This petrodollar conspiracy is baffling.
Countries don't hold dollars primarily to buy oil.
The oil and gas industry is only about 4.6% to 6.5% of the global economy.
Countries hold reserve currencies to manage the exchange rate of their currency. Petrodollar conspiracists would be well served by learning about foreign exchange reserves.
See: https://en.wikipedia.org/wiki/Foreign-exchange_reserves
And in any case, only 65% of foreign currency reserves are in the USD.
Furthermore, research shows that being the world's primary reserve currency affords the United States negligible advantage: 0.3 to 0.5 percent of US GDP in a normal year.
See: http://www.mckinsey.com/insights/economic_studies/an_exorbit...
Compare that to the costs of "deposing the leader of an oil producing country": $6 trillion for the Iraq war or about 36% of GDP
See: http://www.reuters.com/article/us-iraq-war-anniversary-idUSB...