77results about How to "Reduce water injection pressure" patented technology

The invention relates to a nano material-based water-based oil field injection agent and a preparation method thereof. The injection agent consists of 20 to 60 weight percent of diesel oil, 30 to 70 weight percent of surfactant, 1 to 10 weight percent of nano material and 1 to 20 weight percent of auxiliary agent, wherein the nano material is one or more of nano silicon dioxide, nano titanium oxide, nano magnesium oxide and nano aluminum oxide after surface modification. The preparation method thereof comprises the following steps that: firstly, weighing the diesel oil in proportion; secondly, adding the nano material in the diesel oil; thirdly, emulsifying and dispersing the mixture in an emulsifying machine; fourthly, adding the surfactant and the auxiliary agent into the emulsified and dispersed mixture; and finally, mechanically stirring to disperse the mixture at room temperature or in a water bath to obtain stock solution of the nano water-based injection agent. The injection agent can be mixed with water at any proportion to obtain homogeneous emulsified dispersion. After the emulsified dispersion is injected in the oil field through a specific process, the water injection pressure can be obviously reduced, the amount of water injection can be increased and the oil production efficiency can be improved so as to achieve the purpose of energy conservation and injection increase.

A method for removing sulfate radical from injected water in oil field for anti-scaling is applied in anti-scaling of oil fields and oil-water wells. The method is characterized by firstly pumping injected water into a coarse filtration system by a high-pressure pump for carrying out the coarse filtration treatment and then into a fine filtration system for treatment; and further pumping the injected water after the two-stage filtration by the coarse filtration system and the fine filtration system into a nanofiltration system for treatment. The injected water after the treatment is divided into clear water and condensed water. The clear water is directly re-injected to the underground target layer position. A ternary complex scale cleaning agent is added before the injected water enters the fine filtration system. The method has the effects that a nanofiltration film is adopted to remove sulfate ions in the injected water, thereby solving barium and strontium scales generated by incompatibility of the injected water and formation water, and the anti-scaling rate can be more than 80 percent; the ternary complex scale cleaning agent is added in the injected water before the injected water enters the fine filtration system, thereby leading the clear water after the treatment to be capable of reducing the formation scales and further reducing the scales of the nanofiltration film of the nanofiltration system.

The invention provides an active anti-swelling and swelling-shrinkage agent and a preparation method and application thereof. Water is added to a closed container, cation modified starch, dimethyl diallyl ammonium chloride and epoxy chloropropane are sequentially added, a reaction is conducted for 3 h under the 100-DEG-C constant-temperature condition, after the container is cooled to 40 DEG C, ethidene diamine, potassium peroxodisulfate and urea are added, the mixture is stirred to be uniform, and raw materials are obtained; the raw materials are taken, potassium chloride or ammonium chloride is added, 1-2 parts of fluorinated surfactant is added, the balance is water, the mixture is stirred to be uniform, and a product is obtained; the product is diluted into a solution with the mass concentration of 2-5%, and the solution is injected into an oil layer to be used. The active anti-swelling and swelling-shrinkage agent has an obvious anti-swelling effect, water injection efficiency is improved, and the water injection amount meets injection allocation requirements.

The present invention relates to a nano liquid for decompression and augmented injection of tight oil water-flooding, and a preparation method and application thereof. The nano liquid for decompression and augmented injection is composed of 0.1-1% of hydrophobic nano-silica, 0.3-3% of a dispersant, 0.2-1% of a dispersing aid and the balance of water. The hydrophobic nano-silica has particle size between 12-22 nm, and median diameter between 16-18 nm; and the hydrophobic nano-silica is prepared from fumed nano silica and an organic silicon compound by a wet modification method. The dispersant is octylphenyl polyoxyethylene ether, polyethylene glycol 400, polyethylene glycol 600 or glycerin. The dispersing aid is NaOH, Na2SiO3 or n-butanol. The nano liquid for decompression and augmented injection employs water base dispersion and has the advantages of environment-friendliness, simple preparation and good stability. Under the action of stratum water salt ions, the hydrophobic nano-silica is adsorbed on the surface of the rock, so that wetting conversion generates on the rock surface to produce hydrophobic slip effect and reduce flow resistance and injection pressure.

