Outcrop Analogues in Southern Utah Provide Improved Understanding of Marginal Eolian Reservoirs in the UK Southern North Sea

Taggart, Samantha¹, Gary Hampson¹, Matthew Jackson¹ (1) Imperial College London, London, United Kingdom

The Permian Rotliegend gas play of the UK Southern North Sea consists of eolian sandstones that pass laterally northwards into evaporate-rich lacustrine claystones. Previous development of the Southern North Sea basin has focused on the high quality eolian sandstones. However, as these are now maturing, focus has shifted to exploring the potential of the more heterogeneous marginal reservoirs (so-called “feather-edge” play). Vertical and lateral heterogeneity within these marginal reservoirs pose high risks when considering reservoir potential.

Four main facies, muddy sabkha, sandy sabkha, aeolian dune and fluvial, have been identified in a series of wetting up sequences from detailed sedimentary logs of cores from within North Sea quadrants 48 and 49. The well exposed Page (eolian/sabkha) and Cedar Mesa (eolian/fluvial) Sandstones in southern Utah are analogous to elements of the marginal Rotliegend play and have been studied at outcrop to investigate sedimentological heterogeneity at reservoir and inter-well scales.

Sedimentological logs and fence panels from these outcrop analogues have enabled the lateral extent of sandbody units and their connectivity to be mapped in three dimensions. Quantitative data collected from the field analogues constrains facies architecture and hence the vertical and lateral heterogeneity expected in the Rotliegend feather-edge play of the Southern North Sea.