EA040038B1 - METHOD FOR MULTIVATION OF OIL AND GAS WELLS - Google Patents

Description

The invention relates to the oil industry, and in particular to the technology of killing oil and gas wells.

Killing is understood as a set of successive technological operations aimed at temporarily stopping the flow of fluids from the formation into the well by creating back pressure on the formation with technological compositions.

Currently, a significant part of oil and gas fields is at the stage of declining production or the final stage of development. Natural wear and tear of well structures and underground equipment leads to a reduction in overhaul periods, an increase in unscheduled well workovers and the introduction of a large number of geological and technical measures, which require the involvement of maintenance and workover teams to kill wells.

According to the current requirements for labor protection and safety during repair work on oil and gas wells, wells with reservoir pressure above hydrostatic pressure and wells with reservoir pressure below hydrostatic pressure, but in which, according to calculations, the conditions of flowing or oil and gas shows, are subject to killing.

Experience shows that in many cases, after killing a well with the use of water-based process fluids, there is a deterioration in the porosity and permeability parameters of the bottomhole formation zone (BFZ), which in turn has a negative impact on the efficiency of well operation.

The main reasons for the deterioration of the porosity and permeability parameters of the bottomhole zone are: swelling of the clay components of reservoir rocks as a result of hydration;

the blocking action of water, due to capillary and surface phenomena occurring in the pore space as a result of the mutual displacement of immiscible liquids;

the formation of insoluble sediments in the pore space as a result of the interaction of filtrates and formation fluids;

clogging of pores with solid particles that have penetrated into the formation along with the filtrate;

clogging of pores by precipitation of highly mineralized aqueous solutions as a result of precipitation of salts in pore channels in crystalline form;

decrease in the phase permeability of the bottomhole zone for oil as a result of the impact of aqueous solutions on the surface of the rocks.

The degree of manifestation of these processes depends on many factors that affect the reservoir system, including the geological-physical and lithofacies conditions of the reservoir, the physicochemical properties of reservoir fluids, the well operation mode, as well as the technological conditions of well killing.

Hydrophilization of the surface of the pore channels, the formation of insoluble sediments and the swelling of clay particles contained in the bottomhole zone are among the main factors that have a negative impact on the porosity and porosity parameters of the bottomhole zone as a result of well killing.

To prevent the negative impact of aqueous solutions on the formation system of the BHZ during well killing, it is necessary to use active technological compositions in the form of buffer packs, which ensure the preservation or improvement of the reservoir properties of the BHP and reduce the phase permeability of rocks to water.

Active compounds used as buffer packs prevent the interaction of aqueous salt solutions with the formation system of the BFZ. The ability of active compositions to hydrophobize the surface of rocks ensures a decrease in water cut in well production and a reduction in the duration of technological operations for the development and bringing the well to the technological regime.

From US patent 2016/0017204 (IPC SO9K 8/36, SO9K 8/42, SO9K 8/584, SO9K 8/60, E21B 43/16, published 01/21/2016), a method for preparing an emulsion for treating oil and gas wells is known. The emulsion contains oil, many hydrophobic silicon dioxide nanoparticles, an aqueous salt solution. The disadvantage of this method is that the emulsion may contain an aqueous phase in the range from 1 to 95% vol. when the content of the aqueous phase is more than 85 vol.%, the emulsion is characterized by high dynamic viscosity and increased ultimate shear stress. The increased viscosity characteristics of the emulsion lead to the failure of pumping units during injection and emergency situations associated with exceeding the permissible injection pressure on the production line. Also, a decrease in the volumetric water content in the emulsion below 65 vol.% will lead to separation of the emulsion into its constituent phases, i.e. loss of system stability and loss of technological properties.

From US patent 2017/088762 A1 (IPC S09K 8/05, SO9K 8/42, SO9K 8/57, E21B 21/00, E21B 33/13, published 03/30/2017) a method for preparing a water-based salt solution containing nanoparticles silicon dioxide. The method is aimed at reducing the crystallization temperature of salts in high-density aqueous solutions, which are used in the drilling and completion of oil and gas wells. The disadvantage of this method is that the use of water-based salt solutions with high density during the initial opening of oil and gas reservoirs negatively affects the phase

- 1 040038 reservoir permeability for oil and gas. The method does not provide for preventing the contact of water-based technological compositions with an oil-and-gas-saturated porous medium.

From the patent WO 2016/196332 A1 (IPC SO9K 8/05, SO9K 8/48, SO9K 8/504, published 12/08/2016) a method for preparing a water-based salt solution containing nanoparticles of various minerals is known. The method is aimed at reducing the crystallization temperature of salts in high-density aqueous solutions, which are used in the drilling and completion of oil and gas wells. The method involves the use of a high-density aqueous solution containing nanoparticles of various minerals as the internal phase of the emulsion. The disadvantage of this method is that the use of a high-density water component in the emulsion will lead to an increase in the density of the emulsion, which is a negative factor when passing absorption intervals during drilling and well completion, because leads to the absorption of the emulsion by the receiving intervals and loss of control of the drilling process.

