179 results about "Co2 flooding" patented technology

A carbon dioxide drive nuclear magnetic resonance imaging detection device belongs to the technical field of petroleum engineering and technology. The detection device comprises: a simulation core device which is arranged in a nuclear magnetic resonance imaging device; an injection system which sequentially injects formation water, crude oil and supercritical carbon oxide into the simulation core device; a measurement and control system which is employed to control pressure and temperature of the whole system; the nuclear magnetic resonance imaging device which is employed to detect and perform quantitative analysis on an image to be tested to obtain voidage and permeability of a porous medium, and saturation seepage parameters of the supercritical carbon oxide, the formation water and the crude oil; and an output measuring system which is employed to measure volumes of the carbon dioxide gas, the formation water and the crude oil. The detection device has a design pressure of 0-40MPa and design temperature of 0-180 DEG C, and can simulate experimental studies of different displacement schemes of the supercritical CO2 under a complex petroleum reservoir condition; the simulation core device is made of a brass material, which produces no magnetism, satisfies requirements for high pressure and strength, has a compact structure, can be recycled, is conveniently operated, simple and applicable in an experimentation.

The invention relates to a method for applying a gas-soluble surfactant to fluidity control of carbon dioxide oil displacement. The method comprises the following steps that the gas-soluble surfactant and supercritical carbon dioxide are evenly mixed according to the mass percent of 0.1%-1.5%, during mixing, pressure is 7-20MPa, temperature is from 40 DEG to 90 DEG C, then the mixture is poured into an oil reservoir. The gas-soluble surfactant is applied to carbon dioxide oil displacement for the first time, and the selected carbon dioxide oil displacement has a certain solubility in water and the supercritical carbon dioxide respectively. When the gas-soluble surfactants of the type are adopted for underground foaming to control the fluidity of the carbon dioxide, an aqueous phase carry underground injection method can be selected, and a supercritical carbon dioxide phase carry underground injection method also can be selected, so that the method for applying the gas-soluble surfactant to fluidity control of carbon dioxide oil displacement not only can be applied to fluidity control in the carbon dioxide oil displacement process of a low permeability reservoir, but also can be applied to fluidity control in the carbon dioxide oil displacement process of a conventional oil reservoir and a high permeability reservoir.

The invention provides an experimental device researching influence of formation water with a high degree of mineralization on CO2 flooding. The experiment device comprises a gas cylinder, a core holding unit and a gas-liquid separating device. The gas cylinder is connected to a piston container, the top of the piston container is connected to a back-pressure valve and a pressure gage, the bottom of the piston container is connected to an ISCO pump, the pressure gage is connected to the core holding unit, the outlet end of the core holding unit is connected to the gas-liquid separating device, and the gas-liquid separating device is connected to an upper computer through a gas flowmeter. The back-pressure valve is connected to the back-pressure valve, the side face of the core holding unit is connected to a circular pressing pump and the suction lift is high, the outlet of the core holding unit is connected to the back-pressure valve, and the back-pressure valve is connected to a back-pressure pump. The designed device can compare changes of core permeability after and before CO2 flooding, porosity, pore structures, contents of core minerals, surface shapes of the cores, masses of the core and the recovery rates and research influence of CO2 flooding on reservoir physical property and development parameters.

The invention relates to a multistage fracturing horizontal well inter-crack interval CO2 flooding oil extraction method. The method includes following steps: performing sectional fracturing on a horizontal well shaft to form multiple fracturing cracks perpendicular to the horizontal well shaft; mounting an oil pipe I and an oil pipe II in a casing in the horizontal well shaft, mounting flow controllers I at positions, corresponding to even-level cracks, of the oil pipe I, mounting flow controllers II at positions, corresponding to odd-level cracks, of the oil pipe II, and arranging a packer at a position, between the odd-level cracks and the even-level cracks, in an annular space of an oil jacket; at an initial production stage, utilizing natural energy for extraction until bottom hole pressure is lowered to bubble point pressure, and utilizing crack intervals for extraction, injecting CO2 into the oil pipe I, wherein CO2 enters the even-level cracks, and crude oil is output from the odd-level cracks and enters the oil pipe II at the same time; when oil yield is lower than economic limit yield, stopping injecting CO2. By the method, crude oil recovery rate can be increased substantially, and gas channeling can be inhibited effectively.

