RU2295635C2 - Oil production method - Google Patents

Abstract

FIELD: oil production industry, particularly to develop oil fields and to increase reservoir recovery at medium or later stage of development.

SUBSTANCE: method involves injecting acid containing composition and composition containing surfactant and liquid hydrocarbon in reservoir, wherein the acid containing composition additionally has rock reaction inhibitor, namely Zeolite or synthetic zeolite powder or syenite alkali-aluminum concentrate or industrial lignosulphonates or carboxymethylcellulose or Polycell carboxymethylcellulose or alumochloride or aluminum hydrochloride. All the components are taken in the following amounts (% by weight): acid - 97.5-99.9, above inhibitor - 0.1-0.25. The acid containing composition is injected before or simultaneously with composition containing surfactant and liquid hydrocarbon comprising 5-16 % by weight of surfactant and 84-95% by weight of hydrocarbon. Ratio between composition containing surfactant and liquid hydrocarbon and acid containing composition is 2-4. Above components are simultaneously injected in producing and injection wells.

EFFECT: improved reservoir recovery due to increased oil-sweeping factor and factor of reservoir coverage with action as a result of water-saturated and oil-saturated reservoir zone permeability regulation.

2 cl, 3 ex, 8 tbl

Description

The invention relates to the oil industry, in particular to methods for developing oil fields to enhance oil recovery at middle or late stages of development.

There is a method of developing an oil field by injection into the formation through an injection well between the rims of the water displacing agent - a composition containing an oil-soluble surface-active substance (surfactant), liquid hydrocarbon, GKZH and water (RF Patent No. 2065033, IPC E 21 V 43/22 , 08/10/1996).

The disadvantage of this method is the insufficiently high oil-displacing ability of the micellar solution and a slight decrease in the permeability of the water-saturated part of the formation, which significantly reduces the effectiveness of the impact.

There is a method of developing an oil field by injection into the formation through a well between the separating rims of oil displacing agent-composite system, including oil-soluble surfactant - Neftenol - NC, oil and water (RF Patent No. 2168617, IPC E 21 V 43/22, 2001 g.).

A disadvantage of the known method is the low efficiency of the method due to a slight increase in phase permeability to oil, which contributes to a limited increase in oil displacement and formation coverage factors.

The closest in technical essence is a method of processing the bottom-hole zone of a producing well by injecting an acidic microemulsion containing acid into the formation. After a technological pause, the solvent and the hydrocarbon solution of the hydrophobizing surfactant are sequentially pumped with the volume ratio of the acid microemulsion, the water-solvent and the hydrocarbon solution of the hydrophobizing surfactant (0.28-0.32) :( 0.95-1) (RF Patent No. 2023143, IPC E 21 V 43/22, 15.11 .1994 g.).

The disadvantage of this method is the low efficiency due to a slight increase in phase permeability for oil and rapid waterlogging of wells due to a significant increase in phase permeability in the water-saturated zone of the formation under conditions of highly permeable reservoirs, which contributes to an insufficient increase in the coefficients of oil displacement and reservoir coverage. In addition, the possibility of applying the method only in production wells and only with the permeability of reservoir reservoirs to 0.4 μm ² limits the scope of the method.

The objective of the invention is to increase oil recovery by increasing the coefficient of oil saturation and the coefficient of coverage of the reservoir by exposure as a result of the regulation of the permeability of water-saturated and oil-saturated zones of the formation.

The problem is solved in that in the method for extracting oil by injecting into the formation rims of an acid composition containing acid and a composition containing a surfactant and liquid hydrocarbon, according to the invention, the acid composition further comprises a moderator of the reaction with the formation rock — either Zeolite or crumb synthetic zeolites, or syenite alumina alkali concentrate, or technical lignosulfonates, or carboxymethyl cellulose - KMTS, or Polycell KMTs KMTs-9N, KMTs-9S, or alumochloride, or hydroxide aluminum chloride, in the following ratio of components, wt.%: acid 97.5-99.9, said moderator 0.1-2.5, the acid composition is injected before or simultaneously with a composition containing surfactants and liquid hydrocarbons at their ratio, wt.%: surfactant 5-16, liquid hydrocarbon 84-95, with a ratio of its volume to the volume of the acid composition from 2 to 4.

