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High Resolution Simulations of Turbidity Currents and River Outflows

High Resolution Simulations of Turbidity Currents and River Outflows. Eckart Meiburg UC Santa Barbara. Coastal margin processes. Turbidity current. Underwater sediment flow down the continental slope Can transport many km 3 of sediment Can flow O(1,000)km or more

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High Resolution Simulations of Turbidity Currents and River Outflows

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  1. High Resolution Simulations ofTurbidity Currents and River Outflows Eckart Meiburg UC Santa Barbara

  2. Coastal margin processes

  3. Turbidity current • Underwater sediment flow down • the continental slope • Can transport many km3 of • sediment • Can flow O(1,000)km or more • Often triggered by storms or • earthquakes • Repeated turbidity currents in the • same region can lead to the • formation of hydrocarbon • reservoirs • Properties of turbidite: • - particle layer thickness • - particle size distribution • - pore size distribution Turbidity current. http://www.clas.ufl.edu/

  4. Results: 3D turbidity current – Temporal evolution DNS simulation (Fourier, spectral element, 7x107 grid points) Necker, Härtel, Kleiser and Meiburg (2002a,b) • turbidity current develops lobe-and-cleft instability of the front • current is fully turbulent • erosion, resuspension not accounted for

  5. Filling of a minibasin (w. M. Nasr, B. Hall) Interaction of gravity currents with submarine topography:

  6. Turbidity current/sediment bed interaction (w. M. Nasr) ‘Flow stripping’ in channel turns: lateral overflows

  7. Couple turbidity current solver to reservoir simulator • Long term strategy: • carry out simulation of polydisperse turbidity current • obtain spatial grain size distribution of the deposit • convert grain size distribution into permeability and • porosity distribution • feed permeability/porosity distribution into reservoir simulator • carry out simulations of porous media displacement processes

  8. Channelization by turbidity currents: A Navier-Stokes based linear instability mechanism (with B. Hall, B. Kneller) Field data show regularly spaced channels along the ocean floor • Hydrodynamic instability?

  9. Sediment wave formation by turbidity currents (w. B. Hall, L. Lesshafft, B. Kneller) Large scale wave forms at the ocean floor • sediment waves are prime targets for oil reservoir formation • formed by turbidity currents and bottom flows; mechanism? • traditional assumption: lee waves, but no rigorous stability analysis available

  10. Sedimentation from river outflows (w. Peter Burns) • Leaking mode

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