Development method for high-viscosity oil or bitumen field

FIELD: oil and gas industry.

SUBSTANCE: method of high-viscosity oil or bitumen field development involves construction of two horizontal wells, one above the other, steam injection to the reservoir, reservoir heating by steam pocket formation, steam and hydrocarbon solvent injection to horizontal injector, and product sweeping from horizontal producer. Associated gas is used as hydrocarbon solvent. Steam and associated gas are injected in sequence in cycles. Steam is injected to the reservoir until extracted product viscosity is 3-5 times higher than initial viscosity at the cycle start, associated gas injection is started along with product extraction until extracted product temperature is reduced by 10-25%, then steam and associated gas injection cycles are repeated.

EFFECT: expanded reservoir coverage, higher level of high-viscosity oil and bitumen production along with material and power cost reduction.

1 ex, 1 dwg

 

The proposed method relates to the oil industry, in particular to the field of development of deposits of heavy oil under the cyclic influence of steam and hydrocarbon solvent to the reservoir through the horizontal injection wells.

The known method of development of deposits of heavy oil (patent RU №2379494, IPC EV 43/24, publ. 20.01.2010, bull. 2), which uses pairs of horizontal injection and mining wells. Horizontal sections of these wells are placed in parallel one above the other in the vertical plane of the productive formation. Well equipped with a column tubing that simultaneously allows the injection of the coolant and the selection of products, the pumping of the coolant, the heating of the productive formation with the creation of the steam chamber, selection of products through the producing well and control of technological parameters of the reservoir and wells. The end columns of tubing fitted at opposite ends of the conventionally horizontal section of the wells. The heating of the productive formation starts with the injection of steam in both wells, warm up the interwell area of the reservoir, reduce the viscosity of heavy oil. Injection of coolant, extending to the upper part of the reservoir, creating a steam chamber. Increase the size of the steam chamber, in the process�e selection of products periodically, 2-3 times a week, determine the salinity of withdrawals along the way. Analyze the impact of changes in salinity along the way withdrawals on the uniformity of heating of the steam chamber. Taking into account the changes of mineralization along the way withdrawals carry out uniform heating of the steam chamber by regulating the mode of injection of the coolant or the selection of production wells to achieve stable salinity withdrawals along the way.

The method is not sufficiently effective in the development of deposits of heavy oil, because in the process of steam injection into the formation is not carried out monitoring of changes in the viscosity of the product in the reservoir, so there are no data on the amount deposited in the reservoir of oil fractions with high boiling point and high viscosity. The result is a poor coolant flow and are not reached planned levels of selection of high-viscosity oil.

The closest in technical essence is a method of development of deposits of heavy and servicebasic oil (patent RU №2387818, IPC EV 43/24, publ. 27.04.2010, bull. No. 12), including the injection of steam into the reservoir, heating the reservoir to create steam chamber, co-injection of steam and hydrocarbon solvent and the selection of products. According to the invention as a hydrocarbon solvent, a mixture of hydrocarbon charge�wow aliphatic and aromatic series, the main component of which is benzene. Joint injection of steam and hydrocarbon solvent is carried out after reaching the temperature in the steam chamber is not less than the phase transition temperature of the mixture of steam and hydrocarbon solvent with the support temperature in the steam chamber is not lower than the phase transition temperature of the mixture steam - hydrocarbon solvent.

The disadvantage of this method is that the injected volumes of steam and a hydrocarbon solvent into the reservoir are carried out without regard to their influence on the change in the viscosity of the product in the reservoir. Not carried out the monitoring of the evolution of the fractional composition of oil in the process of steam injection and hydrocarbon solvent, there are no data on the amount deposited in the reservoir of oil fractions with high boiling points and high viscosity. The result is wasted steam and costly hydrocarbon solvent, are not reached planned levels of selection of high-viscosity oil.

Technical tasks of the proposed method are the increased level of extraction of heavy oil or bitumen and the reduction of material costs and energy savings resulting from continuously monitoring the viscosity change of the output, allowing you to adjust the volume of injection of steam and associated gas, which�s increase the coverage of reserve recovery of heavy oil or bitumen.

The technical problem solved by the method of development of heavy oil or bitumen, comprising the construction of two horizontal wells, one above the other, pumping steam into the reservoir, heating the reservoir to create steam chamber, steam injection and hydrocarbon solvent in horizontal injection wells and selection of products from extractive horizontal wells.

