Method of acid treatment of bottom-hole zone of carbonate reservoir

FIELD: oil and gas industry.

SUBSTANCE: method of acid treatment of bottom-hole zone of carbonate reservoir includes injection of the acid composition containing in wt %: inorganic or organic acid, or their mixture 9.0-24.0; zwitterion surface-active substance - oleinamidopropylbetaine 1.0-10.0; hydrophobically-modified polyurethane polymer 0.05-3.0; water - rest, at that the acid composition is injected by single stage or by portions with holding between injections. The acid composition can additionally contain anionic surface-active substance in amount of 0.1-3.0 wt %. The above specified acid composition is injected alternating with injection of hydrochloric acid at 12-24% concentration.

EFFECT: alignment of profile of inflow of the production wells in carbonate reservoirs with non-uniform permeability, creation of new fluid conducting channels through entire perforated thickness of the reservoir, restoration of reservoir characteristics of bottom-hole zone due to its cleaning of mud solid particles.

3 cl, 1 tbl, 16 ex, 4 dwg

 

The invention relates to the oil industry, in particular to methods of acid treatment of bottom-hole zone of carbonate reservoirs.

A method of processing bottom-hole zone of the well, including prodavcu in zone of the productive formation of an acid solution and surface-active substances (surfactants), technological exposure and the impact of depression (see RF Patent №2280154, MKI E21B 43/27, publ. 2006).

The known method is not effective enough due to incomplete coverage of the formation of acid exposure.

Known method of acidizing a subterranean formation comprising sequentially-alternating injection of water foamed viscoelastic deviating system and acid (see EPO Patent No. 009397, MKI E21B 43/27, publ. 2007).

This method involves the use of complex, unique equipment for injection of the composition into the reservoir and complicated in execution. In addition, the method involves the use of methanol, which is toxic, harmful to human health.

The closest in technical essence to the claimed method is a method of acidizing a subterranean reservoir, comprising the injection of a gelled acidic composition containing an inorganic or organic acid or mixtures thereof, a gelling agent zwitterion surfactant - amidoamines, Rast�oritel and water. RF patent №2311439, SC 8/24, publ. 2007).

Known composition forms a viscoelastic gel only in a narrow range of concentrations of hydrochloric acid (12-8 wt.%) and unable to maintain viscosity at high temperatures of the reservoir, so when the temperature increases from 24 to 65°C, the viscosity decreases from 1000 to 480 MPa·s. Also significant restrictions on the use of known composition is the high water cut oil reservoir.

Solved by the invention the task is to align the flow profile production wells in a heterogeneous permeability reservoirs, in the creation of new fluid-conducting channel across the thickness of the perforated layer, and also in the recovery reservoir properties of the bottomhole zone with special cleaning from clogging solids.

The problem is solved by creating a method of acid treatment of bottom-hole zone of the carbonate reservoir, including the injection of the acidic composition containing an inorganic or organic acid or mixtures thereof, zwitterion a surfactant and water, and as zwitterionic surfactant composition comprises alkylbetaine, and optionally, the hydrophobic-modified polyurethane resin in the following ratio of components, wt.%:

inorganic or organic acid or mixtures thereof9,0-24,0
alkylbetaine1,0-10,0
hydrophobic-modified
the polyurethane polymer0,05-3,0
waterthe rest,

moreover, the pumping of the acid composition is carried out in one stage or portions with the holding of the shutter between uploads.

In embodiments of the method the acid composition may further contain an anionic surfactant in an amount of 0.1-3.0 wt.%, and the method of injection of the acid composition may be interleaved with the injection of hydrochloric acid 12-24% concentration.

To prepare the acid composition is used, for example:

inhibited hydrochloric acid on THE 2458-264-05765670-99 am.1 (OJSC "Khimprom", Novocheboksarsk);

- hydrofluoric acid (HF) according to GOST 10484-78 (JSC Halogen, Perm);

- acetic acid (QM) standard 19814-74 (JSC "Nevinnomyssk Azot", the Stavropol territory);

- formic acid (MK) TU 9285-78;

- sulfamic acid (IC) in THE 2121-083-05800142-2001;

- Chloroacetic acid (HC) V. A. Rabinovich, Z. Ya havin Brief chemical Handbook. L.: Chemistry, 1977, str-192, 223.

