172results about How to "Improve oil washing efficiency" patented technology

The invention provides a foaming agent for low gas liquid ratio foam flooding for improving recovery ratio of common heavy oil reservoir and an injection method thereof. The foaming agent is prepared from a nonionic-anionic surfactant, a betaine type amphoteric surfactant and water, wherein the nonionic-anionic surfactant accounts for 0.01 to 0.03 weight percent of the total weight; the betaine type amphoteric surfactant accounts for 0.05 to 0.3 weight percent of the total weight; and the balance is oil field injection water. The foaming agent has good foaming tendency, can reduce the interfacial tension of oil and water to the lowest under the condition of not adding alkali, and can give full play to the foam flooding and the improvement of conformance factor and displacement efficiency. On the basis of the foaming agent, when the gas liquid ratio is between 0.1:1 and 0.3:1 (volume ratio), the generated foam can improve the recovery ratio by over 10 percent, and the technology with low cost and good effect for improving the recovery ratio of the heavy oil reservoir is realized.

The invention relates to synthesis of polyoxyethylene fatty alcohol ether sulphonate, and complex formulation for tertiary oil recovery displacement agent, and belongs to chemical displacement agent technic field. The invention discloses a synthesis method of a surface active agent for tertiary oil recovery for a high-temperature, high salinity and high calcium and magnesium ion oil reservoir, and complex formulation for highly effective displacement agents. Polyoxyethylene fatty alcohol ether sulphate is reacted with a sulfonating agent under the action of catalyst to produce polyoxyethylene fatty alcohol ether sulphonate. Polyoxyethylene fatty alcohol ether sulphonate are used as main material which is complex formulated with heavy alkyl benzene sulfonate, water, polymerisate, etc. Compared with existing products, the displacement agent of the invention in the three-high system reduces the oil-water boundary tension ultra-low (10<-3>mN/m), and the boundary tension is not affected by temperature, degree of mineralization and the concentration of calcium and magnesium ions.

The invention relates to a profile controlling and flooding composition for high-temperature oil reservoirs with high salinity and an application of the composition in tertiary oil recovery of the high-temperature oil reservoirs with high salinity, and mainly aims at solving the problems of poor heat resistance and salt tolerance and low oil displacement efficiency of an oil displacement agent under the conditions of high temperature and high salinity in the prior art. The problems are well solved by virtue of the following technical scheme: the profile controlling and flooding composition for high-temperature oil reservoirs with high salinity is prepared from the following components in percentage by weight: (1) 0.01-3.0% of heat-resistant and salt-tolerant polyacrylamide microspheres, (2) 0.01-5.0% of anionic-nonionic surfactant and (3) 92.0-99.98% of injected water; and the profile controlling and flooding composition can be applied to field applications for increasing the recovery rate such as depth profile controlling, water plugging and oil displacement for tertiary oil recovery of the high-temperature oil reservoirs with high salinity.

The invention provides a foam oil displacement system with ultralow interfacial tension and a use method of the foam oil displacement system. The oil displacement system is formed by mixing raw materials in percentage by weight as follows: 0.1%-0.3% of a foaming agent, 0.05%-0.15% of an inorganic reagent, 0.01%-0.10% of a foam stabilizer and the balance of water, wherein the foaming agent is dodecyl dimethyl betaine, dodecyl hydroxysulfobetaine, dodecyl hydroxypropyl sulphobetaine, lauramide propyl hydroxysulfobetaine, lauramide propyl betaine, cocamidopropyl dimethylamine oxide, gemini oxidized tertamine, polyoxyethylene dodecanol ether sulfate or sodium dodecyl sulfate; the inorganic reagent is sodium hydroxide, anhydrous sodium carbonate or sodium metaborate; the foam stabilizer is partially HPAM (hydrolyzed polyacrylamide), acrylamide copolymer, PACHV (high-viscosity polyanionic cellulose) or HPMC (hydroxypropyl methyl cellulose).

