WO2024007750A1

WO2024007750A1 - Integrated fracturing fluid and preparation method therefor

Info

Publication number: WO2024007750A1
Application number: PCT/CN2023/095431
Authority: WO
Inventors: 熊颖; 张亚东; 张大椿; 黄晨直
Original assignee: 中国石油天然气股份有限公司
Priority date: 2022-07-07
Filing date: 2023-05-22
Publication date: 2024-01-11
Also published as: CN117402602A

Abstract

The present invention provides an integrated fracturing fluid and a preparation method therefor. The fracturing fluid comprises: 0.02-0.5% of a drag-reducing and viscosity-increasing agent, 0.1-0.5% of a nano-emulsion, 0.02-0.1% of a nonionic fluorocarbon surfactant, 0.003-0.05% of a bactericide, 0-0.5% of a viscosity modifier, 0-0.5% of a clay stabilizer, 0-0.1% of a gel breaker, 0.05-0.2% of a modifier, and 0.1-0.5% of a gas generating agent, with the balance being water. The preparation method for the fracturing fluid comprises: adding a drag-reducing and viscosity-increasing agent into water, and adding a bactericide, a clay stabilizer, a modifier, a nano-emulsion and a nonionic fluorocarbon surfactant; adding a viscosity modifier according to viscosity requirements; and then adding a gas generating agent and a gel breaker; or adding the gas generating agent and the gel breaker to a sand mixing tank to be mixed with the mixed solution and sand together. The integrated fracturing fluid provided by the present invention has low friction drag, adjustable viscosity, and high sand suspension performance under the same viscosity.

Description

Integrated fracturing fluid and preparation method thereof

Technical field

The invention relates to an integrated fracturing fluid and a preparation method thereof, and belongs to the technical field of oilfield chemistry.

Background technique

Unconventional oil and gas reservoirs such as shale oil and gas and tight oil and gas have become key and hot areas of oil and gas exploration and development. At present, the volume fracturing mode is mainly used for the stimulation of these unconventional oil and gas reservoirs, and the required fracturing fluids are mainly slick water and glue (including linear glue, jelly glue or weak gel). In the actual application process, variable viscosity slick water fracturing fluid with adjustable viscosity is more often used. When the viscosity is low, it is used as a general slick water fracturing fluid, when the viscosity is medium, it is used as a linear glue fracturing fluid, and when the viscosity is high, it is used as a weak gel. Or gel fracturing fluid. Low-viscosity fracturing fluids have low friction, but poor sand-suspending properties. High-viscosity fracturing fluids have good sand-suspending properties, but have high friction, and use high concentrations of drag-reducing agents or thickeners, which increase the cost of fracturing fluids. cost. In addition, if the viscosity is too high, the fracturing cracks will be relatively simple and it will be difficult to form a complex fracture network, which will affect the final fracturing effect. Therefore, integrated fracturing fluid with good performance is the focus of volumetric fracturing fluid research.

CN110003877A discloses a kind of clean and slippery water that resists high salinity, which uses an organic boron/zirconium composite cross-linking agent and a viscosity-changing and drag-reducing agent to cross-link to increase the viscosity.

CN111763511A discloses the preparation of an integrated self-crosslinking thickener modified polymer for fracturing and a liquid preparation method, which can be used to prepare slick water and suspended sand fracturing fluids. The thickener used is a high molecular polymer emulsion polymerized by inverse emulsion. The amount added in slick water is 0.06%-0.12%, and the amount added in suspended sand fracturing fluid is 1%-2%. The essence is to use Changes in polymer concentration are used to adjust the viscosity of slick water and suspended sand fracturing fluid.

CN113025302A discloses an integrated self-crosslinking fracturing fluid, which utilizes a self-crosslinking emulsion type fracturing fluid thickener and prepares aqueous solutions with different mass fractions as fracturing fluids, that is, 0.05%-0.4% thickener solutions are used as fracturing fluids. Slippery water fracturing fluid and 0.4%-2.0% thickener solution are used as suspended sand fracturing fluid, and the switching between slick water and suspended sand fracturing fluids is achieved by adjusting the dosage.

CN112375557A discloses an alcohol-soluble slippery water for fracturing, which is composed of 20.0-60.0% polyacrylamide polymer, 0.5%-4.0% nanoparticles, 0.1%-3% surfactant and organic alcohol.

CN112126419A discloses a continuously prepared suspension, including 1-10 parts of thickening agent, 1-5 parts of cross-linking agent, 900-1000 parts of water, and 20-60 parts of proppant.

CN111635749A discloses a slick water system that balances drag reduction and sand carrying, consisting of 0.02-0.3wt% instant associative polymer drag reducer, 0.01-0.1wt% nonionic surfactant and/or anionic surface It is composed of active agent, 0.1-2wt% clay stabilizer and water, and the viscosity is adjustable within the range of 20mPa·s.

CN111647106A discloses viscoelastic polymer emulsion-type slippery water and suspended sand liquid, which is produced by inverse emulsion polymerization. The nanoscale viscoelastic polymer emulsion is prepared, which overcomes the shortcoming of low copolymerization rate of existing associative monomers in the inverse emulsion polymerization process.

Under the same fracturing displacement conditions, the existing technology to improve suspended sand performance mainly relies on increasing the viscosity of the fracturing fluid: increasing the concentration of polymer drag reducing agent or thickening agent to increase viscosity, or increasing the viscosity at a certain polymer concentration. Cross-linking occurs with cross-linking agents to increase viscosity, or hydrophobically associating polymer-type drag reducing agents or thickening agents increase viscosity by relying on intramolecular and intermolecular association when the concentration reaches a certain level.

However, these existing technologies have at least the following problems: improving the sand suspension performance requires significantly increasing the concentration of drag reducing agent or thickening agent and supporting cross-linking agent concentration, and the fracturing fluid cost is high; under the same conditions, the viscosity of the fracturing fluid The higher the friction, the greater the friction, which leads to high friction under high viscosity conditions and increases the construction pump pressure; in order to improve the sand suspension performance, the viscosity of the fracturing fluid is greatly increased, and the viscosity of the fracturing fluid is too high, which will lead to fracturing. The fractures are relatively single, and the fracture network formed by fracturing is low in complexity, which affects the volume fracturing effect.

Contents of the invention

In order to solve the above technical problems, the object of the present invention is to provide an integrated fracturing fluid and a preparation method thereof. The integrated fracturing fluid provided by the present invention has the advantages of low friction, adjustable viscosity, and high sand suspension performance under the same viscosity condition.

In order to achieve the above object, the first aspect of the present invention provides an integrated fracturing fluid, which includes the following components in terms of mass percentage: 0.02%-0.5% drag reducing and thickening agent, 0.1%-0.5% nanometer Emulsion, 0.02%-0.1% first nonionic fluorocarbon surfactant, 0.003%-0.05% fungicide, 0-0.5% viscosity modifier, 0-0.5% clay stabilizer, 0-0.1% Gel breaker, 0.05%-0.2% modifier, 0.1%-1% gas generating agent, the balance is water.

According to the specific embodiment of the present invention, preferably, when the integrated fracturing fluid contains a viscosity modifier, based on the total mass of the integrated fracturing fluid being 100%, the content of the viscosity modifier is generally It can be controlled to 0.1%-0.5%.

According to the specific embodiment of the present invention, preferably, when the integrated fracturing fluid contains a gel breaker, based on the total mass of the integrated fracturing fluid being 100%, the content of the gel breaker is generally It can be controlled to 0.02%-0.1%.

According to the specific embodiment of the present invention, preferably, when the integrated fracturing fluid contains a clay stabilizer, based on the total mass of the integrated fracturing fluid being 100%, the content of the clay stabilizer is generally It can be controlled to 0.01%-0.5%.

According to a specific embodiment of the present invention, preferably, when the integrated fracturing fluid is a low-viscosity fracturing fluid (kinematic viscosity ≤ 5 mm ² /s), it includes the following components in terms of mass percentage: 0.02% - 0.05% drag-reducing tackifier, 0.1%-0.5% nanoemulsion, 0.02%-0.1% first non-ionic fluorocarbon surfactant, 0.003%-0.05% fungicide, 0-0.5% clay stabilization agent, 0.05%-0.2% modifier, 0.1%-0.5% gas generating agent, and the balance is water. More preferably, when the integrated fracturing fluid is a low-viscosity fracturing fluid, it includes the following components in terms of mass percentage: 0.03%-0.05% drag-reducing tackifier, 0.1%-0.4% nanometer Emulsion, 0.02%-0.08% first nonionic fluorocarbon surfactant, 0.005%-0.02% fungicide, 0.1%-0.3% clay stabilizer, 0.08%-0.15% modifier, 0.2%- 0.4% gas generating agent, the balance is water.

According to a specific embodiment of the present invention, preferably, when the integrated fracturing fluid is a medium-viscosity fracturing fluid (apparent viscosity is 12-30 mPa·s), it includes the following components in terms of mass percentage: 0.2 %-0.5% drag reducing tackifier, 0.1%-0.5% nanoemulsion, 0.02%-0.1% first non-ionic fluorocarbon surfactant, 0.003%-0.05% fungicide, 0-0.5% Clay stabilizer, 0.02%-0.1% gel breaker, 0.05%-0.2% modifier, 0.1%-0.5% gas generating agent, the balance is water. More preferably, when the integrated fracturing fluid is a medium-viscosity fracturing fluid, it includes the following components in terms of mass percentage: 0.2%-0.4% drag-reducing tackifier, 0.1%-0.4% nanometer Emulsion, 0.02%-0.08% first non-ionic fluorocarbon surfactant, 0.005%-0.02% fungicide, 0.1%-0.3% clay stabilizer, 0.02%-0.08% gel breaker, 0.08%- 0.15% modifier, 0.2%-0.4% gas generating agent, and the balance is water.

