Preparation and application of a nano-imbibition agent for low permeability oil reservoirs

Abstract

The present application provides a nano-sized nano-permeating agent composition that spontaneously forms nanometers, which includes, by mass percentage, 0.5-10% of a biosurfactant, 5-20% of a nonionic surfactant, 5-20% of an amphoteric surfactant, and 3-10% of an inorganic salt. The nano-permeating agent composition provided by the present application can spontaneously form nano-sized micelles. After entering a low-permeability formation, the nano-permeating agent composition will spontaneously reversely permeate and replace crude oil from tiny pores to large pores. The composition described in the present application has a very strong wetting reversal ability, which can transform the reservoir from oil-wetting to water-wetting, thereby improving the recovery rate of crude oil.

Description

Technical Field

[0001] The present application relates to the application field of oilfield chemicals, and in particular to a nano-sized nano-imbibing agent composition that spontaneously forms nano-sizes, and the preparation and application thereof. Background Art

[0002] Energy security is an overall and strategic issue related to the country's economic and social development. It is vital to the country's prosperity and development, the improvement of people's lives, and the long-term stability of society.

[0003] At present, the national oil and gas basins have generally entered the middle and late stages of exploration. With the increasing degree of exploration, the probability of discovering conventional oil and gas reservoirs dominated by structure and lithology is getting lower and lower, and unconventional oil and gas is becoming an important resource type. Low-permeability tight oil and gas resources have accounted for nearly half of my country's total oil and gas resources. As the main new field for the exploration and development of unconventional oil and gas resources in the future, they are mainly distributed in the Junggar Basin, Ordos Basin and Songliao Basin, with a resource reserve of 36.64 billion tons, accounting for 76.9% of the total domestic tight oil resources. Nearly 30.9% of the newly discovered reserves in China belong to low-permeability reservoirs (permeability less than 10×10 -3 μm 2 ). Due to the dense reservoir, narrow pore throat, large fluid flow resistance, and difficulty in replenishing matrix energy, the current low-permeability reservoir development is difficult. For example, the main development strata of a certain oil field are mainly Mesozoic sediments, far away from the hydrocarbon generation center. The strata were deeply buried in the early stage and greatly uplifted and eroded in the later stage. The reservoir energy loss was serious during the diagenetic evolution and accumulation process. The reservoir was shallowly buried and highly heterogeneous. The oil field had a long-term low investment in the early stage and relied on natural energy for exploitation, resulting in "many wells with low production".

[0004] At present, water injection development, hydraulic fracturing, and chemical flooding are the main development methods for tight oil reservoirs. However, the water injection pressure of tight oil reservoirs is high, and development is difficult. Hydraulic fracturing will damage the formation. Chemical flooding (for example, patent publication number CN114774096) is also difficult to enter small pore throats, and general chemical flooding is difficult to achieve good development effects. For low permeability reservoirs, conventional methods for improving oil recovery are difficult to effectively displace the remaining oil therein, while nanomaterials can enter the deep reservoir through small-sized pore throats, give full play to their role in changing rock wettability, reducing interfacial tension, and stripping wall crude oil, thereby improving crude oil recovery efficiency. For example, patent publication number CN115895632 discloses a biological imbibition agent that can change rock wettability to achieve a maximum imbibition recovery rate of 35.52%. The imbibition oil washing rate is an important component of crude oil recovery rate. The improvement of the imbibition oil washing rate helps to improve crude oil recovery rate. Therefore, research on nanomaterials to improve the recovery rate of low permeability reservoirs has great application potential and economic value.

[0005] In the actual mining process, for low permeability oil reservoirs with low porosity (6%-12%), low permeability (0.25mD-2.48mD), low temperature (24℃-65℃), low pressure (0.7), and low oil saturation (38%-53%), it is difficult for the imbibition agents in the existing technology to achieve effective dialysis oil washing. Summary of the invention

[0006] In view of the problems existing in the prior art, the present application provides a nano-sized nano-permeant composition that spontaneously forms, which includes, by mass percentage, 0.5-10% of a biosurfactant, 5-20% of a non-ionic surfactant, 5-20% of an amphoteric surfactant, and 3-10% of an inorganic salt.

[0007] Furthermore, the biosurfactant includes one or more of lipopeptides, glycolipids, and phospholipids.

[0008] Furthermore, the lipopeptide includes one or more of surfactin, iturin, fenmucin, lichenin, babylonin, pamiramycin, sporemycin, and mycosubtilin.

