Eyton, part of Chief Executive Officer Bernard Looney's leadership team, joined BP 40 years ago. He will continue to act in a technical advisory capacity for the remainder of the year, according to the memo.

Russell, currently head of procurement and supply chains, joined BP 16 years ago. She will become the sixth woman on Looney's 12-strong leadership team.

Last month, Geoff Morrell, the company's head of communications and advocacy and leadership team member, also stepped down to join Walt Disney as chief corporate affairs officer.

Morrell's replacement in BP has yet to be announced.

(Reporting by Ron Bousso;Editing by Elaine Hardcastle)

By Ron Bousso