With Keystone down and Exxon under investigation, it's been a tough week for the oil business

On Thursday, word came that ExxonMobil is being investigated for possibly misleading shareholders on the risks climate change poses to its business. On Friday, President Obama killed the Keystone XL oil pipeline to the US from Canada, citing the threat of climate change from burning fossil fuels. The oil business has seen worse weeks, but perhaps not many.