RU2460875C1 - Carbonate formation hydraulic fracturing method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method involves lowering to the well of tubing string with packer and its further fit, lowering to tubing string of flexible tubing string below lower end of tubing string; pumping of water-insulating cement via flexible tube; hydraulic fracturing of carbonate formation with bottom water. Lower end of flexible tubing string is lowered to the level of water-oil contact (WOC); space is sealed between tubing string and flexible tubing string, insulation of bottom water is performed in carbonate formation by pumping of water-insulating cement via flexible tubing string with well filling from working face to WOC level. After that, space between tubing string and flexible tubing string is unsealed and flexible tubing string is lifted so that its lower end is 1-2 metres below roof of carbonate formation; after that, total volume of fracturing fluid is determined as per analytical expression. Space between tubing strings and flexible tubing strings is sealed and the first portion of fracturing fluid is pumped to flexible tubing string in the quantity of 60-70% of total fracturing fluid volume under the pressure of not more than 25 MPa and at the speed of not more than 2 m³/min. After that, the rest fracturing fluid volume is pumped to flexible tubing string in 3-5 cycles in turn with pumping of propping agent. As the latter there used is 25% inhibited chlorhydric acid. Volume of acid is determined depending on thickness of productive part of carbonate formation based on volume of 0.2 m³ of acid per 1 m of formation thickness per each pumping cycle. After the last pumping cycle is completed, acid is flushed with water solution of surface active substance in volume of flexible tubing string with further exposure during 1-2 h. Then, flexible tubing string is removed from tubing string and the well is brought into operation.

EFFECT: simpler and more effective method.

3 ex, 2 dwg

Description

The invention relates to the oil industry and may find application in hydraulic fracturing of a carbonate formation with bottom water.

A known method of processing waterlogged carbonate reservoirs (patent RU No. 2383724, IPC 8 ЕВВ 43/22, 43/27, published in Bulletin No. 7 of 03/10/2010), which includes pre-saturation of highly watered channels with a coagulant by injection of a 20% chloride solution calcium, the subsequent injection of a buffer layer of fresh water, then a solution of hydrolyzed in alkali waste fiber or polyacrylonitrile tissue - GOPAN, a buffer layer of fresh water and the implementation of hydrochloric acid exposure, while this injection is repeated, and in the first portion of the solution and GOPAN additionally introduces 0.1-1.0% of dry non-hydrolyzed ground wastes of polyacrylonitrile fiber, injects the first portion of the GOPAN solution at an injection pressure at the wellhead equal to 20% of the fracturing pressure of the treated formation, injects each subsequent portion of the GOPAN solution with an increase injection pressure at the wellhead relative to the previous one by 10% of the fracturing pressure of the treated formation, and the injection pressure should not exceed 50% of the fracturing pressure of the treated formation, each p the next portion of the GOPAN solution, starting with the third, is diluted with water in relation to the previous 2 times.

The disadvantages of this method are:

- firstly, low efficiency of oil flow intensification and enhanced oil recovery;

- secondly, the complex technological process of isolation of waterlogged carbonate reservoirs, and only exact observance of the indicated concentrations, pressures and a clear sequence of technological operations will allow for high-quality waterproofing.

The closest is the method of hydraulic fracturing (patent RU No. 2170818, IPC 8 ЕВВ 43/26, published in Bulletin No. 20 of 07/20/2001), which provides for the formation of hydraulic fractures in the formation with plantar water, while in the tubing and flexible pipes are lowered below them to the lower holes of the perforation interval for pumping proppant through them in a mixture with water-insulating cement in an amount sufficient to fill the lower part of the crack with the mixture to a level above the oil-water contact with filling part of the crack in the bottom water zone in the part of the crack below oil-saturated zone, while at the same time along the column of tubing (tubing) serves sand-carrier fluid with proppant in an amount sufficient to fill the upper part of the vertical crack. The disadvantages of this method are:

- firstly, hydraulic fracturing is carried out before waterproofing, which in carbonate rocks can lead to the formation of cracks in all power from the bottom water to the roof and there is no guarantee that during subsequent waterproofing of the bottom of the formation they can completely isolate (block the water supply channel into the productive part of the formation), which reduces the efficiency of hydraulic fracturing and causes rapid watering of the well during subsequent operation of the carbonate formation;

