A foaming drainage composite agent, a preparation method and application thereof

Abstract

The application relates to a foaming cleanup composite agent and a preparation method and application thereof, and belongs to the technical field of oil extraction. The foaming cleanup composite agent is composed of the following components: 3-6% of fluorocarbon-polyether nonionic surfactant, 2-5% of coconut oil fatty acid diethanolamide, 1-4% of betaine surfactant, 1-2% of phosphatidylcholine, 1-2% of sodium oleate, 0.5-1.5% of 1,3-propylene glycol, 0.5-1% of high-temperature stabilizer, 0.1-0.5% of di(lauryl glutamine) lysine sodium, 0.1-0.3% of nano silicon dioxide, and the balance of water; the fluorocarbon-polyether nonionic surfactant comprises one or both of perfluorohexyl ethyl alcohol polyoxyethylene ether and perfluorooctyl ethyl alcohol polyoxyethylene ether; the phosphatidylcholine comprises one or more of soybean phosphatidylcholine, egg yolk phosphatidylcholine and artificially synthesized phosphatidylcholine, and the phosphatidylcholine has the comprehensive performances of foaming, stable foaming, cleanup, high-temperature resistance and high-salt resistance.

Description

TECHNICAL FIELD

[0001] The application relates to a foaming cleanup composite agent and a preparation method and application thereof, and belongs to the technical field of oil extraction. BACKGROUND

[0002] When a tight oil reservoir is exploited, ordinary acid fracturing, preflush acid fracturing, multi-stage injection acid fracturing and composite sand acid fracturing processes are usually used to perform deep acid fracturing reconstruction on the reservoir to form a stable oil and gas flow channel and realize yield increase. In order to deal with the problem that the residual liquid of the gel breaking liquid / acid liquid of the fracturing fluid is difficult to flow back, a cleanup agent and a foaming agent are simultaneously added to the fracturing fluid / acid liquid of the tight reservoir, wherein the cleanup agent reduces the interfacial tension of the gel breaking liquid and reduces the capillary resistance, thereby facilitating the flow back, and the foaming agent forms a foam working liquid system in cooperation with the liquid nitrogen injection process, can reduce the static pressure of the liquid column, and can also supplement the formation energy, thereby promoting the flow back.

[0003] The tight oil reservoir is usually high in temperature and high in salinity. At present, the exploitation of the high-temperature and high-salinity reservoir is a technical difficulty in the current oil well development, and an important factor is that the chemical agent suitable for ordinary reservoirs cannot well adapt to the high-temperature and high-salinity reservoir conditions.

[0004] Patent CN109135718A discloses a preparation method of a fracturing acidizing foaming cleanup agent, wherein the foam stabilizing surfactant is mainly composed of zwitterionic surfactants. The dodecyl sulfobetaine molecules have high positive electric nature, are easy to associate with the negatively charged dodecyl sodium sulfate molecules, and can enhance the compounding effect to make up for the deficiency of the foamability of the foam stabilizing surfactant. Although the dodecyl sulfobetaine used in the patent has good foaming performance, it has the problem of poor high-temperature resistance. The scheme does not add a component conducive to improving the high-temperature stability.

[0005] Patent CN116262876A discloses a nano cleanup agent for fracturing working liquid of a tight gas reservoir and a preparation method thereof. The zwitterionic surfactant and the cationic surfactant are compounded to reduce the surface tension and reduce the capillary pressure. The trimethylolpentanol polyoxyethylene polyoxypropylene ether is used as a dispersant to overcome the capillary resistance and the frictional resistance of fluid flow. The silica generated surfactant is grafted with nano silicon dioxide, and the dispersibility is better, so that the performance of the product cleanup agent is stable. In the scheme, the addition of silica to the betaine type zwitterionic surfactant can improve the high-temperature resistance to a certain extent. However, the surfactants used in the scheme need to be improved in terms of cleanup performance and salt resistance, especially the cleanup performance.

