253 results about "Drag reducing agent" patented technology

The invention provides a cement paste system with high strength, elasticity and toughness and application of the cement paste system in deep coal bed gas horizontal well cementation, and the cement paste system is prepared from the following raw materials in parts by mass: 40-70 parts of oil well cement, 13-40 parts of fly ash, 15-45 parts of slag, 5.0-20.0 parts of water-based organic silicon resin, 0.1-0.5 part of ultra-high performance polyethylene fiber, 3.0-8.0 parts of calcium oxide and 2.0-5.0 parts of calcium sulfate whisker. 1.0-8.0 parts of nano silicon dioxide, 1.0-6.0 parts of a fluid loss agent, 0.5-2.0 parts of a drag reducer, 0.2-1 part of a defoaming agent and 50-80 parts of water. The cement paste system disclosed by the invention has the characteristics of remarkable low-temperature quick setting and high early strength, also has the advantages of low water loss, controllable thickening, simple preparation operation and the like, and set cement is high in compressive strength, high in breaking strength and very excellent in elastic and tough mechanical properties.

The invention relates to the technical field of oil and gas field exploitation, and discloses a drag reducer for a multifunctional fracturing fluid and a preparation method thereof.The preparation method of the drag reducer for the multifunctional fracturing fluid comprises the steps that acrylic acid, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and modified itaconic acid are added into deionized water, stirring and mixing are conducted, and the drag reducer for the multifunctional fracturing fluid is obtained. Nitrogen is introduced for 30-40 min to remove oxygen, then azobis (isobutylamidine) hydrochloride is added, the mixture is stirred to react for 48-72 h at the temperature of 45-50 DEG C, and a polymer solution is obtained; and directly and uniformly mixing the polymer solution, the compatilizer and the modified nano silicon dioxide, and reacting in a magnetic stirrer at 60-70 DEG C for 1.5-2 hours to obtain the drag reducer for the multifunctional fracturing fluid. The drag reducer has a good drag reduction effect, and the hydrophobicity, the temperature resistance, the salt resistance and the shear resistance are improved.

The invention discloses a carbon dioxide injection and production well cementation cement paste and a preparation method and application thereof, the well cementation cement paste comprises the following components by weight: 95-105 parts of oil well cement, 44-48 parts of water, 4-6 parts of a polymer emulsion, 4-6 parts of a self-repairing material, 1.5-2.5 parts of a drag reducer, 0.5-1.5 parts of a fluid loss agent and 0.2-0.8 part of an antifoaming agent; wherein the polymer emulsion is an emulsion which is formed by taking methyl methacrylate, vinyl trimethoxy silane and propylene carbonate as monomers through polymerization; the self-repairing material is a microcapsule in which thiobacillus ferrooxidans thalli and bacillus amyloliquefaciens thalli are embedded. The well cementation cement paste keeps good strength and relatively low permeability in a carbon dioxide environment, is good in corrosion resistance and has self-repairing capability.

The invention provides a dry powder drag reducer for fracturing fluid and a preparation method of the dry powder drag reducer, and belongs to the technical field of fracturing materials for well drilling, and the preparation method comprises the following steps: dissolving 4-bromobutyryl chloride and N-dodecyl methylamine in acetonitrile, heating and stirring for reaction, adding polyethylene glycol monomethyl ether acrylate and dichloromethane, stirring and purifying in a nitrogen atmosphere to obtain a dry powder drag reducer; a double-tailed hydrophobic monomer is obtained; uniformly mixing the core-shell SiO2 / Fe3O4 composite nanoparticles, an ethanol water solution, KH570 and an ammonia solution, stirring, and purifying to obtain modified SiO2 / Fe3O4; the preparation method comprises the following steps: adding acrylamide, acrylic acid, sodium 2-acrylamido-2-methylpropanesulfonate, a double-tailed hydrophobic monomer and modified SiO2 / Fe3O4 into water, uniformly mixing, adjusting the pH value, introducing nitrogen, mixing and stirring, adding an azo initiator, stirring, cooling, purifying, carrying out vacuum drying, and crushing into powder, thereby obtaining the dry powder drag reducer for the fracturing fluid. The drag reducer has certain heat resistance while achieving good drag reduction performance, and can be better applied to fracturing operation in the well drilling process.

