57results about How to "Strong oil washing ability" patented technology

The invention relates to an oil-displacement surfactant composition, a preparation method and application, and mainly solves the problems that conventional surfactants are bad in oil displacement efficiency in the process of tertiary oil recovery, and an oil displacement system damages stratums and oil wells, corrodes equipment and pipelines and cause demulsification difficulty because of a contained inorganic base. The employed oil-displacement surfactant composition comprises a cationic surfactant and an anionic-nonionic surfactant with the molar ratio of 1:0.01-1:100, wherein the anionic surfactant is at least one selected from quaternary ammonium salts or quaternary amine bases, and the anionic-nonionic surfactant has the molecular general formula shown in the specification, and the in general formula, M is any one of alkali metals, alkali earth metals and ammonium radical. The technical scheme relatively well solves the above problems, and is applicable to an enhanced oil recovery process of oil fields.

The invention relates to a surfactant composition for chemical displacement of reservoir oil and a preparation method thereof, mainly for solving the problems that the conventional surfactant is poor in oil displacement efficiency in the tertiary oil recovery process and an oil displacement system containing inorganic base damages stratums and oil wells, corrodes equipment and pipelines and results in difficult demulsification. The surfactant composition provided by the invention comprises a cationic surfactant and an anionic-nonionic surfactant, wherein the cationic surfactant is at least one of quaternary ammonium salt and quaternary ammonium alkali; the anionic-nonionic surfactant is a surfactant containing an ethyoxyl nonionic group and a carboxyl or sulfonic acid group anionic group; and the molar ratio of the cationic surfactant to the anionic-nonionic surfactant is (1:0.01)-(1:100); and by the adoption of the surfactant composition and the preparation method of the surfactant composition, the above problems can be well solved. The surfactant composition can be applied to tertiary oil recovery process of an oil field.

The invention relates to a method for exploiting residual crude oil in a low-permeability oilfield by using a polymer micro/nanoparticle, comprising the following steps of: (1) carrying out prior period water drive on the low-permeability oilfield; (2) measuring the average throat radius of the low-permeability oilfield to determine the particle size r of the polymer micro/nanoparticle, wherein the particle size r of the polymer micro/nanoparticle meets a formula shown as the specification; (3) carrying out copolymerization by using a distillation-precipitation method according to the determined particle size r of the polymer micro/nanoparticle to obtain the polymer micro/nanoparticle; and (4) injecting the polymer micro/nanoparticle obtained in the step (3) into an oil layer, and carrying out the following water drive on the low-permeability oilfield. The method has the advantages that the used polymer micro/nanoparticle injection system can selectively enter large, medium and small ducts, a stronger wave and volume expanding function and an oil washing capacity are achieved, the residual oil on a low-permeability layer is better exploited, the crude oil exploiting yield is increased, and the economic benefit is increased.

The invention relates to a preparation method and an application of alkali-free viscoelastic surfactant composition and mainly solves the problem of poor flooding effect of an existing flooding systemunder the condition of the high-temperature and low-permeability reservoir. According to the technical scheme, the alkali-free viscoelastic surfactant composition is prepared from a betaine surfactant, an anionic surfactant and water, wherein the betaine surfactant is represented as the formula (I) in the description; the anionic surfactant is selected from at least one of structures shown as theformula (II) in the description; in the formula (I), R1 is selected from any one of C8-C29 alkyl and alkenyl, and R2 and R3 are independently selected from C1-C5 alkylidene and hydroxyl substituted alkylidene; in the structural formula (II), X is selected from at least one of carboxylate radical and sulfonate radical. With the adoption of the technical scheme that the mole ratio of an ampholyticsurfactant to the anionic surfactant is 1:0.01-1:100, the technical problem is solved better, and the alkali-free viscoelastic surfactant composition can be applied to tertiary oil recovery of an oilfield.

The invention provides an active monomer shown in a formula (I). The invention further provides a polymeric surfactant shown in formula (II). The preparation method comprises the following step of: performing a chain transfer reaction on 1-40 parts by weight of acrylamide, 1-20 parts by weight of anion monomers with double bonds, 1-30 parts by weight of the active monomer according to the claim 1, 50-100 parts by weight of deionized water and 0.001-2 parts by weight of chain transfer agent under the effect of an initiator. The polymeric surfactant has the double performances of the polymer and the surfactant, has good oil scrubbing capacity, can be used for improving the recovery efficiency of petroleum, and has wide application prospect in thickened oil recovery. In addition, the polymeric surfactant further has solubilizing power, reversible gathering capacity, salt resistance, temperature resistance, and resistance to mechanical, biological and oxydative degradation.

