Comparison of enhanced coalbed methane recovery by pure N2 and CO2 injection: Experimental observations and numerical simulation

Enhanced coal bed methane recovery (ECBM) displacement simulation experiments are a direct way to research on the gas displacement process. We carried out two sets of ECBM experiments by injecting pure N2 and CO2 through four large parallel specimens (300 × 50 × 50 mm coal briquette). In the first experiment (N2-ECBM), pure N2 is injected at different pressures to a coal briquette saturated with CH4, in the second experiment (CO2-ECBM), pure CO2...