AQA Geography AS Geopolitics of energy?

Hi, I'm doing the AQA Geography course, and I'm having a few problems to what we actually need for this geopolitics section.

Does anyone have any notes on this section that they are willing to share?

As I'm a bit confused to what we actually need. How many case studies are we expected to know? And how much detail should we know about OPEC acting as a cartel, instability in middle eastern countries and Russia?

We were told to research russia, but could anyone give a brief outline of what the situation in Russia is? As I've tried searching, but I think that either I'm going into too much detail, or it is irrelevant. :/

Thanks.