What is new is that as the hydrocarbon solvent used associated gas, and injection of steam and associated gas are cyclically and sequentially, steam is injected into the reservoir to increase the viscosity of the selected products in 3-5 times in comparison with the initial viscosity at the beginning of the cycle, start to inject the associated gas with the selection of a product to reduce the temperature of selected products by 10-25%, after which the cycles of steam injection and associated gas from the product selection is repeated.

The drawing shows a diagram of the proposed method of development of deposits of heavy oil or bitumen.

The inventive method is carried out in the following sequence.

Deposit 1, comprising one or more layers, razvarivat wells on a sparse grid. Clarify the geological structure of the deposits 1. Determine the permeability, the porosity of the reservoir, the viscosity of the heavy oil or bitumen.

Conduct hydrodynamic research about�the definition of reservoir pressure, temperature. Selecting the area with the net pay thickness h of more than 15 meters Drilled horizontal injection well 2. Below the mining seam is drilled horizontal well 3.

Horizontal wells 2, 3 are placed one above the other in the same vertical plane at a distance l=5-7 m, which prevents premature breakthrough of the condensate to extractive horizontal well 3. Flush tubing with centralizers, with filter (not shown) in the interval of the productive formation.

Extractive horizontal well 3 is carried out in the most permeable bed, and it is located above the base layer 4 of high-viscosity oil or bitumen at a distance of 3-4 m, and oil-water contact (OWC) is at a distance of a≥6-7 m, anhydrous increasing the period of operation of the well.

A shorter distance to OWC will lead to a breakthrough of bottom water to the horizontal well bore 3 as a result of sharp differences in the viscosities of heavy oil or bitumen and produced water.

According to the tax code of the Russian Federation, with the introduction of a differentiated tax on mineral extraction (met), adopted the following classification of oil to viscous (heavy) oil is oil, whose viscosity at reservoir conditions is 200-10000 MPa·s, to sverkhvysokogo (bitumen) - oil � viscosity at reservoir conditions of over 10,000 MPa·s.

High viscosity oil or bitumen causes the application of borehole thermal methods of mining with an additional injection of solvents, which are the individual chemical compounds or mixtures capable of dissolving a variety of substances, i.e., to form with them a homogeneous system of variable composition, consisting of two or more components. When exposed to heavy oil or bitumen with solvent in the form of associated gas there is a complete mixing them with a solvent, whereby the viscosity is reduced.

The mechanism of displacement of heavy oil or bitumen with steam is to spread the zone of influence of steam on stratum with increasing reservoir pressure. The injected steam tends to the upper part of the formation. On the boundary of the steam chamber when the transfer of the condensation heat, and the heated heavy oil or bitumen are displaced under the action of gravity to the bottom of the extractive horizontal well 3.

The fix vapor produced in injection horizontal well 2 cycles with simultaneous selection of products from extractive horizontal wells 3 and speed control of heating of the formation. As in the warming-up process and the operation process is carried out monitor the temperature in the bottom-hole zone wells with special d�of tchekov (thermocouples), omitted inside paramagnetically pipes. Comparison of temperature observations, measurements of flow rate, oil-water relationship in time, the viscosity of heavy oil or bitumen, as well as the dependence of these parameters on changes in the rate of steam injection will allow you to pick the optimum pressure mode. The steam injection mode may be different, however, the bottomhole pressure must not exceed the overburden pressure, i.e. the pressure under which the rock in the reservoir. It must be borne in mind that the higher the steam flow, the more is taken of condensate from horizontal producing well 3.

Obligatory condition of steam injection is the gradual warming up of horizontal injection wells 2 and uniform heating of the casing and cement to prevent them from cracking.

After steam injection in the upper horizontal injection well 2, exposure to thermocapillary impregnation, extractive horizontal well 3 starts to work. When the temperature of the reservoir to plus 100°C and higher the viscosity of heavy oil or bitumen is sharply reduced, increased permeability of the rocks composing the aquifer. Selection of product from the reservoir increases. The higher the heterogeneity of the heavy oil or bitumen, the slower the decrease of the viscosity. Fractional composition of oil showing�for the content of the various components, having different boiling points. In the reservoir in the first place there is a decrease in the viscosity of a light fraction with a relatively low boiling point (100°C and above) and their selection. In the process of further steam injection increases the coverage area of reserve recovery of heavy oil or bitumen, which leads to the loss of heat in the reservoir and increase the viscosity of products. The proportion of light fractions is reduced, increasing the share of fractions with a high viscosity and boiling point. Heavy oil is deposited in the reservoir, resulting in reduced permeability and, as a result, the oil production rates.

