RU2303693C2 - Coal refining and production - Google Patents

Abstract

FIELD: coal mining, particularly to produce difficult-to-recover and depleted carbons.

SUBSTANCE: method involves heat-treating at least part of carbon formation by supplying heat generated by one or more heaters to heat at least part of carbon formation; producing fluid therefrom; producing at least part of refined coal from treated carbon formation.

EFFECT: possibility to increase coal part category, which results in coal part quality improvement and increased efficiency of coal bed development.

13 cl, 19 dwg, 1 tbl

Description

FIELD OF THE INVENTION

The present invention mainly relates to the production of useful materials from coal. Some embodiments of the present invention generally relate to methods and systems for upgrading hydrocarbons within a coal formation.

Description of the prior art

Hydrocarbons, which are obtained from underground (e.g., sedimentary) formations, are often used as energy carriers, as raw materials and consumer products. The problem of depletion of available hydrocarbon resources and a decrease in the total quality of the obtained hydrocarbons has led to the development of methods for more efficient extraction, processing and / or use of available hydrocarbon resources. To change hydrocarbon-containing materials in the formation development zone, you can use the in-situ conversion method (in the underground formation). It may be necessary to change the chemical and / or physical properties of the hydrocarbon material within the subterranean formation in order to facilitate easier extraction of the hydrocarbon material from the subterranean formation. These chemical and physical changes may include in situ reactions in which recoverable fluids form, composition changes, solubility changes, phase state changes and / or viscosity changes of the hydrocarbon material within the formation. The fluid may be, but is not limited to, a gas, liquid, emulsion, suspension and / or solid particle stream for which the flow characteristics are similar to a liquid stream.

Coal is often mined for use as fuel in a power plant that produces electricity. A significant number of coal formations are unsuitable for economical mining. For example, coal mining from steeply falling coal seams, from relatively thin coal seams (for example, less than about 1 m thick) and / or from deep seams, apparently cannot be considered economically feasible. Deep seams include coal seams that are (or extend) deeper than approximately 914 m (about 3,000 ft) below ground level. The energy conversion efficiency of burning coal for electricity is relatively low compared to fuels such as natural gas. In addition, when coal is burned to produce electricity, significant amounts of carbon dioxide, sulfur oxides, and nitrogen oxides can be generated that are released into the atmosphere.

There are a significant number of attempts to develop methods and systems for the economical production of hydrocarbons, hydrogen and / or other products from the coal formation. However, there are still many coal formations for which economical production of hydrocarbons, hydrogen and / or other products is not possible. Traditional extraction technologies may not be suitable for all formations. In some formations, a material containing many hydrocarbons may be located in layers that are too thin for cost-effective extraction using conventional methods. In an in-situ conversion process, a hydrocarbon-containing material may change in a formation development zone. When exposed to heat, a hydrocarbon material, such as coal, can be converted and / or refined, thereby accelerating the process, which in natural conditions proceeds over a geological period of time.

SUMMARY OF THE INVENTION

The basis of the invention is the task of developing a method for producing refined coal from a carbon formation.

The problem is solved in that the method for producing refined coal from a carbon formation includes processing at least a portion of the carbon formation by supplying heat from at least one or more heaters to heat at least a portion of the carbon formation and production fluids from a carbon formation in which treating a carbon formation increases the category of a portion of coal, and increasing the category at least improves the quality of a portion of coal and the production of at least a portion of the refined coal from a treated carbon formation.

Preferably, the formation is at least partially pyrolyzed.

It is no less preferable that at least a portion of the hydrocarbons in the coal is pyrolyzed.

It is advisable when the production of coal includes the extraction of coal in the form of a powder.

Alternatively, it may be advantageous when the production of coal involves the production of coal in the form of a suspension.

It is necessary that the method further includes supplying a fluid to a portion of the treated formation in order to remove at least a portion of the coal.

The mined charcoal mined includes anthracite.

It should be noted that coal before processing does not contain a significant amount of anthracite, and coal mined contains a significant amount of anthracite.

In the method according to the invention, at least a portion of the obtained refined coal has a carbon content higher than about 87% by weight.

In the method according to the invention, at least a portion of the obtained refined coal has a volatile content of less than about 5 wt.%.

In the method according to the invention, at least a portion of the obtained refined coal has a calorific value of greater than about 25,000 kJ / kg.

In the method according to the invention, at least a portion of the obtained refined coal has a vitrinite reflectance of more than about 2.9%.

It is recommended that at least part of the obtained refined coal be used in steel production.

In one embodiment, heat is introduced into the carbon formation to utilize coal. Hydrocarbons in a carbon formation can be converted into a mixture of relatively high quality hydrocarbon products, hydrogen, and / or other products can be isolated from the formation. Hydrocarbons, hydrogen, and other fluids can be removed from the formation through one or more production wells.

Under the influence of heat on the carbon formation, the properties of coal in the formation can change. In some embodiments, a portion of the carbon formation may be converted to higher grade coal. When exposed to heat, the water content and / or the volatile content of coal in the carbon formation may decrease. Formation fluids (e.g., water and / or volatile compounds) can be removed to the vapor phase. In other embodiments, formation fluids may be removed into the liquid and vapor phases or into the liquid phase. In at least part of the formation, temperature and pressure can be controlled during pyrolysis in order to obtain improved products from the formation. After exposure to heat, coal can be mined from the formation.

Brief Description of the Drawings

The advantages of the present invention may become apparent to those skilled in the art by the following detailed description of preferred embodiments, with reference to the accompanying drawings.

Figure 1 shows a diagram that shows some properties of kerogen resources.

Figure 2 is an illustration of the steps for heating a carbon formation.

Figure 3 shows an arrangement of heat sources.

Figure 4 shows a variant of a heating well.

Figure 5 shows a variant of a heating well.

Figure 6 shows a variant of a heating well.

7 schematically shows a vertical projection of a plurality of heaters branching from one well in a carbon formation.

On Fig shows a variant of a heating well located in a carbon formation.

Figure 9 shows a variant of the location of the heating wells in the carbon formation.

Figure 10 shows a variant of the location of heat sources and production wells in the carbon formation.

Figure 11 presents a top view of a variant of the processing areas formed along the perimeters of the barriers.

12 is a cross-sectional view of an on-site experimental test in the field.

On Fig shows the location of heat sources and wells in an experimental test in the field.

On Fig shows the dependence of temperature on time in an experimental test in the field.

On Fig shows the dependence of temperature on time in an experimental test in the field.

On Fig shows the dependence of the volume of oil produced on time in an experimental test in the field.

On Fig shows the dependence of the volume of gas extracted from the carbon formation from time to time in an experimental field test.

On Fig shows the distribution of the number of carbon atoms in the fluids produced in an experimental test in the field.

On Fig shows the weight fraction (in%) of various fluids produced in the carbon formation at various heating rates in laboratory experiments.

Although this invention is subject to various modifications and alternative forms, specific embodiments thereof are shown by way of examples in the drawings and may be described in detail therein. These drawings cannot be scaled down. However, it should be understood that the drawings and, in addition, the detailed description are not intended to limit the invention to the disclosed specific forms; on the contrary, the invention covers all modifications, equivalents and alternatives that are part of the intent and scope of the present invention, which is defined in the attached claims.

DETAILED DESCRIPTION OF THE INVENTION

The following description mainly relates to carbon formation treatment systems and methods. Such formations can be processed in such a way as to obtain relatively high quality hydrocarbon products, hydrogen, high-grade coal and other products. Under the influence of heat on the carbon formation, part of the carbon formation can be transformed and / or refined, thereby accelerating the process, which in natural conditions proceeds over a geological period of time.

“Hydrocarbons” are molecules that are formed primarily from carbon and hydrogen atoms. “Mixtures containing hydrocarbons” may include hydrocarbons as well as other elements such as (but not limited to) halogens, metal elements, nitrogen, oxygen and / or sulfur. Hydrocarbon containing formations may include kerogen, bitumen, pyrobitumen, oil, natural mineral waxes and asphaltenes. Mixtures containing hydrocarbons can be located inside or near the mineral parent rocks underground. The parent rock may include, but is not limited to, sedimentary rocks, sands, silicites, carbonates, diatomites, and other porous media. "Hydrocarbon-containing fluids" are fluids that contain hydrocarbons. Hydrocarbon-containing fluids may include, engage or be involved in non-hydrocarbon fluids (e.g., hydrogen H ₂ , nitrogen N ₂ , carbon monoxide, carbon dioxide, hydrogen sulfide, water and ammonia).

