Numerical modeling of in-situ hydrogen production via cyclic air-steam injection in heavy oil reservoirs

Abstract

In the ongoing global pursuit of sustainable energy, in-situ hydrogen production from heavy oil reservoirs has provided a new pathway to generate carbon-zero hydrogen. This study aims to model and evaluate the potential of hydrogen production through cyclic steam-air injection in a heavy oil reservoir. Scenarios using vertical and horizontal wells in a two-dimensional (2-D) model were investigated by numerical simulations, with five injection schedules incorporated. Simulation cases with the combinations of four injection parameters, namely air injection rate, steam injection rate, steam temperature, and oxygen concentration, were generated. Finally, a sensitivity analysis was conducted. The results showed that hydrogen production ranged from 2.4 × 10⁴ to 9 × 10⁴ m³ using vertical wells and from 1.91 × 10⁴ to 1.42 × 10⁵ m³ using horizontals from this 2-D model. The injection schedule with two months of air injection followed by two months of steam injection showed the highest hydrogen production. Increasing steam injection rate promoted hydrogen generation to a certain extent, while increasing the air injection rate, oxygen concentration, or steam temperature resulted in a decline in hydrogen production. This work highlights the importance of control and optimization of the different operation parameters on hydrogen production via cyclic steam-air injection. It lays a strong foundation for the development and implementation of the cyclic steam-air injection technology for carbon-zero in-situ hydrogen production from heavy oil reservoirs.