Nanoparticle stable foam oil-displacing agent as well as preparation method and application thereof

Abstract

The invention relates to a nanoparticle stable foam oil-displacing agent and a preparation method and application thereof, in particular to the technical field of oilfield development, and the oil-displacing agent comprises a first surfactant, alcohol, water, an organic solvent, a silicon source precursor and a second surfactant; the mass ratio of the first surfactant to the alcohol to the water is (0.2-1): (0.2-1): 20; the mass ratio of the organic solvent to the total amount of the first surfactant, the alcohol and the water is (0.5-5): 100; the mass ratio of the silicon source precursor to the total amount of the first surfactant, the alcohol, the water and the organic solvent is (0.1-1): 20; the mass ratio of the second surfactant to the total amount of the first surfactant, the alcohol, the water, the organic solvent and the silicon source precursor is (0.1-1): 100. According to the oil-displacing agent provided by the invention, a good oil-displacing effect is achieved by utilizing the synergistic effect of all the components, oil-displacing foam is stable in the oil-displacing process, and the good oil-displacing effect can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield development, and in particular to a nanoparticle-stabilized foam oil-displacing agent, a preparation method thereof, and application thereof. Background Art

[0002] Foam flooding, which effectively expands the swept volume and significantly improves oil washing efficiency, has become an increasingly important method for enhancing oil recovery. Foam stability is a key factor influencing its effectiveness, directly affecting the displacement time and distance of the foam within the porous reservoir medium. Polymers are typically added to the foam system to increase the mechanical strength and viscosity of the foam film and slow its collapse. However, the addition of polymers can lead to excessive injection pressures during foam injection, making it difficult to inject. Furthermore, polymers tend to remain in the reservoir, causing some damage to the reservoir environment. This makes this method less suitable for low-permeability reservoirs.

[0003] Nanoparticles also exhibit unique surface, interfacial, and small-size effects. They irreversibly adsorb at the gas / liquid interface of foams, forming a staggered distribution along the foam wall, forming a dense shell-like structure. This blocks water flow channels, inhibits water flow, slows the drainage of the foam film, and reduces the contact area between bubbles, inhibiting bubble coalescence and disproportionation, thereby significantly improving foam stability. Furthermore, because nanoparticles are much smaller than the pore throats of the reservoir, they do not damage the reservoir during migration. Therefore, nanoparticles offer significant advantages and promising application prospects in foam stabilization.

[0004] The existing technology usually redisperses the nanoparticles that are completely separated from the synthetic solution for use in stabilizing foam. However, this method requires the aggregated nanoparticles to be dispersed again, which is costly to use. At the same time, the redispersed nanoparticles are much more likely to agglomerate than those that have not been separated from the synthetic solution, which seriously affects the foam stabilization effect. Therefore, some new nanoparticle foam stabilization technologies have emerged in recent years. For example, CN111253922A discloses an in-situ self-generated nanoparticle stabilized foam system and its preparation and application. Taking the total weight of the in-situ self-generated nanoparticle stabilized foam system as 100%, its raw material composition includes: 0.5%-5% silicate, 0.1%-1.0% biosurfactant alkyl glycoside and the remainder brine. The foam system provided is an in-situ self-generated nanoparticle stabilized foam. The raw material silicate of the foam system can react with the divalent metal ions contained in the brine, such as Ca 2 + Mg 2+ 、Ba 2+ and Sr 2+The method can form inorganic nanoparticles by chemical reaction, without the need to add modified nanoparticles, with low cost and simple operation. The formula has better adaptability under high temperature and high salinity oil reservoir conditions, but the method requires the two reactants to contact and react in the formation, which is difficult to achieve given the complexity of the formation.

