EA004696B1 - In-situ combustion for oil recovery - Google Patents

Abstract

1. A system for transmitting heat into a hydrocarbon containing formation surrounding a heat injection well, the system comprising: an oxidizing fluid source; an oxidant supply conduit disposed in the wellbore of the heat injection well, wherein the conduit is configured to provide an oxidizing fluid from the oxidizing fluid source to a reaction zone in the formation during use, and wherein the oxidizing fluid is selected to oxidize at least a portion of the hydrocarbons in the formation in the vicinity of the wellbore zone during use such that heat is generated at the reaction zone; and a combustion gases exhaust conduit disposed in the wellbore of the heat injection well for transmitting combustion gases through the wellbore of the heat injection well away from the reaction zone. 2. The system of claim 1, wherein the system is configured to allow heat to transfer substantially by conduction from the reaction zone to a selected section of the formation during use. 3. The system of claim1, wherein the oxidant supply and combustion gases exhaust conduits are equipped with pressure regulation devices which control the pressure in the reaction zone such that at least a substantial part of the combustion gases generated at the reaction zone are vented to the earth surface through the combustion gases exhaust conduit. 4. The system of claim 1, wherein the oxidant injection conduit and the combustion gases exhaust conduit extend co-axially to each other from a wellhead of the heater well into the hydrocarbon bearing formation, the oxidant injection conduit protrudes from the lower end of the oxidant injection conduit through at least a substantial part of the hydrocarbon bearing formation and the protruding lower part of the oxidant injection conduit is equipped with an array of oxidant injection ports via which in us oxidant is injected into an annular space between the oxidant injection conduit and the reaction zone. 5. The system of claim 1, wherein the oxidant injection conduit is an air injection conduit and is provided with an air injection pump and the air injection conduit and combustion gases exhaust conduits are each provided with a pressure control valve for controlling the pressure in the annular space between the perforated lower part of the oxidant injection conduit and the reaction zone such that said pressure is substantially equal to a pore pressure in at least part the surrounding hydrocarbon containing formation and transfer of combustion gases into the formation is inhibited. 6. The system of any one of claims 1-5, wherein the heat injection well further comprises an electric heater for transmitting heat into the reaction zone. 7. The system of any one of claims 1-5, wherein the heater well further comprises a fuel injection conduit for injecting fuel into the reaction zone. 8. A method for transmitting heat into a hydrocarbon containing formation surrounding a heat injection well, the method comprising: injecting an oxidant through an oxidant supply conduit disposed in the wellbore of the heat injection well to a reaction zone in the formation, inducing the oxidizing fluid to oxidize at least a portion of the hydrocarbons in the formation in the vicinity of the wellbore such that heat and combustion gases are generated in the reaction zone; and removing at least part of the combustion gases through an exhaust conduit disposed in the wellbore of the heat injection well away from the reaction zone. 9. The method of claim 8, wherein the heat generated in the reaction zone is transferred substantially by conduction from the reaction zone to a pyrolysis zone in the hydrocarbon containing formation where hydrocarbons are pyrolysed. 10. The method of claim 9, wherein one or more production wells traverse the hydrocarbon containing formation at selected distances from the heat injection well, and the fluid pressures in the heat injection well and each production well are controlled such that pyrolysed hydrocarbons products are induced to flow from pyrolysis zone through the formation into the production well or wells and that transfer of combustion gases from the reaction zone into any production well is inhibited. 11. The method of claim 8, 9 or 10, wherein the hydrocarbon containing formation is a coal layer. 12. The method of claim 8, 9 or 10, wherein the hydrocarbon containing formation is an oil shale deposit or a tar sand. 13. The method of any one of claims 8-12, wherein the heat injection well is pre-heated by an electric heater before oxidant is injected into the heat injection well.

Description

The present invention relates to a method and apparatus for heating a formation containing hydrocarbons, such as a coal seam or a deposit of bituminous shale, surrounding a well to supply heat.

The level of technology

The introduction of heat in the formation of bituminous shale is disclosed in US Patent Nos. 2,923,535 (Lungstrom) and 4,886,118 (Van Meurs et al.). In these prior art publications, it is described that electric heaters transfer heat to the formation of bituminous shale, for the purpose of pyrolysis of kerogen within the formation of bituminous shale. In addition, this heat can cause faults in the subterranean formation, which increases its permeability. This increased permeability can provide fluid transport to the production well, where fluid is removed from the formation of bituminous shale. In some of the methods described by Lungstrom, a gaseous medium containing oxygen is preferably introduced into the permeable formation, still hot from the preheating stage, in order to initiate combustion.

In US patent No. 2548360 described electrical heating element, which is located inside the viscous oil in the wellbore. The heating element heats and dilutes the oil, allowing the pumping of oil from the well. US Pat. No. 4,716,960 describes electrically heated oil well pipes by passing a low voltage current through a pipe in order to prevent the formation of a solid substance. In US Patent No. 5,065,818 to van Egmont, an electrical heating element is described that is cemented in a wellbore, without a housing surrounding the heating element.

In US patent No. 6023554 described electrical heating element, which is located inside the housing. The heating element emits thermal energy that heats the case. A granular solid filler material can be placed between the body and the formation. The body can heat the solid filler material due to thermal conductivity, which, in turn, transfers heat to the formation.

