RU2351630C2 - Gas generating foam compound for treatment of bottomhole zone of formation (versions) - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil and gas industry, particularly to foam acid treatment of bottomhole zone of formation. The gas generating foam compound for formation bottomhole zone treatment contains, wt %: surface active substance SAS or mixture of SAS 0.1-3.0; water soluble polymer 0.1-5.0; dry organic acid 3.75- 20.0; nitrite of alkaline or earth metal 6.20-45.7; sal ammonia 4.79-35.4; high dispersive hydrophobic material 0.1-3.0; complexon 0.5-3.0; hydroxide of alkali metal 0.5-10.0; water - the rest. Gas generating dry acid foam compound for treatment of formation bottomhole zone contains wt %: SAS or SAS mixture 0.1-3.0; water soluble polymer 0.1-5.0; dry organic acid 3.75- 20.0; nitrite of alkaline or earth metal 6.20-45.7; sal ammonia 4.79-35.4; high dispersive hydrophobic material 0.1-3.0; complexon 0.5-3.0; hydroxide of alkali metal 0.5-10.0; weighting additive - the rest. The invention is disclosed in dependent patent claims.

EFFECT: increased efficiency of acid treatment of collectors due to improved flow characteristics of a compound, also due to reduction of rate of acid compound reaction with rock and to reduction of corrosion activity of the acid compound, due to raised efficiency of collector cleaning from mud solid particles owing to their flocculation; due to decreased rate of poorly soluble salts sedimentation and due to increased solubility of salt sediments on treated surfaces of collectors, due to washing properties of compound and hydrophobisation of collectors and also to improved oil-sweeping properties of the compound.

6 cl, 6 tbl, 5 ex

Description

The invention relates to the oil and gas industry, in particular to the field of acid foam treatment of the bottomhole formation zone, wedging out of the treated formations and reduction of scaling, and can be used for developing wells, new and old, after overhaul, as well as for killing wells, especially in fields with abnormally low reservoir pressure in the late stages of development.

Known gas-generating foam-forming composition containing in wt.%: Sodium nitrite 0.9-20.9; sulfamic acid 0.9-16.4; sulfamic acid neutralizing reagent 0.2-7.9; a foaming agent 0.1-2.5; water - the rest (patent of the Russian Federation No. 2197606, M. cl. 7 Е21В 43/22, ЕВВ 43/25, publ. 01.27.2003).

Known self-generating foam system containing urea, nitrite of an alkali or alkaline earth metal, acid, surfactant, urotropin and water (RF patent No. 1273508, CL EV 43/00, 1988).

Known foaming composition containing in wt.%: Nitrite of an alkali or alkaline earth metal 12.1-58.7; ammonium chloride 2.4-41.0; ammonium hydrodifluoride 2.4-24.3; dispersant-stabilizer foam 0.1-1.5; water - the rest (RF patent No. 2085567, class 6 CO9K 7/08, EV 43/25).

Known foaming composition containing in wt.%: Urea 10.4-10.7; alkali or alkaline earth metal nitrite 59.0-60.7; Lewis acid 23.7-24.4; foam stabilizer 0.1-1.3; Surfactant 0.4-0.8; water - the rest (RF patent No. 20476540, class 6, C09K 7/08, EV 43/25, publ. 10.11.1995).

Known solid foaming agent, containing in wt.%: Powder lignosulfonate 42-57, block copolymers of propylene and ethylene oxides 28-42; carboxymethyl cellulose 2-28, the iron complex of the monosodium salt of ethylenediaminetetraacetic acid 1-4 (RF patent No. 2069682, CL 6 C09K 7/08, publ. 11/27/1996).

Known solid foaming agent containing in wt.%: Nonionic surfactants 25-27, a complex salt of urea with an acid of 25-48; nitrites of alkali or alkaline earth metal 18-27 (RF patents No. 2100577, cl 6 Е21В 43/00, Е21В 37/00).

The main disadvantage of the known formulations mentioned above is the insufficient efficiency of recovery of reservoirs in the bottom-hole formation zone due to their low wedging and low solubility of salt deposits on the treated surfaces of the reservoirs and low oil-displacing properties of the compositions.

The closest in composition is a foaming composition containing in wt.%: Ammonium chloride 30.0-35.4; alkali or alkaline earth metal nitrite 38.8-45.7; alkali metal or alkaline earth metal halide 11.2-22.5; CMC or PAA 0.3-0.8; Surfactant 0.04-0.50; water - the rest (RF patent No. 2047639, cl 6 C09K 7/08, publ. 10.11.1995).

The aim of the invention is to increase the efficiency of acid treatment of reservoirs by improving the rheological properties of the composition, reducing the reaction rate of the acid composition with the rock and its corrosive activity, increasing the efficiency of cleaning collectors of clogging solid particles by floculating them, reducing the rate of deposition of sparingly soluble salts and increasing the solubility of salt deposits on the treated surfaces of the collectors, increasing the washing properties of the composition and hydrophobization of the collectors, as well as lichenie oil-displacing properties of the composition.

This goal is achieved in that the gas-generating foam composition for treating the bottom-hole formation zone, containing a surfactant surfactant or a mixture of surfactants, a water-soluble polymer, a reaction initiator, ammonium chloride, an alkali or alkaline earth metal nitrite and water, is characterized in that it contains as an initiator dry organic acid and additionally highly dispersed hydrophobic material, alkali metal hydroxide complex, in the following ratio of components, wt.%:

Surfactant or surfactant mixture 0.1-3.0 Water soluble polymer 0.1-5.0 Dry organic acid 3.75-20.0 Alkali nitrite or alkaline earth metal 6.20-45.7 Ammonium chloride 4.79-35.4 Fine hydrophobic material 0.1-3.0 Complexon 0.5-3.0 Alkali metal hydroxide 0.5-10.0 Water rest

2. The composition according to claim 1, characterized in that it further comprises a crosslinker - a salt of a polyvalent metal in an amount of 0.01-0.2 wt.%.

3. The composition according to claim 1, characterized in that it contains dry organic acid - monochloracetic acid MHUK and additionally - sodium salt MHUK in the range of ratios MHUK: sodium salt MHUK as 4: 1-2: 1.

4. Gas generating dry acid foam composition for treating the bottomhole formation zone, containing a surfactant surfactant or a surfactant mixture, a water-soluble polymer, a reaction initiator, ammonium chloride, an alkali or alkaline earth metal nitrite, characterized in that it contains a dry organic acid, additional weighting agent, highly dispersed hydrophobic material, complexon and alkali metal hydroxide in the following ratio of components, wt.%:

Surfactant or surfactant mixture 0.1-3.0 Water soluble polymer 0.1-5.0 Dry organic acid 3.75-20.0 Alkali nitrite or alkaline earth metal 6.20-45.7 Ammonium chloride 4.79-35.4 Fine hydrophobic material 0.1-3.0 Complexon 0.5-3.0 Alkali metal hydroxide 0.5-10.0 Weighting compound rest

5. The composition according to claim 4, characterized in that it further comprises a crosslinker - a salt of a polyvalent metal in an amount of 0.01-0.2 wt.%.

