蓄热相变对煤体渗透率的影响作用研究

Study on effect of thermal storage phase change on coal permeability

为研究热环境下液固膨胀相变对煤体增透的作用,在蓄热相变对煤体增透实验的基础上,获取了蓄热相变作用下煤体渗透率和T2弛豫时间谱变化特征,分析了蓄热相变作用对煤体渗透率和孔裂隙结构的影响。研究结果表明:蓄热相变作用下煤体渗透率增幅最大达到150.8%,蓄热相变作用所提供的热环境可以促进相变膨胀对煤体增透的效应;煤体T2弛豫时间在10~50 ms之间和100 ms左右的谱峰值上升较高,增幅分别为15.36%及18.03%,且介于2个谱峰之间的T2值增幅最大达到47.11%,蓄热相变主要通过增加中大孔和裂隙的数量以及两者之间孔裂隙结构的连通性进而增加煤体的渗透率。

In order to study the effect of liquid-solid expansion phase change on coal permeability enhancement under thermal environment, based on the experiment of increasing the permeability of coal by thermal storage phase change, the characteristics of coal permeability and T2 relaxation time spectrum changes under the effect of thermal storage phase change are obtained, and the effects of thermal storage phase change on coal permeability and pore structure were analyzed. The research results show that the maximum increase in coal permeability under the effect of thermal storage phase change reaches 150.8%, the thermal environment provided by the thermal storage phase change can promote the effect of phase change expansion on the increase of the coal permeability. The peak of the coal body T2 relaxation time between 10 ms and 50 ms and about 100 ms rises relatively higher, the increase is 15.36% and 18.03%, and the maximum increase of the T2 value between the two peaks is 47.11%. The thermal storage phase change mainly increases the permeability of coal by increasing the number of medium and large pores and cracks,and the structure connectivity between the two.