[0006] Patent CN114437703A discloses a kind of high-efficiency composite foaming cleanup agent for fracturing and its preparation method, including 1~3% of alkyl sulfonate sodium salt, 0.5~1% of alkenyl sulfonate sodium, 15~20% of amine oxide surfactant, 2~5% of betaine surfactant, 0.5~1% of high-temperature stabilizer, which claims to be stable in foaming performance under water quality salinity 80 mg / ml, environmental temperature 150℃ or below, and can be applied to high-temperature and high-salt environment. Its betaine surfactant and high-temperature stabilizer are used together, which has certain foaming and high-temperature resistance performance, but its foam stability and cleanup performance need to be improved.

[0007] It can be seen that the foaming cleanup agent provided in the prior art still has little research on the performance of adapting to high-temperature and high-salinity reservoir development, and the formula can be optimized, and it cannot meet the comprehensive performance requirements of foaming performance, foam stability, cleanup performance, high-temperature resistance, and high-salt resistance for high-temperature and high-salinity reservoir development.

[0008] In order to solve the problem that the foaming cleanup agent in the prior art generally has one or two performance defects in comprehensive performance, it is necessary to design the formula of the foaming cleanup agent well, so as to provide a foaming cleanup agent that meets the comprehensive performance requirements of foaming performance, foam stability, cleanup performance, high-temperature resistance, and high-salt resistance. SUMMARY

[0009] In order to solve the above problems, a foaming cleanup composite agent suitable for high-temperature and high-salinity reservoirs and its preparation method and application are provided. The foaming cleanup composite agent provided in the present application can have good foaming performance, foam stability, cleanup performance, high-temperature resistance, and high-salt resistance by adjusting and combining the components, and is more suitable for use in high-temperature and high-salinity reservoir development with fracturing fluid / acid liquid, which can solve the problem that the foaming cleanup agent in the prior art generally has one or two performance defects.

[0010] The present application provides a foaming cleanup composite agent suitable for high-temperature and high-salinity reservoirs, which is composed of the following components in mass percentage: fluorocarbon-polyether nonionic surfactant 3~6%, coconut oil fatty acid diethanolamide 2~5%, betaine surfactant 1~4%, phosphatidylcholine 1~2%, sodium oleate 1~2%, 1,3-propanediol 0.5~1.5%, high-temperature stabilizer 0.5~1%, di(lauroylamide glutamine) lysine sodium 0.1~0.5%, nano-silicon dioxide 0.1~0.3%, and the balance is water;

[0011] The fluorocarbon-polyether nonionic surfactant includes one or both of perfluorohexyl ethyl alcohol polyoxyethylene ether and perfluorooctyl ethyl alcohol polyoxyethylene ether;

[0012] The phosphatidylcholine is selected from one or more of soybean phosphatidylcholine, egg yolk phosphatidylcholine, and artificially synthesized phosphatidylcholine.

[0013] The high-temperature stabilizer is one or more of polyvinyl alcohol, polyethylene glycol, and polypropylene glycol.

[0014] The foaming cleanup composite provided in the present application is constructed by matching fluorocarbon-polyether nonionic surfactants, and has good cleanup performance. In order to compensate for the poor foaming performance, betaine surfactants are added for matching, and coconut oil fatty acid diethanol amide and nano-silicon dioxide are added as foam stabilizers, wherein the nano-silicon dioxide is also beneficial to improving the high-temperature resistance of the foaming cleanup composite. The addition of phosphatidylcholine and sodium oleate for use in cooperation with the fluorocarbon-polyether nonionic surfactant can further improve the salt resistance of the foaming cleanup composite. It also includes auxiliary regulators with 1,3-propanediol and di(lauroylamide glutamine) lysine sodium as the core, which can improve the compatibility of nano-silicon dioxide, fluorocarbon-polyether nonionic surfactant, and phosphatidylcholine, thereby improving the high-temperature resistance of the entire foaming cleanup composite system, and also being beneficial to the improvement of the compatibility of sodium oleate, fluorocarbon-polyether nonionic surfactant, and phosphatidylcholine, thereby also improving the salt resistance.

