Intrachannel Architecture and Reservoir Heterogeneities Within Sand-Rich Carboniferous Slope Channels, Northern England, UK

Ian Kane¹, Ole J. Martinsen², and William D. McCaffrey^1
1Institute of Geological Sciences, University of Leeds, Leeds, United Kingdom
²Research Centre, Norsk Hydro, Bergen, Norway

The Late Mississippian Pendle Grit Formation represents a sand-rich slope to toe-of-slope channel complex deposited during the earliest major phase of siliciclastic input into the Craven Basin of northern England; a period which marked a widespread transition from carbonate- to siliciclastic-deposition across Europe and parts of North America. At the base of the system a thick (>400 m) succession of basinal mudstones are overlain by sand rich submarine slope channels with no apparent precursor events. The sand rich system was highly focused along its axis, thinning out towards its lateral margins into a series of isolated shale-encased sand bodies. Within the channels, seemingly tabular sandstones are bound by parallel surfaces draped by micaeous organic rich sandstones and shale-clast horizons; internally the sandstones contain highly complex amalgamation surfaces. The generally low amplitude of internal erosion and apparent lack of tractional structures lead us to place the Pendle Grit at the lower slope to toe-of-slope boundary where sediment was dumped rapidly but with larger or more efficient flows capable of bypassing and scouring surfaces. We present a study of architectural complexity and facies variability within this sand-rich system based on traditional geological techniques including mapping and section measurement; these data are used in conjunction with digital outcrop modeling to create models of system development that can be directly applied to subsurface data sets.

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