[0005] In summary, the existing foam flooding methods still have the problems of poor oil displacement foam stability and low oil displacement efficiency. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a nanoparticle-stabilized foam oil displacement agent and its preparation method and use, so as to solve the problems of poor oil displacement foam stability and low oil displacement efficiency still existing in the existing foam oil displacement methods.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a nanoparticle-stabilized foam oil-displacing agent, the nanoparticle-stabilized foam oil-displacing agent comprising:

[0009] A first surfactant, alcohol, water, an organic solvent, a silicon source precursor, and a second surfactant;

[0010] The mass ratio of the first surfactant, alcohol and water is (0.2-1):(0.2-1):20;

[0011] The mass ratio of the organic solvent to the total amount of the first surfactant, alcohol and water is (0.5-5):100;

[0012] The mass ratio of the silicon source precursor to the total amount of the first surfactant, alcohol, water and organic solvent is (0.1-1):20;

[0013] The mass ratio of the second surfactant to the total amount of the first surfactant, alcohol, water, organic solvent and silicon source precursor is (0.1-1):100.

[0014] The nanoparticle-stabilized foam oil-displacing agent provided by the present invention achieves a good oil-displacing effect by designing the oil-displacing agent formula and utilizing the synergistic effect between the various components. The oil-displacing foam is stable during the oil-displacing process, thereby achieving a good oil-displacing effect and significantly improving the oil-displacing efficiency.

[0015] As a preferred technical solution of the present invention, the first surfactant includes one or a combination of at least two of di(2-ethylhexyl) sodium sulfosuccinate, nonylphenol polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, sorbitan monolaurate or sodium dodecylbenzenesulfonate.

[0016] Preferably, the alcohol includes one or a combination of at least two of n-butanol, isopropanol or ethanol.

[0017] Preferably, the organic solvent comprises one or a combination of at least two of dichloromethane, chloroform or N,N-dimethylformamide.

[0018] Preferably, the silicon source precursor includes one or a combination of at least two of ethyl silicate, phenyltrimethoxysilane, 3-aminopropyltriethoxysilane or vinyltriethoxysilane.

[0019] Preferably, the second surfactant comprises one or a combination of at least two of sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium bromide, sodium α-olefinsulfonate, sorbitan monooleate or sodium di(2-ethylhexyl)sulfosuccinate.

[0020] As a preferred technical solution of the present invention, the first surfactant is one or a combination of at least two of sodium di(2-ethylhexyl)sulfosuccinate and sodium dodecylbenzenesulfonate in a mass ratio of 1:(0.8-1).

[0021] Preferably, the silicon source precursor is one or a combination of at least two of ethyl silicate, phenyltrimethoxysilane or 3-aminopropyltriethoxysilane.

[0022] Preferably, the second surfactant is sodium dodecylbenzenesulfonate.

[0023] In a second aspect, the present invention provides a method for preparing the nanoparticle-stabilized foam oil-displacing agent as described in the first aspect, the preparation method comprising:

[0024] Ingredients are proportioned according to mass;

[0025] performing a first mixing of a first surfactant, alcohol, and water to obtain a first mixed solution;

[0026] adding an organic solvent to the obtained first mixed solution for second mixing to obtain a second mixed solution;

[0027] adding a silicon source precursor to the obtained second mixed solution for a third mixing to obtain a third mixed solution;

[0028] The second surfactant is added to the obtained third mixed liquid to perform a fourth mixing to obtain a nanoparticle-stabilized foam oil-displacing agent.

[0029] As a preferred technical solution of the present invention, the stirring speed of the first mixing is 200-800 r / min.

[0030] Preferably, the first mixing time is 5-20 minutes.

[0031] Preferably, the stirring speed of the second mixing is 500-1000 r / min.

[0032] Preferably, the second mixing time is 15-30 minutes.

[0033] As a preferred technical solution of the present invention, the stirring speed of the third mixing is 300-1000 r / min.

[0034] Preferably, the third mixing time is 3-24 hours.

[0035] Preferably, the stirring speed of the fourth mixing is 400-600 r / min.

[0036] Preferably, the fourth mixing time is 20-35 minutes.

[0037] In a third aspect, the present invention provides a use of the nanoparticle-stabilized foam oil-displacing agent as described in the first aspect, wherein the use comprises: using the nanoparticle-stabilized foam oil-displacing agent to carry out oil displacement.

[0038] As a preferred technical solution of the present invention, the use includes: mixing the nanoparticle stabilized foam oil displacement agent and oil field injection water, and then performing the first injection and the second injection.

