Maximizing Hydrogen Yield: Pioneering Gas Injection for Enhanced Light Oil Reservoir Utilization

Abstract

Abstract Sustainable hydrogen production is a key driver for accelerating global energy transition. This study evaluates the influence of injection gas composition on hydrogen yield during in-situ production of light oil reservoirs. In the study, three gas injection strategies: CH4+CO2, CO2+O2, and N2+O2 are investigated with the aid of dynamic reservoir simulation models and advanced reaction kinetics. To conduct the investigation, a three-dimensional compositional reservoir model was built using CMG software and a fluid model consisting of ten light hydrocarbons and two non-hydrocarbon components was incorporated. Results from the analysis reveal that injection gas composed of CH4+CO2 yielded the most hydrogen consistently outperforms alternatives, not only in terms of cumulative hydrogen yield but also by contributing to carbon capture and utilization, aligning seamlessly with global sustainability objectives. This could be because the CH4+CO2 leverages on steam methane reforming and dry reforming of methane during in-situ combustion. Comparing the performance of injection gas composed of CO2+O2 and N2+O2, the study underscores the limitations of combustion-dependent approaches and emphasizes the superior capabilities of reforming processes. CH4+CO2 is effective across a range of temperatures and mole fractions, making it the optimal choice for in-situ hydrogen generation within light oil reservoirs. The efficiency of CO2+O2 is contingent on oxygen availability, and N2+O2, while comparable, lacks the enhancement of methane in promoting hydrogen generation. Ranking the performance of the three gas injection strategies investigated in this study, CH4+CO2 yielded the most cumulative hydrogen yield and hydrogen-to-syngas ratio, this was followed by N2+O2 and CO2+O2. These findings offer pivotal insights for refining operational parameters and advancing sustainable applications in enhanced hydrogen production within light oil reservoirs. This research contributes not only to the ongoing discourse on sustainable energy solutions but also addresses efficiency goals and environmental concerns linked to greenhouse gas emissions. The practical implications extend to the energy industry, providing a pathway for sustainable hydrogen production within the intricate landscape of light oil reservoirs.