RU2562634C2 - Reservoir recovery improvement method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is referred to oil industry, in particular, to treatment of producers and injectors with hard to recover reserves. In reservoir recovery improvement method that includes subsequent injection to the reservoir of at least two equal portions of polymer fringe in water and salt cross-linking agent in water with water buffer between them AMG reagent is used as cross-linking agent and fringes of argillic agent in water and fringes of multifunctional agent and aliphatic and/or aromatic alcohol or bypass products containing them are injected additionally with provided reduced interfacial tension in oil-water system up to 0.005 mN/m, with the following sequence of fringes with the following composition, wt %: 1) 0.001-3 polymer in water, 2) 0.0001-0.5 AMG in water, 3) 0.0001-20 argillic agent in water, 4) multifunctional agent 0.1-99.9 and the above alcohol and bypass products in the remaining volume with ratio of the composition 1) and multifunctional agent equal to 1: (0.06-0.25) or 1) 0.001-3 polymer in water, 2) 0.0001-0.5 AMG in water and 3) 0.0001-20 argillic agent in water, 3) multifunctional agent 0.1-99.9 and the above alcohol and bypass products in the remaining volume with ratio of the composition 1) and multifunctional agent equal to 1:0.06-0.25.

EFFECT: improving efficiency.

3 ex, 1 tbl

Description

The invention relates to the oil industry, namely, to increase oil recovery of terrigenous and carbonate formations of oil fields with heterogeneous reservoirs and hard-to-recover oil reserves at any stage of flooding, by applying the claimed sequence of operations and chemicals, and the claimed technical solution can be used for processing production and injection wells when working on oil fields.

A known method for processing injection wells is RF patent No. 2138626, which consists in extracting residual oil from an irrigated heterogeneous formation and including oil displacement using a micellar solution containing a water-soluble surfactant, an oil-soluble surfactant, a hydrocarbon liquid, and water, in which it is additionally injected into the formation or directly into In the process of pumping a micellar solution, isolation of highly permeable zones of the formation is carried out by injection of finely dispersed solid particles. The main disadvantage of this method is the presence of a micellar solution having low resistance to water of low and high salinity, as a result, the lack of efficiency of oil recovery from low permeable oil-saturated zones. A known method of processing the bottom-hole zone of wells that produce heavy oils and bitumen, RF patent No. 2144982, which consists in injecting into the reservoirs an aqueous alkaline emulsion of light pyrolysis resin with the addition of ferromagnetic components and the bottom residue of the production of synthetic fatty acids, exposure to ultrasound with a frequency of 100-1000 Hz at the temperature of the initial liquids 70-80 ° C. Before the formation of emulsions, aqueous solutions can be saturated with air in an amount of 1-550 dm ³ per 1 m ^{3 of} solution.

The main disadvantage of this method is the significant energy costs, because it requires ultrasound, with a frequency of 100-1000 Hz, with turbulent mixing with the temperature of the initial components of the emulsion 70-80 ° C, and the technological complexity of processing, because gas saturation of aqueous alkaline solutions, for example, air, is used in an amount of 1-50 dm ³ per 1 m ^{3 of the} solution before exposure to ultrasound, which significantly increases not only energy costs, but also significantly increases the complexity of the process and, as a result, increases the time interval well treatment.

A known method of increasing oil recovery, RF patent No. 2425967, by regulating the permeability of oil deposits, including the injection into the reservoir of a composition containing clay and a solution of a metal salt, as the specified composition, a clay solution with the addition of magnesium sulfate is used. The disadvantage of this method is the narrow selective focus of the technology and the technological complexity of the preliminary calculations, due to the individual characteristics (properties) of the composition used, due to the fact that the following necessary conditions limiting the application of the technology are required:

- Establishment of carbonate potential horizons;

- determination of the composition of carbonate material and produced water at each well;

- determination of the isotopic composition of carbon CO2 and carbonates.

The known method is also implemented through the features of the composition used, and the composition only works if the percentage of rock carbonate is high enough (d13C values of carbonate rocks, which in one zone are 0.5-0.8%, and in the other 1.3-3 , 7%, the dolomitization coefficient is higher than 15.0%), otherwise, the method of implementing the technology for injecting magnesium-containing fluid into the formation becomes unprofitable or is not possible.

Closest to the claimed method, in terms of the set of matching features and the technical result achieved, chosen by the applicant as a prototype, is a method for increasing oil recovery of a heterogeneous oil reservoir according to RF patent No. 2436941, comprising sequential injection of a polymer in water and an aluminum salt solution with a water buffer between them, where the volume of the injected polymer in water, used in the form of a suspension, and the aluminum salt solution are divided into equal portions of at least two and a volume of 3-50 m ³ , which are pumped by therefore, cycles with the injection of a water buffer between them, amounting to 10-100% of the portion size of each, to exclude their mixing during injection through pipes and to control the distance of their mixing from the well in the reservoir.