[0039] As a preferred technical solution of the present invention, the mass ratio of the nanoparticle-stabilized foam oil-displacing agent to the oilfield injection water in the mixture is 1:(10-1000).

[0040] As a preferred technical solution of the present invention, the amount of the mixed logistics injected in the first injection is 0.2-1PV.

[0041] Preferably, the material injected in the second injection includes gas.

[0042] Preferably, the material injected in the second injection includes one or a combination of at least two of nitrogen, air, carbon dioxide or flue gas.

[0043] Preferably, the amount of the injected material in the second injection is 0.1-2PV.

[0044] Compared with the existing technical solutions, the present invention has the following beneficial effects:

[0045] (1) The nanoparticle-stabilized foam flooding agent provided by the present invention has good dispersion performance of native nanoparticles and is not easy to agglomerate, which significantly enhances the stability of the foam. Compared with foam flooding alone, it can increase the crude oil recovery rate by more than 12 percentage points, and the recovery rate of oil flooding is ≥57.9%.

[0046] (2) The nanoparticle-stabilized foam flooding agent provided by the present invention does not require the original nanoparticles to be dispersed again, which can reduce the use cost of traditional nanoparticle foam flooding by more than 20%. DETAILED DESCRIPTION

[0047] To better illustrate the present invention and facilitate understanding of the technical solutions of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0048] This embodiment provides a nanoparticle-stabilized foam oil-displacing agent, which comprises:

[0049] A first surfactant, alcohol, water, an organic solvent, a silicon source precursor, and a second surfactant;

[0050] The mass ratio of the first surfactant, alcohol and water is (0.2-1):(0.2-1):20;

[0051] The mass ratio of the organic solvent to the total amount of the first surfactant, alcohol and water is (0.5-5):100;

[0052] The mass ratio of the silicon source precursor to the total amount of the first surfactant, alcohol, water and organic solvent is (0.1-1):20;

[0053] The mass ratio of the second surfactant to the total amount of the first surfactant, alcohol, water, organic solvent and silicon source precursor is (0.1-1):100.

[0054] The oil-displacing agent provided by the present invention, leveraging the surface, interfacial, and small-size effects of nanoparticles, can irreversibly adsorb onto the gas / liquid interface of the foam, forming a staggered distribution on the foam wall to form a dense shell-like structure. This blocks water flow channels, prevents water flow, slows the drainage of the foam liquid film, and simultaneously reduces the contact area between bubbles, inhibiting bubble coalescence and disproportionation, thereby significantly improving the stability of the foam. Furthermore, the oil-displacing agent provided by the present invention directly uses synthesized nanoparticles, eliminating the need for separation and redispersion, making them less prone to agglomeration and reducing their cost.

[0055] In the present invention, the mass ratio of the first surfactant, alcohol and water is (0.2-1): (0.2-1): 20, for example, it can be 0.2: 0.2: 20, 0.3: 0.2: 20, 0.4: 0.2: 20, 0.5: 0.2: 20, 0.6: 0.2: 20, 0.7: 0.2: 20, 0.8: 0.2: 20, 0.9: 0.2: 20, 1: 0.2: 20, 0.2: 0.3: 20, 0.2: 0.4 :20, 0.2:0.5:20, 0.2:0.6:20, 0.2:0.7:20, 0.2:0.8:20, 0.2:0.9:20, 0.2:1:20, 0.3:0.4:20, 0.4:0.5:20, 0.5:0.6:20, 0.7:0.8:20, 0.8:0.9:20 or 0.9:1:20, etc., but not limited to the listed values. Other values ​​not listed within the range also meet the requirements.