Alienability (AAPB) is alkylbetaine with the following structure:

where: - R1represents alkyl, alkenyl, alkylresorcinol, acylaminoalkyl, alkenylamine, alkylamidoamines or alkanolammonium, where each of the alkyl groups contains from 16 to about 24 carbon atoms and may be branched or linear and saturated or unsaturated, and where said alkylene groups contain from 1 to 6 carbon atoms;

- R2, R3represent a hydrocarbon radical with a chain length from 1 to 4 carbon atoms.

Alkylbetaine produced in the: "Heather", Russia, Volzhsky; LLC "Plant of Santanarow, Russia, Nizhny Novgorod.

As anionic surfactants are used, for example:

- alkylsulfonate sodium (ASN) TU 2481-308-05763458-2001 (OJSC "Khimprom", Volgograd);

- alkyl aryl sulfonate sodium (ASN) according to GOST 12.1.007;

- alkylsulfate sodium (ASTN) TU 6-09-07-1816-93;

- alkylarylsulfonate sodium (AASTN) according to GOST 1253-56.

Hydrophobically modified polyurethane polymer (GMPO) is a hydrophobically modified ethylenoxide polymer of the following structure:

n=100-300

where R1- hydrocarbon radical with a chain length of 8 to 24 carbon atoms�;

R2group (C6H12).

GNU is a product of the company "Munzing Chemie GmbH, Germany, Heilbronn.

The introduction of the composition of hydrophobically modified polyurethane polymer increases thermal stability of the acid composition. The resulting neutralization of the acid composition of the viscoelastic gel is stable in contact with saline water, but is destroyed upon contact with hydrocarbons.

The basis of the claimed composition is the ability of the mixture of AB/GNU to form viscoelastic thermostable gel during the reaction of the acid with the carbonate rock, which creates an effective bias of the new portions of the acid composition from a high-permeability areas of the reservoir to previously untreated, low-permeability areas. Thus, the acid composition shows "samoudlinyayuschiesya properties. The mechanism of action acid composition based on the ability of the mixture of AB/GNU to form viscoelastic thermostable gel during the reaction of the acid with the carbonate rock in the interaction with the reaction products. Initially, the newly created acid composition has a low viscosity that makes it easy to upload her into the bed, then as consuming the acid reaction with the rock and formation of chlorides of calcium and magnesium viscosity obrazovash�gosia gel increases. After completion of the processing stage upon contact with hydrocarbons is the complete destruction of viscoelastic gel, i.e., a reverse fluid flow occurs cleaning of bottom-hole formation zone. Thus, the use of "samoudlinyayuschiesya" acid compositions provides uniform processing of the productive interval of the formation. The resulting acid composition is thermally stable and can be used in water-flooded reservoirs.

Claimed acid composition in the laboratory is prepared as follows. The compositions of the prepared compositions shown in the table.

Example 1 (inventive composition).

To 1.0 g of realmediasplitter (OAPB) add 0.05 g of the GMLC, 25,71 g of hydrochloric acid (an aqueous solution of 35 wt.%) and 73,24 g of water.

The resulting mixture was stirred for 40 minutes to obtain a homogeneous composition.

Examples 2-15.

The composition is prepared analogously to example 1, by varying the components and their contents.

Example 16 (prototype).

To 80,0 g of hydrochloric acid (an aqueous solution of 35 wt.%) add a gelling agent containing 3.0 g of , 3.0 g of propylene glycol and 15.0 g of water.

