RU2812983C1 - Method for producing high-viscosity oil with in-well thermal activation of binary solution - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is applicable for horizontal or inclined multifunctional wells that combine the functions of production and injection. In the method of producing high-viscosity oil with in-well thermal activation of a binary solution, a well is first equipped, then a binary solution is injected containing, wt.%: ammonium nitrate - 27.8; sodium nitrite - 32.2; water - 40, which is supplied through the annular gap, bypass pipe and lower column to the end section of the casing pipe. Next, the said binary solution, through the first exposed zone or the second exposed zone, enters the productive formation and then it is pressed with light oil with a density of no more than 0.92 g/cm³. Next, downhole thermal activation of the exothermial chemical reaction of the injected binary solution is started by the method of simultaneously and separately injecting the said binary solution and the activator - copper sulphate - through a mixing reactor at the ratio, m³: binary solution: activator - copper sulphate = 1:0.02. In this case, an instant exothermal reaction occurs in the mixing reactor with the release of hot gases and vapours, the temperature of which exceeds by more than 60 °C the activation temperature of the previously injected binary solution, injection of the binary solution and the copper sulphate activator ends with the launch of the chemical reaction of the binary solution, which is determined by the increase in pressure and temperature on the installed control devices. Next, a chain chemical reaction begins with the release of heat sufficient to form a thermal front throughout the entire treated zone of the formation, an increase in pressure and temperature appears, which are recorded by sensors, and heat spreads in the porous medium by reaction products. The heat front heats up the highly viscous oil in the reservoir. The resulting heated oil-water emulsion with reaction products flows through the first opened zone into the annulus between the lower column and the initial section of the casing, then it enters through a built-in adjustable valve to receive a submersible pump, then it is pumped to the surface through an additional pipe. When the flow rate decreases, pumping is stopped and the binary solution is reinjected into the productive zone of the formation through the lower column to increase oil fluidity, then pumping is carried out and the cycles are repeated.

EFFECT: increased oil recovery, ability to choose the time from the start of binary solution injection to the start of initiation of a chain exothermial reaction, ability to delay the onset of chemical exposure of the binary solution to the bottomhole zone without the risk of premature initiation of the chemical reaction.

1 cl, 3 dwg, 1 tbl, 1 ex

Description

The invention relates to the oil production industry, in particular to a method for thermogas-chemical treatment of the bottomhole and remote zones of a formation with heavy and highly viscous oil. The method is applicable for horizontal or inclined multifunctional wells that combine the functions of production and injection; it is characterized by the fact that the formation is heated by injection of a binary solution (BS) using the simultaneous separate injection of a BR activator to start an exothermic chain reaction.

The invention can be used under conditions of normal and low reservoir temperatures to reduce oil viscosity. It can also be used in conditions of normal and low reservoir pressures, to increase the permeability of the bottomhole and remote zones of the productive formation by creating additional cracks and cavities. In addition to the above, the invention can be used to activate or renew oil wells, the productivity of which is reduced due to paraffin-hydrate and asphaltene-resin deposits contaminating filtration channels.

Further in the text, the applicant provides a definition of the terms that are necessary to facilitate a clear understanding of the essence of the declared materials and to eliminate contradictions and/or controversial interpretations when performing substantive examination.

Tubing - pump and compressor pipe.

BR is a binary solution consisting of a mixture of aqueous solutions of inorganic salts of sodium nitrite and ammonium nitrate (ammonium nitrate).

BS is a binary composition consisting of BR and an activator, for example copper sulfate.

IR - initiating solution - an aqueous solution of the initiating reagent.

TC - thermogas-chemical composition.

Light oil - by this term in the context of this description the applicant understands oil with a density of no more than 0.92 g/cm ³ .

NGLs are a wide fraction of light hydrocarbons.

Since the 2000s, domestic scientists have been actively conducting research in the development and application of thermogas-chemical treatment methods using binary compositions. In particular, there is great interest in the use of initiating additives that make it possible to control the reaction onset time [Patent RU 2525386 “Thermogas-chemical composition and method of use for treating the bottomhole and remote zone of the productive formation”], [Ogata Y. Kinetics of the Reaction of Aromatic Aldehydes with Ammonia / Y. Ogata, A. Kawasaki, N. Okumura. // J. Org. Chem. - 1964. - No. 7. - P. 1985-1988], [Ogata Y. Kinetics of the condensation of urea with some aliphatic aldehydes / Y. Ogata, A. Kawasaki, N. Okumura // Tetrahedron. - 1966, - No. 22. - P. 1731-1739], [Patent RU 2675617 “Method of thermal acid treatment of oil and gas bearing formations”], [Patent RU 2525386 “Thermogas-chemical composition and method of application for treating the bottom-hole and remote zone of the productive formation”].

However, the inventions presented above are complex multi-component systems. Due to the multicomponent nature of such systems, the implementation of technologies based on them in field conditions is very difficult.

Analysis of the literature data allows us to state that at the date of submission of application materials, the most studied are commercially available additives based on aldehydes, organic and inorganic acids and aqueous solutions of inorganic salts [Patent RU 2717151 “Method of thermogas-chemical and shock wave treatment of oil-bearing formations”].

In the invention according to patent RU No. 2778919 “Method for extracting high-viscosity oil and thermogas-chemical composition for its implementation,” the essence is:

1. Thermogas-chemical composition for the production of high-viscosity oil, consisting of wt.%:

- sodium nitrite - 27.8;

- ammonium nitrate - 32.2;

- copper sulfate - 0.12;

- water - the rest.

2. A method for producing high-viscosity oil, which consists in first equipping a well, for which it is lined with a casing pipe that has first and second opened zones in a horizontal or inclined section, then lower and upper heat-resistant packers are lowered into the well, connected to each other by an injection perforated pipe, connect the lower column, on top of which a coaxially perforated fluid sampling pipe is put on, then a heat-resistant separation packer is installed that limits the interpipe space, and a support with a built-in adjustable valve is screwed into the perforated fluid sampling pipe, a submersible pump is connected and a bypass pipe is inserted into the support from above, corresponding along the length of the submersible pump, a tee is mounted on the free end of the bypass pipe and the outlet of the submersible pump, on the opposite side of which the upper column is screwed and an additional pipe with an annular gap is inserted up to the tee with an annular gap, at the end of which the tee is attached; then the annular space between the casing pipe and the upper column is filled with water, in the lower part the movement of water is limited by a separation heat-resistant packer and a built-in adjustable valve in the support, then the thermogas-chemical composition is pumped according to claim 1, which is fed into the annular gap, bypass pipe and lower column the end section of the casing pipe, then the thermogas-chemical composition through the first opened zone or the second opened zone enters the productive formation and then it is pressed with light oil, the activation time of the exothermic chemical reaction and the heating time of high-viscosity oil in the formation are maintained, then the heated oil-water emulsion with unreacted reaction products drains through the first opened zone into the annulus between the lower column and the initial section of the casing, then the heated oil-water emulsion enters through a built-in adjustable valve to receive a submersible pump, the heated oil-water emulsion is pumped to the surface through an additional pipe; when the flow rate decreases, pumping is stopped and the thermogas-chemical composition is reinjected into the productive zone of the formation through the lower column to increase oil fluidity, then pumping is carried out and the cycles are repeated.

Thus, in order to develop new delayed-action binary compositions with controlled reaction onset times at low temperatures, initiating additives belonging to different classes of chemical compounds were used. In particular, additives based on carboxylic acids were used. It was determined that the addition of an initiator based on a carboxylic acid makes it possible to achieve a delay time for the activation of a binary solution of 1 hour, and an initiator based on an inorganic salt made it possible to achieve a reaction delay time of 2 hours. Thus, the known composition can be recommended for use in large-volume injections of BS deep into the formation.

From the researched level of technology, the applicant identified analogues of the claimed technical solution.

The invention is known according to RF patent No. 2580330 “Method for developing an oil reservoir”, the essence is a method for developing an oil reservoir, consisting of pumping a displacing agent through a well into the formation and withdrawing reservoir oil from the well, characterized in that in the zone of the formation, which is pinched out or replaced by non-oil-saturated rock, the well is drilled vertically through the oil formation, the well is continued under the formation and at the required distance from the first intersection, the well is again drilled through the formation vertically and in the opposite direction, that is, from the bottom up, the well constructed in this way is lined with a production casing, cemented along the entire length wells and perforate at the intersection of the well with the formation, well development is carried out sequentially - at the first stage, the remote zone is developed, and then the near zone of the first intersection of the oil reservoir by the well, the well is completed with two strings of tubing, the first of which is brought to the bottom formation in the zone of the second - distant intersection of the well with the formation and is packed in the casing string below the formation, and the second tubing string is equipped with a downhole pump, lowered into the well to the required depth above the formation in the zone of its first intersection, the development of the formation is carried out by pumping a displacing agent into the formation, in particular, water, through the first tubing column, and oil is withdrawn from the formation using a deep pump and the second tubing column.

