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Sedimentary Architecture of the Upper Wolfville and lower Blomidon Formations, Minas Sub-basin, Bay of Fundy, Nova Scotia, Canada

Jonathan, Atunima E.¹; Hodgetts, David²; Redfern, Jonathan³
¹Earth Sciences, University of Manchester, Manchester, United Kingdom.
²Earth Sciences, University of Manchester, Manchester, United Kingdom.
³Earth Sciences, University of Manchester, Manchester, United Kingdom.

The overall aim of this research is to understand and characterize fluvial deposits quantitatively in three-dimensions, and using the resulting geostatistical information to produce realistic geocellular reservoir analogue models. The well exposed outcrops of Late Triassic fluvial sandstones in the Fundy Rift Basin of Canada present exceptional analogues for hydrocarbon reservoirs in the North Sea and other similar fluvial systems, making them ideally suited to this project.

This study concentrates on the architectural description and modelling of the fluvial dominated, syn-rift upper Wolfville and lower Blomidon formations. Traditional sedimentological field methods are combined with lidar digital data capture techniques to describe and interpret facies geometry and distribution. Changes in facies distribution and architectural style are used to subdivide the stratigraphic succession into two parts. The basal section (upper Wolfville) consists of channel sandstone bodies alternating with limited overbank mudstone deposits. Within the upper Wolfville Formation, a dominant trend of upwards finning is observed with sedimentary structures ranging from ripples, parallel lamination, planar to trough crossbedding. Whereas the upper section (lower Blomidon) is dominated by laterally continuous fine sand to muddy units interpreted as lacustrine deposits.

Maximum hydrocarbon recovery in clastic reservoirs is a function of how well we understand the exact architecture of sand bodies and barriers to fluid flow. Modelling of fluvial reservoirs can be very unreliable when only conditioned to seismic and well data as is the case in the sub-surface. By using outcrop analogue data to condition the geological model, the uncertainty in the facies distribution is reduced.

 

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012