The disadvantage of this method of simultaneous (joint) injection of the composition of the injected polymer in water and a solution of aluminum salt into a group of injection wells from the comb unit (BG) of a cluster pump station (SPS) is:

- the absence of the directed action of the polymer system on a water-saturated formation, i.e. it is impossible to guarantee when the known composition is pumped into the group of injection wells and when it is further advanced naturally, it is distributed in the formation coverage area by water flooding, while advancing in the indicated way, the gel formed during the reaction can colmate the oil-bearing layer and the effect on the formation as a whole will not be effective;

- when pumping through long pipes of SPS, there is the possibility of an emergency due to adsorption (deposition) of adhesive polymer solution on the pipe walls and their overgrowing;

- the use of the used composition of a solution of polyacrylamide (PAA) in water and a solution of aluminum salt, namely aluminum sulfate (SKA), when exposed to the formation is not very effective due to the insufficient strength of the crosslinking of PAA with SKA, which leads to low viscoelastic properties of the gel obtained by the reaction;

- the lack of phobizing ability of a known composition leads to insufficient efficiency of the method as a whole;

- the lack of complex effects of the applied technological solutions, because the application of the known technical solution is intended "for effective isolation" of waterlogged zones of wells.

This problem is solved by the fact that in the method of increasing oil recovery, including sequential injection into the reservoir by cycles of at least two polymer rims in water and a salt cross-linking agent in water with a water buffer between them divided into equal portions, AMG reagent is used as the salt cross-linking agent and additionally carry out the rims of the clay agent in water and the rims of the multifunctional reagent and aliphatic and / or aromatic alcohol, or a waste product containing them, with reducing interfacial tension in the system of the "oil-water" to 0.005 mN / m, in the following sequence rims and following their compositions, wt.%:

1) 0.001-3 polymer in water

2) 0.0001-0.5 AMG in water

3) 0.0001-20 clay agent in water

4) a multifunctional reagent 0.1-99.9 and the indicated alcohol or the rest, with a ratio of the composition 1) and a multifunctional reagent equal to 1: (0.06-0.25)

or

1) 0.001-3 polymer in water

2) 0.0001-0.5 AMG and 0.0001-20 clay agent in water

3) a multifunctional reagent 0.1-99.9 and the indicated alcohol or the rest, with a ratio of the composition 1) and a multifunctional reagent equal to 1: 0.06-0.25.

This effect is ensured by reducing the permeability of high-flooded interlayers, leading to an increase in water coverage during flooding both in thickness and in strike, which contributes to the involvement of low-permeability oil-bearing formations in the reservoir by reducing interfacial tension between oil and water, increasing the rate of phase interactions, which leads to a deeper penetration of reagents into the oil reservoir and an increase in oil recovery in general, while at the same time providing lower reduction of water consumption for oil recovery.

Due to the improved thermal stability and chemical resistance of the used reagents and their compositions in comparison with the known compositions, especially under conditions of high salinity of the formation water, there is an improvement in the phase permeability for oil due to the improvement of the rheological, wetting and demulsifying properties of the injected compositions at a lower cost of time, materials for processing formation, in addition, it is possible to prepare compositions, including in the winter season at minus temperatures D to minus 45 ° C. A decrease in the permeability of the washed zones of the oil-bearing formation and an increase in the oil-displacing properties of water are provided due to the combination of the properties of the compositions and the indicated sequence of their injection. Moreover, the claimed method provides the implementation of additional tasks, namely due to the selective exposure of the used reagents to the rock surface, the molecular surface properties of the rock, produced water and oil are changed. The self-organization of phase transitions in the reservoir conditions is also provided, namely, a change in the phase permeability for oil and water, i.e. the possibility of a reversible change in the wettability of the rocks from “philic” to “phobic” contributes to an increase in the rate of capillary absorption, which is accompanied by the release of energy from a highly developed (solid, gas, liquid) interfacial interface of oil reservoirs.

Thus, the resulting excess energy that occurs each time a new phase is formed, for example:

- with a constant change in the molecular-surface properties of the rock of the oil reservoir,

- with a decrease in interfacial tension in the oil-water system to 0.005 mN / m,

- when overlapping layers of the liquid and gas phase at the molecular level, it provides acceleration of the processes of separation of oil from the surface of the rocks and the further movement of globular oil in channels with a variable section of the reservoir.

The above explanations for the claimed technical solution in the aggregate can significantly increase the oil recovery of the reservoir.

The features of the invention are:

1) oil extraction through a producing well;

2) cyclic injection into the formation of flocculant fringes in the form of polymers in water, a natural crosslinking agent and a solution of alkali metal salts in water with a water buffer between them;

3) the volume of injected reagents is divided into equal portions of at least two, pumped sequentially in cycles with the injection of a water buffer between them, amounting to 1-100% of each portion;

4) the volume of injected reagents varies between 10-10000 m3 depending on the well conditions;

5) in addition, a rim of multi-functional reagents and aliphatic and (or) aromatic alcohols and (or) production wastes containing them are used;

6) multifunctional reagents can be pressed into the formation without a buffer rim of water and (or) oil;

7) physico-chemical resistance when interacting with mineralized water up to 271 g / l and high formation temperature up to 90 ° C of the used multifunctional reagents allows you to use them in terrigenous and carbonate reservoirs;

8) the manufacturability of the claimed technical solution, because the possibility of processing both vertical and horizontal wells is provided.

