It seems many geologists are being petty, arguing over facts that have yet to yield answers about crude oil. The mid July 04 Hedberg Conference by American Association of Petroleum Geologists again discussed biogenic versus abiotic origins of hydrocarbons, an interesting and very significant industrial issue. At current rates of world consumption (over 26 billion barrels a year) and with 80% coming from fields discovered before 1973, end of supply is always a concern because proven reserves are only 1,213 billion barrels, 75% of which is in 370 fields worldwide. It is projected that production rates will peak in 2037 unless new reserves are found and sharply decline thereafter.
Then along comes Dr. Thomas Gold, professor emeritus at Cornell and an astronomer no less, who says not to worry. Petroleum is a renewable resource made deep in the earth by inorganic processes (abiotic - an idea first proposed by Russian scientist Mikhail Lomonosov in 1757 who called it "rock oil") and does not come from piles of dead dinosaurs and fermenting leaves (biogenic). The conventional wisdom of petroleum geologists has been offended and most of them are steamed.
Crude oil is a primordial soup but not of biologic origin, says Dr. Gold, forming under great heat and pressure in the deep biosphere and hydrocarbons we now know are common on planetary bodies. The abiotic theory is that methane, the simplest carbon molecule (CH4) we call natural gas, is formed from carbonate rocks and water at depths of 5 to 20 miles, at pressures of 30 to 45 kilobars (441 to 662 ksi), and temperatures approaching 800°C (1470°F). Then the methane condenses into heavier hydrocarbons we call petroleum, collecting in subterranean pools. Most geologists agree so far; you can make oil artificially with these conditions. However the abiotic theory as a natural event is different, supported by these facts:
- High oil quantities are found in locations where assays of prehistoric life are not sufficient to have produced the existing reserve.
- Oil produced from varying depths from the same field has the same chemistry and does not vary as the fossil life changes with depth at these same spots.
- Every oil field outgases helium, which does not appear in meaningful quantity in any other venue, and is a thoroughly stable, inorganic gas that is a product of radiologic decay of rocks appearing at great depths within the Earth mantle.
The abiotic theory is rejected by geologists who cite these facts:
- Petroleum deposits occur mainly in horizontal, near-surface reservoirs.
Commercial oil fields produce a low content of C-13 isotope in molecules because plant life has available and absorbs the common C-12 isotope; deposits of deep methane have a higher content of the less common (1% of all carbon) C-13 atom.
Actually, it may well be that both protagonists for their cause (antagonists if you prefer) have strength in their arguments. It is known that hydrocarbons migrate within the Earth's crust as witnessed by production at Eugene Island in the Gulf of Mexico 80 miles south of Louisiana. In 1973 when discovered, it produced 15,000 bpd but dwindled to 4,000 bpd by 1989. Inexplicably it resumed output to 13,000 bpd but has confounded geologists because current production is of a significantly different (newer) geologic age than yesteryear. Abiogenic proponents say it is being refilled from beneath the formation and that as oil migrates upward; it is attacked by bacteria that alter its appearance. It is known that such bacteria (hyperthermophiles) live at great depths, recorded in Alaska at 4.2 km and in Sweden at 5.2 km (2.6 and 3.2 miles) below the surface.
There has been a long history of this argument. Mendeleyev, who discovered the Periodic table, said in 1870 the same thing offered in 1962 by Sir Robert Robinson of Britain's Royal Society that "petroleum is a primordial hydrocarbon to which biological products have been added." That's quite similar to what Dr. Gold is touting and is of enormous importance due to geopolitics and economic impacts of the highly inelastic supply and demand system existing in the world. If abiotic petroleum formation is true, how much reserve really exists on Earth, and more importantly, is human consumption depleting supply faster than replenishment?
For further reading, see http://www. worldnetdaily.com/news/article.asp?ARTICLE_ID=38645
It will be interesting to hear what the Hedberg Conference determined, if any conclusions emerge. It might also be appropriate to remember the adage-actually the warning-my father taught me: "It's the things we know for certain that just ain't so."