Low permeability reservoir imbibition composition, slickwater fracturing fluid containing the composition and use thereof

Abstract

The application relates to the field of oil reservoir production engineering, and discloses a low-permeability reservoir imbibition composition, slick water fracturing fluid containing the composition and application of the composition. The low-permeability reservoir imbibition composition comprises a surfactant, a polycyclic aromatic compound and a solvent; the surfactant comprises a block polyether surfactant taking a compound with a structure shown in formula (I) as a starter and a C3-C12 alkyl phenol polyoxyethylene ether; R1, R2 and R3 are each C1-C10 alkyl having one or more hydroxyl and / or amino substitutions. The low-permeability reservoir imbibition composition can effectively improve the recovery rate of a low-permeability reservoir, has the characteristics of fast initial imbibition starting, low interfacial tension and complete imbibition, etc. Meanwhile, the composition has good compatibility with a basic system of the slick water fracturing fluid, and has excellent imbibition performance and cleanup performance after gel breaking.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil reservoir production engineering, in particular to a low-permeability reservoir imbibition composition, slick water fracturing fluid containing the composition and application thereof. BACKGROUND

[0002] There are about 6 billion tons of low-permeability oil reservoir reserves in China, of which ultra-low permeability (Class II 1-10 mD, Class III 0.1-1 mD) accounts for more than 58%, and there are more than 300 oil fields. The general recovery rate of low and ultra-low permeability oil fields is 5-28%, with an average of 13.6%. The common problems are low formation pressure, low energy, low permeability, low recovery rate, difficult water injection, and many formation sensitivities. In addition, the continental shale oil resources in China are about 150 billion tons, and the recoverable resources are about 30-60 billion tons. Shale oil has no natural production capacity or commercial exploitation value under natural conditions, and special exploitation techniques such as fracturing are required.

[0003] Low-permeability reservoirs and shale reservoirs are the main objects for further exploitation in the future. The reason why they can be developed is related to the fracture system (natural fractures and fracturing reconstruction) in the reservoir. The matrix rock block plays a role in oil storage, and the fracture plays a role in oil conduction. For fractured low-permeability reservoirs, the main mechanism of oil displacement is to promote the absorption of water in the matrix through imbibition to displace oil and carry out oil production. Therefore, for low-permeability reservoirs and shale reservoirs, the properties of fracturing fluid are the key to pressure displacement and production.

[0004] At present, under the condition of certain reservoir properties and fracturing technology, it is necessary to use fracturing fluid to supplement energy, improve seepage, prevent scaling, and improve water injection efficiency to improve the recovery rate of low-permeability reservoirs and shale oil. Further, from the perspective of fluid dynamics, improve oil and water migration capacity, improve sweep efficiency and oil washing efficiency, improve permeability, let crude oil fully enter the main channel, improve single well production rate, and achieve the purpose of increasing production and improving recovery.

[0005] The conventional chemical enhanced oil recovery (CEOR) focuses on how to mobilize the residual oil and increase the sweep efficiency of the injected liquid, which often requires the injection of surfactant system with ultra-low interfacial tension (<0.001 mN / m) and polymer system with certain viscosity. Therefore, the interfacial tension as the most important parameter for the screening and evaluation of oil displacement agent has been the most concerned index, but how much does it play in the process of imbibition? Zhang et al. (Zhang Y, Feng D S, Zhu Y Y. New methods of theory and experiment for chemical imbibition oil recovery. Beijing: Science Press, 2018, 125.) measured the interfacial tension of 278 groups of imbibition agent systems and studied the oil displacement effect of oil sands by imbibition agent systems with different interfacial tension. From the experimental results, there is no clear functional relationship between the interfacial tension of each imbibition agent system and the imbibition recovery of oil sands, but it can be seen that with the increase of the imbibition recovery of oil sands, the interfacial tension value of the imbibition agent system generally shows a downward trend, that is, in low permeability reservoirs, the imbibition agent system with low interfacial tension is beneficial to the exertion of imbibition, and low interfacial tension has a positive promoting effect on the increase of imbibition recovery. But the interfacial tension value of each imbibition agent system is not much below the ultra-low level of 0.001 mN / m, and the interfacial tension value of most imbibition agent systems with crude oil is greater than 0.1 mN / m. According to the theory that capillary force is the driving force of static imbibition oil recovery, the higher the interfacial tension, the more conducive to the increase of recovery, but the higher interfacial tension weakens the deformation ability of crude oil and reduces the amount of mobile oil, which is not conducive to the increase of imbibition recovery. Therefore, for imbibition oil recovery, there is a reasonable interfacial tension range, which can make the imbibition agent system fully exert the promoting effect of capillary force, and is also conducive to promoting the deformation of crude oil and the mobilization of residual oil in oil-wet parts. At this “balance point” of interfacial tension, imbibition oil recovery can achieve better results.

[0006] The adhesion work can reflect the combination degree of the rock and the crude oil, and is the work that needs to be overcome by the crude oil on the surface of the rock. The greater the adhesion work of the crude oil wetting the rock surface is, the greater the adhesion work is. The adhesion work is related to the interfacial tension of the displacement fluid and the wettability of the rock surface. When the water solution of the imbibition agent acts on the oil on the oil-wet rock surface, if the interfacial tension of the imbibition agent is lower, the contact angle is more likely to be reduced until peeling, and the adhesion work is reduced in this process. In the imbibition agent solution, the crude oil on the rock surface can be started when the crude oil changes from a larger contact angle to a smaller contact angle. Theoretically, the crude oil can be started when the contact angle is reduced to 90°, and the corresponding adhesion work is the theoretical adhesion work of starting the crude oil. In fact, the stable contact angle corresponding to the imbibition agent that can start the crude oil is lower than 90°, and the adhesion work corresponding to the stable contact angle after the action of the imbibition agent is called the actual adhesion work. The difference between the theoretical adhesion work and the actual adhesion work is defined as the adhesion work reduction value. The lower the actual adhesion work value is, the greater the actual work of the imbibition agent is, and the greater the adhesion work reduction value is, the stronger the ability of the imbibition agent to start the oil film is, and the better the imbibition effect is. If the actual adhesion work is greater than the theoretical adhesion work, that is, the adhesion work reduction value is less than 0, it indicates that the crude oil is not started, and the chemical agent or other additives has weak or no ability to start the crude oil.

