Chen Xinjun, Zhao Shihu, Liu Zengqin, Chen Gang
State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100083, China.
Sinopec Key Laboratory of Shale Oil/Gas Exploration and Production Technology, Beijing 100083, China.
Heliyon. 2024 Jun 19;10(12):e33248. doi: 10.1016/j.heliyon.2024.e33248. eCollection 2024 Jun 30.
Underground coal gasification is of great strategic significance to the effective and clean development of coal resources and scale up production of natural gas worldwide. Selection evaluation is the foundation of the exploration and development of underground coal gasification. In this paper, the differences between mid-deep (500-2200 m) and shallow layer (<500 m) underground coal gasification are analyzed, the key parameters affecting underground coal gasification are clearly identified, and the selection evaluation technology system is established. The results show that there are great differences between mid-deep and shallow layer underground coal gasification in terms of furnace construction site selection, engineering process, gasification efficiency and gasification products, the former is the main development direction in the future considering the resource potential, gasification efficiency, environmental protection and technological progress. The research of mid-deep underground coal gasification selecting should be carried out step by step with "favorable area-favorable zone-favorable zone ranking-favorable target" evaluation system. In the early stage of exploration, the product of thickness and volatiles can be used as a rapid evaluation index. Within the suitable range, the larger the index is, the more favorable it is, and when the index is greater than 3, it is defined as the favorable area. Further, ten key geological parameters of coal seam geological conditions, coal-rock and coal-quality characteristics and structural hydrologic conditions are selected and graded during zone evaluation according to different threshold ranges. At the same time, a favorable zone queuing method based on the two-factor evaluation method is established. Additionally, the final target site selection is established with more detailed evaluation parameters, such as process performance parameters, gasification characteristics parameters, technical recoverable indicators, economic recoverable indicators. The study provides the siting selection technology for the middle deep coal underground gasification, which is of great significant for the development of coal underground gasification industry.
煤炭地下气化对煤炭资源的高效清洁开发及全球范围内天然气的规模化生产具有重大战略意义。选区评价是煤炭地下气化勘探开发的基础。本文分析了中深层（500 - 2200米）与浅层（<500米）煤炭地下气化的差异，明确了影响煤炭地下气化的关键参数，并建立了选区评价技术体系。结果表明，中深层与浅层煤炭地下气化在炉址选择、工艺流程、气化效率及气化产物等方面存在较大差异，从资源潜力、气化效率、环境保护及技术进步等方面考虑，前者是未来主要的发展方向。中深层煤炭地下气化选区研究应按照“有利区 - 有利带 - 有利带排序 - 有利目标”评价体系逐步开展。在勘探初期，可采用厚度与挥发分乘积作为快速评价指标，在适宜范围内，该指标越大越有利，指标大于3时定义为有利区。进一步地，在带评价过程中，根据不同阈值范围选取煤层地质条件、煤岩与煤质特征及构造水文条件等十个关键地质参数进行分级。同时，建立基于双因素评价法的有利带排队方法。此外，利用工艺性能参数、气化特征参数、技术可采指标、经济可采指标等更详细的评价参数进行最终目标选址。该研究为中深层煤炭地下气化提供了选址技术，对煤炭地下气化产业的发展具有重要意义。
