MOSCOW, June 17. /ITAR-TASS/. The consortium building gas pipeline South Stream will keep in effect plans to build an offshore part of the pipe even in case of European Commission’s (EC) negative solution on the project in Bulgaria, Chairman of Wintershall Board of Executive Directors Rainer Seele said at the 21st World Petroleum Congress in the Russian capital on Tuesday, adding that the largest German energy giant does not mull possible withdrawal from the consortium.