RU2567583C1 - Method of viscous oil development, device for its implementation and bottomhole gas generator - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method of development of viscous oil fields includes creation in the formation of the zone of formation oxidating and thermodynamic processes by insertion in the horizontal part of the casing in the injection well of the bottomhole gas generator, and by fuel component ignition in it: fuel with oxidant, and admixture to the combustion products of the pre-heated water. At that the fuel, oxidant and heated water are injected though several coiled tubings in the bottomhole gas generator. Water by the water pump is injected in the water heater installed upstream the coiled tubing. The fuel components are ignited in the bottomhole gas generator using the ignition plug, and the bottomhole gas generator is slowly moved using the synchronous operation of the coiled tubings along the entire horizontal part of the casing towards wellhead. Then the bottomhole gas generator is removed from the heating well. Tubing string with the well filters in the horizontal part of the casing is run in it, and production of the liquid phase, gas fractions and light evaporated oil products are produced, separated and cleaned.

EFFECT: increased process efficiency and safety assurance.

18 cl, 19 dwg, 2 tbl

Description

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

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 ° C. Due to the fact that the Bazhenov formation rock has complex capacitive and filtration properties, the oil recovery factor from the Bazhenov formation during its development by traditional methods does not exceed 3-5%. With the use of new technologies theoretically reaches 49%.

There is a method of developing an oil deposit by injecting an oxygen-containing mixture into the formation, in which, to increase the efficiency of oil recovery and the safety of work, a coolant is pumped into the bottom-hole zone of the injection well with a temperature and volume that ensures the full consumption of the oxidizing agent at the process initiation stage (A. St. USSR No. 1090060 )

This method guarantees the safety of the process only at the stage of its initiation. When a heat wave moves through a formation under low-viscosity oil conditions and the fuel deficit associated with this circumstance, oxygen can penetrate into unheated sections of the formation, up to the trunks of production wells. All this provokes an explosive situation at the development site.

In addition, in all known development methods, the natural energy of the field is not taken into account when choosing the object of influence, and at the stage of the initiation of the process, it is assumed that the thermodynamics of the bottom-hole zone are changed by introducing energy from the outside (from the surface), which does not contribute to the achievement of the maximum possible oil recovery and significantly worsens the cost-effectiveness ways.

A known method of developing an oil field according to the patent of the Russian Federation for the invention No. 2139421, IPC publ. 2010, in which, in order to increase oil recovery of light oil fields, it is planned to use thermogas treatment.

According to the known method, the essence of thermogas exposure is that an oxygen-containing mixture is pumped into the formation through an injection well - air, which, as a result of spontaneous in-situ oxidation processes, is transformed into a highly effective displacing agent, partially or completely mixed with the displaced oil. Such a transformation is ensured both due to the formation of CO ₂ as a result of in-situ oxidation processes, and due to the transition of light fractions into the gas phase under the influence of thermal energy released as a result of in-situ oxidation processes. An important criterion for the implementation of thermogas exposure is the level of the initial reservoir temperature, which according to the above method should exceed 65 ° C. The need to comply with this condition is determined by the fact that the intensity of spontaneous in-situ oxidation processes ensures almost complete consumption of oxygen injected into the formation in the zone, the dimensions of which are several times less than the distance between the wells. This means that the injection of an oxygen-containing mixture provides not only the in-situ formation of a displacing agent miscible with the displaced oil, but also the safety of the process.

Thus, the conditions provided for by the known method for the implementation of the thermogas development method make it possible to ensure high efficiency of displacing light oil from the covered drained zones of oil-bearing rocks.

However, according to the non-trivial features of the filtration-capacitive properties of the rocks of the Bazhenov formation and the hydrocarbon content in them, the traditional approach to the formation of a development system with any method of exposure cannot provide effective oil recovery. In this regard, it should first of all be pointed out to the extremely wide range of filtration-capacitive characteristics of lithotypes of rocks of the Bazhenov formation noted above, the unevenness of their development both laterally and vertically. The consequence of such heterogeneity of the reservoir properties of the rocks of the Bazhenov formation is the uneven distribution of drainage zones, often the unpredictable nature of their hydrodynamic connection.

It can be assumed that such a non-trivial nature of the reservoir of the Bazhenov formation is one of the main reasons for the unsatisfactory performance of the fields of the Bazhenov formation in the previous three decades. That is why traditional waterflooding is also assessed as an unpromising way to develop such deposits.