The invention is known according to RF patent No. 2594027 “Method of well development of an oil reservoir section”, the essence is a method of well development of an oil reservoir section, consisting of injection of a displacement agent into the formation and selection of reservoir oil, characterized in that a well is built in which the horizontal part of the casing is located directly in a section of an oil reservoir with homogeneous properties and has a C-shaped appearance, where in succession the first and third sections of the casing string have the same length and the required density of perforations and are located parallel to each other, and the second section connects them into a single casing string, and the space between the casing string of the second section and the formation rock is filled with cement mortar, a string of tubing or coiled tubing pipes is lowered into the well to the boundary of the second and third sections of the casing string, and the annular space in this boundary zone between the casing string and this pipe string is sealed with using a packer, plane-parallel filtration of the displacing agent and formation oil is organized in the oil reservoir section by pumping the displacing agent into the formation using a tubing string or coiled tubing through the perforations of the final - third horizontal section of the casing, and oil is withdrawn from the formation through the perforations the first horizontal section of the casing using flow or mechanized operation of the well, in which oil is lifted to the wellhead through the annular - intertubular space of the well, and to organize real-time monitoring of the injection of a displacing agent and the selection of reservoir oil into the well in the zones of the first and third sections The casing is equipped with pressure and temperature sensors.

The invention is known under RF patent No. 2646902 “Method for developing a high-viscosity oil deposit”, the essence is a method for developing a high-viscosity oil deposit, which consists of pumping a displacement agent into the formation through a horizontal section of a multifunctional well and withdrawing reservoir oil from a perforated section of the same well, located horizontally and parallel agent injection zone, characterized in that along the length of the strip-shaped element (PE) of the oil deposit or the selected direction of the deposit, multifunctional wells are located sequentially one after another so that in the reservoir zone between the areas of agent injection and oil extraction of each well, two more sections of two adjacent ones are located multifunctional wells: closer to the oil extraction area of the well, the agent injection area of the adjacent well is located on the left side, and closer to the agent injection area of the well in question, the oil extraction area of the second adjacent well is located on the right side along the length of the PE or the selected direction, with the considered horizontal sections of all wells are located parallel to each other at the same distance from each other and across the length of the strip-shaped element, and the development of the oil deposit is carried out by dividing the deposit into strip-shaped elements over its entire area, each of which is developed using a system of multifunctional wells located within the boundaries of the PE according to the principle described above.

The known inventions described above are united by the fact that they use multifunctional wells, where in one casing two pipes are located next to each other, one for supplying a displacing agent and/or coolant in the form of steam, and the displaced fluid is produced through the other pipe.

The disadvantages of the inventions described above according to RF patents No. 2580330, No. 2594027 and No. 2646902 are:

- high energy consumption for heating superheated steam;

- heat loss when steam passes through the wellbore;

- negative impact on the operation of submersible pumps during the passage of steam, which leads to their overheating and failure.

The invention is known according to RF patent No. 2637259 “Thermogas-chemical binary composition and method of application for treating the bottom-hole and remote zones of an oil and gas-bearing formation.” The essence is a thermogas-chemical binary composition for treating the bottomhole and remote zones of an oil and gas bearing formation, containing equimolar solutions of ammonium salts of mineral acids and alkali metal nitrites with an initiating solution, characterized in that aldehyde solutions containing alcohols or acetone are used as an initiating solution, converting aldehyde groups into hemiacetals, which have a reduced reactivity, which provides an induction period sufficient for the safe injection of initial reagents into the oil and gas bearing formation. A method for treating the bottomhole and remote zones of an oil and gas bearing formation, including injection into the formation of a thermogas-chemical binary composition - solutions of ammonium salts of mineral acids and alkali metal nitrites with an initiating solution, characterized in that the solutions of ammonium salts of mineral acids and alkali metal nitrites are mixed with the initiating solution intensive mixing mode before the start of injection of a thermogas-chemical binary composition into an oil and gas bearing formation, and aldehyde solutions containing alcohols or acetone are used as an initiating solution, converting aldehyde groups into hemiacetals, which have a reduced reactivity, which provides an induction period sufficient for the safe injection of initial reagents into an oil and gas bearing formation.

The disadvantage of the known technical solution is that:

- production is carried out periodically, first by injection of a thermogas-chemical binary composition, followed by lifting the tubing and then lowering the pumping equipment, the maximum possible pumping and then stopping and then the tripping operations are repeated with the injection of a new portion of the thermogas-chemical binary composition, thus, the known technology allows saving on one well colossal material resources, because one lowering and lifting of tubing costs approximately 5 million rubles;

- it is not possible to produce high-viscosity oil from inclined and horizontal wells, because in the known invention there is no lower packer and bypass pipe (present in the claimed technical solution), which, together with the pump, can be installed in a vertical, inclined and horizontal position, in contrast from the declared technical solution, which significantly increases the efficiency of application of the declared technical solution;

- there is no possibility to change the perforation zone (opened zone) for pumping out fluid and injecting a binary composition without raising the pump to the surface, due to the absence of a lower packer, which also affects the effectiveness of the known technical solution;

- there is a decrease in the concentration of the binary composition as a result of the fact that the BS is diluted in the wellbore with water, since injection is carried out into an open bottom hole;

- difficult to implement temperature range for the preparation of initiating additives, because the process of preparing BS occurs with the absorption of thermal energy, thereby increasing the time interval for preparing BS;

- impossibility of application in “cold” formations, with a temperature of no more than 100°C due to the crystallization of the known composition of the BS and its precipitation, resulting in clogging of the tubing pipe.

From the researched level of technology, the article “Numerical modeling of thermal effects when treating wells with solutions of binary mixtures” was identified [UDC 622.236; 622.276.6, Varavva A. I., Vershinin V. E. © Online publication “Oil and Gas Business”. 2017. No. 6] [http://ogbus.ru/files/ogbus/issues/6_2017/ogbus_6_2017_p20-34_VaravvaAI_ru.pdf]. The essence is the effectiveness of the method for increasing the productivity of wells when they are treated with aqueous solutions of binary mixtures. After the solution is pumped into the formation, an exothermic interaction reaction between the components of the binary mixture is initiated, accompanied by the release of gases. The impact of heated chemical reaction products on the bottomhole zone of oil wells is combined and comes down to three phenomena: heating of the rock and the oil contained in it; cleaning the bottomhole zone from paraffins, resins and clogging deposits; expansion of the system of natural cracks and the appearance of artificial cracks. As a result of treatment, two areas are formed near the well: increased conductivity and increased temperature, where the viscosity of the oil decreases. The sizes of the areas may not be the same. Each area contributes to increasing well productivity. In this work, using mathematical and numerical modeling methods, the processes of thermal impact of chemical reaction products on the formation are studied and the increase in well flow rate is assessed due to a decrease in oil viscosity. A mathematical model of the reaction process of the components of a binary mixture, their filtration and influence on the reservoir system is proposed. The results of numerical modeling of the reaction process of a binary mixture and subsequent oil production from a heated reservoir are presented. Estimates were obtained for the increase in temperature and the size of the heating area during an exothermic chemical reaction in the pore space, as well as the expected increase in oil production and the duration of the effect. The cases of different concentrations of salts of the binary system were studied. The method has been shown to be highly economical based on the thermal effects of increased production. The known technical solution was used by the applicant as a mathematical model for selecting the optimal formulation of the claimed composition.

The disadvantage of the known technical solution is the use of a high concentration of binary solution, which can lead to precipitation, especially if the well temperature drops below 100°C.

The invention is known under RF patent No. 2639003 “Method for producing high-viscosity oil.” The essence is a method for extracting high-viscosity oil from a well, including equipping the well with a casing pipe with two exposed zones on a horizontal or inclined section, lowering a lower string of tubing pipes with a heat-resistant packer into the casing until it takes a position between the exposed zones, lowering a submersible pump on the upper tubing string to the first opened zone, cyclic injection of coolant through the lower tubing string and lifting the oil-water emulsion to the surface by a submersible pump, characterized in that before lowering the lower tubing string with a heat-resistant packer is connected at the upper end to the bypass pipe , mounted on a submersible pump, and lower them together on the upper string of tubing pipes, into which, upon completion of the lowering, an additional pipe is inserted with an annular gap; for pumping coolant into the lower string of tubing pipes, it is delivered through the annular gap and a bypass pipe, and the rise The water-oil emulsion is delivered to the surface through an additional pipe hydraulically connected to the discharge of the pump.

The disadvantages of the known technical solution are:

- additional energy consumption for heating the coolant due to the fact that when pumping coolant (steam or hot water) from the surface into the well while moving towards the perforation zone (opened zone), the coolant loses its temperature;

- the need to install thermal insulation of the submersible pump from the coolant passing nearby, since the pump requires a heat sink during operation;

- insufficiently heated produced oil settles on the walls of the tubing, while moving to the surface, in the form of paraffin deposits, which over time complicate the operation of the pump or make its operation impossible, because the pump overheats and fails.

