832 results about "Oil displacement" patented technology

The invention discloses a synthesis method of amphiphilic quantum dots and application of the amphiphilic quantum dots in nano oil displacement, and belongs to the field of nano oil displacement. The synthesis method comprises the following steps: heating a mixture containing a carbon source and a nitrogen source in an air atmosphere for reaction, and centrifuging, filtering and drying a reaction product to obtain the amphiphilic quantum dots, the carbon source is selected from at least one of glucose, mannose, citric acid, lignin, chitosan and starch; the nitrogen source is selected from at least one of alkylamine, and the carbon chain length of the alkylamine is C6 to C12. The synthesis method is simple, heating of a high-pressure reaction kettle is not needed, the technological process is simple, and the method is suitable for large-scale industrial production; the series of amphiphilic carbon quantum dots show better solubility and higher absolute fluorescence quantum yield in water and various organic solvents.

The invention relates to the technical field of oil-displacing agents, and particularly discloses a targeted nano oil-displacing agent and a preparation method thereof. A preparation method of a targeted nano oil displacement agent comprises the following steps: S1, dispersing 10-30 parts by mass of silanized inorganic nanoparticles in an alcoholic solution, adding 5-12 parts by mass of a functional monomer, 8-20 parts by mass of a hydrophilic monomer and 5-15 parts by mass of a hydrophobic monomer in an inert atmosphere, uniformly mixing, heating to 75-85 DEG C, adding an initiator, carrying out a constant temperature reaction for 4-6 h, and cooling to obtain a pre-grafted nanoparticle dispersion liquid; s2, mixing the pre-grafted nanoparticle dispersion liquid with a composite surfactant, adjusting the pH value to 6.5-7.5, and mixing at 30-40 DEG C for 22-26 hours to obtain the targeted nano oil displacement agent, the targeting type nano oil displacement agent prepared by the invention can still keep excellent dispersion stability and ultralow interfacial tension under the condition of a high-salt oil reservoir, so that the oil displacement efficiency is remarkably improved.

The invention relates to the field of oil and gas exploration and development displacement testing, provides a preparation and experiment method of a visual large-size planar heterogeneous core, and provides a large-size planar heterogeneous model with a specific structure, and the preparation method comprises the steps of raw material preparation, pressure forming, temperature control curing, cementing sealing, pouring, curing demolding and the like. The prepared rock core is used for simulating oil displacement experiments including water flooding, chemical flooding and subsequent water flooding so as to observe the sweep effect and the plugging effect of a chemical additive in the rock core, the performance of the chemical additive is evaluated in combination with actual production requirements of an oil reservoir, and theoretical guidance is provided for field practice.

The invention relates to the technical field of materials, in particular to preparation of an amphiphilic tungsten disulfide nano material and application of the amphiphilic tungsten disulfide nano material in preparation of an oil displacement agent. The oil-displacing agent prepared from the amphiphilic tungsten disulfide nano material can reduce the interfacial tension of an oil-water interface, and can be quickly adsorbed to the oil-water interface to layer oil and water; the surface wettability of the rock is changed, the lipophilicity of the rock is changed into weak hydrophilicity, and the pore throat cannot be blocked due to excessive hydrophilicity while the oil phase is stripped. The nano oil-displacing agent disclosed by the invention can still have an enough stable use effect after being frozen at a low temperature and then unfrozen.

The present invention belongs to the technical field of oil and gas exploration and development. Disclosed are a nuclear-magnetic-resonance-based method and system for characterizing the degree of miscibility of CO2 flooding. The method comprises: on the basis of a slim tube method, testing the minimum miscible pressure of crude oil of a target oil reservoir and CO2 (S101); on the basis of the minimum miscible pressure, conducting CO2 oil displacement experiments using cylindrical cores, collecting, in real time, two-dimensional weighted nuclear magnetic resonance images and multi-component T2 spectra of a fluid in the cores varying over time and space, synchronously collecting an outlet-end fluid, and conducting a chromatographic test to obtain chromatographic test data (S102); and on the basis of the two-dimensional weighted nuclear magnetic resonance images, the multi-component T2 spectra and the chromatographic test data, performing dynamically-changing qualitative and quantitative characterization on the degree of miscibility, so as to obtain qualitative and quantitative characterization results of the degree of miscibility of CO2 and the crude oil (S103).

