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Method of oil pool development by horizontal wells with multiple hydraulic fracturing Method includes drilling of horizontal producers and injectors with parallel horizontal boreholes or selecting drilled wells, determination of the first direction for the maximum primary stress in the stratum δmax1, performing multiple hydraulic fracturing in horizontal boreholes of producers and injectors, injecting water through horizontal injectors and extracting the product through horizontal producers. At that at first multiple hydraulic fracturing is made in horizontal boreholes of the producers thus obtaining fractures in parallel to δmax1, water injection is made to horizontal injectors with temperature t equal to the current temperature of the stratum t, while the product is extracted through the horizontal producers. During the closest winter period water is cooled till temperature of (0.5-0.7) t and injected in the volume to be calculated as per the suggested formula, change in the maximum primary stress of the stratum δmax2 is recorded for bottomhole zone of the injector in result of cold water injection, multiple hydraulic fracturing is made in the horizontal borehole of the injector thus obtaining fractures in parallel to δmax2, thereupon injection of non-cooled water is started. |
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Method of oil pool development with hydraulic fracturing Method includes drilling of producers and injectors, making elements with the injector in the centre and producers around it or selecting drilled wells, determination of the first direction for the maximum primary stress in the stratum δmax1, performing hydraulic fracturing in producers, injecting water through injectors and extracting the product through producers. At that hydraulic fracturing is performed at first in the wells where displacement front from the injector is parallel to the direction of hydraulic fracturing, thus obtaining fractures in parallel to δmax1. Water is injected to injection wells with temperature equal to temperature of the stratum t, and the product is extracted through the producers. During the closest winter period water is cooled up to the temperature of (0.5-0.7)t and injected in the respective volume until inflow of cold water is fixed in the remaining wells without performed hydraulic fracturing, change in maximum primary stress of the stratum δmax2 is determined in the producers without performed hydraulic fracturing in result of cold water injection, hydraulic fracturing is made in the above producers thus obtaining fractures in parallel to δmax2, thereafter injection of non-cooled water is started. |
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Control method of oil pool development Method includes allocation of a pool area with wells intercoupled hydrodynamically, extraction of the product from producers with production rate analysis, injection of a displacement agent to injectors with definition of well interference contours and correction of the production rate for the producers. According to the invention production rate analysis and injection of a displacement agent to injectors is made on the basis of detected intercoupling with the respective injectors against their total production rate at actual operation at the allocated areas using archive databases from 1 year up to 20 years and current data for the whole optimisation period with increment of 1-3 months. By production rate control in the producers the volume of injection to the injectors is changed and redistributed considering impact of the respective producers and injectors. At that the total volume of injection is changed not more than per 10%. Regulation of the extraction modes from the producers includes increase in product extraction from wells with maintained or insignificantly increased water cut and reduction of extraction up to complete stoppage with fast product watering out. At that remaining reserves are worked out using the producing well stock with increase in total flow rate and reduction of total water cut of the product, and liquid movement flows are redistributed till the remaining reserves are worked out. |
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Method includes injection of working fluid through a long string with a packer to the lower object and extraction of reservoir fluid through a short string from the upper object. The long string is placed close to the well wall opposite the short string oriented to the mouth using a parallel anchor. Part of the long string below the parallel anchor is made of tubes of heat insulating material with diameter 1.25-1.52 times bigger than tubes upwards the parallel anchor. The axial packer is set at the end of the long string. The long string is tensioned till it adjoins the well wall. The short string has diameter 1.25 times bigger than diameter of the long string above the parallel anchor, and it is installed in the parallel anchor. Injection of the working fluid through the long string and extraction of reservoir fluid through the short string may be performed in periodical mode. |
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Method of oil deposit development by water and gas injection Method includes drilling of producers and injectors or selection of ready producers and injectors within the oil deposit site, injection of water and associated gas to injectors and withdrawal of the product through producers. In compliance with this invention, vertical wells drilling data are used for calculation of optimum injection parameters for water and gas using the hydrodynamic model. Injection is made by cycles consisting of three stages. At the first stage the producers are shut in, gas in injected in volume selected during their operation. At the second stage, with shut in producers, water injection is made till injection pressure increases 2 times in comparison with the initial value. At that the initial injection pressure is maintained within the range of Pi=(0.45…0.55)·Pr, where Pr is vertical rock pressure. Thereafter the third stage is started. Injection is stopped and producers are launched. Associated gas is collected to tanks for its further use at the first stage. When the reservoir pressure decreases per more than 20% from the initial value the cycle is repeated. At that at the first stage injection rate of the gas qq to each injector is determined by the analytic expression. In deposits with oil viscosity more than 50 mPa·s at the second stage water is injected with down temperature of 90°C at least. Gas and water are injected respectively at the first and second stages as for injectors. |
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Development method of oil deposit with horizontal wells Method includes drilling and infrastructure development of horizontal producers and injectors crossed in the structure plan, placement of horizontal injectors in the structure plan lower than horizontal producers, perforation of the wells in the productive part with different density, injection of the working fluid to injectors and extraction of the product through producers. According to the invention horizontal wells are placed in parallel to the deposit length and width. At that entry to the productive stratum of producers is placed along one side of the deposit while entry of injectors is placed along the other side perpendicular to the first one. Density of perforated holes at each section of the horizontal wells formed by crossing of producers and injectors in the structure plan is minimum at the cross points and it is increased towards the centre of each section. At the initial stage of development fresh water or water with suspended matters concentration not less than 50mg/l is injected till water cut is decreased in the well. Thereafter stratal or waste waters are injected. Perforation density at the cross points in increased towards the centre of each section on the basis of analytical state considering the well hydrodynamic efficiency against the nature of the horizontal hole opening, distance from the perforated interval up to the horizontal hole of the adjacent well and in-place permeability in the respective perforation interval. |