The invention relates to a method for carrying out profile control on a fracture-type oil reservoir, which comprises the following steps of injecting 0.1 to 0.3 percent of zwitterionic polymer solution into an oil layer; suspending and carrying expansion-retarding 0.2 to 1.0 percent of salt-resistance high-intensity water-absorbent resin particles by a zwitterionic gel profile control agent and injecting the obtained product into a fracture of the oil layer; injecting 30 to 50m<3> of acrylamide gel; suspending 0.2 to 0.5 percent of water insoluble solid particles by the zwitterionic gel profile control agent and injecting the obtained product into the fracture; and alternately injecting 1,000m<3> of partially hydrolyzed polyacrylamide solution with a molecular weight of 15 million, degree of hydrolysis of 10 to 20 percent and 1,000m<3> of petroleum sulfonate surfactant solution, wherein the concentration of the hydrolyzed polyacrylamide solution is 0.05 to 0.15 percent and the concentration of the petroleum sulfonate surfactant solution is 0.2 to 0.5. According to the method, profile control and flooding effects of the fracture-type oil reservoir can be improved; water content of a fracture main direction oil well is reduced; and yield of crude oil of a fracture side direction oil well is increased.

The invention discloses an experimental device and experimental method for thickened oil pool mixed nano-fluid alternating CO2 microbubble flooding. The experimental device and experimental method forthickened oil pool mixed nano-fluid alternating CO2 microbubble flooding introduces mixed nano-particles and combines the advantages of CO2 microbubbles, the phenomena of gas channeling and gravity override of a thickened oil pool occurred during conventional CO2 gas-water alternate flooding can be effectively controlled through a mode of alternating injection, and the recovery efficiency of thethickened oil pool is improved. Compared with CO2 gas, dissolving and diffusing abilities of the CO2 microbubbles are greater in crude oil, buoyancy is smaller, thickened oil viscosity can be better reduced, the volume of thickened oil is expanded, and the sweep coefficient is increased; the mixed nano-fluid can fully combine the advantages of various nano-particles, wettability of oil pull rockscan be changed, the oil-water interfacial tension can be reduced, and the oil washing efficiency is improved; and in addition, the experimental device and experimental method for thickened oil pool mixed nano-fluid alternating CO2 microbubble flooding adopts the method of injecting a mixed nano-fluid slug on the upper part of an oil pool and a CO2 microbubble slug on the lower part, controlling ofthe phenomena of the gas channeling and the gravity override and improvement of the vertical sweep coefficient are helped.

The invention relates to a profile controlling and flooding composition of a high-temperature, high-salinity and low-permeability oil reservoir and application thereof in tertiary oil recovery of the high-temperature, high-salinity and low-permeability oil reservoir. The profile controlling and flooding composition aims at solving the problems that in the prior art, the heat resistant and salt resistant performance of an oil-displacing agent are poor and the flushing efficiency is low under the condition of the high-temperature, high-salinity and low-permeability oil reservoir. According to the technical scheme, the profile controlling and flooding composition of the high-temperature, high-salinity and low-permeability oil reservoir comprises, by weight, 0.01-3.0% of temperature and salt resistant polyacrylamide microspheres, 0.01-5.0% of anionic-nonionic surface active agent, and 92.0-99.98% of injected water, the problems are favorably solved, and the profile controlling and flooding composition can be used for on-spot application of oil recovery enhancement of deep profile controlling, water plugging, reservoir oil displacing and the like used in the tertiary oil recovery of the high-temperature, high-salinity and low-permeability oil reservoir.

The invention discloses a viscoelastic weak gel profile control agent which is applied in oil field and oil well water injection operation. The viscoelastic weak gel profile control agent comprises the following components in parts by weight: 0.15-0.25 part of viscoelastic surface activity polymer, 0.05-0.15 part of cross-linking agent, 0.001-0.005 part of conditioning agent, and 99.8-99.6 parts of water. The viscoelastic surface activity polymer comprises the following components in parts by weight: 20-30 parts of acrylic amide, 1-2 parts of 3,3-dimethylacrylic acid, 1.5-3.5 parts of 2-acrylamido-2-dodecyl ethanesulfonic acid and/or 1-4 parts of N,N-dimethyl-allyl-hexadecyl ammonium chloride, 60-75 parts of deionized water and 0.3-1 part of initiating agent. The initiating agent comprises the following components in parts by weight: 2.5-3.5 parts of ammonium persulphate and 1 part of sodium sulfite. The viscoelastic weak gel profile control agent of the invention has a certain gel strength, capacity for lowering oil-water surface tensility and adjustable gel forming time, can improve water injection profile, lower oil-water surface tensility, wash away residual oil in a pore canal and improve water injection recovery ratio.

