Martin Linge

Location and Discovery

The Martin Linge oil and gas field is located in the North Sea, approximately 42 kilometres west of the Oseberg field, near the border of the UK continental shelf. It is situated at a water depth of 115 metres.

The field was discovered in 1978, initially known as the Hild field, with the discovery well 30/7-6 R drilled in that year. It was further appraised by four additional wells drilled between 1981 and 1984.

Ownership and Operator

The Martin Linge field is currently operated by Equinor Energy AS, which acquired a 51% equity stake from Total E&P Norge in March 2018 for $1.45 billion. Following this acquisition, Equinor became the operator with a 70% ownership, while Petoro holds the remaining 30%.

Reservoir Details

The Martin Linge field features a complex reservoir structure with multiple layers:

• The main reservoirs are located in Middle Jurassic sandstones of the Brent Group at depths ranging from 3,700 to 4,400 metres. These reservoirs contain gas and condensate under high pressure and high temperature (HPHT) conditions.
• Additionally, there is an oil reservoir in the Frigg Formation from the Eocene age, located at a depth of approximately 1,750 metres. This oil is described as a viscous, thin oil accumulation overlain by a small gas cap.

Field Development

The Plan for Development and Operation (PDO) for the Martin Linge field was submitted in January 2012 and approved by the Norwegian Parliament in June 2012. The development involves:

• An integrated wellhead, production, and quarters platform atop a steel jacket.
• A permanently anchored floating, storage, and offloading unit (FSO), which is the converted shuttle tanker Hanne Knutsen. The FSO is equipped with Wash Tank Technology for oil processing.
• The field is connected to an onshore power supply via the world’s longest alternating current (AC) subsea cable, stretching 162 kilometres from Kollsnes in Hordaland county. This power from shore reduces CO2 emissions by approximately 200,000 tonnes annually.

Production and Export

Production at the Martin Linge field began on June 30, 2021.

• The field is expected to reach a plateau production of around 115,000 barrels of oil equivalent per day (boe/d).
• Gas produced at the field is transported via a new pipeline connecting to the existing Frigg UK pipeline (FUKA) and then to the Shell-Esso Gas and Liquid (SEGAL) terminal at St. Fergus in Scotland.
• Oil is processed on the FSO and then transported by shuttle tankers. Residual water from the FSO is transferred back to the platform for re-injection into the wells.

Infrastructure and Technology

• The field infrastructure includes a standalone fully-integrated production platform with living quarters.
• The platform is operated from an onshore control room in Stavanger, with offshore operators using tablets to collaborate with the onshore team. This setup utilizes digital solutions to monitor and optimize operations, reducing operational costs and energy consumption.
• The power supply system, provided through a 163km-long 145kV high-voltage alternating-current (HVAC) submarine cable, is a key feature of the project, significantly reducing CO2 emissions.

Challenges and Delays

The development of the Martin Linge field faced several challenges:

• The project was initially scheduled to start production in 2016 but was delayed due to a tragic crane collapse incident at the Samsung Heavy Industries shipyard in South Korea in May 2017, which resulted in the deaths of six people and injured 20 others.
• The capital expenditure (Capex) for the field significantly exceeded initial estimates, totaling NOK 63 billion ($7 billion) compared to the original plan of NOK 31.5 billion ($3.5 billion).

Environmental Considerations

The use of power from shore is a significant environmental benefit, reducing CO2 emissions by approximately 200,000 tonnes each year, equivalent to the emissions from 100,000 automobiles. The emissions from the field are about 1 kg of CO2 per barrel of oil produced.

Oil Characteristics

The Martin Linge crude oil is categorized as a heavy naphthenic crude oil with the following characteristics:

• Density of 0.93 g/mL.
• Low evaporative loss and low wax content (0.67 wt. %).
• Low asphaltene content (0.11 wt. %).
• Forms stable, high-viscous water-in-oil emulsions with rapid and high water uptake (~ 80 vol. %).

In summary, the Martin Linge oil and gas field is a complex and technologically advanced project that highlights innovative approaches to oil and gas production, including the use of power from shore and advanced digital solutions for operational efficiency.