Most of the evaluations of thermal enhanced oil recovery (EOR) methods in numerical simulations mainly focus on the identification of recovery processes with the greatest potential to increase oil recovery. In some cases, the economic aspects of the EOR methods evaluated are also considered. However, these studies often lack the evaluation of the energy efficiency of the proposed methods as a strategy to support the selection of profitable recovery processes. Therefore, this study aimed to identify the potential of different hybrid cyclic steam stimulation (CSS, with flue gas, foam, nanoparticles, or solvents) methods based on a numerical simulation study using a radial model representative of a large heavy oil reservoir in the Middle Magdalena Basin, Colombia. The simulation results were used to estimate the benefit–cost (B/C) ratios and energy efficiency (EE) indices that can be used to screen and rank the hybrid CSS methods studied. When comparing different hybrid methods, it was found that CSS with nanoparticles or solvents performed better during the first two steam cycles (higher oil saturations). However, CSS with foam and flue gases showed higher incremental oil production (≥3564 bbls or 567 m3) during the sixth steam cycle. Based on an energy cost index (ECI = [(B/C) / EE]), CSS with foam outperformed (ECI ≈ 453) cyclic steam injection with flue gases (ECI ≈ 21) and solvents (ECI ≈ 0.1) evaluated during the sixth steam cycle. The results show that this methodology can be used to guide decision-making to identify hybrid CSS methods that can increase oil recovery in a cost-effective manner and provide an efficient energy balance.

Cyclic Steam Stimulation (CSS), is the most applied thermal enhanced oil recovery (EOR) method worldwide. However, despite the vast experience gained over the last few decades CSS still has its challenges including but not limited to energy efficiency and operational costs. CSS has been evaluated for several years in Colombian heavy oil reservoirs. As CCS approaches its maturity, new alternatives and injection strategies are required to potentially extend the technical-economic limit of this recovery process. This work is focused on the procedure implemented during the design, execution and monitoring of the hybrid technology of steam plus foam as a strategy to improve the performance of a mature CSS process. The strategy developed for experimental tests, numerical simulations and pilot test is described. The evaluation of well head configuration, injection facilities and schedules to assure a good quality and stability of the preformed foam is also discussed. The CSS-foam injection pilot was performed in Teca - Cocorna field. The cumulative surfactant injection was between 3 to 5 tons distributed between two mature wells under CSS at a concentration of approximately 2500 ppm. The facilities used for the foam generation with nitrogen at surface conditions and well injectivity performance will be discussed. Early incremental production due to foam injection has been positive. The first CSS-foam pilot tests allowed the assimilation of lessons learned to incorporate best practices for the continuous improvement in the operation of CSS processes. The performance of CSS-Foam will be updated based on the pilot results due to the level of uncertainties associated with the scaling of laboratory results. According to the performance of the pilot, Ecopetrol will continue evaluating this hybrid CSS technology to improve oil recovery and energy efficiency in fields with steam injection.

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