Jette Field, North Sea, Norway

Jette (formerly Jetta) field is located in blocks 25/7 and 25/8 of the production licence 027 D in the Norwegian North Sea. The field is one of the smallest to be developed in the North Sea. It lies in 127m (417ft) of water, about 6km from ExxonMobil's Jotun field.

Det norske oljeselskap is the operator of the field and holds an 88% interest. Petoro holds the remaining 12% interest. Jette is the first field to be developed by Det norske as an operator.

The project was approved by the Norwegian Petroleum Directorate in February 2012. The development is estimated to cost NOK2.5bn ($439m). First production is expected in the first quarter of 2013. During the first year the field is expected to produce 14,000 barrels of oil equivalent.

Although Jette is a small field, its development represents significant benefits for the operator and for Norway. Small fields such as Jette can be rapidly put into production using existing infrastructure. It also helps in making maximum utilisation of the infrastructure.

With the development of the Jette field, Det norske can gain insights into the risks and benefits involved in developing comprehensive projects. The project is expected to be the first step for Det norske to focus on future developments on the Norwegian Shelf.

Discovery of Jette oil field

Jette was discovered in October 2009 with the drilling of the 25/8-17 well. The well was drilled to a depth of 2,208m and struck oil in the Ty formation. The reservoir thickness was less than expected and a limited amount of oil was discovered.

The 25/8-17A sidetrack well was drilled in November 2009 by the Bredford Dolphin Rig to a depth of 2,154m, to appraise the field. The well penetrated the Heimdal formation.

Geology and reserves of the Jette reservoir

The Jette reservoir lies at a depth of over 2,000m in the Palocene-age Heimdal Formation.

The field is estimated to contain about 14 million barrels of oil equivalent. Oil resources are estimated at 1.6 million cubic metres and gas resources at 0.4 billion cubic metres.

Jette offshore project development

The Jette field will be developed through two horizontal wells tied back to the Jotun field. The hydrocarbons produced from the field will be mixed with the output from the Jotun field on the Jotun B platform. The mixed output will then be sent to Jotun A floating production, storage and offloading (FPSO) vessel for processing and export.

In May 2012, Transocean Barents semi-submersible rig begun the first phase of drilling at the field. An observation well will be initially drilled at Jette North followed by the production wells. Transocean Barents is expected to remain at the field until August 2012.

Jotun A FPSO

Jotun A was converted from an AFRAMAX size tanker. It is 223.5m long and 41.5m wide with a processing capacity of 145,000 barrels per day. The vessel is installed in 126m of water and is equipped with processing facilities, living quarters and offloading facilities.

Contractors for the Jette field development

Aker Solutions was awarded a NOK60m ($10.5m) contract to supply subsea umbilical for the field. The scope of supply includes a 6km long electro-hydraulic stainless-steel umbilical, which will feature a 3in gas-lift line and perform electrical, hydraulic and methanol injection functions. Aker is expected to deliver the umbilical in the third quarter of 2012.

Cameron International was contracted to supply the subsea production systems for the field. The $56m contract includes the supply of wellheads, trees, controls, pipeline end manifolds and related equipment.

Specialised Management Services was subcontracted by Cameron to manufacture and supply a hydraulic power unit and an umbilical termination unit.

Subsea 7 won a $60m engineering, procurement, fabrication and installation contract. It will be responsible for tie-back of the two production wells. The detailed scope of the contract includes the supply of a 6km flexible flowline and jumpers, and installation of the 6km umbilical, X-mas trees, protective structures and other equipment.