The Cook Formation Reservoir Architecture, Stratigraphy and Paleogeography in the Tampen Spur Area

Abstract

This thesis describes the development of the prograding and aggrading, Lower Jurassic Cook Formation across Knarr Field and Garantiana discovery located in the Tampen Spur area in the Northern North Sea. 11 facies, 5 depositional element and 7 facies association has been combined to established three correlation. The Cook Formation has been divided into three higher order sequences lower middle and upper Cook member. The Lower and Middle Cook Formation have been interpreted to be deposited in a main tide-dominated environment, and Upper Cook Formation is deposited in a mix tide- and wave-dominated environment. The lower Cook member represent two prograding tide dominated deltas, oriented east-west. The middle Cook member display and aggrading unit, representing two prograding delta which retreats an changes to estuaries, which is oriented south-east to north-west. The upper Cook member display a tide dominated prograding delta in the Knarr Field, and a faintly wave-dominated shoreface in the Garantiana discovery. The systems got transgressed and a faintly wave-dominated lower shoreface was established in both the Knarr Field and Garantiana discovery before the whole system got drowned. The lower Cook member was deposited during tectonic quietness, while middle and upper Cook member was deposited a minor rifting event.