From a.s. USSR No. 1629501 (MPK E21V 43/12, SO9K 7/06, published on 02/23/1991) a well killing method is known. The method involves successive injection of three compositions into the bottomhole formation zone - an aqueous solution of a surfactant, an invert emulsion and a kill fluid. The disadvantage of the method is that the method does not provide for preventing the interaction of water-based solutions with the reservoir system. When an aqueous solution is injected into the bottomhole formation zone, despite the presence of surfactants in its composition, the phase interacting with the oil and gas saturated porous medium will be water. In this regard, the subsequent injection of an invert emulsion pack will not perform the function of an active pack, but will only limit the penetration of the next pack of an aqueous solution into the bottomhole formation zone.

From the patent of the Russian Federation No. 2348799 (MPK E21V 43/12, SO9K 8/42, published on March 10, 2009), a method of killing gas wells is known, including sequential injection of three compositions into the bottomhole formation zone - killing fluid, blocking fluid and displacement fluid. In this case, diesel fuel or condensate, an emulsifier, chalk with asbestos, and an aqueous solution of calcium chloride are used as blocking fluid. The disadvantage of this method is that after killing the well with a composition with chalk, asbestos and carboxymethyl cellulose, it is necessary to carry out an additional geological and technical measure - acid treatment, which is aimed at cleaning the bottomhole formation zone from chalk and asbestos.

From the patent of the Russian Federation No. 2184839 (MPK E21B 43/12, published 07/10/2002) a method for preparing a composition for killing wells is known. The composition contains diesel fuel or oil, an emulsifier, hydrophobic chemically modified silica and an aqueous solution of calcium chloride or potassium chloride. The disadvantage of this method is that the addition of chemically modified silica does not change the phase permeability of the surface of the pore channels, but only increases the stability of the emulsion-suspension system.

From the patent of the Russian Federation No. 2357997 (MPK S09K 8/42, published on 06/10/2009) a method for preparing a blocking fluid for killing wells is known. The blocking fluid contains diesel fuel or oil, an emulsifier, organophilic clay, an aqueous solution of calcium chloride or potassium chloride, a filtration regulator, and an ABR water repellent. The disadvantage of this method is the presence in the composition of particles of organophilic clay and chalk, tk. these solid particles are completely insoluble in water or hydrocarbons and will clog the pore channels, reducing the permeability of the rocks.

From patent WO2017058492 (IPC SO9K 8/36, published on 04/06/2017) a method for preparing a composition for killing wells is known. The composition contains diesel fuel or oil, solid particles of hydrophobic colloidal silicon dioxide, organophilic clay, bentonite or other clay particles and saline. The disadvantage of this method is the presence in the composition of solid particles of organophilic clay, bentonite, which reduce the permeability of rocks in the bottomhole formation zone and adversely affect the phase permeability of rocks for oil.

From the patent of the Russian Federation No. 2279462 (MPK SO9K 8/42, published on 07/10/2006), a method for preparing a composition for killing wells containing hydrocarbons, an emulsifier, a polymer emulsion, highly dispersed hydrophobic materials of silicon oxides and an aqueous solution of calcium chloride or potassium chloride is known. The disadvantage of this method is the presence in the composition of the polymer emulsion (up to 5 vol.%), which does not dissolve in reservoir conditions and is a synthetic colmatant of the porous medium.

To solve these problems in the development of oil and gas fields, a method for killing oil and gas wells is proposed, based on the sequential injection of an emulsion system (ES) into the bottom hole zone containing a colloidal solution of hydrophobic nanoparticles of silicon dioxide and an aqueous solution of calcium chloride or potassium chloride containing a water repellent 1-2 about.%.

The essence of the invention lies in the fact that the method of killing oil and gas wells includes the sequential injection of an active pack and displacement fluid into the bottomhole formation zone, while an emulsion system is used as an active pack, containing (vol.%): diesel fuel or prepared oil from the point preparation and pumping of oil - 15-30, emulsifier - 2 040038

2-3, a colloidal solution of hydrophobic silicon dioxide nanoparticles - 0.5-1 and an aqueous solution of calcium chloride or potassium chloride - the rest, and an aqueous solution of calcium chloride or potassium chloride with the addition of a water repellent brand IVV-1 or CHAS- M 1-2 vol.%. In this case, the colloidal solution of hydrophobic silicon dioxide nanoparticles may contain, vol.%: amorphous silicon dioxide - 30-32.5, propylene glycol monomethyl ether - 67-69, water - the rest. As an emulsifier, a composition of the following composition (vol.%) can be used: esters of higher unsaturated fatty acids (linoleic, oleic, linolenic) and resin acids - 40-42, amine oxide - 0.7-1, high-molecular organic heat stabilizer - 0, 5-1, diesel fuel (summer or winter) - the rest. At the same time, a suspension of lime or bentonite in diesel fuel (vol.%) is used as a high-molecular organic heat stabilizer: diesel fuel - 45, lime or bentonite - 55%.

Hydrophobizator IVV-1 is produced according to TU 2482-111-56856807-2016 and is a mixture of alkyldimethylbenzylamonium chloride and quaternary ammonium salt of a tertiary amine, obtained by condensation of alkyldimethylamine and benzyl chloride.

Hydrophobizator CHAS-M is produced according to TU 20.41.20-125-56856807-2017 and is a water-alcohol solution of quaternary ammonium salts of alkyldimethylamine.

The technical result of the invention is to increase the efficiency of geological and technical measures for killing oil and gas wells, high thermal stability and aggregation stability of the emulsion system for killing wells, as well as the ability to control the surface-active properties and viscosity of the emulsion system depending on the porosity and geological and physical characteristics of the bottom hole reservoir zones.

The invention is illustrated by the following graphics.

