CO2地质埋藏深度对高阶煤孔隙结构的影响

Influences of burial depth on pore structure of high-rank coal during the CO2 storage process

  • 摘要: 高阶煤中的CO2地质埋藏具有存储CO2和提高煤层气采收率的双重意义。通过压汞测试和低温液氮吸附实验对经过CO2地质埋藏模拟实验处理前后的煤样品进行分析测试,探讨了不同埋藏深度下煤中孔隙演化的特征与机理。研究表明:煤的真密度、视密度、孔隙体积、煤基质体积变化、有机质膨胀与收缩等参数均表现出不同的演化特征;埋藏过程中温度压力的增大对H2O–CO2–煤的地球化学反应效应的影响并非线性,而是存在一个对孔隙特别是微孔孔容和比表面积改造最大的深度范围,该深度将使得高阶煤孔隙结构得到最佳的改造效果,从而进一步更有利CO2的地质埋藏和提高煤层气的采收率。

     

    Abstract: CO2 storage into deep high rank coal has the positive effect on enhancing the CH4 recovery and sealing the CO2. The samples before and after the CO2 storage simulation experiments were analyzed by Mercury porosemitry and low temperature liquid adsorption, the pore structure evolution characteristics of CO2 storage in different burial depth was discussed. The results show that the true density, bulk density, pore volume, coal matrix volume changes, swelling and contraction of coal are all suffering from different evolution features. The influence of depth on geochemical reaction is not a linear relationship. A maximum depth that has significant influences on micropores and specific area exists. This burial depth is best for the reconstruction of pore systems in coal and more favorable for CH4 recovery and CO2 geological storage.

     

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