Emulsion drag reducer as well as preparation method and application thereof
By preparing an emulsion drag reducer, the problem in the prior art that drag reducers cannot simultaneously reduce drag and assist drainage is solved, thereby achieving efficient drag reduction and drainage assistance effects in oil fracturing construction and reducing construction costs.
Patent Information
- Application Number
- CN202510877472.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-27
- Publication Date
- 2025-09-23
AI Technical Summary
Existing drag reducers cannot simultaneously meet the requirements of drag reduction, drainage assistance, and low cost, resulting in the inability to efficiently carry proppants in long horizontal well sections and complex fractures, increasing construction costs and complexity.
The emulsion drag reducer is composed of polymer, water-soluble polyquaternary ammonium salt, water-soluble surfactant, white oil, water, emulsifier and cosolvent. It forms a uniform and stable emulsion through polymerization reaction, and has good drag reduction, drainage and anti-swelling effects.
It has achieved the functions of drag reduction and drainage assistance in oil fracturing construction, reduced construction costs, improved fracturing efficiency, and met the process requirements of on-site preparation and injection.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of petroleum fracturing emulsion drag reducers, and in particular to an emulsion drag reducer and a preparation method and application thereof. Background Art
[0002] In recent years, the proportion of unconventional oil and gas reservoirs in proven oil and gas reserves has increased significantly, making the exploration and development of unconventional oil and gas resources particularly important. Due to the low permeability of unconventional oil and gas reservoirs, industrial production often requires hydraulic fracturing. Slickwater, one of the most widely used fracturing fluids, reduces frictional resistance in high-speed pumping pipelines and minimizes reservoir damage. Drag reducers, the core additives in slickwater, are typically high-molecular-weight polyacrylamide or copolymers of acrylamide and other monomers. Drag reducers improve fracturing efficiency by preventing the transition from laminar to turbulent flow in the pipeline or by reducing turbulence. In addition to drag reducers, other treatment agents such as clay stabilizers, drainage aids, and biocides are also required in slickwater. Conventional slickwater has excellent drag reduction, but its sand-carrying capacity is limited. In long horizontal well sections and complex fractures, it cannot carry proppant to the fracture end, significantly compromising fracturing effectiveness. Current construction operations address this issue by combining the use of slickwater fracturing fluid to create complex seams with the use of glue to carry sand. However, as slickwater and glue are two different fracturing fluid systems, using the same pumping pipe during construction can lead to pipe blockage or fluid failure due to incompatibility between the two fracturing fluid systems. Furthermore, installing separate pipelines for pumping would increase the area of the well site and incur additional costs.
[0003] Therefore, there is an urgent need to invent a multifunctional drag reducer that combines drag reduction / drainage aid / clay with stable functions. Through a set of systems, it can achieve low-viscosity and high-efficiency drag reduction to create complex fractures while carrying proppants to the end of the fractures with high viscosity, realize online automatic preparation of slick water, meet the on-site preparation and injection process requirements, and achieve the purpose of improving the efficiency of fracturing construction. Summary of the Invention
[0004] The purpose of the present invention is to overcome the problem that the drag reducers in the prior art cannot simultaneously meet the functions of drag reduction, drainage assistance and low cost, and to provide an emulsion drag reducer that can simultaneously meet the functions of drag reduction and drainage assistance with good effects. The preparation method of the present invention is low in cost, simple in process and efficient.
[0005] In order to achieve the above object, the present invention provides an emulsion drag reducer on one hand, wherein the emulsion drag reducer comprises a polymer, a water-soluble polyquaternary ammonium salt, a water-soluble surfactant, white oil, water, an emulsifier and a cosolvent; wherein the content of the polymer is 15-32 wt%; The polymer includes: The first structural unit is provided by a terminal olefin sulfonate monomer; The second structural unit is provided by acrylamide monomers; The weight ratio of the first structural unit to the second structural unit is 1:2-6; The weight average molecular weight of the polymer is 2 million to 10 million.
[0006] Preferably, the weight ratio of the first structural unit to the second structural unit is 1:3-5.
[0007] Preferably, the terminal olefin sulfonate monomer is selected from one or more of sodium 2-acrylamide-2-methylpropane sulfonate, sodium methyl propene sulfonate, potassium 2-acrylamide-2-methylpropane sulfonate and potassium methyl propene sulfonate.