Table
By p. pThe content of components �remain, wt.%
acidZPAVGMLCwater
1HCL 9,01,00,0589,95
2MK 10,03,00,586,5
3HF 12,05,01,581,5
4The criminal code of 24.010,02,8563,15
5SK 20,05,00,574,5
6HCl 153,01,580,5
7HC 9,010,00,0580,95
8HCL+HF 24,01,0/td> 0,8574,15
9HCL is 15.08,00,586,5
10MC+MK 15,02,00,582,5
11SC+HC 24,05,00,8570,15
12HCL 12,0CPAV+ASN 5,00,582,5
13HF+MC 15,0CPAV+action ACTN 1,10,0583,85
14MK+HK 10,0CPAV+HASN 8,03,079,0
15HCL 24,0CPAV+EAST 4,00,8571,15
16 prototypeHCL 28,0Alkylamidoamines�laminated 3,0 Propylene glycol 3,066,0

The mechanism of action of the compositions is evaluated by changing the viscosity of the resulting acid gel when processing bottom-hole zone carbonate reservoirs (see Fig.1). In the experiment, we use the composition No. 6 of the table. As can be seen in the figure, initially, the composition has a low viscosity, when using hydrochloric acid with 15% concentration of the effective viscosity less than 10 MPa·s. during the reaction of hydrochloric acid with the carbonate rock, the concentration of hydrochloric acid is reduced, it forms calcium chloride, the viscosity of obrazovavshegosya gel increases. After the neutralization of the acid 2265 viscosity is MPa·s.

Figure 2 shows thermal stability of viscoelastic gel formed after the reaction of the claimed composition (composition No. 6 of the table) with the carbonate rock in comparison with the prototype. As can be seen from the figure, when the temperature increases the viscosity of the inventive compositions is reduced slightly. To determine the effectiveness of the claimed acid compositions are conducting research of their action in porous media - on natural cores West of Leninogorsk area of the Republic of Tatarstan. Through the model of the reservoir pump 24 of the pore volume (PO) model of reservoir water 3 UNDER the leadership of�my acid composition and re-19 and model of formation water. Dynamics filter the acid composition is presented in figure 3. At the steady state filter mode, the initial permeability of the core by formation water amounted of 0.036 μm2. During injection, the acid composition in number 3 and the pressure increased sharply, and the value of R/Ro reached to 16.5. This indicates the formation in the reservoir model of viscoelastic barrier which prevents the breakthrough of acid through the core. Subsequent injection model of the reservoir water was accompanied by a gradual pressure reduction and stabilization after pumping 7 to. Permeability models for reservoir water at this point amounted to 0.057 μm, it increased compared to the initial 1,58 times. The model used for investigating the efficiency of the known composition. Using the model of the pump 20 and model of formation water, 7.5 ON the known composition and re-7,8 based ON a model of the reservoir water. When pumping ON 1,3-known compositions are the value of R/Ro is increased to 1.52. Post-filtering leads to a sharp drop in pressure. Thus, the application of the compositions of the prior art does not provide the required deflection. The results are shown in figure 4.

To prove compliance of the proposed method the criterion of "industrial applicability" give a specific example of determination of efficiency in industrial�business conditions. To increase the initial injectivity of wells or new pore channels download acid composition alternated with the injection of hydrochloric acid of 12-14% concentration. The volume injected hydrochloric acid and the acid composition and number of treatments is determined by the geological parameters of the bottomhole zone, ongoing and planned performance of the wells.

Tests acid composition were carried out on a certain well NGDU ğelkhovneftğ. Were fix 12 m3acid composition and 3.6 m3oil. When pumping the first portions of the acid composition was observed residual pressure drop in pipes from 50 to 30-35 ATM. At the same time decreased the pressure in the annulus 46 to 15 to 20 ATM., which may indicate that the injected acid composition moves along the most drained the interlayers. When produce last portions of acid composition of the rim of the oil capacity of 3.6 m3there was an increase in pressure from 50 to 70 ATM., which may indicate receipt of the acid composition in low-permeability streaks, the penetration of which requires increasing the pressure of injection. When using the claimed "samoudlinyayuschiesya acid compositions for 1.5 years it was produced additionally 488 tons of oil.

Thus, the use of "samoudlinyayuschiesya" sour�a combined composition in the method of processing bottom-hole zone of carbonate reservoir allows processing of bottom-hole zone of heterogeneous formation, the resulting gel is completely destroyed upon contact with hydrocarbons and is easily eliminated with the bottom hole, leaving no damage to the breed.

