Gelling composition, dry mixture and methods of its preparation

FIELD: oil and gas industry.

SUBSTANCE: dry mixture comprises a copolymer of acrylamide and acrylic acid - 71.4-83.3 wt %, paraformaldehyde - 10.0-17.8 wt % and resorcinol - 6.3-11.4 wt % or copolymer of acrylamide and acrylic acid - 69.5-82.5 wt %, paraformaldehyde - 9.5-17.7 wt %, resorcinol - 6.1-10.6 wt %, and aerosil - 0.9-3.0 wt %. The gelling composition is prepared by dissolving any of the said compounds in water. At that the gelling composition without aerosil can also be obtained by the introduction of paraformaldehyde in water immediately after the copolymer of acrylamide and acrylic acid, and resorcinol - after complete dissolution of the copolymer of acrylamide and acrylic acid. The resulting gelling composition comprises a copolymer of acrylamide and acrylic acid - 0.17-0.80 wt %, paraformaldehyde - 0.03-0.20 wt %, resorcinol - 0.02-0.12 wt %, water - the rest, or a copolymer of acrylamide and acrylic acid - 0.17-0.80 wt %, paraformaldehyde - 0.03-0.20 wt %, resorcinol - 0.02-0.12 wt %, aerosil - 0.01-0.03 wt %, water - the rest.

EFFECT: increasing the efficiency and manufacturability of the gelling composition by ensuring the solubility in water used for its preparation of the dry mixture, simplifying of preparation of the composition at high mechanical and thermal resistance.

3 cl, 3 tbl, 5 dwg, 8 ex

 

The invention relates to the oil and gas industry, in particular to compositions for the alignment of the profile in injection wells and water control in producing wells, and can also be used to eliminate areas of acquisitions in the repair of production and injection wells and to improve the processability of the composition due to the ease of cooking, with high mechanical and thermal stability.

Known composition to isolate water production in high temperature formations containing polyacrylamide, salts of weak organic acids, and as a stapler - chromium acetate or methenamine with hydroquinone [1]. The disadvantage of this composition is the insufficient strength of the resulting gel.

The closest solution, taken as a prototype of the composition is a gel-forming composition containing a crosslinking agent, which is in capsules made of the first polymer, second polymer, capable of forming a gel in the presence of said crosslinking agent and the liquid [2]. Usually specified crosslinking agent selected from the group consisting of derivatives of polyvalent metals and organic cross-linking agents. In particular, as derived polyvalent metal may be used chromium acetate, and the organic stapler - resorti�. As the second polymer is particularly preferred substances are partially hydrolyzed polyacrylamides. This composition is complex and not sufficiently technologically, as crosslinking agent into the capsule from the specified first polymer, for example, by double emulsion technology, or spray drying.

The closest solution, taken as a prototype, is a method for preparing a gelling composition containing crosslinking agent, which is in capsules made of the first polymer, second polymer, capable of forming a gel in the presence of said crosslinking agent, and the liquid [2]. Usually specified crosslinking agent selected from the group consisting of derivatives of polyvalent metals and organic cross-linking agents. In particular, as derived polyvalent metal may be used chromium acetate, and the organic stapler - resorcinol. As the second polymer is particularly preferred substances are partially hydrolyzed polyacrylamides. The method of preparing a gelling composition is complex and not sufficiently technologically, as crosslinking agent into the capsule from the specified first polymer, for example, by double emulsion technology, or spray drying.

The prototype of the claimed dry cm�C for the preparation of gel-forming composition is applied to isolate the flooding of oil reservoirs dry mixture, containing, wt.%: polyacrylamide 60-75; RITIN-10 5-15; chromium acetate 5-10; bentonite clay 10-15; glycerin 0.3 to 1.0. Download of the specified reagent is carried out in the form of a suspension in water of the obtained dry mixture with a concentration of 0.2-0.7 wt.%. [3]. This dry mixture is not effective enough, because poorly soluble in water, forming a suspension in it. Furthermore, the mixture can be Packed during prolonged storage.

Task of the claimed group of inventions is to improve the efficiency and adaptability of the gel-forming composition by providing a solubility in water used for preparing a dry mixture, simplifying the preparation of the composition, with high mechanical and thermal stability, as well as - if necessary - prevent caking specified dry mixture.

