Kukes , who became the CEO of Yukos , was already an experienced oil executive .
Yukos moved quickly to replace Khodorkovsky with a Russian - born U.S. citizen , Simon Kukes .
Simon Kukes , who became the CEO of Yukos , was already an experienced oil executive .
Yukos moved quickly to replace Khodorkovsky with a Russian - born U.S. citizen , Simon Kukes .