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.

The Huntington Oil Field is located in Block 22/14b in the Central Graben of the UK Continental Shelf. The reservoir is the Forties Sandstone Member of the Sele Formation, and oil production is from four production wells supported by two water-injection wells, tied back to the Sevan Voyageur FPSO (floating production storage and offloading unit). Initial estimates of oil-in-place were c. 70 MMbbl and the recovery factor at the end of 2017 after 4.5 years of production was 28%, which reflects the weak aquifer and poor pressure support from water injection. The Huntington reservoir is part of a lobate sheet sand system, where low-concentration turbidite sands and linked debrites are preserved between thin mudstones of regional extent. Within the reservoir, three of the thicker mudstone beds can be correlated biostratigraphically on a regional basis. This stacked lobate part of the system sits above a large-scale deep-water Forties channel that is backfilled by a system of vertically aggrading channel storeys. Despite the relatively high net/gross of the reservoir, the thin but laterally extensive mudstones in the upper (lobate) part of the system are effective aquitards and barriers to pressure support from water.

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis Session paper will review the planning, preparation, and execution of the installation of the Independence Hub facility in Mississippi Canyon Block 920. The scope of the paper will encompass the transport and installation of the suction piles, the transport of the integrated facility to the offshore installation site and the installation of the polyester moorings and steel catenary risers in record water depths.The focus of the paper will be to highlight the use of existing technology and some innovative solutions to accomplish the installation of a facility that challenges existing Gulf of Mexico equipment depth and capacity limits. The results will show that the methods employed minimize costs and improve construction and installation efficiency.The paper will identify the importance of technically sound but simple design concepts and operations plans required for an installation in 8,000 ft of water with specific contributions regarding transportation stability, polyester mooring deployment/construction-stretch removal, and deepwater SCR retrieval and transfer.