The source is known [“Test results of binary systems based on ammonium nitrate and sodium nitrite with new oxidation initiators”, S.G. Uvarov, Ant. N. Beregovoy, N.A. Knyazeva, R.Sh. Ziatdinova, M.A. Rozova (TatNIPIneft), Collection of scientific works of TatNIPIneft, volume No. LXXXVII, PJSC Tatneft, 2019, pp. 132-136, UDC: 622.276.65-97, Publisher: ZAO Publishing House "Oil Industry" (Moscow)] . The essence is the study of two-component combustible-oxidizing systems of solutions or suspensions based on ammonium nitrate and nitrous acid salts with new oxidation initiators. As a basic, best-studied thermochemical composition, two-component combustible-oxidizing systems of solutions or suspensions based on ammonium nitrate and nitrous acid salts are proposed, the exothermic reaction between which increases the temperature at the bottom of the well to 400°C.

At a temperature of 60-70°C, active decomposition of ammonium nitrite occurs with the release of heat and nitrogen gas. The enthalpy of the reaction, calculated according to Hess's law, is about 300 kJ/mol. However, in a weakly acidified solution, the reaction rate increases significantly, which can end explosively.

When calculating the heat of thermochemical reactions and the heating temperature of the reaction mixture depending on the concentration of reagents in 1 m ³ of a binary mixture based on ammonium nitrate produced by JSC Ammoniy, it is accepted that the thermochemical reaction proceeds under isothermal conditions. The following equation of thermochemical reactions is taken as a basis:

NH ₄ NO ₃ +NaNO ₂ → N ₂ +2H ₂ O+NaNO ₃ , ΔН=316 kJ/mol,

where ΔН is enthalpy.

The amount of heat required to heat the body, Q=cm (t 2 - t 1),

where Q is the amount of heat, J; c is the specific heat capacity of the solution, J/(kg⋅°C), for calculations the specific heat capacity of water at a temperature of 25°C was taken; с=4179 J/(kg⋅°С); m is the mass of the solution, kg; t 2 - final solution heating temperature obtained experimentally, °C; t 1 is the initial temperature of the solution, °C; for calculations, t 1 = 25 °C is taken.

As a result of reactions in 1 m ³ of a 70% solution of a binary mixture prepared in an equimolar ratio, about 1875 MJ of thermal energy is released, and the temperature of the aqueous solution can increase to 400-450 ° C. In this case, 6248 kmol of nitrogen gas is released, which can increase the pressure in the system by 230 MPa.

The known technical solution allows for in-well heating of the BD, which is used by the applicant for sequential heating of the formation front, as a chain reaction occurs.

The source is known [“Binary compositions of delayed action for thermogas-chemical influence on the formation”, Andriyashin V.V., Milyutina V.A., Varfolomeev M.A. KMG Engineering LLP, Collection of abstracts of the International Scientific and Practical Conference “Prospects for the use of chemical methods of enhanced oil recovery (EOR) at the late stage of development”, September 16, 2022, Republic of Kazakhstan, Nur-Sultan, 2022. - from .11] the activity of binary compositions at various percentage and temperature parameters was considered.

In order to select the optimal concentration of the binary composition, solutions containing 30, 40, 50, 60% of active components (sodium nitrite and ammonium nitrate) in an equimolar ratio were studied.

During the experiment, the decomposition of the binary composition was initiated by a thermal method - by heating the solution to a temperature of 60-80°C.

It was found that with an increase in the concentration of BR, an increase in the temperature and pressure of the reaction is observed, which is certainly related to the amount of active components in the solution. Thus, with a total salt content of 30% in the solution, the peak reaction temperature was 125°C, and the pressure reached 7 atmospheres. An increase in the content of sodium nitrite and ammonium nitrate in the BR composition leads to an increase in peak pressure and temperature values. The maximum thermobaric parameters of the reaction were achieved at a BR concentration of 60% and amounted to 65.3 atmospheres at 262°C. Thus, the composition containing 60% active components was chosen as the optimal composition. The characteristics of the studied compositions, as well as the thermobaric parameters of the reactions, are presented in Table 1.

Table 1 - Parameters of binary solutions Weight of solution, g _NaNO2 , g NH ₄ NO ₃ , g BR concentration, % T reaction start, ° Tmax, ° Rmax, atm 40 6.44 5.56 thirty 63.6 125 7 40 8.59 7.41 40 64 170 12 40 10.73 9.27 50 64.4 211 26.6 40 12.88 11.12 60 63 262 65.3 40 15.03 12.97 70 56.3 260 72

The data shown in Table 1 is illustrated in Fig. 2a and 2b.

This source examines the activity of binary compounds at various percentage and temperature parameters, without reference to the technology and technical solution for its implementation.

The invention is known under RF patent No. 2748098 “Method for extracting high-viscosity oil and a device for its implementation.” The essence is a method for producing high-viscosity oil, which consists in first equipping a well, for which it is lined with a casing pipe having first and second opened zones in a horizontal or inclined section, then lower and upper heat-resistant packers are lowered into the well, connected to each other by an injection perforated pipe, connect the lower column, on top of which a coaxially perforated fluid sampling pipe is put on, then a heat-resistant separation packer is installed that limits the interpipe space, and a support with a built-in adjustable valve is screwed into the perforated fluid sampling pipe, a submersible pump is connected and a bypass pipe is inserted into the support from above, corresponding along the length of the submersible pump, a tee is mounted on the free end of the bypass pipe and the outlet of the submersible pump, on the opposite side of which the upper column is screwed and an additional pipe with an annular gap is inserted up to the tee with an annular gap, at the end of which the tee is attached; then the annular space between the casing pipe and the upper column is filled with water, in the lower part the movement of water is limited by a heat-resistant separation packer and a built-in adjustable valve in the support, then a binary composition is injected, which is supplied through the annular gap, the bypass pipe and the lower column to the end section of the casing pipe , then the binary composition through the first opened zone or the second opened zone enters the preheated productive formation and then it is pressed with water, the calculated activation time of the exothermic chemical reaction and the heating time of high-viscosity oil in the formation are maintained, then the heated oil-water emulsion with unreacted reaction products flows through the first the opened zone into the annulus between the lower column and the initial section of the casing pipe, then the heated oil-water emulsion enters through a built-in adjustable valve to receive a submersible pump, the heated oil-water emulsion is pumped to the surface through an additional pipe; when the flow rate decreases, pumping is stopped and the binary composition is reinjected into the productive zone of the formation through the lower column to increase the fluidity of oil, then pumping is carried out and the cycles are repeated. The method according to claim 1, characterized in that the processing of the productive formation is carried out with an increased distance between the first and second opened zones, but not more than the distance between the upper heat-resistant packer and the separation heat-resistant packer. A device for implementing the method according to claim 1 and claim 2, consisting of a lower column, a lower heat-resistant packer, an upper heat-resistant packer, a support, a submersible pump, a bypass pipe, a tee, an upper column, an additional pipe, a sealing element, a perforated fluid extraction pipe, a heat-resistant separation packer, a built-in adjustable valve, a perforated injection pipe, wherein the lower heat-resistant packer is connected to the perforated injection pipe; the injection perforated pipe is connected to the upper heat-resistant packer; the upper heat-resistant packer is connected to the lower string in such a way as to ensure fluid flow from the support into the injection perforated pipe; the lower column is connected to the support; the upper heat-resistant packer is connected to the perforated fluid sampling pipe in such a way as to ensure fluid flow through the hole in the support, in which the built-in adjustable valve is installed; a heat-resistant separation packer is installed on top of the perforated fluid sampling pipe; a submersible pump is connected to the built-in adjustable valve, while the submersible pump on the other side is connected to the tee in such a way as to make a connection with the sealing element; wherein the sealing element is further connected to an additional pipe with the possibility of ensuring free passage of the produced fluid to the surface; in this case, a bypass pipe is installed parallel to the submersible pump, which connects the support to the tee in such a way as to allow the flow of liquid from the upper column to the lower column.

The disadvantages of the known technical solution compared to the claimed technical solution are:

insufficient time from the start of BS injection to the start of the reaction due to the use of a binary composition instead of a thermogas-chemical composition, which entails less coverage of the treatment zone;

reduced oil recovery due to the fact that when the flow rate decreases, a binary composition is reinjected instead of the thermogas-chemical composition in the claimed technical solution;

additional energy and material costs for installing equipment due to the fact that the productive formation is preheated;

reducing the concentration of injected BS due to the fact that they are forced through with water, and not with light oil, as in the claimed technical solution;

the impossibility of controlling the quality of mixing of BS components with the activator due to the fact that mixing occurs directly in the well while moving along the tubing trunk.