A new set of claimed essential features allows to obtain a new technical result, namely to create an effective way to comprehensively intensify oil production and increase well production by using a composition for its implementation, which has improved physicochemical properties that allow:

- increase oil recovery in productive formations with difficult to extract oil reserves from 23.2% to 37.6% through the use of the process of self-organization of phase transitions in the systems of the productive formation;

- regulate the wettability of the rocks;

- influence by improving the phase permeability of heterogeneous reservoirs containing difficult to extract oil in the microporous structure of various rocks of both carbonate and terrigenous;

- reduce the attenuation of water filtration;

- reduce unproductive costs for pumping water into injection wells and moving water through the reservoir by increasing its impact coverage;

- environmentally improve the operation of the entire oil and gas complex due to the compatibility of the used reagent composition with all types of formation fluids.

Currently, oil is produced by the method of waterflooding, since oily rocks are inherently hydrophilic in nature. When developing oil reservoirs with heterogeneous reservoirs by flooding, premature injection water breakthrough through high-permeability layers into oil producing wells results in a decrease in the efficiency of oil displacement by water and a decrease in oil recovery. In these cases, work is carried out to align the injectivity profile of injection wells. Often, the effectiveness of such work is low due to the small volumes of the resulting water-insulating composition, its insufficient strength characteristics when interacting with saline water and its low temperature resistance, as a result, phase permeability to oil often deteriorates, because partial blockage of oil reservoirs occurs. These factors impede the flow of oil in producing wells and create the prerequisites for an increase in water injection into injection wells.

The claimed technical solution solves the problem of increasing the efficiency of alignment of injectivity profiles and increasing oil recovery due to the complex effect of the chemical reagent system and the actions (operations) performed on the oil-saturated formation.

Aqueous formulations of flocculants — polymers, natural and synthetic cross-linking agents, multifunctional reagents and (or) aliphatic and (or) aromatic alcohols, and (or) industrial wastes containing them, are sequentially pumped into the reservoir, and multifunctional reagents can be pressed into the reservoir without buffer and without preliminary technological exposure. The reagents used in the claimed method is a new integrated technology PNI, the following:

- water-soluble polyacrylamides of the general formula (-CH ₂ CHCONH ₂ -) _{n of} various grades, for example FP-307, Praestol-2540, DP-9-8177 and analogs and / or water-swelling polymers of various grades, for example VNP-1, AK-639 and analogues, xanthan gums, carboxymethyl cellulose (CMC), other cellulose ethers;

- clay agent (natural crosslinking agent) - natural and / or bentonite clay powders of various grades, and / or purified montmorillonites (up to 5 nm), using and / or kaolin, and / or wood flour, and / or zeolite;

- AMG reagent according to TU 2146-003-42129794-2003 - a mixture of chromium and sulfite salts of alkali metals, depending on the ratio of a mixture of chromium and sulfite components (white and orange crystals), AMG reagent is produced in two grades: AMG-1 TU 2146 -003-42129794-2003 and AMG-2 TU 2146-003-42129794-2003; concentration of hydrogen ions, not less than pH 3.5-4.0; the density of the aqueous solution 1050-1060 kg / m ³ ;

- a multifunctional reagent - RMD according to TU 2458-011-26761699-2001 is a composite mixture with a solvent content of a wide fraction of light hydrocarbons and hydrophobizing additives, it is a light brown to black liquid with a density of 780 kg / m ³ and from 840 kg / m ³ depending on the ratio in the mixture of hydrophobizing additives 20-90 wt.% produce RMD of three grades: RMD-1 according to TU 2458-011-26761699-2001 (hydrophobizing additives not more than 20 wt.%), RMD- 2 according to TU 2458-011-26761699-2001 (hydrophobizing additives from 20 to 90 wt.%), RMD-3 according to T 2458-011-26761699-2001 (water-repellent additives are not less than 90 wt.%);

- a multifunctional reagent - RMD-5 according to TU 458-017-26761699-2007 - is a water-based composite mixture that contains alkaline electrolytes ShchSPK-M (according to TU 2432-001-42129794-2001), a water-repellent additive (TU 9197-039-00335215-2004), technical sodium polyphosphate (GOST 20219-80) and / or montmorillonite dispersed from 10 to 200 nm, surfactants may be present, it is a brown liquid with a specific odor density from 1050 to 1150 kg / m ³ , the concentration of hydrogen ions, pH 8-12.5;

VTZh-RMD-5 or ULTRAFLO high-performance process fluid; multicomponent composition is produced according to TU 2458-019-87869324-2011 of three grades: ULTRAFLO according to TU 2458-019-87869324-2011, ULTRAFLO-M according to TU 2458-019-87869324-2011, ULTRAFLO -MMP according to TU 2458-019-87869324-2011 depending on the percentage of components (RMD according to TU 2458-011-26761699-2001, RMD-5 according to TU 458-017-26761699-2007, montmorillonite dispersed from 5 to 200 nm, alkylbenzene production waste TU 2152-002-42129794-2001 and (or) inorganic salts (potassium and (or) calcium chloride, and (or) potassium bromide, and (or) calcium nitrate) and (or) co-agents (ethanol, methanol, and t .p.), a modified gelling agent TU 2146-003-42129794-2003), is a heterogeneous liquid from light to dark brown with a density of 850 kg / m ³ and up to 1650 kg / m ³ pour point not higher than minus 25 ° C , the reagent contains hydrophilic and hydrophobic ultrafine particles, their mixtures;