The method can be carried out simultaneously on production and injection wells.

Comparative analysis with the prototype allows us to conclude that the claimed method differs from the known one by the introduction of new criteria for the injectivity of the method, namely: before pumping the surfactant + liquid hydrocarbon composition, an acid composition is pumped in series or simultaneously with it, which contains acid and reaction inhibitors with the formation rock - or Zeolite, or a crumb of synthetic zeolites, or a syenitic alumina alkali concentrate, or industrial lignosulfonates, or CMC, or Polycell KMTs grade KMTs-9N, KMTs-9S, or aluminum chloride, il and aluminum hydroxyl chloride, with the following composition of components, wt.%: acid 97.5-99.9, said moderator 0.1-2.5, and a composition containing a surfactant and a liquid hydrocarbon has the following component composition, wt. %: Surfactant 5-16, liquid hydrocarbon 84-95, and the ratio of its volume to the volume of the acid composition from 2 to 4.

In addition, the proposed method can be carried out simultaneously on production and injection wells. Thus, the claimed invention meets the criterion of "novelty."

For the preparation of a composite system, Neonol AF 9-12 according to TU-2483-077-05766801-98, or Neonol AF 9-6 according to TU-2483-077-05766801-98, or Neftenol NZ according to TU 2483-007-17197708-93, or Neftenol NZb according to TU-2458-057-17197708-01, or surfactant OP-10 according to GOST 8433-81.

As liquid hydrocarbons in a composite system, liquid spent hydrocarbons (ZhOU) according to TU 38.303-05-27-92, Nefras AR-120/200 (solvent) according to TU 38.101809-90, Nefras A150 / 330 according to TU 38.1011049-87E can be used and other brands, crude oil, diesel fuel according to GOST 305-82, a wide fraction of light hydrocarbons according to TU 38.101524-83; hexane fraction according to TU-38.10381-83; fraction of aromatic hydrocarbons, toluene fraction according to TU-38.103579-85; nefras of various brands, etc.

For the preparation of the acid composition are used: hydrochloric acid technical according to TU 2122-205-00203312-2000 or hydrochloric acid inhibited according to TU 2122-131-05807-960-97, technical hydrofluoric acid according to GOST 2567-89, concentrated hydrofluoric acid according to TU 6- 09-2622-88, amend. No. 1-3.

Zeolite according to TU 381011366-94, or crumb of synthetic zeolites according to TU 2163-099-05766575-2000, or syenite alumina alkali concentrate according to TU 5726-047-00203938-97, or technical lignosulfonates are used as inhibitors of the reaction with the formation rock for preparing the acid composition (LST liquid production of Solikamsk PPM) according to OST-13-0281-036-06-89. Polycell KMTs of the KMTs-9N, KMTs-9S brand according to TU 2231-017-32957739-02, aluminum chloride according to TU 2152-106-05766575-2002; aluminum chloride according to TU 38.102163-84 or aluminum hydroxyl chloride according to TU 38.302163-94, or aluminum oxychloride is a waste product of isopropylbenzene production in accordance with TU 38-102-612-88.

The essence of the proposed method is as follows. When pumping an acid composition with additives to slow down the rate of reaction with the rock, by increasing the matrix of the reservoir, the phase permeability of the oil increases. When a composite system containing surfactant and liquid hydrocarbon is injected, a medium-phase system is formed - a hydrophobic emulsion, which, when filtered in a porous medium, mixes with wastewater and thickens and is structured in water-saturated channels of the formation with a gradual attenuation of the filtration process, helping to reduce water permeability due to the formation of an oil-water emulsion on the path of filtration, which leads to a redistribution of filtration flows and increased oil recovery. Filtration of the composite system into oil-saturated interlayers leads to the dilution of oil and its easier displacement from the reservoir. To increase oil production by increasing the coverage of the formation by exposure, the method can be carried out simultaneously on injection and production wells.

