, so that during the vertical flow of the gas-liquid two-phase mixture, a large amount of water-containing foam is generated and carried to the ground with the gas flow, thereby achieving the purpose of removing bottom-hole liquid accumulation. However, common foam drainage agents can achieve good liquid-carrying effects. However, after the foamy formation water is carried to the ground, an antifoaming agent needs to be added through a filling device to separate the gas and water, which may increase costs and may cause problems such as slow and incomplete defoaming. Therefore, it is particularly important to design and prepare a switchable foam drainage agent that can meet high temperature, high condensate oil, and high salinity.

[0003] Currently, pH, light, temperature, CO 2 / N 2 and other switchable foam drainage agents have been disclosed in the related art. Among them, the CO 2 / N 2 switchable foam drainage agent has become a hot spot due to its advantages of simple operation and low cost. For example, a gas well foam drainage agent composition disclosed in the patented technology with the publication number CN 110791273 B uses an alkyl polyoxyethylene ether tertiary amine composite anionic surfactant with CO 2 / N 2 response performance, so that the gas well foam drainage agent composition has CO 2 / N 2 switching performance and good foaming, foam stabilizing, and liquid-carrying capabilities at the same time.

[0004] However, when a tertiary amine-based foam drainage agent with a CO 2 / N 2 switch such as the above is used in the field, it may cause a problem of poor response sensitivity due to the low CO 2 absorption capacity and reaction rate of the tertiary amine. Amidine compounds have better CO 2 responsiveness and are expected to solve the problem of poor response performance of tertiary amine-based foam drainage agents. However, common amidine compounds used for foaming generally have very poor foam stabilizing ability when used for foam drainage at 80°C, high salinity, and condensate oil content, and it is very difficult to improve the foam stabilizing performance by compounding with other types of surfactants (such as anionic and non-ionic surfactants), resulting in their failure to be successfully used in gas well foam drainage operations. Summary of the Invention

[0005] This application discloses a foam drainage agent composition for a CO 2 / N 2 switch and its application, which solves the technical problems that the response effect of the tertiary amine foam drainage agent for the CO 2 / N 2 switch is not ideal, the temperature resistance, salt resistance and oil resistance of common amidine compounds are poor, and the combination effect with other types of foaming agents is not good.

[0006] To achieve the above object, the technical solution adopted in this application is:

[0007] The first aspect of this application provides a foam drainage agent composition for a CO 2 / N 2 switch. This foam drainage agent composition for the CO 2 / N 2 switch contains N'-propyl betaine surfactant, Gemini quaternary ammonium salt surfactant and amino acid surfactant;

[0008] Among them, the N'-propyl betaine surfactant has the chemical structure (1):

[0009]

[0010] n is a natural number between 11 and 16.

[0011] According to the foam drainage agent composition disclosed in this application, the molar ratio of the N'-propyl betaine surfactant, Gemini quaternary ammonium salt surfactant and amino acid surfactant is 1:1:1.

[0012] According to the foam drainage agent composition disclosed in this application, the Gemini quaternary ammonium salt surfactant has the chemical structure (2):

[0013]

[0014] Among them, R 1 is C 11 -C 15 alkyl.

[0015] According to the foam drainage agent composition disclosed in this application, the amino acid surfactant is selected from one of sodium lauroyl glutamate surfactant, sodium lauroyl glycinate surfactant, and sodium lauroyl lysinate surfactant.

[0016] According to the foam drainage agent composition disclosed in this application, the sodium lauroyl glutamate surfactant has the chemical structure (3):

[0017]

[0018] Among them, R2 is C 11 alkyl group.

[0019] According to the foam drainage agent composition disclosed in the present application, the N'-propyl betaine surfactant, Gemini quaternary ammonium salt surfactant and amino acid surfactant can form a supramolecular complex with chemical structure (4) in an aqueous system containing CO 2 :

[0020]

[0021] According to the foam drainage agent composition disclosed in the present application, the preparation method of the N'-propyl betaine surfactant includes:

[0022] a step of subjecting a bromohydrin with chemical structure (5) to a sulfonation reaction with chlorosulfonic acid and then adding a sodium salt to prepare sodium bromoalkyl sulfonate;

[0023]

[0024] a step of subjecting the sodium bromoalkyl sulfonate to a bromoalkylation reaction with 3-dimethylaminopropylamine to prepare an intermediate compound;

[0025]

[0026] and a step of subjecting the intermediate compound, 1,1-dimethoxy-N,N-dimethylethylamine and ethanol to an amidine formation reaction to prepare a target product;

[0027]

[0028] The second aspect of the present application also discloses the application of the foam drainage agent composition of the present application with a CO 2 / N 2 switch in foam drainage gas production from gas wells.

