A method and composition for preparing water-based modified nanomaterials

Abstract

The present invention provides a method and composition for preparing a water-based modified nanomaterial. The composition comprises the water-based modified nanomaterial prepared by the method, a second surfactant, and an additive, and is a nano-permeant. At room temperature, the composition improves gas well production by 22.29% to 34.56% and oil well production by 13.46% to 39.58%, improving both gas and oil well production.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic fracturing production enhancement and modification, and in particular relates to a method and a composition for preparing a water-based modified nanomaterial. Background Art

[0002] Horizontal wells and hydraulic fracturing are the primary methods used to extract oil and natural gas from tight oil and gas reservoirs. Currently, exploration and development in the tight clastic rock field continues to deepen. Reservoir fracturing is facing challenges with denser clastic reservoir matrices, smaller pores, narrower throats, and more complex clay content. These unfavorable factors have significantly impacted the post-fracture production and stable production capacity of clastic oil and gas wells, necessitating in-depth research. Fracturing fluid is primarily used to create fractures and carry sand. During the extension of hydraulic fractures, the pressure within the hydraulic fractures is much higher than the formation rock pressure, resulting in a large pressure differential. This causes some of the fluid to filter through the fracture walls into the reservoir. The utilization coefficient of the fracturing fluid (also known as the fracturing fluid efficiency) is typically only 0.3 to 0.5, or even lower. This means that nearly half of the fracturing fluid fails to create fractures or carry sand, but instead filters into the rock pores. Fracturing fluid filtration will have an adverse effect on fracturing construction: first, it reduces the fracture width and length. The narrower the fracture, the more serious the shear degradation of the fracturing fluid and the greater the filtration loss. The filtration loss of the sand-carrying fluid will increase the sand ratio in the fracture. When it increases to a certain level, the fracturing fluid can no longer carry the proppant forward, the construction pressure rises sharply, and the pump is forced to stop. At this time, sand shedding (sand blockage) occurs in the fracture, making the sand addition plan impossible to execute.

[0003] Tight clastic reservoirs are characterized by low permeability, high sensitivity, low porosity, complex pore throat structures, and severe heterogeneity. During the fracturing and completion process, tight oil and gas reservoirs experience significant permeability damage that is difficult to recover. Reservoir damage manifests itself macroscopically as a decrease in permeability. Microscopically, fracturing fluid filtration, allowing filtrate to enter the reservoir, can cause reservoir damage due to the following factors:

[0004] (1) When the fracturing fluid filtrate comes into contact with the water-sensitive clay in the reservoir, it causes hydration, expansion, dispersion, migration, and flocculation, blocking the pores and channels of fluid flow, resulting in varying degrees of permeability reduction;

[0005] (2) Filtrate entering the reservoir causes blockage due to physical reasons, namely water lock;

[0006] (3) The intrusion of filtrate changes the oil-water distribution in the oil layer, resulting in a decrease in the oil phase permeability. On the other hand, the discontinuous phase forms liquid droplets in the state of two-phase co-flow in the pores. The liquid droplets produce a capillary force effect that hinders the flow during the flow process - the Jiamin effect;

[0007] (4) Wettability change damage refers to the damage caused by the adsorption of chemicals on the rock to change the wettability of the rock surface, resulting in a decrease in oil phase permeability;

[0008] (5) The filtrate is not compatible with the reservoir fluid, resulting in a decrease in permeability.

[0009] Currently, to protect the permeability of oil and gas reservoirs and increase oil and gas well production, a common reservoir protection practice is to add waterproofing agents to well fluids such as fracturing fluids and completion fluids. This allows water from the external fluid to penetrate the pores of dense clastic rocks and then flow out more easily, thereby opening up channels and facilitating oil and gas production. However, because the pores of dense clastic rocks have reached the micro-nano level, capillary resistance is very high. Conventional waterproofing agents are not ideal for fracturing gas wells in dense clastic reservoirs such as Daniudi and Hangjin Banner. Summary of the Invention

[0010] To address the problem that conventional water-blocking agents in the prior art are not ideal for improving reservoir permeability and increasing oil and gas well production during fracturing of gas wells in tight clastic reservoirs, the present invention aims to provide a method and composition for preparing a water-based modified nanomaterial. The composition, containing the water-based modified nanomaterial prepared by the method, is a nano-penetrant that can be used for fracturing tight reservoirs to increase oil and gas well production.

[0011] To achieve the above object, the present invention provides a method for preparing a water-based modified nanomaterial, comprising the following steps:

[0012] A. mixing a nanomaterial source water-soluble compound, a first surfactant, a first alcohol compound, and water to obtain a first mixture;

[0013] B. allowing the first organic acid-hydrochloric acid mixed solution to undergo a first reaction with the first mixture or allowing the carbonate-second organic acid mixed solution to undergo a second reaction with the first mixture to obtain the water-based modified nanomaterial.

[0014] In one embodiment of the present invention, the mass ratio of the nanomaterial source water-soluble compound to the first surfactant is (0.2 to 1.5): (0.1 to 3); and / or

[0015] Taking the mass of the first mixture as 100%, the total amount of the nanomaterial source water-soluble compound and the first surfactant is 0.8wt% to 3.5wt%; the amount of the first alcohol compound is 1wt% to 5wt%; the amount of water is 92wt% to 98wt%; and / or

[0016] The mass ratio of the total mass of the nanomaterial source water-soluble compound and the first surfactant to the first organic acid-hydrochloric acid mixture, and the mass ratio of the total mass of the nanomaterial source water-soluble compound and the first surfactant to the carbonate-second organic acid mixture are independently (0.9 to 3): (1 to 2.5);

[0017] Preferably, taking the total mass of the first organic acid-hydrochloric acid mixture as 100%, the first organic acid-hydrochloric acid mixture comprises 10 wt % of the first organic acid, 10 wt % of HCl and the balance of water; and / or

[0018] The total mass of the carbonate-second organic acid mixed solution is calculated as 100%, and the carbonate-second organic acid mixed solution includes 10 wt % carbonate, 1 wt % second organic acid and the balance water.

