Acid composition for treatment of wells in carbonate and terrigenous reservoirs, and acid treatment method of bottom-hole zone of formation with its application

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

 

The invention relates to the oil and gas industry, in particular to compositions and methods acid treatment of bottom-hole zone of terrigenous and carbonate reservoirs, including low-permeability Sandstone reservoirs with high carbonate content (carbonate 5% or more), and heterogeneous reservoirs, and can be used in the process of boosting production and injection wells, as well as in large-acid treatment and hydraulic fracturing using acid solutions.

It is known that acid compositions containing organic solvents have the ability to align the reaction rate in the layer: slow reaction rate in water-saturated layers and accelerate them into oil-saturated layers due nefetmash properties of these solvents [Smykov centuries of Resource and energy saving technologies of oil production at the fields NGDU "Yamashneft", thesis for the degree of candidate of technical Sciences, Almetyevsk. - 2000].

The disadvantage of using these compositions in low-permeability reservoirs is that the use of these compounds leads to colmation collector due to the formation of precipitation and emulsion upon contact with acid composition and formation fluids, as well as secondary OS is cobracobana [Curtis Crowe, Jacques Marmontel, Ron Thomas, "Trends in acid treatment of the matrix", Petroleum review. Schlumberger. - Autumn. - 1996. S. 20-31 ].

Closest to the proposed invention the technical essence is a composition for acid treatment of bottom-hole formation zone of the next component composition, % wt.:

Alkylbenzenesulfonate3,5-5,5
Preparation of OS-202,5-5,5
Chlorine-containing reagent:
ammonium chloride3,5-6,5
24% inhibited hydrochloric acid14,0-18,0
Methanol12,0-16,0
Fusel oil4,0-8,0
Acetic acid6,0-12,0
Citric acid2,5-4,5
Corrosion inhibitor "IR-118"0,1-0,5
Fresh waterthe rest,

and the way the acid treatment of bottomhole saniplast, which includes sequential injection into the well of buffer fluid which is used is 1.5-3.0% solution of ammonium chloride, in amounts of 0.5-1.0 m31 m perforated formation thickness, and acid composition in an amount of 0.5-2.0 m31 m perforated formation thickness, its displacement in the reservoir using 1.0-3.0 m3the specified buffer liquid and the subsequent injection of fluid produce in the volume of the tubing, which is used a solution of fresh or saline water or water-in-oil emulsion or oil, extract the reaction for a period of not more than 8 hours and subsequent removal of the reaction products, the acid composition is used in the composition or solution obtained by dilution of the composition of fresh water or 3-24% solution of inhibited hydrochloric acid in the ratio of acid composition: fresh water or 3-24% solution of inhibited hydrochloric acid 1:1-1:9, respectively (prototype) [RF patent №2407769 published 27.12.2010, bull. No. 36].

The disadvantage of the composition and method of acid treatment of bottom-hole formation zone is the high corrosion rate of steel at elevated temperatures that can cause problems - high speed corrosion of underground equipment when using this composition in the reservoir with the reservoir temperature of 9°C and above, as well as the inefficiency of its application in heterogeneous reservoirs due to the low viscosity of the injected acid solution.

The invention is aimed at creating a structure for the acid treatment with low corrosion rate at formation temperatures, and method of processing heterogeneous reservoirs using a liquid-diverter hydrocarbon gel-based complex generouse "Himeko-N", and as the acid solution is developed acid composition, which will significantly increase the effectiveness of acid treatment in a heterogeneous carbonate, terrigenous or mixed collector.

The INVENTION

Proposed composition for acid production and injection wells in carbonate and terrigenous reservoirs containing hydrochloric acid, alkylbenzenesulfonate containing alkyl group of 12 to 14 carbon atoms, citric acid, acetic acid, methyl alcohol, drug, OS-20, the corrosion inhibitor of the type "DEW-118" and the water, which optionally contains methenamine and may contain fluoride-hydrogen acid and stabilizer iron type Ferix" in the following ratio of components:

Hydrochloric acid (24% or 36%)25,0-50,0
Alkylbenzenesulfonate0,1-2,0
Acetic acid3,0-12,0
Citric acid0,5-3,0
Fluoride-hydrogen acid (40%)0,0-7,5
Preparation of OS-200,5-2,5
Methanol3,0-10,0
Corrosion inhibitor "IR-118"1,0-5,0
Methenamine0,1-3,0
The stabilizer of iron "Verix"0,0-5,0
Waterthe rest,

and the way the acid treatment of collectors, including injection into the well of the proposed acid composition, as well as its solutions in fresh water at a ratio of composition: fresh water equal to 1:1-1:2, respectively, in the amount of 1.0-5.0 m31 m perforated formation thickness, its displacement in the reservoir, the shutter speed on the reaction for a period of not more than 8 hours and subsequent removal of the reaction products, and in the case of inhomogeneous manifold way the acid treatment includes pre-Zack the ku in the well fluid diversion in the amount of 0.5-2.5 m 31 m perforated thickness of the reservoir, the fluid-whipstock is used hydrocarbon gel-based complex generouse "Himeko-N and diesel fuel. For research were used:

1. Inhibited hydrochloric acid containing 24% of the mass. hydrochloric acid (Hcl), produced according to TU 2122-131-05807960-97 and acid synthetic technical, containing 36% of the mass. HCl is produced according to GOST 857-95.

2. Alkylbenzenesulfonate, mark And containing 97,0% of the mass. the main substance produced according to TU 2481-036-04689375.