[0008] Preferably, the acrylamide monomer is selected from one or more of acrylamide, methacrylamide, N,N-dimethylacrylamide and N-isopropylacrylamide.
[0009] Preferably, the content of the water-soluble polyquaternium salt is 2-8 wt %.
[0010] Preferably, the content of the water-soluble surfactant is 1.5-6.5 wt %.
[0011] Preferably, the content of the white oil is 25-50 wt%.
[0012] Preferably, the water content is 18-40 wt%.
[0013] Preferably, the content of the emulsifier is 3-8 wt %.
[0014] Preferably, the content of the co-solvent is 0.2-0.8 wt %.
[0015] Preferably, the water-soluble polyquaternary ammonium salt is selected from one or more of dimethyldiallylammonium chloride homopolymer, allyltrimethylammonium chloride homopolymer, acrylamidopropyltrimethylammonium chloride homopolymer and methacryloyloxyethyltrimethylammonium chloride homopolymer.
[0016] Preferably, the water-soluble surfactant is selected from one or more of sodium pentafluorooctanoate, potassium pentafluorooctanoate and perfluorooctyl polyoxyethylene ether.
[0017] Preferably, the emulsifier is sorbitan oleate and / or polyoxyethylene sorbitan monostearate.
[0018] Preferably, the co-solvent is selected from one or more of urea, methanol and ethanol.
[0019] The second aspect of the present invention provides a method for preparing the above-mentioned emulsion drag reducer, which comprises the following steps: (1) Preparing an emulsified solution containing white oil and an emulsifier; (2) preparing an aqueous phase liquid containing water, a terminal olefin sulfonate monomer, an acrylamide monomer, a water-soluble polyquaternary ammonium salt, a water-soluble surfactant, a cosolvent and an inhibitor; (3) adding the aqueous phase liquid to the emulsified solution to obtain a mixed emulsion; (4) subjecting the mixed emulsion to a polymerization reaction in the presence of an inert atmosphere and an initiator; Wherein, the total weight of white oil, emulsifier, water, terminal olefin sulfonate monomer, acrylamide monomer, water-soluble polyquaternary ammonium salt, water-soluble surfactant and cosolvent is 100%, and the content of the terminal olefin sulfonate monomer and the acrylamide monomer is 15-32wt%.
[0020] Preferably, the ratio of the total amount of the terminal olefin sulfonate monomer and the acrylamide monomer to the amount of the polymerization inhibitor is 100:1-2.5.
[0021] Preferably, the polymerization inhibitor is sodium formate and / or potassium formate.
[0022] Preferably, the initiator is ammonium persulfate and / or tetramethylethylenediamine.
[0023] Preferably, the initiator is ammonium persulfate and tetramethylethylenediamine.
[0024] Preferably, the weight ratio of the ammonium persulfate to the tetramethylethylenediamine is 1:0.5-1.5.
[0025] Preferably, the polymerization reaction conditions include: temperature of 35-50° C. and time of 4-8 h.
[0026] A third aspect of the present invention provides the use of the emulsion drag reducer in petroleum fracturing construction.
[0027] The emulsion drag reducer of the present invention is in a uniform and stable emulsion state. Due to the mutual cooperation between the various components, the emulsion drag reducer of the present invention has good drag reduction, drainage and anti-swelling effects, and has a good application prospect in oil fracturing construction. In addition, the process of preparing the emulsion drag reducer by the method described in the present invention is simple and efficient. DETAILED DESCRIPTION
[0028] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.
[0029] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.
[0030] In one aspect, the present invention provides an emulsion drag reducer, which comprises a polymer, a water-soluble polyquaternary ammonium salt, a water-soluble surfactant, white oil, water, an emulsifier, and a cosolvent; wherein the content of the polymer is 15-32 wt%; The polymer includes: The first structural unit is provided by a terminal olefin sulfonate monomer; The second structural unit is provided by acrylamide monomers; The weight ratio of the first structural unit to the second structural unit is 1:2-6; The weight average molecular weight of the polymer is 2 million to 10 million.
