Apache Corp. Executive Vice President Kregg Olson, who oversees corporate reservoir engineering and has worked for the company for 26 years, is retiring effective Aug. 1. Senior Vice President Dave Pursell, now in charge of planning and market fundamentals, is to assume responsibility for reservoir engineering when Olson retires. Before joining Apache in early 2018, Pursell was managing director of investment banking for Tudor, Pickering, Holt & Co. He previously was head of macro research and a founder of Pickering Energy Partners Inc. and also has been director of upstream research at Simmons & Co. International. Pursell has a bachelor of science and a master of science in petroleum engineering from Texas A&M University.

BP plc has tapped Helge Lund, 55, formerly chief at BG Group plc, to succeed Carl-Henric Svanberg as chairman effective Jan. 1. Lund is joining the board as chairman designate and nonexecutive director on Sept. 1. Lund, who also is chairman of Novo Nordisk AS in Denmark, plans to stand down as a director at Schlumberger Ltd. Group CEO Bob Dudley noted that Svanberg had guided the company through BP’s “darkest days,” referring to the Macondo tragedy, “and into this period of growth and modernization.” Lund served as CEO of BG from 2015 to 2016, when the company merged with Royal Dutch Shell plc. He joined BG from Statoil ASA where he served as president and CEO for 10 years. Prior to Statoil, he was president and CEO of Aker Kvaerner. Lund has a business degree from the Norwegian School of Economics and Business Administration and a masters degree from INSEAD in France.