3. Acetic acid, containing not less than 99.5% of the mass. the basic substance, is produced according to GOST 19814-74.

4. Citric acid, "am", contains not less than 99.0% mass. the basic substance, is produced according to GOST 3652-69.

5. Hydrofluoric acid (HF) containing 40% of the mass. HF is produced according to GOST 10484-78.

6. Preparation of OS-20, mark a, is a ethoxylate natural higher fatty alcohols fraction C16-C18produced according to GOST 10730-82.

7. Methanol with a concentration of 99.9%, manufactured according to GOST 2222-95.

8. Corrosion inhibitor "IR-118", is a glycolic solution of surfactants and Quaternary ammonium salts produced according to TU 2415-020-54651030-2007.

9. Methenamine concentration 98,0%, is produced according to GOST 1381-73.

10. The stabilizer of iron "Verix" represents composers who s on the basis of salts of organic acids, produced according to TU 2458-023-54651030-2007.

11. Oil North Pokachi field, reservoir UV, density at 20°C, ρ20=841 kg/m3and kinematic viscosity at 20°C - 6,11 mm2/c.

12. Kerosene TS.

13. The model produced water in the North-Pokachi field, reservoir UV, density - 1023 kg/m3total mineralization - 43,10 g/l

14. The fresh water.

Examples of the preparation of acid composition

Example 1

In a glass of 250 ml in 66,8 ml water dissolve 0.5 g of citric acid, 3.0 g of methanol, 3.0 g of acetic acid, 25,0 g 24% hydrochloric acid, 0.1 g of alkylbenzenesulfonate, 0.5 g of the drug OS-20, 1.0 g of corrosion inhibitor "IR-118", 0.1 g of methenamine and stirred until complete dissolution.

After stirring the obtained composition with the following composition of ingredients, % mass.:

Water66,8
Hydrochloric acid (24%)25,0
Alkylbenzenesulfonate0,1
Acetic acid3,0
Citric acid0,5
Preparation of OS-200,5
Meth is Nol 3,0
Corrosion inhibitor "IR-118"1,0
Methenamine0,1

Example 2

In a glass of 250 ml of 38.5 ml of water was dissolved 1.5 g of citric acid, 6.5 g of methanol, 7.5 g of acetic acid, of 33.0 g of 36% hydrochloric acid, 1.0 g of alkylbenzenesulfonate, 1.5 g of the drug OS-20, 3.0 g of corrosion inhibitor "IR-118", 1.5 g of methenamine, 3.5 g of a fluorine-hydrogen acid, 2.5 g of stabilizer iron "Ferix and stirred until complete dissolution.

After stirring the obtained composition with the following composition of ingredients, % mass.:

Corrosion inhibitor "IR-118"
Watera 38.5
Hydrochloric acid (36%)33,0
Alkylbenzenesulfonate1,0
Acetic acid7,5
Citric acid1,5
Fluoride-hydrogen acid (40%)3,5
Preparation of OS-201,5
Methanol6,5
3,0
Methenamine1,5
The stabilizer of iron "Verix"2,5

Example 3

In a glass of 250 ml to 50.0 ml of 36% hydrochloric acid was dissolved 3.0 g of citric acid, 10.0 g of methanol, 12.0 g of acetic acid, 2.0 g of alkylbenzenesulfonate, 2.5 g of the drug OS-20, 5.0 g of corrosion inhibitor "IR-118", 3.0 g of methenamine, 7.5 g of a fluorine-hydrogen acid, 5.0 g of stabilizer iron "Ferix and stirred until complete dissolution.

After stirring the obtained composition with the following composition of ingredients, % mass.:

Hydrochloric acid (36%)50,0
Alkylbenzenesulfonate2,0
Acetic acidto 12.0
Citric acid3,0
Fluoride-hydrogen acid (40%)7,5
Preparation of OS-202,5
Methanol10,0
The corrosion inhibitor is the IR-118" 5,0
Methenamine3,0
The stabilizer of iron "Verix"5,0

Example 4 (prototype, composition No. 3 in table 1)

In a glass of 250 ml 37.9 ml water dissolve 3.5 g of ammonium chloride, 2.5 g of citric acid, 16.0 g of methanol, 8.0 g of fusel oil, 12.0 g of acetic acid, 14.0 g of 24% hydrochloric acid, 3.5 g of alkylbenzenesulfonate, 2.5 g of the drug OS-20, 0.1 g of corrosion inhibitor "IR-118, and stirred until complete dissolution.

After stirring the obtained composition with the following composition of ingredients, % mass.:

Waterof 37.9
Ammonium chloride3,5
Citric acid2,5
Methanol16,0
Fusel oil8,0
Acetic acidto 12.0
Hydrochloric acid (24%)14,0
Alkylbenzenesulfonate3,5
Drug OS-20 2,5
Corrosion inhibitor "IR-118"0,1

The content of acid components in the compositions shown in table 1.

Table 1
The content of acid components in the compositions
№ p/pThe components in the calculation of the base materialContents in the acid composition, % mass.
Non examples
1234(prototype)
1Hydrochloric acid 24%25,0--14,0
2Hydrochloric acid 36%-33,050,0-
3Ammonium chloride-- -3,5
4Alkylbenzenesulfonate0,11,02,03,5
5Acetic acid3,07,5to 12.0to 12.0
6Citric acid0,51,53,02,5
7Fluoride-hydrogen acid 40%0,03,57,5-
8Preparation of OS-200,51,52,52,5
9Methanol3,06,510,016,0
10Fusel oil- --8,0
11Corrosion inhibitor "IR-118"1,03,05,00,1
12Methenamine0,11,53,0-
13The stabilizer of iron "Verix"0,02,55,0-
14Fresh water66,8a 38.50,0of 37.9

The lower limit of the concentration of alkylbenzenesulfonate and drug OS-20 is determined by the required interfacial tension acid composition on the border of the hydrocarbon phase (not more than 2.0 mn/m) and the upper - economic feasibility. The content of organic acids, hydrochloric and fluoride-hydrogen of the acid is determined by the dissolution rate of the species during the reaction. The methanol content is determined by the requirements to the temperature of sustiva the Oia - not higher than -35°C. the Content of urotropine and corrosion inhibitor is determined by the requirements of corrosion rate of steel at 20°C and at 90°C. the stabilizer Content of iron "Verix" is defined by the ability of the composition to form precipitation in the interaction with the reservoir oil content in acid ferric ions.

