Physical and Numerical Simulations of Heavy Oil Recovery Through Supercritical Water Flooding

Supercritical water (SCW) has emerged as a promising thermal agent for enhancing heavy oil recovery, yet its recovery mechanisms have not been fully understood, thereby limiting its practical application. To address this knowledge gap, this study conducted pyrolysis and sand pack flooding experiments to study the feasibility and mechanisms of SCW flooding. Subsequently, a novel simulation model dedicated to SCW flooding was developed and its accuracy was validated through fitting the experimental results. Furthermore, sensitivity studies were performed using the developed model to explore the impact of various factors on SCW flooding. The findings revealed that in SCW, the heavy oil upgrading was found to effectively reduce oil viscosity, thereby playing a pivotal role in enhancing oil recovery. Compared to steam flooding, SCW flooding led to a remarkable 14% increase in oil recovery, demonstrating its technical viability for deep heavy oil recovery. The developed numerical model, incorporating experimental data and history matching techniques, demonstrated a high level of accuracy in simulating SCW flooding. The simulation outcomes highlighted that SCW flooding induced heavy oil upgrading, consequently improving oil mobility. Additionally, it was observed that higher SCW pressures and temperatures positively impacted its production performance. However, it is important to note that excessive temperature elevation could result in significant coke deposition, potentially causing damage to the reservoir formation.