The invention belongs to the technical field of oil and gas fieldchemistry and discloses a decompression and augmented injection agent for a water injection well of a low-permeability reservoir. The decompression and augmented injection agent comprises the following components by weight percent: 30%-35% of bisoctyl dimethyl ammonium chloride, 3%-7% of a fluorocarbon surfactant, 3%-5% of a non-ionic surface active agent, 5%-10% of ethylene diamine tetra (methylene phosphonic acid) sodium, 2%-5% of dimethyl ketoxime and 38-57% of water. The invention also provides a preparation method for the decompression and augmented injection agent. The decompression and augmented injection agent takes water solution as a transmitting medium and forms an ultrathin molecular film by depositing on the rock surface; the decompression and augmented injection agent has a function of changing the core wettability and clay anti-swelling property; the decompression and augmented injection agent also has multiple effects of corrosion inhibition, scale inhibition, sterilization, and the like, can effectively prevent the influence on the formation porosity caused by injected water corrosion products, scaling, bacteria, and the like, and can greatly promote the water injection effect of the water injection well of the low permeability reservoir. Being as a novel decompression and augmented injection agent with excellent decompression and augmented injection effects, the decompression and augmented injection agent has wide market prospect.

The invention relates to a method for sterilizing oil field sewage by cooperating electrochemical oxidation with an ultraviolet and ultrasonic technology and belongs to treatment of the oil field sewage. The method comprises the following steps of: (1) electrolyzing, wherein available chlorine can be generated from the sewage, the current density is in the range of 5 to 3,000A / m2 and the concentration of the available chlorine is in the range of 0.1 to 40mg / L; (2) carrying out ultrasonic-ultraviolet compound treatment and degerming by cooperating the available chlorine with the ultrasonic cavatition and ultraviolet irradiation, wherein the frequency of ultrasonic waves is in the range of 20 to 500KHz and the wavelength of ultraviolet rays is in the range of 100 to 400nm; and (3) washing aquartz socket tube by cooperating chlorine generated by electrolysis with the chemical cleaning effect of the ultrasonic waves. The method is mainly characterized in that (1) the available chlorine is generated by electrochemical oxidation to carry out primary sterilization; (2) the residual chlorine is cooperated with the ultrasonic cavatition and the ultraviolet irradiation to completely sterilize; (3) after treatment, the residual chlorine in a water body is used to continuously sterlize; and (4) the chlorine generated by electrolysis is cooperated with the ultrasonic cavatition to preventscale from depositing on the surface of the quartz socket tube of an ultraviolet lamp.

The invention discloses a pre-treating agent for a water injection well of a low-permeability reservoir and a manufacturing method of the pre-treating agent, and belongs to the technical field of water injection well development of an oil field. The pre-treating agent comprises the following components, by mass percentage, 0.3-0.8% of a surfactant, 1-2% of ammonium chloride, 2-5% of ethanol, 2-5% of a micro-molecular cationic polymer, 1-5% of ethylene glycol monobutyl ether, 10-15% of hydrochloric acid, 1-3% of hydrofluoric acid, 2-4% of a corrosion inhibitor, and 1-2% of an iron-ion stabilizing agent, with the balance being water. The surfactant comprises, by mass percentage, 75-90% of a fluorocarbon surfactant, with the balance being betaine and / or fatty acid diethanol amide. Components in the pre-treating agent match each other well and can be used at the same time. Through adoption of the pre-treating agent, multiple slugs are effectively form one slug through pre-treatment before casting of the water injection well, and the oil-water interfacial tension is reduced to or below 3*10<-4> mN / m. The water injection pressure is reduced, and the effect of preventing swelling and relieving solid blocking is achieved. Pressure reduction and injection increase are effectively achieved, and the construction efficiency is obviously increased.

