氮气在水饱和岩心中的渗流规律

用带有刻度的气液分离装置研究了氮气在不同含水饱和度岩心中的流动特性及突破规律。实验结果表明,当气体注入压力一定时,液体流出量缓慢增加,气体突破之前伴随液量的突然增大;在所研究的时间范围内,各阶段气体平均流速呈幂指数增加。随着注入压力的增加,气体在岩心中的突破时间变短,排出液量增大,表明气体在岩心中的流动速度增加,波及体积增加,且各阶段的流速仍呈幂指数变化,这说明气体的流动特性随其侵入量的变化而变化。随着压力的增加,岩心气体视渗透率先快速增加,然后趋于平缓,这是压缩引起的气体滑脱效应减弱所致;而完全饱和水的岩心随着残余水饱和度的降低,气体视渗透率先缓慢增加,当含水饱和度降到一临界值时,视渗透率迅速增大,这是空间增大引起气体的滑脱效应增加所致。

Nitrogen percolation behavior in water saturated core

The flow behavior of nitrogen in cores with different water saturation levels was studied using a graduated gas-liquid separator to simultaneously measure the gas and water flow rate from the cores.The experimental results indicate that under the constant nitrogen injection pressure,the effluent water increases slowly at the beginning of the nitrogen injection process,then increases sharply before the gas-breakthrough.The average nitrogen effluent velocity increases exponentially with time in the studied ti...