The invention relates to viscoelastic surfactant composition for oil displacement as well as an application of the composition as an oil displacing agent and mainly solves the problem that surfactantshave low oil displacement efficiency under the high-temperature medium/low-permeability condition in the prior art. The viscoelastic surfactant composition for oil displacement is prepared from an ampholytic surfactant shown in formula (I) and organic acid salt, wherein the organic acid salt is selected from at least one of organic acid salts shown in formula (II); in the formula (I), R1 is selected from at least one of C8-C29 alkyls and alkenyls, and R2 and R3 are independently selected from at least one of C1-C5 alkylenes or hydroxyl substituted alkylenes; in the formula (II), X is selectedfrom at least one of carboxylate and sulfonate radicals, and Y is selected from at least one of hydrogen, alkyl, hydroxyl and halogen. With the adoption of the technical scheme, the technical problemis better solved, and the composition can be applied to oil displacement production of oil fields.

The invention relates to a surfactant composition for tertiary oil recovery and a preparation method thereof, mainly for solving the problems that the existing surfactant has poor oil displacement efficiency in tertiary oil recovery, inorganic base contained in a displacement of reservoir oil system damages the stratum and oil wells, corrodes equipment and pipelines, and results in difficult emulsion breaking. The surfactant composition comprises a cationic surfactant and an anion-nonionic surfactant, wherein the cationic surfactant is any one of quaternary ammonium salt and quaternary amine alkali, the anion-nonionic surfactant contains ethyoxyl nonionic group and carboxyl or sulfonic acid group anionic group, and the molar ratio of the cationic surfactant to the anion-nonionic surfactant is 1:0.01-1:100. Due to adoption of the surfactant composition and the preparation method, the above problems can be well solved. The technical scheme can be used in the oil field tertiary oil production process.

The invention relates to a with-production without-injection-type isolated well point potential tapping and effect raising method, which mainly solves the problem of poor developing and potential tapping effects as the existing with-production without-injection-type isolated well point is imperfect in production and injection and has no external energy source. The method is characterized by comprising the following steps: (1) a target well is optimally selected: based on the position of the isolated well point and in combination of cementing quality, perforation interpretation data, fine reservoir description results, fine residual oil research results, reservoir use condition evaluation data and the like, a target well is selected comprehensively and optimally; (2) the potential tapping time for the target well is determined: according to the dynamic development trend of the target well, a decline rule and the current production condition, the potential tapping time is determined, andpotential tapping is selected to be developed at the time when the fluid volume declines quickly and the fluid supply drops near shortage; (3) section optimization is carried out on the target well;(4) a potential tapping scheme is determined; and (5) field construction is carried out. The method can solve the problem that the isolated well is short of energy, and can thus realize the purpose ofimproving the remaining reserve recovery degree of the isolated well.

The invention relates to a viscoelastic surfactant composition for oil displacement and a preparation method and application of the viscoelastic surfactant composition. The problem of poor oil displacement effect of an existing oil displacement system under the condition of a low-permeability oil reservoir is mainly solved. According to the technical scheme of the viscoelastic surfactant composition for oil displacement and the preparation method and application of the viscoelastic surfactant composition, a viscoelastic betaine surfactant composition suitable for low permeability oil fields isadopted, and the viscoelastic betaine surfactant composition comprises a betaine surfactant and an anionic surfactant, wherein the betaine surfactant is shown in the following formula (I); the anionic surfactant is at least one of formula (II); R<1> is selected from any one of alkyl and alkenyl of C<6>-C<29>, R<2> and R<5> are selected from any one of alkylene and hydroxyl-substituted alkylene ofC<1>-C<22>, m+n is equal to 0-100, and x+y is equal to 0-100; and the molar ratio of an amphoteric surfactant to the anionic surfactant is (1 to 0.01) to(1 to 100), the problem of poor oil displacement effect of the existing oil displacement system under the condition of the low-permeability oil reservoir is better solved, and the viscoelastic surfactant composition for oil displacement can be used in oil displacement production in the oil fields.(Please see the specification for the formula).