In US patent No. 4570715 Van Meurs et al. Describes an electrical heating element. This heating element has an electrically conductive core surrounding the layer of insulating material and the surrounding metal sheath. The conductive core has a relatively low resistance at high temperatures. Insulating material has electrical resistance properties, compressive strength and thermal conductivity, which are relatively high at high temperatures. An insulating layer prevents electrical discharge between the core and the metal sheath. This metal sheath has tensile properties and flow resistance properties that have relatively large values at high temperatures.

In US Patent No. 5,060,287 to van Egmont, which is incorporated by reference as if fully set forth in this invention, an electrical heating element is described which has a core of a nickel-copper alloy.

Combustion can be used to heat the formation. Burning fuel to heat a formation may be more economical than using electricity to heat a formation. Several different types of heaters can be used to burn fuel as a heat source to heat the formation. This combustion may occur in the formation, in the well and / or near the surface.

U.S. Patent Nos. 4,662,443, 4,662,439 and 4,648,450 describe methods of in-situ combustion, i.e., burning hydrocarbons inside a subterranean formation in which an oxidizer, such as air, is pumped into the formation. The oxidizer can ignite so that the flame front moves towards the production well. The oxidizer injected into the formation may pass through the formation along fracture lines in the formation. The ignition of the oxidant may not lead to a burning front that is uniformly progressed through the formation.

In addition, it is known to use a flameless burner for burning fuel, which is introduced into a heated well. U.S. Patent Nos. 5,255,742 (Mikus), 5,404,952 (Weingar et al.), 5,862,858 (Wellington et al.) And 5,899,269 (Wellington et al.), Which are incorporated by reference as if fully described in this invention, are described as flameless. burner. Flameless combustion can be accomplished by heating the fuel and combustion air to a temperature above the auto-ignition temperature of the mixture. To carry out the combustion of fuel and air can be mixed in the heating zone. A catalytic surface may be provided in the heating zone of the flameless burner in order to lower the auto-ignition temperature of the fuel / air mixture. In these known flameless burners, fuel and oxidant are introduced into a heated well through separate supply lines, or as a mixture, through a single supply line, while flue gases are brought to the surface through an exhaust line, which can be located coaxially, around fuel supply lines and / or oxidizing agent.

In addition, it is known that heat can be brought to the formation from a surface heater. This surface heater produces flue gases that circulate through the wellbore to heat the formation. Alternatively, surface burners can be used to heat the fluid (fluid) that transports the heat that passes through the wellbore to heat the formation. Examples of flame heaters or surface burners that can be used to heat a subterranean formation are illustrated in U.S. Patents 6,056,057 (Weingar et al.) And 6,079,499 (Mikus et al.), Both of which are fully incorporated into the description by reference.

According to the restrictive part of paragraphs. 1 and 8, a device and method are known from U.S. Pat. No. 3,010513. In a known device, the formation around the heating well cracks and the fractures are filled with combustible solid and proppant. In a known device, irregular heating structures are created in the surrounding formation, since faults have an irregular length and shape.

A disadvantage of known surface and well-placed heaters in which fuel, oxidizer and / or flue gases circulate through a heating well, is that the casing and other pipelines in the heating well must be made of heat-resistant steel, and in particular the casing is exposed to large compression forces resulting from thermal expansion of the surrounding formation. Therefore, the casing in the heating well must be made of an expensive grade of stainless steel with heat resistance and corrosion resistance. In addition, for supplying fuel or for supplying electricity, if an electric heater is mounted, usually complex infrastructure is required, which is therefore costly.

A disadvantage of the known in-situ combustion methods is that in a formation containing hydrocarbons, cracks of irregular structure are created, and that only part of hydrocarbons located near the cracks are oxidized, so that only cracks are heated in an irregular and uncontrolled manner.

The aim of the present invention is to eliminate the disadvantages of the known methods of in-situ combustion, combustion of injected fuel and electrical heating, in order to provide an inexpensive method of in-situ heating and a device that transmits a controlled amount of heat evenly throughout the formation.

Summary of Invention

In accordance with the present invention, a device that transfers heat to a formation surrounding a well for supplying heat and containing hydrocarbons includes an oxidizing fluid source;

an oxidizer supply pipe located in the wellbore for supplying heat, the pipeline having a configuration that supplies the oxidizing fluid from the source of oxidizing fluid to the reaction zone during the operation of the formation, and the oxidizing fluid is chosen so that it oxidizes at least , a portion of the hydrocarbons in the formation, near the wellbore zone during operation, so that heat is generated in the reaction zone;

and a flue gas conduit located in the wellbore for supplying heat for passing the flue gases through the wellbore to supply heat, withdrawing from the reaction zone, the oxidizer supplying conduit having a configuration that provides an oxidizing fluid through the reaction zone by diffusion in the gas phase and / or convection.

Preferably, the device has such a configuration that ensures the transfer of heat from the reaction zone to selected sections of the formation during operation mainly due to thermal conductivity.

In addition, it is preferable that the pipelines for supplying the oxidant and for flue gases are equipped with pressure control devices that control the pressure in the reaction zone so that a significant part of the flue gases formed in the reaction zone is brought to the ground surface through the flue pipe gases.

