Advancing Oil Shale In-Situ Pyrolysis: Accurate Multiphysics Prediction and Enhanced Extraction Method

Oil shale is an extremely abundant geo-energy resource worldwide, capable of releasing oil and gas through heating above 350°C. In-situ pyrolysis conversion represents a crucial method for the utilization of oil shale resources; efforts are underway to verify its technical feasibility and economic viability at the reservoir scale. However, commercial development has not yet been realized, fundamentally due to an insufficient understanding of the complex multi-field coupling processes underground and the limitations of current in-situ pyrolysis conversion technologies. Through systematic research on the pyrolysis process of oil shale, the secondary cracking characteristics of pyrolysis oil, and rheological properties, we have established a more comprehensive physicochemical model for in-situ pyrolysis conversion of oil shale. This model can accurately predict phenomena observed in laboratory-scale and reservoir-scale experiments of oil shale pyrolysis, providing theoretical support for enhancing reservoir heating and oil-gas recovery. Accordingly, we propose a method of oil shale in-situ reverse pyrolysis by self-generated heat. This approach not only avoids the reservoir clogging issues faced by current technologies but also improves the stability of in-situ reactions and extraction rates. It increases oil recovery by over 10% and enhances energy efficiency by over 60% compared to existing technologies. The research findings provide critical theoretical and technical support for the efficient development of deep oil shale resources worldwide.