Laggan - Tormore
The development is a long-distance 141 km tie-back of sub-sea wells to the new Shetland Gas Plant (SGP) at Sullom Voe on the Shetland Islands, which has a 500 mmscf/d capacity.
Identical 6 slot template manifolds are installed on both the Laggan and Tormore fields, with the template concept driven by a need for high reliability in the harsh weather environment. Dual production headers connect each manifold to dual 141km 18” diameter multi-phase flowlines. Tormore ties-in to the flowlines at the far extremity, 141km from Sullom Voe, and Laggan ties-in to them 16km downstream of Tormore, 127km from Sullom Voe.
Production from Laggan and Tormore fields is commingled with the combined fluids processed together through the SGP. Production from Laggan and Tormore is measured subsea by multiphase flow meters. Discrete metering packages meter production streams before custody transfer of condensate to the BP operated Sullom Voe Terminal for processing and re-delivery; and gas for export into the FUKA Pipeline System via the new Shetland Island Regional Gas Export System (SIRGE System).
First gas from the fields was achieved in 2016, and work is currently ongoing to tie-in the Edradour and Glenlivet fields into the Laggan-Tomore infrastructure.
Under the current expectations of long-term oil and gas prices and indications given by investors, the infrastructure is expected to be operational until 2026.
Provisions for Third Party Access
Laggan-Tormore facilities form a major new infrastructure development intended to export “stranded” gas from the West of Shetland region to the National Grid gas entry point at St Fergus. In order to accomplish this role, the Laggan-Tormore facilities are designed to accommodate gas from 3rd parties wishing to enter the system for transportation and/or processing. The key elements of this design philosophy are as follows:
- Tie-in points on the Laggan and Tormore manifolds
- Spare capacity in the umbilical to add additional satellite developments.
- Hot-tap Ts for tie-in to the multiphase pipelines between Laggan and SGP (3 on each flowline and the MEG pipeline).
- Capability to operate the multiphase pipelines in LP and HP modes.
- Space at the SGP facilities to add extra process units in order to increase capacity.
Work has been ongoing to provide the Rosebank Owners with an option to tie-in a gas export solution via the Tormore manifold.