In this regard, it should be noted the important feature of the Bazhenov formation deposits noted above, according to which the light oil contained in the matrix (microcracked part of the rocks) can hardly be extracted using traditional development methods (natural mode, water flooding). It is also obvious that these methods cannot involve hydrocarbon resources of organic matter - kerogen.

The technology of the thermogas method for developing light oil fields with conventional reservoirs according to the aforementioned method provides for the formation of an effective displacing agent miscible with oil in the formation due to spontaneous in-situ oxidation processes when air is injected into the formation. Therefore, the main criterion for the implementation of this technology is the initial reservoir temperature, the level of which should be above 65 ° C.

Field domestic and international experience has confirmed that the injection of air into such reservoirs actually leads to the formation of an effective displacing agent in the reservoir, which ensures oil recovery up to 60% and higher in fields with low permeability reservoirs.

Obviously, the implementation of thermogas exposure in the fields of the Bazhenov formation can also increase the efficiency of oil recovery from drained zones. However, according to the above, this is not enough, because for the effective development of deposits of the Bazhenov formation it is necessary to provide the solution of the following problems:

- to ensure the maximum possible extraction of light oil from the non-drained matrix, as well as hydrocarbons from kerogen, contained in both non-drained and drained rocks;

- to ensure the maximum possible development of the drainage zone not only in the matrix, but also in macrocrack rocks;

- to ensure effective displacement of light oil from drained areas.

To solve these problems, the technology of thermogas impact on the rocks of the Bazhenov formation should be characterized by the following parameters:

- in-situ oxidation processes should ensure the formation in the drained lithotypes of rocks moving zones of heat generation;

- the dimensions of the heat generation zone, the speed of its movement to the producing wells, as well as the temperature level in it should provide the maximum possible volume of oil-containing non-draining matrix to a temperature of at least 250-350 ° C, at which at least 40-50% is extracted according to generalized experimental data contained in the light oil matrix.

In this regard, it should be emphasized that with the increase in the size of the thermal rim, the size of the heating zone of the non-drained zone also increases. Simultaneously with an increase in the speed of movement of the thermal rim in the drained zone, the heating depth of the adjacent non-drained zone decreases.

In turn, the size of the heat-generating rim in the drained zone and its speed of movement are largely determined by the rate of injection of the oxygen-containing mixture, in particular air and water, and the air-water ratio. Moreover, if the rate of injection of working agents leads to an increase in the size of the heat generation zone, then the water-air ratio can lead to both its increase and its reduction.

A known method and device for the development of viscous oil according to the patent of the Russian Federation for the invention No. 2418944, IPC E21B 43/04, publ. 05/20/2011, (prototype of the method and device).

The essence of the method lies in the fact that zones of in-situ oxidative and thermodynamic processes are created in the formation by introducing a bottomhole gas generator into the horizontal part of the casing string and igniting the fuel in it and mixing water into the combustion products.

The device comprises a water heater, fuel tanks and an oxidizing agent on the surface, a gas generator installed in the horizontal part of the casing of the heating well, connected by pipelines to the oxidizing tanks, fuel tanks and a water heater.

The principal feature of the proposed development method is that the air-water ratio of the water and air injected into the drained lithotypes of the rocks of the Bazhenov formation, the rate and pressure of their injection are determined from the condition that it is necessary to heat to the temperature not lower than 250 ° C the maximum possible volume of the oil-containing impenetrable matrix surrounding drainage heat-generating zones of the reservoir. The implementation of such regulation makes it possible to ensure not only effective miscible displacement of light oil from drained zones, but also the introduction into active development of oil-containing micropermeable zones.

In this regard, it should be emphasized that the injection of a water-air mixture allows us to realize not only in-situ oxidation processes, as provided for in a known manner, but also provide on this basis a miscible displacement of light oil and thermal effects, but also hydraulic action. As noted above, this effect allows to increase the drainage zone due to the creation of additional new cracks and partial opening of existing microcracks. It is obvious that the simultaneous thermal and hydraulic effects should lead to a synergistic result in the expansion of the drainage zone and a significant increase in its filtration characteristics.

The well-known gas generator according to the patent of the Russian Federation for utility model 136083, IPC No. E21B 43/24, publ. December 27, 2013 (a prototype of a downhole gas generator).

This downhole gas generator comprises a housing, to the upper end of which are connected pipelines of fuel, oxidizer and water, a combustion chamber, an outlet nozzle and a water mixer with combustion products.

The disadvantages of this downhole gas generator are its low efficiency and the possibility of burning the walls of the combustion chamber.

