Venezuela sets minimum $500 mln premium for Carabobo

CARACAS, July 2 (Reuters) - Venezuela will demand that oil companies pay an increased premium of between $500 million and $1 billion to participate in the development of the Carabobo oil block in the OPEC nation's giant Orinoco heavy crude belt.

The premium is to be paid by consortiums that win a tender round, the results of which are expected to be announced on August 14, and worsens already tough conditions for companies hoping to build upgraders to extract the region's tar-like oil.

Among the firms expected to participate in the tender are Chevron (CVX.N), BP (BP.L), Statoil (STL.OL), Total (TOTF.PA), CNPC, Repsol (REP.MC) and Petrobras (PETR4.SA)

Other interested companies include Italy's Eni (ENI.MI), Mitsibushi (8058.T), Galp Energia (GALP.LS), Shell (RDSa.L) and Gazprom and Colombia's Ecopetrol ECO.CN.

According to a revised document on the Oil Ministry's website, the price will depend on the location of the blocks and how difficult it is to develop them. (Reporting by Marianna Parraga; Writing by Frank Jack Daniel; Editing by Christian Wiessner)