RU2569375C1 - Method and device for heating producing oil-bearing formation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method for heating producing oil-bearing formation includes delivery of water pre-heated by the heater placed at the surface under pressure through injecting well. The device for heating producing oil-bearing formation comprises a pump with drive, which input is connected to water tank and through the heater to the injecting well. At that a nuclear reactor is used as the source of thermal energy. In the bottomhole there is a heat exchanger, to which circulation loop with heat carrier of the nuclear reactor is connected through two flexible coil tubings. Upon heating at the surface water is heated additionally within the whole length of the well and in the bottomhole.

EFFECT: improved efficiency of the process.

5 cl, 3 dwg

Description

The invention relates to the oil industry and can be used in the development of viscous oil, paraffin oil, bitumen, oil and kerogens from sand and clay rocks of oil-containing deposits. It is also possible to produce oil and gas in offshore fields and in permafrost and for the production of gas hydrates.

Highly viscous and heavy oil are included in the category of hard-to-recover reserves, which today account for about 36% of the total oil production in the Russian Federation, and experts predict that by 2020 this figure will increase to 77% of all production. To produce one ton of highly viscous or heavy oil, it is necessary to put into development two to five times more hard-to-recover reserves and to drill two to five times more wells in comparison with active reserves. The extraction coefficient of high viscosity and heavy oil, as a rule, is 2-3 times lower than the recovery ratio of oil related to active reserves.

Another, no less significant challenge for the Russian oil industry is the organization of industrial oil production from the Bazhenov formation. The Bazhenov Formation is represented by the source rock, in which the processes of conversion of kerogen to hydrocarbons have not yet been completed. Highly saturated clay deposits of the Bazhenov Formation are almost ubiquitous within the West Siberian Lowland over an area of more than 1 million square kilometers. The total geological oil reserves in them are estimated at between 0.8 and 2.1 trillion tons, and the growth potential of recoverable oil reserves is estimated at no less than 30-40 billion tons. The depth of the Bazhenov Formation is 2500-3000 meters. The thickness of the layer is 10-40 meters. The temperature of the reservoir is 80-130 degrees Celsius. Due to the fact that the rock of the Bazhenov formation has complex capacitive and filtration properties, the coefficient of oil recovery from the Bazhenov formation during its development by traditional methods does not exceed 3-5 percent.

The most common ways to increase the production of high-viscosity and heavy oil are thermal steam and gas technologies.

During heat treatment of an oil-containing formation by steam, oil viscosity decreases under the influence of heat, thermal expansion of oil, actualization of the gas-pressure regime, increase in mobility and phase permeability of oil and water, as well as in-situ distillation of residual oil by steam.

Compared to simple thermal steam technology, thermal steam-gas technology seems to be more effective, since the presence of mainly flue gases and, in particular, carbon dioxide in a gas-vapor mixture has a positive effect on the oil displacement coefficient, increases the permeability of the reservoir, prevents clay swelling, additionally reduces the viscosity of oil, and also lowers the oil-water and steam-oil factors.

The use of thermal vapor-gas technology involves the use of ground-based complexes for generating a gas-vapor mixture or downhole generators of a gas-vapor mixture.

A well-known downhole steam and gas generator developed by RITEK, generating a steam-gas mixture directly at the bottom and containing channels for introducing air, fuel mixture and water, a fuel nozzle, an ignition unit and a combustion chamber with an outlet nozzle, while the steam and gas generator is additionally equipped with a pre-chamber and an evaporation chamber, the inner surface of which is made narrowing devices with sectors of water discharge, and the combustion chamber is made in the form of two coaxially located shells with the possibility of moving the relative but each other and the formation of a cooling jacket, and on the outer surface of the inner shell of the combustion chamber a multi-start screw is made (RF patent No. 2316648, IPC ЕВВ 43/24, 2008 publication).

