WeeklyBattle lines drawn as Oxy bids for AnadarkoUS giant offers $57 billion as it looks to beat Chevron in race to take over independentParty crasher: Occidental Petroleum is attempting to rain on Chevron’s parade after coming in with a $57 billion counterbid for Anadarko Petroleum, which has already turned its back on numerous Oxy offersFoto: RYTIS DAUKANTAS/UPSTREAMEoin O'CinneideLondon