Occidental Petroleum Corp. (Oxy) has promoted Executive Vice President Vicki Hollub to senior executive vice president and president of Oxy Oil & Gas. She is to become CEO when Stephen Chazen retires; his retirement date has not been announced. A mineral engineering graduate from the University of Alabama with nearly 35 years of industry experience, Hollub began her career in 1981 with Cities Service, a year before it was acquired by Oxy.