Nano foam scrubbing agent suitable for environments with various temperatures and mineralization degrees as well as preparation method and application of nano foam scrubbing agent

Abstract

The invention provides a nano foam scrubbing agent suitable for environments with various temperatures and mineralization degrees as well as a preparation method and application of the nano foam scrubbing agent. The nano foam scrubbing agent comprises an anionic surfactant, a nonionic surfactant, a zwitterionic surfactant, foam stabilizing particles and a solvent, the total mass concentration of the anionic surfactant, the nonionic surfactant and the zwitterionic surfactant in the nano foam scrubbing agent is 0.1-1.0 wt%, and the mass concentration of the foam stabilizing particles is 0.1-0.5 wt%; the mass ratio of the anionic surfactant to the nonionic surfactant to the zwitterionic surfactant is (10-30): (15-20): (15-25). The foam scrubbing agent disclosed by the invention has relatively good foaming, foam stabilizing and liquid carrying capacities at 35-95 DEG C in a mineralization degree range of 10000-50000 mg / L, has very good salt resistance and calcium and magnesium ion resistance, and can adapt to environments with various temperatures and different mineralization degrees.

Description

Technical Field

[0001] The invention belongs to the technical field of foaming agent preparation, and specifically relates to a nano foaming agent suitable for various temperature and mineralization environments, and a preparation method and application thereof. Background Art

[0002] In the field of natural gas exploration, foam drainage and gas production technology has been widely used due to its ability to efficiently separate gas and liquid. With the development of unconventional natural gas resources such as shale gas, complex mineralized environments have put forward higher requirements on the performance of foaming agents. Especially under variable temperature and mineralization conditions, traditional foaming agents are often difficult to meet the comprehensive performance requirements of temperature resistance and salt resistance at the same time. Therefore, the development of new multi-temperature adaptive nano foaming agents to adapt to drainage and gas production operations in complex mineralized environments has become a hot topic of current research. Specifically, the foaming performance, foam stabilization performance and liquid carrying performance of the foaming agent are the key factors that determine the effect of foam drainage and gas production.

[0003] In recent years, research has focused on improving the environmental adaptability of foaming agents through chemical modification and the introduction of nanotechnology. For example, Chinese patent document CN117625165A discloses a high-temperature foaming agent for drainage and gas production, which contains cellulose, dodecylamine, aminosulfonic acid, and methanol, but has poor salt tolerance. Chinese patent document CN115785933A discloses a salt-inhibiting foaming agent for high-mineralization natural gas well development, the components of which are the following components by weight: 30-40 parts of sulfonated AEO3, 10-20 parts of OP-10, 10-20 parts of maleic anhydride (MA) / sodium p-styrene sulfonate (SSS) binary polymer, 5-10 parts of polyaspartic acid, 5-10 parts of ethylene glycol and 3-5 parts of sodium polyoxyethylene fatty alcohol ether sulfate. Within the mineralization range of 200-350g / L, the foaming power and liquid carrying rate have no obvious downward trend, but as the mineralization increases, the foaming power and liquid carrying rate show a significant downward trend, or even completely fail.

[0004] At present, how to effectively cope with the complex and changeable temperature and salinity environment has become one of the key challenges to improve recovery efficiency. In particular, under extreme temperature and high salinity conditions, traditional foaming agents are often difficult to stably exist or exert their effects, resulting in increased development costs of oil and gas fields and reduced recovery rates. Therefore, it is necessary to develop a nano foaming agent that can adapt to a variety of temperature and salinity environments, and through material innovation and process optimization, to achieve effective development of oil and gas fields in complex environments. To this end, the present invention is proposed. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a nano foaming agent suitable for various temperature and salinity environments, and a preparation method and application thereof. The foaming agent of the present invention has good foaming, foam stabilization and liquid carrying capabilities within a temperature range of 35-95°C and a salinity range of 10000mg / L-50000mg / L, and has good compatibility with formation water, and has good salt resistance and calcium and magnesium ion resistance. It can adapt to various temperatures and different salinity environments, and solves the problem that the existing foaming agents have poor performance at different temperatures and salinities.

