Reservoir characterisation of deepwater massive sandstones: case studies from the Numidian Flysch and Mediterranean

The deep-water turbidite play is currently one of the most prolific and important in hydrocarbon exploration and production. Within this play, the best reservoirs are those that occur in thick sequences of deep-water massive sandstones (DWMS). These are very thick (1- 50m) sand beds or units that are devoid of primary sedimentary structures, deposited by high-density turbidity currents and/or sandy debris flows. They are commonly associated with thin-bedded turbidites, hemipelagites and other deep-water sediments, and display excellent and uniform reservoir properties and geometries. Typically, they also give rise to sand injection structures within the superjacent and laterally adjacent sediments, and display a variety of feather-edge relationships with the associated facies. The Oligo-Miocene Numidian Flysch system from both northern Tunisia and Sicily includes excellent examples of DWMS, which are the subject of ongoing investigations. This contribution aims to present an overview of what we know about DWMS, with particular focus on their reservoir characteristics, to introduce some new data on examples from the Mediterranean region, and to place the Numidian system within the context of DWMS globally.