Laggan & Tormore—Development of Two New Deepwater Gas Condensate Fields and Associated Gas Export Infrastructure
Authors: Cutler Jeremy 
Published: December 2009

ABSTRACT
The Laggan and Tormore gas condensate fields are situated in 600m water depth some 140km north-west of the Shetland Islands. The region is served by limited oil and gas infrastructure and so called "stranded gas" fields have been left undeveloped to date; primarily due to the significant investment required to establish an export route to market in this remote and harsh environment.
After several years of extensive development engineering studies and commercial negotiations, the Laggan and Tormore partners, led by TOTAL E&P UK Ltd (TEP UK), are moving towards sanction of a major project that could lead to first production of gas from this challenging region by 2014. The proposed project facilities consist of a subsea template-manifold above each of the Laggan and Tormore reservoirs with production from up to eight subsea wells commingled and exported multiphase to the Shetland Islands via two 18" 140km rigid steel flowlines. A new gas processing facility sized for 500 MMscfd and operated by TEP UK will be constructed onshore close to the existing Sullom Voe oil terminal. A new 30" 230km gas export pipeline sized for circa 665 MMscfd will transport the processed gas to a tie-in point on the FUKA pipeline close to the abandoned MCP01 platform.
Development of the Laggan-Tormore gas fields would represent a major achievement for the licence partnership and a significant milestone in the overall development of the West of Shetland region. The "Shetland Islands Regional Gas Export" system (SIRGE) will offer a new export route for gas from an area previously bottlenecked by the existing limited gas export infrastructure. Linked to the new onshore gas processing terminal, SIRGE should reduce the development cost for new entrants, thereby promoting the future growth potential of the region.
The West of Shetland region is unique for its combination of extreme metocean conditions and a demanding environmental context characterised by its distinctive wildlife and rugged onshore terrain. The long distance subsea tie-back chosen for Laggan-Tormore brings with it significant technical challenges in terms of flow assurance and construction / installation planning together with a complex regulatory framework associated with environmental considerations, multiple stakeholders and land access approvals.
Reaching this milestone has involved a significant investment in both financial and human resources to complete the technical engineering and sub-surface studies as well as the complex commercial negotiations to define the eventual development concept and gas evacuation route. The Third Party Investment Process carried out in 2008 offered the key West of Shetland stakeholders an opportunity to invest in a gas evacuation system sized for the region.
This paper summarises the Laggan-Tormore development process to date as well as the key technical challenges to bring this major new project to fruition and establish a new gas export infrastructure serving the West of Shetland region in years to come.