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Development method of fractured-porous types of reservoirs Method comprises drilling producers and injectors, injecting water via injectors and withdrawing product via producers. According to the invention water is injected at the initial stage of development. When one of producers is flooded by the injected water up to 95%, the injector is identified where water is broken. To the water injected to this injector ash is added; ash is represented by remains of burn solid fuel with particle size of 70 mcm and concentration of 50 mg/l at the most. When water cut in the producer decreases per 25% or more water without ash is injected. These cycles are made for all watered wells and repeated till water cut after injection of water with ash decreases less than 95%. |
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Development of low-permeability oil pools by horizontal wells with maintenance of seam pressure Proposed method comprises drilling of parallel production and injection horizontal wells combined with multiple hydraulic fracturing of the seam. Working fluid is injected in injection wells to withdraw the products from production wells. Note here that at least one production and one injection wells are drilled in seams with permeability not over 2 mD and distance between horizontal shafts of at least 50 m. Production wells are arranged at maximum oil saturation strata. Angle between the maximum main strain of the seam and direction of horizontal shafts of production and injection wells makes some 30-60 degrees. The number of N stages of multiple hydraulic fracturing is selected proceeding from the condition N=1+L/100, where L is the well horizontal shaft length to be rounded to a large integer. Total amount of horizontal wells is drilled so that specific initial geological oil store per one horizontal well makes at least 50 thou t. |
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Processing of fractured reservoir Proposed method comprises determination of pool fracturing or softening lines, construction of production and injection well with allowance of the pool fracturing, injection of displacing agent into injection wells and withdrawal of oil via production wells. In compliance with this invention, pool section is selected for development with oil-saturated depth of over 10 m preventing the quick watering of extracted oil. Location of softening nodes, intersection of softening lines, is defined. Vertical production wells are drilled in irregular spacing to get to softening nodes. Injection wells are located in compacted carbonate reservoirs with minimum and mean fracturing between several softening nodes at equal distance therefrom. |
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Development of fractured reservoirs Proposed method comprises determination of pool fracturing or softening lines, construction of production and injection wells with allowance for formation fracturing, injection of displacing agent in injection wells and oil withdrawal via production wells. In compliance with this invention, area of the 10 m-deep oil-saturated pool is selected whereat quick flooding of extracted oil with bottom water is ruled out. Location of softening nodes, an intersection of softening lines, is determined. Vertical production wells are drilled in irregular spacing to get to softening nodes or as lateral or lateral horizontal shafts with crossing of adjacent softening lines connected with softening nodes. Injection wells are located in compacted carbonate reservoirs with minimum and mean fracturing between several softening nodes at equal distance therefrom. |
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Development of minor oil deposits Proposed method comprises drilling of exploration wells, research, refining of deposit sizes, trial operation and construction of geological hydrodynamic model, additional pay drilling, oil extraction via production wells and injection of working agent via injection wells. In compliance with this invention, at drilling of exploration wells vertical test, exploration and operation wells are drilled so that they can be transformed for injection of working fluid. Conditional lines run through test and exploration wells and through exploration and operation wells make the angle of 30 to 180 degrees to ensure maximum coverage of the deposit by said wells. Drilling data thus obtained are used to construct a geological hydrodynamic model to define the length, operating parameters and number of operation wells provided that one horizontal well allows extraction of at least 25000 tons of recoverable oil deposits. Horizontal operation wells are bored. Horizontal shafts of operation wells are located at 45 to 90 degrees to larger axis of the deposit and at 30-60 degrees to direction of prevailing fracturing and at equal distance from vertical wells. During trial operation, vertical wells are changed over to injection of working fluid after drilling of horizontal operation wells. |
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Proposed method comprises drilling or selection of drilled production and injection wells at oil deposit section. Lateral horizontal shafts or horizontal injection wells are drilled. Water-gas mix consisting of water and associated oil gas is injected via vertical injection wells, hot water is injected via horizontal injection wells or via lateral horizontal shafts and extraction of products via production wells. In compliance with this invention, vertical wells drilling data are used for calculation of optimum injection parameters using the thermal hydrodynamic model. Said horizontal injection wells or lateral horizontal shafts are drilled parallel with multi-face wells or horizontal production wells with spacing between shafts making at least 150 m. Said horizontal injection wells or lateral horizontal shafts are equipped downhole heaters to force hot water with temperature 95°C at well mouth and at injection pressure of (0.45-0.85) Pr, where Pr is vertical rock pressure. In every vertical injection well, injected is water-gas mix at flow rate of Qg=Vg/N+Qw, m3/day, where Vg is the volume of extracted associated oil gas per day, m3; N is the number of vertical injection wells; Qw is flow rate of water injected in vertical injection wells for 100% compensation for extraction for injection, m3/day. |
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Control method of oil pool development Method includes allocation of a pool area with wells intercoupled hydrodynamically, extraction of the product from producers with production rate analysis, injection of a displacement agent to injectors with definition of well interference contours and correction of the production rate for the producers. According to the invention production rate analysis and injection of a displacement agent to injectors is made on the basis of detected intercoupling with the respective producers against their total production rate at actual operation at the allocated areas using archive databases and current data for the whole optimisation period with increment of 1-3 months. By production rate control in the producers the volume of injection to the injectors is changed and redistributed considering impact of the respective producers and injectors. At that the total volume of injection is changed not more than per 10%. Remaining reserves are worked out using the available stock of wells with increase of total production rate of the producers and decrease in water cut or maintenance of this value at the current level. |