[0029] The third aspect of the present application also discloses a method for drainage gas production using the foam drainage agent composition with a CO 2 / N 2 switch, which includes:

[0030] a step of adding the foam drainage agent composition to the bottom-hole liquid accumulation;

[0031] introducing CO 2 into the bottom-hole liquid accumulation to trigger the formation of a foam fluid containing a supramolecular complex by the foam drainage agent composition; and

[0032] after the foam fluid is lifted out, introducing N 2 to dissociate the contained supramolecular complex.

[0033] According to the method for gas production by liquid drainage disclosed in the present application, the addition amount of the foam drainage agent composition is 10-25 mM.

[0034] Compared with the prior art, the advantages or beneficial effects of the present application at least include:

[0035] Through the optimized design of the molecular structure of the N'-propyl betaine surfactant contained in the foam drainage agent composition disclosed in the present application, while the N'-propyl betaine surfactant has good foaming and foam stabilizing abilities and synergistic composite effects, it also endows excellent CO 2 / N 2 response performance. Thus, after being combined with Gemini quaternary ammonium salt surfactants and amino acid surfactants, it can undergo interactions through CO 2 initiation to generate a supramolecular complex rich in hydrogen bonds, endowing the foam drainage agent composition with a high association and binding force for water molecules, meeting the high-efficiency foaming and foam stabilizing requirements during foam drainage in high-temperature, high salinity, and condensate oil and gas wells. And through N 2 initiation, the generated supramolecular complex can dissociate reversely and quickly self-defoam, thus achieving an efficient and convenient foam drainage effect. Specifically, the N'-propyl betaine surfactant in the composition can undergo protonation with CO 2 to form a positively charged amidino group. This positively charged amidino group can aggregate through electrostatic interaction with the negatively charged carboxyl group of the amino acid surfactant. At the same time, the negatively charged carboxyl group of the amino acid surfactant and the quaternary ammonium group of the Gemini quaternary ammonium salt surfactant also aggregate through electrostatic interaction and form a supramolecular complex centered on the amino acid surfactant, endowing the foam drainage agent composition with more excellent foaming performance; while introducing N 2 to displace CO 2 afterwards, the positively charged amidino group of the N'-propyl betaine surfactant in the supramolecular complex undergoes deprotonation to generate charge shielding, losing the electrostatic attraction with the amino acid surfactant. The supramolecular complex becomes unstable and quickly disintegrates. The density of the surfactant adsorption layer on the foam liquid film decreases. While the foam liquid film tends to be unstable, it also loses the solution viscosity increasing effect generated by the supramolecular structure. The two effects act synergistically to accelerate the drainage and destabilization process of the foam, and the foaming and foam stabilizing properties are inhibited, effectively achieving the rapid dissociation and desorption of the foam drainage agent, realizing the pollution-free rapid dissociation of the foam drainage agent composition at a lower cost, and having better effects in foam drainage gas production for gas wells. Description of the Drawings

[0036] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments described in the present application. For those of ordinary skill in the art, other accompanying drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 It is the infrared spectrogram of the N'-propyl betaine surfactant with n = 12 provided by the embodiment of the present application;

[0038] Figure 2 It is the nuclear magnetic resonance hydrogen spectrogram of the N'-propyl betaine surfactant with n = 12 provided by the embodiment of the present application;

[0039] Figure 3 It is the repeated response curve of the foam drainage agent composition solution S6 provided by the embodiment of the present application;

[0040] Figure 4 It is the diagram of the change in the interaction energy before and after the response of the foam drainage agent composition solution S6 provided by the embodiment of the present application;

[0041] Figure 5 It is the surface tension test diagram of the foam drainage agent composition solution S6, the binary foam drainage agent composition solution S13 and the surfactant single-agent solution with different dilution multiples provided by the embodiment of the present application. Detailed implementation manners

[0042] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments described in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0043] In the following description of this specification, the term "and / or" is used to describe the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, B exists alone, and both A and B exist simultaneously. Among them, A and B can be singular or plural; the symbol " / " means "or".

[0044] In the following description of this specification, the term "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of A, B, or C", or, "at least one of A, B, and C" can represent any one of A, B, C, or A + B, or A + C, or B + C, or A + B + C, where A, B, and C can be single or multiple respectively.

[0045] In the following description of this specification, the sequence numbers do not imply the order of execution. Some or all steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, without constituting any limitation to the execution process of this embodiment.

[0046] In the following description of this specification, a numerical range should be understood to specifically disclose each intermediate value between the upper and lower limits of the range. Any stated value or intermediate value within the stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in this embodiment, and the upper and lower limits of the smaller range can be independently included or excluded from the range.