In some cases, a device for creating pressure may be used in order to ensure the removal of a portion of the flue gases to the surface of the earth, with the other part penetrating into the reaction zone. This can provide a higher pressure in the wellbore than in an area away from the wellbore. This pressure drop can lead to accelerated transport of the oxidizing fluid into the reaction zone and / or to an increase in its quantity, resulting in increased heat generation from the reaction zone.

It is advisable that the oxidizer supply pipeline and the flue gas extraction pipeline pass coaxially relative to each other from the heating well bore into a formation containing hydrocarbons; the oxidizer supply pipeline extends from the lower end of the oxidizer supply pipeline, at least through a significant part of the formation containing hydrocarbons, and the protruding lower part of the oxidizer supply pipeline is provided with a set of oxidizer input holes through which the oxidizer used is injected with a near-sound or supersonic speed in annular space between the oxidizer supply line and the reaction zone.

The oxidizer inlet line may be an air inlet pipe that is equipped with an air compressor, each air inlet pipe and an intake pipe for flue gases may be equipped with a valve that controls the pressure in the annular space between the perforated lower part of the oxidizer inlet pipe and the reaction zone so that the pressure is almost equal to the pressure in the well, at least in the part of the adjacent formation containing hydrocarbons, and slowed down the course of flue gases in this formation. However, in some cases it is possible to allow partial penetration of flue gases into the formation in order to accelerate the transition of the oxidizing fluid into the reaction zone and increase the heat generation in the formation.

To start or maintain the combustion process in the formation, the heating well may be equipped with an electric heater to transfer heat to the reaction zone or a pipeline to introduce fuel to supply additional quantity of fuel to the reaction zone.

Detailed Description of the Invention

The invention will be described in more detail using examples, with reference to the accompanying drawings, in which FIG. 1 shows an embodiment of the invention with a natural location of a heat source with a combustion chamber.

FIG. 2 shows part of the overlap of a formation with a heat source.

FIG. 3 and 4 - embodiments of the natural location of the heater with the combustion chamber; and in FIG. 5 and 6 are embodiments of a device for heating a formation.

According to the invention, a hydrocarbon containing formation is heated by oxidizing the hydrocarbons in place in the formation surrounding the well to supply heat; This device is also called a heating system with a natural combustion chamber (ΝΏΟ). Heat released can be transferred by convection to the part of the formation surrounding the heating well to heat it, while the transition of flue gases from the reaction zone to the formation is slowed down or partially slowed down.

A temperature sufficient to maintain oxidation may be, for example, at least about 200 or 250 ° C. However, a temperature sufficient to maintain oxidation will tend to change, for example, depending on the composition of the hydrocarbons in the formation containing the hydrocarbons. Water can be removed from the formation before the formation is heated. For example, it is possible to draw water from the formation with the help of wells diverting water. The heated part of the formation may be near or almost near the production in the formation containing hydrocarbons. Production in the formation can be a heating well formed in the formation. A heating well may be formed in accordance with any one of the embodiments described in the invention. The heated portion of a hydrocarbon containing formation may extend radially from an output width of approximately 0.5 to 1.2 m. However, this width may also be less than approximately 0.9 m. The width of the heated portion of the formation may vary. In some embodiments, this change will depend, for example, on the width that is needed to generate enough heat during carbon oxidation in order to maintain the oxidation process without providing heat from an additional heat source.

After a portion of the formation has been heated to a temperature sufficient to maintain oxidation, an oxidizing fluid may be fed into the production to oxidize at least a portion of the hydrocarbons in the reaction zone or in the heat source zone, inside the formation. The oxidation of hydrocarbons in the reaction zone will generate heat. In most embodiments, the heat released will be transferred from the reaction zone to the pyrolysis zone of the formation. In some embodiments, the heat released will be transmitted at an intensity of approximately between 650 and 1650 W per meter, as measured by the depth of the reaction zone. By oxidizing at least part of the hydrocarbons in the formation, the amount of energy supplied to the heater for initial heating can be reduced or the energy can be turned off. As a result, the cost of the energy supplied can be significantly reduced, and thus a significantly more efficient system for heating the formation is provided.

In one embodiment, the pipeline may be located in the excavation in order to ensure the supply of oxidizing fluid to the excavation. The pipeline may have openings for flow or other devices for controlling flow (for example, slots, venturi meters, valves, etc.) to ensure the flow of oxidizing fluid into the output. The term "holes" includes from

Ί Versions that have a wide variety of section shapes, including (but not limited to) round, oval, square, rectangular, triangular, slotted, or other regular or irregular shapes. Flow-through holes can be critical-section holes through which fluids flow at high speeds, such as supersonic, providing an almost constant flow of oxidizing fluid into the production, regardless of the pressure inside it.

In some embodiments, the number of flow holes that can be formed or connected to the pipeline may be limited by the diameter of the holes and the desired distance between the holes along the length of the pipeline. For example, when the diameter of the holes decreases, the number of holes may increase and vice versa. In addition, when the desired distance between the holes increases, the number of flow holes may decrease and vice versa. The diameter of the holes can be determined, for example, by the pressure in the pipeline and / or the desired flow rate through the holes. For example, for a flow rate of approximately 1.7 normal cubic meters per minute (cubic meters / min) at an absolute pressure of approximately 7 bar, the diameter of the holes may be about 1.3 mm and the distance between the holes is approximately 2 m.

