A method and device for selecting and evaluating a coal underground gasification area

Abstract

The embodiment of the present application relates to the technical field of underground coal gasification, and discloses a method and equipment for selecting and evaluating middle-deep underground coal gasification, which comprises the following steps: dividing a pre-determined favorable area of the middle-deep underground coal into multiple different levels of favorable zones according to the geological conditions of the coal seam, the coal quality characteristics and the tectonic hydrological conditions; sorting multiple favorable zones of the same level according to the resource conditions and the engineering geological conditions of the coal seam to generate a sorting result; and selecting and evaluating the middle-deep underground coal according to the site selection parameters of the middle-deep underground coal and / or the sorting result in the favorable zones, wherein the site selection parameters include the geological conditions of the coal seam, resource representation parameters, technical recoverable parameters and economic recoverable parameters. The present application has certain guiding significance for the scientific selection of the middle-deep underground coal gasification, and provides detailed geological basis for the subsequent selection and implementation of the underground gasification process.

Description

Technical Field

[0001] This invention relates to the field of underground coal gasification technology, and in particular to a method, apparatus, equipment, medium, and product procedure for selecting and evaluating medium-deep underground coal gasification sites. Background Technology

[0002] Currently, coal seam underground gasification site selection and evaluation technologies almost exclusively focus on shallow coal seams. Compared to shallow coal seams, medium-deep coal seams are buried at greater depths, and have received less attention and research in the past, resulting in a relatively low level of understanding. A deeper understanding must be gradually gained through continuous investigation, research, testing, and analysis, including the spatial distribution of deep coal seams, coal petrography and quality, thermophysical properties, characteristics of the surrounding rock's roof and floor, and related structural and hydrological conditions. Therefore, the site selection and evaluation process for medium-deep coal seams cannot be rushed like that for shallow seams; it must be implemented in a layered and step-by-step manner, similar to oil and gas exploration. In summary, existing technologies lack a systematic and suitable method for the site selection and evaluation of medium-deep coal seams underground gasification. Summary of the Invention

[0003] The purpose of this invention is to provide at least one selection area, evaluation method, and equipment for underground gasification of medium-deep coal seams, and to provide a selection area and evaluation method suitable for underground gasification of medium-deep coal seams.

[0004] To address the aforementioned technical problems, at least one embodiment of this application provides a method for selecting and evaluating areas for underground gasification of medium-deep coal formations, including:

[0005] Based on the coal seam geological conditions, coal quality characteristics, and tectonic and hydrological conditions, the pre-determined favorable areas of the medium-deep coal seams are divided into multiple favorable zones of different levels.

[0006] Based on the resource conditions and engineering geological conditions of the coal seam, multiple favorable zones of the same level are sorted to generate a sorting result;

[0007] Within the favorable zone, the medium-deep coal seams are selected and evaluated based on the site selection parameters and / or the ranking results; wherein, the site selection parameters include: the geological conditions of the coal seam, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0008] In some embodiments, the step of determining the advantageous area includes:

[0009] The favorable areas of the medium-deep coal seam are selected based on the thickness and volatile matter content of the coal seam.

[0010] In some embodiments, the coal seam thickness in the advantageous region is 5-15 meters; the volatile matter content is not less than 20%.

[0011] In some embodiments, the geological conditions of the coal seam include: the thickness, burial depth, and dip angle of the coal seam;

[0012] The coal quality characteristics include: volatile matter, moisture, ash content, and sulfur content;

[0013] The structural hydrological conditions include: fault characteristics, lithology of the top and bottom plates, and thickness of the aquitard.

[0014] In some embodiments, the resource conditions include: the thickness of the coal seam, volatile matter, moisture content, and sulfur content;

[0015] The engineering geological conditions include: the burial depth, dip angle, lithology of the roof and floor, fault characteristics, and thickness of the aquitard layer of the coal seam.

[0016] In some embodiments, ranking multiple favorable zones of the same level according to the resource conditions and engineering geological conditions of the coal seam includes:

[0017] The ranking score of the current favorable zone is determined based on the following scores and weights: thickness of the coal seam in the current favorable zone, volatile matter, moisture content, sulfur content, burial depth, dip angle, roof and floor lithology, fault characteristics, and aquitard thickness.

[0018] The multiple advantageous zones at the same level are sorted according to their respective queuing scores.

[0019] In some embodiments, within the favorable zone, the intermediate-deep coal seams are selected and evaluated based on the site selection parameters and / or the ranking results, including:

[0020] When multiple favorable zones of the same level exist, the medium-deep coal seams are selected and evaluated within the favorable zones according to the site selection parameters and the sorting results; otherwise;

[0021] Within the favorable zone, the medium-deep coal seams are selected and evaluated based on the coal seam geological conditions, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0022] At least one embodiment of this application also provides a selection and evaluation device for underground gasification of medium-deep coal, comprising:

[0023] The favorable area division module is used to divide the pre-determined favorable areas of the medium-deep coal seam into multiple favorable zones of different levels based on the coal seam geological conditions, coal quality characteristics and tectonic and hydrological conditions.

[0024] The sorting result generation module is used to sort multiple favorable zones of the same level according to the resource conditions and engineering geological conditions of the coal seam, so as to generate sorting results;

[0025] The area selection module is used to select and evaluate the medium-deep coal seam within the favorable zone based on the site selection parameters and / or the sorting results; wherein the site selection parameters include: the geological conditions of the coal seam, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0026] At least one embodiment of this application also provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the above-described method for selecting and evaluating underground gasification of medium-deep coal.

[0027] At least one embodiment of this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for selecting and evaluating underground gasification of medium-deep coal seams.