[0009] Furthermore, the glycolipids include one or more of sophorolipids, rhamnolipids, mannosylerythritol lipids, and trehalose lipids.

[0010] Furthermore, the phospholipids include one or more of egg yolk phospholipids, sphingomyelin, hydrogenated soybean lecithin, lecithin, soybean lecithin, and dioleoylphosphatidylcholine.

[0011] Furthermore, the nonionic surfactant includes alkyl glycoside and / or alkanolamide.

[0012] Furthermore, the alkyl glucoside preferably includes glucoside-type alkyl glucoside; further preferably includes one or more of isooctyl glucoside, decyl glucoside, octyl decyl glucoside, coconut glucoside, and lauryl glucoside.

[0013] Furthermore, the alkanolamide preferably includes ethanolamide and / or lauric acid monoisopropanolamide; further preferably, the alkanolamide includes one or more of palm kernel oil diethanolamide, coconut oil diethanolamide, coconut oil monoethanolamide, and stearic acid monoethanolamide.

[0014] Furthermore, the amphoteric surfactant preferably includes a betaine-type amphoteric surfactant; further preferably includes one or more of cocamidopropyl betaine, lauryl hydroxysulfonyl betaine, cocoyl hydroxysulfonyl betaine, cocoyl dimethyl betaine, caprylic decanoyl betaine, oleic acid amide propyl betaine, and lauryl amide propyl betaine.

[0015] Furthermore, the inorganic salt includes one or more of calcium chloride, sodium chloride and magnesium chloride.

[0016] The present application also provides a method for preparing the composition, comprising weighing a biosurfactant, a nonionic surfactant, an amphoteric surfactant and an inorganic salt in proportion;

[0017] The inorganic salt is dissolved, a nonionic surfactant and an amphoteric surfactant are added, heated and stirred, and then a biosurfactant is added and stirred until the mixture is uniformly mixed to obtain a nano-permeating agent composition.

[0018] The present application provides an application of the composition, and the composition is applied to the development of low permeability oil reservoirs.

[0019] The nano-scented agent composition provided in the present application can spontaneously form nano-sized micelles. Capillary force is the main driving force in low-permeability oil reservoirs. After entering the low-permeability formation, the nano-scented agent composition will spontaneously perform reverse scenting to displace crude oil from small pores to large pores. The composition described in the present application has extremely strong wetting reversal ability and can convert the reservoir from oil-wet to water-wet, thereby improving crude oil recovery, especially for low-permeability oil reservoirs with low pore volume and oil saturation, and can achieve a higher crude oil recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the oil absorption and washing rate data of different compositions of the embodiments and comparative examples;

[0021] Figure 2 is the self-priming height of different compositions of the embodiments and comparative examples;

[0022] Figure 3 is the median particle size of the compositions of Examples and Comparative Examples. DETAILED DESCRIPTION

[0023] The specific embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0024] The capillary self-imbibition height refers to the maximum height that the suction force generated by the surface tension of the liquid in the capillary can reach. The present application does not impose any limitation on the method for measuring the capillary self-imbibition height, and any method commonly used in the art can be used as long as the purpose is achieved.

[0025] The present application provides a nano-sized nano-permeating agent composition that spontaneously forms, comprising the following components: a biosurfactant, a nonionic surfactant, an amphoteric surfactant, and an inorganic salt.

[0026] In terms of mass percentage, the ratio of the biosurfactant, the nonionic surfactant, the amphoteric surfactant and the inorganic salt is (0.5-10): (5-20): (5-20): (3-10).

[0027] For example, in terms of mass percentage, the content of the biosurfactant can be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10; the content of the nonionic surfactant can be 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20; the content of the amphoteric surfactant can be 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20; the content of the inorganic salt can be 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10.

[0028] In addition to the above components, the composition also includes water and / or a preservative.

[0029] In some embodiments, during the preparation process, after the above components are weighed, the remainder is water.

[0030] The biosurfactant described in the present application includes one or more of lipopeptides, glycolipids, and phospholipids. For example, lipopeptides, glycolipids, or phospholipids can be selected, or two or three of them can be selected and mixed and added.

[0031] Among them, lipopeptides are a class of amphiphilic substances formed by connecting hydrophilic cyclic oligopeptides and hydrophobic fatty acid chains with lactone bonds. The hydrophilic group in the amphiphilic molecule drives the molecule into water, while the hydrophobic group prevents it from dissolving in water. Under the combined action of the two, a balance is reached, and the excess molecules aggregate to form micelles with the hydrophobic end facing inward and the hydrophilic end facing outward.

