This report gives detailed descriptions of progress in our research in three major areas of CO/sub 2/ flooding. Topic I concerns mixing and phase behavior of CO/sub 2/ and crude oils at reservoir conditions and methods of predicting pressures required for miscibility. A principal instrument of our experiments is the continuous multiple contact (CMC) apparatus, developed at the PRRC, that speeds acquisition of such data. A weighted parameter correlation formula has been developed to predict minimum miscibility pressure (MMP) from crude oil composition. Topic II examines the process of displacement in reservoir rock, concentrating on those aspects that influence flood efficiency and the extent of the mixing zone. This bears directly on the formation of the ''developed miscibility''or Hutchinson-Braun transition zone in CO/sub 2/ output concentration curve from core floods, with the goal of scaling these results up to the reservoir-size process. In the opposite direction, work at a smaller scale has produced informative video records of displacements in micromodels. Topic III is concerned with mobility control in CO/sub 2/ floods. While the extent of loss of displacement efficiency due to the low viscosity of CO/sub 2/ is variable from field to field, the major goal of research in this area is to develop means for thickening CO/sub 2/ where mobility control is needed. Two methods are being studied. The first is ''CO/sub 2/-foam''- the simultaneous injection of dense CO/sub 2/ and surfactant concentration, CO/sub 2//water volume ratio and rock/brine/surfactant compatibilities. Our second effort is the development of special polymers to dissolve in the CO/sub 2/ and directly increase its viscosity. None are yet available, but significant progress is reported. 121 refs., 79 figs. 20 tabs.