The goal of this project has been to develop methods to counteract the harmful influence of the naturally unfavorable mobility ratio in CO/sub 2/ floods. Our efforts have been directed towards the development of two distinct methods for increasing the effective viscosity of dense CO/sub 2/. One of these involves the use of water-CO/sub 2/ emulsions or foams as the displacement fluid. The second type of mobility control additives being investigated are direct thickeners - solutions of certain polymers in the CO/sub 2/. Significant progress has been made in both these areas of development. In conjunction with the development of means of thickening the CO/sub 2/ displacement fluid, the need also exists to assess the behavior and effectiveness of the additives. The assessment is to be performed in a standardized, repeatable core-flooding test which has been developed as a third part of the project's laboratory work. As with the development of the thickeners themselves, good progress has also been made here, and the experimental and measuring system has been brought to operating condition.