Exxon would love to own more of its offshore development in Guyana or at least keep it out of Chevron's hands.ExxonMobil (XOM -0.64%) and Chevron (CVX 0.43%) are behemoths in the oil patch. The integrated oil giants have operations that span the globe and the entire oil sector value chain -- upstream, midstream, and downstream. While they're peers, they are also fiercely independent and competitive. They routinely benchmark their results against each other. Their competition isn't always friendly. The oil c ...