[0032] The lipopeptide may be any type of lipopeptide known in the art, for example, from the surfactin family, the iturin family and the fenmustine (also known as fengyuansu) family. In some embodiments, the lipopeptide is selected from any one of surfactin, iturin, fenmustine, lichenin, babylonin, pamilasin, sporemycin, and mycosubtilin, or two or more lipopeptides may be selected and mixed.

[0033] In some embodiments, the lipopeptide is surfactin, iturin, or fenbuconazole.

[0034] The lipopeptide can be produced by bacteria, and the bacteria can be wild bacteria or genetically engineered bacteria, for example, the bacteria can be selected from the following group: Bacillus, Pseudomonas, Streptomyces and Arthrobacter.

[0035] It should be noted that those skilled in the art can understand that the lipopeptide described in the present application can be obtained by commercial purchase or by self-cultivation in the above manner, for example, it can be produced by fermentation of Bacillus subtilis. Taking surfactin as an example, Bacillus subtilis can be directly fermented to obtain a fermentation broth as a product containing surfactin; or further, the pH of the fermentation broth can be adjusted to acidity to precipitate surfactin, and then dried by solid-liquid separation to obtain a product containing surfactin. The above products can all realize the technical solutions described in the present application.

[0036] The present application does not limit the source of glycolipids or phospholipids, as long as the requirements are met. For example, the glycolipid can be selected as any one of sophorolipids, rhamnolipids, mannosylerythritol lipids, trehalose lipids, or a mixture of two or more. For example, the phospholipid can be selected from one or more of egg yolk phospholipids, sphingomyelin, hydrogenated soybean lecithin, lecithin, soybean lecithin, and dioleoylphosphatidylcholine.

[0037] In some embodiments, the glycolipid is a sophorolipid.

[0038] In some embodiments, the glycolipid is a rhamnolipid.

[0039] In some embodiments, the phospholipid is phosphatidylcholine.

[0040] In the present application, the nonionic surfactant may be any type of nonionic surfactant known in the art, for example, an alkyl glycoside or an alkanolamide, or a mixture of an alkyl glycoside and an alkanolamide.

[0041] The alkyl glucoside may be a glucoside type alkyl glucoside, for example, any one of isooctyl glucoside, decyl glucoside, octyl decyl glucoside, coconut glucoside, and lauryl glucoside may be added, or two or more of the glucoside type alkyl glucosides may be arbitrarily selected and mixed for addition.

[0042] In some embodiments, the alkyl glucoside is selected from one of isooctyl glucoside, decyl glucoside, and coconut glucoside.

[0043] The alkanolamide can be ethanolamide, for example, any one of palm kernel oil diethanolamide, coconut oil diethanolamide, coconut oil monoethanolamide, stearic acid monoethanolamide, and lauric acid monoisopropanolamide can be added, or two or more of the above ethanolamides can be mixed and added. In addition to ethanolamide, the alkanolamide can also be lauric acid monoisopropanolamide, or a mixture of lauric acid monoisopropanolamide and ethanolamide.

[0044] In some embodiments, the alkanolamide is selected from palm kernel oil diethanolamide, coconut oil diethanolamide, and lauric acid monoisopropanolamide.

[0045] The nonionic surfactant may be a mixture of alkyl glycoside and alkanolamide, for example, one or more of the above-mentioned ethanolamide or lauric acid monoisopropanolamide and one or more of the above-mentioned alkanolamides, followed by mixing and adding.

[0046] In some embodiments, the nonionic surfactant is a mixture of coco-glucoside and coconut diethanolamide.

[0047] The amphoteric surfactant may be various types of amphoteric surfactants known in the art, for example, betaine-type amphoteric surfactants may be selected from one or more of cocamidopropyl betaine, lauryl hydroxysulfonate, cocoyl hydroxysulfonate, cocoyl dimethyl betaine, caprylic decanoyl betaine, oleic acid amide propyl betaine, and lauryl amide propyl betaine.

[0048] In some embodiments, the amphoteric surfactant is one of cocamidopropyl betaine, lauryl hydroxysulfonate, and lauryl hydroxysulfonate.

[0049] In the present application, the inorganic salt is preferably a metal salt, such as one or more of sodium chloride, magnesium chloride and calcium chloride.