The problem is solved in that the proposed gel-forming composition comprising a copolymer of acrylamide and acrylic acid, water and resorcinol as the stapler, characterized in that it further comprises as a stapler paraformaldehyde in the following ratio of components, wt.%:

A copolymer of acrylamide and acrylic acid is 0.17 and 0.80

Paraformaldehyde - 0,03-0,20

Resorcinol - 0,02-0,12

Water - the rest

or

additionally contains as stapler paraformaldehyde and Aerosil in the following ratio of components, wt.%:

FOSS�emer acrylamide and acrylic acid - 0,17-0,80

Paraformaldehyde - 0,03-0,20

Resorcinol - 0,02-0,12

Aerosil - 0,01-0,03

Water - the rest.

The problem is solved also by the fact that the proposed dry mixture comprising a copolymer of acrylamide and acrylic acid and an additive of the stapler, characterized in that it contains as the staplers paraformaldehyde and resorcinol, mixed in a ratio, wt.%:

A copolymer of acrylamide and acrylic acid - 71,4-83,3

Paraformaldehyde - 10,0-17,8

Resorcinol - 6,3-11,4

or

contains as staplers paraformaldehyde and resorcinol, and Aerosil as an anti-caking agent, mixed in a ratio, wt.%:

A copolymer of acrylamide and acrylic acid - 69,5-82,5

Paraformaldehyde - 9,5-17,7

Resorcinol - 6,1-10,6

Aerosil - 0,9-3,0.

The problem is solved also by the fact that the proposed method of producing aqueous gel-forming composition based on a copolymer of acrylamide and acrylic acid and with the use of resorcinol as a stapler is characterized in that the paraformaldehyde as a stapler poured into water immediately after the copolymer of acrylamide and acrylic acid, and resorcinol - after complete dissolution of the copolymer of acrylamide and acrylic acid or pre-prepared dry mixture of a copolymer of acrylamide and acrylic acid, resorcinol and paraformaldehyde, mixed in a ratio, wt.%:

A copolymer of acrylamide and acrylic acid - 71,4-83,3

Paraformaldehyde - 10,-17,8

Resorcinol - 6,3-11,4

- dissolve in water to a ratio of the resulting gel-forming composition, wt.%:

A copolymer of acrylamide and acrylic acid is 0.17 and 0.80

Paraformaldehyde - 0,03-0,20

Resorcinol - 0,02-0,12

Water - the rest

or

pre-prepared dry mixture of a copolymer of acrylamide and acrylic acid, resorcinol and paraformaldehyde as the staplers and Aerosil as an anti-caking agent, mixed in a ratio, wt.%:

A copolymer of acrylamide and acrylic acid - 69,5-82,5

Paraformaldehyde - 9,5-17,7

Resorcinol - 6,1-10,6

Aerosil - 0,9-3,0

- dissolve in water to a ratio of the resulting gel-forming composition, wt.%:

A copolymer of acrylamide and acrylic acid is 0.17 and 0.80

Paraformaldehyde - 0,03-0,20

Resorcinol - 0,02-0,12

Aerosil - 0,01-0,03

Water - the rest.

Exploring Aerosil as an anti-caking agent dry mixture of a copolymer of acrylamide and acrylic acid with paraformaldehyde and resorcinol, the authors have established the ability of Aerosil in an aqueous solution of the specified dry mixture to the crosslinked copolymer of acrylamide and acrylic acid, similar to the ability of paraformaldehyde and resorcinol. Since both the inventive gelling of the composition and Aerosil, and with Aerosil - have equal technical advantages over composition-the prototype by providing a solubility in water used for the pre�AI dry mix - without Aerosil and Aerosil - and, consequently, simplify the preparation of the gel-forming composition, with high mechanical and thermal stability, each invention of the claimed group of inventions is characterized by the applicant, a specified set of attributes with the use of alternatives to "or".

Aerosil GOST 14922-77 - superfine, highly active, amorphous, fumed silicon dioxide (SiO2). Used to thicken, impart thixotropic properties of liquids and active filling rubbers and sealants. Widely used also to give a free flowing powdered products. Performs the function of a stabilizer that acts as antiegalitarian multicomponent additive systems.