The well-known steam and gas generator is capable of generating from 1 to 4 tons of gas mixture per hour. The maximum temperature generated by the known device gas-vapor mixture (working agent) is 350 ° C. The maximum pressure developed by the known device at the bottom is not more than 20 MPa. The known device uses mono-fuel, which is a solution of ammonium nitrate with the addition of hydrogen-containing components. To burn mono-fuel, the thermolysis process is used - burning mono-fuel at high temperature without the participation of a catalyst. To initiate the process of thermolysis in the combustion chamber of a known device requires mandatory preheating of monofuel for 5-6 minutes to a temperature of 350 ° C in the chamber of the known device.

The disadvantages of the well-known downhole steam and gas generator developed by RITEK are:

- a relatively low temperature of the generated vapor-gas mixture, sufficient so that the known device could be used to increase the production of highly viscous and heavy oil, but insufficient to maintain the efficient processes of in-situ thermal cracking and in-situ pyrolysis to extract oil from kerogen-containing rocks, for example, the Bazhenov formation ;

- the relatively low pressure of the vapor-gas mixture generated by the known device, sufficient so that the known device could be used to increase the production of highly viscous or heavy oil, lying mainly at depths from 1000 to 1500 meters, but insufficient to extract oil from kerogen-containing rocks Bazhenov Formation, the strata of which are characterized by abnormally high reservoir pressure up to 40-45 MPa;

- the relatively low productivity of the known device compared to ground-based gas-generating plants and the difficulty of increasing the productivity of the known device due to the impossibility of increasing the overall dimensions of the most famous device at the bottom, the volume of the combustion chamber of the known device and the fact that the fuel mixture is burned in the combustion chamber of the known device open flame. The performance of the known device is determined mainly by the volume of the combustion chamber of the known device and the amount of fuel mixture supplied per minute to the combustion chamber of the known device. In the case of increasing the amount of the supplied fuel mixture per minute into the combustion chamber of the known device, the stability of the process of flaring the fuel mixture will decrease until the process of flaring fuel is stopped;

- the use of a known device only special monofuel (liquid fuel mixture) and the inability to use other liquid fuel mixtures or gaseous fuel mixtures based on methane;

- the need for mandatory pre-heating of monofuel to a temperature of 350 ° C before it is fed into the combustion chamber of a known device;

- the inability to enrich the gas-vapor mixture generated by the known device, additional components, such as nitrogen, carbon dioxide, hydrogen and other gases;

- generation by a known device of a gas-vapor mixture with an unchanged content in the gas-vapor mixture of only water and flue gases resulting from the combustion of monofuel;

- in the composition of the gas-vapor mixture generated by the known device, there is soot, which is formed during the flaring of monofuel and the presence of which is undesirable in the gas-vapor treatment of oil-containing and kerogen-containing formations.

Catalytic heat generators are known (RF patents №2124674, 2232942, 2380612), which use the principle of catalytic flameless oxidation of liquid and gaseous fuels or fuel mixtures related to heat energy for heat generation, and which can be used in industry, agriculture, housing and communal services , in transport and other areas for autonomous water heating of air heating, as well as hot water supply for residential and industrial premises, buildings and structures.

Despite all the advantages of these specific devices related to the power system and designed to generate heat, the well-known catalytic heat generators cannot be directly used to generate gas-vapor or vapor-gas-catalytic mixture at the bottom of the well for the following main reasons:

- overall dimensions and design features of the known devices do not allow their use in the bottom of the well;

- the design of the catalytic reactors of known devices are not intended to generate a gas-vapor mixture directly in the catalytic reactors of the devices and in direct contact of the catalyst with the fuel mixture. The heat generated as a result of the catalytic oxidation reaction of fuel in known devices occurs due to the use of various kinds of heat exchange surfaces or heat exchangers placed in catalytic reactors of known devices;

- designs of known devices do not provide for the possibility of additional enrichment of products of catalytic flameless combustion of fuel or fuel mixtures with water, gases and nanosized catalyst particles;

- the designs of catalytic reactors of known devices and the types of catalysts used in catalytic reactors of known devices involve minimizing the emission of carbon dioxide and nitrogen oxides, while the process of catalytic flameless combustion of liquid or gaseous fuel mixtures in the inventive downhole catalytic generator of a vapor-gas-catalytic mixture assumes, on the contrary, their maximization in the composition of catalytic combustion products.

