WEST Perth-based petroleum explorer ARC Energy Ltd’s plans to acquire the Wandoo Petroleum Pty Ltd Australian portfolio for $380 million have suffered a setback, with Canada-based Vermilion Oil & Gas exercising its pre-emptive rights to a major asset. Vermilion held a pre-emptive right to Wandoo’s 40 per cent stake in the Wandoo oil field, in the offshore Carnarvon Basin, and will now acquire that right under the same terms. The total cost of the acquisition will now be, according to ARC, around $229 million, down around $151 million on its previous announcement. - Andrew Hobbs