Predictive modelling of run-out distance and sedimentation rate of channel-basin turbidity currents with a new numerical approach

Density currents are caused by the difference of potential energy among fluids of distinct densities. Turbidity currents correspond to a specific type of density current where there is a considerable concentration of suspended particles that are transported by the flow. This phenomenon is often seen as one of the main factors responsible for the generation of sedimentary deposits that form hydrocarbon reservoirs. Numerical modelling is one of the most used approaches to model this process, based on solving a set of partial differential equations employing numerical methods. This paper presents the main hydrodynamic and depositional characteristics of turbidity currents formed in an unbounded configuration. The SuLi code, used in the present work, solves the incompressible continuity and Navier-Stokes equations using the projection method and the Large Eddy Simulation methodology. A finite difference scheme was implemented in order to solve the linear advection-diffusion equation. The code verification was carried out based on results present in the literature, demonstrating that the implemented numerical schemes are adequate to satisfactorily reproduce the dynamics of turbidity currents. Significant results were obtained considering different particle sizes, allowing the development of a comprehensive methodology for estimating the run-out distance of the deposit and the sedimentation rate over time as a function of the characteristic diameter of the grain.