The invention discloses a microsphere profile control and displacement agent used for petroleum exploitation, which is a dispersion system prepared from functional polymer solution and microspheres with diameter of 0.2 to 20 mum by mixing, wherein the microspheres have a concentration of 0.05 to 0.2wt percent. The invention further discloses a combined oil displacement system formed by using the foam profile control and displacement agent and a combined oil displacement method. The oil displacement is achieved by using a combined slug consisting of functional polymers from high viscosity to low viscosity and the microspheres, and is suitable for multiple kinds of anisotropic oil layers to effectively improve oil recovery, reduce ineffective water circulation, and improve economic benefits. Through the effective combination, the system can improve the recovery greatly, improve the total recovery to 70 to 89 percent or above and reduce the oil recovery cost greatly, and can be widely used for tertiary oil recovery.

The invention relates to an active water oil displacement method used for low permeability reservoirs, in particular to a strengthened oil displacement method, and mainly solves the problem of low efficiency of oil displacement of the low permeability reservoirs in the prior art. According to the oil displacement method, a positive-negative system surfactant containing a 0.01-1.0wt% anionic-nonionic surfactant and a cationic surfactant in a molar ratio of 1:0.01-0.99 is injected into a water solution to form active water, dehydrated crude is enabled to be in contact with the active water under the condition of injected water at the oil displacement temperature of 40-100 DEG C with total mineralization (total dissolved solid) TDS more than 200mg/L, and crude in the core is displaced sufficiently. The problem is well solved, and the strengthened oil displacement method can be applied to tertiary recovery production of the low permeability reservoirs.

The invention provides a chemical cold-production method applicable to a medium and deep stratum low-permeability heavy oil reservoir. The method includes the first step of selecting a medium-deep low-permeability heavy oil reservoir, wherein the depth of the selected oil layer is 1500-2800m, the permeability of the selected oil layer is smaller than or equal to 50*10-3 square microns, the total thickness of the selected oil layer is larger than or equal to 3.0m, the total net thickness ratio of the selected oil layer is larger than or equal to 0.3, the porosity of the selected oil layer is larger than or equal to 0.10, and the permeability variation coefficient of the selected oil layer is small than or equal to 0.8, the second step of squeezing microemulsion viscosity reduction systems and liquid carbon dioxide into the selected oil layer alternately in a staged plugging mode, the third step of carrying out well shut-in, well soaking, well opening and blowout prevention, and the fourth step of continuing extracting oil through a downhole pump. The chemical cold-production method has the advantages that microemulsion can enable crude oil to be stripped to be oil droplets with hydrophilic surfaces, heavy oil spontaneously diffuses on the surface of system water solution, carbon dioxide has functions of reducing viscosity and increasing energy can enlarge the viscosity reduction radius of the microemulsion, the water recovery rate is improved, and the output and the recovery efficiency of the medium-deep low-permeability heavy oil through a synergistic effect are improved.

The invention relates to an oil-field largest swept volume chemical-flooding oil production method, which is applied to the technical field of oil production in oil fields. The method is applicable to all reservoirs which can be exploited by water flooding but are not exploited by water flooding. When oil is exploited, the self energy of the strata of a reservoir is first utilized to carry out flowing production or swabbing production; when an oil field adopting flowing production or swabbing production reaches the economic benefit limit of production, flowing production or swabbing production is ended, subsequent water-flooding production is not carried out any more, but chemical flooding injecting surfactant as main agent is directly adopted to intensify oil production. The method has the following advantages that: at the moment, the swept volume of the displacement of the chemical displacing fluid is the largest, which is best favorable for the exertion of the oil-washing effect ofthe surfactant, and thereby the yield of oil production can be increased to the max.

The invention relates to a betaine surfactant combination flooding composition and application thereof. The combination flooding composition comprises the following components in percentage by weight: 0.03-0.5% of betaine surfactant, 0.01-0.3% of nonionic surfactant, 0.0-0.3% of functional polymer surfactant, 0.0-0.5% of polymer, 0.0-1.5% of alkali and the balance of water. The functional polymer surfactant, polymer and alkali are not 0 at the same time. By using the cheaper betaine surfactant and integrating multiple mechanisms for enhancing the recovery rate, the surfactant combination flooding composition achieves good coordination between recovery rate enhancement effect and cost, can greatly enhance the oil recovery rate, and has economic effect of forced production in low-permeability reservoirs and reservoirs after polymer flooding.

