Paleogene Sandstone Intrusions in the Eastern North Sea - Implications for Reservoir and Play Evaluation

Abstract

Dedicated Fluids and fluid flow This study presents sandstone intrusions and fluid migration from the Eastern North Sea area south of the Siri Canyon and east of the Central Graben and thereby introduces possible new hydrocarbon plays in a hitherto underdeveloped area. Two sets of intrusions are recognized. The first set is represented by conical to tabular high-amplitude cross-cutting reflections within the Oligocene succession above the Ringkbing Fyn-High. The second set is recognized in the Eocene succession north of the D-1 fault. The intrusions in both areas are associated with a pronounced forced-folded surface onto which onlaps are observed. The onlaps and the forced-folded surfaces indicate that intrusion took place c. 25 Ma in the first area and c. 34 Ma in the second area. The suggested model of generation for the intrusions involves remobilization of source sand units within the Paleocene to Eocene succession due to overpressure build-up facilitated mainly by differential loading and influx of fluids from the deeper successions. The study thus highlights the impact of differential loading on sand remobilization and furthermore describes potential fluid migration from a deep thermogenic source located in the Ringkbing-Fyn High area.