[0056] In the present invention, the mass ratio of the organic solvent to the total mass of the first surfactant, alcohol and water is (0.5-5):100, which refers to the ratio of the mass of the organic solvent to the total mass of the first surfactant, alcohol and water. For example, it can be 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, 1:100, 1.5:100, 2:100, 2.5:100, 3:100, 3.5:100, 4:100, 4.5:100 or 5:100, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0057] In the present invention, the mass ratio of the silicon source precursor to the total amount of the first surfactant, alcohol, water and organic solvent is (0.1-1):20, which refers to the ratio of the mass of the silicon source precursor to the total mass of the first surfactant, alcohol, water and organic solvent. For example, it can be 0.1:20, 0.2:20, 0.3:20, 0.4:20, 0.5:20, 0.6:20, 0.7:20, 0.8:20, 0.9:20 or 1:20, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0058] In the present invention, the mass ratio of the second surfactant to the total mass of the first surfactant, alcohol, water, organic solvent and silicon source precursor is (0.1-1):100, which refers to the ratio of the mass of the second surfactant to the total mass of the first surfactant, alcohol, water, organic solvent and silicon source precursor. For example, it can be 0.1:100, 0.2:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100 or 1:100, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0059] Specifically, the first surfactant includes one or a combination of at least two of sodium di(2-ethylhexyl)sulfosuccinate, nonylphenol polyoxyethylene ether (average molecular weight of 199.16 g / mol), sorbitan monooleate polyoxyethylene ether (average molecular weight of 1310 g / mol), sorbitan monolaurate or sodium dodecylbenzenesulfonate.

[0060] Specifically, the alcohol includes one or a combination of at least two of n-butanol, isopropanol or ethanol.

[0061] Specifically, the organic solvent includes one or a combination of at least two of dichloromethane, chloroform or N,N-dimethylformamide.

[0062] Specifically, the silicon source precursor includes one or a combination of at least two of ethyl silicate, phenyltrimethoxysilane, 3-aminopropyltriethoxysilane or vinyltriethoxysilane.

[0063] Specifically, the second surfactant includes one or a combination of at least two of sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium bromide, sodium α-olefinsulfonate, sorbitan monooleate or sodium di(2-ethylhexyl)sulfosuccinate.

[0064] Furthermore, the present invention provides a method for preparing the nanoparticle-stabilized foam oil-displacing agent as described above, the preparation method comprising:

[0065] Ingredients are proportioned according to mass;

[0066] performing a first mixing of a first surfactant, alcohol, and water to obtain a first mixed solution;

[0067] adding an organic solvent to the obtained first mixed solution for second mixing to obtain a second mixed solution;

[0068] adding a silicon source precursor to the obtained second mixed solution for a third mixing to obtain a third mixed solution;

[0069] The second surfactant is added to the obtained third mixed liquid to perform a fourth mixing to obtain a nanoparticle-stabilized foam oil-displacing agent.

[0070] The stirring speed of the first mixing is 200-800 r / min, for example, it can be 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min or 800 r / min, but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0071] The first mixing time is 5-20 min, for example, 5 min, 10 min, 15 min or 20 min, etc., but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0072] The stirring speed of the second mixing is 500-1000 r / min, for example, it can be 500 r / min, 600 r / min, 700 r / min, 800 r / min, 900 r / min or 1000 r / min, but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0073] The second mixing time is 15-30 min, for example, 15 min, 20 min, 25 min or 30 min, but is not limited to the listed values. Other values ​​not listed within the range also meet the requirements.

[0074] Wherein, the stirring speed of the third mixing is 300-1000r / min, for example, it can be 300r / min, 400r / min, 500r / min, 600r / min, 700r / min, 800r / min, 900r / min or 1000r / min, but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0075] The third mixing time is 3-24 hours, for example, 3 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours, etc., for example, it can be, but not limited to, the listed values, and other unlisted values ​​within the range also meet the requirements.

[0076] Among them, the stirring speed of the fourth mixing is 400-600r / min, for example, it can be 400r / min, 450r / min, 500r / min, 550r / min or 600r / min, but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0077] The fourth mixing time is 20-35 min, for example, 20 min, 25 min, 30 min or 35 min, but is not limited to the listed values. Other values ​​not listed within the range also meet the requirements.

[0078] Furthermore, the present invention provides a nanoparticle-stabilized foam flooding method, which is carried out using the nanoparticle-stabilized foam flooding agent as described above.

[0079] Specifically, the nanoparticle-stabilized foam flooding method includes: mixing the nanoparticle-stabilized foam flooding agent and oilfield injection water, and then performing a first injection and a second injection.