The closest in terms of matching features, chosen by the applicant as a prototype, is the invention according to patent RU No. 2778919 “Method for the production of high-viscosity oil and the thermogas-chemical composition for its implementation”, the essence is a thermogas-chemical composition for the production of high-viscosity oil, consisting of, wt.%: sodium nitrite - 27.8; ammonium nitrate - 32.2; copper sulfate - 0.12; water - the rest. A method for producing high-viscosity oil, which consists in first equipping a well, for which it is lined with a casing pipe that has first and second exposed zones in a horizontal or inclined section, then lower and upper heat-resistant packers are lowered into the well, connected to each other by an injection perforated pipe, connect the lower column, on top of which a coaxially perforated fluid sampling pipe is put on, then install a heat-resistant separation packer that limits the annulus space, and screw a support with a built-in adjustable valve into the perforated fluid sampling pipe, connect a submersible pump and insert a bypass pipe into the support from above, corresponding to the length of the submersible pump, a tee is mounted on the free end of the bypass pipe and the outlet of the submersible pump, on the opposite side of which the upper column is screwed and an additional pipe with an annular gap is inserted up to the tee with an annular gap, at the end of which the tee is attached; then the annular space between the casing pipe and the upper column is filled with water, in the lower part the movement of water is limited by a separation heat-resistant packer and a built-in adjustable valve in the support, then the thermogas-chemical composition is pumped according to claim 1, which is fed into the annular gap, bypass pipe and lower column the end section of the casing pipe, then the thermogas-chemical composition through the first opened zone or the second opened zone enters the productive formation and then it is pressed with light oil, the activation time of the exothermic chemical reaction and the heating time of high-viscosity oil in the formation are maintained, then the heated oil-water emulsion with unreacted reaction products drains through the first opened zone into the annulus between the lower column and the initial section of the casing, then the heated oil-water emulsion enters through a built-in adjustable valve to receive a submersible pump, the heated oil-water emulsion is pumped to the surface through an additional pipe; when the flow rate decreases, pumping is stopped and the thermogas-chemical composition is reinjected into the productive zone of the formation through the lower column to increase oil fluidity, then pumping is carried out and the cycles are repeated.

The disadvantages of the prototype compared to the stated technical solution are:

the impossibility of arbitrarily choosing the time from the start of BS injection to the start of the reaction due to the lack of special thermal initiation methods;

insufficient oil recovery due to the smaller coverage area of simultaneous heating;

the impossibility of delaying the onset of the chemical impact of BS on the bottomhole zone for the required period, the possibility of premature start of a chemical reaction due to the presence of an activator in the BS composition;

the impossibility of starting a chain reaction of heat transfer for sequential heating of the formation front - heat transfer is explosive.

In FIG. 3 shows a table of comparative analysis with the prototype - invention according to RU patent No. 2778919.

The technical result of the claimed technical solution is to eliminate the shortcomings of the prototype, namely:

the ability to select the time from the start of BR injection to the start of initiation of an exothermic chain reaction through the use of simultaneous, separate injection of BR and activator;

increased oil recovery due to the fact that when the flow rate decreases, BR is reinjected and simultaneous separate injection of BR with an activator is used to heat up and begin to initiate an exothermic chain reaction;

the ability to delay the start of the chemical impact of BR on the bottomhole zone for the required period, without fear of premature start of a chemical reaction due to the absence of an activator in the BR;

the ability to launch a chain reaction of heat transfer for sequential heating of the formation front.

The essence of the claimed technical solution is a method for producing high-viscosity oil with in-well thermal activation of a binary solution, which consists in first equipping a well, for which it is lined with a casing pipe that has the first and second opened zones on a horizontal or inclined section, then the lower and second zones are lowered into the well. upper heat-resistant packers, interconnected by a perforated injection pipe, connect the lower column, on top of which a coaxially perforated fluid extraction pipe is put on, then install a separation heat-resistant packer that limits the interpipe space, and screw a support with a built-in adjustable valve into the perforated fluid extraction pipe, connect the submersible pump and a bypass pipe corresponding to the length of the submersible pump is inserted into the support from above, a tee is mounted on the free end of the bypass pipe and the outlet of the submersible pump, on the opposite side of which the upper column is screwed and an additional pipe with an annular gap is inserted up to the tee with an annular gap, at the end of which the tee is attached ; then the annular space between the casing and the upper column is filled with water, in the lower part the movement of water is limited by a heat-resistant separation packer and a built-in adjustable valve in the support; characterized by the fact that a binary solution is then pumped containing 27.8 wt.% ammonium nitrate, 32.2 wt.% sodium nitrite, the rest is water, which is supplied through the annular gap, bypass pipe and lower column to the end section of the casing pipe, then the binary solution enters the productive formation through the first opened zone or the second opened zone and is then forced through an inert buffer liquid with a density higher than the density of the binary solution; Next, the downhole thermal activation of the exothermic chemical reaction of the injected binary solution is started by the method of simultaneously and separately injecting a binary solution with an activator, for which a binary solution with an activator is simultaneously and separately injected into the mixing reactor in the ratio, m ³ : binary solution: activator = 1: 0, 02, in which an instant exothermic reaction occurs in the reactor with the release of hot gases and vapors, the temperature of which significantly exceeds the activation temperature of the previously pumped binary solution, the injection of the binary solution with the activator ends with the launch of the chemical reaction of the binary solution, which is determined by the increase in pressure and temperature on installed instruments control; then a chain chemical reaction begins with the release of heat sufficient to form a thermal front throughout the entire treated zone of the formation, an increase in pressure and temperature appears, which are recorded by sensors, heat spreads in the porous medium by reaction products; then the thermal front heats up the high-viscosity oil in the formation, then the heated oil-water emulsion with unreacted reaction products flows through the first opened zone into the annulus between the lower string and the initial section of the casing, then it flows through the built-in adjustable valve to receive a submersible pump, then it is pumped out to surface along an additional pipe; when the flow rate decreases, pumping is stopped and the binary solution is reinjected into the productive zone of the formation through the lower column to increase oil fluidity, then pumping is carried out and the cycles are repeated.

The claimed technical solution is illustrated in Fig. 1 - Fig. 3.

In FIG. Figure 1 shows a device on which the claimed method is carried out, where 1 - casing pipe, 2 - first opened zone, 3 - second opened zone, 4 - lower tubing string, 5n - lower heat-resistant packer, 5v - upper heat-resistant packer, 6 - support, 7 - submersible pump discharge, 8 - bypass pipe, 9 - tee, 10 - upper column, 11 - annular gap, 12 - additional pipe, 13 - sealing element, 14 - annulus, 15 - perforated fluid extraction pipe, 16 - separation heat-resistant packer, 17 - specially built-in adjustable valve, 18 - perforated injection pipe.

In FIG. Figure 2 shows graphs of thermobaric parameters of the reaction of a binary solution at different concentrations of sodium nitrite and ammonium nitrate salts: 2a - reaction temperature of a binary solution at different concentrations of sodium nitrite and ammonium nitrate salts, 2b - reaction pressure of a binary solution at different concentrations of sodium nitrite and ammonium nitrate salts.

In FIG. 3 shows a table of comparative analysis with the prototype - invention according to RU patent No. 2778919.

Next, the applicant provides a description of the claimed technical solution.

The claimed technical solution relates to a method for producing high-viscosity oil with in-well thermal activation of a binary solution and can be used in conditions of normal and low reservoir temperatures, to reduce oil viscosity, and can also be used in conditions of normal and low reservoir pressures, to increase the permeability of near-wellbore and remote zones productive formation by creating additional cracks and caverns. In addition to the above, the invention can be used to activate or renew oil wells, the productivity of which is reduced due to paraffin-hydrate and asphaltene-resin deposits contaminating filtration channels.

Below, the applicant provides information about the reagents used.

Sodium nitrite is a commercial product, for example, according to GOST 19906-74.

Ammonium nitrate (ammonium nitrate) is a commercial product, according to GOST 2-2013.

Next, the applicant provides a description of the preparation of the binary solution.

A binary solution (BS) for implementing the claimed method is prepared on the surface in a corrosion-resistant container and its quality and temperature are checked. A binary solution consists of an aqueous solution of two inorganic salts: sodium nitrite and ammonium nitrate.

Preparation of a binary solution

Take 27.8 wt.% (for example, 27.8 g) of ammonium nitrate, dissolve in 40 wt.% (for example, 40 g) of water distilled at a temperature of 20°C. The dissolution of ammonium nitrate occurs with decreasing temperature.

Next, 32.2 wt.% (for example, 32.2 g) of sodium nitrite is added to the cooled solution of ammonium nitrate and stirred until completely dissolved.

A binary solution is obtained containing 60 wt.% of active substances, of which 27.8 wt.% ammonium nitrate, 32.2 wt.% sodium nitrite, the rest is water. The selected ratio is optimal for starting the downhole thermal activation of an exothermic chemical reaction [“Binary compositions of delayed action for thermogas-chemical influence on the formation”, Andriyashin V.V., Milyutina V.A., Varfolomeev M.A. KMG Engineering LLP, Collection of abstracts of the International Scientific and Practical Conference “Prospects for the use of chemical methods of enhanced oil recovery (EOR) at the late stage of development”, September 16, 2022, Republic of Kazakhstan, Nur-Sultan, 2022. - from .eleven].

The claimed method is carried out on a well-known device described in RF patent No. 2748098 “Method for extracting high-viscosity oil and a device for its implementation” (Fig. 1).

