Coal underground gasification site selection system and method for multi-parameter collaborative evaluation

Abstract

The invention relates to the technical field of coal underground gasification site selection, and discloses a coal underground gasification site selection system and method based on multi-parameter collaborative evaluation.The coal underground gasification site selection method comprises the following steps that coal resource data of a target area are collected and examined, and influence factors are screened and analyzed; comparing the collected coal resource data with corresponding influence factor evaluation standards, and respectively obtaining each factor estimated value of the corresponding influence factor; calculating the suitability coefficient of each factor of the influence factors and the average suitability coefficient of the influence factors according to the estimation condition of each factor of the target area influence factors; according to the method, a complete multi-dimensional evaluation index system is constructed, the coal bed gasification suitability is comprehensively evaluated from multiple dimensions, and the one-sidedness of evaluation is avoided; meanwhile, a scientific quantitative evaluation mechanism is established, qualitative factors are converted into quantitative indexes through grade quantification, and the objectivity and scientificity of evaluation are improved by combining dimensionless processing and weight distribution.

Description

Technical Field

[0001] The present invention relates to the technical field of underground coal gasification site selection, and more particularly, to an underground coal gasification site selection system and method for multi-parameter collaborative evaluation. Background Art

[0002] Underground coal gasification (UCG), a clean and efficient method of coal utilization, effectively addresses the safety risks and environmental pollution associated with traditional coal mining. This technology converts coal seams into combustible gas in situ, eliminating the need to bring coal to the surface. This eliminates the safety risks associated with underground miners and reduces environmental issues such as surface subsidence and solid waste generation. However, the successful implementation of UCG projects is highly dependent on the selection of suitable coal seams. Improper site selection can lead to a range of issues, including low gasification efficiency, increased environmental risks, and reduced economic benefits.

[0003] The existing underground coal gasification site selection methods have the following main technical problems: 1) The evaluation indicators are single and mostly focus on the coal seam occurrence conditions and coal quality characteristics, ignoring key factors such as hydrogeology and engineering geology, resulting in one-sided evaluation results; 2) The evaluation methods are too simple or highly subjective, mostly using qualitative descriptions or empirical judgments, and lack a systematic quantitative evaluation system; 3) The weight differences between different evaluation indicators are not considered, and all influencing factors are treated equally, which cannot reflect the different degrees of influence of different factors on the gasification process; 4) It is difficult to evaluate and rank multiple potential gasification areas simultaneously, which lacks comparability.

[0004] The above problems have led to existing underground coal gasification projects often encountering unsuitable coal seam conditions, complex geological conditions, and cost overruns during implementation, seriously restricting the promotion and application of this clean coal technology. Summary of the Invention

[0005] The present invention provides a multi-parameter collaborative evaluation underground coal gasification site selection system and method to solve the technical problems in the above-mentioned technologies.

[0006] A first aspect of the present invention provides a multi-parameter collaborative evaluation method for underground coal gasification site selection, comprising the following steps:

[0007] Collect and review coal resource data in the target area, and screen and analyze influencing factors;

[0008] Compare the collected coal resource data with the corresponding influencing factor evaluation standards to obtain the estimated values ​​of each factor of the corresponding influencing factors;

[0009] According to the valuation of each factor of the influencing factors in the target area, the suitability coefficient of each factor and the average suitability coefficient of the influencing factors are calculated;

[0010] Based on the average suitability coefficient of each influencing factor in the target area and the weight of each influencing factor, calculate the weighted suitability coefficient of each factor;

[0011] Calculate the comprehensive suitability coefficient of the target area based on the weighted suitability coefficients of each factor;

[0012] The comprehensive suitability coefficient and suitability grade classification standard are compared to evaluate the suitability of underground coal gasification in the coal seams in the target area.

[0013] As a further optimization scheme of the present invention, the coal resource data include: coal seam occurrence conditions, geological structure conditions, hydrogeological conditions, engineering geological conditions, coal quality conditions, coal gasification performance, industrial economic efficiency and environmental geological conditions.

[0014] As a further optimization scheme of the present invention, the calculation formula of the factor suitability coefficient is:

[0015]

[0016] Among them, E represents the factor suitability coefficient, which is a dimensionless index to measure the suitability of each evaluation factor. Its value range is [0,1]. The closer the value is to 1, the more suitable the factor is for underground coal gasification. F v F is the valuation of each factor of the influencing factors; max The maximum value assigned to the suitability;

[0017] The calculation formula for the average suitability coefficient is:

[0018]

[0019] Among them, E p is the average suitability coefficient of each influencing factor; n is the total number of factors under a certain influencing factor; E i is the suitability coefficient of the i-th factor; It represents the sum of the fitness coefficients of all factors.

[0020] As a further optimization solution of the present invention, the weighted suitability coefficient calculation formula is:

[0021] E pw =E p ×W;

[0022] Among them, E pw is the weighted suitability coefficient of each factor, E p is the average suitability coefficient of each influencing factor; W is the weight of each influencing factor, indicating the importance of the factor in the evaluation system;

[0023] The calculation formula for the comprehensive suitability coefficient is:

[0024]

[0025] Among them, E z The comprehensive suitability coefficient indicates the overall suitability of the coal seams in the target area for underground coal gasification. It is the final quantitative indicator of the evaluation results and has a value range of [0,1]. The closer the value is to 1, the more suitable the area is for underground coal gasification projects. represents the weighted suitability coefficient of the jth influencing factor; represents the sum of all weighted fitness coefficients.