In FIG. 1 is a table showing the technique and equipment for the preparation and injection of an active pack.

In FIG. 2 shows a table illustrating the results of measuring the density of ES with a density of the water component of 1200 kg/m ³ .

In FIG. 3 shows a table illustrating the results of measuring the density of ES with a density of the water component of 1100 kg/m ³ .

In FIG. 4 shows a table illustrating the results of measurements of the aggregative stability (electrical stability) of ES with a density of the water component of 1200 kg/m ³ .

In FIG. 5 shows a table illustrating the results of measurements of the kinematic viscosity of ES with a density of the water component of 1200 kg/m ³ .

The use of ES containing a colloidal solution of hydrophobic silicon dioxide nanoparticles as an active pack eliminates the negative factors that may be caused by the traditional method of well killing with aqueous solutions.

The ES proposed in the invention in the form of an active pack (AP) prevents the interaction of the water-based kill fluid with the BHP formation system during well killing. When ES is filtered into the pore channels and cracks in the BFZ, they are hydrophobized, which leads to a decrease in the rate of rock impregnation with water-based process fluids during killing, as well as during the development, putting into operation and operation of the well.

The content of a colloidal solution of hydrophobic nanoparticles of silicon dioxide in the ES provides: the ability to control the rheological properties of the ES in a wide range by changing the volume content of the colloidal solution of nanoparticles in the system;

twofold increase in ES stability;

change in the contact angle of selective wettability of rocks, achieved due to the surface activity of nanoparticles.

When an ES moves in a porous medium, its effective viscosity depends on the volumetric water content in the system and the rate of its filtration in the porous medium, increasing with an increase in the volumetric water content and a decrease in the filtration rate. This leads to the fact that when the ES moves in a porous medium, self-regulation of the viscosity properties, speed and direction of filtration into the depth of the bottomhole zone occurs. These physical properties of ES make it possible to form a solid screen in the BFZ, which preferentially penetrates into the most permeable working intervals of the BFZ.

The invention provides an increase in the efficiency of geological and technical measures for killing oil and gas wells.

Preparation of the active pack

Preparation of AP is carried out at the solution preparation unit: BPR solution preparation unit (mixer with stirrer and external centrifugal pump). The necessary equipment for preparing and pumping the active pack into the well is presented in the table in Fig. 1.

Diesel fuel or prepared oil from the point of preparation and pumping of oil - 15-30 vol.% is collected into the tank for the preparation of AP. Next, a centrifugal pump is started for circulation and a paddle mixer. After that, the emulsifier - 2-3 vol.%, the colloidal solution of silicon dioxide nanoparticles - 0.5-1 vol.% and the aqueous solution of calcium chloride or potassium chloride - the rest are dispersed successively in diesel fuel.

As an emulsifier, a composition of the following composition (vol.%) can be used: esters of higher unsaturated fatty acids (linoleic, oleic, linolenic) and resin acids - 40-42, amine oxide - 0.7-1, high-molecular organic heat stabilizer - 0, 5-1, diesel fuel (summer or winter) - the rest.

As a colloidal solution of hydrophobic silicon dioxide nanoparticles, a composition can be used containing, vol.%: amorphous silicon dioxide - 30-32.5, propylene glycol monomethyl ether - 67-69, water - the rest.

AP components are introduced into the hydrocarbon base through an ejector using a vacuum hose.

Technological tanks must be equipped with paddle mixers that ensure a constant and uniform distribution of reagents throughout the volume. To ensure obtaining and maintaining stable properties of AP, it is recommended to use paddle mixers with a reverse direction of rotation.

The quality of preparation and the stability of the properties of AP depends on the completeness of mixing coverage of the entire volume of the preparation container, the cleanliness of the containers, the rate of introduction of the components and the dispersion time. It is recommended to use a container with bevelled corners (shape close to cylindrical).

Quality control of AP preparation

The control is carried out by checking the sedimentation stability of the AP. The test is considered positive if, when the AP is kept at room temperature for 2 hours, the separation of the aqueous phase does not exceed 2% of the total ES volume.

Calculation of the active pack volume

The volume of AP (V), m ³ is determined by the volumes of the opened perforation interval, well sump and safety margin, according to the formula:

V= (h _T3 - h _Bg + h _3an ) * Uud + 0.0007 * hen + Supplements, M ³ (1) where h _tz is the level of the current face, m;

h _вg - the level of the upper mark of the perforation interval, m;

h _for π - safe margin level, m (with a production string with a depth of less than 500 m -25 m);

V _beats - specific internal volume of the casing string, m ³ per 1 p. meter;

0.0007 - AP consumption coefficient for wetting the pipe walls;

h _сn - depth of descent of the tubing string (tubing);

V _nrogavkU - volume of AP injection into the reservoir, m ³ .

The volume of AP injection into the reservoir V _n p _OgаkU is determined by the formula:

Refills = 1/Ka + 0.2*(h _BCK p) ^1/2 , M ³ , (2) where h _vskr - opened perforation interval, m

Ka is an anomaly coefficient, where Ka = Рformation/Рhydrostatic, where Рformation is formation pressure, Рhydrostatic is hydrostatic pressure.

Criteria for calculating the level of safe margin h _{for n} - the upper limit of the AP installation (with a production string with a depth of more than 500 m).

