Anadarko Petroleum Corp. said it was considering Occidental Petroleum Corp.’s $38 billion offer, weeks after agreeing to be taken over by Chevron Corp. for about $33 billion, raising the likelihood of a bidding war for assets in the heart of the U.S. fracking boom. The declaration puts the onus on Chevron to raise its price or walk away from its deal for Anadarko, whose acreage in the Permian Basin of West Texas and New Mexico is coveted by both Chevron and Occidental as a path to further expansion. …