(Adds details, background)
BAKU, Sept 17 (Reuters) - BP is to suspend operationsat one of its platforms in the Caspian Sea for plannedmaintenance, a spokeswoman for BP Azerbaijan said on Thursday.
"Chirag oil platform will be suspended this autumn," TamamBayatly said by telephone.
She did not specify when the maintenance was expected tostart and how long it would last.
Chirag is one of main offshore oilfields in Azerbaijanoperated by BP.
The company had suspended operations at another majorplatform in the Caspian Sea, West Azeri, for planned maintenanceon May 21 for 22 days.
Crude oil and condensate production in Azerbaijan fell to27.9 million tonnes in the first eight months of 2015 from 28.6million tonnes a year earlier, mainly due to declining output atthe Azeri, Chirag and Guneshli fields, according to officialAzeri statistics.
Daily oil output at these oilfields, which account for mostof Azerbaijan's production, fell to an average 641,000 barrelsper day (bpd) in the first half of 2015 from 656,000 bpd in thesame period last year and 661,000 bpd in the first quarter ofthis year, BP said in August.
Crude oil and condensate production in Azerbaijan fell to41.9 million tonnes last year from 43.1 million in 2013. Naturalgas output was 29.2 bcm in 2014, according to Azeri statistics.
Oil production rose to 14.2 million tonnes in the first fourmonths of 2015 from 13.6 million a year earlier, but started todecline in May as BP suspended operations at West Azeri.
BP and its partner, SOCAR, said in 2013 that production hadstabilised. Total oil output rose in 2013 for the first timesince 2011, but the decline resumed in 2014.
Azerbaijan plans to produce 40.7 million tonnes of oil and30.2 bcm of gas in 2015. (Reporting by Nailia Bagirova; Writing by Margarita Antidze;Editing by Jack Stubbs and Jane Merriman)