GEORGETOWN, Guyana — Guyana is a vast, watery wilderness with only three paved highways. There are a few dirt roads between villages that sit on stilts along rivers snaking through the rain forest. Children in remote areas go to school in dugout canoes, and play naked in the muggy heat.

Hugging the coast are musty clapboard towns like Georgetown, the capital, which seems forgotten by time, honeycombed with canals first built by Dutch settlers and African slaves. The power grid is so unreliable that blackouts are a regular plague in the cities, while in much of the countryside there is no electricity at all.

Such is the unlikely setting for the world’s next big oil boom.

In the last three years, ExxonMobil has drilled eight gushing discovery wells offshore. With the potential to generate nearly $20 billion in oil revenue annually by the end of the next decade , roughly equivalent to the revenues of the much-larger Colombia, there could be enough bounty to lift the lives of almost every Guyanese.

If all goes well, one of the poorest countries in South America could become one of the wealthiest. Suddenly the talk of Georgetown is a proposed sovereign wealth fund to manage all the money, as if this were a Persian Gulf sheikhdom.