Refiners retool for heavy oil

Oil companies are retooling their refineries to improve the processing of heavy crude, the cheapest grade of unrefined oil.

Price gaps are widening among the three basic grades. West Texas Intermediate Crude, a light oil, costs about $10 a barrel more than Dubai Crude, a medium oil. In January 2002, the difference was only $1. Heavy crude is about $5 cheaper than medium.