Chevron has signed a preliminary deal with Iraq’s Basra Oil Company to discuss the potential sale of the giant Iraqi oilfield West Qurna 2, formerly operated by Russia’s Lukoil, to the U.S. supermajor. The preliminary agreement, signed on Monday, allows exchange of confidential data and could lead to exclusive talks for Chevron to take over West Qurna 2, whose operations were recently transferred to the Iraqi state-owned company. The preliminary agreements also establish an outline for a period of exclusive negotiations,…