[0007] slick water, which is a kind of fracturing fluid system for hydraulic fracturing of shale oil and gas reservoirs, is one of the key liquids for shale oil and gas development. 98.0% to 99.5% of the slick water fracturing fluid is sand mixing water, and the additives generally account for 0.5% to 2.0% of the total volume of the slick water, including friction reducers, oil displacement / surfactants, scale inhibitors, clay stabilizers, gel breakers, etc. The friction reducer is the core additive of the slick water fracturing fluid, and acrylamide polymers, polyethylene oxide (PEO), guanidine gum and its derivatives, cellulose derivatives, and viscoelastic surfactants can be used as friction reducers. Compared with the traditional gel fracturing fluid system, the slick water fracturing fluid system is widely used in shale oil and gas development due to its high efficiency and low cost. SUMMARY

[0008] The purpose of the present application is to overcome the problems of low recovery efficiency, high cost and no obvious oil production increase in the fracturing exploitation of low permeability reservoirs. A low permeability reservoir imbibition composition, a slick water fracturing fluid containing the composition and the application thereof are provided, which can effectively reduce the fracturing cost, improve the fracturing stimulation efficiency, improve the overall water injection oil displacement efficiency, and greatly improve the recovery efficiency.

[0009] In order to achieve the above purpose, the first aspect of the present application provides a low permeability layer imbibition composition, which comprises: a surfactant, a polycyclic aromatic compound and a solvent.

[0010] The surface active agent comprises a block polyether surfactant with a compound shown in formula (I) as a starting agent and a C3-C12 alkyl phenol polyoxyethylene ether.

[0011]

[0012] In formula (I), R1, R2 and R3 are each C1-C10 alkyl with one or more hydroxyl and / or amino substitution.

[0013] The second aspect of the present application provides a slick water fracturing fluid containing the low-permeability layer imbibition composition.

[0014] The third aspect of the present application provides application of the low-permeability layer imbibition composition or the slick water fracturing fluid in low-permeability oil reservoirs and shale oil reservoirs.

[0015] Compared with the prior art, the present application has at least the following beneficial effects:

[0016] 1. The low-permeability layer imbibition composition can effectively reduce the fracturing cost and improve the fracturing stimulation efficiency.

[0017] 2. The slick water fracturing fluid containing the low-permeability layer imbibition composition can be recycled and reused after simple treatment to perform single-well plugging removal and stimulation and formation oil displacement.

[0018] 3. The low-permeability layer imbibition composition can improve the overall water injection oil displacement efficiency and greatly improve the recovery rate. DETAILED DESCRIPTION

[0019] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not considered critical for the present application. The endpoints of the ranges and any numerical values are to be understood as approximations. The ranges and numerical values are to be understood to include values approximating these ranges and numerical values. The endpoints of the ranges of values and the individual values are not to be understood as being mutually exclusive, as the scope of the present application includes combinations of these ranges and / or individual values.

[0020] The first aspect of the present application provides a low-permeability layer imbibition composition comprising: a surface active agent, a polycyclic aromatic compound, a solvent.

[0021] The surface active agent comprises a block polyether surfactant with a compound shown in formula (I) as a starting agent and a C3-C10 alkyl phenol polyoxyethylene ether.

[0022]

[0023] R1, R2, R3 are each C1-C10 alkyl having one or more hydroxyl and / or amino substitutions.

[0024] In the present application, the term "alkyl" alone or in combination with other terms includes straight chain or branched chain alkyl. For example, C1-C10 alkyl refers to monovalent alkyl having 1-10 carbon atoms, such as n-propyl, iso-butyl, n-octyl, n-nonyl, etc. It is understood that R1, R2, R3 are each C1-C10 alkyl having one or more hydroxyl and / or amino substitutions refers to a group in which one hydrogen on a monovalent alkyl having 1-10 carbon atoms is replaced by an amino or hydroxyl group, or a group in which multiple hydrogens are replaced by multiple hydroxyl and / or amino groups, the number of substitutions of C1-C10 alkyl being the sum of the number of hydroxyl and amino groups.

[0025] The inventors have found that the composition in the present application can effectively improve the recovery of low permeability reservoirs. The mutual cooperation between the respective components in the composition makes the composition have better wettability, peel force, surface tension, interfacial tension, etc. when used, and has better interpenetration effect on oil, fast peel speed, high efficiency in overcoming adhesion work, high 10 min imbibition height, and high displacement efficiency.

[0026] In some embodiments of the present application, preferably, the low permeability layer imbibition composition comprises, by weight parts, 40-60 parts of surfactant, 6-16 parts of polycyclic aromatic compound, and 19-59 parts of solvent. The use of the foregoing embodiments makes the composition effectively improve the recovery of low permeability reservoirs when used, while having the characteristics of fast initial imbibition start, low interfacial tension, complete imbibition, etc.

[0027] In some embodiments of the present application, the weight ratio of the block polyether surfactant to the C3-C12 alkyl phenol polyoxyethylene ether is (0.5-2):1, for example 0.5:1, 0.6:1, 0.8:1, 1:1, 1.2:1, 1.5:1, or 2:1, preferably (0.6-1.5):1. The use of the foregoing embodiments makes the composition play a role in interfacial stability when used, and can better improve the stability of the oil-water interface.

[0028] In some embodiments of the present application, preferably, in formula (I), R1, R2, R3 are each C1-C5 alkyl having 3-5 hydroxyl and / or amino substitutions. Examples of the starter include triisopropanolamine, triethanolamine, tributanolamine, tris(2-aminoethyl)amine, N,N-bis(2-hydroxyethyl)ethylenediamine, hydroxyethyl diisopropanolamine, etc. The use of the foregoing embodiments makes the composition of the present application have better interpenetration performance when used.

[0029] In some embodiments of the present application, the polyether block of the block polyether surfactant comprises a connection of at least two blocks of ethylene oxide block, propylene oxide block, butylene oxide block and tetrahydrofuran block.

[0030] In some preferred embodiments of the present application, preferably, the polyether block of the block polyether surfactant comprises a connection of at least two blocks of ethylene oxide block, propylene oxide block and butylene oxide block.

[0031] In the present application, the source of the block polyether surfactant is not limited, and those skilled in the art can understand that the block polyether surfactant is prepared by polyaddition reaction of a starter and an epoxy compound (at least two of ethylene oxide, propylene oxide, butylene oxide and tetrahydrofuran) in the presence of a catalyst, and the main chain contains ether bond structure from the epoxy compound, i.e. the polyether block comes from the epoxy compound. For example, when the polyether block of the block polyether surfactant comprises ethylene oxide block and propylene oxide block, it means that the epoxy compound is ethylene oxide and propylene oxide.