According to the specific embodiment of the present invention, preferably, when the integrated fracturing fluid is a high-viscosity fracturing fluid (apparent viscosity is 50-200 mPa·s), it includes the following components in terms of mass percentage: 0.3 %-0.5% drag reducing tackifier, 0.1%-0.5% nanoemulsion, 0.02%-0.1% first non-ionic fluorocarbon surfactant, 0.003%-0.05% fungicide, 0.1%-0.5% Viscosity regulator, 0-0.5% clay stabilizer, 0.06%-0.1% gel breaker, 0.05%-0.2% modifier, 0.1%-0.5% gas generating agent, the balance is water. More preferably, when the integrated fracturing fluid is a high-viscosity fracturing fluid, it includes the following components in terms of mass percentage: 0.3%-0.5% drag-reducing tackifier, 0.1%-0.4% nanometer Emulsion, 0.02%-0.08% first nonionic fluorocarbon surfactant, 0.005%-0.02% fungicide, 0.25%-0.45% viscosity modifier, 0.1%-0.3% clay stabilizer, 0.06%- 0.1% gel breaker, 0.08%-0.15% modifier, 0.2%-0.4% gas generating agent, the balance is water.

In the above-mentioned integrated fracturing fluid, preferably, the drag reducing and thickening agent is a mixture of hydrolyzed polyacrylamide and/or its derivatives and non-hydrolyzed polyacrylamide and/or its derivatives. More preferably, the mass ratio of the hydrolyzed polyacrylamide and/or its derivatives to the non-hydrolyzed polyacrylamide and/or its derivatives is (10-15):1.

In the above-mentioned integrated fracturing fluid, preferably, in the drag-reducing and thickening agent, the viscosity average molecular weight of the hydrolyzed polyacrylamide and/or its derivatives is 5 million to 15 million, and the degree of hydrolysis is 20 %-30%; the viscosity average molecular weight of the non-hydrolyzable polyacrylamide and/or its derivatives is 5 million-15 million.

The drag reducing and thickening agent used in the fracturing fluid of the present invention is a mixture of hydrolyzed polyacrylamide and/or its derivatives and non-hydrolyzed polyacrylamide and/or its derivatives. The mass ratio of the two is (10-15) : 1. The viscosity average molecular weight of both is 5 million-15 million. Hydrolyzed polyacrylamide contains a large number of carboxyl groups, which cross-link with the central ions of the cross-linking agent (i.e., the viscosity regulator of the present invention) at a certain concentration, thereby forming a network structure and greatly increasing the viscosity of the fracturing fluid. Rely on high viscosity to improve sand suspension performance. Compared with hydrolyzed polyacrylamide, the dosage concentration of non-hydrolyzed polyacrylamide is lower. At a certain concentration, no cross-linking reaction occurs with the central ion of the cross-linking agent (i.e., the viscosity regulator of the present invention), and the non-hydrolyzed polyacrylamide remains non-cross-linked. The linear polymer state stretches in the fracturing fluid, thereby ensuring that the fracturing fluid still has high resistance reduction under high viscosity conditions. Therefore, the present invention overcomes the contradiction between the low friction resistance and high suspended sand of the fracturing fluid by combining hydrolyzed polyacrylamide and/or its derivatives and non-hydrolyzed polyacrylamide and/or its derivatives in a specific ratio.

In the above-mentioned integrated fracturing fluid, preferably, the nanoemulsion is a nanoemulsion with an average particle size ≤150 nm.

In the above-mentioned integrated fracturing fluid, preferably, based on the total mass of the nanoemulsion being 100%, it includes the following components: 10%-20% fluorine-containing silicone oil, 5%-10% Gemini fluorine Carbon surfactant, 15%-25% of the second non-ionic fluorocarbon surfactant, 5%-10% of nano-silica, 1%-10% of lower alcohol, and the balance is water.

In the above-mentioned integrated fracturing fluid, preferably, in the nanoemulsion, the fluorine-containing silicone oil includes one of hydroxyfluorosilicone oil, vinyl fluorosilicone oil, methyl fluorosilicone oil, polyether fluorosilicone oil, etc., or A combination of several.

In the above integrated fracturing fluid, preferably in the nanoemulsion, the general structural formula of the gemini fluorocarbon surfactant is: C _n F _2n+1 N ⁺ (CH ₃ ) ₂ -CH ₂ CH ₂ CH ₂ CH ₂ -(CH ₃ ) ₂ N ⁺ C _n F _2n+1 , where n is 2-4.

More preferably, the gemini fluorocarbon surfactant is prepared by the following steps: add 1-3 parts of fluorine-containing brominated alkanes to the solvent at 20-40°C in parts by weight, stir and mix evenly. (The stirring speed is preferably 100-300 rpm), then add 0.5-1.5 parts of tetramethylbutanediamine dropwise (the dropping speed is preferably completed evenly within 10-20 minutes), and carry out the quaternization reaction under stirring (stirring The rotation speed is preferably 100-300 rpm). After the reaction for 0.5-2 hours, the precipitate obtained is the Gemini fluorocarbon surfactant. Among them, particularly preferably, the fluorine-containing brominated alkane includes one or a combination of heptafluoro-2-bromopropane, pentafluorobromoethane, 1-nonafluorobutyl bromide, and the like. The solvent may include acetone, etc., and its dosage may be 7-10 parts by weight. In addition, the precipitate obtained after the reaction can be subjected to conventional operations such as filtration and washing. The present invention does not impose special limitations on these conventional operations.

In the above-mentioned integrated fracturing fluid, preferably, in the nanoemulsion, the second non-ionic fluorocarbon surfactant includes polyoxyethylene ether of fluorine-containing fatty alcohol and polyoxyethylene ether of fluorine-containing phenol. , one or a combination of polyoxyethylene ethers containing fluorine-containing alkyl sulfonyl alcohol amines, polyoxyethylene esters containing fluorine-containing carboxylic acids, and polyoxyethylene ethers containing fluorine-containing thiols. More specifically, the second nonionic fluorocarbon surfactant includes but is not limited to: DuPont's nonionic fluorocarbon surfactant Capstone FS-30, Guangzhou Shunrun New Material Technology Co., Ltd.'s nonionic fluorocarbon surfactant Agent FCF-204, 3M Company's nonionic fluorocarbon surfactant FC4430, 3M Company's nonionic fluorocarbon surfactant FC4432, Sichuan Kehongda Group's nonionic fluorocarbon surfactant KHD011, Guangzhou Kanglun Xifluorosilicone Technology Co., Ltd. One of the company's KX-109 nonionic fluorocarbon surfactant, DuPont's nonionic fluorocarbon surfactant Capstone FS-3100, Anhui Jinao Chemical Co., Ltd.'s nonionic fluorocarbon surfactant AF4018-Y, etc. species or a combination of several species.

In the above-mentioned integrated fracturing fluid, preferably, in the nanoemulsion, the particle size of the nanosilica is 15-50 nm.

In the above-mentioned integrated fracturing fluid, preferably, in the nanoemulsion, the lower alcohol includes one or a combination of methanol, ethanol, propanol, butanol, and the like.

In the above-mentioned integrated fracturing fluid, preferably, the nanoemulsion is prepared by the following steps: according to the content of each component in the above-mentioned nanoemulsion, at a stirring speed of 10-40°C and 120-600rpm , add Gemini fluorocarbon surfactant and non-ionic fluorocarbon surfactant to the water, and then stir for 10-30 minutes; then add lower alcohol, and continue to stir for 10-30 minutes; then add nano-silica, and continue to stir for 10-30 minutes; then Fluorine-containing silicone oil is added dropwise, and stirring is continued for 30-60 minutes; finally, ultrasonic treatment is performed for 20-40 minutes to obtain the nanoemulsion. Wherein, more preferably, the frequency of the ultrasonic wave is 15-20 kilohertz. Wherein, the dripping speed of the fluorine-containing silicone oil is preferably 30 minutes to complete the dripping evenly.

The fracturing fluid of the present invention uses the above-mentioned nanoemulsion with an average droplet diameter of ≤150 nm, which can enter the fine cracks in the formation, play the role of gas-liquid replacement and improve formation imbibition, thereby improving the transformation effect.