The invention relates to the field of chemical water production in power plants, and discloses a method for regenerating a desalting mixed bed. In the method, the liquid level in a mixed bed tank reduces to the top of a resin layer before the resin layer is subjected to hydrodynamic backwashing layering, and compressed air is introduced into the mixed bed tank to perform air washing, so the resinis effectively loosened, the water injection pressure of the subsequent backwashing step is reduced, the backwashing layering effect is enhanced, the backwashing layering time is significantly shortened, and the consumption of backwashing water in the resin backwashing layering process is reduced. After the resin is backwashed with water, the control of the concentrations and the flow amounts of aregeneration alkali solution and a regeneration alkali solution can significantly reduce the consumptions of the regeneration alkali solution and the regeneration alkali solution in the resin regenerating process and greatly shortens the regeneration time of the desalting mixed bed. The water production volume of the desalting mixed bed in a single period is high, and the outlet water of the regenerated desalting mixed bed has excellent quality.

The invention relates to an oilfield water-injection injection augmentation agent and in particular relates to a nano-solution for decompression and injection augmentation of ultra-low permeability oil reservoir water-flooding development and a preparation method of the nano-solution. The nano-solution for the decompression and injection augmentation is prepared from double-radical modified nano silicon dioxide grains and a NaOH water solution, wherein the double-radical modified nano silicon dioxide grains are commonly modified by alkyl and alkyl acid. The nano-solution for the decompression and injection augmentation is simple in preparation, uniform in dispersion and good in stability. After the nano-solution is injected into a stratum, the double-radical modified nano silicon dioxide grains are attached on surfaces of reservoir rocks; hydration films on the surfaces of the rocks are stripped to form nano adsorption layers; with the pH (Potential of Hydrogen) in a stratum water environment becomes neutral from alkaline, the surfaces of the rocks become wet, so that a lyophobic slippage effect is generated and the aims of reducing water flow resistance and injection pressure are realized.

The invention discloses a multi-hydrogen acid construction process suitable for modification of a sandstone reservoir. The multi-hydrogen acid construction process suitable for modification of the sandstone reservoir successively comprises the following steps: step one, carrying out replacing on 10-20 m<3> of a pre-treating solution or a mutual solvent under the conditions that the discharge capacity is 0.1-0.5 m<3> / min, and the pump pressure is 1-34 MPa; step two, carrying out extrusion on 10-20 m<3> of pad-acid under the conditions that the discharge capacity is 0.1-0.5 m<3> / min, and the pump pressure is 1-34 MPa; step three, carrying out extrusion on 20-50 m<3> of main body acid under the conditions that the discharge capacity is 0.1-0.5 m<3> / min, and the pump pressure is 1-34 MPa; andstep four, carrying out extrusion on 5-20 m<3> of water well displacing liquid or oil well displacing liquid under the conditions that the discharge capacity is 0.2-1 m<3> / min and the pump pressure is1-34 MPa to finish acidification modification on the sandstone reservoir under a water well or an oil well. The multi-hydrogen acid construction process suitable for modification of the sandstone reservoir is used for carrying out augmented injection on an acidized horizon, blockage of a pore throat channel of a stratum is relieved, the water injection amount is increased, water injection pressure is reduced, the oil and gas recovery efficiency is improved, and compared with a conventional acidifying process, the multi-hydrogen acid construction process suitable for modification of the sandstone reservoir is more environmentally friendly and safer, and provides a safe operation condition for human beings, equipment and environments.

