So what's next?
Although the prospects look bleak, Western firms are not completely locked out. Many state-owned oil companies will still cut deals with the big multinationals, just under tougher terms.
With an eye toward supplying their own growing economies, the state oil firms may be willing to give up reserves in their own country in exchange for concessions elsewhere, said David Hobbs, head of research at Cambridge Energy Research Associates.
And combining oil deals with other plans to develop a country's infrastructure -- like building ports or railroads -- is another way foreign forms can secure new contracts. "Increasingly, you seeing deals with bundled components," said Hobbs. "Resource holders are looking to use access as a way to get more economic development in the country."