In laboratory conditions defined by the following properties of the proposed structure: the ability to prevent the formation of emulsions and precipitation when mixed with the hydrocarbon phase, and the interfacial tension at the phase boundary between the proposed structure and hydrocarbon phase; the corrosion rate of steel in the proposed composition at 20 and 90°C; the rate of dissolution of carbonate rocks, quartz and bentonite clay at a temperature of 90°C, characteristic fields in Western Siberia.

The ability of the proposed formulations to prevent the formation of emulsions and precipitation of asphalt-resin-paraffin substances when mixed with the hydrocarbon phase is determined by the separation of the aqueous and hydrocarbon phases after shaking equal volumes of hydrocarbon phase and an acid composition containing 5000 ppm of ions Fe3+in a graduated test tube, followed by heating to 90°C (reservoir temperature) and curing at a given temperature for 30 minutes with the last is the missing spilling the contents of the tube through a sieve with mesh size 0,149 mm. In the case of formation of the emulsion is incomplete separation of the system into phases, and in the allocation of precipitation is the precipitation of the precipitation on the sieve after spilling through him the contents of the test tube.

Interfacial tension, mn/m, on the border with the hydrocarbon phase (kerosene TS-1) for the tested compounds is determined using the automatic part of the stalagmometer AGC 2.784.001 according to the method supplied with the device.

Steel corrosion rate, g/m2·h, is determined in accordance with generally accepted technique for losing weight plates of steel grade St3 size 25,0×20,0×0.5 mm after soaking them for 24 hours to test the acid solution at 20°C and for 1 hour at 90°C.

Dissolving ability of the proposed structure and composition of the prototype in relation to the breed is investigated on the example of the dissolution of carbonate rocks (for composition without HF content) or quartz (for the composition containing HF) and bentonite clay at a temperature of 90°C.

Testing by the dissolution of carbonate rocks or quartz are carried out according to the method, according to which the amount of acid solution (ml) 2.5 times the surface area (cm2) cube rocks with hand 16-20 mm, or quartz cylinder with a diameter of 10 and a length of 20 mm After production of approximately equal size cubes breed or cylinders are placed in the drying Cabinet is, where are aged for two hours, and then weighed on an analytical balance with accuracy to 0.0001, the Subject acid composition poured into Teflon beakers, and then immersed inside the cubes or cylinders at a fixed contact time of 60, 120 and 240 minutes.

After a time of contact of the specimen of the breed, it is removed from the solution, washed with distilled water and placed in an oven for two hours. This allows you to observe the dissolution of carbonate rocks and quartz as expenditure acid.

Solubility in percent is calculated by the formula:

Pp(m1-m2)·100%/m1,

where m1- the mass of the cube or cylinder to the experience, g;

m2- the mass of the cube or cylinder after the experience,

For testing the dissolution of bentonite clay, there are three filter paper and three hanging clay 2.0 g Sample dried to constant weight at 105°C, then the clay is transferred to filter paper and weighed on an analytical balance with accuracy to 0.0001, the Number of acid solution (ml) 2.5 times greater than the mass of sample in grams. Filters with clay are placed in a Teflon funnel, mounted on a Teflon Cup with a volume of 100 ml, then the whole system is placed in a heat chamber. Within 15 minutes of the test solution was heated in a phone is about the glass at a temperature of 90°C, then in the first funnel is filled with the solution and within 5 minutes is the dissolution sample of clay in this part of the solution filtered. The obtained filtrate is transferred into a second funnel to dissolve the following sample clay, the duration of the second filter is 10 minutes. Next, the filtrate is transferred to the dissolution of the third hinge clay, duration of filtration which is 15 minutes.

After filtration of the spent clay portions washed with distilled water in an amount of 200 ml at a temperature of 90°C. then the samples are dried in a drying Cabinet at 105°C to constant mass.

The solubility of the clay percentage is calculated by the formula:

Pg=(m1-m2)·100%/m1,

where m1- weight of clay to experience, g;

m2- weight of the clay after the experience,

In our experiments we used the oil of the North-Pokachi field, reservoir UV, density at 20°C, ρ20=841 kg/m3and kinematic viscosity at 20°C - 6,11 mm2/s and kerosene TS-1. The results are shown in table 2.

Research emulsifying ability of the proposed acid composition showed that when interacting with oil and kerosene TS-1 emulsion is not formed: a mixture of oil (or TS-1) and the proposed structure (compounds 1-3 in table 1, and their RA who works in fresh water at a ratio of composition: fresh water, equal to 1:1-1:2, respectively) after shaking completely separated into aqueous and hydrocarbon phases within 5-30 min, and the subsequent spilling of the contents of the tube through a sieve with mesh size 0,149 mm not leave any traces.