[0047] Unless otherwise specified, the technical / scientific terms used in this specification have the meanings commonly understood by those of ordinary skill in the art. Although this specification only describes preferred materials and methods, any similar or equivalent methods and materials can also be used in specific embodiments or test examples. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0048] In a first aspect, an embodiment of the present application provides a foam drainage agent composition for a CO 2 / N 2 switch. The foam drainage agent composition for the CO 2 / N 2 switch contains an N'-propyl betaine surfactant, a Gemini quaternary ammonium salt surfactant, and an amino acid surfactant;

[0049] Among them, the N'-propyl betaine surfactant has a chemical structure (1):

[0050]

[0051] n is a natural number between 11 and 16, and can be any one of 11, 12, 13, 14, 15, and 16.

[0052] Through the optimized design of the molecular structure of the N'-propyl betaine surfactant contained in the foam drainage agent composition of the embodiments of the present application, the N'-propyl betaine surfactant has good foaming and foam stabilizing abilities and synergistic composite effects, and at the same time endows excellent CO 2 / N 2 response performance. Therefore, after being combined with Gemini quaternary ammonium salt surfactant and amino acid surfactant, it can generate interactions through CO 2 initiation and form a supramolecular complex rich in hydrogen bonds, endowing the foam drainage agent composition with high association and binding force to water molecules, meeting the high-efficiency foaming and foam stabilizing requirements during foam drainage in high-temperature, high salinity and condensate gas wells, and through N 2 initiation, the generated supramolecular complex can be reversely and rapidly dissociated to self-defoam, thus achieving an efficient and convenient foam drainage effect. Specifically, the N'-propyl betaine surfactant in the composition can be protonated with CO 2 to form a positively charged amidino group. The positively charged amidino group can aggregate with the negatively charged carboxyl group of the amino acid surfactant through electrostatic interaction. At the same time, the negatively charged carboxyl group of the amino acid surfactant and the quaternary ammonium group of the Gemini quaternary ammonium salt surfactant also aggregate through electrostatic interaction and form a supramolecular complex centered on the amino acid surfactant, endowing the foam drainage agent composition with more excellent foaming performance; and after introducing N 2 to displace CO 2 , the positively charged amidino group of the N'-propyl betaine surfactant in the supramolecular complex undergoes deprotonation to generate charge shielding, losing the electrostatic attraction with the amino acid surfactant. The supramolecular complex becomes unstable and rapidly disintegrates. The density of the surfactant adsorption layer on the foam liquid film decreases. While the foam liquid film tends to be unstable, it loses the solution thickening effect generated by the supramolecular structure. The two effects work together to accelerate the drainage and destabilization process of the foam, the foaming property and foam stabilizing property are inhibited, effectively achieving the rapid dissociation and desorption of the foam drainage agent, realizing the pollution-free and rapid dissociation of the foam drainage agent composition at lower cost, and having better effect in foam drainage gas production for gas wells.

[0053] According to the foam drainage agent composition of the present disclosure, the molar ratio of the N'-propyl betaine surfactant, Gemini quaternary ammonium salt surfactant and amino acid surfactant is preferably 1:1:1. Among them, by limiting the molar ratio in the embodiments of the present application, the N'-propyl betaine surfactant, Gemini quaternary ammonium salt surfactant and amino acid surfactant can fully interact with each other and form a supramolecular complex with a stable structure, which is beneficial to improving the liquid-carrying capacity.

[0054] According to the foam drainage agent composition of the present disclosure, the Gemini quaternary ammonium salt surfactant preferably has the chemical structure (2):

[0055]

[0056] Among them, R 1 is C 11 -C 15 alkyl group.

[0057] Those skilled in the art should understand that C 11 -C 15 alkyl group refers to an alkyl chain containing 11-15 carbon atoms, and can be any one of C 11 alkyl group, C 12 alkyl group, C 13 alkyl group, C 14 alkyl group and C 15 alkyl group, and the alkyl group here includes but is not limited to straight-chain alkyl groups.

[0058] It should be noted that in the embodiments of the present application, by selecting the Gemini quaternary ammonium salt surfactant with chemical structure (2) for combined compounding, not only can good foaming and liquid-carrying effects be achieved through the excellent surface activity of the Gemini quaternary ammonium salt surfactant, but also sufficient interaction can occur with the amino acid surfactant and N'-propyl betaine surfactant contained in the composition, effectively improving the foaming and liquid-carrying ability.

[0059] The embodiments of the present application do not limit the preparation method of the Gemini quaternary ammonium salt surfactant, and it can be synthesized according to the preparation method disclosed in the literature such as ["Excellent foaming properties of anionic-zwitterionic-Gemini cationic compound surfactants for gas well deliquification: Experimental and computational investigations" Weiwei Han, Jiabao Fan et al], and the embodiments of the present application will not be described in detail.

[0060] According to the foam drainage agent composition of the present disclosure, the amino acid surfactant is preferably one of sodium lauroyl glutamate surfactant, sodium lauroyl glycinate surfactant, and sodium lauroyl lysinate surfactant. Among them, the sodium lauroyl glutamate surfactant has chemical structure (3):

[0061]

[0062] Among them, R 2 is C 11 alkyl group.

