Multifunctional blending-free full-suspension resistance reducing agent as well as preparation method and application thereof

Abstract

The invention discloses a multifunctional blending-free full-suspension resistance reducing agent as well as a preparation method and application thereof, and belongs to the technical field of fracturing fluids. The multifunctional blending-free full-suspension resistance reducing agent comprises the following raw materials in parts by weight: 30-50 parts of partially hydrolyzed polyacrylamide, 35-60 parts of white oil, 2-5 parts of an anionic surfactant, 0-3 parts of a bactericide, 0.5-2 parts of organic clay, 0.5-1.5 parts of an alcohol compound and 1-3 parts of an emulsifier. The invention further discloses a preparation method and application of the multifunctional blending-free full-suspension resistance reducing agent. The multifunctional blending-free full-suspension resistance reducing agent is a multifunctional suspension type resistance reducing agent, can achieve the integrated functions of salt resistance reduction, sand carrying, swelling prevention, discharge aiding and sterilization without additional auxiliary agents, and has good application value.

Description

Technical Field

[0001] The invention belongs to the technical field of fracturing fluids, and in particular relates to a multifunctional mixing-free fully suspended drag reducing agent and a preparation method and application thereof. Background Art

[0002] The country's demand for energy is increasing. At present, the incremental reserves proved in China are mainly concentrated in unconventional oil and gas reservoirs. Most of the target layers of these oil and gas reservoirs are low-permeability and deep oil and gas. For the vast majority of low-permeability unconventional oil and gas reservoirs, there is no economic exploitation value at all if they are not put into production using large-scale reservoir transformation technology. Therefore, large-scale reservoir transformation technology is an important measure to achieve the effective development of low-permeability oil and gas resources. At present, the transformation technology of unconventional oil and gas reservoirs is mainly volume fracturing, and its construction liquid is mainly variable viscosity fracturing fluid. The low concentration is efficient drag-reducing slick water. Slick water fracturing has the characteristics of large displacement, large liquid volume, large sand volume, low sand ratio, and small particle size. The high concentration is linear glue. Linear glue fracturing has certain drag reduction, high sand carrying, and high cost.

[0003] Most of my country's unconventional oil and gas reservoirs are characterized by low permeability, density and low production, and the investment benefits are marginal. Reducing the investment cost of single well production and construction is an important way to improve the benefits and reduce the investment risks of unconventional oil and gas reservoirs. The simpler the fracturing construction process and system, the lower the cost. At present, the main agent of the on-site variable viscosity fracturing fluid is a drag reducer, which is divided into three types: suspension type, inverse type and powder. Among them, the inverse emulsion drag reducer is mostly not salt-tolerant. Most of my country's unconventional oil and gas reservoirs are mountainous, hilly and desert, and water resources are scarce. Volume fracturing itself has a large amount of liquid. If a large amount of clean water is used, it will cause great pressure on local water resources. Due to the slow dissolution of powder drag reducers, mixing vehicles must be used to prepare the liquid, and a large number of buffer tanks are used for buffering. Some mountain well sites cannot meet the construction requirements due to the small site. At present, the main agent of the variable viscosity fracturing fluid is mostly composed of a suspension drag reducer combined with various additives (drainage aids, clay stabilizers, bactericides and cross-linking agents), but the more types of additives, the more complicated the on-site process and the greater the cost. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a multifunctional mixing-free fully suspended drag reducing agent and a preparation method and application thereof. The multifunctional mixing-free fully suspended drag reducing agent of the present invention is a multifunctional suspended drag reducing agent, which can realize the integrated functions of salt-resistant drag reduction, sand carrying, anti-swelling, drainage assistance and sterilization without additional auxiliary agents.

