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Feasibility Evaluation Parameters and Analysis Coal mine gas drainage and CBM development is the development of coal seam gas in two different ways, the main purpose of underground gas drainage is provide a safe working environment to coal production. The majority of CBM extraction is to develop resources, access to economic Efficiency, there are also very different of these methods in the extraction sites, extraction technique and extraction technology and other aspects. At present, domestic and international underground gas drainage and ground coalbed methane development are mostly evaluated separately, not from the dual perspective of security and resource development method will work closely with both the comprehensive evaluation, and therefore no corresponding evaluation methods and evaluation criteria, leading to a single technology of the evaluation, a single evaluation of the content, lacking of long-term consideration and poor adaptability in coal mining areas. The work, according to domestic and international surface and underground exploration and development of coalbed methane gas extraction evaluation of the experiences of integrated coal seam gas drainage district assessment methods and evaluation research, and the largest Buddhist temple Mine coal seam gas can be carried out extraction of Evaluation.
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Evaluation Parameters CBM extraction is mainly affected by structural complexity, coal thickness, gas content, coal structure, coal permeability, reservoir pressure and other geological factors, the methane can be collected depends on the efficient allocation and Combination of these geological indicators. Underground gas drainage is also subject to structural complexity of the coal structure, coal thickness, gas content, gas pressure and other geological factors. Structural complexity and coal structure determine the feasibility of underground drilling construction, the complex construction zone or mylonitic coal, There is difficulties in construction in the gas distribution of crushed coal, the process of drilling accident prone sticking; the poor area of coal structure, low permeability coal seams, gas-flow difficulties, difficult extraction; coal seam thickness, gas content directly affects the abundance of coal seam gas, gas drainage volume of coal seam gas content of thin or small, underground gas drainage volume To small; the higher the gas pressure, gas extraction of the effective pressure on the greater gas output more easily.
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The evaluation parameters of Parameter Analysis.
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1 Coal Layer Development. Dafosi Coal Mine Gas Drainage ground the main objective of 4 and 4 on the coal seam, in some areas and 4 -1 4 -2 on the coal seam can also be referred to as the target coal seam gas drainage. Among them, 4 and 4 on the coal seam pitch is 5 ~ 35m, usually 5 ~ 20m, Ida's in - the western region is less than 15m (Figure 1). 0.
DOI: 10.14264/uql.2015.1105
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0km Figure 1 4 and 4 on the coal seam pitch contour.
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2 Gas Content. The coal seam gas content is high in Dafosi mine, which is negative to the safety of coal mine, but for the purpose of energy development and utilization of coal bed methane extraction is more favorable. Seam gas content is usually in 2 ~ 3m3 / t, geological exploration drilling during the coring test gas content of up to 5. 57 m3 / t (dry and ash-free basis for the 6. 29m3/t. daf); in the construction of the underground 8 gas drilling test parameters, test the gas content is 1. 06 ~ 3. 28 m3 / t, an average of 1. 82 m3 / t, consistent with the ground test results. Coal in our contemporary, the gas content is high.
DOI: 10.3389/fenrg.2022.1096539
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3 Coal Layer Permeability. Research area for the permeability of coal seams in the gas parameter testing project, carried out some exploratory tests. Include: ①gas pressure test gas drill holes The work of Lane in the 40, 108 shipped by just drilling gas drill holes completed sealing, the gas pressure test, the relative gas pressure to 0. ②driving test and analysis of the influence to open up Bedding in the 40106 grouting drilling DFSX07, and sealing the gas pressure test, test the relative gas pressure of 0, gas content 1. 03m3 / t. Analysis, filling the hole in the 40106 and 40108 Lane of Lane between transport, due to transport 40, 108 40, 106 filling Lane of Lane and the close proximity of the two tunneling of stress release, resulting in coal seam gas desorption, gas pressure and gas content decreased . ③ drill test the gas content at different depths The work for the study of the gas content of coal mining and Mine coal seam permeability of the situation in 4 coal seam on the 2nd return airway construction drilling, drilling of gas content measurements at different depths Test, test results in Table 1. Table 1 Seam gas drilling depth determination of the different data tables Drilling Sample ID Core depth (m) air dried basis Gas content (m3/t) dry ash-free basis gas content (m3/t) Dfsx13 Dfsx13-1.