The invention relates to a method for preparing a degradable polyacrylamide fracturing fluid through an RAFT (Reversible Addition-Fragmentation Chain Transfer) polymerization method. According to the method, a chain transfer reagent-RAFT reagent is used during synthesis of a macromolecular chain, and after the chain transfer reagent is added, the reaction rate can be effectively reduced, and gelation is avoided; the control on the molecular weight can be ensured; after the primary amine is added, a C-S bond in the RAFT reagent is converted into sulfydryl which is further oxidized into a dynamic disulfide bond in air, the molecular weight of the fracturing fluid is doubled, and the drag reduction performance of the fracturing fluid is effectively improved; after the reducing agent is added, the disulfide bond is broken, the molecular weight is rapidly reduced, and after the oxidizing agent is added, the molecular weight can be rapidly increased. The obtained linear drag reducer can reach the degradation rate of 87% or above, and has important significance on exploration and development of oil and gas resources.

The invention discloses a water-non-dispersible cement paste system for well cementation. The water-non-dispersible cement paste system comprises the following components in parts by weight: 100 parts of oil well cement, 2-3 parts of an expanding agent, 1-5 parts of an anti-dispersing agent, 0.5-2 parts of a drag reducer, 0-0.1 part of a defoaming agent and 40-45 parts of water, the anti-dispersing agent is formed by copolymerizing the following components in percentage by mass: 15 to 60 weight percent of acrylic acid, 0 to 15 weight percent of N, N-dimethyl acrylamide, 30 to 85 weight percent of acrylamide, 0 to 10 weight percent of N-vinyl pyrrolidone and 0 to 1.5 weight percent of ethylene diamine tetraacetic acid disodium salt; the drag reducer is obtained by graft polymerization of a polyacrylic acid monomer and fatty acid vinyl ester in a molar ratio of (8-36): 1; the polyacrylic acid monomer is formed by copolymerizing 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, sodium p-styrenesulfonate and acrylamide according to a molar ratio of (0.08 to 0.6): 1: (0.05 to 0.3): (0.1 to 1); the water non-dispersible cement paste system for well cementation has good dispersion resistance and flowing property, and the water invasion resistance of the cement paste is effectively improved.

The invention discloses a flexible anti-fouling and anti-drag composite coating with temperature responsiveness and a preparation method and application of the flexible anti-fouling and anti-drag composite coating. The flexible antifouling anti-drag composite coating comprises a substrate layer, a flexible buffer layer, an antifouling response layer and a hydrophobic surface layer which are sequentially formed on the surface of a base material, wherein the substrate layer comprises adhesive resin, a positively charged polymer and a particle filler; the flexible buffer layer comprises flexible polymer resin, a negatively charged polymer, a polymer drag reducer and an anti-ultraviolet additive; the hydrophobic surface layer comprises flexible polymer resin, a temperature-responsive polymer microcapsule encapsulated with an antifouling agent, a pore-foaming agent, an anti-ultraviolet additive and super-hydrophobic micro-nano particles. The flexible anti-fouling and anti-drag composite coating with temperature responsiveness provided by the invention has strong binding force with a base material, and also has anti-fouling property, corrosion protection property and anti-drag property; meanwhile, the preparation method provided by the invention has the advantages of wide application range, large-area coating and the like.

The invention discloses deep coal bed gas well cementation cement paste and a preparation method thereof, and the deep coal bed gas well cementation cement paste is prepared from the following raw materials in parts by weight: 100 parts of G-grade oil well cement, 5-15 parts of water-borne epoxy resin, 1.5-3 parts of a nano silicon dioxide solution, 0.5-1.8 parts of calcium sulfate whiskers, 0.2-0.6 part of composite coating fibers, 1.2-1.8 parts of a fluid loss agent and 0.5-1.8 parts of a retarder. 0.3 to 0.5 part of a drag reducer, 0.2 to 0.5 part of a defoaming agent and 38 to 42 parts of water; wherein the composite coating fiber is hydrophilic epoxy resin modified polyethylene fiber. The cement paste can improve the well cementation cementing packing quality of a coal seam, and has good filtration property.

