The U.S. Strategic Petroleum Reserve held just 283 million barrels of oil at the end of September, according to Reuters, the lowest level since October 1982, back when the reserve was still being filled for the first time. It's a scary-looking number, and most of the coverage has treated it that way. But the barrel count is the easy part of this story. Oil came out of those Gulf Coast salt caverns fast, because that's exactly what the system was built to do. Getting it back in is slower, more expensive and more dependent on things nobody controls.…