[0026] As a further optimization solution of the present invention, the suitability grade classification standard is:

[0027] Comprehensive suitability coefficient ≥0.9 is very suitable;

[0028] 0.8≤comprehensive suitability coefficient<0.9 is relatively suitable;

[0029] 0.6≤comprehensive suitability coefficient<0.8 is generally suitable;

[0030] 0.4≤comprehensive suitability coefficient<0.6 is relatively unsuitable;

[0031] A comprehensive suitability coefficient <0.4 is unsuitable.

[0032] As a further optimization scheme of the present invention, the comprehensive suitability coefficient is calculated using the TOPSIS method, comprising the following steps:

[0033] Constructing a standardized decision matrix;

[0034] Determine indicator weights and weighted standardized decision matrix;

[0035] Determine ideal solutions and negative ideal solutions;

[0036] Calculate the distance from each evaluation object to the ideal solution and the negative ideal solution;

[0037] Calculate the comprehensive suitability coefficient of each evaluation object.

[0038] As a further optimization solution of the present invention, the normalization processing formula in the normalization decision matrix is ​​constructed as follows:

[0039]

[0040] R=(r ua ) p×q ;

[0041] Among them, r ua represents the standardized value of the ath indicator of the uth evaluation object in the standardized matrix; X ua Represents the original value of the ath indicator of the yth evaluation object in the original data matrix; represents the sum of the squares of the original values ​​of all evaluation objects u under the same indicator a from u = 1 to p; R represents the normalized matrix;

[0042] The weighted normalization matrix is:

[0043] v ua =w a ×r ua ;

[0044] V=(v ua ) p×q ;

[0045] Among them, v ua represents the weighted normalized value of the ath indicator of the uth evaluation object in the weighted normalized matrix; w a Indicates the weight value of the ath evaluation index; r ua represents the standardized value of the ath indicator of the uth evaluation object in the standardized matrix; V represents the weighted standardized decision matrix; V represents the weighted standardized decision matrix; p represents the number of evaluation objects, that is, the number of underground coal gasification areas to be evaluated; q represents the number of evaluation indicators, that is, the total number of various parameter indicators used for evaluation.

[0046] As a further optimization solution of the present invention, the weights of the various influencing factors are adjusted according to the characteristics of coal resources in different regions.

[0047] A second aspect of the present invention provides a multi-parameter collaborative evaluation underground coal gasification site selection system, which is used to execute the multi-parameter collaborative evaluation underground coal gasification site selection method according to claims 1 to 9, and is characterized by comprising:

[0048] Data acquisition module, used to collect and review data on the occurrence conditions, geological structure conditions, hydrogeological conditions, engineering geological conditions, coal quality conditions, coal gasification performance, industrial economic factors and environmental geological conditions of the coal seams in the project area;

[0049] The data processing module is used to compare the collected data with the preset evaluation criteria, obtain the valuation of each factor of the corresponding influencing factors, and calculate the suitability coefficient of each factor of the influencing factors and the average suitability coefficient of the influencing factors;

[0050] Evaluation calculation module, used to calculate the weighted suitability coefficient of each factor and the comprehensive suitability coefficient or relative proximity of the project area according to the weight of each influencing factor;

[0051] The result judgment module is used to evaluate the suitability level of underground coal gasification in the coal seams in the project area based on the comprehensive suitability coefficient or relative proximity, and classify the evaluation results into grades;

[0052] The user interface module is used to display the evaluation results and provide data input, parameter adjustment and result export functions.

[0053] The beneficial effects of the present invention are:

[0054] The multi-parameter collaborative evaluation method for underground coal gasification site selection provided by the present invention mainly has the following beneficial effects: the present invention constructs a complete multi-dimensional evaluation index system, comprehensively evaluates the suitability of coalbed gasification from multiple dimensions, and avoids the one-sidedness of the evaluation; at the same time, a scientific quantitative evaluation mechanism is established, and qualitative factors are converted into quantitative indicators through hierarchical quantification. Combined with dimensionless processing and weight distribution, the collaborative evaluation of different factors is realized, and the objectivity and scientificity of the evaluation are improved; and the method is simple and easy to implement, and has strong applicability, providing systematic and standardized technical support for the scientific site selection of underground coal gasification projects, which is conducive to improving the success rate of projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a flow chart of a multi-parameter collaborative evaluation method for underground coal gasification site selection according to Example 1 of the present invention;

[0056] Figure 2 This is a flow chart of a multi-parameter collaborative evaluation method for underground coal gasification site selection according to Example 2 of the present invention. DETAILED DESCRIPTION

[0057] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that these embodiments are discussed solely to enable those skilled in the art to better understand and implement the subject matter described herein, and that the functions and arrangements of the elements discussed may be varied without departing from the scope of this specification. Various examples may omit, substitute, or add various processes or components as needed. Furthermore, features described in some examples may be combined in other examples.

[0058] At least one embodiment of the present invention discloses a method for underground coal gasification site selection based on multi-parameter collaborative evaluation, such as Figure 1 As shown, the following steps are included:

[0059] Example 1

[0060] This embodiment provides a multi-parameter collaborative evaluation method for underground coal gasification site selection. The method includes the following steps:

[0061] Step 101: Collect and review coal resource data in the target area, and screen and analyze influencing factors;

[0062] Coal resource data include: coal seam occurrence conditions, geological structure conditions, hydrogeological conditions, engineering geological conditions, coal quality conditions, coal gasification performance, industrial economics and environmental geological conditions.