Paraformaldehyde (paraformaldehyde) THAT 6-09-141-03-89 - product of the polymerization of formaldehyde. It is a white, loose powder with the smell of formaldehyde. Used as a disinfectant. used in resorcinol-formaldehyde, phenol-formaldehyde, urea-formaldehyde and other resins, as well as in the manufacture of chemicals for oil drilling, additives for petroleum oils, adhesive resins and molded materials electrical components.

Resorcinol GOST 9970-74 - meta-dioxobenzo, white or yellowish white crystalline powder with a faint characteristic odor. Used in domesti�the production of drugs for the treatment of skin diseases, in the manufacture of explosives, resorcin-aldehyde resins, azo dyes, stabilizers and plasticizers of high molecular compounds.

A copolymer of acrylamide and acrylic acid, for example, partially hydrolyzed polyacrylamide brands A, SD-6800, AN-132, FP-107, etc., with a molecular weight of 6-18 million and a degree of hydrolysis of 5-30%. Used for purification of natural and industrial wastewater, the intensification of the processes of clarification, thickening and filtration technology brines, slurries, flotation concentrate and flototto, processes for enhanced oil recovery and drilling.

A dry mixture is prepared by mixing the components in a predetermined ratio in a dry form. Can use different types of mixers, mixing time from 5 to 20 minutes depending on the design of the mixer. The finished product is a dry powdery mixture.

Gel-forming composition without Aerosil, unlike the gel-forming composition of the aerosol, can be prepared not only by dissolving in water a dry mixture, but also by the indicated sequence of operations: paraformaldehyde poured into water immediately after the copolymer of acrylamide and acrylic acid, and resorcinol - after complete dissolution of the copolymer of acrylamide and acrylic acid. And in fact, and in another case, the methods for preparing gel-forming composition process easier and�her, than the prototype.

EXAMPLES

Example 1. On the water salinity of 235 g/l solution was prepared containing 0.5% of polyacrylamide brand SD-6800, 0.06% of paraformaldehyde, 0.04% of resorcinol. While paraformaldehyde is introduced into the solution immediately after polyacrylamide, and resorcinol - after complete dissolution of polyacrylamide. After gelation investigated thermal stability of the obtained sample. The contribution of oxidative degradation in the change of the viscous properties of a cross-linked polymer system (ATP) was determined after 8-hour incubation at 80°C and conducted research of rheological properties of ATP before and after destruction. The effective viscosity of the crosslinked polymer system were determined in the rheometer Haake Viscotester 550 at a shear rate of 0.01 to 300-1. The composition proved to be more resistant to thermal degradation as compared with the composition containing as a stapler chromium acetate: 0.5% polyacrylamide brand SD-6800, 0.05% chromium acetate, water - the rest (Fig. 1, tab. 1).

Fig. 1 the solid lines show the dependence of effective viscosity on shear rate for the ATP, and the dotted for gels after thermal degradation. At the same viscosities before degradation after degradation of the gel with organic stapler has a higher viscosity than the gel, crosslinked by chromium acetate.

Example 2. On the water salinity of 15 g/l �Otavio solution containing 0.5% of polyacrylamide brand SD-6800, 0.06% of paraformaldehyde, 0.04% of resorcinol. While paraformaldehyde is introduced into the solution immediately after polyacrylamide, and resorcinol - after complete dissolution of polyacrylamide. After gelation was investigated the stability of the sample to mechanical loads. The influence of the mechanical strength was evaluated after 20 minutes of stirring ATP to paddle stirrer with a speed of 500 Rev/min, the Composition was found to be more resistant to mechanical degradation compared with the composition containing as a stapler chromium acetate (Fig. 2, table. 2).

Fig. 2 the solid lines show the dependence of effective viscosity on shear rate for polymeric systems crosslinked by chromium acetate (upper line) and cross-linked by an organic linker (bottom line), and the dotted for gels after mechanical destruction. After the destruction of the gel with organic stapler has a significantly higher viscosity than the gel, crosslinked by chromium acetate.

Example 3. In fresh water (salinity less than 1 g/l) [4] solution is prepared containing 0.5% of polyacrylamide brand AN-132, 0,12% paraformaldehyde, 0.08% resorcinol. Paraformaldehyde is introduced into the solution immediately after polyacrylamide, and resorcinol - after complete dissolution of polyacrylamide. Determines the time of dissolution at room temperature and lying� of gelation at 30°C using the relaxometer design IPng RAS. Upon reaching values of relaxation time (life time of the thread) over 120 h polymer system is considered to have reached the required degree of crosslinking. This composition has a reasonable time of dissolution and gelation time (tab. 3).