The task of creating a group of inventions is to bring the maximum possible amount of energy into a heating well while reducing energy costs in oil production.

Injection into the reservoir from the surface of the earth or from an offshore platform of superheated water with a subcritical temperature (below 374 ° C) or with a temperature higher than critical (above 374 ° C) and high overpressure, which allows reaching the indicated water temperatures without boiling and without steam formation directly on surface, but with the formation of a large amount of steam in the bottomhole or bottomhole zone of the well during the delivery of superheated water from the above-ground boiler plant.

It is known that at high overpressure of 218.5 atmospheres, water can be heated to a critical point corresponding to a temperature of 374 ° C. At the same time, the density of water during its heating to a critical point will remain almost unchanged from the original, which allows you to deliver it to the place of use - bottom-hole or bottom-hole zone of the well, in a compact form with small heat losses due to high speed due to pressure difference - more high on the surface of the earth and lower in the well. At the same time, due to lower pressure in the well, water will boil and a large amount of steam will be released into the well. Water with a subcritical point of 374 ° C can be obtained using a special ground-based boiler plant.

In the case of the presence of high pressure in the well, above 218.5 atmospheres, for the formation of steam in the above-ground boiler plant, it is necessary to raise the water temperature above the critical 374 ° C, for this to create a pressure above 218.5 atmospheres.

Due to the pressure of the water column in the supply pipe, the height of which can be several kilometers, additional pressure of the coolant - water will be formed.

The solution of these problems was achieved in a method for developing viscous oil fields, including the creation of a zone of in-situ oxidative and thermodynamic processes in the reservoir, by introducing a downhole gas generator into the horizontal part of the casing of the casing string and igniting fuel components in it: fuel with an oxidizing agent and mixing the preheated combustion products water, so that the fuel, the oxidizing agent and the heated water are pumped through several coiled tubing into the bottomhole gas generator, at Using water pump, water is pumped into the water heater installed before coiled tubing, the fuel components in the bottomhole gas generator are ignited using the spark plug, and the bottomhole gas generator is slowly moved through the synchronous operation of the coiled tubing along the entire horizontal section of the casing to the mouth, then removed from the heating well downhole gas generator, lower the tubing string with well filters in the horizontal part of the casing into it and carry out production from the well of the liquid phase, gaseous fractions and light evaporated oil products, separate and clean them, then all these operations are repeated repeatedly. The ratio of the combustion of the oxidizer and fuel components in the downhole gas generator can be carried out with an excess coefficient of the oxidizer in the range α = 0.9 ... 1.0. Water can be heated to below critical temperature. Water can be heated to supercritical temperature. The water pressure at the outlet of the water pump can be set such that, taking into account the hydrostatic pressure of the water in the borehole, its pressure exceeds the critical pressure of the water. A powder catalyst may be mixed with water. Gaseous fractions can be liquefied to heat water in a water heater.

The solution of these problems was achieved in a device for the development of a viscous oil field, containing a water heater, fuel tanks and an oxidizer on the surface, a gas generator installed in the horizontal part of the casing of the injection well, connected by pipelines to the oxidizer tanks, fuel and a water heater, so that as means for connecting the downhole gas generator with the oxidizer tanks, fuel and water heater selected pipe coiled tubing, and the downhole gas generator contains installed on e the upper end of the spark plug connected to an electronic unit, such as a timer. Oxidizer, fuel and water pumps may contain a common shaft connected to the drive. A water pump can be installed between the oxidizer and fuel pumps. The drive can be made in the form of an electric motor. The drive can be made in the form of a diesel engine. The drive can be made in the form of a gas turbine connected to a gas generator operating on the gas fraction extracted from the well.

The drive can be made in the form of a steam turbine connected by a steam line to a water heater operating on the gas fraction extracted from the well.

The solution of these problems was achieved in the downhole gas generator, comprising a housing, to the upper end of which are connected pipelines of fuel, oxidizer and water, a combustion chamber, an outlet nozzle and a water mixer with combustion products, characterized in that an ignition device having an spark plug is installed in its upper end , a timer and a source of electricity, the combustion chamber is made in the form of a cylinder installed with a gap in the coaxial body for water passage, the nozzle is made narrowing-expanding with critical tapered section between them, and the expanding parts and the mixer is combined with the combustion chamber and is in the form of holes at the junction of the cylindrical portion with the tapered portion of the nozzle and at the nozzle exit. Between the tapering-expanding nozzle and the housing, two inserts having fins on the inner surface can be installed. The height of the ribs can be made decreasing towards the critical section. Inserts can be made of copper.