In the presence of a suspension of an electric centrifugal pump (ESP), the AP is installed from the bottom to an interval located 50 m above the upper perforation holes, but 50 m below the pump intake:

h-(h _e d+50 M)-btek.zab , (3) where h _vg - the level of the upper perforations, m;

h _t e _k . _zab . - level of the current slaughter, m.

In the presence of a packer device, the AP is set from the current bottomhole to the interval of setting the packer:

h (hnaK.~hmeK.3a6) , (4) where As is the installation level of the packer device, m;

h _t e _k . _zab . - level of the current slaughter, m.

When using coiled tubing (CT) with a packer device, the AP is set from the current bottomhole to the interval of setting the packer similarly to formula 4.

When using coiled tubing without a packer, the AP is installed from the bottom to the interval located 50 m above the upper perforation holes:

h (hi.) 50 m) - tek.zab. , (5) where h _вg - the level of the upper perforation holes, m;

h _t e _k . _zab . - level of the current slaughter, m.

The excess volume of AP for wetting the walls is determined based on the minimum norm of 1 m ³ per

- 4 040038 well, the estimated consumption of AP for wetting is 0.7 dm ³ /1 m of lowered pipes. The upper boundary of the AP installation must be at least 50 m below the intake of the lowered downhole pumping equipment (DPU) to ensure circulation when the well is balanced during the killing process.

Installing an active pack

The installation of AP is carried out by standard methods: direct injection or reverse injection, depending on the availability, type of underground well equipment and design features of the well. The annulus re-injection method is preferred.

It is not recommended to kill by direct injection in the presence of a deflated electric centrifugal pump (ENP) or a sucker rod pump (SHP) due to the risk of breaking the column with an increase in pressure when the AP is squeezed through the hole of the knockdown valve.

If there is a leakage in the production string, a possible way to install the AP is the direct injection method with a maximum allowable pressure limit of 35 atm on the tubing string with downhole pumping equipment (DPP).

The emulsion system with these components is not intended for killing wells with leaks in the production string.

Installation of AP by direct download.

1) The volume of AP is less than the volume of tubing.

The first stage is the injection of AP into the tubing, finishing to the bottom of the tubing (pump hanger) in circulation with an open annular valve.

AP is pumped into the tubing in the volume of the void space of the tubing and moved to the bottom of the tubing (funnel cut) with the killing fluid for circulation in the volume:

Y (circ.) ^\u003d Y (tubing) - V (rods) ^- V (AP) (6) where Y ( _circus ) - the volume of killing fluid pumped with an open annular valve to move the AP to the bottom of the tubing, m ³ ;

V( _HKT ) - internal volume of tubing, m ³ ;

V( _rod ) - displacement of rods, m ³ ; (with ESP Y( _rods ) = 0);

V( _AP ) - AP volume, m ³ .

The second stage is the squeezing of the AP to the bottomhole with the annular valve closed with the killing fluid in the volume:

U(prod.) 0.00 I^Vk (str.p(11(current zab.) ^- h(HKT)) - V (ApG 1 U(well under GNO) - V (AP)X 1 (7 ) where V( _pr o _d ) - the volume of killing fluid pumped with the annular valve closed (for pushing), m ³ ;

0.001 - conversion factor dm ³ (l) to m ³ ;

U _to .( _ud ) - specific internal volume of the casing string under GNO, dm ³ /m,

b( _NK t) - pump or tubing suspension depth, m;

b( _te k. _zab .) - depth of the current face, m;

V (A _P ) - the volume of AP, m ³ ;

U ( _well . _{under GNO} ) - the volume of the well under GNO, m ³ ;

- reserve volume of killing fluid for squeezing AP into the reservoir, m ³ .

) The volume of the AP is greater than the volume of the tubing.

The first stage is the injection of AP into the tubing in the volume of the void space of the tubing (before the pump hanger) for circulation with an open annular valve for movement.

Y (AP-circ.) ^\u003d Y (tubing) - Y (rods) (8) g de Y ( _AP . _circus ) - the volume of AP pumped with an open annular valve, m ³ ;

V( _HKT ) - internal volume of tubing, m ³ ;

U( _rods ) - displacement of rods, m ³ ; (for ESP V( _rod ) = 0).

The second stage is the injection of the remaining volume of the AP into the tubing and its displacement to the bottomhole with the annular valve closed with the killing fluid in the volume:

V(npod.) - U(tubing) ^_ U(rods) + U(well under GNO) ^_ U(AP) + 1 (9)

U(prod.) \u003d 0.001 * UnKT (sp.) * h (HKT) - V (rods) + 0. 001 * U _K (sp.) * (L (current zab.) - h (HKT) ) - Y(AP) + 1 (10) where Y( _prod ) - the volume of the killing fluid pumped into the squeezing with the annular valve closed, m ³ ;

0.001 - conversion factor dm ³ (l) to m ³ ;

Y k.( _sp ) - specific internal volume of the casing string under GNO, dm ³ /m;

bwkt) - pump or tubing suspension depth, m;

b( _te k. _zab .) - depth of the current face, m;

U _tubing ( _sp .) - specific internal volume of tubing, dm ³ /m;

U ( _rods ) - displacement of rods, m ³ ; (with ESP Y( _rods )= 0);

- 5 040038

V ( _A n) is the volume of AP, m ³ ;

V ( _CKB . _{under GNO} ) is the volume of the well under GNO, m ³ ;

V (HKT) - internal volume of the tubing, m ³ ;

- reserve volume of killing fluid for squeezing AP into the reservoir, m ³ .