- secondly, after the formation of cracks in the formation by pumping a fracture fluid along the tubing string, a flexible pipe (GT) is lowered into the tubing string and a certain amount of time is spent on this operation during which the cracks partially close, then cement is waterproofed by a flexible pipe the bottom of the formation and the injection of sand-carrier fluid along the annular space between the tubing and GT columns to seal cracks that have already begun to close, which complicates the process of the method and reduces the permeability of formed cracks;

- thirdly, the tubing string must have a large diameter, since the annular space between the tubing string and the GT string is used for pumping the sand carrier, therefore, it is necessary to perform additional tripping operations to replace the tubing production string before hydraulic fracturing;

- fourthly, it is necessary to attract expensive equipment (sand mixer) and high-pressure pumping units for selling sand-carrier fluid with proppant to the formation.

The objectives of the invention are to simplify the process of hydraulic fracturing of a carbonate formation without involving expensive equipment and to exclude additional tripping operations to replace production tubing with a tubing string of a larger diameter, as well as increasing the efficiency of hydraulic fracturing in carbonate rocks by first waterproofing the bottom water and then fracturing of the productive part of the carbonate formation with the formation of highly permeable cracks in the carbo natnoy formation and with the possibility of eliminating watering wells during subsequent operation of the carbonate formation.

The problem is solved by the method of hydraulic fracturing of a carbonate formation, including the descent of the tubing string into the well - tubing with a packer and its subsequent landing, the descent of the tubing string - GT below the lower end of the tubing into the tubing string, injection of waterproofing cement through a flexible pipe, hydraulic fracturing carbonate formation with bottom water.

What is new is that the lower end of the GT is lowered to the level of water-oil contact - the oil-and-gas complex, the space between the tubing strings and the gas pipelines is sealed, the water-insulating cement is injected into the water-tight cement in the carbonate formation, and the well is filled from the bottom to the bottom-hole level, after which the space between with tubing and gas tubing columns and lifting the gas tubing column so that its lower end is 1-2 m below the carbonate formation roof, after which the total volume of the fracturing fluid is determined by the formula

V _g = k · h _p ,

where V _g is the volume of the fracture fluid, m ³ ;

k = 1.4-1.6 - conversion factor, m ³ / m;

h _p - the thickness of the productive part of the reservoir, m,

they seal the space between the tubing and GT columns and inject the first portion of the fracture liquid into the GT in the volume of 60-70% of the total volume - V _g under pressure not more than 25 MPa and at a speed of not more than 2 m ³ / min, after which the remaining volume of liquid the fracture is pumped into the GT in 3-5 cycles, alternating with the injection of a proppant, which is used as 25% hydrochloric inhibited acid, and the volume of acid is determined depending on the thickness of the productive part of the carbonate formation, based on the volume of 0.2 m ^{3 of} acid per 1 m of formation thickness n each injection cycle, after the last injection cycle performed prodavku acid aqueous surfactant in HT column volume, followed by aging 1-2 hours, then removed from the column HT tubing string and run into a well operation.

Figure 1 shows the process of waterproofing the bottom of the formation.

Figure 2 shows the process of hydraulic fracturing in the productive part of the carbonate formation: 1 - production well; 2 - tubing string (tubing); 3 - packer; 4 - bottomhole zone; 5 - carbonate formation; 5 '- the roof of the carbonate formation 5; 6 - a string of flexible pipes (GT); 7 - the lower end of the tubing string 2; 8 - annular space; 9 - the lower end of the column GT 7; 10 - level of KSS; 11 - face; 12 - cement pouring; 13 - intervals of perforation; 14 - cracks.

When operating carbonate formations, various types of treatment are used to increase oil inflow into wells: hydrochloric acid, thermoacid, foam acid, oil acid and others. Their experience has shown that with an increase in water cut of produced products to 20-50% or more, the efficiency of these well treatments decreases sharply and their implementation becomes unprofitable.

The essence of the proposed method consists in the fact that after isolation of the sole part of the formation by injection of hydraulic fracturing fluid in the carbonate formation, cracks are created, after which multiple alternate exposure of the fracturing fluid and the proppant is acid to the carbonate formation, and the fracturing fluid creates and expands (increases geometric dimensions) cracks, and the acid with each injection cycle of the gelled fracturing fluid penetrates deeper into the formation and there it reacts and dissolves the carbonate rock of the formation. Formation pressure plays a particularly important role in the Lower and Middle Carboniferous deposits, where there are no reliable clay formations that limit the growth of the crack height. The proximity of aquifers increases the risk of waterlogging after fracturing.

