MassFLOW-3DTM as a simulation tool for turbidity currents: some preliminary results - From Depositional Systems to Sedimentary Successions on the Norwegian Continental Margin - page 586

MassFLOW-3D TM as a simulation tool for turbidity currents:
some preliminary results

RICCARDO BASANI*, MICHAL JANOCKO † , MATTHIEU J.B. CARTIGNY ‡ ,
ERNST W.M. HANSEN* and JORIS T. EGGENHUISEN ‡
* Complex Flow Design A.S., P.O. Box 1248, 7462 Trondheim, Norway
† Department of Earth Science, University of Bergen, 5007 Bergen, Norway
‡ Department of Earth Sciences, Utrecht University, PO Box 80021, 3508 TA Utrecht, Netherlands

ABSTRACT

Turbidity currents are the most important mechanism for the dispersal and deposition
of sand in the deep-sea setting and thus the main phenomenon leading to the forma-
tion of oil and gas reservoirs in deep water deposits. The flow characteristics of turbid-
ity currents are difficult to observe and study from the modern environment and their
experimental approximations in the laboratory are typically limited by scaling issues,
unrealistic flume geometries and short durations. Computational fluid dynamic (CFD)
analysis, realised as numerical simulations, has been developed to fill the gap between the
small and large scale, integrating data from theory, nature and experiments. CFD can also
shed light on flow parameters which are so far impossible to deduce from experimental
and field studies, such as detailed density and turbulent kinematic energy distributions.
The deterministic process modelling CFD software MassFLOW-3D™ has been developed
and used successfully to construct a three-dimensional model for the simulation of
turbidity currents. All principal hydraulic properties of the flow (e.g. velocity, density,
sediment concentration, apparent viscosity, turbulence intensity and bottom shear
stress) and its responses to topography can be monitored continuously in three dimen-
sions over the whole duration of the turbidity current. In this paper, comparisons made
between the numerical output of MassFLOW-3D TM and the physical experiments are
presented. In addition, the code is used to model the spatial characteristics, velocity
structure and deposits of high-density turbidity currents and the flow dynamics of
low-density turbidity currents in a sinuous channel. The numerical simulations show
close fit to experimental sandy turbidity current dynamics for flows with sediment
concentrations up to 27%. However, despite this initial success, on-going customisa-
tion and validation of these models, together with implementation of improved sub-
routines aimed at sediment transport and deposition, is essential in improving the
computational code and our understanding of the natural phenomena.

Keywords: computational fluid dynamics, CFD, deterministic process simulations,
turbidity currents, sinuous channels.

INTRODUCTION poses practical problems, exploration in the near

future is bound to move further seaward as many
of the hydrocarbon fields on the Norwegian
Continental Shelf have now passed their produc-
tion peaks and face total depletion within the first
half of the 21st century (Norwegian Petroleum
Directorate, 2009). Similar exploration strategies
have already been established in major petroleum
provinces around the world, including offshore
West Africa, the Gulf of Mexico and offshore

Sandstone successions of turbiditic origin have
long been recognised as important hydrocarbon
reservoirs on the Norwegian Continental Shelf
(e.g. Hastings, 1986). Despite the fact that these
deposits are mainly high-risk targets (complex
geometries, uncertain stratigraphic closures and
facies heterogeneity) and occur predominantly in
deep-water offshore areas where the development