Abstract: Topographic Controls on Turbidite Sandstone Reservoirs: Facies Models with a Physical Basis

Ben Kneller

Prediction of turbidite sandstone reservoirs in topographically-controlled 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 basin-floor features (e.g. salt domes) and basin-margin topography (e.g. fault scarps). 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 non-uniformity is a function of down-flow changes in gradient or confinement, and is therefore a function of the topography over which the flow is moving; flow unsteadiness is largely related to the triggering mechanism. These two terms can be combined in a powerful, physically-based facies model whi h predicts the relations between turbidite facies and the topographic elements of turbidite systems. The effectiveness of this model is demonstrated by application to an outcrop reservoir analogue in the Annot sandstones, SE France.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France