Table 2
Properties of acid composition
No. composition in table 1Interfacial tension on the border with TS-1, mn/mThe corrosion rate, g/m2·hThe dissolution of carbonate rocks or quartz at 90°CThe dissolution of clay at 90°C
at 20°Cat 90°CThe contact time, minShare proreagirovali-
our breed %
The contact time, minThe dissolution of clay %
1*0,160,1413,260
120
240
1,96
4,63
6,51
154,36
2*0,150,1210,260
120
240
0,35
0,84
1,99
155,12
1*0,130,119,460
120
240
0,89
1,79
4,22
158,35
4* placeholder0,160,1616,460
120
240
1,26
3,72
6,03
15as 4.02
* Note: for compounds 1 and 4 shows the dissolution of carbonate rocks, and for compositions 2 and 3 show the dissolution of quartz (simulating terrigenous collector), compounds 1 and 4 quartz does not dissolve.

As follows from table 2, at a temperature of 90°C, the rate of dissolution of carbonate rocks of the proposed acid composition (composition 1) is higher than that of the composition of the prototype, and after 240 minutes after the start of the reaction both composition capable of maintaining a sufficiently high rate of dissolution of the breed. Compounds 2 and 3, containing the s fluoride-hydrogen acid, dissolve and also quartz cylinders, while composition 1 and composition prototype quartz does not dissolve. Upon the dissolution of bentonite clay composition 1 behaves similarly to the prototype, and compounds 2 and 3 show a much greater solvent power than the composition of the prototype, this is due to the presence of fluoride-hydrogen acid.

During the reaction and proposed structures, and the structure of the prototype does not form insoluble precipitates. The proposed compositions similar to the composition of the prototype have low values of interfacial tension on the border with kerosene TS-1 and low corrosion rate at 20°C, while the proposed formulations have a lower corrosion rate at 90°C compared with the composition of the prototype, which will increase the effectiveness of acid treatment.

When evaluating the interaction between the acidic compositions containing 5000 ppm of ions Fe3+with oil North Pokachi field, it was found that despite the content in compositions 2 and 3 fluoride-hydrogen acids, they do not form precipitation on the filter.

For the practical application of the proposed method the acid treatment of bottom-hole zone of carbonate, or mixed terrigenous formation comprising pumping into the well a proposed acid composition, as well as its solutions in fresh water at a ratio of SOS is AB: fresh water, equal to 1:1-1:2, respectively, in the amount of 1.0-5.0 m31 m perforated formation thickness, its displacement in the reservoir, the shutter speed on the reaction for a period of not more than 8 hours and subsequent removal of the reaction products, and in the case of fractured or inhomogeneous manifold acid treatment method includes a preliminary injection into the well fluid diversion in the amount of 0.5-2.5 m31 m perforated thickness of the reservoir, the fluid-whipstock is used hydrocarbon gel-based complex generouse "Himeko-N and diesel fuel.

Table 3 presents the results of the filtration experiment proposed acid composition on the sample core - seal off low-permeability Sandstone.

Table 3
№ p/pThe composition of the fluid exposureComponent quantityThe permeability of the sample solution of ammonium chloride, μm2
before exposureafter exposure
1Injection model of the reservoir water of the North-Pokachi, mostorod the tion, density at 20°C-1021 kg/m3To stabilize the differential pressure
2Pumping oil North Pokachi field density at 20°C - 841 kg/m3To stabilize the differential pressure
3Injection of 3% solution of ammonium chloride in the forward directionTo stabilize the differential pressure0,027
4Injection of composition No. 2 (table 1)10 pore volumes
5Injection of 3%-aqueous solution of ammonium chloride in the opposite directionTo stabilize the differential pressure0,089

As follows from the presented data, the processing of the low-permeability core solution proposed acid composition can significantly increase its permeability.

1. Acid composition for acid treatment is TCA production and injection wells in carbonate and terrigenous reservoirs, containing hydrochloric acid, alkylbenzenesulfonate containing alkyl group of 12 to 14 carbon atoms, citric acid, acetic acid, methyl alcohol, drug, OS-20, the corrosion inhibitor of the type "IR-118, and water, characterized in that it further contains methenamine and may contain hydrofluoric acid and stabilizer iron type Ferix" in the following ratio of components, % wt.:

Hydrochloric acid (24% or 36%)25,0-50,0
Alkylbenzenesulfonate0,1-2,0
Acetic acid3,0-12,0
Citric acid0,5-3,0
Hydrofluoric acid (40%)0,0-7,5
Preparation of OS-200,5-2,5
Methanol3,0-10,0
Corrosion inhibitor "IR-118"1,0-5,0
Methenamine0,1-3,0
The stabilizer of iron "Verix"0,0-5,0
Waterthe rest of it.

2. The way the acid treatment of bottom-hole zone of carbonate, terrigenous or mixed layer, including injection into the borehole acid composition in an amount of 1.0-5.0 m31 m perforated formation thickness, its displacement in the reservoir, the shutter speed on the reaction for a period of not more than 8 hours and subsequent removal of reaction products, wherein as acid composition composition is used under item 1, as well as its solutions in fresh water at a ratio of composition : fresh water equal to 1:1-1:2, respectively.

3. The way the acid treatment of bottom-hole zone of carbonate, terrigenous or mixed layer under item 2, characterized in that it includes a preliminary injection into the well fluid diversion in the amount of 0.5-2.5 m31 m perforated thickness of the reservoir, the fluid-whipstock is used hydrocarbon gel-based complex generouse "Himeko-N and diesel fuel.



 

Same patents:

FIELD: oil and gas industry.