[0005] The technical solution adopted to solve the technical problem is to provide a multifunctional mixing-free fully suspended drag reducing agent, comprising the following raw materials in parts by weight: 30-50 parts of partially hydrolyzed polyacrylamide, 35-60 parts of white oil, 2-5 parts of anionic surfactant, 0-3 parts of bactericide, 0.5-2 parts of organic clay, 0.5-1.5 parts of alcohol compound and 1-3 parts of emulsifier.

[0006] The beneficial effects of the technical scheme adopted in the present invention are as follows: the multifunctional non-mixing fully suspended drag reducer of the present invention can realize multiple functions with one dose by using the proportion of each raw material component without additional additives when used on site, thereby greatly improving the construction efficiency and convenience; the drag reducer not only has excellent drag reduction performance, but also has multiple functions such as salt resistance, sand carrying, anti-swelling, drainage assistance and sterilization, and can be widely used in the field of fracturing construction, effectively reducing construction pump pressure and energy consumption, and improving overall construction efficiency; the partially hydrolyzed polyacrylamide used in the present invention can play a role in salt resistance and drag reduction; white oil can wrap partially hydrolyzed polyacrylamide as a suspension system carrier, so that it can be evenly dispersed in water during the preparation of the slippery water system; alcohol compounds can improve the dispersion of organic clay in white oil, and the surfactant configured as a slippery water synergistic system can further reduce its surface tension; emulsifiers help organic clay and other raw materials to form a network structure, so that the overall drag reducer is more uniform and integrated.

[0007] Preferably, the multifunctional mixing-free fully suspended drag reducing agent comprises the following raw materials in parts by weight: 30-45 parts of partially hydrolyzed polyacrylamide, 45-60 parts of white oil, 2.5 parts of anionic surfactant, 2.5 parts of bactericide, 1-2 parts of organic clay, 0.5-1 part of alcohol compound and 2.5-3 parts of emulsifier.

[0008] More preferably, the molecular weight of the partially hydrolyzed polyacrylamide is 28 to 35 million, the degree of hydrolysis is 20 to 30%, the particle size is 100 to 120 meshes, and the content of 2-acrylamido-2-methylpropanesulfonic acid in the partially hydrolyzed polyacrylamide is 0 to 15%.

[0009] More preferably, the white oil is 5# white oil, 7# white oil, 10# white oil or 15# white oil.

[0010] More preferably, the anionic surfactant is sodium perfluorononenyloxybenzenesulfonate.

[0011] The beneficial effects of the above technical solution adopted in the present invention are as follows: sodium perfluorononenyloxybenzene sulfonate is selected as an anionic surfactant, which has more unique and excellent properties compared to other common anionic surfactants, such as sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (LAS), etc. First, due to the high electronegativity and low polarizability of fluorine atoms, sodium perfluorononenyloxybenzene sulfonate has weak intermolecular forces and extremely low surface tension, so it has stronger surface activity; secondly, sodium perfluorononenyloxybenzene sulfonate has excellent chemical stability and can resist corrosion from a variety of chemical substances such as acids, alkalis, and oxidants, so that it can maintain its performance stability in a variety of harsh environments. At the same time, it also has certain antistatic properties and temperature resistance, and has a good use effect.

[0012] More preferably, the fungicide is 2,2-dibromo-3-nitrilopropionamide or 2,2-dibromo-2-nitroethanol.

[0013] The beneficial effects of the technical scheme adopted in the present invention are as follows: 2,2-dibromo-3-nitrilopropionamide and 2,2-dibromo-2-nitroethanol can effectively inhibit and kill a variety of microorganisms such as bacteria, molds, yeasts, etc.; adding 2,2-dibromo-3-nitrilopropionamide or 2,2-dibromo-2-nitroethanol to the drag reducing agent can significantly reduce the risk of microbial contamination and has a good bactericidal effect; secondly, 2,2-dibromo-3-nitrilopropionamide or 2,2-dibromo-2-nitroethanol has a long lasting effect, can maintain bactericidal activity for a long time, and has a long preservation time in the drag reducing agent; at the same time, 2,2-dibromo-3-nitrilopropionamide or 2,2-dibromo-2-nitroethanol has good compatibility with other components in the drag reducing agent, can be evenly dispersed in the drag reducing agent system to form a stable suspension.