When pushing the AP to the bottom of the well during killing by direct injection, it is recommended not to exceed the maximum pressure on the pump hanger, the pressure of the pressure test of the string and cable entry (as a rule, up to a maximum of 60 atm).

After installing the AP at the bottom of the well, the killing operation ends with the replacement of the annular volume of the well fluid with the estimated volume of the killing fluid:

where V( _sα m _esch ) - the volume of killing fluid pumped into the tubing for circulation to replace the annular fluid, m ³ ;

0.001 - conversion factor dm ³ (l) to m ³ ;

V _annulus .( _ud ) - specific volume of the annulus, dm ³ /m;

h( _tubing ) - pump or tubing suspension depth, m;

1.5 - stock of killing fluid for full flushing with the release of a clean killing solution at the wellhead.

Installation of AP during jamming by reverse injection.

The first stage is the injection of AP into the annulus and finishing to the bottom of the tubing (or to the pump hanger) in circulation with the tubing valve open to move the killing fluid in the volume.

where V( _circus ) is the volume of killing fluid pumped with the tubing valve open, m ³ ;

V ( _exp .) - the volume of the annular space to the bottom of the tubing or to the pump suspension, m ³ ;

V ( _A π) - AP volume, m ³ .

The second stage is the AP squeezing with the tubing valve closed with the killing fluid in the volume: Y (prod.) - Y (exp.) + Y (well under GNO) ” U (AP) + 1 (13)

U(prod.) - 0.00 XUzatr. (sp.) * h(HKT) + 0.001 *Uk (sp.)*(11(current fl.) ^- h(HKT)) ^_ V (NPS 1 (14) where V( _prod ) is the volume of killing liquid, injected for squeezing with the tubing valve closed, m ³ ;

0.001 - conversion factor dm ³ (l) to m ³ ;

V _to .( _sp ) - specific internal volume of the casing string under GNO, dm ³ /m;

V _zatr .( _sp ) - specific internal volume of the annulus, dm ³ /m;

V ( _zatr .) - the volume of the annulus to the bottom of the tubing or pump suspension, m ³ ;

h(tubing) - pump or tubing suspension depth, m;

h( _{current zab} .) - depth of the current face, m;

V ( _AP ) - AP volume, m ³ ;

V ( _Ckb . _{under GNO} ) - well volume under GNO, m ³ ;

- reserve volume of killing fluid for squeezing AP into the reservoir, m ³ .

When pushing the AP to the bottom of the well by the method of reinjection, it is recommended not to exceed the pressure of the cable entry pressure test (usually 80 atm), the pressure pressure of the production string.

After installing the AP, the well is filled and flushed to a clean remaining volume (annular or pipe) with an aqueous solution of calcium chloride or potassium chloride with the addition of a water repellent brand IVV-1 or CHAS-M - 1-2 vol.%, close the pipe and annular valves, leave the well for balancing for 1 hour. After that, the excess pressure in the annular and tubular space is measured and, if necessary, balanced. Excess pressure is released through technological tubes to the trough tank.

AP is considered to be installed within the specified interval when pumping the estimated amount of killing fluid for delivery through the lift (in circulation mode), and pushing the estimated amount of killing fluid when it is installed at the bottom of the well (in pushing mode). At the end of the squeezing mode, the wellhead pressure may increase by 15-20 atm when the AP is set on the bottomhole.

To prevent premature removal of the AP from the bottomhole zone during tripping operations on a well that was killed using AP, it is prohibited to exceed the maximum lifting speed of the underground downhole equipment.

Deleting an active pack

It is recommended to remove the AP by transferring the well to oil and causing the inflow of fluids into the well. If it is not possible to transfer the well to oil, it is allowed to remove the AP by transferring the well to an aqueous solution of calcium chloride or potassium chloride with the addition of a water repellent of grades IVV-1 or CHAS-M - 1-2 vol.% and causing fluid inflow into the well. Inflow into the well can be caused by classical methods of well development. It is not recommended to induce fluid inflow into the well by starting the ESP. AP residues in filtration channels

- 6 040038 hydrocarbons are destroyed spontaneously during the inflow of well production during the first day.

To remove the AP without causing inflow from the reservoir, it is necessary to inject oil into the interval of the AP installation. Recommended oil consumption: volume 0.6-0.8 m ³ per 1 m ³ AP with displacement into the reservoir.

Laboratory studies of the physical properties of ES.

To study the physical properties of ES, samples with different volume content of components were prepared.

As a result of the experiments, the following ES parameters were determined: density; aggregative stability; thermal stability; kinematic viscosity.

After preparing the ES samples, they were held for at least 2 h at room temperature before the start of the experiments.

RES density study

The results of measuring the density of ES (pycnometric method) with the density of the water component - 1200 kg/m ³ and 1100 kg/m ³ are presented in the tables in Fig. 2 and 3.

Study of aggregative stability of ES

Aggregative stability is the ability of ES to maintain the degree of dispersion of the internal phase.

The evaluation was carried out according to the indicator of electrical stability - measurements of the values of the electrical voltage corresponding to the moment of destruction of the ES, enclosed between the electrodes of the measuring cell of the device. The experiments were carried out on a FANN device.

The results of measuring the aggregative stability of ES with the density of the water component - 1200 kg/m ³ are presented in the table in Fig. 4.