SUBSTANCE: in this method of acid longitudinal hydraulic fracturing of low-permeable terrigenous collector to inner cavity of the production casing a slot perforator is run in, walls of the production casing are cut by means of vertical disc cutters of the slot perforator with forming of two longitudinal slots opposed at different height points within the interval from the foot to the roof of the producing formation. Through jet nozzles of the slot perforator hydrocarbon-based process fluid is injected and through longitudinal slots in the production casing the process fluid is washed at pressure that does not exceed pressure of hydraulic fracturing and filtration channels are thus formed in cement stone behind the production casing and ambient rock in the bottom-hole zone of the formation, which pass deep into the producing formation. Upon formation of the filtration channels the slot perforator is removed and downhole equipment consisting of a high-pressure packer and a circulating valve is run in to the well at the flow string. The packer is packed over the roof of the producing formation and filtration channels are washed with hydrochloric acid of 12% concentration with flushing to the producing formation depth of hydrocarbon-based process fluid injected to the well earlier. Thereafter below-packer space of the well is flushed by thickened mud acid consisting of hydrochloric acid of 12% concentration, hydrofluoric acid of 3% concentration and mud thickener of carboxymethyl cellulose to the formation depth as fracturing fluid and proppant material with formation of fractured slot. Upon completion of acid hydraulic fracturing and fixation of fractured slot, the slot is washed by hydrochloric acid of 12% concentration with destruction of mud thickener of carboxymethyl cellulose. Then the over-packer space of the well is washed by creating circulation in annular space and tubing space by means of the circulating valve and influx is induced from the producing formation by reduction of backward pressure. Upon development the well is introduced into operation with remaining downhole equipment, which was run in to the well during process of hydraulic fracturing.

EFFECT: increased square area and depth of the producing formation penetration at elimination of swelling conditions for clays contained in the reservoir.

3 ex, 7 dwg

FIELD: oil and gas industry.

SUBSTANCE: well completion method involves pumping of an acid solution by circulation with a well mouth by means of a jet nozzle arranged on the end of a flexible flush-joint pipe. Simultaneously with circulation of the acid solution, the flexible flush-joint pipe is being lifted out of the well at a speed that is not higher than the speed of filling the well shaft with an acid solution. After the horizontal shaft is filled with the acid solution, squeezing of the acid solution to the formation is performed at stepped pressure rise and exposure at each step. Process exposure is performed for a reaction of the acid solution with the rock, and inert gas pumping, fixing of a level recovery curve, well killing and well development is performed. First, a tubing string with starting clutches and with a funnel on the end is lowered into the well at the interval of the shoe of the production casing. The flexible flush-joint pipe with a jet nozzle is lowered inside the tubing. Before the acid is pumped to the formation, the horizontal shaft of the well at an open annular space is filled through the flexible flush-joint pipe with a water solution of a surface active substance (SAS). When the annular space is closed, the water solution of SAS is pumped to the formation. Process exposure is performed before oil floats up into the well. Then, the acid solution is pumped via the annular space. Process exposure is performed for 2-4 hours for the reaction of the acid solution with the rock. The well shaft is flushed. The flexible flush-joint pipe with the jet nozzle is lifted out of the well. Inert gas pumping is performed via the annular space with liquid take-off via the tubing.

EFFECT: improving efficiency of acid treatment of a well.

1 ex

FIELD: oil and gas industry.

SUBSTANCE: well completion method includes the injection of an acid solution by circulation with the wellhead by means of a jet nozzle placed at the end of a flexible flush-joint pipe, simultaneously with the acid solution circulation lifting of the flexible flush-joint pipe with a rate that does not exceed the rate of the borehole filling with the acid solution, upon filling of a horizontal borehole with the acid solution flushing of the acid solution to the formation with the staged pressure increase and the process withhold at each stage for the purpose of acid reaction with rock, injection of inert gas, recording of the level recovery curve, well killing and well development. A tubing string with starting clutches and with a funnel on the end is lowered into the well preliminarily at the interval of the shoe of the production casing. The flexible flush-joint pipe with the jet nozzle is lowered inside the tubing. Before the acid is flushed to the formation, the horizontal shaft of the well at an open annular space is filled through the flexible flush-joint pipe with a water solution of a surface active substance (SAS). At the closed annular space the water solution of the surface active substance is flushed to the formation, the process is withheld till oil flowing to the well. Then through the annular space the acid solution is flushed, the process is withheld for the purpose of the acid reaction with the rock, the borehole is washed, the flexible flush-joint pipe with the jet nozzle is lifted from the well. Inert gas injection is made through the annular space with the fluid sampling in the tubing string. Upon development of the well a geophysical survey is made for the horizontal borehole at the flexible pipe by thermometry and measurement by a flowmeter. Upon receipt of the survey results non-operated intervals are identified and by comparing geophysical data with final logging data non-operated intervals are identified in the horizontal borehole having high permeability and porosity. By running the flexible flush-joint pipe in, the jet nozzle is set in these intervals of the horizontal borehole, the jet nozzle end is thrusted to the horizontal borehole wall and the acid solution is circulated through the flexible flush-joint pipe, jet nozzle and tubing string until depression (channel) is formed in the rock and the surface area of the impact interval is increased. Then through the annular space the acid solution is flushed, the process is withheld for the purpose of the acid reaction with the rock, the borehole is washed, the flexible flush-joint pipe with the jet nozzle is lifted from the well. Inert gas injection is made through the annular space with the fluid sampling in the tubing string.

EFFECT: improving the acid treatment efficiency.

1 ex

FIELD: oil and gas industry.

SUBSTANCE: in the method acid process composition is injected to the well, withheld for reaction with further removal of reaction products from the formation. Before injection of the acid process composition, upon the last running in of tool for washing of the borehole before development a mixture of non-ionic surfactant with sulphamic acid at mass ratio of 0.003-0.005:1 in quantity of 1-3 wt % is introduced to drill mud containing high-molecular compounds and colmatant used for opening and washing of the producing formation. Then, upon the last running out of tool from the well and running in of tubing string the above drill mud is replaced by the acid process composition and the latter is withheld for reaction during at least four hours. The acid process composition consists of the following ingredients, by wt %: peroxide compound 0.5-3.0; sulphamic acid 5.0-10.0; non-ionic surfactant 0.005-0.02; mineralized water takes the remaining share. Density of the above process composition is equal to density of the drill mud used at opening of the producing formation or differs from it less than per 10%.