By increasing the viscosity of the selected products in 3-5 times in comparison with the initial viscosity at the beginning of the cycle of the injected vapor replace the associated gas.

Associated gas is pumped in annulus horizontal injection wells 2, to heat up the casing string (not shown), but it increases the temperature of the injected gas into the reservoir and increases the reserve of elastic energy in the reservoir, providing further flow of product from the reservoir in extractive horizontal well 3. Increasing the pressure leads to the increase in displacement due to the additional areas of the reservoir. In order to avoid uneven distribution of the displacement front high viscosity �of eti or bitumen, bottom-hole pressure in the injection wells 2 does not exceed the pressure of hydraulic fracturing.

Under these conditions the lowest steam consumption for production of one tonne of heavy oil or bitumen.

When the temperature of selected products by 10-25% compared with the temperature at the beginning of the cycle, the injection of associated gas is replaced by the injection of steam. The consecutive cycles with steam injection and associated gas into the reservoir again.

An example of a specific implementation.

Deposit 1 heavy oil, presented in a single layer, razvarivat wells on a sparse grid. Choose a site with effective net pay thickness h=20-25 m. the Lower boundary for the reservoir is oil-water contact (OWC). Determine the permeability, which is equal 0,114 μm2. The porosity varies in the range from about 16.2 to 19.4%. Oil viscosity is an average of 720 MPa·s.

Drilled one horizontal injection well 2. Below the horizontal seam is drilled production well 3. Horizontal boreholes 2, 3 are placed in the same vertical plane. The casing is installed in the reservoir cemented the annulus of casing (not shown) to the top of formation. Flush tubing with centralizers, with filter (not shown) in INTA�Vale formation. The distance l between the horizontal injection well 2 and primary 3 wells is 5-7 m. the trajectory of the horizontal producing well 3 have the above oil-water contact 4 to 8 m - minimum distance h, anhydrous increasing the period of operation of wells. A shorter distance to oil-water contact 4 will lead to a breakthrough of bottom water to the trunk of the extractive horizontal wells 3 as a result of sharp differences in the viscosities of heavy oil and produced water. Install tubing with a filter in the reservoir interval, equipped with centralizers. Injection of steam is carried out through the upper horizontal injection well 2 with the wellhead. Periodically determine the volumes of injected steam and produced fluids, water cut, pressure at the mouth and the bottom of the wells 2, 3.

In injection horizontal well 2 was pumped 1.7 tons of steam and 135 thousand m3associated gas. Injection of steam temperature 180-200°C was carried out at a pressure at the mouth of 1.2-1.5 MPa cycles, not exceeding 2 days. The average rate of discharge was 2.6 t/h or 63 tonnes. The maximum amount of steam produced per cycle was 94 tons, with an average of 31.0 T. water Cut reached 70,0%. To relieve thermal stresses with the production casing horizontal injection wells 2 � increasing selection of products from extractive horizontal wells 3 when the viscosity increase of 3.2 times until 108,8 MPa·s compared with the initial viscosity (34,0 MPa·s) at the beginning of the cycle of steam injection into the reservoir, injection of steam was replaced by injection of associated gas in the annulus horizontal injection wells 2. After two days when the temperature drops in the reservoir by 16% to 128°C resumed pumping steam into the reservoir. Further cycles are repeated.

As a result of cyclic steam injection and associated gas into the reservoir production rates for heavy oil increased from 0.3 to 0.5 t/d to 3.1 and 6.4 t/day.

When cyclic injection of steam and associated gas into the reservoir, the steam consumption for heating is reduced in proportion to the length of the cycle. The cost of a hydrocarbon solvent (benzene) is high, comparable to the cost of gasoline, so the cyclic injection of associated gas produced along with crude oil, a hydrocarbon solvent multiples will reduce material costs.