[0031] The emulsion drag reducer of the present invention is based on the formation of a uniform and stable emulsion between the polymer, water-soluble polyquaternary ammonium salt, water-soluble surfactant, white oil, water, emulsifier and cosolvent, thereby simultaneously achieving good drag reduction, drainage and anti-swelling functions, and the effect is good.
[0032] In the present invention, the polymer is obtained by polymerizing a terminal olefin sulfonate monomer and an acrylamide monomer, so that the emulsion drag reducer has a good drag reduction effect.
[0033] In the present invention, the weight average molecular weight of the polymer is obtained by gel permeation chromatography, and the weight average molecular weight of the polymer is 2 million to 10 million, preferably 5 million to 8 million.
[0034] In the present invention, the content of the polymer in the emulsion drag reducer is 15-32 wt %, preferably 20-30 wt %. Based on the above content of the polymer in the emulsion drag reducer, the emulsion drag reducer has a good drag reduction effect.
[0035] In a preferred embodiment, in order to further improve the drag reduction effect of the emulsion drag reducer, the weight ratio of the first structural unit to the second structural unit is 1:3-5.
[0036] In the present invention, in order to further improve the drag reduction effect of the emulsion drag reducer, in a preferred embodiment, the terminal olefin sulfonate monomer is selected from one or more of sodium 2-acrylamide-2-methylpropane sulfonate, sodium methyl propene sulfonate, potassium 2-acrylamide-2-methylpropane sulfonate and potassium methyl propene sulfonate.
[0037] In the present invention, in order to further improve the drag reduction effect of the emulsion drag reducer, in a preferred embodiment, the acrylamide monomer is selected from one or more of acrylamide, methacrylamide, N,N-dimethylacrylamide and N-isopropylacrylamide.
[0038] In a preferred embodiment, in order to further improve the anti-swelling effect of the emulsion drag reducer, the content of the water-soluble polyquaternary ammonium salt is 2-8 wt %; preferably 2.5-6 wt %.
[0039] In a preferred embodiment, in order to further improve the drainage effect of the emulsion drag reducer, the content of the water-soluble surfactant is 1.5-6.5 wt %; preferably 2-5 wt %.
[0040] In a preferred embodiment, in order to improve the uniform stability of the emulsion drag reducer, the content of the white oil is 25-50 wt %, preferably 30-45 wt %.
[0041] In a preferred embodiment, in order to improve the uniform stability of the emulsion drag reducer, the water content is 18-40 wt %, preferably 25-35 wt %.
[0042] In a preferred embodiment, in order to further improve the uniform stability of the emulsion drag reducer, the content of the emulsifier is 3-8 wt %, preferably 3.5-6 wt %.
[0043] In a preferred embodiment, in order to further improve the uniform stability of the emulsion drag reducer, the content of the co-solvent is 0.2-0.8 wt %, preferably 0.25-0.6 wt %.
[0044] In a preferred embodiment, the water-soluble polyquaternary ammonium salt is selected from one or more of dimethyldiallyl ammonium chloride homopolymer, allyltrimethylammonium chloride homopolymer, acrylamidopropyltrimethylammonium chloride homopolymer and methacryloyloxyethyltrimethylammonium chloride homopolymer; based on the selection of the above water-soluble quaternary ammonium salt, the emulsion drag reducer has a better anti-swelling effect.
[0045] In a preferred embodiment, the water-soluble surfactant is selected from one or more of sodium pentadecafluorooctanoate, potassium pentadecafluorooctanoate and perfluorooctyl polyoxyethylene ether; based on the selection of the above water-soluble surfactants, the emulsion drag reducer has a better drainage effect.
[0046] In a preferred embodiment, the emulsifier is sorbitan oleate (Span80) and / or polysorbate 80 (tween80); more preferably, the emulsifier is sorbitan oleate and polyoxyethylene sorbitan monostearate; further preferably, the weight ratio of the emulsifier sorbitan oleate to the polyoxyethylene sorbitan monostearate is 4-6:1.
[0047] In a preferred embodiment, the co-solvent is selected from one or more of urea, methanol and ethanol.