To carry out hydraulic fracturing using this method in the deposits of Tatarstan, carbonate formations of the Bashkir layer and the Vereisk horizon, as well as the Tournaisian layer with bottom water are suitable.

The proposed method of hydraulic fracturing of a carbonate formation is as follows.

When developing a deposit (not shown in Figs. 1 and 2), the producing well 1 (see Fig. 1) is equipped with production equipment, for example, a tubing string (2), a tubing string 73 mm in diameter, a packer 3 and an insert deep rod a pump (not shown in FIGS. 1 and 2). In the process of development, the flow rate decreases, while the products being produced are heavily flooded and the further work of this production well 1 becomes unprofitable. This is due to a decrease in the permeability of the bottom-hole zone 4 of the carbonate formation 5 and the breakthrough of plantar water into the production well 1.

In order to isolate water, intensify the flow and increase oil recovery, hydraulic fracturing of the carbonate reservoir is carried out.

A string of flexible pipes (HT) 6 is lowered into a tubing string 2 with a packer 3 located in the production well 1, for example, with a diameter of 45 mm below the lower end 7 of the tubing 2, while the packer 3 seals the annular space 8 of the producing well 1 during further technological operations. The lower end 9 of GT 6 is lowered to the level of the oil-water contact (OWC) 10, the space between the tubing strings 2 and GT 6 at the wellhead (not shown in FIGS. 1 and 2) of the producing well 1 is sealed (for example, using a preventer or lock); water-insulating cement along the GT 6 column in an amount sufficient to fill the space between the face 11 and the level of the KSS 10, to isolate the bottom water in the carbonate formation by filling the well from the bottom 11 to the level of the KSS 10, i.e. the flooded part of the carbonate formation 5, for example, the height of the bottom water (h _in ) in the carbonate formation 5 is 4 m, and including cement casting 12 of the well 1 from the bottom 11 to the level of KSS 10, for example 8 m

Water-insulating cement is injected, for example, using a cementing unit CA-320. Next, the space between the tubing strings 2 and GT 6 is depressurized at the mouth of the producing well 1 and the GT 6 string is lifted so that its lower end is 1-2 m below the roof of the 5 'carbonate formation 5.

The total volume of the fracturing fluid is determined by the formula:

where V _g is the volume of the fracture fluid, m ³ ;

k = 1.4-1.6 - conversion factor, m ³ / m;

h _p - the thickness of the productive part of the reservoir 5, m

Next, the space between the tubing strings 2 and GT 6 is sealed and the first portion of the fracturing fluid is pumped into GT 6 in a volume of 60-70% of the total volume - V _g under a pressure of not more than 25 MPa and at a speed of not more than 2 m ³ / min. The remaining volume of the fracture fluid is pumped through the GT 6 column (see FIG. 2) in 3-5 cycles, alternating with the injection of the proppant — 25% hydrochloric inhibited acid.

Pilot operations on hydraulic fracturing were carried out in carbonate formations with a thickness of the productive part equal to 10-30 m. The volume of the first portion of the fracturing fluid (technical name - buffer fluid) was from 20 to 80% of the total volume of the fracturing fluid. The fracture fluid was pumped under a pressure of not more than 25 MPa and at a speed of not more than 2 m ³ / min.

It was experimentally established that the greatest effect was obtained when the first portion of the fracturing fluid was injected - buffer fluid in a volume equal to 60-70% of the total volume of the fracturing fluid, at a pressure of not more than 25 MPa and a speed of not more than 2 m ³ / min, s subsequent injection of the remaining volume of the fracturing fluid into the HT in 3-5 cycles, alternating with the injection of a proppant, which was used 25% hydrochloric inhibited acid, and the volume of acid was determined depending on the thickness of the productive part of the carbonate formation, based on the volume 0.2 m ³ acid per 1 m of formation thickness for each injection cycle.

