Tolmount East

Tolmount East Gas Field Profile

Location and Geology

• The Tolmount East gas field is located in the southern North Sea, approximately 37km east of Flamborough Head and 152km from the UK/Netherlands median line, within Block 42/28d of the P1330 license.
• The field is situated in the Lower Leman Sandstone Formation Play Fairway, characterized by Aeolian dunes, fluvial sands, and local sabkha. The reservoir is linear with parallel faulting.

Ownership and Operatorship

• The Tolmount East field is jointly owned by Harbour Energy (50%) and Dana Petroleum (50%). However, some sources also mention Korea National Oil as a participant, though this may be an error or outdated information.

Discovery and Development

• The Tolmount Main field was first discovered in 2011. The Tolmount East well was drilled in 2019 and is a tie-back to the main Tolmount field, which was brought online in April 2022.
• The development well for Tolmount East was completed in late 2022, and the field was placed into production in December 2023. It is the first tieback to the Humber Gathering System (HGS).

Production Details

• The Tolmount East field is expected to produce around 150 billion cubic feet of gas. Peak production is anticipated in 2024, with approximately 2,520 cubic meters (or 1,000 m³) of gas per day, and 68 tonnes of condensate per day, followed by a gradual decline over the field's life.
• The field's production will contribute to the UK's gas output, currently accounting for about 1% of the country’s daily gas production.

Infrastructure and Operations

• The field is developed using a single development well, with provisions for up to two additional future wells. Gas, condensate, and any produced water are exported to the Tolmount Minimum Facilities Platform (MFP) via a new 4 km long 12" flowline. From there, the hydrocarbons are exported to the Centrica Storage Limited’s Easington Terminal onshore via the Tolmount export pipeline.
• The project involves multiple walk-to-work and subsea construction campaigns, as well as engineering and construction for topsides modifications.

Environmental and Carbon Footprint

• The Tolmount East project is designed to be carbon neutral across its full lifecycle, addressing Scope 1 and Scope 2 GHG emissions. The development incorporates optimized engineering designs to minimize the seabed footprint, reduce disturbance to ecological species, and lower embedded carbon required for construction.

Contractors and Services

• Key contractors involved include Rosetti Marino for the engineering, procurement, construction, installation, and commissioning of the Tolmount platform; Costain for the front-end engineering design (FEED) study for the subsea pipeline; Wood Group for FEED services; Hereema for the transportation and installation of the platform; and Saipem for pipeline EPCI works.

Future Plans and Associated Projects

• Harbour Energy is also working on other North Sea projects, including the Talbot project, a multi-well tie-back to the Judy platform expected to start up around the end of 2024, and the Leverett gas discovery, which could be a tie-back to the Britannia hub.

Field Life and Reserves

• The Tolmount East field is expected to continue production until it reaches its economic limit in 2046. As of the current data, the field has recovered about 5.07% of its total recoverable reserves.