The proposed method allows to increase the coverage of the formation impact and production of heavy oil or bitumen as a result of constant monitoring of changes in the viscosity of the produced output, providing the ability to control the steam injection process and associated gas, but also reduce energy consumption for heating steam at its cyclical usage.

Method of development of deposits of heavy oil or bitumen, comprising the construction of two horizontal wells, one above the other, fix a couple � layer, the heating of the reservoir to create steam chamber, steam injection and hydrocarbon solvent in horizontal injection wells and selection of products from extractive horizontal wells, characterized in that the hydrocarbon solvent used associated gas, and injection of steam and associated gas are cyclically and sequentially, steam is injected into the reservoir to increase the viscosity of the selected products in 3-5 times in comparison with the initial viscosity at the beginning of the cycle, start to inject the associated gas with the selection of a product to reduce the temperature of selected products by 10-25%, after which the cycles of steam injection and associated gas from the product selection is repeated.



 

Same patents:

FIELD: oil and gas industry.

SUBSTANCE: method of oil field development by a horizontal and vertical well system using thermal impact involves horizontal and vertical well drilling and equipment, so that vertical well bottom is located below horizontal well bottom at a design vertical distance of 3 to 7 m, formation of heating area by injection of combustible oxidising mixture (COM) and combustion initiator (CI) to ignite and warm-up the inter-well zone up to 100-200°C, depending on COM and CI type, and to establish hydrodynamic connection between wells; horizontal well is switched to liquid production by a pump, with continued supply of COM and CI to the vertical well to maintain burning and warming-up of the field to 250-350°C which is the temperature of independent burning of COM; afterwards, CI supply is stopped, and COM injection continues to maintain and promote burning along the horizontal wellbore. During construction, horizontal well is equipped with a filter with several zones along the horizontal section length. Before pump landing in the horizontal well, a liner with thermocouples installed inside it for temperature monitoring inside the well opposite to filter zones, that allows for serial opening of only one zone during turning and for shutting filter zones from bottomhole to wellhead. Zone adjoining the bottomhole is opened initially. After combustion initiation, if temperature in this zone falls down from the maximum achievable by combustion in the field conditions to 85-95°C, product pumping is stopped, the liner is turned from wellhead to a definite angle ensuring bottomhole zone shutoff and opening of the next zone used for further product extraction by pumping. After temperature in this zone changes from the maximum achievable by combustion in the field conditions to 85-95°C, this zone is closed by a turn of the liner opening the next zone from the bottomhole, and similarly zones are opened and shut in sequence till the last filter zone from the bottomhole.

EFFECT: optimised operation of horizontal well, reduced power cost of its operation, expanded effective coverage of horizontal producer effect, reduced content of gas in the product extracted, enhanced depletion of oil field stock.

1 ex, 3 tbl, 8 dwg

FIELD: oil and gas industry.

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21 cl, 5 dwg, 2 tbl

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FIELD: oil and gas industry.

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EFFECT: increased extraction efficiency.

34 cl, 1 dwg, 2 ex

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EFFECT: maximising liquefaction of heavy oil and maximising its extraction as a result.

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FIELD: oil and gas industry.

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EFFECT: improving destruction efficiency of a filter cake.

20 cl, 6 dwg, 3 tbl, 2 ex

FIELD: oil and gas industry.

SUBSTANCE: under the method of development of oil deposits with nonuniform permeability comprising successive injection via the injection well of the water suspension containing polymer, mud powder and SAS solution, prior to the suspension injection in the deposit the initial intake of the injection well is determined under pressure in water line ands water mineralisation; in water with salinity level 0.15-40 g/l complex action SASs with pour point not exceeding minus 30°C and kinematical viscosity 35-50 sSt are used, i.e. water-alcohol solution of non-ionic SAS-monoalkyl esters of PEG at the following ratio wt %: specified SAS 0.001-1.0, specified water rest, suspension and SAS solution are injected in volume ratio (1-3):1 depending on initial intake of the injection well - at intake 200-400 m3/day - 1-2:1, 400-500 m3/day - 2-3:1, over 500 m3/d - 3:1, between suspension and SAS solution water with salinity level 0.15-40 g/l or water suspension of polyacrylimide with concentration 0.0001-0.1 wt % is injected. Under another option during this method in water with salinity level 40-300 g/l the complex SAS with pour point minus 40°C max is used, containing complex action SAS with pour point minus 30°C max. and kinematical viscosity 35-50 sSt - water-alcohol solution of non-ionic SAS - monoalkyl esters polyoxyethylene glycol 90 wt % and alkyldimethylbenzylammonium chloride 10 % at following ratio of components in wt %: specified SAS 0.001-1.0, specified water - rest, suspension and SA solution are injected to the deposit in volume ratio (1-3): 1 depending on initial intake of the injection well at water line pressure - at intake 200-400 m3/day - 1-2:1, 400-500 m3/day - 2-3:1, over 500 m3/day - 3:1, and between suspension and solution the water with salinity level 40-300 g/l or water suspension of polyacrylimide with concentration 0.0001 0.1 wt % are injected.