1. Method of acid treatment of bottom-hole zone of the carbonate reservoir, including the injection of the acidic composition containing an inorganic or organic acid, or mixtures thereof, zwitterionic surfactant surfactant and water, and as zwitterionic surfactant composition comprises alienability, and optionally, the hydrophobic-modified polyurethane resin in the following ratio of components, wt.%:

inorganic or organic acid
or mixtures thereof9,0-24,0
alkylbetaine1,0-10,0
hydrophobically modified polyurethane
polymer0,05-3,0
waterthe rest,

moreover, the pumping of the acid composition is carried out in one stage or portions with the holding of the shutter between uploads.

2. A method according to claim 1, characterized in that the key�acidic composition further comprises an anionic surfactant in an amount of 0.1-3.0 wt.%.

3. A method according to claims. 1, 2, characterized in that the pumping of the acid composition alternated with the injection of hydrochloric acid 12-24% concentration.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: method for interval acidising of a horizontal well using a carbonate reservoir, which includes lowering a pipe string into a well; pumping acid compositions into the formation through the pipe string; conducting geophysical investigations in the horizontal well before treatment; selecting and separating intervals of the horizontal well into two groups; the first group includes intervals with permeability of 40-70 mD and water cut of the extracted product of 70-80%; the second group includes intervals with permeability of 5-39 mD and water cut of the extracted product of 50-69%; lowering into the horizontal well a pipe string plugged at the bottom and fitted with two packers with a perforated connecting pipe in between; performing consecutive treatment of the intervals of the horizontal well relating to the first group by sealed cut-off of each interval with subsequent alternating pumping into each interval in three cycles a temporary blocking composition at a rate of 6-12 m3/h, the temporary blocking composition used being a water-in-oil emulsion with dynamic viscosity of 120 mPa·s at 20°C, and an acid composition at a rate of 54-66 m3/h; after treatment of the intervals of the horizontal well relating to the first group, retrieving the pipe string from the horizontal well; at the mouth of the horizontal well, the pipe string is fitted with a liquid pulsator above the perforated connecting pipe and the pipe string which is plugged at the bottom and fitted with two packers with a perforated connecting pipe in between is once more lowered into the horizontal well; treating the intervals of the horizontal well of the second group by sealed cut-off of each interval with subsequent pulsed pumping into each interval a self-deviating acid composition based on a gelling agent at a rate of 24-36 m3/h.

EFFECT: intensifying oil extraction from a horizontal well, increasing oil yield and reducing the water cut of the extracted product.

3 dwg

FIELD: oil and gas industry.

SUBSTANCE: method of acid treatment of the oil reservoir includes geophysical survey in open horizontal wellbore to determine dislocations crossed by the bore in the reservoir, i.e. cracks, fractures, cavities, run in the horizontal wellbore on pipes string the filters with variable perforation density, packers installation, acid injection in horizontal wellbore, acid flush, well washing and commissioning. At that one packer is installed upstream the opened wellbore between the casing string and pipes string, and rest packers (expansing packers) are installed at places where the bore crosses dislocations. For each dislocation packer is selected with length exceeding width of the dislocation determined according to geophysical curves by at least 10 times. In pipes string hydrochloric acid with concentration 10-20% is injected on the basis 5-30 m3 per meter of oil-saturated reservoir thickness under wellhead pressure Pwh=(0.008…0.011)·H, MPa, where H is average depth of the reservoir, m. Perforation holes of filters are made round with diameter 5-10 mm, similar along the wellbore. Density of filters perforation for each section created between the packers, and between packer and bore end is increased linearly from zero at periphery to maximum in centre, in its turn this is determined via the hydrodynamical perfection coefficient as follows: k1h1Lnl1rc+С1=k2h2Lnl2rc+С2=...=knhnLnlnrc+Сn, where C1, C2, Cn are hydrodynamical perfection coefficients of the well as per character of opening on each nth section along the horizontal wellbore; l1, l2, ln are length of nth section, m; k1, k2, kn are average permeability of nth section, m2; h1, h2, hn are average oil saturated thickness of nth section, m; rc is well radius, m.

