ANKARA, May 5 (Reuters) - Projected investment in the Nabucco gas pipeline has been revised up to 12-15 billion euros ($18-22 billion) from 7.9 billion euros, sources close to the matter in Turkey told Reuters.
Nabucco plan intends to bring up to 31 billion cubic metres of gas annually from the Caspian region to an Austrian hub via Turkey and the Balkans. It aims to open in 2015.
Some partners investing in Nabucco are opposed to meeting the revised sum and seek a cost reassessment, the sources said.
The investment decision could be delayed until 2012, given the increased costs and supply problems, the sources added. ($1=.6726 Euro) (Reporting by Orhan Coskun)