The invention is illustrated in the drawings of FIG. 1 ... 19, where:

- in FIG. 1 shows a diagram of a device

- in FIG. 2 shows the design of the downhole gas generator,

- in FIG. 3 shows the design of the electronic unit and its connection with the downhole gas generator,

- in FIG. 4 shows a view of A,

- in FIG. 5 shows view B,

- in FIG. 6 shows the design of a tapering-expanding nozzle,

- in FIG. 7 shows a section C-C,

- in FIG. 8 shows the pump drive in the form of an electric motor,

- in FIG. 9 shows a pump drive in the form of a diesel engine,

- in FIG. 10 shows a pump drive in the form of a gas turbine,

FIG. 11 shows a pump drive in the form of a steam turbine,

- in FIG. 12 shows a control and management diagram,

- in FIG. 13 shows a scheme for pumping oil from a reservoir,

- in FIG. 14 are graphs of changes in specific heat flux, cooling water velocity and wall temperature of the combustion chamber and nozzle,

- in FIG. 15 is a water state diagram

- in FIG. 16 shows a diagram of oil and gas production using several wells,

- in FIG. 17 shows the design of coaxial flexible pipelines,

- in FIG. 18 shows a section C-C,

- in FIG. 19 is a diagram of oil production from an injection well.

A device for the development of viscous oil (Fig. 1 ... 19) 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. Downhole gas generator 6 was installed in the horizontal section 4 of the casing 2. In the upper part of the casing 2 at the mouth, i.e. a collector 9 is made above the surface 7 of rock 8. The horizontal section 5 is made within the oil reservoir 10.

The device has the following equipment installed on the surface 7 (Fig. 1):

the water tank 11 and the water heater 12, the oxidizer tank 13 and the oxidizer pump 14, the fuel tank 15 and the fuel pump 16. In addition, the device contains three coiled tubing: oxidizer coiled tubing 17, fuel coiled tubing 18 and water coiled tubing 19, respectively, with flexible pipes 20, 21 and 22.

Flexible pipelines of the oxidizing agent 20, fuel 21 and water 22 are connected to the downhole gas generator 6 and placed in the cavity 23 of the casing string 2.

Downhole gas generator 6 is designed to burn fuel in the oxidizer. In order to completely burn the fuel and there is no oxidizer left, it is necessary to ensure their stoichiometric ratio.

The stoichiometric ratio between the components of the fuel (oxidizing agent and fuel) is only a theoretical measure in assessing the actual composition of the fuel. The actual ratio between the components of the fuel is estimated through the coefficient of excess oxidizer α.

For α> 1.0, the fuel contains an excess of oxidizing agent, and for α << 1.0 - an excess of combustible elements.

From the point of view of thermodynamics, it is preferable to burn fuel at α = 1.

However, due to inaccuracy in the regulation of the consumption of fuel components and incomplete combustion, it is advisable to allow a small excess of fuel α = 0.9.

In the upper part, the casing 2 is closed by a sealed cover 24, in the openings of which flexible pipes 20 ... 22 pass. Flexible pipelines 20 ... 22 are sealed in the cover 24. The water supply system contains a water tank 11, a water supply pipe 25, a water pump 12, a flow regulator 26, a water heater 13 and coiled tubing 19. The water supply pipe 25 is connected to the inlet to the water heater 13 The outlet of the water heater 13 is connected to a flexible conduit 22, which is further connected to the bottomhole gas generator 6. A powder catalyst, for example, a powder of a noble metal: gold or platinum, can be mixed into the water. The mixing of the catalyst can be performed either in the water tank 11 or in the water supply pipe 25 (this option is not shown in Fig. 1 ... 16).

The oxidizer supply system comprises an oxidizer tank 13, an oxidizer pump 14, a flow regulator 27, and an oxidizer pipe 28, which connects the oxidizer tank 13 to the coiled tubing 17.

The fuel supply system comprises a fuel tank 15, a fuel pump 16, a flow regulator 29, and a fuel pipe 30 that connects the fuel tank 15 to the coiled tubing 19.

A gas sampling pipe 31 is connected to the manifold 9, which is connected to the inlet of the gas liquefaction installation 32, to the outlet of which a distribution pipe 33 is connected. Before the gas liquefaction installation 32, a gas sampling pipe 34 is connected containing a regulator 35 and a valve 36. The other end of this the pipeline is connected to a water heater 13.