The technological process consists in injecting into the bottomhole zone through an injection or production well an acid composition simultaneously or sequentially with the addition of reagents to slow the reaction rate with the rock (aluminosilicates, lignosulfonates, CMC, etc.) and an emulsion-forming composition system based on a surfactant (neonol AF9- 12, AF9-6, Neftenol NZ, Neftenol NZb Neonols: OP-7, OP-10), liquid hydrocarbon (solvents, oil, diesel fuel, solvents, etc.).

The effectiveness of the proposed method was evaluated according to the results of laboratory and field experiments.

Example 1

Filtration is carried out in 2 stages through a model measuring 300 mm in length and 50 mm in diameter, filled with disintegrated quartz sand with a fraction of 0.05-1.2 mm with a residual oil saturation of 24% with an initial permeability of 1.010 μm ² . To saturate the model, oil with a viscosity of 13 cps is used. 0.3 pore volume of the acid composition is pumped through the oil-saturated model with the following composition of ingredients, wt.%: Hydrofluoric acid - 98: CMC-2; and after 12 hours, 1 pore volume of the emulsifying composition system is pumped with the composition of the ingredients, wt.%: solvent - 84; (Surfactant) neftenol - 16 and squeeze through wastewater (3 bp). Withstand 24 hours for a reaction. The degree of increase in oil phase permeability after injection of the acid composition, the residual oil saturation, the decrease in water permeability, and the increase in the oil displacement coefficient after injection of the composite system are determined. Similarly, experiments 2-7 were performed on the proposed method and experiment 8 on the prototype. The research results are shown in table 1.

The results of the experiments indicate that the phase permeability for oil after injection of the acid composition in experiments 1-7 increased by 2.9-3.5 times, after injection of the emulsion-forming composition, the water permeability decreased by 76.1-88.2%, then as in the prototype, an increase in oil permeability was not detected, and a decrease in water permeability was only 65.5%. The growth rate of displacement is 0.11-0.30, and the prototype of 0.06.

The results of similar laboratory studies during sequential filtering through reservoir models of compositions with different qualitative and quantitative component compositions using the above acids (hydrochloric), reaction inhibitors with formation rock (or zeolite, or lignosulfonates, or alumina chloride), liquid hydrocarbon (or oil, or nephras ) and surfactants (Neonol AF9-12, AF9-6) are shown in tables 2-4.

Example 2. Through an oil-saturated model 300 mm in length and 50 mm in diameter, filled with disintegrated quartz sand with a fraction of 0.05-1.2 mm with a residual oil saturation of 25% with an initial permeability of 1,050 μm ^2, 1 pore volume of the composition is pumped, with the following composition of ingredients , wt.%: hydrochloric acid - 25; lignosulfonates - 2.2; Surfactant (neftenol) - 9.1; liquid hydrocarbon (nefras) - 63.7 and push through 3 pore volumes of water. Withstand 24 hours for a reaction. The studied parameters (the degree of increase in phase permeability to oil, residual oil saturation, decrease in water permeability and increase in oil displacement coefficient) recorded during laboratory experiments 1-6 by the present method and experiment 7 by the prototype are shown in table 2.

The results of the experiments indicate that after the injection of the entire composition, the phase permeability in water in experiments 1-6 decreased by 68.5-87.2%, while according to the known method, the decrease in water permeability was only 61.0%. The growth rate of displacement is 0.12-0.31, and the prototype of 0.06.

The results of similar laboratory studies on filtering through a reservoir model a mixture of an acidic composition and a liquid hydrocarbon + surfactant composition with different qualitative and quantitative component composition using acids (or hydrochloric or hydrofluoric), moderators (or zeolite, or CMC, or aluminum chloride), liquid hydrocarbon (oil) and surfactants (or Neftenol NZ, or Neftenol NZb) are given in tables 6-8. In the experiments, all of these inhibitors were not used, for example, synthetic zeolite crumbs, alumina alkaline syenite concentrate, identical in chemical composition to the zeolite used, Polycell CMC grade KMTs-9N, KMTs-9C identical to that used in the CMC experiments, aluminum hydrochloride and alumina chloride .

The results of all laboratory experiments carried out indicate enhanced oil-displacing properties of the compositions used by the present method in comparison with the prototype.