[0028] The embodiments of this application provide a method for site selection and evaluation of underground gasification of medium-deep coal seams, comprising: first, dividing a pre-determined favorable area of ​​medium-deep coal seams into multiple favorable zones of different levels based on the coal seam geological conditions, coal quality characteristics, and tectonic-hydrological conditions; next, ranking the multiple favorable zones of the same level according to the coal seam resource conditions and engineering geological conditions to generate a ranking result; finally, within the favorable zones, selecting and evaluating medium-deep coal seams based on the site selection parameters and / or ranking results; wherein, the site selection parameters include: coal seam geological conditions, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0029] This invention provides a hierarchical, progressive evaluation index system for site selection, namely, "identifying favorable areas—identifying favorable zones—ranking and prioritizing favorable zones—determining favorable targets." This system provides guidance for the scientific site selection of underground gasification sites for medium-deep coal formations and offers detailed geological data for subsequent underground gasification process selection and implementation. Attached Figure Description

[0030] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, and these illustrative descriptions do not constitute a limitation on the embodiments.

[0031] Figure 1 This is a schematic flowchart of a method for selecting and evaluating underground gasification of medium-deep coal, provided in one embodiment of this application.

[0032] Figure 2 This is a schematic diagram of a rapid evaluation index chart for underground gasification zones of medium-deep coal seams, provided in one embodiment of this application.

[0033] Figure 3 This is a flowchart illustrating step 200 provided in one embodiment of this application;

[0034] Figure 4 This is a flowchart illustrating step 300 provided in one embodiment of this application;

[0035] Figure 5 This is a flowchart illustrating the selection and evaluation method for underground gasification of medium-deep coal as provided in the specific embodiments of this application.

[0036] Figure 6 This is a schematic diagram of the hierarchical progressive zone selection evaluation technology system for underground gasification of medium-deep coal provided in the specific implementation of this application;

[0037] Figure 7 This is a schematic diagram of a selection and evaluation device for underground gasification of medium-deep coal, provided in one embodiment of this application;

[0038] Figure 8 This is a schematic diagram of the structure of an electronic device provided in another embodiment of this application. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this application to help readers better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0040] To facilitate understanding of the embodiments of this application, the technical challenges of selecting and evaluating areas for underground gasification of medium-deep coal seams will be introduced first.

[0041] Understandably, geological evaluation and site selection are crucial for the implementation of Underground Coal Gasification (UCG), and are essential for the construction and stable operation of the gasifier. They determine whether the gasifier can safely, sustainably, and stably produce qualified crude coal gas over a long period. Based on field experience and laboratory research findings from shallow UCG trials, several scholars have proposed criteria for selecting favorable UCG sites. In recent years, some scholars have gradually developed evaluation systems and indicators. Bhutto et al. (2013) from Pakistan proposed a relatively lenient geological evaluation standard for UCG site selection, suggesting that UCG should generally be carried out in lignite seams or hard coal seams from later geological periods, with a burial depth of less than 300m and a thickness generally greater than 1m, thus ensuring relatively high economic efficiency for UCG projects. Polish geologists believe that important geological conditions in the site selection study of underground coal gasification projects include coal resource quantity, coal petrographic and quality characteristics, surrounding rock structure and hydrogeological conditions, geochemical characteristics and mineral composition of the coal seam and surrounding rock, roof and floor permeability, and ground subsidence. Key parameters require a coal seam thickness greater than 1.5m, no interbedded rock, and a roof of mudstone with a thickness greater than 20m. Yang et al. (2016) suggested that the total sulfur content of the coal should be less than 1.0%, the coal seam permeability should be between 50 and 150 mD, the distance between the overlying aquifer and the coal seam should be greater than 100m, and the distance from the fault should be greater than 150m.

[0042] In recent years, some scholars have gradually proposed evaluation systems and indicators. Liu Shuqin et al. have conducted research and discussions on the geological site selection of UCG at different times (2013, 2016, 2019), pointing out that the geological site selection of UCG needs to be comprehensively evaluated from multiple aspects such as coal resource conditions, coal rock and coal quality characteristics, surrounding rock structure and hydrogeological conditions and their stability, and the relevant geological parameters such as coal seam thickness, dip angle, water content, gangue content, distance from fault, roof and floor permeability, and gas permeability are limited. Fu Zhenbin (2018) selected 14 factors from coal seam occurrence conditions, coal quality conditions, geological structure and hydrological conditions, and carried out a feasibility evaluation of UCG using the neural network method. Zheng Chao (2019), after systematically analyzing the coal resource conditions, used the analytic hierarchy process to determine the weight of each level of control factors, constructed 4 primary evaluation indicators and 9 secondary evaluation indicators, and believed that the most critical indicator is the coal rock and coal seam characteristics, accounting for more than one-third. Yin Zhenyong et al. (2020) established a multi-level fuzzy mathematical evaluation model, selecting coalification degree, coal thickness, dip angle, coal seam depth, ash content, microscopic coal and rock composition, surrounding rock lithology, structure, and hydrogeology as evaluation indicators, and constructed an evaluation system for underground coal gasification. Zhou He et al. (2021) classified the conditions affecting the effect of underground coal gasification into seven categories and a total of 41 secondary geological parameters based on their influence on the site selection of gasifiers. Through classification, summarization, and hierarchical quantification, they formed a relatively complex evaluation index system for the selection of underground coal gasification sites.

[0043] Example 1:

[0044] The method for selecting and evaluating areas for underground gasification of medium-deep coal seams, as described in this embodiment, can be applied to electronic devices with communication, computing, and data storage capabilities. The specific process can be as follows: Figure 1 As shown, it includes:

[0045] Step 100: Based on the coal seam geological conditions, coal quality characteristics, and tectonic and hydrological conditions, the predetermined favorable areas of the medium-deep coal seams are divided into multiple favorable zones of different levels.