[0014] More preferably, the alcohol compound is ethanol, methanol, ethylene glycol or glycerol.

[0015] The beneficial effects of the technical solution adopted in the present invention are as follows: in the drag reducing agent system, the addition of alcohol compounds helps to disperse the organic clay to form a more uniform and stable suspension, thereby improving the overall performance of the drag reducing agent; at the same time, during fracturing construction, the alcohol compounds in the slippery water can coordinate with sodium perfluorononenyloxybenzenesulfonate to reduce the surface tension of the liquid, which helps to flow back, reduce secondary damage to the formation, and improve the fracturing construction effect.

[0016] More preferably, the emulsifier is at least one of the condensate of fatty alcohol and ethylene oxide AEO-5, the condensate of alkylphenol and ethylene oxide OP-10, sorbitan fatty acid ester S-80 and polyoxyethylene sorbitan fatty acid ester T-80.

[0017] The present invention also provides a method for preparing the multifunctional mixing-free fully suspended drag reducing agent, comprising the following steps: At room temperature, partially hydrolyzed polyacrylamide, white oil, anionic surfactant, bactericide, organic clay, alcohol compound and emulsifier are added into a reaction kettle in proportion, and stirred at a speed of 110-130 rpm for 1.5-2.5 h to obtain the product.

[0018] More preferably, the preparation method of the multifunctional mixing-free fully suspended drag reducing agent comprises the following steps: At room temperature, partially hydrolyzed polyacrylamide, white oil, anionic surfactant, bactericide, organic clay, alcohol compound and emulsifier are added into a reaction kettle in proportion, and stirred at 120 rpm for 2 h to obtain the product.

[0019] The present invention also provides application of the multifunctional non-mixing fully suspended drag reducing agent in a fracturing fluid system.

[0020] The present invention has the following beneficial effects: (1) The multifunctional, non-mixing, fully suspended drag reducing agent prepared by the present invention can be formulated into different slippery water systems according to actual needs, which is suitable for the needs of different construction scenarios. It can achieve salt resistance drag reduction, sand carrying, anti-swelling, drainage assistance and sterilization without the need for additional auxiliary agents. The on-site process is simple, it can be used immediately after injection, and the cost is low.

[0021] (2) The preparation method of the multifunctional non-mixing fully suspended drag reducing agent of the present invention is simple and efficient, easy to operate and promote, and can save manpower and construction costs such as proportional pumps when used on site. DETAILED DESCRIPTION

[0022] The features and performance of the present invention are further described in detail below in conjunction with embodiments.

[0023] Example 1 A multifunctional mixing-free fully suspended drag reducing agent comprises the following raw materials in parts by weight: 40 parts of partially hydrolyzed polyacrylamide, 52.5 parts of 15# white oil, 2.5 parts of sodium perfluorononenyloxybenzene sulfonate, 1 part of organic clay, 1 part of methanol, 1.5 parts of polyoxyethylene sorbitan fatty acid ester T-80 and 1.5 parts of sorbitan fatty acid ester S-80; Among them, the molecular weight of the partially hydrolyzed polyacrylamide is 32 million, the degree of hydrolysis is 25%, the particle size is 100~120 mesh, and the content of 2-acrylamido-2-methylpropane sulfonic acid in the partially hydrolyzed polyacrylamide is 0%.

[0024] The multifunctional non-mixing fully suspended drag reducing agent in this embodiment is prepared by the following steps: At room temperature, partially hydrolyzed polyacrylamide, 15# white oil, sodium perfluorononenyloxybenzenesulfonate, organic clay, methanol, polyoxyethylene sorbitan fatty acid ester T-80 and sorbitan fatty acid ester S-80 are added into a reaction kettle in proportion, and the mixture is stirred at 120 rpm for 2 h to obtain the product.

