RU2847500C1 - Method for creating an artificial bottomhole zone in gas and gas condensate wells under conditions of cavitation in terrigenous formations - Google Patents

Abstract

FIELD: oil and gas production industry.

SUBSTANCE: the invention relates to the oil and gas industry, namely to a method for creating an artificial bottomhole zone in gas and gas condensate wells under conditions of cavitation in terrigenous formations, and can be used for the overhaul of gas and gas condensate wells. The method includes well killing, for which formation water or an aqueous solution of CaCl(₂₎ in a volume of at least four times the volume of the well, quartz sand, the amount of which is determined based on the analysis of field data obtained from previous repairs, Poliskrep-S composition at a rate of 120 litres per 1 tonne of quartz sand, then a killing line is installed with the possibility of preparing and injecting a water-sand slurry, using a mixer to prepare 0.2-0.5 m³ quartz sand is prepared using a mixer, for which Poliskrep-S is added to dry quartz sand and mixed until the quartz sand is completely wetted and a water-sand slurry is obtained. Formation water or an aqueous solution of CaCl(₂₎ is injected into the annular space in a volume not less than the volume of the wellbore, with simultaneous pressure relief from the pipe space, then the following is injected sequentially into the wellbore into the pipe space: 1-1.5 m³ of formation water or an aqueous solution of CaCl₂ , in a volume not less than the volume of the annular space of the pump-compressor pipes (PCP), water-sand slurry. During the injection process, the pressure in the pipe and annular spaces is monitored, at the end of the injection, the presence of circulation between the pipe and annular spaces is checked, then the injection of water-sand slurry is repeated, its injection is stopped when circulation between the pipe and annular spaces is achieved, and technological settling is carried out for at least 24 hours. After technological settling, check the circulation between the pipe and annular spaces. If there is no circulation, repeat the injection of water-sand slurry. If there is circulation, install a lifting unit, switch the well to a technological fluid for well repair, install a fountain tree, install blowout prevention equipment, lift the tubing, lower the drilling tools, break and lift the packer, if present, and remove the filter assembly. After removing the filter assembly, to eliminate absorption, repeat the injection of water-sand slurry treated with Poliskrep-S, followed by switching the well to a technological fluid for well repair and stopping work for 24 hours for technological settling. After technological settling, check the circulation between the pipe and annular spaces. If there is no circulation, repeat the injection of water-sand slurry. If there is circulation, remove the filter assembly, clean the wellbore and normalise the bottomhole conditions. geophysical surveys, tubing descent and well development.

EFFECT: acceleration of repair work, improvement of well maintainability.

7 dwg

Description

Field of technology to which the invention relates

The invention relates to the oil and gas production industry, namely, to a method for creating an artificial bottomhole formation zone in gas and gas condensate wells under conditions of cavern formation in terrigenous formations, and can be used for major repairs of gas and gas condensate wells.

State of the art

A known method for stabilizing the near-wellbore zone of a formation is by injecting a filler and a binding agent. Bituminous sand is injected into the near-wellbore zone as a filler, and tar sand is injected as a binding agent.

- diesel or oil alkaline waste and an aqueous solution of calcium chloride. The bituminous sand is pre-treated and pumped into the formation in a mixture with diesel or oil alkaline waste in a volume ratio of 1:3, respectively, after which a separation liquid is sequentially pumped - water in a volume of 0.25-0.5 ^m3 , a 10% aqueous solution of calcium chloride in a volume equal to the volume of alkaline waste, and a squeezing liquid - water in the volume of tubing, and the preliminary treatment of the bituminous sand is carried out by mixing the rock with diesel or oil alkaline waste, followed by draining and adding a 0.5-1% aqueous solution of calcium chloride, stirring the mixture for 2-3 minutes, after which the calcium chloride solution is drained and the rock is washed with water (see A.S. No. 1168700 dated 08/27/81, class E21B 33/13, published in OB N27, 1985).

The disadvantage of this method is the ineffectiveness of the fastening due to the low strength of the formed sand barrier and the reduction in the capacity and filtration characteristics of the bottomhole zone of the productive formation.

