German company Wintershall has signed with Gazprom a preliminary agreement to acquire 15% of the South Stream pipeline.

This development gives a significant boost to the project, ahead of Russian PM Vladimir Putin's visit to Serbia and Slovenia to negotiate on it.

Over the previous months, there have been repeated reports that the German company, the largest producer of oil and gas in Germany, and owned by BASF, will be joining.

Russian PM Vladimir Putin expressed strong satisfaction about the deal, saying it is a "sign of stability" for the project.

Winteshall is expected to invest some EUR 2 M in South Stream.

Apart from Gazprom, the South Stream natural gas pipeline also features Italian company ENI. French EDF are expected to join later in 2011.

The South Stream project is aimed at strengthening the European energy security. It is the key project in the diversification strategy for gas supply routes to the EU. The South Stream gas pipeline will ensure a direct connection between hydrocarbons suppliers and consumers thus raising significantly the energy supply security on the entire European continent.