"We shouldn't put domestic producers at a competitive disadvantage by limiting the available markets," Ryan Lance, CEO of Texas-based ConocoPhillips, told the U.S. Chamber of Commerce on Tuesday. Scott Sheffield, CEO of Pioneer Natural Resources, also based in Texas, was making the same push Tuesday in front of the House Subcommittee on Energy and Power, arguing the industry's struggles with low oil prices are worsened because companies aren't allowed to ship American crude oil to foreign nations.