U.S. onshore operator American Energy Partners LP (AELP) has hired Scott D. Sachs as senior geoscience executive adviser, James C. Johnson as senior marketing and midstream executive and Traci D. Cook as chief accounting officer. All three previously worked for AELP founder Aubrey McClendon when he was CEO of Chesapeake Energy Corp. Sachs, 54, had been vice president of geoscience from 2005 to 2014 and spent 18 years at Marathon Oil Co. Johnson, 57, was Chesapeake senior vice president of marketing for 18 years and, beginning in 2000, was president of Chesapeake Energy Marketing Inc. Cook, 50, was a Chesapeake executive for 19 years and since 2006 had been vice president and division controller of financial analysis and reporting.