A treatment fluid for oilfield applications, such as matrix acidizing and acid fracturing. The treatment fluid is a two-phase fluid with an hydrophobic continuous phase and an at least partially dispersed water phase. The hydrophobic continuous phase can contain 1 ppm to 10 wt %, based on the total weight of the treatment fluid, of one or more types of oil-soluble DRAs having a weight average molecular weight greater than 200,000. The at least partially dispersed water phase can contain water and one or more reactive acids having a pH of 4 or less than 4.

The invention discloses a polymer shear degradation evaluation method based on an FENE-P model, and belongs to the field of polymer turbulence drag reduction. The method comprises the following steps: carrying out a polymer degradation influence factor experiment based on a polymer degradation loop experiment device, and calculating a degradation rate; carrying out a viscous shear rheological experiment aiming at solutions at different degradation stages; fitting rheological experiment data, and establishing a rheological equation; determining viscoelastic parameters in the FENE-P model, correcting a momentum equation and a molecular deformation transport equation, and compiling a related UDF file; loading the UDF file into a source item, a transient item and a convection item of a fluid domain of FLUENT software, and changing relevant viscoelastic parameters of an FENET-P model to realize polymer fluid degradation flow field simulation; and analyzing the flow field information difference between the Newtonian fluid and the FENE-P solution, evaluating the shear degradation behavior of the polymer flowing from a macroscopic flow field to a microcosmic flow field, and explaining the shear degradation mechanism of the polymer. The method provided by the invention provides a theoretical basis for optimization of the polymer drag reducer in actual fluid turbulence transportation.

The invention provides an environment-friendly efficient energizing flushing fluid. The flushing fluid comprises hydrochloric acid, a base fluid A, an energizing capsule B and a catalytic capsule C, the base solution A is prepared from the following components in parts by mass: 100 parts of water serving as a dispersion medium, 0.5 to 1 part of an emulsifier, 0.5 to 1 part of a surfactant, 1 to 2 parts of a cosurfactant, 5 to 10 parts of a mutual solvent, 0.03 to 0.08 part of a drag reducer, 25 to 45 parts of an organic solvent, 0.05 to 0.1 part of a bactericide and 0.3 to 0.5 part of a scale inhibitor; an energy increasing agent CO (NH2) 2 and an energy increasing agent NH4Cl; the energizing capsule B comprises a capsule core and a capsule wall; the capsule wall is paraffin and the like; the capsule core is prepared from NaNO2 and NaHCO3; the catalytic capsule C comprises a capsule core and a capsule wall; the capsule core is oxalic acid and the like; the capsule wall is paraffin and the like. The flushing fluid has the characteristics of small flow resistance, viscosity reduction, obvious energy increase, strong chip carrying capacity, high dynamic paraffin dissolving rate, high paraffin inhibition rate, safety and environmental protection, and can realize multiple effects.

The application relates to a dry powder drag reducer for fracturing fluid and a preparation method thereof, and belongs to the technical field of drag reducers; the dry powder drag reducer is copolymerized and modified by preparing a polymerizable modifier, aromatic rings and sulfonic acid ion structures are introduced into the dry powder drag reducer, the high-temperature resistance and salt resistance of the dry powder drag reducer are effectively improved, in addition, the modified dry powder drag reducer structure also has a catechol structure, can form a stable five-membered ring borate with a boron crosslinking agent, and the dry powder drag reducer can be mixed with a guar gum drag reducer when the boron drag reducer is used, so that the problem of poor sand carrying capacity of the dry powder drag reducer is effectively solved.

The present disclosure provides a drag reducing agent. In an embodiment, the drag reducing agent includes a polymer and a liquid carrier. The polymer is composed of one or more C6-C14 α-olefin monomers. The polymer includes a residual amount of zirconium. The polymer has an absolute weight average molecular weight (Mw(Abs)) greater than 1,300,000 g / mol and a (Mw(Abs) / Mn(Abs) from 1.3 to 3.0.