Table 1 No. of experiments Residual oil saturation,% The content of components in the acid composition, wt. % Oil Permeability Growth Rate The content of components in the composition containing surfactant and liquid hydrocarbon, wt. % The ratio of the volume of surfactant + solvent: acid composition Decrease in permeability but to water,% The growth rate of displacement CMC Hydrofluoric acid Hydrocarbon solvent Surfactant (Neonol AF9-12) one. 30.7 2.0 98.0 2.9 84.0 16,0 3.0 71.1 0.11 2. 31.6 0.1 99.9 3.0 85.0 15.0 2,5 74.0 0.16 3. 30.1 0.3 99.7 3.2 87.0 13.0 2,8 76.1 0.18 four. 26.3 0.8 99,2 3,5 92.0 8.0 2.0 85.0 0.30 5. 19.5 2,3 97.7 3.3 93.0 7.0 2,5 87.0 0.25 6. 21.1 1.9 98.1 3,5 94.0 6.0 3,5 88.2 0.23 7. 23,2 2,5 97.5 3.9 94.7 5.3 3.0 86.9 0.22 Prototype. 65.5 0.06

table 2 No. of experiments Residual oil saturation,% The content of components in the acid composition, wt. % Oil Permeability Growth Rate The content of components in the composition containing surfactant and liquid hydrocarbon, wt. % The ratio of the volume of surfactant + solvent: acid composition Water permeability reduction,% The growth rate of displacement Zeolite Hydrochloric acid Oil Neonol AF9-12 8. 30.7 1,0 99.0 2,3 85.0 15.0 2.0 72,2 0.10 9. 31.6 2.9 97.1 3,5 94.7 5.3 4.0 87.0 0.21

Table 3 No. of experiments Residual oil saturation,% The content of components in the acid composition, wt.% Oil Permeability Growth Rate The content of components in the composition containing surfactant and liquid hydrocarbon, wt.% The ratio of the volume of surfactant + solvent: acid composition Water permeability reduction,% The growth rate of displacement Aluminum chloride Hydrochloric acid Nefras Neonol AF9-6 10. 29.9 1.3 98.4 2,4 94.5 5.5 2.0 71.5 0.12 eleven. 31.6 2,5 97.5 3.0 87.0 13.0 4.0 88.3 0.21

Table 4 No. of experiments Residual oil saturation,% The content of components in the acid composition, wt. % Oil Permeability Growth Rate The content of components in the composition containing surfactant and liquid hydrocarbon, wt.% The ratio of the volume of surfactant + solvent: acid composition Water permeability reduction,% The growth rate of displacement Lignosulfates Hydrochloric acid Oil Neonol AF9-6 12. 29.9 1,5 98.5 2,8 94.0 6.0 2,3 73.5 0.13 13. 31.6 2.6 97.4 3.3 85.0 15.0 4.0 89.2 0.24 Prototype. 65.5 0.06

Table 5 No. of experiments Residual oil saturation,% The content of components in the acid composition, wt. % The content of components in the composition containing surfactant and liquid hydrocarbon, wt.% The ratio of the volume of surfactant + solvent: acid composition Water permeability reduction,% The growth rate of displacement Lignosulfates Hydrochloric acid Oil Neftenol NZ one. 30.7 8.1 91.9 87.5 12.5 2.7 72.0 0.12 2. 31.6 16.5 83.5 87.5 12.5 2.9 73.3 0.14 3. 30.1 15.3 84.7 86.2 13.8 2.6 75.0 0.19 four. 26.3 10.8 89.2 91.9 8.1 2.2 82.0 0.31 5. 19.5 5.2 94.8 91.7 8.3 2,5 86.8 0.27 6. 21.1 8.5 91.5 93.5 6.5 4.0 87.2 0.28 Prototype. 61.0 0.06

Table 6 No. of experiments Residual oil saturation,% The content of components in the acid composition, wt. % The content of components in the composition containing surfactant and liquid hydrocarbon, wt.% The ratio of the volume of surfactant + solvent: acid composition Water permeability reduction,% The growth rate of displacement Zeolite Hydrochloric acid Oil Neftenol NZb 7. 29.6 7.7 92.3 87.3 12.7 2.6 71.5 0.10 8. 30.6 10.9 89.1 92.7 7.3 4.0 84.5 0.21 9. 31,0 15.9 84.1 87.4 12.6 3.0 75.0 0.19

