f The Use of Horizontal Wells to Optimise the Development of 2 Small, North Sea, Oil Fields

The Andrew and Cyrus fields are located in UKCS blocks 16/27a and 16/28, 230 km from Aberdeen. The reservoir is comprised of high net to gross Palaeocene, submarine fan sandstones. The oil and gas is trapped in four way dip closures over Permian salt domes. The fields were discovered in 1974 and 1979 respectively. Cyrus first oil production was in 1990 from a single well into a floating SWOPS vessel. Andrew field development was sanctioned in 1994, following an EWT in 1992, and production began in 1996 , 20+ years after its discovery. Horizontal production Wells, sub-sea technology on Cyrus; the Andrew Alliance and accelerated commissioning of a conventional platform design, transformed the discovertes from economically marginal to economically attractive developments.