The invention provides an oil recovery method restraining channeling in the CO2 flooding process in a low-permeability fractured reservoir through two-stage channeling blocking so as to increase the oil recovery ratio. The two-stage channeling blocking technology comprises the steps that a strong adhesive system with a natural modified polymeric material as the main agent is injected and forms a high-strength adhesive through waiting on cement setting to block off a fracture; fatty amine serves as a channeling blocking agent to block off channeling, caused by a relatively high-permeability layer in a low-permeability matrix, of low-viscosity CO2. By means of the two-stage channeling blocking technology, channeling in the CO2 flooding process in the low-permeability fractured reservoir can be effectively controlled, the swept volume can be increased, and therefore the oil recovery ratio can be increased.

The invention provides a device and method for determining the change law of oil-water interfacial tension in a CO2 oil displacement process, belonging to the field of test methods used in oil and gas field development. The method comprises the steps of: firstly determining the oil-water interfacial tension under different pressures in the water flooding process; then with an oil deposit condition being unchanged, converting to CO2 flooding, then determining the oil-water interfacial tension under different pressures in the CO2 flooding process, and finally comparing the two determined oil-water interfacial tensions, thus obtaining the change law of the oil-water interfacial tension in the CO2 injection process. By using the method, the changing process of the oil-water interfacial tension in the CO2 injection process can be simulated under the oil deposit condition, and further the change law of the oil-water interfacial tension in the CO2 injection process is concluded, and data and theoretical support are supplied for the CO2 oil displacement process of an oil deposit; and according to the method, the process from water flooding to CO2 flooding is continuous, the oil deposit condition is unchanged, and the implementation situation of a real oil field can be better simulated.

The invention provides an experiment method for researching influence on CO2 flooding by highly-mineralized formation water. The experiment method includes the following steps that a slabbed core A and a slabbed core B are cut from the two ends of a rock core, the rock core is washed, dried and weighed, the rock core pore volume and the gas logging permeability are measured, the rock core is saturated, magnetic resonance imaging is detected, and flooding is carried out to obtain rock core water logging permeability; flooding is carried out, temperature and pressure are kept for placement, CO2 water and gas injection is conducted, the rock core is washed and dried, the mass, the pore volume and the gas logging permeability are measured, vacuumizing is carried out, the rock core is saturated, flooding is carried out to measure the rock core water logging permeability, and magnetic resonance imaging is conducted; a slabbed core C and a slabbed core D are cut from the two ends of the rock core, washed and dried, electron microscope scanning, surface element and rock mineral analysis are carried out on the slabbed core A, the slabbed core B, the slabbed core C and the slabbed core D, the steps 1-3 are repeated after replacing the rock core and changing the temperature and the pressure; data is collected. The influence on reservoir physical property and development parameter collection by CO2-water-rock interaction and CO2-formation water precipitation can be researched.

The invention relates to an adjustor for reducing the minimum miscible pressure of CO2 non-miscible flooding and an application method thereof and belongs to the technical field of enhancing the oil recovery by CO2 flooding in an oil field. The adjustor is prepared from benzene homologs and derivates, ether matters, an oil soluble surfactant and a foaming agent. The application method comprises the following steps: (1) before carrying out CO2 flooding, injecting the adjustor into a reservoir by virtue of an injection well; and then braising the well till the adjustor is fully contacted with crude oil and dissolves; and (2) continuously injecting CO2 into the injection well till the gas-oil ratio in an output well exceeds the dissolved gas oil ratio under a formation condition. The adjustor provided by the invention has the beneficial effects that the adjustor can generate foam with CO2 to control the fluidity; meanwhile, as the benzene homologs and derivates, ether matters and oil soluble surfactant dissolved mutually promote so as to reduce the interfacial tension between CO2 and crude oil, so that the minimum miscible pressure of CO2 flooding is reduced, and the oil recovery of the CO2 flooding is improved to a great extent.

