Before the most recent round of sanctions went into effect three years ago, Iran was able to sell oil to 21 countries. By mid-2012, that was down to six: China, India, Japan, South Korea, Taiwan, and Turkey. Rather than immediately pull back on production, and risk damaging oil wells by slowing them down, Iran decided to store its excess crude. As it scrambled to build onshore tanks, the government loaded millions of barrels onto its suddenly out-of-work fleet of crude-carrying vessels. The Iranians eventually reduced their oil output by about a third, to a low of 2.5 million barrels a day in mid-2013, according to data compiled by Bloomberg. As exports fell to 1 million to 1.5 million barrels a day, Iran kept filling its tankers with oil it […]