There is also known a method of thermochemical exposure of a porous medium, according to which metal particles are pumped into the reservoir with water, through which, in turn, a reagent is pumped - alkali or acid. As a result of a chemical exothermic reaction, the productive formation is heated, to control the temperature of which subsequently flow-control reagents are pumped into the reservoir (patent of the Russian Federation No. 2399752, E21B 43/24, publication 2010).

The disadvantages of this method is the following:

- the method involves the injection into the reservoir of large volumes of water, which, of course, leads to excessive flooding of the reservoir;

- the method for generating in-situ exothermic chemical reactions involves the use of alkalis and acids, which complicates and increases the cost of heat treatment of the reservoir;

- the method cannot be used to extract oil from kerogen, since the working temperature of the known method (200 degrees Celsius) is not high enough for this;

- the method also has a very complex algorithm for heat treatment of the reservoir, which consists in the sequential implementation of three separate operations: (a) pumping water with metal particles, (b) pumping the reagent and (c) pumping the flow control reagents;

- the method involves the injection into the reservoir of a large amount of cold water and cold flow control agents that lower the temperature of the reservoir, which reduces the effectiveness of thermochemical effects on the porous medium.

An analogue of the claimed invention is a method of treating a formation, including descent into a well of a heater, supplying a gas-air mixture, supplying heat of combusted gases to the formation, while a catalytic furnace is lowered into the well as a heater, the catalyst is heated to the temperature of the catalytic combustion of the mixture, and the gas-air mixture is supplied with the content methane from 2.35-4.89 and from 16-64.5 volume percent (RF application for invention No. 2004121821, E21B 43/24, publication 2006).

The disadvantages of this method include:

- the product of catalytic combustion in a catalytic furnace gas-air mixture is a high-temperature gas-air mixture, which contains a small amount of flue gases. It is known from the state of the art that flue gases (carbon dioxide and nitrogen oxides) favor enhanced oil recovery of oil-containing and / or kerogen-containing formations. When a large amount of carbon dioxide and nitrogen oxides enters the formation, the oil displacement coefficient increases, the permeability of the reservoir increases, the viscosity of the oil decreases, the water-oil and vapor-oil factors decrease, while the presence of the above gases and their oxides in oil-containing and / or kerogen-containing formations prevents clay swelling, which is especially important for collectors with a high percentage of clay, for example, collectors of the Bazhenov Formation. Therefore, the low content of flue gases in the product of catalytic combustion of the known device cannot lead to a significant increase in oil recovery of oil-containing and / or kerogen-containing formations and this is the first disadvantage of the known device;

Acceptable temperatures for impacting a rock (e.g., sandstone) in the near-wellbore space are temperatures from 400 to 800 degrees Celsius, at which the process of peeling of the rock is actively developing and the macro- and microcracking of the reservoir is growing. To obtain such temperatures in the zone of an oil-containing or kerogen-containing formation, the known device must be located in the well above and at a distance of at least 800-1000 meters from the oil-containing or kerogen-containing formation. In this case, due to heat losses, the temperature in the zone of the oil-containing and / or kerogen-containing formation will drop to 700-800 degrees Celsius.

A known method and device for the development of hard-to-reach oil and a downhole gas generator according to the patent of the Russian Federation for invention No. 2447276, IPC E21B 43/24, publ. 04/10/2012

This method involves the formation of a working agent and its supply under pressure to an oil-containing one through an injection well, while the vapor-gas-catalytic mixture formed during the combustion of a liquid or gaseous carbon-containing fuel mixture in a catalytic reactor due to the exothermic reaction of a catalytic flameless oxidation of liquid or gaseous carbon-containing fuel mixtures and the subsequent mixing of the obtained product with a concentration mixture containing catalysis torus to provide in-situ thermocouple gas-catalytic effects on the reservoir, potassium permanganate dissolved in water was used as a catalyst. The liquid fuel mixture preferably consists of water, methanol and hydrogen peroxide, while a gaseous mixture comprising carbon dioxide and nitrogen is used as an enrichment mixture to obtain a working agent.