[0063] Specifically, the evaluators obtained original data on coal resources through on-site surveys, drilling sampling, laboratory analysis and other methods.

[0064] Step 102: Compare the collected coal resource data with the corresponding influencing factor evaluation standards to obtain the estimated values ​​of the corresponding influencing factors;

[0065] The evaluation criteria of influencing factors (F) are divided into five levels: very suitable (F=5), relatively suitable (F=4), generally suitable (F=3), relatively unsuitable (F=2) and unsuitable (F=1).

[0066] Specifically, referring to the standards in the evaluation table of each influencing factor, the various parameters of the target area are compared with the evaluation standards to determine its level (very suitable, relatively suitable, generally suitable, relatively unsuitable or unsuitable), and then the corresponding factor estimation F is obtained. v .

[0067] Step 103: Calculate the suitability coefficient (E) of each factor and the average suitability coefficient (E) of each factor according to the estimated value of each factor in the target area. p );

[0068] The calculation formula of factor suitability coefficient is:

[0069]

[0070] Among them, E represents the factor suitability coefficient, which is a dimensionless index to measure the suitability of each evaluation factor. Its value range is [0,1]. The closer the value is to 1, the more suitable the factor is for underground coal gasification. F v F is the valuation of each factor of the influencing factors; max The maximum value assigned to suitability is 5 in this method.

[0071] The calculation formula for the average suitability coefficient is:

[0072]

[0073] Among them, E p is the average suitability coefficient of each influencing factor; n is the total number of factors under a certain influencing factor; E i is the suitability coefficient of the i-th factor; It means summing the fitness coefficients of all factors, that is:

[0074]

[0075] Among them, E1, E2, E n They represent the suitability coefficients of the 1st, 2nd, and nth factors respectively, and n is the total number of factors under a certain influencing factor.

[0076] The suitability coefficient E is a dimensionless processing method that converts the evaluation index values ​​of different dimensions and ranges into the interval [0,1] to facilitate comprehensive comparison and evaluation.

[0077] Step 104: Based on the average suitability coefficient of each influencing factor in the target area and the weight of each influencing factor, calculate the weighted suitability coefficient of each factor;

[0078] The calculation formula of weighted suitability coefficient is:

[0079] E pw =E p ×W

[0080] Among them, E pw is the weighted suitability coefficient of each factor, E p is the average suitability coefficient of each influencing factor; W is the weight of each influencing factor, indicating the importance of the factor in the evaluation system.

[0081] Step 105: Calculate the comprehensive suitability coefficient of the target area based on the weighted suitability coefficients of each factor.

[0082] According to the weighted suitability coefficient of each factor (E pw ), calculate the comprehensive suitability coefficient of the target area (E z );

[0083] The calculation formula for the comprehensive suitability coefficient is:

[0084]

[0085] Among them, E z The comprehensive suitability coefficient indicates the overall suitability of the coal seams in the target area for underground coal gasification. It is the final quantitative indicator of the evaluation results and has a value range of [0,1]. The closer the value is to 1, the more suitable the area is for underground coal gasification projects. represents the weighted suitability coefficient of the jth influencing factor; It represents the sum of all weighted fitness coefficients, that is:

[0086]

[0087] in, They represent the weighted suitability coefficients of the 1st, 2nd, and mth influencing factors, respectively, where m represents the total number of influencing factors.

[0088] Specific implementation method: The weight of each influencing factor is determined by expert evaluation. In this example, the weight of the factors influencing coal seam occurrence conditions, geological structure conditions, hydrogeological conditions, engineering geological conditions, coal quality conditions, and coal gasification performance is 0.14, and the weight of the factors influencing industrial economics and environmental geological conditions is 0.08. For each influencing factor, the average suitability coefficient is multiplied by the corresponding weight to obtain the weighted suitability coefficient.

[0089] Step 106: Compare the comprehensive suitability coefficient and the suitability grade classification standard to evaluate the suitability of the target area coal seam for underground coal gasification;

[0090] The suitability classification standards are as follows:

[0091] E z >0.9: very suitable;

[0092] 0.8≤E z <0.9: quite suitable;

[0093] 0.6≤E z <0.8: generally suitable;

[0094] 0.4≤E z <0.6: less suitable;

[0095] E z <0.4: Unsuitable.

[0096] Specific implementation method: The comprehensive suitability coefficient E calculated in step 3 is z Compare with the suitability classification criteria. For example, if E z =0.8178, then the suitability judgment standard is checked and it is known that the value is between 0.8≤E z Within the range of <0.9, it is judged as "relatively suitable" for UCG projects. This unified standard allows for objective evaluation of the suitability of different target areas for UCG development, providing a scientific basis for project decision-making.

[0097] Application example of embodiment 1

[0098] The following is an example of site selection and evaluation for underground coal gasification in Mine Field A:

[0099] (1) Collect and review the data on the occurrence conditions of the coal seams in the mine field:

[0100] Coal seam thickness in the evaluation area: 5.6-13.3m, average 10.1m;

[0101] Coal seam burial depth in the evaluation area: 380-550m, average 465m;

[0102] Coal seam interbedded with gangue in the evaluation area: contains 0-4 layers of interbedded gangue, with the thickest single layer being 0.67m.