[0025] This embodiment also includes the use of the prepared multifunctional non-mixing fully suspended drag reducing agent in a fracturing fluid system, comprising the following steps: Use the multifunctional, non-mixing, fully suspended drag reducing agent in the fracturing fluid system; The main technology of shale gas wells in a certain area of ​​Sichuan adopts perforation bridge plug combination, large section multi-cluster, variable viscosity, temporary plugging and diversion fracturing transformation technology. The main body of the fracturing fluid system uses a low-viscosity slippery water system, of which low-viscosity slippery water accounts for 90%, medium-viscosity linear glue accounts for 4%, and high-viscosity linear glue accounts for 6%; low-viscosity slippery water, medium-viscosity linear glue and high-viscosity linear glue are prepared with clean water on site, of which the mass ratio of the multifunctional non-mixing fully suspended drag reducer to water in the low-viscosity slippery water is 0.1:99.9, and the viscosity of the low-viscosity slippery water system is 4.1 m 2 / s, surface tension 27.12 mN / m, interfacial tension 1.12 mN / m; the mass ratio of the multifunctional non-mixing fully suspended drag reducing agent to water in the medium-viscosity linear adhesive is 0.2~0.3:99.7~99.8, the viscosity of the medium-viscosity linear adhesive system is 10~20 mPa·s, the surface tension is 26.14 mN / m, and the interfacial tension is 0.2mN / m; the mass ratio of the multifunctional non-mixing fully suspended drag reducing agent to water in the high-viscosity linear adhesive is 0.6~0.8:99.2~99.4, the viscosity of the high-viscosity linear adhesive system is 50~100 mPa·s, the surface tension is 25.72 mN / m, and the interfacial tension is 0.12 mN / m.

[0026] The proppant is made of 70-mesh quartz sand and 40-mesh ceramsite, with a mass ratio of quartz sand to ceramsite of 8:2. The continuous sand adding method is adopted, with an average sand adding strength of 3.0 t / m and an average liquid strength of 24.3 m 3 / m; On-site construction pressure is gentle 90~104 MPa, and the maximum sand addition amount is 380 kg / m 3 After compression, the gas production is 210,000 cubic meters per day.

[0027] Example 2 A multifunctional mixing-free fully suspended drag reducing agent, comprising the following raw materials in parts by weight: 45 parts of partially hydrolyzed polyacrylamide, 45 parts of 5# white oil, 2.5 parts of sodium perfluorononenyloxybenzenesulfonate, 2.5 parts of 2,2-dibromo-3-nitrilopropionamide, 1.5 parts of organic clay, 0.5 parts of methanol, 1.5 parts of polyoxyethylene sorbitan fatty acid ester T-80 and 1.5 parts of sorbitan fatty acid ester S-80; Among them, the molecular weight of the partially hydrolyzed polyacrylamide is 28 million, the degree of hydrolysis is 25.6%, the particle size is 100~120 mesh, and the content of 2-acrylamido-2-methylpropane sulfonic acid in the partially hydrolyzed polyacrylamide is 15%.

[0028] The multifunctional non-mixing fully suspended drag reducing agent in this embodiment is prepared by the following steps: At room temperature, partially hydrolyzed polyacrylamide, 5# white oil, sodium perfluorononenyloxybenzenesulfonate, 2,2-dibromo-3-nitrilopropionamide, organic clay, methanol, polyoxyethylene sorbitan fatty acid ester T-80 and sorbitan fatty acid ester S-80 were added into a reaction kettle in proportion, and the mixture was stirred at 120 rpm for 2 h to obtain the product.