The invention discloses a multi-site intelligent response type CO2 gas channeling prevention gel and a preparation method, and belongs to the field of chemical oil displacement, and the preparation method comprises the following steps: taking a carbon dioxide response type monomer, acrylamide and sodium acrylate as monomers, and adopting water-soluble free radical polymerization to prepare a CO2 response type copolymer; the CO2 response type copolymer, a cross-linking agent, a stabilizer, a retarder and formation water are prepared into a polymer cross-linking agent mixed solution, a cross-linking reaction is carried out under the conditions of formation temperature and mineralization degree, and the multi-site intelligent response type CO2 gas channeling prevention gel is obtained. The gel effectively solves the problems that a traditional anti-channeling agent is poor in injectivity in a low-permeability and ultra-low-permeability oil reservoir and cannot achieve deep channeling sealing, CO2 gas channeling fractured channels can be effectively blocked, the carbon dioxide oil displacement effect is remarkably improved, and key technical support is provided for large-scale application of carbon dioxide displacement.

The invention discloses a multi-alkyl aromatic alcohol extended block copolymer or oxysalt thereof as well as a synthesis method and application thereof. Molecules of the product contain polyalkyl, aryl, polyoxypropyl / ethyl and various ionic hydrophilic group structures, the product has excellent temperature resistance and salt tolerance and stable chemical properties, the adsorption loss in sandstone is extremely small, any alkaline agent does not need to be added, the crude oil recovery rate can be increased by 40% or above only through a single component at the concentration of 0.3 wt%, and the oil recovery rate can be increased by 30% or above. And the influence of performance degradation of the composite oil-displacing agent in an oil reservoir due to a chromatographic separation effect is avoided.

The application provides a low-grade oil reservoir water injection development effect evaluation method, comprising the following steps: S1, collecting core scale limit oil displacement efficiency data; S2, collecting well pattern controlled reserve degree data; S3, calculating sweep efficiency of the low-grade water drive oil reservoir; S4, correcting the sweep efficiency according to the changes of reservoir physical property parameters caused by near-well pollution and reservoir energy decline; and S5, calculating the reference recovery rate and evaluating the development effect. The application can effectively avoid collecting and arranging a large number of cumbersome production dynamic data, fully utilize the flow characteristics and dynamic physical property parameter evolution of the low-grade oil reservoir, accurately evaluate the development effect of the low-grade oil reservoir, and be beneficial to efficient development of the low-grade oil reservoir.

The invention belongs to the field of oil and gas exploitation, and particularly relates to a carbon dioxide-salt double-response polymer thickening agent and a preparation method thereof. The carbon dioxide-salt double-response polymer thickening agent provided by the invention is prepared from acrylamide, acrylic acid, alkyl polyether acrylate and amine carbon dioxide response monomers through solution polymerization; after corresponding monomers of amine carbon dioxide are protonated, polymer molecular chains are better stretched through electrostatic interaction, the viscosity of the fracturing fluid can be increased, complexation and crosslinking of oxyethyl, oxypropyl and calcium and magnesium ions are facilitated, and therefore the tackifying effect of alkyl polyether acrylate is improved; meanwhile, oxyethyl and oxypropyl jointly regulate and control the tightness degree of a network structure, so that a calcium and magnesium ion'salt bridge 'tackifying effect is presented. According to the carbon dioxide-salt double-response polymer thickening agent provided by the invention, the viscosity of the thickening agent is improved through carbon dioxide and calcium and magnesium ions, and meanwhile, a fracturing fluid has certain imbibition oil displacement capacity after gel breaking.

