Saudi oil revenue has already sunk below government expenditures[1]. The just-announced 2016 budget has a deficit of $87 billion[2]. That's 7 years to go until the reserves are gone.

And how much does the House of Saud hand out to its citizens to keep things calm and orderly? What happens when that money starts to dry up?

[1] http://www.wsj.com/articles/new-saudi-budget-expected-to-be-...

[2] http://english.alarabiya.net/en/special-reports/saudi-budget...