The invention relates to the technical field of oil-gas field development and carbon dioxide underground storage, in particular to a device and a method for surveying a migration law of carbon dioxideduring carbon dioxide flooding and sequestration. The device comprises an injection system, a seal cavity clamping system and an information collection system; a formation condition is simulated inside the seal cavity clamping system, and an injection well and producing wells communicating with the bottom of a formation are arranged over the seal cavity clamping system; the injection system is connected with the seal cavity clamping system and injects a certain amount of carbon dioxide, and the producing wells are used for discharging crude oil to the outside; and the information collection system includes a gas detector and an information data processing computer, and the gas detector and the information data processing computer are in signal connection. The migration law of carbon dioxide can be simulated and obtained, and real-time plugging is performed when the diffusion range of carbon dioxide reaches a leakage threshold value; and a plugging technology is evaluated and has important significance in leakage prevention and sequestration of carbon dioxide in practical production.

The invention provides a fleeing proof agent for the carbon dioxide flooding of oil reservoirs with ultra-low permeability and the application of the fleeing proof agent. The invention is characterized in that: the main agent of the fleeing proof agent is the amine substance of organic compounds; the fleeing proof agent comprises at least one amine substance and a release agent; the release agent is the ethanol comprising a certain amount of water, a hydrocarbon substance or nitrogen; the release agent is used to prevent the chemical reaction caused by the premature contact between the amine and the carbon dioxide. The invention is suitable for the gas channeling inhibition during the carbon dioxide flooding process for oil reservoirs with ultra-low permeability. The invention has the advantages that: the fleeing proof agent mainly block the gas channeling channel by the salt precipitation generated by the reaction between the carbon dioxide and the amine; the generation time of the salt precipitation is controlled by the injection volume of the release agent; the swept volume displaced by the carbon dioxide is enlarged, and the improvement of the economic benefit of carbon dioxide flooding is favored.

The invention provides a substance balance method for predicting carbon dioxide flooding oil reservoir indexes. The substance balance method for predicting the carbon dioxide flooding oil reservoir indexes comprises the following steps of: 1, giving application conditions of a carbon dioxide flooding substance balance equation; 2, building a substance balance equation applicable to the carbon dioxide flooding; 3, storing oil reservoir parameters and determining a calculation parameter; 4, calculating the parameters of the corresponding time period, wherein the parameters of the corresponding time period include the oil yield and the gas injection volume; and 5, using the parameters obtained through the calculation in the fourth step to determine the carbon dioxide flooding oil reservoir indexes such as the injection-production ratio and the recovery percent. The substance balance method for predicting carbon dioxide flooding oil reservoir indexes has the advantages that the substance balance equation which considers the compressibility of the oil reservoir rock fluid and is applicable to the carbon dioxide flooding is built; an application method of the substance balance equation is given; and an effective method is provided for predicting the carbon dioxide flooding oil reservoir indexes.

The invention discloses a plugging agent for oil field gas driving, and the plugging agent is mainly applied to profile control and water plugging employing a carbon dioxide flooding well in an oil field. The plugging agent comprises the following components in percentage by weight: 0.2%-0.7% of a plugging agent tackifier for oil field gas driving, 0.2%-1.5% of a cross-linking agent and the balance of water. The plugging agent is prepared by the following steps: firstly, adding clear water to a liquid dispensing tank at the ratio, starting stirring, and evenly scattering the plugging agent tackifier for oil field gas driving; and stopping stirring, so as to prepare the plugging agent for use after a thickening agent is completely dissolved and dispersed. The cross-linking agent is added according to the actual requirement ratio during fracturing construction. The plugging agent is convenient to prepare, and large in gelling viscosity when used by matching with the cross-linking agent; gas escape is relatively well prevented; and the plugging agent can play a good role in profile control and water plugging by using the carbon dioxide flooding well.

The invention provides low-cost oil-based annulus protection fluid applicable to a CO2 flooding well and a preparation method thereof and belongs to the technical field of corrosion protection of an oil and gas well. A low-cost oil-based annulus protection fluid system applicable to the CO2 flooding well is prepared by compounding engine oil, a corrosion inhibitor, a bactericide, an oxygen removing agent, a density regulator and a surfactant. The annulus protection fluid is prepared from the following components in percentage by mass: 1 percent to 3 percent of a morpholine derivative compoundcorrosion inhibitor, 0.8 percent to 1.6 percent of halogenated hydantoin bactericide, 3 percent to 5 percent of the oxygen removing agent, 5 percent to 30 percent of an organic acid salt density regulator, 3 percent to 5 percent of a non-ionic type polyoxyethylene type surfactant and the balance of the engine oil. The oil-based annulus protection fluid provided by the invention has a very good protection effect on a shaft tubular column of the CO2 flooding well and has the advantages of good high-temperature stability, good low-temperature freezing resistance and long-period stability; meanwhile, the refrigeration engine oil is used as a dispersant, so that the low-cost oil-based annulus protection fluid has the advantages of low cost and the like.