- alcohols: - aliphatic (methanol, ethanol, 2-propanol, 2-methyl-2-propanol, 3-methyl-1-butanol, 2-propen-1-ol (allyl alcohol), 1,2-ethanediol, 2- (2-ethoxyethoxy) ethanol); - aromatic (benzyl, 2-phenylethanol); - corresponding wastes containing alcohol from this list: desiccant - raw, produced in accordance with TU 2422-099-05766801-2000, containing at least 20.0 wt. .% ethylcarbitol, bottoms of the production of ethylcarbitol containing 15.0-22.0 wt.% basic substances, bottoms of rectification of dipropylene glycol containing wt.%, 13.0-20.0 dipropylene glycol, 34.0-40.0 tripropylene Kolya, 22.0-30.0 tetrapropylene glycol, the rest is heavy polypropylene glycols; concentrate of head impurities of ethyl alcohol (TU 9182-478-00008064-2002), an intermediate fraction of ethyl alcohol (TU 9182-479-00008064-2002); acetaldehyde-based 2-ethylhexanol by-products, wt.%: 2-ethylhexanol 45.24, 2-ethylhexanal 5.62, 2-ethylhexenal 0.83, ketones C7-C11 3.64, ethers C10-C16 8, 28, esters C10-C16 5.12, alcohols C10-C16 8.67, acids C4-C8, 2.42 hydrocarbons C11-C15 3.31, acetals C12-C24 3.35; a mixture containing, wt.%: methanol 57-58, alcohols from the group C2-C15, water 8.6-19. The complexity of the method used is to simultaneously increase the coverage coefficient by exposure and increase the coefficient of oil displacement from heterogeneous reservoirs with a change in reservoir hydrodynamics, i.e. there is an additional involvement in the development of non-drained oil reserves due to the release of energy potential during the accelerated process of phase transitions occurring in reservoir conditions, without additional injection of water into injection wells.

The novelty of the technological impact on the oil-water reservoir is as follows:

- improving the efficiency of oil recovery, ensured by a deeper penetration of the composite system into the reservoir, due to the fact that the use of ultrafine elements of the composition;

- the resistance of the water-insulating mass and the increase in its volume in the highly permeable part of the reservoir is ensured by the high strength and stability of the reagents used in the composition;

- the involvement of low-permeability layers in the work and the extraction of non-draining oil reserves occurs due to the fact that the composition used reduces the interfacial tension in the oil-water system to 0.005 mN / m, which, ultimately, leads to an increase in oil recovery.

The ability to selectively limit the movement of water in the oil-saturated zone of the reservoir occurs as a result of increased filtration resistance exclusively in flooded areas and is ensured by the following:

- the increase in the coverage coefficient by the impact and the involvement of low-permeability oil-bearing rocks in the formation occurs both due to an increase in the residual resistance factor (Roct) while increasing the apparent viscosity of the reagents used in the high-permeability rock pores, and due to the improved phase interaction of the composite system with a liquid, solid and the gaseous environment of the formation, allows you to cover the impact and engage in the work of low-permeability formations without increasing the volume of water injection into the supercharger nye wells, while simultaneously improving the filtration characteristics for oil;

- alignment of the injectivity profile as a result of the selective action of the reagents, while the effect of the selective action of the hydrophobic and hydrophilic ultrafine particles contained in the reagents is higher, the higher the ratio of the viscosity of oil and water, and the higher the heterogeneity of the formation;

- the possibility of applying the claimed technology in both horizontal and vertical wells of terrigenous and carbonate heterogeneous reservoirs of oil fields due to improved rheological properties of the composition and its increased thermal stability provide the possibility of application at reservoir temperatures of up to 90 ° C in contact with highly saline waters up to 271 g / l while improving phase permeability to oil;

- significantly reduced energy costs, time and labor.

The improved temperature resistance of the reagents used (preservation of the properties of the reagents in a wide temperature range from minus 45 ° C to 90 ° C), allows you to prepare the injected composition at any time of the year due to the low freezing temperature of the reagents and also the resistance of the reagents at high temperature. The factors listed above allow you to:

- it is more rational to use the energy of water injected into the reservoir as the main energy carriers (without increasing water injection);

- ensure coverage of oil-saturated formations by water flooding and increase in production due to the involvement of previously unrecoverable oil reserves in the development;

- extend the active development of deposits with increased final oil recovery.

The technical result of the treatment, ultimately, leads to a decrease in the water content of the produced products and an increase in oil recovery. The declared goals (tasks) are solved due to the claimed combination of features through the fact that the claimed technical solution is a resource-saving method for treating the formation.