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Method for development of separate small oil lenses While developing separate small oil lenses penetrated by a single well extraction of the formation fluid is alternated with injection of a displacement agent. Injection of a displacement agent is made at pressure that does not exceed breakdown pressure determined against geological and physical parameters of the lens until intake reduces per 50% in comparison with the initial value. Fluid extraction is made till the oil production rate decreases per 20-60% in comparison with the initial value. At that injection periods at the initial stage are made through equal time intervals until formation pressure reaches the initial value. Extraction periods at the initial stage are also made in equal time intervals until formation pressure reduces up to 80-90% of bubble point pressure. At that the initial development stage is considered completed when the initial oil production rate decreases in the second and next extraction cycles up to 30-60% of the initial oil production rate in the first cycle. |
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Reservoir pressure maintenance system Reservoir pressure maintenance system includes pumps, water distribution devices with flow meters, flow controllers, water passages connecting water distribution devices to branch lines coming to injectors with different intake and grouped as per the water passages in compliance with an intake and water injection pressure. According to the invention the water passages with connected injectors with high or medium intake are coupled to the collector of the water distribution device through a spring-type flow controller with a calibrated inlet port at a movable element of the flow controller that closes output channels with potential maintenance of the required fluid flow. Branch lines of injectors with high intake connected with branch lines of injectors with medium intake are coupled to the same water passage and equipped additionally with the similar spring-type flow controllers with the calibrated inlet port that ensures required fluid flow for the respective well considering interaction with the flow controller installed at the respective water passage. At that the pump discharge line connecting it to the water distribution device is equipped with a pressure sensor while the pump is equipped with a variable frequency drive connected functionally to the pressure sensor. |
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Method for development of oil pool section Method lies in drilling of a deposit by vertical and/or directional injection wells and producing wells with crossed and mutually perpendicular boreholes, injection of a working fluid through the vertical and/or directional injection wells and oil extraction through the producing horizontal wells. In two oil-saturated interlayers with matching structural geometry, horizontal boreholes of the producers are made with a length 4 times bigger than the distance between the producers and injectors so that the horizontal boreholes form the grid at cross-sections. 1 or 2 vertical and/or inclined injectors are placed to the centre of each cell. At that a row of parallel horizontal boreholes of the producers is made in one of the oil-saturated interlayers while the other row of parallel horizontal boreholes of the producers is made perpendicular to the first row in the other oil-saturated interlayer in order to create perpendicular filtration flows of one interlayer in regard to the other. The minimum distance between the horizontal boreholes at their cross points in structural geometry is 0.5 m and water-swell packers are envisaged to cut off points of the working fluid breakdown. |
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Method of development of oil-and-gas deposits with bottom water Method of development of oil-and-gas deposits with bottom water includes primary gas cap blowdown by gas wells and withdrawal of at least part of gas with subsequent joint development of gas cap and oil rim by opening-up of last with producing and injection wells, injection of displacement agent into the oil part of the deposit and oil withdrawal. According to the invention, at the beginning of gas withdrawal from the gas cap, withdrawal and pass-by of bottom water into the gas cap are performed. Bottom water is moved along the gas and oil contact and a barrier is created on the gas and oil contact in order to reduce oil cross-flow into the gas cap and embed bottom water in the oil part of the deposit. At that, volumes of gas withdrawal and pass-by water are controlled making sure that gas and oil contact is kept almost immovable. |
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Method of extraction of oil and other formation fluids from reservoir (versions) Invention group is related to the methods of increase of extraction of heavy or viscous crude oil from an underground reservoir and in variants of its fulfilment is especially related to operations of cold extraction from such reservoir. Substance claim: the method involves oil-bearing reservoir rock and has at least one development well and at least one injection well. The method provides for carrying out secondary recovery operations with the use of displacing fluid; at that, density of extracted oil is within ≤30° API, and the method includes the following operations: (a) overinjection of displacing fluid into reservoir rock with Voidage Replacement Ratio (VRR) from 0.95 to 1.11 until Water-Oil Ratio (WOR) of formed fluids is at least 0.25; and (b) underinjection of displacing fluid into reservoir rock with VRR<0.95 until Gas-Oil Ratio (GOR) of formed fluids is at least twice higher of GOR with dissolved gas of initial oil recovered from a well; at that, during water injection, accumulated VRR is kept within 0.6 to 1.25. |
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Development method of non-homogeneous oil deposit Development method of non-homogeneous oil deposit includes drilling as per any famous pattern of vertical, horizontal or directional wells. Borders of zones with various permeability are determined. The well pattern is compacted up to the value of 4 ha per a well. A displacement fluid is injected to each zone through injectors and the product is recovered from the formation in each zone through producers. At that zones with different permeability are divided into low permeable, medium permeable and high permeable. Compaction of the well pattern is made only in low permeable zones. At that the ratio of injectors and producers is selected as at least 1:5 in the high permeable zones, from 1:3 up to 1:5 in the medium permeable zones and from 1:1 up to 1:3 in the low permeable zones. When the flow rate at one zone becomes lower than the commercial production hydrofracturing is made at this site. Then permeability is determined at this site and it is referred to the respective zone with determination of the respective number of injectors and producers. |
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Device for dual injection operation to two formations of same well (versions) Device is mounted at the flow string and contains a hanger with two packers. In the hanger cavity there are at least two collars with a hermetical cup installed in collars; the cup is made with a thrust to a butt end protrusion of the hanger and this protrusion has longitudinal channels that form an annular space. In the cup wall at both sides of the lower collar there are two units with calibrated flow sections communicating the cup cavity with the upper well formation through the upper union, the annular space between collars and windows made in the hanger wall at one side and with the lower well formation through the lower union, the annular space below the collars and longitudinal channels of the butt end protrusion at the other side. |
