Models of Continental Sequence Stratigraphy Revealed from Chemical and Mineralogical Correlation in the Triassic Sherwood Sandstone Group, United Kingdom

Neil Meadows
Redrock International, Wirral, United Kingdom

The prolific hydrocarbon reservoir of the Early Triassic Sherwood Sandstone Group in NW England comprises a 1km+ thick sandstone dominated succession that includes depositional facies representing fluvial channels, aeolian sandsheets, sandflats and playa lakes. The current stratigraphic nomenclature for the Sherwood Sandstone uses the vertical association of these facies to define formation boundaries but makes no allowance for areal variations that have become apparent between wells and outcrops as a result of an expanding database due to hydrocarbon exploration and development in the area.

The application of chemical stratigraphy coupled to both detrital mineralogy and sedimentary facies has correlated individual sandbodies, identified sequence boundaries and can be used to model the detailed heterogeneity of this complex reservoir. Systematic changes in the provenance of the sandstones provide the key to this revision of Sherwood Sandstone stratigraphy. This modelling has revealed that the major controls on the areal and vertical variations in sedimentary facies can be ascribed to a combination of climatic and tectonic parameters in which the stratal architecture generated is dependent on the relationship between sediment flux, fluvial discharge and the generation of accommodation space.

A predictive model is proposed that allows for the interaction of these various parameters and can have significant applications to other reservoirs in which continental deposits dominate the succession.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005