The practical implementation of the tasks of the claimed technical solution is confirmed by the following examples.

Chemicals are injected sequentially and do not require a change of equipment. Based on geological conditions, with a high heterogeneity of the formation or the presence of highly permeable washed zones, at first in the flooded formation, due to changes in the volume of water injection into the wells, unsteady pressure is created and an aqueous flocculant solution is pumped. Then a solution of a synthetic crosslinking agent, a natural crosslinking agent, a multifunctional reagent and alcohol are pumped. If necessary, repeat the injection cycle.

The claimed method differs in that it is simple to perform, under favorable well conditions, it is possible to sell a multifunctional reagent and alcohol into the formation with or without a buffer, which significantly reduces energy costs, time and labor.

The method allows you to use the energy potential of the reservoir, i.e. use the energy released as a result of a decrease in interfacial tension to 0.005 mN / m and during phase transitions from a “hydrophilic” to a “hydrophobic” system, on the line of technophase contact of a formation using multifunctional reagents, which leads to an increase in oil recovery of formations with hard-to-recover reserves, for by providing the possibility of improving the separation and accelerating the promotion of hard-to-recover oil in the reservoirs, through the use (application) of a new composition, which allows to implement the method without increasing the water supply to the injection wells.

The volume of the prepared composition is determined based on the power of the treated formation, the radius of treatment, porosity and the coefficient of oil saturation of the formation according to the following formula:

Q = pR2HmKH,

where Q is the volume of the prepared composition, m ³ ;

R is the radius of processing, m;

N - power of the treated formation, m;

m is the porosity,%;

KN - coefficient of oil saturation of the reservoir;

p = 3.14.

The volume of the squeezing fluid for injection into the reservoir can be determined by the following formula: Q = QK-QHKT, where Q is the volume of the squeezing fluid, m ³ ; QK - column volume to the current face, m ³ ; QHKT - tubing string volume, m ³ .

As a squeezing liquid can be used:

- as anhydrous oil in a volume of 3-4 m ³ ,

- and water of varying degrees of mineralization.

Then continue to develop the reservoir in all modes of flooding. If necessary, repeat the download.

The effectiveness of the claimed technical solution is determined by the results of tests both on bulk linear models of the porous medium of the formation and on specific wells of the oil field and is evaluated, ultimately, by additional oil production and a simultaneous reduction in the volume of produced water.

Assessment of the technological effectiveness of the application of the chemical oil recovery method is carried out by measuring the following characteristics:

1. Additional oil production by increasing oil recovery, ie production with additional incremented extracted oil reserves.

2. The current additional oil production due to the intensification of fluid withdrawal from the reservoir.

3. Reducing the amount of produced water.

The basic option for the chemical method is the process of flooding oil reservoirs.

Field tests of the claimed method, carried out at several wells in the fields of the Udmurd Republic, are proved by the results obtained below.

Due to the application of the declared integrated energy-saving technology of EOR, the debit of oil wells increased by an average of 10%. Thus, the claimed method in comparison with known objects - analogues has a number of technological advantages, which are as follows:

- reducing the permeability of highly flooded layers;

- increasing the coverage of the reservoir with water during flooding, both in thickness and in strike;

- the involvement of low permeable oil rocks in the formation;

- an increase in the rate of phase interactions and the displacement of previously unrecoverable oil reserves while reducing both the volume of produced water and the discharge of water in general. The energy-saving flocculation system is characterized by improved thermal stability properties in a wide temperature range (from minus 45 ° C to 90 ° C) and chemical resistance of the applied chemicals and their compositions to mineralized waters (degree of mineralization up to 278 g / l).

The listed technological advantages of the claimed method make it possible to involve low-permeability layers in active development, to increase the pace of development and oil recovery of the reservoir without increasing the injected water.

Example 1

We performed the processing by the proposed method of the injection well of the Vyatka area of the Arlan field.

The study of the oil well revealed the following characteristics of the reservoir:

- reservoir terrigenous porosity from 12% to 25%;

- initial reservoir temperature 24 ° C;

- initial reservoir pressure of 12.1 MPa, on average;

- the viscosity of the oil in the reservoir of 24.1 MPa-s;

- the density of oil is 0.890 g / cm ³ ;

- gas saturation of 14.0 m ³ / t;

- total salinity of water 271.8 g / l g / m ³ (formation waters are brines of calcium chloride type);

- the average water cut of the extracted products in the experimental section was 95.3%;

- fluid production in the experimental plot of 429 m ³ / day;

- oil production - 37.2 tons / day.

At the same time, uneven flooding of producing wells along the most highly permeable interlayers and channels is observed in the indicated area. In order to increase Kohvat and Quit, sequentially alternating rims were pumped into the injection well. Example 1.1

a) composition 1) - water containing 0.001 wt.% polymer of polyacrylamide brand FP-307 (water 99.999 wt.%) volume of 500 m ³ ;

b) composition 2) - water containing 0.0001 wt.% natural crosslinking agent - PBMV grade bentonite clay powder (suspension), 0.001 wt.% synthetic crosslinking agent - AMG reagent (AMG-1 grade) (water - 99.9989 wt. .%) with a volume of 500 m ³ ;

c) a composition containing 50 wt.% multifunctional reagent brand ULTRAFLO commercial form 30 m ³ and 50 wt.% 1,2-ethanediol commercial form (with a volume ratio of 1) and ULTRAFLO reagent equal to 1: 0.06).