[0032] In some embodiments of the present application, the raw materials for preparing the block polyether surfactant comprise, by weight, 0.5-0.7 parts of initiator, 90-110 parts of epoxy compound and 0.1-0.3 parts of catalyst. The type of catalyst is not limited as long as it can achieve polyaddition reaction between the starter and the epoxy compound, and the catalysts that can be listed include KOH, NaOH, sodium methoxide and the like.

[0033] In the present application, the ratio between the at least two of ethylene oxide, propylene oxide, butylene oxide and tetrahydrofuran is not limited, as long as it satisfies the connection of at least two of ethylene oxide block, propylene oxide block, butylene oxide block and tetrahydrofuran block. In some embodiments, the epoxy compound comprises ethylene oxide and propylene oxide, and the weight ratio is (2-4):1; in other embodiments, the epoxy compound comprises ethylene oxide, propylene oxide and butylene oxide, and the weight ratio is (5-7):(0.5-1.5):1.

[0034] In the present application, the preparation method of the block polyether surfactant is not limited, as long as the prepared block polyether surfactant comprises a connection of at least two of ethylene oxide block, propylene oxide block, butylene oxide block and tetrahydrofuran block.

[0035] In some embodiments of the present application, the preparation step of the block polyether surfactant comprises adding the starter and the catalyst into the reactor, and then adding the mixed epoxy compound to react to obtain the block polyether surfactant.

[0036] In the present application, it can be understood that, when using the composition, the corresponding weight parts of the block polyether surfactant component can be taken.

[0037] Specifically, in some embodiments of the present application, the preparation step of the block polyether surfactant comprises: adding a starter and a catalyst into a reactor, then replacing the air in the reactor with nitrogen, heating the reactor to 70-80℃, adding the mixed epoxy compound, and controlling the pressure to be 0.2-0.4 MPa and the temperature to be 140-150℃, after the epoxy compound feeding is completed, continuing to react for 1-5h to obtain the block polyether surfactant.

[0038] In some embodiments of the present application, the polymerization degree of the C3-C12 alkyl phenol polyoxyethylene ether is 20-80, for example, 20, 30, 40, 50, 60, 70 or 80, preferably 40-70.

[0039] In some embodiments of the present application, more preferably, the alkyl group in the C3-C12 alkyl phenol polyoxyethylene ether is a C5-C12 alkyl group; preferably, the alkyl group in the C3-C12 alkyl phenol polyoxyethylene ether is a C8-C10 alkyl group.

[0040] The C3-C12 alkyl phenol polyoxyethylene ether is polymerized from C3-C12 alkyl phenol and ethylene oxide, and in the present application, the C3-C12 alkyl phenol polyoxyethylene ether that can be listed includes butyl phenol polyoxyethylene ether, pentyl phenol polyoxyethylene ether, hexyl phenol polyoxyethylene ether, heptyl phenol polyoxyethylene ether, octyl phenol polyoxyethylene ether, nonyl phenol polyoxyethylene ether, decyl phenol polyoxyethylene ether, undecyl phenol polyoxyethylene ether, dodecyl phenol polyoxyethylene ether, etc.

[0041] In some embodiments of the present application, the C3-C12 alkyl phenol polyoxyethylene ether is selected from one or more of octyl phenol polyoxyethylene ether, nonyl phenol polyoxyethylene ether, decyl phenol polyoxyethylene ether, undecyl phenol polyoxyethylene ether and dodecyl phenol polyoxyethylene ether.

[0042] In some embodiments of the present application, the polyoxyethylene alkyl phenyl ether has a degree of polymerization of 20-80, such as 20, 30, 40, 50, 60, 70 or 80, preferably 40-70. The polyoxyethylene alkyl phenyl ether having a degree of polymerization of 40, such as octyl phenyl polyoxyethylene ether, the polyoxyethylene alkyl phenyl ether having a degree of polymerization of 50, such as octyl phenyl polyoxyethylene ether, the polyoxyethylene alkyl phenyl ether having a degree of polymerization of 60, such as octyl phenyl polyoxyethylene ether, the polyoxyethylene alkyl phenyl ether having a degree of polymerization of 40, such as nonyl phenyl polyoxyethylene ether, the polyoxyethylene alkyl phenyl ether having a degree of polymerization of 50, such as nonyl phenyl polyoxyethylene ether, the polyoxyethylene alkyl phenyl ether having a degree of polymerization of 60, such as nonyl phenyl polyoxyethylene ether, and the like can be listed. With the foregoing embodiments, the mutual synergy between the polyoxyethylene alkyl phenyl ether and the block polyether surfactant can be increased, and the stability, hydration and surface tension adjustment ability of the composition during use can be better improved. Meanwhile, the inventors speculate that it may be because the polyoxyethylene alkyl phenyl ether has a long polyoxyethylene chain, the molecule has strong hydrophilicity, and when the degree of polymerization is 20-80, preferably 40-70, the demulsification of the produced liquid formed by crude oil is rapid when used with the block polyether surfactant, and oil-water separation is facilitated.

[0043] In the present application, the selection of the polycyclic aromatic compound is not limited, and in some embodiments of the present application, the polycyclic aromatic compound includes a fused ring aromatic hydrocarbon compound and / or a fused heterocyclic compound. With the foregoing embodiments, the system action of the block polyether surfactant and the polyoxyethylene alkyl phenyl ether in the composition of the present application can be promoted, and the other components in the composition can be synergized to make the composition clean when used, increase the efficiency of the oil extraction.

[0044] In the present application, the selection of the polycyclic aromatic compound is not limited, and in some embodiments of the present application, the polycyclic aromatic compound includes a fused ring aromatic hydrocarbon compound and / or a fused heterocyclic compound. With the foregoing embodiments, the system action of the block polyether surfactant and the polyoxyethylene alkyl phenyl ether in the composition of the present application can be promoted, and the other components in the composition can be synergized to make the composition clean when used, increase the efficiency of the oil extraction.

[0045] In some embodiments of the present application, preferably, the polycyclic aromatic compound is a fused heterocyclic compound. The use of the foregoing embodiment can better strip the oil, increase the imbibition speed, and the inventors speculate that this is because the interface in the reservoir adsorbs more heavy components due to the change in wettability, and these components are mainly colloid and asphaltene. Colloid is a kind of aromatic heterocyclic compound with a very large molecular weight, generally 500-10000, a carbon-hydrogen ratio of 7-9, and a very complex structure containing carbon, hydrogen, sulfur, oxygen, nitrogen, and other elements. Asphaltene has a structure similar to that of colloid and is more complex than colloid. It is generally considered to be a condensate of colloid, with a larger molecular weight and a carbon-hydrogen ratio of about 10-11. The fused heterocyclic compound in the present application can more easily penetrate into these heavy components at the interface, thereby increasing the stripping of heavy components in the crude oil at the interface.

