The perpetual pendulum of crude traders worrying about the world swimming in oil on one end and worrying about supply shortages at the other swung decisively to the latter on Wednesday, with oil prices hitting a three week high due to the U.S. in the earlier session sanctioning a unit of Russia ‘s Rosneft . Rosneft is Venezuela ‘s main oil shipper, and analysts believe the sanction will seriously jeopardize the Bolivian republic’s ability to export crude. Reuters noted that the sanction will make it more difficult for Venezuela to export oil, particularly to countries such as China and India , however it will pose only a limited risk to Rosneft’s broader business. The new-found concern over Venezuela (whose output has already been marginalized by the U.S.) combined with more fighting in Libya that quashes hopes of ending a blockade of that country’s crude exports, caused Brent on Wednesday […]