Example 1.2

a) composition 1) - water containing 1.5 wt.% polymer of polyacrylamide brand Praestol-2540 (water - 98.5 wt.%) volume of 500 m ³ );

b) composition 2) - water containing 10 wt.% natural cross-linking agent - bentonite clay powder grade PBMV and 0.15 wt.% synthetic cross-linking agent - reagent AMG (grade AMG-2) (water - 89.85 wt.%) volume of 500 m ³ ;

c) a mixture containing 99.9 wt.% multifunctional reagent brand ULTRAFLO commercial form 60 m ³ and 0.1 wt.% methanol commercial form (with a ratio of the composition 1) and ULTRAFLO reagent equal to 1: 0.12).

Example 1.3

a) composition 1) - water containing 3 wt.% polymer of polyacrylamide brand DP-9-8177 (water - 97 wt.%) volume of 500 m ³ ;

b) composition 2) - water containing 20.0 wt.% natural cross-linking agent - bentonite clay powder grade PBMV (suspension) and 0.3 wt.% synthetic cross-linking agent - reagent AMG (grade AMG-1) (water - 79, 7 wt.%) With a volume of 500 m ³ ;

e) a composition containing 0.1 wt.% multifunctional reagent brand ULTRAFLO commercial form 125 m ³ and 99.9 wt.% benzyl alcohol commercial form (with a ratio of volume 1) and ULTRAFLO reagent equal to 1: 0.25).

The process water was pushed in the volume of the production casing. Then, oil was sampled through the production well.

The total oil production rate in the pilot section after performing the above actions (treatment of the injection well by the claimed method) was 40.5 tons / day with a continuing effect.

Example 2

We performed the processing by the proposed method of injection wells of the Vyatka area of the Novoselkinskoye field.

The study of the oil well revealed the following characteristics of the reservoir:

- the reservoir is terrigenous;

- initial reservoir temperature of 240 ° C;

- initial reservoir pressure 13 MPa;

- on average: the viscosity of the oil in the reservoir of 24.1 MPa-s;

- the density of oil is 0.890 g / cm ³ ;

- gas saturation of 14.0 m ³ / t;

- total salinity of water 737.98 g / m3 (produced waters are brines of calcium chloride type);

- water cut in reservoir conditions of 93.3%.

A breakthrough of injected water into production wells occurred in a highly permeable layer.

Sequentially alternating rims were pumped into the well.

Example 2.1

The treatment was carried out by the claimed method of well No. X:

- at a depth of 1527.8-1533.8 m;

- porosity from 21.5% to 23%;

- throttle response 130 m ³ / day;

- injection pressure 84 atm .;

- water cut of products reached 94.7%;

- the total flow rate of oil wells decreased to 3.8 m ³ / day.

a) composition 1) - water containing 0.1 wt.% polymer of polyacrylamide brand FP-307 (water - 99.9 wt.%) volume of 500 m ³ ;

b) composition 2) - water containing 0.1 wt.% natural cross-linking agent - bentonite clay powder grade PBMV and 0.01 wt.% synthetic cross-linking agent - reagent AMG (grade AMG-2) (water - 99.89 wt. %) with a volume of 500 m ³ ;

c) a composition containing 50% by weight of a multifunctional reagent of the ULTRAFLO-M brand of a commodity form of 60 m ³ and 50% by weight of a desiccant-raw material manufactured in accordance with TU 2422-099-05766801-2000 (with a ratio of composition volumes 1) and ULTRAFLO -M is 1: 0.12).

Pouring process water is performed in the volume of production casing.

Then, through the production well, additionally extracted (residual) oil was selected.

After processing injection well No. X of the claimed method, the oil production rate averaged 5.9 m ³ / day. with continued effect.

Example 2.2

The treatment was carried out by the claimed method of well No. XX:

- at a depth of 1593.0-1601.0 m;

- porosity from 19.0% to 24.0%;

- pick-up 146 m ³ / day;

- injection pressure 60 atm .;

- water cut of products reached 93.3%;

- the total oil production rate of wells decreased to 5.2 m ³ / day.

To restore the flow rate, the source of watering and the flooded layer was determined, sequentially alternating rims were pumped into the injection well:

a) composition 1) - water containing 1.5 wt.% polymer of polyacrylamide brand FP-307 (water - 98.5 wt.%) volume of 500 m ³ ;

b) composition 2) - water containing 5.0 wt.% natural cross-linking agent - PBMV grade bentonite clay powder (suspension) and 0.3 wt.% synthetic cross-linking agent - AMG reagent (water - 94.7 wt.%) volume 500 m ³ ;

c) a composition containing 99.9% by weight of a multifunctional reagent of the RMD grade (grade RMD-3) of a commodity form of 30 m ³ and 0.1% by weight of bottom residues of rectification of dipropylene glycol (with a ratio of the volumes of composition 1) and RMD-3 equal to 1: 0.06).

