MassFLOW-3D Simulation of Sediment Flow Distribution and Deposition of Sand in the Nini Field, Ty Reservoir

The present study is aimed to evaluate, with the aid of the CFD software MassFLOW3DTM, the sediment flow behavior and distributionof sand in the Nini Ty reservoir (part of the Siri Fairway area). The Siri Fairway, located east of the Central Graben, shows a steep slope on the southwestern direction. Major interest is to evaluate the possibility of the sediments to create some depo-structures before plunging in the deeper part of the graben.

Particular attention is given to the behavior of flows around a salt diapir, located in the south western part of the field.

Computational fluid dynamics (CFD) is a tool for numerical solution of the physical equations describing fluid flow and sediment transport.

The method has been widely applied in the engineering branches of fluid mechanics, but has been little used in sedimentological research. Nowadays CFD is being developed to fill the gap between small and large scale, integrating data from theory, nature, and experiments. It can also shed light on flow parameters which are so far impossible to deduce from experimental and field studies. Novel CFD software MassFLOW-3D™, has been developed and successfully used to construct a process-based, 3D model for the simulation of turbidity currents. All principal hydraulic properties of the flow and its responses to topography can be continuously monitored in 3D.

The present project is aimed to obtain the optimal palaeo-bathymetry and characteristics of the palaeo-flows reproducing the desired sediments distribution. For each bathymetry, different realistic flow conditions (position of the flow inlet, flow size and velocity, grain

distribution) were evaluated and analyzed, observing different possible scenarios in the palaeo-system.

One significant achievement is the verification of the most realistic palaeo-bathymetry: our model confirmed that the topography provided by Norwegian Energy Company was suitable to reproduce realistically the depocenters as mapped in the well-cores available. More information from the cores could give more indication about the nature of the flows (i.e. if they are erosional or depositional, grain size, flow direction, single surge or to multiple ones). In fact, several different scenarios could lead to similar depositional basins but only the finer structure observed in the cores could give indications to narrow the possibilities from several plausible flows to one specific one capable of creating the different layers observed in the cores.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California