[0006] The technical solution of the present invention is as follows:

[0007] A nano foaming agent suitable for various temperature and mineralization environments, comprising anionic surfactants, nonionic surfactants, zwitterionic surfactants, foam-stabilizing particles and solvents; the total mass concentration of the anionic surfactants, nonionic surfactants and zwitterionic surfactants in the nano foaming agent is 0.1-1.0wt%, and the mass concentration of the foam-stabilizing particles is 0.1-0.5wt%; the mass ratio of the anionic surfactants, nonionic surfactants and zwitterionic surfactants is 10-30:15-20:15-25.

[0008] Preferably according to the present invention, the total mass concentration of the anionic surfactant, the nonionic surfactant and the zwitterionic surfactant in the nano foaming agent is 0.5-0.9wt%.

[0009] Preferably according to the present invention, the anionic surfactant is alkylphenol polyoxyethylene ether phosphate (APE-4P) and / or sodium cocoyl isethionate (CAS No.: 61789-32-0).

[0010] Preferably according to the present invention, the nonionic surfactant is fatty alcohol polyoxyethylene ether, further preferably fatty alcohol polyoxyethylene ether 3 (AEO-3), fatty alcohol polyoxyethylene ether 5 (AEO-5), fatty alcohol polyoxyethylene ether 7 (AEO-7), fatty alcohol polyoxyethylene ether 9 (AEO-9) or a combination of two or more thereof, more preferably fatty alcohol polyoxyethylene ether 9 (AEO-9).

[0011] Preferably according to the present invention, the zwitterionic surfactant is one or a combination of two or more of cocoylpropyl sulfobetaine (CHSB, CAS No. 68139-30-0), lauramide propyl amine oxide (LAO-30, CAS No. 61792-31-2), cocoyl propyl betaine (LAB-35, CAS No. 61789-40-0), and cetearyl dimethyl hydroxypropyl sulfobetaine (HSB1618), and is further preferably lauramide propyl amine oxide (LAO-30).

[0012] Preferably according to the present invention, the mass ratio of the anionic surfactant, the nonionic surfactant and the zwitterionic surfactant in the nano foaming agent is 1:1:1.

[0013] Preferably according to the present invention, the foam stabilizing particles are one of nano-silicon dioxide, carbon nanofiber CNF, and titanium dioxide nanoparticles, and nano-silicon dioxide is further preferred; the particle size of the nano-silicon dioxide is 80-100nm; the particle size of the titanium dioxide nanoparticles is 80-100nm; the diameter of the carbon nanofiber CNF is 10-500nm, and the length is 0.5-100μm.

[0014] Preferably according to the present invention, the solvent is one or a combination of two or more of water, methanol and ethanol; in the present invention, no special requirements are put forward for the water quality, the water can be deionized water or water containing inorganic minerals, the water containing inorganic minerals can be tap water, gas well formation water, gas well injection water or mineralized water, and the mineralization of the mineralized water is 10000mg / L-50000mg / L.

[0015] According to the present invention, the preparation method of the nano foaming agent applicable to various temperature and mineralization environments comprises the following steps:

[0016] At room temperature, anionic surfactants, nonionic surfactants and zwitterionic surfactants are added to a solvent to obtain a mixed solution, and then foam-stabilizing particles are added to the mixed solution and dispersed uniformly by ultrasonication to obtain the product.

[0017] According to the present invention, the above-mentioned nano foaming agent suitable for various temperature and mineralization environments is used in gas well drainage and gas production, the temperature of the gas well is 35-95°C, such as 35°C, 50°C, 65°C, 80°C, 95°C, etc.; the mineralization of the gas well is 10000mg / L-50000mg / L, such as 10000mg / L, 20000mg / L, 30000mg / L, 40000mg / L, 50000mg / L, etc.