[0029] This embodiment also includes the use of the prepared multifunctional non-mixing fully suspended drag reducing agent in a fracturing fluid system, comprising the following steps: Use the multifunctional, non-mixing, fully suspended drag reducing agent in the fracturing fluid system; The main technology of shale gas wells in a certain area of ​​Sichuan adopts perforation bridge plug combination, large section multi-cluster, variable viscosity, temporary plugging and diversion fracturing transformation technology. The main fracturing fluid system uses a low-viscosity slippery water system, of which low-viscosity slippery water accounts for 75%, medium-viscosity linear glue accounts for 15%, and high-viscosity linear glue accounts for 10%; low-viscosity slippery water, medium-viscosity linear glue and high-viscosity linear glue use full sewage on site (total salt content TDS: 2.8×10 4 The mass ratio of the multifunctional non-mixing fully suspended drag reducing agent in low-viscosity slippery water to the whole sewage is 0.1:99.9, and the viscosity of the low-viscosity slippery water system is 3.2 m 2 / s, surface tension 27.62 mN / m, interfacial tension 1.52mN / m; the mass ratio of the multifunctional non-mixing fully suspended drag reducing agent in the medium-viscosity linear adhesive to the whole sewage is 0.2~0.3:99.7~99.8, the viscosity of the medium-viscosity linear adhesive system is 10~20 mPa·s, the surface tension is 26.14 mN / m, and the interfacial tension is 0.2 mN / m; the mass ratio of the multifunctional non-mixing fully suspended drag reducing agent in the high-viscosity linear adhesive to the whole sewage is 0.6~1:99.4~99.0, the viscosity of the high-viscosity linear adhesive system is 50~100 mPa·s, the surface tension is 25.72 mN / m, and the interfacial tension is 0.12 mN / m.

[0030] The proppant is made of 70-mesh quartz sand and 40-mesh ceramsite, with a mass ratio of quartz sand to ceramsite of 8:2. The continuous sand adding method is adopted, with an average sand adding strength of 3.5 t / m and an average liquid strength of 25 m 3 / m; On-site construction pressure is gentle 90~104 MPa, and the maximum sand addition amount is 420 kg / m 3 After compression, the gas production is 451,000 cubic meters per day.

[0031] Example 3 A multifunctional, non-mixing, fully suspended drag reducing agent, comprising the following raw materials in parts by weight: 45 parts of partially hydrolyzed polyacrylamide, 45 parts of 7# white oil, 2.5 parts of sodium perfluorononenyloxybenzenesulfonate, 2.5 parts of 2,2-dibromo-3-nitrilopropionamide, 1.5 parts of organic clay, 0.5 parts of ethanol, and 2.5 parts of AEO-5, a condensate of fatty alcohol and ethylene oxide; Among them, the molecular weight of the partially hydrolyzed polyacrylamide is 28 million, the degree of hydrolysis is 25.2%, the particle size is 100~120 mesh, and the content of 2-acrylamido-2-methylpropanesulfonic acid in the partially hydrolyzed polyacrylamide is 10%.

[0032] The multifunctional non-mixing fully suspended drag reducing agent in this embodiment is prepared by the following steps: At room temperature, partially hydrolyzed polyacrylamide, 7# white oil, sodium perfluorononenyloxybenzenesulfonate, 2,2-dibromo-3-nitrilopropionamide, organic clay, ethanol and fatty alcohol and ethylene oxide condensate AEO-5 are added into a reaction kettle in proportion, and the mixture is stirred at 120 rpm for 2 h to obtain the product.

