Crude oil is produced, stored, refined, and moved. The spot price is the price of a barrel at a point in that chain on a day. Inventories are a count of what is in storage. They are published on their own schedule, by agencies that count them.
A price can fall while inventories fall, or rise while they rise. The pair is interesting when you have both numbers from documents. It is gossip when you have the price and a theory about the tanks.