[0046] Step 200: Sort multiple favorable zones of the same level according to the resource conditions and engineering geological conditions of the coal seam to generate a sorting result;

[0047] Step 300: Within the favorable zone, the medium-deep coal seam is selected and evaluated based on the site selection parameters and / or the sorting results; wherein, the site selection parameters include: the geological conditions of the coal seam, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0048] The embodiments of this application provide a method for site selection and evaluation of underground gasification of medium-deep coal seams, comprising: first, dividing a pre-determined favorable area of ​​medium-deep coal seams into multiple favorable zones of different levels based on the coal seam geological conditions, coal quality characteristics, and tectonic-hydrological conditions; next, ranking the multiple favorable zones of the same level according to the coal seam resource conditions and engineering geological conditions to generate a ranking result; finally, within the favorable zones, selecting and evaluating medium-deep coal seams based on the site selection parameters and / or ranking results; wherein, the site selection parameters include: coal seam geological conditions, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0049] This invention provides a hierarchical, progressive site selection evaluation system for medium-deep coal gasification, implementing it step-by-step from "favorable area—favorable zone—queueing and optimization—favorable target." The evaluation methods differ at each level, and the key parameters involved increase progressively. This method not only enables simple, rapid, scientific, and accurate underground gasification of medium-deep coal, but also allows for quantitative comprehensive site selection and queuing. This provides guidance for the scientific site selection of underground coal gasification sites and offers geological evidence for subsequent underground gasification implementation, significantly contributing to the advancement of the underground coal gasification industry.

[0050] For step 100, underground coal gasification is an engineering technology that involves the controlled combustion of coal in coal-bearing strata underground, producing combustible syngas such as methane, hydrogen, and carbon monoxide under the thermal and chemical effects of the coal. Underground coal gasification at different depths corresponds to three different gasification reaction modes: shallow hydrogen-rich mode, medium-deep methane-rich mode, and deep supercritical ultra-hydrogen-rich mode. Based on this, underground coal gasification can be divided into shallow, medium-deep, and deep types. Shallow underground coal gasification involves coal seams buried less than 500m deep, with gasification reaction pressures generally less than 4.0MPa. The gasification reaction is mainly a dry distillation reaction, and the gasification products are characterized by hydrogen richness. Currently, the vast majority of underground coal gasification field tests worldwide belong to this category. Medium-deep underground coal gasification occurs at coal seam depths of 500m to 2200m. The gasification reaction pressure increases with depth, typically ranging from 4.0MPa to 22.1MPa. The gasification reaction is primarily methanation, and the gasification products are characterized by methane-rich gases. Currently, only a few projects worldwide have achieved medium-deep levels, the most typical being the Swan Mountain coal gasification field experiment in Canada, where the coal seam is buried at a depth of 1400m. Besides differences in the composition of the produced gas, medium-deep underground coal gasification differs significantly from shallow underground gasification in many other aspects. For example, medium-deep underground coal gasification primarily uses drilling methods, resulting in longer gasification channels. It often employs CRIP (Controlled Injection Point Retreat) technology. Due to the increased depth and pressure, it achieves stronger sealing, higher calorific value, and higher gasification efficiency. Consequently, it demands more advanced engineering technology, greater difficulty in construction and monitoring, and significantly higher overall costs. Nevertheless, considering the potential of medium-deep coal resources, gasification efficiency, environmental protection, and technological advancements, medium-deep underground coal gasification will be the main direction for future development.

[0051] Understandably, step 100, based on the rapid evaluation (favorable area), allows for a more refined evaluation of a specific region to identify favorable zones within that region. When conducting zone evaluation, ten particularly important geological parameters are selected from dozens of geological parameters affecting underground coal seams. These ten parameters are then categorized into three main types: coal seam geological conditions, coal quality characteristics, and structural-hydrological conditions. A graded and classified evaluation is then conducted based on these three categories of parameters.

[0052] Regarding step 200, there is a possibility that multiple favorable zones have the same level. In this case, it is necessary to sort the multiple favorable zones with the same level in order to select the best one.

[0053] For step 300, based on steps 100 and 200 (where 200 is considered when multiple favorable zones have the same level, otherwise only 100 needs to be considered), as the research deepens and the objectives are defined, the area selection evaluation process enters the site selection evaluation stage. In addition to considering the geological parameters from the zone evaluation, the site selection evaluation standard for medium-deep coal underground gasification needs to incorporate more detailed parameters to establish a site selection evaluation parameter standard, such as process performance parameters, gasification characteristic parameters, technically recoverable indicators, and economically recoverable indicators.

[0054] Example 2:

[0055] In some examples, a method for selecting and evaluating underground gasification sites for medium-deep coal formations also includes:

[0056] The advantageous region is determined; further, the advantageous region can be determined through the following steps:

[0057] Favorable areas for medium-deep coal seams were selected based on seam thickness and volatile matter content. Through detailed analysis, it was determined that, without considering the characteristics of the coal seam roof, the most critical and readily obtainable geological parameters significantly influencing underground coal gasification are seam thickness and volatile matter content. The coal seam should not be too thick or too thin, and the rate of change in thickness should not exceed 15%. Considering that when the coal seam thickness is small, the cooling effect of the roof and floor will lead to poor underground gasification thermal efficiency and a decrease in the calorific value of the gas, this study considers the optimal coal seam thickness for underground coal gasification to be 5-15 m. Volatile matter is a combustible gas produced by the thermal decomposition of organic matter in coal under certain temperature and conditions. It is a mixture of various hydrocarbons, hydrogen, carbon monoxide, and other compounds. The amount of volatile matter is considered a crucial geological parameter for underground coal gasification, with the lower limit of volatile matter content (≥20%) used as the lower limit.

[0058] Furthermore, this invention establishes a rapid evaluation index for underground coal gasification zones. This index multiplies the coal seam thickness (H) and volatile matter (V) values, and the product is used as the rapid evaluation index for underground coal gasification. Since the product of the optimal lower limit of coal seam gasification thickness (5m) and 60% of the high value of ultra-high volatile matter in coal, and the product of the optimal upper limit of coal seam gasification thickness (15m) and 20% of the low value of medium volatile matter in coal, both are 3, 3 is used as the rapid evaluation index for underground coal gasification. Blocks with a product > 3 are preliminarily evaluated as suitable for underground coal gasification; blocks with a product < 3 are preliminarily evaluated as unsuitable for underground coal gasification, and the larger the product, the better the conditions. Figure 2 ).

