注气驱替提高煤层气采收率实验研究

    Experimental Study on Improving Coalbed Methane Recovery by Gas Injection

    • 摘要: 通过进行单一组分N2、CO2以及不同比例混合气驱替的对比实验,探究不同气体、不同比例条件下的煤层气驱替规律。研究结果表明,N2随驱替压力升高,驱替效率先增后减,置换效率越来越差,驱替渗透率越来越低,但仍高于原始煤岩渗透率;CO2随驱替压力升高, 驱替效率一直增加,置换效率变化不大,驱替渗透率先降后升,整体低于原始渗透率;混合气(CO2∶N2=1∶4)和混合气(CO2∶N2=1∶9)驱替规律接近于N2,混合气(CO2∶N2=1∶1)驱替规律接近于CO2;N2恒压驱替优于间歇驱替,CO2间歇驱替优于恒压驱替。

       

      Abstract: Through the contrast experiments of single component N2, CO2 and different ratio of mixture flooding, the displacement laws of coalbed methane under different gas and different proportion are explored. The results show that, with the increase of N2 displacement pressure, the displacement efficiency increases first and then decreases, the replacing efficiency gets worse, the coal permeability gets lower and lower, but still higher than the original permeability; with the increase of CO2 displacement pressure, the displacement efficiency increases all the time, the replacing efficiency changes little, the permeability decreases first and then increases, the whole permeability is lower than the original permeability; the laws of mixture (CO2∶N2=1∶4) and mixture (CO2∶N2=1∶9) are similar to N2, and the law of mixture (CO2∶N2=1∶1) is similar to CO2. N2 constant displacement is better than intermittent displacement; CO2 intermittent displacement is better than constant displacement.

       

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