[0033] This embodiment also includes the use of the prepared multifunctional non-mixing fully suspended drag reducing agent in a fracturing fluid system, comprising the following steps: Use the multifunctional, non-mixing, fully suspended drag reducing agent in the fracturing fluid system; The main technology of shale gas wells in a certain area of ​​Sichuan adopts perforation bridge plug combination, large section multi-cluster, variable viscosity, temporary plugging and diversion fracturing transformation technology. The main fracturing fluid system uses a low-viscosity slickwater system, of which low-viscosity slickwater accounts for 65%, frozen gel fracturing fluid accounts for 20%, and medium-viscosity linear gel accounts for 15%; low-viscosity slickwater, frozen gel fracturing fluid and medium-viscosity linear gel use full sewage on site (TDS: 1.2×10 4 The mass ratio of the multifunctional non-mixing fully suspended drag reducing agent in low-viscosity slippery water to the whole sewage is 0.1:99.9, and the viscosity of the low-viscosity slippery water system is 3.8 m 2 / s, surface tension 27.22 mN / m, interfacial tension 1.32 mN / m; the mass ratio of the multifunctional non-mixing fully suspended drag reducing agent to the whole sewage in the medium-viscosity linear glue is 0.2~0.3:99.7~99.8, the viscosity of the medium-viscosity linear glue system is 10~20 mPa·s, the surface tension is 26.44 mN / m, and the interfacial tension is 0.15 mN / m; the mass ratio of the multifunctional non-mixing fully suspended drag reducing agent, the organic zirconium cross-linking agent and the whole sewage in the gel fracturing fluid is 0.6:0.3:99.1, the base fluid viscosity of the gel fracturing fluid system is 34 mPa·s, the cross-linking time is 120 s, the temperature and shear resistance (120℃, 2 h, 170 -s ) 65 MPa.s, surface tension after breaking 26.4 mN / m, interfacial tension 0.52 mN / m.

[0034] The proppant is made of 70-mesh quartz sand and 40-mesh ceramsite, with a mass ratio of quartz sand to ceramsite of 8:2. The continuous sand adding method is adopted, with an average sand adding strength of 4.1 t / m and an average liquid strength of 30 m 3 / m; On-site construction pressure is gentle 90~104 MPa, and the maximum sand addition amount is 520 kg / m 3 After compression, the gas production is 238,000 cubic meters per day.

[0035] Example 4 A multifunctional, non-mixing, fully suspended drag reducing agent, comprising the following raw materials in parts by weight: 30 parts of partially hydrolyzed polyacrylamide, 60 parts of 7# white oil, 2.5 parts of sodium perfluorononenyloxybenzenesulfonate, 2.5 parts of 2,2-dibromo-3-nitrilopropionamide, 2 parts of organic clay, 0.5 parts of glycerol, and 2.5 parts of AEO-5, a condensate of fatty alcohol and ethylene oxide; Among them, the molecular weight of the partially hydrolyzed polyacrylamide is 28 million, the degree of hydrolysis is 25.2%, the particle size is 100~120 mesh, and the content of 2-acrylamido-2-methylpropanesulfonic acid in the partially hydrolyzed polyacrylamide is 5%.

[0036] The multifunctional non-mixing fully suspended drag reducing agent in this embodiment is prepared by the following steps: At room temperature, partially hydrolyzed polyacrylamide, 7# white oil, sodium perfluorononenyloxybenzenesulfonate, 2,2-dibromo-3-nitrilopropionamide, organic clay, glycerol and fatty alcohol and ethylene oxide condensate AEO-5 are added into a reaction kettle in proportion and stirred at 120 rpm for 2 h to obtain the product.

[0037] This embodiment also includes the use of the prepared multifunctional non-mixing fully suspended drag reducing agent in a fracturing fluid system, comprising the following steps: Use the multifunctional, non-mixing, fully suspended drag reducing agent in the fracturing fluid system; The main technology of shale gas wells in a certain area of ​​Sichuan adopts perforation bridge plug combination, large section multi-cluster, variable viscosity, temporary plugging and diversion fracturing transformation technology. The main fracturing fluid system uses a low-viscosity slickwater system, of which low-viscosity slickwater accounts for 95% and medium-viscosity linear glue accounts for 5%. The low-viscosity slickwater and medium-viscosity linear glue use full sewage on site (TDS: 1.1×10 4 The mass ratio of the multifunctional non-mixing fully suspended drag reducing agent in low-viscosity slippery water to the whole sewage is 0.1:99.9, and the viscosity of the low-viscosity slippery water system is 3.2 m 2 / s, surface tension 27.32 mN / m, interfacial tension 1.02 mN / m; the mass ratio of the multifunctional non-mixing fully suspended drag reducing agent to the whole sewage in the medium-viscosity linear adhesive is 0.2~0.3:99.7~99.8, the viscosity of the medium-viscosity linear adhesive system is 10~20 mPa·s, the surface tension is 26.44 mN / m, and the interfacial tension is 0.15 mN / m.

