• 论文
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
注热蒸汽后的煤体微观孔裂隙演化规律
  • Title

    Evolution law of microscopic pore fractures of coal after hot steam injection

  • 作者

    李永林柏泉杨凯朱传杰孔佳

  • Author

    LI Yong,LIN Baiquan,YANG Kai, ZHU Chuanjie,KONG Jia

  • 单位

    中国矿业大学 煤矿瓦斯与火灾防治教育部重点实验室中国矿业大学 安全工程学院

  • Organization
    1.Key Laboratory of Coal Methane and Fire Control,Ministry of Education,China University of Mining and Technology,Xuzhou ,China;2.School of Safety Engineering,China University of Mining and Technology,Xuzhou ,China
  • 摘要

    我国煤层瓦斯赋存具有强吸附、低渗透、微孔隙的特点,注热蒸汽开采作为一种新的增加瓦斯抽采率的方法,存在的热蒸汽作用于煤体后的瓦斯解吸、孔隙结构改变等一些基础问题仍未探讨。为了揭示热蒸汽对煤体孔裂隙结构的影响作用,使用高温热蒸汽对煤样进行处理,并借助扫描电镜、压汞法和核磁共振测试手段探讨了热处理前后煤样的孔裂隙演化规律。试验结果表明:热蒸汽作用后的煤体孔隙结构演化归结为4种基本模式,分别为孔隙扩张模式、孔隙连通模式、孔隙破裂模式和裂隙贯通模式。热蒸汽处理后,2种煤样进退汞差值均变大,总孔容、渗透率、孔隙率和平均孔径得到了显著提升;表明蒸汽作用后煤开放孔变多,闭合孔和半闭合孔减少,T2谱中的波峰P1、P2和弛豫时间、整体峰谱面积均有显著提高,表明蒸汽作用后煤孔隙结构受热效应、水蒸气疏孔的影响,孔隙由中小孔向中大孔转变,孔裂隙连通性增加。原有的孔隙得到了进一步发育,孔隙结构的改变能促进煤体的扩孔增渗,最终有利于瓦斯在煤体内的解吸与渗流。对于注热增渗等技术的的进一步发展具有较好的基础作用,研究内容为下一步蒸汽作用后瓦斯解吸研究有很好的指导作用,为注热蒸汽提高煤层渗透率,进而提高煤层气抽采率提供了依据。

  • Abstract
    Coal seam gas occurrence in China has the characteristics of strong adsorption, low permeability and micro-pore.The hot steam injection is a new way to increase the gas extraction rate.However, some basic problems such as gas desorption and pore structure change have not been explored.In order to reveal the effect of hot steam on the pore structure of coal pores, the pore fissure evolution rules of coal samples before and after heat treatment were discussed by means of scanning electron microscopy (SEM),mercury injection and nuclear magnetic resonance (NMR).The experimental results show that the pore structure evolution of coal after thermal steaming action can be summarized into four basic models, namely pore expansion mode, pore connectivity mode, pore fracture mode and fracture penetration mode.After the hot steam treatment, the difference between the inlet and outlet of the two coal samples was larger, and the total pore volume, permeability, porosity and average pore size were significantly improved.It shows that after steaming, the open pores of coal became more and the closed and semi-closed pores decreased.The peak P1、P2, relaxation time and overall peak area of T2 spectrum were significantly improved, indicating that the pore structure of coal splitting was affected by heat after steam action, and the pores changed from medium to small holes to medium and large holes, and pore fracture connectivity also increased.The original pores have been further developed, and the change of pore structure can promote the expansion and permeability of the coal body, which is beneficial to the gas desorption and seepage of gas in coal.It has a good foundation for the further development of technologies such as heat injection and infiltration.The research provides aguidance for improving the permeability of coal seam and the extraction rate of coal seam gas by injecting hot steam.
  • 关键词

    煤体热蒸汽孔裂隙扫描电镜压汞核磁共振

  • KeyWords

    coal;hot steam; pore fracture; SEM; mercury injection; NMR

  • 基金项目(Foundation)
    国家自然科学基金资助项目(51474211);国家重点研发计划资助项目(2016YFC0801402)
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