In the above-mentioned integrated fracturing fluid, preferably, the first nonionic fluorocarbon surfactant includes polyoxyethylene ethers containing fluorine-containing fatty alcohols, polyoxyethylene ethers containing fluorine-containing phenols, and fluorine-containing alkylsulfonyl ethers. One or a combination of polyoxyethylene ethers of alcohol amines, polyoxyethylene esters of fluorine-containing carboxylic acids, and polyoxyethylene ethers of fluorine-containing mercaptans. More specifically, the first nonionic fluorocarbon surfactant includes but is not limited to: DuPont's nonionic fluorocarbon surfactant Capstone FS-30, Guangzhou Shunrun New Material Technology Co., Ltd.'s nonionic fluorocarbon surfactant Agent FCF-204, 3M Company's nonionic fluorocarbon surfactant FC4430, 3M Company's nonionic fluorocarbon surfactant FC4432, Sichuan Kehongda Group's nonionic fluorocarbon surfactant KHD011, Guangzhou Kanglun Xifluorosilicone Technology Co., Ltd. One of the company's KX-109 nonionic fluorocarbon surfactant, DuPont's nonionic fluorocarbon surfactant Capstone FS-3100, Anhui Jinao Chemical Co., Ltd.'s nonionic fluorocarbon surfactant AF4018-Y, etc. species or a combination of several species. The first nonionic fluorocarbon surfactant can synergize with the nanoemulsion of the present invention to jointly reduce the surface tension of the fracturing fluid and reduce the capillary resistance of the fracturing fluid flowing in the fine fractures of the formation.

In the above-mentioned integrated fracturing fluid, preferably, the bactericide includes one or a combination of aldehyde bactericides, quaternary ammonium salt bactericides, isothiazolinone bactericides, and the like.

In the above-mentioned integrated fracturing fluid, preferably, the aldehyde bactericide includes one or a combination of glutaraldehyde, formaldehyde, acrolein, and the like.

In the above-mentioned integrated fracturing fluid, preferably, the quaternary ammonium salt fungicides include tetradecyldimethylbenzylammonium chloride, dodecyltrimethylammonium chloride, dodecyl One or a combination of dimethylbenzylammonium chloride and dodecyldimethylbenzylammonium bromide.

In the above-mentioned integrated fracturing fluid, preferably, the isothiazolinone fungicide includes methylisothiazolinone and/or methylchloroisothiazolinone, etc.

The bactericide used in the fracturing fluid of the present invention can kill bacteria in the fracturing fluid and inhibit bacterial growth, thereby avoiding corrosion problems caused by bacterial growth and micro-crack clogging caused by bacterial metabolites.

In the above-mentioned integrated fracturing fluid, preferably, the viscosity modifier includes one or a combination of water-soluble zirconium salts, water-soluble titanium salts, water-soluble chromium salts, water-soluble aluminum salts, etc. More preferably, the viscosity modifier includes: water-soluble zirconium salt, water-soluble titanium salt, water-soluble chromium salt, water-soluble aluminum salt, etc., which are obtained by complex reaction with polyhydric alcohols respectively. One or a combination of titanium salts, water-soluble organic chromium salts, water-soluble organic aluminum salts, etc. The viscosity modifier used in the present invention can cross-link with the hydrolyzed polyacrylamide and/or its derivatives in the drag reducing and thickening agent of the present invention to significantly increase the viscosity of the fracturing fluid.

In the above-mentioned integrated fracturing fluid, preferably, the water-soluble organic zirconium salt includes zirconium oxychloride and sorbitol, glycerol, ethylene glycol, 1,2-propanediol, and 1,4-butanediol. The complex is obtained by one or more complex reactions among , diethylene glycol, triethylene glycol, etc. More specifically, in the complexation reaction, the dosage mass ratio of zirconium oxychloride and polyhydric alcohol can be (5-20): (80-95), and the complexation reaction temperature can be 50-90°C. , the reaction time can be 1-6h.

In the above-mentioned integrated fracturing fluid, preferably, the water-soluble organic titanium salt includes di(triethanolamine) diisopropyl titanate, tetraisopropyl orthotitanate, diisopropyl orthotitanate and bislactate. esters and diacetylacetonate diisopropyl orthotitanate, or a combination of several; or di(triethanolamine) diisopropyl titanate, tetraisopropyl orthotitanate, orthotitanic acid One or a combination of diisopropyl dilactate and diacetylacetone diisopropyl orthotitanate and sorbitol, glycerol, ethylene glycol, 1,2-propanediol, 1,4 -A complex obtained by a complex reaction of one or more combinations of butanediol, diethylene glycol, triethylene glycol, etc. More specifically, in the complexation reaction, di(triethanolamine) diisopropyl titanate, tetraisopropyl orthotitanate, diisopropyl orthotitanate lactate and diacetylacetone orthotitanate The dosage and mass ratio of one or several combinations of diisopropyl esters and the polyhydric alcohol can be (5-20): (80-95), the complexing reaction temperature can be 50-90°C, and the reaction time It can be 1-6h.

In the above-mentioned integrated fracturing fluid, preferably, the water-soluble organic chromium salt includes one or a combination of chromium lactate, chromium acetate, chromium chloride, chromium sulfate, etc., and sorbitol and glycerol. The complex is obtained by the combined complexation reaction of one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, diethylene glycol and triethylene glycol. More specifically, in the complexation reaction, the mass ratio of one or more combinations of chromium lactate, chromium acetate, chromium chloride, chromium sulfate, etc. to the polyhydric alcohol can be (10-20): (80-90), the complexing reaction temperature can be 50-90°C, and the reaction time can be 1-3h.

In the above integrated fracturing fluid, preferably, the water-soluble organic aluminum salt includes one or a combination of potassium aluminum sulfate dodecahydrate, aluminum sulfate, aluminum lactate, aluminum acetate, aluminum chloride, etc. With sorbitol, glycerol, ethylene glycol The complex is obtained by the combined complexation reaction of one or more of alcohol, 1,2-propanediol, 1,4-butanediol, diethylene glycol, triethylene glycol, etc. More specifically, in the complexation reaction, the dosage mass ratio of one or more combinations of potassium aluminum sulfate dodecahydrate, aluminum sulfate, aluminum lactate, aluminum acetate, aluminum chloride, etc. and the polyhydric alcohol can be It is (15-25): (75-85), the complexing reaction temperature can be 50-90°C, and the reaction time can be 1-3h.

In the above-mentioned integrated fracturing fluid, preferably, the clay stabilizer includes one or a combination of tetramethylammonium chloride, potassium chloride, polyquaternium salt, and the like.

In the above-mentioned integrated fracturing fluid, preferably, the gel breaker includes one or a combination of ammonium persulfate, sodium persulfate, potassium persulfate, etc. The gel breaker used in the present invention can break and degrade the drag-reducing tackifier and the jelly produced by cross-linking the drag-reducing tackifier and the viscosity modifier through its oxidation, so as to reduce the viscosity of the polymer to the formation. Attaches blockage damage.

In the above-mentioned integrated fracturing fluid, preferably, the modifier includes a silane modifier. More preferably, the silane modifier includes N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane and N-β-aminoethyl - One or a combination of γ-aminopropyltrimethoxysilane, etc. The modifier used in the present invention can be adsorbed on the surface of sand (i.e. ceramsite and/or quartz sand, etc.) during the fracturing process, changing the surface of the sand from hydrophilic and oil-increasing to oleophilic and hydrophobic, thereby adsorbing the pressure The dissolved gas in the fracturing fluid and/or the gas generated by the gas generating agent of the present invention causes the adsorbed gas to surround the surface of the sand, thereby suspending the sand in the fracturing fluid.

In the above-mentioned integrated fracturing fluid, preferably, the gas generating agent includes effervescent tablet particles and the like. More preferably, the effervescent tablet particles are those in which the acid source is citric acid, the alkali source is sodium bicarbonate, and polyethylene glycol is a capsule coating. Particularly preferably, the gas generating agent is prepared by the following steps: dissolving polyethylene glycol (preferably PEG-6000) in water (the temperature of the water can be 80-90°C) to form a viscous substance (the The mass fraction of polyethylene glycol in the viscous material is 60%-90%), divided into two parts (the mass ratio of the two divided viscous materials can be 1:1-1:1.8); add citric acid, hydrogen carbonate Sodium is mixed with the two divided parts of the viscous material respectively (the mass ratio of citric acid and the viscous material can be 1:1-1:1.2, and the mass ratio of sodium bicarbonate and the viscous material can be 1:1-1:1.2 ), stir evenly, dry (the drying temperature can be 30-45°C), and then pulverize into powder to obtain acid source powder and alkali source powder respectively; add poly(polymer) to the acid source powder and alkali source powder respectively. Ethylene glycol (preferably PEG-800) (based on the total weight of acid source powder and polyethylene glycol being 100%, the amount of polyethylene glycol added in this step can be 3%-8%; based on alkali source powder and The total weight of polyethylene glycol is 100%, the amount of polyethylene glycol in this step can be 3%-8%), mix evenly, and obtain acid source viscosity and alkali source viscosity respectively; The acid source viscosity, the alkali source viscosity, and polyethylene glycol (preferably PEG-6000) are mixed according to a weight ratio of (1-2): (1-2.5): (0.1-0.2), After mixing evenly, tableting and granulating (and/or crushing) are performed to obtain effervescent tablet particles, which are the gas generating agents.

The gas generating agent used in the present invention can gradually dissolve the polyethylene glycol coating in the fracturing fluid by stirring, thereby When the acid source and the alkali source come into contact in the fracturing fluid, the acid-base reaction releases carbon dioxide gas, which is adsorbed around the surface of the sand by the sand with the modifier adsorbed on the surface, thereby suspending the sand in the fracturing fluid.

