BP is to suspend operations at one of its platforms in the Caspian Sea for planned maintenance, a spokeswoman for BP Azerbaijan said on Sept. 17.

"Chirag oil platform will be suspended this autumn," Tamam Bayatly said by telephone.

She did not specify when the maintenance was expected to start and how long it would last.

Chirag is one of main offshore oilfields in Azerbaijan operated by BP.

The company had suspended operations at another major platform in the Caspian Sea, West Azeri, for planned maintenance on May 21 for 22 days.

Crude oil and condensate production in Azerbaijan fell to 27.9 million tonnes in the first eight months of 2015 from 28.6 million tonnes a year earlier, mainly due to declining output at the Azeri, Chirag and Guneshli fields, according to official Azeri statistics.

Daily oil output at these oilfields, which account for most of Azerbaijan's production, fell to an average 641,000 barrels per day (bpd) in the first half of 2015 from 656,000 bpd in the same period last year and 661,000 bpd in the first quarter of this year, BP said in August.

Crude oil and condensate production in Azerbaijan fell to 41.9 million tonnes last year from 43.1 million in 2013. Natural gas output was 29.2 bcm in 2014, according to Azeri statistics.

Oil production rose to 14.2 million tonnes in the first four months of 2015 from 13.6 million a year earlier, but started to decline in May as BP suspended operations at West Azeri.

BP and its partner, SOCAR, said in 2013 that production had stabilised. Total oil output rose in 2013 for the first time since 2011, but the decline resumed in 2014.

Azerbaijan plans to produce 40.7 million tonnes of oil and 30.2 bcm of gas in 2015.