[0063] Those skilled in the art should understand that C 11 The alkyl group refers to an alkyl chain containing 11 carbon atoms, and the alkyl group here includes but is not limited to a straight-chain alkyl group.

[0064] It should be noted that in the embodiments of the present application, by selecting the amino acid surfactant for combined compounding, the carboxyl groups contained in its molecular structure can interact with N'-propyl betaine surfactants and Gemini quaternary ammonium surfactants respectively to generate a supramolecular complex with a stable structure, effectively improving the foaming and liquid-carrying ability.

[0065] According to the foam drainage agent composition of the present disclosure, the N'-propyl betaine surfactant, Gemini quaternary ammonium surfactant, and amino acid surfactant can form a supramolecular complex with chemical structure (4) in an aqueous system containing CO 2 :

[0066]

[0067] Among them, R 1 , R 2 and n all have the meanings described in the above application text and will not be elaborated here.

[0068] The embodiments of the present application also provide a preparation method of the N'-propyl betaine surfactant described in the above application text, which includes:

[0069] A step of subjecting a bromohydrin with chemical structure (5) to a sulfonation reaction with chlorosulfonic acid, and then adding a sodium salt to prepare sodium bromoalkylsulfonate;

[0070]

[0071] A step of subjecting the sodium bromoalkylsulfonate to a bromoalkylation reaction with 3-dimethylaminopropylamine to prepare an intermediate compound;

[0072]

[0073] And a step of subjecting the intermediate compound, 1,1-dimethoxy-N,N-dimethylethylamine, and ethanol to an amidine-forming reaction to prepare the target product;

[0074]

[0075] As an exemplary description, the embodiments of the present application provide a preparation method of an N'-propyl betaine surfactant with n = 12, which specifically includes:

[0076] Si: React 12-bromododecanol with chlorosulfonic acid at a molar ratio of 1:1.05. The solvent is dichloromethane (accounting for 15% of the total mass). Carry out sulfonation at 30 °C for 2 h. Age the reactants for about 30 min and then add an aqueous solution of Na 2 CO 3 with a mass fraction of 24%. Rotate and evaporate to remove the solvent to obtain a white solid. Filter the white solid with hot ethanol and rotate and evaporate the filtrate to obtain intermediate I;

[0077] Sii: Dissolve intermediate I in water, add 3-dimethylaminopropylamine (the molar ratio of intermediate I to 3-dimethylaminopropylamine is 1.2:1), heat to 80 °C, react for 12 h, then spin dry and dry under vacuum to obtain intermediate II;

[0078] Siii: React intermediate II with 1,1-dimethoxy-N,N-dimethylethylamine at a molar ratio of 1:22, add appropriate ethanol, react at 60 °C for 1 h, and then purify to obtain the N'-propyl betaine surfactant with n = 12.

[0079] To verify the successful synthesis of the N'-propyl betaine surfactant, characterize the N'-propyl betaine surfactant with n = 12 prepared by the above method by infrared spectroscopy and nuclear magnetic resonance hydrogen spectroscopy. The results are Figure 1 and Figure 2 as shown.

[0080] According to Figure 1 it is known that at 715 cm -1 is the in-plane rocking vibration absorption peak of (CH 2 ) n ; near 2916 cm -1 is the asymmetric stretching vibration peak of -CH 2 ; near 2846 cm -1 is the symmetric stretching vibration peak of symmetric -CH 2 ; at 1472 cm -1 is the absorption vibration peak of quaternary ammonium salt; near 1631 cm -1 is the stretching vibration peak of N = C; at 1276 cm -1 is the absorption peak of N-C bond; the S = O stretching vibration peak is at 1066 cm -1 .

[0081] According to Figure 2 it is known that 11H NMR (600 MHz, Methanol-d4) δ 3.51 (dt, J = 23.2, 8.4 Hz, 3H), 3.38 (t, J = 8.8 Hz, 4H) 3.14 (s, 4H), 3.08 (d, J = 7.8 Hz, 2H), 2.43 (s, 2H), 2.30 (d, J = 15.4 Hz, 4H), 1.90 - 1.65 (d, J = 8.4 Hz, 6H), 1.34 (s, 20H).

[0082] According to the characterization results described above, it shows that the target product, N'-propyl betaine surfactant with n = 12, has been successfully synthesized in the embodiments of this application.