A method is known for lining the bottomhole zone of a productive formation, which includes perforating a casing string in a washed-out interval of the bottomhole zone, creating a sand permeable barrier by injecting quartz sand into the annular space through perforations in a carrier fluid with an aqueous solution of sodium silicate, followed by pumping an alcoholic solution of calcium chloride into the volume of the pore space of the created barrier, while, before creating the latter, an aqueous solution of sodium silicate is additionally injected, ρ = 1250-1300 kg/m ³ , in an amount ensuring complete filling of the pore annular space of the productive formation at a distance of 0.45-0.60 m from the well, and before pumping the alcoholic solution of calcium chloride - an emulsion solution of the following composition, wt. %:

Flotation reagent - oxal T-80 40-60 Neonol AF 9-12 0.10-0.15 Hydrocarbon liquid 39.85-59.90

in the volume of the pore space of the created sand permeable barrier, wherein liquid sodium glass with ρ=1400 kg/ ^m3 is used as an aqueous solution of sodium silicate, which is used to treat quartz sand before pumping it into the wellhead in a ratio of 0.20-0.30:1.00 parts by weight, respectively (see patent RU No. 2172811, IPC E21B 33/13, E21B 33/138, published on 27.08.2001, Bulletin No. 24).

The disadvantage of this method is the low efficiency of fastening, despite the creation of a permeable sand barrier while simultaneously maintaining the capacity and filtration characteristics of the bottomhole zone of the productive formation.

Known 1. A method for restoring a flooded gas or gas condensate well and preventing its flooding during further operation, characterized in that the well is killed, the sand plug is washed out and hydraulic fracturing of the formation is carried out with its simultaneous casing in the entire perforation interval, the volume of the bottomhole zone of the well in the perforation interval is divided into two production objects by pumping and pushing into the depth of the formation along the radius of a waterproofing composition that forms a waterproofing screen, the hardening time of the insulating composition is maintained, the volume of the well at the level of formation of the waterproofing screen is divided into two production zones by installing a packer lowered with a string of tubing - tubing, the tubing string is equipped with a gas lift valve in the upper part of the perforation interval of the upper object, the shoe of the string is installed below 1.5-2 m of the lower holes of the perforation interval of the lower object and water extraction by downhole gas lift from the lower production facility using gas energy from the upper production facility.

2. The method according to paragraph 1, wherein hydraulic fracturing and formation stabilization are carried out by pumping fracturing fluid containing an aqueous solution of medium-modulus liquid glass of the composition, mass %:

sodium silicate 12-17 acetone 4-7 methyl alcohol 10-18 water rest,

The fracturing fluid is injected into the formation 30-40 minutes after its preparation; when the hydraulic fracturing of the formation is achieved, proppant is additionally introduced into the fracturing fluid in the amount of 100-150 kg per ¹ m3 of fluid; after the fracturing fluid with proppant is injected into the formation, a water-alcohol solution of calcium chloride is injected with the composition, wt. %:

calcium chloride 17.0-19.0 ethyl alcohol 25.0-45.0 water rest

3. The method according to paragraph 1, wherein the waterproofing screen is created in the middle of the perforation interval with a thickness of 1.5-2 m to the depth of pressing the insulating composition into a layer with a radius of 5-7 m (see patent RU No. 2534291, IPC E21B 43/32, E21B 43/26, published 27.11.2014, Bulletin No. 33).

The disadvantage of this method is the insufficient productivity of wells, as well as an insufficiently long period between repairs.

The closest in technical essence and achieved positive effect and accepted by the authors as a prototype is:

1. A method for restoring the bottomhole formation zone of a gas well, which includes preparing a cement slurry that forms a gas-permeable stone after hardening, pumping it and forcing it through a tubing string (TU) with a squeezing fluid through perforations of the production string, killing the well, washing out excess cement slurry from the TU and the annular space of the TU, removing the cup from the production string to the lower boundary of the perforation interval, cleaning the sump, waiting for the cement slurry to harden, and developing the well, characterized in that an oil emulsion cement slurry (OEC) is prepared containing water and hydrocarbon liquid in a weight ratio of h., equal to 1:0.63-0.83, and a mass ratio of liquid and solid phase of 1.04-1.26, forming both a gas-permeable and water-resistant stone after hardening, additionally gas is withdrawn through the tubing string with a gradual increase in depression on the formation until the start of formation water removal, gas is pumped into the formation through the tubing string until a steady-state filtration mode is achieved, the well is stopped, the steady-state wellhead gas pressure in the tubing string and the annular space of the tubing is measured, the current wellhead gas pressure in the annular space of the tubing is continuously monitored during pumping and squeezing of the NTR through the tubing string, the value of the latter is compared from the moment of pumping a portion of the NTR, the volume of which is calculated using the formula

where V _pNTR is the volume of the NTR portion, ^m3 ;