EFFECT: improved efficiency and producibility of colmatage removal from the bottomhole zone of the producer borehole, including inclined and horizontal wells, upon usage of the process fluid containing high-molecular compounds and colmatants.

7 cl, 4 tbl, 2 ex

FIELD: oil and gas industry.

SUBSTANCE: invention aims at restoring filtration characteristics of bottom hole areas of oil-and-gas wells disturbed while in service, with the use of hydroreactive metals. A method for the thermal-chemical treating of the bottom hole area of the well in the routine cycle mode: sodium feed in aluminium barrels enclosed in a hermetically sealed container onto the bottom hole, initiating a reaction of the above metals, keeping, lifting up the container in the hesitation mode equal to 5-10 min, descending the container at 0.2-1 m/minute.

EFFECT: more effective exposure for greater-depth productive formations and cost saving.

1 tbl, 1 ex

FIELD: mining.

SUBSTANCE: method comprises the formation exposing by vertical well, tripping in the well on the pipe string of the water jet tool with even amount of injection nozzles and its placement in the preset interval of the formation, injection of driving fluid through injection nozzles of the water jet tool for caving in the formation, subsequent formation fracturing from caverns by the spray stagnation pressure in caverns. Meanwhile the water jet tool with a series of injection nozzles, located along the tool with the interval between nozzles in a line no more than two diameters of the casing is used. The water jet tool is rotated to the preset angle to change the direction of progressing of each subsequent fracture. The fractures are formed at driving fluid injection pressure in the casing below the side rock pressure. Before tripping of pipe string into the well in the bottom end of the water jet tool the rotating device and mechanical packer are installed. To compensate leakages and the wedging of fractures during the process of hydraulic formation fracturing an acid is added in volume equal to 20% of the volume of the driving fluid, the driving fluid is injected into the pipe string through the water jet tool into a cavern until fracturing, then into the annular space of the well an acid is injected to compensate the leakages and fracture wedging. The pressure of acid injection into annular space of the well amounts 85% from the pressure created in the pipe string during progressing of fracture, upon termination of progressing fracture and the wedging of fracture in the same direction raise a pipe string on 1 m, turn a pipe string on an angle applicable to a direction of forming of following fracture, and lowered, then the process operations are repeated.

EFFECT: improvement of accuracy of orientation of fractures, performance and reliability of fracturing of carbonate reservoirs.

3 dwg

FIELD: mining.

SUBSTANCE: method comprises the drilling of a horizontal well bore in oil saturated part of the productive formation of the well, tripping of the pipe string into the well, the forming of perforations and fractures using the a hydrofracturing of formation in the hole of horizontal well, successively, starting from the end of far from the vertical borehole axis. During the next hydrofracturing the section, through which hydrofracturing is performed, is insulated from another part of the string with a packer. During drilling of the horizontal well bore the permeability and porosity of rocks are determined and the intervals of the productive formation with low permeability and porosity of rocks are identified, and on completing of drilling the rock hydrofracturing pressure is determined in each interval of the horizontal borehole. Then the volumes of fracturing fluid and acid for each interval of the oil saturated part of the formation with low permeability and porosity are determined, then the pipe string is moved to the interval of the productive formation nearest to the borehole bottom, with low permeability and porosity, the mechanical packer is seated, from hole mouth using the pumping unit the gelled fracturing fluid is injected into the pipe string through nozzles of the water jet tool and reshape perforations, then, not stopping injection gelled of fracturing fluid on a pipe string, construct fracture pressure applicable to the given interval of the oil saturated part of the productive formation. After 30% drop of pressure of injection of gelled fracturing fluid in the pipe string the hydrofracturing fractures are formed, for this purpose into the annular space of the well an acid is injected at the variable flow rate ensuring maintaining of pressure of injection of gelled fracturing fluid in the pipe string 10% less than the fracture pressure for the given interval of the oil saturated part of the productive formation. The packer releasing is performed and the pipe string is removed from bottomhole to the mouth into the following interval of the oil saturated part of the formation with low permeability and porosity of rocks for forming perforations and conducting of a hydrofracturing of the formation with forming and progressing of fractures.

EFFECT: shortening time for formation hydrofracturing, improvement of performance and reliability of formation hydrofracturing.

3 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: method of treatment of the well bottomhole zone with low bed pressure means well washing with fresh water, renewal of the production formation perforation on the basis 10 holes per running meter of well, formations saturation with fresh water to 6MPa. The first portion of hydrochloric acid solution is injected to the well in amount 2.0m3 and is held under bath mode for 2 h. Injection to the formation is performed by four stages. At first stage 6 times pulse injection to the formation of specified first portion of hydrochloric acid solution is performed under cycle mode, including injection for 1 minute at pressure 1-6MPa and holding for 5 minutes for reaction, injection of the specified portion is completed under continuous mode until complete release of the well bore from the hydrochloric acid solution. At the second stage 6 times pulse injection to the formation of the second portion of the hydrochloric acid solution is performed in volume 3.0m3 under cycle mode, including injection for 1 minute at pressure 1-6MPa and holding for 5 minutes for reaction, injection is completed under continuous mode. Then process holding for 3 h is performed for reaction. At the third stage the third portion of the hydrochloric acid solution on the basis 0.5m3 per running meter of the production formation is performed under continuous mode at pressure 1-6MPa, and holding for reaction for 3 h is performed. At the forth stage the 6 times pulse injection to the formation of the second portion of the hydrochloric acid solution is performed on the basis 1.0m3 per running meter of the production formation under cycle mode including injection for 1 minute at pressure 1-6MPa and holding for 5 minutes for reaction, injection is completed under continuous mode. Holding for 3 h for reaction is performed, then reaction products are removed by swabbing.