In more detail, the design of the downhole gas generator 6 is shown in FIG. 2 and 3. The bottom-hole gas generator 6 comprises a body 37 in the form of a steel pipe and a sleeve 38 at the upper end screwed by a tapered thread 39. The upper end of the sleeve 38 along the tapered thread 40 is closed by a plug 41, through which flexible pipelines 20 ... 22 pass. The housing 37 is closed from above by a plug 42. Between the plugs 41 and 42, a partition 43 is made with the formation of cavities 44 and 45 between them. A flexible conduit 22 for supplying water enters the cavity 44 and a flexible conduit 21 supplying fuel enters the cavity 45. An oxidizer nozzle 46 and a fuel nozzle 47 are installed on the plug 42. An spark plug 48 is installed on the plug 41.

The plug 42 acts as the fire bottom of the combustion chamber 49. The combustion chamber 49 is made in the form of a cylindrical metal casing mounted coaxially to the housing 37 with a gap 50. A tapering-expanding nozzle 51 (a Laval nozzle) is attached to the combustion chamber 49, which contains a tapering part 52 and an expanding part 53 with a critical cross section 54 between them. The tapering-expanding nozzle 51 can accelerate combustion products to supersonic speeds. The flexible pipe 20 is connected to the nozzle of the oxidizer 47. The spark plug 48 is connected by a steel pipe 55 to the cavity 56 of the combustion chamber 49. (Fig. 3). An annular cavity 57 is made in the coupling 48, which connects the cavity 44 with openings 58 and 59 with a clearance 50 for pumping water to cool the combustion chamber 49 and nozzle 51.

A flow having supersonic speed creates sound and ultrasonic waves of tremendous power 140 ... 160 dB in a wide frequency range. Sound and ultrasonic vibrations of a wide range of frequencies penetrate the oil-containing rock and contribute to its separation from the rock, cracking the rock, which increases the oil flow rate in the well.

For mixing water with the combustion products, two rows of holes 60 and 61 are made respectively at the junction of the combustion chamber 49 and the nozzle 51 and at the outlet of the nozzle 51. Such a hole design improves cooling of the nozzle 51 (curtain cooling).

To improve cooling between the tapering and expanding parts, two inserts 62 having fins 63 on the inside can be installed with a gap. The fins 63 can be made of variable height with a decrease in the direction of the critical section, where the heat fluxes are maximum (Fig. 14). It is known that in the critical section of the nozzle the specific heat fluxes have maximum values and exceed the specific heat fluxes along the combustion chamber by 2 ... 3 times. Without cooling, the nozzle in the critical section burns out almost instantly with a ratio of fuel components close to stoichiometric. And even inefficient cooling (only one measure) will not save the situation. One of the important ways to increase the heat transfer coefficient from the wall to the cooling water is to increase its speed in the gap. Reducing the height of the fins can increase the heat transfer coefficient. In addition, the presence of fins helps to intensify the heat transfer process, and curtain cooling with water vapor reduces the temperature of the combustion products in the boundary layer.

To control the moment of ignition of the fuel, an electronic unit 64 can be used installed in the injection well 1 and mounted on the downhole gas generator 6 using the articulated rod 65. The electronic unit 64 is connected by an electric wire 66 to the spark plug 48.

A possible design of the electronic unit 64 is shown in FIG. 3. It contains a metal casing 67 with thermal insulation 68, inside of which there is an electric power source 69 (rechargeable battery) and an electronic key 70, for example a timer, connected by an electric connection 71 to transmit a signal at the moment of ignition.

The water pumps 12, the oxidizing agent 14 and the fuel 16 can have a common shaft 72 for matching the costs of the oxidizing agent, fuel and water (Fig. 8).

A water pump 12 is located between the oxidizer pumps 14 and the fuel 16. This will significantly increase the reliability of the pumps, as it eliminates the contact of the oxidizer and fuel, which can lead to an explosion.

The oxidizer pump 14 comprises an inlet housing 73, a screw 74, a centrifugal impeller 75, an outlet housing 76, a support 77 and a seal 78.

The water pump 12 includes an inlet housing 79, a screw 80, a centrifugal impeller 81, an outlet housing 82, a support 83 and a seal 84.

The oxidizer pump 16 comprises an inlet housing 85, a screw 86, a centrifugal impeller 87, an outlet housing 88, a support 89 and a seal 90.

Centrifugal impellers 75, 81 and 87 of all pumps are mounted on a common shaft 28, to which drive 91 is connected. As drive 91, an electric motor 92 can be used (Fig. 8), connected by electric wires 93 through a switch 94 to an electric power source 95.