[0018] The technical features and beneficial effects of the present invention are as follows:

[0019] 1. The foaming agent of the present invention is compounded with foam-stabilizing particles and anionic surfactants, nonionic surfactants and amphoteric surfactants. The heat-resistant and salt-resistant drainage and gas recovery foaming agent of the present invention uses a specific zwitterionic surfactant, which has good foaming and foam stabilizing capabilities, can produce rich, thick and delicate foam, and has a significant thickening effect on anionic surfactants in appropriate proportions. The anionic surfactant used is easily soluble in water, has good foaming ability, and has good salt resistance. It has good compatibility with zwitterionic and nonionic surfactants and is insensitive to alkali and hard water. The nonionic surfactant used has uniform foaming performance, good defoaming performance and outstanding low-temperature washing performance. The three have outstanding synergistic effects after mixing, which can greatly reduce the use and consumption of auxiliary agents and achieve good cost performance; at the same time, it enhances the liquid carrying capacity and foam stabilizing performance of the foam. The addition of nano-microbubble particles can effectively increase the viscosity of the foam system, while forming a dense particle film, inhibiting the aggregation and disproportionation of bubbles, thereby enhancing the stability of the foam; if the types of anionic surfactants, nonionic surfactants, and zwitterionic surfactants in the present invention are changed, especially the type of anionic surfactants, the performance of the resulting foaming agent is poor.

[0020] 2. The foam-stabilizing particles of the present invention have a significant improvement on the stability of the foam. The synergistic effect of the various components makes the foam-discharging agent have stronger foaming ability, better foam-stabilizing effect and stronger liquid-carrying capacity. However, if the content of the foam-stabilizing particles is too high or too low, the performance of the foam-discharging agent will be reduced. The product can maintain stable foaming in the temperature range of 35-95°C and has good salt resistance.

[0021] 3. The foaming agent prepared by the present invention can adapt to high-mineralization water layers, has strong foaming properties, high liquid carrying rate, and high salt inhibition rate, and can adapt to high-mineralization formation water such as Yanchang gas well to a great extent, effectively solving the technical problems of foaming and low liquid carrying performance of the foaming agent in high-mineralization formation water and pipeline blockage caused by salting out; the present invention is suitable for wellbore drainage of condensate gas wells in exploitation, can stably foam in the temperature range of 35-95°C, has good salt resistance, and can resist the interference of mineralization 10000mg / L-50000mg / L. The foaming agent of the present invention has simple composition, low price, strong foaming ability, good foam stability, can resist the underground environment of high mineralization and high temperature, and can meet the demand for foam drainage of natural gas underground. DETAILED DESCRIPTION

[0022] The technical solution will be described clearly and completely below in conjunction with the embodiments of the present invention. However, this should not be understood as the scope of the above-mentioned subject matter of the present invention being limited to the following embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0023] Meanwhile, the raw materials used in the examples are conventional raw materials and can be obtained commercially; the methods described are all prior art unless otherwise specified.

[0024] In the embodiments, comparative examples and test examples, the composition of the simulated mineralized water used is shown in Tables 1-5 below.

[0025] Table 1 Total mineralization 10000 mg / L

[0026] Reagents <![CDATA[CaCl2]]> <![CDATA[MgCl2]]> <![CDATA[NaSO4]]> NaCl Concentration mg / L 0.865g 0.585g 2.635g 5.915g

[0027] Table 2 Total mineralization 20000 mg / L

[0028] Reagents <![CDATA[CaCl2]]> <![CDATA[MgCl2]]> <![CDATA[NaSO4]]> NaCl Concentration mg / L 1.73g 1.17g 5.27g 11.83g

[0029] Table 3 Total mineralization 30000 mg / L

[0030] Reagents <![CDATA[CaCl2]]> <![CDATA[MgCl2]]> <![CDATA[NaSO4]]> NaCl Concentration mg / L 2.595g 1.755g 7.905g 17.745g

[0031] Table 4 Total mineralization 40000 mg / L

[0032] Reagents <![CDATA[CaCl2]]> <![CDATA[MgCl2]]> <![CDATA[NaSO4]]> NaCl Concentration mg / L 3.46g 2.34g 10.54g 23.66g

[0033] Table 5 Total mineralization 50000 mg / L

[0034] Reagents <![CDATA[CaCl2]]> <![CDATA[MgCl2]]> <![CDATA[NaSO4]]> NaCl Concentration mg / L 4.325g 2.925g 13.175g 29.575g

[0035] Example 1

[0036] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments comprises the following steps:

