Project Profile
Value: US$2,123 million
Location: Norwegian sector of the North Sea
Start-up Year: 2012
Water Depth: 70m
Upstream Oil Reserves: 182 million bbl
Valhall is an oil field in the Norwegian sector of the North Sea. Discovered in 1975, production began in 1982 and is expected to continue until 2050. Valhall is located in 70 metres of water. It produces from chalk in the Tor and Hod Formations of Late Cretaceous age. The reservoir depth is approximately 2,400 metres. In 1981, the field was developed by three fixed platforms and commenced production in 1982. In 1996, further field development included a Wellhead Platform (WP) installed on the southwest section of Valhall. A year later, the field produced 84,500 bopd from 33 wells. As the field aged and slowly declined in production, additional wells, 90 in total, were drilled.
Recently, the field was revamped in order for the complex to receive its power from shore, making Valhall the world\'s first offshore oil field to receive its electricity from land, with no need for on-platform generation. BP replaced subsiding facilities, added two new facilities to the complex and added a new power system in place of the old offshore gas turbines. The new power system will delver 78 megawatt power for the running of the oil field. Valhall is expected to produce until 2050 and during its lifetime, it will be one of the most environmental friendly fields offshore Norway.
The project will see a processing Platform (capacity 150,000 b/d) with living quarters, as the preferred option for development. The water injection project on Valhall involves constructing a platform connected to the existing wellhead installation. There will be four new pipelines (6.5km each) and three riser caissons to be installed in water depth of 70 metres. There will be fourteen wells for water injection and an additional production well, which are planned in addition to the seven extra producers already due to be drilled. The water injection is expected to improve the oil recovery factor from 31% to 38%. This would yield roughly 29 million scm in additional oil.
Decommissioning
The Valhall complex comprises six separate manned platforms: the Quarters Platform (QP), the Drilling Platform (DP), the Production and Compression Platform (PCP), the Wellhead Platform (WHP), the Water Injection Platform (IP), the new combined Process and Hotel Platform (PH) and two unmanned flank platforms, Valhall South Flank platform and Valhall North Flank platform.
QP, DP and PCP were the first platforms to be commissioned at Valhall. Production from the field started in October 1982. The PCP was decommissioned in October 2013, following the commissioning of the new PH platform earlier that year.
The new PH platform has an oil production capacity of 120mbopd, can handle gas volume of 143mmscf/day and has a total liquid capacity of 200mbpd (oil and produced water).
In April 1996, the wellhead platform (WP) was installed and first oil was produced in June. The WP has 19 well slots and was built at a total cost of NKr1.5bn including the well drilling costs.
The decommissioning of the old facilities is estimated to continue until 2025.
Operators:
Aker BP: Operator and 40% interest
Pandion Energy: 10% interest
Hess Corporation: 50% interest
Contractors:
Kvaerner: Delivery of the topside and steel jacket substructure
Subsea 7: EPCI contract
Apply Leirvik: Contracted for the delivery of an emergency shelter and helicopter deck
DeepOcean: Subsea inspection, maintenance and repair (IMR) activities
Allseas: Transport, installation and removal (T,I&R) services.
ABB: Underwater power link
Aker Solutions: Steel substructure
BIS Industrier: Insulation, scaffolding and surface treatment (ISO contract)
Constituent companies awarded FEED:
Wood Group
Fabricom
Force Technology Norway AS: Inspection and corrosion management services
J P Kenny Norge AS: FEED contract
Heerema: EPC - Deck and process modules
Maersk: Drilling using the jack-up rig, XL Enhanced 4
Moorings Systems: Installation of flexible export flowline
Mustang Engineering: FEED contract
Nexans: HVDC and optic fibre cables
Odfjell Well Services (OWS): Tubular running services
Prosafe: Accommodation support vessel contract
qedi: GO Technology® project management system
Saipem SpA: EPC - 180 man living quarters, power from shore module offshore and three local equipment rooms
Subsea 7 Inc.: Pipelines and three riser caissons
Solberg & Andersen: Valves/actuators
Technip: Intervention work on LOFS
Technocean: Integrated subsea services
WGP Exploration: Life of Field Seismic (LoFS) survey
Aker Solutions: Contract to provide engineering, modifications and maintenance services, as well as a number of decommissioning services. The contract has a fixed period of five years valued at as much as NOK 3.2 billion. It also contains options to extend the agreement by as many as four years. The accord starts on December 1, 2015 on expiration of an existing agreement for similar services. The work will be managed and executed by Aker Solutions\' maintenance, modifications and operations units in Stavanger and Sandnessjøen and at the company\'s fabrication yard in Egersund. (November 2015)
Sub Contractors:
DOF Subsea Norway AS: Subsea installation work
HB Rentals: Four modules
Scanmudring: Dredging work for Technocean