NEW YORK (Bloomberg) -- U.S. refiners aren’t just buying crude to turn into gasoline and diesel -- they’re competing with producers and traders to export it.

Marathon Petroleum Corp. and Phillips 66 -- two of the three biggest U.S. independent fuelmakers -- are getting in on the shale export boom. Both are part owners of existing pipelines and new ones being built from the Permian Basin to the Gulf Coast.

Marathon Petroleum Corp.’s CEO Gary Heminger traveled to Singapore and South Korea two weeks ago looking to line up potential customers for American crude, he said in an interview at the American Fuel & Petrochemical Manufacturers conference in San Antonio.

In addition to the Gray Oak pipeline to Corpus Christi, Texas, which should be completed by the end of the year, Marathon has an interest in Capline, which will be reversed to carry crude from the Midwest down to the New Orleans area, from where it can be exported via the Louisiana Offshore Oil Port.

Phillips 66 shipped Bakken oil from North Dakota to Mexico late last year, beating out trading houses and and producers to supply Petroleos Mexicanos with its first U.S. crude cargo.