As a fracturing fluid, known compositions are used, for example, gel-like fracturing fluids developed by Khimekogang CJSC, having the trade names Himeko-N (TU2481-053-17197708), Himeko-T (TU2481-077-17197708-03), "Himeko-V" (TU 2499-038-17197708-98). The procedure for the preparation of gelled liquid and its injection using the pump unit CA-320 is described in patent RU No. 2358100, IPC 8 Е21В 43/26, publ. in bull. No. 16 dated 06/10/2009. As an additional example of the use of a gel-like fluid, there may be a structured hydrocarbon gel-like composition for hydraulic fracturing described in patent No. 2043491, IPC 8 Е21В 43/26, publ. September 10, 1995

According to the proposed method, the fracture fluid and the acid are injected, for example, using a cementing unit CA-320, while the space between the tubing strings 2 and GT 6 is sealed and the first portion of the fracture fluid is pumped into GT 6 in a volume equal to 60-70% of the total volume of the fracturing fluid under pressure not more than 25 MPa at a speed of not more than 2 m ³ / min

After that, the remaining volume of the fracture fluid is pumped through the GT 6 column (see FIG. 2) in 3-5 cycles, alternating with the injection of the proppant — 25% hydrochloric inhibited acid.

As a proppant, 25% hydrochloric inhibited acid is used, manufactured by the company NIINEFTEPROMHIM according to TU 2458-264-05765670-99 (Cheboksary, Russia), the injection volume of which is determined depending on the thickness (h _p ) of the productive part of the carbonate formation 5, based on the volume of 0.2 m ³ acid per 1 m of thickness of the formation for each injection cycle.

At the end of the last injection cycle, the acid in the GT column is sold with an aqueous solution of a surfactant, for example ML-81B according to TU 2481-007-48482528-99, at a concentration of 0.2%, i.e., for example 2 liters are added to 1 m ^{3 of} wastewater with a density ρ = 1100 kg / m ³ and in one volume of the GT 6 column, which is determined by calculation, depending on the size of the GT 6 column, followed by a technological exposure of 1-2 hours. At the end of the technological exposure GT 6 columns are removed from the tubing string 2, pumping equipment is lowered into the tubing string 2 udovanie (Figures 1 and 2 are not shown), as mentioned above insertion sucker rod pumps and trigger the production well 1 into operation.

Example 1

The thickness of the productive part of the carbonate formation 5 is h _p = 10 m. The value of the transfer coefficient is assumed to be equal to k = 1.5 m ³ / m.

Then, substituting into formula (1), we obtain the total volume of the fracture fluid:

V _g = k · h _p = (1.5 m ³ / m) · 10 m = 15 m ³ .

The volume of injected fluid rupture V _g = 15 m ³ .

When the thickness of the productive part of the carbonate formation 5 is equal to h _p = 10 m and the total volume of the fracture fluid is V _g = 15 m ³ , the injection volume of the first portion of the fracture fluid should not exceed 60% of the total injection volume. Therefore, V _g1 = 60% of the total volume - V _g will be V _g1 = (60% · 15 m ³ ) / 100% = 9 m ³ .

Due to the fact that cement 12 was made in the production well 1 from the bottom 11 to the level of BHK 10, the fracture fluid pumped through GT 6 in the volume of the first portion V _g1 = 9 m ³ through perforation intervals 13 (see Fig. 1) falls into the productive part of the carbonate formation 5 and forms cracks 14 (see figure 2).

After this, the remaining volume of the fracturing fluid: V _g0 = V _g -V _g1 = 15 m ³ -9 m ³ = 6 m ^{3 is} pumped through the GT 6 column (see Fig. 2) in three cycles, alternating with the proppant injection - 25 % hydrochloric inhibited acid.

For example, injection in three cycles, while in each of three cycles the remaining fluid volume is pumped to column HT 6 equal parts, namely: V _g0i = 6 m ^3/3 = 2 m ³ and based on the fact that the thickness of the productive parts (h _p ) carbonate formation 5 is 10 m, it turns out that the total volume of acid V _to = 10 m · 0.2 m ³ · 3 cycles = 6 m ³ . Then in each injection cycle: V _Ki = 6 m ^3/3 cycle = 2 m ^3.

Next, alternating the injection of the fracture fluid and the proppant, in three cycles the fracture fluid is _injected in a volume of V _r0i = 2 m ³ and the proppant V _ki = 2 m ³ . At the end of the last injection cycle, the acid in the GT column is sold with an aqueous solution of a surfactant, for example ML-81B according to TU 2481-007-48482528-99, at a concentration of 0.2%, i.e., for example , 2 liters are added to 1 m ^{3 of} waste water with a density ρ = 1100 kg / m ³ and in one volume of the GT 6 column, which is determined by calculation, depending on the size of the GT 6 column, followed by a technological exposure of 1 hour. At the end of the technological aging, the columns are removed GT 6 from the tubing string 2, pumping speed into the tubing string 2 Research (Figures 1 and 2 are not shown), as mentioned above insertion sucker rod pumps and trigger the production well 1 into operation.