The invention discloses a drag reduction composition, a preparation method thereof and a pipeline drag reducer. The drag reduction composition comprises the following components in parts by mass: 10-21 parts of a polymethacrylate compound, 6-18 parts of a dispersing agent and 2-9 parts of a lubricating agent, the lubricant is prepared from one or more of glycerol triacetate, glycerol tripropionate, pentaerythritol tetraacetate and dipentaerythritol hexaacetate. The drag reduction composition provided by the invention comprises the polymethacrylate compound matched with the dispersing agent and the specific lubricant, and the components jointly form a suspension system with stable properties, so that the degree of freedom of motion among polymer molecules can be increased, and the occurrence of an agglomeration phenomenon is reduced. When the drag reduction composition is added into a pipeline containing crude oil or product oil, polymer molecules can be stretched, folding and curling phenomena of the polymer molecules can be reduced, and a good drag reduction effect can be quickly achieved.

The invention relates to a dry powder drag reducer for fracturing fluid and a preparation method thereof, and belongs to the technical field of drag reducers. The dry powder drag reducer is subjected to copolymerization modification by preparing the polymerizable modifier, an aromatic ring and sulfonic acid ion structure is introduced into the dry powder drag reducer, the high temperature resistance and salt resistance of the dry powder drag reducer are effectively improved, in addition, the modified dry powder drag reducer structure further has a catechol structure, and the modified dry powder drag reducer has a good application prospect. The dry powder drag reducer can form stable five-membered ring boric acid ester with a boron cross-linking agent, when the boron drag reducer is used, the dry powder drag reducer can be mixed with a guar gum drag reducer for use, and the problem that the dry powder drag reducer is poor in sand carrying capacity is effectively solved.

The invention belongs to the technical field of oil exploitation, and relates to a drag reducer for fracturing and a preparation method thereof. The preparation method comprises the following steps: adding 1, 5-hexadiene-3, 4-diol and a catalyst into a high-pressure reactor, raising the temperature, introducing ethylene oxide, raising the temperature, carrying out a heat preservation reaction, stopping heating, and cooling to 50 DEG C or below; adjusting the pH value to 2-3 by using phosphoric acid, adding sulfamic acid, heating, preserving heat and reacting, and cooling to below 40 DEG C; the preparation method comprises the following steps: adding deionized water, 2-(trifluoromethyl) acrylic acid and methacryloylethyl sulphobetaine, stirring and dissolving, adjusting the pH value to 7-8, adding an initiator, heating and carrying out a heat preservation reaction to obtain a viscous liquid; and settling, centrifuging, cleaning and drying to obtain the product drag reducer. The drag reducer has the characteristics of high viscosity and high drag reduction rate.

The invention discloses a deep-sea mining plume inhibition technology using an AUV (Autonomous Underwater Vehicle) to add a flocculating agent, which comprises a mine car, a solution mixing container is arranged in the mine car, a stirrer is arranged on the solution mixing container, a second flow pump is arranged on the left side of the solution mixing container, and one end of the second flow pump is connected with the solution mixing container through a conveying pipeline; the other end of the solution mixing container is connected with a water pumping pipeline through a conveying pipeline; a jet flow pump is arranged on the left side of the solution mixing container; a flocculating agent is accurately added through the AUV, aggregation and sedimentation of suspended particulate matter are promoted, formation and diffusion of plume are effectively inhibited, pollution of deep-sea mining to the marine environment is reduced, the AUV can conduct autonomous navigation and control operation underwater, the system can adapt to the complex deep-sea environment, and the service life of the system is prolonged. The application scene of the technology is wide, the flocculant can be used for reducing plume generation, the drag reducer can also be used for reducing water jet resistance, and the mining efficiency is improved.

The invention relates to the field of oil and gas gathering and transportation, in particular to a drag reducer for oil and gas gathering and transportation and a preparation method of the drag reducer, and solves the problems that poly-alpha-olefin drag reducers are insufficient in shear resistance, and nano drag reducers are unstable in drag reduction effect and poor in drag reduction effect. Dispersing graphene oxide in an alkaline solution, dropwise adding the dispersed graphene oxide into deionized water containing carboxymethyl cellulose, adding a catalyst, and carrying out a heating reaction to obtain a miniature elastomer; the preparation method comprises the following steps: preparing a micro elastomer, oxidizing the micro elastomer to form alkali liquor containing an activated nano material, modifying the activated nano material by using a polyphenol compound, and modifying a long-chain hydrophobic structure to obtain the hydrophobic drag reducer. The oil gas drag reducer prepared by compounding the graphene oxide and the cellulose and constructing a plurality of hydrophobic long chains is excellent in drag reduction effect and high in shear resistance.