The known device for implementing the claimed method consists of a lower tubing string 4, a lower heat-resistant packer 5n, an upper heat-resistant packer 5v, a support 6, a submersible pump 7, a bypass pipe 8, a tee 9, an upper tubing string 10, an additional pipe 12, a sealing element 13, perforated pipe for fluid selection 15, separation heat-resistant packer 16, specially built-in adjustable valve 17, injection perforated pipe 18. All components of the known device are interconnected by assembly operations, for example screwing. In this case, the lower heat-resistant packer 5n is connected to the injection perforated pipe 18; injection perforated pipe 18 is connected to the upper heat-resistant packer 5v; packer 5 in is connected to the lower tubing string 4 in such a way as to ensure fluid flow from support 6 into the injection perforated pipe 18; the lower tubing column 4 is connected to support 6; packer 5b is connected to a perforated fluid sampling pipe 15 in such a way as to ensure fluid flow through the hole in the support 6, in which a specially built-in adjustable valve 17 is installed; a separation heat-resistant packer 16 is installed on top of the perforated fluid sampling pipe 15; a submersible pump 7 is connected to a special built-in adjustable valve 17, while the submersible pump 7 on the other side is connected to the tee 9 in such a way as to make a connection with the sealing element 13; in this case, the sealing element 13 is further connected to an additional pipe 12 with the possibility of ensuring free passage of the produced fluid to the surface; in this case, a bypass pipe 8 is installed parallel to the submersible pump 7, which connects the support 6 with the tee 9 in such a way as to allow the flow of liquid from the upper tubing column 10 to the lower tubing column 4.

Next, the applicant provides a description of the claimed method (Fig. 1).

First, a device is assembled to implement the claimed method, similar to that described in RF patent No. 2748098 “Method for extracting high-viscosity oil and a device for its implementation,” namely: the well is lined with a casing pipe 1, which has the first and second opened zones 2 and 3 on a horizontal or inclined section, respectively , then the lower 5n and upper 5b heat-resistant packers are lowered into the well, connected to each other by a perforated injection pipe 18, the lower tubing string 4 is connected, on top of which a coaxially perforated fluid sampling pipe 15 is put on, then a separation heat-resistant packer 16 is installed, limiting the annulus 14, and screw the support 6 with a specially built-in adjustable valve 17 into the perforated fluid sampling pipe 15, connect the submersible pump 7 and insert a bypass pipe 8 into the support 6 on top, corresponding to the length of the submersible pump, install a tee 9 on the free end of the bypass pipe 8 and the outlet of the submersible pump 7, from the opposite side of which the upper tubing column 10 is screwed in and an additional pipe 12 with a sealing element 13 is inserted up to the tee 9 with an annular gap 11, at the end of which the tee 9 is attached.

Then the annular space between the casing and the upper string is filled with water, in the lower part the movement of water is limited by a heat-resistant separation packer and a built-in adjustable valve in the support.

Next, a pumping unit, for example, TsA-320 or SIN-50, pumps a calculated volume of BR (depending on the thickness of the productive formation and the depth (diameter) of treatment), containing 27.8 wt.% ammonium nitrate, 32.2 wt.% nitrite sodium, the rest is water, which is supplied through the annular gap, bypass pipe and lower column to the end section of the casing pipe. Next, the BR enters the productive formation through the first opened zone or the second opened zone and then it is forced from the tubing string into the bottomhole zone with an inert buffer fluid with a density higher than the density of the BR.

After carrying out the preparatory operations to start pumping, they start the downhole thermal activation of the exothermic chemical reaction of the injected BR (hereinafter referred to as thermal activation) - they begin to warm up the BR to the temperature of the beginning of the chemical reaction (plus 60-80 ° C) [“Test results of binary systems based on ammonium nitrate and sodium nitrite with new oxidation initiators", S.G. Uvarov, A.N. Beregovoy, N.A. Knyazeva, R.Sh. Ziatdinova, M.A. Rozova (TatNIPIneft), Collection of scientific works of TatNIPIneft, volume No. LXXXVII, PJSC Tatneft, 2019, pp. 132-136, UDC: 622.276.65-97, Publisher: ZAO Publishing House "Oil Industry" (Moscow)] . Next, a chain chemical reaction begins with the release of heat sufficient to form a thermal front throughout the entire treated zone of the formation, an increase in pressure and temperature appears, which are recorded by sensors, and heat spreads in the porous medium by reaction products.

Next, the thermal front heats up the high-viscosity oil in the formation, then the heated oil-water emulsion (fluid) with unreacted reaction products flows through the first opened zone into the annulus between the lower string and the initial section of the casing. Next, the heated oil-water emulsion enters through a built-in adjustable valve to receive a submersible pump and is pumped to the surface through an additional pipe.

When the flow rate decreases, pumping is stopped and the BR is reinjected into the productive zone of the formation through the lower column to increase oil fluidity, then pumping is carried out and the cycles are repeated.

In this case, thermal activation can be carried out in the following way:

downhole thermal activation of the exothermic chemical reaction of the injected BR is carried out by the method of simultaneously and separately injecting BR with an activator.

To do this, BR and activator are simultaneously and separately pumped into the mixing reactor in the ratio BR: activator = 1 m ³ : 0.02 m ³ , while an instant exothermic reaction occurs in the reactor with the release of hot gases and vapors, the temperature of which significantly exceeds the activation temperature previously pumped BR (for example, more than 60-80°C). The injection of BR with an activator ends with the launch of the chemical reaction of the BR, which is determined by the increase in pressure and temperature on installed control devices. The pressure and temperature are controlled, after the end of the reaction, the conversion of high-viscosity oil into fluid is maintained, after which they begin pumping to the surface with a submersible pump.

Next, the applicant provides an example of the implementation of the claimed technical solution (Fig. 1).

Example. Production of high-viscosity oil with in-well thermal activation of a binary solution using the method of simultaneously and separately injecting BR with an activator through a mixing reactor.

First, a device is assembled to implement the claimed method, similar to that described in RF patent No. 2748098 “Method for extracting high-viscosity oil and a device for its implementation,” namely: the well is lined with a casing pipe 1, which has the first and second opened zones 2 and 3 on a horizontal or inclined section, respectively , then the lower 5n and upper 5b heat-resistant packers are lowered into the well, connected to each other by a perforated injection pipe 18, the lower tubing string 4 is connected, on top of which a coaxially perforated fluid sampling pipe 15 is put on, then a separation heat-resistant packer 16 is installed, limiting the annulus 14, and screw the support 6 with a specially built-in adjustable valve 17 into the perforated fluid sampling pipe 15, connect the submersible pump 7 and insert a bypass pipe 8 into the support 6 on top, corresponding to the length of the submersible pump, install a tee 9 on the free end of the bypass pipe 8 and the outlet of the submersible pump 7, from the opposite side of which the upper tubing column 10 is screwed in and an additional pipe 12 with a sealing element 13 is inserted up to the tee 9 with an annular gap 11, at the end of which the tee 9 is attached.

Upon completion of installation of the device and activation of heat-resistant packers 5n, 5v and 16, which unite the annular space between the first and second opened zones 2 and 3, two hydraulic lines appear in the well. One line runs along the annular gap 11 between the additional pipe 12 and the upper tubing string 10, the bypass pipe 8 and the lower tubing string 4, ends with an injection perforated pipe 18 with a 5n packer at the end and exits to the second opened zone 3. The other line connects the first opened zone 2 annulus 14 between the lower tubing string 4, the perforated fluid sampling pipe 15 and the casing pipe 1 through a specially designed adjustable valve 17 and a submersible pump 7 with an additional pipe 12 that goes to the surface.

Next, the annular space between the casing 1 and the upper tubing string 10 is filled with technical or formation water; in the lower part, the movement of water is limited by a heat-resistant separation packer 16 and a specially built-in adjustable valve 17 in the support 6, which is necessary for cooling the engine of the submersible pump 7 when working with hot water. water-oil emulsion and to control the increase in pressure in the well.

Next, a BR is pumped from the surface containing 27.8 wt.% ammonium nitrate, 32.2 wt.% sodium nitrite, the rest is water (arrows with an open tip in Fig. 1), which (BR) along the annular gap 11, the bypass pipe 8 and the lower tubing string 4 are supplied to the end section of the casing pipe 1. The BR enters the productive formation through the opened zone 2 or 3 and is then pressed through with an inert buffer fluid.

Next, downhole thermal activation is started by the method of simultaneously and separately injecting the BR with the activator through a mixing reactor, in which an instant exothermic reaction occurs with the release of hot gases and vapors, the temperature of which significantly exceeds the activation temperature of the previously pumped BR (more than 60-80°C). Begin to heat the BR to the temperature at which the chemical reaction begins (for example, plus 70°C). Next, a chain chemical reaction begins with the release of heat sufficient to form a thermal front throughout the entire treated zone of the formation, an increase in pressure and temperature appears, which are recorded by sensors, and heat spreads in the porous medium by reaction products. Heating to a temperature above the activation temperature (for example, plus 70°C) stops when a stable increase in pressure and temperature appears on the installed control devices.

Next, the thermal front heats up the high-viscosity oil in the formation, then the heated oil-water emulsion with unreacted reaction products flows through the first opened zone 2 (arrows with a filled tip) into the annulus 14 between the lower tubing string 4 and the initial section of the casing 1. The heated oil-water emulsion enters through a specially built-in adjustable valve 17 to receive the submersible pump 7 and is pumped to the surface through an additional pipe 12. When the flow rate decreases, pumping is stopped and the BR is reinjected into the productive zone of the formation through the lower tubing string 4 to increase oil fluidity. This is followed by pumping out and the cycles are repeated.