Example 2

The thickness of the productive part of the carbonate formation 5 is h _p = 30 m. The value of the transfer coefficient is assumed to be equal to k = 1.5 m ³ / m.

Then, substituting into formula (1), we obtain the total volume of the fracture fluid:

V _g = k · h _p = (1.5 m ³ / m) · 30 m = 45 m ³ .

The volume of injected fluid rupture V _g = 45 m ³ .

When the thickness of the productive part of the carbonate formation 5 is equal to h _p = 30 m and the total volume of the fracture fluid is V _g = 45 m ³ , the injection volume of the first portion of the fracture fluid should not exceed 70% of the total injection volume. Therefore, V _g1 = 70% of the total volume - V _g will be V _g1 = (70% · 45 m ³ ) / 100% = 31.5 m ³ .

The fracture fluid and acid are injected, as described above, using the cementing unit CA-320, while the space between the tubing strings 2 and GT 6 is sealed and the first portion of the fracture fluid is injected into GT 6 under pressure not more than 25 MPa at a speed of not more 2 m ³ / min.

Due to the fact that cement 12 was made in the production well 1 from the bottom 11 to the level of BHK 10, the fracturing fluid pumped through GT 6 in the volume of the first portion V _g1 = 31.5 m ³ at intervals of perforation 13 (see Fig. 1) enters the productive part of the carbonate formation 5 and forms cracks 14 (see figure 2).

After this, the remaining volume of the fracturing fluid: V _g0 = V _g -V _g1 = 45 m ³ - 31.5 m ³ = 13.5 m ^{3 is} pumped through the GT 6 column (see Fig. 2) in four cycles, alternating with the injection proppant - 25% hydrochloric inhibited acid.

For example, each of the four cycles of the remaining volume of liquid is pumped into the column in HT 6 equal parts, namely: V = 13.5 m _g0i ^3/4 = 3.375 m ³ and based on the fact that the thickness of the productive part (h _n) carbonate formation 5 is 30 m, it turns out that the total volume of acid V _to = 30 m · 0.2 m ³ · 4 cycles = 24 m ³ . Then in each injection cycle: V _Ki = 24 m ^3/4 cycles = 6 m ^3.

Next, alternating the injection of the fracture fluid and the proppant, in four cycles the fracture fluid is _injected in a volume of V _r0i = 3.375 m ³ and the proppant V _ki = 6 m ³ . At the end of the last injection cycle, the acid in the GT column is sold with an aqueous solution of a surfactant, for example ML-81B according to TU 2481-007-48482528-99, at a concentration of 0.2%, i.e., for example 2 liters are added to 1 m ^{3 of} waste water with a density ρ = 1100 kg / m ³ and in one volume of the GT 6 column, which is determined by calculation, depending on the size of the GT 6 column, followed by a technological exposure of 2 hours. At the end of the technological aging, the columns are removed GT 6 from the tubing string 2, pumping speed into the tubing string 2 Research (Figures 1 and 2 are not shown), as mentioned above insertion sucker rod pumps and trigger the production well 1 into operation.

Example 3

The thickness of the productive part of the carbonate formation 5 is h _p = 20 m. The value of the transfer coefficient is assumed to be equal to k = 1.5 m ³ / m.

Then, substituting into formula (1), we obtain the total volume of the fracture fluid:

V _g = k · h _p = (1.5 m ³ / m) · 20 m = 30 m ³ .

The volume of injected fluid rupture V _g = 30 m ³ .

When the thickness of the productive part of the carbonate formation 5 is equal to h _p = 20 m and the total volume of the fracture fluid is V _g = 30 m ^3, the injection volume of the first portion of the fracture fluid should not exceed 65% of the total injection volume. Therefore, V _g1 = 65% of the total volume - V _g will be V _g1 = (65% · 30 m ³ ) / 100% = 19.5 m ³ .

The fracture fluid and acid are injected, as described above, using the cementing unit CA-320, while the space between the tubing strings 2 and GT 6 is sealed and the first portion of the fracture fluid is injected into GT 6 under pressure not more than 25 MPa at a speed of not more 2 m ³ / min.

Due to the fact that cement 12 was made in the production well 1 from the bottom 11 to the level of BHK 10, the fracture fluid pumped through GT 6 in the volume of the first portion V _g1 = 19.5 m ³ at intervals of perforation 13 (see Fig. 1) enters the productive part of the carbonate formation 5 and forms cracks 14 (see figure 2).

