Economics for enhanced coalbed methane (ECBM) and CO₂ sequestration with horizontal wells

Injection of CO₂ into unmineable coal seams is a promising technology for reducing anthropogenic gas emissions and increasing ultimate recovery of coalbed methane. An economic evaluation of an enhanced coalbed methane (ECBM)/CO₂ sequestration project in coalbed with properties similar to those found in the Northern Appalachian basin is presented. PSU-COALCOMP, a two-phase, multi-dimensional, dual porosity compositional coalbed methane reservoir simulator is used. The most important economic parameter to be considered in the design of the project is the net cost of CO₂ (CO₂ cost minus CO₂ credit). A negative net cost of CO₂ in the $0-0.75 range produced positive net present values (NPV) for reservoir permeabilities over 2mD. Lower permeabilities increase production times and costs, having detrimental effects on the economics of the project. Lower injection pressures are favorable for ECMB economics, but the opposite can be true for CO₂ sequestration projects that can benefit from CO₂ credits. The time to start CO₂ injection have negligible influence on the final project economics. The analysis demonstrates the significance of reservoir size, proper design and implementation, and tax incentives for economic viability of projects for ECBM production, and coalseam sequestration. This is an abstract of a paper presented at the SPE Eastern Regional Meeting (Charleston, WV 9/15-17/2004).