Economic Evaluation of Nitrogen Injection for Coalseam Gas Recovery

Abstract

Abstract This paper presents a scoping study to investigate the economic viability of nitrogen injection to improve the recovery of coalbed gas. The sensitivity of the analysis to key reservoir parameters is also presented. The results of the study suggest that nitrogen injection may be more attractive than conventional pressure depletion for lower permeability formations where the loss in permeability with pressure decline is significant. Nitrogen injection economics are shown to be very sensitive to the costs associated with injection and separation and are adversely affected by reservoir heterogeneity.