This device is made in the form of tanks of fuel and concentration mixture, connected by means of coiled tubing to a downhole gas generator installed in the casing of the injection well and containing a housing, fuel and concentration mixture channels, a combustion chamber and an exit nozzle, which the nozzle is made narrowing. The liquid fuel mixture preferably consists of water, methanol and hydrogen peroxide, while a gaseous mixture comprising carbon dioxide and nitrogen is used as an enrichment mixture to obtain a working agent

The downhole gas generator comprises a combustion chamber and a nozzle.

Disadvantages - the high cost of equipment in which noble metals are used as a catalyst: gold and platinum. In addition, the catalyst placed in the downhole gas generator during operation is covered with a layer of carbon due to incomplete combustion of fuel. The use of nanoparticles only worsens the situation, since carbon is more precipitated between them. All this reduces the effectiveness of retorting the oil reservoir.

The known method and device for heating the reservoir according to the patent of the Russian Federation No. 2377402, IPC E21B 43/24, publ. 27.12. 2009 year

This method involves the injection of water heated in a heater located in the exhaust device of the gas pumping unit and its injection into the reservoir.

This device contains a pump with a drive, the inlet of which is connected to a water tank, and the outlet to an injection well. According to the invention, the device has a gas pumping unit comprising a gas turbine engine and a free turbine, a natural gas gas line, a fuel line connected to a gas line to supply fuel to the gas turbine, a compressor for pumping natural gas and increasing pressure in the gas line, and a heat exchanger. This heat exchanger is installed along the water line after the pump in the exhaust device of the gas pumping unit. An exhaust device is installed behind a free turbine. The rotor of a free turbine is connected to a compressor for pumping gas.

Disadvantages - the relatively low energy efficiency of the method and device, due to the fact that due to heat transfer in the casing of the injection well, the water temperature decreases by about 100 ° C per kilometer of depth. With a depth of more than 3 km in the reservoir, more than 70% of the energy does not reach the reservoir.

The objectives of the invention, consistent with the technical result, is to increase the efficiency of the process.

The solution of these problems was achieved in a method of heating a productive oil reservoir, including the supply of pre-heated water in a heater placed on the surface under pressure through an injection well, characterized in that the heater works from a nuclear reactor, after heating on the surface, water is additionally heated along the entire length of the well and in the face. A nuclear reactor is used to heat water in the injection well and heat exchangers of several wells in the field. Heating is performed within 1-500 days.

The solution of these problems was achieved in a device for heating a productive oil reservoir containing a pump with a drive, the input of which is connected to a water tank, and the output through a heater with an injection well, characterized in that a nuclear reactor is used as a source of thermal energy for the heater, a heat exchanger is installed to the bottom of the well, to which a coolant circuit of a nuclear reactor is connected using two flexible piping of the tubing. The heater may be connected by water supply pipelines to several injection wells of the field, and the nuclear reactor may be connected by coolant circulation pipelines to several injection wells of the field.

The invention is illustrated in the drawings (Fig. 1 ... 3), where:

in FIG. 1 is a diagram of a device,

in FIG. 2 shows a diagram of a device with two injection and two production wells,

in FIG. 3 shows a diagram with three or more injection wells.

A device for heating a productive oil-containing formation contains an injection well 1, in which a casing 2 is installed, having vertical and horizontal sections 3 and 4, respectively. Perforation 5 was performed on the entire horizontal section 4. In the upper part of the casing 2 at the mouth, i.e. above the surface 7 of the rock 8, the collector is made 9. The horizontal section 5 is made within the reservoir 10.