A “formation” includes one or more hydrocarbon-containing layers, one or more non-hydrocarbon layers overlapping and / or underlying. "Overlapped" and / or "underlying" layers include one or more different types of impermeable materials. For example, overlapped and / or underlying layers may include rocks, shale, mudstone, or moisture-proof carbonate (i.e., impervious carbonate without hydrocarbons). In some embodiments of the in-situ conversion methods, overlapped and / or underlying layers may include hydrocarbon-containing layers or hydrocarbon-containing layers that are relatively impermeable and are not exposed to temperature during processing by in-situ conversion, resulting in significant changes in the characteristics of the hydrocarbon-containing overlapped and / or underlying layers. For example, the underlying layer may contain coal. In some cases, the overlapped and / or underlying layers may have a certain permeability.

"Kerogen" is a solid insoluble hydrocarbon that can be converted by natural decomposition (for example, by diagenesis) and which mainly contains carbon, hydrogen, nitrogen, oxygen and sulfur. An example of kerogen is coal. "Oil" is a fluid containing a mixture of condensable hydrocarbons.

The terms “formation fluids” and “resulting fluids” refer to fluids removed from a carbon containing formation and may include pyrolysis fluids, synthesis gas, mobile hydrocarbons and water (steam). Formation fluids may contain hydrocarbon fluids as well as non-hydrocarbon fluids.

“Number of carbon atoms” refers to the number of carbon atoms in a molecule. The hydrocarbon fluid may include various hydrocarbons having a different number of carbon atoms. A hydrocarbon fluid can be described using the distribution of the number of carbon atoms. The number of carbon atoms and / or the distribution of the number of carbon atoms can be determined using the distribution of the true boiling points and / or gas chromatography.

A "heat source" is any system that provides heat for at least a portion of the formation due to radiation and / or conductive heat conduction. For example, a heat source may include electric heaters, such as an insulated conductor, an elongated element, and a conductor housed in an insulating tube. In addition, the heat source may include heat sources in which heat is generated by burning fuel outside or inside the formation, such as surface burners, gas burners located in the well, distributed flameless combustion regions, and naturally distributed combustion regions. In addition, it is contemplated that in some embodiments, heat supplied or generated by one or more heat sources may come from other energy sources.

Other energy sources can directly heat the formation, or energy can be transferred to transport media that directly or indirectly heat the formation. It should be understood that in one or more heat sources that supply heat to the formation, various energy sources can be used. For example, for this formation, some heat sources can supply heat from electrical resistance heaters, some heat sources can supply heat from combustion, and some heat sources can supply heat from one or more energy sources (for example, chemical reactions, solar energy, wind energy , biomass energy or other renewable energy sources). A chemical reaction may include exothermic reactions (e.g., an oxidation reaction). The heat source may include a heater that supplies heat to an adjacent zone or surrounding heating region, such as a heating well.

A “heater” is any system for generating heat in or near a wellbore. Heaters can be, but are not limited to, electric heaters, burners, combustion areas that interact with or form within a formation (for example, naturally distributed combustion areas), and / or combinations thereof. The term “heat source module” refers to a series of heat sources that form a fragment that repeats, creating a system of heat sources within the formation.

The term “wellbore” refers to a cavity in a formation made by drilling or inserting pipelines into the formation. The wellbore may have a substantially circular cross-section or other cross-sectional shape (for example, a circle, oval, rectangle, triangle, slit, or other constant or non-constant shape). The term “well” and “production” as used herein, when referring to the opening of a formation, may be used interchangeably with the term wellbore.

The term “naturally distributed combustion regions” refers to a heater that uses an oxidizing agent to oxidize at least a portion of the carbon in the formation in order to generate heat, and in which oxidation occurs in close proximity to the wellbore. Most of the combustion products formed in the naturally distributed combustion region are removed through the wellbore.

The term "insulated conductor" refers to any elongated material that is capable of conducting electricity and which is coated, in whole or in part, with an electrically insulating material. The term "self-regulation" refers to the regulation of the radiated power of the heater without any external control.

"Pyrolysis" is the breaking of chemical bonds under the influence of heat. For example, pyrolysis may include the conversion of a compound into one or more other substances only under the influence of heat. In order to cause pyrolysis to occur, heat can be applied to part of the formation.

The terms “pyrolysis fluids” or “pyrolysis products” refer to fluids obtained primarily during the pyrolysis of hydrocarbons. Fluids obtained during the pyrolysis process can be mixed with other fluids in the formation. These mixtures can be considered as pyrolysis fluids or pyrolysis products. As used herein, the term “pyrolysis zone” refers to the volume of the formation in which the interaction occurs to form a pyrolysis fluid.

"Thermal conductivity" is a property of a material that describes the rate at which heat is transferred between two surfaces of the material in a stationary state at a given temperature difference between the two surfaces.

"Condensable hydrocarbons" are hydrocarbons that condense at a temperature of 25 ° C and an absolute pressure of 1 atm. Condensable hydrocarbons may include a mixture of hydrocarbons having a carbon number greater than 4. “Non-condensable hydrocarbons” are hydrocarbons that do not condense at a temperature of 25 ° C. and an absolute pressure of 1 atm. Non-condensable hydrocarbons may include hydrocarbons having a carbon number of less than 5.

"Synthesis gas" is a mixture containing hydrogen and carbon monoxide used to synthesize a number of compounds. Additional components of the synthesis gas may include water, carbon dioxide, nitrogen, methane and other gases. Synthesis gas can be produced using various processes, from various raw materials.

The term "descending" refers to a formation that is inclined downward or deviating from a plane parallel to the earth's surface, under the assumption that this surface is flat (ie, a "horizontal" plane). “Tilt” is the angle that a formation or similar structure forms with a horizontal plane. A "steeply falling" carbon formation refers to a formation containing coal and lying at an angle of at least 20 degrees from the horizontal plane. “Downward slope” refers to a downward direction parallel to the slope of the formation. “Upward slope” refers to an upward direction parallel to the slope of the formation. The term "strike of a formation" refers to the direction or strike of a hydrocarbon material that is perpendicular to the direction of tilt.

"Sediment" is the downward movement of part of a formation relative to the initial elevation of the surface.

The term "layer thickness" refers to the thickness of the cross section of a layer in which the cross section is perpendicular to the plane of the layer.

The term "refinement" refers to improving the quality of hydrocarbons. For example, refining coal can lead to an improvement in the category of coal.

Carbon formations may include kerogen. Kerogen consists of organic matter, which is converted during the ripening process. The ripening process may include two stages: the biochemical stage and the geochemical stage. Typically, the biochemical stage involves the decomposition of organic material by aerobic and / or anaerobic organisms. The geochemical stage usually involves the conversion of organic material due to changes in temperature, as well as significant pressure. During maturation, oil and gas can form when the organic material of kerogen is transformed.

As shown in FIG. 1, the Van Crevelen diagram illustrates the sequence of the kerogen maturation process, which usually proceeds during the geological period when exposed to temperature and pressure. In addition, various natural kerogen deposits are classified on the Van Crevelen diagram. For example, kerogen can be classified into four different groups: type I, type II, type III, and type IV, which correspond to the four areas on the Van Crevelen diagram. The classification of the type of kerogen may depend on the materials preceding the kerogen. Kerogen precursor materials eventually turn into macerals.

"Macerals" are microscopic structures in kerogen. The structure and properties of macerals depend on the type of precursor materials from which they are derived.

Type I kerogen can be classified as alginite, since type I kerogen is formed mainly from a mass of algae. Type I kerogen is formed from sediments obtained in the lake environment. Type II kerogen is formed from organic matter, which is a sediment in the marine environment. Type III kerogen typically includes vitrinitic macerals. Vitrinitis is formed from cell walls and / or wood tissues (e.g., trunks, branches, leaves and roots of plants). Type III kerogen may be present in most humic coals. Type III kerogen is formed from organic material that settles in swamps. Type IV kerogen includes the maceral group of inertinitis. The maceral group of inertinite consists of plant materials, such as leaves, bark, and trunks, which underwent oxidation in the early stages of peat formation during burial diagenesis. Chemically, it is similar to vitrinite, but has a high carbon content and low hydrogen content.

