采用气-液-固三相驱替模拟系统.开展了煤样封堵及反向注水.气驱替煤粉解堵煤样的系列室内实验.探讨了不同封堵压力及解堵介质.压力下煤样渗透率的变化特征.结果表明:煤样封堵过程中液相渗透率随时间呈对数衰减规律,达到平衡时间随着封堵压力的提高呈现衰减的趋势,煤粉颗粒沉积在渗流入口端堵塞煤样的孔裂隙通道.是引起煤样渗透率下降的主要原因,当解堵介质为水:反向注水压力等于封堵压力时煤样最终液相渗透率低于封堵前的数值.反向注水压力大于封堵压力时煤样液相渗透率会在一定的时间段内有小幅度提高.而且反向注水压力越大.液相渗透率上升的反应速度越快.煤样的最终液相渗透率与封堵完成后相当,当解堵介质为气:反向注气压力大于或等于封堵压力时能够完全解堵污染煤样:煤样的气相渗透率变化曲线为类[S"型曲线且全过程气相渗流经历了线性增长阶段.指数增长阶段.稳定阶段,少量小粒径低密度悬浮煤粉颗粒产出促进了渗透率的缓慢提高,密度相对较大的下沉颗粒产出是煤样快速完成解堵的主要原因,反向注气压力越高.解堵速度越快且反向注气压力越接近封堵压力解堵速度对压力变化的敏感性越高,反向注气解堵污染煤样的能力强于反向注水.水.气体分子性质的不同及驱替速率的差异是反向注水.气结果差异性的主要原因.

Using the gas-liquid-solid three-phase displacement simulation system,a series of laboratory experiments on coal sample plugging and coal blockage removal driven by reverse water and gas injection the was carried out,the variation characteristics of coal sample permeability under different blockage pressures and blockage removal medium.pressures were discussed.The results show that the permeability of liquid phase decreases logarithmically with time in the process of coal sample blockage.The time to reach equilibrium tends to decrease with the increase of plugging pressure.The deposition of pulverized coal particles at the inlet of seepage blocks the pore and fracture channels of coal samples,which is the main reason for the decrease of permeability of coal samples.When the unplugging medium is water,the reverse water injection pressure is equal to the blockage pressure,the final liquid permeability of the coal sample is lower than that before the plugging. The reverse water injection pressure is greater than the plugging pressure,the liquid permeability will increase slightly in a certain period of time. Moreover,the higher the reverse water injection pressure is,the faster the reaction speed of the liquid permeability rises,and the final liquid permeability of the coal sample is equivalent to the value after the completion of plugging.When the unplugging medium is gas. The reverse gas injection pressure is greater than or equal to the plugging pressure,it can completely remove the blockages in coal sample.The variation curve of gas permeability of coal sample is similar to [S" curve,and the gas permeability in the whole process has experienced linear growth stage,exponential growth stage and stable stage.The output of a few small particle size and low density suspended pulverized coal particles promote the slow increase of gas permeability.The output of subsidence particles with relatively large density is the main reason for the coal sample completely removing the blockages quickly.The higher reverse gas injection pressure,the faster blockage removal speed and the closer the reverse gas injection pressure is to the plugging pressure,the more sensitive the plugging velocity is to the pressure change.The blockage removal ability of reverse gas injection is better than that of reverse water injection.The difference of water and gas molecular properties and drive rate is the main reason for the difference of reverse water and gas injection results.

1 试验

   1.1 试验设备

   1.2 试验样品

   1.3 试验方法及步骤

2 实验结果与分析

   2.1 不同封堵压力下煤样渗流特征

   2.2 反向注水.气解堵煤样渗流特性

3 讨论

4 结论