6. The composition according to claim 4, characterized in that it contains dry organic acid - monochloracetic acid MHUK and additionally - sodium salt MHUK in the range of ratios MHUK: sodium salt MHUK as 4: 1-2: 1.

Anionic surfactants are used as water-soluble surfactants, for example, surfactants of the Sulfonol NP-1 and Sulfonol NP-3 brands, produced by Avangard Production Association, Sterlitamak and Ikar Scientific Production Enterprise, Ufa (Ufaneftekhim JSC), CJSC “Bursintez-M”, or sulfonates of different grades, for example, Sulfonate (SNA) according to TU 6-00-763450-86-89 or refined alkylarylsulfonate paste (RAS) according to TU 38.602-22-19-90, as well as water-soluble nonionic surfactants, for example, nonylphenol, ethoxylated with 12 moles of ethylene oxide (AF ₉ -12), manufactured according to TU-2483-077-05766801-98 at OAO Tatneft, or its commercial form CHO-3.4, either nonionic surfactants of the OP-7, OP-10 or OP-20 brand, or a mixture of anionic and nonionic water-soluble surfactants, for example, Neftenol VVD according to TU 2483-015-17197708-97 or Neftenol ML according to TU 2481-056-17197708-00, or VKS Neftenol in accordance with TU 2483-048-17197708-99, or K-surfactant Neftenol for acid treatments, manufactured by Khimeko-Gang CJSC, or MBP-M-100 grade buffer fluid based on polyphosphates (GMFN and TPFN up to 0.5 %) or neonol AF-12 or AF-25 (up to 0.5%), produced by NPO Burenie, or Oksifos KD-6 or Oksifos B - phosphate-containing anionic surfactants, water-soluble cationic surfactants of the IVV-1 or Katapin brands (brands A , K CI) amine modifier AM-1 grade.

In addition, as a surfactant for treating bottom-hole zones of injection wells, mixtures of water-oil-soluble surfactants are used in the form of ready-made compositions, for example, detergents ML-80, or ML-81B (winter version of ML-80) containing a mixture of a water-soluble anionic surfactant ( 23-28%) and non-ionic oil-soluble surfactants (12% by weight) produced in accordance with TU 2481-007-50622652-99-2002 at ZAO NPF Bursintez-M or a new detergent preparation of the ML-Super brand manufactured by " Delta-prom "in Samara, according to TU 2383-002-51881692-2000, as well as surfactants of PDK-515 grade based on N AB and the nitrogen-containing additive sold Urusinskim pilot plant "Soihneftepromhim" or nonionic surfactant marks Prevotsel, proxanol, Separol or Sintanol DT 7 Sintanol CP-10 or OC-20 formulation.

As a water-soluble polymer, a water-soluble polymer of the Aquapack brand is used, manufactured by Polycel CJSC under license from Aqulon (France) or a VPK-402 flocculant according to TU 2227-184-00203312-98, or VPK-420, or Gipan, or Givpan, according to TU 01-166-77, or the domestic Metas brand polymer for regulating the filtration and flocculation of the solid phase, or the powdered reagent GOS-2, or hydroxyethyl cellulose (HEC), or a complex of block copolymers with nonionic surfactants, or biopolymers based on glucose, mannose, salt gluconic acid and acetyl radicals, not sensitive high temperature - a heteropolysaccharide of the GPS brand or a polymer mixture of derivatives of polysaccharides of the brand Polymer reagent PS, or a block copolymer of ethylene oxide and nonionic surfactants of the brand Disolvan, or a block copolymer of ethylene oxide with nonionic surfactants, or the product of the interaction of alkaline cellulose with monochloracetic acid (CMC 500) KMTS 500 KMTS KMTs-600, KMTs-700, or Lacris-20 multifunctional polyacrylic reagent, manufactured according to TU 6-01-2-793-86, or methacrylic acid copolymer or methacrylamide metacrylamide, or MTs brand methyl cellulose, or ethoxylated c cellulose of the OEC brand, or hydroethyl cellulose of the SCE and its modifications, or polyacrylamide of different brands, for example, PAA, as domestic production, for example, PAA, manufactured according to TU 6-01-1049-91 and low molecular weight PAA, grade AK-642 with MM 1,0 -1.5 x 106 and a degree of hydrolysis of 5-10%, manufactured in accordance with TU 6-0202-00209-912-65-99 FSUE Saratov Research Institute of Polymers of the city of Saratov, and imported, for example, an anionic polymer of the brand EZ-mud DP, analog PAA, or a polymer of the Didril brand manufactured in Japan, or polyvinyl alcohol, or a polymer of the Polytsel brand SK-N, manufactured according to TU 2231-001-329577 39-98, or modified lignosulfonates of sodium carboxymethyl cellulose of the Politsel KMTs-M and Politsel KMTs-TS brands, or high viscosity polyanionic cellulose of the Politsel PACs brand, produced according to TU 2231-013-32957739-00.

As dry organic acid, monochloracetic acid, which is a non-deficient product produced in large volumes, is more often used. In addition, other dry weak organic acids are used having a low rate of interaction with carbonates and a low corrosive ability of oil equipment, for example, trichloroacetic, iminodiacetic, citric or oxalic acids.

Monochloracetic acid (MCA) CH ₂ ClCOOH is a colorless crystalline substance with a melting point of 61.2 ° C and a bp of 189.3 ° C, soluble in water, alcohol, acetone, and ether. It is produced in Ufa UGPP Khimprom according to TU 6-01-13-90.

Trichloroacetic acid (TCA) CCl ₃ COOH is a colorless crystalline substance with a melting point of 59.2 ° C and a bp of 197.6 ° C, soluble in water, alcohol, acetone, and ether. It is produced in Ufa UGPP Khimprom according to TU 6-01-13-90.

Citric acid (C ₆ H ₈ O ₇ ) (lim. Acid) - tribasic acid (2-hydroxy-1,2,3-propane-tricarboxylic acid) - a colorless crystalline substance with a melting point of 153 ° C, solubility in water at 25 ° C is 133 g in 100 g of water.

N, N - iminodiacetic acid (IDUK) - a white hygroscopic crystalline substance, non-toxic, odorless, readily soluble in water.

Oxalic acid - NOOS - COOH (char. To-that) - dibasic carboxylic acid - colorless crystalline substance with a melting point = 189.5 ° C, solubility in water at 20 ° C is 10 g in 100 g of water, at 100 ° C - 120 g is a non-deficient product.

As a finely dispersed hydrophobic material, finely dispersed hydrophobic materials of tetrafluoroethylene (TFE), oxides of titanium, iron, chromium, zinc, aluminum, polyvinyl alcohol (PVA), as well as highly dispersed hydrophobic materials of silicon oxides, such as soot, talc, aerosil, are chemically modified on the surface. perlite, as well as silica brand Polysil.

The above highly dispersed hydrophobic materials are chemically inert materials with an average individual particle size of from 0.1 to 100 μm and a bulk density of 0.1 to 2.0 g / cm ³ , with wetting angles of 114 to 178 ° and a degree of hydrophobicity of 96.0 to 99.99%. They do not have harmful effects on humans and the environment.