[0019] In one embodiment of the present invention, the mass ratio of the nanomaterial source water-soluble compound to the first surfactant is (0.2 to 1): (0.1 to 2); and / or

[0020] Taking the mass of the first mixture as 100%, the total amount of the nanomaterial source water-soluble compound and the first surfactant is 0.9wt% to 3.1wt%; the amount of the first alcohol compound is 1wt% to 4.7wt%; the amount of water is 92.3wt% to 97.8wt%; and / or

[0021] The mass ratio of the total mass of the nanomaterial source water-soluble compound and the first surfactant to the first organic acid-hydrochloric acid mixture, and the mass ratio of the total mass of the nanomaterial source water-soluble compound and the first surfactant to the carbonate-second organic acid mixture are independently (0.9 to 3): (1.1 to 2.2).

[0022] In a specific embodiment of the present invention, the nanomaterial source water-soluble compound is selected from at least one of sodium metasilicate, calcium chloride, calcium hydroxide, aluminum trichloride, aluminum isopropoxide, titanium tetrachloride and titanyl sulfate; and / or

[0023] The first surfactant is selected from at least one of sodium lauryl sulfate, sodium dodecylbenzene sulfonate, lauryl betaine, OP-10 and NP-10; and / or

[0024] The first alcohol compound is an alcohol compound containing carbon atoms ranging from C1 to C5; and / or

[0025] The first organic acid is selected from lactic acid and / or succinic acid; and / or

[0026] The second organic acid is citric acid; and / or the carbonate is sodium carbonate;

[0027] Preferably, the nanomaterial source water-soluble compound is at least one selected from sodium metasilicate, calcium chloride, aluminum trichloride and titanium tetrachloride; and / or

[0028] The first alcohol compound is an alcohol compound containing carbon atoms ranging from C1 to C4;

[0029] Preferably, the first alcohol compound is at least one selected from ethanol, ethylene glycol, methanol, n-butanol, isobutanol and butanediol.

[0030] In the present invention, OP-10 is dodecylphenol polyoxyethylene ether, and NP-10 is nonylphenol polyoxyethylene ether (10).

[0031] In one embodiment of the present invention, the first mixture is first heated to 75° C. to 180° C., and then the step B is performed; and / or

[0032] In step B, the first organic acid-hydrochloric acid mixture is added dropwise to the first mixture while stirring, and then the first reaction is carried out; or the carbonate-second organic acid mixture is added dropwise to the first mixture while stirring, and then the second reaction is carried out; and / or

[0033] The reaction product obtained by the first reaction or the second reaction is cooled to room temperature (25° C.) to obtain the water-based modified nanomaterial.

[0034] In one embodiment of the present invention, the conditions of the first reaction and the second reaction are independently 75°C to 180°C for 20 min to 40 min;

[0035] Preferably, the reaction time of the first reaction and the second reaction is independently 30 minutes.

[0036] The second aspect of the present invention provides a water-based modified nanomaterial prepared by the method described in the first aspect of the present invention.

[0037] In a specific embodiment of the present invention, in the water-based modified nanomaterial, the modified nanomaterial is at least one of modified nano-silicon dioxide, modified nano-metal oxide and modified nano-carbonate;

[0038] Preferably, the particle size of the modified nano-silica is 5 nm to 10 nm; and / or

[0039] The particle size of the modified nano metal oxide is 10 nm to 50 nm; and / or

[0040] The particle size of the modified nanocarbonate is 10 nm to 30 nm.

[0041] In a specific embodiment of the present invention, the modified nano metal oxide is modified nano aluminum oxide and / or modified nano titanium oxide; and / or

[0042] The modified nano-carbonate is modified nano-calcium carbonate;

[0043] Preferably, the particle size of the modified nano-alumina is 10 nm to 30 nm; and / or the particle size of the modified nano-titanium oxide is 10 nm to 50 nm.

[0044] The third aspect of the present invention provides a composition comprising a water-based modified nanomaterial, a second surfactant and an adjuvant;

[0045] The water-based modified nanomaterial is the water-based modified nanomaterial prepared by the method described in the first aspect of the present invention or the water-based modified nanomaterial described in the second aspect of the present invention.

[0046] In one embodiment of the present invention, the mass of the composition is calculated as 100%, and the composition includes 1.5 wt% to 4 wt% of the second surfactant, 2.5 wt% to 7 wt% of the auxiliary agent and 90 wt% to 95 wt% of the water-based modified nanomaterial;

[0047] Preferably, taking the mass of the composition as 100%, the composition includes 1.9 wt % to 3.9 wt % of the second surfactant, 2.9 wt % to 6.9 wt % of the auxiliary agent and 90.3 wt % to 93.2 wt % of the water-based modified nanomaterial.

[0048] In one embodiment of the present invention, the second surfactant is an anionic surfactant and / or a nonionic surfactant; and / or

[0049] The auxiliary agent is a mixture of a second alcohol compound, a third organic acid and a mutual solvent; and / or

[0050] The mass of the auxiliary agent is calculated as 100%, and the auxiliary agent includes 30 wt % to 82 wt % of the second alcohol compound, 1.5 wt % to 20 wt % of the third organic acid and 15 wt % to 65 wt % of the mutual solvent;

[0051] Preferably, the molecular weight of the second surfactant is 270 to 3000; and / or

[0052] The second alcohol compound is an alcohol compound containing carbon atoms ranging from C1 to C5;

[0053] Preferably, the second alcohol compound is an alcohol compound containing carbon atoms ranging from C1 to C4;

[0054] Preferably, taking the mass of the auxiliary agent as 100%, the auxiliary agent includes 32 wt % to 82 wt % of the second alcohol compound, 1.6 wt % to 20 wt % of the third organic acid and 16 wt % to 64.6 wt % of the mutual solvent.