[0083] In the second aspect, the embodiments of this application also provide the application of the foam drainage agent composition of the CO 2 / N 2 switch described above. Specifically, the CO 2 / N 2 switch foam drainage agent composition described in the embodiments of this application is used for foam drainage gas production in gas wells. Among them, considering that the CO 2 / N 2 switch foam drainage agent composition of this application has good oil resistance, salt resistance, temperature resistance, and the recyclability of the CO 2 / N 2 switch. After the foam drainage agent composition described in this application is used for foam drainage gas production in gas wells, it can not only achieve excellent foaming and liquid-carrying effects, but also avoid the related problems of foam fluid lifting to the point where defoaming agent needs to be injected later, and can also realize the recycling of the foam drainage agent composition, effectively reducing the cost of foam drainage gas production.

[0084] In the third aspect, the embodiments of this application also provide a method for drainage gas production using the foam drainage agent composition of the CO 2 / N 2 switch described above, which includes:

[0085] The step of adding the foam drainage agent composition into the bottom-hole liquid accumulation;

[0086] The step of introducing CO 2 into the bottom-hole liquid accumulation to trigger the formation of a foam fluid containing supramolecular complexes by the foam drainage agent composition; and

[0087] After the foam fluid is lifted out, the step of introducing N 2 to dissociate the contained supramolecular complexes.

[0088] Among them, the embodiments of this application do not have special limitations on the specific operations involved in the above steps, and shall be subject to the conventional construction technical requirements in the art.

[0089] According to the method of the present disclosure, the addition amount of the foam drainage agent composition is preferably 10-25 mM, and can be exemplified as 10 mM, 15 mM, 20 mM, 25 mM or any one within the range.

[0090] The technical solutions of the present application will be further described below in conjunction with specific embodiments.

[0091] Example 1

[0092] This example provides a foam drainage agent composition solution S1, which contains:

[0093] At room temperature, an N'-propyl betaine surfactant (n = 11), a Gemini quaternary ammonium salt surfactant (R 1 = C 11 normal alkyl), and a sodium lauroyl glycinate surfactant are dissolved in 200 mL of clear water according to a molar concentration ratio of 1:1:1 and ultrasonically treated to obtain a 15 mM foam drainage agent composition solution S1.

[0094] Example 2

[0095] This example provides a foam drainage agent composition solution S2, which contains:

[0096] At room temperature, an N'-propyl betaine surfactant (n = 12), a Gemini quaternary ammonium salt surfactant (R 1 = C 13 normal alkyl), and a sodium lauroyl glycinate surfactant are dissolved in 200 mL of clear water according to a molar concentration ratio of 1:1:1 and ultrasonically treated to obtain a 15 mM foam drainage agent composition solution S2.

[0097] Example 3

[0098] This example provides a foam drainage agent composition solution S3, which contains:

[0099] At room temperature, an N'-propyl betaine surfactant (n = 14), a Gemini quaternary ammonium salt surfactant (R 1 = C 15 normal alkyl), and a sodium lauroyl glycinate surfactant are dissolved in 200 mL of clear water according to a molar concentration ratio of 1:1:1 and ultrasonically treated to obtain a 15 mM foam drainage agent composition solution S3.

[0100] Example 4

[0101] This example provides a foam drainage agent composition solution S4, which contains:

[0102] At room temperature, an N'-propyl betaine surfactant (n = 15), a Gemini quaternary ammonium salt surfactant (R 1 = C13 The n-alkyl and sodium lauroyl glutamate surfactants were dissolved in 200 mL of clear water at a molar concentration ratio of 1:1:1 and ultrasonically treated to obtain a 15 mM foam drainage agent composition solution S4.

[0103] Example 5

[0104] This example provides a foam drainage agent composition solution S5, which contains:

[0105] At room temperature, the N'-propyl betaine surfactant (n = 11), Gemini quaternary ammonium salt surfactant (R 1 = C 11 n-alkyl) and sodium lauroyl glutamate surfactant were dissolved in 200 mL of clear water at a molar concentration ratio of 1:1:1 and ultrasonically treated to obtain a 15 mM foam drainage agent composition solution S5.

[0106] Example 6

[0107] This example provides a foam drainage agent composition solution S6, which contains:

[0108] At room temperature, the N'-propyl betaine surfactant (n = 12), Gemini quaternary ammonium salt surfactant (R 1 = C 15 n-alkyl) and sodium lauroyl glutamate surfactant were dissolved in 200 mL of clear water at a molar concentration ratio of 1:1:1 and ultrasonically treated to obtain a 15 mM foam drainage agent composition solution S6.

[0109] Example 7

[0110] This example provides a foam drainage agent composition solution S7, which contains:

[0111] At room temperature, the N'-propyl betaine surfactant (n = 11), Gemini quaternary ammonium salt surfactant (R 1 = C 11 n-alkyl) and sodium lauroyl lysine surfactant were dissolved in 200 mL of clear water at a molar concentration ratio of 1:1:1 and ultrasonically treated to obtain a 15 mM foam drainage agent composition solution S7.

