Science: The Oil Bugs

Great oilfields may come from little bacteria. So says Dr. Claude E. ZoBell, a California "geomicrobiologist." He has proved that bacteria and petroleum cross each other's paths all along the line.

Dr. ZoBell examined fluids which rose to the surface of oil wells and found them teeming with bacteria. The same hardy bugs had been found by other observers, who wondered why they were there. Dr. ZoBell had a strong suspicion that they were old settlers: descendants of ancestors who had homesteaded in the oil sands millions of years ago. To prove it, he investigated the oozy, smelly mud and slime at the bottom of the sea, which most authorities think are oil sands in embryo.

Dr. ZoBell's theory: the bodies of sea creatures, large & small, turn into petroleum if covered deeply and given plenty of time. Dr. ZoBell collected bacteria from samples of deep-buried sea mud. When carefully tended and properly fed, the bugs produced a fair facsimile of petroleum, right in the laboratory. Some turned the fatty acids of decomposed animals into hydrocarbons characteristic of petroleum.

Dr. ZoBell also found that certain bacteria etch little holes in limestone, allowing petroleum to percolate through. Others give off gases, forcing oil out of dead-end pores. Others pry oil films off mineral surfaces. All these quiet, persistent activities probably help the oil to collect in large underground pools.

Some bacteria thrive on the blackest, gummiest oil. When a wild well sprays the neighborhood, it poisons the soil for vegetation. But in a year or so, the oil is gone. Bacteria have eaten it up and fertilized the soil with their corpses, leaving it richer than before.

These hungry oil-eaters promise a new method of spotting oilfields. Hydrocarbon gases, such as ethane and propane, often leak in small quantities through the cap rock above an oil pool. When they reach the surface soil, bacteria lap them up, thrive and multiply. By looking for such bacteria, or signs of their past activity, geologists may smell out their larder, the oil pool down below.