[0038] The proppant is made of 70-mesh quartz sand and 40-mesh ceramsite, with a mass ratio of quartz sand to ceramsite of 8:2. The continuous sand adding method is adopted, with an average sand adding strength of 3.5 t / m and an average liquid strength of 35 m 3 / m; On-site construction pressure is gentle 80~97 MPa, and the maximum sand addition amount is 320 kg / m 3 After compression, the gas production is 165,000 cubic meters per day.

[0039] Comparative Example 1 A multifunctional mixing-free fully suspended drag reducing agent, which differs from Example 3 in that the sodium perfluorononenyloxybenzenesulfonate in the formula of Example 3 is replaced by sodium dodecylbenzenesulfonate, and the remaining raw materials and steps are the same as those of Example 3.

[0040] Comparative Example 2 A multifunctional mixing-free fully suspended drag reducing agent, which differs from Example 3 in that the weight portion of sodium perfluorononenyloxybenzenesulfonate in the formula is 1 part, and the remaining raw materials and steps are the same as those in Example 3.

[0041] Comparative Example 3 A multifunctional, mix-free, fully suspended drag reducing agent is disclosed. The difference from Example 3 is that ethanol is not added to the formula of Example 3, and the remaining raw materials and steps are the same as those of Example 3.

[0042] Comparative Example 4 A multifunctional, mix-free, fully suspended drag reducing agent, which differs from Example 3 in that 2,2-dibromo-3-nitrilopropionamide in the formula of Example 3 is replaced by dodecyl dimethyl benzyl ammonium chloride, and the remaining raw materials and steps are the same as those of Example 3.

[0043] Comparative Example 5 A multifunctional mixing-free fully suspended drag reducing agent is disclosed, which is different from Example 3 in that the content of 2-acrylamido-2-methylpropanesulfonic acid in the partially hydrolyzed polyacrylamide in the formula of Example 3 is 0%, and the remaining raw materials and steps are the same as those of Example 1.

[0044] Comparative Example 6 A multifunctional, mix-free, fully suspended drag reducing agent is disclosed. The difference between the invention and embodiment 3 is that 2,2-dibromo-3-nitrilopropionamide is not added to the formula of embodiment 3, and the remaining raw materials and steps are the same as those of embodiment 1.

[0045] Experimental example The physical and chemical properties of the multifunctional non-mixing fully suspended drag reducing agent obtained in Example 3 and Comparative Examples 1 to 6 were tested. The test method is as follows. The results are shown in Table 1.

[0046] a. Stability test: The drag reducing agents prepared in Example 3 and Comparative Examples 1 to 6 were placed at room temperature to observe the settling of the drag reducing agents; b. Tests of viscosity, drag reduction rate, surface tension and interfacial tension: The drag reducing agents prepared in Example 3 and Comparative Examples 1 to 6 were respectively prepared with 0.1% low-viscosity slippery water using on-site water, and their viscosity, drag reduction rate, surface tension and interfacial tension were measured.