In the Van Crevelen diagram shown in FIG. 1, the atomic ratio of hydrogen to carbon (H / C) is plotted along the ordinate, depending on the atomic ratio of oxygen to carbon (O / C) for various types of kerogen. The Van Crevelen diagram illustrates the sequence of the maturation process for various types of kerogen, which usually occurs during the geological period when exposed to temperature, pressure, and biochemical decomposition. This maturation sequence can be accelerated by heating in place (in the formation) at a controlled speed and / or at a controlled pressure.

If a formation containing kerogen in region 30 or region 32 is selected for in situ conversion, then in situ heat treatment can accelerate kerogen maturation along the routes shown by arrows in FIG. 1. For example, the kerogen in region 30 can turn into the kerogen of region 32 and then, possibly, into the kerogen of region 34. The kerogen in region 32 can turn into the kerogen of region 34. On-site conversion can promote the maturation of kerogen and provide valuable products from kerogen. Region 36 in FIG. 1 may correspond to a region of graphite.

When kerogen undergoes maturation, its composition usually changes due to the removal of volatile substances (such as carbon dioxide, methane and oil) from kerogen. The rank category of kerogen indicates the level of maturation of kerogen. For example, when kerogen undergoes maturation, the kerogen category rises. With an increase in the category of kerogen, the content of volatile substances in it, as well as in the resulting products, decreases. In addition, the moisture content in kerogen usually decreases with increasing categories of kerogen. For higher categories of kerogen, the moisture content can reach a relatively constant value. For higher categories of kerogen, which has undergone significant maturation, such as semi-anthracite and anthracite coal, there is a tendency to an increased carbon content and a lower content of volatile substances, compared to lower-level kerogens such as lignite. In some embodiments, the carbon content of the resulting coal may be higher than about 87% by weight and / or the volatile content may be less than about 5% by weight.

The stages of the carbon formation categories include the following classifications, which are listed in order of increasing category and maturity for type III kerogen: wood, peat, lignite, low bituminous coal, high volatile bituminous coal, medium volatile bituminous coal, non-volatile bituminous coal, semi-anthracite and anthracite. As the category increases, there is a tendency to increase the aromatic nature of kerogen.

For in situ conversion, carbon formations may be selected based on the properties of at least a portion of the formation. For example, a formation may be selected based on its potential, thickness and / or depth (i.e., overlap thickness) of the formation. In addition, the type of fluid obtained from the formation may be a factor in selecting a formation for in situ conversion. In some embodiments, the quality of the fluids produced from the formations can be evaluated prior to processing. Evaluation of the products that can be obtained from the formation can lead to a significant reduction in costs, since it is only necessary to convert in place the formations that will produce the desired products. Properties that can be used to evaluate hydrocarbons in a formation include, but are not limited to: the amount of hydrocarbon liquid that can be obtained from hydrocarbons, probably the specific gravity of the obtained hydrocarbon liquid (in degrees from the American Petroleum Institute), the degree of reflection of vitrinite, and the amount of hydrocarbon gas that can be obtained from the formation; and / or the amount of carbon dioxide and water that can be obtained by in situ conversion.

For example, the degree of reflection of vitrinite often correlates with the atomic ratio of hydrogen to carbon (H / C) in kerogen and the atomic ratio of oxygen to carbon (O / C) in kerogen, as shown by dashed lines in FIG. The Van Crevelen diagram may be useful in selecting a resource for the in-place conversion process. The degree of vitrinite reflection for kerogen in the carbon formation may indicate which fluids will be obtained from the formation when heated. For example, a vitrinite reflectance of from about 0.5% to 1.5% may indicate that a large amount of condensing fluids will be produced from kerogen. In addition, the degree of reflection of vitrinite from about 1.5% to 3% may indicate that kerogen is in region 34. In the case of heating a carbon formation containing such kerogen, a significant amount (for example, the main part) of the fluid obtained by such heating may include methane and hydrogen. This formation can be used to produce synthesis gas if its temperature rises high enough and a synthesis gas is introduced into the formation.

Carbon formations can have a variety of geometries and shapes. Traditional extraction techniques may not be applicable to all formations. In some formations, a high hydrocarbon material may be located in layers that are too thin for cost-effective extraction using conventional methods. Rich carbon formations are typically found in layers having a thickness of between about 0.2 and 8 m. These rich carbon formations may include, but are not limited to, sapropelite coals (bituminous coal, Kennel coal and / or torbanites). These hydrocarbon layers during pyrolysis can produce from about 205 L to 1670 L of oil per metric ton.

In the in-situ conversion process, the hydrocarbon-containing material may change in the processing area of the formation. When exposed to heat, a hydrocarbon material, such as coal, can be converted and / or refined by accelerating the process, which in natural conditions will occur over a geological period of time. Various properties of coal in the processing zone that may vary include, but are not limited to, calorific value, vitrinite reflectance, moisture content, volatiles content (%), permeability, porosity, and the concentration of various components in the coal, such as sulfur and / or carbon content.

When a carbon formation is heated, coal can undergo several stages of heating, as shown in FIG. As an example, figure 2 shows the dependence of the yield (BOE - barrel of oil equivalent per 1 ton) (along the ordinate axis) of the fluid from the carbon formation from the temperature of the formation (along the abscissa).

Methane desorption and water evaporation occur during heating in region 38. Heating the formation in region 38 can be carried out as quickly as possible. For example, during initial heating of a formation, hydrocarbons in the formation may desorb absorbed methane. Desorbed methane can be extracted from the formation. If the carbon formation is further heated, water may evaporate from the carbon formation. In some carbon formations, water may occupy between approximately 10 and 50% of the pore volume in the formation. In other formations, water may occupy more or less of the pore volume. Typically, water evaporates in the formation at a temperature between 160 and 285 ° C at an absolute pressure of about 6 to 70 bar (0.6-7 MPa). In some embodiments, evaporated water may cause changes in the wettability of the formation and / or an increase in pressure in the formation. Changes in wettability and / or pressure increase can affect the pyrolysis process or other processes in the formation. In certain embodiments, evaporated water may be removed from the formation. In other embodiments, evaporated water may be used to control steam withdrawal and / or distillation in or out of the formation. Removing water from the formation and increasing pore volume in the formation can increase the storage space for hydrocarbons within the pore volume.

After heating in region 38, the formation can be heated higher so that the temperature inside the formation reaches (at least) the initial pyrolysis temperature (for example, the temperature at the lower edge of the temperature range shown as region 40). Hydrocarbons within the formation may be pyrolyzed in region 40. The pyrolysis temperature range may vary depending on the type of hydrocarbons within the formation. The pyrolysis temperature range may include temperatures between about 250 and 900 ° C. To obtain the desired products, the pyrolysis temperature range can extend only in part of the general pyrolysis temperature range. In some embodiments, the temperature range of the pyrolysis to obtain the desired products may include temperatures between about 250 and 400 ° C. If the temperature of hydrocarbons in the formation slowly rises in the temperature range from about 250 to 400 ° C, the formation of pyrolysis products can be almost completed when the temperature reaches 400 ° C. Heating a hydrocarbon containing formation using a variety of heat sources can lead to the establishment of temperature gradients around the heat sources and to a slow increase in the temperature of hydrocarbons in the formation in the pyrolysis temperature range.

In some embodiments of the in-situ conversion process, the temperature of the hydrocarbons that will be pyrolyzed cannot rise slowly in the temperature range of about 250 to 400 ° C. Hydrocarbons in the formation can be heated to the desired temperature (for example, approximately 325 ° C). Other temperatures may be selected as the desired temperature. The superposition of heat from heat sources can provide a relatively quick and efficient achievement of the desired temperature in the formation. In order to maintain the temperature in the formation practically at the desired level, it is possible to control the energy supply to the formation from heat sources. The temperature of hydrocarbons can be maintained practically at the desired level until the pyrolysis decays, when the production of the desired fluids from the formation becomes uneconomical.

Fluids including pyrolysis fluids may be produced from the formation. Pyrolysis fluids may include, but are not limited to, the following: hydrocarbons, hydrogen, carbon dioxide, carbon monoxide, hydrogen sulfide, nitrogen, ammonia, water, and mixtures thereof.

As the temperature of the formation increases, the amount of condensing hydrocarbons in the fluids formed in the formation tends to decrease. At high temperatures, the formation can mainly produce methane and / or hydrogen. If the carbon formation is heated over the entire pyrolysis temperature range, the formation can produce only a small amount of hydrogen near the upper pyrolysis temperature range. After all available hydrogen has been recovered, the formation typically provides a minimal amount of fluid.