[0080] Wherein, the mass ratio of the nanoparticle-stabilized foam oil-displacing agent to the oilfield injection water in the mixture is 1:(10-1000), for example, it can be 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900 or 1:1000, etc., but is not limited to the listed values, and other values ​​not listed within this range also meet the requirements.

[0081] Among them, the amount of the mixed logistics injected in the first injection is 0.2-1PV, for example, it can be 0.2PV, 0.3PV, 0.4PV, 0.5PV, 0.6PV, 0.7PV, 0.8PV, 0.9PV or 1PV, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0082] Wherein, the material injected in the second injection includes gas.

[0083] The material injected in the second injection includes one or a combination of at least two of nitrogen, air, carbon dioxide or flue gas.

[0084] Among them, the amount of material injected in the second injection is 0.1-2PV, for example, it can be 0.1PV, 0.2PV, 0.4PV, 0.6PV, 0.8PV, 1PV, 1.2PV, 1.4PV, 1.6PV, 1.8PV or 2PV, etc., but is not limited to the listed values. Other unlisted values ​​within this range also meet the requirements.

[0085] Furthermore, in order to illustrate the good oil displacement effect of the nanoparticle-stabilized foam oil displacement agent provided by the present invention, actual examples are used for illustration, as follows:

[0086] Example 1

[0087] This embodiment provides a nanoparticle-stabilized foam oil-displacing agent, which comprises:

[0088] A first surfactant, alcohol, water, an organic solvent, a silicon source precursor, and a second surfactant;

[0089] The mass ratio of the first surfactant, alcohol and water is 0.4:0.7:20;

[0090] The mass ratio of the organic solvent to the total amount of the first surfactant, alcohol and water is 2.5:100;

[0091] The mass ratio of the silicon source precursor to the total amount of the first surfactant, alcohol, water and organic solvent is 0.3:20;

[0092] The mass ratio of the second surfactant to the total amount of the first surfactant, alcohol, water, organic solvent and silicon source precursor is 0.3:100;

[0093] The first surfactant is nonylphenol polyoxyethylene ether (average molecular weight is 199.16 g / mol);

[0094] The alcohol is ethanol;

[0095] The organic solvent is chloroform;

[0096] The silicon source precursor is phenyltrimethoxysilane;

[0097] The second surfactant is cetyltrimethylammonium bromide.

[0098] The preparation process is as follows:

[0099] Ingredients are proportioned according to mass;

[0100] performing a first mixing of a first surfactant, alcohol, and water to obtain a first mixed solution;

[0101] adding an organic solvent to the obtained first mixed solution for second mixing to obtain a second mixed solution;

[0102] adding a silicon source precursor to the obtained second mixed solution for a third mixing to obtain a third mixed solution;

[0103] adding a second surfactant to the obtained third mixed liquid for a fourth mixing to obtain a nanoparticle-stabilized foam oil displacement agent;

[0104] Among them, the stirring speed of the first mixing is 400r / min; the time of the first mixing is 10min; the stirring speed of the second mixing is 800r / min; the time of the second mixing is 20min; the stirring speed of the third mixing is 800r / min; the time of the third mixing is 15h; the stirring speed of the fourth mixing is 450r / min; and the time of the fourth mixing is 25min.

[0105] Example 2

[0106] This embodiment provides a nanoparticle-stabilized foam oil-displacing agent, which comprises:

[0107] A first surfactant, alcohol, water, an organic solvent, a silicon source precursor, and a second surfactant;

[0108] The mass ratio of the first surfactant, alcohol and water is 0.7:0.4:20;

[0109] The mass ratio of the organic solvent to the total amount of the first surfactant, alcohol and water is 3.5:100;

[0110] The mass ratio of the silicon source precursor to the total amount of the first surfactant, alcohol, water and organic solvent is 0.6:20;

[0111] The mass ratio of the second surfactant to the total amount of the first surfactant, alcohol, water, organic solvent and silicon source precursor is 0.6:100;

[0112] The first surfactant is sodium di(2-ethylhexyl)sulfosuccinate;

[0113] The alcohol is n-butanol;

[0114] The organic solvent is dichloromethane;

[0115] The silicon source precursor is ethyl silicate;

[0116] The second surfactant is sodium dodecylbenzenesulfonate.