[0015] It should be noted that those skilled in the art can select soybean phosphatidylcholine, egg yolk phosphatidylcholine, and artificially synthesized phosphatidylcholine as needed, which have the same structure and properties and can produce the same technical effects, wherein soybean phosphatidylcholine is abundant and relatively low in price, and can be used as a preferred source of phosphatidylcholine.

[0016] Optionally, the nano-silicon dioxide is silane coupling agent modified nano-silicon dioxide. It has been found through experiments that the compatibility of nano-silicon dioxide, fluorocarbon-polyether nonionic surfactant, and phosphatidylcholine can be further improved after surface modification of the nano-silicon dioxide, thereby further improving the high-temperature resistance of the entire foaming cleanup composite system.

[0017] Optionally, the silane coupling agent is selected from one or more of KH-550, KH-560, and KH-570. At present, silane coupling agent modification of nano-silicon dioxide is a relatively mature treatment method, and the nonpolar groups brought by the silane coupling agent are beneficial to improving the compatibility of nano-silicon dioxide, fluorocarbon-polyether nonionic surfactant, and phosphatidylcholine.

[0018] Optionally, the preparation method of the silane coupling agent modified nano-silicon dioxide comprises: uniformly dispersing nano-silicon dioxide in water to obtain a nano-silicon dioxide suspension, adding an acid-treated silane coupling agent to the nano-silicon dioxide suspension, and then heating and refluxing to obtain the silane coupling agent modified nano-silicon dioxide.

[0019] Optionally, the heating reflux reaction condition is 60-90℃ for 30-180 min.

[0020] Optionally, the mass ratio of the silane coupling agent to the nano-silica is 1:(3-10).

[0021] Optionally, the mass ratio of the silane coupling agent to the nano-silica is 1:(4-7).

[0022] Optionally, the average particle size of the nano-silica raw material is 100-300 nm. The nano-silica raw material with a slightly larger particle size has a better effect on improving the thermal stability.

[0023] Optionally, the molecular weight of the high-temperature stabilizer is 1000-20000. The person skilled in the art can select the molecular weight of the high-temperature stabilizer as needed.

[0024] Optionally, the betaine surfactant is one or more of cocamide propyl betaine, lauramide propyl betaine, octadecanamide propyl betaine, dodecyldi-hydroxyethyl betaine, octadecyldi-hydroxyethyl betaine, and dodecyldimethyl betaine. It should be noted that the person skilled in the art can select other betaine surfactants to replace the above-mentioned commonly used betaine surfactants.

[0025] The application provides a preparation method of the above-mentioned foaming cleanup composite agent suitable for high-temperature and high-salinity reservoirs, and the preparation method comprises the following steps: first, injecting a formula amount of water, and then adding a formula amount of fluorocarbon-polyether nonionic surfactant, coconut oil fatty acid diethanolamide, betaine surfactant, phosphatidylcholine, sodium oleate, and high-temperature stabilizer into the water in sequence under stirring, and then stirring until uniform, and then adding sodium di(lauramide glutamine) lysine, 1,3-propanediol, and nano-silica to be dissolved and stirred uniformly, thereby obtaining the foaming cleanup composite agent suitable for high-temperature and high-salinity reservoirs.

[0026] The application provides an application of the above-mentioned foaming cleanup composite agent suitable for high-temperature and high-salinity reservoirs in the preparation of a fracturing fluid for oil well fracturing construction.

[0027] Optionally, the temperature of the oil well is ≥120℃, and the salinity of the water is ≥150000 mg / L.

[0028] The beneficial effects of the application include but are not limited to:

[0029] 1. According to the foaming cleanup composite agent and its preparation method and application of the application, the foaming cleanup composite agent is suitable for high-salt and high-mineralization reservoirs and has good foaming performance, foam stability and cleanup performance, and is more suitable for use in high-temperature and high-mineralization reservoir exploitation than the foaming cleanup agent in the prior art.

