Conoco, Inc. conducted a miscible CO/sub 2/ pilot flood in the Shannon Formation of the West Sussex Unit, Johnson County, Wyoming. The unit is located in the western edge of the Powder River Basin and consists of a highly faulted anticlinal structure in which hydrocarbons are trapped. The field has been extensively depleted through primary recovery operations and by a successful waterflood. The purpose of the pilot project was to determine if CO/sub 2/ flooding will recover sufficient quantities of tertiary oil to be economic. Our review indicates that the project was well designed and implemented. The project yielded an oil recovery response. However, questions have been raised as to the relative contributions of Co/sub 2/ and water injection on the oil recovery response. The project is considered to have potential for expansion. However, the prospects are hampered by the lack of a nearby CO/sub 2/ source. This project, as well as others, points out the need to develop CO/sub 2/ resources on a local basis using advanced design processing and available energy resources such as natural gas, coal, and lignite. 2 refs., 10 figs., 4 tabs.