The UK North Sea is a core producing area for Lundin Petroleum providing significant production from the three fields; Broom, Heather and Thistle.
Introduction
Lundin Petroleum has working interests in 4 production and 10 exploration licences on the United Kingdom Continental Shelf (UKCS). The major operated assests include two mature producing fields, Thistle and Heather, and the Broom subsea development which is tied back to the Heather platform. The Company’s total 2P reserves from its United Kingdom producing assets is 82.1 MMboe.
Broom Field
The Broom field is located approximately 7 km to the west of the Heather platform at the western edge of the North Viking Graben. The field comprises a Middle Jurassic oil accumulation formerly known as West Heather, discovered by well 2/05-8B in 1977, and the North Terrace discovered by well 2/05-5 in 1976.
The field was granted separate field status and governmental approval for development in 2003. The development targets the West Heather accumulation with four producers and two injector wells developed as a subsea tie-back to the Heather platform.
The Heather platform provides gas-lift and water injection to enhance the Broom field performance. It also processes and meters the produced fluids for onward shipment to the Ninian platform and ultimately to the Sullom Voe terminal.
The Broom phase II was successfully completed in 2005 with the drilling of a new infill well in West Heather and one new development well in the North Terrace.
An infill well was completed in the first quarter 2008 on the Broom field which came on stream in April 2008. An additional infill well is likely in 2010.
The field is currently producing from three producers in West Heather and one producer in North Terrace. Two water injector wells provide reservoir pressure support in West Heather.
Heather Field
The Heather oil field is located in Block 2/5, some 120 km northeast of the Shetland Islands in the UK Sector of the Northern North Sea. The field was discovered in 1973 by Well 2/5-1, which encountered oil in Middle Jurassic Brent Group sandstones.
Development of Heather began in 1977 involving a single steel platform. First oil production was achieved in October 1978. Oil is exported to Ninian for landing at Sullom Voe and gas is imported from WELGAS.
The Heather platform acts as the host for the nearby Broom field sub-sea development providing services to the Broom wells and processing the produced fluids. The Heather field is located in the East Shetland Basin to the west of the North Viking Graben. It is one of the most westerly of the fields in the Brent Province and close to the East Shetland Platform. The nearest fields in this area include Cormorant and North West Hutton to the northeast in Quadrant 211, and Lyell and Ninian to the east in Quadrant 3. The small, decommissioned Emerald field is situated to the south in Quadrant 2 and 3.
The Heather field comprises a tilted fault block structure delineated by faults to the south and east. The reservoir occurs as shallow-marine and deltaic sandstones of the Middle Jurassic Brent Group, which average 125 to 370 feet in thickness. Reservoir sandstones are of variable character from narrow fluvial channels to sheet-like sand bodies. Mudstone interbeds adversely affect reservoir pressure communication. The reservoir is extensively faulted. Porosity and permeability values are generally moderate. The reservoir contains black oil with a gas/oil ratio of 650 scf/stb. The produced gas was initially re-injected into the reservoir but Heather now imports fuel gas from the WELGAS system. Water injection is used to maintain pressure. Recoverable proven and probable reserves have increased by 13.5 mmboe as a result of the completion of redevelopment studies for the Heather field based on new 3D seismic acquired. Development drilling is under consideration for 2011.
Thistle Field
The Thistle oil field is located in the south eastern portion of Block 211/18a and marginally in Block 211/19a, in the UK Sector of Northern North Sea. Thistle was discovered in 1973 by Well 211/18-2, which encountered under saturated oil in good quality Middle Jurassic Brent Group sandstones at around 9000 feet TVDSS.
A 60-slot, single steel jacket platform was installed in 1976 and oil production began in February 1978.
A long term investment programme to redevelop the Thistle field commenced in 2007. The redevelopment involves the reinstallation of the Thistle drilling rig. A new 3D seismic survey over the field has been acquired. The forward plan for Thistle involves new production well drilling and workover activity to enhance production levels. Further facilities investment will continue to ensure increased facilities uptime and an extended life for the Thistle platform.
As a result of a subsurface review multiple new drilling and workover opportunities have been identified for redevelopment and has resulted in an increase of proven and probable reserves of 13.1 mmboe. An extended programme of drilling and workover projects will commence in 2010 using the rebuilt Thistle drilling facilities.
The Deveron field is a separate small accumulation, lying some 3 km to the west of Thistle in Block 211/18a. Production is via three wells drilled from the Thistle platform. The field commenced production in September 1984 and has been in decline since 1987.
The installation of facilities to provide transportation services for oil export from West Don and South West Don is being completed and will provide tariff income and reducing the net operating cost of the Thistle field.
Oil export was initially via a SALM (Single Anchor Leg Mooring) loading system, however, since December 1978, oil has been exported through the Brent pipeline system to Sullom Voe via Dunlin and Cormorant South.
Peik Field
Lundin Petroleum has an interest in the undeveloped Peik gas/condensate field which straddles the United Kingdom and Norwegian median line. The asset includes a 33.3% interest in UK Block 9/15a, which includes the Peik Field and an 85% of UK Block 9/10b. Development studies and economic analysis are ongoing.