Iraq is preparing to upgrade the way it markets and exports oil from Basra in an effort to maximize revenues and combat a crippling financial crisis.The country has typically sold a single grade of crude, “Basra Light,” from all of its southern export outlets. But now Iraq is planning to market a second grade, “Basra Heavy,” which will allow the country to sell oil from more fields without compromising the quality of most exports.”We announced that we will sell two [grades],” said Fala…