The Permian property would be the most highly sought after and could attract bids from Royal Dutch Shell Plc or Anadarko Petroleum Corp., both of whom have drilling leases nearby, Macquarie Group Ltd. said in July. Shell declined to comment at the time. Anadarko Chief Financial Officer Robert Gwin has called the two companies' assets "very natural fits." But Texas-based Anadarko has since committed $2.5 billion of its available cash to share buybacks, potentially complicated any bid for a BHP acquisition.