After the pyrolysis of hydrocarbons, a significant amount of carbon and some hydrogen may still be present in the formation. In some embodiments, a carbon formation may be developed after the synthesis gas generation is completed during heating of region 42. Treatment of the carbon formation may cause the remaining coal in the formation to mature in the direction of anthracite coal. In some embodiments, the material extracted from the formation may be used in the field of metallurgy, for example, as a fuel to achieve high temperature in steel production. The pyrolysis of the carbon formation may increase the category of coal. After pyrolysis, coal is converted and acquires the characteristics of anthracite. The spent carbon formation may have a thickness of 30 m or more. In comparison, typical thicknesses of formations that are typically developed for metallurgical purposes are approximately 1 m or less.

For example, coal within the processing area may be considered bituminous coal before processing. Under the influence of heat, coal can be converted to produce anthracite coal. Anthracite coal has a reduced moisture content, increased calorific value and a higher carbon content. In some embodiments, anthracite coal may be used in metallurgical production. Typically, anthracite coal is found in thin coal seams several meters thick. As a result of the on-site conversion process, it is possible to obtain an anthracite layer from a thick layer of bituminous coal, which is thicker than the layer formed under natural conditions.

Converted in-place coal can have high permeability and porosity. At least a portion of the coal heated using the in-situ conversion process, in some embodiments, may have several faults. In some cases, at least a portion of the coal may be loose or in powder form. In some embodiments, the coal processed during the on-site conversion process can be easily removed from the formation using an underground automated system or robotics, the coal being mined as a powder or slurry. For example, a hydraulic monitor may be used to remove at least a portion of the coal in suspension. In some embodiments, the overlap may be removed using earthmoving and transporting machines after sufficient time has elapsed so that the treated formation can cool to a temperature at which safe operation is possible. In some embodiments, tunnels may be constructed for coal that has been processed using an in-situ conversion process. For mining and removal of coal, you can use traditional mining equipment.

Coal mined in powder or suspension form can be used in various processes that include (but are not limited to) directly burning coal on the surface for use as an energy source and / or suspending and transporting coal for sale as energy fuel. For example, a first fluid may be fed into a portion of a formation that has been processed using an in-situ conversion process. The first fluid may contain water. The first fluid may break and / or grind the coal in the formation into relatively small pieces. These relatively small pieces can be combined with the first fluid to form a slurry that can be removed or recovered from the formation. This slurry can be processed in a surface installation in order to separate the first fluid from relatively small lumps of coal. Lumps of coal can be processed in a surface installation, in cleaning or extraction processes.

Such carbon can be used as an activated carbon filter in order to remove components from various water and / or air flows in the process module of the conversion process in place and / or outside the module. Alternatively, coal can be used as an adsorbent (which can further improve the fuel characteristics of coal), followed by burning coal for energy production, as an intermediate in the production of dyes (e.g. anthraquinone), as fuel and / or in metallurgical processes. Coal processing in an in-situ conversion process can convert coal in such a way that the economic value of coal increases and / or the costs associated with coal mining are reduced.

During the pyrolysis process, the total energy content in the fluids extracted from the carbon formation can remain almost constant. During pyrolysis at relatively low formation temperatures, a significant portion of the resulting fluid may be condensable hydrocarbons that have a high energy content. However, at elevated pyrolysis temperatures, a smaller portion of the formation fluid may include condensable hydrocarbons. More non-condensing fluids can be obtained from the formation. The energy content per unit volume of fluid produced may decrease slightly during the formation of predominantly non-condensing formation fluids.

Heating a carbon formation may include supplying a significant amount of energy to heat sources located within the formation. The carbon formation may also contain some water. A significant portion of the energy that was initially supplied to the formation can be used to heat water within the formation. The initial rate of temperature rise may decrease due to the presence of water in the formation. Excessive heat and / or time may be required to heat the formation having a high moisture content to a temperature sufficient to pyrolyze hydrocarbons in the formation. In some embodiments, it is possible to prevent water from entering the formation, which will undergo in situ conversion. The formation that will undergo in situ conversion may have a low initial moisture content. The initial moisture content in the formation may be less than about 15% by weight. Some formations that will undergo in situ conversion may have an initial moisture content of less than about 10% by weight. Other formations that will undergo in situ conversion may have an initial moisture content of greater than about 15% by weight. For formations with an initial moisture content of more than about 15% by weight, heating to the pyrolysis temperature may require significant energy expenditures to remove the water that was originally in the formation.

A carbon formation may include multiple layers. Such layers may contain layers containing hydrocarbons, as well as layers not containing hydrocarbons or having a relatively small amount of hydrocarbons. Conditions within the formation may determine the thickness of the hydrocarbon and non-hydrocarbon layers in the carbon formation. The carbon formation to be converted in situ can typically include at least one layer containing hydrocarbons and having a thickness sufficient to economically produce fluids in the formation. The potential of the hydrocarbon containing layer may serve as a factor in assessing the feasibility of processing the formation by in situ conversion. A thin and rich hydrocarbon layer can provide significantly more valuable hydrocarbons than a much thicker, but less rich hydrocarbon layer. For hydrocarbon production, a formation that is thick as well as rich is desirable.

Figure 3 shows a schematic diagram of an embodiment of a portion of an in situ conversion system for processing a carbon formation. Heat sources 44 may be located within at least a portion of the carbon formation. Heat sources 44 may include, for example, electric heaters such as insulated conductors, conductor heaters in an insulating tube, surface burners, flameless distributed combustion regions and / or naturally distributed combustion regions. In addition, heat sources 44 may include other types of heaters. Heat sources 44 may provide heat to at least a portion of the carbon formation. In some embodiments, heat may be delivered to the first part of the formation and transferred to the second part of the formation (e.g., a pyrolysis zone). Energy can be supplied to the heat sources 44 through the supply lines 46.

Supply lines 46 may be structurally different, depending on the type of heat sources that will be used to heat the formation. Supply lines 46 for heat sources 44 may supply electricity to electric heaters, may transport fuel in a combustion area, or may transport heat exchange fluid that circulates within a formation.

Production wells 48 may be used to remove fluid from the formation. Fluids obtained from production well 48 may be transported through pipe manifold 50 to processing device 52. In addition, formation fluids can be obtained from heat sources 44. For example, fluids can be obtained from heat sources 44 in order to regulate the pressure inside the formation, next to the heat source. Fluid obtained from heat sources 44 may be transported via pipelines or pipe system to a pipe manifold 50, or fluid obtained may be transported via pipelines or pipe system directly to a processing device 52. The processing device 52 may include separation units, reaction units, refining units, fuel cells, turbines, storage tanks and other systems and units for processing the resulting formation fluids.

The in-situ conversion system for hydrocarbon processing may include barrier wells 54 (wells indicated at 54, in some embodiments, may be dewatering wells, frozen wells, capture wells, isolation wells, and / or other types of barriers). In some embodiments, the barrier wells 54 may be vacuum wells through which water is removed and / or liquid is prevented from flowing into the portion of the hydrocarbon containing formation to be heated or into the heated formation. A plurality of barrier wells 54 may surround all or part of the formation that will be heated. In the embodiment of FIG. 3, wells are shown that extend along only one side of the heat sources 44, but barrier wells 54 typically surround all used heat sources or sources that will be used to heat the formation.

In some embodiments, barrier wells 54 may be dewatering wells. In some embodiments, the treatment zone may be surrounded by two or more rows of dewatering wells. In one embodiment, the pressure drop between successive rows of dewatering wells can be minimized (for example, kept relatively low or close to zero) to create a “low or no flow” boundary between the rows.

In certain embodiments, wells that were first used for one purpose can subsequently be used for one or more other purposes, thereby reducing capital costs and / or shortening the time required to complete certain tasks. For example, production wells (and in some cases heating wells) can first be used as dewatering wells (for example, before heating starts and / or when starting the initial heating). In addition, in some cases, dewatering wells can later be used as production wells (and in some cases as heating wells). In fact, dewatering wells can be placed or designed so that such wells can subsequently be used as production wells and / or heating wells. Heating wells can be placed or designed so that such wells can subsequently be used as production wells and / or dewatering wells. Production wells may be located or designed so that such wells can subsequently be used as dewatering wells and / or heating wells. Similarly, injection wells may be wells that were first used for other purposes (for example, for heating, operation, dehydration, control, etc.), and subsequently injection wells may be used for other purposes. Similarly, control wells may be wells that were first used for other purposes (for example, for heating, operation, dewatering, injection, etc.), and subsequently control wells may be used for other purposes.