[0103] According to the "Evaluation Table of Factors Affecting Coal Seam Occurrence Conditions" (as shown in Table 1), the estimated scores of each factor of this influencing factor are evaluated and the suitability coefficient of each influencing factor is calculated:

[0104] Factor estimation F of coal seam thickness in the evaluation area v =5; factor suitability coefficient E = 1;

[0105] Factor estimation F of coal seam depth in the evaluation area v =4, factor suitability coefficient E = 0.8;

[0106] Factor estimation F of coal seam intercalation in the evaluation area v =3, factor suitability coefficient Fv=0.6;

[0107] Average suitability coefficient of factors affecting coal seam occurrence conditions:

[0108] E p =(1+0.8+0.6) / 3=0.8.

[0109] Table 1: Evaluation table of factors affecting the occurrence conditions of coal seams for underground coal gasification in A mine field

[0110]

[0111] (2) Collect and review the geological and structural conditions of the coal seams in the target area of ​​the well field:

[0112] Coal seam dip in the evaluation area: 1°-13°, average 5°;

[0113] Fault development in the evaluation area: None;

[0114] Folds in the evaluation area: one broad and gentle dorsal fold and one syncline fold;

[0115] Structural fissures in the assessment area: The fissures are relatively developed but closed;

[0116] Collapse column (or igneous rock) in the evaluation area: None.

[0117] According to the "Evaluation Table of Factors Affecting Geological Structural Conditions" (as shown in Table 2), evaluate the estimated scores of each factor of this influencing factor and calculate the suitability coefficient of each influencing factor:

[0118] Factor estimation F of coal seam inclination in the evaluation area v =5, factor suitability coefficient E=1;

[0119] Factor estimation F of faults in the evaluation area v =5, factor suitability coefficient E=1;

[0120] Factor estimation F of folds in the evaluation areav =4, factor suitability coefficient E = 0.8;

[0121] Factor estimation F of structural fractures in the assessment area v =4, factor suitability coefficient E = 0.8;

[0122] Factor estimation F of the collapse column in the evaluation area v =5, factor suitability coefficient E=1;

[0123] Average suitability coefficient of factors affecting geological structure conditions:

[0124] E p =(1+1+0.8+0.8+1) / 5=0.92.

[0125] Table 2: Evaluation of factors affecting geological structural conditions of underground coal gasification in Mine A

[0126]

[0127] (3) Collect and review the hydrogeological structural conditions of the coal seams in the target area of ​​the well field:

[0128] Evaluation area q index: 0.03536L / sm;

[0129] Hydrostatic pressure in the evaluation area: 4.5 MPa;

[0130] Permeability of the evaluation area: 12.13mD;

[0131] Channel occurrence in the evaluation area: There are a small number of wells and tunnels, and the fracture zones in some areas are highly affected by the Neogene faults.

[0132] According to the "Hydrogeological Condition Factor Evaluation Table" (as shown in Table 3), evaluate the valuation scores of each factor of this influencing factor and calculate the suitability coefficient of each influencing factor:

[0133] Factor estimation F of the q index in the evaluation area v =5, factor suitability coefficient E=1;

[0134] Factor estimation F of hydrostatic pressure in the assessment area v =5, factor suitability coefficient E=1;

[0135] Factor estimation F of permeability in the evaluation area v =3, factor suitability coefficient E = 0.6;

[0136] Factor estimation F of the evaluation area channel v =3, factor suitability coefficient E = 0.6;

[0137] Average suitability coefficient of factors affecting hydrogeological conditions:

[0138] Ep =(1+1+0.6+0.6) / 4=0.8.

[0139] Table 3: Evaluation of factors affecting hydrogeological conditions of underground coal gasification in A field

[0140]

[0141] (4) Collect and review the engineering geological conditions of the target area of ​​the well field:

[0142] Rock quality in the evaluation area: between 50% and 60%;

[0143] Compressive strength of surrounding rock in the evaluation area: 7.6Mpa-32.8Mpa, average 16.6Mpa;

[0144] The tensile strength of the surrounding rock in the evaluation area is 0.52Mpa-2.84Mpa, with an average of 0.9Mpa;

[0145] Cohesion in the evaluation area: 0.6Mpa-3.4Mpa, average 1.55Mpa;

[0146] Friction angle in the evaluation area: 32.4°-42°, average 38.95°;

[0147] Impact ground pressure in the assessment area: None.

[0148] According to the "Evaluation Table of Factors Affecting Engineering Geological Conditions" (as shown in Table 4), evaluate the estimated scores of each factor of this influencing factor and calculate the suitability coefficient of each influencing factor:

[0149] Factor estimation F of rock quality in the evaluation area v =3, factor suitability coefficient E = 0.6;

[0150] Factor estimation of compressive strength of surrounding rock in the evaluation area F v =3, factor suitability coefficient E = 0.6;

[0151] Factor estimation of tensile strength of surrounding rock in the evaluation area F v =3, factor suitability coefficient E = 0.6;

[0152] Factor estimation F of cohesion in the evaluation area v =4, factor suitability coefficient E = 0.8;

[0153] Factor estimation of friction angle in the evaluation area F v =2, factor suitability coefficient E = 0.4;

[0154] Factor estimation F of rock burst in the assessment area v =5, factor suitability coefficient E=1;

[0155] Average suitability coefficient of factors affecting engineering geological conditions:

[0156] E p =(0.6+0.6+0.6+0.8+0.4+1) / 6=0.63.