[0030] 2. According to the foaming cleanup composite agent and its preparation method and application of the application, fluorocarbon-polyether nonionic surfactant is used as a core to be matched and constructed, betaine surfactant is added for cooperation, coconut oil fatty acid diethanolamide and nano-silicon dioxide are added as foam stabilizers, the nano-silicon dioxide is also beneficial to improving the high-temperature resistance, phosphatidylcholine and sodium oleate are added to further improve the salt resistance, and 1,3-propanediol and di(lauroylamide glutamine) lysine sodium are used as auxiliary regulators, which can improve the compatibility of the nano-silicon dioxide with the fluorocarbon-polyether nonionic surfactant and the phosphatidylcholine, thereby improving the high-temperature resistance and salt resistance.

[0031] 3. According to the foaming cleanup composite agent and its preparation method and application of the application, after the nano-silicon dioxide is surface-modified, the compatibility of the nano-silicon dioxide with the fluorocarbon-polyether nonionic surfactant and the phosphatidylcholine can be further improved, thereby further improving the high-temperature resistance of the entire foaming cleanup composite agent system.

[0032] 4. According to the foaming cleanup composite agent and its preparation method and application of the application, the average particle size of the nano-silicon dioxide raw material is 100-300 nm, and the nano-silicon dioxide raw material with a slightly larger particle size is selected, and the improvement effect on the thermal stability is better. DETAILED DESCRIPTION

[0033] The application will be described in detail below with reference to the examples, but the application is not limited to these examples. Unless otherwise specified, the raw materials and reagents in the examples of the application are purchased through commercial channels.

[0034] Example 1

[0035] The example provides a foaming cleanup composite agent, which is composed of the following components in mass percentage: perfluorohexylethanol polyoxyethylene ether 5%, coconut oil fatty acid diethanolamide 4%, cocamide propyl betaine 3%, soybean phosphatidylcholine 1.5%, sodium oleate 1.5%, 1,3-propanediol 1.0%, polyvinyl alcohol 0.8%, di(lauroylamide glutamine) lysine sodium 0.3%, nano-silicon dioxide 0.2%, and the balance is water.

[0036] The preparation method of the foaming drainage composite is as follows: first, inject the formula amount of water, and then add the formula amount of fluorocarbon-polyether nonionic surfactant, coconut oil fatty acid diethanolamide, betaine surfactant, phosphatidylcholine, sodium oleate, and high-temperature stabilizer into the water in sequence under stirring, uniformly stir, and then add sodium di(lauryl amidoglutamate) lysine, 1,3-propanediol, and nano-silicon dioxide (average particle size is 286 nm) to uniformly dissolve, so as to obtain the foaming drainage composite.

[0037] Example 2

[0038] The example provides a foaming drainage composite, which is composed of the following components in mass percentage: perfluorooctyl polyoxyethylene glycol alcohol 6%, coconut oil fatty acid diethanolamide 5%, dodecyl dimethyl betaine 4%, soybean phosphatidylcholine 2%, sodium oleate 2%, 1,3-propanediol 1.5%, polyethylene glycol 1%, sodium di(lauryl amidoglutamate) lysine 0.5%, nano-silicon dioxide 0.3%, and the balance is water.

[0039] The preparation method is the same as that in example 1.

[0040] Example 3

[0041] The example provides a foaming drainage composite, which is composed of the following components in mass percentage: perfluorooctyl polyoxyethylene glycol alcohol 6%, coconut oil fatty acid diethanolamide 5%, dodecyl dimethyl betaine 4%, soybean phosphatidylcholine 2%, sodium oleate 2%, 1,3-propanediol 1.5%, polyethylene glycol 1%, sodium di(lauryl amidoglutamate) lysine 0.5%, nano-silicon dioxide 0.3%, and the balance is water.

[0042] The preparation method is the same as that in example 1.

[0043] Example 4

[0044] The example is basically the same as example 1, except that the betaine surfactant is lauryl amidopropyl betaine.

[0045] Example 5

[0046] The example is basically the same as example 1, except that the betaine surfactant is octadecanoyl amidopropyl betaine.