[0046] In the present application, the type of the solvent is not limited. In some embodiments of the present application, the solvent comprises a benzene-based solvent and / or a polar solvent, and preferably, the solvent comprises a benzene-based solvent and a polar solvent. The use of the foregoing embodiment can not only enable the components with different polarities in the composition to be well miscible together, but also maximize the effective dispersion of the components.

[0047] In the present application, the ratio of the benzene-based solvent and the polar solvent is not limited. In some embodiments of the present application, the weight ratio of the benzene-based solvent to the polar solvent is (0.1-2):1, and preferably (0.2-1.7):1.

[0048] In some embodiments of the present application, the solvent is selected from one or more of benzene, toluene, ethylbenzene, xylene, chlorobenzene, bromobenzene, and propylbenzene.

[0049] In some embodiments of the present application, the polar solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, methanol, ethanol, isopropanol, acetonitrile, dichloromethane, and chloroform.

[0050] The second aspect of the present application provides a slick water fracturing fluid containing the low-permeability layer imbibition composition of the present application. Preferably, in the slick water fracturing fluid, the content of the low-permeability layer imbibition composition is 0.05-1 wt%, for example, 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.8 wt%, 0.9 wt%, or 1 wt%, and preferably 0.1-0.5 wt%.

[0051] In the present application, slick water fracturing fluid is a fracturing fluid system for hydraulic fracturing of shale oil and gas reservoirs, and is one of the key liquids for shale oil and gas development. In some embodiments, 98.0-99.5wt% of the slick water fracturing fluid is sand mixing water, and the additives generally account for 0.5-2.0% of the total mass of the slick water, including emulsion drag-reducing agents, high-efficiency oil displacement surfactants, scale inhibitors, clay stabilizers, gel breakers, etc. The specific composition is not limited and can be selected as needed.

[0052] When using the low-permeability layer imbibition composition of the present application, each corresponding combination in the low-permeability layer imbibition composition can be added to the basic system of the slick water fracturing fluid, and the order of addition of each combination is not limited, or each combination of the low-permeability layer imbibition composition can be mixed uniformly and then added to the basic system of the slick water fracturing fluid.

[0053] The third aspect of the present application provides the use of the low-permeability layer imbibition composition of the present application or the slick water fracturing fluid of the present application in low-permeability oil reservoirs and shale oil reservoirs.

[0054] The present application will be described in detail below by way of examples. In the following examples and comparative examples, unless otherwise specified, the reagents used in the following examples and comparative examples can be obtained commercially.

[0055] In the following examples and comparative examples:

[0056] The nonylphenol polyoxyethylene ether with a polymerization degree of 50 of ethylene oxide is a commercially available product with a brand of NP-50;

[0057] The octylphenol polyoxyethylene ether with a polymerization degree of 40 of ethylene oxide is a commercially available product with a brand of OP-40;

[0058] The nonylphenol polyoxyethylene ether with a polymerization degree of 40 of ethylene oxide is a commercially available product with a brand of NP-50;

[0059] The nonylphenol polyoxyethylene ether with a polymerization degree of 15 of ethylene oxide is a commercially available product with a brand of NP-15.

[0060] In the following examples and comparative examples, the test methods are as follows:

[0061] The slick water fracturing fluid basic system was prepared according to the formulation in Table 1. The raw materials in Table 1, Nos. 1-4, were all produced by Sinopec Landshore Company:

[0062] Table 1

[0063] Serial No. Formulation Addition amount 1 Emulsion friction reducer of type SFFR 0.3wt% 2 High efficiency cleanup additive of type SFCU 0.1wt% 3 Clay stabilizer of type SFCS 0.3wt% 4 Breaker of type SFCP 0.03wt% 5 Water 99.27wt%

[0064] Preparation method: after mixing Nos. 1-3 and 5, 4 was added, and the gel was broken at 90°C for 1 hour, and then cooled to room temperature to obtain the slick water fracturing fluid basic system.

[0065] Preparation of slick water fracturing fluid: add the sample with content of 0.1% of the mass of the slick water fracturing fluid to the slick water fracturing fluid basic system to obtain the slick water fracturing fluid.

[0066] 1. Compatibility of imbibition agent with slick water fracturing fluid system

[0067] According to the formula in Table 1, the addition amount of serial numbers 1-4 is expanded by 10 times, the rest is supplemented to 100wt% with water to configure the slick water fracturing fluid system-1, add the sample with content of 1% of the mass of the slick water fracturing fluid basic system to the slick water fracturing fluid basic system-1 to obtain the slick water fracturing fluid-1, the slick water fracturing fluid-1 has no stratification, no precipitation, no turbidity, no discoloration, recorded as good, otherwise poor.

[0068] 2. Interfacial tension test

[0069] The surface tension value refers to the "liquid-gas" surface tension value formed by the sample (or slick water fracturing fluid) and air; the interfacial tension refers to the "liquid-liquid" interfacial tension value formed by the sample (or slick water fracturing fluid) and dehydrated 3# aviation kerosene;

[0070] Test method ("hanging drop method"): weigh 0.6000g of the sample (or slick water fracturing fluid) into a 200mL clean volumetric flask, dilute to the mark with deionized water to prepare a 0.3wt% solution, then use the surface and interfacial tension instrument to test the surface tension and interfacial tension values at 25°C.

[0071] 3. Capillary imbibition test

[0072] Preparation of oil-wet capillary: (1) organic matter removal: under ultrasonic conditions, wash the standard capillary with inner diameter of 0.3mm with chromic acid solution; (2) roughening and activation treatment: use the mixture of hydrochloric acid and water with volume ratio of 1:9, and 10% hydrofluoric acid solution to roughen and activate the standard capillary after organic matter removal for 30min; (3) water washing: under ultrasonic conditions, wash the roughened and activated standard capillary with deionized water until pH>6.5; (4) first drying: 105°C drying; (4) aging: immerse the dried standard capillary in the aging oil prepared by 2:5:3 of crude oil: 3# aviation kerosene: 90# asphalt by mass ratio at 60°C for 4 weeks; (5) cleaning: use kerosene to clean the asphalt on the outer wall of the aged standard capillary; (6) second drying: dry the cleaned standard capillary at 60°C to obtain the oil-wet capillary.

