Decarbonizing Onshore Oil and Gas Operation for EOR Using Aspen HYSYS and CMG-STARS Simulators

Abstract

The global pursuit of decarbonization and net-zero emissions by 2050 has positioned carbon capture, utilization, and storage (CCUS) as a critical pathway for climate mitigation. Among its approaches, CO₂-enhanced oil recovery (CO₂-EOR) offers the dual benefit of reducing atmospheric emissions while improving recovery from mature reservoirs. This research develops an integrated modeling framework that combines Aspen HYSYS surface process simulation for CO₂ capture and conditioning with CMG STARS reservoir simulation for injection performance. A postcombustion capture system using 30 wt% monoethanolamine (MEA) was modeled In the Aspen HYSYS V14.4 with absorbers, strippers, and dehydrators configured to produce pipeline-grade CO₂. Sensitivity analysis was performed on tray numbers in the absorbers, strippers, and dehydrators showing their effect on the final CO₂ purity of (≈99.67%) at 5 bar and 37 °C, confirming technical feasibility for injection. The conditioned CO₂ of (≈99.67%) purity was injected into a synthetic reservoir at 1.0 MMSCFD, for 5000days simulation period in the CMG STARS reservoir simulator, resulting cumulative oil recovery of 931,936 bbl and a recovery factor of 31.12%. Over the simulation period about 5 MMMSCF (of ~570,000 tonnes) of CO₂ was captured and sequestered avoiding equivalent atmospheric CO₂ concentration increase of ~7.3 × 10⁻⁵ ppmv and ~8.0 × 10⁻⁷ °C equilibrium global warming temperature increase. These results highlight the dual role of CO₂-EOR as both a decarbonization strategy and a production-enhancing technique.