Series of rift basins formed along East Greenland during Late Jurassic break-up of the Pangea super-continent. In Jameson Land, sand-rich shelf edge slope basin floor systems dominated during the early, Callovian Kimmeridgian syn-rift stage. These well-exposed systems may serve as useful field analogues for a poorly understood but important type of hydrocarbon reservoir.
The uppermost Callovian Middle Oxfordian Olympen Formation consists of 1. coarsening-upward cross-stratified sandstone units representing offshore prograding sand-wedges on the shelf edge, 2. elongate or sheet-like massive sandstone bodies representing a variety of sediment gravity flows on the slope and basin floor, and 3. mudstone representing settling from suspension on the slope and basin floor.
Down-slope transformation of sand-grade gravity flows and resultant depositional architecture can effectively be demonstrated from systematic spatial and temporal variations in massive sandstone geometry. Lenticular, down-slope elongate sandstone bodies occur randomly scattered within prograding shelf-edge wedges and slope mudstone. They represent dense, non-turbulent to fully turbulent flows, filling pre-existing gullies that formed by retrogressive slumping on the slope. Sheet-like sandstones encased in mudstone were deposited from unconfined turbidity flows at the base-of-slope and on the basin floor.
The resulting reservoir-analog is bipartite with an upper reservoir-level consisting of up to 150 m thick, well-structured sandstone deposited along the shelf edge, and a lower reservoir-level consisting of up to 70 m thick, amalgamated sheet-like massive turbidite sandstones, deposited along the slope basin floor transition. The two levels are connected by stringers of gully-filling turbidite sandstone, which may serve as migration conduits for hydrocarbons.
AAPG/SEPM: From Outcrop to Simulation I: Using Outcrop Data to Build Reservoir Models