Hardcore oil/gal explorations can be real tough in harsh climates. 5 years of work experience is ideal for an executive MBA. Since you don't want to switch careers and are sure that you want to continue in the energy field, a one year course is what you should be looking to do. It would also be a whole lot cheaper than the traditional 2 year MBA.
It's good that you want to work in Europe but I would suggest you start trying to pick up native languages of the places you want to go to ASAP.
Addressing your first question, as far as your extra curricular activities go, the adcoms [admission committees] basically want to see if you are genuine. You seem to have varied ECs It doesn't have to be social work, it could be playing basketball for a club or even teaching they want to see if you are consistent. So pick anything and do it at least once a week. If you're unable to find time [a couple of hours a week] then the ad-coms see it as a lack of time management. It's good that you are preparing for your GMAT but try and sneak some time out for other stuff as well. To show consistency, you could maybe make a video for your company or continue serving as a PR co-ordinator..
The second, your strength would definitely lie in the fact that you have had good global exposure weakness that I see, from what ever little information I currently see about you, is your ability to manage time!
Hope this helps. Here's an article i bumped into for further reading.
Code:
h tt p : // www . find-mba. com / article / 314 / can-an-mba-spark-a-career-in-the-energy-industry
Take the spaces out