EFFECT: increased oil recovery of the reservoir due to increased reservoir coverage by action.

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FIELD: oil-and-gas industry.

SUBSTANCE: oil field development method involves working fluid pumping in through the injection wells and formation products withdrawal through the retrieving wells. The oil field is developed with the established ratio of formation products withdrawal compensation through working fluid pumping in. The borehole zone is treated with acid in the injection wells. The oil field is developed with the newly established ratio of formation products withdrawal compensation through working fluid pumping in until approach of the displacement front, changed as the result of acid treatment, to the retrieving well. Hydrofracturing is performed in the retrieving well with withdrawal compensation recovered to the initial value after recovery of formation products water content changed as a result of hydrofracturing.

EFFECT: field oil yield increase.

1 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: oil-and-gas industry.

SUBSTANCE: proposed process comprises lowering of flow string in hydrofrac zone and sealing of well annulus by packer. Rock is subjected to hydrofracturing to produce cracks by forcing gasified fluid via said flow string with the fracture propping. After sealing of casing string-borehole annuity packer is used to cool bottom hole zone by nitrogen gas with temperature of minus 40 to minus 45 degrees Centigrade. Then, hydrofrac is performed by injection of the mix of hydrochloric acid and nitrogen in amount sufficient for production of hydrochloric acid foam with foam content of 57% at well bottom. Then, 220°C superheated steam is forced via said flow string to hydrofracture. Note here that volume of said steam is selected to equal or to exceed that of forced hydrochloric acid foam and that of flow string. Now, the well is operated.

EFFECT: higher efficiency of fracturing.

1 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: composition for bottom hole formation zone processing comprises following elements in wt %: hydrochloric acid - 10.0-20.0, anionic surfactant, or non-ionic surfactant, or cationic surfactant, or mix thereof - 0.4-3.0, phosphorus compound AFON 300M - 0.01-15.0, solvent - 5.0-25.0, water making the rest. Proposed process comprises injection of said acid compound and its driving. Said compound is held to remove the reaction products. Note here that said acid compound is forced in pulse mode or in continuous mode in amount of 1-3 m3 per running meter of perforated depth of the bed at pressure allowable for this bed.

EFFECT: higher capacity of injection wells and fluid inflow due to decelerated reaction with bed rock, lower intensity of acid corrosion.

4 cl, 2 tbl, 17 ex

FIELD: oil and gas industry.

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EFFECT: improved sweep efficiency and increased oil recovery of the oil deposit.

1 dwg

FIELD: oil and gas industry.

SUBSTANCE: acid composition for acid treatment of production and injection wells in carbonate and terrigenous reservoirs contains the following, wt %: hydrochloric acid (24% or 36%) 25.0-50.0, alkyl benzene sulphonic acid containing in an alkyl group 12-14 atoms of carbon, 0.1-2.0, citric acid 0.5-3.0, acetic acid 3.0-12.0, methyl alcohol 3.0-10.0, OS-20 preparation 0.5-2.5, IKU-118 corrosion inhibitor 1.0-5.0, hydrofluoric acid (40%) 0.0-7.5, Feriks iron stabiliser 0.0-5.0, and water is the rest. An acid treatment method of the bottom-hole zone of a carbonate, terrigenous or mixed formation involves pumping to the well of the acid composition in the amount of 1.0-5.0 m3 per 1 m of perforated thickness of the formation, its forcing-through into the formation, exposure for the reaction during not more than 8 hours and further removal of reaction products; as an acid composition, there used is the above said composition or its solution in fresh water at the ratio of the above said composition to fresh water, which is equal to 1:1-1:2 respectively. The treatment method is developed in claims.

EFFECT: creation of a composition for acid treatment, which has low corrosion rate at formation temperatures; considerable improvement of efficiency of acid treatment.

3 cl, 3 tbl, 4 ex

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3 ex, 7 dwg

FIELD: oil and gas industry.

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EFFECT: improving efficiency of acid treatment of a well.

1 ex

FIELD: oil and gas industry.