Study of ES thermal stability

The thermal stability of ES was measured by keeping them in measured hermetically sealed cylinders in a heating cabinet for 24 h at a given temperature regime of 80°C. The test was considered positive (the sample is stable) if, after 24 h of incubation, no more than 2 vol.% of water or hydrocarbon phase from the total volume of the ES was separated from the ES. As a result of experiments on thermal stability, it was determined that all samples are stable for 24 hours.

Study of the kinematic viscosity of ES

The results of studies of the kinematic viscosity of ES with a density of the water component of 1200 kg/m ³ are presented in the table in Fig. 5. The measurements were carried out at a temperature of 20°C (temperature measurement error ± 0.1°C) on a VPZh-2 viscometer with a viscometer constant of 0.09764. Before experiments, ES were stirred in a mechanical stirrer at a given speed of 1500 rpm for 20 min.

The results of a complex of basic laboratory studies of the physical properties of ESs confirmed the high technological properties of the developed composition. Particularly important parameters from the point of view of industrial application of ES are high thermal stability and aggregation stability, as well as the ability to control the viscous properties of ES by changing the volume fraction of constituent components depending on the porosity and geological and physical characteristics of the BFZ.

Method implementation examples

Example 1. Implementation of the method in an oil well. The index of water cut before killing the well is 54%.

Conducted preparatory work on the well.

They stopped the well, discharged it, checked the serviceability of the stop valves on the wellhead equipment. We checked the presence of circulation in the well and made a decision on the option of pumping process fluids - reverse injection. The value of the current reservoir pressure was determined. The equipment for jamming was arranged according to the approved scheme. The equipment was tied up and the discharge line was pressure tested to a pressure exceeding the expected operating pressure by 1.5 times, observing safety measures. The discharge line was equipped with a check valve.

Upon completion of the preparatory work, technological operations began to kill the well.

At the first stage, the perforated formation thickness (m ³ /m) of the following composition, vol.%, was injected into the bottomhole zone of the EPP in a volume of 2 m ³ /m: diesel fuel - 15, emulsifier -2, a colloidal solution of silicon dioxide nanoparticles - 0.5, an aqueous solution potassium chloride with a density of 1100 kg / m ³ - 82.5. At the same time, the emulsifier contains (vol.%): esters of higher unsaturated fatty acids (linoleic) and resin acids - 40, amine oxide - 0.7, high-molecular organic heat stabilizer (lime suspension in diesel fuel) - 0.5, diesel fuel (summer) - 58.8 . The colloidal solution of silicon dioxide nanoparticles contains (vol.%): amorphous silicon dioxide - 30, propylene glycol monomethyl ether - 68.5, water - 1.5.

At the second stage, an aqueous solution of calcium chloride containing water repellent IVV-1 (1 wt.%) with a density of 1085 kg/m ³ in a volume of 34 m ³ was injected into the BFZ.

- 7 040038

The well was killed in one cycle without complications. The water-cut index after the well was put into operation is 48%, the average after three months of well operation is 51%.

Example 2

Here and below, the preparatory work was carried out in accordance with the order indicated in example 1.

Implementation of the method by direct injection in an oil well. The index of water cut before killing the well is 78%.

At the first stage, injection into the bottomhole zone of the ES was carried out in a volume of 1.7 m ³ /m of the following composition, vol.%: diesel fuel - 16, emulsifier - 2.3, a colloidal solution of silicon dioxide nanoparticles - 0.7, an aqueous solution of potassium chloride with a density of 1100 kg/m ³ - 81. At the same time, the emulsifier contains (vol.%): esters of higher unsaturated fatty acids (linolenic) and resin acids - 41, amine oxide - 0.9, high-molecular organic heat stabilizer (lime suspension in diesel fuel) - 0.7, diesel fuel (summer) - 57.4. The colloidal solution of silicon dioxide nanoparticles contains (vol.%): amorphous silicon dioxide - 30.5 vol.%, propylene glycol monomethyl ether - 69 vol.%, water - 0.5 vol.%.

At the second stage, an aqueous solution of calcium chloride containing water repellent IVV-1 (1 wt.%) with a density of 1065 kg/m ³ was injected into the well in a volume of 27 m ³ .

The well was killed in one cycle without complications. The water-cut index after the well was put into operation is 70%, the average after three months of well operation is 73%.

Example 3. Implementation of the method of re-injection in an oil well. The index of water cut before killing the well is 47%.

At the first stage, injection into the bottomhole zone of the EPP was carried out in a volume of 3.3 m ³ /m of the following composition, vol.%: diesel fuel - 20, emulsifier 2.5, a colloidal solution of silicon dioxide nanoparticles - 1, an aqueous solution of potassium chloride with a density of 1200 kg/m ³ - 76.5 . At the same time, the emulsifier contains (vol.%): esters of higher unsaturated fatty acids (linolenic) and resin acids - 42, amine oxide - 1, high-molecular organic heat stabilizer (bentonite suspension in diesel fuel) - 0.8, diesel fuel (summer) - 56.2 . The colloidal solution of silicon dioxide nanoparticles contains (vol.%): amorphous silicon dioxide - 31.5, propylene glycol monomethyl ether - 68, water - 0.5.

At the second stage, an aqueous solution of calcium chloride was injected into the well containing the water repellent IVV-1 (2 vol.%) with a density of 1140 kg/m ³ in a volume of 38 m ³ .

The well was killed in one cycle without complications. The water-cut index after the well was put into operation is 39%, the average after three months of well operation is 42%.

