Reservoir-condition phase-behavior and tertiary-gasflood studies have been conducted in the laboratory to investigate the effect of hydrocarbon-injectant composition and pressure on oil-displacement efficiency. Lower oil;recovery efficiencies and lower injectant mobilities have been observed at lower enrichment levels and/or at lower pressures. Coreflood oil recoveries, however, remained high for gas injectants that are below multiple-contact miscible (MCM) with the oil. These results suggest that near-miscible hydrocarbon-gas-injection processes show promise and that there may be a trade-off between local oil-displacement efficiency and gas-sweep efficiency in near-miscible displacements in the field.