[0055] In a specific embodiment of the present invention, the second surfactant is selected from at least one of sodium lauryl alcohol polyoxyethylene ether sulfate, triethanolamine lauryl sulfate, sodium N-lauroyl glutamate and sodium lauryl alcohol polyoxyethylene ether carboxylate; and / or

[0056] The second alcohol compound is selected from at least one of methanol, ethanol, ethylene glycol, butanediol, n-butanol and isobutanol; and / or

[0057] The third organic acid is selected from at least one of glycolic acid, lactic acid, citric acid and succinic acid; and / or

[0058] The mutual solvent is ethyl acetate and / or maleic acid;

[0059] Preferably, the sodium lauryl polyoxyethylene ether carboxylate is selected from at least one of sodium laureth-6 acetate, sodium laureth-9 acetate and sodium laureth-9 propionate; and / or

[0060] The second alcohol compound is selected from at least one of methanol, ethanol and ethylene glycol; and / or

[0061] The third organic acid is selected from at least one of citric acid, glycolic acid and lactic acid.

[0062] The use of any one of the water-based modified nanomaterials prepared by the method described in the first aspect of the present invention, the water-based modified nanomaterials described in the second aspect of the present invention, and the composition described in the third aspect of the present invention in the hydraulic fracturing transformation of tight oil and gas reservoirs, especially as a penetrant in the hydraulic fracturing transformation of tight oil and gas reservoirs.

[0063] Beneficial effects of the present invention:

[0064] To address the problem that conventional water-blocking agents in the prior art are not ideal for improving reservoir permeability and oil and gas well production during fracturing of dense clastic reservoirs, the present invention provides a method and composition for preparing a water-based modified nanomaterial. The composition comprises the water-based modified nanomaterial prepared by the method, a second surfactant, and an additive, and is a nano-penetrant. At room temperature, the surface tension of the composition is 19.0 to 22.4 mN / m, and its interfacial tension with kerosene is 0.9 to 1.35 mN / m, which meets the requirements of the fracturing fluid industry standard "SYT 6376-2008 General Technical Conditions for Fracturing Fluids" that the surface tension of fracturing fluid is ≤28.0 mN / m and the interfacial tension with kerosene is ≤2.0 mN / m. At room temperature, the gas well production improvement rate of the composition is 22.29% to 34.56%, and the oil well production improvement rate is 13.46% to 39.58%, improving the production of both gas and oil wells. At room temperature, the pressure difference required for gas flow in an artificial core injected with the composition is only 0.16 to 0.2 MPa, which is lower than the pressure difference of 0.3 MPa required for gas flow in an artificial core injected with distilled water. The composition can significantly improve the production capacity of gas wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 The infrared spectra of the compositions prepared in Example 1 and Example 2;

[0066] Figure 2 This is a scanning electron microscope image of the water-based modified nanomaterial prepared in Example 1;

[0067] Figure 3 This is a scanning electron microscope image of the water-based modified nanomaterial prepared in Example 2;

[0068] Figure 4 This is a scanning electron microscope image of the water-based modified nanomaterial prepared in Example 4;

[0069] Figure 5 The displacement pressure difference-displacement time curves obtained by testing the gas phase flow pressure of the artificial core under saturated irreducible water conditions using the composition prepared in Example 1 and distilled water respectively;

[0070] Figure 6 The displacement pressure difference-displacement time curve obtained by testing the gas phase flow pressure of the artificial core under saturated irreducible water conditions using the composition prepared in Example 2 and distilled water respectively;

[0071] Figure 7 The displacement pressure difference-displacement time curves obtained by testing the gas phase flow pressure of the artificial core under saturated irreducible water conditions using the composition prepared in Example 4 and distilled water, respectively;

[0072] Figure 8The displacement pressure difference-displacement time curves are obtained by testing the gas phase flow pressure of the artificial core under saturated irreducible water conditions using the composition prepared in Comparative Example 1 and distilled water, respectively. DETAILED DESCRIPTION

[0073] The present invention will be further described below with reference to examples. However, the examples are merely illustrative and do not limit the present invention in any way.

[0074] The lactic acid-hydrochloric acid mixture used in Examples 1, 2, and 5:

[0075] A lactic acid-hydrochloric acid mixture was prepared using lactic acid, hydrochloric acid (analytical grade) with a HCl mass fraction of 36 wt %, and water, where the mass of the lactic acid-hydrochloric acid mixture was taken as 100%. The lactic acid-hydrochloric acid mixture comprised 10 wt % lactic acid, 10 wt % HCl, and the balance water.

[0076] The sodium carbonate-citric acid mixture used in Example 3:

[0077] 10 g of sodium carbonate, 1 g of citric acid and 89 g of water were mixed to obtain a sodium carbonate-citric acid mixture, where the mass of the sodium carbonate-citric acid mixture was taken as 100%. The sodium carbonate-citric acid mixture included 10 wt % of sodium carbonate, 1 wt % of citric acid and the balance of water.

[0078] The succinic acid-hydrochloric acid mixture used in Example 4:

[0079] A succinic acid-hydrochloric acid mixture was prepared using butanediol, hydrochloric acid (analytical grade) with a HCl mass fraction of 36 wt%, and water, where the mass of the succinic acid-hydrochloric acid mixture was taken as 100%. The succinic acid-hydrochloric acid mixture comprised 10 wt% succinic acid, 10 wt% HCl, and the balance water.