[0059] In some examples, the coal seam thickness in the favorable area is 5-15 meters; the volatile matter content is not less than 20%.

[0060] The determination of volatile matter involves the following steps: A certain amount of coal sample is taken and dried to remove moisture. The sample is placed in a furnace and heated to 950-1000℃ under strictly controlled conditions. After heating, it is rapidly cooled and weighed, and the mass lost during heating is calculated to determine the volatile matter content.

[0061] In some examples, the geological conditions of the coal seam include: the thickness, depth, and dip angle of the coal seam;

[0062] Coal seam thickness refers to the vertical thickness of the coal seam, that is, the distance from the top of the coal seam to the bottom.

[0063] The formation of coal seams is closely related to factors such as burial environment and geological history. Variations in coal seam thickness are related to sedimentary environment, sediment type, and geological evolution process.

[0064] Coal seam depth refers to the vertical distance between the coal seam and the surface. Based on depth, coal seams can be classified as shallow (usually less than 100 meters), medium (100-500 meters), and deep (over 500 meters). Furthermore, the depth of the coal seam determines the design and mining difficulty of the mine. The greater the depth, the higher the mining costs, technical requirements, and safety risks.

[0065] Dip angle refers to the degree of inclination of a coal seam relative to the horizontal plane, usually expressed as an angle. The dip angle is influenced by geological structures, faults, folds, and other factors. Certain geological activities can cause coal seams to tilt. Coal seams with large dip angles are more difficult to mine, requiring special mining techniques and equipment to ensure safety and efficiency. For example, an excessively large dip angle may lead to coal seam collapse or landslides during mining.

[0066] The coal quality characteristics include: volatile matter, moisture, ash content, and sulfur content;

[0067] Moisture content refers to the percentage of water by mass contained in a coal sample, including apparent moisture and intrinsic moisture. Coal with high moisture content requires more energy to evaporate the moisture during combustion, thus reducing its effective calorific value.

[0068] Ash content refers to the percentage by mass of inorganic minerals remaining after coal combustion. High-ash coal produces more ash during combustion, potentially reducing its calorific value and combustion efficiency. High-ash coal can also cause boiler wear and blockage during combustion, increasing maintenance costs. The composition and content of ash affect the properties of post-combustion emissions, potentially causing varying degrees of environmental pollution.

[0069] Sulfur content refers to the percentage by mass of sulfur in a coal sample. Burning sulfur-containing coal produces sulfur dioxide (SO2), a major contributor to acid rain, which is harmful to the environment and human health. High-sulfur coal requires desulfurization measures during combustion, increasing processing costs.

[0070] The structural hydrological conditions include: fault characteristics, lithology of the top and bottom plates, and thickness of the aquitard.

[0071] Fault characteristics refer to the fracturing and displacement phenomena in coal seams caused by crustal movement, including the type, scale, displacement, strike, and dip angle of the fault.

[0072] Faults can be classified into normal faults, reverse faults, and strike-slip faults. Normal faults are usually associated with crustal extension, while reverse faults are associated with crustal compression, and strike-slip faults involve horizontal displacement. The size and displacement of a fault affect the continuity and mineability of coal seams. Large-scale faults can interrupt coal seams, affecting coal continuity and mining difficulty. The presence of faults can lead to the fracturing, folding, or deformation of coal seams, affecting mine safety and mining technology requirements. Simultaneously, faults can also affect hydrological conditions, leading to changes in water flow and the moisture content of coal seams.

[0073] The lithology of the roof and floor refers to the geological characteristics of the surrounding rocks above and below the coal seam, including the rock type, structure, strength, and physicochemical properties.

[0074] Roof lithology: The roof is the rock above the coal seam, and its lithology, thickness, strength, and stability directly affect the safety of coal mining. A hard roof can provide good support, while a weak roof may lead to collapse accidents.

[0075] Floor lithology: The floor is the rock beneath the coal seam, and its lithology determines the burial depth of the coal seam and mining techniques. The floor lithology also has a significant impact on drainage, ventilation, and mining methods of the coal seam.

[0076] Lithology type: Common surrounding rock lithologies include sandstone, shale, limestone, etc. The physical and chemical properties of different lithologies will affect the mining conditions and environment of coal seams.

[0077] The thickness of the aquitard refers to the thickness of the rock layer between the coal seam and the water layer. This rock layer usually has low permeability and can effectively prevent the flow of water.

[0078] The function of the aquitard is to prevent groundwater from seeping into the coal seam, thereby protecting the coal seam from water immersion, reducing the risk of water damage, and ensuring safety during the mining process.

[0079] Thickness impact: The thicker the aquitard, the stronger its water-blocking ability, reducing the risk of coal seam erosion or flooding. Conversely, a thinner aquitard may allow water to flow into the coal seam, affecting mining and coal quality.

[0080] Geological conditions: The lithology, porosity, and permeability of the impermeable layer are key factors determining its effectiveness. Generally, low-permeability rock layers such as clay and mudstone are more effective as impermeable layers.

[0081] In some examples, the resource conditions include: the thickness of the coal seam, volatile matter, moisture content, and sulfur content;

[0082] In some examples, the engineering geological conditions include: the burial depth, dip angle, lithology of the roof and floor, fault characteristics, and thickness of the aquitard.

[0083] In some cases, for step 100, a multi-factor superposition method can be used to identify favorable zones. With deeper research and improved understanding, based on rapid evaluation, a more refined evaluation of a specific area can be conducted to pinpoint favorable zones within that area. When conducting zone evaluation, ten particularly important geological parameters are selected from dozens of geological parameters affecting underground coal seams for hierarchical and categorized evaluation. First, these ten geological parameters are divided into three main categories: coal seam geological conditions, coal petrographic and geological characteristics, and structural and hydrological conditions. Coal seam geological conditions include three parameters: thickness, depth, and dip angle; coal petrographic and geological characteristics include four industrial analysis parameters: volatile matter, moisture, ash content, and sulfur content; and structural and hydrological conditions mainly include parameters such as fault characteristics, roof and floor lithology, and aquitard thickness.