Р _забдп - maximum permissible bottomhole pressure in the well, Pa;

S _HKT - area of the tubular space of the tubing, ^m2 ;

ρ _HTR – HTR density, kg/ ^m3 ;

q is the acceleration due to gravity, m/ ^s2 , or the volume of the entire prepared NTR and a portion of the squeezing liquid, the volume of which is calculated using the formula

where V _ппж is the volume of the portion of squeezing liquid, ^m3 ;

V _HTP – volume of all prepared HTP, ^m3 ;

ρ _пж - density of the squeezing liquid, kg/m ³ ,

with its maximum permissible value, preliminarily determined by the formula

where Р _узп is the maximum permissible wellhead pressure in the tubing annulus, Pa;

S _zp - area of the tubing annulus, ^m2 ;

V _HTP - current volume of injected HTP, ^m3 ;

V _пж is the current volume of pumped displacement fluid, ^m3 , and upon reaching the current value of the wellhead gas pressure in the annular space of the tubing its maximum permissible value, the gas is released from the annular space of the tubing at a rate calculated using the formula

where ΔP _узп (t) is the rate of gas bleed from the annular space of the tubing, Pa/s;

Q is the pump flow rate, ^m3 /s, until the end of pumping and pushing through the wellhead pressure, if the current value of the gas wellhead pressure in the tubing annulus does not reach its maximum permissible value, after the end of pushing through the wellhead pressure, process water is pumped into the tubing annulus with simultaneous monitoring of the wellhead pressure in the tubing string until the current value of the wellhead pressure in the tubing string reaches the value determined by the formula

where Р _уНКТ is the maximum permissible wellhead pressure in the tubing string when pumping displacement fluid into the annular space of the tubing, Pa;

L _NKT - tubing running depth, m;

h _NTR - the height of the NTR column left in the tubing string at the end of the NTR pushing, m,

and the well is killed after squeezing the NTR simultaneously with washing out excess NTR from the tubing string and the annular space of the tubing by pumping squeezing fluid into the tubing string with simultaneous regulation of the pressure in the tubing string by bleeding the gas-liquid mixture from the annular space of the tubing with the rate of growth of the wellhead pressure in the tubing string, determined by the formula

where ΔP _у нкт(t) is the rate of increase of the wellhead pressure in the tubing string, Pa/s, up to the value of the maximum permissible wellhead pressure in the tubing string at the moment of complete washout of the NTR from the tubing string, determined by the formula

R _uNKT1 = P _zabdop - ρпж⋅q⋅L _HKТ ,

where Р _уНКТ1 is the maximum permissible wellhead pressure in the tubing string at the moment of complete washing out of the NTR from the tubing string, Pa, and washing out of excess NTR from the annular space of the tubing is carried out at a constant achieved maximum permissible wellhead pressure in the tubing string, after which the cup is removed from the production string to the lower boundary of the perforation interval by washing out and the sump is cleaned.

2. The method according to paragraph 1, wherein an oil emulsion cement slurry of the following composition is preferably prepared, in parts by weight:

Oil well portland cement 100 Wood sawdust 5-8 Soda ash 3-10 Polyvinyl alcohol 0.8-0.9 Diesel fuel 44-56 Water - 59-82

(see patent RU No. 2183724, IPC E21B 33/13, published 20.06.2002, Bulletin No. 17).

The disadvantage of this method is that it does not guarantee the absence of absorption during repair work and does not eliminate complications during repairs.

Disclosure of invention

The objective of the proposed invention is to develop a method for creating an artificial bottomhole formation zone in gas and gas condensate wells under conditions of cavern formation in terrigenous formations, with minimization of the volume of liquid absorption into the productive formation during well killing and repair work, a reduction in the incidence of repeated absorption during repair work, the creation of a permeable sand massif in the cavern, having a strength exceeding the strength of the "mother" rock of the productive formation, the possibility of operating the well with an open face without installing filter assemblies, chemical neutrality of the created sand massif to contact interaction with natural gas, nitrogen, formation water, liquid hydrocarbons, acids and alkalis, which allows for chemical cleaning of the bottomhole zone of the productive formation for its decolmatation during further operation of the well.