The applicant explains that the scope of the patent claims is not limited to the presented method of heating BR, which is a special case of heating.

Thus, from the above we can conclude that the applicant has achieved the stated technical result, namely (see Fig. 2):

the ability to select the time from the start of BR injection to the start of the reaction through the use of special thermal initiation methods;

increased oil recovery due to the fact that when the flow rate decreases, BR is reinjected and the thermal heating method is used;

the ability to delay the start of the chemical impact of BR on the bottomhole zone for the required period, without fear of premature start of a chemical reaction due to the absence of an activator in the BR;

the ability to launch a chain reaction of heat transfer for sequential heating of the formation front.

The claimed technical solution meets the “novelty” criterion for inventions, since from the researched level of technology the applicant has not identified technical solutions that have the declared set of essential features.

The claimed technical solution meets the “inventive step” criterion for inventions, since no technical solutions have been identified that have features coinciding with the distinctive features of the claimed invention, and the influence of the distinctive features on the claimed technical result has not been established.

The claimed technical solution meets the “industrial applicability” criterion for inventions, since it can be manufactured on standard equipment using known materials and parts. It is impossible to control the quality of mixing of BS components with the activator due to the fact that mixing occurs directly in the well while moving along tubing trunk.

The invention is known according to patent RU No. 2778919 “Method for the production of high-viscosity oil and the thermo-gas-chemical composition for its implementation”, the essence is a thermo-gas-chemical composition for the production of high-viscosity oil, consisting of, wt.%: sodium nitrite - 27.8; ammonium nitrate - 32.2; copper sulfate - 0.12; water - the rest. A method for producing high-viscosity oil, which consists in first equipping a well, for which it is lined with a casing pipe that has first and second exposed zones in a horizontal or inclined section, then lower and upper heat-resistant packers are lowered into the well, connected to each other by an injection perforated pipe, connect the lower column, on top of which a coaxially perforated fluid sampling pipe is put on, then install a heat-resistant separation packer that limits the annulus space, and screw a support with a built-in adjustable valve into the perforated fluid sampling pipe, connect a submersible pump and insert a bypass pipe into the support from above, corresponding to the length of the submersible pump, a tee is mounted on the free end of the bypass pipe and the outlet of the submersible pump, on the opposite side of which the upper column is screwed and an additional pipe with an annular gap is inserted up to the tee with an annular gap, at the end of which the tee is attached; then the annular space between the casing pipe and the upper column is filled with water, in the lower part the movement of water is limited by a separation heat-resistant packer and a built-in adjustable valve in the support, then the thermogas-chemical composition is pumped according to claim 1, which is fed into the annular gap, bypass pipe and lower column the end section of the casing pipe, then the thermal gas chemical composition enters the productive formation through the first opened zone or the second opened zone and then it is pressed with light oil, the activation time of the exothermic chemical reaction and the heating time of high-viscosity oil in the formation are maintained, then the heated oil-water emulsion with unreacted reaction products drains through the first opened zone into the annulus between the lower column and the initial section of the casing, then the heated oil-water emulsion enters through a built-in adjustable valve to receive a submersible pump, the heated oil-water emulsion is pumped to the surface through an additional pipe; when the flow rate decreases, pumping is stopped and the thermogas-chemical composition is reinjected into the productive zone of the formation through the lower column to increase oil fluidity, then pumping is carried out and the cycles are repeated.

The disadvantages of the analogue in comparison with the declared technical solution are:

the impossibility of arbitrarily choosing the time from the start of BS injection to the start of the reaction due to the lack of special thermal initiation methods;

insufficient oil recovery due to the smaller coverage area of simultaneous heating;

the impossibility of delaying the onset of the chemical impact of BS on the bottomhole zone for the required period, the possibility of premature start of a chemical reaction due to the presence of an activator in the BS composition;

the impossibility of starting a chain reaction of heat transfer for sequential heating of the formation front - heat transfer is explosive.

The closest in terms of matching features, chosen by the applicant as a prototype, is the invention under patent RU 2363837 “Method and installation for thermo-gas-chemical influence on an oil reservoir and development of production and injection wells”, the essence is an installation for thermo-gas-chemical influence on an oil reservoir and development of production and injection wells wells, including a heat-resistant packer, a downhole steam and gas generator, an umbilical, an electric heater, pumping equipment and shut-off and control valves and containers for operational reserves and transportation of fuel and water, characterized in that it additionally contains a process monitoring and control station, forming together with the pumping equipment and shut-off and control valves, a unified system for monitoring and controlling the thermogas-chemical effect on the oil reservoir, the downhole steam and gas generator is made detachable and contains a stationary housing lowered on tubing and hermetically detachable connected to a heat-resistant packer, and a deep retrievable part lowered on an umbilical , containing an electric heater and remote thermometers for measuring the temperature in the combustion chamber of a downhole steam-gas generator and the temperature of the steam-gas mixture in the bottom-hole zone, the geophysical umbilical is made of polymer material and contains a hollow channel for supplying ignition fuel, electrical, power and signal channels, a tank for operational fuel reserve connected to the suction line of the pump for injection of fuel, the discharge line of which is connected to the internal cavity of the tubing, the tank for operational water reserve is connected to the suction line of the pump for injection of water, the discharge line of which is connected through a valve to the annulus of the well, the adjustable drive of the pump for injection of fuel is connected through a process monitoring and control station with a remote thermometer for measuring the temperature in the combustion chamber of a downhole steam-gas generator, the adjustable drive of the water injection pump is connected to a remote thermometer for measuring the temperature of the steam-gas mixture in the bottomhole zone to regulate the temperature at given points. A method of thermogas-chemical influence on an oil reservoir and the development of production and injection wells using the installation according to claim 1, including pumping fuel - an aqueous solution of urea and ammonium nitrate, initiating an exothermic reaction at the bottom of the well with a lowered electric heater, carrying out this reaction with its regulation in a downhole steam and gas generator the specified installation and development of the specified wells. The method according to claim 2, characterized in that the temperature of the reaction products is regulated in the direction of decreasing it by introducing additional water or urea solution into the fuel. The method according to claim 2, characterized in that the temperature of the reaction products is regulated in the direction of increasing it by introducing additional ammonium nitrate into the fuel. The method according to claim 2, characterized in that the level of hydrogen ions in the reaction products is increased by introducing an additional urea solution into the fuel. The method according to claim 2, characterized in that the level of hydrogen ions in the reaction products is reduced by introducing additional ammonium nitrate into the fuel. The method according to claim 2, characterized in that after steam-gas treatment with heating of the formation, a urea solution is pumped into it. The method according to claim 2, or 5, or 6, or 7, characterized in that in injection wells the vapor-gas rim created in the bottom-hole zone is advanced deeper into the formation by pumping water or an aqueous solution of urea. The method according to claim 8, characterized in that after steam-gas treatment with heating of the formation and its impregnation, the production well is developed. The method according to claim 2, characterized in that after steam-gas treatment with heating of the formation, high-temperature alkaline treatment of the formation in terrigenous rocks and acid treatment in carbonate rocks are carried out.

The disadvantages of the prototype compared to the stated technical solution are:

the impossibility of arbitrarily choosing the time from the start of BS injection to the start of the reaction due to the lack of special thermal initiation methods;

insufficient oil recovery due to the smaller coverage area of simultaneous heating;

the impossibility of delaying the onset of the chemical impact of BS on the bottomhole zone for the required period, the possibility of premature start of a chemical reaction due to the presence of an activator in the BS composition;

the impossibility of starting a chain reaction of heat transfer for sequential heating of the formation front - heat transfer is explosive.

The technical result of the claimed technical solution is to eliminate the shortcomings of the prototype, namely:

- the ability to select the time from the start of BR injection to the start of the initiation of an exothermic chain reaction through the use of simultaneously - separate injection of BR and activator;

increased oil recovery due to the fact that when the flow rate decreases, BR is reinjected and simultaneous separate injection of BR with an activator is used to heat up and begin to initiate an exothermic chain reaction;

the ability to delay the start of the chemical impact of BR on the bottomhole zone for the required period, without fear of premature start of a chemical reaction due to the absence of an activator in the BR;

the ability to launch a chain reaction of heat transfer for sequential heating of the formation front.