[0084] Secondly, favorable zones are divided into three levels: I, II, and III, based on different threshold ranges. Level I is the best, followed by Level II, and Level III is the worst. Specific evaluation parameters and classification criteria are shown in Table 1. Then, zone evaluation is conducted according to the barrel principle: regardless of which condition is at a low level, the corresponding level of the entire zone is low.

[0085] Table 1 Evaluation Parameters for Favorable Zones of Coal Underground Gasification

[0086]

[0087] In some examples, see Figure 3 Step 200 includes:

[0088] Step 201: Determine the ranking score of the current favorable zone based on the scores and weights of the thickness of the coal seam, the scores and weights of the volatile matter, the scores and weights of the moisture, the scores and weights of the sulfur content, the scores and weights of the burial depth, the scores and weights of the dip angle, the scores and weights of the roof and floor lithology, the scores and weights of the fault characteristics, and the scores and weights of the aquitard thickness.

[0089] Step 202: Sort the multiple advantageous zones at the same level according to their respective queuing scores.

[0090] In steps 201 and 202, to prioritize several favorable zones of the same level, this application also establishes a zone selection ranking method based on the two-factor method. Specifically, the key geological factors affecting underground coal gasification in medium-deep coal seams are classified into two categories: coal seam resource conditions, including five parameters: thickness, volatile matter, moisture, and sulfur content; and engineering geological conditions, including five parameters: burial depth, dip angle, roof and floor lithology, fault characteristics, and aquitard thickness. Each parameter is assigned a different weight according to its influence on underground coal gasification, with an overall weight of 100 for both categories. Each parameter is also divided into three levels (similar to zone evaluation), and scores are assigned according to actual geological conditions: Level I 1.0–0.8, Level II 0.8–0.5, and Level III 0.5–0 (Table 2). The coal seam resource condition evaluation score R and the engineering geological condition evaluation score P are obtained by multiplying the scores of each parameter of the coal seam resource conditions and engineering geological conditions by their respective weights.

[0091] Coal seam resource conditions R = A * R 厚度 +B*R 挥发 +C*R 水分 +D*R 灰分 +E*R 硫 ;

[0092] Engineering geological conditions P=a*P 埋深 +b*P 倾角 +c*P 岩性 +d*P 隔层 +e*P 断层 ;

[0093] Where: R ——— Coal seam resource condition evaluation score;

[0094] R 煤厚 —Comprehensive evaluation score of coal seam thickness;

[0095] R 挥发 —Comprehensive evaluation score of volatile matter;

[0096] R 水分 —Comprehensive moisture evaluation score;

[0097] R 灰分 —Comprehensive evaluation score of gray content;

[0098] R 硫 —Sulfur content evaluation score;

[0099] A, B, C, and D are the weights of coal seam resource condition parameters, and A+B+C+D+E=100.

[0100] P — Engineering geological condition evaluation score;

[0101] P埋深 —Comprehensive evaluation score of coal seam burial depth;

[0102] P 倾角 —Comprehensive evaluation score of coal seam dip angle;

[0103] P 岩性 —Comprehensive evaluation score of lithology of the top and bottom plates of the coal seam;

[0104] P 隔层 —Comprehensive evaluation score of waterproof layer thickness;

[0105] P 断层 —Comprehensive fault evaluation score;

[0106] The weights of engineering geological condition parameters a, b, c, d, and e are given, and a + b + c + d + e = 100.

[0107] Finally, the zone queuing formula is established: And sort the favorable zones according to the size of the S value.

[0108] Table 2 Evaluation parameters for coal underground gasification area selection based on two-factor analysis.

[0109]

[0110]

[0111] In some examples, see Figure 4 Step 300 includes:

[0112] Step 301: When multiple favorable zones of the same level exist, within the favorable zones, the medium-deep coal seams are selected and evaluated according to the site selection parameters and the sorting results; otherwise;

[0113] Step 302: Within the favorable zone, the medium-deep coal seam is selected and evaluated based on the coal seam geological conditions, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0114] For steps 301 or 302: Based on the zonal evaluation, as the research deepens and the target is determined, the zoning evaluation process enters the site selection evaluation stage. In addition to considering the geological parameters from the zonal evaluation, the site selection evaluation standard for medium-deep coal underground gasification needs to incorporate more detailed parameters to establish a site selection evaluation parameter standard, such as process performance parameters, gasification characteristic parameters, technically recoverable indicators, and economically recoverable indicators. Each parameter has a specific graded evaluation threshold (Table 3). Finally, a comprehensive evaluation analysis is conducted, and only areas falling within Category I targets of the site selection evaluation standard are potentially suitable for medium-deep coal underground gasification.

[0115] Table 3 Evaluation Criteria for Medium-Deep (500-2000m) UCG Site Selection

[0116]

[0117]

[0118]

[0119] The embodiments of this application provide a method for site selection and evaluation of underground gasification of medium-deep coal seams, comprising: first, dividing a pre-determined favorable area of ​​medium-deep coal seams into multiple favorable zones of different levels based on the coal seam geological conditions, coal quality characteristics, and tectonic-hydrological conditions; next, ranking the multiple favorable zones of the same level according to the coal seam resource conditions and engineering geological conditions to generate a ranking result; finally, within the favorable zones, selecting and evaluating medium-deep coal seams based on the site selection parameters and / or ranking results; wherein, the site selection parameters include: coal seam geological conditions, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0120] Medium-deep coal seams are buried at considerable depths, resulting in limited prior research and a relatively low level of understanding. Therefore, the evaluation process for underground gasification sites in medium-deep coal seams cannot be rushed like that for shallow seams; it must be implemented in a tiered and step-by-step manner. This invention provides a hierarchical, progressive evaluation index system for site selection, with different evaluation methods at each level and increasingly important parameters involved. A rapid evaluation method can quickly and easily identify favorable blocks; multi-parameter overlay can conveniently identify favorable zones; a two-factor evaluation can prioritize and optimize favorable zones; and finally, as research deepens and objectives are defined, a comprehensive evaluation can identify favorable targets. This invention not only provides guidance for the scientific site selection of underground gasification sites in medium-deep coal seams but also offers detailed geological data for subsequent underground gasification process selection and implementation.