The invention discloses an underwater vehicle head structure capable of slowly releasing a drag reducer, and belongs to the field of underwater drag reduction of vehicles. Comprising a head cone section and a head circular truncated cone section which are coaxially and fixedly connected, one end of the head circular truncated cone section is in sealed connection with the head cone section, a cavity structure for containing a drag reducer solution is arranged at the joint, and the other end of the head circular truncated cone section is in sealed connection with a navigation body middle section; the head cone section is a rotary body porous medium which is close to a cone, the cone vertex of the head cone section is a molded line stagnation point which forms a conical molded surface, the axial height at the stagnation point is the largest, and the axial thickness is in a change rule of gradually decreasing from the stagnation point to the edge of the bottom end. The defects that in the prior art, a drag reducer solution cannot evenly wrap the whole vehicle, and the integrity of a shell of the vehicle is greatly damaged when the drag reducer is released are overcome.

This invention provides a dry powder drag-reducing agent for fracturing fluids and its preparation method, belonging to the technical field of fracturing materials for drilling. The method includes the following steps: dissolving 4-bromobutyryl chloride and N-dodecylmethylamine in acetonitrile, heating and stirring to react; adding polyethylene glycol monomethyl ether acrylate and dichloromethane; stirring under a nitrogen atmosphere; purifying to obtain a double-tailed hydrophobic monomer; mixing core-shell Fe3O4 / SiO2 composite nanoparticles, ethanol aqueous solution, KH570, and ammonia solution; stirring; purifying to obtain modified SiO2 / Fe3O4; adding acrylamide, acrylic acid, sodium 2-acrylamido-2-methylpropanesulfonate, the double-tailed hydrophobic monomer, and modified SiO2 / Fe3O4 to water; adjusting the pH value; mixing and stirring with nitrogen gas; adding an azo initiator; stirring; cooling; purifying; vacuum drying; and pulverizing into powder to obtain the dry powder drag-reducing agent for fracturing fluids. This invention achieves good drag-reducing performance while also possessing certain heat resistance, making it better suited for fracturing operations in drilling processes.

The invention relates to the technical field of oilfield exploitation, and discloses a preparation method of a drag reducer for a high-salt-resistance fracturing fluid. According to the preparation method, methacrylamide, acrylic acid, N-allyl imidazole, naphthyl modified sulfo modified morpholine derivatives and quaternary ammonium salt modified triazinyl pyrrolidone are polymerized in water, washed and dried, and the drag reducer for the high-salt-resistance fracturing fluid is obtained. The sulfonate radical enhances the solubility of the polymer, and enables the molecular chain skeleton of the polymer to carry more negative charges, so that the molecular chain is not easy to curl, and the salt resistance and shear resistance are improved; a hydrophobic association structure formed by introducing a long carbon chain and naphthyl on a polymer molecular chain is beneficial to association among molecules under the action of external salt, so that the salt-resistant and shear-resistant effects are enhanced; a steric effect generated by a pyrrole group, a morpholine group and a triazine group can limit hydrolysis of a primary amide group of a main chain, so that the salt resistance is improved; the quaternary ammonium salt group can increase the rigidity of a molecular chain, so that the anti-shearing performance is improved.

This invention discloses a gradient pore self-assembled drag-reducing agent for nano-fracturing fluids and its preparation method. The drag-reducing agent comprises nanoparticles with a three-layer gradient self-assembled structure, the particle size of which is no greater than 50 nm. The three-layer gradient self-assembled structure comprises, from the inside out, a hydrophobic core layer, a middle viscoelastic layer, and an outer hydrophilic layer, and is composed of the following by mass percentage: hydrophobic core layer: 25–35% nonionic surfactant, 15–20% organic solvent; middle viscoelastic layer: 30–40% polymer; outer hydrophilic layer: 15–20% zwitterionic surfactant. This invention, through its three-layer gradient self-assembled structure design, integrates multiple functions such as high-efficiency drag reduction, strong proppant carrying capacity, reservoir modification, deep penetration, and temperature and salt resistance. It comprehensively solves the technical bottlenecks of existing technologies, such as low drag reduction efficiency, high reservoir damage, single function, and poor environmental adaptability, providing a novel fracturing fluid additive with superior performance for the efficient development of unconventional oil and gas resources.