[0080] Example 1

[0081] Preparation of water-based modified nanomaterials:

[0082] A. Add 90 mL of distilled water and 1 g of sodium metasilicate to a reaction vessel connected to a reflux condenser. After the sodium metasilicate is fully dissolved, add 0.1 g of sodium lauryl sulfate, 0.5 g of ethanol, and 0.5 g of ethylene glycol. Stir evenly and heat to 75° C. to obtain a first mixture.

[0083] B. Maintaining a constant temperature of 75° C., while rapidly stirring the first mixture, slowly adding 1.1 g of a lactic acid-hydrochloric acid mixture at a rate of 3 to 5 drops / minute. After the addition is complete, stirring at a constant temperature of 75° C. for 30 minutes, and cooling to room temperature to obtain water-based modified nano-silica, which can be directly used to prepare the composition;

[0084] Preparation of the composition:

[0085] 1) Weigh 3.0 g of methanol, 1.0 g of citric acid, and 1.0 g of ethyl acetate, mix with 93.2 g of the water-based modified nano-silica prepared in this example, and stir evenly to obtain a second mixture;

[0086] 2) Weigh 2.0 g of sodium lauryl alcohol polyoxyethylene ether sulfate (molecular weight 332.4) and 0.5 g of sodium N-lauroyl glutamate (molecular weight 350.4), mix them with the second mixture, and stir evenly to obtain a composition, a nano-penetrant.

[0087] Example 2

[0088] Preparation of water-based modified nanomaterials:

[0089] A. Add 90 mL of distilled water and 1 g of sodium metasilicate to a reaction vessel connected to a reflux condenser. After the sodium metasilicate is fully dissolved, add 1.0 g of dodecyl betaine, 1.0 g of OP-10, 2 g of methanol, and 2.5 g of n-butanol. Stir evenly and then heat to 75° C. to obtain a first mixture.

[0090] B. Maintaining a constant temperature of 75° C., while rapidly stirring the first mixture, slowly adding 1.1 g of a lactic acid-hydrochloric acid mixture at a rate of 3 to 5 drops / minute. After the addition is complete, stirring at a constant temperature of 75° C. for 30 minutes, and cooling to room temperature to obtain water-based modified nano-silica, which can be directly used to prepare the composition;

[0091] Preparation of the composition:

[0092] 1) Weigh 3.0 g of ethanol, 1.0 g of glycolic acid, and 1.0 g of ethyl acetate, mix with 98.6 g of the water-based modified nano-silica prepared in this example, and stir evenly to obtain a second mixture;

[0093] 2) 2.5 g of sodium laureth-6 acetate (molecular weight 506.5) and 0.5 g of sodium N-lauroyl glutamate were weighed and mixed with the second mixture, and stirred to obtain a composition, a nano-penetrant.

[0094] Example 3

[0095] Preparation of water-based modified nanomaterials:

[0096] A. Add 90 mL of distilled water and 0.5 g of calcium chloride to a reaction vessel connected to a reflux condenser. After the calcium chloride is fully dissolved, add 0.5 g of sodium dodecylbenzenesulfonate, 2 g of isobutanol, and 1.5 g of butanediol. Stir evenly and then heat to 140° C. to obtain a first mixture.

[0097] B. Maintaining a constant temperature of 140° C., while rapidly stirring the first mixture, slowly adding 2.1 g of a sodium carbonate-citric acid mixture at a rate of 3 to 5 drops / minute. After the addition is complete, stirring at a constant temperature of 140° C. for 30 minutes, cooling to room temperature, and obtaining a water-based modified nano-calcium carbonate, which can be directly used to prepare a composition;

[0098] Preparation of the composition:

[0099] 1) Weigh 1.0 g of ethylene glycol, 0.1 g of glycolic acid, and 2.0 g of ethyl acetate, mix with 96.6 g of the water-based modified nano-calcium carbonate prepared in this example, and stir evenly to obtain a second mixture;

[0100] 2) Weigh 2.5 g of sodium laureth-9 acetate (molecular weight 626.5) and 1.5 g of triethanolamine lauryl sulfate (molecular weight 430), mix them with the second mixture, and stir evenly to obtain a composition, a nano-penetrant.

[0101] Example 4

[0102] Preparation of water-based modified nanomaterials:

[0103] A. Add 90 mL of distilled water and 1 g of aluminum chloride to a reaction vessel connected to a reflux condenser. After the aluminum chloride is fully dissolved, add 0.1 g of OP-10, 0.1 g of NP-10, 1 g of ethanol, and 1 g of ethylene glycol. Stir evenly and heat to 180° C. to obtain a first mixture.

[0104] B. Maintaining a constant temperature of 180° C., while rapidly stirring the first mixture, slowly add 2.1 g of a succinic acid-hydrochloric acid mixture at a rate of 3 to 5 drops / minute. After the addition is complete, stir at a constant temperature of 180° C. for 30 minutes, and cool to room temperature to obtain a water-based modified nano-alumina, which can be directly used to prepare a composition;

[0105] Preparation of the composition:

[0106] 1) Weigh 5.0 g of ethanol, 0.2 g of lactic acid, and 2.0 g of maleic acid, mix with 95.3 g of the water-based modified nano-alumina prepared in this example, and stir evenly to obtain a second mixture;

[0107] 2) Weigh 2.5 g of sodium laureth-6 acetate (molecular weight 506.5) and 0.5 g of sodium laureth-9 propionate (molecular weight 640.5), mix them with the second mixture, and stir evenly to obtain a composition, a nano-penetrant.