[0121] Example 3:

[0122] For further explanation of the plan, see Figure 5 The present invention also takes the Jurassic coal seams in the Ordos Basin as an example to provide a specific implementation method for the selection and evaluation of underground gasification of medium-deep coal, which specifically includes the following contents.

[0123] The evaluation process for underground gasification zones in medium-deep coal seams cannot be rushed like that for shallow seas. It must be similar to oil and gas exploration, proceeding in stages and steps: "favorable area—favorable zone—queuing and selection—favorable target." The evaluation methods differ at each level, and the key parameters involved increase progressively. Specific evaluation methods and key parameters are detailed in [link to relevant documentation]. Figure 6 .

[0124] The Jurassic coal seams in the Ordos Basin are mainly distributed in the north, west, and south, with a cumulative thickness of >20m, and the coal rank is lignite to gas coal. In a certain mining area in the north, the average thickness of the Jurassic coal seams is 10m, with a volatile matter content of 33.5%.

[0125] S1: Rapid evaluation method.

[0126] Thickness * volatile matter = 10 * 0.335 = 3.35, indicating a result > 3. Therefore, it is preliminarily believed that this area is suitable for underground coal gasification.

[0127] S2: Multiple parameters superposition.

[0128] Within this block, all parameters related to coal seam conditions, coal petrology and quality, structural conditions, and hydrological conditions fall within the Class I range. Therefore, this block is evaluated as a Class I favorable zone.

[0129] S3: Two-factor evaluation.

[0130] Within this block, various geological parameters of a certain zone were assigned scores, resulting in a coal seam resource condition (R) score of 84 and an engineering geological condition (P) score of 86. Finally, based on the zone ranking formula: The calculated value of S is 85. Compared with other favorable zones, a larger value will rank higher, and a smaller value will rank lower.

[0131] S4: Comprehensive evaluation method.

[0132] As the research deepened and the objectives were defined, the site selection evaluation process entered the stage of site evaluation. The parameters of the selected site were then compared with the deep (500-2000m) UCG site selection evaluation criteria in Table 3. If all parameters met the Class I criteria, the site was determined to be relatively suitable for underground coal gasification; otherwise, it was considered basically suitable or unsuitable.

[0133] This application provides a method for selecting and evaluating underground gasification sites for medium-deep coal seams, comprising: first, dividing a pre-determined favorable area of ​​medium-deep coal seams into multiple favorable zones at different levels based on the coal seam geological conditions, coal quality characteristics, and tectonic-hydrological conditions; next, ranking the multiple favorable zones at the same level according to the coal seam resource conditions and engineering geological conditions to generate a ranking result; finally, within the favorable zones, selecting and evaluating medium-deep coal seams based on the site selection parameters and / or ranking results; wherein the site selection parameters include: coal seam geological conditions, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0134] Medium-deep coal seams are buried at considerable depths, resulting in limited prior research and a relatively low level of understanding. Therefore, the evaluation process for underground gasification sites in medium-deep coal seams cannot be rushed like that for shallow seams; it must be implemented in a tiered and step-by-step manner. This invention provides a hierarchical, progressive evaluation index system for site selection, with different evaluation methods at each level and increasingly important parameters involved. A rapid evaluation method can quickly and easily identify favorable blocks; multi-parameter overlay can conveniently identify favorable zones; a two-factor evaluation can prioritize and optimize favorable zones; and finally, as research deepens and objectives are defined, a comprehensive evaluation can identify favorable targets. This invention not only provides guidance for the scientific site selection of underground gasification sites in medium-deep coal seams but also offers detailed geological data for subsequent underground gasification process selection and implementation.

[0135] Example 4:

[0136] Another embodiment of this application relates to a selection and evaluation device for medium-deep underground coal gasification. The implementation details of this embodiment's selection and evaluation device for medium-deep underground coal gasification are described below. The following details are provided for ease of understanding and are not essential for implementing this solution. A schematic diagram of this embodiment's selection and evaluation device for medium-deep underground coal gasification can be seen as follows: Figure 7 As shown, there is a favorable area division module 801, a sorting result generation module 802, and a selection area module 803.

[0137] The favorable area division module 801 is used to divide the pre-determined favorable area of ​​the medium-deep coal seam into multiple favorable zones of different levels based on the coal seam geological conditions, coal quality characteristics and tectonic hydrological conditions.

[0138] The sorting result generation module 802 is used to sort multiple favorable zones of the same level according to the resource conditions and engineering geological conditions of the coal seam, so as to generate sorting results.

[0139] The area selection module 803 is used to select and evaluate the medium-deep coal seam within the favorable zone based on the site selection parameters of the medium-deep coal seam and / or the sorting results; wherein the site selection parameters include: the geological conditions of the coal seam, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0140] In some embodiments, a selection and evaluation device for medium-deep underground coal gasification further includes:

[0141] A favorable area determination module, used to determine the favorable area; the favorable area determination module includes:

[0142] A favorable area determination unit is used to select favorable areas of the medium-deep coal seam based on the thickness and volatile matter content of the coal seam.

[0143] In some embodiments, the coal seam thickness in the advantageous region is 5-15 meters; the volatile matter content is not less than 20%.

[0144] In some embodiments, the geological conditions of the coal seam include: the thickness, burial depth, and dip angle of the coal seam;

[0145] The coal quality characteristics include: volatile matter, moisture, ash content, and sulfur content;

[0146] The structural hydrological conditions include: fault characteristics, lithology of the top and bottom plates, and thickness of the aquitard.

[0147] In some embodiments, the resource conditions include: the thickness of the coal seam, volatile matter, moisture content, and sulfur content;

[0148] The engineering geological conditions include: the burial depth, dip angle, lithology of the roof and floor, fault characteristics, and thickness of the aquitard layer of the coal seam.

