Pengembangan subsea dapat memberikan 50% dari produksi UKCS pada tahun 2013, naik 30% dari tahun lalu, kata MD Roland Festor UK di Subsea Europe conference di London.

Penulis : Jeremy Beckman

Total’s largest and longest-producing UK asset is Alwyn in the northern North Sea, east of Shetland. Alwyn came onstream in 1987 and was expected to shut down 12 years later, Festor said. This year, it ‘celebrated’ its 21st anniversary, and is expected to be in business for a further 21.

Following the addition of a second platform on the Dunbar field in the early 1990s, Total focused on extending production through a series of subsea tiebacks, starting with Ellon and Grant in 1994-98, followed by the four Nuggets fields, Forvie in 2005, and most recently Jura, connected this year to the Forvie manifold. Islay is to follow in 2010.

These subsea developments have helped maintain plateau output of 140,000 boe/d at the Alwyn complex, Festor said, and they have ensured that all tail-end production from the Alwyn and Dunbar fields will remain economic.

Total also may boost its subsea output in the UK central North Sea by tying back the Kessog gas-condensate field to the Elgin/Franklin facilities, depending on the results of an extended well test. The main challenge on Kessog is high temperature, Festor said – all seals on the 15,000-psi, 73-ton subsea tree must withstand conditions of up to 185º C.

However, subsea production also has its downsides, Festor claimed. ‘The major problem is that spare parts are not available on some of our older developments.’

‘Also, there is a lack of people [in the industry] knowing what we are talking about. And even with some of the newer subsea systems, there is a problem with quality control – sometimes they don’t work, or the efficiency is not as good as with topsides production systems. Additionally, there is a shortage of installation vessels, so when production stops, you have to wait, for example, for a diving support vessel to come, and when it does come, it costs a fortune.’

Festor added that subsea vendors must do more to ensure their systems work, ‘because there is technology in it that is not our expertise. We would like to see improvements in the reliability of our systems.’