The Caspian Pipeline Consortiums shareholders have approved of an expansion to double the pipelines capacity.
The pipeline transports oil from Kazakhstan to the Black Sea.
CPC plans to increase the pipelines capacity of the 1,5800 kilometre pipeline to 67 million tonnes a year by 2014.
There will be an investment of around $4.5 billion (3.1 billion) into the pipeline.
Last year the pipeline transported 31.57 million tonnes of crude oil to Russias Black Sea port of Novorossiysk from Tengiz field in Kazakhstan.