The invention relates to the technical field of microbial engineering, and particularly discloses a Gordonia sp. DH2, a biological oil displacement agent and application of the Gordonia sp. DH2, the Gordonia sp. DH2 is preserved in China Center for Type Culture Collection on June 3, 2024, the preservation number is CCTCC NO: M 20241126, and the Gordonia sp. DH2 is classified and named as Gordonia sp. DH2. The Gordonia provided by the invention can degrade saturated hydrocarbons and sulfur-containing compounds in crude oil, and the saturated hydrocarbons and the sulfur-containing compounds are used as a unique carbon source to generate a biological oil-displacing agent, degrade, disperse and emulsify the crude oil, so that the Gordonia can be used for improving the fluidity of the crude oil in a stratum and increasing the recovery rate of the crude oil.

The invention discloses a CCUS experimental device and method for carbon dioxide flooding and storage, and relates to the technical field of petroleum engineering. The device comprises a three-dimensional oil reservoir physical model, a fluid injection system, a fluid collecting and metering system, a resistivity monitoring system and a fluid migration observation system. The three-dimensional oil reservoir physical model is used for constructing a simulated stratum, and a development well pattern system is installed on the simulated stratum; the fluid injection system is connected with the injection well; the fluid collecting and metering system is connected with the production well; the resistivity monitoring system is provided with a plurality of monitoring points on the simulated stratum; the fluid migration observation system is used for observing a migration path of supercritical carbon dioxide in the three-dimensional oil reservoir physical model; and the distributed optical fiber monitoring system is arranged in the simulated stratum. According to the device and the method, oil reservoir water injection exploitation and CO2 injection oil displacement and CO2 storage stability simulation experiments in the later development period can be realized.

The invention relates to the field of oil exploitation, in particular to temperature-resistant and salt-resistant efficient gel as well as a preparation method and application thereof, which are used for solving the problems that the efficiency of the gel is influenced and the oil displacement effect is reduced due to poor high temperature resistance and salt resistance and easiness in failure of the existing polyacrylamide hydrogel. According to the preparation method, through a copolymerization technology, various monomers with excellent temperature resistance and salt resistance, such as acrylamide, methacryloyloxyethyl trimethyl ammonium chloride, 2-acrylamido-2-methylpropanesulfonic acid, a temperature-resistant monomer and a hydrophobic macromonomer, are integrated, so that the gel can bear a relatively high temperature without degradation or performance reduction; the prepared oil displacement gel has good stability in a high-salinity environment, does not lose an oil displacement effect due to the existence of salt, ensures the activity and stability of the gel in a high-temperature and high-salt-content oil reservoir environment, and obviously enhances the oil displacement efficiency of the gel in crude oil exploitation, thereby greatly improving the exploitation efficiency and recovery rate of crude oil.

The invention relates to an oil field auxiliary agent, and particularly discloses a temperature-resistant salt-resistant nano fluid oil displacement agent and preparation and application thereof, the temperature-resistant salt-resistant nano fluid oil displacement agent comprises the following components by weight: 5-12 parts of modified nano SiO2 particles, 10-20 parts of a nonionic surfactant, 10-30 parts of a gemini benzoxazine surfactant, 1-5 parts of a dispersant, 10-20 parts of a mutual solvent, and 20-50 parts of water; wherein the modified nano SiO2 particles are obtained by modifying nano SiO2 particles through a macromolecular coupling agent. The nano-fluid oil-displacing agent has the beneficial effects that the recovery efficiency can be improved when the nano-fluid oil-displacing agent is used for exploiting a high-temperature and high-salt oil reservoir, and the nano-fluid oil-displacing agent is good in temperature resistance and salt resistance, small in particle size and capable of remarkably reducing the oil-water interfacial tension.

According to the carbon dioxide oil displacement tank capable of automatically adjusting the pressure, during daily storage, the change speed and amplitude of the pressure in the tank are maximum, so that the stability of equipment can be influenced, an air bag is arranged in a third air cavity, and when the pressure in the third air cavity changes, the air bag is closed, so that the stability of the equipment is improved. The air bag can be matched with the third electric valve and the second electric valve to release or suck air so as to adjust pressure change, the speed and amplitude of the pressure change are slowed down to be within a controllable range, and therefore the stability of air stored in the device is improved, the interior of the tank body is divided into three storage units, and the storage effect is good. The third air cavity, the second air cavity and the first air cavity are sequentially arranged from inside to outside, when the first air cavity leaks, the third air cavity and the second air cavity are in a closed state and do not leak with the first air cavity at the same time, the capacity of the first air cavity is the minimum, the capacity of the third air cavity is the maximum, and if the first air cavity leaks, the loss can be reduced to the minimum. Therefore, the safety of the device can be improved.

