RU2494136C1 - Surface-active acid composition for treatment of carbonate basins - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: surface-active acid composition for treatment of carbonate basins contains the following, wt %: hydrochloric acid (in terms of HCl) 6.0-24.0; alcohol-containing compound 5.0-30.0; surface-active substance - SAS, commercial washing agent "ZheniLen" 0.5-2.0; cationic surface-active substance - OksiPAV or Don-96 0.2-1.0; iron stabiliser 0.5-3.0; water is the rest.

EFFECT: intensifying oil production; providing compatibility of a treatment compound and a formation fluid even at available ferric iron in the quantity of 2000 ppm and more, stability to freezing at simultaneous preservation of property of retardation of speed of the reaction with carbonate rock.

3 cl, 2 tbl, 1 ex, 1 dwg

Description

The invention relates to the oil industry and can be used for acid treatment of the bottomhole formation zone to increase the intensification of oil production.

Known surface-active acid composition for processing the bottom-hole zone of wells, including a mixture of inhibited hydrochloric and hydrofluoric acids, a surfactant, a solvent of asphaltene-tar-paraffin deposits (ASPO) and water (RF Patent No. 2131972, 1998).

Also known is a surface-active acid composition for treating the bottom-hole zone of wells, including a mixture of inhibited hydrochloric and hydrofluoric acids, a surfactant, an ASPO solvent, hydroxyethylene diphosphonic acid (OEDP) and / or acetic acid and water (RF Patent No. 22439101, 2004).

These well-known acid formulations have shown high efficiency when used for processing bottom-hole zone of highly flooded and paraffin wells. However, it should be noted that during acid treatment of wells, there is a high probability of corrosion of the metal equipment of the well, as a result of which iron ions will enter the acid composition. And in the presence of a high concentration of iron in the acid composition or products of its neutralization with carbonate rock, as well as with repeated acid treatments or when using large volumes of reagent, the efficiency of acid treatment is sharply reduced due to the high rate of interaction of the composition with the rock of the carbonate formation and due to the formation of highly viscous interaction products composition and formation fluid, due to the presence of a large amount of iron.

Closest to the proposed technical solution is a composition for acidizing the bottom of the formation containing hydrochloric acid, an alcohol-containing compound, a surfactant, a surfactant, an iron stabilizer, and water (RF Patent No. 2379327, 2009).

The disadvantage of this known composition is the insufficient washing ability, in addition, the composition becomes inhomogeneous at ambient temperatures below 0 ° C, due to the limited solubility of its constituent alcohol-containing components at a given temperature.

In addition, the known composition does not fully provide compatibility with the formation fluid, especially when the content of ferric iron in an amount of more than 2000 ppm.

The technical result achieved by the present invention is to ensure compatibility of the composition and formation fluid even in the presence of ferric iron in an amount of 2000 ppm or more, resistance to freezing, while maintaining the property of slowing down the reaction rate with carbonate rock.

The specified technical result is achieved by the proposed surface-active acid composition for treating carbonate reservoirs, including hydrochloric acid, an alcohol-containing compound, a surfactant, a surfactant, an iron stabilizer and water, and according to the invention, the composition contains a technical detergent TMS “ZheniLen as a surfactant” "For the oil industry and cationic surfactants - OksiPAV or Don-96, with the following ratio of components wt.%:

hydrochloric acid (in terms of Hcl) 6.0-24.0 alcohol compound 5.0-30.0 indicated TMS "ZheniLen" 0.5-2.0 specified cationic surfactant 0.2-1.0 iron stabilizer 0.5-3.0 water rest

As an iron stabilizer, the composition contains hydroxyethylene diphosphonic acid or Trilon-B.

As an alcohol-containing compound, the composition contains lower alcohols, or glycols, or propylene glycols, or alcohol-containing waste products.

The achievement of the specified technical result is ensured, apparently, through the use of effective components that are well combined with each other, taken in the claimed ratio.