[0112] Example 8

[0113] This example provides a foam drainage agent composition solution S8, which contains:

[0114] At room temperature, the N'-propyl betaine surfactant (n = 12), Gemini quaternary ammonium salt surfactant (R 1 = C 13The N'-propyl betaine surfactant (n = 15), Gemini quaternary ammonium salt surfactant (R = C normal alkyl), and lauroyl lysine surfactant were dissolved in 200 mL of clear water at a molar concentration ratio of 1:1:1 and ultrasonically treated to obtain a 15 mM foam drainage agent composition solution S8.

[0115] Example 9

[0116] This example provides a foam drainage agent composition solution S9, which contains:

[0117] At room temperature, the N'-propyl betaine surfactant (n = 15), Gemini quaternary ammonium salt surfactant (R 1 = C 15 normal alkyl), and lauroyl lysine surfactant were dissolved in 200 mL of clear water at a molar concentration ratio of 1:1:1 and ultrasonically treated to obtain a 15 mM foam drainage agent composition solution S8.

[0118] To verify the actual performance of the foam drainage agent composition prepared in this application, the foam properties of the foam drainage agent composition solutions prepared in Examples 1-9 were tested according to SY / T5350-2009 "Evaluation Procedure for Foaming Agents for Drilling Fluids" and SY / T 7494-2020 "Experimental Evaluation Method for Foaming Agents for Oil and Gas Fields", respectively.

[0119] 1. The test process of the foaming performance is as follows:

[0120] For the foaming volume and half-life, the stirring method was used. 100 mL of the foam drainage agent composition solutions S1-S9 were respectively taken and placed in a high-speed blender for stirring for 3 minutes (rotation speed: 7000 revolutions per minute), and the foam generated by each foam drainage agent composition solution was poured into a graduated cylinder to test the maximum foaming volume and half-life (the time taken to precipitate 50 mL of the solution). Among them, the salinity of the clear water was 0 mg / L, and the room temperature was 25 °C.

[0121] 2. The test process of the liquid-carrying performance is as follows:

[0122] Using a foam liquid-carrying evaluation device, nitrogen was passed through a glass sand core to be dispersed into microbubbles and introduced into a glass column. The gas flow rate was controlled at 400 mL / minute, and the generated foam carried the liquid out of the pipe column. The amount of liquid carried out by the foam drainage agent composition solution under different conditions after 9 minutes of aeration was tested.

[0123] 3. Test results

[0124] Table 1: Test results of the foam properties of the foam drainage agent composition solutions S1-S9.

[0125] Foam drainage agent composition solution Foaming volume, mL Half-life, min Liquid-carrying rate, % Foam drainage agent composition solution S1 425 23 27.9 Foam drainage agent composition solution S2 410 24 28.7 Foam drainage agent composition solution S3 405 26 25.7 Foam drainage agent composition solution S4 425 30 29.6 Foam drainage agent composition solution S5 445 26 30.1 Foam drainage agent composition solution S6 435 27 34.1 Foam drainage agent composition solution S7 435 24 29.6 Foam drainage agent composition solution S8 430 26 32.7 Foam drainage agent composition solution S9 420 27 30.5

[0126] According to Table 1, the alkyl chain lengths of the N'-propyl betaine surfactant and the Gemini quaternary ammonium salt surfactant contained in the foam drainage agent composition both affect its foam properties. Specifically, when the amino acid surfactant is sodium lauroyl glycinate, the foaming volume of the foam drainage agent composition decreases as the alkyl chain lengths of the N'-propyl betaine surfactant and the Gemini quaternary ammonium salt surfactant increase, but the half-life increases as the alkyl chain lengths of the N'-propyl betaine surfactant and the Gemini quaternary ammonium salt surfactant increase, and the liquid-carrying performance is the highest when the alkyl chain lengths of the N'-propyl betaine surfactant and the Gemini quaternary ammonium salt surfactant are moderate; when the amino acid surfactant is sodium lauroyl glutamate, the foaming volume of the foam drainage agent composition decreases as the alkyl chain lengths of the N'-propyl betaine surfactant and the Gemini quaternary ammonium salt surfactant increase, but the half-life increases as the alkyl chain lengths of the N'-propyl betaine surfactant and the Gemini quaternary ammonium salt surfactant increase, and the liquid-carrying performance is the highest when the alkyl chain lengths of the N'-propyl betaine surfactant and the Gemini quaternary ammonium salt surfactant are moderate; when the amino acid surfactant is sodium lauroyl lysinate, the foaming volume of the foam drainage agent composition decreases as the alkyl chain lengths of the N'-propyl betaine surfactant and the Gemini quaternary ammonium salt surfactant increase, but the half-life increases as the alkyl chain lengths of the N'-propyl betaine surfactant and the Gemini quaternary ammonium salt surfactant increase, and the liquid-carrying performance is the highest when the alkyl chain lengths of the N'-propyl betaine surfactant and the Gemini quaternary ammonium salt surfactant are moderate. Therefore, the present application preferably uses a combination (S6) of an N'-propyl betaine surfactant with n = 12, a Gemini quaternary ammonium salt surfactant with R 1 = C 15 -alkyl Gemini quaternary ammonium salt surfactant and sodium lauroyl glutamate surfactant.