The invention discloses a kelp mucus drag reducer and a preparation method thereof, and belongs to the field of underwater drag reduction. The kelp mucus drag reducer comprises kelp mucus and sodium bicarbonate. The preparation method comprises the following steps: pretreating kelp serving as a raw material to obtain kelp mucus; adding sodium bicarbonate powder into the pretreated kelp mucus, adjusting the pH to make a weakly alkaline environment, and filtering by adopting a filter screen to obtain kelp mucus mother liquor; calculating the concentration of the kelp mucus mother liquor; according to the measured concentration of the kelp mucus mother liquor, the kelp mucus mother liquor is dried and concentrated or diluted with water, and the kelp mucus drag reducers with different concentrations are prepared through sufficient stirring. The problems that an existing drag reducer preparation method is tedious and unfriendly to the environment are solved.

The application discloses a polymer drag-reducing agent injection type hydrofoil, and belongs to the technical field of polymer drag-reducing agents of underwater vehicles. The application solves the problem that there is no drag-reducing agent injection structure capable of stably outputting polymer drag-reducing agents and capable of adhering to the surface of a drag-reducing part of an underwater vehicle. One end of a steady flow cavity is communicated with a solution storage box in the underwater vehicle through a discharge channel, a cover plate is parallel and slidingly inserted on a main body of the hydrofoil, the lower surface of the cover plate is adhered to the upper surfaces of a plurality of fairing plates, and the outer surface of one end of the cover plate and the inner wall surface of one end of the steady flow cavity form an injection channel. The steady flow cavity has a steady flow effect on the solution, so that the stable output of the polymer solution is realized; the flow state of the polymer solution is adjusted through the fairing plates, so that the polymer solution flows stably; the polymer solution flows out to the surface of the hydrofoil through the injection channel, the frictional resistance generated during sailing is reduced, and the sailing performance of the underwater vehicle is improved.

The invention discloses a preparation method of a self-degradation fracturing drag reducer, and relates to the technical field of drag reducer preparation.The self-degradation fracturing drag reducer is prepared by mixing acrylamide, acrylic acid, methyl methacrylate, a modified additive and a modified filler to react, a molecular chain segment of the drag reducer contains a cyclodextrin structure, and the molecular chain segment of the drag reducer contains a cyclodextrin structure; the drag reducer can be self-degraded, cyclodextrin has a hydrophilic outside and a hydrophobic inside cavity ring structure, and can interact with hydrophobic groups in drag reducer polymer molecules through a host-guest inclusion effect, so that hydrophobic aggregation is destroyed, and drag reducer chains are easier to stretch and dissolve in water; meanwhile, the thermal motion of a polymer molecular chain can be limited, the drag reducer is kept stable in a high-temperature stratum, the flowing resistance of fracturing fluid in pipelines and cracks can be effectively reduced due to the self-lubricating characteristic of the modified filler, and the anti-shearing effect of the drag reducer can be improved due to the cooperation of the modified filler and a cyclodextrin structure on the molecular chain.

The invention belongs to the field of well cementation operation in petroleum engineering, and discloses a high-performance low-density cement paste system suitable for a wide temperature range and application. The cement paste system comprises the following components in parts by weight: 100 parts of oil well G-grade cement, 20-28 parts of modified hollow glass beads, 3-15 parts of a hydration process regulator, 5-10 parts of a crystal form transition inhibitor, 1-2 parts of a drag reducer, 3-6 parts of a fluid loss agent, 3-4 parts of a retarder, 0.2-1.0 part of a defoaming agent and 44-54 parts of water, according to the high-performance low-density cement paste system suitable for the wide temperature range condition, the cement paste fluidity is good, the thickening time is adjustable, through matched use of the retarder and the fluid loss agent, the problem that the strength development of the top cement paste is slow under the wide temperature range condition is solved, the long-term strength development is stable, the internal microstructure of set cement is compact, and the performance is good. And engineering requirements can be met, and well cementation engineering safety and engineering quality are effectively guaranteed.

