A joint DOE-Gulf Oil Corporation, nonproducing carbon dioxide minitest was conducted in the Little Knife Field in western North Dakota. At the time of the project, the reservoir was undergoing primary depletion and had no secondary recovery operations underway. The five-acre inverted four-spot tested the applicability of a CO/sub 2/-alternating-with-water injection process to commercially displace oil in the nonflooded Mission Canyon Formation located in the Williston Basin. The nonproducing test was evaluated using time-lapse logging and fluid sampling to monitor fluid movement as injected CO/sub 2/ and water displaced 41/sup 0/ API oil in three observation wells which surrounded a central injector. Numerical simulation studies using the time-lapse logging data provided the basis for estimating pilot performance and evaluating a proposed expansion of the process to a 160-acre pattern. Gulf personnel are to be commended for designing and implementing a state-of-the-art, nonproducing pilot test of the CO/sub 2/ process. Results obtained in the pilot show an optimistic incremental recovery over waterflooding of 8.0 percent of the oil-in-place (OOIP) with an optimistic 1.0 STB of oil production estimated per 5.0 to 8.0 MSCF of injected CO/sub 2/ depending on exclusion or inclusion of Zone W. Assuming a more realistic 1.0 STB of oil recovered per 10.0 MSCF of injected CO/sub 2/, these results still encourage the commercial application of the process to the Little Knife Field upon location of a suitable CO/sub 2/ source. 34 refs., 17 figs., 13 tabs.