For holes with a smaller diameter, there will be a tendency to block more easily than for holes with a larger diameter, for example, due to the presence of contaminants in the fluid at the inlet or sedimentation of solids inside or near the holes. In some embodiments, the number and diameter of the holes can be adjusted so that a more uniform or almost uniform temperature profile of heating can be obtained throughout the depth of the formation, within the development. For example, the depth of the heated formation, which presumably has an approximately uniform temperature profile of heating, may be greater than approximately 300 m, or even greater than approximately 600 m. However, this depth may vary, for example, depending on the type of formation being heated and / or desired performance level.

In some embodiments, the flow-through openings may be arranged in a spiral manner around the pipeline inside the development. Flow-through openings can be placed in a spiral at a distance of approximately 0.3 to 3 m between the openings. In some embodiments, this distance may be about 1 to 2 meters, or, for example, about 1.5 meters.

The flow of oxidizing fluid into the formulation can be adjusted to control the rate of oxidation in the reaction zone. In addition, the oxidizing fluid may cool the pipeline so that it is slightly heated during oxidation.

FIG. 1 illustrates an embodiment of the invention with a natural arrangement of a combustion chamber having a configuration for heating a formation containing hydrocarbons. Pipeline 512 may be placed in development 514 in formation 516. Pipeline 512 may have an internal pipe 513. An oxidizing fluid source 508 may supply the oxidizing fluid 517 to an internal pipe 513. Critical flow holes 515 may be along the length of the internal pipe 513. These critical flow orifices may be spirally (or in any other way) along the length of the inner pipe 513 in design 514. For example, critical flow orifices 515 may be spirally at a distance of about 1 to 2.5 m between adjacent orifices. In addition, critical flow ports 515 may be configured as described below. Inner tube 513 at the bottom can be sealed. Oxidizing fluid 517 may be fed to development 514 through critical flow ports 515 of the inner pipe 513.

Critical flow ports 515 may be configured such that an oxidizing fluid flow 517 is supplied through each critical port orifice at the same rate. In addition, critical flow holes 515 can provide an almost uniform flow of oxidizing fluid 517 along the length of pipeline 512. Such a flow can provide a nearly uniform heating of formation 516 along the length of pipeline 512.

Bulk material 542 may enclose conduit 512 in formation overlap 540. Bulk material 542 may substantially inhibit fluid flow from development 514 to surface 550. Bulk material 542 may include any material that may be configured to prevent fluids from flowing to surface 550, such as cement, sand, and / or gravel.

Typically, oxidation products 519 are included in line 512 from development 514. Oxidation products 519 may contain carbon dioxide, nitrogen oxides, sulfur oxides, carbon monoxide, and / or other products formed by the interaction of oxygen with hydrocarbons and / or carbon. Oxidation products 519 can be removed through conduit 512 to surface 550. Oxidation products 519 can flow along the surface of reaction zone 524 into development 514 to the nearest upper edge of development 514, where oxidation products 519 can exit through conduit 512. Oxidation products 519 can also be removed through one or more pipelines located in development 514 and / or in formation 516. For example, oxidation products 519 can be removed through a second pipeline located in development 514. Removal of products 519 is oxidized pipeline can virtually inhibit oxidation products 519 into the production well located in formation 516. Critical flow holes 515 can also have a configuration that practically inhibits the flow of oxidation products 519 into the internal pipe 513.

The flow rate 519 of oxidation products can be balanced with the flow rate of the oxidizing fluid 517, in order to maintain almost constant pressure inside the mine 514. With a heated section length of 100 m, the flow rate of the oxidizing fluid can be approximately 0.5 to 5 normal cubic meters / min, or from about 1.0 to 4.0 standards. cubic meters / min. The production pressure can be, for example, approximately 8 abs. bar. The oxidizing fluid may oxidize at least a portion of the hydrocarbons in the heated portion 518 of the hydrocarbon containing formation 516 in the reaction zone 524. The heated portion 518 of the formation may first be heated to a temperature sufficient to maintain oxidation with an electric heater, as shown in FIG. 5, or using any other suitable device or method described in this invention. In some embodiments, electrical heaters may be placed inside or connected to the outside of conduit 513.

In some embodiments, it is advantageous to regulate the pressure within production 514 in order to prevent the oxidation products and / or oxidizing fluid from escaping into the formation pyrolysis zone. To achieve this goal, in some cases, the pressure inside the mine 514 will be balanced by the pressure inside the formation. In other embodiments, a portion of the combustion products is allowed to enter the formation, in order to create a pressure difference that leads to an increase in the flow of oxidizing fluid in the direction of the reaction zone, and as a result, the heat release rate increases.

Although the heat of the oxidation process is transferred to the formation, the oxidation product stream 519 (and excess oxidizing fluid, such as air) through the formation and / or into the production well inside formation 516 can be significantly suppressed. Instead, oxidation products 519 (and excess oxidizing fluid) are removed (eg, via a conduit, such as conduit 512), as described in this invention. Thus, heat is transferred to the formation from the oxidation process, but the effect of the pyrolysis zone on oxidation products 519 and / or the oxidizing fluid can be practically suppressed and / or partially or completely prevented.