EFFECT: improving treatment efficiency of the well bottom-hole zone.

1 ex

FIELD: oil-and-gas industry.

SUBSTANCE: proposed method comprises recovery of core, making of core specimens and their analysis at electronic scanning microscope. Chemical reagent is forced through prepared specimens and sections are made at entry and exit of said chemical reagent. X-ray tomography is used to analyse the core specimens after forcing though of said chemical reagent. Images are compared to isolate the most efficient forms of solution channels. Numerical value of acid processing efficiency is calculated by computer processing of characteristics of images produced with the help of tomographic scanner. Minimum numerical value of said efficiency is selected as a criterion of the highest efficiency of acid processing. Note here that magnitude of stimulation is used as the numerical value of acid processing efficiency. Note here that, first, software is used for automatic determination of bored hole propagation volume. Then, acid solution penetration depth is computed. Now, stimulation magnitude is calculated by mathematical formula.

EFFECT: higher accuracy of efficiency and control over acid processing, fast determination.

3 ex, 4 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: proposed process comprises pre-flushing of the well with organic solvent. Then, organic solvent and film-forming anger are injected in the well. Film-forming agent represents 5-30% solution of boiler fuel in hydrocarbon solvent in amount of 0.5-2.5 m3/m of the bed perforated depth. Organic solvent buffer is used in amount of 3-6 m3 and aid solution in amount of 1-5 m3/m of perforated bed depth, injected fluids being injected thereafter in the bed.

EFFECT: higher efficiency of processing.

2 tbl, 4 ex

FIELD: oil and gas industry.

SUBSTANCE: water-based composite for temporary blocking of a productive formation comprises carboxymethyl cellulose, calcium chloride, dibasic ammonium phosphate, Morpen and water, as well it contains additionally potassium chloride and zinc stearate with the following ratio of ingredients, wt %: carboxymethyl cellulose 0.5-3.0, calcium chloride 3-12, dibasic ammonium phosphate 5-15, Morpen 0.05-1.00, potassium chloride 0.1-1.0, zinc stearate 0.1-5.0, water - up to the remaining weight.

EFFECT: improved efficiency of temporary blocking, maintenance of the productive formation permeability and porosity, improved workability of the blocking process due to the usage of the composite with perfected thixotropic properties promoting smooth cross-bonding in the process of the composite making and creation of high hydraulic resistance at blocking that prevent deep penetration of the blocking composite liquid phase to the formation.

1 dwg, 5 ex

FIELD: chemistry.

SUBSTANCE: grouting composition for insulation of zones of intensive absorption, includes Portland cement, semi-water gypsum, clay, foam generator and water, it also additionally contains calcium chloride, hydroxyethylcellulose and inert additive. As clay composition contains palydorskite, either montmorillonite or kaolin thermally activated mud powder, and as foam generator, and anionic or amphoteric surface-active substance SAS, with the following component ratio, wt.p.: Portland cement 76.0-91.9; semi-water gypsum 4.0-16.0; said clay powder 4.0-20.0, inert additive 0.1-4.0, said foam generator 0.1-0.5; potassium chloride 4.0-12.0; hydroxyethylcellulose 0.1-0.2; with water-solid ratio 0.6-1.0, which mixture of Portland cement, semiwater gypsum, said clay powder and inert additive constitutes 100 wt.p.

EFFECT: increased degree of insulating properties of claimed composition with insulation of intervals of absorption of well liquids in porous, cavernous fractured rocks, with opening of conducting channels from 1 mm to 10 mm, due to reduced density and high composition thixotropy, as well as due to formation of non-erodible and non-permeable cement stone with high adhesive properties to rock and increased strength characteristics.

4 cl, 2 tbl

FIELD: oil and gas industry.

SUBSTANCE: magnesia plugging material comprises a magnesium-containing binding agent, magnesium chloride and additives, at that the builder's calcined magnesite is used as the magnesium-containing binding agent, among the additives it contains a water-repellent agent being silicone oil and a hardening retarder being nitrilotrimethylphosphonic acid with the following ratio of components, wt %: builder's calcined magnesite - 70-80, magnesium chloride - 20-30, silicone oil - 0.1-0.5% above 100%, nitrilotrimethylphosphonic acid - 0.02-0.1 above 100%.

EFFECT: improved rate of the solution hardening and strength of the produced cement stone.

2 cl, 3 tbl

FIELD: oil and gas industry.

SUBSTANCE: cement slurry for cementing oil and gas wells consists of Portland cement, penetrating agent, fluid loss reducing agent, plasticising agent, antifoaming agent and water and differs in the fact that its contains PenetronAdmix as penetrating agent, any water-soluble cellulose ester as fluid loss reducing agent, lignosulphonate as plasticising agent, tributyl phosphate as antifoaming agent with the following ratio of components, wt %: Portland cement - 100, the above penetrating agent 3.0 in excess 100, the above fluid loss reducing agent - 0.03-0.1 in excess 100, the above plasticising agent - 0.3-0.7 in excess 100, tributyl phosphate - 0.01-0.1 in excess 100, water up to water-cement ratio - 0.38-0.42.

EFFECT: recovering integrity of cement sheath in annular space of wells when microcracks and microgaps are formed in it.