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EFFECT: reduced core permeability.

1 dwg, 7 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: lubricating additive for drilling mud, characterised by it is prepared by mixing polyglycol, a floatation agent - oxal, isopropyl alcohol and tall oil at 50-60°C for 2 hours, adding a mixture of a fatty acid methyl ether and diethanolamide of coconut oil, then triethanolamine, raising the temperature to 75-80°C and mixing for 2 hours, adding copper or copper-calcium stearate and oxyethylated nonylphenol, mixing for 1 hour and adding a neutralising agent to pH not lower than 6.5, with the following ratio of components, wt %: polyglycol 27.3, isopropyl alcohol 9.1, floatation agent - oxal 24.3, tall oil 24.3, copper or copper-calcium stearate 3, triethanolamine 4.5-5, fatty acid methyl ether 1-1.5, diethanolamide of coconut oil 1, oxyethylated nonylphenol 3-4.5, neutralising agent 0.5-2.

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2 tbl, 2 ex

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil-extracting industry, in particular to methods of insulation of inflow of formation waters and lining of the bottomhole zone of formation, and also to the methods for adjustment of profile of acceleration performance of injection wells, to the methods for formation treatment, to the methods for regulation of development of oil fields, and can be used for elimination of leakage of production strings and creation of behind-the-casing filter, for elimination of behind-the-casing gas-manifestations, tubing-casing pressure and inter-formation overflows in behind-the-casing space of a well. The method of insulation of inflow of formation waters and lining of the bottomhole zone of formation includes injection of mix of siliceous substance with high-disperse hydrophobic material. Also the alkaline drain of ShchSPK caprolactam production is injected. The siliceous substance are organic-silicon oil-soluble and water-soluble substances or organic-silicon substances with the following ratio of components, wt %: organic-silicon oil-soluble and water-soluble substances or organic-silicon substances 44.9-77.0; high-disperse hydrophobic materials 0.1-3.0; alkaline drain of caprolactam production 20.0-55.0.

EFFECT: increase of insulation of inflow of waters and lining of the bottomhole zone, increase in the oil-sweeping ability of injected compositions possessing plastic properties unlike a prototype, necessary for more effective elimination of the problem of sand production, elimination of leakage from production strings and creation of the behind-the-casing filter.

7 cl, 4 tbl, 5 ex

FIELD: oil and gas industry.

SUBSTANCE: acid composition for treatment of bottom-hole zone of carbonate reservoir contains in wt %: inorganic or organic acid, or their mixtures 9.0-24.0; zwitterion surface-active substance - alkyl betaine 1.0-10.0; hydrophobically-modified urethane polymer 0.05-3.0; water - rest. The acid composition can additionally contain anionic surface-active substance in amount of 0.1-3.0 wt %.

EFFECT: alignment of injectivity profile of injection or inflow profile of the production wells in carbonate reservoirs with non-uniform permeability, creation of new fluid conducting channels through entire perforated thickness of the reservoir, restoration of reservoir characteristics of bottom-hole zone due to its cleaning of mud solid particles, increased thermal stability of injected acid composition.

2 cl, 1 tbl, 16 ex, 4 dwg

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

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

FIELD: chemistry.

SUBSTANCE: invention relates to liquids for the hydraulic fracturing of subterranean formations in oil and gas extraction. The method of applying liquid for hydraulic fracturing in the formation of fracturing of subterranean formations includes the retardation of polymer splitting in the liquid for hydraulic fracturing at a temperature from 125 to 400°F, when the liquid for hydraulic fracturing contains a liquefier, by the combination of at least one radical acceptor with the liquid for hydraulic fracturing. The mixture for the application in the liquid for hydraulic fracturing contains a radical acceptor and a liquefier. The method of the hydraulic fracturing of subterranean formation includes the supply of the liquid for hydraulic fracturing, containing a propping means, a polymer and the liquefier, addition of the radical acceptor, supply of the liquid to a desired location in a subterranean formation to form at least one hydraulic fracturing, making it possible for the liquefier to split the polymer and reduce the viscosity of the liquid for hydraulic fracturing at a specified time or at a specified temperature. The invention is developed in dependent claims.