In some embodiments, a portion of the pyrolysis products near the reaction zone 524 may also be oxidized in the reaction zone 524 in addition to carbon. Oxidation of pyrolysis products in reaction zone 524 can provide additional heat to formation 516. When such oxidation of pyrolysis products occurs, it is desirable that oxidation products are removed from this oxidation process (for example, through a pipeline, such as pipeline 512) near the reaction zone, as described in this the invention, thereby preventing contamination of other pyrolysis products in the formation with oxidation products.

Pipeline 512 may be configured to remove oxidation products 519 from development 514 in formation 516. Oxidizing fluid 517 in the internal pipe 513, as such, may be heated by heat exchange oxidation products 519 in the overlap of section 540 in pipeline 512. Oxidation products 519 can be cooled by transferring heat to the oxidizing fluid 517. Thus, the oxidation of hydrocarbons within formation 516 can improve the thermal efficiency of the process.

Oxidizing fluid 517 may be transported through reaction zone 524 or a heat source zone due to diffusion in the gas phase and / or convection. Diffusion of oxidizing fluid 517 through reaction zone 524 may be more efficient at relatively high oxidation temperatures. Diffusion of oxidizing fluid 517 can prevent the development of local overheating and the formation of "hot spots" in the formation. Diffusion of the oxidizing fluid through formation 516 is typically a mass transfer process. In the absence of external influence, the rate of diffusion of oxidizing fluid 517 may depend on the diffusion coefficient of oxidizing fluid 517 through the formation 516. The diffusion coefficient can be determined by measurements or by calculation based on the kinetic theory of gases. In general, the oxidizing fluid 517 can be transported by random motion through formation 516 from a region of high concentration to a region of low concentration. The convection of the oxidizing fluid from the injection holes to the reaction zone will be determined by the pressure differential between the well and the reaction zone based on the laws of fluid flow through porous media.

Over time, when hydrocarbons are oxidized, the reaction zone may slowly expand in the radial direction to a larger diameter inside the mine. In many embodiments, an approximately constant width of the reaction zone may be maintained.

524. For example, reaction zone 524 may expand radially at a rate of less than about 0.91 m / year for a formation containing hydrocarbons. For example, for a carbon containing formation, the reaction zone 524 may expand radially at a rate of about 0.5 to 1 m / year. For a formation containing bituminous shale, the reaction zone 524 may expand radially at a speed of approximately 2 m in the first year, and at a slower rate in subsequent years due to an increase in the volume of the reaction zone 524 with a radial expansion of the reaction zone 524. This reduced speed may be from approximately 1 m / year to 1.5 m / year. Reaction zone 524 may expand at a reduced rate for formations with a higher hydrocarbon content (eg, coal) and at an increased rate for formations, with a higher content of inorganic materials (eg, bituminous shale), because there are more hydrocarbons in the bulk of formations with a higher hydrocarbon content. available for burning.

The flow rate of the oxidizing fluid 517 to the production 514 may increase when the diameter of the reaction zone 524 increases, in order to maintain an almost steady-state value of the oxidation rate per unit volume. Thus, an almost constant temperature can be maintained within reaction zone 524. The temperature inside the reaction zone 524 may be from about 650 to 900 ° C, or, for example, about 760 ° C.

The temperature inside the reaction zone 524 may vary, for example, depending on the desired heating rate of the selected section 526. The temperature inside the reaction zone 524 may increase or decrease due to an increase, or a corresponding decrease, in the flow rate of the oxidizing fluid 517 to the output 514. However, the temperature of the pipeline 512 , inner pipe 513 and / or metallic materials inside the mine 514 may not exceed the temperature at which metallic materials may begin to deform or undergo rapid corrosion .

Increasing the diameter of the reaction zone 524 can provide relatively quick heating of hydrocarbon containing formation 516. As the diameter of the reaction zone 524 increases, the amount of heat released per unit time in the reaction zone 524 may also increase. Increasing the amount of heat released per unit time in the reaction zone can in many cases provide an increased heating rate of the formation 516 for some time, even without increasing the temperature in the reaction zone or the temperature in the pipe 513. Thus, over time, an increased heating rate can be achieved without installing additional heat sources and without increasing t temperature In some embodiments, the heating rate can be increased, although a decrease in temperature is allowed (often lowering the temperature can prolong the service life of the equipment used).

When using carbon from the formation as a fuel, a naturally distributed combustion chamber can significantly reduce energy costs. Thus, an economical method of heating formations can be developed, the operation of which with other methods of heating would be economically inexpedient. In addition, a smaller number of heaters can be placed throughout the extended region of the formation 516. This can reduce equipment costs associated with heating the formation 516.

The heat released in the reaction zone 524 can be transferred due to the thermal conductivity of individual areas 526 of the formation 516. In addition, the heat released can be transferred to a lesser extent from the reaction zone to certain sections by convection. Separate areas 526, sometimes referred to as the “pyrolysis zone”, can be practically adjacent to the reaction zone 524. Since oxidation products (and excess oxidizing fluid, such as air) are usually removed from the reaction zone, the pyrolysis zone can receive heat from the reaction zone without affecting on it, oxidation products or oxidizing agents that are in the reaction zone. Oxidation products and / or oxidizing fluid can cause the formation of unwanted products if they are present in the pyrolysis zone. For example, in some embodiments, it is desirable to carry out pyrolysis in a reducing environment. Thus, it is usually useful to prevent the transfer of heat from the reaction zone to the pyrolysis zone while suppressing or preventing the penetration of oxidation products and / or oxidizing fluid into the pyrolysis zone.

