High-quality: WTI Is taken into account a "gentle sweet" crude oil, which happens to be much easier to refine, when Brent is usually a combination of crude oils, like equally "mild sweet" and "large sour" grades. Screening is by references that POs check with each other for, not by printed https://maps.app.goo.gl/VhAGTRCDGTuVhHJa8