Abstract

Oil displacement experiments with water driven miscible CO₂ slug flooding were conducted using core flood apparatus. The objectives of the research were to determine the CO₂ slug sizes which correspond to the maximum oil recovery if used for continuous CO₂ displacement processes and to study the effect of CO₂ slug size variation on oil recovery.

The reservoir core model used was a 43 cm length of 5.12 cm diameter cylindrical artificial core with 30% porosity and 1237 mD permeability. The displacement processes were done under a miscible condition for DS-01 oil sample at 2500 psi displacement pressure and 167 °F temperature with 10%, 20%, 30% PV CO₂ slug sizes driven by formation water and finally 100% PV or continuous CO₂ flooding. The displacement was done horizontally at the rate of displacement in porous media of 3.24 cm/hour and injection continued up to 1.2 PV cumulative fluid injected.

Based on the experiment results, we observe that oil recovery at horizontal core displacement for the corresponding CO₂ slug sizes are 75.12%, 82.28%, 84.68% and 87.10% of initial oil in place. The optimum CO₂ slug size for DS-01 oil sample is 32% PV.