MOSCOW, July 23 (Reuters) - Black Sea CPC Blend oil

exports via the Caspian Pipeline Consortium (CPC) pipeline

system are set to fall to about 4.9 million metric tons in

August from the 5.4 million planned for July, two sources

familiar with the plan said on Tuesday.

On a daily basis CPC Blend oil exports will decline by 9.3%

in August from July plan, Reuters calculations showed.

Chevron ( CVX )-led Tengizchevroil plans maintenance on its giant

Tengiz oil field next month, which will lead to lower output and

a drop in supplies to the CPC system.

TCO is the largest oil exporter via the CPC pipeline system.

CPC does not comment on export plans via its system.

Chevron ( CVX ) holds a 50% stake in TCO, Exxon Mobil ( XOM ) owns

25%, Kazakh state firm Kazmunaigas holds 20% and 5%

belongs to Russia's Lukoil.