By Arathy Somasekhar

HOUSTON(Reuters) - Price differences between U.S. light and heavy crude oil grades have been widening, pricing data showed, as refiners around the world have been snapping up less-dense crude grades for more gasoline production. 

As summer begins, sky-high demand and profits from motor fuels production has encouraged global refiners to buy lighter barrels. Since Russia's invasion of Ukraine, more Russian Urals crude has been moving to Asia as more U.S. light-sweet heads to Europe. 

Those changes, combined with ultra high prices for natural gas used in refining, have favored, easier-to-process lighter grades. Prices for U.S. natural gas have more than doubled this year. 

Gasoline-friendly light sweet WTI Midland priced at East Houston, called MEH, has averaged a $1.40 per barrel premium to U.S. West Texas Intermediate (WTI), compared with a 96-cent premium in the year-ago period, as exports to Europe climbed.