The Gina Krog platform is tied into Sleipner A. (Credit: Ole Jørgen Bratland/ Equinor ASA)
Gina Krog has been constructed on a seabed platform, with wells drilled by a movable jack-up drilling rig. (Credit: Ole Jørgen Bratland / Equinor ASA)
The Gina Krog field was first discovered in 1974 by the 15/5-1 well. (Credit: Equinor/ Ole Jørgen Bratland)

The Gina Krog oil and gas field (formerly known as Dagny) is located in the North Sea, approximately 230km southwest of Stavanger, Norway.

The field is operated by Equinor with an interest of 58.7%. The other partners are KUFPEC Norway (30%) and PGNiG Upstream Norway (11.3%).

Gina Krog was first discovered in 1974.

The plan for development and operation (PDO) was approved in 2013, and the oil and gas field commenced production in June 2017.

The partners invested around NOK31bn ($3.7bn) for the development of the field.

In 2019, net production from Gina Krog averaged 1.8 thousand barrels of oil equivalent per day (mboepd).

Gina Krog Field Location

The Gina Krog field is located on the Utsira High in the central part of the North Sea, around 30km northwest of Sleipner field.

The field lies in blocks 15/5 and 15/6 of production licences PL 303, 048, 029 and 029B in the North Sea. The Sleipner platform is situated around 30km away.

Water depth at the site is around 120m.

Discovery and Appraisal

The Gina Krog field was first discovered in 1974 by the 15/5-1 well.

Initially, it was considered a small gas field. However, it was again reviewed after oil and gas were proven in the neighbouring structure Gina Krog Øst (previously Dagny) in 2007.

Delineation conducted between 2008 and 2011 proved contact between Gina Krog and Gina Krog Øst and identified significant volumes of oil under the entire structure.

Gas, condensate and oil were found in the Ermintrude prospect in 2007, while appraisal wells drilled between 2008 to 2011 proved an oil column under the gas.

The field was renamed as Gina Krog in 2013.

Gina Krog Reservoir and Reserves

The hydrocarbons from Gina Krog are recovered from sandstone of Middle Jurassic age in the Hugin Formation.

The reservoirs are segmented and have varying thickness and quality. They are situated in depths of 3,300m-3,900m.

The reservoir is capped by Heather shales, while the base constitutes a coal layer on top of the Sleipner Formation.

Overall, the field has 14 faulted segments, of which five are referred to as reference segments and are included in the reserves estimate.

Gina Krog is expected to host 225 million barrels of oil and gas, which will also help in extending the life of nearby Sleipner.

Gina Krog Field Development

Gina Krog development planned to deploy a standalone, 20-well, 70-bed jacket platform with a designed production capacity of 10,000Sm3/d of oil and 9,000,000Sm3/d of gas.

The project now uses Randgrid Floating Storage and Offloading (FSO) unit. Originally a shuttle tanker, the vessel was converted into an FSO unit for the operations.

The initial plan involved drilling 11 production wells and three injection wells.

The field initially produced by gas injection in most reservoir segments, but from 2021, all segments are produced via pressure depletion.

Stabilised oil is stored in the FSO and shipped to refineries by shuttle tankers. Rich gas is processed at the Sleipner A platform, while condensate is transported via the Sleipner R platform, and then processed at Kårstø into natural gas liquids (NGL) products.

Sales gas is exported from Sleipner A via Gassled (Area D) to the UK and EU markets.

Equipped with additional well slots and topsides capacity for multiple unproven targets, the field will support future tie-ins.

A new 23km long pipeline between Gina Krog and Sleipner A is set to replace the existing Rangfrid FSO in 2024.

The pipeline solution is expected to reduce the annual operating costs and carbon dioxide emissions from the field by around 18,000 tonnes per year.

Contractors Involved

Aibel, which manufactures key infrastructure for the energy industry, conducted Front End Engineering Design (FEED) study for the topsides on the Gina Krog platform.

In 2011, HFG Engineering secured the contract for the FEED study of the Gina Krog jacket. After the completion of the FEED study, in February 2013, Heerema Vlissingen won the engineering, procurement and construction contract for the launch jacket and pre-drilling wellhead module.

Korean shipbuilding firm Daewoo Shipbuilding & Marine Engineering (DSME) designed and constructed the topsides for the Gina platform.

Mærsk Drilling was awarded the contract for production drilling on the field, while Aker Solutions conducted modification work on the Sleipner A to tie-in the gas production from Gina Krog.

ROCKWOOL Technical Insulation was engaged for the supply of SeaRox fire-rated insulation for the project’s topsides escape tunnel.

In May 2013, Teekay Offshore Partners won the contract to covert Randgrid shuttle tanker into a FSO unit for the Gina Krog field. The conversion cost around $220m, which included the cost of purchasing the remaining 33% ownership interest in the shuttle tanker.

In September 2013, GE Oil & Gas secured the contract to provide DSME with turbomachinery equipment and services for the Gina Krog platform.

Norway-based subsea contractor Ocean Installer also selected GE Oil & Gas for subsea tie-in connection systems to support the development of the offshore field.

In 2020, Aibel secured an Engineering, Procurement, Construction, Installation and Completion (EPCIC) contract for the electrification of Gina Krog project.

Aibel was also awarded an implementation contract to modify Gina Krog and Sleipner A platforms in order to connect them by a new 23km pipeline.

In May 2021, ABB commenced the pilot project to facilitate digital transformation of monitoring of critical electrical systems on the offshore platform.