The invention discloses a plug removal agent for an oil-water well of a tight oil reservoir. The plug removal agent is prepared from the following components in percentage by mass: 8.0 to 15.0 percent of organic sulfonic acid, 5.0 to 8.0 percent of organic carboxylic acid, 0.5 to 1.5 percent of hydrofluoric acid, 3.0 to 12.0 percent of fluoroboric acid, 0.5 to 1.5 percent of mutual solvent, 0.5 to 1.0 percent of wetting reversion agent, 5.0 to 10.0 percent of chelating agent, 0.5 to 1.5 percent of clay stabilizer, and the balance of water. According to the plug removal agent disclosed by the invention, the problem that the tight oil reservoir is easily plugged by primary particles and secondary particles due to high mud content, poor reservoir physical property and small pore throat radius is solved, the reservoir permeability is recovered and improved to the maximum extent, the percolation capacity of a stratum with actual control radius of the oil-water well is improved, and the aims of improving the production capacity of the oil-water well, and realizing enhanced production of an oil well and intensified injection of a water well are achieved.

The invention provides an oil displacing microemulsified acid system for acidizing plugging removal and a preparation method of the system. The oil displacing microemulsified acid system is prepared from the following components in percentage by weight: 10-35% of diesel fuel, 40-75% of acid fluid, 10-30% of alkylsulfobetaine, 1-15% of fatty amine polyoxyethylene ether phosphate, and the balance of 10% hydrochloric acid. The preparation method of the system comprises the following steps: weighing the raw materials by weight; firstly, putting acid fluid into a vessel, heating and stirring in water bath at 60 DEG C, adding alkylsulfobetaine and fatty amine polyoxyethylene ether phosphate for dissolving thoroughly, and then adding 10% ydrochloric acid; and next, adding the diesel oil and stirring for 0.5 hour, thereby obtaining the finished product. The oil displacing microemulsified acid system is a thermodynamic stable system, has excellent dissolving property to inorganic matters and organic matters, and excellent oil displacing property, and can be widely applied to the measures of a water injection well and an oil well conversion well.

The invention discloses a water injection well decompression and injection-augmentation agent containing biosurfactant, and relates to the technical field of oil exploitation auxiliaries. The water injection well decompression and injection-augmentation agent containing the biosurfactant is prepared from, by weight, 62-71 parts of lipopeptide biosurfactant, 22-31 parts of ampholytic surfactant, 3-5 parts of solubilizing assistant, 3-5 parts of clay stabilizer and 2-4 parts of scale inhibitor. According to the water injection well decompression and injection-augmentation agent containing the biosurfactant, wettability can be changed, oil-water interfacial tension is lowered to 10<-3> mN / m, in this way, starting of residual oil is facilitated, the phenomenon that the decompression and injection-augmentation agent causes emulsification to crude oil, so that water injection pressure rises can be avoided, the water injection well water injection pressure is effectively lowered, and the under injection well water injection capacity is improved; meanwhile, clay swelling can be prevented, and damage of carbonate precipitation such as calcium carbonate to stratum can be inhibited; the lipopeptide biosurfactant is adopted as the biosurfactant, and the water injection well decompression and injection-augmentation agent has the advantages of being environmentally friendly, low in dosage, good in water solubility, low in price and the like.

The invention relates to an injection friction-reducing agent for improving the injection capacity of a water injection well of an extra-low permeability reservoir of an oilfield, and application thereof. The injection friction-reducing agent comprises the following compositions by weight percent: (a) 0.8 to 8 weight percent of amine compounds; (b) 1.2 to 12 weight percent of composite carboxylate; (c) 1.7 to 17 weight percent of composite quaternary ammonium salt cationic surfactant; (d) 0.4 to 4 weight percent of combined surfactant containing alkyl polyhydric alcohol ether; and the balance of water. The invention is used for the oilfield injection friction-reducing agent, wherein the dosage of a single well is between 8 and 10 tons; the working concentration is between 2,000 and 5,000 mg / L; the injection pressure is reduced to be between 2 and 5 MPa; the effective period of stable injection capacity is more than 12 months; and the interfacial tension of the oilfield injection friction-reducing agent and crude oil under the condition of stratum can reach 10 mN / m magnitude order.