Example 4. In fresh water solution is prepared containing 0.8% polyacrylamide brand AN-132, 0.20% paraformaldehyde, 0.12% of the resorcinol. Paraformaldehyde is introduced into the solution immediately after polyacrylamide, and resorcinol - after complete dissolution of polyacrylamide. Determines the time of dissolution at room temperature and the gel time at 30°C. it is Shown that a further increase in the content of the staplers is no advantage in time of crosslinking (table. 3).

Example 5. The components are mixed in dry form manually until a homogeneous mass in the following ratio, wt.%: polyacrylamide brand A 71,4, paraformaldehyde 17,2, resorcinol or 11.4. To obtain a solution containing 0.5% polymer, 0,12% paraformaldehyde and 0.08% of resorcinol, 0.7 g of the obtained dry mixture is dissolved in 100 ml of fresh water. Determines the time of dissolution at room temperature and the gel time at 30°C. Also, the effective viscosity is measured before and after gelation (Fig. 3).

Fig. 3 the dotted lines show the dependence of effective viscosity on shear rate for unsewn original solutions, and the solid - DL� ATP at different method of administration component: sequential dissolution and the dissolution of pre-prepared dry mixture. It is shown that the time of dissolution, gelation time and the effective viscosity does not depend on the method of introduction of the components into the solution.

Example 6. The components are mixed in dry form manually until a homogeneous mass in the following ratio, wt.%: polyacrylamide brand A 71,4, paraformaldehyde 17,8, resorcinol is 10.8. To obtain a solution containing 0.8% of resin, 0.20% paraformaldehyde and 0.12% of resorcinol, 1.12 g of the resulting mixture is dissolved in 100 ml of fresh water. Determines the time of dissolution at room temperature and the gel time at 30°C. Also, the effective viscosity is measured before and after gelation (Fig. 4).

Fig. 4 the dotted lines show the dependence of effective viscosity on shear rate for unsewn original solutions - lower of 0.5% PAA, the top 0.8% of PAA, and the solid - to ATP - bottom 0.5% of PAA, the top 0.8% of PAA.

It is shown that the increase in the content of PAA in the solution to 0.8% leads to an increase of effective viscosity. The decrease in the concentration below 0,17% is unreasonable, since a lower concentration of PAA gives unstable on the technological properties of the system [5].

Example 7. The components are mixed in dry form manually until a homogeneous mass in the following ratio, wt.%: polyacrylamide brand A 70,8, paraformaldehyde 17,7, resorcinol 10,6, Aerosil 0,9. To obtain a solution containing 0.8% of polymer�, 0.20% paraformaldehyde, 0.12% of the resorcinol and 0.01% Aerosil, 1.13 g of the resulting mixture is dissolved in 100 ml of fresh water. The effective viscosity, measured after gel formation at different shear rates, has an optimal value (Fig. 5).

Fig. 5 the upper curve corresponds to a shear rate 77,3 1/s, average - 108,4 1/s, the lower 213,7 1/S.

Example 8. The components are mixed in dry form manually until a homogeneous mass in the following ratio, wt.%: polyacrylamide brand A 69,6, paraformaldehyde 17,4, resorcinol 10,4, Aerosil 2,6. To obtain a solution containing 0.8% of resin, 0.20% paraformaldehyde, 0.12% of the resorcinol and 0.03% Aerosil, 1.15 g of the resulting mixture is dissolved in 100 ml of fresh water. Is determined by the effective viscosity after gelation at different shear rates (Fig. 5).

Fig. 5 the upper curve corresponds to a shear rate 77,3 1/s, average - 108,4 1/s, the lower 213,7 1/S. it is Shown that the concentration of Aerosil in the solution of 0.01-0.03% is optimal in this range of concentrations the viscosity maximum ATP. Further increase in the content of Aerosil not beneficial.

Thus, the inventive gelling composition is as essential as Aerosil, and Aerosil - effective and manufacturable prototype by providing a solubility in water used in its preparation dry mix, simplify the preparation of the composition, with high mechanical strength�coy and thermal stability; if necessary, is provided to prevent caking of the specified dry mixture.

