关键词: 混合气体驱替煤层气, 低渗透, 不可采煤层, 煤层气采收率, 单产量, 可行性

Abstract:

Gas enhanced coalbed methane recovery technology (ECBM), which has the win-win effects on reducing the greenhouse gas emissions and improving coalbed methane recovery ratio, is an emerging technology in recent years. Related research of ECBM has been paid the extensive attentions by major developed countries. Because of the pressure from greenhouse gas emissions reduction, up to now, the developed countries are focusing on studying the application of CO2-ECBM technology in high permeability and unminable coal, for the purpose of permanently storing CO2 as more as possible and enhancing CBM recovery ratio at the same time. Currently, research of this aspect is started just now in China. Most coal in China has the characteristics of low permeability and it is difficult to define unminable coal or minable coal, so it is questionable to apply CO2-ECBM in these coalbed. In view of the characteristics of coal and the present situation of coal mine gas drainage in China, the gas mixture enhanced coalbed methane (G-ECBM) technology has been suggested for the purpose of enhancing coalbed methane recovery ratio. The feasibility of G-ECBM in China has been analyzed by theoretical analysis, numerical simulation and field test study. The results show that G-ECBM technology is applicable to the low permeability and minable coal in China; and it can enhance the coalbed methane recovery ratio and single well production.

Key words: gas mixture enhanced coalbed methane recovery (G-ECBM), low permeability, unminable coal, coalbed methane recovery ratio, single well production, feasibility