[0037] At room temperature, sodium cocoyl isethionate, fatty alcohol polyoxyethylene ether 9 (AEO-9), and lauramide propyl amine oxide (LAO-30) are added to water in a mass ratio of 1:1:1 to obtain a mixed solution, nano-silicon dioxide (particle size of 80-100 nm) is added to the mixed solution, and ultrasonic treatment is performed and mixed uniformly to obtain a nano-foaming agent, in which the total mass concentration of sodium cocoyl isethionate, fatty alcohol polyoxyethylene ether 9 (AEO-9), and lauramide propyl amine oxide (LAO-30) is 0.1wt%, and the mass concentration of nano-silicon dioxide is 0.2wt%. The obtained nano-foaming agent is recorded as GL-1.

[0038] Example 2

[0039] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 1, except that the total mass concentration of sodium cocoyl isethionate, fatty alcohol polyoxyethylene ether 9 (AEO-9), and lauramide propylamine oxide (LAO-30) in the nano foaming agent is 0.3wt%, and the obtained nano foaming agent is recorded as GL-2.

[0040] Example 3

[0041] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 1, except that the total mass concentration of sodium cocoyl isethionate, fatty alcohol polyoxyethylene ether 9 (AEO-9), and lauramide propylamine oxide (LAO-30) in the nano foaming agent is 0.5wt%, and the obtained nano foaming agent is recorded as GL-3.

[0042] Example 4

[0043] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 1, except that the total mass concentration of sodium cocoyl isethionate, fatty alcohol polyoxyethylene ether 9 (AEO-9), and lauramide propylamine oxide (LAO-30) in the nano foaming agent is 0.7wt%, and the obtained nano foaming agent is recorded as GL-4.

[0044] Example 5

[0045] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 1, except that the total mass concentration of sodium cocoyl isethionate, fatty alcohol polyoxyethylene ether 9 (AEO-9), and lauramide propylamine oxide (LAO-30) in the nano foaming agent is 0.9wt%, and the obtained nano foaming agent is recorded as GL-5.

[0046] Example 6

[0047] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 1, except that the total mass concentration of sodium cocoyl isethionate, fatty alcohol polyoxyethylene ether 9 (AEO-9), and lauramide propylamine oxide (LAO-30) in the nano foaming agent is 1wt%, and the obtained nano foaming agent is recorded as GL-6.

[0048] Example 7

[0049] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 5, except that an equal mass of alkylphenol polyoxyethylene ether phosphate (APE-4P) is used instead of sodium cocoyl isethionate, and water is replaced with simulated mineralized water with a mineralization of 50,000 mg / L. The resulting nano foaming agent is recorded as GL-7.

[0050] Example 8

[0051] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 1, except that water is replaced by simulated mineralized water with mineralizations of 10000 mg / L, 20000 mg / L, 30000 mg / L, 40000 mg / L, and 50000 mg / L, respectively. The obtained nano foaming agents are recorded as GL-1-10000, GL-1-20000, GL-1-30000, GL-1-40000, and GL-1-50000.

[0052] Example 9

[0053] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 2, except that water is replaced by simulated mineralized water with mineralizations of 10000 mg / L, 20000 mg / L, 30000 mg / L, 40000 mg / L, and 50000 mg / L, respectively. The resulting nano foaming agents are recorded as GL-2-10000, GL-2-20000, GL-2-30000, GL-2-40000, and GL-2-50000.

[0054] Example 10

[0055] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 3, except that water is replaced by simulated mineralized water with mineralizations of 10000 mg / L, 20000 mg / L, 30000 mg / L, 40000 mg / L, and 50000 mg / L, respectively. The resulting nano foaming agents are recorded as GL-3-10000, GL-3-20000, GL-3-30000, GL-3-40000, and GL-3-50000.

[0056] Embodiment 11

[0057] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 4, except that water is replaced by simulated mineralized water with mineralizations of 10000 mg / L, 20000 mg / L, 30000 mg / L, 40000 mg / L, and 50000 mg / L, respectively. The resulting nano foaming agents are recorded as GL-4-10000, GL-4-20000, GL-4-30000, GL-4-40000, and GL-4-50000.