[0073] 10 min imbibition height test method: 0.3% of the test solution (sample or slick water fracturing fluid in water) is prepared with deionized water, the temperature of the test solution is kept at 25°C, the test solution is poured into a colorimetric tube, and a ruler is placed vertically behind the back wall. The treated oil-wet capillary tube is placed vertically in the colorimetric tube, and the liquid level height is read and recorded. The liquid level height at 10 min is recorded

[0074] 4. Test of flowback rate

[0075] Test method: In the existing flowback rate test device, 20-40 mesh quartz sand is used to fill the pipe to simulate the test of flowback rate. The 20-40 mesh quartz sand is filled into a sand filling pipe with a length of 25 cm and a diameter of 2.5 cm, and shaken up and down 200 times to make the permeability basically consistent each time. At room temperature, the slick water fracturing fluid (0.5wt% of the amount of quartz sand) is injected into the sand filling pipe, and then the breaker of SFCP type (0.03wt% of the amount of quartz sand) is injected into the sand filling pipe. The lower valve is opened to make the liquid flow out under the action of gravity, and the amount of effluent is recorded to calculate the flowback rate (flowback rate = effluent amount / injected mixed liquid amount*100%); the blank control group uses water instead of the slick water fracturing fluid.

[0076] Example 1

[0077] The low-permeability layer imbibition composition of the present embodiment includes, by weight, 20 parts of block polyether surfactant, 30 parts of nonylphenol polyoxyethylene ether with a polymerization degree of 50 of ethylene oxide, 3 parts of quinoline, 8 parts of fluorene, 10 parts of toluene, and 29 parts of N,N-dimethylformamide.

[0078] The block polyether surfactant is a polyether block of block polyether surfactant with triisopropanolamine as a starter; the polyether block of the block polyether surfactant includes a connection of ethylene oxide block and propylene oxide block; the raw materials of the block polyether surfactant include, by weight, 0.5 parts of triisopropanolamine, 70 parts of ethylene oxide, 30 parts of propylene oxide, and 0.2 parts of catalyst (KOH), and the preparation method includes: ethylene oxide and propylene oxide are respectively added to 1# and 2# tanks, and after being measured at a certain ratio, they are put into 3# tank; triisopropanolamine and KOH are added to a dry high-pressure reaction kettle, the high-pressure reaction kettle is assembled, the air in the kettle is replaced with nitrogen for 3-5 times, the device pipeline is purged, then heating is performed, when the temperature in the kettle rises to 75°C, the mixed mixture of measured ethylene oxide and propylene oxide is added, the pressure is controlled at 0.2 MPa, and the temperature is controlled at 150°C, after the feeding is completed, the reaction is continued for 3 hours. Then, the temperature is lowered, the residual gas in the pipeline and the reaction kettle is purged with nitrogen, and the block polyether surfactant is obtained.

[0079] After the components of the low-permeability layer imbibition composition are mixed uniformly, they are used as a sample.

[0080] The surface tension, interfacial tension, 10 min liquid level height test results of the sample of this example are shown in Table 2.

[0081] The surface tension, interfacial tension, 10 min liquid level height test results of slick water fracturing fluid configured by using the sample of this example, and the flowback rate, compatibility of the sample with the basic system of the slick water fracturing fluid are shown in Table 3.

[0082] Example 2

[0083] The low-permeability layer imbibition composition of this example comprises, by weight parts, 25 parts of block polyether surfactant, 25 parts of nonylphenol polyoxyethylene ether with a polymerization degree of 50 of ethylene oxide, 5 parts of quinoline, 5 parts of fluorene, 12 parts of toluene, and 28 parts of N,N-dimethylformamide.

[0084] The polyether block of the block polyether surfactant is a polyether block of a block polyether surfactant with triisopropanolamine as a starter; the polyether block of the block polyether surfactant comprises a connection of an ethylene oxide block and a propylene oxide block; the raw materials of the block polyether surfactant comprise, by weight parts, 0.6 parts of triisopropanolamine, 80 parts of ethylene oxide, 20 parts of propylene oxide, and 0.2 parts of a catalyst (KOH), and the preparation method comprises: ethylene oxide and propylene oxide are respectively added to 1# and 2# tanks, and after being measured at a certain ratio, they are added to 3# tank; triisopropanolamine and KOH are added to a dry high-pressure reaction kettle, the high-pressure reaction kettle is assembled, the air in the kettle is replaced with nitrogen for 3-5 times, the device pipeline is purged, then heating is performed, when the temperature in the kettle rises to 70°C, the mixture of the measured ethylene oxide and propylene oxide is added, the pressure is controlled at 0.3 MPa, and the temperature is controlled at 145°C, after the feeding is completed, the reaction is continued for 3 hours. Then, the temperature is lowered, the residual gas in the pipeline and the reaction kettle is purged with nitrogen, and the block polyether surfactant is obtained.

[0085] After the components of the low-permeability layer imbibition composition are uniformly mixed, the mixture is used as a sample.

[0086] The surface tension, interfacial tension, 10 min liquid level height test results of the sample of this example are shown in Table 2.

[0087] The surface tension, interfacial tension, 10 min liquid level height test results of slick water fracturing fluid configured by using the sample of this example, and the flowback rate, compatibility of the sample with the basic system of the slick water fracturing fluid are shown in Table 3.

[0088] Example 3

[0089] The low-permeability layer imbibition composition of the embodiment comprises, by weight parts, 30 parts of block polyether surfactant, 20 parts of nonylphenol polyoxyethylene ether with a polymerization degree of 50 of ethylene oxide, 8 parts of quinoline, 8 parts of fluorene, 15 parts of toluene, and 19 parts of N,N-dimethylformamide;

[0090] The polyether block of the block polyether surfactant is a polyether block of a block polyether surfactant with triisopropanolamine as a starting agent; the polyether block of the block polyether surfactant comprises a connection of an ethylene oxide block and a propylene oxide block; raw materials of the block polyether surfactant comprise, by weight parts, 0.7 parts of triisopropanolamine, 75 parts of ethylene oxide, 25 parts of propylene oxide, and 0.2 parts of a catalyst (KOH); and a preparation method thereof comprises: ethylene oxide and propylene oxide are respectively added to 1# and 2# tanks, and after being measured at a certain ratio, the ethylene oxide and the propylene oxide are added to 3# tank; triisopropanolamine and KOH are added to a dry high-pressure reaction kettle, the high-pressure reaction kettle is assembled, the air in the kettle is replaced with nitrogen for 3-5 times, the device pipeline is purged, then heating is performed, when the temperature in the kettle rises to 75°C, the mixture of the measured ethylene oxide and propylene oxide is added, the pressure is controlled at 0.5 MPa, and the temperature is controlled at 140°C; after the feeding is completed, the reaction is continued for 3 hours; then the temperature is lowered, the residual gas in the pipeline and the reaction kettle is purged with nitrogen, and the block polyether surfactant is obtained.

