A Massively Parallel Basin Simulation with Multiphase Hydrocarbon Migration of a Large-Scale Model

Abstract We present a multiphase invasion percolation (IP) feature for hydrocarbon migration recently developed for our massively parallel simulator and showcase the results for a large-scale model. The simulator simulates the generation and migration of compositional hydrocarbon fluids from source rocks to predicted present-day reservoirs, providing a valuable tool for understanding hydrocarbon systems with oil and gas separation. The parallel basin simulator supports exploration teams in decision-making by reducing the uncertainty of the new reservoirs with less simulation times. Built upon the framework and data structure of a parallel reservoir simulator, our simulator can manage vast, evolving grids in three-dimensional basin models. Geological deposition spanning millions of years is simulated, including compaction, pressure, temperature calculations, and hydrocarbon generation through petroleum kinetics. An in-house Equation of State (EOS) flash routine is part of the simulator. It computes the phase partitioning of hydrocarbon fluids generated from source rocks. Migration of these multiphase fluids is modeled using a massively parallel invasion percolation method and a backfilling algorithm to predict the evolution of oil and gas reservoirs. Simulation results were verified to ensure consistency with fundamental physical laws and geological principles. We simulated a large geological model ranging stratigraphically from Proterozoic time to the present-day involving 58 different rock types and migration of fluid with four components. A large-scale simulation of about 578 million cells using the multiphase invasion percolation could be completed in 11.32 hours. The model is also simulated at a high grid resolution, comprising over 2.31 billion cells. The results confirm that the multiphase migration is the most computational time-consuming part of the whole-basin simulation. Our contribution lies in developing the multiphase invasion percolation method in a massively parallel basin simulator for simulating the migration of complex hydrocarbon fluids from source rocks to potential reservoirs. This innovation enables rapid and accurate large-scale basin simulations producing multiphase reservoirs, offering significant advantages in terms of speed and reliability for the exploration community.