Table 7 No. of experiments Residual oil saturation,% The content of components in the acid composition, wt. % The content of components in the composition containing surfactant and liquid hydrocarbon, wt.% The ratio of the volume of surfactant + solvent: acid composition Water permeability reduction,% The growth rate of displacement CMC Hydrofluoric acid Oil Neftenol NZb 10. 28.1 5.9 94.1 86.5 13.5 2,8 72.9 0.11 eleven. 31.6 13,2 86.8 90.9 9.1 3,1 78,2 0.14 12. 32,2 11.0 89.0 93.8 6.2 4.0 83.9 0.25

Table 8 No. of experiments Residual oil saturation,% The content of components in the acid composition, wt.% The content of components in the composition containing surfactant and liquid hydrocarbon, wt.% The ratio of the volume of surfactant + solvent: acid composition Water permeability reduction,% The growth rate of displacement Aluminum chloride Hydrochloric acid Oil Neftenol NZ 13. 29.0 7.7 92.3 89.9 10.1 2.6 71.3 0.13 fourteen. 32,3 12.7 87.3 89.6 10,4 3.2 80,4 0.15 Prototype. 61.0 0.06

Example 3. The object of the test is heterogeneous low-permeability carbonate reservoirs of the Kieselovsky horizon of the Tournaisian layer. The selected focus of exposure is represented by one injection and 3 producing wells. The average effective formation thickness is 4.8 m. The permeability of the formation is 0.11-1-0.100 μm ² . The average oil flow rate of the well is 0.7-1.8 tons / day, the water cut of the production of producing wells is 60.2-90.2%. The injectivity of the well 80 m ³ / day. Separately prepared in a measuring unit of the cementing unit by mixing an acid composition of hydrochloric acid of 15% concentration in an amount of 3.0 tons and aluminosilicates 0.02 tons and nonionic surfactants Neonol AF 9-12 - 0.02 tons. After a set of preparatory and research works the acid composition is pumped into the well, stopped for 12 hours, then the composition system is pumped from Neftenol NZ in the amount of 0.5 tons and the solvent of the liquid fuel oil is 6 tons. The composition of 16 m ^{3 of} wastewater is pressed into the formation. The well is stopped to respond for 24 hours and put into operation.

Over the course of 3 months, the water cut of the wells decreased to 63.3-86.5%, i.e. by 14.6%. Oil production increased to 2.0-4.5 tons / day, i.e. 2.5 times. According to the prototype, when the injection is carried out without preliminary injection of the acid composition, the oil production rate increased from 0.9 to 1.4, i.e. 1.5 times, and the water cut decreased from 87.1% to 82.7%, i.e. by 4.4%. As a result of a decrease in water cut and an increase in oil production per year from the application of the proposed method, 1,780 tons of oil were additionally extracted at the source of exposure, whereas the prototype only produced 450 tons. The injectivity of the injection well slightly increased from 80 m ³ / day to 86 m ³ / day.

Claims (2)

1. The method of oil recovery by injection into the formation of an acid composition containing acid and a composition containing a surfactant and a liquid hydrocarbon, characterized in that the acid composition further comprises a moderator of the reaction with the formation rock, or Zeolite, or synthetic chips zeolites, or syenite alumina alkali concentrate, or technical lignosulfonates, or carboxymethyl cellulose (CMC), or Polycell KMC grade KMTs-9N, KMTs-9S, or aluminum chloride, or aluminum hydrochloride in the following ratio and components, wt.%: acid 97.5-99.9, said moderator 0.1-2.5, the acid composition is injected before or at the same time as the composition containing surfactants and liquid hydrocarbons at their ratio, wt.%: surfactants 5-16, liquid hydrocarbon 84-95, with a ratio of its volume to the volume of the acid composition from 2 to 4. 2. The method according to claim 1, characterized in that they are pumped simultaneously into production and injection wells.