The invention discloses a preparation method of a carbon quantum dot modified polystyrene oil displacement material, which comprises the following steps: uniformly dissolving citric acid in deionizedwater, carrying out one-step synthesis by a microwave method, and purifying the solution to obtain carboxylated carbon quantum dots; carrying out a reversible addition fragmentation transfer method reaction to synthesize single primary amine polystyrene; and finally, stirring the carboxylated carbon quantum dots, mono-primary amino polystyrene and a 1,1-carbonyldiimidazole condensing agent at 30-50 DEG C to react for 3 hours, and pouring the solution into absolute ethyl alcohol to separate out a polymer. The polymer is carbon quantum dot modified polystyrene and is used as an oil displacementmaterial. The oil displacement material synthesized by the method can effectively reduce interfacial tension and has good oil washing capability; when the polymer is applied to oil displacement, compared with water displacement and carboxylated carbon quantum dot solution displacement, the recovery ratio is obviously increased.

The invention relates to viscoelastic betaine surfactant composition for oil displacement and mainly solves the problems that existing surfactants have poor oil displacement effects as oil displacingagents in high-temperature medium/low-permeability reservoirs and cause huge damage to stratums and oil wells due to contained alkali. The viscoelastic betaine surfactant composition is prepared froma betaine surfactant and an anionic surfactant in the molar ratio being (1:0.01)-(1:100); the betaine surfactant is selected from at least one of structures shown in formula (I), R1 is selected from any one of C8-C29 alkyls and alkenyls, and R2 and R3 are independently selected from any one of C1-C5 alkylenes; the anionic surfactant is selected from at least one of structures shown in formula (II). With the adoption of the technical scheme, the problems are better solved, and the composition can be applied to oil displacement production of oil fields.

The invention provides a viscosity-reducing oil-displacing agent for viscosity-reducing combination flooding of a common heavy oil reservoir as well as a preparation method and application of the viscosity-reducing oil-displacing agent, and belongs to the field of oilfield chemistry. The viscosity-reducing oil-displacing agent for viscosity-reducing combination flooding of the common heavy oil reservoir, provided by the invention, comprises the following components in percentage by mass: 30-40% of a nano viscosity reducer, 10-20% of isopropanolamide, 5-10% of imidazoline, 10% of low-carbon alcohol and the balance of water. The viscosity-reducing oil-displacing agent provided by the invention is mainly applied to viscosity-reducing combination flooding of a common heavy oil reservoir, and by compounding with a polymer, the dual effects of viscosity-reducing chemical flooding and polymer flooding are exerted, so that the viscosity-reducing oil-displacing agent not only can reduce the viscosity and wash oil, but also can enlarge the swept volume, and can effectively improve the recovery ratio of the common heavy oil reservoir.

The invention provides a low-tension viscosity-reducing heavy oil washing agent for cold production of a common heavy oil reservoir as well as a preparation method and application thereof, belonging to the field of oilfield chemistry. The low-tension viscosity-reducing thick oil washing agent comprises the following components in percentage by mass: 30%-40% of alcohol ether sulfonate, 10%-20% of phenolic ether carboxylate, 5%-10% of sodium carbonate and 10% of low-carbon alcohol, with the balance being water. When the low-tension viscosity-reducing heavy oil washing agent is applied to a common heavy oil reservoir with a formation water mineralization degree of 0-100,000 mg/L and a calcium and magnesium ion concentration of less than or equal to 2,000 mg/L, the low-tension viscosity-reducing heavy oil washing agent has the characteristics that oil washing efficiency is more than or equal to 81.5%, a viscosity reduction rate is more than or equal to 98.3%, oil-water interfacial tensionis less than or equal to 3.3*10<-3> mN/m and the like. The preparation method is simple in process, low in cost and friendly to environment.

The invention discloses a polymer having surface activity function, a preparation method and an application thereof. The polymer contains a structural unit A, a structural unit B and a structural unit C, the structural unit A is shown in a formula (1), the structural unit B is shown in a formula (2), the structural unit C is shown in a formula (3), by taking the weight of the polymer as a reference, the content of the structural unit A is 5-60 wt%, the content of the structural unit B is 30-90 wt%, the content of the structural unit C is 0.1-10 wt%; and the viscosity average molecular weight of the polymer is 18 million-28 million. The polymer has the advantages of good water solubility, strong tackifying ability, and heatproof salt-resistance performance and good surface activity, so that the polymer has good oil-washing effect, and can be used as an oil displacement polymer of mid-low permeability reservoir.

