A new modelling approach for in-situ hydrogen production from heavy oil reservoirs: Sensitivity analysis and process mechanisms

The increasing demand for eco-friendly and renewable energy has positioned hydrogen as a viable solution for global energy and environmental challenges. In-situ combustion gasification of heavy oil reservoirs offers potential for large-scale hydrogen production, injecting steam and air (or alternative gases) to trigger complex chemical reactions leading to hydrogen and syngas generation. However, a research gap exists due to the lack of a comprehensive numerical model for accurately simulating hydrogen production under SARA-based (saturate, aromatic, resin, asphaltene) hydrocarbon characterization in experiments and field study. This study addresses the gap by investigating in-situ combustion gasification for hydrogen generation in heavy oil reservoirs. A novel model based on SARA characterization is proposed, showing fidelity with experimental and numerical results. Different injection strategies, like pure oxygen and CO2, impact hydrogen production. Oxygen injection yields less hydrogen than air injection, highlighting the importance of oxygen control. CO2 injection reduces hydrogen but aids carbon management. The oxygen to nitrogen ratio (61/39) demonstrates the highest hydrogen-to-syngas ratio. Practical implementation requires economic feasibility, operational practicality, safety, and environmental considerations. This study advances in-situ combustion gasification technology, facilitating efficient and sustainable hydrogen generation from heavy oil reservoirs.