Mysteries of petroleum stay locked

Although petroleum is one of the most studied substances on Earth, it remains essentially mysterious, elusive.

In some respects, crude resembles blood. It scabs on exposure to air. It is organic and viscous. It sometimes is warmed to about 90 degrees to make it flow through pipelines more easily.

Oil is not sterile. It supports bacteria and fungi. "Vines" of oil-eating algae — some many feet long — have been found inside old storage tanks.

Every day in the United States, scores of gasolines or crudes gurgle simultaneously through pipelines. Engineers have designed pipes to "roll" contents forward rather than squirt them in laminar flows. In this way, a carefully calibrated degree of turbulence keeps the fuels from blending. What little does get mixed is called "slop" and must be refined again.

Perhaps the most remarkable thing about oil is this: After 150 years of unleashing its explosive power to shrink the world and expand our dominion of nature, and after reshaping it into innumerable useful byproducts — from plastic cradles to vinyl body bags — we still do not understand fully where oil comes from or how it was made.

The notion that it is the cooked and condensed remains of dinosaurs is at best marginally correct. Most geologists agree that terrestrial life never existed in sufficient abundance to explain the vast amount of crude now lurking in the ground.

Instead, many scientists think petroleum was born in water — as algae and minute life forms called plankton. The plants bloomed, died and were buried in sea-bottom silts.

But this remains a theory. No one has yet synthesized crude from dead plant matter.