A second aspect of the present invention provides a method for preparing the above-mentioned integrated fracturing fluid, which includes the following steps:

When preparing indoors:

S1. Under stirring conditions of 60-200 rpm, based on the total mass of the integrated fracturing fluid being 100%, add 0.02%-0.5% drag reducing and thickening agent to water (the amount of water is equal to Add the amounts of other components to make up 100% (calculated), stir and mix evenly;

S2. Then add 0.003%-0.05% fungicide, 0-0.5% clay stabilizer, 0.05%-0.2% modifier, 0.1%-0.5% nanoemulsion, 0.02%-0.1% first non- ionic fluorocarbon surfactant, stir and mix evenly to obtain the first mixed liquid;

S3. According to the viscosity requirements of the required fracturing fluid, add 0-0.5% viscosity modifier to the first mixed liquid, stir and mix evenly, and obtain the second mixed liquid;

S4. Add 0.1%-1% gas generating agent and 0-0.1% gel breaker to the second mixed liquid, stir evenly, and obtain the integrated fracturing fluid (when the fracturing fluid of the present invention When the components of the liquid do not contain a viscosity modifier, then a gas generating agent and an optional gel breaker are added to the first mixed liquid);

When prepared on site:

The preparation steps of S1-S3 are the same as those in indoor preparation. The preparation steps of S4 are: add 0.1%-1% gas generating agent and 0-0.1% gel breaker into the sand mixing tank of the sand mixing truck, and mix with the above The second mixed liquid and sand are mixed evenly in the sand mixing tank of the sand mixing truck.

In the preparation method of the present invention, when the integrated fracturing fluid of the present invention is a low-viscosity fracturing fluid, a medium-viscosity fracturing fluid, or a high-viscosity fracturing fluid, the dosage of each component has been explained above. Without going into details, those skilled in the art should understand that the fracturing fluid is configured according to the amounts of each component in the fracturing fluids of different viscosities and the above preparation method of the present invention.

The integrated fracturing fluid provided by the present invention has the following advantages and beneficial effects:

At the same viscosity, the fracturing fluid provided by the present invention has lower friction resistance than conventional fracturing fluid, and the friction reduction rate is increased by 2.1-11.2 percentage points, and the higher the viscosity, the greater the improvement in the drag reduction rate. At the same time, the fracturing fluid provided by the present invention has better sand-suspending performance than conventional fracturing fluids of the same viscosity: under low-viscosity conditions, the fracturing fluid provided by the present invention begins to settle after 20 seconds of suspended sand, half of which settles in 3 minutes, and completely settles in 10 minutes. , while the conventional slick water fracturing fluid suspended sand of the same/similar viscosity begins to settle in 0s and completely settles in 10s; under medium viscosity conditions, the fracturing fluid suspended sand provided by the present invention begins to settle after 1 minute, and half of the sedimentation occurs in 5 minutes. There is no obvious continued settlement phenomenon at the 10th minute, while the conventional linear glue fracturing fluid suspension sand of the same/similar viscosity begins to settle in 2s, half settles in 20s, and completely settles in 1min; under high viscosity conditions, this The fracturing fluid suspended sand provided by the invention has no obvious settlement within 10 minutes, while the conventional jelly fracturing fluid suspended sand with the same/similar viscosity settles by 10% in 10 minutes. Therefore, the integrated fracturing fluid provided by the present invention has the advantages of low friction, adjustable viscosity, and high sand suspension performance under the same viscosity condition.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solutions of the present invention are described in detail below, but this should not be understood as limiting the implementable scope of the present invention.

Example 1

This embodiment provides an integrated fracturing fluid, which includes the following components in terms of mass percentage: 0.03% drag-reducing tackifier, 0.1% nanoemulsion, 0.02% non-ionic fluorocarbon surfactant, 0.005% sterilization agent, 0.2% clay stabilizer, 0.08% modifier, 0.2% gas generating agent, and the balance is water.

Wherein, the drag-reducing tackifier is a mixture of polyacrylamide with a viscosity average molecular weight of 9.8 million and a hydrolysis degree of 22% and a non-hydrolyzable polyacrylamide with a viscosity average molecular weight of 10 million ± 1 million. The mass ratio of the two is 12:1.

The nanoemulsion is a nanoemulsion with an average particle size of 100 nm. Based on the total mass of the nanoemulsion being 100%, it includes: 15% methyl fluorosilicone oil (Guangzhou Daxi Chemical Raw Materials Co., Ltd., 8012-300), 6% Gemini fluorocarbon surfactant C ₃ F ₇ N ⁺ (CH ₃ ) ₂ -CH ₂ CH ₂ CH ₂ CH ₂ -(CH ₃ ) ₂ N ⁺ C ₃ F ₇ (Homemade: In parts by weight, at 25°C, add 2 parts of heptafluoro-2-bromopropane to Mix 8 parts of acetone evenly with stirring at 200rpm, then add 1 part of tetramethylbutanediamine dropwise, and add it evenly for 10 minutes. Perform quaternization reaction with stirring at 200rpm. After 1 hour of reaction, filter the precipitate and obtain the precipitate. That is, the prepared Gemini fluorocarbon surfactant), 22% nonionic fluorocarbon surfactant (DuPont, Capstone FS-30), 6% nanosilica with an average particle size of 20nm, 5% methanol and the balance water.

The nanoemulsion is prepared by the following steps: according to the content of each component in the above-mentioned nanoemulsion, water is added to the reaction kettle, and the Gemini fluorocarbon surfactant C ₃ F is added at a stirring speed of 35°C and 300rpm. ₇ N ⁺ (CH ₃ ) ₂ -CH ₂ CH ₂ CH ₂ CH ₂ -(CH ₃ ) ₂ N ⁺ C ₃ F _7. Add nonionic fluorocarbon surfactant to the reaction kettle, stir for 20 minutes; then add methanol and continue Stir for 20 minutes; then add nano-silica and continue to stir for 20 minutes; add methylfluorosilicone oil dropwise at the speed of 30 minutes of completion, and continue to stir for 40 minutes; finally, use ultrasonic treatment with a frequency of 20 kilohertz for 30 minutes to obtain the nanoemulsion .

The non-ionic fluorocarbon surfactant is DuPont's Capstone FS-30.

The bactericide is glutaraldehyde.

The clay stabilizer is tetramethylammonium chloride.

The modifier is N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane (Wuhan Xinweiye Chemical Co., Ltd.).

The gas generating agent is an effervescent tablet particle whose acid source is citric acid, alkali source is sodium bicarbonate, and polyethylene glycol is a capsule coating. It is prepared through the following steps: dissolve polyethylene glycol (PEG-6000) in hot water at 80-90°C to form a viscous substance. The mass of polyethylene glycol (PEG-6000) in the viscous substance is The fraction is 60%-90%, divided into two parts (the mass ratio of the two divided parts of the viscous material is 1:1); mix citric acid and sodium bicarbonate with the two divided parts of the viscous material respectively, and the citric acid and the viscous material are mixed. The mixing mass ratio of the thick substance is 1:1-1:1.2, and the mixing mass ratio of sodium bicarbonate and the sticky substance is 1:1-1:1.2. After stirring evenly, dry it at 30-45°C and then grind it into powder. , obtain acid source powder and alkali source powder respectively; add polyethylene glycol (PEG-800) to the acid source powder and the alkali source powder respectively, and use the acid source powder and polyethylene glycol (PEG-800) Based on the total weight of 100%, the addition amount of polyethylene glycol (PEG-800) is 3%-8%, based on the total weight of alkali source powder and polyethylene glycol (PEG-800) is 100%, the amount of polyethylene glycol (PEG-800) is 100%. The addition amount of ethylene glycol (PEG-800) is 3%-8%, mix evenly, and obtain acid source viscosity and alkali source viscosity respectively; combine the acid source viscosity and the alkali source viscosity The mixture and polyethylene glycol (PEG-6000) are mixed according to the weight ratio of 2:1:0.1. After mixing evenly, the mixture is tableted, granulated and pulverized to obtain effervescent tablet particles.

The preparation method of the integrated fracturing fluid in this embodiment includes the following steps: under the stirring condition of 100 rpm, slowly add 0.03% of the drag-reducing viscosity increasing agent into the water, stir and mix evenly; then add 0.005% of the said drag-reducing tackifier in sequence. The fungicide, 0.2% of the clay stabilizer, 0.08% of the modifier, 0.1% of the nanoemulsion, and 0.02% of the non-ionic fluorocarbon surfactant, stir and mix evenly; finally add 0.2% of the product aerosol and stir evenly to obtain the integrated fracturing fluid. The integrated fracturing fluid obtained in Example 1 is a low-viscosity slick water fracturing fluid.

Comparative example 1-1

The nanoemulsion was removed from the fracturing fluid components in Example 1, and the remaining components and contents as well as the fracturing fluid preparation method were the same to obtain the fracturing fluid of Comparative Example 1-1. The fracturing fluid obtained in Comparative Example 1-1 is a low-viscosity slick water fracturing fluid.

Comparative Example 1-2

The nanoemulsion was replaced in the fracturing fluid components of Example 1, and the remaining components and contents as well as the fracturing fluid preparation method were the same to obtain the fracturing fluid of Comparative Example 1-2. The fracturing fluid obtained in Comparative Example 1-2 is a low-viscosity slick water fracturing fluid.

