The influence of stratigraphy and facies distribution on reservoir quality and production performance in the Triassic Skagerrak Formation of the UK and Norwegian Central North Sea

Stratigraphy, depositional facies and proximal-distal position within a depositional system are identified as controls on reservoir quality and dynamic reservoir performance in the Triassic, fluvial dominated, Skagerrak Formation reservoirs of the UK and Norwegian Central North Sea. Core sedimentological analysis from across the basin links decreasing trends of channel facies proportion and channel package thickness with increasing floodplain and splay facies proportions and their respective package thicknesses. These trends are considered to represent the proximal to distal transitions of distributive fluvial systems (DFS). Depositional facies are shown to strongly control static and theoretical dynamic reservoir quality using porosity-permeability cross-plots and stratigraphically modified Lorenz plots using conventional core plug data. This linkage of stratigraphy, depositional system position, facies proportions and package thicknesses with static and theoretical dynamic reservoir performance is used to predict pressure depletion profiles in various settings of Triassic reservoirs of the Central North Sea beyond major areas of well and field control in UK Quads 22 and 30.