[0108] Example 5

[0109] Preparation of water-based modified nanomaterials:

[0110] A. Add 90 mL of distilled water and 0.2 g of titanium tetrachloride to a reaction vessel connected to a reflux condenser. After the titanium tetrachloride is fully dissolved, add 0.5 g of sodium lauryl sulfate, 0.2 g of NP-10, 1 g of ethanol, and 1 g of methanol. Stir evenly and then heat to 180° C. to obtain a first mixture.

[0111] B. Maintaining a constant temperature of 180° C., while rapidly stirring the first mixture, slowly adding 2.2 g of a lactic acid-hydrochloric acid mixture at a rate of 3 to 5 drops / minute. After the addition is complete, stirring at a constant temperature of 180° C. for 30 minutes, and cooling to room temperature to obtain a water-based modified nano-titanium oxide, which can be directly used to prepare a composition;

[0112] Preparation of the composition:

[0113] 1) Weigh 5.0 g of ethylene glycol, 0.1 g of citric acid, and 1.0 g of ethyl acetate, mix with 95.1 g of the water-based modified nano-titanium oxide prepared in this example, and stir evenly to obtain a second mixture;

[0114] 2) Weigh 1.0 g of sodium lauryl alcohol polyoxyethylene ether sulfate and 1.0 g of sodium laureth-9 propionate, mix them with the second mixture, and stir evenly to obtain a composition, a nano-penetrant.

[0115] The lactic acid-hydrochloric acid mixture used in Comparative Example 1:

[0116] A lactic acid-hydrochloric acid mixture was prepared using lactic acid, hydrochloric acid (analytical grade) with a HCl mass fraction of 36 wt%, and water, where the mass of the lactic acid-hydrochloric acid mixture was taken as 100%. The lactic acid-hydrochloric acid mixture comprised 10 wt% lactic acid, 10 wt% HCl, and the balance water.

[0117] Comparative Example 1

[0118] Preparation of water-based modified nanomaterials

[0119] A. Add 90 mL of distilled water and 1 g of sodium metasilicate to a reaction vessel connected to a reflux condenser. After the sodium metasilicate is fully dissolved, add 0.2 g of sodium lauryl sulfate, 0.5 g of ethanol, and 0.5 g of ethylene glycol. Stir evenly and heat to 75° C. to obtain a first mixture.

[0120] B. Maintaining a constant temperature of 75° C., while rapidly stirring the first mixture, slowly adding 1.1 g of a lactic acid-hydrochloric acid mixture at a rate of 3 to 5 drops / minute. After the addition is complete, stirring at a constant temperature of 75° C. for 30 minutes, and cooling to room temperature to obtain water-based modified nano-silica, which can be directly used to prepare the composition;

[0121] Preparation composition:

[0122] 7.5 g of water was added to 93.3 g of the water-based modified nano-silica prepared in this comparative example, and the mixture was stirred uniformly to obtain a composition, a nano-penetrant.

[0123] Comparative Example 2

[0124] Preparation composition:

[0125] 1) Weigh 3.0 g of propanol, 0.2 g of sulfuric acid, and 1.0 g of butyl acetate, mix with 93.2 g of the water-based modified nano-silica prepared in Example 1, and stir evenly to obtain a second mixture;

[0126] 2) Weigh 2.0 g of sodium tetradecylsulfonate, mix it with the second mixture, and stir evenly to obtain a composition, a nano-penetrant.

[0127] Comparative Example 3

[0128] Get samples of nano-injection additives for oilfield water injection:

[0129] Samples of nano-injection agents for oilfield water injection produced by Henan Wangwu Nano-Tech Co., Ltd.: nano-polysilicon pressure-reducing and injection-increasing agent NPS-ZY;

[0130] The main components of the nano-polysilicon pressure-reducing and injection-increasing agent NPS-ZY are: 20wt% to 60wt% diesel, 10wt% to 30wt% surfactant, 1wt% to 10wt% nano-silicon dioxide and the balance additives.

[0131] Experimental evaluation

[0132] 1. Infrared spectroscopy of the composition

[0133] After drying and washing the compositions prepared in Example 1 and Example 2, their infrared spectra were measured using a Fourier transform infrared spectrometer. Figure 1 .

[0134] from Figure 1 It can be seen that: (1) In the infrared spectra of the compositions prepared in Example 1 and Example 2, obvious SiO2 characteristic absorption peaks can be observed, among which 1095 cm -1 The strong absorption peak at 800 cm is caused by the antisymmetric stretching vibration of Si-O-Si bond. -1 The absorption peaks on the left and right are the symmetrical stretching vibration absorption peaks of the Si-O-Si bond, at 460 cm -1 The absorption peaks appearing around 1673 cm are due to the bending vibration of Si-O bonds, proving that there is a large amount of silicon dioxide in the composition. (2) At 1673 cm -1The characteristic absorption peak at 3194 cm is the stretching vibration absorption peak of the C=O bond in the polyoxyethylene ether group, proving that sodium dodecyl alcohol polyoxyethylene ether sulfate or sodium lauryl polyether-6 acetate is adsorbed on the surface of the nanomaterial in the composition; (3) at 3194 cm -1 The characteristic absorption peak at 1412 cm is the stretching vibration absorption peak of the -NH bond in sodium N-lauroyl glutamate (amide II peak), -1 The characteristic absorption peak at is a mixed peak (amide III peak) of the stretching vibration absorption peak of the CN bond and the bending vibration absorption peak of the NH bond, which proves the presence of molecular chains such as sodium N-lauroyl glutamate on the surface of the nanomaterial in the composition.

[0135] 2. Morphological observation of water-based modified nanomaterials and particle size determination of modified nanomaterials

[0136] ⅰ Observation of the morphology of water-based modified nanomaterials

[0137] Taking the water-based modified nanomaterials prepared in Examples 1, 2, and 4 as an example, the morphology of the water-based modified nanomaterials was observed using a scanning electron microscope. Figures 2 to 4 .