The replaced nanoemulsion does not contain the gemini fluorocarbon surfactant C ₃ F ₇ N ⁺ (CH ₃ ) ₂ -CH ₂ CH ₂ CH ₂ CH ₂ -(CH ₃ ) ₂ N ⁺ C ₃ F ₇ , and other components are The content is the same as in Example 1. It is prepared through the following steps: according to the content of each component in the above-mentioned nanoemulsion, add water to the reaction kettle, and add non-ionic fluorocarbon surfactant (DuPont, Capstone FS) at 35°C and 300 rpm stirring speed. -30) Add to the reaction kettle and stir for 20 minutes; then add methanol and continue to stir for 20 minutes; then add nano-silica and continue to stir for 20 minutes; add methylfluorosilicone oil dropwise at the speed of 30 minutes of completion of the dropwise addition, and continue to stir for 40 minutes to obtain the result The nanoemulsion mentioned above.

Conventional slick water fracturing fluid A:

Taking the total mass of the conventional slick water fracturing fluid A as 100%, its viscosity average molecular weight from 0.1% is 9.9 million. The degree of hydrolysis is 25% polyacrylamide emulsion (Chengdu Dute Technology Development Co., Ltd., CT1-20D), 0.1% drainage aid (Chengdu Dute Technology Development Co., Ltd., CT5-12), 0.005% fungicide (Chengdu Dute Technology Development Co., Ltd., CT5-12) Special Technology Development Co., Ltd., CT10-4) and the remaining amount of water, prepared.

Conventional slick water fracturing fluid B:

Taking the total mass of the conventional slick water fracturing fluid B as 100%, it consists of 0.03% hydrophobically associated polymer powder with a viscosity average molecular weight of 8.8 million (Chengdu Dute Technology Development Co., Ltd., CT1-20B), It is formulated with 0.1% drainage aid (Chengdu Dute Technology Development Co., Ltd., CT5-12), 0.005% fungicide (Chengdu Dute Technology Development Co., Ltd., CT10-4) and the remaining amount of water.

The fracturing fluid prepared in Example 1 and Comparative Examples 1-1 and 1-2 has low viscosity, and the main performance of the fracturing fluid is in accordance with the industry standard NB/T 14003.1-2015 "Shale Gas Fracturing Fluid Part 1: Slippery" Water performance indicators and evaluation methods" testing. The test results of the main properties of fracturing fluid are shown in Table 1.

Table 1 Main properties of fracturing fluids in Example 1 and Comparative Examples 1-1 and 1-2

The suspended sand performance test is carried out according to the following steps: respectively add 500 mL of Example 1 fracturing fluid, Comparative Example 1-1 fracturing fluid, Comparative Example 1-2 fracturing fluid, conventional slick water fracturing fluid A, and conventional slick water pressure Pour the cracking liquid B into the Wu Yin mixer, add 150g of 40-70 mesh ceramsite into the Wu Yin mixer, stir for 2 minutes at a stirring speed of 500 rpm, and then pour it all into a 1000 mL measuring cylinder. Start Timing, recording the settlement of ceramsite, and characterizing the sand suspension performance of the fracturing fluid. The slower the ceramsite settles, the better the sand suspension performance of the fracturing fluid is. The test results of suspended sand performance are shown in Table 2.

Table 2 Fracturing fluid sand suspension performance of Example 1 and Comparative Examples 1-1 and 1-2

It can be seen from the above Table 1 and Table 2 that compared with Example 1, the discharge rate of Comparative Example 1-1 is significantly reduced (62% to 42%) after removing the nanoemulsion from the fracturing fluid formula, indicating that Example 1 The nanoemulsion in it can improve the flow performance of fracturing fluid in fine cracks through dialysis and other effects, and increase the flowback rate, which is very beneficial to reducing damage to fracturing fluid; other properties have not changed significantly.

Comparative Example 1-2 Compared with Example 1, after replacing the nanoemulsion composition in the fracturing fluid formula (removing the gemini fluorocarbon surfactant and removing the ultrasonic treatment), the discharge rate was significantly reduced (62% to 45%) , indicating that the nanoemulsion in Example 1 can improve the flow performance of fracturing fluid in fine cracks through dialysis and other effects, and increase the flowback rate, which is very beneficial to reducing damage to fracturing fluid; other properties have not changed significantly; for The nanoemulsion in Ratio 1-2 cannot achieve the same effect as the nanoemulsion in Example 1.

Compared with Example 1, the drag reduction rates of conventional slick water fracturing fluids A and B were reduced by 2.1 percentage points and 10.1 percentage points respectively, while the suspended sand performance of Example 1 started to settle after 20 seconds, half of which settled in 3 minutes, and half settled in 10 minutes. Complete settlement" changed to "Start settling in 0s and completely settle in 10s", indicating that the fracturing fluid of Example 1 improved the drag reduction performance of the low-viscosity slick water fracturing fluid and greatly improved the suspension resistance of the low-viscosity slick water fracturing fluid. Sand performance.

Example 2

This embodiment provides an integrated fracturing fluid, which includes the following components in terms of mass percentage: 0.2% drag-reducing tackifier, 0.2% nanoemulsion, 0.03% non-ionic fluorocarbon surfactant, 0.004% sterilization agent, 0.2% clay stabilizer, 0.02% gel breaker, 0.1% modifier, 0.3% gas generating agent, and the balance is water.

Wherein, the drag-reducing tackifier is a mixture of polyacrylamide with a viscosity average molecular weight of 11.7 million and a hydrolysis degree of 28% and a non-hydrolyzable polyacrylamide with a viscosity average molecular weight of 11.5 million. The mass ratio of the two is 14: 1.

The nanoemulsion is a nanoemulsion with an average particle size of 130 nm. Based on the total mass of the nanoemulsion being 100%, it includes: 18% hydroxyfluorosilicone oil (Wuhan Rongcan Biotechnology Co., Ltd.), 7% Gemini fluorocarbon surfactant C ₂ F ₅ N ⁺ (CH ₃ ) ₂ -CH ₂ CH ₂ CH ₂ CH ₂ -(CH ₃ ) ₂ N ⁺ C ₂ F ₅ (Homemade: In parts by weight, at 30°C, add 1.5 parts of pentafluorobromoethane to 7 parts of acetone, at 150 rpm Mix evenly while stirring, then add 1 part of tetramethylbutanediamine dropwise, and add it evenly for 12 minutes. Perform quaternization reaction under stirring at 150 rpm. After 1.5 hours of reaction, filter and precipitate. The resulting precipitate is the prepared gemini fluorine. carbon surfactant), 20% nonionic fluorocarbon surfactant (Guangzhou Shunrun New Material Technology Co., Ltd., FCF-204), 5% nanosilica with an average particle size of 20nm, 7% ethanol and the balance water.

The nanoemulsion is prepared by the following steps: the content of each component in the nanoemulsion mentioned above is added to the reaction kettle, and the gemini fluorocarbon surfactant C ₂ F ₅ is mixed at 35° C. and a stirring speed of 300 rpm. N ⁺ (CH ₃ ) ₂ -CH ₂ CH ₂ CH ₂ CH ₂ -(CH ₃ ) ₂ N ⁺ C ₂ F _5. Add nonionic fluorocarbon surfactant to the reaction kettle and stir for 30 minutes; then add ethanol and continue stirring. 15 minutes; then add nano-silica and continue stirring for 20 minutes; add hydroxyfluorosilicone oil dropwise at the speed of uniform dripping for 30 minutes and continue stirring for 45 minutes; finally, use ultrasonic treatment with a frequency of 16 kilohertz for 30 minutes to obtain the nanoemulsion.

The non-ionic fluorocarbon surfactant is FCF-204 from Guangzhou Shunrun New Material Technology Co., Ltd.

The fungicide is dodecyltrimethylammonium chloride.

The clay stabilizer is polyquaternary ammonium salt.

The gel breaker is potassium persulfate.

The modifier is 3-aminopropyltriethoxysilane.

The gas generating agent is an effervescent tablet particle in which the acid source is citric acid, the alkali source is sodium bicarbonate, and polyethylene glycol is a capsule coating. The specific preparation steps are the same as in Example 1.

The preparation method of the integrated fracturing fluid in this embodiment includes the following steps: under the stirring condition of 150 rpm, slowly add 0.2% of the drag-reducing tackifier to the water, stir and mix evenly; then add 0.004% of the The fungicide, 0.2% of the clay stabilizer, 0.1% of the modifier, 0.2% of the nanoemulsion, and 0.03% of the non-ionic fluorocarbon surfactant, stir and mix evenly; finally add 0.3% of the product The aerosol and 0.02% of the gel breaker are mixed evenly to obtain the integrated fracturing fluid. The integrated fracturing fluid obtained in Example 2 belongs to the medium-viscosity linear fracturing fluid.

Comparative example 2

The modifier and gas generating agent were removed from the fracturing fluid components of Example 2, and the remaining components and contents as well as the fracturing fluid preparation method were the same to obtain the fracturing fluid of Comparative Example 2. The fracturing fluid obtained in Comparative Example 2 belongs to the medium-viscosity linear glue fracturing fluid.

