Viking Graben Fields
The Andrew and Cyrus fields lie in UK Blocks 16/27a and 16/28 at the junction of the Witch Ground Graben and the South Viking Graben. The Andrew Fields was discovered in 1974 with well 16/28-1, and Cyrus in 1979 with well 16/28-4. Both fields share a common reservoir the Paleocene Andrew Formation and both are sealed by the overlying Andrew Shale and Sele Formation. Similarly the traps for both fields formed above swells within Zechstein salt. The Andrew and Cyrus Fields differ in their petroleum content. Andrew contains both gas and oil (40API) while Cyrus contains only oil (30API).
Reserves for the Andrew Field are 140MMBBL based upon a 46% recovery factor using natural aquifer drive. The same mechanism will deliver 16.5MMBBL from Cyrus at a 21 % recovery factor. Production began from Andrew in July 1996. Cyrus production began in April 1990 using the SWOPS system until April 1992. The small field was subsequently tied back to Andrew.
Figures & Tables
Memoir 20 is the most comprehensive reference work on the UK’s oil and gas fields available. It updates and substantially extends Memoir 14 (1991), United Kingdom 0il and Gas Fields, one of the Geological Society’s best-selling books. This new edition contains updates on many of the ageing giant fields, as well as entries for fields either undiscovered or undeveloped when Memoir 14 was published.
The book is divided into nine parts covering the major petroleum provinces both offshore and onshore United Kingdom, from the Gas Basin in the southern North Sea to the Viking Graben in the northern North Sea, from the Atlantic Frontier to the Irish Sea and from the Wessex Basin to the East Midlands. Each part contains a reference map showing field locations. The introductory chapters reveal the stories behind the major plays and discoveries therein, and their tectonic and stratigraphic framework. There are two appendices: tabulated field data and a comprehensive list for all of the UK's 300+ oil and gas fields.