[0047] Example 6

[0048] The present example is basically the same as example 1, except that the nanosilica is KH-570 modified nanosilica, and the preparation method thereof comprises: 1) preparing 100 mL of isopropyl alcohol, adding acetic acid to adjust the pH to 5.0, then adding 20 mL of water and 5 g of KH-570 and stirring uniformly for standby; 2) adding 20 g of nanosilica powder (average particle size of 286 nm) into water, and uniformly dispersing by using ultrasonic oscillation to obtain a silica suspension; 3) slowly adding the obtained KH-570 solution into the silica suspension, and refluxing at 70°C for 1 h; 4) filtering the product and washing it with ethanol for 2-3 times, and then drying the product at 105°C to obtain the KH-570 modified nanosilica.

[0049] Taking 3 g of unmodified nanosilica and adding it into 100 mL of paraffin liquid, after ultrasonic dispersion, it was found that it produced sedimentation after 5 days; taking 3 g of KH-570 modified nanosilica and adding it into 100 mL of paraffin liquid, after the same ultrasonic dispersion treatment, no sedimentation was produced after 20 days, indicating that the modified nanosilica has improved organic compatibility, and it can better compatible with the organic phase.

[0050] Example 7

[0051] The present example is basically the same as example 6, except that KH-560 modified nanosilica is used.

[0052] Example 8

[0053] The present example is basically the same as example 6, except that KH-550 modified nanosilica is used.

[0054] Comparative Example 1

[0055] The present comparative example is basically the same as example 1, except that it does not contain polyvinyl alcohol.

[0056] Comparative Example 2

[0057] The present comparative example is basically the same as example 1, except that it does not contain nanosilica.

[0058] Comparative Example 3

[0059] The present comparative example is basically the same as example 1, except that it does not contain di(lauroylamido glutamoyl) lysine sodium.

[0060] Comparative Example 4

[0061] The present comparative example is basically the same as example 1, except that it does not contain propylene glycol.

[0062] Comparative Example 5

[0063] The comparative example is basically the same as example 1, except that it does not contain soybean phosphatidylcholine and sodium oleate.

[0064] Test Example 1

[0065] The performance of the foaming cleanup composite in the examples and comparative examples was tested, and the results are shown in Table 1 below.

[0066] Foaming volume (mL) and half-life (s): The testing device and method in the paper “Development of Performance Evaluation Device for High Temperature and High Pressure Foaming Agent and Screening and Evaluation of Foaming Agent System” (Zheng Jilong, Applied Science and Technology, 2016, 43(4): 27-30) were referred to, and the measurement was carried out at 120°C and 60 MPa, a salinity of 150000 mg / L was prepared, 1 wt% of the foaming cleanup composite to be tested was added, N2 was introduced, the foam generator was set to 5000 rpm, stirring was carried out for 180 s, and then the foaming volume (mL) and the time for the foam volume to be reduced by half were measured as the foam half-life (s).

[0067] Surface tension (mN / m) and contact angle (°): The surface tension of the foaming cleanup composite to be tested was determined using a surface tension tester (K100 type surface tension meter, Germany Kruss), and the contact angle on the rock surface was measured using a contact angle measuring instrument (DSA-100 type contact angle measuring instrument, Germany Kruss).

[0068] Fracturing fluid flowback rate (%): The displacement device was used to determine the fracturing fluid flowback rate (%) according to Q / SH 0054-2007 “Technical Requirements for Cleanup Agent for Fracturing and Acidizing”, and the test temperature was 120°C.

[0069] Table 1 Performance test results of foaming cleanup composite in examples and comparative examples

[0070]

[0071] According to the results in Table 1, the foaming cleanup composite provided by the present application has good foaming and stable foaming capacity under high temperature and high salt conditions, and also has good comprehensive performance of reducing surface tension and promoting fracturing fluid flowback.

[0072] Among them, fluorocarbon-polyether nonionic surfactant is used as the core, and the surfactant combination of betaine surfactant, sodium oleate and phosphatidylcholine has the comprehensive performance of cleanup, foaming and salt resistance, high temperature resistance, and the auxiliary foam stabilizer system of coconut oil fatty acid diethanolamide and nanosilica has good foam stabilizing effect, and the nanosilica cooperates with the auxiliary regulator of 1,3-propanediol and di(lauroylamide glutamine) lysine sodium as the core, which can improve the comprehensive performance of the foaming cleanup composite under high temperature conditions.