[0091] After the components of the low-permeability layer imbibition composition are uniformly mixed, the mixture is used as a sample.

[0092] As shown in Table 2, the test results of the surface tension, the interfacial tension, and the 10 min liquid level height of the sample of the embodiment are shown in Table 2.

[0093] As shown in Table 3, the test results of the surface tension, the interfacial tension, and the 10 min liquid level height of the slick water fracturing fluid configured by using the sample of the embodiment, and the flowback rate and the compatibility of the sample with the basic system of the slick water fracturing fluid are shown in Table 3.

[0094] Embodiment 4

[0095] The low-permeability layer imbibition composition of the embodiment comprises, by weight parts, 30 parts of block polyether surfactant, 20 parts of nonylphenol polyoxyethylene ether with a polymerization degree of 50 of ethylene oxide, 8 parts of quinoline, 8 parts of fluorene, 15 parts of toluene, and 19 parts of N,N-dimethylformamide;

[0096] The polyether block of the block polyether surfactant is a polyether block of a block polyether surfactant with triethanolamine as a starting agent; the polyether block of the block polyether surfactant comprises a connection of an ethylene oxide block and a propylene oxide block; raw materials of the block polyether surfactant comprise, by weight parts, triethanolamine 0.5 parts, ethylene oxide 80 parts, propylene oxide 20 parts, and a catalyst (KOH) 0.2 parts; and a preparation method thereof comprises: ethylene oxide and propylene oxide are respectively added into 1# and 2# tanks, and after being measured according to a certain proportion, the ethylene oxide and the propylene oxide are added into 3# tank; triisopropanolamine and KOH are added into a dry high-pressure reaction kettle, the high-pressure reaction kettle is assembled, the air in the kettle is replaced with nitrogen for 3-5 times, the device pipeline is purged, then heating is performed, when the temperature in the kettle rises to 75 ℃, the mixture of the measured ethylene oxide and propylene oxide is added, the pressure is controlled at 0.5 MPa, and the temperature is controlled at 140 ℃; after the feeding is completed, the reaction is continued for 3 hours; then the temperature is lowered, the residual gas in the pipeline and the reaction kettle is purged with nitrogen, and the block polyether surfactant is obtained.

[0097] After the components of the low-permeability layer imbibition composition are uniformly mixed, the low-permeability layer imbibition composition is used as a sample.

[0098] As shown in Table 2, the test results of the surface tension, the interfacial tension, and the 10 min liquid level height of the sample of this example are shown.

[0099] As shown in Table 3, the test results of the surface tension, the interfacial tension, the 10 min liquid level height, the flowback rate, and the compatibility of the slick water fracturing fluid basic system of the sample configured using the sample of this example are shown.

[0100] Example 5

[0101] According to the method of Example 4, except that:

[0102] The low-permeability layer imbibition composition comprises, by weight parts, block polyether surfactant 25 parts, nonylphenol polyoxyethylene ether with a polymerization degree of 50 of ethylene oxide 25 parts, quinoline 5 parts, fluorene 5 parts, toluene 12 parts, and N,N-dimethylformamide 28 parts.

[0103] The raw materials of the block polyether surfactant comprise, by weight parts, triethanolamine 0.6 parts, ethylene oxide 75 parts, propylene oxide 25 parts, and a catalyst (KOH) 0.2 parts.

[0104] After the components of the low-permeability layer imbibition composition are uniformly mixed, the low-permeability layer imbibition composition is used as a sample.

[0105] As shown in Table 2, the test results of the surface tension, the interfacial tension, and the 10 min liquid level height of the sample of this example are shown.

[0106] As shown in Table 3: the surface tension, interfacial tension, 10 min liquid level test value of slick water fracturing fluid configured for the sample of the use example, and the test results of the compatibility of the sample with the basic system of the slick water fracturing fluid.

[0107] Example 6

[0108] According to the method of Example 4, except that:

[0109] The low-permeability layer imbibition composition comprises, by weight part, 30 parts of block polyether surfactant, 30 parts of nonylphenol polyoxyethylene ether with a polymerization degree of 50 of ethylene oxide, 8 parts of quinoline, 8 parts of fluorene, 15 parts of toluene, and 9 parts of N,N-dimethylformamide.

[0110] The raw material of the block polyether surfactant comprises, by weight part, 0.7 parts of triethanolamine, 70 parts of ethylene oxide, 30 parts of propylene oxide, and 0.2 parts of catalyst (KOH).

[0111] After the components of the low-permeability layer imbibition composition are uniformly mixed, the mixture is used as a sample.

[0112] As shown in Table 2: the test results of the surface tension, interfacial tension, and 10 min liquid level of the sample of the example;

[0113] As shown in Table 3: the surface tension, interfacial tension, 10 min liquid level test value of slick water fracturing fluid configured for the sample of the use example, and the test results of the compatibility of the sample with the basic system of the slick water fracturing fluid.

[0114] Example 7

[0115] According to the method of Example 3, except that:

[0116] The nonylphenol polyoxyethylene ether with a polymerization degree of 50 of ethylene oxide is replaced by octylphenol polyoxyethylene ether with a polymerization degree of 40 of ethylene oxide; and the fluorene is replaced by naphthalene.

[0117] The polyether block of the block polyether surfactant comprises the connection of an ethylene oxide block, a propylene oxide block, and a butylene oxide block; the raw materials of the block polyether surfactant comprise, by weight parts, triisopropanolamine 0.7 parts, ethylene oxide 75 parts, propylene oxide 12.5 parts, butylene oxide 12.5 parts; a catalyst (KOH) 0.3 parts, and the preparation method comprises the following steps: ethylene oxide, propylene oxide, and butylene oxide are respectively added into 1#, 2#, and 3# tanks, and then are measured at a certain ratio and then are added into 4# tank; triisopropanolamine and KOH are added into a dry high-pressure reaction kettle, the high-pressure reaction kettle is assembled, the air in the kettle is replaced by nitrogen for 3-5 times, the device pipeline is purged, then heating is performed, when the temperature in the kettle rises to 75℃, the mixture of the measured ethylene oxide, propylene oxide, and butylene oxide is added, the pressure is controlled at 0.5 MPa, the temperature is controlled at 150℃, after the feeding is completed, the reaction is continuously performed for 3 hours, then the temperature is lowered, the residual gas in the pipeline and the reaction kettle is purged by nitrogen, and the block polyether surfactant is obtained.