Example 4. Implementation of the direct injection method in a gas well.

The well was killed in one cycle without complications.

At the first stage, injection into the bottomhole zone of the ES was carried out in a volume of 4 m ³ /m of the following composition, vol.%: diesel fuel - 25, emulsifier - 2.5, a colloidal solution of silicon dioxide nanoparticles - 1, an aqueous solution of potassium chloride with a density of 1100 kg/m ³ - 71.5. At the same time, the emulsifier contains (vol.%): esters of higher unsaturated fatty acids (oleic) and resin acids - 42, amine oxide - 1, high-molecular organic heat stabilizer (lime suspension in diesel fuel) - 1, diesel fuel (winter) - 56 The colloidal solution of silicon dioxide nanoparticles contains (vol.%): amorphous silicon dioxide - 32.5, propylene glycol monomethyl ether - 67, water - 0.5.

At the second stage, an aqueous solution of potassium chloride was injected into the well containing the water repellent CHAS-M (2 vol.%) with a density of 1085 kg/m ³ in a volume of 40 m ³ .

Example 5. Implementation of the method by direct injection in a gas well.

The well was killed in one cycle without complications.

At the first stage, injection into the bottomhole zone of the ES was carried out in a volume of 4.5 m ³ /m of the following composition, vol.%: diesel fuel - 27, emulsifier - 3, a colloidal solution of silicon dioxide nanoparticles - 1, an aqueous solution of potassium chloride with a density of 1110 kg/m ³ - 69. At the same time, the emulsifier contains (vol.%): esters of higher unsaturated fatty acids (oleic) and resin acids - 42, amine oxide - 1, high-molecular organic heat stabilizer (bentonite suspension in diesel fuel) - 1, diesel fuel (winter) - 56. A colloidal solution of silicon dioxide nanoparticles contains (vol.%): amorphous silicon dioxide - 32.5, propylene glycol monomethyl ether - 67, water - 0.5.

At the second stage, an aqueous solution of potassium chloride containing water repellent CHAS-M (2 wt.%) with a density of 1090 kg/m ³ in a volume of 36 m ³ was injected into the well.

Example 6. Implementation of the method of re-injection in an oil well. The indicator of water cut before killing the well is 39%.

At the first stage, the following composition was injected into the BFZ of the ES in a volume of 2 m ³ /m of the following composition, vol.%: diesel fuel - 30, emulsifier - 3, a colloidal solution of silicon dioxide nanoparticles - 1, an aqueous solution of potassium chloride with a density of 1180 kg/m ³ - 66. At the same time, the emulsifier contains (vol.%): esters of higher unsaturated fatty acids (oleic) and resin acids - 42, amine oxide - 1, high-molecular organic heat stabilizer (lime suspension in diesel fuel) - 1, diesel fuel (winter) - 56. A colloidal solution of silicon dioxide nanoparticles contains (vol.%): amorphous silicon dioxide - 31.5, propylene glycol monomethyl ether - 68, water - 0.5.

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At the second stage, an aqueous solution of potassium chloride was injected into the well containing the water repellent IVV-1 (2 wt.%) with a density of ISO kg/m ³ in a volume of 41 m ³ .

The well was killed in one cycle without complications. The water-cut index after the well was put into operation is 35%, the average after three months of well operation is 37%.

Example 7. Implementation of the method of re-injection in an oil well. The water cut before killing the well is 65%.

At the first stage, injection into the bottomhole zone of the ES was carried out in a volume of 3.6 m ³ /m of the following composition, vol.%: diesel fuel - 30, emulsifier - 3, a colloidal solution of silicon dioxide nanoparticles - 1, an aqueous solution of potassium chloride with a density of 1200 kg/m ³ - 66. At the same time, the emulsifier contains (vol.%): esters of higher unsaturated fatty acids (oleic) and resin acids - 40, amine oxide - 0.7, high-molecular organic heat stabilizer (lime suspension in diesel fuel) - 0.5, diesel fuel (winter) - 58.8. The colloidal solution of silicon dioxide nanoparticles contains (vol.%): amorphous silicon dioxide - 30.5, propylene glycol monomethyl ether - 68.5, water - 1.

At the second stage, an aqueous solution of potassium chloride containing water repellent IVV-1 (2 wt.%) with a density of 1160 kg/m ³ in a volume of 46 m ³ was injected into the well.

The well was killed in one cycle without complications. The water-cut index after the well was put into operation is 59%, the average after three months of well operation is 57%.

Example 8. Implementation of the method of re-injection in an oil well. Water cut before well killing is 32%.

At the first stage, injection into the bottomhole zone of the ES was carried out in a volume of 2.7 m ³ /m of the following composition, vol.%: diesel fuel - 30, emulsifier - 3, a colloidal solution of silicon dioxide nanoparticles - 1, an aqueous solution of potassium chloride with a density of 1160 kg/m ³ - 66. At the same time, the emulsifier contains (vol.%): esters of higher unsaturated fatty acids (linoleic) and resin acids - 40, amine oxide - 0.7, high-molecular organic heat stabilizer (lime suspension in diesel fuel) - 0.5, diesel fuel (summer) - 58.8. The colloidal solution of silicon dioxide nanoparticles contains (vol.%): amorphous silicon dioxide - 32.5, propylene glycol monomethyl ether - 67, water - 0.5.

