An end to sanctions on Iran has driven global crude futures to 12-year lows and brought sub-$20-a-barrel oil in sight, although for some producers that is already a painful reality. This unfortunate group sells some physical crude cargoes at prices that are closer to $10 a barrel, thanks to an abundance of the "sour" grades they produce and a consumer base that favors higher-quality "light" oils from other origins. (Graphic: reut.rs/1ZGAl0s) Producers of certain crudes from Mexico, Venezuela, Canada and Iraq are bracing for worse to come as Iran - now free of international sanctions - prepares to offload hefty ... (full story)