The three biggest U.S. oil explorers to post earnings so far are bracing for another year of deep spending cuts as the slump in energy markets shows no signs of abating. Hess Corp, Occidental Petroleum Corp. and Anadarko Petroleum Corp., the largest producer in Colorado , reported third-quarter losses as free-falling crude and natural gas prices choked cash flow, halted drilling projects and exacted billions of dollars in writedowns as once- prized oil fields dwindled in value.