The Brent/WTI spread has historically ranged between $4/bbl and $8/bbl, but it can expand or contract based on factors related to U.S. and international supply and demand conditions. For example, the Brent/WTI spread hit nearly $14/bbl in April 2011 when protests sparked market fears of significant oil supply disruptions in the Middle East.

Oil prices rose about 1% on Friday, extending their rally and putting crude on course for a weekly gain on the back of output disruption in the U.S. Gulf of Mexico after Hurricane Francine forced the evacuation of production platforms.

The weakness in oil prices is due mainly to the potential inventory buildup in the oil market and the expected interest rate cut by the US Federal Reserve (Fed).

WTI oil has an American Petroleum Institute gravity of 39.6 degrees, considered “light.” WTI also has a sulfur content of just 0.24%, making it very “sweet.” WTI crude oil is typically the benchmark for U.S. oil prices in the trading world.