Effect of Surface Morphology from Sediment Deposition Patterns: Potential to Use Field Data as a Control from 3-D Geological Models

Deirdre Duggan¹, David Waltham², Mike Krus¹, Zsolt Schleder¹, and Stuart McLean^1
1Midland Valley Exploration, Glasgow, United Kingdom
²Department of Geology, Royal Holloway, University of London, Egham, Surrey, United Kingdom

The impact of surface morphology on the distribution of sediment deposits has long been acknowledged, but recognising its effect is often difficult as the original surface morphology is obscured by both the deposited sediments and later geological processes. Analogue and numerical modelling provide the opportunity to identify the direct impact of the surface morphology on the deposition pattern of sediment deposits. This interaction between surfaces and subsequent deposition is often key to identifying petroleum reservoirs and migration pathways, and plays a role in the distribution of economic alluvial ore deposits for mining.

Using a using a particle flux numerical model for turbidite flow, the difference between axial and lateral sediment input to a graben is studied. Key differences in the sediment distribution depending on the sediment source area and sediment type are highlighted. The newly deposited sediments are then deformed by lateral compression to investigate how they react to tectonic deformation. The effect of this deformation on the apparent pattern of sediment deposition is investigated.

Using this approach allows the effect of the initial surface morphology on the distribution of the deposit to be distinguished from the later effect of tectonic processes. The results of the computer modelling are compared to a selection of field examples to show how the numerical forward modelling techniques can be used to provide a more complete picture of the structural and sedimentological history of a region. Knowledge gained from this process can be used as analogues in modelling reservoir extent, and in identifying reservoir sweet spots in down dip situations.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas