Analysis of Heavy-Oil Immiscible CO2 Tertiary Coreflood Data

Abstract

Summary This paper describes the results of a series of tertiary, immiscible, CO2 corefloods of Wilmington field Pliocene reservoir rock containing heavy oil (±14°API [+0.97 g/cm3] and±480 cp [+480 mPa-s]). An initial set of corefloods defined the recovery potential of the CO2 injection, while a series of later tests served to define the process more accurately as applied in the field. In an attempt to understand the displacement mechanism, simulator matching of one of the later, more refined groups of corefloods was performed. The corefloods and simulator work indicate that the incremental recovery is more than can be accounted for by oil-viscosity reduction and crude-oil swelling. The improved performance is attributed to more favorable displacement characteristics and the presence of a free gas saturation in the cores.