I was contacted by student services at my university telling me that Valero was interested in interviewing me for a possible internship over the summer and a possible job offer. They gave me a week to prepare for the interview, and it consisted of 2 senior engineers, one which worked closely with human resources and did the actual hiring. Questions pertain closely to demonstrating examples of past job experiences that led to success through creativity. They want details and observe body language and level of motivation. They made it that apparent, although I'd say this is very much likely an interview tailored towards students with no prior experience in the engineering field.