[0157] Table 4: Evaluation of factors affecting geological conditions of underground coal gasification engineering at A mine field

[0158]

[0159] (5) Collect and review coal quality test data in the target area of ​​the well field:

[0160] Total moisture content in the evaluation area: 11.75%;

[0161] Fault development in the evaluation area: 12.24%;

[0162] Volatile matter in the evaluation area: 34.56%;

[0163] Evaluation area calorific value: 25.76dMJ / kg;

[0164] Total sulfur in the evaluation area: 0.73d%;

[0165] Chlorine in the evaluation area: 0.059%;

[0166] According to the "Evaluation Table of Factors Affecting Coal Quality Conditions" (as shown in Table 5), evaluate the estimated scores of each factor of this influencing factor and calculate the suitability coefficient of each influencing factor:

[0167] Factor estimation F of total moisture in the evaluation area v =4, factor suitability coefficient E = 0.8;

[0168] Factor estimation F of fault development in the evaluation area v =4, factor suitability coefficient E = 0.8;

[0169] Factor estimation F of volatile matter in the assessment area v =4, factor suitability coefficient E = 0.8;

[0170] Factor estimation F of the heat output of the evaluation area v =4, factor suitability coefficient E = 0.8;

[0171] Factor estimation of total sulfur in the assessment area F v =4, factor suitability coefficient E = 0.8;

[0172] Factor estimation F of chlorine in the evaluation area v =4, factor suitability coefficient E = 0.8;

[0173] Average suitability coefficient of factors affecting coal quality conditions:

[0174] E p =(0.8+0.8+0.8+0.8+0.8) / 5=0.8.

[0175] Table 5: Evaluation of factors affecting coal quality conditions for underground coal gasification in A field

[0176]

[0177] (6) Collect and review experimental data on the gasification performance of coal in the target area of ​​the well field:

[0178] Coal type in the evaluation area: CY;

[0179] Permeability of coal in the evaluation area: 13.56mD;

[0180] Evaluation area adhesion index: 0%;

[0181] Expansion coefficient of evaluation area: 1;

[0182] Activity of coal in the evaluation area: 96.5%.

[0183] According to the "Evaluation Table of Factors Affecting Coal Gasification Performance" (as shown in Table 6), the estimated scores of each factor of this influencing factor are evaluated and the appropriate coefficient of each influencing factor is calculated:

[0184] Factor estimation F of coal types in the evaluation area v =4, factor suitability coefficient E = 0.8;

[0185] Factor estimation F of coal permeability in the evaluation area v =3, factor suitability coefficient E = 0.6;

[0186] Factor estimation F of the bonding index of the evaluation area v =5, factor suitability coefficient E=1;

[0187] Factor estimation of expansion coefficient of evaluation area F v =5, factor suitability coefficient E=1;

[0188] Factor estimation F of the activity of coal in the evaluation area v =5, factor suitability coefficient E=1;

[0189] Average suitability coefficient of factors affecting coal gasification performance:

[0190] E p =(0.8+0.6+1+1+1) / 5=0.88.

[0191] Table 6: Evaluation table of factors affecting the gasification performance of underground coal gasification in A field

[0192]

[0193] (7) Collect and review the industrial economic indicators of the coal seams in the target area of ​​the well field:

[0194] Coal seam resources in the evaluation area: 560 million tons;

[0195] Coal seam stability in the evaluation area: relatively stable in most areas;

[0196] Coal seam continuity in the evaluation area: 1100m.

[0197] According to the "Evaluation Table of Factors Affecting the Industrial Economy of Coal" (as shown in Table 7), the valuation scores of each factor of this influencing factor are evaluated and the suitability coefficient of each influencing factor is calculated:

[0198] Factor estimation F of coal seam resources in the evaluation area v =5, factor suitability coefficient E=1;

[0199] Factor estimation F of coal seam stability in the evaluation area v =4, factor suitability coefficient E = 0.8;

[0200] Factor estimation F of coal seam continuity in the evaluation area v =4, factor suitability coefficient E = 0.8;

[0201] Average suitability coefficient of factors affecting industrial economic efficiency:

[0202] E p =(1+0.8+0.8) / 3=0.87.

[0203] Table 7: Evaluation of factors affecting the economic performance of underground coal gasification industry in A field

[0204]

[0205] (8) Collect and review the environmental geological conditions of the target area of ​​the well field:

[0206] Evaluation area depth ratio: 47;

[0207] Endowment of accessories in the assessment area: There is an industrial square (including shafts and a small number of tunnels) within the mining area.

[0208] According to the "Evaluation Table of Environmental Geological Conditions Influencing Factors" (as shown in Table 8), evaluate the estimated scores of each factor of this influencing factor and calculate the suitability coefficient of each influencing factor:

[0209] Factor estimation F of depth ratio of evaluation area v =5, factor suitability coefficient E=1;

[0210] Factor estimation F of the appendage occurrence in the assessment area v =4, factor suitability coefficient E = 0.8;

[0211] Average suitability coefficient of environmental geological conditions:

[0212] E p =(1+0.8) / 2=0.9.

