Turkmenistan says gas field in world's top five

ASHGABAT, Oct 14 (Reuters) - Turkmenistan's South Iolotan-Osman gas field has been confirmed among the world's five biggest after an audit by British firm Gaffney, Cline & Associates (GCA), the state-owned news agency said on Tuesday.

Turkmenistan, which sells most of its natural gas to Russian gas export monopoly Gazprom (GAZP.MM), has ambitious plans to supply China, Pakistan and India but needs to confirm its massive reserves before embarking on new projects.

The Central Asian country hired GCA to carry out an independent reserve audit of South Iolotan-Osman, state-owned Turkmen Khabarlary news agency reported.

Representatives of GCA in London and Moscow could not be reached for comment and the company's Singapore office declined to comment on the announcement.

The agency quoted GCA Business Development Manager Jim Gillett as saying his company estimated South Iolotan/Osman held between 4 trillion and 14 trillion cubic metres (tcm) of gas, bigger than Russia's Shtokman field even at the lower estimate.

"This makes South Iolotan-Osman the world's fifth- or fourth-largest field," he was quoted as saying.

"Production at South Iolotan-Osman can be built up gradually to 70 billion cubic metres (bcm) a year."

Turkmenistan, which produces about 70-80 bcm of gas annually, says its total reserves exceed 20 trillion cubic metres (tcm) -- much more than the 2.9 tcm estimated by BP (BP.L) in its annual statistical review.

The world's top gas producer, Russia, has 47.65 tcm of gas reserves and Iran has 28.13 tcm.

Gillett did not say how many other fields his company would audit or when it would present a final report.

The Turkmen press also reported Annaguly Deryayev, Deputy Chief Executive of state oil firm Turkmenneft, had been named Oil and Gas Minister, filling a post vacant since August. (Reporting by Marat Gurt; Writing by Olzhas Auyezov)