Laggan-Tormore: reservoir to sales production forecasting and optimization using an integrated modelling approach
K. Jones, D. Mackinnon, A. De Senneville, K. Watt, 2014. "Laggan-Tormore: reservoir to sales production forecasting and optimization using an integrated modelling approach", Hydrocarbon Exploration to Exploitation West of Shetlands, S. J. C. Cannon, D. Ellis
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Laggan and Tormore are gas-condensate fields in the West of Shetland region of the UK, to be developed as a 143 km subsea tie-back (twin 18″ flowlines) to a new onshore gas plant (Shetland Gas Plant, SGP). Condensate will be sent to the neighbouring Sullom Voe Terminal for stabilization and a new 30″ gas export pipeline will provide a route from the SGP to Total's St Fergus terminal on the UK mainland. The development is planned as a hub to enable future development of similar reservoirs in the region.
Production forecasting and field management are complex due to the evolving nature of the reservoir compositions over time, the back-pressure and flow assurance impacts of the long flowlines and final sales products being delivered at two remote terminals. This will be further complicated with the introduction of any additional fields, requiring an accurate understanding of field interactions, pipeline ullage, plateau extension and management of production allocation. To address these issues, Total E&P UK (TEPUK) have developed an integrated asset model (IAM) using state-of-the-art techniques to model the system from reservoir to final product sales. The IAM will be used to communicate a common geosciences and development understanding for forecasting and future development studies.
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This volume addresses the challenges facing explorers and developers alike in a region that is becoming a major focus of the petroleum industry in the United Kingdom, Faroes and North Norway. Several West of Shetland fields are still in the appraisal phase almost a decade after discovery. Sub-volcanic exploration risks remain high: sub-volcanic structural traps are imaged poorly, and so the geophysical community is responding with the application of latest technology. The more simple reservoirs might not be large enough to prompt informed and speedy development decisions; larger fields might have a combination of complexities, requiring a phased approach to the development. Infrastructure has been slow to arrive and planned developments have been subject to dramatic swings in fiscal regime ranging from special allowances to unexpected tax increases.
Environmental challenges are significant when moving into more remote, deeper water. The perception of these challenges by the third parties has become much more acute. To sustain its right to operate, the industry has to demonstrate safe drilling operations and appropriate response capability with government agencies.