Journal of Petroleum Science and Engineering

Independent positive signals — not a single “predatory/legitimate” verdict, but a converging picture.

• DOAJ—
  No data
  doaj.org
• OAK list—
  No data
  OAK
• Valid ISSN✓
  Present
  ISSN

This is an information label, not an official ruling. A missing signal is not a penalty — a regional journal may simply not be in DOAJ.