Iran is making “good progress” on its first concerted oil drilling operation in the Caspian Sea in 30 years, a senior energy source who works closely with the Islamic Republic’s Petroleum Ministry exclusively told OilPrice.com over the weekend. “The signs are promising in the block [‘18’ in the Roudsar formation from 70-metre waters around 15 kilometres from the northern Iranian coastline] and if it continues to be so then there is great potential there,” he said. “Official estimates are that this…