Heres some facts about Oil The data about Oil inventories is always plus or minus millions of barrels but have you ever wonder just how big their storage units are? Heres a look at China and the US. China has 1.5 Billion barrels of storage capacity while the US has about 1.3 Billion barrels and global crude storage is 4.2 Billion barrels leaving another 1.2 Billion in effective spare capacity. So even though their concerned about using up 3 Million barrels we're far from being empty.
Here's a look at countries and their inground Oil reserves, the last data was released in 2016
https://www.worldometers.info/oil/oil-reserves-by-country/