Innovative In-Situ Combustion Technique: Dynamic Interval Air Injection for Enhanced Oil Recovery

Abstract

Enhanced oil recovery (EOR) methods are crucial for tapping into difficult-to-produce heavy oil deposits. Among these, in-situ combustion (ISC) has demonstrated potential economic and environmental advantages over energy-intensive thermal techniques, such as steam-assisted gravity drainage. A promising variant of ISC, known as toe-to-heel air injection (THAI), offers the potential for greater efficiency and more sustained results compared with conventional ISC. Although pilot attempts in Canada have faced challenges, THAI remains an underexplored method that, with further refinement and research, could unlock new opportunities in thermal recovery. With this paper, we propose an innovative advancement in the THAI process, introducing dynamic interval air injection (DIAI), a technology that leverages dynamic air injection intervals. The approach optimizes the progression of the combustion front, significantly improving overall recovery efficiency within the THAI framework. Using kinetic upscaling, we validated laboratory- and field-scale models against data from the literature. The verified model was then used to investigate the performance of the DIAI configuration featuring a single horizontal injector/producer wellbore with dynamically shifting air injection intervals. The results demonstrated a 2.6-fold increase in oil displacement and a 15% reduction in cumulative oxygen production/breakthrough compared with the state-of-the-art THAI configuration. While complete combustion front advancement was not fully observed, the heat generated effectively mobilized oil toward the producer, indicating technical promise. These findings highlight the potential of dynamic air injection to enhance oil recovery and suggest further studies to optimize timing intervals for maximum efficiency.