This quarterly report describes progress during the last period in a comprehensive research program on fundamental aspects of carbon dioxide flooding. The research effort is divided into three parts: (1) measurements and analysis of phase behavior and fluid properties of CO/sub 2/-crude oil mixtures, (2) displacement experiments to study mixing of fluids - specifically CO/sub 2/ and crude oil - in reservoir rocks, and (3) development of mobility methods for CO/sub 2/ floods. In the first area, a viscometer based on an oscillating quartz crystal is being developed for installation in a continuous flow apparatus developed previously to study compositions and densities of phases in equilibrium. In the second area, miscible displacement experiments with fluids of matched densities and viscosities in reservoir cores are used to measure effects of rock pore structure and the distribution of oil and water within the pore space on mixing of oil and CO/sub 2/. A one-dimensional simulator is used to predict the performance of gravity stabilized secondary and tertiary CO/sub 2/ floods based on the results of the miscible core floods and independent measurements of phase behavior and fluid properties. CO/sub 2/ floods will then be performed in the same cores to test the accuracy of the predictions. The third area, concerned with mobility control, is itself divided into two parts. The displacement behavior of CO/sub 2/ foams and the synthesis of polymeric materials soluble directly in CO/sub 2/ are being explored as means for thickening CO/sub 2/ to improve reservoir sweep efficiency. 23 references, 26 figures, 8 tables.