A decompression and injection-stimulation gemini surfactant system for oil fields and a preparing method thereof are provided. The system is a mixed system consisting of a heterogemini amphoteric surfactant as a main component, a nonionic amphoteric gemini surfactant as an auxiliary agent, an anionic surfactant and water. Compared with products in the prior art, the system has a wide spectrum anda wide adaption range; the system has a wide application concentration range, and the interfacial tension of the system can still be 10<-3> mN / m with a low application concentration (0.1%); the systemhas good wettability, high permeability, high oil washing efficiency, and good salt resistance, and is free of precipitate and turbid phenomena in an aqueous solution having a salt content of 100,000ppm (with the content of calcium and magnesium ions being 5,000 ppm); the system is resistant to high temperature and wide in application temperature range; the system is neutral, free of organochlorine and free of alkali and does not cause harm to stratums; and the system can greatly reduce water injection pressure for a water injection well and increase the water injection efficiency.

The invention provides a clay anti-swelling stabilizer which is prepared from the following raw materials by weight percent: 65-80% of BH-2018 surfactant, 1-15% of sodium alginate, 1-10% of glycol, 5-15% of KCl and 10-28% of glycerol. The clay anti-swelling stabilizer is wide in raw material source, less in production consumed energy, low in cost, high in anti-swelling efficiency and comprehensive in mechanism, and has the effect of improving recovery efficiency. When 1% clay anti-swelling stabilizer is used for injection, the anti-swelling property can achieve more than 85%. The invention also provides a preparation method of the novel clay anti-swelling stabilizer.

The invention relates to pseudomonas aeruginosa YM4 CGMCC No.5243, and a culture method and application thereof. The culture method for the pseudomonas aeruginosa YM4 comprises the following steps: inoculating the pseudomonas aeruginosa YM4 into a fermentation culture medium; and cultivating in a shaking table at the temperature of 35 or 55 DEG C and at the rotating speed of 120 or 80 rpm, wherein the formula of the fermentation culture medium comprises glucose, peptone, corn paste, sodium nitrate, disodium hydrogen phosphate, potassium dihydrogen phosphate, magnesium sulfate and calcium chloride, and the pH value of the fermentation culture medium is 6.5 to 7.4. A biological surfactant generated by the pseudomonas aeruginosa YM4 can reduce oil water interface tension in the oil field; and after the action, the rheological property of the crude oil is obviously improved, viscosity is reduced, water injection pressure can be effectively reduced, water injection efficiency and recovery ratio of the crude oil can be improved; and large application prospect is achieved in the oil displacement process of the oil field.

The present invention provides a scale remover used for long-acting pressure decrease and injection increase of a water injection well, and the scale remover comprises the following components: 10-12 parts of Tween 80; 25-30 parts of 2-Phosphonobutane-1,2,4-tricarboxylic acid; 5-8 parts of dodecylbenzene sulfonic acid; 3-6 parts of an organosilicon surfactant; 2-5 parts of ethylene glycol butyl ether; 15-18 parts of n-butanol; 13-15 parts of polyamino polyether methylene phosphate and 12-14 parts of water. The scale remover has good anti swelling and swelling shrinkage capability and low surface and interface tension, and the scale remover reduces deformation work when liquid droplets pass through a narrow hole neck, reduces capillary resistance, greatly reduces the deformation work when the liquid droplets in a pore medium are pulled to spread on the surface of a rock so as to increase the moving speed of the liquid droplets in formation pores. After being injected into formation, the scale remover reduces the interfacial tension, meanwhile can restore an original water channel, reduce water injection pressure and improve water injection amount by dissolution of calcium carbonate, calcium sulfate and other precipitates near a wellbore area so as to ensure that the original water injection system is normal.

