Abstract
Miscible CO2 injection appears to be an important enhanced oil recovery technique for improving sweep efficiency and eliminating CO2-oil interfacial tension resulting in up to 10% higher oil recovery compared to immiscible flooding, in addition to the environmental benefits of reducing greenhouse gas emissions through carbon capturing utilising and storage (CCUS). Moreover, this technique could be similarly applicable to natural gas and nitrogen projects to increase oil recovery and to reduce the associated gas flaring. However, miscible displacement may not be achievable for all reservoirs, in particular, reservoirs with high temperature where high injection pressure would be needed to reach miscibility which likely exceeds the formation fracture pressure. Therefore, to further achieve reservoirs’ potential, there is a pressing need to explore a viable means to decrease the miscibility pressure, and thus expand the application envelop of miscible gas injection in reservoirs with high temperatures.
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