Applied online and received offer for interview about 6 weeks later. Arrived at the hotel they were using and had lunch, meeting the ten or so other geology candidates. We had a brief presentation about BP then proceeded to have one personal interview of 45 minutes and one technical interview of 90 minutes each. The personal interview was very standardised and competency based, they were particularly interested in team work. The technical interview started with a "story" where they gave you little bits of information about an area and you had to say what you would do to find out more, where you thought the oil would be etc. The story was then followed by interpretation of a seismic line. I hadn't done much before and even though I told them this they weren't very helpful. The technical interview would be hard to prepare for, they want to see the way you approach a problem rather than any preexisitng knowledge.