Nigeria one of the six (6) countries that will be doomed if oil prices continue to fall.

For governments in oil-exporting countries to meet their spending commitments they need oil to remain above a certain price. With oil prices under $87 a barrel, countries that rely on high oil prices, including Venezuela, Russia, and Saudi Arabia, may have a reason to be concerned.

If the price remains depressed, these countries will either be forced to borrow more to cover the shortfall in oil tax revenues or backtrack on spending promises. Cutting back on spending pledges would be highly embarrassing for these countries' governments.

Saudi Arabia is prepared to sell oil as low as $80 for two years in order to curb competition from the United States, but how far Saudi Arabia can let prices fall without incurring too much domestic pain? In September, the International Monetary Fund warned that Saudi Arabia would run a deficit of roughly 1.4 percent in 2015.

The problem for the Organization of the Petroleum Exporting Countries is that it may no longer be able to control prices (as it has in the past) to avoid these problems.

Previously, OPEC members would agree to cut oil production if falling prices posed a threat. That may now have changed because of the shale oil boom in the US, which has dramatically increased supply.

Falling prices are of particular concern to Russia. Russia needs high oil prices to buoy its economy. The country has seen its economic performance slow under the weight of sanctions over Ukraine and weakening domestic demand. The problem is that Russia's latest budget requires oil prices to average at least $100 a barrel in order to cover the government's spending promises. The government already needs to borrow around$7 billion from foreign investors next year and as much as 1.1 trillion rubles ($27.2 billion) from domestic investors

The Venezuelan government leans heavily on oil revenue to fund spending on housing projects, community organizing and other social programs and now oil production is falling at a time when the country desperately needs cash. Venezuela literally needs the price of oil to double to keep its house in fiscal order.

Nigeria would be the worst-hit African oil exporter if this drop in oil persists should persist. About 75 percent of the Nigerian government’s revenue comes from taxes on the oil and gas sector and with much of the government’s revenue funded by oil, funds for its capital and recurrent spending is heavily reliant on the income from the commodity. A decrease would be devastating.

Bahrain, with an estimated break-even price of $116.40 per barrel next year, is already running budget deficits and would see these swell, reports Reuters.

Oman is expected to face a break-even price of $107.50, which could push it back to the international debt market next year for the first time since 1997, reports Reuters.

This chart shows the price per barrel that the six most exposed countries need to meet their national budgets. Remember, the price Friday is a piffling $87. (Business Insider)