Pierce

Location

The Pierce Field is situated approximately 165 miles (265 km) east of Aberdeen, Scotland, in the Central North Sea of the UK Continental Shelf. It is located in Blocks 23/22a and 23/27.

Geology and Reserves

The field features twin salt diapirs that trap oil and free gas in the Paleocene–Eocene Forties Sandstone Member reservoir. The proven and probable reserves of the field include 86 million barrels of oil and 250 billion cubic feet (bcf) of gas.

Discovery and Production History

The Pierce Field was discovered in 1975. It secured approval from the UK Department of Trade and Industry (DTI) in August 1997, and oil production commenced in 1999. Initially, the field produced only oil, with gas being re-injected into the reservoir.

Redevelopment

In 2019, Shell UK and Ithaca Energy (UK) took the final investment decision (FID) on the Pierce Depressurisation Project. This redevelopment project aimed to enable the field to produce both gas and oil. Key modifications included:

• Upgrading the leased floating production, storage, and offloading (FPSO) vessel, Haewene Brim, in a dry dock at Aibel’s yard in Haugesund, Norway, for six months.
• Installing a new subsea gas export line to connect the field to the SEGAL pipeline system, which transports gas to the St Fergus terminal, north of Aberdeen.

Production Facilities

The FPSO vessel, Haewene Brim, extracts and processes crude oil from the Pierce North and South fields. The oil is stored in cargo tanks and exported directly via shuttle tankers. The primary separation processing facilities include:

• Production manifold
• Subsea flowlines
• Crude oil heaters
• First and second stage oil/gas/water separation
• Test separator
• Crude oil export pumps

The gas treatment facilities include:

• Gas recompressor (recovery) system
• Glycol dehydration unit
• Two-stage gas export compressor
• H2S management (scavenger chemical injection).

Ownership and Partners

The project is a joint venture between Shell companies (operator, 92.52%) and Ithaca Energy (UK) Limited (7.48%). The Shell companies involved include:

• BG Great Britain Limited (20%)
• Enterprise Oil Limited (EOL) (42.79%)
• Shell EP Offshore Ventures Limited (SEPOV) (39.73%)
• Shell Upstream Overseas Services (I) Limited (SUOSL) (10%).

Production Capacity

Following the redevelopment, the Pierce Field is expected to more than double its production to over 30,000 barrels of oil equivalent per day (boe/d) at peak, with more gas produced than oil.

Environmental and Regulatory Context

The redevelopment of the Pierce Field is aligned with the North Sea Transition Deal, a partnership between the UK Government and the offshore oil and gas sector aimed at reducing greenhouse gas emissions. The project must also comply with the revised UK tax regime, which includes an increased energy profits levy.

Investment and Future Plans

The Pierce Field redevelopment is part of Shell’s larger investment plan, which includes £20-25 billion ($24.87 billion to $31.09 billion) in the UK energy system over the next decade, subject to board approval and a stable investment climate.