[0138] Figures 2 to 4 The scanning electron microscope images of the water-based modified nano-silica prepared in Example 1, the water-based modified nano-silica prepared in Example 2, and the water-based modified nano-alumina prepared in Example 4 are shown in order, with a magnification of 20.0×10 6 times, Figure 2 、 Figure 3 It shows that the modified nano-silica in the water-based modified nano-silica prepared in Examples 1 and 2 does not agglomerate and is well dispersed. Figure 4 It shows that the modified nano-alumina in the water-based modified nano-alumina prepared in Example 4 does not agglomerate and is in good dispersion.

[0139] Under a scanning electron microscope, it can also be observed that the modified nano-calcium carbonate in the water-based modified nano-calcium carbonate prepared in Example 3 and the modified nano-titanium oxide in the water-based modified nano-titanium oxide prepared in Example 5 have good dispersibility and no agglomeration occurs.

[0140] ⅱ Determination of particle size of modified nanomaterials in water-based modified nanomaterials

[0141] The particle sizes of the modified nanomaterials in the water-based modified nanomaterials prepared in Examples 1 to 5 and Comparative Example 1 were measured using a Mastersizer 3000 laser particle size analyzer. The specific results are shown in Table 1.

[0142] Table 1. Particle size range of modified nanomaterials prepared in Examples 1 to 5 and Comparative Example 1

[0143] Serial number Types of modified nanomaterials Particle size range / nm Example 1 Modified nanosilica 5 to 10 Example 2 Modified nanosilica 5 to 10 Example 3 Modified nano calcium carbonate 10 to 30 Example 4 Modified nano-alumina 10 to 30 Example 5 Modified nano-titanium oxide 10 to 50 Comparative Example 1 Modified nanosilica 10 to 15

[0144] As can be seen from Table 1, the particle size of the modified nano-silica prepared in Examples 1 and 2 is 5 to 10 nm; the particle size of the modified nano-calcium carbonate prepared in Example 3 is 10 to 30 nm; the particle size of the modified nano-alumina prepared in Example 4 is 10 to 30 nm, and the particle size of the modified nano-titanium oxide prepared in Example 5 is 10 to 50 nm, which are suitable for hydraulic fracturing transformation of tight oil and gas reservoirs.

[0145] 3. Surface tension of the composition and interfacial tension with kerosene

[0146] The surface tension and interfacial tension between the compositions prepared in Examples 1 to 5, Comparative Examples 1 and 2, and the nano-polysilicon pressure-reducing and injection-increasing agent NPS-ZY in Comparative Example 3 were measured at room temperature (25°C) using a K100 interfacial tension meter. Each example and comparative example was measured three times. The specific results are shown in Table 2. Since the nano-polysilicon pressure-reducing and injection-increasing agent NPS-ZY in Comparative Example 3 is primarily composed of diesel fuel, no interfacial tension could be measured between it and kerosene. Therefore, no interfacial tension data for Comparative Example 3 is included in the row in Table 2.

[0147] Table 2. Surface tension of the composition and interfacial tension between the composition and kerosene at room temperature

[0148]

[0149] In Table 2, the surface tension of the compositions prepared in Examples 1 to 5 and the interfacial tension between the compositions and kerosene were 19 to 22.4 mN / m and 0.9 to 1.35 mN / m, respectively, which meet the requirements of the fracturing fluid industry standard "SYT 6376-2008 General Technical Conditions for Fracturing Fluids" for the fracturing fluid surface tension ≤ 28.0 mN / m and the interfacial tension with kerosene ≤ 2.0 mN / m. The surface tension of the nano-polysilicon pressure-reducing and injection-enhancing agent NPS-ZY in Comparative Example 3 was 42.1 to 47.3 mN / m, which obviously did not meet the above standards.

[0150] 4. Evaluation of the Composition's Ability to Improve Oil and Gas Well Production

[0151] Due to experimental conditions, the oil industry currently mainly conducts sand-filled pipe displacement experiments to evaluate the impact of fluids or agents injected into oil and gas reservoirs on oil and gas well production. Here, sand-filled pipe displacement experiments were used to measure the improvement effect of the compositions prepared in Examples 1 to 5, Comparative Examples 1 and 2, and the nano-polysilicon pressure-reducing and injection-increasing agent NPS-ZY in Comparative Example 3 on oil and gas well production at room temperature (25°C) to evaluate their ability to improve oil and gas well production. The specific experimental steps are as follows:

[0152] (1) Use Ø50mm×500mm stainless steel pipes, tightly fill them with 200 mesh quartz sand, and make multiple sets of sand-filled pipes;

[0153] (2) After the sand-filled tubes prepared in step (1) were evacuated and saturated with distilled water, air or kerosene at 10 PV or more was injected into them until the outlet no longer contained water. The pressure difference between the inlet and outlet of the sand-filled tubes was measured to calculate the gas permeability K under the condition of bound water. gas , oil phase permeability K oil This permeability can represent the gas and oil production capacity under simulated oil and gas reservoir conditions, and serve as a simulation test result of the production situation of oil and gas wells under reservoir conditions.

[0154] (3) Take the above measured gas permeability K gas , oil phase permeability K oil The sand filling pipe was filled with the compositions prepared in Examples 1 to 5 and Comparative Examples 1 and 2, and the nano-polysilicon pressure-reducing and injection-increasing agent NPS-ZY in Comparative Example 3, respectively, with an injection volume of 1.0 PV.