[0213] Table 8: Evaluation of factors affecting the geological conditions of underground coal gasification environment in A field

[0214]

[0215] (9) Based on the average suitability coefficient of each influencing factor in the target area and the weight of each influencing factor, the weighted suitability coefficient of each factor is calculated, as shown in Table 9;

[0216] Table 9: Calculation table of weighted suitability coefficients of various factors for underground coal gasification in A field

[0217]

[0218] (10) Calculate the comprehensive suitability coefficient of the target area:

[0219] E z =0.112+0.1288+0.112+0.0882+0.112+0.1232+0.0696+0.072=0.8178

[0220] (5) The suitability of the target area coal seams for underground coal gasification is determined by combining the comprehensive suitability coefficient and suitability grade classification standards:

[0221] Comprehensive suitability coefficient E of well field at location A z =0.8178, within 0.8≤E z If the value is within the range of <0.9, the final result is determined to be “relatively suitable” for implementing the underground coal gasification project.

[0222] Example 2

[0223] This embodiment provides a method for evaluating underground coal gasification site selection based on the TOPSIS method (Technique for Order Preference by Similarity to an Ideal Solution). Figure 2 As shown, the following steps are included:

[0224] Step 201: Determine the evaluation index system and data collection;

[0225] Similar to Example 1, data is collected from eight dimensions: coal seam occurrence conditions, geological structural conditions, hydrogeological conditions, engineering geological conditions, coal quality, coal gasification performance, industrial economic factors, and environmental geological conditions.

[0226] Implementation: Obtain actual data on various indicators in the area to be evaluated through geological exploration, experimental testing, and data collection. For multiple evaluation targets, it is necessary to ensure that data collection standards are consistent to ensure fairness and accuracy in subsequent comparisons.

[0227] Step 202: construct a standardized decision matrix;

[0228] Specifically, there are p evaluation objects and q evaluation indicators, and the original data matrix is ​​obtained:

[0229] X=(x ua ) p×q

[0230] Where X represents the original data matrix; (x ua ) p×q represents a matrix with p rows and q columns; p represents the number of evaluation objects, that is, the number of underground coal gasification areas to be evaluated; q represents the number of evaluation indicators, that is, the total number of various parameter indicators used for evaluation; x ua It represents the original value of the u-th evaluation object with respect to the a-th indicator; u represents the serial number of the evaluation object, and its value range is 1, 2, ..., p; a represents the serial number of the evaluation indicator, and its value range is 1, 2, ..., q.

[0231] Normalize the original matrix to get the normalized matrix:

[0232]

[0233] R=(r ua ) p×q

[0234] Among them, r ua represents the standardized value of the ath indicator of the uth evaluation object in the standardized matrix; x ua Represents the original value of the ath indicator of the uth evaluation object in the original data matrix; It represents the sum of the squares of the original values ​​of all evaluation objects u under the same indicator a from u=1 to p; R represents the normalized matrix.

[0235] Specific implementation method: To eliminate the influence of different indicator dimensions, the original data needs to be standardized. For each column of data (the same indicator), calculate the square root of the sum of the squares of the indicator values ​​of all evaluated objects, and then divide each original value by this square root to obtain the standardized value.

[0236] For example, for indicator a, calculate: Then use each x uv Divide by this value to get the normalized r ua .

[0237] Step 203: Determine indicator weights and a weighted standardized decision matrix;

[0238] Specifically, let the indicator weight vector be:

[0239] W e =(w1, w2, ..., w q )

[0240]

[0241] Among them, W e Indicates the indicator weight; W1, w2, w q Respectively represent the weights of the 1st, 2nd, and qth evaluation indicators; q represents the total number of evaluation indicators; Represents the sum of all weights.

[0242] It should be noted that W e The same weight distribution as in Example 1 may be adopted.

[0243] Compute the weighted normalized decision matrix:

[0244] v ua =w a ×r ua

[0245] V=(v ua ) p×q

[0246] Among them, v ua represents the weighted normalized value of the ath indicator of the uth evaluation object in the weighted normalized matrix; w a Indicates the weight value of the ath evaluation index; r ua represents the standardized value of the ath indicator of the uth evaluation object in the standardized matrix; V represents the weighted standardized decision matrix; V represents the weighted standardized decision matrix; p represents the number of evaluation objects, that is, the number of underground coal gasification areas to be evaluated; q represents the number of evaluation indicators, that is, the total number of various parameter indicators used for evaluation.

[0247] Specific implementation method: Multiply each element in the normalization matrix by the weight of the corresponding indicator to obtain the weighted normalization decision matrix. For example, for the element r in the normalization matrix ua , and its weighted value is v ua =w a ×r ua , where w a is the weight of indicator a.

[0248] Step 204: Determine an ideal solution and a negative ideal solution;

[0249] Positive ideal solution:

[0250]

[0251] Among them, V + represents the positive ideal solution vector; They represent the optimal values ​​of the 1st, 2nd, and qth indicators in the positive ideal solution vector respectively; q represents the total number of evaluation indicators.

[0252] For benefit indicators:

[0253]

[0254] in, represents the optimal value of the ath index in the positive ideal solution vector; maxv ua It represents the maximum value of the weighted normalized value of indicator a among all evaluation objects u;

[0255] For cost-based indicators:

[0256]

[0257] in, represents the optimal value of the ath index in the positive ideal solution vector; minv ua It represents the minimum value of the weighted normalized value of indicator a among all evaluation objects u.

[0258] Negative ideal solution:

[0259]

[0260] Among them, V - represents the negative ideal solution vector; They represent the worst values ​​of the 1st, 2nd, and qth indicators in the positive ideal solution vector, respectively, and q represents the total number of evaluation indicators.

