Impact of physical phenomena and cyclical reinjection in miscible CO2-WAG recovery in carbonate reservoirs

Abstract

Abstract Carbonated reservoirs with high percentage of CO2 have been discovered and produced in the Brazilian pre-salt cluster. Recovery techniques, such as CO2-WAG, have hence been evaluated and applied, as in the Lula field. Although studies demonstrate the advantages of this technique, it is still difficult to estimate an increase in oil recovery. Thus, this work presents a methodology to evaluate the impacts of the main phenomena that occur and how CO2 recycling can benefit the management of these fields. The results showed an increase in recovery with the modeling of the main phenomena such as relative permeability hysteresis and aqueous solubility of CO2, accompanied by a significant increase in CO2 injection. However, the recycling of the CO2 produced was shown to be fundamental in the reduction in this injection and to increase the NPV. The results showed a 4% increase in oil production and 9% in NPV, considering a producer–injector pair.

Keywords

• CO2-WAG
• Relative permeability hysteresis
• Aqueous solubility
• Cyclical reinjection