[0118] After the components of the low-permeable layer imbibition composition are uniformly mixed, the mixture is used as a sample.

[0119] As shown in Table 2, the test results of the surface tension, the interfacial tension, and the 10 min liquid level height of the sample of this example are shown in Table 2;

[0120] As shown in Table 3, the test results of the surface tension, the interfacial tension, and the 10 min liquid level height of the slick water fracturing fluid configured by using the sample of this example, and the flowback rate and the compatibility of the sample with the basic system of the slick water fracturing fluid are shown in Table 3.

[0121] Example 8

[0122] According to the method of Example 1, except that:

[0123] The nonylphenol polyoxyethylene ether with a polymerization degree of 40 of ethylene oxide is used to replace the nonylphenol polyoxyethylene ether with a polymerization degree of 50 of ethylene oxide; indole is used to replace quinoline; dimethyl sulfoxide is used to replace N,N-dimethylformamide;

[0124] The polyether block surfactant is a polyether block of a block polyether surfactant with tri(2-aminoethyl)amine as a starting agent; the polyether block of the block polyether surfactant comprises a connection of an ethylene oxide block and a propylene oxide block; the raw materials of the block polyether surfactant comprise, by weight parts, tri(2-aminoethyl)amine 0.5 parts, ethylene oxide 70 parts, propylene oxide 30 parts, catalyst (KOH) 0.2 parts, and the preparation method comprises the following steps: ethylene oxide and propylene oxide are respectively added into 1# and 2# tanks, and after being measured according to a certain proportion, the mixture is added into 3# tank; tri(2-aminoethyl)amine and KOH are added into a dry high-pressure reaction kettle, the high-pressure reaction kettle is assembled, the air in the kettle is replaced with nitrogen for 3-5 times, the device pipeline is purged, then heating is performed, when the temperature in the kettle rises to 75 ℃, the mixture of the measured ethylene oxide and propylene oxide is added, the pressure is controlled at 0.2 MPa, and the temperature is controlled at 150 ℃; after the feeding is completed, the reaction is continued for 3 hours; then the temperature is lowered, the residual gas in the pipeline and the reaction kettle is purged with nitrogen, and the block polyether surfactant is obtained.

[0125] After the components of the low-permeability layer imbibition composition are uniformly mixed, the mixture is used as a sample.

[0126] As shown in Table 2, the test results of the surface tension, the interfacial tension, and the 10 min liquid level of the sample of this example are shown.

[0127] As shown in Table 3, the test results of the surface tension, the interfacial tension, the 10 min liquid level, the flowback rate, and the compatibility of the sample with a slick water fracturing fluid basic system of the slick water fracturing fluid configured using the sample of this example are shown.

[0128] Example 9

[0129] According to the method of Example 1, the difference is that:

[0130] The low-permeability layer imbibition composition of this example comprises, by weight parts, block polyether surfactant 20 parts, nonylphenol polyoxyethylene ether with a degree of polymerization of ethylene oxide of 50 30 parts, quinoline 3 parts, fluorene 8 parts, and toluene 39 parts.

[0131] After the components of the low-permeability layer imbibition composition are uniformly mixed, the mixture is used as a sample.

[0132] As shown in Table 2, the test results of the surface tension, the interfacial tension, and the 10 min liquid level of the sample of this example are shown.

[0133] As shown in Table 3, the test results of the surface tension, the interfacial tension, the 10 min liquid level, the flowback rate, and the compatibility of the sample with a slick water fracturing fluid basic system of the slick water fracturing fluid configured using the sample of this example are shown.

[0134] Example 10

[0135] The method of Example 1 was followed, except that:

[0136] The low permeation layer imbibing composition included, by weight parts, block polyether surfactant 20 parts, nonylphenol polyoxyethylene ether with a degree of polymerization of ethylene oxide of 50 30 parts, quinoline 3 parts, fluorene 8 parts, N,N-dimethylformamide 39 parts.

[0137] The components of the low permeation layer imbibing composition were mixed uniformly to serve as a sample.

[0138] As shown in Table 2: the test results of the surface tension, interfacial tension, 10 min liquid level height of the sample of this example;

[0139] As shown in Table 3: the test results of the surface tension, interfacial tension, 10 min liquid level height of the slick water fracturing fluid configured using the sample of this example, and the flowback rate, compatibility of the sample with the slick water fracturing fluid base system.

[0140] Example 11

[0141] The method of Example 1 was followed, except that:

[0142] Nonylphenol polyoxyethylene ether with a degree of polymerization of ethylene oxide of 15 was used instead of nonylphenol polyoxyethylene ether with a degree of polymerization of ethylene oxide of 50.

[0143] Example 12

[0144] The method of Example 1 was followed, except that:

[0145] The polyether block of the block polyether surfactant included the connection of an ethylene oxide block and a tetrahydrofuran block, and tetrahydrofuran was used instead of propylene oxide.

[0146] Comparative Example 1

[0147] The method of Example 1 was followed, except that:

[0148] The low permeation layer imbibing composition included, by weight parts, block polyether surfactant 20 parts, nonylphenol polyoxyethylene ether with a degree of polymerization of ethylene oxide of 50 30 parts, N,N-dimethylformamide 50 parts.

[0149] The components of the low permeation layer imbibing composition were mixed uniformly to serve as a sample.

[0150] As shown in Table 2: the test results of the surface tension, interfacial tension, 10 min liquid level height of the sample of this example;

[0151] As shown in Table 3: the surface tension, interfacial tension, 10 min liquid level test value of slick water fracturing fluid configured for the sample of the example, and the test results of flowback rate, compatibility of the sample with the basic system of slick water fracturing fluid.

[0152] Comparative Example 2

[0153] According to the method of Example 1, except that:

[0154] The nano oil displacement surfactant SFCN (produced by Sinopec Continental Shelf Company) is used to replace the block polyether surfactant.

[0155] After the components of the low permeability layer imbibition composition are uniformly mixed, they are used as samples.

[0156] As shown in Table 2: the surface tension, interfacial tension, 10 min liquid level test results of the sample of the example;

[0157] As shown in Table 3: the surface tension, interfacial tension, 10 min liquid level test value of slick water fracturing fluid configured for the sample of the example, and the test results of flowback rate, compatibility of the sample with the basic system of slick water fracturing fluid.

[0158] Comparative Example 3

[0159] According to the method of Example 1, except that:

[0160] The low permeability layer imbibition composition includes, by weight, 50 parts of block polyether surfactant, 3 parts of quinoline, 8 parts of fluorene, 10 parts of toluene, and 29 parts of N,N-dimethylformamide.