[0261] For benefit indicators:

[0262]

[0263] in, Indicates the worst value of the ath index in the negative ideal solution vector; minv ua It represents the minimum value of the weighted normalized value of indicator a among all evaluation objects u;

[0264] For cost-based indicators:

[0265]

[0266] in, Indicates the worst value of the jth index in the negative ideal solution vector; maxv ua It represents the maximum value of the weighted normalized value of indicator a among all evaluation objects u;

[0267] A benefit-type indicator is one in which the larger the value, the better; a cost-type indicator is one in which the smaller the value, the better.

[0268] Specific implementation method: For each indicator (column) in the weighted standardized decision matrix V, an ideal solution and a negative ideal solution are determined based on the indicator type. For benefit-oriented indicators (larger values ​​are preferred), the positive ideal solution is the maximum value in that column, and the negative ideal solution is the minimum value in that column. For cost-oriented indicators (smaller values ​​are preferred), the positive ideal solution is the minimum value in that column, and the negative ideal solution is the maximum value in that column. In underground coal gasification evaluation, all eight indicators are benefit-oriented, meaning that larger values ​​indicate greater suitability.

[0269] Step 205: Calculate the distance from each evaluation object to the ideal solution and the negative ideal solution;

[0270] The distance between each evaluation object and the positive ideal solution:

[0271]

[0272] in, represents the distance from the u-th evaluation object to the positive ideal solution; represents the sum of all indices a from a=1 to q; v ua Represents the weighted normalized value of the ath indicator of the uth evaluation object in the weighted normalized matrix; Represents the optimal value of the ath index in the positive ideal solution vector.

[0273] The distance between each evaluation object and the negative ideal solution:

[0274]

[0275] in, represents the distance from the u-th evaluation object to the negative ideal solution; represents the sum of all indices a from a=1 to q; v ua Represents the weighted normalized value of the ath indicator of the uth evaluation object in the weighted normalized matrix; Represents the worst value of the ath index in the negative ideal solution vector.

[0276] Specific implementation method: For each evaluation object, calculate the Euclidean distance between its weighted standardized value and the positive ideal solution and the negative ideal solution. Euclidean distance is a measure of the distance between two points in multidimensional space, expressed as the square root of the sum of the squares of the differences between the coordinates of the two points. For the evaluation object u, calculate the square root of the sum of the squares of the differences between the weighted standardized values ​​of all its indicators and the positive ideal solution to obtain its distance to the positive ideal solution. Similarly, calculate the distance to the negative ideal solution

[0277] Step 206: Calculate the relative proximity of each evaluation object and determine the suitability level;

[0278] Relative proximity:

[0279]

[0280] Among them, C u is the relative proximity of the u-th evaluation object, with a value range of (0, 1); represents the distance from the u-th evaluation object to the negative ideal solution; represents the distance from the u-th evaluation object to the positive ideal solution;

[0281] Relative proximity C u The larger the value (i.e., the comprehensive suitability coefficient in Example 1), the closer the evaluation object is to the ideal solution and the further away it is from the negative ideal solution, that is, the more suitable it is for underground coal gasification.

[0282] The suitability levels are as follows:

[0283] C u ≥0.9: very suitable;

[0284] 0.8≤C u <0.9: quite suitable;

[0285] 0.6≤C u <0.8: generally suitable;

[0286] 0.4≤C u <0.6: less suitable;

[0287] C u <0.4: unsuitable;

[0288] Implementation: For each evaluation object, relative proximity is calculated using its distance to the positive ideal solution and the negative ideal solution. Relative proximity is a value between 0 and 1. Values ​​closer to 1 indicate a closer evaluation object to the ideal solution, while values ​​further from the negative ideal solution indicate a higher suitability. Based on the calculated relative proximity and against the suitability grading criteria, the suitability grade of each evaluation object is determined.

[0289] Compared with the suitability evaluation method in Example 1, this example uses the TOPSIS method as an evaluation method, and the main improvements are:

[0290] While Example 1 can only evaluate the suitability of a single region, the TOPSIS method can simultaneously evaluate multiple potential gasification regions and give a clear ranking, making it easier for decision makers to select the optimal solution among multiple candidate regions, thus solving the problem of simultaneous evaluation and ranking of multiple regions.

[0291] The concepts of ideal solution and negative ideal solution are introduced. By calculating the distance between the evaluation object and the ideal solution (optimal solution) and the negative ideal solution (worst solution), the relative advantages and disadvantages of each evaluation object can be more objectively reflected.

[0292] The standardization process eliminates the impact of different indicator dimensions, making the evaluation results between different regions more comparable.

[0293] The above describes an embodiment of the present invention, but this embodiment is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Ordinary technicians in this field can also make more forms of equivalent embodiments based on the inspiration of this embodiment, all of which are protected by this embodiment.

Claims

1. A multi-parameter collaborative evaluation method for underground coal gasification site selection, characterized in that: The steps include: Collect and review coal resource data in the target area, and screen and analyze influencing factors; Compare the collected coal resource data with the corresponding influencing factor evaluation standards to obtain the estimated values ​​of each factor of the corresponding influencing factors; According to the valuation of each factor of the influencing factors in the target area, the suitability coefficient of each factor and the average suitability coefficient of the influencing factors are calculated; Based on the average suitability coefficient of each influencing factor in the target area and the weight of each influencing factor, calculate the weighted suitability coefficient of each factor; Calculate the comprehensive suitability coefficient of the target area based on the weighted suitability coefficients of each factor; The comprehensive suitability coefficient and suitability grade classification standard are compared to evaluate the suitability of underground coal gasification in the coal seams in the target area.

