Crude oil trades in U.S. dollars. See chart: https://www.marketwatch.com/investing/index/dxy/charts
In early September the U.S. dollar Index (DXY) dipped to 91.35. Today it is at 93.87. When the dollar goes up, oil price goes down (most of the time).
Just giving you another variable to check when you are trying to understand why oil prices move.
U.S. Dollar Index
U.S. Dollar Index
Dan Steffens
Energy Prospectus Group
Energy Prospectus Group