Chemically modified silicas (SiO ₂ ) are used as Polysil and, depending on the modification method, hydrophobic (Polysil-P1) and diphilic (Polysil-DF) are used.

Polysil is a trademark of chemically modified silicas (SiO ₂ ) (Trademark "Polysil", certificate No. 199999 of December 6, 2000).

As chelator used aminopolycarboxylic acids and their derivatives, for example, nitrilotriacetic acid (NTA) or ethylenediamine tetraacetic acid (EDATUK) or the disodium salt of ethylenediaminetetraacetic acid (NAM EDATUK) and dietilentriaminpentouksusnuyu acid (DETAPUK) or trans-1,2-diamintsiklogeksatetrauksusnuyu acid (DATsGTUK).

In addition, complexons with phosphonic groups are used, for example, hydroxyethylidene diphosphonic (OEDP), hydroxypropylene diamine tetramethylene phosphonic (DTP) and nitrilotrimethylene phosphonic (NTP) acids.

As gassing agents, nitrite of an alkali or alkaline earth metal and ammonium chloride are used.

Polyvalent metal salts are used as a crosslinker — trivalent salts, for example, acetates, chlorides, nitrates, chromium, aluminum citrates, potassium chromium alum (CCC), chromium alum waste (OHC), and also salts in oxidized form, for example chromates, dichromates .

The sodium salt of monochloracetic acid (sodium salt of MCCA) - CHNaClCOOH - a colorless crystalline substance soluble in water, alcohol, acetone, ether, is available in Ufa UGPP "Khimprom" according to TU 6-01-13-90.

Sodium and potassium hydroxides are used as alkali metal hydroxide.

Sodium hydroxide is a technical brand of RD, the highest grade, is produced according to GOST 2263-79 TATNIPIneft OAO Tatneft, Bagulma.

When processing the bottom-hole zone of the formation, gas-generating foamy acid compositions are used to increase the efficiency of recovery of reservoir permeability, which can significantly improve the quality of the treatments and significantly increase their technical and economic indicators.

Bottom-acid treatments of the bottom-hole formation have an advantage over conventional acid treatments.

When treating the bottom-hole zone with acidic foam compositions, the reaction rate with the carbonates of the reservoir surfaces decreases due to a decrease in the contact surface of the acid foam with the rock and its penetration into the formation matrix.

The use of effective foam formulations for treating the bottom-hole zone of the formation reduces the recovery time of the permeability of mud-clogged reservoirs by cleaning their surface by increasing the dissolution of poorly soluble salts and reducing salt deposition on the surface of the reservoirs, as well as by increasing the clayiness of the treated reservoirs, thereby increasing the overhaul period of their work in 3-4 times.

In addition, by increasing the oil-displacing properties of the composition, the productivity of wells increases by 1.5-2 or more times.

Unlike the prototype, the proposed gas-generating foam composition additionally contains a highly dispersed hydrophobic material (WGM), complexon, alkali metal hydroxide and a weighting agent (in checkers), and an organic acid as a reaction initiator.

Highly dispersed hydrophobic material (WGM) of the above grades is introduced into the proposed foam composition in an amount of 0.1-3.0 wt.%.

As a result of fixation in the pore volume due to the fine particle size, the VDGM increases the hydrophobization of the pore channels, due to which the contact angle increases and the capillary pressure at the water / oil interface decreases. As a result of hydrophobization of the pore surface, the amount of capillary-pinched water in them decreases during both absorption and drainage, which contributes to a more complete restoration of the phase permeability of oil.

A highly dispersed hydrophobic material, penetrating into the pores of the reservoirs, prevents the swelling of clay silicate minerals and reduces the colmatation of the reservoirs, as it prevents the formation of silica gels, which are the product of the reaction of acid with cement stone.

Introduction VDGM in the proposed foam composition allows to obtain a three-phase foam, which differs from two-phase foam by the presence of a solid phase, the presence of which significantly increases the stability of the foam composition. It is known that the stability of three-phase foam is much higher than two-phase.

VDGM is an effective foam stabilizer, as it increases the strength and durability of the foam film skeleton and allows to obtain more viscous (gel) structures. This helps to improve the structural parameters of the foam composition, capable of maintaining a strong foam structure for a long time. This leads to an increase in the thermal stability of the composition in the strata to 100-150 ° C.

The stabilization of three-phase foams is associated with mechanical hardening of the foam films as a result of their booking by particles of the solid phase. This can occur even when fine particles are not enough to completely cover the bubbles.

Variants of the proposed foam composition further comprise complexon, alkali metal hydroxide and weighting agent. All of these components are electrolytes that significantly increase the stability of the foam. Obviously, foam stabilization is due to the complexing ability of electrolytes.

The effectiveness of the use of the complexones listed above is that they form, with many cations, slightly soluble weakly dissociated complex compounds in water.

It is especially important that the weakly dissociated complex compounds bind cations that form hardness salts, for example, salts of Ca ²⁺ Mg ²⁺ cations and other cations, for example, Fe ³⁺ cation, which forms hydroxides, which often precipitate on the surface reservoirs and in the pores of the reservoir.

As a result of using complexon, the solubility of formation water salts increases and the salt deposition on the treated surfaces of the collectors decreases. In addition, the solubility of salt deposits on the treated surfaces of the collectors increases.

Barrier, calcium, potassium or sodium salts, for example nitrates or chlorides, are used as a weighting agent.

The following dry organic acids are used as the initiator of the gas-formation reaction: monochloracetic (MCC), trichloroacetic (TCA), iminodiacetic (IDA), citric (lim.k-ta) or oxalic (sch.k.-ta).

The above dry weak organic acids, in contrast to strong mineral acids, have a lower rate of neutralization, therefore, they have a low activity when exposed to the rock, unlike most inorganic acids.

In addition, these dry acids do not cause corrosion of equipment and they are effectively used in foam compositions injected at both low and high temperatures of the formation.

The proposed foam composition contains the above surfactants surfactants or a mixture of surfactants and a water-soluble polymer, as well as a crosslinker to obtain a crosslinked gel (polymer with cross-bonds) - foam.

The proposed gas-generating foam composition is formed due to the release of free gas (nitrogen) as a result of the chemical reaction of the blowing agents and dissolution of the surfactant.

The main characteristics of the foam composition are the multiplicity of the foam and its stability (stability).

The multiplicity of the foam depends on the amount of gas and the concentration and nature of the surfactant, polymer and other components. The multiplicity of the foam is the ratio of the volume of the initially formed foam to the volume of the foaming liquid.

The stability of the foam is characterized by the lifetime of the foam, which is determined by the time during which 50% of the foaming liquid is released from the foam, that is, when the structural and rheological properties of the foam are still preserved.

The main factors that affect the stability (foam lifetime) of the foam composition are the surface activity of the blowing agent, the concentration of the blowing agent and the presence of a stabilizer.

To obtain a foam with a long lifetime, it is necessary to strengthen the structure of the foam frame created by the foaming agent (nitrogen gas and surfactant), that is, the foam needs to be stabilized, the foam composition must be stabilized with the help of a water-soluble polymer and other components.