[0149] In some embodiments, the sorting result generation module 802 includes:

[0150] The queuing score determination unit is used to determine the queuing score of the current favorable zone based on the scores and weights of the thickness of the coal seam in the current favorable zone, the scores and weights of the volatile matter, the scores and weights of the moisture, the scores and weights of the sulfur content, the scores and weights of the burial depth, the scores and weights of the dip angle, the scores and weights of the roof and floor lithology, the scores and weights of the fault characteristics, and the scores and weights of the aquitard thickness.

[0151] The sorting result generation unit is used to sort the multiple advantageous zones at the same level according to their respective queuing scores.

[0152] In some embodiments, the selection module 803 includes:

[0153] The first unit of the selection area is used to select and evaluate the medium-deep coal seam within the favorable zone according to the site selection parameters and the sorting results when multiple favorable zones of the same level exist; otherwise;

[0154] The second selection unit is used to select and evaluate the medium-deep coal seams within the favorable zone based on the coal seam geological conditions, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0155] An embodiment of this application provides a site selection and evaluation device for underground gasification of medium-deep coal seams, comprising: a favorable area division module, used to divide a pre-determined favorable area of ​​medium-deep coal seams into multiple favorable zones of different levels based on the coal seam geological conditions, coal quality characteristics, and tectonic hydrological conditions; a ranking result generation module, used to rank multiple favorable zones of the same level based on the coal seam resource conditions and engineering geological conditions to generate ranking results; and a site selection module, used to select and evaluate medium-deep coal seams within the favorable zones based on the site selection parameters and / or ranking results; wherein the site selection parameters include: coal seam geological conditions, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0156] This invention provides a hierarchical, progressive evaluation index system for site selection, namely, "identifying favorable areas—identifying favorable zones—ranking and prioritizing favorable zones—determining favorable targets." This system provides guidance for the scientific site selection of underground gasification sites for medium-deep coal formations and offers detailed geological data for subsequent underground gasification process selection and implementation.

[0157] It is worth mentioning that all modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this application, this embodiment does not introduce units that are not closely related to solving the technical problems proposed in this application; however, this does not mean that other units are absent in this embodiment.

[0158] Example 5:

[0159] Another embodiment of this application relates to an electronic device, such as... Figure 8 As shown, the electronic device specifically includes the following:

[0160] Processor 1201, memory 1202, communications interface 1203, and bus 1204;

[0161] The processor 1201, memory 1202, and communication interface 1203 communicate with each other via bus 1204; the communication interface 1203 is used to realize information transmission between server-side devices and user-side devices and other related devices.

[0162] The processor 1201 is used to call the computer program in the memory 1202. When the processor executes the computer program, it implements all the steps in the selection and evaluation method for underground gasification of medium-deep coal in the above embodiments. For example, when the processor executes the computer program, it implements the following steps:

[0163] Based on the coal seam geological conditions, coal quality characteristics, and tectonic and hydrological conditions, the pre-determined favorable areas of the medium-deep coal seams are divided into multiple favorable zones of different levels.

[0164] Based on the resource conditions and engineering geological conditions of the coal seam, multiple favorable zones of the same level are sorted to generate a sorting result;

[0165] Within the favorable zone, the medium-deep coal seams are selected and evaluated based on the site selection parameters and / or the ranking results; wherein, the site selection parameters include: the geological conditions of the coal seam, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0166] In some embodiments, the step of determining the advantageous area includes:

[0167] The favorable areas of the medium-deep coal seam are selected based on the thickness and volatile matter content of the coal seam.

[0168] In some embodiments, the coal seam thickness in the advantageous region is 5-15 meters; the volatile matter content is not less than 20%.

[0169] In some embodiments, the geological conditions of the coal seam include: the thickness, burial depth, and dip angle of the coal seam;

[0170] The coal quality characteristics include: volatile matter, moisture, ash content, and sulfur content;

[0171] The structural hydrological conditions include: fault characteristics, lithology of the top and bottom plates, and thickness of the aquitard.

[0172] In some embodiments, the resource conditions include: the thickness of the coal seam, volatile matter, moisture content, and sulfur content;

[0173] The engineering geological conditions include: the burial depth, dip angle, lithology of the roof and floor, fault characteristics, and thickness of the aquitard layer of the coal seam.

[0174] In some embodiments, ranking multiple favorable zones of the same level according to the resource conditions and engineering geological conditions of the coal seam includes:

[0175] The ranking score of the current favorable zone is determined based on the following scores and weights: thickness of the coal seam in the current favorable zone, volatile matter, moisture content, sulfur content, burial depth, dip angle, roof and floor lithology, fault characteristics, and aquitard thickness.

[0176] The multiple advantageous zones at the same level are sorted according to their respective queuing scores.

[0177] In some embodiments, within the favorable zone, the intermediate-deep coal seams are selected and evaluated based on the site selection parameters and / or the ranking results, including:

[0178] When multiple favorable zones of the same level exist, the medium-deep coal seams are selected and evaluated within the favorable zones according to the site selection parameters and the sorting results; otherwise;

[0179] Within the favorable zone, the medium-deep coal seams are selected and evaluated based on the coal seam geological conditions, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0180] The memory and processor are connected via a bus, which can include any number of interconnecting buses and bridges, connecting various circuits of one or more processors and memories. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over the wireless medium via an antenna, which further receives data and transmits it to the processor.

[0181] The processor manages the bus and general processing, and also provides various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory is used to store data used by the processor during operation.

[0182] Example 6:

[0183] Another embodiment of this application relates to a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the steps in the above-described embodiments of the selection and evaluation method for underground gasification of medium-deep coal seams, the steps including:

[0184] Based on the coal seam geological conditions, coal quality characteristics, and tectonic and hydrological conditions, the pre-determined favorable areas of the medium-deep coal seams are divided into multiple favorable zones of different levels.

