Project Profile
Value: Undisclosed
Location: Southeast of Gannet accumulations, Central North Sea, 200km east of Aberdeen, UK
Reserves: 6.7 million tonnes of oil and 0.61 billion cubic metres of gas
Production: 17,735bopd and 7 million cubic feet per day of gas
Water Depth: 4,500ft and 7,600ft
The Banff field lies 25km south east of the Gannet accumulations in the Central North Sea, 200km east of Aberdeen, UK. It is located predominantly in the Conoco-operated block 29 / 2a, extending into the neighbouring block 22 / 27a operated by Ranger. In October 2003, Canadian Natural Resources (CNR) took over Conoco\'s share of interest in the field. As of July 2007, the partners of the field include CNR International (65.33%), CNR International Developments (22.28%) and Dana Petroleum (12.40%). CNR holds 26.2% working interest in the field through its subsidiary Ranger. The reservoir lies between 4,500ft and 7,600ft, and consists of Palaeocene sands underlying a steeply dipping and faulted Upper Cretaceous (Maastrichtian) chalk formation, located around a salt diapir piercement. Earlier, the field was estimated to have reserves of about 60 million barrels of 38-39° API gravity oil and approximately 39 billion cubic feet of gas. In 2007, the recoverable reserves were estimated to be 6.7 million tonnes of oil and 0.61 billion cubic metres of gas.
Drilling
Banff was produced from two production wells (29 / 2a-B1 and 29 / 2a-B2), which were drilled and tested using the semisubmersible drilling rig Glomar Arctic III, and tested at a cumulative rate of 17,735bopd and 7 million cubic feet per day of gas. Each of the wells encountered more than 3,000ft of hydrocarbon-bearing section in the chalk reservoir. Conoco carried out a six-month production test using a floating production unit with a shuttle tanker offtake. The assessment began in September 1996. The Sedco 707 floating production semisubmersible drilling rig was modified to accommodate processing facilities with the associated risers and controls. Production started February 1999 with an early production rate ranging between 6,000 and 34,000bopd for an initial three days. Production was later stopped due to operational conditions with the leased Ramform FPSO. The FPSO was removed from the field for repair and refitting in 2000. The repair work was completed and oil production restarted in March 2001. The natural gas reinjecting programme to increase the reservoir\'s recovery from the field was started in the fourth quarter of 2004.
Banff development
Banff is developed by a new floating production, storage and offtake (FPSO) system owned and operated by Petroleum Geo-Services UK Limited (PGS). The production system, infield flowlines and gas-export pipeline were supplied by PGS under a production services contract with Conoco and its co-venturers. PGS owns the facilities with production operations sub-contracted to Atlantic Power. In 1997, NKT Flexibles was given a contract by PGS Offshore Technology on behalf of Conoco to supply dynamic risers and static jumpers for the FPSO. The contract work also included detailed design, engineering, procurement, manufacturing, certification and testing. The Banff field development is the first time the Ramform hull design has been used as a floating production system.
Contract
In December 2009, the contract for installing the replacement of subsea control modules and flexible jumpers for the field was given to Subsea 7. The newbuild double-hull production vessel was fabricated at the Hyundai Mipo yard in Ulsan, South Korea. It has a storage capacity of 120,000 barrels (onboard) plus an extra 500,000 barrels. The vessel is 395ft long by 175ft wide. The ship\'s weight, excluding the helideck and topsides modules, is approximately 8,000t. The 3,500t topsides can process 60,000bopd and 90,000bpd of fluid. They also have the necessary facilities for gas dehydration, compression and export, water injection, produced water treatment and disposal, metering, stabilised crude export, utility systems, process / well control and shutdown systems. Oil is exported via a double-hulled shuttle tanker in 500,000 barrel loads. The gas is exported through a 6in, 8km pipeline, which will tie-in to the 36in CATS trunkline.
Operators:
Canadian Natural Resources: Operator with 87.61% interest
Dana Gas: 12.40% interest
Contractors:
FMC: Provider of the two horizontal production trees
Petroleum Geo-Services UK Limited (PGS): Floating production, storage and offtake (FPSO) system
PGS: Supply of production system, infield flowlines and gas-export pipeline
Subsea 7: Installing the replacement of subsea control modules and flexible jumpers for the field
Transocean: Drilling contract
Hyundai Heavy Industries: Fabrication of the newbuild double-hull production vessel
Wood Group Integrity Management: Manage pipelines
Subcontractors:
Atlantic Power: Production and operations of the FPSO facilities
NKT Flexibles: Supply dynamic risers and static jumpers for the FPSO