[0048] The second aspect of the present invention provides a method for preparing the above-mentioned emulsion drag reducer, which comprises the following steps: (1) Preparing an emulsified solution containing white oil and an emulsifier; (2) preparing an aqueous phase liquid containing water, a terminal olefin sulfonate monomer, an acrylamide monomer, a water-soluble polyquaternary ammonium salt, a water-soluble surfactant, a cosolvent and an inhibitor; (3) adding the aqueous phase liquid to the emulsified solution to obtain a mixed emulsion; (4) subjecting the mixed emulsion to a polymerization reaction in the presence of an inert atmosphere and an initiator; Wherein, the total weight of white oil, emulsifier, water, terminal olefin sulfonate monomer, acrylamide monomer, water-soluble polyquaternary ammonium salt, water-soluble surfactant and cosolvent is 100%, and the content of the terminal olefin sulfonate monomer and the acrylamide monomer is 15-32wt%.
[0049] The above-mentioned emulsion drag reducer can be prepared by the method of the present invention, wherein the addition of the initiator and the polymerization inhibitor can control the terminal olefin sulfonate monomer and the acrylamide monomer to form the polymer described above and control the weight average molecular weight of the polymer to be 2 million to 10 million. Preferably, the weight average molecular weight of the polymer is 5 million to 8 million.
[0050] In a preferred embodiment, the ratio of the total amount of the terminal olefin sulfonate monomer and the acrylamide monomer to the amount of the polymerization inhibitor is 100:1-2.5.
[0051] In a preferred embodiment, the polymerization inhibitor is sodium formate and / or potassium formate.
[0052] In the present invention, there is no special requirement for the initiator, and any initiator commonly used in the art for initiating polymerization reactions can be used; in a preferred embodiment, the initiator is ammonium persulfate and / or tetramethylethylenediamine; more preferably, the initiator is ammonium persulfate and tetramethylethylenediamine.
[0053] In a more preferred embodiment, the weight ratio of the ammonium persulfate to the tetramethylethylenediamine is 1:0.5-1.5.
[0054] In a preferred embodiment, the polymerization reaction conditions include: temperature of 35-50° C. and time of 4-8 hours.
[0055] A third aspect of the present invention provides the use of the emulsion drag reducer in petroleum fracturing construction.
[0056] The emulsion drag reducer of the present invention has good drag reduction, drainage assistance and anti-swelling effects, and has good application prospects in oil fracturing construction.
[0057] The following examples further illustrate the emulsion drag reducer, its preparation method, and application of the present invention. The examples are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the scope of protection of the present invention is not limited to the following examples.
[0058] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.
[0059] Example 1 (1) Weigh 60 g of white oil, add 8 g of Span 80 and 2 g of Tween 80 emulsifiers thereto, and stir and mix at a speed of 10,000 r / min for 10 min to obtain an emulsified solution; (2) Weigh 38 g of water, add terminal olefin sulfonate monomers (2 g of sodium 2-acrylamide-2-methylpropanesulfonate, 2 g of sodium methylpropenesulfonate and 2 g of potassium 2-acrylamide-2-methylpropanesulfonate), acrylamide monomers (14 g of acrylamide and 14 g of methylacrylamide), water-soluble polyquaternary ammonium salt (4 g of polydimethyldiallylammonium chloride), water-soluble surfactant (4 g of sodium pentafluorooctanoate), cosolvent (0.4 g of urea) and polymerization inhibitor (0.4 g of sodium formate) in sequence, and stir to obtain an aqueous phase liquid; (3) adding the aqueous phase liquid to the emulsified solution and stirring at a rate of 10,000 r / min for 20 min to obtain a mixed emulsion; (4) Nitrogen was introduced into the mixed emulsion, and 2 mL of initiator solution (containing 0.01 g of ammonium persulfate, 0.01 g of tetramethylethylenediamine and 2 g of water) was added at a rate of 500 r / min. The mixed emulsion was polymerized at a temperature of 30°C for 5 h to obtain a uniform and stable emulsion drag reducer F1.
