The use of field analogues in the correlation and static reservoir methodology used in the Tern Field, Northern North Sea, UK

Abstract

Three-dimensional modelling of reservoirs deposited in different depositional environments suggests that they require different correlation methodologies. An example drawn from the Tern Field, located in the Brent Province in the Northern North Sea, offshore UK, shows that the Rannoch Formation, interpreted from core as a shoreface deposit, can successfully be correlated using a sequence stratigraphic framework, constrained by flooding surfaces. In contrast the younger Lower Ness Formation, interpreted as dominantly coastal plain in character, also required a sequence stratigraphic approach, but one based upon broader depositional cycles. In the latter correlation, it was important not to correlate isolated sandbodies within the channel belts, which would have led to an overestimation of reservoir volumes. Field analogues from the Book Cliffs of Utah, and Breathitt Group of Kentucky support the concepts behind the contrasting approaches to correlation, while not necessarily providing precise depositional analogues. The interpolation of reservoir properties in the Tern Field reservoir model demonstrates that the correlation strategy is robust, and provides evidence of a northwesterly progradation direction within the Rannoch Formation of the Tern Field.