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Method for production of soft water for injection into bed Invention relates to production of soft water for injection into bed. The method includes: (a) production of soft water by means of (i) delivery of source water having total dissolved-solids content up to 15000 mg/l and polyvalent cations content more than 40 mg/l to the filter containing a layer of cation-exchange resin in polyvalent cation form; (ii) passage of source water through the layer of cation-exchange resin; (iii) output of soft water for injection from the filter, at that polyvalent cations content in water is up to 40 mg/l; (b) regeneration of cation-exchange resin by means of (i) delivery of regenerant solution to the filter, at that the regenerant solution is represented by natural water with high content of salts, high concentration of monovalent and polyvalent cations so that the softening limit for source water is equal up to 40 mg/l of polyvalent cations where the softening limit is defined as the softening coefficient multiplied by concentration of polyvalent cations in source water (mg/l) and where the softening coefficient is calculated in the following way: (molar concentration of monovalent cations in source water)2/(molar concentration of polyvalent cations in source water) : (molar concentration of monovalent cations in the regenerant solution)2/(molar concentration of polyvalent cations in the regenerant solution). |
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Procedure for development of deposit of oil in carbonate collectors Penetration of productive strata and subjacent water-bearing beds is made by injectors with subsequent construction and casing perforation, penetration of productive strata by producers with subsequent construction and penetration of the productive stratum, water-flooding of the productive stratum by downhole pumping in injectors from water-bearing beds to the oil-bearing bed, product extraction from the productive stratum through producers. According to the invention water-flooding of the productive stratum is made under permanent pressure with sequential operational delays of injectors less than 4 days. At that pressure compensation by water-flooding at operational delay of the injectors is made due to the closest injectors. In the process of oil production rate decrease, at water-flooding from water-bearing beds pressure compensation is made by water and/or reagents pumping from the mouths of the injectors. |
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Oil deposit development method Direction of reservoir-scale fractures is determined, the formation is drilled by vertical and/or inclined wells and downhole splitters as per square grid pattern and five-spot system is formed with drilling in the centre and corners of the system elements by vertical and/or inclined wells and drilling between the central and corner wells in the development pattern of downhole producing splitter with rounded borehole ending, and working fluid injection through injection wells and product recovery through producing wells. If producing wells are flooded the water-flooding interval is identified and water-flooded intervals are isolated. According to the invention, before drilling of the formation sections with total oil-filled thickness of more than 6 m are determined in carbonate reservoirs and/or sections with net oil thickness of 2 m at least in oil zone and at least 4 m in water-oil zone in terrigenous reservoirs. At these sections before drilling of downhole producing splitter direction of reservoir-scale fractures is specified. The downhole splitter is made with semi-ellipse shape which major axis is directed at angle of 30-60° to direction of reservoir-scale fractures with ratio of minor semi-axis to the major semi-axis equal to 0.1-0.8. At that boreholes of producing downhole splitters are made ascending with minimum distance in the lower part up to water-oil contact of 4 m for carbonate reservoirs and 2 m for terrigenous reservoirs and in the upper part with minimum distance of 1 m up to the roof of productive strata. |
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Oil deposit development method Method lies in drilling of a deposit by vertical and/or directional injection wells and horizontal producing wells with crossed and mutually perpendicular boreholes, pumping of the working fluid through vertical and/or vertical and/or directional injection wells and oil extraction through producing horizontal wells. According to the invention, producing horizontal wells should be longer than 4 times of the distance between the producing and injection wells so that horizontal producing wells open the lower interlayers at the borehole beginning and ending, and the upper interlayers in the borehole middle part. In perpendicular direction horizontal producing wells open the upper interlayers at the borehole beginning and ending, and the lower interlayers in the borehole middle part. At that horizontal producing wells form a mesh with location of 1-3 vertical and/or directional injection wells in the centre of each cell. At that minimum distance between horizontal producing well in vertical plane is equal to 1 m. To cut off point of working fluid breakthrough to horizontal producing wells water-swellable packers are installed. |
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Oil deposit development method According to the method direction of reservoir-scale fractures is determined, drilling of the deposit by producing and injection wells considering direction of natural fracturing of the deposit, injection of working fluid to the injection wells and product recovery from the producing wells are carried out. Horizontal wells are used. Wells are used as elements of square grid pattern. One side of the square grid is placed along the fracturing direction. Horizontal boreholes of producing wells are placed in parallel to each other in staggered arrangement from the centre of one element of square grid pattern up to the centre of the neighbouring element in the grid placed corner-wise, near the roof of the oil-filled formation. In each producing well, in the productive formation, two water-swellable packers are placed, thus dividing the horizontal borehole into three equal parts. Horizontal boreholes of injection wells are placed in the centre of elements between two parallel neighbouring producing wells and made near water-oil contact or the bottom of the oil-filled formation. Producing and injection wells are made with a certain length of their horizontal boreholes to be determined as per the certain analytical expression. |
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Oil deposit development method According to the method direction of reservoir-scale fractures is determined, development elements are formed by drilling of horizontal injection wells as per square grid pattern with parallel placement of boreholes and producing downhole splitters with rounded bottomhole ending which are placed around the borehole of each horizontal well. Pumping of working agent is done through injection wells and recovery of products through multi-hole producing wells. When the latter are water flooded water-flooding intervals are identified and isolated. According to the invention a downhole splitter is made in the semi-ellipse shape which major axis is directed at the angle of 30-60° towards direction of fractures while ratio of the minor semi-axis of the ellipse b/2 towards major semi-axis a/2 is equal to 0.1-0.8. At that boreholes of a downhole splitter have length of (0.6-0.8)·a each in productive part of the stratum and water-swellable packers are installed at them at each 50-250m. The boreholes are placed near the roof of the productive stratum at distance of 0.5 m at least and less than 2 m from the roof. The horizontal injection well is placed in plane along the ellipse major axis of a producing downhole splitter with length of (0,3-0,6)·a of its horizontal part in the productive stratum, at water-oil contact or the bottom of oil-filled formation in profile at distance of 0.2 m at least and less than 1m from it. |