SOURCES of INFORMATION

1. RF patent №2272891. METHOD OF ISOLATION OF WATER PRODUCTION IN HIGH-TEMPERATURE FORMATIONS. Publ. 27.03.2006.

2. RF patent №2250987. COMPOSITIONS AND METHODS INTENDED FOR USE IN THE OIL FIELDS. Publ. 27.04.2005.

3. RF patent №2352765. ISOLATION METHOD OF WATER FLOODING OF OIL RESERVOIRS. Publ. 20.04.2009.

4. "Water oil and gas fields of the USSR". Guide./Ed. by L. M. Zorkin. - M.: Nedra. - 1989 - 382 S.

5. Thelin A. G. and others regulation of the rheological and filtration properties of crosslinked polymer systems with the purpose of increase of efficiency of formation treatment // Bulletin of engineering center YUKOS. - 2002. - №4. - Pp. 41-45.

1. Gel-forming composition comprising a copolymer of acrylamide and acrylic acid, water and resorcinol as the stapler, characterized in that it further comprises a stapler paraformaldehyde in the following ratio of components, wt.%:
A copolymer of acrylamide and acrylic acid - 0,17-0,80
Paraformaldehyde - 0,03-0,20
Resorcinol - 0,02-0,12
Water - the rest
or
additionally contains as stapler paraformaldehyde and Aerosil in the following ratio of components, wt.%:
A copolymer of acrylamide and acrylic acid - 0,17-0,80
Paraformaldehyde - 0,03-0,20
Resorcinol - 0,02-0,12
The Aeros�l - 0,01-0,03
Water - the rest.

2. A dry mixture comprising a copolymer of acrylamide and acrylic acid and an additive of the stapler, characterized in that it contains as the staplers paraformaldehyde and resorcinol, mixed in a ratio, wt.%:
A copolymer of acrylamide and acrylic acid - 71,4-83,3
Paraformaldehyde - 10,0-17,8
Resorcinol is 6.3 to 11.4
or
contains as staplers paraformaldehyde and resorcinol, and Aerosil as an anti-caking agent, mixed in a ratio, wt.%:
A copolymer of acrylamide and acrylic acid - 69,5-82,5
Paraformaldehyde - 9,5-17,7
Resorcinol - 6,1-10,6
Aerosil - 0,9-3,0.

3. A method of producing aqueous gel-forming composition based on a copolymer of acrylamide and acrylic acid and with the use of resorcinol as a stapler, characterized in that the paraformaldehyde as a stapler poured into water immediately after the copolymer of acrylamide and acrylic acid, and resorcinol - after complete dissolution of the copolymer of acrylamide and acrylic acid or pre-prepared dry mixture of a copolymer of acrylamide and acrylic acid, resorcinol and paraformaldehyde, mixed in a ratio, wt.%:
A copolymer of acrylamide and acrylic acid - 71,4-83,3
Paraformaldehyde - 10,0-17,8
Resorcinol is 6.3 to 11.4
- dissolve in water to a ratio of the resulting gel-forming composition, wt.%:
A copolymer of acrylamide and acrylic acid - 0,17-0,80
Paraformaldehyde - 0,03-0,20
Water - the rest
or
pre-prepared dry mixture of a copolymer of acrylamide and acrylic acid, resorcinol and paraformaldehyde as the staplers and Aerosil as an anti-caking agent, mixed in a ratio, wt.%:
A copolymer of acrylamide and acrylic acid - 69,5-82,5
Paraformaldehyde - 9,5-17,7
Resorcinol - 6,1-10,6
Aerosil - 0,9-3,0
- dissolve in water to a ratio of the resulting gel-forming composition, wt.%:
A copolymer of acrylamide and acrylic acid - 0,17-0,80
Paraformaldehyde - 0,03-0,20
Resorcinol - 0,02-0,12
Aerosil - 0,01-0,03
Water - the rest.



 

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3 cl, 1 ex, 2 tbl

FIELD: oil and gas industry.

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

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

4 cl

FIELD: oil and gas industry.

SUBSTANCE: gas-cement grouting mortar contains, wt. pt.: grouting cement 100, aluminium powder 0.1-0.6, mix of a phosphanol and nitrilothrymetil phosphonic acid 0.02-0.05 at their ratio wt. pt. 1:1.5, water 50-53.