As surfactants use surfactants of anionic type, such as sulfonol NP-1 or sulfonol NP-3, or sulfonate (SNS) or refined paste grade PAC, as well as nonionic surfactants: ethoxylated alkyl phenols, e.g., nonylphenol - AF ₉ - 12, or a commercial form СНО-3,4, or nonionic surfactants of the OP-7, OP-10 or OP-20 grades, or polyoxyethylene glycol ethers of synthetic primary fatty alcohols of surfactants Sintanol and surfactants of the other brands mentioned above.

Anionic surfactants are best used in a mixture with nonionic surfactants, since surfactants are salted out in contact with alkaline earth metal salts, which are typical representatives of produced formation waters.

In the proposed foam composition, a mixture of the aforementioned ACAS and nonionic surfactants is used in a 2: 1 ratio or ready-made compositions of mixed surfactants, for example, grades ML-80, ML-81B or ML-super, which use approximately the same ratio of surfactants and nonionic surfactants. With such a ratio of surfactants and nonionic surfactants, anionic surfactants do not salted out even in formation water of high salinity (270-300 g / l).

To improve the rheological and flocculating properties of the proposed composition, the above polymer reagents are used, which have chemical stability, maintain high viscosity characteristics with increasing temperature, are compatible with other reagents in the composition, and are technologically advanced in preparing the composition.

As a water-soluble polymer for thickening the acid composition, PAA is used as a domestic production, for example, PAA produced in accordance with TU 6-01-1049-91 in the form of a powder and in the form of granules with an MM higher than 10 ⁷ and heat resistance up to 130 ° C, and a low molecular weight PAA grade AK-642 with MM = 1.0-1.5 × 10 ⁶ and a degree of hydrolysis of 5-10%, as well as imported polymers, for example, an anionic polymer of the EZ-mud DP brand, an analogue of PAA, is heat-resistant up to 150 ° C, anionic polymers cellulose series - КМЦ-500, КМЦ-600, КМЦ-700, ГЭЦ - hydroxyethyl cellulose, МЦ - methyl cellulose, ОЭЦ - hydroxyethylated cellulose, polyvinyl alcohol (PVA), PS polymer reagent - a polymer mixture of polysaccharide derivatives, heat-resistant up to 150 ° C, Polycel brands and other polymers mentioned above.

The macromolecules of the polymer contained in the proposed foam composition flocculate the clogging particles, which prevents them from settling in the formation.

The heat resistance of the solutions of the above polymers introduced into the proposed composition increases the heat resistance of the proposed foam composition.

It is known that foams are obtained by dispersion and condensation methods. The formation of foam as a result of a chemical reaction, accompanied by the release of gaseous products, refers to the condensation method of obtaining it.

The general scheme for the interaction of gas-forming reagents is as follows:

nNH ₄ Cl + Me (NO ₂ ) n = nN ₂ + NaCl + 2H ₂ O, where

Me is an alkaline or alkaline earth metal, n is the index of the chemical formula of a molecule of a substance.

The use of chemical reactions in the interaction of which nitrogen is released is the most promising.

Compared to carbon dioxide, ammonia, methane or acetylene, nitrogen generation is more preferable, since nitrogen is an inert gas and its solubility in water is 50-70 times less than the solubility of carbon dioxide in the range from 0 ° C to 60 ° C and more than 2 times less solubility of methane - the main component of natural gases.

Nitrogen-containing foam has its advantages: firstly, it has a higher gas saturation ability due to the low solubility of nitrogen in water, in contrast to carbon dioxide, ammonia or methane, especially at high pressure. Secondly, nitrogen-containing foam has a low corrosive ability of oilfield equipment.

To adjust the pH of the composition in order to reduce equipment corrosion, you can use a buffer mixture - a mixture of a weak organic acid and the sodium salt of this acid or a mixture of a weak organic acid and a strong base,

To do this, in the inventive composition, either a mixture of monochloracetic acid MCCA with the sodium salt of MCCA, or a mixture of MCCA or another of the above dry organic acids and alkali metal hydroxide is used as a buffer mixture.

The studies were carried out using the weight ratio of MCCA to the sodium salt of MCCA in the range of 5: 1-1: 1, and the weight ratio of MCCA or another of the above dry organic acids and alkali metal hydroxide in the range of 8: 1-1: 1.

The concentration of hydrogen ions (pH) depends on the quantitative ratio of MCAA and its sodium salt, or MCAA or other of the above organic acids and sodium hydroxide in the above range of ratios.

It is known that adjusting the pH of the medium (pH greater than 4): maintaining a pH in the range of pH = 4-6 prevents the formation of nitrogen dioxide (brown gas) having high corrosive activity, and as a result, the life of oilfield equipment is increased due to a decrease in its corrosion .

The degree of dissociation of a weak acid, for example, MCA, decreases with the addition of a salt of this acid, the sodium salt of MCA. By varying the concentration of MCA and its sodium salt, one can obtain solutions with different pH.

For example, by increasing the weight ratio of the amount of sodium salt of MHK in a mixture of MHK with the sodium salt of MHK in the range from 5: 1 to 1: 1, we thereby reduce the concentration of hydrogen ions in the claimed composition.

To obtain a buffer mixture of MCA or other of the above weak organic acids and a strong base, sodium hydroxide or potassium hydroxide is added to the inventive composition. The difference in the use of sodium or potassium hydroxides is only in quantitative proportions, which are calculated by the equation of the chemical reaction.

As a result of studies, it was found that MCCA and Na-salt of MCCA are better used in the range of weight ratios of 4: 1-2: 1, and MCCA or other above-mentioned dry organic acids and alkali metal hydroxide in the range of weight ratios of 7.5: 1-2 :one.

In the proposed foam composition, a mixture of a weak acid and a salt of this acid or a mixture of a weak acid and a strong base (analogue of the classical acetate buffer solution) are used as a buffer solution, namely, a mixture of MCAA + Na-salt MCAA or MCAA or trichloroacetic, iminodiacetic, citric, oxal or sulfamic acid + NaOH = Na-salt of MCC or a salt of the other of the above acids + H ₂ O.

The concentration of hydrogen ions (pH) in the composition of the composition depends on the concentration of MCA or other organic acid and the degree of its dissociation.

The mechanism of action of alkali metal hydroxide and its effect on the change in the acidity of the composition can be explained as follows.

The alkali hydroxide ions will be linked to hydrogen ions of a weak organic acid according to the equation of reaction in undissociated water molecules. A decrease in hydrogen ions shifts the reaction equilibrium to the right, towards the formation of new hydrogen ions. As a result of the reaction, the salt concentration increases, while the degree of dissociation of a weak organic acid decreases slightly, very slightly.

When diluted with water of the proposed foam composition, the pH of the composition practically does not change.

The decrease in corrosion activity of the proposed foam composition compared with known compositions, including the prototype, is confirmed by experimental data.

When determining the corrosivity, we used the research method for weight loss by the difference in weight of the samples before and after immersion in an aggressive environment.

From the data table. 1 it is seen that the proposed foam composition has a low corrosion activity and will help reduce equipment corrosion.