The invention relates to the technical field of oil and gas field well drilling and cementing, in particular to an anti-channeling tough cement paste system and a preparation method and application thereof, and aims at effectively relieving the problem that the sealing integrity of a cement sheath is damaged in the large-volume fracturing production process. According to the anti-channeling tough cement paste provided by the invention, the flexural strength is improved, meanwhile, the rapid decline of the compressive strength can be slowed down, and relatively high compressive strength is reserved. The invention provides an anti-channeling tough cement paste system which comprises the following components in parts by weight: 100 parts of oil well cement; 1-4 parts of a toughening agent; 0.7 to 2.5 parts of a fluid loss agent; 0 to 0.5 part of a drag reducer; 0-35 parts of a stabilizer; 1-4 parts of a suspending agent; 0 to 2.5 parts of a retarder; 0.1 to 0.3 part of a defoaming agent; and 42 to 54 parts of water.

The invention relates to a natural gas drag reduction evaluation device under the synergistic effect of a pipe wall interface layer and turbulent flow drag reduction. The device comprises a nitrogen purging system, a natural gas turbulence circulating system, a drag reducer quantitative injection system, a PIV imaging and testing system and a drag reducer filtering and recycling system. The nitrogen purging system is used for cleaning an experimental loop, the natural gas turbulence circulating system is used for simulating turbulence states under different working conditions, and the duplex organic glass transparent test pipe section group can test flow characteristics under different pipe diameters and inner wall conditions; the drag reducer quantitative injection system adopts a plunger pump and an atomization device to ensure that the drag reducer is uniformly dispersed; the PIV imaging and testing system is used for accurately capturing a turbulent flow microstructure. Through macroscopic flow and microscopic turbulence structure observation, the drag reduction performance under the synergistic effect of the inner coating and the drag reducer and the influence of factors such as the pipe diameter, the position, the concentration and the variety of the drag reducer on the drag reduction effect are evaluated, and experimental data and a theoretical basis can be provided for engineering application of the natural gas drag reduction technology.

The invention discloses a shear-resistant, high-drag-reducing, high-viscosity slickwater drag reducing agent and a preparation method therefor. The drag reducing agent is polymerized from acrylamide, sodium acrylate, a sulfonate ion-containing hydrophobic monomer, a hydrophobic unit microblock regulator, a molecular weight modifier, and a composite initiator. Through the special sulfonate ion-containing hydrophobic monomer, the hydrophobic unit microblock regulator matched with a hydrophobic monomer and the control of a polymer molecular weight, the solubility and viscosity-increasing performances of the polymer can be significantly improved, the shear-resistant and degradation-resistant performance of the drag reducing agent is improved, with excellent sand carrying performance and drag reducing performance, and the shortcomings of existing slickwater drag reducing agents such as weak shear resistance, rapid decline in drag reduction rate and poor sand carrying performance are overcome, thereby meeting the special requirements of deep / ultra-deep oil and gas reservoir fracturing on fracturing fluid rheology.

The application relates to the field of turbulent flow control in fluid mechanics and discloses a natural gas drag-reducing agent atomization injection indoor circulation system. The system is composed of a natural gas drag-reducing agent atomization device and an indoor circulation pipeline; the natural gas drag-reducing agent atomization device comprises a shell, a conical jet cylinder and a gas-liquid mixing cavity; a conical jet cylinder and a nozzle are arranged in the shell; the nozzle can be automatically adjusted within an angle range of 20-80 degrees according to the natural gas conveying flow; a blade support plate cuts the mixed drag-reducing agent to atomize the drag-reducing agent again; the particle size of the atomized drag-reducing agent ranges from 20 to 40 microns; square magnet blocks are evenly arranged on the outer wall of the indoor circulation pipeline; the number of the square magnet blocks is 114; the length of each square magnet block is 200 mm, the width is 80 mm, and the thickness is 50 mm. The application utilizes the comprehensive effect of jet flow, cutting and electromagnetic field to enhance the atomization and adhesion effect of the drag-reducing agent; the drag-reducing effect of the drag-reducing agent atomization injection is evaluated based on control variables; and the result can be applied to the drag-reducing conveying of a natural gas long-distance pipeline.