The introduction of the inventive acid composition of TMS "ZheniLen", which contains surfactants, a complexing agent, sodium silicate, flavoring, antifoam and water, provides an effective reduction in interfacial tension at the oil-composition interface, high washing properties and prevention excessive foaming.

And the additional introduction of a cationic surfactant: OxyPAS or Don-96, provides the formation of a surface-active complex (together with TMS ZheniLen), which unexpectedly in the presence of an iron stabilizer in the form of HEDP or Trilon-B leads to compatibility (eliminating the formation of persistent highly viscous products ) composition and formation fluid even with an increased presence of ferric iron in the composition - 2000 ppm or more (0.2 wt.% or more).

In this case, hydrochloric acid acts as an active principle, the required properties of which are provided by the above additives.

The inventive acid composition was investigated in laboratory conditions. The following substances were used for its preparation:

- inhibited hydrochloric acid (Hcl) 22-25% aqueous solution according to TU 2458-264-05765670-99;

- TMS ZheniLen according to TU 9144-006-502608930-2005 (pasty or liquid) (manufacturer of NPF PermKhimProdukt LLC);

- cationic surfactants:

- OksiPAV according to TU 2482-007-04706205-2006;

- Don-96 TU 2458-005-04706205-2004;

- iron stabilizers:

- OEDF according to TU 6-02-1215-81;

- Trilon-B according to GOST 10652-73 or according to TU 2642-001-33813273-97;

- alcohol-containing compounds:

- lower alcohols, for example, ethanol; isopropanol;

- glycols according to GOST 19710-83;

- propylene glycols, for example ethylene glycol according to GOST 19710-83;

- alcohol-containing industrial wastes, for example ethanol-methanol fraction according to GOST 2603-79;

- technical fresh water.

An example of the preparation of the proposed acid composition in laboratory conditions.

Example 1. 87.75 g of inhibited hydrochloric acid of 24% concentration was taken, 1 g of ZheniLen TMS, 0.25 g of DON-96, 1 g of HEDP and 10 g of glycol were added to it; the result was an acid composition with the following ingredients, wt.%: hydrochloric acid - 21.06 (in terms of Hcl); glycol - 10, TMS "ZheniLen" - 1, Don-96 - 0.25, OEDF-1, water-66.69.

An acid composition with a different component content was prepared in a similar manner.

During laboratory tests, the following properties of the proposed acid composition were determined:

1. Interfacial tension at the interface "acid composition - oil" on a stalagmometer according to the traditional method.

2. The formation of highly viscous products of interaction with oil by mixing equal volumes of oil and acid composition in the presence of ferric iron, as well as the formation of a residue on a sieve with a mesh size of 0.315 mm after filtering a mixture of oil and acid composition.

3. The rate of dissolution of carbonate rock. This value was estimated by the time of dissolution in an equal volume of the acid compositions of the marble cube with an edge equal to 1 cm.

The data on the formulation of the investigated acid compositions are shown in table 1. Data on the properties of these compounds are shown in table 2.

Table 1 No. p / p The components of the investigated acid compositions, wt.% Hydrochloric acid (in terms of Hcl) TMS "Zhenilen" for the oil industry Iron stabilizers Cationic surfactant Alcohol-containing compound Water one 6.0 2.0 1.0 Trilon-B 0.2 Hydroxy surfactant 5.0 glycol 85.8 2 20,0 1,5 1.5 OEDF 1.0 Don-96 10 ethanol-methanol fraction 66.0 3 24.0 0.5 3.0 OEDF 0.5 OxyPAS 15 ethanol 57.0 four 15.0 2.0 2.0 Trilon-B 1,0 OxyPAS 30 isopropanol 50,0 5. 17.55 1,0 1.0 OEDF 0.25 Don-36 10 Glycol 70,2 6. 23.0 0.5 3.0 OEDF - 15 ethanol 58.5 7. 20,0 - 1.5 Trilon-B 1.0 Don-96 10 em fraction 67.5 Prototype according to the patent of the Russian Federation No. 2379327 8 24-48 - 0.05-0.3 Lemon or oxalic acid 0.25-0.3 Syntanol ALM-7 or glycoil or diproxamine 157-65M 0.1-2.5 Polyvinyl alcohol 48.9-75.6