EFFECT: increased oil recovery of the deposit.

2 cl, 4 ex, 4 tbl

FIELD: oil and gas industry.

SUBSTANCE: under method of oil deposit development comprising determination of the injection well intake, oil recovery via the production wells, and injection via at least one injection well of the water dispersion of the water-soluble polymer and alkali metal hydroxide, this dispersion contains in wt %: water-soluble polymer 0.01-0.05, alkali 0.5-1.0, at definite intake values of the injection well the specified dispersion is injected until injection pressure increasing by 20-30%, its flushing in the deposit by the injected water in volume of tubing plus 1.0 m3, alkali composition in volume 10-30% of volume of injection of the specified dispersion is injected until specific intake decreasing by 10-20% and achievement of the injection pressure not exceeding the maximum permitted pressure on production string and production deposits, the specified compositions at specified water salinity under each of three options, and flush by water in volume 10-15 m3.

EFFECT: increased oil recovery of deposits and watercut reduction of production wells, spreading of process abilities.

3 cl, 1 ex, 2 tbl

FIELD: oil and gas industry.

SUBSTANCE: method envisages the usage of aqueous solutions of binary mixtures - inorganic or organic nitrate or hydrate of alkali metals, which are injected through individual channels. The method includes the mounting of equipment in wells at the selected area of a deposit. Each well is equipped with devices to control the temperature, pressure and composition of reaction products in a real time mode. Formation areas in vicinity to the well with a volume of at least 20 m3 are heated preliminarily up to a temperature of at least 100°C by injection of at least 2 t of binary mixture reagents. Cyclic heating of the formation area in vicinity to the well with a volume of at least 100 m3 and weight of 250 t is made up to a temperature of at least 140°C due to a reaction of at least 12 t of the binary mixture reagents. At that the first level of explosion safety is ensured by the alternation of injection of saltpetre solution portions, 1 t each, with portions of industrial water of at least 0.05 t each. The second level of explosive safety in the borehole is ensured by the continuous control and monitoring of the reaction process with the temperature limitation in the well bore below the pre-blasting temperature. This temperature is determined against signs of the reaction self-acceleration at recorded charts of time-temperature and time-pressure curves. In case of these signs the injection of a saltpetre decomposition initiator is stopped to the well. Further injection of the saltpetre solution with the weight of at least 10 t is made to the preheated formation. At that the third level of explosive safety is implemented in the reaction process in the formation, which is catalysed by the heat accumulated during the previous cycles. The third level of explosive safety is ensured by a ratio of the weight of the saltpetre injected to the pores and fractures of the formation to the weight of the rock. The ratio is equal mainly to 1 to 20. Low explosive probability, close to zero, is ensured by a mixture of 95 wt % of rock and 5 wt % of saltpetre. The injection of reagents at all cycles is made at continuous temperature control in the reaction zone and pressure and temperature control in the zone near the packer and in the process of the reagents injection for the purpose of timely cessation of the reaction when the parameters of the reaction exceed limits of permitted modes.

EFFECT: improved efficiency of oil production at worked-out deposits with an increased production safety.

4 cl

FIELD: oil and gas industry.

SUBSTANCE: this invention is related to production of oil-in-water emulsions with low viscosity during operations with oil. The method for reduction of apparent viscosity for hydrocarbon fluids occurring at oil extraction and transportation includes contact of the above hydrocarbon medium with effective quantity of composite containing at least one polymer with at least 25 mole percent of cationic monomers. The invention has been developed in dependent claims.

EFFECT: increase in oil production.

