Most Venezuelan oil is a viscous black substance and is extremely difficult to process into usable fuel. Worthless, you might think. But it is precisely those properties that may make the raw material interesting for the American oil companies, says Bert Weckhuysen, professor of inorganic chemistry and catalysis at Utrecht University.
“When most people think of crude oil, they immediately think of black powder,” says Weckhuysen. “But it can have all kinds of colors. It varies from that syrupy dark black to a more liquid dark green or brown-orange.” What petroleum looks like depends on where you extract it. “For example, there is relatively pure light oil under the North Sea.”
Light oil is relatively easy to process into usable fuel such as gasoline. “A piece of cake“Weckhuysen calls that process. The oil in Venezuela is heavy and therefore requires a much more extensive process in the refinery to convert it into a usable fuel.
Sweet or sour
This has everything to do with the chemical composition of petroleum, which naturally contains all kinds of different types of molecules. Light oil contains relatively short chains of carbon and hydrogen atoms, while in heavy oil the chains are much longer and more complex. A refinery makes fuels such as gasoline or diesel from petroleum, by separating those oil molecules based on their chain length, or by breaking longer molecules into shorter, uniform pieces using chemical processes. That is why heavy oil is more difficult to process: the longer and more complex the chains, the more effort it takes to cut them to the right length.
But that is not the only “disadvantage” of oil from Venezuela, Weckhuysen continues. “Petroleum can also be sweet or sour. That’s a bit of a strange way to describe it, because no one tastes it anymore these days. It is of course poisonous. But in the early years of petroleum discoveries, people did and that’s how they noticed differences.” Venezuela has so-called “sour” oil, he explains, which contains more other chemical elements such as sulfur.
Such acidic oil poses an additional challenge for most refineries: “it is corrosive, it eats away at the refinery’s pipes and can cause it to function less and less well.” Because of all these bad properties, Venezuelan oil is a lot cheaper than, for example, light sweet oil from the North Sea. “It contains so much junk that it actually doesn’t have much value unless you know how to process it.”
Sulfur
That is also why Venezuelan oil is attractive to American refineries. Unlike many other refineries, they are built on the heavy oil that South America has in abundance. The United States has long been a net importer of oil. Lacking its own oil reserves of that size, the US imported heavy oil from Venezuela from the 1970s onwards for processing in its own refineries. “Nowadays, these installations run on oil from American soil, which they extract from shale. It is lighter, sweeter and easier to process.”
If the oil companies blend the heavier Venezuelan oil into their refineries, then they do now. The question is whether it will come to that. Global oil prices are currently likely too low to invest in the infrastructure needed to extract and transport Venezuelan oil on a large scale.
If it does happen, it will not be good news for the climate. Large amounts of hydrogen are needed to extract the sulfur from the acidic oil. This hydrogen is still produced almost everywhere from natural gas, resulting in greenhouse gas emissions.
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