The essence of the claimed technical solution is a method for producing high-viscosity oil with in-well thermal activation of a binary solution, which consists in first equipping a well, for which it is lined with a casing pipe that has the first and second opened zones on a horizontal or inclined section, then the lower and second zones are lowered into the well. upper heat-resistant packers, interconnected by a perforated injection pipe, connect the lower column, on top of which a coaxially perforated fluid extraction pipe is put on, then install a separation heat-resistant packer that limits the interpipe space, and screw a support with a built-in adjustable valve into the perforated fluid extraction pipe, connect the submersible pump and a bypass pipe corresponding to the length of the submersible pump is inserted into the support from above, a tee is mounted on the free end of the bypass pipe and the outlet of the submersible pump, on the opposite side of which the upper column is screwed and an additional pipe with an annular gap is inserted up to the tee with an annular gap, at the end of which the tee is attached ; then the annular space between the casing and the upper column is filled with water, in the lower part the movement of water is limited by a separation heat-resistant packer and a built-in adjustable valve in the support, then a binary solution is pumped containing wt.% ammonium nitrate 27.8; sodium nitrite 32.2; water 40, which is supplied through the annular gap, bypass pipe and lower column to the end section of the casing, then the specified binary solution through the first opened zone or the second opened zone enters the productive formation and is then forced through an inert buffer liquid with a density higher than the density of the binary solution; Next, the downhole thermal activation of the exothermic chemical reaction of the injected binary solution is started by the method of simultaneously and separately injecting the specified binary solution and the activator - copper sulfate through a mixing reactor in the ratio, m ³ : binary solution: activator = 1: 0.02, while in the reactor - In the mixer, an instant exothermic reaction occurs with the release of hot gases and vapors, the temperature of which exceeds by more than 60°C the activation temperature of the previously pumped binary solution, the injection of the binary solution and activator ends with the launch of a chemical reaction of the binary solution, which is determined by the increase in pressure and temperature on installed devices control; then a chain chemical reaction begins with the release of heat sufficient to form a thermal front throughout the entire treated zone of the formation, an increase in pressure and temperature appears, which are recorded by sensors, heat spreads in the porous medium by reaction products; then the thermal front heats up the high-viscosity oil in the formation, then the resulting heated oil-water emulsion with reaction products flows through the first opened zone into the annulus between the lower string and the initial section of the casing, then it flows through the built-in adjustable valve to receive a submersible pump, then it is pumped out to surface along an additional pipe; when the flow rate decreases, pumping is stopped and the binary solution is reinjected into the productive zone of the formation through the lower column to increase oil fluidity, then pumping is carried out and the cycles are repeated.

The claimed technical solution is illustrated in Fig. 1 - Fig. 2.

In FIG. Figure 1 shows a device on which the claimed method is carried out, where 1 - casing pipe, 2 - first opened zone, 3 - second opened zone, 4 - lower tubing string, 5n - lower heat-resistant packer, 5v - upper heat-resistant packer, 6 - support, 7 - submersible pump discharge, 8 - bypass pipe, 9 - tee, 10 - upper column, 11 - annular gap, 12 - additional pipe, 13 - sealing element, 14 - annulus, 15 - perforated fluid extraction pipe, 16 - separation heat-resistant packer, 17 - specially built-in adjustable valve, 18 - perforated injection pipe.

In FIG. Figure 2 shows graphs of thermobaric parameters of the reaction of a binary solution at different concentrations of sodium nitrite and ammonium nitrate salts: 2a - reaction temperature of a binary solution at different concentrations of sodium nitrite and ammonium nitrate salts, 2b - reaction pressure of a binary solution at different concentrations of sodium nitrite and ammonium nitrate salts.

Next, the applicant provides a description of the claimed technical solution.

The claimed technical solution relates to a method for producing high-viscosity oil with in-well thermal activation of a binary solution and can be used in conditions of normal and low reservoir temperatures, to reduce oil viscosity, and can also be used in conditions of normal and low reservoir pressures, to increase the permeability of near-wellbore and remote zones productive formation by creating additional cracks and caverns. In addition to the above, the invention can be used to activate or renew oil wells, the productivity of which is reduced due to paraffin-hydrate and asphaltene-resin deposits contaminating filtration channels.

Below, the applicant provides information about the reagents used.

Sodium nitrite is a commercial product, for example, according to GOST 19906-74.

Ammonium nitrate (ammonium nitrate) is a commercial product, according to GOST 2-2013.

Next, the applicant provides a description of the preparation of the binary solution.

A binary solution (BS) for implementing the claimed method is prepared on the surface in a corrosion-resistant container and its quality and temperature are checked. A binary solution consists of an aqueous solution of two inorganic salts: sodium nitrite and ammonium nitrate.

Preparation of a binary solution

Take 27.8 wt.% (for example, 27.8 g) of ammonium nitrate, dissolve in 40 wt.% (for example, 40 g) of water distilled at a temperature of 20°C. The dissolution of ammonium nitrate occurs with decreasing temperature.

Next, 32.2 wt.% (for example, 32.2 g) of sodium nitrite is added to the cooled solution of ammonium nitrate and stirred until completely dissolved.

A binary solution is obtained containing 60 wt.% of active substances, of which 27.8 wt.% ammonium nitrate, 32.2 wt.% sodium nitrite, the rest is water. The selected ratio is optimal for starting the downhole thermal activation of an exothermic chemical reaction [“Binary compositions of delayed action for thermogas-chemical influence on the formation”, Andriyashin V.V., Milyutina V.A., Varfolomeev M.A. KMG Engineering LLP, Collection of abstracts of the International Scientific and Practical Conference “Prospects for the use of chemical methods of enhanced oil recovery (EOR) at the late stage of development”, September 16, 2022, Republic of Kazakhstan, Nur-Sultan, 2022. - from .eleven].

The claimed method is carried out on a well-known device described in RF patent No. 2748098 “Method for extracting high-viscosity oil and a device for its implementation” (Fig. 1).

The known device for implementing the claimed method consists of a lower tubing string 4, a lower heat-resistant packer 5n, an upper heat-resistant packer 5v, a support 6, a submersible pump 7, a bypass pipe 8, a tee 9, an upper tubing string 10, an additional pipe 12, a sealing element 13, perforated pipe for fluid selection 15, separation heat-resistant packer 16, specially built-in adjustable valve 17, injection perforated pipe 18. All components of the known device are interconnected by assembly operations, for example screwing. In this case, the lower heat-resistant packer 5n is connected to the injection perforated pipe 18; injection perforated pipe 18 is connected to the upper heat-resistant packer 5v; packer 5 in is connected to the lower tubing string 4 in such a way as to ensure fluid flow from support 6 into the injection perforated pipe 18; the lower tubing column 4 is connected to support 6; packer 5b is connected to a perforated fluid sampling pipe 15 in such a way as to ensure fluid flow through the hole in the support 6, in which a specially built-in adjustable valve 17 is installed; a separation heat-resistant packer 16 is installed on top of the perforated fluid sampling pipe 15; a submersible pump 7 is connected to a special built-in adjustable valve 17, while the submersible pump 7 on the other side is connected to the tee 9 in such a way as to make a connection with the sealing element 13; in this case, the sealing element 13 is further connected to an additional pipe 12 with the possibility of ensuring free passage of the produced fluid to the surface; in this case, a bypass pipe 8 is installed parallel to the submersible pump 7, which connects the support 6 with the tee 9 in such a way as to allow the flow of liquid from the upper tubing column 10 to the lower tubing column 4.

Next, the applicant provides a description of the claimed method (Fig. 1).

First, a device is assembled to implement the claimed method, similar to that described in RF patent No. 2748098 “Method for extracting high-viscosity oil and a device for its implementation,” namely: the well is lined with a casing pipe 1, which has the first and second opened zones 2 and 3 on a horizontal or inclined section, respectively , then the lower 5n and upper 5b heat-resistant packers are lowered into the well, connected to each other by a perforated injection pipe 18, the lower tubing string 4 is connected, on top of which a coaxially perforated fluid sampling pipe 15 is put on, then a separation heat-resistant packer 16 is installed, limiting the annulus 14, and screw the support 6 with a specially built-in adjustable valve 17 into the perforated fluid sampling pipe 15, connect the submersible pump 7 and insert a bypass pipe 8 into the support 6 on top, corresponding to the length of the submersible pump, install a tee 9 on the free end of the bypass pipe 8 and the outlet of the submersible pump 7, from the opposite side of which the upper tubing column 10 is screwed in and an additional pipe 12 with a sealing element 13 is inserted up to the tee 9 with an annular gap 11, at the end of which the tee 9 is attached.

Then the annular space between the casing and the upper string is filled with water, in the lower part the movement of water is limited by a heat-resistant separation packer and a built-in adjustable valve in the support.

Next, a pumping unit, for example, TsA-320 or SIN-50, pumps a calculated volume of BR (depending on the thickness of the productive formation and the depth (diameter) of treatment), containing 27.8 wt.% ammonium nitrate, 32.2 wt.% nitrite sodium, the rest is water, which is supplied through the annular gap, bypass pipe and lower column to the end section of the casing pipe. Next, the BR enters the productive formation through the first opened zone or the second opened zone and then it is forced from the tubing string into the bottomhole zone with an inert buffer fluid with a density higher than the density of the BR.

After carrying out the preparatory operations to start pumping, they start the downhole thermal activation of the exothermic chemical reaction of the injected BR (hereinafter referred to as thermal activation) - they begin to warm up the BR to the temperature of the beginning of the chemical reaction (plus 60-80 ° C) [“Test results of binary systems based on ammonium nitrate and sodium nitrite with new oxidation initiators", S.G. Uvarov, A.N. Beregovoy, N.A. Knyazeva, R.Sh. Ziatdinova, M.A. Rozova (TatNIPIneft), Collection of scientific works of TatNIPIneft, volume No. LXXXVII, PJSC Tatneft, 2019, pp. 132-136, UDC: 622.276.65-97, Publisher: ZAO Publishing House "Oil Industry" (Moscow)] . Next, a chain chemical reaction begins with the release of heat sufficient to form a thermal front throughout the entire treated zone of the formation, an increase in pressure and temperature appears, which are recorded by sensors, and heat spreads in the porous medium by reaction products.