[0127] To illustrate the oil resistance, salt resistance, and temperature resistance effects of the foam drainage agent composition described in the present application, a test experiment was conducted using the composition components of the foam drainage agent composition solution S6 as test samples in this article.

[0128] Experimental Example 1

[0129] At room temperature, an N'-propyl betaine surfactant (n = 12), a Gemini quaternary ammonium salt surfactant (R 1 = C 15 -alkyl) and sodium lauroyl glutamate surfactant were dissolved in 200 mL of a brine sample with a salinity of 270,000 mg / L (molar ratio of NaCl:CaCl 2 is 4:1) according to a molar concentration ratio of 1:1:1 and ultrasonically treated to obtain a 15 mM mineralized solution S10 of the foam drainage agent composition, and then its foam properties were tested.

[0130] Experimental Example 2

[0131] At room temperature, an N'-propyl betaine surfactant (n = 12), a Gemini quaternary ammonium salt surfactant (R 1 = C 15 n-alkyl) and sodium lauroyl glutamate surfactant were dissolved in 200 mL of an oil-water mixture containing 60% by volume of condensate oil in a molar concentration ratio of 1:1:1 and sonicated to obtain an oil-water solution S11 of a foam drainage agent composition with a concentration of 15 mM, and then its foam properties were tested.

[0132] Experimental Example 3

[0133] The liquid-carrying performance of the foam drainage agent composition solution S6 was tested at 90°C (Note: Due to the limitations of the test standard SY / T5350-2009, the foam volume and half-life of the foam drainage agent composition under the condition of 90°C have not been tested).

[0134] Table 2: Test results of the foam properties of Examples 1-3

[0135] Experimental example Foaming volume, mL Half-life, min Liquid-carrying rate, % Experimental example 1 435 25 32.8 Experimental example 2 430 26 33.2 Experimental example 3 / / 86.6

[0136] As can be seen from Table 2, the foam properties obtained from the tests in Experimental Examples 1-3 are close to those in Example 6, indicating that the foam drainage agent composition solution of the examples of the present application has excellent anti-mineralization, anti-condensate oil, and good temperature resistance effects.

[0137] Secondly, the present application tested the change diagram of the interaction energy before and after the response and the repeated response curve of the foam drainage agent composition solution S6.

[0138] The test method was as follows: The response performance was tested using a foam analyzer. The test object was the foam drainage agent composition solution S6. N 2 was injected into the solution at a flow rate of 0.7 L / min. For the responsive foaming process, CO 2 was injected into the foaming solution at a flow rate of 0.3 L / min. After a certain time, N 2 was introduced at a flow rate of 0.7 L / min, and the above foaming process was repeated to study the periodic response characteristics of the system. The test results are as Figure 3 shown; at the same time, to further verify the above response characteristics, the Atom based method was used to calculate the intermolecular interaction before and after the response, and the results are as Figure 4 shown.

[0139] According to Figure 3 it can be seen that in the experiment of alternately introducing CO 2 (used to initiate foaming) and N 2 (used to stimulate defoaming) into the foam drainage agent composition solution, when introducing CO2 When, the N'-propyl betaine N,N-dimethylacetamidine (n = 12) is protonated and forms a water-soluble bicarbonate amidine surfactant, and there will be a rapid rising period of the foam height; when introducing N 2 When, the N'-propyl betaine N,N-dimethylacetamidine molecule is deprotonated. Although the foaming volume still continues to rise briefly, the interaction gradually disappears, and the water-soluble bicarbonate amidine is converted back to the original N'-propyl betaine N,N-dimethylacetamidine. Subsequently, the foam height will rapidly decrease, achieving a defoaming effect, and the response period is on average 2200 s. The above phenomena indicate that the composite system of N'-propyl betaine N,N-dimethylacetamidine surfactant (n = 12), sodium lauroyl glutamate surfactant and Gemini quaternary ammonium salt surfactant (C15) has good CO 2 / N 2 reversible response performance;

[0140] According to Figure 4 it can be known that after the N'-propyl betaine N,N-dimethylacetamidine surfactant (n = 12), sodium lauroyl glutamate surfactant and Gemini quaternary ammonium salt surfactant (C15) composite foam system is protonated, the molecules that were originally all located at the gas-liquid interface attract each other due to electrostatic interaction to form a supramolecular system, greatly improving the foaming and foam-stabilizing effects, and effectively realizing the CO 2 / N 2 response characteristics.