[0073] According to the results of Comparative Examples 1 and 2, it can be seen that polyvinyl alcohol and nano-silica can significantly improve the high-temperature resistance of the system in the application scheme, and especially play an important role in the bubble and stable bubble performance.

[0074] According to the results of Comparative Examples 3 and 4, it can be seen that the auxiliary system of sodium di(lauroylamide glutamine) lysine and propylene glycol as the core has an important influence on the overall high-temperature resistance of the system, and especially plays an important role in improving the stable bubble capacity. This auxiliary system can improve the dispersibility of nano-silica in the whole system, which is beneficial to the protection of nano-silica on fluorocarbon-polyether nonionic surfactant, betaine surfactant, sodium oleate and phosphatidylcholine and other surfactants.

[0075] According to the results of Comparative Example 5, it can be seen that soybean phosphatidylcholine and sodium oleate have important significance for improving salt resistance, and especially play an important role in improving the surface tension and fracturing fluid displacement performance.

[0076] The above is only an embodiment of the application, and the protection scope of the application is not limited by these specific embodiments, but is determined by the claims of the application. The application can have various changes and variations for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the technical thought and principle of the application shall be included in the protection scope of the application.

Claims

1. A foaming cleanup composite agent characterized by comprising: consists of the following components by mass percentage: fluorocarbon-polyether nonionic surfactant 3-6%, coconut oil fatty acid diethanolamide 2-5%, betaine surfactant 1-4%, phosphatidylcholine 1-2%, sodium oleate 1-2%, 1,3-propanediol 0.5-1.5%, high-temperature stabilizer 0.5-1%, di(lauryl amidoglutamine) lysine sodium 0.1-0.5%, silane coupling agent modified nano-silica 0.1-0.3%, and the balance being water; The fluorocarbon-polyether nonionic surfactant comprises one or both of perfluorohexyl ethyl alcohol polyoxyethylene ether and perfluorooctyl ethyl alcohol polyoxyethylene ether. The phosphatidylcholine is selected from one or more of soybean phosphatidylcholine, egg yolk phosphatidylcholine, and artificially synthesized phosphatidylcholine. The high-temperature stabilizer is one or more of polyvinyl alcohol, polyethylene glycol, and polypropylene glycol.

2. The bubble-assisted drain composite of claim 1, wherein, The silane coupling agent is selected from one or more of KH-550, KH-560, and KH-570.

3. The bubble-assisted drain composite of claim 2, wherein, The preparation method of the silane coupling agent modified nano-silica comprises: uniformly dispersing nano-silica in water to obtain a silica suspension, adding an acid-treated silane coupling agent to the silica suspension, and then heating and refluxing to obtain the silane coupling agent modified nano-silica.

4. The foaming co-synergist of claim 3, wherein, The average particle size of the nano-silica raw material is 100-300 nm.

5. The bubble-assisted drain composite of claim 1, wherein, The betaine surfactant is one or more of cocamide propyl betaine, lauryl amidopropyl betaine, stearamidopropyl betaine, dodecyldihydroxyethyl betaine, octadecyldihydroxyethyl betaine, and dodecyldimethyl betaine.

6. The method of claim 1-5, wherein the foaming surfactant composition is prepared by the steps of: The preparation method comprises the following steps: first, injecting a formula amount of water, and then, under stirring, sequentially adding a formula amount of fluorocarbon-polyether nonionic surfactant, coconut oil fatty acid diethanolamide, betaine surfactant, phosphatidylcholine, sodium oleate, and high-temperature stabilizer into the water, stirring until uniform, and then, adding di(lauryl amidoglutamine) lysine sodium, 1,3-propanediol, and nano-silica, stirring until dissolved, to obtain the foaming and cleanup composite.

7. Use of the foaming and cleanup composite according to any one of claims 1-5 in the preparation of a fracturing fluid for oil well fracturing construction.

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