What a widening or narrowing balance means
The U.S. became a net exporter of petroleum. Crude plus products. In late 2019 for the first time since the 1940s, and net petroleum imports have been negative most weeks since. Occasional net-import weeks still appear (for example around 2023). A negative reading is the structural normal now; the interesting signal is how far it goes. Deep net-export readings mean the refining and production system is pushing large volumes to world markets; swings back toward net imports flag weaker export capacity or stronger import need.