Lateral accretion in a straight slope channel system: an example from the Forties Sandstone of the Huntington Field, UK Central North Sea

Abstract

Abstract A rich dataset of core, well logs and 3D seismic data has been integrated to establish a depositional hierarchy of a Paleocene-aged, Forties slope channel system of the Huntington Field, Block 22/14b of the Central North Sea. The reservoir consists of a mix of high-concentration turbidites and muddy and sandy debrites deposited as a series of laterally offset, slope channel fills. Seismic data reveal that the channels were remarkably straight and devoid of meander bends, more commonly associated with sinuous slope channel networks. Paradoxically, the internal offlapping architecture draws close comparisons with lateral accretion packages that are widely accepted to be the products of secondary flow circulation around sinuous channel bends. The straight nature of the Huntington channels precludes such an interpretation but can be explained as a consequence of Coriolis effects acting upon suspension-dominated flows in Northern Hemisphere high latitudes, resulting in the preferential accretion of sediment along the right-hand bank (when viewed downstream) and leading to the eventual lateral avulsion of the channel. The observed architecture has been incorporated into a reservoir model in order to characterize the static connectivity of the field that will in turn serve as a basis for understanding production behaviour.