Leman South

Location

The Leman field is situated in the southern North Sea, approximately 48-53 kilometers northeast of the Bacton gas reception terminal on the Norfolk coast.

Discovery and Production

The Leman gas field was discovered in late 1965, and production began in 1968. The field has been a significant contributor to the UK's natural gas supply over the decades.

Infrastructure

The field is supported by multiple platforms, including:

• Leman F & G platforms: These are Normally Unattended Installations (NUIs) that have been in operation since 1987. They are set to cease production in the mid-2020s and are scheduled for decommissioning following regulatory approval.
• Leman 27H and 27J installations: These platforms are also part of the Leman field and are operated by Perenco UK Limited. They provide facilities for the extraction of natural gas and its export to the Leman 49/27A (27A) installation and then to the Bacton Gas Terminal (BGT) via subsea pipelines.
• Leman A complex: This serves as a central hub for the field, receiving gas from the various satellite platforms before it is exported to Bacton.

Decommissioning

Decommissioning plans are underway for several platforms within the Leman field:

• Leman F & G platforms: Shell UK has received regulatory approval to decommission these platforms, including the topsides, jackets, production pipelines, power cables, and associated stabilization features.
• Leman 27H and 27J installations: Perenco has submitted plans for the decommissioning of these platforms, which includes flushing and isolating the pipelines and assessing them against best available techniques (BAT) and best environmental practices (BEP).

Operators and Ownership

The Leman field is operated by multiple companies:

• Shell UK: Responsible for the Leman F & G platforms.
• Perenco UK Limited: Operates the Leman 27H and 27J installations, with significant equity interests held by Perenco UK Limited and other companies like Rockrose UKCS Limited.

Geology and Petroleum System

The Leman field is part of the Carboniferous-Rotliegend Total Petroleum System, which is characterized by the juxtaposition of thermally mature coals and carbonaceous shales (source rock), sandstones of the Rotliegend sedimentary systems (reservoir rock), and the Zechstein evaporites (seal). This system is one of the most intensely explored in the world and has significant potential for undiscovered resources.

Environmental and Regulatory Aspects

The decommissioning plans for the Leman field platforms must adhere to strict environmental regulations. The plans include thorough environmental appraisals and assessments to ensure compliance with best available techniques (BAT) and best environmental practices (BEP).

Project Timeline

• Discovery: Late 1965
• Production Start: 1968
• Cessation of Production for Leman F & G: Mid-2020s
• Decommissioning Approval for Leman F & G: January 2024
• Cessation of Production for Leman 27H and 27J: December 15, 2021.