It is possible to use a diesel engine 96 (Fig. 9) or a gas turbine 97 (Fig. 10) as a drive. The gas turbine 97 comprises an inlet casing 98, a nozzle apparatus 99 and an impeller 100. A gas generator 102 is connected to the inlet casing 98 by means of a gas duct 101.

Perhaps the use of a steam turbine 103 (Fig. 11). The steam turbine 103 has a structure similar to a gas turbine and is connected by a steam line 104 to a water heater 13, which is preferably made with two independent sections. In this case, the water heater 13 has a housing 105 in which a high-temperature heating section 106 and a low-temperature heating section 107 are installed. Nozzles 108 are made inside the housing 105, an exhaust pipe 109 is connected to the housing 105. A water pipe 110 is connected to the entrance to the low-temperature section 103, and to its exit is a steam line 104, the other end of which is connected to the input case 98 of the steam turbine 103.

In the process of oil and gas production (Fig. 12), the injection well 1 includes a tubing string 111 (tubing) with downhole filters 112, a suction pump 113, a separator 114, a filter 115, a pipe 116. The suction pump 113 has a drive 117 .

CONTROL AND MANAGEMENT SYSTEM

The monitoring and control system is shown in FIG. 13 and includes an oxidizer flow sensor 118, a fuel flow sensor 119, a water flow sensor 120, an oxidizer pressure sensor 121, a fuel pressure sensor 122, a water pressure sensor 123, a water temperature sensor at the outlet of the high temperature section 124, and a water temperature sensor at the outlet of the low temperature section 125. The oxidizer and fuel flow sensors 118 and 119 allow you to determine the ratio of the components of the fuel entering the downhole gas generator 6.

The device comprises a control unit 126, which is electrically connected 127 to sensors 118 ... 125 and to flow controllers 24, 27 and 29.

In FIG. 14 are given:

- a graph of the specific heat flux along the length of the combustion chamber and nozzle pos. 128,

- a graph of the change in the speed of movement of cooling water in the gap - pos. 129,

- a graph of the temperature of the wall of the combustion chamber and nozzle - pos. 130.

In FIG. 16 shows a diagram of oil and gas production using several wells.

In addition to the injection well 1, one or more production wells 131 were drilled with a collector 132 at the wellhead, to which a separator 133 is connected, which separates the produced product into oil, gas and water. The separator 133 is connected by a first outlet to an oil pipeline 134, and a second outlet to a gas desiccant 135, to the outlet of which a gas liquefaction unit 136 is connected. A first exit 137 of this installation is connected to an oil pipeline 134. A second outlet 138 is connected via a valve 139 to a fuel line 34 for supply nozzles 108 of heater 13 with liquefied gas.

To supply the water heater 13 with non-liquefied gas, the outlet from the gas dryer 135 through the valve 141 is also connected to the fuel line 34. This will reduce the cost of heating the water, since the imported fuel will in any case be more expensive.

To start the operation of the water heater 13 at the initial stage, it is advisable to use imported fuel.

In FIG. 17 and 18, the coaxially arranged flexible pipes 17 and 18 are shown. The oxidizing agent enters the bottomhole gas generator 6 through the cavity 142 of the flexible pipe 17, and fuel through the gap 143 between the flexible pipes 17 and 18. In this case, two will be used instead of three coiled tubings.

In FIG. 19 is a diagram of oil and gas production from an injection well using packers 144 between the casing string 2 and the tubing string 111 and the packer 145 located outside the casing 2 in the casing gap 146.

DEVICE OPERATION

Before the work is completed, an injection well 1 (horizontal) is drilled and a casing 2 is installed in it. In this case, the horizontal part 4 of the casing 2 is completely perforated with holes 5 (Fig. 1).

Using coiled tubing 17, 18 and 19 on flexible pipelines 20 ... 22, the bottomhole gas generator 6 is lowered into the casing 2 to the maximum depth into the bottomhole 1, drive 91 is launched (Fig. 8), which drives the centrifugal impellers 75.81 and 87 pumps 12, 14 and 16. The oxidizing agent, fuel and water enter the downhole gas generator 6 through coiled tubing 17 ... 19 through flexible pipes 20 ... 22.

Using the electronic key 70 in the electronic unit 64 (Fig. 3), voltage is supplied to the spark plug 48, as a result of which the fuel components of the oxidizer and fuel in the combustion chamber 49 are ignited. Supersonic combustion products flow from the tapering-expanding nozzle 51 into the injection well 1. Water cools the walls of the nozzle 51 and flows into it through two rows of holes 60 and 61, while the temperature of the combustion products decreases to prevent burnout of the casing 2. The combustion products warm the oil formation 10. Downhole gas generator 6 is slowly moved along the horizontal section 4 of the casing 2 to the side of the mouth. Moving can be discrete.

