Reservoir-Topside Integrated Assessment of Dedicated CO2-Rich Gas Injection in a Brazilian Pre-Salt Benchmark: Displacement Mechanisms and Field Performance
Resumo
Managing CO2 in offshore oil production is critical for both environmental and operational objectives, particularly in Brazilian pre-salt reservoirs where high CO2 content coexists with significant natural gas volumes. Reinjection strategies are widely employed to maintain reservoir pressure, enhance oil recovery, and minimize flaring. In this work, an integrated reservoirtopside modeling framework is proposed to realistically evaluate CO2 injection strategies, accounting for fuel gas, gas export, and reinjection flows. This study evaluates the effects of a dedicated well for CO2-rich gas injection compared with conventional reinjection of natural gas mixed with CO2 spread among all injectors. Two complementary case studies were conducted: (i) a simplified injector-producer pair to isolate fundamental displacement and thermodynamic mechanisms, and (ii) a field-level strategy with ten producers and ten injectors to assess the impact of dedicated CO2 injection on production and economic performance under three geostatistical scenarios. Results from the simplified strategy demonstrate that CO2-rich injection improves microscopic displacement through oil swelling and interfacial tension reduction, while modifying pressure profiles and sweep behavior. In the developed strategy, dedicated CO2 injection strongly depends on injector location, geological heterogeneity, and injector-producer connectivity. Overall, the results highlight dedicated CO2-rich injection as a promising parameter for optimizing production strategy, with potential for improving oil recovery, and enhancing field management. The study demonstrates that strategic allocation of CO2 injectors can significantly influence displacement efficiency, sweep behavior, and economic performance in heterogeneous offshore reservoirs.
Autores
Davi Éber Sanches de Menezes, Vinicius Eduardo Botechia, Denis José Schiozer