Conventional linear glue fracturing fluid C:

Based on the total mass of the conventional linear glue fracturing fluid C being 100%, it consists of 0.4% polyacrylamide emulsion with a viscosity average molecular weight of 9.9 million and a degree of hydrolysis of 25% (Chengdu Dute Technology Development Co., Ltd., CT1- 20D), 0.1% drainage aid (Chengdu Dute Technology Development Co., Ltd., CT5-12), 0.005% fungicide (Chengdu Dute Technology Development Co., Ltd., CT10-4) and the remaining amount of water.

Conventional linear glue fracturing fluid D:

Taking the total mass of the conventional linear glue fracturing fluid D as 100%, it consists of 0.25% hydrophobically associated polymer powder with a viscosity average molecular weight of 8.8 million (Chengdu Dute Technology Development Co., Ltd., CT1-20B), 0.1% drainage aid (Chengdu Dute Technology Development Co., Ltd., CT5-12), 0.005% fungicide (Chengdu Dute Technology Development Co., Ltd., CT10-4) and the remaining amount of water, prepared.

The fracturing fluid prepared in Example 2 and Comparative Example 2 is a medium viscosity fracturing fluid. The main performance of the fracturing fluid is in accordance with the industry standard NB/T 14003.3-2017 "Shale Gas Fracturing Fluid Part 3: Continuous Mixing Fracturing Fluid Performance Indicators and Evaluation Methods" was tested, and bacterial content was tested in accordance with the industry standard NB/T 14003.1-2015 "Shale Gas Fracturing Fluid Part 1: Slippery Water Performance Indicators and Evaluation Methods". The test results of the main properties of fracturing fluid are shown in Table 3. The suspended sand performance test was performed according to the test method of Example 1, and the test results are shown in Table 4.

Table 3 Main properties of fracturing fluids in Example 2 and Comparative Example 2

Table 4 Fracturing fluid sand suspension properties of Example 2 and Comparative Example 2

It can be seen from the above Table 3 and Table 4 that compared with Example 2, Comparative Example 2, after removing the modifier and gas generating agent from the fracturing fluid formula, the discharge rate dropped from 55% to 45%, indicating that Example 2 The modifiers and gas-generating agents in the fracturing fluid can increase energy by generating gas, improve the flow performance of the fracturing fluid in fine fractures, and increase the flowback rate; at the same time, the modifiers and gas-generating agents in the fracturing fluid formula of Comparative Example 2 are removed. After aerosolization, the suspended sand performance is from "Start settling after 1 minute and settle after 5 minutes" in Example 2. Half, there was no obvious continued settlement phenomenon from 5 minutes to 10 minutes" changed to "Start settling after 2 seconds, half settled in 30 seconds, and completely settled in 90 seconds", indicating that the fracturing fluid of Example 2 has greatly improved the performance of the medium-viscosity linear glue fracturing fluid. The sand suspension performance; other properties have no significant changes.

Compared with Example 2, conventional linear glue fracturing fluids C and D have reduced drag reduction rates of 7.3 percentage points and 2.3 percentage points respectively, while the suspended sand performance has changed from "Starting to settle after 1 minute, half settling after 5 minutes," as in Example 2. "No obvious continued settlement phenomenon from 5 minutes to 10 minutes" changed to "Start settling in 2 seconds, half settled in 20 seconds, and completely settled in 1 minute", indicating that the fracturing fluid of Example 2 improved the drag reduction performance of the medium viscosity linear glue fracturing fluid. , which greatly improves the sand suspension performance of medium-viscosity linear adhesive fracturing fluid.

Example 3

This embodiment provides an integrated fracturing fluid, which includes the following components in terms of mass percentage: 0.3% drag-reducing tackifier, 0.3% nanoemulsion, 0.05% non-ionic fluorocarbon surfactant, 0.01% sterilization agent, 0.3% viscosity regulator, 0.2% clay stabilizer, 0.08% gel breaker, 0.15% modifier, 0.2% gas generating agent, and the balance is water.

Wherein, the drag-reducing tackifier is a mixture of polyacrylamide with a viscosity average molecular weight of 8.1 million and a hydrolysis degree of 22% and a non-hydrolyzable polyacrylamide with a viscosity average molecular weight of 780. The mass ratio of the two is 10:1. .

The nanoemulsion is a nanoemulsion with an average particle size of 130 nm. Based on the total mass of the nanoemulsion being 100%, it includes: 15% vinyl fluorosilicone oil (Guangzhou Kangxi Silicone Materials Co., Ltd., KX-205), 5% Gemini fluorocarbon surfactant C ₂ F ₅ N ⁺ (CH ₃ ) ₂ -CH ₂ CH ₂ CH ₂ CH ₂ -(CH ₃ ) ₂ N ⁺ C ₂ F ₅ (Homemade: In parts by weight, at 30°C, add 1.5 parts of pentafluorobromoethane to 7 part of acetone, mix evenly with stirring at 150 rpm, then add 1 part of tetramethylbutanediamine dropwise, and add it evenly and completely in 12 min. Perform quaternization reaction with stirring at 150 rpm. After 1.5 h of reaction, filter the precipitate and obtain the precipitate. That is, the prepared Gemini fluorocarbon surfactant), 20% non-ionic fluorocarbon surfactant (3M Company, FC4430), 5% nano-silica with an average particle size of 30 nm, 9% propanol and the balance water.

The nanoemulsion is prepared by the following steps: according to the content of each component in the nanoemulsion mentioned above, water is added to the reaction kettle, and the gemini fluorocarbon surfactant C ₂ F is added at a stirring speed of 30°C and 300rpm. ₅ N ⁺ (CH ₃ ) ₂ -CH ₂ CH ₂ CH ₂ CH ₂ -(CH ₃ ) ₂ N ⁺ C ₂ F _5. Add nonionic fluorocarbon surfactant to the reaction kettle and stir for 15 minutes; then add propanol, Continue to stir for 20 minutes; then add nano-silica and continue to stir for 25 minutes; add vinyl fluorosilicone oil dropwise at the speed of evenly dropping for 30 minutes, and continue to stir for 40 minutes; finally, use ultrasonic treatment with a frequency of 18 kilohertz for 25 minutes to obtain the above of nanoemulsions.

The nonionic fluorocarbon surfactant is FC4430 from 3M Company.

The fungicide is methylisothiazolinone.

The viscosity regulator is a complex obtained by the complex reaction of zirconium oxychloride and sorbitol. It is made through the following steps What is prepared: According to the weight ratio of zirconium oxychloride: sorbitol: water is 20:50:30, zirconium oxychloride, sorbitol and water are mixed and complexed at 60°C for 1 hour to obtain the viscosity adjustment agent.

The clay stabilizer is potassium chloride.

The gel breaker is ammonium persulfate.

The modifier is N-β-aminoethyl-γ-aminopropyltrimethoxysilane.

The preparation method of the integrated fracturing fluid in this embodiment includes the following steps: under the stirring condition of 150 rpm, slowly add 0.3% of the drag-reducing tackifier to the water, stir and mix evenly; then add 0.01% of the The fungicide, 0.2% of the clay stabilizer, 0.15% of the modifier, 0.3% of the nanoemulsion, and 0.05% of the non-ionic fluorocarbon surfactant, stir and mix evenly; then add 0.3% of the viscosity regulator, stir and mix evenly; finally add 0.2% of the gas generating agent and 0.08% of the gel breaker, stir evenly to obtain the integrated fracturing fluid. The integrated fracturing fluid obtained in Example 3 is a high-viscosity jelly fracturing fluid.

Comparative example 3-1

In the fracturing fluid components of Example 3, all 0.3% of the drag-reducing and viscosity-increasing agents were replaced with hydrolyzed polyacrylamide with a molecular weight of 8.1 million and a hydrolysis degree of 22% (no non-hydrolyzable polyacrylamide). The remaining components and contents The fracturing fluid preparation method is the same, and the fracturing fluid of Comparative Example 3-1 is obtained. The fracturing fluid obtained in Comparative Example 3-1 is a high-viscosity jelly fracturing fluid.

Comparative Example 3-2

In the fracturing fluid components of Example 3, the mass percentage of the drag-reducing and thickening agent in the fracturing fluid was replaced with 0.7%, and the remaining components and contents and the fracturing fluid preparation method were the same to obtain Comparative Example 3-2. Fracturing fluid. The fracturing fluid obtained in Comparative Example 3-2 is a high-viscosity jelly fracturing fluid.

Conventional gel fracturing fluid E:

Based on the total mass of the conventional gel fracturing fluid E being 100%, it consists of 0.4% polyacrylamide emulsion (Chengdu Dute Technology Development Co., Ltd., CT1- 20D), 0.1% drainage aid (Chengdu Dute Technology Development Co., Ltd., CT5-12), 0.005% fungicide (Chengdu Dute Technology Development Co., Ltd., CT10-4), 0.4% organic zirconium cross-linking agent (the Same as the viscosity modifier in Example 3) and the remaining amount of water.

Conventional gel fracturing fluid F:

Based on the total mass of the conventional gel fracturing fluid F being 100%, it consists of 0.25% hydrophobically associated polymer powder with a viscosity average molecular weight of 8.8 million (Chengdu Dute Technology Development Co., Ltd., CT1-20B), 0.1% drainage aid (Chengdu Dute Technology Development Co., Ltd., CT5-12), 0.005% fungicide (Chengdu Dute Technology Development Co., Ltd., CT10-4), 0.4% organic zirconium cross-linking agent (which is the same as the viscosity modifier in Example 3) and the remaining amount of water.