At the same time, gaseous products containing natural gas, light oil fractions and combustion products are taken from the collector 9 through a pipe 31. After filtration, gaseous hydrocarbons are liquefied in a liquefaction unit 32 and supplied to a consumer via a pipe 33.

The movement of the downhole gas generator can be discrete and lasts quite a long time to warm the surrounding space to a distance of at least 50 m. Then, the downhole gas generator 6 is raised to the surface and removed.

After that, the tubing string 111 with downhole filters 112 is lowered into the well 1 (Fig. 12). A pump 118 is turned on and a mixture of oil, gas and water is pumped out of the well 1, which is filtered in the filter 114, which is installed on the wellhead 1 and is divided into fractions in the separator 115. Through the pipe 116, the refined oil goes to the consumer, for example, to the oil pipeline. Liquefied fractions obtained as a result of oil production along with it can also be supplied to the pipeline.

Process control is carried out (Fig. 13) automatically or manually. To do this, use the readings of flow meters 118 ... 120 and sensors 121 ... 125. According to the readings of the oxidizer 118 and fuel 119, the optimum ratio of fuel components α = 0.9 ... 1.0 is maintained.

In FIG. 13 shows graphs of changes in the specific heat flux 128, the speed of cooling water 129 and the temperature of the wall 130 along the combustion chamber and the nozzle of the downhole gas generator. The use of a variable height of the ribs, decreasing to the critical confluence, prevented burnouts in this section and made the temperature of the nozzle walls almost constant along its length.

It is possible to supply gas to the heater from a neighboring well (Fig. 16).

In FIG. 17 and 18 show a possible variant of the liquid pipelines of the oxidizer 17 and fuel 18 with their coaxial arrangement.

The ratio of water consumption to fuel components (total fuel and oxidizer consumption) depends on the energy of the fuel components and the water temperature and can be performed in the range

Gvod ./ (Go + Gg) = 1,0 ... 5,0

The higher the water temperature, the more it will be required due to the fact that its specific heat of evaporation decreases with increasing temperature (table 1.)

The comparison results of the proposed method for the production of viscous oil with the prototype are given in table. 2

The heating time for a given volume decreased by 28 times.

Injection into the reservoir from the surface of the earth or from an offshore platform of superheated water with a subcritical temperature (below 374 ° C) or with a temperature higher than critical (above 374 ° C) and high overpressure, which allows reaching the indicated water temperatures without boiling and without steam formation directly on surface, but with the formation of a large amount of steam in the bottomhole or bottomhole zone of the well during the delivery of superheated water from a ground-based boiler plant.

At a high overpressure of 218.5 atmospheres, water can be heated to a critical point corresponding to a temperature of 374 ° C (Fig. 15). At the same time, the density of water during its heating to a critical point will remain virtually unchanged from the original, which allows you to deliver it to the place of use - bottom-hole or bottom-hole zone of the well in a compact form with low heat loss due to high speed due to pressure difference - higher on the surface of the earth and lower in the well. At the same time, due to lower pressure in the well, water will boil and a large amount of steam will be released into the well.

In the case of the presence of high pressure in the well, above 218.5 atmospheres, for the formation of steam in the heater (ground-based boiler plant), it is necessary to raise the water temperature above the critical 374 ° C, to create a pressure above 218.5 atmospheres.

Due to the pressure of the water column in the supply pipe, the height of which can be several kilometers, additional pressure of the heat carrier - water of the order of 100-300 atmospheres will be formed. This will reduce the load on the water pump and reduce the energy costs of its drive.

The use of a group of inventions allowed:

1. To increase the completeness of fuel combustion in the downhole gas generator to almost 100%, completely eliminating the ingress of oxidizing agent (oxygen) into the oil reservoir and to prevent explosions due to the accumulation of oxygen and its reaction with hydrocarbons. This is achieved by the ratio of the costs of the oxidizing agent and fuel α = 0.9 ... 1.0.

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

3. At the development site using the proposed method, oil recovery of 70% 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 with 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.

4. To reduce the warm-up time of the oil reservoir to 250 ° C from 14 months to 15 days compared with the prototype.

5. Use simultaneously with other methods of influencing the oil reservoir the acoustic impact, which will improve the permeability of the oil reservoir and lead to the formation of micro and macrocracks in it.