The invention provides a method for improving the recovery ratio of a sensitive heavy oil reservoir. The method utilizes combined application of a high-temperature clay stabilizer, a sustained-release acidizing fluid system, an efficient oil-displacing agent and carbon dioxide in the development of the sensitive heavy oil reservoir to improve the single-well development effect and the recovery ratio of the sensitive heavy oil reservoir. The technical scheme is that the method comprises the steps of first utilizing the temperature-sensitive sustained-release acidizing fluid system to treat a polluted treat near-well-bore zone, then injecting the liquid carbon dioxide, utilizing the high-temperature clay stabilizer to protect an oil layer before steam injection and injecting a high-temperature oil-displacing agent system while the steam injection; then performing well shut-in for soaking and well opening for gushing and putting a pump into a well to perform continuous oil extraction. A field test shows that the oil-steam ratio of an average period of a vertical well reaches to 0.4, the oil-steam ratio of an average period of a horizontal well reaches to 0.6, and the periodic oil yield exceeds 1000t. A laboratory test shows that the final recovery ratio can reach to higher than 35% by adopting a process related to the method for improving the recovery ratio of the sensitive heavy oil reservoir.

The invention discloses a functional polymeric surfactant-reinforced betaine composite flooding system and a use thereof. The functional polymeric surfactant-reinforced betaine composite flooding system comprises, by weight, 0.05-0.5% of a polymer, 0.03-0.5% of a betaine surfactant, 0.01-0.3% of a functional polymeric surfactant, 0.01-0.3% of a nonionic surfactant, 0.0-1.5% of an alkali and the balance water. The functional polymeric surfactant-reinforced betaine composite flooding system utilizes combination of a plurality of oil flooding mechanisms, can greatly improve crude oil extraction ratio, can realize further oil extraction of oil reservoir subjected to polymer flooding, can greatly improve final oil extraction ratio of the oil reservoir and has effects better than those of the existing oil flooding system.

The invention belongs to the technical field of oil extraction, and particularly relates to a method for improving the oil reservoir recovery rate by integration of plugging, regulating and flooding,which comprises the following steps: 1, preparing composite gel, 2.5% of polyaluminum chloride, 4.5% of acrylamide, 0.9% of urea, 0.3% of ammonium persulfate and 0.3% of N, N-methylenebisacrylamide; 2, preparing a polymer microsphere/efficient oil displacement agent composite system, wherein a polymer microsphere material is hydrophobic association polymer gel, the microsphere concentration is 0.3%, the microsphere initial particle size is 2.7 [mu]m, the particle size median is 2.00 [mu]m, the particle size median is 18.92 [mu]m, and the expansion multiple is 10; and 3, injecting the compositegel into a dominant channel of an oil reservoir, waiting for gelling for 24 h, wherein the slug size is as follows: a main slug of 0.05 PV and a displacement slug of 0.025 PV; injecting the polymer microsphere/efficient oil displacement agent composite system into an oil reservoir from a water well, wherein the slug size is 0.1 PV; and carrying out subsequent water drive until the water content reaches 98%.

The invention discloses a rock core oil washing instrument comprising a main body. The main body is divided into an upper rock core chamber and a lower heating chamber, the rock core chamber and the heating chamber are partitioned by a seal partition, a plurality of steaming-condensing pipes are evenly distributed on the seal partition, an opening in the lower portion of every steaming-condensing pipe leads to the heating chamber, a gas outlet is formed in the upper portion of every steaming-condensing pipe, the seal partition is provided with a flood discharge pipe, the upper portion of the rock core chamber is connected with a condensing chamber through bolts, a rock sample basket is arranged in the rock core chamber, through holes are formed in the surface of the rock sample basket, the rock core chamber and the heating chamber are provided with liquid level meters, liquid in the heating chamber is heated by a heater, a ball valve is arranged at the outer bottom of the heating chamber, and a pressure gauge is externally connected with the rock core chamber. The rock core oil washing instrument has the advantages that cleaning requirements of geological rock cores can be met, oil washing efficiency can be improved, environmental protection and cyclic utilization of heat can be achieved, automation degree can be increased, use cost can be reduced, and temperature and pressure can be controlled automatically.