US President Donald Trump’s trade wars and sanctions are tightening the market for heavy crude, boosting prices for the sludgy oil and raising costs for the largest American refining center.

Canadian heavy crude is trading at the smallest discount to benchmark US oil in almost four years after a rush of sales to ...

for example, was built in the late ... Many refineries need a heavier grade of crude oil — one that is more viscous than the light sweet crudes produced from U.S. shale — to “maximize ...

The blending problem presented in the introduction is a good example ... oil into finished oil products involves a distillation process that splits crude into various streams. Suppose that there are ...