2. The method for underground coal gasification site selection based on multi-parameter collaborative evaluation according to claim 1, characterized in that: The coal resource data include: coal seam occurrence conditions, geological structure conditions, hydrogeological conditions, engineering geological conditions, coal quality conditions, coal gasification performance, industrial economic efficiency and environmental geological conditions.

3. The method for underground coal gasification site selection based on multi-parameter collaborative evaluation according to claim 1, characterized in that: The calculation formula of factor suitability coefficient is: Among them, E represents the factor suitability coefficient, which is a dimensionless index to measure the suitability of each evaluation factor. Its value range is [0,1]. The closer the value is to 1, the more suitable the factor is for underground coal gasification. F v F is the valuation of each factor of the influencing factors; max The maximum value assigned to the suitability; The calculation formula for the average suitability coefficient is: Among them, E p is the average suitability coefficient of each influencing factor; n is the total number of factors under a certain influencing factor; E i is the suitability coefficient of the i-th factor; It represents the sum of the fitness coefficients of all factors.

4. The method for underground coal gasification site selection based on multi-parameter collaborative evaluation according to claim 1, characterized in that: The calculation formula of weighted suitability coefficient is: AND pw =And p ×W; Among them, E pw is the weighted suitability coefficient of each factor, E p is the average suitability coefficient of each influencing factor; W is the weight of each influencing factor, indicating the importance of the factor in the evaluation system; The calculation formula for the comprehensive suitability coefficient is: Among them, E z The comprehensive suitability coefficient indicates the overall suitability of the coal seams in the target area for underground coal gasification. It is the final quantitative indicator of the evaluation results and has a value range of [0,1]. The closer the value is to 1, the more suitable the area is for underground coal gasification projects. represents the weighted suitability coefficient of the jth influencing factor; represents the sum of all weighted fitness coefficients.

5. The method for underground coal gasification site selection based on multi-parameter collaborative evaluation according to claim 1, characterized in that: The suitability classification standards are as follows: Comprehensive suitability coefficient ≥0.9 is very suitable; 0.8≤comprehensive suitability coefficient<0.9 is relatively suitable; 0.6≤comprehensive suitability coefficient<0.8 is generally suitable; 0.4≤comprehensive suitability coefficient<0.6 is relatively unsuitable; A comprehensive suitability coefficient <0.4 is unsuitable.

6. The method for underground coal gasification site selection based on multi-parameter collaborative evaluation according to claim 1, characterized in that: The TOPSIS method is used to calculate the comprehensive suitability coefficient, which includes the following steps: Constructing a standardized decision matrix; Determine indicator weights and weighted standardized decision matrix; Determine ideal solutions and negative ideal solutions; Calculate the distance from each evaluation object to the ideal solution and the negative ideal solution; Calculate the comprehensive suitability coefficient of each evaluation object.

7. The method for underground coal gasification site selection based on multi-parameter collaborative evaluation according to claim 6, characterized in that: The standardization processing formula in constructing the standardization decision matrix is: R＝(r ua ) p×q ； Among them, r ua represents the standardized value of the ath indicator of the uth evaluation object in the standardized matrix; x ua Represents the original value of the ath indicator of the uth evaluation object in the original data matrix; represents the sum of the squares of the original values ​​of all evaluation objects u under the same indicator a from u = 1 to p; R represents the normalized matrix; The weighted normalization matrix is: V ua =w a ×r ua ; V=(v ua ) p×q ; Among them, v ua represents the weighted normalized value of the ath indicator of the uth evaluation object in the weighted normalized matrix; w a Indicates the weight value of the ath evaluation index; r ua represents the standardized value of the ath indicator of the uth evaluation object in the standardized matrix; V represents the weighted standardized decision matrix; V represents the weighted standardized decision matrix; p represents the number of evaluation objects, that is, the number of underground coal gasification areas to be evaluated; q represents the number of evaluation indicators, that is, the total number of various parameter indicators used for evaluation.

8. The method for underground coal gasification site selection based on multi-parameter collaborative evaluation according to claim 1, characterized in that: The weights of the various influencing factors are adjusted according to the characteristics of coal resources in different regions.

9. A multi-parameter collaborative evaluation underground coal gasification site selection system, used to implement the multi-parameter collaborative evaluation underground coal gasification site selection method according to claims 1-9, characterized in that: include: Data acquisition module, used to collect and review data on the occurrence conditions, geological structure conditions, hydrogeological conditions, engineering geological conditions, coal quality conditions, coal gasification performance, industrial economic factors and environmental geological conditions of the coal seams in the project area; The data processing module is used to compare the collected data with the preset evaluation criteria, obtain the valuation of each factor of the corresponding influencing factors, and calculate the suitability coefficient of each factor of the influencing factors and the average suitability coefficient of the influencing factors; Evaluation calculation module, used to calculate the weighted suitability coefficient of each factor and the comprehensive suitability coefficient or relative proximity of the project area according to the weight of each influencing factor; The result judgment module is used to evaluate the suitability level of underground coal gasification in the coal seams in the project area based on the comprehensive suitability coefficient or relative proximity, and classify the evaluation results into grades; The user interface module is used to display the evaluation results and provide data input, parameter adjustment and result export functions.

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