Inside Auk - anatomy of an Eolian oil reservoir

Conference · Wed Mar 01 04:00:00 EST 1989 · AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)

OSTI ID:6147278

Heward, A P

Auk field is located in the central North Sea UK sector, and produces from Permian Zechstein carbonates and the underlying Rotliegend sandstones. Thirty wells have been drilled at spacings between 70 m and 3.6 km. The Rotliegend is about 300 m thick and can be divided into five possibly distinct phases of desert sedimentation; the upper three of these are oil bearing with eolian slipface sands forming the main productive horizons. (1) The earliest deposits are localized fluviatile conglomerates which infill topography on the unconformity with the Devonian. (2) The overlying highly porous sands form a large wedge-shaped body onlapping the Devonian. They comprise predominantly eolian slipface sands with slipfaces oriented toward the southeast. (3) This interval represents a change in eolian deposition with a marked increase of tighter wind-ripple laminated sandsheet, dry interdune, and dune apron sands. This unit fluctuates in thickness by about one-third over the field area. Stacked dune slipface sands are oriented toward the east and cannot be correlated over a few hundreds of meters across wind. (4) An even greater proportion of wind-ripple laminated deposits are contained in this interval. Its geometry is that of a depositional mound 100 m thick and 7 km across wind. Dune and possibly dry slipface sands, oriented east, occur where it is thickest. Fine-grained eolian sands are banked up on its northern flank. (5) Finally, waterlain mass-flow sands partially infill depositional lows and appear to represent rainfall reworking of a largely abandoned erg. The marine Zechstein transgressed and draped remaining topography.

• Research Organization: Shell UK Exploration and Production, London (England)
• OSTI ID: 6147278
• Report Number(s): CONF-890404-
• Conference Information: Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Journal Volume: 73:3
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
ATLANTIC OCEAN
CARBONATE ROCKS
DEVONIAN PERIOD
EUROPE
GEOLOGIC AGES
GEOLOGIC DEPOSITS
MINERAL RESOURCES
NORTH SEA
PALEOZOIC ERA
PERMIAN PERIOD
PETROLEUM DEPOSITS
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEAS
SEDIMENTARY ROCKS
SURFACE WATERS
UNITED KINGDOM
WESTERN EUROPE