[0058] Example 12

[0059] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 5, except that water is replaced by simulated mineralized water with mineralizations of 10000 mg / L, 20000 mg / L, 30000 mg / L, 40000 mg / L, and 50000 mg / L, respectively. The resulting nano foaming agents are recorded as GL-5-10000, GL-5-20000, GL-5-30000, GL-5-40000, and GL-5-50000.

[0060] Example 13

[0061] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 6, except that water is replaced by simulated mineralized water with mineralizations of 10000 mg / L, 20000 mg / L, 30000 mg / L, 40000 mg / L, and 50000 mg / L, respectively. The resulting nano foaming agents are recorded as GL-6-10000, GL-6-20000, GL-6-30000, GL-6-40000, and GL-6-50000.

[0062] Embodiment 14

[0063] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 7, except that the simulated mineral water has a mineralization degree of 10000 mg / L, and the obtained nano foaming agent is recorded as GL-7-10000.

[0064] Comparative Example 1

[0065] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 1, except that: no anionic surfactant sodium cocoyl isethionate is added, fatty alcohol polyoxyethylene ether 9 (AEO-9) and lauramide propyl amine oxide (LAO-30) are added to simulated mineralized water with a mineralization degree of 50000 mg / L in a mass ratio of 1:1, and the total mass concentration of fatty alcohol polyoxyethylene ether 9 (AEO-9) and lauramide propyl amine oxide (LAO-30) in the nano foaming agent is 0.1wt%.

[0066] Comparative Example 2

[0067] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 2, except that the water used is simulated mineralized water with a mineralization of 50,000 mg / L, and no nano-silicon dioxide is added.

[0068] Comparative Example 3

[0069] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 3, except that sodium cocoyl isethionate, fatty alcohol polyoxyethylene ether 9 (AEO9), and lauryl amide propyl amine oxide (LAO-30) are added to simulated mineralized water with a mineralization degree of 50,000 mg / L in a mass ratio of 1:2:3.

[0070] Comparative Example 4

[0071] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 5, except that sodium lauryl ether sulfate (SLES-2EO) is used instead of sodium coconut oil isethionate.

[0072] Comparative Example 5

[0073] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 5, except that sodium dodecyl sulfate (SDS) is used instead of sodium coconut oil isethionate.

[0074] Comparative Example 6

[0075] A method for preparing a nano foaming agent suitable for various temperature and mineralization environments is as described in Example 5, except that sodium secondary alkyl sulfonate (SAS-60) is used instead of sodium coconut oil isethionate.

[0076] Test example

[0077] The evaluation of the foaming agent mainly includes two aspects: one is to evaluate and measure the foaming power and foam stabilization ability of the foaming agent, and the other is to measure the liquid carrying capacity of the foaming agent. According to SY / T6465-2000 "Evaluation Method of Foaming Agent for Foam Drainage and Gas Collection", the foam performance of the foaming agent was tested.

[0078] Evaluation of foaming power and foam stabilization performance: Waring-Blender method was used. 100 mL of the prepared nano foaming agent was taken and stirred in a high-speed blender at 7000 r / min for 2 minutes, and then the foam was poured into a measuring cylinder to test the maximum foaming volume and half-life (i.e. the time taken to precipitate 50 mL of solution).

[0079] Determination of liquid carrying capacity: The liquid carrying performance of the foaming agent is tested in accordance with SY / T7494-2020 "Experimental Evaluation Method for Foaming Agents for Oil and Gas Fields". The specific test process is as follows: Using a foam liquid carrying evaluation device, nitrogen is dispersed into microbubbles through a glass sand core and introduced into a glass column. The gas flow rate is controlled at 0.4L / min. The generated foam carries the liquid out of the column. When the foaming agent is tested and nitrogen is introduced for 9 minutes, the amount of liquid carried out with the foam is used as a measure of the liquid carrying capacity of the foaming agent.

[0080] Test conditions: no condensate oil and temperatures of 35°C, 50°C, 65°C, 80°C, and 95°C.