After this, the remaining volume of the fracturing fluid: V _g0 = V _g -V _g1 = 30 m ³ - 19.5 m ³ = 10.5 m ^{3 is} pumped through the GT 6 column (see Fig. 2) in five cycles, alternating with the injection proppant - 25% hydrochloric inhibited acid.

For example, each of the five cycles, the remaining volume of liquid is pumped into the column in HT 6 equal parts, namely: V = 10.5 m _g0i ^3/5 = 2.1 m ³ and, based on the fact that the thickness of the productive part ( h _p ) carbonate formation 5 is 20 m, it turns out that the total volume of acid V _k = 20 m · 0.2 m ³ · 5 cycles = 20 m ³ . Then in each injection cycle: V _Ki = 20 m ^3/5 cycles = 4 ^m3.

Then, alternating the injection of the fracturing fluid and the proppant, in five cycles the fracturing fluid is _injected in the volume V _g0i = 2.1 m ³ and the proppant V _ki = 4 m ³ . At the end of the last injection cycle, the acid in the GT column is sold with an aqueous solution of a surfactant, for example ML-81B according to TU 2481-007-48482528-99, at a concentration of 0.2%, i.e. for example, 2 liters are added to 1 m ^{3 of} wastewater with a density ρ = 1100 kg / m ³ and in the same volume of the GT 6 column, which is determined by calculation depending on the size of the GT 6 column with a subsequent technological exposure of 1.5 hours. At the end of the technological extracts extract GT 6 columns from the tubing string 2, pumping equipment is lowered into the tubing string 2 ore (not shown in FIGS. 1 and 2), as mentioned above, the plug-in sucker-rod deep pump and start production well 1 into operation.

The application of the proposed method in comparison with the prototype allows you to:

- firstly, the simple technological process of the method and low pressure - (up to 20 MPa) when conducting hydraulic fracturing in carbonate rocks can not attract expensive equipment (sand mixer) and high pressure pump units, while for the hydraulic fracturing process in carbonate rocks is sufficient one CAA-320 pump unit, in addition, additional tripping operations to replace operational tubing with a larger diameter tubing string are excluded. All this as a whole allows to reduce financial and material costs for hydraulic fracturing;

- secondly, to increase the efficiency of hydraulic fracturing in carbonate rocks by first waterproofing the bottom waters of the carbonate formation, and then by hydrofracturing the productive part of the carbonate formation with the formation of highly permeable cracks in the carbonate formation, which eliminates well flooding during subsequent operation of the carbonate formation.

Claims (1)

The method of hydraulic fracturing of a carbonate formation, including the descent into the well of a string of tubing — tubing with a packer and its subsequent landing, the descent of a string of flexible tubing — GT below the lower end of the tubing into the tubing string, pumping water-insulating cement through a flexible pipe, and carrying out hydraulic fracturing of the carbonate reservoir with plantar water, characterized in that the lower end of the GT is lowered to the level of the oil-water contact - the oil-water complex, the space between the tubing string and the GT is sealed, and the water-insulating cement is injected along the GT with insulation bottom water in a carbonate formation with a well being poured from the bottom to the bottom hole level, after which the space between the tubing and GT columns is depressurized and the GT column is lifted so that its lower end is 1-2 m below the roof of the carbonate formation, after which the total fluid volume is determined gap according to the formula:
V _g = k · h _p ,
where V _g is the volume of the fracture fluid, m ³ ;
k = 1.4-1.6 - conversion factor, m ³ / m;
h _p - the thickness of the productive part of the reservoir, m,
they seal the space between the tubing and GT columns and inject the first portion of the fracture liquid into the GT in the volume of 60-70% of the total volume - V _g under pressure not more than 25 MPa and at a speed of not more than 2 m ³ / min, after which the remaining volume of liquid the fracture is pumped into the GT in 3-5 cycles, alternating with the injection of a proppant, which is used as 25% hydrochloric inhibited acid, and the volume of acid is determined depending on the thickness of the productive part of the carbonate formation, based on the volume of 0.2 m ^{3 of} acid per 1 m of formation thickness n each injection cycle, after the last injection cycle performed prodavku acid aqueous surfactant in HT column volume, followed by aging 1-2 hours, then removed from the column HT tubing string and run into a well operation.

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