Pouring process water is performed in the volume of production casing.

Then, through the production well, additionally extracted (residual) oil was selected.

The oil production rate after processing well No. XX averaged 7.8 m ³ / day with a continuing effect.

Example 3

The effectiveness of the displacement of residual oil is proved on bulk linear models of a porous medium, the primary displacement of oil from the reservoir was carried out by simulating production wells from the output of the models and injection wells from the input of the models with the following parameters:

- the length of the bulk part of the models is 100 cm;

- cross section of a porous medium of 3 cm;

- as the starting material for creating a porous medium, quartz sand of grinding fractions of 0.16-0.07 mm, with the addition of up to 10% calcium carbonate, fresh or mineralized water, oil from various deposits of Tatarstan, Udmurtia and Western Siberia is used;

- the temperature of the experiments is 20-90 ° C;

- injection and displacement of fluids from the porous medium of the model is carried out by a plunger pump, while recording the pressure drop created by the injection fluid;

based on the results calculated permeability values before and after processing the proposed method. The results of the experiments are evaluated by the following indicators:

1) reservoir resistance R at the end of the experiment;

2) the final coefficient of oil displacement of the reservoir;

3) the final residual oil saturation of the reservoir.

The change in the filtration properties of the porous medium is determined by the values of the mobility of water and the residual resistance factor. The residual resistance factor is defined as the ratio of the mobilities of the water that is filtered through the reservoir before and after the treatment of the model; in total, 6 experiments are carried out below. The sequentially alternating rims of the compositions were pumped in two cycles.

The research results of the injection of the proposed compositions and their sequences are shown in table Experience 1:

a) composition 1) - a solution containing, wt.%: PAA grade FP-307 0.3 and water 99.7, then a reservoir water buffer;

b) composition 2) - a solution containing, wt.%: 0.15 AMG-1 and 99, 85 water, then a reservoir water buffer;

c) composition 3) - water with a content of 6 wt.% bentonite powder (PBMB) and water - 94 wt.%, then - reservoir water buffer;

g) a composition containing: 50 wt.% reagent ULTRAFLO commercial form and 50 wt.% ethanol (with a ratio of volume 1) and ULTRAFLO reagent equal to 1: 0.25).

The indicated injection into a heterogeneous reservoir through an injection well in Western Siberia leads to an increase in Roct to 2.62 units. relative to water and increases the growth of the oil recovery coefficient in the reservoir to 26.8%, which is 1.7 times higher than the similar indicator of the prototype (experiment 6).

Experience 2.

Downloaded sequentially alternating rims in two cycles:

a) composition 1) - a solution containing, wt.%: 0.001 PAA grade DP 9-8177 and water 99.999, then - reservoir water buffer;

b) composition 2) - a solution containing, wt.%: 0.001 AMG-1 and 99.999, then - reservoir water buffer;

c) composition 3) containing, in wt.%: bentonite powder (PBMB) 3 and water 97, then a reservoir water buffer;

g) a composition containing: 99.9 wt.% RMD-5 and 0.1 wt.% 2-phenylethanol, (with a ratio of volumes of composition 1) and RMD-5 reagent equal to 1: 0.06).

With the indicated injection according to the proposed technology through an injection well of an inhomogeneous formation in the conditions of the Tatarstan fields, an oil recovery coefficient of 30.8% was obtained, which is 2 times higher than the similar indicator of the prototype (experiment 6).

Experience 3.

In the conditions of Udmurtia deposits, sequentially alternating injection in three cycles:

a) composition 1) - a solution containing, wt.%: 0.1 PAA brand Praestol-2540 and 99.9 water, then - reservoir water buffer;

b) composition 2) - a solution containing, wt.%: 0.05 AMG and 99.95 water, then a reservoir water buffer;

c) composition 3) - water with a content of 20 wt.% clay powder (water - 80 wt.%), then - reservoir water buffer;

g) a composition containing: 30 wt.% ULTRAFLO-M and 70 wt.% bottoms of rectification of dipropylene glycol, (containing 13.0-20.0 wt.% dipropylene glycol 34.0-40.0 wt.% tripropylene glycol, 22, 0-30.0 wt.% Tetrapropylene glycol, the rest is heavy protylene glycols) (with a volume ratio of composition 1) and ULTRAFLO-M reagent equal to 1: 0.1).

According to the proposed technology, an inhomogeneous formation through an injection well leads to an increase in oil recovery coefficient up to 28.6%, which is 1.8 times higher than the similar indicator of the prototype (experiment 6).

Experience 4.

In the conditions of Udmurtia deposits, it was pumped into a heterogeneous formation through an injection well by successively alternating rims in two cycles:

a) composition 1) - containing, wt.%: 3 water-swellable polymer brand VNP-1 and 97 water, then - reservoir water buffer;

b) composition 2) - a solution containing, wt.%: 0.3 AMG-1 and 99.7 water, then a reservoir water buffer;

c) composition 3) - water containing 13 wt.% kaolinite (water 87 wt.%), then - reservoir water buffer;

d) a composition containing: 90 wt.% of the ULTRAFLO commercial form and 10 wt.% methanol waste (methanol 57-58%, alcohols from the C2-C15 group the rest), with a volume ratio of composition 1) and ULTRAFLO reagent equal to 1: 0, 12,

which as a result led to an increase in the oil recovery coefficient in the reservoir of 24.7%, which is 1.56 times higher than the corresponding indicator of the prototype (experiment 6).