The fracturing fluid prepared in Example 3 and Comparative Examples 3-1 and 3-2 is a high-viscosity fracturing fluid. The main performance of the fracturing fluid is in accordance with the industry standard NB/T 14003.3-2017 "Shale Gas Fracturing Fluid No. Part 3: Continuously Mixed Fracturing Fluid Performance Indicators and Evaluation Methods" was tested, and bacterial content was tested in accordance with the industry standard NB/T 14003.1-2015 "Shale Gas Fracturing Fluids Part 1: Slippery Water Performance Indicators and Evaluation Methods". The test results of the main properties of fracturing fluid are shown in Table 5. The suspended sand performance test was performed according to the test method of Example 1, and the test results are shown in Table 6.

Table 5 Main properties of fracturing fluids in Example 3 and Comparative Examples 3-1 and 3-2

Table 6 Fracturing fluid sand suspension performance of Example 3 and Comparative Examples 3-1 and 3-2

It can be seen from the above Table 5 and Table 6 that compared with Example 3, Comparative Example 3-1 has a lower drag-reducing and viscosity-increasing agent after all the fracturing fluid formulas are replaced with hydrolyzed polyacrylamide (no non-hydrolyzable polyacrylamide). The resistivity dropped from 71.2% to 61.1%, It shows that in Example 3, non-hydrolyzable polyacrylamide does not participate in cross-linking and can maintain a linear polymer state, thereby ensuring a high resistance reduction rate, while hydrolyzable polyacrylamide participates in cross-linking and forms a spatial network structure, which reduces the resistance reduction rate. ;Other performance has no significant changes.

Compared with Example 3, Comparative Example 3-2 showed that after the concentration of the drag-reducing tackifier in the fracturing fluid formula was increased to 0.7%, the drag-reducing rate dropped from 71.2% to 35.1%, and it could not be crushed after gelatinization. The overall jelly-like state is restored, indicating that too high a concentration of drag-reducing tackifier will lead to over-cross-linking, brittle colloid, increased fracturing fluid friction, and reduced drag-reducing rate.

Compared with Example 3, the drag reduction rates of conventional gel fracturing fluids E and F were reduced by 11.2 percentage points and 6.2 percentage points respectively, while the sand suspension performance changed from "no obvious settlement phenomenon within 10 minutes" in Example 3 to "10% of the ceramsite settles in 10 minutes" indicates that Example 3 greatly improves the drag reduction performance and sand suspension performance of the high-viscosity jelly fracturing fluid.

Example 4

This embodiment provides an integrated fracturing fluid, which includes the following components in terms of mass percentage: 0.4% drag-reducing tackifier, 0.4% nanoemulsion, 0.08% non-ionic fluorocarbon surfactant, 0.03% sterilization agent, 0.3% viscosity regulator, 0.4% clay stabilizer, 0.1% gel breaker, 0.15% modifier, 0.3% gas generating agent, and the balance is water.

Among them, the drag-reducing tackifier is a mixture of polyacrylamide with a viscosity average molecular weight of 12.1 million and a hydrolysis degree of 30% and a non-hydrolyzable polyacrylamide with a viscosity average molecular weight of 1140. The mass ratio of the two is 13:1. .

The nanoemulsion is a nanoemulsion with an average particle size of 150 nm. Based on the total mass of the nanoemulsion being 100%, it includes: 8% hydroxyfluorosilicone oil (Wuhan Rongcan Biotechnology Co., Ltd.), 7% vinyl fluorosilicone oil (Guangzhou Kangxi Silicone Materials Co., Ltd., KX-205 ), 8% Gemini fluorocarbon surfactant C ₂ F ₅ N ⁺ (CH ₃ ) ₂ -CH ₂ CH ₂ CH ₂ CH ₂ -(CH ₃ ) ₂ N ⁺ C ₂ F ₅ (homemade: in parts by weight, At 30°C, add 1.5 parts of pentafluorobromoethane to 7 parts of acetone, mix evenly with stirring at 150 rpm, then add 1 part of tetramethylbutanediamine dropwise, add it evenly and completely over 12 minutes, and continue quarterly with stirring at 150 rpm. Ammonization reaction, after 1.5 hours of reaction, filter the precipitate. The obtained precipitate is the prepared Gemini fluorocarbon surfactant), 18% non-ionic fluorocarbon surfactant (3M Company, FC4432), 8% average particle size is 40nm of nanosilica, 6% ethanol and the balance water.

The nanoemulsion is prepared by the following steps: according to the content of each component in the above-mentioned nanoemulsion, water is added to the reaction kettle, and the gemini fluorocarbon surfactant C ₂ F is mixed at 35° C. and a stirring speed of 500 rpm. ₅ N ⁺ (CH ₃ ) ₂ -CH ₂ CH ₂ CH ₂ CH ₂ -(CH ₃ ) ₂ N ⁺ C ₂ F _5. Add nonionic fluorocarbon surfactant to the reaction kettle and stir for 15 minutes; then add propanol, Continue stirring for 20 minutes; then add nano-silica and continue stirring for 20 minutes; add hydroxyl fluorosilicone oil and vinyl fluorosilicone oil dropwise at the speed of uniform dripping for 30 minutes, and continue stirring for 35 minutes; finally, use ultrasonic treatment with a frequency of 30 kilohertz. In 35 minutes, the nanoemulsion was obtained.

The nonionic fluorocarbon surfactant is FC4432 from 3M Company.

The fungicide is dodecyldimethylbenzylammonium bromide.

The viscosity regulator is a complex obtained by the complex reaction of diisopropyl di(triethanolamine) titanate and glycerin. It is prepared through the following steps: according to the weight ratio of diisopropyl di(triethanolamine) titanate: glycerin: water is 25:38:37, add diisopropyl di(triethanolamine) titanate and propylene glycol. Triol and water were mixed and complexed at 70°C for 2 hours to obtain the viscosity modifier.

The clay stabilizer is tetramethylammonium chloride.

The gel breaker is sodium persulfate.

The modifier is 3-aminopropyltriethoxysilane.

The preparation method of the integrated fracturing fluid in this embodiment includes the following steps: under the stirring condition of 180 rpm, slowly add 0.4% of the drag-reducing tackifier to water, stir and mix evenly; then add 0.03% of the The fungicide, 0.4% of the clay stabilizer, 0.15% of the modifier, 0.4% of the nanoemulsion, and 0.08% of the non-ionic fluorocarbon surfactant, stir and mix evenly; then add 0.3% of the viscosity regulator, stir and mix evenly; finally add 0.3% of the gas generating agent and 0.1% of the gel breaker, stir evenly to obtain an integrated fracturing fluid. The integrated fracturing fluid obtained in Example 4 is a high-viscosity jelly fracturing fluid.

The fracturing fluid prepared in Example 4, Example 3, Comparative Example 3-1, and Comparative Example 3-2 is a high-viscosity fracturing fluid. The main performance of the fracturing fluid is in accordance with the industry standard NB/T 14003.3-2017 "Shale Gas Fracturing Fluid Part 3: Continuously Mixed Fracturing Fluid Performance Indicators and Evaluation Methods" was tested, and the bacterial content was tested in accordance with the industry standard NB/T 14003.1-2015 "Shale Gas Fracturing Fluid Part 1: Slippery Water Performance Indicators and Evaluation Methods" 》Detection. The test results of the main properties of fracturing fluid are shown in Table 7. The suspended sand performance test was performed according to the test method of Example 1, and the test results are shown in Table 8.

Table 7 Main properties of fracturing fluids in Example 4, Example 3, Comparative Example 3-1, and Comparative Example 3-2

Table 8 Fracturing fluid sand suspension properties of Example 4, Example 3, Comparative Example 3-1, and Comparative Example 3-2

It can be seen from the above Table 7 and Table 8 that the performance of the fracturing fluid of Example 4 is equivalent to that of Example 3 in all aspects.

To sum up, the fracturing fluid provided by the present invention has lower friction resistance than conventional fracturing fluid, and the friction reduction rate is increased by 2.1-11.2 percentage points, and the higher the viscosity, the greater the improvement in the drag reduction rate. At the same time, the fracturing fluid provided by the present invention has better sand-suspending performance than conventional fracturing fluids of the same viscosity: under low-viscosity conditions, the fracturing fluid provided by the present invention begins to settle after 20 seconds of suspended sand, half of which settles in 3 minutes, and completely settles in 10 minutes. , while the conventional slick water fracturing fluid suspended sand of the same/similar viscosity begins to settle in 0s and completely settles in 10s; under medium viscosity conditions, the fracturing fluid suspended sand provided by the present invention begins to settle after 1 minute, and half of the sedimentation occurs in 5 minutes. There is no obvious continued settlement phenomenon by the 10th minute, while the conventional linear glue fracturing fluid suspension sand of the same/similar viscosity begins to settle in 2s, half settles in 20s, and completely settles in 1min; under high viscosity conditions, the fracturing fluid provided by the present invention The liquid suspended sand did not settle significantly within 10 minutes, while the conventional jelly fracturing fluid suspended sand with the same/similar viscosity settled by 10% in 10 minutes.

