The initial interview, which occurred at my university, consisted of two 1:1 interviews with senior-level employees. Both interviewers were very laid-back and conversational. They brought a copy of my resume, and we walked through each bullet point. It seemed as if they were looking more for a cultural fit, rather than examining my academic or professional background (I suspect that they had already approved my credentials and were just making sure that I was "normal"). I received an invitation for the second-round interviews within two weeks. This round occurred at the Downstream headquarters located in Houston, TX. The interviews consisted of four 1:1 interviews with senior-level employees and lunch in between the interviews with new hires. Again, the interviewers were very conversational, and the majority of the 45-minute interviews involved me asking questions of the interviewers (they want to gauge your interest in working for the company). Remember to ask a lot of questions! I received an offer a couple of days after the interviews. During my internship, I found out that the screening process for the interviews is very comprehensive during the first round, followed by a moderate to high offer rate (60%+) for second-round interviews. Of the 5 or 6 candidates that I interviewed with during the second-round, 4 (including myself) accepted the offer.