The exploration and development of deeper wells with heavier and more viscous oils, requiring greater operating pressures and more fracture to fissures to release the oils. This results in significantly increased sand content that has the potential to bring about a fundamental shift in flow behaviour. This project aims to investigate the potential – and develop – a coupled smooth particle hydrodynamics (SPH) and discrete element method (DEM) model to simulate high-pressure multi-phase flows with support from an extensive experimental programme and industrial collaboration.