The pyrolysis of hydrocarbons or other processes controlled by heat can take place in the selected heated area 526. The selected area 526 can be heated to a pyrolysis temperature between approximately 270 and 400 ° C. The temperature in the selected area 526 can be increased by heat transfer from the reaction zone 524. The rate of temperature increase can be selected, as indicated in any of the embodiments of this invention. The temperature in the formation 516, in the selected area 526 and / or in the reaction zone 524 can be adjusted so that the formation of nitrogen oxides can be practically prevented. Typically, nitrogen oxides are formed at a temperature of approximately above 1200 ° C.

The temperature inside the development 514 can be monitored using a thermocouple located in the design 514. The temperature inside the development 514 can be controlled in such a way as to maintain it within the selected interval. This selected interval may vary, for example, depending on the desired heating rate of formation 516. The temperature in the selected interval can be maintained by increasing or decreasing the flow rate of oxidizing fluid 517. For example, if the temperature inside the development 514 falls below the selected temperature range, you can increase the flow rate oxidizing fluid 517 in order to enhance combustion and thereby increase the temperature inside the development 514. Alternatively, the thermocouple may be located in pipeline 512 and / or boundary of the reaction zone 524 with appropriate temperature control.

In some embodiments, one or more naturally distributed combustion chambers may be located along a production well and / or horizontally. In this case, there is a tendency to reduce the pressure drop along the heated part of the well, thereby facilitating more uniform heating of the development and improving process control.

In some embodiments, the presence of air or molecular oxygen O ₂ in oxidation products 519 can be monitored. Alternatively, the amount of nitrogen, carbon monoxide, carbon dioxide, nitrogen oxides, sulfur oxides, etc. can be controlled in oxidation products 519. Control of the composition and / or amount of products 519 oxidation can be used to calculate the heat balance, process diagnostics, process control, etc.

FIG. 2 shows an embodiment of a part of the overlap with a naturally located combustion chamber, which is described in FIG. 1. The overlap housing 541 may be located in the overlap 540 of the formation 516. The overlap housing 541 may be substantially surrounded by materials (such as insulating material such as cement) that can practically prevent the overheating of the overlap 540. The overlap housing 541 may be made of a metal material such as carbon steel, without being limited to this material.

The floor frame may be located in the reinforcement material 544, in the ceiling 540. The reinforcement material 544 may be, for example, cement, sand, concrete, etc. Bulk material 542 may be located between overlap body 541 and development 514 in formation 516. Bulk material

542 can be any practically non-porous material (for example, cement, concrete, cement mortar, etc.). Bulk material 542 may prevent fluid flow beyond pipeline 512 and between development 514 and surface 550. Internal pipe 513 may provide fluid to development 514 in formation 516. Combustion products (or excess oxidizing fluid) from development 514 in formation 516 can be removed by pipeline 512. The diameter of the pipeline 512 can be determined by the number of combustion products formed by oxidation in a naturally located combustion chamber. For example, for larger amounts of combustion products formed in a naturally located combustion chamber, a larger diameter pipe will be required.

In an alternative embodiment, at least a portion of the formation may be heated to such a temperature at which at least a portion of the formation containing hydrocarbons can be turned into coke and / or coal. Coke and / or coal can form at temperatures above approximately 400 ° C and at a high heating rate (for example, approximately above 10 ° C per day). In the presence of an oxidizing fluid, coke or coal will be oxidized. The oxidation of coke or coal can generate heat, as described in any of the embodiments of this invention.

FIG. 3 shows an embodiment of a natural arrangement of a heater with a combustion chamber. Insulated conductor 562 may be connected to conduit 532 and located in development 514 in formation 516. Insulated conductor 562 may be located inside conduit 532 (thereby ensuring the ability to restore insulated conductor 562) or alternatively connected to the outer surface of conduit 532. Such an insulating material may include minerals, ceramics, etc. Pipeline 532 may have 515 critical flow openings located along the length of the pipe inside the 514 development. Holes 515 are critical stream may have the configuration described above. To generate radiation heat in the design 514, an electric current can be passed through the insulated conductor 562. The pipeline 532 may have a configuration that serves to return the current. Insulated conductor 562 may be configured to heat part of the formation 518 to a temperature that is sufficient to maintain the oxidation of hydrocarbons. The formation portion 518, reaction zone 524, and selected area 526 may have the characteristics described in this invention. Such temperatures may include the temperatures described in this invention.

The oxidizing fluid source 508 may supply the oxidizing fluid to conduit 532. The oxidizing fluid may enter development 514 through critical flow ports 515 in conduit 532. The oxidizing fluid may oxidize at least part of the hydrocarbon containing formation in the reaction zone 524. Reaction zone 524 may have characteristics that are indicated in this invention. The heat released in the reaction zone 524 may be transferred to a selected area 526, for example, by convection, radiation and / or heat conduction. The oxidation product can be removed through a separate pipeline, located in development 514, or through an opening 543 (not shown in FIG.) In the ceiling housing 451. A separate pipeline may be configured as described in this invention. Bulk material 542 and reinforcing material 544 may be configured as described in this invention.

