论文部分内容阅读
针对顺层瓦斯抽采过程中,因钻孔形变较大、封孔长度不足及封孔方法不合理等因素造成抽采钻孔及其周围煤体漏风严重、抽采瓦斯浓度偏低、流量衰减速度较快及稳定性差等技术难题,基于多孔介质渗流理论、流体平衡理论、“固封液-液封气”钻孔密封技术原理,研究了承压密封液在煤层钻孔内的径向渗流规律,建立了不可压缩流体径向驱气稳定渗流物理模型、密封液径向渗流运动数学方程及相关参数计算公式,进而提出了固液耦合壁式密封顺层瓦斯抽采技术。结果表明,采用固液耦合壁式密封技术可对抽采钻孔及周围煤体裂隙实施动态密封,使得瓦斯抽采过程浓度稳定,单孔平均浓度提高4~5倍,平均抽采瓦斯体积分数达到89%以上,显著提高了本煤层瓦斯的抽采效率。
Aiming at the gas drainage in the successive layers, due to large deformation of the borehole, insufficient length of the sealing hole and unreasonable sealing method, the gas leakage in the borehole and the coal surrounding the drilling hole is serious, the concentration of gas in the gas drainage is low and the flow attenuation Speed and poor stability and other technical problems, based on the theory of porous media seepage, fluid balance theory, “seal liquid - liquid seal gas ” borehole sealing technology, the study of the pressure sealing liquid in the coal seam bore radial The physical model of radial flow control of seepage flow, the physical model of radial flow control of seepage fluid, the mathematical equation of radial flow movement of sealing liquid and the calculation formulas of relevant parameters are established, and the solid-liquid coupled wall sealing gas drainage technology is put forward. The results show that the solid-liquid coupled wall seal technology can dynamically seal the drilled holes and the surrounding coal fractures, and make the concentration of gas drainage stable. The average single-hole concentration is increased by 4 to 5 times. The average gas drainage volume Reaching more than 89%, significantly improving the pumping efficiency of the coal seam gas.