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| 不同相态CO2吸附作用下煤体渗流特性研究 |
| Study on the seepage characteristics of coal under the adsorption of CO2 in different phases |
| 投稿时间：2024-01-26 修订日期：2024-08-13 |
| DOI： |
| 中文关键词: 不同相态CO2吸附 地质封存 渗流特性 煤 |
| 英文关键词:Adsorption of carbon dioxide in different phases Geological sealing Seepage characteristics coal |
| 基金项目:国家自然科学基金面上项目(51874165)；辽宁省兴辽英才计划项目(XLYC1902106)；内蒙古科技重大专项(2021ZD0034-2)资助。 |
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| 中文摘要: |
| 针对不同相态CO2注入难开采煤层发生的物理及化学反应对储层渗流特性影响规律变化不明的难题。以内蒙古敏东一矿矿区为例,将煤样放入自制的三轴吸附渗透仪中,通过调控温度和压力进行不同相态CO2对煤样的吸附试验,模拟在复杂地应力条件下不同相态CO2在难开采煤层的吸附过程。测量了吸附后煤样的波速和渗透率,依据裂隙隔断效应表征了CO2对煤体的劣化程度,得到了渗透率与孔隙压力、有效应力间的关系,揭示了一些新的规律：(1)煤体吸附CO2时,内部裂隙扩大并连通,导致煤体的声波传播速度与CO2注入压力呈负相关。(2)随相态由气态至液态再至超临界态的转变,煤体的声波衰减率逐渐增大,最大声波衰减率为33.1％,煤体内部渗流通道得到改善。(3)煤样的渗透率受吸附CO2相态的不同和有效应力的变化影响。(4)渗透率随煤样吸附CO2相态由气态至液态再到超临界态的转变逐渐增大。 |
| 英文摘要: |
| The problem of unclear changes in the physical and chemical reactions that occur when CO2 is injected into difficult to exploit coal seams with different phase states, affecting the reservoir seepage characteristics. Taking the Mindong No.1 mining area in Inner Mongolia as an example, coal samples were placed into a self-made triaxial adsorption permeameter, and adsorption experiments were conducted on different phase states of CO2 on coal samples by adjusting temperature and pressure. The adsorption process of CO2 in different phase states in difficult to mine coal seams was simulated under complex geological stress conditions. The wave velocity and permeability of the adsorbed coal sample were measured, and the degree of degradation of CO2 on the coal body was characterized based on the fracture isolation effect. The relationship between permeability, pore pressure, and effective stress was obtained, revealing some new laws: (1) When the coal body adsorbs CO2, the internal fractures expand and connect, resulting in a negative correlation between the sound wave propagation speed of the coal body and the CO2 injection pressure. (2) As the phase transitions from gas to liquid and then to supercritical, the acoustic attenuation rate of coal gradually increases, with a maximum acoustic attenuation rate of 33.1%. The internal seepage channel of coal is improved. (3) The permeability of coal samples is influenced by the different adsorbed CO2 phases and changes in effective stress. (4) The permeability gradually increases with the transition of CO2 adsorption phase from gas to liquid and then to supercritical state in coal samples. |
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