FIG. 4 shows an embodiment of a naturally located combustion chamber with an added fuel line. The fuel pipe 536 may be located in development 514. In certain embodiments, it may be located in close proximity to the pipeline 533. Along the length of the fuel pipeline 536 there may be critical flow holes 535 inside the development 514. Critical flow holes 515 may exist along the pipeline 533 inside the design 514. The critical flow ports 515 may be configured as described in this invention. Critical flow openings 535 and critical flow openings 515 may be located respectively in fuel line 536 and pipe 533 so that the flow of fuel entering through fuel line 536 and oxidizing fluid entering through pipe 533 cannot significantly heat fuel line 536 and / or pipeline 533 in the combustion process. For example, the fuel and the oxidizing fluid can interact when the streams are in contact, and the heat of reaction is released. The heat of this reaction can heat the fuel pipe 536 and / or pipe 533 to a temperature that is sufficient to start the actual melting of the metallic materials of the fuel pipe 536 and / or pipe 533 if the reaction occurs near the fuel pipe 536 and / or pipe 533. Therefore, when designing the location critical flow holes 535 in fuel line 536 and critical flow holes 515 in pipe 533 should be placed in such a way that the flow of fuel and oxidizing fluid could not react to a large extent near the pipelines. For example, pipelines 536 and 533 may be mechanically connected, so that the holes are oriented in the opposite direction, and so that the holes face the formation 516.

When the fuel flow interacts with the oxidizing fluid, heat is generated. The fuel flow and oxidizing fluid may have the characteristics described below. The fuel stream can be, for example, natural gas, ethane, hydrogen, or synthetic gas that is produced in the in situ process in another part of the formation. The heat released can be spent so as to heat part of the formation 518 to a temperature that is sufficient to maintain the oxidation of hydrocarbons. When part of the formation 518 is heated to a temperature that is sufficient to maintain the oxidation of hydrocarbons, the flow of fuel fluid into the production can be reduced or turned off. Alternatively, you can continue to supply fuel during the formation heating process, and as a result, the heat accumulated in the carbon will be used to maintain the temperature in development 514 above the auto-ignition temperature of the fuel.

The oxidizing fluid may oxidize at least a portion of the hydrocarbons in the reaction zone 524. The heat released will be transferred to a selected area 526, for example, by convection, radiation and / or heat conduction. The oxidation product can be removed through a separate pipeline, located in development 514, or through an opening 543 (not shown in FIG.) In the ceiling housing 541. Bulk material 542 and reinforcing material 544 may be configured as described in this invention.

FIG. 5 illustrates an embodiment of a device configured to heat a formation containing hydrocarbons. Electric heater 510 may be located within development 514 in hydrocarbon containing formation 516.

Development 514 may be formed by overlapping 540 in formation 516. Development 514 may have a diameter of at least 5 cm. For example, development 514 may have a diameter of about 13 cm. Electric heater 510 may heat at least part 518 of the formation 516 containing hydrocarbons to a temperature that is sufficient to maintain oxidation (for example, 260 ° C). The formation portion 518 may be approximately 1 m wide. An oxidizing fluid (eg, liquid or gaseous) may be fed into the production through conduit 512 or any other suitable device for transporting fluid. Pipeline 512 may have critical flow ports 515 located along the length of the pipeline. Holes

515 critical flow can be configured as described in this invention.

For example, conduit 512 may be a tube or conduit having a configuration that provides an oxidizing fluid to develop 514 from an oxidizing fluid source 508. For example, conduit 512 may be a stainless steel tube. The oxidizing fluid may include air or any other oxygen-containing fluid (for example, hydrogen peroxide, nitrogen oxides, ozone). The mixture of oxidizing fluid may include, for example, a fluid containing 50% oxygen and 50% nitrogen. In some embodiments, the oxidizing fluid may also include compounds that release oxygen when heated, as described in this invention, such as hydrogen peroxide. The oxidizing fluid may oxidize at least a portion of the hydrocarbons in the formation.

In some embodiments, the heat exchanger located outside the formation may be configured to heat the oxidizing fluid. The heated oxidizing fluid may be fed into the development (directly or indirectly) from the heat exchanger. For example, a heated oxidizing fluid may be supplied from a heat exchanger to a development through a pipeline located in development and connected to a heat exchanger. In some embodiments, the conduit may be a stainless steel tube. The heated oxidizing fluid may be configured to provide heat, or at least may contribute to heat at least part of the formation to a temperature that is sufficient to maintain the oxidation of the hydrocarbons. After a part of the formation has been heated to this temperature, it is possible to weaken (or turn off) the heating of the oxidizing fluid in the heat exchanger.

FIG. 6 illustrates another embodiment of a device configured to heat a hydrocarbon containing formation. Heat exchanger 520 may be located outside development 514 in a hydrocarbon containing formation 516. Development 514 may be formed by overlapping 540 in formation 516. Heat exchanger 520 may deliver heat from another process to the surface, or it may include a heater (eg, electric or combustion heater). The oxidizing fluid source 508 may deliver the oxidizing fluid to the heat exchanger 520. The heat exchanger 520 may heat the oxidizing fluid (for example, above 200 ° C, or a temperature that is sufficient to maintain the oxidation of the hydrocarbons). The heated oxidizing fluid may be fed to development 514 via conduit 521. Pipeline

521 may have critical flow holes that are located along the length of the pipe. Critical flow ports 515 may be configured as described in this invention. The heated oxidizing fluid may heat, or at least contribute to, heat at least part of the formation 518 to a temperature that is sufficient to maintain the oxidation of the hydrocarbons. The oxidizing fluid may oxidize at least a portion of the hydrocarbons in the formation.