The invention provides a composite surfactant for oil displacement of a hypersalinity oil reservoir and a preparation method of the composite surfactant, and relates to the technical field of petrochemical engineering. The composite surfactant is prepared from the following components in percentage by weight: 0.1 to 0.3 percent of anionic-nonionic surfactant, 0.01 to 0.03 percent of cationic surfactant and the balance of formation water, wherein the anionic-nonionic surfactant is prepared by the following steps: reacting a hydroxyl-containing compound with ethylene oxide to obtain polyoxyethylene ether, then carrying out esterification modification by using aconitic acid modified rosin, then sulfonating by using a sulfonating agent, and finally neutralizing. The composite surfactant shows relatively low interfacial tension under the condition of hypersalinity (50000-200000 mg / L), is high in stability, and can be used for improving the recovery efficiency of hypersalinity oil reservoirs.

The invention discloses a microbial oil-displacing active agent and a preparation method thereof, and belongs to the technical field of microbial oil recovery. The microbial oil-displacing active agent comprises the following components in percentage by mass: 5-15% of functionalized xanthan gum, 15-25% of a microbial agent and the balance of water, through the synergistic effect of the functionalized xanthan gum and the microbial agent, the oil displacement effect of the microbial oil displacement active agent is remarkably improved, and the functionalized xanthan gum not only serves as a thickening agent and an oil displacement agent, but also provides a good carrier and protection effect for the microbial agent, so that the microbial agent can be more uniformly distributed in an oil reservoir, and the oil displacement efficiency of the microbial agent is improved; the microbial oil displacement technology is adopted, the problem that a traditional chemical oil displacement agent pollutes the environment is solved, good environment friendliness is achieved, the functionalized xanthan gum and the microbial agent both have good biodegradability and can be naturally degraded in the oil reservoir environment, long-term environmental pollution cannot be caused, and the requirement for environmental protection is met.

The invention discloses offshore oilfield chemical flooding fully-closed instant curing injection allocation process equipment and a using method. The offshore oilfield chemical flooding fully-closed instant curing injection allocation process equipment comprises an efficient dispersion system, an instant curing system and a high-pressure injection system which are sequentially connected. The efficient dispersing system comprises a feeding mechanism and a dispersing mechanism which are connected with each other; the instant curing system comprises a high-viscosity efficient ager, a supergravity ager, a low-shear feeding pump, a tubular rotational flow ager and a mother liquor duplex filter which are communicated in sequence; the high-pressure injection system comprises a high-pressure polymer injection pump, a high-pressure tubular rotational flow ager, a first high-pressure internal part coupling disperser and a second high-pressure internal part coupling disperser which are connected in sequence. By taking the stator and rotor disperser, the internal part coupling dynamic disperser, the high-viscosity and high-efficiency ager and the supergravity ager as a core, the device has the characteristics of low carbon, high efficiency, miniaturization, modularization, distribution and the like, the polymer dissolving and curing time is shortened, the equipment weight and the occupied area are reduced, and the polymer solution viscosity and the oil displacement efficiency are improved.

The invention discloses a high-pressure CO2 oil displacement micro-fluidic chip device which comprises an upper polar plate, a middle partition plate, a lower polar plate, a speed measurement module, a porous medium radial flow module and a liquid outlet module, the speed measurement module is arranged on the upper surface of the middle partition plate; the porous medium radial flow module and the liquid outlet module are arranged on the upper surface of the lower polar plate; the upper polar plate, the middle partition plate and the lower polar plate are sequentially stacked from top to bottom; the speed measurement module is connected with the porous medium radial flow module; and the porous medium radial flow module is connected with the liquid outlet module. According to the device disclosed by the invention, a pore throat structure in rock is simulated by constructing a micron-sized or even smaller complex flow channel, and the CO2 flooding crude oil flow characteristic and the CO2 distribution rule are simulated; a transparent visualization device structure is designed, and visualization of the action mechanism of the CO2 oil displacement system and the reservoir fluid distribution characteristics is guaranteed.

