Rapid screening and probabilistic estimation of the potential for CO₂-EOR and associated geological CO₂ storage in Colombian petroleum basins

Estimating the oil recovery potential using CO2 (CO2-EOR) at a national level is resource-intensive at a scale that is not usually available. The aim of this study is two-fold: first, the potential for CO2 storage and enhanced oil recovery (EOR) in Colombia is evaluated; and, second, the results from two different calculation methods (stochastic and deterministic) are compared when there is lack of information for a quick screening of suitable oilfields. The deterministic approach is based on expert insight and data found in the literature; while, the stochastic uses statistical data from two different databases (commercial and simulation-based results) to run a Monte Carlo simulation. Potential estimates based on typical values from the literature (deterministic) results in 277 MMbbl (million barrels) of oil and 36 Mt (million tonnes) of CO2. In contrast, a probabilistic-based method using a wide simulation database (stochastic) provides higher values of 690 MMbbl of oil and 203 Mt of CO2. Results using simulation-based and commercial project data also show significant differences. The volume of CO2 injected, which affects the recovery factor, is usually 100% hydrocarbon pore volume (HCPV) in simulation, while commercial projects have nowadays regularly increased from 30% to exceed the 100% threshold. A combination of these approaches avoids a resource-intensive estimation process and effectively provides a more realistic picture of the feasibility of applying CO2-EOR technologies.