[0117] The preparation process is as follows:

[0118] Ingredients are proportioned according to mass;

[0119] performing a first mixing of a first surfactant, alcohol, and water to obtain a first mixed solution;

[0120] adding an organic solvent to the obtained first mixed solution for second mixing to obtain a second mixed solution;

[0121] adding a silicon source precursor to the obtained second mixed solution for a third mixing to obtain a third mixed solution;

[0122] adding a second surfactant to the obtained third mixed liquid for a fourth mixing to obtain a nanoparticle-stabilized foam oil displacement agent;

[0123] Among them, the stirring speed of the first mixing is 600 r / min; the time of the first mixing is 15 minutes; the stirring speed of the second mixing is 600 r / min; the time of the second mixing is 25 minutes; the stirring speed of the third mixing is 600 r / min; the time of the third mixing is 10 hours; the stirring speed of the fourth mixing is 500 r / min; and the time of the fourth mixing is 30 minutes.

[0124] Example 3

[0125] This embodiment provides a nanoparticle-stabilized foam oil-displacing agent, which comprises:

[0126] A first surfactant, alcohol, water, an organic solvent, a silicon source precursor, and a second surfactant;

[0127] The mass ratio of the first surfactant, alcohol and water is 1:0.2:20;

[0128] The mass ratio of the organic solvent to the total amount of the first surfactant, alcohol and water is 5:100;

[0129] The mass ratio of the silicon source precursor to the total amount of the first surfactant, alcohol, water and organic solvent is 0.1:20;

[0130] The mass ratio of the second surfactant to the total amount of the first surfactant, alcohol, water, organic solvent and silicon source precursor is 1:100;

[0131] The first surfactant is sorbitan monolaurate;

[0132] The alcohol is n-butanol;

[0133] The organic solvent is chloroform;

[0134] The silicon source precursor is vinyltriethoxysilane;

[0135] The second surfactant is sorbitan monooleate.

[0136] The preparation process is as follows:

[0137] Ingredients are proportioned according to mass;

[0138] performing a first mixing of a first surfactant, alcohol, and water to obtain a first mixed solution;

[0139] adding an organic solvent to the obtained first mixed solution for second mixing to obtain a second mixed solution;

[0140] adding a silicon source precursor to the obtained second mixed solution for a third mixing to obtain a third mixed solution;

[0141] adding a second surfactant to the obtained third mixed liquid for a fourth mixing to obtain a nanoparticle-stabilized foam oil displacement agent;

[0142] Among them, the stirring speed of the first mixing is 200 r / min; the time of the first mixing is 20 min; the stirring speed of the second mixing is 500 r / min; the time of the second mixing is 30 min; the stirring speed of the third mixing is 300 r / min; the time of the third mixing is 24 h; the stirring speed of the fourth mixing is 600 r / min; and the time of the fourth mixing is 20 min.

[0143] Example 4

[0144] This embodiment provides a nanoparticle-stabilized foam oil-displacing agent, which comprises:

[0145] A first surfactant, alcohol, water, an organic solvent, a silicon source precursor, and a second surfactant;

[0146] The mass ratio of the first surfactant, alcohol and water is 0.2:1:20;

[0147] The mass ratio of the organic solvent to the total amount of the first surfactant, alcohol and water is 0.5:100;

[0148] The mass ratio of the silicon source precursor to the total amount of the first surfactant, alcohol, water and organic solvent is 1:20;

[0149] The mass ratio of the second surfactant to the total amount of the first surfactant, alcohol, water, organic solvent and silicon source precursor is 0.1:100;

[0150] The first surfactant is sorbitan monooleate polyoxyethylene ether (average molecular weight is 1310 g / mol);

[0151] The alcohol is isopropyl alcohol;

[0152] The organic solvent is N,N-dimethylformamide;

[0153] The silicon source precursor is 3-aminopropyltriethoxysilane;

[0154] The second surfactant is sodium α-olefin sulfonate.