The invention provides an oilfield water injection device. The device comprises a dosing pot, a dosing pump, and a water injection pump. The dosing pot comprises a dosing inlet and an outlet. The outlet of the dosing pot is communicated with the inlet of the dosing pump. The dosing pump is a diaphragm metering pump. The inlet of the water injection pump is communicated with the water outlet pipe of a water injection station. The outlet of the water injection pump is connected with a first outlet of the dosing pump and is communicated with the water injection pipe of a water injection well. The dosing pump also comprises a second outlet. The second outlet is communicated with the inlet of the dosing pot through a reflux pipeline. The oilfield water injection device can improve water injection pressure to achieve an objective of water injection well stimulation, and realizes to fill medicament on line to dredge reservoir blocking, and improves water absorption capacity of a water injection well. Correspondingly, after a stratum is dredged, water injection pressure is reduced, so just short-term high-pressure water injection is needed, and damages of a water injection pipeline and a stratum caused by long-term high-pressure water injection.

The invention belongs to the technical field of waterflooding extraction of oilfields, and particularly provides a continuous injecting and acidizing unit for a water injection well. The continuous injecting and acidizing unit for the water injection well consists of an acid liquor storage tank (1), a hydraulic double-diaphragm metering pump (2), a control system (3), an acid liquor pipeline system (4), an online monitoring system (5) and a truck moving system, wherein the acid liquor storage tank (1) is connected with the hydraulic double-diaphragm metering pump (2); an outlet of the hydraulic double-diaphragm metering pump (2) is connected with the acid liquor pipeline system (4); the control system (3) is connected with the hydraulic double-diaphragm metering pump (2); the online monitoring system (5) is connected with the acid liquor pipeline system (4); and a shared steel base of the acid liquor storage tank (1), the hydraulic double-diaphragm metering pump (2) and the control system (3) is connected with a chassis of the truck moving system. Efficient, quick and large-scale plug removal of the water injection well is implemented, water injection pressure is reduced, and water injection amount is increased.

The invention discloses a method for reducing pressure and increasing injection through a gemini surfactant. The method comprises orderly injecting hydrochloric acid containing an additive, mud acid containing an additive and a gemini surfactant solution into the middle of an oil layer, then injecting water into the oil layer to eject the agents to the stratum after the gemini surfactant is injected, and after well completion, injecting water, wherein the mud acid use amount of each meter of the oil layer is 0.5-2 m<3>, the hydrochloric acid use amount of each meter of the oil layer is 0.8-1.2times the mud acid use amount of each meter of the oil layer, the gemini surfactant use amount of each meter of the oil layer is 4-8 m<3>, the gemini surfactant solution is an ethyldidodecylammoniumphosphate solution and has a concentration of 5.0% to 7.5%. The gemini surfactant realizes pressure reduction and injection increasing of a low-permeability reservoir water injection well and has an effective period longer than the conventional acidification measure. The method can utilizes a water injection pipe column for construction, is free of acid solution returning, orderly injects agents,has simple processes, is easy to operate, has a short construction period and has large economic effects.

The invention discloses an anti-swelling shrinking agent which comprises, by weight, 15.7-64.68 parts of tertiary amine, 6-13.3 parts of epoxy chloropropane, 5-13.5 parts of hydrochloric acid and 12-32 parts of organic solvents. The tertiary amine, the epoxy chloropropane and the hydrochloric acid react in the organic solvents to generate long-chain quaternary ammonium salt with good surface activity. By electrostatic interaction, the long-chain quaternary ammonium salt with positive charge is easily adsorbed on the surfaces of clay particles with negative charge, crystal layer repulsion of the clay particles is reduced, the clay particles can be separated from water molecules, and continued hydrous swelling of the clay particles is inhibited. Surplus positive charge continues to be adsorbed on the surfaces of the clay particles, double electric layers are compressed by electrostatic repulsion, the distance between clay layers is shortened, and the anti-swelling shrinking agent has shrinking effects. The anti-swelling shrinking agent has anti-swelling and shrinking functions and further has surface activity. The invention further provides a preparation method of the anti-swelling shrinking agent.

