There are 3-4 rounds for the interview process. The first round includes CV screening after the submission of the application. After that, BP will request you to take an online assessment test, similar to what most banks expect you to complete. Thereafter, there will be a trading game whereby you will be asked to trade oil for a period of 3 months, and you will have to remember and provide certain specific details midway though the simulation like your profit/loss account, your current position, the bid-ask spread etc. After this stage, you will go through an interview with the specific department people that you applied for. Questions vary from background information, to technicals skills that you possess.