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Device for pumping gas-liquid mixture to formation Invention pertains to oil industry and can be used in system of out-contour and contour waterflooding during development of oil deposit with maintenance of formation pressure. The concept of the invention is as follows: device contains inner pipe string equipped with chamber for fluid and gas receipt and outer pipe string, encapsulated assembly. At that chamber for fluid and gas receipt communicates with tubing-casing annulus above the encapsulated assembly; it is made as low-pressure chamber of jet pump with ejector installed at the jet pump input, while it output is communicated with inner tubing string. At that delivery of gas is envisaged to tubing-casing annulus with possibility of its suction to low-pressure chamber of the jet pump. Encapsulated assembly is made as packer and installed in the well being a part of inner tubing string above the formation. Beyond the packer and opposite low-pressure chamber of the jet pump inside the inner tubing string there are through radial grooves for gas delivery. Outer piping string is equipped from below with ejector telescoped into the inner piping string at the input of low-pressure chamber of the jet pump with potential axial displacement in regard to inner piping string and regulation of flow passage of through radial grooves with possibility of their sealed cut-off. At that input of the jet pump is communicated with the outer piping string. Below the jet pump output the inner piping string is equipped with diaphragms with the central slotted openings. Each slotted opening of the following diaphragm is shifted per angle of 15-20° towards clockwise or anticlockwise direction. Below diaphragm inside the inner piping string there's tubular smoothing sleeve for liquid-gas mixture. |
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Method for recovery of residual oil reserves Invention pertains to oil producing industry and can be used at final stage of oil deposit developments with use of contour waterflooding. The concept of the invention is as follows: method includes contour waterflooding of oil deposit with use of injection and production wells. The most successful well is selected among production wells. Oil recovery coefficient and water cut by weight is checked for this well. When water cut by weight reaches its limit value and oil production is stopped hydrocarbon gas is pumped in preset volume to the above well. By hydrocarbon gas water is displaced from annular space of the most successful well and drainage area of oil strata and by water pumped to neighbouring injection wells impact is made on neighbouring injection wells. At that after hydrocarbon gas pumping the most successful production well is switched to production of oil-gas mixture. When water cut by weight reaches its limit value in other production wells hydrocarbon gas is pumped to them also. |
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Development method of oil fringe in carbonate reservoir of complex structure Method involves drilling of injection and horizontal production wells, arrangement of maintenance of formation pressure by water pumping, according to water flooding and gassing of products of production wells - drilling of side horizontal shafts at different levels within oil-saturated thickness as per analysis results of recovery of reserves and hydrodynamic simulation, as well as periodic operation of production wells. According to the invention, based on 3D observation well testing there determined is anisotropy of a productive reservoir in three-dimensional space - the main permeability directions. Both injection and production wells are constructed in the form of horizontal ones. With that, horizontal shafts of production wells are made in middle part of the oil-saturated thickness, and horizontal shafts of injection wells near gas and oil contact (GOC). Injection and production horizontal shafts are arranged parallel to each other as per a mixed single-row pattern so that distance between production shafts in a row can correspond to position of injection shafts in adjacent rows. Injection wells are operated in a periodic mode so that production wells stand idle during water pumping periods and accumulation of elastic energy margin occurs in the formation. Production wells are put into operation during downtime of injection wells. Duration of production and injection periods is chosen at the interval of 1-3 months based on the fact that formation pressure on GOC level in the area of production wells can exceed initial formation pressure by a depression value at operation of production wells plus 3-5 atm, and its reduction beyond the production periods can correspond to achievement of the initial formation pressure level. |
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Oil deposit development method Invention relates to the oil and gas industry, it can be used for development of oil deposits confined to the dome-shaped highs and at the final stage of deposits development. The concept of the invention is as follows: the method includes drilling of injection and producing wells, oil extraction through producing wells, surveying and determination of sections with dome-shaped highs exceeding actual elevations of the stratum, pumping of waterproofing sealant to wells, use of remaining wells located in direct vicinity from dome-shaped highs related hydrodynamically to producing wells within limits of this producing stratum and flooded completely in production process and used as injection wells to which operating fluid is pumped. According to the invention surveying and determination of sections with dome-shaped highs is made by temperature logging and determination of closed areas with temperature of 30-38°C corresponding to dome-shaped highs. Pumping of waterproofing sealant is made to wells located in cavities and completely flooded wells by suppression of the stratum in order to isolate water influx partially to dome-shaped highs from flooded areas. Branch or horizontal holes are made from these wells to penetrate stratum in the area of dome-shaped highs with further use of such holes as producers. |
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Method of oil deposit development using flooding Injection wells and horizontal extracting wells are drilled, heat carrier is injected via injection wells and oil is extracted through production wells. Horizontal well is drilled above the water-oil surface (WOS) while vertical well is drilled at least 50 m from horizontal well bottom. Pool is exposed another time in vertical well above and below horizontal well. Pipe string is downed in injection well to set packer in place between openings. Displacement agent is injected via top opening and pipe space while bottom opening - via pipe string. |
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System for heavy oil and natural bitumen deposit arrangement (versions) According to the 1st version the system includes fresh water source with fresh water pipeline, productive wells connected via product pipeline to oil preparation station equipped with marketable oil pipeline and pipeline of concurrently extracted water, connected to the waste treatment facilities that are connected to injection wells via fresh water pipeline, cluster pump station and water conduit fitted with corrosion inhibitor dosing unit. Well product pipeline is equipped with de-emulsifying agent dosing unit, waste treatment facilities are fitted with trapped oil pipeline for its return to oil preparation station, additionally equipped with product heating system with fuel gas pipeline and associated petroleum gas pipeline, and second purified water pipeline connected to water preparation unit for supply of concurrently extracted water to fine purification at oil extraction volume more than 10% from design maximum volume of oil extraction with purified water pipeline disconnection. Note that water preparation unit is connected to fresh water pipeline for its fine treatment for provision of steam generator by necessary water volume, as well as to cluster pumping station via brine pipeline and finely treated water pipeline with steam generator that is for water heating is connected to fuel gas pipeline and via steam pipe it is connected to the steam-injection wells. According to the 2nd version productive wells are connected via well product pipeline and booster pump station to oil preparation unit. |
