Colombia is evaluating different steam-based hybrid oil recovery technologies as a strategy to face current challenges in the development of heavy oil reservoirs. Oil price volatility, the need for an energy transition, and carbon footprint reduction are factors limiting the commercial deployment of conventional steam injection projects. Ecopetrol evaluates the hybrid steam methods at laboratory scale as one of the different options to overcome current constraints developing heavy oil resources. The ongoing experimental program is supported by numerical modeling as a prior step to upscale the results at the pilot-scale.
This study aims to present history match results and describe the numerical modeling approach of hybrid steam experiments (50 mm diameter × 1.1 m long assembly) and compare it against the baseline steam injection simulation. The first hybrid test involved the injection of steam and flue gas considering consecutive floods that included a saturated steam flood (SSF), a flue gas slug injection, and a second saturated steam flood. The second test was a steam and solvent injection following the same experimental protocol (SSF + solvent + SSF).
The variables matched included produced fluids, pressures, produced gas compositions, and temperature profiles. One important feature is that all three models use the same set of water-oil relative permeability curves obtained from an independent experiment. Also, it was assumed those curves are not a function of temperature, which simplifies the modeling and allows focusing on the physical mechanisms relevant to each experiment. For instance, for the hybrid steam-flue gas test, it was necessary to include an additional set of gas-oil relative permeability curves to account for the presence of the flue gas in the gas phase. The hybrid steam-solvent test was focused on modeling the mixing of the native oil with the injected solvent. The proposed workflow led to a good history match of all variables, particularly total produced fluids, temperature profiles, and injection pressures. Additional recommendations are provided based on laboratory observations to understand important mechanisms such as trapped gas, relative permeability hysteresis, and solvent characteristics.
A new methodology to simulate hybrid steam methods is provided. The proposed numerical approach incorporates novel energy efficiency and carbon intensity indexes to guide the decision-making and identify recovery strategies driven by its efficiency and reduce carbon footprint. Both hybrid tests led to energy efficiency improvements and reduction in carbon intensity up to 20%. These indexes combined with experimental results will be key input parameters for designing and commissioning future pilot tests using numerical simulations at the field scale.