Nine weeks of maintenance at UK's Buzzard oilfield in 2014

LONDON, Feb 7 (Reuters) - Britain's biggest oilfield, Buzzard, is expected to undergo a total of nine weeks of maintenance in 2014, according to the latest information seen by Reuters.

Two weeks of maintenance are planned at Buzzard in May, four weeks in August and three weeks in September, according to details outlined in a Suncor investor presentation released on Feb. 3.

Suncor, which has a 29.9 percent stake in Buzzard, announced second and third quarter maintenance at the field in its fourth quarter earnings release. The second quarter maintenance came as a surprise to the market.

Duration, timing and production impact details were given in Suncor's investor presentation. The work in May and August is estimated to have an impact on crude volumes of around 55,000 bpd apiece. The September work is expected to have an impact of about 15,000 bpd.

Buzzard is the biggest contributor to the Forties crude stream, one of the four crudes that underpins the Brent benchmark. The field has a maximum operating capacity of about 210,000 barrels per day (bpd).

It has already experienced four unplanned outages this year. Analysts at JBC Energy said the extended planned turnaround may be a bid to stabilise output.

"This implies that Brent prices will see spikes going forward, as Forties is generally the price-setter for the global benchmark," the analysts said in a note on Friday.

Buzzard is operated by Nexen (KSE: 005720.KS - news) , a unit of Chinese state company CNOOC (HKSE: 0883.HK - news) . Nexen told Reuters that it wanted to improve Buzzard's reliability in 2014.