The invention provides a compound type anti-gas-channeling agent for carbon-dioxide flooding. The compound type anti-gas-channeling agent for carbon-dioxide flooding is prepared from the following raw materials: polymer gel and precipitate base fluid; on the basis that the total mass of the polymer gel is 100%, the polymer gel is prepared from the following raw materials: 0.5-1% of polyacrylamide, 0.1-0.5% of an organic metal crosslinking agent, 0.5-2% of a resin crosslinking agent, 0.05-0.2% of a stabilizing agent and the balance of simulation formation water; on the basis that the total mass of the precipitate base fluid is 100%, the precipitate base fluid is prepared from the following raw materials: 2-15% of a precipitation solution and the balance of simulation formation water. The compound type anti-gas-channeling agent for carbon-dioxide flooding is good in anti-gas-channeling effect.

The invention provides a petroleum reservoir carbon dioxide miscible flooding pressure prediction method and device and relates to the technical field of petroleum reservoir exploitation. The method includes the steps that the basic parameters for predicting petroleum reservoir carbon dioxide miscible flooding pressure are obtained; the solubility parameter of petroleum is determined; petroleum reservoir initial reservoir pressure serves as the trial pressure value, the current trial pressure value and the carbon dioxide density at the petroleum reservoir temperature are determined, and the solubility parameter of the carbon dioxide is determined; the absolute value of the difference of the solubility parameter of the petroleum and the solubility parameter of the carbon dioxide is determined; if the error of the absolute value of the difference and the preset threshold value is smaller than the preset error value, the trial pressure value serves as the minimum petroleum reservoir carbon dioxide miscible flooding pressure; and if the error is larger than or equal to the preset error value, the trial pressure value is adjusted, the updated trial pressure value is formed, the current trial pressure value and the density of the carbon dioxide at the petroleum reservoir temperature are re-determined, and the solubility parameter of the carbon dioxide is re-determined till the error is smaller than the preset error value.

The invention discloses an experimental device for ultrasonically promoting gas in CO2 (Carbon Dioxide) drive produced liquid to desorb. The device comprises a high pressure gas tank which is connected with a visual solution absorbing reaction kettle connected with data acquisition recording equipment, and the bottom of the visual solution absorbing reaction kettle is connected with an ultrasonic generating system. According to the device, the de-compressive desorbing process of the CO2 drive produced liquid in a separator can be simulated in the presence of ultrasonic waves, an initial condition and a terminating condition of the experiment are likely to be controlled, the repeatability of experiment is good, the data measurement record is accurate, the combination of ultrasonic frequencies and power can be diversified, and the desorbing phenomenon is visual, therefore the dissolving characteristics, desorbing characteristics and the ultrasonic reinforced desorbing function of the CO2 in the drive produced liquid can be beneficially and deeply studied.

The invention discloses a carbon dioxide foam generating device for carbon dioxide drive. The carbon dioxide foam generating device comprises a carbon dioxide tank, a gas guide pipe, a check valve, afoam generating box, a foam generating liquid tank, a foam guide pipe, a first rotating rod, a first motor, a second rotating rod, a gas inlet pipe, a second turbine, an installing box, a single gear,an electric control valve, an exhaust pipe, a second motor, an annular heat conduction plate, an annular heating box, a second stirring blade, a shaft rod, a first turbine, a connecting rod, a refrigeration sheet, an annular rotating plate, a gear ring, a single-chip microcomputer, a control panel, a first stirring blade and a temperature sensor. Carbon dioxide foam can be better stirred when conveyed and is prevented from being liquefied, and therefore the foaming efficiency of the carbon dioxide foam is greatly improved; the temperature of the carbon dioxide foam can be better adjusted, thefoam quality is prevented from being influenced by the too high temperature difference, the carbon dioxide drive efficiency is greatly improved, and meanwhile practicability is enhanced.