Mobility ratio, relative permeability and sweep efficiency of supercritical CO2 and methane injection to enhance natural gas and condensate recovery: Coreflooding experimentation

Enhanced natural gas and condensate recovery has more recently stimulated an immense popular interest in oil exploration and production. While numerous laboratory and computational studies of carbon dioxide (CO2) injection into conventional oil reservoirs have been reported in the open literature, scarce work is being disclosed on CO2 displacement characteristics with both natural gas and liquid condensate where the displacement mechanisms are well-known to be significantly different to those in conventional gas/oil systems.This paper quantitatively investigates the recovery efficiency, pattern behavior and relative permeability of: (1) condensate following supercritical carbon dioxide (SCCO2) injection, methane injection and the injection of their mixtures; and (2) natural gas of various compositions following pure SCCO2 injection. This investigation includes two sets of coreflooding experiments: the first is to observe the microscale displacement efficiency and stability of natural gas following pure SCCO2 injection while the second was conducted to study the percentage of condensate recovery following the injection of different SCCO2-methane concentrations. This work is part of an integrated enhanced natural gas and condensate recovery project conducted for a local reservoir in Western Australia. This data will help the operators develop operational and design strategies for their current and future EOR projects, as well as provide parameters for full-field simulation practices.

► Supercritical CO2 (SCCO2) injection offers better condensate sweep efficiency and thus more recovery over the injection of methane.
► SCCO2 injection improves condensate relative permeability as it provides favorable mobility conditions and stable displacement front.
► Application of this technology requires consideration of injection rate, heterogeneity, Kv/Kh ratio, well layout and stratification.