At the second stage, an aqueous solution of potassium chloride was injected into the well containing the water repellent IVV-1 (2 wt.%) with a density of 1100 kg/m ³ in a volume of 44 m ³ .

The well was killed in one cycle without complications. The water cut index after the well was put into operation is 28%, the average after three months of well operation is 26%.

Example 9. Implementation of the method of re-injection in an oil well. The index of water cut before killing the well is 41%.

At the first stage, the following composition was injected into the bottomhole zone of the EPP in a volume of 3.1 m ³ /m of the following composition, vol.%: prepared oil from the point of preparation and pumping of oil - 27, emulsifier - 2.5, a colloidal solution of silicon dioxide nanoparticles - 0.8, an aqueous solution of chloride potassium density ISO kg / m ³ - 69.7. At the same time, the emulsifier contains (vol.%): esters of higher unsaturated fatty acids (linolenic) and resin acids - 41, amine oxide - 0.7, high-molecular organic heat stabilizer (bentonite suspension in diesel fuel) - 0.5, diesel fuel (summer) - 42.2 . The colloidal solution of silicon dioxide nanoparticles contains (vol.%): amorphous silicon dioxide - 30, propylene glycol monomethyl ether - 69, water - 1.

At the second stage, an aqueous solution of potassium chloride was injected into the well containing the water repellent CHAS-M (1.5 wt.%) with a density of 1100 kg/m ³ in a volume of 47 m ³ .

The well was killed in one cycle without complications. The water cut index after the well was put into operation is 35%, the average after three months of well operation is 33%.

Example 10. Implementation of the method of re-injection in an oil well. The water cut before killing the well is 53%.

At the first stage, injection into the bottomhole zone of the EPP was carried out in the amount of ⁴ m 1200 kg / m ³ - 72. At the same time, the emulsifier contains (vol.%): esters of higher unsaturated fatty acids (linolenic) and resin acids - 40, amine oxide - 0.7, high-molecular organic heat stabilizer (bentonite suspension in diesel fuel) - 0.5 , diesel fuel (summer) - 58.8. The colloidal solution of silicon dioxide nanoparticles contains (vol.%): amorphous silicon dioxide - 31.5, propylene glycol monomethyl ether - 68, water - 0.5. At the second stage, an aqueous solution of potassium chloride containing water repellent CHAS-M (1.5 wt.%) with a density of 1180 kg/m ³ was injected into the well in a volume of 42 m ³ .

The well was killed in one cycle without complications. The water cut index after the well was put into operation is 50%, the average after three months of well operation is 48%.

Example 11. Implementation of the method of re-injection in an oil well. The indicator of water cut before killing the well is 77%.

At the first stage, injection into the bottomhole zone of the EPP was carried out in a volume of 3.3 m ³ /m of the following composition, vol.%: prepared oil from the point of preparation and pumping of oil - 25, emulsifier - 2.5, a colloidal solution of silicon dioxide nanoparticles - 0.7, an aqueous solution of potassium chloride with a density 1180 kg / m ³ - 71.8. At

- 9 040038 this emulsifier contains (vol.%): esters of higher unsaturated fatty acids (linolenic) and resin acids - 42, amine oxide -0.9, high-molecular organic heat stabilizer (bentonite suspension in diesel fuel) - 0.8, diesel fuel (winter) - 56.3. The colloidal solution of silicon dioxide nanoparticles contains (vol.%): amorphous silicon dioxide - 32, propylene glycol monomethyl ether - 67.5, water - 0.5.

At the second stage, an aqueous solution of potassium chloride was injected into the well containing the water repellent CHAS-M (1 wt.%) with a density of 1150 kg/m ³ in a volume of 36 m ³ .

The well was killed in one cycle without complications. The water cut index after the well was put into operation is 73%, the average after three months of well operation is 71%.

Thus, the invention provides an increase in the efficiency of geological and technical measures for killing oil and gas wells, high thermal stability and aggregative stability of the emulsion system for killing wells, as well as the ability to control the surface-active properties and viscosity of the emulsion system depending on the reservoir and geological physical characteristics of the bottomhole formation zone.

Claims (1)

CLAIM A method for killing oil and gas wells, including successive injection of an active pack and displacement fluid into the bottomhole formation zone, while an emulsion system containing (vol.%) is used as an active pack: diesel fuel or prepared oil from the point of preparation and pumping of oil - 15-30, emulsifier - 2-3, colloidal solution of hydrophobic silicon dioxide nanoparticles - 0.5-1, aqueous solution of calcium chloride or potassium chloride - the rest, while the specified emulsifier contains (vol.%): esters of higher unsaturated fatty acids and resin acids - 40-42, amine oxide - 0.7-1, high-molecular organic heat stabilizer - 0.5-1, diesel fuel - the rest, the specified colloidal solution of hydrophobic dioxide nanoparticles silicon contains (vol.%): amorphous silicon dioxide - 31-32.5, propylene glycol monomethyl ether - 67-69, water - the rest, and an aqueous solution of calcium chloride or potassium chloride with the addition of 1-2 vol. % water repellent brand IVV-1 or CHAS-M, where the water repellent IVV-1 is a mixture of alkyl dimethyl benzyl ammonium chloride and a quaternary ammonium salt of a tertiary amine, obtained by condensation of alkyl dimethyl amine and benzyl chloride, and the water repellent CHAS-M is a water-alcohol solution of quaternary ammonium salts of alkyldimethylamine.