The technical result that can be obtained with the help of the proposed invention is reduced to the acceleration and reduction of the cost of repair work, an increase in the maintainability of the well, which allows for trouble-free operation of the well, providing the required depression on the formation without destruction of the reservoir, to the creation in the cavern of the destroyed terrigenous reservoir of a permeable sand massif having a strength exceeding the strength of the "parent" rock of the productive formation.

The specified technical result is achieved using a method for creating an artificial bottomhole formation zone in gas and gas condensate wells under conditions of cavern formation in terrigenous formations, including killing the well, wherein to kill the well, formation water or a CaCl ₂ solution are first brought in in a volume of at least 4 well volumes, quartz sand, the amount of which is determined on the basis of an analysis of field data obtained from the results of previous repairs, a modified composition Poliskrep-S at the rate of 120 liters per 1 ton of quartz sand, then a killing line is installed with the possibility of preparing and pumping a water-sand pulp, using a concrete mixer, 0.2-0.5 m ³ of sand is prepared, for which a modified polymer composition "Polyskrep-S" is added to dry sand and mixed until the sand is completely wetted, formation water is pumped into the annulus in a volume of at least the volume of the well with simultaneous by releasing pressure from the tubular space, then the following is pumped into the well into the tubular space sequentially: 1-1.5 ^m3 of formation water, in a volume not less than the volume of the tubular space of the tubing pipes, water-sand slurry, during the pumping process, the pressure in the tubular and annular spaces is monitored, at the end of the pumping, the presence of circulation between the tubular and annular spaces is checked, then the pumping of sand slurry is repeated, its pumping is stopped when circulation is obtained between the tubular and annular spaces, when circulation is obtained, the pumping is stopped and a technological settling is carried out for at least 24 hours, after the technological settling, a check is made for circulation between the tubular and annular spaces, in the absence of circulation, the pumping of sand slurry is repeated, if there is circulation, a lifting unit is installed, the well is transferred to the process fluid for well repair, a Christmas tree is installed, blowout preventer equipment is installed, the tubing is lifted, Lowering the drilling tool, breaking and lifting the packer if present, removing the filter assembly, after removing the filter assembly, to eliminate absorption, repeat the pumping of sand slurry, followed by transferring the well to the process fluid for well repair and stopping work for a process standstill for 24 hours, then after the process standstill, check the circulation between the tubular and annular spaces, if there is no circulation, repeat the pumping of sand slurry, if there is circulation, remove the filter assembly, clean the wellbore, conduct geophysical surveys, lower the tubing and develop the well.

Brief description of drawings and other materials

Fig. 1 shows a method for creating an artificial bottomhole formation zone in gas and gas condensate wells under conditions of cavern formation in terrigenous formations, and the results of filtration studies.

Fig. 2 shows the same process flow diagram.

Fig. 3 - the same, a cavity.

Fig. 4 shows the same thing, pumping pulp.

Fig. 5 shows the same thing, drilling through the filter.

Fig. 6 - the same, normalization of slaughter.

Fig. 7 shows the same thing, lowering the pump and compressor pipes.

Implementation of the invention

During the operation of gas field wells and UGS facilities, caverns form in the near-wellbore zone due to the destruction of the productive formation and the removal of rock. This process occurs in wells whose productive formation is penetrated by open-face drilling, various types of perforation (e.g., cumulative, slotted, and bullet perforations), and various filter assemblies, as a result of erosive destruction. The volumes of the resulting caverns vary widely, from 1 to 60 cubic meters. The presence of caverns that are several times larger than the volume of the wellbore space within the productive formation interval (more than 2 ^m³ ) significantly complicates the wellbore killing process during repairs and is accompanied by large volumes of kill fluid absorption, increasing the costs and duration of repairs.

Experience with currently known methods shows that their use does not guarantee the absence of losses during repairs, requires repeated kill operations, does not eliminate repair complications, and has a negative impact on the reservoir. Furthermore, it's important to note the following important factor for ensuring the continued safe operation of wells: to ensure the operation of these wells, they must be equipped with filter assemblies, which is costly and reduces their maintainability.

