Offshore drillers like Ensco ( ESV ), Seadrill ( SDRL ), Rowan ( RDC ), Diamond Offshore Drilling ( DO ), and Transocean ( RIG ) have caught a bid today as markets rally , oil rebounds , and Ensco was on the receiving end of an upgrade. Susquehanna's Charles Minervino and team explain why they upgraded Ensco to Neutral from Negative: