The previous stop on our tour of the world's key oil and gas production venues took us to South America, especially Venezuela and Brazil. We'll now find ourselves in Sub-Saharan Africa, with such important stops as Nigeria and Angola. We'll save northern Africa, with such producing nations as Algeria, Libya, and, to a lesser degree, Egypt, for later.

Once just a short hop
There was a time when traveling from, say, Brazil to Angola wouldn't have involved an especially lengthy journey. Indeed, about 200 million years ago, or when yours truly was but a wee lad, Africa and South America were each contained in a single supercontinent. By looking at a globe or a world map you'll notice that today the two continents' respective coastal features indicate that they once were firmly joined, only to be separated over time by the earth's plate tectonics.

That phenomenon is more than a relatively meaningless geographic tidbit. Rather, its importance for the world of oil lies in the respective latitudes of Brazil's Santos Basin and Angola's Cuanza Basin. They're virtually the same.

An invigorating new discovery
And so in just the past couple of years, geologists and geophysicists -- dedicated extrapolators all -- have taken the lessons learned from the sizable oil discoveries made in Brazil's pre-salt zone during the past five years to gain increased confidence that a remarkably similar pre-salt formation in the Cuanza also just might be hiding meaningful amounts of oil. Eureka! While exploratory looks into Angola's pre-salt only began in earnest a year ago, it appears that the formations there could mirror those in the Santos Basin.

In looking at Sub-Saharan Africa, we could theoretically traipse through Equatorial Guinea, Cameroon, and the Ivory Coast, all of which generate varying amounts of production. However, we'll limit our tour to Nigeria and Angola, by far the two biggest producers in that portion of the continent.

Nigeria: The largest oil producer in Africa, Nigeria cranked out a daily average of 2.13 million barrels of oil a day last year, down from a peak of 2.63 million daily barrels in 2005. A member of OPEC since 1971, the country's southern coast runs along the Gulf of Guinea, facilitating both onshore and offshore production. However, the lion's share of the oil industry is located in the delta of the Niger River, which flows into the gulf.

The country's proven oil reserves total about 37.2 billion barrels of light, sweet crude. And while it has a limited infrastructure for the development of natural gas, its reserves of that fuel are tops in Africa.

Participation in the Nigerian energy industry -- by far the largest element in the country's economy -- involves many of the big Western oil companies, including Royal Dutch Shell (NYSE:RDS.B), France's Total (NYSE:TTE), and ExxonMobil (NYSE:XOM). Virtually all producers working in Nigeria have been plagued at one time or another by terroristic activities by members of the Movement for the Emancipation of the Niger Delta (MEND), which is made up of tribesmen indigenous to the delta, but who have typically been frozen out of energy-related jobs by those from other parts of the country who happen to hold more political clout.

Calming down
Incidents of attacks on production facilities have declined since late 2009. That was when amnesty was declared and the militants reached an accord with the government. Nevertheless, the country's decline in daily crude output during the past half-dozen years is largely attributable to the activities of MEND.

Recently, some of the big companies working in Nigeria have been unloading portions of their holdings. Since July, Shell has announced a pair of sales to local Nigerian companies, in connection with the avowed objective of the country's government to increase participation in upstream activities among local operators. And earlier this month, China's Sinopec (NYSE:SHI) agreed to pay $2.5 billion to Total for a 20% stake in the offshore Usan field.

Angola: Long the site of active oil production, as I've already noted, Angola may have moved into a new era during just the past few months with the discovery of oil in the country's pre-salt. In February, for instance, Cobalt International Energy, which is largely owned by Goldman Sachs (NYSE:GS), announced a discovery in Bloc 21 of the Kwanza Basin deepwater. The find may produce as much as 20,000 barrels of oil per day. And for perhaps obvious reasons, Brazil's Petrobras (NYSE:PBR) also is involved in Angola's pre-salt.

Given the apparent potential of the zone, the country's current production of up to 1.66 million barrels a day and its reserves, which constitute an estimated 9.5 billion barrels, are both likely to increase, perhaps dramatically. Conventional oil operations in Angola began in 1915, with the drilling of the country's first exploratory well. Much of the historic activities in Angola have involved Chevron (NYSE:CVX), which remains the largest foreign oil industry employer.

Oil clearly is transforming Angola, which joined OPEC in 2007. As The New York Times noted in an article last year relating the country's pre-salt potential to prior discoveries in Brazil, "Luanda, Angola's capital, has become a testament to what oil can bring. A few years ago the city was just emerging from decades of civil war (which raged from 1975 to 2002). Now the streets are filled with cars, and for ex-pats, rents can be more expensive than in London."

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.