Orphaned wells in the United States

Though different jurisdictions have varying criteria for what exactly qualifies as an orphaned or abandoned oil well, generally speaking, an oil well is considered abandoned when it has been permanently taken out of production. Similarly, orphaned wells may have different legal definitions across different jurisdictions, but can be thought of as wells whose legal owner it is not possible to determine.

Source: Wikipedia — Orphaned wells in the United States (CC BY-SA 4.0)