The device has the following equipment installed on surface 7 (Fig. 1): a water tank 11, a water pipe 12, a valve 13, a water pump 14, a water heater 15. Heat is supplied to the water heater 15 from a nuclear reactor 16, which is recycled through coolant pipelines 17 and 18 is connected to the water heater 15. The recirculation pipe of the coolant 17 contains a pump 19. The outlet of the heater 15 by a pipe 20 is connected to the manifold 9 and then to the casing 2 of the injection well 1.

The system for additional heating of water in the well comprises a coolant supply system and a coolant return system. The coolant supply system includes a coolant pipe 21, a pump 22 and a first coiled tubing 23 with a flexible pipe 24, which is lowered from the injection well 1 and connected to a heat exchanger 25 installed therein. The coolant return system comprises a return pipe 26 connected to the nuclear reactor 16, with a valve 27, a second coiled tubing 28 and a flexible conduit 29 extending in the casing and connected to the heat exchanger 25.

Oil is extracted from the producing well 30 using a production casing 31, at the mouth of which there is a manifold 32, to which the inlet of the pump 34 is connected by a pipe 33. The outlet of the pump 34 through the cleaning device 35 is connected to the oil pipe 36.

In FIG. 2 shows a similar device using two injection wells, and FIG. 3 - using three or more wells. One heater 15 and one nuclear reactor 16 are used for any number of injection wells.

DEVICE OPERATION

When working in a water tank, water is charged from a reservoir or water supply system.

After that, the nuclear reactor 16 is started and the valves 13, 23 and 27 are opened and the heated water is supplied from the water tank 11 through the pipe 12 through the valve 13 and the pump 14 to the water heater 15 and then through the pipe 20 to the casing manifold 9.

At the same time, from the nuclear reactor 16, the coolant is pumped through the circulation pipe 17 to the water heater 15 by the pump 18 and, having cooled, is returned to the nuclear reactor 16 through the circulation pipe 18. The heated water enters the collector 9 and then into the casing 2, where, as it moves towards the bottom cooled by 100 ... 300 ° C.

To prevent this, the coolant through flexible pipes 24 and 29 circulates through the heat exchanger 25, while heating water not only in the area of installation of the heat exchanger 29, but also in the casing 2 itself, partially or completely compensating for the cooling of hot water in it.

There is a heating of the soil 8 in the reservoir 9: heating of viscous oil and evaporation of light oil fractions.

Oil is extracted from the production well 30 of the production casing 31 using a pump 34. After cleaning and separation in the cleaning device 35, the oil is transferred to the oil pipeline 36 and then to the consumer.

The use of a group of inventions allowed:

1. To bring the maximum possible amount of energy into the heating well, while spending a minimum of economic costs on this energy.

2. At the development site using the proposed method, oil recovery of 75% is achieved. Thus, the optimal value of the ratio of the components of the fuel and water-fuel ratio allowed to obtain greater oil recovery compared to the prototype. The method allows to extract hard to recover oil products: bitumen, shale oil and kerogen-containing oil, by heating the oil reservoir to relatively high temperatures.

3. To reduce the heating time of the oil reservoir to 250 ° C in 20 ... 30 times compared with the prototype.

Claims (5)

1. A method of heating a productive oil reservoir, including the supply of pre-heated in a heater located on the surface, pressurized water through an injection well, characterized in that the heater works from a nuclear reactor, after heating on the surface, water is additionally heated along the entire length of the well and in the bottom hole . 2. The method according to p. 1, characterized in that the nuclear reactor is used to heat water in the injection well and heat exchangers of several wells of the field. 3. The method according to p. 1 or 2, characterized in that the heating is performed within 1-500 days. 4. A device for heating a productive oil reservoir containing a pump with a drive, the input of which is connected to a water tank, and the output through a heater with an injection well, characterized in that a nuclear reactor is used as a source of thermal energy for the heater; a heat exchanger to which, with the help of two flexible pipelines, is connected to the circulation loop of the coolant of a nuclear reactor. 5. The device according to p. 4, characterized in that the heater is connected by water supply pipelines to several injection wells of the field, and the nuclear reactor is connected by coolant circulation pipelines to several injection wells of the field.

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