In another embodiment, the fuel fluid may be oxidized in a heater located outside the hydrocarbon containing formation. This fuel fluid may be oxidized by an oxidizing fluid in a heater. As an example, the heater may be an igniter heater. The fuel fluid can be any fluid that can interact with oxygen. An example of a fuel fluid may be methane, ethane, propane, or any other hydrocarbon, or hydrogen, or syngas. The oxidized fuel fluid can flow into the development from the heater through the pipeline and return to the surface via another pipeline in the floor. These pipelines can be connected inside the ceiling. In some embodiments, the conduits may be concentric. The oxidized fuel fluid may have a configuration that provides heating, or at least it contributes to heating at least part of the formation to a temperature that is sufficient to maintain the oxidation of the hydrocarbons. When this temperature is reached, the oxidized fuel fluid may be replaced with an oxidizing fluid. The oxidizing fluid may oxidize at least a portion of the hydrocarbons in the reaction zone within the formation.

Claims (13)

1. A device for transferring heat to a hydrocarbon containing formation that surrounds a heat supply well that includes an oxidizing fluid source; an oxidizing agent supply conduit located in the wellbore for supplying heat, the conduit having a configuration that delivers an oxidizing fluid from an oxidizing fluid source to the reaction zone during formation operation, the oxidizing fluid being selected so that it oxidizes at least a portion hydrocarbons in the formation near the borehole zone during operation so that heat is generated in the reaction zone; and a pipe for exhausting flue gases located in the wellbore for supplying heat, for passing flue gases through the wellbore for supplying heat with withdrawal from the reaction zone, characterized in that the pipeline for supplying oxidizing agent has a configuration that provides the supply of oxidizing fluid through the reaction zone by diffusion in the gas phase and / or convection. 2. The device according to claim 1, which has a configuration that provides heat transfer from the reaction zone to the selected sections of the formation during operation, mainly due to thermal conductivity. 3. The device according to claim 1, in which the pipelines for supplying an oxidizing agent and for removing flue gases are equipped with pressure control devices that control the pressure in the reaction zone so that a significant portion of the flue gases generated in the reaction zone is discharged to the earth's surface through the pipeline to remove flue gases. 4. The device according to claim 1, in which the oxidant supply pipe and the flue gas exhaust pipe extend coaxially relative to each other from the heating well bore to the hydrocarbon containing formation, wherein the oxidant supply pipe extends from the lower end of the oxidant supply pipe, at least through a significant part of the formation containing hydrocarbons, and the protruding lower part of the oxidant supply pipe is provided with a set of oxidant inlet openings through which the oxidizing agent used l is injected at a transonic or supersonic speed into the annular space between the oxidant supply line and the reaction zone. 5. The device according to claim 1, in which the oxidant supply pipe is an air supply pipe that is equipped with an air compressor, each air supply pipe and a flue gas exhaust pipe may be equipped with a valve that controls the pressure in the annular space between the perforated bottom part of the oxidant inlet conduit and the reaction zone, so that the indicated pressure is practically equal to the pressure in the well in at least part of the surrounding hydrocarbon containing formation odes, and the transition of flue gases to this formation slowed down. 6. The device according to any one of claims 1 to 5, in which the well for supplying heat further comprises an electric heater for transferring heat to the reaction zone. 7. The device according to any one of claims 1 to 5, in which the well for supplying heat further comprises a fuel supply pipe for supplying fuel to the reaction zone. 8. A method of transferring heat to a hydrocarbon containing formation that surrounds a well for supplying heat, which includes introducing an oxidizing agent through an oxidant supply pipe located in a wellbore for supplying heat to the reaction zone in the formation, stimulating an oxidizing fluid to oxidize at least a portion of the hydrocarbons in the formation, close to the wellbore, so that heat and flue gases are generated in the reaction zone; and removing at least a portion of the flue gas through a conduit for discharging flue gases from the reaction zone located in the wellbore for supplying heat, characterized in that the oxidizing fluid supply conduit supplies the oxidizing fluid through the reaction zone by diffusion in the gas phase and / or convection . 9. The method of claim 8, in which the heat released in the reaction zone is transferred mainly due to heat conduction from the reaction zone to the pyrolysis zone in the formation containing hydrocarbons, where hydrocarbons are pyrolyzed. 10. The method according to claim 9, in which one or more production wells passes through a hydrocarbon containing formation at a predetermined distance from the heat supply well, the fluid pressure in the heat supply well and in each production well being regulated so as to stimulate the flow of hydrocarbon pyrolysis products from the pyrolysis zone, through the formation into the production well or wells, and to prevent the flue gas from the reaction zone from passing into any production well. 11. The method of claims 8, 9 or 10, wherein the hydrocarbon containing formation is a coal seam. 12. The method according to claims 8, 9 or 10, wherein the hydrocarbon containing formation is a deposit of tar shale or tar sand. 13. The method according to any one of claims 8 to 12, wherein the well for supplying heat is preheated with an electric heater until the oxidant is supplied to the well for supplying heat.