Experience 5.

In the conditions of Udmurtia deposits, sequentially alternating rims in two cycles were pumped into the heterogeneous reservoir through the injection well:

a) composition 1) - a solution containing, wt.%: 0.2 carboxymethyl cellulose grade CMC and 99.8 water, then a reservoir water buffer;

b) composition 2) - a solution containing 0.2 AMH and 99.8 water, then the reservoir water buffer;

c) composition 3) - water containing 15 wt.% purified montmolorillonite (water - 85 wt.%), then - reservoir water buffer;

g) a composition containing: 50 wt.% the commodity form of RMD-3 and 50 wt.% VAT residues of the production of ethyl carbitol (with a ratio of the volumes of composition 1 and reagent RMD-3 equal to 1: 0.25), which resulted in an increase oil recovery coefficient of the reservoir up to 25.4%, which is 1.6 times higher than the similar indicator of the prototype (experiment 6).

The parameters of the prototype are shown in experiment No. 6 of the table.

Thus, as a result of the performed experiments, it was shown that the claimed method of displacing residual hardly recoverable oil from waterlogged formations is more efficient compared to the prototype and is energy-saving, while the claimed technical solution (method + composition) allows its use both in terrigenous and in carbonate formations, to significantly improve the performance of the filtration resistance of the formation R and increase the final coefficient of oil displacement of the formation, while isolating highly permeable zones fins, to increase the coverage of the formation by exposure, both in thickness and along strike, to involve low-permeability layers in the work by using the energy of phase transitions in the reservoir conditions, can be used to increase oil recovery in a wide range of reservoir temperatures and mineralization of formation waters typical of Western deposits Siberia and the Ural-Volga region, significantly reduces energy costs, time and labor.

Analysis of the table below showed the receipt of the declared results, proving the achievement of the following 10 performance indicators of the claimed technical solution.

In experiment 1 (table) for the conditions of deposits in Western Siberia, performance indicators compared to the prototype were:

1. The increase in filtration resistance of the reservoir model is 2.62 units, which is 1.63 times or 63% higher than the prototype.

2. The increase in oil displacement coefficient in the reservoir is 26.8%, which is on average 1.65 times higher or 70%.

In experiment 2 (table) for the conditions of the deposits of Tatarstan, performance indicators compared with the prototype were:

3. An increase in the filtration resistance of the reservoir model is 4.53 units, which is 2.8 times or 183% higher than the prototype.

4. The increase in oil displacement coefficient in the reservoir is 30.8%, which is on average 1.94 times higher or 95%.

In experiment 3 (table) for the conditions of the deposits of Udmurtia, the performance indicators compared to the prototype were:

5. The increase in filtration resistance of the reservoir model 4.9 units, which is 3 times higher or 206% compared with the prototype.

6. The increase in oil displacement coefficient in the reservoir is 37.6%, which is on average 2.3 times higher or 138%.

In experiment 4 (table) for the conditions of deposits of Udmurtia, performance indicators compared with the prototype were:

7. The increase in filtration resistance of the reservoir model is 1.9 units, which is 1.2 times higher or 18.7% compared with the prototype.

8. The increase in oil displacement coefficient in the reservoir is 34.7%, which is on average 2.2 times higher or 120%.

In experiment 5 (table) for the conditions of the deposits of Udmurtia, the performance indicators compared to the prototype were:

9. The increase in filtration resistance of the reservoir model is 2.6 units, which is 1.62 times or 62.5% higher than the prototype.

10. The increase in oil displacement coefficient in the reservoir is 25.4%, which is on average 1.6 times higher or 60%.

Claims (1)

A method of increasing oil recovery, including sequential injection into the formation by cycles of at least two, divided into equal portions of polymer rims in water and a salt cross-linking agent in water with a water buffer between them, characterized in that AMG reagent is used as a salt cross-linking agent and additionally injection of clay agent rims in water and multifunctional reagent rims and aliphatic and / or aromatic alcohol, or production waste containing them, thereby reducing interfacial a lot of tension in the oil-water system to 0.005 mN / m, in the following sequence of rims and with their following compositions, wt.%:
1) 0.001-3 polymer in water
2) 0.0001-0.5 AMG in water
3) 0.0001-20 clay agent in water
4) a multifunctional reagent 0.1-99.9 and the indicated alcohol or the rest, with a ratio of the composition 1) and a multifunctional reagent equal to 1: (0.06-0.25)
or
1) 0.001-3 polymer in water
2) 0.0001-0.5 AMG and 0.0001-20 clay agent in water
3) a multifunctional reagent 0.1-99.9 and the indicated alcohol or the rest, with a ratio of the composition 1) and a multifunctional reagent equal to 1: 0.06-0.25.