Project Profile
Value: US$237 million
Location: Southern North Sea, United Kingdom Continental Shelf, on the Norfolk coastline
Field Type: Gas
Water Depth: 28m
Estimated reserves: 97 bcf
First Production: May 2012
Ensign offshore gas and condensate field is located 80km away from the English coastline and 78km away from the UK / Dutch median line at a water depth of 28m (92ft) in the southern North Sea. The field lies in blocks 48/14a and 48/15a of the United Kingdom Continental Shelf (UKCS). Centrica Energy Upstream owns and operates the field. First gas from the field was produced in May 2012.
The Ensign Gas field was discovered by Shell / Esso in 1986 with the drilling well 48/14-2. The field was further apprised by Conoco in 1988 with the drilling well 48/15a-6. The field was later acquired by Venture North Sea Gas and NSGP, which drilled two additional appraisal wells namely 48/14-5 and 48/14-6. Centrica gained ownership of the field upon acquiring Venture North Sea Gas and NSGP in 2009. The field development approvals were received from the Department of Energy and Climate Change (DECC) in 2011. Centrica invested about US$237 million on the field development. The appraisal wells were drilled through hydraulic well fracturing techniques to improve the gas recoverability. The process involved pumping high pressure fluids into reservoir rock formations for creating fractures and opening up the rock to allow the flow of gas.
The gas field has been developed by the installation of a Not Permanently Attended Installation (NPAI). The production and processing infrastructure at the field comprises of three production wells, including two platform wells and one subsea well tied back to a 24km long ten-inch export pipeline connected to the Audrey A platform. Gas from the Audrey platform is exported via a 20in pipeline to the Lincolnshire Offshore Gas Gathering System (LOGGS) operated by ConocoPhillips, and further exported to Theddlethorpe Gas terminal. The field has estimated gas reserves of about 97bcf. The field is expected to produce about 2.3 million metric standard cubic metres (MMSm3) of gas a day.
Operators:
Centrica Upstream Energy (Formerly Venture Production Plc).
NSGP (Ensign) Ltd.
Both operators are now fully owned by Centrica.
Contractors:
Aker Solutions: Subsea production well controls
CTC Marine Projects: Pipeline trenching
GE Oil & Gas: Subsea christmas trees (xmas trees)
Heerema: Not permanently attended installation EPC
Oceaneering International: Umbilicals
Petrofac: Audrey B platform modifications FEED
Seaway Heavy Lifting Engineering BV: Platform installation
SLP Engineering: Turnkey engineering and construction EPC
Subsea 7 S.A.: Flowlines and subsea works