This much-needed rebound pushes the busy port’s total residual fuel oil stocks closer to 19 million barrels. KeywaysInventories climb higher: Singapore’s residual fuel oil stocks grew by nine percent in July, nearing 19 million barrels. Singapore’s residual fuel oil stocks grew by nine percent in July, nearing 19 million barrels. According to Enterprise Singapore data, net fuel oil imports into the city-state skyrocketed by a stunning 77 percent in July. Brazil led the pack by providing a solid 16 percent of the total fuel oil imports for the month.