Crude prices dipped below $30 a barrel this week for the first time in years. But for many producers, $30 oil already is a thing of the past. Most barrels of oil sold globally garner less than benchmark prices because they are deemed lower quality, or because buyers incur higher shipping costs. While discounts exist in times of high prices, too, they are more painful for producers when prices are low. A basket of crude oils sold by the 13 members of the Organization of the Petroleum Exporting Countries fell Wednesday to $25.69 a barrel. Oman crude-oil futures on the Dubai Mercantile Exchange, a benchmark for crude exports from the Middle East to Asia, fell to $25.88 a barrel Wednesday. And some of the cheapest crude oil in the world, in Canada, costs less than $15. These ultralow prices already are forcing producers to pile on spending cuts and […]