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Method for inter-well fluid pumping Method includes packer installation above the production well bed, oil-water emulsion extraction from below-packer space by pump, descended at tube string, emulsion separation to oil and water in down-hole conditions, oil extraction from top part of above-packer annular space to oil pipeline, extraction of formation water and its pumping via water pipeline through injection wells into oil bed with undeveloped oil resources. Pump operation is provided in constant mode, oil-water emulsion is supplied through radial holes in tube string into above-packer annular space, where oil-water emulsion is separated. Water is extracted from above-packer annular space via subsidiary tube, the inlet of which is located below the level of water-oil contact, and its outlet is connected to the water pipeline fitted with flow metre. Oil extraction is additionally performed from tube string into oil pipeline, which is fitted with flow regulator and is connected to the subsidiary tube via bypass line, connected to the oil pipeline after flow regulator for water discharging into it at water pipeline repair works. |
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Method for maintaining formation pressure and device for its implementation Invention includes pumping of cluster pumping station fluid equipped with inlet and discharge water conduit through comb unit and injection wells into the formation in cyclic mode with regular stop of cluster pumping station operation. In the period of low outside temperatures at cluster pumping station stop there performed is a cluster controller adjusted by flow direction and volume fluid discharge from injection wells with close reservoir properties through discharge water conduit and bypass line into inlet water conduit or process tank. Fluid discharge volume is made with provision of multiple replacement of water in wellhead zones of injection wells. Device includes cluster pump station with inlet and discharge water conduits with flow metre, comb unit, connected to discharge water conduit of cluster pump station and water conduits of injection wells fitted with shut-off valves, and cluster controller connected to shut-off valves control units. Note that inlet water conduit and discharge water conduit between flow metre and cluster pumping station are connected via bypass line to adjusted by hydraulic resistance, equipped with process tank and shut-off-control valves made in the form of adjustable valve gates mounted capable of opening and closing of cross-flows from bypass line into inlet water conduit or process tank, as well as for closing bypass line at switching on, cluster pumping station. Note that the flow metre is connected to the communication channel about flow direction and fluid volume with cluster controller. |
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Water flooding method of oil deposits Method involves water pumping to a productive formation with simultaneous wave action. According to the invention, at development of floating oil deposits with production wells with horizontal shafts crossing definitely oriented vertical planes of fracturing, injection horizontal wells are located at the level of oil-water contact (OWC) or below it in water-bearing parts of the formation. With that, horizontal shafts of injection wells intersect the planes of vertical fracturing as production wells. Temporary shutters or liquid filtration controls are installed in production wells at fracturing intervals, and wave emitters at those intervals are installed in injection wells perforated at fracturing intervals. Uniform lifting of OWC with displacement of oil to horizontal shafts of production wells is provided by means of wave action. |
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Oil-well sucker-rod pumping unit for water pumping to stratum Oil-well sucker-rod pumping unit for water pumping to stratum includes packer installed upwards stratum, tubing string with pressure control valves and suction valves. Plunger pump with cylinder run-in at tubing-string is installed upwards valves. Suction valve is connected to space over the packer. Rod stripper is equipped with lubrication tank. Tubular annulus of the well is connected to water supply pipeline. Plunger is equipped additionally with device for forced downstroke. Downwards pressure control valve there's an auxiliary pressure control valve connected to space below the packer and output of this valve is done through isolating device. Device for forced downstroke of the piston can be made as loads or pneumatic accumulator connected to piston. Working cavity of pneumatic accumulator is the upper part of tubing string. Technical results provides expanding of application scope of the unit in injection wells with pumping under high pressure, improving operation reliability due to improving operation reliability of suction and pressure control valves. |
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Development method of oil deposits using formation hydraulic fracturing Method involves construction of injection and production wells, carrying-out of directional hydraulic fracturings so that hydraulic connection is provided, pumping of displacement agent to injection wells so that uniform front of high pressure is provided in rows of injection wells, and takeoff of fluid from production wells. With that, directional hydraulic fracturings are performed only in rows of injection wells. In production wells there made is an analysis of the product flooding rate, as per which flooding maps are built and configuration of front of oil displacement with water is determined. Besides, in different injection wells arranged in rows there changed are volumes of pumped displacement agent to provide uniform high-pressure front. |
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System of cluster water pumping to formation System of cluster water pumping to a formation includes a cluster pump station, a unit of a comb with gate valves, water conduits, gate valves arranged in a wellhead zone of injection wells, flow metres installed on the comb unit and/or in the wellhead zone of injection wells, the operation of which is provided at different working pressures with stops of the cluster pump station, a cluster controller with an information transfer channel from flow metres to the cluster controller, which has the possibility of opening and closing gate valves on the unit of combs and/or gate valves arranged in the wellhead zone of injection wells. According to the invention, cluster controller is equipped with a programmed interval timer having the possibility of sending opening or closing signals of gate valves to exclude freezing in a water conduit at minimum water flow velocity at stop of cluster pump station with the interval and duration of the opening, which are determined by empirical method depending on ambient temperature, diameter of water conduits, their heat insulation and composition of liquid in them for periodic pumping of one to three water volumes in the same water conduit. |