[0050] In some embodiments, the inorganic salt is sodium chloride or magnesium chloride.

[0051] Example

[0052] The experimental methods used in the following examples are all conventional methods unless otherwise specified.

[0053] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0054] Example 1

[0055] Obtaining Biosurfactants

[0056] 1. The biosurfactants in the examples of the present application are obtained by laboratory fermentation, and the lipopeptides are obtained by culturing Bacillus or Bacillus subtilis, including surfactin, iturin, and fenbuconazole.

[0057] 2. The nonionic surfactants and amphoteric surfactants used were purchased from Shandong Yousuo Chemical Technology Co., Ltd.

[0058] Example 2

[0059] Preparation of nano-permeating agent composition

[0060] Weigh the biosurfactant, nonionic surfactant, amphoteric surfactant and inorganic salt according to mass percentage, and the balance is water.

[0061] After dissolving the inorganic salt, a nonionic surfactant and an amphoteric surfactant are sequentially added into a reaction kettle, heated to 30° C. and stirred, and then a biosurfactant is added, and the mixture is continuously stirred until uniformly mixed to obtain a nano-permeating agent composition.

[0062] The types of the components in compositions 1-25 and their corresponding mass percentages are shown in Tables 1-5.

[0063] Compositions 1 to 25 were prepared as 1% aqueous solutions for measurement.

[0064] Example 3

[0065] Evaluation of oil absorption and washing rate of nano-absorbent composition

[0066] 3.1 Saturated core

[0067] 25 artificial average cores with a length of 53.5 mm and a diameter of 25 mm were selected, and the gas permeability was 0.5 mD. The cores were saturated with water and Changqing oil in turn. The pore volume of the obtained cores was about 9.5% to 11.8%, and the oil saturation was 24% to 50%.

[0068] 3.2 Static oil absorption test

[0069] 25 cores were placed in different absorption and washing oil bottles respectively, and 1% aqueous solution of different compositions in Example 2 was added to the absorption bottle to the scale line, and placed in a 45°C environment for 7 days to calculate the absorption and discharge oil volume and the absorption and washing oil rate.

[0070] The oil absorption and washing rate data of different compositions in Example 2 are as follows: Figure 1 shown.

[0071] Example 4

[0072] Capillary self-absorption height test of nano-imbibition agent composition

[0073] 4.1 Preparation of lipophilic capillaries

[0074] 4.1.1 Capillary specifications: The inner diameter of the standard capillary is 0.5 mm. It is treated with carbon tetrachloride, benzene:acetone:ethanol = 7:1.5:1.5 (volume ratio) for 40 min by ultrasonic treatment to remove organic matter on the surface.

[0075] 4.1.2 Then use dilute hydrochloric acid solution (1:10) and hydrofluoric acid solution (10%) to roughen the capillary surface and activate it for 20 minutes, then use deionized water to ultrasonically clean it to remove residual acid until pH>6.5, and then dry it at 105℃.

[0076] 4.1.3 Prepare aging oil according to the proportion, the mass composition of the aging oil is: crude oil: kerosene: 90# asphalt (volume ratio) = 2:5:3, and immerse the treated capillary completely in the aging oil and age it at 60°C for 30 days.

[0077] 4.1.4 Take out the capillary and soak it with kerosene for 2 minutes to clean the asphalt deposited on the inner and outer walls of the capillary, so as not to affect observation. Blow dry the kerosene outside the tube with nitrogen, place it in a closed environment at 60℃ to dry, and obtain the oil-wet capillary, which is stored for future use.

[0078] 4.2 Test sample preparation

[0079] 4.2.1 Prepare 0.3% sample solution with distilled water, keep the solution temperature at 25℃, pour the solution into the cuvette to the top edge, and place the ruler close to the back wall.

[0080] 4.2.2 Place the treated capillary vertically in a cuvette and use a glass slide to keep the capillary at a consistent angle. After 10 minutes, read the height difference between the liquid level in the recording tube and the top edge of the cuvette. Repeat this three times and take the arithmetic mean as the measurement result.

[0081] The self-priming heights of different compositions in Example 2 are as follows: Figure 2 shown.

[0082] Example 5

[0083] Particle size measurement

[0084] The particle size distribution of the nano-permeating agent composition was determined using a laser particle size analyzer. The median particle size of each composition in Example 2 is as follows: Figure 3 shown.

