Keywords: carbon dioxide, CO2, carbon sequestration, phase behaviour, simulation, enhanced liquid recovery, gas condensate reservoirs, hydrocarbons
Enhanced liquid recovery by carbon dioxide sequestration in gas/condensate reservoirs
CO2 sequestration in a depleted gas/condensate reservoir could be a viable option due to the economic benefits associated with the enhanced liquid recovery. According to previous laboratory investigations, CO2 may be superior to methane (CH4) or nitrogen (N2) for enhanced condensate recovery from the depleted gas/condensate reservoirs. However, the impact of CO2 distribution (and the associated mixing with the reservoir fluid) on liquid recovery from the gas/condensate has not yet been investigated. In this study, a compositional reservoir simulation was used to investigate the impact of the reservoir characteristics on the CO2 distribution and the interactions with the hydrocarbons in gas/condensate reservoirs. The results indicate that CO2 sequestration is able to significantly improve the liquid recovery even when severe heterogeneities are present. The liquid recovery not only results in economic benefits but also provides additional pore space for CO2 storage. [Received: March 26, 2012; Accepted: August 14, 2012].