In some embodiments, heat sources may be located inside a heating well formed within a carbon formation. A heating well may include a hole through the overlap of the formation. A heating well may extend inward or through at least (one) one hydrocarbon layer of the formation. In a carbon formation, the hydrocarbon layer is typically a coal layer. The embodiment of the heating well 56 shown in FIG. 4 may include a hole in the hydrocarbon layer 58, which may be helical or helical. A spiral heating well may increase contact with the formation compared to a heater located vertically. The spiral heating well may provide an expansion space that prevents buckling or other forms of damage when the heating well is heated or cooled. In some embodiments, the heating well may include substantially straight portions passing through the overlap 60. Using a substantially straight section of the heating well passing through the overlap 60 can reduce heat loss in the overlap and reduce the cost of the heating well 56.

Figure 5 shows an embodiment of a heat source having a U-shape. The "sleeves" of this shape may be wider or narrower, depending on the specific characteristics of the heating well and formation. In some embodiments, the first part 62 and the third part 64 of the heating well 56 may be located substantially perpendicular to the upper portion of the hydrocarbon layer 58. In addition, the first part and the third part of the heating well may extend almost vertically through the overlap 60. The second part 66 of the heating well 56 may pass almost parallel to the upper surface of the hydrocarbon layer.

In some cases, multiple heat sources (e.g., 2, 3, 4, 5, 10 heat sources or more) may come out of a heating well. As shown in FIG. 6, heat sources 44, 44 ′ and 44 ″ pass through the overlap 60 to the hydrocarbon layer 58 from the heating well 56. Multiple wells exiting from one wellbore may be used when due to the situation on the surface ( for example, for reasons of aesthetics, the use of land on the surface and / or the adverse condition of the soil near the surface), concentration of drilling platforms in a small area is desirable. For example, in areas with frozen or swampy soil, in terms of cost savings, it may be more efficient to have a minimum number of drilling platforms located on a separate site.

In some embodiments, the first portion of the heating well may extend from the surface of the earth, through the overlap, to the carbon formation. The second part of the heating well may include one or more heating wells in the carbon formation. These one or more heating wells in the carbon formation may be located at different angles. In some embodiments, the at least one heating well may be substantially parallel to the boundary of the carbon formation. In other embodiments, the at least one heating well may be located substantially perpendicular to the carbon formation. In addition, at least one or more heating wells may be located at an angle between perpendicular and parallel to the layer in the formation.

Figure 7 shows a General view from the elevation of multiple heat sources branched from a single opening. In some embodiments, heat sources 44 can be used to generate heat along the length of the heater inside the vertical opening 68 and horizontal openings 70. In other embodiments, heat sources 44 can be used to generate heat only inside horizontal openings 70. In some embodiments, the heat intensity generated by heat sources 44 may vary along the length of the source and / or vary between vertical opening 68 and horizontal openings 70. For example, and heat gauges 44 can generate less heat in vertical opening 68 and can generate more heat in horizontal openings 70. It may be advantageous to have at least one slight heating inside vertical opening 68. This may keep fluids extracted from the formation in the steam phase in the product line 72 and / or may improve the quality of the resulting fluids within the production well. Due to the fact that the product pipeline 72 and heat sources 44 are mounted in the formation through a single opening 68, the costs associated with the formation of openings in the formation and installation of production equipment and heaters inside the formation can be reduced.

One or more vertical openings 68 may be formed in the hydrocarbon layer 58. Each of the vertical openings 68 may be located along a single plane in the hydrocarbon layer 58. Horizontal openings 70 may extend in a plane substantially perpendicular to the vertical openings 68. In some embodiments, additional horizontal the holes may be in a plane below the horizontal holes shown. The number of vertical openings 68 and / or the intervals between vertical openings can be determined, for example, by the desired heating rate or the desired level of productivity. In some embodiments, the gaps between the vertical openings can be from about 4 m to 30 m. Longer or shorter gaps can be used in accordance with the specific needs of the formation. The length of the horizontal holes 70 can be up to about 1600 m. However, the length of the horizontal holes 70 can vary, for example, depending on the maximum installation costs, the area of the hydrocarbon layer 58 or the maximum length of the heating heater.

In an embodiment of the in situ conversion process, a formation having one or more thin hydrocarbon layers may be treated. In some embodiments of the in-situ conversion process, such formations can be processed using heat sources that are located almost horizontally within and / or adjacent to a thin hydrocarbon layer or thin hydrocarbon layers. A relatively thin hydrocarbon layer may be located at a considerable depth below the surface of the earth. For example, a formation may have an overlap of up to about 650 m in depth. The cost of drilling a considerable amount of a large number of practically vertical wells within the formation can be significant. The horizontal arrangement of heaters within these formations may be advantageous in order to heat most of the formation to a length of approximately 1,600 m. The use of horizontal heaters may reduce the number of vertical wells that are needed to accommodate a sufficient number of heaters within the formation.

The angle of inclination of the hydrocarbon layer 58 relative to the upper surface of the earth 74 may be different. For example, the hydrocarbon layer 58 may be inclined or steeply relative to the upper surface of the earth 74, as shown in FIG. In some embodiments, the hydrocarbon layer may extend almost horizontally relative to the top surface of the earth. When using currently available production methods, economically feasible development of steeply dipping hydrocarbon layers seems impossible.

An inclined or relatively steeply falling hydrocarbon layer may be involved in the in situ conversion process. A number of production wells 48 may be located near the highest portion of the inclined hydrocarbon layer of the carbon formation. A series of heating wells 56 may be located in the hydrocarbon layer 58. A series of heating wells 56 may be used to heat the treatment area 76. Initially, the upper portion of the hydrocarbon layer 58 may be processed. Thermal energy from the heating well 56 may cause pyrolysis of coal to form hydrocarbon vapors that are removed from productive production wells 48. When production from the upper part of the formation decreases, the deeper parts of the formation may heat up to the pyrolysis temperature. The resulting hydrocarbon vapors can pass through previously pyrolyzed coal. High permeability due to pyrolysis and fluid production from the upper part of the formation can provide vapor phase transport with minimal pressure loss. Transporting the vapor phase of the fluid obtained in the formation may eliminate the need for deep production wells, in addition to production wells. The number of production wells needed to form a formation can be reduced. Reducing the number of production wells needed for production can increase the cost-effectiveness of the in-place conversion process.

A wellbore can be obtained by directional drilling, structurally directional drilling, drilling with a controlled engine and an acceleration meter, using shock technology and / or ultrasonic drilling technology. The method used to obtain the wellbore can be determined taking into account a number of factors. These factors may include, but are not limited to, field availability, wellbore depth, overlap properties, and properties of the hydrocarbon containing layer or layers.

An embodiment of a plurality of heating wells 56 formed in hydrocarbon layer 58 is shown in FIG. 9. The hydrocarbon layer 58 may be a steeply falling layer. One or more heating wells 56 may be located in the formation so that two (or more) heating wells are substantially parallel to each other and / or such that at least one heating well is substantially parallel to the boundary of the hydrocarbon layer 58 s non-hydrocarbon layer. For example, one or more heating wells 56 may be formed in the hydrocarbon layer 58 by a magnetically directed method. An example of a magnetically directed method is described in US patent No. 5676212 (Kuckes). Magnetically directed drilling may include drilling a heating well 56 parallel to an adjacent heating well. This adjacent well may be pre-drilled. In addition, magnetically directed drilling may include drilling directed by sensors and / or with a magnetic field generated in an adjacent heating well. For example, a magnetic field can be created in a neighboring heating well by passing current in an insulated conductive line located in a neighboring heating well.

In an embodiment of the in-situ conversion process, the degree of heating can be adjusted so as to minimize the cost of heating the selected section. These costs may include, for example, the cost of energy supplied and the cost of equipment. In some embodiments, the costs associated with heating the selected section can be minimized by reducing the degree of heating when the costs associated with heating are relatively high, and by increasing the degree of heating when the costs associated with heating are relatively low. For example, a heating degree of about 330 W / m can be used when the corresponding costs are relatively high, and a heating degree of about 1640 W / m can be used when the corresponding costs are relatively low. In some embodiments, the degree of heating may vary between about 300 and 800 W / m when the corresponding costs are relatively high, and between about 1000 and 1800 W / m when the corresponding costs are relatively low. The costs associated with heating can be relatively high during peak periods of energy use, such as during the daytime. For example, energy consumption during the hot season can be high during the daytime due to energy consumption for air conditioning. A period of low energy consumption can be, for example, night time or the end of the week when energy consumption is reduced. In this embodiment, the degree of heating can vary from a higher degree of heating during a period of low energy consumption, such as at night, to a lesser degree of heating during a period of high energy use, such as during daytime.