6. Use non-combustible fuel components for the downhole gas generator through the use of a spark plug.

7. Refuse the geophysical cable to control the ignition moment in the combustion chamber of the downhole gas generator.

8. At the same time as oil production, to produce and utilize gaseous hydrocarbons for own needs and for the consumer.

9. Improve the ecology of the production process by eliminating the emission or burning of gas in the atmosphere without the use of thermal energy.

Claims (18)

1. A method for developing viscous oil fields, including the creation of a zone of in-situ oxidative and thermodynamic processes in the reservoir by introducing a downhole gas generator into the horizontal part of the casing of the injection well and igniting fuel components in it: fuel with an oxidizing agent and admixing preheated water to the combustion products, characterized the fact that fuel, an oxidizing agent and heated water are pumped through several coiled tubing into a bottomhole gas generator, while water is pumped at the water pump’s power to the water heater installed before the coiled tubing ignites the fuel components in the bottomhole gas generator using the spark plug and slowly moves the bottomhole gas generator by synchronous operation of the coiled tubing along the entire horizontal section of the casing towards the mouth, then the bottomhole gas generator is removed from the heating well, lowered into it a tubing string with downhole filters in the horizontal part of the casing string and fluid is produced from the well phase, gaseous fractions and light evaporated oil products, separate and purify them, then all these operations are repeated repeatedly. 2. The method of developing a viscous oil field according to claim 1, characterized in that the ratio of the combustion of the oxidizer and fuel components in the bottomhole gas generator is carried out with an oxidizer excess coefficient in the range α = 0.9 ... 1.0. 3. A method for developing a viscous oil field according to claim 1 or 2, characterized in that the water is heated to a temperature below critical. 4. A method for developing a viscous oil field according to claim 1 or 2, characterized in that the water is heated to supercritical temperature. 5. A method for developing a viscous oil field according to claim 1 or 2, characterized in that the water pressure at the outlet of the water pump is set such that, taking into account the hydrostatic pressure of the water in the well in the bottom, its pressure exceeds the critical water pressure. 6. A method for developing a viscous oil field according to claim 1 or 2, characterized in that a powdery catalyst is mixed with water. 7. A method for developing a viscous oil field according to claim 1 or 2, characterized in that the gaseous fractions are liquefied to heat the water in the water heater. 8. A device for developing a viscous oil field containing a water heater, fuel tanks and an oxidizer on the surface, a gas generator installed in the horizontal part of the casing of the injection well, connected by pipelines to the oxidizer tanks, fuel and a water heater, characterized in that as a means of connection coiled tubing pipes are selected for the downhole gas generator with oxidizer tanks, fuel and water heater, and the downhole gas generator contains a candle mounted at its upper end for Egan, connected to an electronic unit, such as a timer. 9. A device for developing a viscous oil field according to claim 8, characterized in that the oxidizer, fuel and water pumps contain a common shaft connected to the drive. 10. A device for developing a viscous oil field according to claim 9, characterized in that the water pump is installed between the oxidizer and fuel pumps. 11. A device for developing a viscous oil field according to claim 10, characterized in that the drive is made in the form of an electric motor. 12. A device for developing a viscous oil field according to claim 10, characterized in that the drive is made in the form of a diesel engine. 13. A device for developing a viscous oil field according to claim 10, characterized in that the drive is made in the form of a gas turbine connected to a gas generator operating on the gas fraction extracted from the well. 14. A device for developing a viscous oil field according to claim 10, characterized in that the drive is made in the form of a steam turbine connected by a steam line to a water heater operating on the gas fraction extracted from the well. 15. A downhole gas generator comprising a housing, to the upper end of which fuel, oxidizer and water pipelines are connected, a combustion chamber, an outlet nozzle and a water mixer with combustion products, characterized in that an ignition device having an spark plug, a timer and an electric power source, the combustion chamber is made in the form of a cylinder mounted with a gap in the coaxial housing for water passage, the nozzle is made narrowing-expanding with a critical section between the narrowing and expanding parts of the range of this and the mixer is combined with the combustion chamber and is in the form of holes at the junction of the cylindrical portion with the tapered portion of the nozzle and at the nozzle exit. 16. The downhole gas generator according to claim 15, characterized in that between the tapering-expanding nozzle and the housing are two liners having fins on the inner surface. 17. The downhole gas generator according to claim 16, characterized in that the height of the ribs is made decreasing towards the critical section. 18. The downhole gas generator according to claim 16, characterized in that the liners are made of copper.

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