[0085] The particle size (volume distribution) tested in this application is the particle size median, and the particle size median refers to the particle size value D50 corresponding to when the cumulative particle size distribution reaches 50%. For example, if D50 of a sample is 5 μm, it means that the volume of particles larger than 5 μm accounts for 50% of the total volume, and the volume of particles smaller than 5 μm accounts for 50% of the total volume.

[0086] Table 1 Types of biosurfactants

[0087]

[0088] The compositions in Table 1 are selected from different types of biosurfactants, combined with Figure 1-3 It can be seen from the data that the median particle size of the compositions to which different types of biosurfactants are added is all below 100 nm, the oil absorption and washing rates of compositions 2 and 3 are around 25%, the oil absorption and washing rates of the other compositions exceed 30%, and the oil absorption and washing rate of composition 1 is above 40%.

[0089] Table 2 Types of nonionic surfactants

[0090]

[0091]

[0092] The compositions in Table 2 selected different types of nonionic surfactants, combined with Figure 1-3 It can be seen from the data that by adding different types of non-ionic surfactants, including alkanolamide or glucoside type alkyl glycoside or a mixture of alkanolamide and glucoside type alkyl glycoside, the nano-permeating agent composition obtained has a median particle size of less than 80nm, the oil absorption and washing rate of composition 10 is close to 35%, and the oil absorption and washing rates of other compositions are all over 35%, and can reach up to more than 40%.

[0093] Table 3 Types of amphoteric surfactants

[0094]

[0095] The compositions in Table 3 selected different types of amphoteric surfactants, combined with Figure 1-3It can be seen from the data in the table that the nano-permeating agent composition prepared by adding different types of amphoteric surfactants, including a certain amphoteric surfactant or a mixture of two amphoteric surfactants, has a median particle size of less than 80 nm. The oil-washing rate of the composition described in the table is more than 40%.

[0096] Combining the compositions in Tables 2 and 3 and their test data, it can be seen that nonionic surfactants and amphoteric surfactants have a relatively greater impact on the self-imbibition height. Most of the compositions in the embodiments of the present application can reach a self-imbibition height of more than 20 mm, indicating that the nano-imbibition agent prepared in the present application has a strong capillary effect.

[0097] Table 4 Types of inorganic salts

[0098]

[0099] The compositions in Table 4 are composed of different types of inorganic salts. Figure 1-3 It can be seen from the data that the nano-permeating agent compositions prepared by adding different types of inorganic salts have a median particle size of less than 80 nm, and the oil-washing rate of the compositions is more than 35%.

[0100] Table 5 Orthogonal test table of different mass percentage components in Example 2

[0101]

[0102]

[0103] In order to verify the ratio of each component of the nano-permeating agent described in the present application, the orthogonal test table shown in Table 5 was designed. According to the four components described in Example 2, biosurfactant, nonionic surfactant, amphoteric surfactant, and inorganic salt, different addition amounts were selected, including surfactant (addition amount 3%, 6%, 10%), cocoyl glucoside (addition amount 6%, 10%, 20%), cocamidopropyl betaine (addition amount 6%, 10%, 20%), and magnesium chloride (addition amount 3%, 6%, 10%). The orthogonal test table shown in Table 5 was formed according to the above components and ratios, combined with Figure 1-3 It can be seen from the data that the median particle size of each composition in the table is below 80 nm, the oil absorption and washing rates of composition 17 and composition 21 are close to 40%, the oil absorption and washing rates of other compositions are all over 40%, and the oil absorption and washing rate of composition 24 is over 45%.

[0104] The above data show that as long as the addition amount of the four components is within the range described in the present application, that is, the ratio of the biosurfactant, the nonionic surfactant, the amphoteric surfactant, and the inorganic salt is (0.5-10):(5-20):(5-20):(3-10) in mass percentage, the prepared composition can spontaneously form nanosized micelles, improve the oil absorption and washing rate, and thus obtain a higher crude oil recovery rate.

[0105] Comparative Example

[0106] Compositions 26-29 were prepared according to the method described in Examples 1-2, and the oil absorption rate, self-absorption height and particle size of compositions 26-29 were tested according to Examples 3-5. The test data are shown in FIG. Figure 1-3 shown.

[0107] Compared with composition 1, the above compositions are different in that composition 26 does not add a biological surfactant, composition 27 does not add a nonionic surfactant, composition 28 does not add an amphoteric surfactant, and composition 29 does not add an inorganic salt.