Using a method for creating an artificial bottomhole formation zone in gas and gas condensate wells under cavernous conditions in terrigenous formations, the cavern is filled with a pre-treated (wetted with a special compound) granular material (sand, proppant). The chemical curing of the special compound results in a strong and permeable formation capable of withstanding variable gas and hydrodynamic loads during well operation without the installation of downhole filter assemblies. This method simultaneously solves two problems: reducing the volume of process fluid lost to the formation, thereby minimizing the negative impact on the bottomhole formation zone and reducing the time required for repair work, and creating a strong, permeable artificial bottomhole formation zone, allowing for open-hole well operation without the installation of a filter assembly, thereby reducing material consumption and, consequently, the duration of repair work. The result is achieved by using a special polymer composition for washing pre-treated granular material. This composition creates an indelible film on the granule surface. This film hardens after several hours, ensuring intergranular bonding of the granular material while maintaining open porosity within the created, washed massif within the existing cavern interval. The granulometric composition of sand or proppant is selected based on an analysis of the granulometric composition of the parent rock. D _(sand) = 5-6 d _{50 (parent rock)} . For example, d ₅₀ = 0.1 mm, and the diameter of sand (proppant) particles should be 0.5-0.6 mm. Industrially produced quartz sand of fraction 0.3-0.6 is applicable for this method. The polymer composition proposed is Poliskrep-S TU 2458-086-97457491-2013. Poliskrep-S is a two-component epoxy compound (resin + hardener) with viscosity and curing temperature regulators. The polymer consumption rate is 90-150 kg per ton of dry quartz sand or proppant. The consumption rate depends on the sand particle size. The finer the sand, the higher the polymer consumption rate. For a 0.3-0.6 mm particle size, the optimal consumption rate is 120 kg per ton of sand, and for a 0.4-0.8 mm particle size, the optimal consumption rate is 100 kg per ton.

The effectiveness of the proposed method is confirmed by experimental studies conducted on a filtration unit, Fig. 2, where:

1 - small crimping cylinder;

2 - tank with solution;

3 - core holder;

4 - gas meter.

Under laboratory conditions at room temperature, pre-treated sand is washed in batches to create an artificial formation. Washed quartz sand of 0.3-0.6 mm fraction (GOST R 51641-2000) is used for the experiment, wetted with a modified "Polyskrep-S" compound. An aqueous calcium chloride solution with a density of 1050 kg/ ^m³ is used for washing. The washing process is carried out in batches by squeezing the sand pulp with an aqueous _CaCl² solution at a pressure of 0.05-0.1 MPa. During squeezing, the sand is deposited on a filter, creating a layer 100-130 mm thick. After the sand is completely washed, it is left to cure in a _CaCl2 solution. After 24 hours, the strength of the sand is tested. It is not eroded by the flow of the aqueous _CaCl2 solution, but exhibits plastic deformation under pressure, indicating the beginning of the curing of the modified Poliskrep-S compound. The sample is left to cure for 3 days. After 3 days, the sand has gained strength and is not subject to deformation under external influences, indicating the complete curing of the modified Poliskrep-S compound. The sample is removed from the filtration unit for testing of its filtration and strength properties.

To obtain information on the optimal amount of sand wetting material, three samples were obtained during the experiment at different consumption rates of the modified “Polyskrep-S” composition per 1 kg of sand: 1-90 ml/kg; 2-120 ml/kg; 3-150 ml/kg.

To study the filtration and strength properties of the obtained samples of the washed massif, cylindrical specimens with a diameter of 30 mm and a length of 50 mm were cut. Gas permeability measurements were taken using the setup: 1 - 3155 mD; 2 - 3078 mD; 3 - 1331 mD.

