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基于NMR的类煤模型材料渗流性能与原煤相似性评估方法

Evaluation method of permeability performance and similarity of raw coal based on NMR coal model materials

  • 摘要: 物理模型试验是揭示煤岩动力灾害作用机制的重要研究手段,而类煤物理模型材料的配制是相似煤层铺设的关键。针对流固耦合失温类动力灾害(例如煤与瓦斯突出、突水等),模拟材料的渗流性能是试验的关键。为合理评估模拟材料渗流性能与原煤的相似性,提出利用加卸载过程材料孔裂隙结构与渗透率的Pearson相关系数进行相似性评估的方法,并配置了类煤材料进行试验验证。结果表明:相关系数P能够有效反映加卸载过程中原煤与类煤材料的渗流性能的相似性,2种煤样的渗流孔孔隙率、渗透率和渗流孔可压缩性系数(CP)的最小相关系数分别为0.624、0.913和0.888,渗流性能在整体变化上保持强相似或极强相似;在加卸载过程中,2种煤样的孔隙率和渗透率均与围压呈负相关,且渗透率对应力的敏感性较高;2种煤样的CP与围压呈负相关,且卸载过程中的CP高于加载过程中的CP。研究成果为类煤物理模型材料渗流性能相似性评估提供依据,对开展物理模型试验研究具有指导意义。

     

    Abstract: Physical model experiments are an important research method to reveal the mechanism of coal rock dynamic disasters, and the preparation of coal like physical model materials is the key to laying similar coal seams. For dynamic disasters such as coal and gas outbursts, water inrush, etc. caused by fluid solid coupling and temperature loss, simulating the permeability performance of materials is the key to the experiment. To reasonably evaluate the similarity between simulated material permeability and raw coal, a method of using Pearson correlation coefficient between material pore structure and permeability during loading and unloading process for similarity evaluation was proposed, and coal like materials were configured for experimental verification. The results showed that: Correlation coefficient P can effectively reflect the similarity of the permeability performance between raw coal and coal like materials during the loading and unloading process. The minimum correlation coefficients P for the porosity, permeability, and compressibility coefficient (CP) of the two coal samples were 0.624, 0.913, and 0.888, respectively. The permeability performance remained strongly similar or extremely similar in overall changes. During the loading and unloading process, the porosity and permeability of both coal samples are negatively correlated with confining pressure, and the permeability is highly sensitive to stress. CP of the two coal samples is negatively correlated with confining pressure, and CP value during unloading is higher than that during loading. The research results provide a basis for evaluating the similarity of permeability performance of coal like physical model materials, and have guiding significance for conducting physical model experimental research.

     

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