[0155] (4) After the composition (or nano-polysilicon pressure-reducing and injection-increasing agent NPS-ZY) is injected into the sand-filled pipe, air or kerosene is injected at 10PV or more, respectively, until the outlet end no longer contains water. The pressure difference between the inlet and outlet ends of the sand-filled pipe is measured, and the gas phase permeability K2 after the nano-permeation agent is improved is calculated. gas , oil phase permeability K2 oil This permeability can represent the gas and oil production capacity of the simulated oil and gas reservoir after using the nano-permeability agent, and is related to the gas phase permeability K gas , oil phase permeability K oil By comparison, you can observe and compare the improvement effect of oil and gas well production after the injection of nano-permeation agent;

[0156] It should be noted that in this experiment, the sand-filling pipes for gas injection and kerosene injection cannot be mixed; the above steps (1) to (4) are all carried out at room temperature (25°C), as shown in Table 3.

[0157] Table 3. Comparison of production status and improvement effect of oil and gas wells before and after injection of the composition

[0158]

[0159] As can be seen from Table 3, the gas well improvement rates of the compositions prepared in Examples 1 to 5 reached 22.29% to 34.56%, and the oil well improvement rates reached 13.46% to 39.58%. The gas well improvement rates of the compositions prepared in Comparative Examples 1 and 2 were 4.63% to 5.19%, and the oil well improvement rates were 4.55% to 7.84%. The gas well improvement rate of the nano-polysilicon pressure-reducing and injection-increasing agent NPS-ZY in Comparative Example 3 was 2.63%, and the oil well improvement rate was -1.78%. The compositions prepared in Examples 1 to 5 were significantly superior to the compositions prepared in Comparative Examples 1 and 2 and the nano-polysilicon pressure-reducing and injection-increasing agent NPS-ZY in Comparative Example 3 in improving gas well production and oil well production. From a formulation perspective, compared to Examples 1 to 5, the composition prepared in Comparative Example 1 lacks the second alcohol compound, the third organic acid, the mutual solvent, and the second surfactant, resulting in a much lower oil and gas well yield improvement rate compared to the compositions prepared in Examples 1 to 5. Comparative Example 2 replaces the third organic acid with sulfuric acid, an inorganic acid, and uses a different first surfactant and mutual solvent than those in Examples 1 to 5. This also results in a significantly lower oil and gas well yield improvement rate compared to the compositions prepared in Examples 1 to 5. This demonstrates that there is synergy between the components in the compositions prepared in Examples 1 to 5, and that the lack of raw materials and the type of raw materials can also affect the composition's ability to improve oil and gas well yields.

[0160] 5. Performance evaluation of the composition for improving gas well productivity

[0161] The gas flow pressure of the compositions prepared in Examples 1, 2, 4, and Comparative Example 1 and distilled water on artificial cores under saturated bound water conditions was measured to evaluate the performance of the compositions in improving gas well productivity. The specific experimental methods are as follows:

[0162] ① Purchase dense sandstone artificial cores with a permeability of about 1.0mD. The core specifications follow the standard dimensions of common core experiments: core diameter 25.4mm, length 100mm. The actual initial gas permeability shall be based on the experimental test data;

[0163] ② After the cores of step ① were vacuum-saturated with distilled water, air was continuously injected, starting with the first drop of water flowing out of the outlet end. The air injection pressure and flow rate were controlled so that no more than 0.2 g of distilled water dripped from the outlet end per minute. During the injection process, the pressure difference between the inlet and outlet ends of the core was continuously measured and recorded. This pressure difference can represent the gas production capacity under the conditions of the simulated oil and gas reservoir, which is used as a simulation test result of the production of the gas well under conventional conditions (i.e., normal production conditions without injection of the composition prepared by the present invention).

[0164] ③ After the core of step ② is re-vacuumed and saturated with the composition, the composition is continuously injected for a total of 1.0 PV. When the liquid collected at the outlet reaches 1.0 PV, the injection of the composition can be stopped.

[0165] ④ Continuously inject air into the core of step ③, starting with the first drop of water flowing out of the outlet end, and control the air injection pressure and flow rate so that the distilled water dripping from the outlet end does not exceed 0.2g per minute. During the injection process, continuously measure and record the pressure difference between the inlet and outlet ends of the core. This pressure difference can represent the gas production capacity under the conditions of the simulated oil and gas reservoir, and serve as a simulation test result of the production situation of the gas well under the conditions of injecting the composition.

[0166] ⑤ Plot the pressure difference data recorded in step ② and step ④. This pressure difference can represent the gas production capacity of the underground gas reservoir under normal conditions and when the composition is injected, so as to observe and compare the production improvement effect of the gas well after the composition is injected.

[0167] ⑥After the test is completed, replace the core and conduct the next test.

[0168] According to the above steps ① to ⑥, the compositions prepared in Examples 1, 2, 4 and Comparative Example 1 were tested, and the test results were shown in the table below. Figures 5 to 8 .

[0169] from Figures 5 to 7 As can be seen, the pressure difference required for gas flow in the artificial cores injected with the compositions prepared in Example 1, Example 2, and Example 4 is approximately 0.2 MPa, 0.2 MPa, and 0.16 MPa, respectively, which is much lower than the pressure difference of 0.3 MPa required for gas flow in the artificial core injected with distilled water. Figure 8 It is shown in Figure 1 that the pressure difference required for gas flow in the artificial core injected with the composition prepared in Comparative Example 1 is 0.25 MPa, which is higher than that of the compositions prepared in Examples 1, 2, and 4. Figures 5 to 8 The analysis shows that the composition prepared by the present invention has the ability to significantly improve the production capacity of gas wells.

[0170] Although the present invention has been described with reference to specific embodiments, those skilled in the art will appreciate that various modifications may be made without departing from the true spirit and scope of the invention. Furthermore, the subject matter, spirit, and scope of the invention may be modified in various ways to adapt to specific circumstances, materials, combinations of materials, and methods. All such modifications are intended to be within the scope of the claims.