[0060] Example 2 (1) Weigh 80 g of white oil, add 10 g of Span 80 and 2 g of Tween 80 emulsifiers thereto, and stir and mix at a speed of 10,000 r / min for 10 min to obtain an emulsified solution; (2) Weigh 54 g of water, add terminal olefin sulfonate monomer (6 g of sodium 2-acrylamide-2-methylpropanesulfonate), acrylamide monomer (12 g of methacrylamide, 12 g of N,N-dimethylacrylamide, 12 g of N-isopropylacrylamide), water-soluble polyquaternary ammonium salt (6 g of polydimethyldiallyl ammonium chloride), water-soluble surfactant (3 g of potassium pentadecafluorooctanoate and 3 g of perfluorooctyl polyoxyethylene ether), cosolvent (0.6 g of methanol) and polymerization inhibitor (0.6 g of sodium formate) in sequence, and stir to obtain an aqueous phase liquid; (3) adding the aqueous phase liquid to the emulsified solution and stirring at a rate of 10,000 r / min for 20 min to obtain a mixed emulsion; (4) Nitrogen was introduced into the mixed emulsion, and 6 mL of initiator solution (containing 0.03 g of ammonium persulfate, 0.03 g of tetramethylethylenediamine and 6 g of water) was added at a rate of 400 r / min. The mixed emulsion was polymerized at a temperature of 40°C for 6 h to obtain a uniform and stable emulsion drag reducer F2.
[0061] Example 3 (1) Weigh 70 g of white oil, add 8 g of Span 80 and 2 g of Tween 80 emulsifiers thereto, and stir and mix at a speed of 10,000 r / min for 10 min to obtain an emulsified solution; (2) Weigh 46 g of water, add terminal olefin sulfonate monomer (10 g of potassium methyl propylene sulfonate), acrylamide monomer (32 g of N-isopropyl acrylamide), water-soluble polyquaternary ammonium salt (4 g of polyacrylamidopropyl trimethyl ammonium chloride and 4 g of polymethacryloyloxyethyl trimethyl ammonium chloride), water-soluble surfactant (8 g of perfluorooctyl polyoxyethylene ether), cosolvent (0.6 g of urea) and polymerization inhibitor (0.6 g of sodium formate) in sequence, and stir to obtain an aqueous phase liquid; (3) adding the aqueous phase liquid to the emulsified solution and stirring at a rate of 10,000 r / min for 20 min to obtain a mixed emulsion; (4) Nitrogen was introduced into the mixed emulsion, and 4 mL of initiator solution (containing 0.02 g of ammonium persulfate, 0.02 g of tetramethylethylenediamine and 4 g of water) was added at a rate of 300 r / min. The mixed emulsion was polymerized at a temperature of 40°C for 5 h to obtain a uniform and stable emulsion drag reducer F3.
[0062] Example 4 (1) Weigh 80 g of white oil, add 10 g of Span 80 and 2 g of Tween 80 emulsifiers thereto, and stir and mix at a speed of 10,000 r / min for 10 min to obtain an emulsified solution; (2) Weigh 54 g of water, add terminal olefin sulfonate monomer (14 g of sodium 2-acrylamide-2-methylpropanesulfonate), acrylamide monomer (9 g of methacrylamide, 9 g of N,N-dimethylacrylamide, 10 g of N-isopropylacrylamide), water-soluble polyquaternary ammonium salt (6 g of polydimethyldiallyl ammonium chloride), water-soluble surfactant (3 g of potassium pentadecafluorooctanoate and 3 g of perfluorooctyl polyoxyethylene ether), cosolvent (0.6 g of methanol) and polymerization inhibitor (0.6 g of sodium formate) in sequence, and stir to obtain an aqueous phase liquid; (3) adding the aqueous phase liquid to the emulsified solution and stirring at a rate of 10,000 r / min for 20 min to obtain a mixed emulsion; (4) Nitrogen was introduced into the mixed emulsion, and 6 mL of initiator solution (containing 0.03 g of ammonium persulfate, 0.03 g of tetramethylethylenediamine and 6 g of water) was added at a rate of 400 r / min. The mixed emulsion was polymerized at a temperature of 40°C for 6 h to obtain a uniform and stable emulsion drag reducer F4.
