Laboratory measurements of CO2 and brine injectivities in restored San Andres carbonate cores at reservoir conditions are reported. Included are results both with unsaturated CO2 and brine as well as with brine equilibrated with CO2 and CO2 equilibrated with brine. A waterflood, oilflood, and miscible flood followed by many cycles of CO2 and brine injection were done. Important results are the following: endpoint CO2 relative permeabilities were substantially smaller than both water and oil endpoint relative permeabilities making CO2 less mobile than would be anticipated just from viscosity ratios, the irreducible water saturation increased after an oilflood and persisted during subsequent CO2 floods, residual CO2 saturations to saturated brine were about the same magnitude as the residual oil saturations to waterflood, and the injectivity of unsaturated brine was much higher than saturated brine because of absorption of the CO2 phase.

The laboratory work was done in support of an injectivity field trial. The results of an injection of two cycles of CO2 and of brine into a well in the Mabee Field in the San Andres formation are reported. Both the CO2 and the brine field injectivities were significantly greater than the pre-CO2 waterflood injectivity on a volumetric basis. Field injectivities were somewhat greater than would be anticipated from the laboratory data. A simple analytical injectivity model could approximate some of the features of the field test but was not completely satisfactory.

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