As shown in FIG. 3, in addition to heat sources 44, one or more production wells 48 can usually be located within a portion of the carbon formation. Formation fluids can be produced through production well 48. In some embodiments, production well 48 may include a heat source. This heat source can heat part of the formation in or near production well 48 and allow for the removal of the vapor phase of the fluid. The need to pump liquids from a production well at a high temperature can be reduced or eliminated. Limiting or eliminating pumping at high temperature fluids can significantly reduce operating costs. Providing heating in or near the production well can: 1) prevent condensation and / or reflux of the produced fluid when such a medium moves in the production well near the overlap, 2) increase the heat input to the formation and / or 3) increase the formation permeability in the production well or near it. In some embodiments of the in-situ conversion process, the amount of heat supplied to the production well is significantly less than the amount of heat supplied to the heat sources that heat the formation.

Embodiments of a production well may include valves that modify, maintain, and / or control pressure in at least a portion of the formation. Production wells may be a casing well. Production wells may have product filters or perforated casing near the production area. In addition, production wells may be surrounded by sand, gravel or other sealing materials, close to the production area.

During on-site conversion, production wells can be operated so that production wells are under less pressure than other parts of the formation. In some embodiments, a vacuum is maintained in production wells. Maintaining reduced pressure in production wells can prevent the migration of fluids from the formation to the outside, from the field of treatment in place.

Figure 10 shows a diagram of heat sources 44 and production wells 48, which can be used to process the carbon formation. Heat sources 44 can be located in a block of heat sources, such as a triangular fragment 82. However, heat sources 44 can be located in various fragments, which include, but are not limited to: squares, hexagons, and other polygons. This fragment may include regular polygons that provide uniform heating of the formation in which the heat sources are located. In addition, this fragment may be a linear outline of the arrangement. Typically, the linear arrangement of the arrangement includes a first linear arrangement of heating wells, a second linear arrangement of heating wells and production wells, or a linear arrangement of production wells between the first and second linear arrangement of heating wells.

Using some of the options for implementing the on-site conversion process, it is possible to economically process formations that were previously considered uneconomical for production. The recovery of hydrocarbons from formations that were previously considered uneconomical for production was made possible due to an unexpected increase in thermal conductivity and thermal diffusion, which can be used during the thermal conversion of hydrocarbons inside the formation under the influence of inductive and / or radiative heating of part of the formation. The unexpectedness of the results is illustrated by the fact that it follows from the prior art that certain carbon formations, such as coal, have relatively low values of thermal conductivity and thermal diffusion when heated. For example, in State Report No. 8364 of JMSinger and RPТуе, entitled "Thermal, mechanical and physical properties of selected coals and cokes". Department of the Interior, U.S. Mining Bureau (1979), authors cite thermal conductivity and thermal diffusion values for four bituminous coals. This report includes the dependences of thermal conductivity and thermal diffusion on temperature, from which it follows that these indicators have relatively low values up to 400 ° C (for example, thermal conductivity is about 0.2 W / (m.K) or lower, and thermal diffusion - approximately 1.7 · 10 ^-3 cm ² / s). This State Report states that "coal and coke are excellent thermal insulators."

In some embodiments of the in-situ conversion process, hydrocarbon-containing resources (e.g., coal) can be processed so that the thermal conductivity and thermal diffusion are significantly higher (e.g., thermal conductivity of about 0.5 W / (mK) and higher, and thermal diffusion is approximately 4.1 · 10 ^-3 cm ² / s), compared with the values expected from consideration of published literature, such as State Report No. 8364. If the carbon formation is involved in the in situ conversion process, then coal does not behave as an “excellent thermal insulator”. On the contrary, heat can and does transfer and / or diffuse into the formation at a significantly higher (and better) speed than the rate expected in accordance with published literature, resulting in significantly improved economic feasibility of heat treatment of the formation.

In an embodiment of the in situ conversion process, heating a portion of the carbon formation in situ to a temperature lower than the upper pyrolysis temperature may increase the permeability of the heated portion of the formation. Permeability may increase due to the formation of thermal fractures inside the heated portion. Thermal faults can be formed due to thermal expansion of the formation and / or local increase in pressure due to the evaporation of liquid substances (for example, water and / or hydrocarbons) in the formation. As the temperature of the heated portion of the formation increases, the water in it may evaporate. Evaporated water may exit and / or be removed from the formation. Removing water from the formation can also increase the permeability of the heated portion of the formation. In addition, the permeability of the heated portion can also increase due to the loss of mass from the formation, resulting in the formation of fluid pyrolysis products in the formation. Fluid pyrolysis products can be removed from the formation using production wells.

Heating the formation using heat sources located in the formation can provide almost uniform permeability to the heated portion of the carbon formation. Almost uniform permeability can prevent the formation of fluid channels in the formation and provide products from virtually all parts of the heated formation. The determination of the value (for example, by calculation or estimation) of the permeability of any selected part in a formation having practically uniform permeability cannot change more than 10 times per average estimate of the permeability of this selected part.

The permeability of a selected portion within the heated portion of the carbon formation can rapidly increase when this selected portion is heated due to conductivity. The permeability of the impermeable carbon formation prior to treatment may be less than about 0.1 milli Darcy (9.9 x 10 ^-17 m ² ). In some embodiments, by pyrolyzing at least a portion of the carbon formation, the permeability within this selected portion can increase to more than about 10 milli Darcy, 100 milli Darcy, 1.0 Darcy, 10, 20, or 50 Darcy. The permeability of this selected portion can increase by more than about 100, 1000, 10,000, 100,000 times or more.

In some embodiments of the on-site conversion process, the application (eg, overlapping) of heat fluxes from one or more heat sources can result in substantially uniform heating of a portion of the carbon formation. Since there is usually a temperature gradient when heating formations, which has a maximum value near heat sources and decreases with increasing distance from heat sources, “almost uniform” heating means heating when the temperature in most sections does not differ by more than 100 ° C from estimates of the average temperature in most selected sections (volume) that are processed.

The removal of hydrocarbons from the formation during the in-situ conversion process can occur on a microscopic scale, as well as on a macroscopic scale (for example, through production wells). Hydrocarbons can be removed from micropores within a portion of the formation by heating. Micropores can generally be defined as pores having a cross-sectional size of approximately less than 1000 Angstroms (100 nm). The removal of solid hydrocarbons can lead to an almost uniform increase in the porosity of the selected section within the heated portion of the formation. The heating of a part of the carbon formation can lead to an almost uniform increase in the porosity of the selected section within the heated part. The term "almost uniform porosity" means that the determination (for example, by calculation or evaluation) of porosity in any selected section does not differ by more than 25% from the average porosity in such a selected part.

The physical characteristics of a portion of the carbon formation after pyrolysis may be similar to the characteristics of the porous layer. The physical characteristics of the formation subjected to the in-situ conversion process may differ significantly from the physical characteristics of the carbon formation subjected to the injection of gases that burn hydrocarbons in order to heat the hydrocarbons and / or the formations subjected to steam injection. Gases injected into undeveloped or fractured formations can form channels throughout the formation. These gases can be unevenly distributed throughout the formation. In contrast, gas injected into a portion of a carbon formation subjected to an in-situ conversion process can easily and almost uniformly contact carbon and / or hydrocarbons remaining in the formation. Gases produced by heating hydrocarbons can travel a considerable distance within the heated portion of the formation with minimal head loss.

Transporting gases in the formation over a considerable distance can be particularly beneficial in reducing the number of production wells needed to extract fluid from the formation. The first part of the hydrocarbon containing formation may be involved in the in situ conversion process. The volume of the formation involved in the in situ conversion process can be expanded by heating the adjacent parts of the carbon formation. Formation fluid obtained in adjacent parts of the formation may be produced from production wells in this first part. If necessary, several additional production wells may be mounted in adjacent parts of the formation, but such production wells may have large separation distances. The ability to transport fluids in the formation over a considerable distance can be beneficial for processing steeply falling carbon formations. Production wells may be located in the upper part of the deviated development. Heat sources may follow the slope of the formation. The upper part can be heat treated by activating part of the heat sources in the upper part of the formation. The adjacent parts of the steeply falling formation can be subjected to heat treatment, after processing its upper part; this increases the permeability of the formation, so that fluids in the lower parts of the formation can be extracted from the upper parts.