Variants of the proposed foam composition include the use of an aqueous foam composition and a dry acid composition in the form of dry checkers.

The content of the components in the compositions of the claimed aqueous foam composition, the composition of the prototype and their properties are shown in table 2-4.

Studies have been conducted on the selection of optimal sizes of checkers: their diameter and height.

The density of the drafts and the density of the liquid (produced water) in which they are deposited, and the size of the drafts, affect the speed of movement of the drafts (the speed of their deposition).

The studies were carried out on the following installation, which was a plastic pipe 2400 mm long (2.4 m) and an inner diameter of 42 mm (4.2 cm). The plastic pipe was installed strictly vertically along a plumb line. The lower end of the pipe was hermetically connected to a glass conical flask. To eliminate wall effects that reduce the speed of movement of the pieces, the inner diameter of the pipe was chosen so that it significantly exceeded the diameter of the studied pieces.

During the experiments, the pipe was filled with water of various densities, which was regulated by the content of dissolved salts. A checker or tablet gently sank into the liquid, at which time the stopwatch was turned on. At the end of the passage of the checker in the pipe at the time it appeared in the transparent flask, the stopwatch was turned off and the time of passage of the pipe checker was recorded.

The studies were carried out in the following waters: tap water d = 1.00 g / cm ³ , formation d = 1.16 g / cm ³ and a solution of calcium chloride d = 1.35 g / cm ³ .

Studies have shown that with an increase in the density of the liquid in which the checker settles, its sedimentation rate increases linearly.

Checkers were prepared by pressing in a specially made form. For pressing the drafts, a hydraulic press was used, developing a pressure of up to 600 atm and a force of up to 10,000 kg. The working pressure during pressing was kept constant at 150 kg / cm ² .

Despite the high pressure during pressing, the density of the pieces did not exceed 1.9 g / cm ³ . Such data indicate that the pieces have a porous structure with a porosity coefficient of 12-14%. The presence of pore channels plays a positive role, because it increases the contact surface with water and the rate of dissolution of the checkers.

To increase the density of the checkers, a weighting agent, for example, soluble salts of barium, calcium, potassium and sodium, for example, nitrates and chlorides, was introduced into the proposed foam composition.

The content of the weighting agent in the checker is determined by the depth of the bottom of the well and the necessary speed of delivery of the checker to the bottom. The depth of the face varies from 1,500 to 4,500 m.

The rate of deposition of checkers depends on their size.

The dimensions of the checkers were selected experimentally: their diameters from 5 to 30 mm and a height of 5 to 200 mm.

Studies have shown that the optimal deposition rate is 0.6 m / s. Such a deposition rate is sufficient so that at a well depth of 2,000 m, a piece delivered to the bottom of the well, with dimensions of 20-30 mm in diameter and height of 50 mm, is deposited at a speed of 0.6 m / s in about 53-54 minutes.

As a result of research, it was found that the optimal dimensions of the checker: diameter - 20-30 mm and a height of 50 mm.

Increasing the height of the pieces up to 200 mm increases its dissolution time by 2-2.5 times.

Introduced into the proposed foam composition highly dispersed hydrophobic material plays the role of a disintegrant and reduces the dissolution time of the pieces by 1.5-2.0 times.

Regulation of the time of dissolution of the blocks and the effectiveness of their application is one of the most difficult tasks in the technology of processing the bottom-hole formation zone.

Too quickly dissolving the checkers leads to the loss of the active substance, and also leads to a decrease in the speed of their movement. A long dissolution time is also undesirable.

The effectiveness of their use depends on the size of the checkers and the method of their delivery to the place of their best use: in the interval of perforations in the well.

Studies have shown that with the combined mixture pressing of all components, gas evolution with the formation of foam begins at the bottom of the well. Therefore, it is better to deliver the components of the gas-generating mixture separately in the form of pressed pieces from individual components or a mixture of them.

To increase the dissolution time of the blocks when they move along the wellbore independently, i.e. without the use of special. devices for delivering checkers to the interval of perforations, apply the technique of dipping the prepared checkers in a 3% solution of a water-soluble polymer or in the melt of technical paraffin for collectors with a temperature above 50 ° C, followed by drying it.

For a more efficient use of gas-generating foam compositions and reliable delivery of checkers to the wellbore, it is better to use special devices for the simultaneous delivery of all components to the perforation interval and for supplying the device to the formation fluid stream. You can place the device in the wellbore in a suspended state or with support on the bottom, for example, as a special. the device described in one of the patents: (see RF patent No. 2227206 7 ЕВВ 37/06, publ. 2004.04.20, "A method for supplying a solid reagent to a well and a device for its implementation").

Specified spec. the device is described simply as an example, as one of the possible options for the delivery of checkers in the region of the interval of perforation.

Such or similar device for supplying solid reagents to the well contains a module of sections with placement of one type or different types in each section of solid reagent. The sections are interconnected at the ends and communicated with each other by holes in the perforated base.

When using such or similar specials. devices provides the possibility of stable uniform and economic removal of solid reagents with different modes of operation of the well and at any viscosity of the reservoir fluid.

It was found that with increasing temperature, the deposition rate under the turbulent regime increases slightly. So, with an increase in temperature from 20 ° C to 60 ° C, the viscosity of water decreases by about 2 times: from 1 MPa · s to 0.47 MPa · s, and with a settling speed of 0.6 m / s the difference is due to an increase in temperature is not more than 10%.

The proposed foam composition is used to treat the bottom-hole zone of the formation, namely, to clean the reservoir of accumulated sludge and salts, since the high-molecular substances and surfactants contained in the composition due to flocculation remove the sludge and salts of clogged reservoirs to the surface efficiently and at high speed, 7- 8 times more effective when using ordinary water.

In addition, the proposed composition can be used to develop new or old wells after overhaul by injecting foam into the well until it is completely cleaned of clay, sludge, water and achieve a stable flow rate of liquid or gas. Due to the displacement of fluid in the well with foam, the back pressure on the formation gradually decreases.

Due to clogging by the bubbles of strong foam of cracks and pores of the channels, as well as due to hydrophobization of the rock surface, the influx of formation water is reduced.

The proposed foam composition can also be used for killing wells, especially in fields with abnormally low reservoir pressure, which are at a late stage of development.

The treatment of such wells is usually accompanied by the absorption of large volumes of water or aqueous solutions of high density.

Experimental studies have found that foams have a clogging ability of the pore channels.

When the foam is injected during its circulation in the bottom-hole zone, foam bubbles adhere to the surface of the pore channels. As is known, the sticking phenomenon is associated with the destruction of hydration layers located between the bubbles and the rock surface.

Dissolved gases reduce the hydration of the rock, adsorbing on it, forming polymer films. The adsorption of gases will lower the energy barrier, the overcoming of which is necessary for the adhesion of the bubble. All this creates favorable conditions for pinching foam bubbles in a porous medium, and therefore, the absorption of the washing liquid is prevented.