The invention provides a composite oil-displacing agent for heavy oil cold production and a preparation method thereof, and belongs to the technical field of oilfield chemistry. The composite oil displacement agent is prepared from the following components in parts by weight: 42 to 48 parts of acrylamide, 12 to 14 parts of acrylic acid, 16 to 18 parts of N, N-dimethylformamide, 9 to 10 parts of 2-acrylamido-2-methylpropanesulfonic acid, 10 to 12 parts of allyl 2-ethylbutyrate, 0.5 to 1 part of 2, 2-dimethylolbutanol, 6 to 7 parts of an interfacial tension regulator, 9 to 10 parts of a penetration enhancer, 0.35 to 0.45 part of a slow release initiator, 1 to 2 parts of a stabilizer and 180 to 200 parts of deionized water. A polymerization product obtained by adopting the components can remarkably improve the stability and viscosity of the composite oil-displacing agent, more effectively carry out heavy oil, improve the adsorption capacity of a surfactant on an oil-water interface, reduce the tension of the oil-water interface and improve the recovery ratio.

The invention discloses a molecular dynamics simulation method for CO2-ion oil displacement, and belongs to the technical field of CO2 oil displacement. The method comprises the steps that an oil molecule model, a water molecule model, a CO2 molecule model, a CaCl2 molecule model and a graphene plate model corresponding to target oil reservoir characteristics are established; carrying out geometric structure optimization on each model; the optimized molecular model is assembled into a 'CO2-CaCl2-H2O' ternary displacement system, and molecular dynamics simulation is executed; during simulation, an NVT ensemble is selected, periodic boundary conditions are applied, a COMPASS II force field is adopted, atomic potential parameters are configured, and after operation energy is minimized and temperature is initialized, displacement process simulation is executed; and quantitatively evaluating the oil displacement effect of the displacement medium of the 'CO2-CaCl2-H2O' ternary system on the basis of the trajectory file output by simulation. According to the method, the behavior of molecules under the synergistic effect of multiple displacement media can be better explained, the oil displacement micromechanism under the synergistic effect of the multiple displacement media is embodied, and the method has important significance for optimizing the compact oil reservoir development effect and improving the recovery efficiency.

The invention provides a polycarbonate polyether sulfate salt surfactant as well as a preparation method and application thereof, and belongs to the technical field of surfactants. The polycarbonate chain segment endows the polymer with certain rigidity and stability, the polyether chain segment provides good hydrophilicity and flexibility, and the sulfate salt group enhances the surface activity of the polymer. The polycarbonate polyether sulfate salt surfactant provided by the invention is strong in emulsibility, good in low-temperature solubility and strong in capability of reducing surface tension at low concentration, a rigid structure of a polycarbonate chain segment can be more easily decomposed by microorganisms, environmental residues are reduced, and the surfactant is environment-friendly. The method can be used in the fields of personal care products, household cleaning products, textile printing and dyeing assistants, coating and ink assistants or oil displacement agents for oil fields.

The invention relates to an oil displacement polymer rheological impedance characteristic characterization method based on an equivalent circuit method, which comprises the following steps: obtaining the total rheological impedance and phase angle of an oil displacement polymer under different shear rate conditions, and constructing and dividing a polymer rheological impedance characteristic characterization data set under a shear effect; constructing a series equivalent model for representing the rheological impedance characteristics of the polymer for oil displacement; constructing a parallel equivalent model for representing the rheological impedance characteristics of the polymer for oil displacement; constructing a composite equivalent model for representing the rheological impedance characteristics of the polymer for oil displacement; a grey wolf algorithm is introduced, on the basis of constructing a data set representing the rheological impedance characteristics of the polymer for oil displacement under the shear effect, the application limit of the equivalent model at different shear rates is optimized, and quantitative representation of the rheological impedance characteristics of the polymer for oil displacement is achieved. According to the method, the rheological impedance of the polymer for oil displacement under the shear effect is quantified, and quantitative and scientific characterization of the rheological impedance characteristic in the rheological property evaluation process of the polymer is ensured.