[0047] Table 1 Test results of drag reducing agent performance

[0048] From the application of the multifunctional non-mixing fully suspended drag reducing agent in the fracturing fluid system in Examples 1 to 4 and Table 1 thereof, it can be seen that the multifunctional non-mixing fully suspended drag reducing agent prepared by the present invention can be formulated into different slippery water systems according to actual needs, suitable for the needs of different construction scenes, and has super salt resistance in one dose. No additional bactericide and drainage agent are required for on-site use, and a variable viscosity system can be achieved in one dose, and the stability and drag reducing effect are good. In Comparative Example 1, after replacing sodium perfluorononenyloxybenzenesulfonate with sodium dodecylbenzenesulfonate, the surface and interfacial tension of the drag reducing agent is significantly increased, and the surface tension ≤28 mN / m and interfacial tension ≤2 mN / m product requirements cannot be met; in Comparative Example 3, if ethanol is not added, the sedimentation stability of the drag reducing agent suspension system will be affected, causing it to settle after being placed for 20 days; in Comparative Example 4, replacing 2,2-dibromo-3-nitrilopropionamide with dodecyl dimethyl benzyl ammonium chloride will greatly affect the use of the drag reducing agent, and easily cause the drag reducing agent to flocculate.

[0049] The present invention has been described according to the above embodiments. It should be understood that the above embodiments do not limit the present invention in any form. Any technical solutions obtained by equivalent replacement or equivalent transformation shall fall within the scope of the present invention.

Claims

1. A multifunctional, non-mixing, fully suspended drag reducing agent, characterized in that: The invention comprises the following raw materials in parts by weight: 30-50 parts of partially hydrolyzed polyacrylamide, 35-60 parts of white oil, 2-5 parts of anionic surfactant, 0-3 parts of bactericide, 0.5-2 parts of organic clay, 0.5-1.5 parts of alcohol compound and 1-3 parts of emulsifier.

2. The multifunctional non-mixing fully suspended drag reducing agent according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 30-45 parts of partially hydrolyzed polyacrylamide, 45-60 parts of white oil, 2.5 parts of anionic surfactant, 2.5 parts of bactericide, 1-2 parts of organic clay, 0.5-1 parts of alcohol compound and 2.5-3 parts of emulsifier.

3. The multifunctional non-mixing fully suspended drag reducing agent according to claim 1 or 2, characterized in that: The molecular weight of the partially hydrolyzed polyacrylamide is 28 to 35 million, the degree of hydrolysis is 20 to 30%, the particle size is 100 to 120 meshes, and the content of 2-acrylamido-2-methylpropane sulfonic acid in the partially hydrolyzed polyacrylamide is 0 to 15%.

4. The multifunctional non-mixing fully suspended drag reducing agent according to claim 1 or 2, characterized in that: The white oil is 5# white oil, 7# white oil, 10# white oil or 15# white oil.

5. The multifunctional non-mixing fully suspended drag reducing agent according to claim 1 or 2, characterized in that: The anionic surfactant is sodium perfluorononenyloxybenzenesulfonate.

6. The multifunctional non-mixing fully suspended drag reducing agent according to claim 1 or 2, characterized in that: The bactericide is 2,2-dibromo-3-nitrilopropionamide or 2,2-dibromo-2-nitroethanol.

7. The multifunctional non-mixing fully suspended drag reducing agent according to claim 1 or 2, characterized in that: The alcohol compound is ethanol, methanol, ethylene glycol or glycerol.

8. The multifunctional non-mixing fully suspended drag reducing agent according to claim 1 or 2, characterized in that: The emulsifier is at least one of the following: AEO-5, a condensate of fatty alcohol and ethylene oxide, OP-10, a condensate of alkylphenol and ethylene oxide, S-80, a sorbitan fatty acid ester, and T-80, a polyoxyethylene sorbitan fatty acid ester.

9. The method for preparing the multifunctional mixing-free fully suspended drag reducing agent according to any one of claims 1 to 8, characterized in that: The following steps are involved: At room temperature, partially hydrolyzed polyacrylamide, white oil, anionic surfactant, bactericide, organic clay, alcohol compound and emulsifier are added into a reaction kettle in proportion, and stirred at a speed of 110-130 rpm for 1.5-2.5 h to obtain the product.

10. Use of the multifunctional, non-mixing, fully suspended drag reducing agent according to any one of claims 1 to 8 in a fracturing fluid system.

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