The invention provides an ultra-low permeability reservoir decompression and augmented injection system and a preparation method. The system is prepared from the following components in percentage byweight: 0.10-0.20% of a surfactant, 0.20-0.30% of an anti-swelling agent, 0.05-0.10% of an anti-scaling agent and the balance of formation water. The decompression and augmented injection system has good compatibility with formation water, and is suitable for formation water with different mineralization degrees; the oil-water interfacial tension can be effectively reduced, and the wettability ischanged; clay expansion can be obviously inhibited; scale formation can be effectively inhibited, and the scale inhibition rate is high; and the system can be stored and used for a long term.

The invention relates to an energy-releasing composite preparation and a preparation method thereof, belonging to perforating slurry for oilfield exploitation. The energy-releasing composite preparation is prepared by mixing the following components in parts by weight: 41-53 parts of an adhesive, 40-60 parts of a combustion agent, 5-15 parts of a functional additive, 8-10 parts of an accelerant, 1-3 parts of a curing agent and 5-7 parts of a crack proppant. A combination of the prepared slurry and perforating bullets can reduce a perforation skin coefficient by 10%, and plays a good role in reducing water injection pressure and increasing output in domestic low-permeability oil and gas reservoirs such as Yanchang Oilfield and Changqing Oilfield. The average penetration depth of a perforator assembled with the slurry is 825 mm while the average penetration depth of a perforator without the slurry is 785 mm, so the penetration depth is improved by 5.1% and an aperture is increased by 6.1%. The produced slurry is made of inert materials, has no risk in production and assembly, is safe and reliable, and belongs to energy-releasing products. The produced slurry meets technical requirements, has an explosion heat test value of no less than 2600 kJ / kg, can resist a temperature of 180 DEG C for 48h, and is free of rheological phenomenon and spontaneous combustion.

The invention relates to a single-well parallel crack water injection and oil extraction method of an offshore low-permeability reservoir. A single well at least consists of a main well hole, and two oil extraction branches, a water injection branch and a set of parallel manual cracks positioned in a reservoir, wherein the oil extraction branches and the water injection branch are horizontal wells, and extend along a maximum main stress direction of a stratum; the water injection branch is positioned between the two oil extraction branches; the water injection branch and the oil extraction branches are subjected to the staged fracturing operation to generate the manual cracks parallel to shafts; the water injection operation is performed by the water injection branch positioned between the two oil extraction branches; and injected water diffuses along crack surfaces and enters the stratum after entering the manual cracks. The method has prominent effects on increment of the controlled reserve, reduction of the cost and improvement of the development effect in the development of the offshore low-permeability reservoir.

The invention relates to a slow blocking remover for a deep part of an oil and water well. The slow blocking remover comprises following components by weight: 1.5-2.0% of sodium dodecyl benzene sulfonate, 5.5-7.5% of ethylene diamine tetra (methylene phosphonic acid) sodium, 20.0-25.5% of diethylenetriam inepentaacetate, 15.5-17.5% of methanesulfonic acid, 0.5-1% of sodium acetate, and the balance water. The blocking remover not only can remove scaling and blocking of near-wellbore, but also can remove scaling and blocking of the deep part of stratum, and finally reaches purposes of yield increase of the oil well and injection increase of a water injection well.

The invention discloses a nanometer poly-silicon emulsion. The nanometer poly-silicon emulsion is prepared from 40-50 parts of hydrophobic nanosilicon dioxide, 10-15 parts of a sodium hydroxide aqueous solution, 10-15 parts of fatty alcohol-polyoxyethylene ether AEO-9, 8-10 parts of sodium alpha-olefin sulfonate and 5-10 parts of cocoalkanoylamido propyl betaine in 300-500 parts of deionized water. According to the formula proportion, part of the deionized water, fatty alcohol-polyoxyethylene ether AEO-9, sodium alpha-olefin sulfonate and cocoalkanoylamido propyl betaine are taken and uniformly mixed to be heated and stirred until a solution is clarified, cooling is conducted, the hydrophobic nanosilicon dioxide and the sodium hydroxide aqueous solution are added, the PH value is controlled to 8-10, the remaining part of deionized water is added, heating is conducted until the materials are boiled, turbid and then clarified, and then the nanometer poly-silicon emulsion is obtained. According to the nanometer poly-silicon emulsion, secondary pollution can be reduced, and the problems are effectively solved that in the later development period, the water injection pressure is high, the water injection amount does not meet the injection allocation requirement, and the injection increase validity period is short.