The invention discloses a high-temperature-resistant oil-displacing agent for an oil field and a preparation method thereof, and relates to the technical field of oilfield exploitation. The prepared oil displacement agent for the oil field comprises the following raw materials in parts by weight: 15-25 parts of polyacrylamide, 1-5 parts of nano silicon dioxide, 25-35 parts of an enhanced surfactant and 40-60 parts of water. The oil-displacing agent is prepared by mixing and stirring the raw materials, and has excellent oil-displacing performance, low surface tension and excellent high-temperature resistance when being used in the oilfield exploitation process; compared with a traditional surfactant, due to the introduction of the enhanced surfactant, the high temperature resistance and the oil displacement efficiency of the oil displacement agent are improved.

The invention relates to the technical field of oil-displacing agents, in particular to a polyacrylamide-containing oil-displacing agent and a preparation method thereof.The polyacrylamide-containing oil-displacing agent is prepared from, by weight, 35-40% of functionalized polyacrylamide, 5-8% of loading filler, 2-3% of n-amyl alcohol, 5-7% of cyclohexane and the balance water; the polyacrylamide is subjected to functional modification, and the loading filler loaded with the zwitterionic surfactant is added, so that the oil-displacing agent can still keep a good synergistic effect in a complex high-temperature and high-salt environment, and a good oil-displacing characteristic is exerted.

The invention relates to the technical field of petroleum and natural gas engineering, and discloses an optimization method for carbon dioxide flooding and sealing collaborative heat collection. On the basis of the target oil reservoir area, parameter variables used for optimizing carbon dioxide oil displacement and sealing collaborative heat recovery are determined; inputting the parameter variables and the target oil reservoir area into a pre-constructed classification-assisted hierarchical learning pre-screening model and a differential evolution algorithm agent model, and determining the cumulative oil production, the cumulative heat production and the carbon dioxide sequestration amount; based on the cumulative oil production, the cumulative heat production and the carbon dioxide storage amount, determining a to-be-optimized target function; and the parameter variables are optimized, and the maximum net present value of the target function is selected as the optimal scheme of carbon dioxide flooding and storage collaborative heat collection. According to the invention, the calculation speed and precision of the optimal scheme and the accuracy of the calculation result can be provided.

The invention discloses a kind of silicon / carbon-based nano chemical empowered polymer viscosity reducer and preparation method thereof, relate to oilfield chemical technology field.The preparation method of the viscosity reducer of the present invention is:Nano silicon dioxide or carbon quantum dot are modified using a silane coupling agent with a double bond, N hydroxymethyl acrylamide, 2 acrylamido 2 methylpropane sulfonic acid, α olefin sulfonate sodium monomer and modified nano silicon dioxide or modified carbon quantum dot are sequentially added in deionized water afterwards, peroxide is used as initiator, polymer chain is grafted onto hydrophobic nano silicon dioxide or modified carbon quantum dot by free radical copolymerization in aqueous solution, obtain target product.The viscosity reducer of the present invention has excellent long-term stability and shear resistance under the conditions of high temperature (130 DEG C) high salt (mineralization 250,000 mg / L), can significantly reduce crude oil viscosity 90% and above in underground conditions, while it can reduce oil-water interfacial tension, improve oil displacement efficiency, thus significantly increase crude oil recovery rate.

The invention relates to the technical field of chemical oil displacement, and particularly discloses a self-emulsifying nano-composite modifying and flooding agent for an oil field and a preparation process of the self-emulsifying nano-composite modifying and flooding agent. The invention relates to a self-emulsifying nano composite modifying and flooding agent for an oil field. The self-emulsifying nano composite modifying and flooding agent is prepared from the following 100 parts by mass of raw materials: 3-5 parts of amphiphilic nano silicon dioxide, 1-2 parts of a zwitterionic surfactant, 0.5-1 part of a nonionic surfactant and the balance of water, the zwitterionic surfactant comprises hydroxyl sulfobetaine and imidazoline, and the zwitterionic surfactant comprises hydroxyl sulfobetaine and imidazoline; and the non-ionic surface active agent is an ethyoxyl-propoxyl block copolymer. The self-emulsifying nano-composite modifying and flooding agent prepared by the invention effectively realizes the balance of low interfacial tension and self-emulsifying efficiency.