[0155] The preparation process is as follows:

[0156] Ingredients are proportioned according to mass;

[0157] performing a first mixing of a first surfactant, alcohol, and water to obtain a first mixed solution;

[0158] adding an organic solvent to the obtained first mixed solution for second mixing to obtain a second mixed solution;

[0159] adding a silicon source precursor to the obtained second mixed solution for a third mixing to obtain a third mixed solution;

[0160] adding a second surfactant to the obtained third mixed liquid for a fourth mixing to obtain a nanoparticle-stabilized foam oil displacement agent;

[0161] Among them, the stirring speed of the first mixing is 800r / min; the time of the first mixing is 5min; the stirring speed of the second mixing is 1000r / min; the time of the second mixing is 15min; the stirring speed of the third mixing is 1000r / min; the time of the third mixing is 3h; the stirring speed of the fourth mixing is 400r / min; and the time of the fourth mixing is 35min.

[0162] Example 5

[0163] The only difference from Example 1 is that the first surfactant is sodium di(2-ethylhexyl)sulfosuccinate and sodium dodecylbenzenesulfonate in a mass ratio of 1:1.

[0164] Example 6

[0165] The only difference from Example 1 is that the mass ratio of the first surfactant, alcohol and water is 0.5:1:20.

[0166] Example 7

[0167] The only difference from Example 1 is that the mass ratio of the organic solvent to the total amount of the first surfactant, alcohol and water is 1:100.

[0168] Example 8

[0169] The only difference from Example 1 is that the mass ratio of the silicon source precursor to the total amount of the first surfactant, alcohol, water and organic solvent is 0.2:20.

[0170] Example 9

[0171] The only difference from Example 1 is that the silicon source precursor is ethyl silicate, phenyltrimethoxysilane and 3-aminopropyltriethoxysilane in a mass ratio of 1:1:1.

[0172] Example 10

[0173] The only difference from Example 1 is that the mass ratio of the second surfactant to the total amount of the first surfactant, alcohol, water, organic solvent and silicon source precursor is 0.2:100.

[0174] The nanoparticle-stabilized foam flooding agent obtained in Examples 1-10 above was subjected to an oil displacement test. The simulated well parameters in the oil displacement test were: oil layer porosity of 35.12%, permeability of 143 md, and initial oil saturation of 81.2. The specific process was as follows: the nanoparticle-stabilized foam flooding agent was mixed with oilfield injection water, and then a first injection and a second injection were performed;

[0175] The mass ratio of the nanoparticle-stabilized foam flooding agent to the oilfield injection water in the mixture is 1:500; the amount of the mixed stream injected in the first injection is 0.5PV; the material injected in the second injection is air; and the amount of the material injected in the second injection is 1PV.

[0176] In order to illustrate the effect of the oil-displacing agent of the present invention, the following oil-displacing agents were used as substitutions, as follows:

[0177] Comparative Example 1

[0178] The only difference from Example 1 is that in the oil displacement experiment, 20-50 nm nano-SiO2 particles dispersed in an aqueous solution of sodium dodecylbenzenesulfonate are used as the oil displacement agent.

[0179] Comparative Example 2

[0180] The only difference from Example 1 is that an aqueous solution of sodium dodecylbenzenesulfonate is used as the oil displacement agent in the oil displacement experiment.

[0181] The relevant indicators obtained are detailed in Table 1 below.

[0182] Table 1

[0183]

[0184]

[0185] The results of the above embodiments and comparative examples show that the nanoparticle-stabilized foam oil-displacing agent provided by the present invention achieves a good oil-displacing effect by designing the oil-displacing agent formula and utilizing the synergistic effect between the components. The oil-displacing foam is stable during the oil-displacing process, and a good oil-displacing effect can be achieved, with a significant improvement in oil-displacing efficiency.