In one embodiment, hydrocarbon production from the formation is prevented until at least a portion of the hydrocarbons in the formation are pyrolyzed. Hydrocarbons can be produced from the formation at a time when the mixture acquires a given quality (for example, specific gravity in degrees API, hydrogen concentration, aromatic hydrocarbon content, etc.). In some embodiments, predetermined quality indicators include specific gravity in degrees API, at least at temperatures of about 20, 30, or 40 ° C. Preventing production until at least a portion of the hydrocarbons undergo pyrolysis can lead to an increase in the conversion of heavy hydrocarbons to light hydrocarbons. Preventing initial production can minimize the production of heavy hydrocarbons from the formation. When producing a significant amount of heavy hydrocarbons, expensive equipment is required and / or the service life of the production equipment is reduced.

When hydrocarbon production from the formation is prevented, pressure tends to increase with increasing temperature in the formation due to thermal expansion and / or phase transformations of heavy hydrocarbons and other fluids (eg, water) in the formation. It may be necessary to maintain the pressure within the formation below a predetermined level to prevent unwanted production, cracking of the overlap or bed and / or coking of hydrocarbons in the formation. The target pressure may be a lithostatic or hydrostatic pressure of the formation. For example, a predetermined pressure may correspond to approximately 15 MPa, or in some embodiments, a predetermined pressure may be approximately 3.5 MPa. Formation pressure can be controlled by controlling the degree of production from production wells in the formation. In other embodiments, the pressure in the formation can be controlled by depressurizing through one or more discharge wells in the formation. Unloading wells may be wells with heat sources or stand-alone wells introduced into the formation.

Fluid is removed from the formation through discharge wells and can be directed to a surface treatment device. The production of at least a portion of the hydrocarbons from the formation can prevent the pressure in the formation from rising above a predetermined value.

In the process of slow heating, condensed hydrocarbon liquids having a specific gravity in degrees API in the range of 22 to 50 ° (0.9328 to 0.7796) and an average molecular weight of about 150 to 250 g / g · mol can be obtained.

In some embodiments, the migration of formation fluids to or from the treatment area can be prevented by the use of barriers. Barriers may include, but are not limited to, naturally occurring barriers (e.g., overlays and / or underlying layers), frozen barrier zones, low temperature barrier zones, cemented walls, sulphurous wells, dewatering wells, injection wells, a barrier formed by the gel formed in the formation , a barrier formed by the deposition of salts in the formation, and / or combinations thereof. Barriers can limit the processing area. Alternatively, part of the treatment area may be provided with barriers.

Figure 11 shows a variant of the processing areas 76 bounded by a perimeter barrier 84. The perimeter barrier 84 defines a limited amount of formation that will be processed during the on-site conversion process. The limited volume of the formation is known as treatment area 76. Definition of a limited formation volume, i.e. the area to be processed can provide easier regulation of the process conditions within a limited volume.

The perimeter barrier 84 may include mounted parts and parts of a formation of natural origin. Parts of the natural formation that form part of the perimeter barrier may include substantially impermeable layers of the formation. Examples of perimeter barriers of natural origin include floors and underlying layers. Mounted parts of the barrier 84 around the perimeter can be mounted if necessary, in order to determine the individual area 76 of the processing. In the in situ conversion process, wells 86 may be located within processing areas 76. Wells 86 of the in-situ conversion process may include heat sources, production wells, dewatering wells of the treatment area, control wells, and other types of wells that are used in the in-situ conversion process.

Different processing areas 76 may separate sections of common barriers in order to minimize the length of the barrier 84 around the perimeter that needs to be formed. A perimeter barrier 84 can prevent fluid from migrating to the treatment area 76, which is involved in the in-situ conversion process. It is advisable when the perimeter barrier 84 can prevent the migration of water from the formation into the treatment area 76. Formation water typically includes water and material dissolved in water (e.g., salts). If water is allowed to migrate from the formation to the treatment area 76 during the in-place conversion process, the formation water can lead to an increase in the operating costs of this process by adding additional energy costs associated with the removal, isolation and treatment of additional water in the fluid obtained in formations. When a significant amount of water migrates from the formation to the treatment area, the temperature rise within portions of the treatment area 76 to the desired temperature may be slowed down.

For certain types of perimeter barriers 84 (e.g., frozen barriers) between adjacent treatment areas 76, it is possible to involve adjacent treatment areas in various in-place conversion processes. For example, the first treatment area may be pyrolyzed, the second treatment area adjacent to the first treatment area may be subjected to synthesis gas generation, the third treatment area adjacent to the first treatment area and / or the second treatment area may be involved mining in place. Technological conditions in different areas of processing may differ in terms of temperature, pressure, productivity, heat input rate, etc.

In some formations, the hydrocarbon containing layer that will be involved in the in situ conversion process is located in that part of the formation that is permeable and / or fractured. In the absence of a perimeter barrier 84, the formation fluid generated during the in-situ conversion process could leave the volume of the formation that is being processed. The fluid flow of the formation from the volume of the formation that is being processed may inhibit the ability to maintain the desired pressure within a portion of the treated formation. Thus, determining the limited volume of the formation to be processed using a perimeter barrier 84 can provide pressure control within the limited volume. Regulation of the amount of fluid removed from the treatment area 76 through unloading wells, production wells and / or heat sources can provide pressure control within the treatment area. In some embodiments, the discharge wells are perforated casing strings located within or adjacent to the wellbores of the heat sources that have sealed casing strings, such as distributed flameless combustion regions. The use of perimeter barriers of the same type (for example, frozen barriers and cemented walls) can provide pressure control in individual processing areas 76.

During the in-situ conversion process, heat introduced into the formation can cause fractures within processing areas 76. Some faults may propagate in the direction of the perimeter of the processing region 76. A propagating fault may cross the aquifer, which will result in formation water entering the treatment area 76. The formation water entering the treatment area 76 can prevent the formation temperature from rising under the influence of heat sources, in part of the treatment area, to a level that is significantly higher than the evaporation temperature of the water entering the formation. In addition, faults can provide for the migration of fluid generated during the in-situ conversion process from processing area 76.

A perimeter barrier 84 around processing region 76 may limit the influence of a propagating fault on the in-situ conversion process. In some embodiments, perimeter barriers 84 are located far enough away from the treatment area 76 so that faults that develop in the formation do not affect the perimeter barrier integrity. Perimeter barriers 84 may be located 10, 40, or 70 m away from well 86 of the in-situ conversion process. In some embodiments, perimeter barriers 84 may be located adjacent to the treatment area 76. For example, a frozen barrier formed by frozen wells may be located near heat sources, production wells, or other wells. Wells 86 of the in-place conversion process can be located at a distance of less than 1 m from the frozen wells, although at greater distances it is possible to appropriately limit the effect on the wells of the conversion process in place of the frozen barrier and to limit the effect of heating on the frozen barrier.

Perimeter barriers can be used to reverse control pulses and / or to ensure that the on-site conversion process does not significantly affect areas adjacent to the treatment area (e.g., groundwater level or other areas that are sensitive to the environment). The perimeter formation inside the barrier can be processed using an in-place conversion process. The perimeter barrier can prevent the in-place conversion process used for the formation inside the barrier on the formation from the outside of the barrier. Perimeter barriers can prevent fluid from migrating from the treatment area. Perimeter barriers can prevent the temperature from rising to a pyrolysis temperature on the outside of the perimeter barrier.

Some formations have a relatively thin overlap over part of the formation. Some formations may have rock outcrops that approach or extend to the surface of the earth. In some formations, during heat treatment, faults or developing cracks may appear in the overlap that extend to or approach the surface. Some formations may have permeable parts that allow formation fluid to escape into the atmosphere when the formation is heated. For this part of the formation, which will provide or potentially provide the outlet fluid of the formation to the atmosphere during heat treatment, a primer coating may be provided.