The invention provides a high-temperature-resistant lipopeptide reinforced foam flooding system and a screening method and application, and relates to the technical field of microbial oil recovery, the high-temperature-resistant lipopeptide reinforced foam flooding system comprises the following steps: S1, screening applied oil reservoirs; s2, based on the oil reservoir temperature and the crude oil viscosity selected in S1, screening a high-temperature-resistant lipopeptide reinforced foam flooding system; the high-temperature-resistant lipopeptide reinforced foam oil displacement system comprises a foaming agent, a foam stabilizer, gas and water, the foaming agent comprises one or more of surfactin (C12-18), scabrin (C14-18), iturin (C14-17), deocytin, serratia marcescens and mucin fermentation liquor, and the foaming agent comprises one or more of lipopeptide, a foaming agent and a foaming agent. The foam stabilizer comprises one or more of biosynthetic nano-silver, nano-iron, nano-copper, nano-zinc, nano-zirconium and nano-nickel. The method has the beneficial effects that the oil reservoir application range is wide, the pertinence is high, the field test effect is good, and a high-temperature-resistant lipopeptide enhanced foam oil displacement system is specifically constructed according to the temperature-resistant stability characteristics of lipopeptide surfactants and biosynthetic nano materials of different structures and types.

The invention provides a medium-low permeability oil reservoir rhamnolipid foam oil displacement system and a screening method and application, and relates to the technical field of microbial oil recovery, the medium-low permeability oil reservoir rhamnolipid foam oil displacement system comprises the following steps: S1, screening an applied oil reservoir; s2, determining a rhamnolipid foam flooding system based on the oil reservoir mineralization degree; s3, based on the porosity of the oil reservoir, the injection mode of a rhamnolipid foam oil displacement system is determined, the rhamnolipid foam oil displacement system comprises a foaming agent, a foam stabilizer, nitrogen and water, the foaming agent comprises one or more of dirhamnose difat, dirhamnose monofat, single rhamnose monofat and single rhamnose difat fermentation liquor, and the foam stabilizer comprises one or more of dirhamnose difat, dirhamnose monofat, single rhamnose monofat and single rhamnose difat fermentation liquor. The foam stabilizer is prepared from one or more of xanthan gum, welan gum, Wollan gum, Dide gum, gellan gum, rhamnose gum, diidine gum, plant cellulose and bacterial cellulose. The method has the beneficial effects that the oil reservoir application range is wide, the pertinence is high, the field test effect is good, efficient generation and long-acting migration of foam in the oil reservoir are guaranteed, green and high-quality development of old oil fields is promoted, and achievement of the national dual-carbon strategy is assisted.

The invention discloses a silicon / carbon-based nano chemically-energized polymer viscosity reducer and a preparation method thereof, and relates to the technical field of oilfield chemistry. The preparation method of the viscosity reducer comprises the following steps: modifying nano silicon dioxide or carbon quantum dots by using a silane coupling agent with double bonds, then sequentially adding N-hydroxymethyl acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, a sodium alpha-olefin sulfonate monomer and the modified nano silicon dioxide or the modified carbon quantum dots into deionized water, and uniformly stirring to obtain the viscosity reducer. A peroxide is used as an initiator, and a polymer chain is grafted to the hydrophobic nano silicon dioxide or the modified carbon quantum dots through a free radical copolymerization reaction in an aqueous solution to obtain a target product. The viscosity reducer disclosed by the invention has excellent long-term stability and shear resistance under the conditions of high temperature (130 DEG C) and high salinity (the degree of mineralization is 250,000 mg / L), can greatly reduce the viscosity of crude oil by 90% or more under the underground condition, and can reduce the oil-water interfacial tension and improve the oil displacement efficiency, thereby greatly improving the recovery rate of the crude oil.