[0161] As shown in Table 1: the surface tension, interfacial tension, 10 min liquid level test results of the sample of the example in the water system;

[0162] As shown in Table 2: the surface tension, interfacial tension, 10 min liquid level test value of the sample of the example in the slick water fracturing fluid system, and the test results of flowback rate, compatibility of the sample with the slick water fracturing fluid system.

[0163] Comparative Example 4

[0164] According to the method of Example 1, except that:

[0165] The low permeability layer imbibition composition includes, by weight, 50 parts of nonylphenol polyoxyethylene ether with a polymerization degree of 50 of ethylene oxide, 3 parts of quinoline, 8 parts of fluorene, 10 parts of toluene, and 29 parts of N,N-dimethylformamide.

[0166] As shown in Table 1: the surface tension, interfacial tension, liquid level height test results of the sample of this example under water system;

[0167] As shown in Table 2: the surface tension, interfacial tension, liquid level height test values of the sample of this example under slick water fracturing fluid system, and the test results of flowback rate, compatibility of the sample with the slick water fracturing fluid system.

[0168] Table 2

[0169]

[0170] As can be seen from the results in Table 2, due to the adsorption of oil and capillary wall, pure water is difficult to overcome the adsorption work to drive oil, that is, no obvious wicking occurs, while the low permeation layer wicking composition of embodiments 1-10 of the present application can reduce the interfacial tension of the system, and also can increase the 10 min wicking height, and has good wicking effect. The surfactant (block polyether surfactant and C3-C12 alkyl phenol polyoxyethylene ether) in the low permeation layer wicking composition plays a very important role, directly affects the 10 min wicking height, and the block polyether surfactant has particularly important effect on permeation. The polycyclic aromatic compound and the solvent can further improve the wicking effect of the composition.

[0171] Table 3

[0172]

[0173]

[0174] As can be seen from the results in Table 3, the low permeation layer wicking composition of the present application is basically compatible with the slick water fracturing fluid basic system, without stratification, precipitation, turbidity, discoloration, and the slick water fracturing fluid obtained by mixing the low permeation layer wicking composition and the slick water fracturing fluid basic system has relatively low surface tension and interfacial tension. The composition still overcomes the adsorption work to drive oil in the slick water fracturing fluid basic system, and has good wicking effect.

[0175] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application, and all fall within the protection scope of the present application.

Claims

1. A low-osmolar layer by layer composition, characterized in that, The low-permeability layer imbibition composition comprises: a surfactant, a polycyclic aromatic compound, a solvent; The surfactant comprises a block polyether surfactant and a C3-C12 alkyl phenol polyoxyethylene ether; The low-permeability layer imbibition composition comprises, by weight, 40-60 parts of surfactant, 6-16 parts of polycyclic aromatic compound, and 19-59 parts of solvent; The initiator of the block polyether surfactant comprises one of triisopropanolamine, triethanolamine, tributanolamine, tris(2-aminoethyl)amine, and hydroxyethyl diisopropanolamine; The polyether block of the block polyether surfactant comprises a connection of at least two blocks of an oxirane block, a propylene oxide block, and a butylene oxide block, and the polyether block is derived from an epoxide compound; The alkyl group in the C3-C12 alkyl phenol polyoxyethylene ether is a C8-C12 alkyl group; The polymerization degree of the oxirane in the C3-C12 alkyl phenol polyoxyethylene ether is 20-80; The polycyclic aromatic compound comprises a fused ring aromatic hydrocarbon compound and / or a fused heterocyclic compound; The fused ring aromatic hydrocarbon compound is naphthalene; The fused heterocyclic compound is quinoline and / or fluorene; The solvent comprises a benzene-based solvent and / or a polar solvent; The weight ratio of the block polyether surfactant to the C3-C12 alkyl phenol polyoxyethylene ether is (0.5-2):

1.

2. The low-permeability layer imbibition composition of claim 1, wherein the weight ratio of the block polyether surfactant to the C3-C12 alkyl phenol polyoxyethylene ether is (0.6-1.5):

1.

3. The low-osmolar layer-by-layer composition of claim 1, wherein, The epoxide compound comprises oxirane, propylene oxide, and butylene oxide, and the weight ratio is (5-7):(0.5-1.5):1; and / or The alkyl group in the C3-C12 alkyl phenol polyoxyethylene ether is a C5-C12 alkyl group; and / or The polymerization degree of the oxirane in the C3-C12 alkyl phenol polyoxyethylene ether is 40-70.

4. The low-osmolar layer-by-layer composition of claim 1 or 3, wherein, The epoxide compound comprises oxirane and propylene oxide, and the weight ratio is (2-4):

1.

5. The low-osmolar layer-by-layer composition of claim 1, wherein, The C3-C12 alkyl phenol polyoxyethylene ether is selected from one or more of octyl phenol polyoxyethylene ether, nonyl phenol polyoxyethylene ether, decyl phenol polyoxyethylene ether, undecyl phenol polyoxyethylene ether, and dodecyl phenol polyoxyethylene ether.

6. The low-osmolar layer-by-layer composition of claim 1, wherein, The solvent comprises a benzene-based solvent and a polar solvent.

7. The low-permeability layer imbibition composition of claim 6, wherein, The weight ratio of the benzene-based solvent to the polar solvent is (0.1-2):1; and / or The benzene-based solvent is selected from one or more of benzene, toluene, ethylbenzene, xylene, chlorobenzene, bromobenzene, and propylbenzene; and / or The polar solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, methanol, ethanol, isopropanol, acetonitrile, dichloromethane, and chloroform.

8. The low-osmolar layer-by-layer composition of claim 6 or 7, wherein, The weight ratio of the benzene-based solvent to the polar solvent is (0.2-1.7).

9. A slickwater fracturing fluid characterized by, The slick water fracturing fluid contains the low-permeability layer imbibition composition of any one of claims 1-8.

10. The slick water fracturing fluid of claim 9, wherein, In the slick water fracturing fluid, the content of the low-permeability layer imbibition composition is 0.05-1 wt%.

11. The slickwater fracturing fluid of claim 9 or 10, wherein, The low-permeability layer imbibition composition is contained in the slick water fracturing fluid in an amount of 0.1-0.5 wt%.

12. Use of the low-permeability layer imbibition composition according to any one of claims 1-8 or the slick water fracturing fluid according to any one of claims 9-11 in low-permeability oil reservoirs and shale oil reservoirs.

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