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65 Dfsx13-2.
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31 Dfsx13-3.
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49 Dfsx13-4.
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06 Dfsx15 Dfsx15-1.
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29 Dfsx15-4.
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59 The results show that the drilling depth is significantly affected the gas content of coal seam , to a certain depth range, with the drilling depth increases, the trend of the coal seam gas content was gradually increasing. On the one hand, that roadway development play a significant impact in coal seam gas content, in the drilling depth of about 60m, the content of coal seam gas basic stable. On the other hand, with core depth changes, coal seam gas content changes rapidly, and in relatively A large depth range of gas content was stable, were indicative of good permeability of coal seams.
DOI: 10.2118/29577-ms
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4 Date Analog of Storage Layer. Analysis the geological conditions of coal seam gas area, as well as China's current status of coal seam gas exploration and development, according to a single well controlled area 0. 09km2, 330 days of production time per year, on the whole mine field, and the favorable evaluation of coal seam gas blocks and blocks more favorable Simulated coal gas drainage prediction. The predicted results of Large Buddhist Temple mine are in Figure2. Figure 2 Dafosi Coal Mine Gas Drainage curves of simulation and prediction of gas production Simulation forecast also shows that different years and different effects of coal seam gas extraction are greatly different (Table 2). 4, the amount of coal seam gas extraction is the main contribution to the coal seam, with the extend of extraction time, the coal seam gas extraction rate has improved greatly. All Ida simulation predicted that 10 years of continuous production of gas wells, 4 on the volume of coal seam gas extraction 16. 53 × 104m3, gas accounted for 10. 86% of total recovery, gas extraction rate of 33. 02%; 4 coal seam gas drainage volume of 135. 65 × 104m3, extraction rate of 35. 74%, accounting for the total gas recovery 89. 14%. Continuous production for 15 years, 4 on the volume of coal seam gas extraction 23. 83 × 104m3, gas accounted for 11. 10% of total recovery, gas extraction rate of 47. 60%; 4 coal seam gas drainage volume of 190. 84 × 104m3, accounting for gas recovery Total 88. 90%, 50. 28% extraction rate. Table 2 Simulation predict the service life of coal seam gas extraction in different gas fact sheet Coal number 10 years 15 years Total amount of recovery (104m3) Proportion (%) Pumping rate (%) Total amount of recovery (104m3) Proportion (%) Pumping rate (%) 4up# coal.
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60 4# coal 135. 65.
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74 190. 84.
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28 Total 152. 18 100.
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68 214. 67 100.
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General Evaluation Dafosi Mine coal layer growth layers can be more shallow coal seams, the main coal seam stability, thickness, coal structure is superior, the coal seam permeability and gas content is high, underground gas parameter testing has shown that 4 and 4 on the seam Belong to drainage in coal, the geological conditions for coal bed methane extraction is better and the CBM testing results in this area ground are better. The ground being implemented in two coal-bed methane wells butt test, the highest gas production well No. 1 to 1100m3 / d; underground gas drainage is very good, underground gas drainage volume in 2008 to 34, 654, 700 m3, a Gas drainage rate as high as 94.
DOI: 10.1021/acs.energyfuels.1c04266.s001
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Conclusion At present, the main gas extraction method is underground coal mine gas extraction, which aims to reduce the gas content, to provide security for the coal mining production environment, but the interface existence between underground gas drainage and coal production, and the coal permeability in Dafosi Ida is good, Low concentration of underground gas drainage, only can use a single approach, and the results is poor. On the other hand, Mine coal seam gas geological conditions, reservoir conditions and resources condition in a large Buddhist temple is good, ground gas can be good drainage and surface gas extraction and coal production to avoid conflicts of convergence. Therefore, the proposed implementation of a large Buddhist temple underground mine field, ground integrated coal seam gas drainage measures to achieve effective governance and access to new energy sources, gas dual purpose. And take advantage of the current state has adopted the policy of encouraging the development of coalbed methane industry, increasing the scale of the ground coal seam gas extraction test, and the necessary testing of the gas parameters, to learn more about the area's potential for surface coal seam gas extraction, For not long time to achieve the ground in the area of coal seam gas extraction industry. Bibliography.
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