[0108] Table 6 Mass ratio of each component of the comparative composition

[0109]

[0110]

[0111] pass Figure 1 It can be seen from the oil absorption and washing rate data of compositions 26-29 that the oil absorption and washing rates of compositions 26, 28 and 29 are all lower than 10%, and the oil absorption and washing rate of composition 27 is less than 15%. In other words, the expected effect cannot be achieved without any one component. Only the composition prepared by using all four components at the same time can achieve a higher oil absorption and washing rate in low permeability cores.

[0112] Figure 3 The data of the particle size of the composition can be seen, lack of amphoteric surfactant, nonionic surfactant or inorganic salt will affect the system particle size, need to exist at the same time to reduce the median particle size to 100nm. Composition 26 lacks biosurfactant, and other components are solutions, and micelles cannot be formed, so there is no data of micelle particle size. That is to say, the nanometer imbibition agent described in the application needs the above four components to be compounded, and can spontaneously form micelles with a median particle size of less than 100nm, while achieving a higher infiltration and absorption oil washing rate, thereby greatly improving crude oil recovery.

[0113] The nano-scentilicate composition provided by the present application can spontaneously form nano-sized micelles. Capillary force is the main driving force in low-permeability oil reservoirs. After entering the low-permeability formation, the nano-scentilicate composition will spontaneously reversely imbibe and displace crude oil from small pores to large pores. The nano-scentilicate composition has a very strong wetting reversal ability and can transform the reservoir from oleophilic to hydrophilic, thereby improving the crude oil recovery rate. The imbibition oil washing rate of the composition is >30% within a wide concentration range.

[0114] The present application optimizes the composition so that it can spontaneously form nanometer size, enter low-permeability pores, and displace crude oil under the action of capillary force.

[0115] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0116] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A nano-permeating agent composition, which comprises, by mass percentage, 0.5-10% of a biosurfactant, 5-20% of a nonionic surfactant, 5-20% of an amphoteric surfactant, and 3-10% of an inorganic salt.

2. The composition according to claim 1, wherein The biosurfactant comprises one or more of lipopeptides, glycolipids and phospholipids.

3. The composition according to claim 2, wherein The lipopeptide comprises one or more of surfactin, iturin, fenmucin, lichenin, babylonin, pamiramycin, sporemycin and mycosubtilin.

4. The composition according to claim 2, wherein The glycolipids include one or more of sophorolipids, rhamnolipids, mannosylerythritol lipids, and trehalose lipids.

5. The composition according to claim 2, wherein The phospholipids include one or more of egg yolk phospholipids, sphingomyelin, hydrogenated soybean lecithin, lecithin, soybean lecithin, and dioleoylphosphatidylcholine.

6. According to the composition of claim 1, the nonionic surfactant comprises an alkyl glucoside and / or an alkanolamide; further preferably, the alkyl glucoside preferably comprises a glucoside-type alkyl glucoside; further preferably, it comprises one or more of isooctyl glucoside, decyl glucoside, octyl decyl glucoside, coconut glucoside, and lauryl glucoside; further preferably, the alkanolamide preferably comprises ethanolamide and / or lauric acid monoisopropanolamide; further preferably, the hexanolamide comprises one or more of palm kernel oil diethanolamide, coconut oil diethanolamide, coconut oil acid monoethanolamide, and stearic acid monoethanolamide.

7. The composition according to claim 1, wherein The amphoteric surfactant preferably includes a betaine-type amphoteric surfactant; further preferably includes one or more of cocamidopropyl betaine, lauryl hydroxysulfonyl betaine, cocoyl hydroxysulfonyl betaine, cocoyl dimethyl betaine, caprylic decanoyl betaine, oleic acid amide propyl betaine, and lauryl amide propyl betaine.

8. The composition according to claim 1, wherein The inorganic salt includes one or more of calcium chloride, sodium chloride and magnesium chloride.

9. A method for preparing the composition according to any one of claims 1 to 8, comprising weighing a biosurfactant, a nonionic surfactant, an amphoteric surfactant and an inorganic salt in proportion; The inorganic salt is dissolved, a nonionic surfactant and an amphoteric surfactant are added, heated and stirred, and then a biosurfactant is added and stirred until the mixture is uniformly mixed to obtain a nano-permeating agent composition.

10. Use of the composition according to any one of claims 1 to 8, wherein the nano-imbibing agent composition is used in the development of low-permeability oil reservoirs.

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