In situ formation processing can significantly alter formation characteristics, such as permeability and structural strength. Hydrocarbon production from the formation corresponds to the removal of hydrocarbon-containing material from the formation. In some formations, heat introduced into the formation can cause cracking of the formation. The removal of hydrocarbon-containing material and the formation of cracks can affect the structural integrity of the formation. Selected areas in the treatment area may remain untreated in order to preserve the structural integrity of the formation, prevent subsidence of the rock and / or prevent the propagation of cracks.

Example

Hydrocarbon fluids are obtained from a portion of the carbon formation in which the on-site experiment is conducted. Coal is a highly volatile bituminous coal C. The formation is heated by electric heaters. 12 is a cross-sectional view showing an experimental field test system in place. As can be seen from FIG. 12, the experimental full-scale test system includes a carbon-containing formation 88. The treatment area 76 is located inside the barrier 84 around the perimeter, which is a cemented wall. The hydrocarbon layer 58 has an inclination angle of approximately 36 ° and a thickness of approximately 4.9 m. FIG. 13 shows the locations of heat sources 44a, 44b, 44c, production wells 48a, 48b, and registration wells 90a, 90b, 90c, 90d that are used in the experimental system of full-scale tests. Three heat sources are located in a triangular configuration. Production well 48a is located directly in the center of the heat source layout and at an equal distance from each heat source. The second production well 48b is located outside the layout of the heat sources, at an equal distance from the two nearest heat sources. A perimeter barrier 84 is formed around the contour of the location of heat sources and production wells. The cemented wall is formed of 24 support columns. A perimeter barrier 84 prevents water from entering a portion of the formation during an in situ experiment. In addition, a perimeter barrier 84 prevents loss of the resulting fluid hydrocarbon products into the unheated portion of the formation.

The temperature values are measured at different times of the experiment, in each of the four registration wells 90a, 90b, 90c, 90d, which are located inside and outside the contour of the location of the heat sources, as shown in Fig. 13. On Fig shows the dependence of the temperature measured in each registration well, from time to time. The temperature values in the registration wells 90a (represented by line 92a), 90b (represented by line 92b) and 90c (represented by line 92c) were fairly close to each other. The temperature value in the registration well 90d (92d) was significantly lower. This temperature recording well is located outside the triangular arrangement of heat sources shown in FIG. 13. These data demonstrate that in areas where there is little overlap of heat fluxes, the temperature is significantly lower. 15 shows temperature profiles measured near heat sources 44a (represented by line 94a), 44b (represented by line 94b) and 44c (represented by line 94c). The temperature profiles of the heat sources were relatively uniform.

On Fig shows the dependence of the total volume (in cubic meters) of produced liquid hydrocarbons (96) from time (in days). On Fig shows the dependence of the total volume (in cubic meters) of produced gas (98) from time (in days) in the same experiment in place. Both FIGS. 16 and 17 show the results during the pyrolysis step only in the in situ experiment.

On Fig shows the distribution of the number of carbon atoms in condensing hydrocarbons produced using a slow low-temperature pyrolysis process. During processing, products of relatively high quality are formed. The results in FIG. 18 are consistent with the results presented in FIG. 19, which shows the results obtained by heating coal from the same formation in the laboratory, at heating rates similar to those used in the experiment in situ.

Table 1 summarizes the results of the analysis of coal before treatment and after it was subjected to heat treatment (including pyrolysis by heating and the production of synthesis gas). Coal core is taken from the formation, located approximately 11-11.3 meters below the surface and in the middle of the coal layer, for both pre-treatment and after-treatment samples. Both cores are taken from approximately the same place. Both cores are taken approximately 0.66 m from the heat source 44c (between the perimeter barrier 84 and the heat source 44c) shown in FIG. 13. In the following table 1, the abbreviation AF means Fischer analysis, “ref” means that the sample was tested in its original form, without any additional processing. "Water feast." means water obtained by pyrolysis; “atomic rel. N / C” means the ratio of the number of hydrogen atoms to the number of carbon atoms, “sbz” means dry, ashless, “sbm” means dry, without minerals, and “BMW” means without minerals. The specific gravity of the post-treatment core sample is approximately 0.85, while the specific gravity of the pre-treatment core sample is approximately 1.35.

Table 1 Analysis Before processing After processing The degree of reflection of vitrinite,% 0.54 5.16 AF (gallon * / t, ref) 11.81 0.17 AF (wt.%, Ref) 6.1 0.61 Water feast. AF (gallon * / t, ref) 10.54 2.22 Atomic rel. N / a 0.85 0.06 N (wt.%, Sbz) 5.31 0.44 0 (wt.%, Sbz) 17.08 3.06 N (wt.%, Sbz) 1.43 1.35 Ash (wt.%, Ref) 32.72 56.50 Bound carbon (wt.%, Sbm) 54.45 94.43 Volatile substances (wt.%, Sbm) 45.55 5.57 Calorific value (BTU / lb #, wet, BMW) 12048 14281 * 1 gallon / t = 3.78 l / t # BTU / lb = 2.32 kJ / kg

Even if the cores were taken outside the areas inside the triangle formed by the three heaters, as in FIG. 13, these cores show that the coal remaining in the formation has changed significantly during processing. The results on the degree of vitrinite reflection, shown in Table 1, indicate that the category of coal remaining in the formation significantly increased during processing. Before processing, coal was highly volatile bituminous coal C. However, after processing, coal is practically anthracite. In one embodiment, the resulting coal may have a vitrinite reflectance of greater than about 2.9% and / or a calorific value of greater than about 25,000 kJ / kg.

The results of the Fischer analysis shown in Table 1 demonstrate that most hydrocarbons in coal are removed during processing. The atomic ratio of hydrogen to carbon demonstrates that most of the hydrogen in coal is removed during processing. A significant amount of nitrogen and ash remains in the formation.

Summarizing the results shown in Table 1, we note that a significant amount of hydrocarbons and hydrogen are removed during the processing of coal by pyrolysis and the generation of synthesis gas. A significant amount of unwanted products (ash and nitrogen) remains in the formation, while a significant amount of the desired products (e.g., condensing hydrocarbons and gas) is removed.

With this description in mind, further improvement and alternative embodiments of various aspects of the invention may be apparent to those skilled in the art. Accordingly, this description should be considered only as illustrative, which is given in order to familiarize specialists in this field of technology with the general nature of the invention. It should be understood that the forms of the invention shown and disclosed in this description should be considered as preferred at present. The elements and materials demonstrated and described in this invention may be replaced by others, details and processes may be simplified, and certain features of the invention may be used independently, as it may become apparent to those skilled in the art after familiarizing themselves with the advantages of this invention . Changes may be made to the described elements of the invention without departing from the spirit and scope of the invention, which is described in the following claims. In addition, it should be borne in mind that the features described in the invention as independent, in some embodiments, may be combined.

Claims (13)

1. A method for producing refined coal from a carbon formation, which comprises treating at least a portion of the carbon formation by supplying heat from at least one or more heaters to heat at least a portion of the carbon formation and production fluids from a carbon formation in which treating a carbon formation increases the category of a portion of coal, and increasing the category at least improves the quality of a portion of coal and the production of at least a portion of the treated coal from treated carbon formation. 2. The method according to claim 1, in which the formation is at least partially pyrolyzed. 3. The method according to claim 1, in which at least a portion of the hydrocarbons in the coal is pyrolyzed. 4. The method according to any one of claims 1 to 3, in which the production of coal includes the production of coal in powder form. 5. The method according to any one of claims 1 to 3, in which the production of coal includes the production of coal in the form of a suspension. 6. The method according to any one of claims 1 to 3, which further includes supplying a fluid to a portion of the treated formation in order to remove at least a portion of the coal. 7. The method according to any one of claims 1 to 3, in which the extracted refined coal includes anthracite. 8. The method according to any one of claims 1 to 3, in which the coal before processing does not contain a significant amount of anthracite, and the produced coal contains a significant amount of anthracite. 9. The method according to any one of claims 1 to 3, in which at least a portion of the obtained refined coal has a carbon content higher than about 87 wt.%. 10. The method according to any one of claims 1 to 3, in which at least a portion of the obtained refined coal has a volatile content of less than about 5 wt.%. 11. The method according to any one of claims 1 to 3, in which at least a portion of the obtained refined coal has a calorific value greater than about 25000 kJ / kg. 12. The method according to any one of claims 1 to 3, in which at least a portion of the obtained charcoal has a vitrinite reflectance of greater than about 2.9%. 13. The method according to any one of claims 1 to 3, in which at least a portion of the obtained refined coal is used in the manufacture of steel.

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