[0186] It should be noted that the present invention uses the above-described embodiments to illustrate the detailed structural features of the present invention. However, the present invention is not limited to these detailed structural features, and this does not mean that the present invention must rely on these detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

[0187] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0188] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0189] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A nanoparticle-stabilized foam oil-displacing agent, characterized in that: The nanoparticle-stabilized foam oil-displacing agent comprises: A first surfactant, alcohol, water, an organic solvent, a silicon source precursor, and a second surfactant; The mass ratio of the first surfactant, alcohol and water is (0.2-1):(0.2-1):20; The mass ratio of the organic solvent to the total amount of the first surfactant, alcohol and water is (0.5-5):100; The mass ratio of the silicon source precursor to the total amount of the first surfactant, alcohol, water and organic solvent is (0.1-1):20; The mass ratio of the second surfactant to the total amount of the first surfactant, alcohol, water, organic solvent and silicon source precursor is (0.1-1):

100.

2. The nanoparticle-stabilized foam oil-displacing agent according to claim 1, wherein The first surfactant comprises one or a combination of at least two of di(2-ethylhexyl) sodium sulfosuccinate, nonylphenol polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, sorbitan monolaurate or sodium dodecylbenzenesulfonate; Preferably, the alcohol comprises one or a combination of at least two of n-butanol, isopropanol or ethanol; Preferably, the organic solvent comprises one or a combination of at least two of dichloromethane, chloroform or N,N-dimethylformamide; Preferably, the silicon source precursor comprises one or a combination of at least two of ethyl silicate, phenyltrimethoxysilane, 3-aminopropyltriethoxysilane or vinyltriethoxysilane; Preferably, the second surfactant comprises one or a combination of at least two of sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium bromide, sodium α-olefinsulfonate, sorbitan monooleate or sodium di(2-ethylhexyl)sulfosuccinate.

3. The nanoparticle-stabilized foam oil-displacing agent according to claim 1 or 2, wherein: The first surfactant is one or a combination of at least two of sodium di(2-ethylhexyl)sulfosuccinate and sodium dodecylbenzenesulfonate in a mass ratio of 1:(0.8-1); Preferably, the silicon source precursor is one or a combination of at least two of ethyl silicate, phenyltrimethoxysilane or 3-aminopropyltriethoxysilane; Preferably, the second surfactant is sodium dodecylbenzenesulfonate.

4. A method for preparing a nanoparticle-stabilized foam oil-displacing agent as claimed in any one of claims 1 to 3, characterized in that: The preparation method comprises: Ingredients are proportioned according to mass; performing a first mixing of a first surfactant, alcohol, and water to obtain a first mixed solution; adding an organic solvent to the obtained first mixed solution for second mixing to obtain a second mixed solution; adding a silicon source precursor to the obtained second mixed solution for a third mixing to obtain a third mixed solution; The second surfactant is added to the obtained third mixed liquid to perform a fourth mixing to obtain a nanoparticle-stabilized foam oil-displacing agent.

5. The preparation method according to claim 4, wherein: The stirring speed of the first mixing is 200-800 r / min; Preferably, the first mixing time is 5-20 min; Preferably, the stirring speed of the second mixing is 500-1000 r / min; Preferably, the second mixing time is 15-30 minutes.

6. The preparation method according to claim 4 or 5, characterized in that: The stirring speed of the third mixing is 300-1000 r / min; Preferably, the third mixing time is 3-24h; Preferably, the stirring speed of the fourth mixing is 400-600 r / min; Preferably, the fourth mixing time is 20-35 minutes.

7. A use of the nanoparticle stabilized foam oil-displacing agent according to any one of claims 1 to 3, characterized in that: The application includes: using the nanoparticle-stabilized foam oil-displacing agent to carry out oil displacement.

8. The use according to claim 7, characterized in that The application comprises: mixing the nano-particle stabilized foam oil displacement agent and oil field injection water, and then performing a first injection and a second injection.

9. The use according to claim 8, characterized in that The mass ratio of the nanoparticle-stabilized foam oil-displacing agent to the oilfield injection water in the mixture is 1:(10-1000).

10. The use according to claim 8 or 9, characterized in that The amount of the mixed stream injected in the first injection is 0.2-1PV; Preferably, the material injected in the second injection includes gas; Preferably, the material injected in the second injection includes one or a combination of at least two of nitrogen, air, carbon dioxide or flue gas; Preferably, the amount of the injected material in the second injection is 0.1-2PV.

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