Determination of adhesion of monolithic specimens was carried out by loading with spherical indenters in accordance with the recommendations. To determine the bulk strength indicators, the specimens are subjected to splitting by compression with a pair of spherical indenters in an ISM-190 Viking testing device in accordance with GOST 24941-81. Based on the results, the following are determined: the destructive load (N) and the surface area of the through rupture of the specimen (m2⋅10 ^-6 ). Then, the values of the Ultimate compressive strength are obtained by calculation: 1 - 12.59 N/m ² ⋅10 ⁶ ; 2 - 14.26 N/m ² ⋅10 ⁶ ; 3-20.81 N/m ² ⋅10 ⁶ . Based on a comparison of the available data on the compressive strength of rocks in the productive formation of underground gas storage facilities in operation, where the destruction of the productive formation is noted during operation: - Uvyazovskoye UGS - 1.93 N/m ² ⋅10 ⁶ , - Kasimovskoye UGS - 2.1 N/m ² ⋅10 ⁶ , - Nevskoye UGS - 3.03 N/m ² ⋅10 ⁶ , - Severo-Stavropolskoye UGS - 6.43 N/m ² ⋅10 ⁶ The following can be concluded: the sand massif created as a result of influx into the cavern has a strength exceeding the strength of the "parent" rock of the productive formation, while the permeability of the artificial bottomhole zone is equal to or exceeds the permeability of the "parent" rock. Analysis of the obtained results shows that the sand mass created as a result of washing into the cavern makes it possible to operate open-face wells without installing filter assemblies.

An example of a specific implementation of the method for creating an artificial bottomhole formation zone in gas and gas condensate wells under conditions of cavern formation in terrigenous formations.

The well being treated has the following design:

- a conductor with a diameter of 324 mm was lowered to a depth of 250 m and cemented to the mouth;

- a technical column with a diameter of 245 mm was lowered to a depth of 600 m and cemented to the wellhead;

- a production casing with a diameter of 168 mm was lowered to a depth of 860 m and cemented to the wellhead.

The perforation interval of the production casing is 840-850 m. A gravel pack screen is installed in the well. The packer is set at a depth of 830 m and lowered using 89 mm diameter tubing. During operation, the integrity of the downhole screen is compromised, and the well produces sand during operation due to reservoir failure, forming a cavern. The volume of formation failure can vary from 2 to 80 ^m³ (Fig. 3). Repair work is complicated by abnormal pressure drop (APF) conditions and significant losses of kill fluid. Repair and restoration work involves preliminary infilling of the resulting cavern with sand slurry until circulation is established. The technology for well killing and retrieval of existing downhole equipment is standard. The difference is the preparation of sand for filling the cavern. For this purpose, washed quartz sand of 0.3-0.6 mm fraction is used, which is then wetted dry with a modified Poliskrep-S compound at a ratio of 120 liters per 1 ton of sand in a 1.0 ^m³ concrete mixer. The prepared, wetted sand is pumped into the formation as a slurry through an ejector funnel. An aqueous solution of calcium chloride with a density of 1050 kg/ ^m³ or formation water is used as the carrier fluid.

The order of operations is as follows:

1. Sand slurry is pumped into the wellbore until circulation is achieved, i.e., until the near-wellbore zone of the formation is filled with sand and the holes in the filter are blocked. Filling of the cavity is determined by restoring circulation of the killing fluid (Fig. 4).

2. Once circulation is established, blowout prevention equipment is installed, the tubing is disconnected from the packer assembly, and the tubing is pulled out. During this operation, the hydrodynamic action of the process fluid column may open the backfilled holes in the filter, resuming lost circulation. In this situation, treated sand slurry is injected until the lost circulation is eliminated.

3. Lower the mating part of the disconnector onto the drill pipe to release the packer. The packer is released and retrieved.

4. Using the drilling assembly, the filter assembly is drilled and then lifted (Fig. 5).

5. The created artificial formation, after its aggradation and due to the chemical curing reaction of the Poliskrep-S composition, gains strength to 0.5-0.8 MPa within 10-14 hours. Further strength gains occur within 30 days, reaching 8.0 MPa. After 10-14 hours of exposure of the sand, wetted with the composition, to an aqueous environment, the formation is resistant to the hydrodynamic effects of liquids, does not erode, and has open porosity. This reduces the likelihood of repeated absorption, and accordingly, the volume of liquid entering the formation is reduced. As a result, an erosion-resistant artificial formation with permeability exceeding that of the parent rock is formed in the near-wellbore zone at the site of the cavern.

6. Then, an assembly is lowered into the well to drill out the artificial filter and normalize the bottomhole (Fig. 6).

7. Based on the decision of the geological service, a decision is made to install a downhole filter and the technological assembly of the tubing is lowered for well operation (Fig. 7).