Well silencing with gas-generating foam systems containing a water-soluble polymer and the other components listed above is most effective because they have elastic and viscoplastic properties. When using such foam compositions for killing wells, the most important condition is met: killing fluid does not penetrate into the formation, since the viscosity and density of the foam can be varied over a wide range.

The proposed composition is prepared in the form of two options: in the form of a foamy water composition and in dry form, while instead of water, a weighting agent is added, which are used metal salts.

The foamy aqueous composition is prepared by thorough mixing according to the formulation of the components in wt.%: Surfactant or surfactant mixture 0.1-3.0; water soluble polymer - 0.1-5.0; VDGM - 0.1-3.0; complexone - 0.5-3.0; ammonium chloride - 4.79-35.4; alkali metal or alkaline earth metal nitrite - 6.20-45.7; alkali metal hydroxide - 0.5-10.0; dry organic acid - 3.75-20.0; the rest is water.

The proposed composition may contain a crosslinker - a salt of a polyvalent metal in an amount of 0.01-0.20 wt.%, As well as dry organic acid monochloracetic acid MHUK and additionally sodium salt MHUK in the range of ratios MHUK: Na-salt MHUK as 4: 1-2 :one.

According to the second option, the composition is prepared in the form of checkers. To do this, separate components or a mixture of them are loaded into the mold and the dry mass is pressed in the form of checkers of the required size.

To determine the increase in the permeability of the reservoirs and increase their oil-displacing ability, filtration studies were carried out by injecting the proposed composition in the form of foamy water compositions, as well as processing of producing and injection wells of the fields using a dry acid version of the composition in the form of checkers.

Example 1. For the preparation of the claimed composition in the form of a foamy aqueous solution containing the calculated amount of components in wt.%, It is necessary: surfactant or surfactant mixture 0.1-3.0; water soluble polymer - 0.1-5.0; VDGM - 0.1-3.0; complexone - 0.5-3.0; ammonium chloride - 4.79-35.4; alkali metal or alkaline earth metal nitrite - 6.20-45.7; alkali metal hydroxide - 0.5-10.0; dry organic acid - 3.75-20.0; the rest is water.

Compositions 21-25 of the proposed composition contain MHUK and sodium salt MHUK in the range of ratios 5: 1-1: 1, and compositions 1.7, 11, 15, 19, 20, 22 and 24 a crosslinker is a salt of a polyvalent metal in an amount of 0.005 - 0 25 wt.% (See table 3).

The prototype composition contains in wt.%: Surfactant 0.04-0.50; water soluble polymer 0.05-0.8; gas generators - ammonium chloride - 4.79-35.4; alkali or alkaline earth metal nitrite 6.20-45.7; the initiator of the reaction of aluminum chloride is 5.0-22.5 and water.

To filter the proposed composition, 220 mm long stainless steel columns with an inner diameter of 32 mm, equipped with shirts for thermostating, are filled in advance, which are filled with a mixture containing sandstones that are unevenly divided by interlayers of dense differences of silts and clays from the Bobrikovsky horizon field of the Visean tier of the Samara region. The models are saturated with water under vacuum, thermostated at 90 ° C, and the initial fresh water core permeability is determined by gravity, which is 1.12-2.75 μm ² (K ₁ ). Then the claimed composition is filtered on a filtration plant in order to determine the increase in permeability.

Through the column is pumped one pore volume of the claimed composition, then three pore volumes of the core of water. After that, determine the permeability to water (K ₂ ). The increase in permeability in% is determined by the change in core permeability in water before and after pumping the composition: K ₁ / K ₂ · 100%.

The filtering results of the proposed compositions of the composition and composition of the prototype (the content of the components shown in tables. 2 and 3) are presented in table 5.

The filtration results show that after filtering the claimed composition in the form of foamy water compositions, the increase in permeability is 1.05-3.68 times, and after filtering the prototype composition it is 1.04-1.68 times (see table 5) .

Example 2. For the preparation of the inventive composition in the form of a foamy aqueous solution containing the estimated amount of components in wt.%, It is necessary: surfactants or mixtures of surfactants 0.1-3.0; water soluble polymer - 0.1-5.0; VDGM - 0.1-3.0; complexone - 0.5-3.0; ammonium chloride - 4.79-35.4; alkali metal or alkaline earth metal nitrite - 6.20-45.7; alkali metal hydroxide - 0.5-10.0; dry organic acid - 3.75-20.0; the rest is water.

Compositions 21-25 of the proposed composition contain MHUK and sodium salt MHUK in the range of ratios 5: 1-1: 1, and compositions 1,7, 11, 15, 19, 20, 22 and 24 a crosslinker - a salt of a polyvalent metal in an amount of 0.005-0 25 wt.% (See table 3).

The prototype composition contains in wt.%: Surfactant 0.04-0.50; water soluble polymer 0.05-0.8; gas generators - ammonium chloride - 4.79-35.4; alkali or alkaline earth metal nitrite 6.20-45.7; the initiator of the reaction of aluminum chloride is 5.0-22.5 and water.

The oil-displacing ability of the proposed compositions is determined under the conditions of additional washing out of residual oil on a linear model of a homogeneous reservoir, which is the above-described stainless steel core. The core is filled with the above mixture. The model is saturated with water under vacuum, thermostatted at 90 ° C, and the core permeability to water is determined by the weight method.

After that, oil is injected into the core under pressure until clean (without water) oil appears at the outlet, then the initial oil saturation of the core is determined. In the filtration works, natural oil is used with a density of 842 kg / m ³ and a dynamic viscosity of 8.5 MPa · s at 20 ° C. The initial displacement is carried out with water (three pore volumes) and the coefficient of oil displacement by water is determined. Then, one pore volume of the test composition is filtered through a core, then three pore volumes of water are determined, the growth and the total oil displacement coefficient are determined.

The filtering results of the claimed compounds and prototype compositions for determining their oil-displacing ability are presented in table.6.

Example 3. A gas-generating foam system is used to develop and launch a muffled production well.

The production well of the field is self-silenced. Before the well was withdrawn from inactivity, the water cut was 96%. The amount of produced fluid before treatment was 70 m ³ / day, and the oil flow rate was zero. The depth of the bed is 2000 m. The reservoir pressure is 213 atm. The tubing is lowered to the upper perforation holes. The inner diameter of the string is 130 mm, the inner diameter of the tubing is 63 mm, the outer diameter of the tubing is 73 mm. The average density of the borehole fluid is 1136 kg / m ³ .

To prepare the inventive composition in the form of checkers containing the number of components, we took in wt.%: Neftenol K - 1,0; PAA grade AK-642 - 2.0; titanium oxide - 1.0; complexone EDATUK - 0.5; ammonium chloride - 21.4; barium nitrite - 46.0; sodium hydroxide - 0.1; MHUK - 4.0; sodium salt of MHUK - 1,0; the rest of the weighting agent is potassium nitrate.

For well development with foam checkers, it is required to create a depression of at least 20 atm. It is necessary to calculate the mass of gas-generating foam blocks.

Based on the geometry of the downhole tubes, the volume of fluid in 1 m of tubing is approximately 3 l, and in 1 m of annulus 9.1 l. Before treatment, the reservoir pressure of 213 atm is equal to the bottomhole pressure. Therefore, at a well fluid density of 1136 kg / m ³ , the fluid level in the tubing and annulus is located at zero.