Claims

An integrated fracturing fluid, which includes the following components in terms of mass percentage: 0.02%-0.5% drag-reducing tackifier, 0.1%-0.5% nanoemulsion, 0.02%-0.1% first nonionic Fluorocarbon surfactant, 0.003%-0.05% fungicide, 0-0.5% viscosity regulator, 0-0.5% clay stabilizer, 0-0.1% gel breaker, 0.05%-0.2% modification agent, 0.1%-1% gas generating agent, the balance is water;

Preferably, when the integrated fracturing fluid contains a viscosity modifier, the content of the viscosity modifier is 0.1%-0.5% based on the total mass of the integrated fracturing fluid being 100%;

Preferably, when the integrated fracturing fluid contains a gel breaker, the content of the gel breaker is 0.02%-0.1% based on the total mass of the integrated fracturing fluid being 100%;

Preferably, when the integrated fracturing fluid contains a clay stabilizer, the content of the clay stabilizer is 0.01%-0.5% based on the total mass of the integrated fracturing fluid being 100%.
The integrated fracturing fluid according to claim 1, wherein the drag reducing and thickening agent is a mixture of hydrolyzed polyacrylamide and/or its derivatives and non-hydrolyzed polyacrylamide and/or its derivatives; preferably , the mass ratio of the hydrolyzed polyacrylamide and/or its derivatives to the non-hydrolyzed polyacrylamide and/or its derivatives is (10-15):1.
The integrated fracturing fluid according to claim 2, wherein in the drag reducing and thickening agent, the hydrolyzed polyacrylamide and/or its derivatives have a viscosity average molecular weight of 5 million to 15 million, and a degree of hydrolysis It is 20%-30%; the viscosity average molecular weight of the non-hydrolyzable polyacrylamide and/or its derivatives is 5 million-15 million.
The integrated fracturing fluid according to claim 1, wherein the nanoemulsion is a nanoemulsion with an average particle size ≤ 150 nm;

Preferably, based on the total mass of the nanoemulsion being 100%, it includes the following components: 10%-20% fluorine-containing silicone oil, 5%-10% Gemini fluorocarbon surfactant, 15%-25% The second nonionic fluorocarbon surfactant, 5%-10% nanosilica, 1%-10% lower alcohol, and the balance is water;

More preferably, the fluorosilicone oil includes one or a combination of hydroxyl fluorosilicone oil, vinyl fluorosilicone oil, methyl fluorosilicone oil and polyether fluorosilicone oil;

More preferably, the general structural formula of the gemini fluorocarbon surfactant is: C n F 2n+1 N + (CH 3 ) 2 -CH 2 CH 2 CH 2 CH 2 -(CH 3 ) 2 N + C n F 2n+1 , where n is 2-4;

More preferably, the second nonionic fluorocarbon surfactant includes polyoxyethylene ethers containing fluorine-containing fatty alcohols, polyoxyethylene ethers containing fluorine-containing phenols, polyoxyethylene ethers containing fluorine-containing alkylsulfonyl alcoholamines, One or a combination of polyoxyethylene esters of fluorocarboxylic acids and polyoxyethylene ethers of fluorine-containing thiols;

More preferably, the particle size of the nanosilica is 15-50nm;

More preferably, the lower alcohol includes one or a combination of methanol, ethanol, propanol and butanol.
The integrated fracturing fluid according to claim 4, wherein the nanoemulsion is prepared by the following steps: stirring at 10-40°C and 120-600rpm according to the content of each component in the nanoemulsion. At high speed, add gemini fluorocarbon surfactant and non-ionic fluorocarbon surfactant to the water, and then stir for 10-30 minutes; then add lower alcohol and continue stirring for 10-30 minutes; then add nano-silica and continue stirring for 10-30 minutes. ; Add fluorine-containing silicone oil dropwise, and continue stirring for 30-60 minutes; finally, use ultrasonic treatment for 20-40 minutes to obtain the nanoemulsion.
The integrated fracturing fluid according to claim 1, wherein the first nonionic fluorocarbon surfactant includes polyoxyethylene ethers containing fluorine-containing fatty alcohols, polyoxyethylene ethers containing fluorine-containing phenols, and fluorine-containing alkyl groups. One or a combination of polyoxyethylene ethers of sulfonyl alcohol amines, polyoxyethylene esters of fluorine-containing carboxylic acids, and polyoxyethylene ethers of fluorine-containing thiols.
The integrated fracturing fluid according to claim 1, wherein the bactericide includes one or a combination of aldehyde bactericides, quaternary ammonium salt bactericides and isothiazolinone bactericides;

Preferably, the aldehyde bactericide includes one or a combination of glutaraldehyde, formaldehyde and acrolein;

Preferably, the quaternary ammonium salt fungicides include tetradecyldimethylbenzylammonium chloride, dodecyltrimethylammonium chloride, dodecyldimethylbenzylammonium chloride and tetradecyltrimethylammonium chloride. One or a combination of several dialkyldimethylbenzylammonium bromides;

Preferably, the isothiazolinone fungicide includes methylisothiazolinone and/or methylchloroisothiazolinone.
The integrated fracturing fluid according to claim 1, wherein the viscosity modifier includes one or a combination of water-soluble zirconium salts, water-soluble titanium salts, water-soluble chromium salts and water-soluble aluminum salts;

Preferably, the viscosity modifier includes: water-soluble zirconium salt, water-soluble titanium salt, water-soluble chromium salt and water-soluble aluminum salt respectively obtained by complex reaction with polyhydric alcohols. Water-soluble organic zirconium salt and water-soluble organic titanium salt , one or a combination of water-soluble organic chromium salts and water-soluble organic aluminum salts.
The integrated fracturing fluid according to claim 8, wherein the water-soluble organic zirconium salt includes zirconium oxychloride and sorbitol, glycerol, ethylene glycol, 1,2-propylene glycol, 1,4-butane A complex obtained by the complex reaction of one or more of diol, diethylene glycol and triethylene glycol.
The integrated fracturing fluid according to claim 8, wherein the water-soluble organic titanium salt includes di(triethanolamine) diisopropyl titanate, tetraisopropyl orthotitanate, dilactide orthotitanate. One or a combination of isopropyl ester and diacetylacetonate diisopropyl orthotitanate; or di(triethanolamine) diisopropyl titanate, tetraisopropyl orthotitanate, orthotitanium One or a combination of diisopropyl acid bislactate and diacetylacetonate diisopropyl orthotitanate and sorbitol, glycerol, ethylene glycol, 1,2-propanediol, 1,4 -A complex obtained by a combined complexation reaction of one or more of butanediol, diethylene glycol and triethylene glycol.
The integrated fracturing fluid according to claim 8, wherein the water-soluble organic chromium salt includes one or a combination of one or more of chromium lactate, chromium acetate, chromium chloride and chromium sulfate, and sorbitol and propane. Alcohol, ethylene glycol, 1,2-propane The complex is obtained by the combined complexation reaction of one or more of diol, 1,4-butanediol, diethylene glycol and triethylene glycol.
The integrated fracturing fluid according to claim 8, wherein the water-soluble organic aluminum salt includes one or more of potassium aluminum sulfate dodecahydrate, aluminum sulfate, aluminum lactate, aluminum acetate and aluminum chloride. obtained by complex reaction with one or more combinations of sorbitol, glycerol, ethylene glycol, 1,2-propanediol, 1,4-butanediol, diethylene glycol and triethylene glycol. complex.
The integrated fracturing fluid according to claim 1, wherein the clay stabilizer includes one or a combination of tetramethylammonium chloride, potassium chloride and polyquaternium salts.
The integrated fracturing fluid according to claim 1, wherein the gel breaker includes one or a combination of ammonium persulfate, sodium persulfate and potassium persulfate.
The integrated fracturing fluid according to claim 1, wherein the modifier includes a silane modifier;

Preferably, the silane modifier includes N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane and N-β-aminoethyl- One or a combination of several of γ-aminopropyltrimethoxysilane.
The integrated fracturing fluid according to claim 1, wherein the gas generating agent includes effervescent tablet particles;

Preferably, the effervescent tablet particles are those in which the acid source is citric acid, the alkali source is sodium bicarbonate, and polyethylene glycol is a capsule coating.
A method for preparing integrated fracturing fluid according to any one of claims 1-16, which includes the following steps:

When preparing indoors:

S1. Under stirring conditions of 60-200 rpm, based on the total mass of the integrated fracturing fluid being 100%, add 0.02%-0.5% drag reducing and thickening agent into the water, stir and mix evenly;

S2. Then add 0.003%-0.05% fungicide, 0-0.5% clay stabilizer, 0.05%-0.2% modifier, 0.1%-0.5% nanoemulsion, 0.02%-0.1% first non- ionic fluorocarbon surfactant, stir and mix evenly to obtain the first mixed liquid;

S3. According to the viscosity requirements of the required fracturing fluid, add 0-0.5% viscosity modifier to the first mixed liquid, stir and mix evenly, and obtain the second mixed liquid;

S4. Add 0.1%-1% gas generating agent and 0-0.1% gel breaker to the second mixed liquid, stir evenly, and obtain the integrated fracturing fluid;

When prepared on site:

The preparation steps of S1-S3 are the same as those in indoor preparation. The preparation steps of S4 are: add 0.1%-1% gas generating agent and 0-0.1% gel breaker into the sand mixing tank of the sand mixing truck, and mix with the above The second mixed liquid and sand are mixed together in the sand mixing truck Mix well in the jar.