It seems like Big Oil can weather most economic storms. In a difficult fourth quarter, with flat oil prices and a shale boom in the U.S. keeping natural gas in place, with the world’s largest economy contracting and China slowing, Exxon Mobil and Chevron handily beat profit expectations, despite mediocre revenue numbers and decent production figures. With mixed upstream results, both U.S. oil behemoths derived downstream strength from previously troubling refining margins coupled with asset sales; and, as has been the case for some time, chemicals continue to deliver.