[0081] (I) Performance evaluation of foaming agent prepared in clean water system

[0082] 1. Foaming ability and foam stability

[0083] The foaming and foam stabilization test results of the foaming agents GL-1 to GL-6 prepared in Examples 1 to 6 of the present invention are shown in Table 6.

[0084] Table 6 Performance of foaming agent at different ratios and concentrations (room temperature)

[0085] Name of foaming agent Foam volume / mL Half-life / s Foam comprehensive index / mL s GL-1 355 224 59640 GL-2 364 298 81354 GL-3 410 307 94402.5 GL-4 430 382 123195 GL-5 457 435 149096.25 GL-6 442 400 132600 Comparative Example 4 405 379 115121.25 Comparative Example 5 421 396 123037 Comparative Example 6 400 413 123900

[0086] According to Table 6, the foaming agents of Examples 1-6 of the present invention have good foaming ability and foam stability in a clean water system. Among them, the foaming performance of the foaming agent GL-5 is relatively the best, which indicates that the foaming agent formed by dissolving sodium cocoyl isethionate, fatty alcohol polyoxyethylene ether 9 (AEO9), and lauramide propylamine oxide (LAO-30) in water at a mass ratio of 1:1:1 and a total concentration of 0.9wt% has the best performance. Compared with the foaming agent GL-5, the foaming ability and foam stability of the foaming agents of Comparative Examples 4-6 are poor. When the solution concentration is the same, the overall foam comprehensive index of the combined foaming agent increases. It shows that the foaming agent prepared by the present invention has good foaming and foam stabilizing properties.

[0087] 2. The influence of temperature on the liquid carrying performance of foaming agent

[0088] Table 7 Effect of different temperatures on the liquid carrying performance of the foaming agent

[0089]

[0090]

[0091] Table 7 shows the change of the liquid carrying rate of the foaming agent of the ternary compound system with temperature. It can be seen from Table 7 that with the increase of temperature, the liquid carrying rate of the foaming agent GL-1 gradually increases from 15.27% to 61.805%, the liquid carrying rate of the foaming agent GL-2 gradually increases from 15.27% to 75.64%, the liquid carrying rate of the foaming agent GL-3 gradually increases from 25.605% to 90.895%, the liquid carrying rate of the foaming agent GL-4 gradually increases from 29.92% to 92.545%, the liquid carrying rate of the foaming agent GL-5 gradually increases from 37.22% to 93.385%, and the liquid carrying rate of the foaming agent GL-6 gradually increases from 40.32% to 95.33%. This shows that with the increase of temperature, the potential capacity of the compound system is gradually increasing.

[0092] 3. Temperature resistance of foaming agent

[0093] Due to the variability of downhole temperature, the performance evaluation of the foaming agent needs to consider its temperature resistance. According to the on-site investigation, the temperature at the bottom of the Changqing gas well is generally above 60°C, and even as high as 100°C. Therefore, the nano foaming agent prepared in the above Examples 1-6 was tested for its temperature resistance at 80°C, and the results are shown in Table 8.

[0094] Table 8 Evaluation data of temperature resistance of different foaming agents (80℃)

[0095] Name of foaming agent Foam volume / mL Half-life / s Foam comprehensive index / mL s GL-1 360 240 64800.00 GL-2 375 310 87187.50 GL-3 400 315 94500.00 GL-4 445 395 131831.25 GL-5 463 443 153831.75 GL-6 426 417 133231.5

[0096] It can be seen from Table 8 that the foam volume of the foaming agent prepared in Examples 1-6 is not much different before and after at a high temperature of 80°C, and the foaming agent still maintains good foam stability, indicating that the foaming agent has good thermal stability and is suitable for use in Yanchang gas wells.

[0097] (II) Performance evaluation of foaming agent prepared by mineralization system

[0098] 1. Effect of mineralization on the liquid carrying performance of foaming agent

[0099] The liquid carrying rates of the foaming agents prepared in Examples 8-12 at 80°C are shown in Table 9.

[0100] Table 9 Liquid carrying rate of foaming agent at 80℃ (different mineralization)

[0101]

[0102] Note: GL-1*, GL-2*, GL-3*, GL-4*, GL-5* indicate that the compositions of the foaming agents (except the solvent used) are the same as those of Examples 1-5.

