Play Concepts Based on New Stratigraphic Methods - Two Examples from the Dutch

Abstract

In the Northern Offshore of the Netherlands 'Upper Jurassic' strata are mostly limited to the Central Graben and Terschelling Basin. Outside the Central Graben and the Terschelling Basin only thin veneers of these strata occur on the fringing highs as the Schill Grund High and the Step Graben. The 'Upper Jurassic' strata are an important target for the oil and gas exploration. The geology of the non-marine to shallow marine strata is complex. The combination of lateral facies changes, repetitive log and facies characteristics in time, sea-level and climate changes, salt tectonics and structural differences hamper straightforward seismic interpretation and log correlation. A tectono-stratigraphic approach has led to the identification of three tectono-stratigraphic sequences. Sequence 1 (Callovian - lowermost Kimmeridgian) comprises the initiation of the Central Graben. Sequence 2 (lower Kimmeridgian - lower Portlandian) comprises the initiation of the Terschelling Basin. During sequence 3 (upper Portlandian - Ryazanian) the Dutch offshore is draped by a regional transgression. In this presentation the enhanced exploration potential resulting from the tectono-stratigraphic approach, is exemplified by two potential play concepts.