[0141] Finally, the present application tested the surface tension of the foam drainage agent composition solution S6 with different dilution multiples.

[0142] The test method is as follows: at room temperature, test the change of the surface tension of the foam drainage agent composition solution at different concentrations (0.0002 - 13.5 mmol / L). Among them, the test objects include the foam drainage agent composition solution S6 [i.e., N'-propyl betaine N,N-dimethylacetamidine surfactant (n = 12), sodium lauroyl glutamate surfactant and Gemini quaternary ammonium salt surfactant (C15) prepared according to the molar concentration ratio of 1:1:1], the binary foam drainage agent composition solution S13 [i.e., N'-propyl betaine N,N-dimethylacetamidine surfactant (n = 12), sodium lauroyl glutamate surfactant prepared according to the molar concentration ratio of 1:1], the single-agent solution of N'-propyl betaine N,N-dimethylacetamidine surfactant (n = 12), the single-agent solution of sodium lauroyl glutamate surfactant, and the single-agent solution of Gemini quaternary ammonium salt surfactant (C15). The test results are Figure 5 as shown.

[0143] According to Figure 5It can be seen that the equilibrium surface tension of the foam drainage agent composition solution S6 fluctuates around 25.4 mN / m; the equilibrium surface tension of the binary foam drainage agent composition solution S13 fluctuates around 26.4 mN / m; the equilibrium surface tensions of the remaining 3 surfactant single-agent solutions fluctuate around 26.4 - 27.0 mN / m. Moreover, the critical micelle concentration of the foam drainage agent composition solution S6 is lower than that of any surfactant single-agent and the binary foam drainage agent composition solution S13, indicating that the compounding ratio corresponding to the foam drainage agent composition solution S6 shows superiority in reducing the surface tension.

[0144] According to the above tests, it can be known that the foam drainage agent composition provided in the embodiments of the present application has excellent foaming, foam stabilizing and liquid-carrying capabilities in a clear water system. Moreover, the decline in the foaming and foam stabilizing capabilities of Comparative Example 1 and Comparative Example 2 is very small, proving that the foam drainage agent composition provided in the embodiments of the present application has good salt tolerance and oil tolerance properties.

[0145] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other, and the key points of each embodiment are the differences from other embodiments.

[0146] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present application.

Claims

1. A foaming agent composition for a CO2 / N2 switch, characterized in that: Contains N'-propyl betaine surfactant, Gemini quaternary ammonium salt surfactant and amino acid surfactant; The N'-propyl betaine surfactant has a chemical structure (1): n is a natural number between 11 and 16.

2. The foaming agent composition according to claim 1, characterized in that The molar ratio of the N'-propyl betaine surfactant, the Gemini quaternary ammonium salt surfactant and the amino acid surfactant is 1:1:

1.

3. The foaming agent composition according to claim 1, characterized in that The Gemini quaternary ammonium salt surfactant has a chemical structure (2): Where R1 is C 11 -C 15 alkyl.

4. The foaming agent composition according to claim 1, characterized in that The amino acid surfactant is one of a sodium lauroyl glutamate surfactant, a sodium lauroyl glycinate surfactant, and a sodium lauroyl lysine surfactant.

5. The foaming agent composition according to claim 4, characterized in that: The sodium lauroyl glutamate surfactant has a chemical structure (3): Where R2 is C 11 alkyl.

6. The foaming agent composition according to claim 5, characterized in that The N'-propyl betaine surfactant, Gemini quaternary ammonium salt surfactant and amino acid surfactant can form a supramolecular complex with a chemical structure (4) in an aqueous system containing CO2:

7. The foaming agent composition according to any one of claims 1 to 6, characterized in that: The preparation method of the N'-propyl betaine surfactant comprises: The step of allowing bromohydrin to undergo sulfonation reaction with chlorosulfonic acid and then adding sodium salt to prepare sodium brominated alkylsulfonate; The sodium brominated alkyl sulfonate is reacted with 3-dimethylaminopropylamine to produce an intermediate compound by bromoalkylation reaction Steps; and, a step of subjecting the intermediate compound, 1,1-dimethoxy-N,N-dimethylethylamine and ethanol to an amidine reaction to prepare a target product; 8. Use of the CO2 / N2 switch foaming agent composition according to any one of claims 1 to 7 in gas well foam drainage and gas production.

9. A method for draining liquid and collecting gas using the foaming agent composition of the CO2 / N2 switch according to any one of claims 1 to 7, characterized in that: Include: The step of adding the foaming agent composition into the bottom well fluid; A step of introducing CO2 into the bottom hole fluid to induce the foaming agent composition to form a foam fluid containing a supramolecular complex; And after the foam fluid is discharged, N2 is introduced to dissociate the supramolecular complex contained therein.

10. The method according to claim 9, characterized in that The added amount of the foaming agent composition is 10-25mM.

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