[0185] Based on the resource conditions and engineering geological conditions of the coal seam, multiple favorable zones of the same level are sorted to generate a sorting result;

[0186] Within the favorable zone, the medium-deep coal seams are selected and evaluated based on the site selection parameters and / or the ranking results; wherein, the site selection parameters include: the geological conditions of the coal seam, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0187] In some embodiments, the step of determining the advantageous area includes:

[0188] The favorable areas of the medium-deep coal seam are selected based on the thickness and volatile matter content of the coal seam.

[0189] In some embodiments, the coal seam thickness in the advantageous region is 5-15 meters; the volatile matter content is not less than 20%.

[0190] In some embodiments, the geological conditions of the coal seam include: the thickness, burial depth, and dip angle of the coal seam;

[0191] The coal quality characteristics include: volatile matter, moisture, ash content, and sulfur content;

[0192] The structural hydrological conditions include: fault characteristics, lithology of the top and bottom plates, and thickness of the aquitard.

[0193] In some embodiments, the resource conditions include: the thickness of the coal seam, volatile matter, moisture content, and sulfur content;

[0194] The engineering geological conditions include: the burial depth, dip angle, lithology of the roof and floor, fault characteristics, and thickness of the aquitard layer of the coal seam.

[0195] In some embodiments, ranking multiple favorable zones of the same level according to the resource conditions and engineering geological conditions of the coal seam includes:

[0196] The ranking score of the current favorable zone is determined based on the following scores and weights: thickness of the coal seam in the current favorable zone, volatile matter, moisture content, sulfur content, burial depth, dip angle, roof and floor lithology, fault characteristics, and aquitard thickness.

[0197] The multiple advantageous zones at the same level are sorted according to their respective queuing scores.

[0198] In some embodiments, within the favorable zone, the intermediate-deep coal seams are selected and evaluated based on the site selection parameters and / or the ranking results, including:

[0199] When multiple favorable zones of the same level exist, the medium-deep coal seams are selected and evaluated within the favorable zones according to the site selection parameters and the sorting results; otherwise;

[0200] Within the favorable zone, the medium-deep coal seams are selected and evaluated based on the coal seam geological conditions, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

[0201] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. In particular, hardware + program embodiments are relatively simple in description because they are fundamentally similar to method embodiments; relevant parts can be referred to the descriptions in the method embodiments.

[0202] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0203] While this application provides method operation steps as shown in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-inventive labor. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only execution order. In actual device or client product execution, the method can be executed sequentially as shown in the embodiments or drawings, or in parallel (e.g., in a parallel processor or multi-threaded processing environment).

[0204] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0205] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0206] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0207] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for selecting and evaluating underground gasification sites for medium-deep coal seams, characterized in that, include: Based on the coal seam geological conditions, coal quality characteristics, and tectonic and hydrological conditions, the pre-determined favorable areas of the medium-deep coal seams are divided into multiple favorable zones of different levels. Based on the resource conditions and engineering geological conditions of the coal seam, multiple favorable zones of the same level are sorted to generate a sorting result; Within the favorable zone, the medium-deep coal seams are selected and evaluated based on the site selection parameters and / or the sorting results; wherein, the site selection parameters include: the geological conditions of the coal seam, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

2. The selection and evaluation method according to claim 1, characterized in that, The steps for determining the advantageous area include: The favorable areas of the medium-deep coal seam are selected based on the thickness and volatile matter content of the coal seam.

3. The selection and evaluation method according to claim 2, characterized in that, The coal seam thickness in the favorable area is 5-15 meters; the volatile matter content is not less than 20%.

4. The selection and evaluation method according to claim 1, characterized in that, The geological conditions of the coal seam include: the thickness, burial depth, and dip angle of the coal seam; The coal quality characteristics include: volatile matter, moisture, ash content, and sulfur content; The structural hydrological conditions include: fault characteristics, lithology of the top and bottom plates, and thickness of the aquitard.

5. The selection and evaluation method according to claim 1, characterized in that, The resource conditions include: the thickness of the coal seam, volatile matter, moisture content, and sulfur content; The engineering geological conditions include: the burial depth, dip angle, lithology of the roof and floor, fault characteristics, and thickness of the aquitard layer of the coal seam.

6. The selection and evaluation method according to claim 5, characterized in that, Based on the resource conditions and engineering geological conditions of the coal seam, multiple favorable zones of the same level are ranked, including: The ranking score of the current favorable zone is determined based on the following scores and weights: thickness of the coal seam in the current favorable zone, volatile matter, moisture content, sulfur content, burial depth, dip angle, roof and floor lithology, fault characteristics, and aquitard thickness. The multiple advantageous zones at the same level are sorted according to their respective queuing scores.

7. The selection area and evaluation method according to any one of claims 1 to 6, characterized in that, Within the favorable zone, the medium-deep coal seams are selected and evaluated based on the site selection parameters and / or the ranking results, including: When multiple favorable zones of the same level exist, the medium-deep coal seams are selected and evaluated within the favorable zones according to the site selection parameters and the sorting results; otherwise; Within the favorable zone, the medium-deep coal seams are selected and evaluated based on the coal seam geological conditions, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

8. A selection and evaluation device for underground gasification of medium-deep coal, characterized in that, include: The favorable area division module is used to divide the pre-determined favorable areas of the medium-deep coal seam into multiple favorable zones of different levels based on the coal seam geological conditions, coal quality characteristics and tectonic and hydrological conditions. The sorting result generation module is used to sort multiple favorable zones of the same level according to the resource conditions and engineering geological conditions of the coal seam, so as to generate sorting results; The area selection module is used to select and evaluate the medium-deep coal seam within the favorable zone based on the site selection parameters and / or the sorting results; wherein the site selection parameters include: the geological conditions of the coal seam, resource characterization parameters, technically recoverable parameters, and economically recoverable parameters.

9. An electronic device, characterized in that, include: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the selection and evaluation method for underground gasification of medium-deep coal as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the selection and evaluation methods for underground gasification of medium-deep coal as described in any one of claims 1 to 7.

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