Effective teamwork between operators and suppliers has resulted in the completion of a highly efficient maintenance programme on Erskine, one of Chevron Upstream Europe’s (CUE) offshore installations, which has significantly boosted production performance.
Erskine is a gas condensate field that was discovered in 1981 in Block 23/26 in the Central North Sea. It was the first high-pressure, high-temperature field to be developed in the U.K. Continental Shelf, achieving first production in December 1997. It comprises a normally unmanned installation (NUI) which is remotely controlled from BG Group’s Lomond platform. An 18.6 mile (30 km) pipeline links the two facilities.
Processing of hydrocarbons takes place in a dedicated module on the Lomond platform. Gas and condensate are exported separately to BG Group’s North Everest platform before gas is finally exported via the Central Area Transmission System, while condensate is exported through the Forties Pipeline System.
BG Group and CUE have been working together on a large scale maintenance campaign to upgrade the Lomond hub to improve the efficiency of Erskine production, part of which comprises the cleaning and inspection of the 30 kilometre pipeline using a practice called ‘pigging’ with devices known as ‘pigs’.
Andy Brooks, Erskine Asset manager, explained: “Pigging involves inserting a pig into an oversized section in the pipeline known as a ‘pig launcher’ located on the Erskine Platform. The launcher is then closed and the pressure-driven flow of the product in the pipeline is used to push it along the pipe until it reaches the receiving trap called the ‘pig catcher’ located at Lomond. Carrying out this process enables us to clean and inspect the pipeline.
“By developing a joint vision for the campaign with BG Group and securing committed integrated input from the Erskine Asset and Intervention Team, Facilities Engineering Pipelines Group including pigging vendor companies, Logistics, BG onshore and Lomond offshore teams, we ran a total of 14 pigs, including an intelligent pig, which was essential for proving the long term integrity of the pipeline.”
The work took place over three mobilisations spanning a period of three months and, along with BG’s major refurbishment and maintenance programme on Lomond to improve long-term reliability, has resulted in all five Erskine wells coming online for the first time in two years. The daily production rate is now the highest it’s been in two years, at approximately 27,000 barrels of oil equivalent per day, and the combined production from Erskine and Lomond is at its highest since changing to a single train operation. Daily production efficiency is currently sitting at more than 90 per cent.
Steve Cox, BG’s Vice President UK Operated Assets said: “The recent pigging campaign is a great example of the ongoing success of the collaboration between the two companies,” a sentiment echoed by Dave Dillard, General Manager of CUE’s UK Operated Assets, who added: “With Erskine back on line, the teams are on course to deliver against their performance metrics for 2015 – a position Erskine hasn’t been in for a number of years. These results highlight the impact of exceptional teamwork and reinforce how a collaborative approach can add real value to the business.”
The Erskine Field is operated by Chevron North Sea Limited (50 percent) with BG International Limited (29.30 percent), BG North Sea Holdings Limited (2.70 percent) and Serica Energy (UK) Limited (18 percent) holding non-operated interests in the field.
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