EFFECT: improvement of quality of cementation of wells and efficiency of works on cementing of loose weakly cemented rocks of bottomhole zone of formation during repair of wells due to use of gas-cement grouting mortar with improved process properties due to the lowered dynamic shear stress, increase of time of the beginning of gas emission and increased strength of cement stone formed at curing.

1 tbl, 4 ex

FIELD: oil and gas industry.

SUBSTANCE: invention relates to methods of current underground well workover. Method includes injection of silicon dioxide suspension that in itself does not have cementing properties, to cavities in the damaged cement enclosure or near it. At that silicon dioxide particles react with solidificated cement creating seals.

EFFECT: improved method.

8 cl, 12 dwg, 4 tbl

FIELD: mining.

SUBSTANCE: into the lower part of the impervious man-made screen containing dolerite rocks, the cement grouting is pumped, based on sulphate resistant or calcium aluminate cement with hardener (2% CaCl2) under pressure greater than hydrostatic, through the wells drilled from underground excavations. In the cement grouting the filler is used as mill tailings with a fraction of 0.1-0.25 mm, corresponding to fine sand. It is kept till hardening. After hardening the resulting rock-cement layer of the impervious screen is tamped with local injections of synthetic resins under pressure, less than the pressure of fracture of rock mass of mining protective pillar left under the screen. And the cement grouting is pumped under pressure of 0.7-0.8 MPa, and local injections of synthetic resin is carried out at a pressure of 0.5-0.6 MPa. The synthetic resin is used as hydro-active compositions based on LT-70 with the addition of a solvent - dimethylformamide in an amount of 20-25%.

EFFECT: increased strength and increased of impervious properties of the screen when filling the open pit.

6 cl, 2 dwg

FIELD: oil and gas industry.

SUBSTANCE: method of isolation of the water influxes to well comprises water isolation composition injection in the isolation zone, composition contains modified soluble glass, 3.6-10 or 1-3.5 parts by volume of ethyl acetate, and surface-active substance. At that in the water isolating composition 100 parts by volume of high-modulus soluble silicate with silica module 3.5-6 and density 1025-1200 kg/m3 is used as modified soluble silicate at temperatures exceeding 10°C. 0.2 parts by volume of detergent preparation with weight ratio of surface-active substances 30-38% and freezing temperature minus 30°C minimum are used as surface-active substance.

EFFECT: increased efficiency of water influx isolation and expansion of temperature range for the methods use.

2 cl, 2 ex, 2 tbl

FIELD: oil and gas industry.

SUBSTANCE: in method for elimination of behind-casing flows and inter-casing pressures, which involves preparation of aerated grouting mortars of light weight and normal density, their series delivery to a production string and squeezing to behind-casing and inter-casing spaces with squeezing liquid, as aerated grouting mortars of light weight and normal density there used are sedimentation stable fine-aerated solutions with densities of not higher than 1650 kg/m3 and not lower than 1800 kg/m3, which contain no extra Portland cement and heat-resistant plasticising and expanding additive including kaolin clay thermally activated at the temperature of 900÷1000°C with specific surface of 300÷400 m2/kg, aluminium sulphate, boric acid and an Aeroplast air-entraining additive excluding formation of stable foam, and mixing liquid at the following ratio of components, wt %: non-extra Portland cement 85-75, kaolin clay 10-18, aluminium sulphate 4.7-6.1, boric acid 0.2-0.5, Aeroplast air-entraining additive 0.1-0.4, mixing liquid over 100% till water-mixed ratios of 0.63÷0.65 m3/t and 0.40÷0.50 m3/t are obtained, with that, first, sedimentation stable aerated light-weight grouting mortar is delivered with controlled density of not more than 1650 kg/m3, then, aerated grouting mortar of normal density of not more than 1950 kg/m3 is delivered; with that, required densities of grouting mortars are provided by variation of a water-mixed ratio, intensity and duration of mixing, and squeezing is performed till partial displacement of aerated light-weight grouting mortar from behind-casing (inter-casing) space with squeezing liquid heated up to 50÷60°C during winter season and at cementing of low-temperature wells.

EFFECT: improving cementing quality.

2 tbl

Well treatment // 2549950

FIELD: textile, paper.

SUBSTANCE: method involves supply with a pump to a well shaft zone or to a bottom-hole zone of the well of a gel-forming material for protection against absorption of liquid mud (LCM) including a carrier liquid containing polymerising compounds. Material for protection against absorption also includes a polymerisation initiator and drops of an accelerator in covers, which is contained in them. Gel-forming material is subject to action sufficient for destruction of integrity of covers. Contact between polymerising compounds, the polymerisation initiator and the accelerator is provided.

