Kazakhstan's largest oilfield cuts output by fifth since Oct. 26, sources say

MOSCOW, Nov 13 (Reuters) - Kazakhstan's biggest oil field Tengiz, operated by U.S. major Chevron , has reduced oil output by around 21% on average since Oct. 26 to 62,600 metric tons per day, or 496,200 barrels per day, three industry sources told Reuters on Wednesday.

The Central Asian nation, which relies on Tengiz and two other major fields, Karachaganak and Kashagan, for most of its production, is subject to output targets as a member of OPEC+, an alliance of OPEC and other top producers led by Russia.

The production decline may help Kazakhstan comply with its output quota under an agreement with the OPEC+ group.

One of the sources said production has declined due to maintenance at the field. The operator of Tengiz did not immediately respond to a request for comment.

Tengiz boosted oil output to a record high in early October to 699,000 bpd from 687,000 bpd in September, when output increased by 30% from August after the completion of maintenance.

Chevron and its partners plan to expand output at the Tengiz project to 850,000 bpd in the first half of 2025. Expansion costs at the project stand at around $49 billion.

Chevron owns a 50% stake in the venture. Exxon Mobil controls 25%, KazMunayGaz has a 20% stake, and Russia's Lukoil owns 5%.

Kazakhstan's average daily oil output in October was down 20% from September, complying with the country's OPEC+ quota, according to Reuters calculations.

The output was about 150,000-185,000 bpd lower than the country's OPEC+ quota of 1.468 bpd, depending on the ratio used for the conversion of tons into barrels.

(Reporting by Reuters; Editing by Sharon Singleton)