As a result of the chemical reaction of ammonium chloride and sodium nitrite, nitrogen is generated in the foam composition. Under normal conditions, 1 mol of gaseous nitrogen occupies a volume of 22.4 liters, then, in terms of 1 g of stoichiometric mixture, V = 22.4 / 53.5 + 69.0 = 0.1829 l / g, where NH ₄ Cl 14+ 435.5 = 53.5 g / mol and NaNO ₂ 23 + 14 + 2 × 16 = 69 g / mol.

The yield of nitrogen under normal conditions per 1 kg of stoichiometric mixture is 182.9 liters.

After the checkers are delivered to the face, a chemical reaction begins with the release of nitrogen, which is accompanied by an increase in pressure. With a multiplicity of foam equal to 3, the minimum density of the foam at the wellhead with a water density of 1136 kg / m ³ is 1136 × 0.33 = 375.54 kg / m ³ .

After the overflow of foam, a drop in the liquid level in the annulus and a decrease in bottomhole pressure begin. The volume of the transfused liquid was 1.1 m ³ , the volume of one meter of the annulus is 9.1 m, then the liquid level in the annulus will decrease by 1100: 9.1 = 120.8 m. With a liquid density of 1136 kg / m ^{3, the} bottomhole pressure will decrease by 120.8 / 10 × 1.136 = 13.7 atm, which corresponds to a volume of 220 × 9.1 = 2002.0 liters.

With a multiplicity of foam equal to 3, 1 liter of liquid in the foam accounts for 2 liters of gas. Therefore, to displace 2002.0 l of liquid, it is necessary under normal conditions 2002.0 × 2 = 4004.0 l of gas. Since the generating ability of the claimed composition is 182, 9 liters per 1 kg of drafts, 21.8 kg of foam drafts will be required to generate 4004.0 l of gas.

In order to take into account some technological aspects, for example, in addition to the drop in the liquid level in the annulus, when the foam is generated, fluid will come from the reservoir. And the calculation of the volume of this fluid is quite complicated. Therefore, for the technology of well development with foam compositions, pilot tests are necessary.

After injection of the composition, the well is allowed to react for 3-5 hours.

After the well was put into the operating fund, the amount of produced fluid remained the same - 70 m ³ / day, while the oil production rate was 5.5 tons / day, the water cut was reduced to 90%.

Example 4. The inventive composition in the form of drafts is used in the field in a production well to clean the reservoir of sludge and salts. The processed interval of the bottomhole formation zone is 4 m.

Before the collector was cleaned, the amount of produced fluid was 25.8 m ³ / day, oil flow rate - 2.7 tons / day, and water cut - 93%.

To clean the terrigenous collector, a composition composition is prepared containing in wt.%: ML-super - 2.0; PAA edema. - 2.0; perlite - 1.5; complexon NTUK - 1.0; ammonium chloride - 26.80; potassium nitrite - 42.5; potassium hydroxide - 0.9; THUK - 5.2; weighting agent - barium nitrate rest.

Based on the studies, it was found that 1 to 1 perforated power requires from 6 to 18 rods of dry acid composition.

The prepared rods are thrown inside the tubing through a gland lubricator installed on the wellhead at the rate of 14 rods per 1 m of the treated interval, namely, 14 × 4 = 56 rods.

The well is shut off for 3-5 hours, then the pressure is gradually vented through the tubing or annulus, a call is made for the flow of fluid from the reservoir, and the well is put into operation.

As a result of the reservoir cleaning, the amount of produced fluid increased from 25.8 to 50 m ³ / day, and the oil production rate increased from 2.7 t / day to 5.4 t / day. The productivity of the reservoir has increased as a result of the application of the proposed dry acid composition due to the purification of the contaminated reservoir of PZP 2 times.

Example 5. The inventive variant of the foam dry-acid composition is used in commercial conditions in the injection well. The injectivity of the well before treatment was 22 m ³ / day at a pressure of 9.0 MPa, the perforation interval is 5 m

To clean the well, a composition was prepared containing in wt.%: Surfactant grade OP-10 - 0.5; KMTS-600 - 3.0; talc - 3.0; complexone DN EDAPUCK - 2.0; ammonium chloride - 30.2; calcium nitrite - 37.2; sodium hydroxide - 0.1; MHUK - 9.0; sodium salt of MHUK - 3.0; weighting agent - barium nitrate rest.

Prepared rods are thrown into the processed PZP interval at the rate of 12 rods per 1 m of the processed interval, namely 12 × 5 = 60 rods.

The well is stopped for aging for 3-5 hours, then after aging put into operation.

The injectivity of the well increased from 27 m ³ / day to 83 m ³ / day.

As a result of the application of the proposed foamy dry acid composition in the form of checkers, the injectivity of the well increased by 3 times due to the purification of the contaminated reservoir of the bottomhole formation.

The technical result is to increase the efficiency of acid treatment of reservoirs by improving the rheological properties of the composition, reducing the reaction rate of the acid composition with the rock and its corrosive activity, increasing the efficiency of cleaning collectors from clogging solid particles by floculating them, reducing the rate of deposition of sparingly soluble salts and increasing the solubility of salt deposits on the treated surfaces of the collectors, increasing the washing properties of the composition and hydrophobization of terrigenous call vectors to prevent the formation of silica gels in the near-wall space of the collector, which are the product of the reaction of acid with cement stone, as well as the increase in oil-displacing properties of the composition.

The use of an effective foam composition maximally preserves the reservoir properties of the formation, increases the productivity of the wells, and increases the overhaul period of the well.

Table 3. The content of additional components in the compositions of the claimed composition. No. p / p Structure Sodium salt MHUK Polyvalent Metal Salt The range of ratios MHUK: sodium salt MHUK Qty mark in one 2 3 four 5 6 one The claimed AlCl ₃ 0.005 3 The claimed - - 5 The claimed - - 7 The claimed Chrome Potassium Alum 0.01 9 The claimed - - eleven The claimed AlNO ₃ 0.02 13 The claimed - - fifteen The claimed Potassium dichromate 0.04 17 The claimed - - 19 The claimed Aluminum acetate 0.10 twenty The claimed Chromium acetate 0.15 21 The claimed 5: 1 0.8 - - 22 The claimed 4: 1 1,0 Chrome Potassium Alum 0.20 23 The claimed 3: 1 3.0 - - 24 The claimed 2: 1 2.0 Chrome Alum Waste 0.25 25 The claimed 1: 1 4.0 - - 26 The claimed - - 27 The claimed - -