EFFECT: improving absorption elimination efficiency.

20 cl, 3 dwg, 7 tbl, 5 ex

FIELD: oil and gas industry.

SUBSTANCE: invention is related to the technology intended for well productivity improvement. Large-volume selective acid treatment (LVSAT) for producers in carbonate reservoirs includes the injection to the well of an acid composite band with the specific volume of 1.5-3m3 per 1 m of an oil-saturated interval and non-linear viscous deflecting fluid before and/or upon the injection of the acid composite band, at that the injection of the acid composite is carried out with an optimal flow rate and an optimal ratio of a deflecting fluid volume to the acid composite volume, which are defined by mathematic modelling of the process considering changes in the wellhead and bottomhole pressure, type of the acid composite, type of the deflecting fluid, porosity and permeability of rock; at that for the purpose of the optimal flow rate optimisation for the acid composite injection dependencies of the optimal flow rate of injection on the specific volume of reagents injection are obtained with different constants of the reaction.

EFFECT: improved efficiency of large-volume selective acid treatment (LVSAT) for carbonate reservoirs.

2 cl, 5 tbl, 1 ex, 11 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to oil and gas extraction industry and can be used in modifying filtration properties of formations, during hydraulic fracturing, fluid flow separation in a well, borehole cleaning and other repair works. The multipurpose gel-forming composition includes 3-4 wt % carboxymethyl cellulose or polyanionic cellulose, 5-14 wt % potassium alum, 0.2-06 wt % sulphanole, 0.2-0.6 wt % propylene glycol, 0.02-0.06 sodium tetraborate and water.

EFFECT: obtaining a non-toxic, low-density gel-forming composition.

6 ex, 1 tbl

FIELD: oil and gas industry.

SUBSTANCE: in a preparation method of compositions for the isolation of behind-the-casing flows in a well that includes mixing of microcement and additives, oil well portland cement with the specific surface of 800 or 900 m2/kg is used as the microcement and a water-soluble acrylamide polymer, copolymer of vinyl amide and n-vinyl lactam, olefin sulphonate and polyethylene glycol at the water-cement ratio of 0.75-1.2 are used as the additives for the preparation of the composition; a microcement grouting fluid is prepared preliminarily with a solution of the above listed additives in water at simultaneous stirring, then the microcement is added to the produced fluid with the following ratio of ingredients, in weight parts: oil well portland cement with the specific surface of 800 or 900 m2/kg - 100, water-soluble acrylamide polymer - 0.01-0.02, copolymer of vinyl amide and n-vinyl lactam - 1.0-2.5, olefin sulphonate - 0.01-1.0, polyethylene glycol - 0.05-0.15, and water 75-120.

EFFECT: improved workability and efficiency in the isolation of behind-the-casing flows in the well due to the increased strength and expanded time range for hardening of the microcement-based composition.

1 tbl

FIELD: oil and gas industry.

SUBSTANCE: isolation method of water influx to well includes injection of organosilicone product to the isolated interval. At mixing to Devonian oil is added to organosilicone product; product 119-296I of B trademark is used as organosilicone product. The water is added with density of 1000-1190 kg/m3, the composite is mixed and injected to the isolated interval with the following ratio of ingredients, parts by volume: product 119-296I of B 100 trademark, water with density of 1000-1190 kg/m3 50-100, Devonian oil 10-20. The composite is reinforced by injection of liquid glass. At that buffer of fresh water is injected between the composite and liquid glass.

EFFECT: improved efficiency of water influx isolation due to regulation of time for gel formation of the injected composite and prevention of its early gel formation.

1 tbl

FIELD: oil and gas industry.

SUBSTANCE: group of inventions relates to inhibition of clay hydration during drilling and wells construction. Method of inhibition of clay hydration during drilling comprising use of water based mud containing from about 0.02 to about 5 wt % of bis-hexamethylenetetramine, salts of bis-hexamethylenetetramine or their mixtures as hydration inhibitor.

EFFECT: effective inhibition of clay hydration, stable inhibitor at ambient temperature, expansion of raw materials base due to wastes.

10 cl, 1 tbl, 1 dwg

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