Reservoir Performance of a Gravity-Stable, Vertical CO2 Miscible Flood: Wolfcamp Reef Reservoir, Wellman Unit

A gravity-stable, vertical CO[sub 2] miscible flood was implemented in the Wellman Unit Wolfcamp reef reservoir in 1983. CO[sub 2] was injected into the crest of the reservoir to displace the oil vertically downward, and water was injected into the lower water-swept region of the reservoir to maintain reservoir pressure at slightly above the minimum miscibility pressure (MMP). Excellent production response to increased CO[sub 2] injection was observed. The reservoir performance was encouraging and indicated excellent volumetric conformance and ultimate recovery. This paper reviews the operating strategy and project performance from inception through mid-1991.