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Development method of oil deposit by water-flooding At development of an oil deposit by means of thermal water-flooding, inter-well pumping of formation water is performed from a below-lying formation to an above-lying productive formation and extraction of formation product is performed through production wells from productive formation. At inter-well pumping, water is extracted from the formation with temperature exceeding the productive formation temperature not less than by 20°C and with mineralisation of formation water, which is higher than mineralisation of water in productive formation not less than by 56 g/l; inter-well pumping is started at oil development stage, when formation pressure is decreased, and development is performed in formation pressure rise mode. Injection is performed in a cyclic mode. |
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Oil deposit development method During development of oil deposit the oil is extracted through production wells and working agent is pumped through injection wells. Production wells operated by bottom-hole pumps are changed over from operation conditions with constant extraction to operation conditions with constant bottom-hole pressure. Injection wells with non-express circulation behind the string or crossflows are defined. The defined injection wells are started for pumping in periodic mode with discrete water flow to a formation with variation from maximum possible flow to 0. Duration of operation of production wells changed over to operation conditions with constant bottom-hole pressure is controlled. At increase of duration of operation of production wells, injection rate is determined as per increasing formation pressure. At positive injection rate injection wells with non-express circulation behind the string or crossflows are put into operation without any repair, and production wells are continued to be operated under operation conditions with constant bottom-hole pressure. |
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Method of oil filed development Method involves oil sampling through producer wells and working agent pumping through pressure wells. According to the invention, the formation parameters are specified. For this purpose, the formations having ±20% equal porosity, gross sand, clay content and net thickness are specified in the interwell space as shown by current oil saturation charts or according to seismic exploration findings. The non-draining sites, stagnation zones and deposit course of the formations having the same characteristics are detected. A model of oil field development is changed. For this purpose, producer and pressure wells are further drilled on the formations for self-management, or the existing producer and pressure wells on the formations are further perforated, while those are preferentially the formations that are developed. |
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Method for controlling multimachine complex of reservoir pressure maintenance system Method implies drawing base head-capacity and energy curves for main and charging pumps and further on while in service by comparing continuously the head-capacity and energy curves to the reference for all the pumps of all the cluster pump stations (CPS) parallel-working for high-pressure water conduit system; that is followed by specifying an optimal number of simultaneous running main pumps with their head-capacity and energy curves to be matched within an optimal efficiency by changing a rotation frequency of their electric drives thereby avoiding throttle elements to be used. Additionally, an input and output pumpage temperature is measured, and a rotation frequency of the electric drives of the low-pressure charging pumps is adjusted herewith controlling specific energy consumption for all the main pumps. If the hydraulic and energy values appear to fall outside the limits of critical values for any main pump of all the parallel working CPS to be switched to a standby pump the technical characteristics of which enable matching the head-capacity curves of the main pumps within the optimal efficiency. |
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Method for cluster pumping of water into bed under negative temperatures Method includes water pumping with a cluster pump station via a valve manifold with gate valves along water conduits, through gate valves installed in a wellhead zone of injection wells, into injection wells under different working pressures with stops of the cluster pump station. Previously donor wells are detected, which pour water as pumping is stopped, and wells that receive water. For the period of shutdown of the cluster pump station the gate valves are closed at the valve manifold and/or in the wellhead zone of injection wells, and valves are periodically opened as temperature is achieved in the water conduit, which is 1-4°C higher than the temperature of freezing of the pumped water. Water in the water conduit of the wellhead zone of the injection well is substituted as water flows from donor wells into other wells in amount from one to three volumes of the water conduit for every opening of the gate valve. Before scheduled shutdown of the pump of the cluster pump station pumping is done only into detected injection donor wells. |
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Method to develop multizone oil reservoir Method includes downhole pumping of water from an underlying water-bearing bed into an overlying payout bed along an injection well and oil withdrawal from the payout bed via a producing well, which is hydrodynamically connected to the injection well. In accordance with the invention, a device is installed in the interval of the producing bed of the producing well for downhole separation of oil and water with the possibility to lift oil to the surface and discharge of water into the nearest underlying water-bearing bed and/or abandoned oil bed in the cut. Downhole pumping of water in the injection well from the underlying water-bearing bed and/or abandoned oil bed into the producing bed is carried out with the help of a pump, efficiency of which is accepted as not more than the intake of the producing bed, the injection well head is sealed, and the pump is put into operation. As water head reduces at the pump inlet in the injection well below a certain value, the pump is stopped, and the device for downhole separation of oil and water in the producing wall is put in operation. As water head increases at the pump inlet in the injection well above a certain value, the pump is put in operation, and the device for downhole separation of oil and water in the producing wall is stopped. If hydrodynamic connection between producing and injection wells deteriorates, operating equipment is withdrawn, hydraulic rupture of the producing and/or water-bearing beds is done. Afterwards operating equipment is again lowered, and development of the multizone oil reservoir is continued. |
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Development method of oil deposit in fractured reservoirs Method involves arrangement of production and injection wells, pumping of displacement liquid through injection wells and extraction of the product through production wells. The first injection well is developed for pumping of displacement liquid with development of interval of oil-water contact (OWC) of the formation. Extraction of the product is performed from production wells with developed oil-saturated intervals of the formation, which envelop it. At that cyclic pumping of displacement liquid is performed to the first injection well with 100-200% of compensation of product extraction from production wells enveloping it. Then, after flooding in fractures of one of production wells enveloping the first injection well, isolation of the open oil-saturated interval of the formation in the same well is performed with development in it of interval of OWC of the formation and with its being changed over to the second injection well for pumping of displacement liquid with 100-200% compensation of the product extraction from production wells enveloping it after flooding in fractures of one of the production wells enveloping it. After flooding in fractures of one of production wells enveloping the second injection well, isolation of the open oil-saturated interval of the formation in the same well is performed with development in it of interval of OWC of the formation and with its being changed over to the third injection well. Gradually, as fractures are being developed, a row of injection wells is created on the oil deposit, to which displacement liquid is pumped. Periodically polyacrylamide bank is pumped into the injection wells during stops in displacement liquid pumping. When products are flooded per more than 85% in each production well enveloping the injection well, open interval of OWC in this injection well is isolated and horizontal offshoots are drilled from it in the oil-saturated interval perpendicular to direction of fractures development and this well is transferred to product recovery. |