[0103] Table 9 shows the curve of the liquid carrying performance of the nano-composite system foaming agent as the mineralization changes. It can be seen from the table that as the mineralization increases, the liquid carrying rate of the nano foaming agent of Examples 8-12 gradually increases, which shows that the nano foaming agent of the present invention has stable liquid carrying performance at a high temperature of 80°C and a high mineralization.

[0104] 2. Foaming ability and foam stability in high mineralization (50000mg / L) system

[0105] The foaming ability and foam stability of the foaming agents prepared under the condition of a mineralization degree of 50,000 mg / L in Examples 7 and 8-13 and the foaming agents prepared in Comparative Examples 1-3 are shown in Table 10.

[0106] Table 10 Foaming ability and foam stability in high mineralization (50000 mg / L) system (80°C)

[0107] Foaming agent Foam volume / mL Half-life / s Foam comprehensive index / mL s Liquid carrying rate / % GL-1-50000 385 273 78828.75 55.99 GL-2-50000 376 385 108570 58.615 GL-3-50000 400 302 90600 67.52 GL-4-50000 445 421 140508.75 71.655 GL-5-50000 478 441 158098.5 73.34 GL-6-50000 453 387 131483.25 67.2 Example 7 370 345 95737.5 63.18 Comparative Example 1 325 185 45093.75 41.2 Comparative Example 2 360 210 56700 51.5 Comparative Example 3 385 275 79406.25 47.5

[0108] As can be seen from Table 10, at 80°C, the three comparative foaming agents all have strong foaming and liquid carrying capabilities for simulated mineral water, and their liquid carrying capabilities all reach more than 40%. Compared with comparative example 1, Example 1 has a higher foaming volume and a longer foam half-life, indicating that the anionic surfactant sodium coconut oil base isethionate in Example 1 has a synergistic effect. Compared with comparative example 2, Example 2 has a slightly higher foaming volume and a longer foam half-life, indicating that the performance of the foaming agent will decline after the nano-silica foam-stabilizing particles are removed. Compared with Comparative Example 3, Example 3 has a higher foaming volume and a longer foam half-life, indicating that the foaming agent preparation parameter ratio of Example 3 is better. At the same time, after sodium cocoyl isethionate, fatty alcohol polyoxyethylene ether 9 (AEO9), and lauryl amide propyl amine oxide (LAO-30) are mixed and compounded in a mass ratio of 1:1:1, the foaming ability and foam stability are greatly improved, indicating that the three have a significant synergistic effect. Among them, when the concentration of the foaming agent is 0.9%, the foaming ability and foam stability of the compounded foaming agent are the best. Considering comprehensively, the total compounding concentration of the three is 0.9%, which is more reasonable.

[0109] 3. On-site application effect

[0110] Generally speaking, the mineralization of formation water in high-salinity oil reservoirs can reach more than 10,000 mg / L (1.0%), and it not only contains high concentrations of monovalent counterions Na + , and will contain high concentrations of divalent counterions Ca 2+ Mg 2+ The salt resistance of different foaming agents was tested, as shown in Table 11.

[0111] Table 11 Evaluation data of salt resistance of different foaming agents (10000 mg / L, 80°C)

[0112] Name of foaming agent Foam volume / mL Half-life / s Foam comprehensive index / mL s GL-1-10000 310 215 49987.5 GL-2-10000 325 230 56062.5 GL-3-10000 340 260 66300.0 GL-4-10000 385 350 101062.5 GL-5-10000 410 380 116850.0 GL-6-10000 376 325 91650 GL-7-10000 370 365 101287.5

[0113] The above examples show that the initial foam volume and foam stability of the foaming agents GL-1 to GL-7 are reduced after adding salt ions. At the same time, the salinity of water also has a certain influence on the foaming agent. Under the condition of 80°C, without oil and methanol, and with a salinity of 10000 mg / L, the foaming agent still has good foaming ability. The field test results show that no incompatibility was found under the formation conditions of the Yanchang gas well, and ideal results were achieved.