8. The well is put into operation.

Sand filled with Poliskrep-S has a strength higher than that of the parent rock, which, while maintaining permeability, eliminates the need for a filter assembly with a packer. This method speeds up and reduces the cost of repairs, improves well maintainability, and allows for trouble-free well operation, ensuring the required drawdown on the formation without damaging the reservoir.

The applied composition Poliskrep-S is not washed off from the surface of the treated sand by process liquids and formation fluids, has a slow reaction time, the onset of hardening is after 3-4 hours in an aqueous environment at a temperature of 20-25°C, with a slow gain in strength after 14-14 hours.

The proposed invention, in comparison with the prototype and other known technical solutions, has the following advantages:

- reduction of the volume of process fluid absorption into the formation;

- minimization of the negative impact on the bottomhole formation zone;

- reduction of time required for repair work;

- creation of a strong, permeable artificial bottomhole formation zone, allowing for open-hole well operation without installing a filter assembly;

- reduction of material consumption;

- reduction in the duration of repair work.

Bibliography

1. Pyatakhin M.V. “Geomechanical problems in well operation.” - M.: Gazprom VNIIGAZ, 2012. - 266 p. Korshunov V.A., Kartashov Yu.M.

2. “Determination of bulk strength indicators of rock samples when loaded with spherical indenters” // VNIMI. - 2001.

3. GOST 24941-81.

4. A.S. No. 1168700 of 08/27/81, class E21B 33/13, published in OB No. 27, 1985.

5. Patent RU No. 2172811, IPC E21B 33/13, E21B 33/138, published 08/27/2001, Bulletin No. 24.

6. Patent RU No. 2534291, IPC E21B 43/32, E21B 43/26, published 27.11.2014, Bulletin No. 33.

7. Patent RU No. 2183724, IPC E21B 33/13, published June 20, 2002, Bulletin No. 17.

8. TU 2458-086-97457491-2013.

9. GOST R 51641-2000.

Claims (1)

A method for creating an artificial bottomhole formation zone in gas and gas condensate wells under cavern formation conditions in terrigenous formations, including killing the well, characterized in that for killing the well, formation water or an aqueous solution of CaCl ₂ are first brought in in a volume of at least four well volumes, quartz sand, the amount of which is determined on the basis of an analysis of field data obtained from the results of previous repairs, the Poliskrep-S composition at the rate of 120 liters per 1 ton of quartz sand, then a killing line is installed with the possibility of preparing and pumping a water-sand pulp, using a mixer, 0.2-0.5 m ³ of quartz sand are prepared, for which the Poliskrep-S composition is added to dry quartz sand and mixed until the quartz sand is completely wetted and a water-sand pulp is obtained, formation water or an aqueous solution of CaCl ₂ is pumped into the annulus in a volume of at least wells with simultaneous bleeding of pressure from the tubing space, then the following are pumped sequentially into the well into the tubing space: 1-1.5 ^m3 of formation water or an aqueous solution of _CaCl2 , in a volume not less than the volume of the tubing space of the tubing, water-sand pulp, during the pumping process, the pressure in the tubing and annular spaces is monitored, at the end of the pumping, the presence of circulation between the tubing and annular spaces is checked, then the pumping of the water-sand pulp is repeated, its pumping is stopped when circulation is obtained between the tubing and annular spaces and a technological settling is carried out for at least 24 hours, after the technological settling, a check is made for circulation between the tubing and annular spaces, in the absence of circulation, the pumping of the water-sand pulp is repeated, if there is circulation, a lifting unit is installed, the well is transferred to the process fluid for repairing the well, installation Festoon tree, installation of blowout prevention equipment, raising of tubing, lowering of drilling tool, breaking and raising of packer if present, extraction of filter assembly, after extraction of filter assembly to eliminate absorption, repeat injection of water-sand slurry treated with Poliskrep-S composition, followed by transfer of well to process fluid for well repair and stopping of works for process settling for 24 hours, then after process settling, check of circulation between tubing and annulus is carried out, if there is no circulation, injection of water-sand slurry is repeated, if there is circulation, extraction of filter assembly is carried out, wellbore cleaning and normalization of bottomhole, geophysical surveys, lowering of tubing and development of well.