Chevron Corporation is one of the largest integrated energy companies in the world. The company is engaged in every aspect of the oil and natural gas industry, which includes exploration and production; refining, marketing and transportation; chemicals manufacturing and sales; and power generation. Chevron also develops and commercializes advanced energy technologies, such as core hydrocarbon technologies, a global digital infrastructure and information technology. Its business development portfolio includes hydrogen infrastructure, advanced battery systems, nano-materials and renewable energy applications. David J. O'Reilly has been the chief executive officer of Chevron for more than six years. He has been with the petroleum and chemical company for over 38 years. O Reilly earned a BSChE degree from the University of Dublin. Chevron Corporation maintains its headquarters in San Ramon, Calif., and it conducts business in approximately 180 countries.