| 2025年中国能源消费及煤炭需求预测 |
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| 引用本文： | 褚鹏，尚德磊，李建华，等. 原位保压取心气体组分对煤层瓦斯压力测算的影响[J]. 煤田地质与勘探，2023，51(8)：79−87. DOI: 10.12363/issn.1001-1986.22.12.0939 |
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| 作者姓名： | 褚鹏 尚德磊 李建华 马少明 朱国栋 崔鹏飞 |
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| 作者单位： | 1.深圳大学 深地工程智能建造与健康运维全国重点实验室，广东省深地科学与地热能开发利用重点实验室，深地科学与绿色能源研究院，广东 深圳 518060;2.中煤科工西安研究院(集团)有限公司，陕西 西安 710077 |
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| 基金项目： | 国家自然科学基金杰出青年基金项目(52225403)；深圳市杰出青年基金项目(RCJC20210706091948015)；国家自然科学基金青年科学基金项目(52104096) |
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| 摘 要： | 基于保压取心工艺测定煤层瓦斯压力和含量，是实现瓦斯参数快速精准测定的有效方法。瓦斯是一种以甲烷为主的多组分混合气体，煤对于不同气体的吸附能力不同，混合气体中各组分气体分压也存在差异，不同气体组分占比将影响煤层瓦斯含量和压力的测算结果。为实现保压取心煤层原位瓦斯压力的精准测算，采用数值模拟和理论计算相结合，研究气体组分对瓦斯压力测算的影响。通过分析取心器内煤心瓦斯压力演化过程，将多组分气体吸附模型引入瓦斯运移理论，建立考虑多组分气体的双重介质瓦斯压力演化方程，并应用于数值仿真。模拟结果显示，煤心进入岩心筒后裂隙瓦斯压力初始先迅速下降而后逐渐上升，基质瓦斯压力一直缓慢下降，岩心筒内自由空间的瓦斯压力由初始0.1 MPa缓慢上升，数小时后3个压力平衡，平衡压力远小于煤心原始瓦斯压力；CO2组分对平衡瓦斯压力值的影响最大，当气体为纯CH4时平衡压力最小。同时，推导了考虑多组分气体的保压取心煤层原位瓦斯压力计算公式，根据设定的平衡压力反算煤层瓦斯压力，理论计算煤层瓦斯压力值与数值模拟数据的对比结果吻合较好，Pearson相关系数为99.89%；利用取心器平衡压力反算煤层瓦斯压力时，计算结果随CO2、CH4组分增加和N2组分减少而减小，气体为纯CH4时反算的煤层瓦斯压力值最小。利用保压取心测算煤层原位瓦斯压力时，若不考虑气体组分而以纯CH4计算，可能会低估煤层瓦斯压力值，尤其是煤层瓦斯压力较大且CO2气体组分占比高时，误差更大，为准确测算煤层瓦斯压力，应考虑瓦斯气体组分的影响。
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| 关 键 词： | 保压取心 气体组分 煤层瓦斯压力 瓦斯运移 |
| 收稿时间： | 2022-12-09 |
| 修稿时间： | 2023-05-16 |
Prediction on the energy consumption and coal demand of China in 2025 |
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| CHU Peng，SHANG Delei，LI Jianhua，et al. Influence of gas components on the determination of gas pressure in coal seams under in-situ pressure-preserved coring[J]. Coal Geology & Exploration，2023，51(8)：79−87. DOI: 10.12363/issn.1001-1986.22.12.0939 |
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| Authors: | CHU Peng SHANG Delei LI Jianhua MA Shaoming ZHU Guodong CUI Pengfei |
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| Affiliation: | 1.State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization, Institute of Deep Earth Sciences and Green Energy, Shenzhen University, Shenzhen 518060, China;2.CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China |
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| Abstract: | Determining the pressure and content of coal seam gas based on pressure-preserved coring is an effective method for quickly and accurately calculating gas parameters. Coal seam gas is a multi-component gas mixture dominated by methane. Given that coals show different adsorption capacities for different gases and that the components in the mixed gas exhibit different partial pressures, the proportions of gas components can influence the calculation results of the content and pressure of coal seam gas. To accurately determine the in-situ gas pressure in coal seams based on the pressure-preserved coring, this study investigated the influence of gas components on the determination of gas pressure by combining numerical simulation with theoretical calculation. Based on the analysis of the evolutionary process of coal-core gas pressure in the coring device, this study introduced an adsorption model for multi-component gas into the gas migration theory. Then, we developed an equation for the evolution of dual-medium gas pressure considering the effects of multicomponent gas and applied this equation to numerical simulation. The numerical simulation results are as follows: (1) After coal cores entered the core barrel, the gas pressure in fissures decreased rapidly and then increases gradually, the gas pressure in the matrix decreased slowly, and the free-gas pressure in the core barrel rose gradually from the initial 0.1 MPa. The three pressures reached equilibrium after a few hours, with the gas pressure after equilibrium being much less than the initial pressure of coal cores. (2) The CO2 component had the greatest impact on the gas pressure after equilibrium, which, however, was the lowest for gas consisting only of pure CH4. Furthermore, this study deduced an equation for calculating in-situ gas pressure in coal seams based on the pressure-preserved coring that considers the effects of multi-component gas. For the gas pressure in coal seams obtained through the reverse calculation based on the set gas equilibrium pressure, it agreed well with the data from numerical simulation, with a Pearson correlation coefficient of 99.89%. For the gas pressure in coal seams determined through the reverse calculation based on the equilibrium pressure in the coring device, it decreased with increased CO2 or CH4 component and decreased N2 component and reached the minimum for coal seam gas consisting only of pure CH4. Therefore, when determining the in situ gas pressure in coal seams based on pressure-preserved coring assuming that coal seam gas consists only of pure CH4, the determined in-situ gas pressure in coal seams may be underestimated, especially in the case of a high proportion of the CO2 component. Therefore, to accurately determine the gas pressure in coal seams, it is necessary to consider the influence of the components of coal seam gas. |
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| Keywords: | pressure-preserved coring gas component gas pressure in coal seams gas migration |
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