Posted: 01 Jul 2012 09:08 AM PDTExxonMobil confirms that it has filed to bid on a group of Afghanistan oilfields containing an estimated 1 billion barrels of oil and gas. The tender deadline was yesterday to file an expression of interest. Company spokesman Alan Jeffers told me that the filing is among Exxon's global search for new hydrocarbon opportunities. The Exxon filing is surprising because until now the Afghan natural resource play, while rich, has been perceived as highly speculative and risky. By filing an expression of interest, Exxon at once validates the play.