于文龙. 煤岩渗透率与有效应力耦合关系及控制机理[J]. 煤矿安全, 2018, 49(8): 10-14.
    引用本文: 于文龙. 煤岩渗透率与有效应力耦合关系及控制机理[J]. 煤矿安全, 2018, 49(8): 10-14.
    YU Wenlong. Coupling Relationship and Control Mechanism Between Coal Permeability and Effective Stress[J]. Safety in Coal Mines, 2018, 49(8): 10-14.
    Citation: YU Wenlong. Coupling Relationship and Control Mechanism Between Coal Permeability and Effective Stress[J]. Safety in Coal Mines, 2018, 49(8): 10-14.

    煤岩渗透率与有效应力耦合关系及控制机理

    Coupling Relationship and Control Mechanism Between Coal Permeability and Effective Stress

    • 摘要: 以沁水盆地南部寺河矿3#煤为研究对象,通过煤样的有效应力敏感性实验,分析了煤岩渗透率与应力的相关关系,并对煤储层渗透率与应力的耦合计算模型进行验证。研究结果表明:煤岩渗透率与有效应力具有明显相关性,随着有效应力的增加,煤岩渗透率呈负指数衰减;裂隙是影响煤储层渗透率对有效应力敏感性的重要原因,且在有效应力大于9.45 MPa以后裂隙基本闭合,导致渗透率对应力不敏感。煤岩储层应力的变化会对煤岩及其孔裂隙结构产生塑性(破坏性)变形,致使煤储层渗透率发生不可逆下降,不可逆程度多高于50%。孔裂隙塑性变形主要发生在应力敏感区和过渡区,且由应力敏感区向过渡区过渡时,衰减无因次渗透率值会出现1个“波谷”;由应力过渡区向不敏感区过渡时,衰减无因次渗透率值会出现1个“波峰”。

       

      Abstract: Taking the 3# coal in Sihe Mine in the southern of Qinshui Basin as the research object. Through the effective stress sensitivity test of coal sample, the correlation between the permeability of coal rock and stress was analyzed, and the coupling model of coal reservoir permeability and stress is verified. The results show that the permeability of coal has obvious correlation with the effective stress, and shows negative exponential decay with the increase of effective stress. Fracture plays an important role for the sensitivity of coal permeability to effective stress, and is basically closed when the effective stress is greater than 9.45 MPa, which makes the permeability less sensitive to stress. The change of stress of coal rock reservoir will produce plastic (destructive) deformation of coal rock and its pore structure, resulting in irreversible decrease of coal reservoir permeability and the degree of irreversibility is more than 50%. The plastic deformation of the fracture occurs mainly in the stress sensitive area and the transition zone, and in the transition from the stress sensitive area to the transition zone, there will be a “trough” in the attenuated non-dimensional permeability value; in the transition from the stress transition zone to the insensitive zone, the attenuated non-dimensional permeability value will have a “wave peak”.

       

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