The economic feasibility of enhanced coalbed methane recovery using CO2 sequestration in the San Juan Basin

摘要

Carbon dioxide emissions are considered a major source of increased atmospheric CO2levels leading towards global warming. CO2 sequestration in coal bed reservoirs is onetechnique that can reduce the concentration of CO2 in the air. In addition, due to thechemical and physical properties of carbon dioxide, CO2 sequestration is a potentialoption for substantially enhancing coal bed methane recovery (ECBM).The San Juan Fruitland coal has the most prolific coal seams in the United States. Thisbasin was studied to investigate the potential of CO2 sequestration and ECBM. Primaryrecovery of methane is controversial ranging between 20-60% based on reservoirproperties in coal bed reservoirs15. Using CO2 sequestration as a secondary recoverytechnique can enhance coal bed methane recovery up to 30%.Within the San Juan Basin, permeability ranges from 1 md to 100 md. The Fairwayregion is characterized with higher ranges of permeability and lower pressures. On thewestern outskirts of the basin, there is a transition zone characterized with lower rangesof permeability and higher pressures. Since the permeability is lower in the transition zone, it is uncertain whether this area is suitable for CO2 sequestration and if it candeliver enhanced coal bed methane recovery.The purpose of this research is to determine the economic feasibility of sequestering CO2to enhance coal bed methane production in the transition zone of the San Juan BasinFruitland coal seams. The goal of this research is two- fold. First, to determine whetherthere is a potential to enhance coal bed methane recovery by using CO2 injection in thetransition zone of the San Juan Basin. The second goal is to identify the optimal designstrategy and utilize a sensitivity analysis to determine whether CO2 sequestration/ECBMis economically feasible.Based on the results of my research, I found an optimal design strategy for four 160-acre spacing wells. With a high rate injection of CO2 for 10 years, the percentage ofrecovery can increase by 30% for methane production and it stores 10.5 BCF of CO2. Theeconomic value of this project is $17.56 M and $19.07 M if carbon credits were grantedat a price of $5.00/ton. If CO2 was not injected, the project would only give $15.55 M.