Go make yourself busy by surfing youtube on how to make a good platform from paper. In general, bigger base, the heavier the base, the stronger the structure can hold. Astro even have a documentary on this.
But don't get too carried away thinking that analytical skills are the only thing that they look for. You need to prepare yourself with the ability to dommunicate, interact and cooperate with your team members. Make sure you shine during the team discussion but not too overshine leaving no space to your team mate. But one thing is clear, passiveness is not an option. Speak out as many ideas as you can, and if you have some opportunity to help your team members, help them or even guide them. That will be a good mark for you.
If you pass that schlumberger second interview, don't be too confident that you might get the job, 3rd and 4th stage interviews are waiting for you. But from what I've heard, the second interview is mainly about reasoning, arguing and communication skills. So focus on that. If your team loses during the project, it is not the end of the world. If you shine well in your interpersonal and teamworking skills, there is still hope for you.
One thing to bear in mind, if you are selected as team members, take it and don't reject it. It will be a big plus if your team wins. Good luck and have fun during the interview :)
