A gravity-stable, vertical CO2-miscible-injection flood was implemented in the 824-ft-thick Wellman Unit Wolfcamp reef reservoir in July 1983. CO2 is injected in the crest of the reservoir to displace the oil vertically downward. The producing wells are constantly plugged down out of the ＇＇gassed-out＇＇ interval into the oil bank. This Paper presents the results of the PND(R)-S through-tubing logging tool as a method to determine the CO2/oil/water contacts and the use of multiple-inflatable-packer/sliding-sleeve plugdown assemblies to achieve zonal isolation between gassed-out and producing intervals.