The invention provides an environment-friendly pressure-reducing injection-increasing multi-twin active agent and a preparation method thereof, wherein the environment-friendly pressure-reducing injection-increasing multi-twin active agent comprises, by mass, 0.01-0.5% of a polyoxyethylene copolymer resin, 2-45% of dimethyl diallyl ammonium chloride, 5-20% of an organic guanidine compound, 4-16% of a quaternary ammonium salt, 0.1-0.6% of a pH regulator, 0.1-0.6% of a cloud point regulator, and the balance of water. According to the invention, with the environment-friendly pressure-reducing injection-increasing multi-twin active agent, the hydrated expansive clay in stratum becomes insensitive when contacting the injected water, or the reservoir with low permeability expands reversely whilethe resistance of the injected water is substantially reduced, so that the pressure-reducing injection-increasing and plugging release of oil and gas field water injection wells is achieved.

The invention discloses a pre-treating agent for a water injection well of a low-permeability reservoir and a manufacturing method of the pre-treating agent, and belongs to the technical field of water injection well development of an oil field. The pre-treating agent comprises the following components, by mass percentage, 0.3-0.8% of a surfactant, 1-2% of ammonium chloride, 2-5% of ethanol, 2-5% of a micro-molecular cationic polymer, 1-5% of ethylene glycol monobutyl ether, 10-15% of hydrochloric acid, 1-3% of hydrofluoric acid, 2-4% of a corrosion inhibitor, and 1-2% of an iron-ion stabilizing agent, with the balance being water. The surfactant comprises, by mass percentage, 75-90% of a fluorocarbon surfactant, with the balance being betaine and / or fatty acid diethanol amide. Components in the pre-treating agent match each other well and can be used at the same time. Through adoption of the pre-treating agent, multiple slugs are effectively form one slug through pre-treatment before casting of the water injection well, and the oil-water interfacial tension is reduced to or below 3*10<-4> mN / m. The water injection pressure is reduced, and the effect of preventing swelling and relieving solid blocking is achieved. Pressure reduction and injection increase are effectively achieved, and the construction efficiency is obviously increased.

The invention relates to a method for sterilizing oil field sewage by cooperating electrochemical oxidation with an ultraviolet and ultrasonic technology and belongs to treatment of the oil field sewage. The method comprises the following steps of: (1) electrolyzing, wherein available chlorine can be generated from the sewage, the current density is in the range of 5 to 3,000A / m2 and the concentration of the available chlorine is in the range of 0.1 to 40mg / L; (2) carrying out ultrasonic-ultraviolet compound treatment and degerming by cooperating the available chlorine with the ultrasonic cavatition and ultraviolet irradiation, wherein the frequency of ultrasonic waves is in the range of 20 to 500KHz and the wavelength of ultraviolet rays is in the range of 100 to 400nm; and (3) washing aquartz socket tube by cooperating chlorine generated by electrolysis with the chemical cleaning effect of the ultrasonic waves. The method is mainly characterized in that (1) the available chlorine is generated by electrochemical oxidation to carry out primary sterilization; (2) the residual chlorine is cooperated with the ultrasonic cavatition and the ultraviolet irradiation to completely sterilize; (3) after treatment, the residual chlorine in a water body is used to continuously sterlize; and (4) the chlorine generated by electrolysis is cooperated with the ultrasonic cavatition to preventscale from depositing on the surface of the quartz socket tube of an ultraviolet lamp.