Investigation CO2 EOR Types with Constrained CO2 Volume and Impurities for a High-Quality Sandstone, Stratified Offshore Newfoundland Reservoir

Abstract

AbstractThe objective of this study is to evaluate the potential of CO2 sequestration coupled with oil recovery to lower the carbon intensity of incremental oil recovered considering different CO2 EOR types. A compositional stratified reservoir model (with/without crossflow) is used to investigate the effect of limited CO2 volume on the performance of CO2-WAG, enriched CO2-WAG, and carbonated water injection (CWI). We show that joint optimization of oil recovery and carbon storage can decrease carbon intensity. CO2 flooding, CO2-WAG, enriched CO2-WAG, and CWI are investigated under constrained CO2 volumes on a percentage pore volume basis. A sensitivity analysis using Response Surface Methodology (RSM) is carried out within a range of reservoir temperature (50-130°C) and pressure (20-70 MPa) conditions. CO2 volumes that can be captured from offshore power generation are likely insufficient for CO2 flooding but could work for CWI, CO2 WAG or enriched CO2 WAG (CH4-CO2 WAG). Highest incremental oil was found using CWI. However, it did not consider carbon pricing nor look to minimize oil production emissions intensity. Emissions intensity is the new metric during our transition to cleaner energy. CWI can store less than 20% amount of CO2 captured while CO2-WAG, enriched CO2-WAG with 7-10% lower oil recovery, however, can store much larger quantities. The stratified reservoir with crossflow cases had higher recovery factors and later water breakthrough than without crossflow cases. The use of WAG reduced the extent of crossflow and the high WAG ratio (3:1) would lead to a higher oil recovery (additional 3% for enriched CO2 WAG case). Recovery factor increased with decreased temperature and increased pressure, since CO2 is in its supercritical state in the range studied. Proxy models showed good performance with high determination coefficients (R2), between 0.93 - 0.99. EOR studies focus on incremental oil recovery (without carbon pricing). CCUS studies maximize CO2 storage (assuming infinite CO2). We investigate the value of capturing post combustion CO2 from offshore power generation considering constrained CO2 volumes and different EOR methods without reproducing CO2. This study investigates the joint optimization of oil recovery and carbon storage bringing a unique perspective and way to decrease carbon intensity during the oil transition era.