[0063] Comparative Example 1 (1) Weigh 60 g of white oil, add 8 g of Span 80 and 2 g of Tween 80 emulsifiers thereto, and stir and mix at a speed of 10,000 r / min for 10 min to obtain an emulsified solution; (2) Weigh 38 g of water, add terminal olefin sulfonate monomers (1 g of sodium 2-acrylamide-2-methylpropanesulfonate, 1 g of sodium methylpropenesulfonate and 1 g of potassium 2-acrylamide-2-methylpropanesulfonate), acrylamide monomers (7 g of acrylamide and 7 g of methylacrylamide), water-soluble polyquaternary ammonium salt (4 g of polymethacryloyloxyethyl trimethylammonium chloride), water-soluble surfactant (4 g of sodium pentafluorooctanoate), cosolvent (0.4 g of urea) and polymerization inhibitor (0.4 g of sodium formate) in sequence, and stir to obtain an aqueous phase liquid; (3) adding the aqueous phase liquid to the emulsified solution and stirring at a rate of 10,000 r / min for 20 min to obtain a mixed emulsion; (4) Nitrogen was introduced into the mixed emulsion, and 2 mL of initiator solution (containing 0.01 g of ammonium persulfate, 0.01 g of tetramethylethylenediamine and 2 g of water) was added at a rate of 500 r / min. The mixed emulsion was polymerized at a temperature of 30°C for 5 h to obtain a uniform and stable emulsion drag reducer D1.
[0064] Comparative Example 2 (1) Weigh 60 g of white oil, add 8 g of Span 80 and 2 g of Tween 80 emulsifiers thereto, and stir and mix at a speed of 10,000 r / min for 10 min to obtain an emulsified solution; (2) Weigh 38 g of water, add terminal olefin sulfonate monomers (2 g of sodium 2-acrylamide-2-methylpropanesulfonate, 2 g of sodium methylpropenesulfonate and 2 g of potassium 2-acrylamide-2-methylpropanesulfonate), acrylamide monomers (14 g of acrylamide and 14 g of methacrylamide), a water-soluble surfactant (4 g of sodium pentadecafluorooctanoate), a cosolvent (0.4 g of urea) and a polymerization inhibitor (0.4 g of sodium formate) in sequence, and stir to obtain an aqueous phase liquid; (3) adding the aqueous phase liquid to the emulsified solution and stirring at a rate of 10,000 r / min for 20 min to obtain a mixed emulsion; (4) Nitrogen was introduced into the mixed emulsion, and 2 mL of initiator solution (containing 0.01 g of ammonium persulfate, 0.01 g of tetramethylethylenediamine and 2 g of water) was added at a rate of 500 r / min. The mixed emulsion was polymerized at a temperature of 30°C for 5 h to obtain a uniform and stable emulsion drag reducer D2.
[0065] Comparative Example 3 (1) Weigh 60 g of white oil, add 8 g of Span 80 and 2 g of Tween 80 emulsifiers thereto, and stir and mix at a speed of 10,000 r / min for 10 min to obtain an emulsified solution; (2) Weigh 38 g of water, add terminal olefin sulfonate monomer (2 g of sodium 2-acrylamide-2-methylpropanesulfonate, 2 g of sodium methylpropenesulfonate and 2 g of potassium 2-acrylamide-2-methylpropanesulfonate), acrylamide monomer (14 g of acrylamide and 14 g of methacrylamide), water-soluble polyquaternium salt (4 g of polydimethyldiallylammonium chloride), cosolvent (0.4 g of urea) and polymerization inhibitor (0.4 g of sodium formate) in sequence, and stir to obtain an aqueous phase liquid; (3) adding the aqueous phase liquid to the emulsified solution and stirring at a rate of 10,000 r / min for 20 min to obtain a mixed emulsion; (4) Nitrogen was introduced into the mixed emulsion, and 2 mL of initiator solution (containing 0.01 g of ammonium persulfate, 0.01 g of tetramethylethylenediamine and 2 g of water) was added at a rate of 500 r / min. The mixed emulsion was polymerized at a temperature of 30°C for 5 h to obtain a uniform and stable emulsion drag reducer D3.