EFFECT: increase of viscosity control efficiency.

15 cl, 1 dwg, 1 ex

FIELD: mining.

SUBSTANCE: plugging material comprises portland cement, microdispersed and expansion additives, fluid loss additive, the setting accelerator and water. The composition comprises the microdispersed and expansion additives as microdispersed cement complex MDCC consisting of: micro-cement or silica, or metakaolin and calcium hydrosulphoaluminate in a weight ratio of 2:1, respectively; the fluid loss additive - as water binding complex WBC consisting of a copolymer vinyl acetate and ethylene with vinyl acetate groups content of 18-20%, hydroxyethyl cellulose and modified organosilicon reagent in a weight ratio of 10:1:0.5, respectively; and the composition comprises the setting accelerator as calcium chloride or sodium chloride, in the following ratio of components, parts by weight: portland cement: 75-95; MDCC 5-25; WBC 2.0-3.5; the said setting accelerator 0.1-3.0; water 47-60.

EFFECT: increase in adhesion, strength characteristics, reduction of filtrate return and dynamic shear stress, improvement of indices of water and gas-blocking properties of the plugging material and formed cement stone.

2 tbl

FIELD: mining.

SUBSTANCE: insulating composition for protection from intensive absorption in the intervals of fissured rocks, comprising cement foam material CFM of grades A, B, C and D, water and setting accelerator, characterised in that the composition additionally comprises a plasticiser and a foam stabiliser, at that it comprises the setting accelerator as a mixture of potassium chloride and sodium carbonate in a weight ratio of 1:1, respectively, the foam stabiliser - as a mixture of low molecular weight hydroxyethyl cellulose and ethoxylated nonylphenol with 9 carbon atoms in the alkyl radical and 12 moles of ethylene oxide, attached to a mole of alkyl phenol, in a weight ratio of 0.4:1, respectively, and the plasticiser - as high-molecular anionic surfactant sodium polycarboxylate in the following ratio of components, mass parts: CFM - 100.0; the said setting accelerator - 8.0-12.0; the said foam stabiliser - 0.5-0.7; the said plasticiser - 0.5-0.9; water - 50.0-60.0.

EFFECT: increase in the insulating properties in elimination of absorption by reducing the setting time, increase in the strength and adhesion properties, increase in resistance to erosion.

2 tbl

FIELD: chemistry.

SUBSTANCE: method employs a polymer matrix based on metathesis-radically cross-linked mixture of oligocyclopentadienes. The polymer matrix has the following components, wt %: polymer stabiliser - 0.1-3.0, radical initiator - 0.1-4.0, ruthenium catalyst for metathesis polymerisation of dicyclopentadiene - 0.001-0.02, mixture of oligocyclopentadienes - the balance. After stirring at 0-35°C for 1-40 min, the mixture is added in the form of a laminar stream to an aqueous solution of a thickener. The thickener contains surfactants, has viscosity of 5-500 cP and temperature of 5-50°C. The formed microspheres are separated, heated in a medium of an inert liquid to 150-340°C and held for 1-360 min. The inert liquid used is heat-resistant silicone oil or synthetic mineral oil.

EFFECT: high output of microspheres and reduced swelling in oil.

5 cl, 32 ex

FIELD: production and exploratory well drilling, particularly foaming drilling fluids used during penetration through incompetent rock intervals and during primary productive oil and gas deposit opening in the case of abnormally low formation pressure.

SUBSTANCE: foam composition comprises surfactant, foam stabilizer, water, water hardness control additive and lubricant. The water hardness control additive is sodium silicate. The lubricant is VNIINP-117 emulsion. The foam stabilizer is polyacrylamide, the surfactant is sulphonole. All above components are taken in the following amounts (% by weight): sulphonole - 0.8-1.5, sodium silicate - 0.2-0.5, polyacrylamide - 0.1-0.5, VNIINP-117 - 0.5-2, remainder is water.

EFFECT: reduced power inputs for well drilling, as well as reduced coefficient of friction between drilling tool and well wall.

1 tbl

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