Table 4.
The properties of the compositions of the inventive foam composition and the composition of the prototype. No. Structure Properties of the foam composition Foam ratio The density of the foam, g / cm ³ Stability of the foam at a temperature, ° C, after 50 minutes Lifetime, min, days 40 60 80 one 2 3 four 5 6 7 8 one The claimed 0.25 - - - - - 2 Prototype 0.20 - - - - - 3 The claimed 6.0 0.18 stable stable unstable 15 minutes. four Prototype 6.0 0.20 stable unstable unstable 10 min 5 The claimed 5,0 0.22 stable stable unstable 45 min 6 Prototype 5,0 0.22 stable stable unstable 25 min 7 The claimed 4,5 0.25 stable stable stable More than 15 days. 8 Prototype 4,5 0.26 stable stable stable Less than 2 hours. 9 The claimed 4.0 0.24 stable stable stable 60 min 10 Prototype 4.0 0.24 stable stable unstable 30 minutes. eleven The claimed 3,5 0.26 stable stable stable More than 15 days. 12 Prototype 4.0 0.24 stable stable unstable 40 min 13 The claimed 3,5 0.26 stable stable stable 90 min fourteen Prototype 4.0 0.25 stable stable unstable 40 min fifteen The claimed 3.0 0.35 stable stable stable More than 15 days. 16 Prototype 4.0 0.25 stable stable unstable 45 min 17 The claimed 3.0 0.30 stable stable stable 110 min eighteen Prototype 4.0 0.25 stable stable unstable 45 min 19 The claimed 4.0 0.24 stable stable stable More than 15 days. twenty The claimed 3.6 0.29 stable stable stable More than 15 days. 21 The claimed 5,0 0.23 stable stable stable 70 min 22 The claimed 4.0 0.25 stable stable stable More than 15 days. 23 The claimed 5,0 0.24 stable stable stable 80 min 24 The claimed 3.8 0.28 stable stable stable More than 15 days. 25 The claimed 4,5 0.25 stable stable unstable 45 minutes 26 The claimed 3.4 0.26 stable stable stable 90 min 27 The claimed 3.6 0.28 stable stable stable 110 min

Table 5.
The filtration results of the compositions of the proposed foam composition and the composition of the prototype. No. Structure Permeability, μm ² Permeability increase
K ₁ / K ₂ Before filtering, K ₁ After filtration, K ₂ one 2 3 four 5 one The claimed 1.16 1.22 105 2 Prototype 1.12 1.15 103 3 The claimed 1.42 1,56 110 four Prototype 1.30 1.38 106 5 The claimed 1.75 3.20 183 6 Prototype 1.82 3.00 165 7 The claimed 1.83 5.45 298 8 Prototype 1.80 2.93 163 9 The claimed 2.10 5.50 262 10 Prototype 2.06 3.31 161 eleven The claimed 2.23 7.20 323 12 Prototype 2.16 3.63 168 13 The claimed 2,32 6.49 280 fourteen Prototype 2.26 3.68 163 fifteen The claimed 2,58 9.49 368 16 Prototype 2,52 4.03 160 17 The claimed 2.75 7.28 265 eighteen Prototype 2.63 4.42 168 19 The claimed 2,55 7.39 290 twenty The claimed 2.48 7.93 320 21 The claimed 1.92 4.82 251 22 The claimed 2.02 6.76 335 23 The claimed 1.86 4.79 258 24 The claimed 2.61 8.09 310 25 The claimed 2,37 5.87 248 26 The claimed 2.42 5.61 232 27 The claimed 2.65 6.67 252

Table 6.
Oil-displacing properties of the compositions of the proposed composition and the composition of the prototype. No. Structure Initial oil saturation,% Oil displacement rate on water growth common one 2 3 four 5 6 one The claimed 65.5 0.64 0.16 0.80 2 Prototype 65.0 0.63 0.12 0.76 3 The claimed 68.0 0.63 0.19 0.82 four Prototype 70.3 0.62 0.14 0.76 5 The claimed 69.5 0.63 0.25 0.88 6 Prototype 71.7 0.62 0.16 0.78 7 The claimed 70.6 0.63 0.27 0.90 8 Prototype 72.0 0.62 0.15 0.78 9 The claimed 72.5 0.62 0.25 0.87 10 Prototype 71.2 0.62 0.14 0.76 eleven The claimed 71.9 0.63 0.27 0.90 12 Prototype 69.1 0.62 0.14 0.76 13 The claimed 68.6 0.63 0.29 0.92 fourteen Prototype 66.0 0.62 0.15 0.77 fifteen The claimed 68.5 0.63 0.26 0.89 16 Prototype 72.3 0.62 0.14 0.76 17 The claimed 67.5 0.63 0.27 0.90 eighteen Prototype 69.3 0.62 0.13 0.75 19 The claimed 66.3 0.63 0.30 0.93 twenty The claimed 70.8 0.62 0.15 0.77 21 The claimed 71.5 0.64 0.30 0.94 22 The claimed 66.8 0.64 0.28 0.92 23 The claimed 71.8 0.63 0.30 0.93 24 The claimed 72.0 0.63 0.31 0.96 25 The claimed 69.6 0.64 0.26 0.90 26 The claimed 70.5 0.63 0.27 0.90 27 The claimed 71.6 0.63 0.28 0.91

Claims (6)

1. A gas-generating foam composition for treating a bottom-hole formation zone containing a surfactant or surfactant mixture, a water-soluble polymer, a reaction initiator, ammonium chloride, an alkali or alkaline earth metal nitrite and water, characterized in that it contains dry organic acid as an initiator of the reaction and additionally highly dispersed hydrophobic material, complexon and alkali metal hydroxide in the following ratio of components, wt.%:
Surfactant or surfactant mixture 0.1-3.0 Water soluble polymer 0.1-5.0 Dry organic acid 3.75-20.0 Alkaline or alkaline earth metal nitrite 6.20-45.7 Ammonium chloride 4.79-35.4 Fine hydrophobic material 0.1-3.0 Complexon 0.5-3.0 Alkali metal hydroxide 0.5-10.0 Water rest 2. The composition according to claim 1, characterized in that it further comprises a crosslinker - a salt of a polyvalent metal in an amount of 0.01-0.2 wt.%. 3. The composition according to claim 1, characterized in that it contains dry organic acid - monochloracetic acid MHUK and additionally - sodium salt MHUK in the range of ratios MHUK: sodium salt MHUK as 4: 1-2: 1. 4. Gas-generating dry acid foam composition for treating the bottom-hole formation zone containing a surfactant or surfactant mixture, a water-soluble polymer, a reaction initiator, ammonium chloride, an alkali or alkaline earth metal nitrite, characterized in that it contains dry organic acid, additional weighting agent, highly dispersed hydrophobic material, complexon and alkali metal hydroxide in the following ratio of components, wt.%:
Surfactant or surfactant mixture 0.1-3.0 Water soluble polymer 0.1-5.0 Dry organic acid 3.75-20.0 Alkaline or alkaline earth metal nitrite 6.20-45.7 Ammonium chloride 4.79-35.4 Fine hydrophobic material 0.1-3.0 Complexon 0.5-3.0 Alkali metal hydroxide 0.5-10.0 Weighting compound rest 5. The composition according to claim 4, characterized in that it further comprises a crosslinker - a salt of a polyvalent metal in an amount of 0.01-0.2 wt.%. 6. The composition according to claim 4, characterized in that it contains dry organic acid - monochloracetic acid MHUK and additionally sodium salt MHUK in the range of ratios MHUK: sodium salt as 4: 1-2: 1.