f Exploration and Development of the North Sea Chalk Low Permeability System

This talk characterises the North Sea Chalk hydrocarbon play as a low permeability system. The low vertical and lateral permeabilities are responsible for phenomena which include tilted oil-water contacts and non-structural trapping mechanisms, as seen for example in the Halfdan Field. Predicting the petroleum system requires an understanding of hydrocarbon entry points, the permeability within the Chalk at the time of hydrocarbon emplacement, and the factors controlling lateral migration, which occurs at geological time scales. It is this slow lateral migration that results in dynamic and non-structural traps. An additional consequence of low permeabilities is low recovery rates in the absence of significant natural fracturing or induced fractures.