[0114] The foaming agent of the present invention has lower surface tension. The present invention has strong foaming ability, produces rich and stable foam, and has moderate salt resistance and excellent foaming performance. The foaming agent has good compatibility with a variety of corrosion inhibitors and also has good corrosion inhibition ability. It has strong foaming ability, good stabilization effect, and strong liquid carrying capacity, and is suitable for gas wells of various temperatures and salinities. It performs well in extending the service life of gas wells and is conducive to large-scale application of on-site gas wells.

[0115] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0116] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or equivalent method that can be easily replaced by a person skilled in the art without creative labor falls within the protection scope of the present invention.

Claims

1. A nano foaming agent suitable for various temperature and mineralization environments, characterized in that: The nano foaming agent comprises anionic surfactant, nonionic surfactant, zwitterionic surfactant, foam-stabilizing particles and solvent; the total mass concentration of the anionic surfactant, nonionic surfactant and zwitterionic surfactant in the nano foaming agent is 0.1-1.0wt%, and the mass concentration of the foam-stabilizing particles is 0.1-0.5wt%; the mass ratio of the anionic surfactant, nonionic surfactant and zwitterionic surfactant is 10-30:15-20:15-25.

2. The nano foaming agent suitable for various temperature and mineralization environments according to claim 1, characterized in that: The total mass concentration of the anionic surfactant, the nonionic surfactant and the zwitterionic surfactant in the nano foaming agent is 0.5-0.9wt%.

3. The nano foaming agent suitable for various temperature and mineralization environments according to claim 1, characterized in that: The anionic surfactant is alkylphenol polyoxyethylene ether phosphate and / or sodium coconut oil isethionate.

4. The nano foaming agent suitable for various temperature and mineralization environments according to claim 1, characterized in that: The nonionic surfactant is fatty alcohol polyoxyethylene ether, preferably one of fatty alcohol polyoxyethylene ether 3, fatty alcohol polyoxyethylene ether 5, fatty alcohol polyoxyethylene ether 7, fatty alcohol polyoxyethylene ether 9 or a combination of two or more thereof, more preferably fatty alcohol polyoxyethylene ether 9.

5. The nano foaming agent suitable for various temperature and mineralization environments according to claim 1, characterized in that: The zwitterionic surfactant is one or a combination of two or more of cocoylpropyl sulfobetaine, lauramide propyl amine oxide, cocoyl propyl betaine, and cetearyl dimethyl hydroxypropyl sulfobetaine, and lauramide propyl amine oxide is more preferred.

6. The nano foaming agent suitable for various temperature and mineralization environments according to claim 1, characterized in that: The mass ratio of the anionic surfactant, the nonionic surfactant and the zwitterionic surfactant in the nano foaming agent is 1:1:

1.

7. The nano foaming agent suitable for various temperature and mineralization environments according to claim 1, characterized in that: The foam stabilizing particles are one of nano-silicon dioxide, carbon nanofiber CNF, and titanium dioxide nanoparticles, preferably nano-silicon dioxide; the particle size of the nano-silicon dioxide is 80-100nm; the particle size of the titanium dioxide nanoparticles is 80-100nm; the diameter of the carbon nanofiber CNF is 10-500nm and the length is 0.5-100μm.

8. The nano foaming agent suitable for various temperature and mineralization environments according to claim 1, characterized in that: The solvent is one or a combination of two or more of water, methanol, and ethanol; the water is deionized water, or water containing inorganic minerals; the water containing inorganic minerals is tap water, gas well formation water, gas well injection water, or mineralized water; the mineralization of the mineralized water is 10000 mg / L-50000 mg / L.

9. The method for preparing the nano foaming agent applicable to various temperature and mineralization environments as claimed in claim 1, comprising the following steps: At room temperature, anionic surfactants, nonionic surfactants and zwitterionic surfactants are added to a solvent to obtain a mixed solution, and then foam-stabilizing particles are added to the mixed solution and dispersed uniformly by ultrasonication to obtain the product.

10. Use of the nano foaming agent suitable for various temperature and salinity environments as claimed in claim 1 in gas well drainage and gas production, wherein the temperature of the gas well is 35-95°C, and the salinity of the gas well is 10000mg / L-50000mg / L.

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