Chemical enhanced oil recovery simulation in highly stratified heterogeneous reservoir : a field case study

Oil and gas companies are looking for proven hydrocarbon reserves from their existent drained reservoirs with the objective to extend the production and economical life of their fields. The chemical enhanced oil recovery (CEOR) has raised with a myriad type of process that goes beyond the primary and secondary recovery. The polymer flooding (PF) is a widely applied process in reservoirs with low swept efficiency after the water flooding (WF) process. Colombian field has one of the first polymer pilots in the region with positive results of oil recovery in “A” sands. Thus, the operator is interested in the expansion of PF for the same reservoir and even in deeper reservoir sands. This thesis focuses in the evaluation of different scenarios of PF and surfactant polymer flooding (SPF) for the producer layers A and B with a mechanistic model, thus obtaining new recommendations for the recovery strategy in the field. Therefore, a sector model was constructed from a full field commercial simulator to the in-house simulator: UTCHEMRS. In addition, this sector model was migrated to a second commercial simulator allowing a performance comparison for three simulators. UTCHEMRS model was validated with the commercial simulators through the history matching (HM) phase. The primary and waterflood history match was in agreement with the field data. Simulation results suggested that PF for the base case in “A” sands presented an incremental oil recovery of up to 12% additional to water flooding. Additionally, PF was extended to the lower layer “B” sand to investigate the potential of polymer injection. The PF injection in both reservoirs simultaneously loses swept efficiency and decreases the oil recovery in 3%. However, a hypothetical case of new infill producer wells with the objective of testing the individual reservoir performance has revealed that PF is having important raises in oil recovery for B sands as well. Though, further research should be developed in order to strengthen this interpretation. Finally, the results of SPF case for A sands are inconclusive because a laboratory tests of surfactant phase behavior is needed to ensure the lowest IFT in reservoir conditions