Brent and WTI are the two main oil prices. Brent comes from the North Sea and is the global benchmark. WTI, short for West Texas Intermediate, is the main US price.
They usually move together, but Brent normally costs a few dollars more. Because Brent reflects oil shipped around the world, it reacts more to events in the Gulf and Europe. WTI reacts more to US storage and production.
Gulf crude is often priced in relation to these benchmarks, which is one reason Brent matters so much to the region.