[0066] Comparative Example 4 (1) Weigh 60 g of white oil, add 8 g of Span 80 and 2 g of Tween 80 emulsifiers thereto, and stir and mix at a speed of 10,000 r / min for 10 min to obtain an emulsified solution; (2) Weigh 38 g of water, add acrylamide monomers (14 g of acrylamide and 14 g of methacrylamide), water-soluble polyquaternary ammonium salt (4 g of polydimethyldiallyl ammonium chloride), water-soluble surfactant (4 g of sodium pentafluorooctanoate), cosolvent (0.4 g of urea) and polymerization inhibitor (0.4 g of sodium formate) in sequence, and stir to obtain an aqueous phase liquid; (3) adding the aqueous phase liquid to the emulsified solution and stirring at a rate of 10,000 r / min for 20 min to obtain a mixed emulsion; (4) Nitrogen was introduced into the mixed emulsion, and 2 mL of initiator solution (containing 0.01 g of ammonium persulfate, 0.01 g of tetramethylethylenediamine and 2 g of water) was added at a rate of 500 r / min. The mixed emulsion was polymerized at a temperature of 30°C for 5 h to obtain a uniform and stable emulsion drag reducer D4.
[0067] Comparative Example 5 (1) Weigh 60 g of white oil, add 8 g of Span 80 and 2 g of Tween 80 emulsifiers thereto, and stir and mix at a speed of 10,000 r / min for 10 min to obtain an emulsified solution; (2) Weigh 38 g of water, add terminal olefin sulfonate monomers (2 g of sodium 2-acrylamide-2-methylpropanesulfonate, 2 g of sodium methylpropenesulfonate and 2 g of potassium 2-acrylamide-2-methylpropanesulfonate), water-soluble polyquaternium salt (4 g of polydimethyldiallylammonium chloride), water-soluble surfactant (4 g of sodium pentafluorooctanoate), cosolvent (0.4 g of urea) and polymerization inhibitor (0.4 g of sodium formate) in sequence, and stir to obtain an aqueous phase liquid; (3) adding the aqueous phase liquid to the emulsified solution and stirring at a rate of 10,000 r / min for 20 min to obtain a mixed emulsion; (4) Nitrogen was introduced into the mixed emulsion, and 2 mL of initiator solution (containing 0.01 g of ammonium persulfate, 0.01 g of tetramethylethylenediamine and 2 g of water) was added at a rate of 500 r / min. The mixed emulsion was polymerized at a temperature of 30°C for 5 h to obtain a uniform and stable emulsion drag reducer D5.
[0068] Comparative Example 6 (1) Weigh 70 g of white oil, add 8 g of Span 80 and 2 g of Tween 80 emulsifiers thereto, and stir and mix at a speed of 10,000 r / min for 10 min to obtain an emulsified solution; (2) Weigh 46 g of water, add terminal olefin sulfonate monomer (21 g of potassium methyl propylene sulfonate), acrylamide monomer (21 g of N-isopropyl acrylamide), water-soluble polyquaternary ammonium salt (4 g of polyacrylamidopropyl trimethyl ammonium chloride and 4 g of polymethacryloyloxyethyl trimethyl ammonium chloride), water-soluble surfactant (8 g of perfluorooctyl polyoxyethylene ether), cosolvent (0.6 g of urea) and polymerization inhibitor (0.6 g of sodium formate) in sequence, and stir to obtain an aqueous phase liquid; (3) adding the aqueous phase liquid to the emulsified solution and stirring at a rate of 10,000 r / min for 20 min to obtain a mixed emulsion; (4) Nitrogen was introduced into the mixed emulsion, and 4 mL of initiator solution (containing 0.02 g of ammonium persulfate, 0.02 g of tetramethylethylenediamine and 4 g of water) was added at a rate of 300 r / min. The mixed emulsion was polymerized at a temperature of 40°C for 5 h to obtain a uniform and stable emulsion drag reducer D6.
[0069] Test Case The products prepared in the examples and comparative examples were subjected to performance tests. The drag reduction rate, surface tension, and anti-swelling rate of 0.1 wt% samples were tested in accordance with the Chinese energy industry standard "NB / T14003.1-2015 Shale Gas Fracturing Fluid Part 1: Slick Water Performance Indicators and Evaluation Methods." The test results are shown in Table 1. Table 1
[0070] The results in Table 1 show that the emulsion drag reducer of the present invention has good performance in terms of drag reduction rate, surface tension, and anti-swelling rate. Its application in oil fracturing construction has good drag reduction, drainage assistance, and anti-swelling effects, and can meet the process requirements of immediate preparation and injection at the construction site, thereby improving construction efficiency and reducing construction costs.
