According to Wikipedia we produce about 7 million barrels of oil each day and import another 12 million, for total consumption of 19 million barrels per day (that's fucking mind boggling... though I just checked and a single supertanker can carry 2 million barrels, so that's not all that many tankers, not even counting pipelines). The oil that we aren't working is because at current prices it's not economically viable to work it, not because we want to hoard it (though we do have the Strategic Petroleum Reserve, but that only holds 36 days' worth of oil, not exactly a long term fallback).
*Edit* - Just saw in that same article I linked that maximum draw from the Strategic Petroleum Reserve is 4.4 million barrels a day, so it can only replace about 1/3 of our daily imports. Though it does mean that even though it only has 36 days' worth of our total consumption, it would actually take 158 days to completely drain it. Still not a long term solution, it's intended more as a supplement for temporary supply disruptions.