table 2 No. p / p No. of formulation of the composition of table 1 The properties of the investigated acid compositions Interfacial tension mN / m Compatible with formation fluid, sieve residue The rate of dissolution of the marble cube, g · m ² / hour one one 0.16 It does not form emulsions; insignificant sieve 3360 2 2 0.1 Does not form emulsions 4200 3 2 0.09 Does not form emulsions 4200 four 3 0.17 It does not form emulsions, the residue on the sieve is traces 2980 5 four 0.08 Emulsion and residue on the sieve does not form 2460 6 four 0.08 Emulsion and residue on the sieve does not form 2610 7 5 0.1 Emulsion and residue on the sieve does not form 3300 8 6 0.22 Viscous emulsion, partially filtered through a sieve 3060 9 7 0.19 Viscous emulsion, partially filtered through a sieve 3170 10 8 0.42 Viscous emulsion, not filtered through a sieve 3460 Note: 1. As a reservoir fluid, two classes of oil were used: light paraffin and heavy with a high content of asphaltenes and resins.
2. The content of ferric iron in the acid composition in experiments 3 and 5 of Table 1 was 2500 ppm, in the remaining 2000 ppm.

The results shown in tables 1 and 2 show that the proposed acid compositions have the following advantages over the known:

- characterized by high washing properties due to the low interfacial tension at the border "composition - oil";

- prevent the formation of highly viscous products when interacting with the reservoir fluid, ensuring their compatibility even in the presence of a high concentration of 2000 ppm and more than ferric iron;

- provide a slowdown in the reaction rate with carbonate rocks.

The impact of the proposed acid composition on the rocks of the reservoir is also studied on four samples of carbonate core with permeability: 42.7; 55.8; 58.3 and 39.8 MD. The dependence of the pressure of injection of acidic compositions into core samples on the number of pore volumes of the injected composition is shown in Fig. 1 (curve 1 - corresponds to the composition of the prototype; curves 2, 3 and 4 - to the proposed compositions 2, 3 and 4 from table 1 with the addition of trivalent gland).

The drawing shows that when filtering the proposed acid composition:

a) injection pressure increases to a lesser extent, and its breakthrough into the formation occurs after filtering a smaller volume of the composition. Thus, due to the increased washing ability, the filtering of the inventive composition into the oil-saturated part of the reservoir is facilitated.

b) getting into the claimed acid composition of ferric iron even in the amount of 2000 ppm or more does not adversely affect the filtering process through the carbonate core.

These advantages confirm the high efficiency of the claimed acid composition in solving problems of increasing the productivity of producing wells in reservoirs with a high content of carbonates and ferric iron.

Claims (3)

1. A surface-active acid composition for treating carbonate reservoirs, including hydrochloric acid, an alcohol-containing compound, a surfactant surfactant, an iron stabilizer and water, characterized in that the composition contains a detergent technical TMS "Zhenilen" for the oil industry and cationic surfactant - OksiPAV or Don-96 in the following ratio of components, wt.%
hydrochloric acid (in terms of Hcl) 6.0-24.0 alcohol compound 5.0-30.0 indicated TMS "ZheniLen" 0.5-2.0 specified cationic surfactant 0.2-1.0 iron stabilizer 0.5-3.0 water rest 2. The acid composition according to claim 1, characterized in that it contains hydroxyethylene diphosphonic acid or Trilon-B as an iron stabilizer. 3. The acid composition according to claim 1, characterized in that as an alcohol-containing compound it contains lower alcohols, or glycols, or propylene glycols, or alcohol-containing waste products.

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