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Palaeogene Remobilised Sandstones in the Central North Sea - Implications for Hydrocarbon Migration
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 73rd EAGE Conference and Exhibition incorporating SPE EUROPEC 2011, May 2011, cp-238-00130
- ISBN: 978-90-73834-12-5
Abstract
Remobilised sandstones are widely recognised in many North Sea oilfields, e.g. Volund, Alba, Gryphon, and Chestnut fields. This paper presents evidence that multiple-statigraphic level sand injectite complexes have acted as fluid conduits, thus explaining why valid traps in some areas are not charged. One such example lies in UKCS block 22/2, where the Chestnut field has been charged due to one such sand injectite complex. In this example, a Middle Eocene reservoir at the down-dip, terminal lobe of deepwater system has been charged. Underlying the reservoir is a sand injectite complex which connects as deep as the Forties Sandstone Member. The implications of this are significant, as it would imply potentially valid Paleocene hydrocarbon traps with overlying sand injectites may be dry. In order to test this hypothesis; Paleocene closures, with and without overlying sand injectites, were examined. Paleocene Structures with proximal remobilised sandstone were found to be dry. These Eocene conical injectites, in some cases, appear to cut the Top Balder seismic reflector. Log signatures and core data demonstrate the features to be homogenous and structureless, and their mapped occurrence appears to be random. It is contended that these features are intruded from underlying, late Paleocene sands.