The invention relates to a surface active agent composition for chemical displacement of reservoir oil, and a preparation method and application thereof, and mainly solves the problems of poor displacement efficiency in a tertiary oil recovery process, and harm to the stratum and the oil field, corrosion of equipment and pipeline and difficult demulsification due to oil inorganic alkali contained in displacement system. The invention adopts the surface active agent composition comprising a cationic surface active agent and an anionic-non-ionic surface active agent. The cationic surface active agent is at least one selected from the group consisting of quaternary ammonium salt or quaternary ammonium alkali; and the anionic-non-ionic surface active agent is represented by a molecular general formula shown as (A) or (B), wherein M represents one of an alkali metal, an alkaline earth metal and ammonium, m and n are selected from 0-14, and x and y are selected from 0-100. The technical scheme well solves the above problems, and can be used in tertiary oil recovery process.

The invention relates to an oil displacing composition containing a sulphobetaine type surfactant and a preparation method and application thereof. The problems that through existing production technologies, macromolecular polymers in combination flooding are prone to causing reservoir blocking and difficult injection in medium-low-permeability oil reservoirs are mainly solved. The oil displacingcomposition contains the betaine type ampholytic surfactant and inorganic salts, wherein the structure of the betaine type ampholytic surfactant is shown in the formula (I), R1 is selected from any one of C6-C29 alkyl and vinyl, R3 and R4 are selected from any one of C1-C12 alkylene and hydroxyl-substituted alkylene, the sum of m and n is 0-100, and the sum of x and y is 0-100; the molar ratio ofthe betaine type ampholytic surfactant to the inorganic salts is 1: 0.01 to 1: 100. By means of the technical scheme, the technical problems are well solved, and the oil displacing composition can beused for oil displacing production of oil fields. Please see the specification for the formula (I).

The invention relates to a method for injecting an oil-displacing agent into an oil layer by utilizing fracturing prepad fluid to improve the recovery efficiency. By utilizing the opportunity of only one-time fracturing transformation, energy-increasing, huff and puff, replacement and imbibition three-time oil recovery chemical agents are added into the fracturing prepad fluid, the energy-increasing, huff and puff, imbibition and oil-displacing chemical agents are injected into the oil layer to improve the recovery efficiency, the yield of a fractured well can be greatly increased, the oil increasing effect is obvious, the yield increasing effect of fracturing transformation is improved, and the single well recovery efficiency is increased. The huff and puff, imbibition and oil-displacing chemical agent system has the advantages of high oil washing effect, low viscosity, high permeability, low corrosivity and the like. According to the method for injecting the oil-displacing agent into the oil layer by utilizing fracturing prepad fluid to improve the recovery efficiency, secondary and tertiary oil recovery processes are combined with fracturing transformation, huff and puff, imbibition and oil-displacing chemical agents are injected into an oil layer to improve the recovery efficiency, the yield of the fractured well can be greatly increased, the oil increasing effect is obvious, the yield increasing effect of fracturing transformation is improved, the single well recovery efficiency is increased, and important significance is achieved on development of unconventional tight oil reservoirs at home and abroad at present.

The invention relates to a preparation method and an application of an alkali-free viscoelastic surfactant for a low-permeability reservoir and mainly solves the problem of poor flooding effect of anexisting flooding system under the condition of the high-temperature and low-permeability reservoir. According to the technical schemes, alkali-free viscoelastic surfactant composition suitable for alow permeability oilfield is prepared from a betaine surfactant, an anionic surfactant and water, wherein the betaine surfactant is represented as the formula (I) in the description; the anionic surfactant is selected from at least one of structures shown as the formula (II) in the description; in the formula (I), R1 is selected from any one of C8-C29 alkyl and alkenyl, and R2 and R3 are independently selected from C1-C5 alkylidene and hydroxyl substituted alkylidene; in the structural formula (II), R6 is selected from C1-C4 alkyl, and X is selected from any one of carboxylate radical and sulfonate radical. With the adoption of any one of the technical schemes, the technical problem is solved better, and the alkali-free viscoelastic surfactant can be applied to tertiary oil recovery of theoilfield.