15 cl, 9 ex, 4 tbl, 4 dwg

FIELD: oil and gas industry.

SUBSTANCE: treatment method of underground hydrocarbon-containing formations involves the following: a) provision of a composition including a thickening initiator measuring pH, and a polymer capable of hydration in a certain pH range; b) pumping of a composition with pH value beyond the limits of the above pH range; c) activation of an action of pH thickening initiator for displacement of pH composition to the above range of its values, and d) provision of a possibility of increasing viscosity of the composition and shaping of a plug. According to another version, a processing method of underground hydrocarbon-containing formations involves the following: a) provision of a composition containing a polymer capable of hydration in a certain pH range; b) pumping of the composition with pH value beyond the limits of the above pH range; c) provision of a pH changing thickening initiator; d) activation of the action of the thickening initiator for displacement of pH composition to the above range of its values, and e) provision of a possibility of increasing viscosity of a composition and shaping of a plug. The invention has been developed in dependent claims.

EFFECT: improving efficiency of initiation and control of plug formation.

15 cl, 5 ex, 3 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: invention relates to oil production, particularly, to from underground oil deposits. In compliance with this invention, at least one production well and one injection well can be used. Temperature distribution in the zone between said wells is analysed. In case temperature is distributed between said zones so that minimum temperature makes at least 20°C, maximum temperature does not exceed 320°C, while their difference makes at least 20°C, aqueous gel-forming preparations are injected via injection well that contain one or several chemical components. These preparations after injection in the deposit form gels under the effects of deposit temperature. Said preparations differ in type and/or concentration of chemical components. Chemical components and/or their concentration are selected to make gel-forming temperature and/or geol-forming time of the second and, if required, any other injected portion, differ from portions injected there before.

EFFECT: higher efficiency of oil extraction due to levelling of injectivity.

19 cl, 4 tbl, 7 dwg

FIELD: oil and gas industry.

SUBSTANCE: according to the method the first and second banks are injected through a hydrocarbon- or water-based displacement fluid to the designed area of the well. At that the availability of a residual saturation area is determined in productive formations with loose - loosely cemented porous and/or fractured reservoirs. The availability of an ultimate water saturation area, an undersaturated transition interval with a film water area and an intensive flow of water diffuse layers and a subarea of high oil content is determined. The availability of ultimate oil saturation is determined. The availability or unavailability of shale barriers at boundaries of the ultimate water saturation area and the transition interval is considered. The water saturated area is cut from the ultimate oil saturation area and an oil inflow is ensured to the productive formation from the subarea of high oil content. Injection is made to the design area of a producer and/or injector. At that the displacement fluid in injected in a quantity of 0.1 up to 500% of the first bank volume. The second bank is injected in a quantity of 0.1-250% of the first bank volume. Polymer resin is used as the first bank. Polymer hardener is used as the second bank. Upon injection the well is transferred to the hydrocarbon inflow mode.

EFFECT: increased efficiency of the method.

24 cl, 47 ex, 1 dwg

FIELD: oil and gas production.

SUBSTANCE: invention provides a method of developing oil pool allowing production of oil from water-rich oil reservoir under difficult geological-tectonic conditions in the last development stage. In the method, neutral salt of carbonic acid and acid solution are forced into formation through injecting well with water generated in gas-liquid fringe created in formation. After pumping of neutral salt of carbonic acid, acid solution is pumped by portions alternating with water pumping. Before pumping of acid solution portions beginning by at least second portion, selective insulation of high-permeable formation intervals is performed. Aforesaid neutral salt of carbonic acid utilized is sodium carbonate aqueous solution or aqueous suspension of calcium carbonate and aforesaid acid solution is aqueous hydrochloric acid solution. Selective insulation of high-permeable formation intervals involves use of freshly prepared controllable viscoelastic composition containing water-soluble acrylic polymer, cross-linking agent, thermal stabilizer, surfactant, and water. Summary concentration of acid solution is determined from concentration of neutral salt of carbonic acid on the base of stoichiometric proportions.

EFFECT: increased efficiency of maintaining formation pressure and thereby oil recovery of formation due to leveled displacement front and reduced probability of the rupture of formation rock backbone, and simplified control of phase state of gas-liquid fringe by changing pressure of pumped acid solution portions.

8 cl

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