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Oil deposit development method Method involves delivery of water-gas mixture to oil deposit through an injection well; the mixture is prepared at the mouth of the injection well by means of a mixer and then delivered to the mixer under pressure of water and gas. According to the invention before delivery of gas stream light hydrocarbon fractions, foe example, oil, gas condensate, associated gas or a mixture of low-pressure gas with fractions of hydrocarbons C2+higher are input into the mixer by means of an ejector. At that mixing of high-pressure gas with a stream of gas having high concentration of hydrocarbon fractions C2+higher is carried out by means of an ejector installed in the gas well in production tubing over the roof of high-pressure gas formation. The stream of gas from high-pressure gas formation in drill string - borehole annulus is isolated by means of an isolating packer from the stream of low-pressure gas and delivered to high-pressure nozzle of the ejector. At that the stream of low-pressure gas with high content of C2+higher fractions fed from the well mouth through borehole-drill string annulus of the gas well is sent to low-pressure chamber of this ejector. |
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Development method of oil deposit at late stage Method involves drilling of production and injection wells, pumping of displacement agent through injection wells and extraction of the product through production wells, drilling of additional wells, and development of residual oil-saturated intervals. According to the invention, in all newly drilled additional wells there determined are residual oil-saturated and flooded intervals prior to the well casing. For that purpose, one-stage determination of temperature field is performed throughout the length of the well in real time both at filling of the shaft with heated washing liquid or water and after it is filled using an optic-fibre system. In case of absorption of washing liquid or water, volume of their supply, which provides full filling of the well, is increased. After the well casing residual oil-saturated and/or water-saturated intervals are developed, and displacement agent is extracted and/or pumped. |
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Development method of oil deposits with horizontal wells Method involves drilling of a horizontal well with a descending working face to the formation bottom, injection of displacement agent and extraction of the product. According to the invention, investigation of the well is performed, level of oil-water contact (OWC) is determined; after that, an ascending shaft to the formation roof is drilled out of the horizontal well at the distance of 150-500 m from the descending section. Secondary drilling of the formation is performed below OWC level in the descending section and above OWC level in the ascending shaft. The ascending shaft between the horizontal wall and the opening is equipped with a packer with a valve passing the product of the formation to the horizontal well, and the horizontal well between the descending section and the ascending shaft is equipped with an additional packer with a spring-loaded valve passing the liquid from the horizontal shaft to the opening of the descending section at the pressure exceeding hydrostatic pressure in the well. After that, a pump is lowered on tubing to the well, by means of which the product of the formation is extracted from the ascending shaft above OWC level. At reduction of formation pressure the pump recovery of the formation product is stopped, and displacement agent is pumped via inter-tube space through the descending section and the spring-loaded valve of the additional packer to the formation below OWC level to maintain formation pressure. Then pumping is stopped, and the pump recovery of the product is continued. When necessary, pumping cycles of displacement agent are repeated. |
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Method of simultaneous and separate operation of injection well Method involves separation of formations in a well with a packer, pumping of liquid to each formation via its pipe string, interruption of pumping to both formations, continuation of pumping to the formation with high permeability and continuation of pumping to both formations. Strings at the well head are connected with a disengaged connection strap. First, maximum allowable requirements for pressure and intake capacity for low-permeability formation are determined. Interruption of pumping is performed after reduction of intake capacity and rise of pressure at the head of the pipe string interconnected with the formation with low intake capacity to maximum allowable requirements. Pumping to the formation with high intake capacity is performed owing to liquid flowing from the formation with low intake capacity via pipe strings through the connection strap till the wellhead pressure is equalised; after that, liquid residues are removed from the formation with low intake capacity to a movable tank in the near-wellhead zone. |
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Development method of oil deposit in fractured reservoirs Method involves arrangement of production and injection wells, pumping of displacement liquid through injection wells and extraction of the product through production wells. According to the invention, the first injection well is developed for pumping of displacement liquid with development of interval of oil-water contact (OWC) of the formation. Extraction of the product is performed from production wells with developed oil-saturated intervals of the formation, which envelop it. To the first injection well there performed is cyclic pumping of displacement liquid with 400-500% of compensation of product extraction from production wells enveloping it. After flooding in fractures of one of production wells enveloping the first injection well, isolation of the developed oil-saturated interval of the formation in the same well is performed with development in it of interval of OWC of the formation and with its being changed over to the second injection well for pumping of displacement liquid with 400-500% compensation of the product extraction from production wells enveloping it after flooding in fractures of one of the production wells enveloping the second injection well. Isolation of oil-saturated interval of the formation is performed in the same well with development in it of OWC interval and with its change-over to the third injection well. Gradually, as fractures are being developed, a row of injection wells is created on the oil deposit, to which displacement liquid is pumped. After flooding for 70-80% of production wells enveloping each of the injection wells, that injection well is changed over to extraction of the product after the development interval is changed from OWC to oil-saturated interval of the formation. |
Another patent 2528807.