[0071] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.
Claims
1. An emulsion drag reducer, characterized in that: The emulsion drag reducer comprises a polymer, a water-soluble polyquaternary ammonium salt, a water-soluble surfactant, white oil, water, an emulsifier and a cosolvent; wherein the content of the polymer is 15-32 wt%; The polymer includes: The first structural unit is provided by a terminal olefin sulfonate monomer; The second structural unit is provided by acrylamide monomers; The weight ratio of the first structural unit to the second structural unit is 1:2-6; The weight average molecular weight of the polymer is 2 million to 10 million.
2. The emulsion drag reducer according to claim 1, characterized in that The weight ratio of the first structural unit to the second structural unit is 1:3-5.
3. The emulsion drag reducer according to claim 1 or 2, characterized in that: The terminal olefin sulfonate monomer is selected from one or more of sodium 2-acrylamide-2-methylpropane sulfonate, sodium methacrylate sulfonate, potassium 2-acrylamide-2-methylpropane sulfonate and potassium methacrylate sulfonate; and / or The acrylamide monomer is selected from one or more of acrylamide, methacrylamide, N,N-dimethylacrylamide and N-isopropylacrylamide.
4. The emulsion drag reducer according to claim 3, characterized in that The content of the water-soluble polyquaternium salt is 2-8wt%; and / or The content of the water-soluble surfactant is 1.5-6.5wt%; and / or The content of the white oil is 25-50wt%; and / or The water content is 18-40wt%; and / or The content of the emulsifier is 3-8wt%; and / or The content of the co-solvent is 0.2-0.8 wt %.
5. The emulsion drag reducer according to claim 1 or 4, characterized in that: The water-soluble polyquaternary ammonium salt is selected from one or more of dimethyldiallyl ammonium chloride homopolymer, allyltrimethylammonium chloride homopolymer, acrylamidopropyltrimethylammonium chloride homopolymer and methacryloyloxyethyltrimethylammonium chloride homopolymer; and / or The water-soluble surfactant is one or more selected from the group consisting of sodium pentafluorooctanoate, potassium pentafluorooctanoate and perfluorooctyl polyoxyethylene ether; and / or The emulsifier is sorbitan oleate and / or polyoxyethylene sorbitan monostearate; and / or The co-solvent is selected from one or more of urea, methanol and ethanol.
6. The method for preparing the emulsion drag reducer according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: (1) Preparing an emulsified solution containing white oil and an emulsifier; (2) preparing an aqueous phase liquid containing water, a terminal olefin sulfonate monomer, an acrylamide monomer, a water-soluble polyquaternary ammonium salt, a water-soluble surfactant, a cosolvent and an inhibitor; (3) adding the aqueous phase liquid to the emulsified solution to obtain a mixed emulsion; (4) subjecting the mixed emulsion to a polymerization reaction in the presence of an inert atmosphere and an initiator; Wherein, the total weight of white oil, emulsifier, water, terminal olefin sulfonate monomer, acrylamide monomer, water-soluble polyquaternary ammonium salt, water-soluble surfactant and cosolvent is 100%, and the content of the terminal olefin sulfonate monomer and the acrylamide monomer is 15-32wt%.
7. The preparation method according to claim 6, characterized in that The ratio of the total amount of the terminal olefin sulfonate monomer and the acrylamide monomer to the amount of the polymerization inhibitor is 100:1-2.5; Preferably, the polymerization inhibitor is sodium formate and / or potassium formate.
8. The preparation method according to claim 6 or 7, characterized in that The initiator is ammonium persulfate and / or tetramethylethylenediamine; Preferably, the initiator is ammonium persulfate and tetramethylethylenediamine; Preferably, the weight ratio of the ammonium persulfate to the tetramethylethylenediamine is 1:0.5-1.
5.
9. The preparation method according to claim 8, characterized in that The polymerization reaction conditions include: temperature of 35-50° C. and time of 4-8 hours.
10. Use of the emulsion drag reducer according to any one of claims 1 to 5 in petroleum fracturing construction.