Claims

1. A method for preparing a water-based modified nanomaterial, comprising the following steps: A. mixing a nanomaterial source water-soluble compound, a first surfactant, a first alcohol compound, and water to obtain a first mixture; B. allowing the first organic acid-hydrochloric acid mixed solution and the first mixture to undergo a first reaction or allowing the carbonate-second organic acid mixed solution and the first mixture to undergo a second reaction to obtain the water-based modified nanomaterial; in, The nanomaterial source water-soluble compound is selected from at least one of sodium metasilicate, calcium chloride, calcium hydroxide, aluminum trichloride, aluminum isopropoxide, titanium tetrachloride and titanyl sulfate; and / or The first surfactant is selected from at least one of sodium lauryl sulfate, sodium dodecylbenzene sulfonate, lauryl betaine, OP-10 and NP-10; and / or The first alcohol compound is an alcohol compound containing carbon atoms ranging from C1 to C5; and / or The first organic acid is selected from lactic acid and / or succinic acid; and / or The second organic acid is citric acid.

2. The method according to claim 1, characterized in that The mass ratio of the nanomaterial source water-soluble compound to the first surfactant is (0.2 to 1.5): (0.1 to 3); and / or Taking the mass of the first mixture as 100%, the total mass of the nanomaterial source water-soluble compound and the first surfactant is 0.8wt% to 3.5wt%; the mass of the first alcohol compound is 1wt% to 5.0wt%; the mass of the water is 92wt% to 98wt%; and / or The mass ratio of the total mass of the nanomaterial source water-soluble compound and the first surfactant to the first organic acid-hydrochloric acid mixture, and the mass ratio of the total mass of the nanomaterial source water-soluble compound and the first surfactant to the carbonate-second organic acid mixture are independently (0.9 to 3): (1.0 to 2.5).

3. The method according to claim 1, characterized in that The total mass of the first organic acid-hydrochloric acid mixture is taken as 100%, and the first organic acid-hydrochloric acid mixture comprises 10 wt % of the first organic acid, 10 wt % of HCl and the balance of water; and / or The total mass of the carbonate-second organic acid mixture is taken as 100%, and the carbonate-second organic acid mixture includes 10 wt % of carbonate, 1 wt % of the second organic acid, and the balance of water.

4. The method according to any one of claims 1 to 3, characterized in that The first alcohol compound is an alcohol compound containing carbon atoms ranging from C1 to C4.

5. The method according to any one of claims 1 to 3, characterized in that The carbonate is sodium carbonate.

6. The method according to any one of claims 1 to 3, characterized in that The conditions for the first reaction and the second reaction are independently 75° C. to 180° C. for 20 to 40 minutes.

7. A water-based modified nanomaterial prepared by the method according to any one of claims 1 to 6.

8. The water-based modified nanomaterial according to claim 7, characterized in that: In the water-based modified nanomaterial, the modified nanomaterial is at least one of modified nano-silicon dioxide, modified nano-metal oxide and modified nano-carbonate.

9. The water-based modified nanomaterial according to claim 8, characterized in that: The particle size of the modified nano-silica is 5 nm to 10 nm; and / or The particle size of the modified nano metal oxide is 10 nm to 50 nm; and / or The particle size of the modified nanocarbonate is 10 nm to 30 nm.

10. The water-based modified nanomaterial according to claim 8, characterized in that: The modified nano metal oxide is modified nano aluminum oxide and / or modified nano titanium oxide; and / or The modified nano-carbonate is modified nano-calcium carbonate.

11. A composition comprising a water-based modified nanomaterial, a second surfactant, and an adjuvant; The water-based modified nanomaterial is a water-based modified nanomaterial prepared by the method according to any one of claims 1 to 6 or a water-based modified nanomaterial according to any one of claims 7 to 10; The second surfactant is at least one selected from sodium lauryl alcohol polyoxyethylene ether sulfate, triethanolamine lauryl sulfate, sodium N-lauroyl glutamate and sodium lauryl alcohol polyoxyethylene ether carboxylate.

12. The composition according to claim 11, characterized in that Taking the mass of the composition as 100%, the composition includes 1.5 wt % to 4 wt % of the second surfactant, 2.5 wt % to 7 wt % of the auxiliary agent, and 90 wt % to 95 wt % of the water-based modified nanomaterial.

13. The composition according to claim 11 or 12, characterized in that The molecular weight of the second surfactant is 270 to 3000.

14. The composition according to claim 11 or 12, characterized in that The auxiliary agent is a mixture of a second alcohol compound, a third organic acid and a mutual solvent; and / or The mass of the auxiliary agent is calculated as 100%, and the auxiliary agent includes 30 wt % to 82 wt % of the second alcohol compound, 1.5 wt % to 20 wt % of the third organic acid and 15 wt % to 65 wt % of the mutual solvent; Wherein, the second alcohol compound is an alcohol compound containing carbon atoms ranging from C1 to C5; The third organic acid is selected from at least one of glycolic acid, lactic acid, citric acid and succinic acid; and / or The mutual solvent is ethyl acetate and / or maleic acid.

15. The composition according to claim 14, characterized in that The second alcohol compound is an alcohol compound containing carbon atoms ranging from C1 to C4.

16. Use of any one of the water-based modified nanomaterial prepared by the method according to any one of claims 1 to 6, the water-based modified nanomaterial according to any one of claims 7 to 10, and the composition according to any one of claims 11 to 15 in hydraulic fracturing transformation of tight oil and gas reservoirs.

17. The use according to claim 16, characterized in that The application is as a penetrant in the hydraulic fracturing transformation of tight oil and gas reservoirs.

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