Repsol YPF chairman Antonio Brufau (L), CEO of British Petroleum Tony Hayward and Shell's Chief Executive Officer Jeroen van der Veer (R) talk after a plenary session during the 19th World Petroleum Congress in Madrid, June 30, 2008. The World Petroleum Congress, which is held every three years, will last until July 3. REUTERS/Susana Vera(SPAIN)