4 rounds:
1) very technical interview, incl. stock pitch, key drivers of E&P model, how to value an E&P company, how to estimate the value that the new oil production will add to the company, questions about direct modeling experience, near-term investment recommendations, etc.
2) excel case study + presentation: some key information for the case study was missing, the case study is very ambiguous, what is more, it is NOT on oil & gas, but rather on chilled water and steam system of a building as well as a solar park project! It took me 2 days to create it all. I am not sure if they themselves are aware of the shortcomings of their case study. I also do not know if they understand its complexity.
3) another very technical interview. Similar questions to the 1st round. The key however was the ability to talk about the case study. They want you to confidently talk on the topic that you have little idea about. That tells me that this is probably the skill that you need to have for this job = use your confidence to compensate for the lack of knowledge or understanding. Some of the "right" answers on case study clearly contradict the case study description.
4) another interview with top management (I did not get to this one).