1 tbl

FIELD: oil and gas industry.

SUBSTANCE: in the development method of a non-homogeneous oil formation that includes injection to the formation of an aqueous solution of polyacrylamide (PAA), chrome acetate and magnesium oxide, the solution contains additionally a glass or basalt reinforcing microfiber pretreated by a 1-5% aqueous solution of AF9-6 or AF9-12 or constructional reinforcing microfiber (CRF) with the following concentration of components in the solution, wt %: PAA 0.3-1.0, chrome acetate 0.03-0.1, magnesium oxide 0.015-0.07, the above fibre 0.1-0.5.

EFFECT: increased efficiency of the method.

1 dwg, 2 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: inhibitor of asphaltresinparaffin sediments, obtained with the application of an alkylacrylate copolymer and aromatic solvent, obtained by the interaction of the copolymer in toluene, which has the mol. weight 6000-8000, a mixture of alkylacrylates, which contain, wt %: alkylacrylate C16 - 65, alkylacrylate C18 - 25, alkylacrylate C20 - 10, with dodecylamine acrylate, and dodecylamine sulphate with heating with mixing to 80°C, introduction of a 8.8-16.6% solution of an azobisisobutyronitrile in toluene initiator, exposure for 5 hours at 90-100°C with the following component ratio, wt %: copolymer of the said mixture of alkylacrylates with dodecylamine acrylate 45-57, dodecylamine sulphate 2-3, toluene - the remaining part.

EFFECT: increased efficiency of preventing the formation of asphaltresinparaffin sediments in paraffinic, highly-paraffinic oils and gas condensates.

4 ex, 1 tbl

FIELD: oil and gas industry.

SUBSTANCE: compound for oil recovery factor improvement including aluminium chloride, carbamide, additive and water contains aluminium chloride of A-5 brand, carbamide of A brand and silicone fluid GKZH-11N as an additive with the following ratio of components, wt %: industrial aluminium chloride of A-5 brand 20-45, carbamide of A brand 25-40, GKZH-11N 1.0-5.0, water - the remaining share.

EFFECT: improving oil recovery factor of formations with high formation temperature due to redistribution of seepage flows, increasing sweep efficiency.

2 ex, 1 tbl

FIELD: mining.

SUBSTANCE: proposed mud fluid comprises the following components in wt %: clay powder - 4-8; shale stabilisers to make well walls stable, a tall oil - 5-15, filtration attenuator - 0.2-1, water making the rest.

EFFECT: better stabilising properties.

2 cl, 1 tbl, 1 dwg

Non-dispersing mud // 2541664

FIELD: chemistry.

SUBSTANCE: drilling mud contains, wt %: mud powder PBMV 2-3, polyelectrolyte VPK-402 2-4; clay inhibitor inhibiting composition Biosol 20-50; structure-forming agent and fluid loss reducing agent biopolymer Bioxan 0.05-0.15; water - the balance.

EFFECT: improved inhibiting properties of the mud while reducing consumption of polyelectrolyte VPK-402.

2 tbl, 1 dwg

FIELD: chemistry.

SUBSTANCE: claimed invention relates to cross-linked in meta positions phenolaldehyde resin, in which transverse bonds in meta positions are organic transverse bonds, formed by transition metal and organic fragments, bound to transition metal via at least four intermediate oxygen atoms, or transverse bonds in meta positions are inorganic bonds, including terminal parts, which contain rare earth element, and core, containing at least one transition metal, and each terminal part, containing rare earth element is bound to core, containing transition metal, by means of one or more O, N or S atoms. Also described is method of obtaining said cross-linked in meta positions phenolaldehyde resin, which includes combination of agent, cross-linking in meta positions, which contains transition metal or one or more source-compounds, capable of reacting with formation of such transition metal-containing cross-linking agent with phenolaldehyde resin, activated in meta positions by combination of phenolaldehyde resin with activator of meta positions, containing at least one rare earth element with at least one element of O, N and S, or with activator of meta positions, capable of substituting methylene bonds in phenolaldehyde resin with amine bonds, and having degree of incomplete cross-linking in ortho- and para-positions, equal to at least 2%, and transition metal-containing cross-linking agent represents organic compound, formed by transition metal and organic fragments, bound to transition metal via at least four intermediate oxygen atoms, or represents inorganic compound, including terminal parts, containing rare earth elements, and core, containing at least one transition metal, and each terminal part, containing rare earth element, is bound with transition metal-containing core by means of one or more O, N or S atoms. Described is proppant with resin coating, including particles of proppant substrate, covered with said cross-linked in meta positions phenolaldehyde resin. Described is material for obtaining proppant, containing residue, obtained by heating at temperature from 400°C to 600°C of said cross-linked in meta positions phenolaldehyde resin, obtained by formation in meta positions of inorganic transverse bonds, including terminal parts, which contain rare earth element, and core, which contains, at least, one transition metal, with each terminal part, which contains rare earth element, being bound with transition metal-containing core by means of one or more O, N or S atoms. Described is organometallic proppant, which includes proppant particles, including residue of decomposition of said phenolaldehyde resin, cross-linked in meta positions, and said residue of decomposition is obtained by heating at temperature from 400°C to 600°C to decompose cross-linked in meta positions phanolaldehyde resin, obtained by means of inorganic transverse bonds in meta-positions, including terminal parts, containing rare earth element, and core, containing at least one transition metal, and each terminal section, containing rare earth element, is bound with transition metal-containing core by means of one or more O, N and S atoms.

EFFECT: obtaining benzyl polymers, cross-linked in meta positions, obtaining based on them proppant, possessing improved crush strength, porosity and permeability.

35 cl, 8 dwg, 6 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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