Oil prices extended their recent recovery rally and rose more than 1% on Thursday as a large cut in U.S. interest rates and declining global stockpiles helped offset some of the demand concerns arising from weak consumption in China.

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.