中文摘要：

为掌握煤层注N2过程中的压力场效应,利用自行搭建的煤层注气实验装置,研究煤层注N2过程中煤层瓦斯压力场随注气压力、注气时间和卸压时间的变化效应及分布规律。结果表明,注气过程中煤层气体压力随注气时间增长迅速升高,并最终趋于平衡,其最高压力小于注气压力。煤层注气过程中,煤层压力场在空间的分布规律为：同一时刻沿注气轴的方向,煤层气体压力逐渐降低,沿垂直于注气轴的方向,煤层气体压力基本相等。注气后卸压过程中,煤层气体压力随时间延长迅速降低,且实验条件下煤层中没有形成高压残留。

英文摘要：

In order to know the pressure field effect in experiment of displacement methane by nitrogen injection in coalbed,the change effect and distribution of gas pressure field in coal seam with pressure gas injection,gas injection time and pressure relief time are studied using the self-built experimental apparatus under nitrogen injection. The results indicate that the coal seam gas pressure is rapidly increased with injection time,and then tends to balance ultimately and the maximum pressure in coalbed is lower than the pressure of gas injection. In the injection process of the experiment,the distribution of seam pressure field in space as follows：the seam gas pressure decreases gradually in the direction of the injection axis and it is equal in the direction which is perpendicular to injection axis. The coal seam gas pressure decreases rapidly with time during the relief process,and there is no high-pressure residual in the coalbed under this experimental condition.