MODELLING THE EFFECTS OF SALT-INDUCED TOPOGRAPHY ON DEPOSITION FROM TURBIDITY CURRENTS
Prediction of turbidite sandstone reservoirs in topographically variable systems is approached through a combination of physical and conceptual modelling; scaled physical analogues help to constrain geometries, while physically based genetic facies models predict the distribution of lithotypes. Data are presented for experimental gravity flows interacting with obstacles simulating salt-induced topography. Interactions between the flow and topographic features are dependent upon the shape and orientation of the obstacle, and upon its size relative to the height of the flow. Deposition of sediment from turbidity currents is as dependent on flow non-uniformity as it is upon unsteadiness; the nature and magnitude of flow nonuniformity are functions of down-flow changes in gradient or confinement, and it is therefore a function of the topography over which the flow is moving. This can be combined with the effects of flow unsteadiness to create a powerful, physically based facies model that predicts the relations between turbidite facies and the topographic elements of turbidite systems.