Next, the thermal front heats up the high-viscosity oil in the formation, then the heated oil-water emulsion (fluid) with unreacted reaction products flows through the first opened zone into the annulus between the lower string and the initial section of the casing. Next, the heated oil-water emulsion enters through a built-in adjustable valve to receive a submersible pump and is pumped to the surface through an additional pipe.

When the flow rate decreases, pumping is stopped and the BR is reinjected into the productive zone of the formation through the lower column to increase oil fluidity, then pumping is carried out and the cycles are repeated.

In this case, thermal activation can be carried out in the following way:

downhole thermal activation of the exothermic chemical reaction of the injected BR is carried out by the method of simultaneously and separately injecting BR with an activator.

To do this, BR and activator are simultaneously and separately pumped into the mixing reactor in the ratio BR: activator = 1 m ³ : 0.02 m ³ , while an instant exothermic reaction occurs in the mixing reactor with the release of hot gases and vapors, the temperature of which is significantly higher activation temperature of the previously pumped BR (for example, more than 60-80°C). The injection of BR with an activator ends with the launch of the chemical reaction of the BR, which is determined by the increase in pressure and temperature on installed control devices. The pressure and temperature are controlled, after the end of the reaction, the conversion of high-viscosity oil into fluid is maintained, after which they begin pumping to the surface with a submersible pump.

Next, the applicant provides an example of the implementation of the claimed technical solution (Fig. 1).

Example. Production of high-viscosity oil with in-well thermal activation of a binary solution using the method of simultaneously and separately injecting BR with an activator through a mixing reactor.

First, a device is assembled to implement the claimed method, similar to that described in RF patent No. 2748098 “Method for extracting high-viscosity oil and a device for its implementation,” namely: the well is lined with a casing pipe 1, which has the first and second opened zones 2 and 3 on a horizontal or inclined section, respectively , then the lower 5n and upper 5b heat-resistant packers are lowered into the well, connected to each other by a perforated injection pipe 18, the lower tubing string 4 is connected, on top of which a coaxially perforated fluid sampling pipe 15 is put on, then a separation heat-resistant packer 16 is installed, limiting the annulus 14, and screw the support 6 with a specially built-in adjustable valve 17 into the perforated fluid sampling pipe 15, connect the submersible pump 7 and insert a bypass pipe 8 into the support 6 on top, corresponding to the length of the submersible pump, install a tee 9 on the free end of the bypass pipe 8 and the outlet of the submersible pump 7, from the opposite side of which the upper tubing column 10 is screwed in and an additional pipe 12 with a sealing element 13 is inserted up to the tee 9 with an annular gap 11, at the end of which the tee 9 is attached.

Upon completion of installation of the device and activation of heat-resistant packers 5n, 5v and 16, which unite the annular space between the first and second opened zones 2 and 3, two hydraulic lines appear in the well. One line runs along the annular gap 11 between the additional pipe 12 and the upper tubing string 10, the bypass pipe 8 and the lower tubing string 4, ends with an injection perforated pipe 18 with a 5n packer at the end and exits to the second opened zone 3. The other line connects the first opened zone 2 annulus 14 between the lower tubing string 4, the perforated fluid sampling pipe 15 and the casing pipe 1 through a specially designed adjustable valve 17 and a submersible pump 7 with an additional pipe 12 that goes to the surface.

Next, the annular space between the casing 1 and the upper tubing string 10 is filled with technical or formation water; in the lower part, the movement of water is limited by a heat-resistant separation packer 16 and a specially built-in adjustable valve 17 in the support 6, which is necessary for cooling the engine of the submersible pump 7 when working with hot water. water-oil emulsion and to control the increase in pressure in the well.

Next, a BR is pumped from the surface containing 27.8 wt.% ammonium nitrate, 32.2 wt.% sodium nitrite, the rest is water (arrows with an open tip in Fig. 1), which (BR) along the annular gap 11, the bypass pipe 8 and the lower tubing string 4 are supplied to the end section of the casing pipe 1. The BR enters the productive formation through the opened zone 2 or 3 and is then pressed through with an inert buffer fluid.

Next, downhole thermal activation is started by the method of simultaneously and separately injecting the BR with the activator through a mixing reactor, in which an instant exothermic reaction occurs with the release of hot gases and vapors, the temperature of which significantly exceeds the activation temperature of the previously pumped BR (more than 60-80°C). Begin to heat the BR to the temperature at which the chemical reaction begins (for example, plus 70°C). Next, a chain chemical reaction begins with the release of heat sufficient to form a thermal front throughout the entire treated zone of the formation, an increase in pressure and temperature appears, which are recorded by sensors, and heat spreads in the porous medium by reaction products. Heating to a temperature above the activation temperature (for example, plus 70°C) stops when a stable increase in pressure and temperature appears on the installed control devices.

Next, the thermal front heats up the high-viscosity oil in the formation, then the heated oil-water emulsion with unreacted reaction products flows through the first opened zone 2 (arrows with a filled tip) into the annulus 14 between the lower tubing string 4 and the initial section of the casing 1. The heated oil-water emulsion enters through a specially built-in adjustable valve 17 to receive the submersible pump 7 and is pumped to the surface through an additional pipe 12. When the flow rate decreases, pumping is stopped and the BR is reinjected into the productive zone of the formation through the lower tubing string 4 to increase oil fluidity. This is followed by pumping out and the cycles are repeated.

Thus, from the above we can conclude that the applicant has achieved the stated technical result, namely (see Fig. 2):

the ability to select the time from the start of BR injection to the start of the reaction through the use of special thermal initiation methods;

increased oil recovery due to the fact that when the flow rate decreases, BR is reinjected and the thermal heating method is used;

the ability to delay the start of the chemical impact of BR on the bottomhole zone for the required period, without fear of premature start of a chemical reaction due to the absence of an activator in the BR;

the ability to launch a chain reaction of heat transfer for sequential heating of the formation front.

The claimed technical solution meets the “novelty” criterion for inventions, since from the researched level of technology the applicant has not identified technical solutions that have the declared set of essential features.

The claimed technical solution meets the “inventive step” criterion for inventions, since no technical solutions have been identified that have features coinciding with the distinctive features of the claimed invention, and the influence of the distinctive features on the claimed technical result has not been established.

The claimed technical solution meets the “industrial applicability” criterion for inventions, since it can be manufactured on standard equipment using known materials and parts.

Claims (7)

A method for producing high-viscosity oil with in-well thermal activation of a binary solution, which consists in the following: First, they equip the well, for which they line it with a casing pipe, which has the first and second opened zones in a horizontal or inclined section, then lower and upper heat-resistant packers are lowered into the well, connected to each other by an injection perforated pipe, connect the lower column, on top of which a coaxially perforated pipe is put on fluid selection, then install a separation heat-resistant packer that limits the interpipe space, and screw the support with a built-in adjustable valve into the perforated fluid selection pipe, connect the submersible pump and insert a bypass pipe from above into the support, corresponding to the length of the submersible pump, onto the free end of the bypass pipe and discharge the submersible a tee is mounted on the pump, on the opposite side of which the upper column is screwed and an additional pipe with a sealing element is inserted up to the tee with an annular gap, at the end of which the tee is attached; then the annular space between the casing and the upper column is filled with water, in the lower part the movement of water is limited by a heat-resistant separation packer and a built-in adjustable valve in the support, Next, a binary solution is pumped containing, wt.%: ammonium nitrate 27.8; sodium nitrite 32.2; water 40, which is supplied through the annular gap, bypass pipe and lower column to the end section of the casing pipe, then the specified binary solution through the first opened zone or the second opened zone enters the productive formation and is then pressed with light oil with a density of no more than 0.92 g /cm ³ ; Next, the downhole thermal activation of the exothermic chemical reaction of the injected binary solution is started by the method of simultaneously and separately injecting the specified binary solution and the activator - copper sulfate through a mixing reactor in the ratio, m ³ : binary solution: activator - copper sulfate = 1:0.02, while in the mixing reactor, an instant exothermic reaction occurs with the release of hot gases and vapors, the temperature of which exceeds the activation temperature of the previously pumped binary solution by more than 60°C; the injection of the binary solution and the copper sulfate activator ends with the launch of a chemical reaction of the binary solution, which is determined by the increase in pressure and temperatures on installed control devices; then a chain chemical reaction begins with the release of heat sufficient to form a thermal front throughout the entire treated zone of the formation, an increase in pressure and temperature appears, which are recorded by sensors, heat spreads in the porous medium by reaction products; then the thermal front heats up the high-viscosity oil in the formation, then the resulting heated oil-water emulsion with reaction products flows through the first opened zone into the annulus between the lower column and the initial section of the casing, then it flows through a built-in adjustable valve to receive a submersible pump, then it is pumped out to surface along an additional pipe; when the flow rate decreases, pumping is stopped and the binary solution is reinjected into the productive zone of the formation through the lower column to increase oil fluidity, then pumping is carried out and the cycles are repeated.