The Origin and Chemistry of Oil
Most scientists agree that hydrocarbons (oil and natural gas) are of organic origin. A few, however, maintain that some natural gas could have formed deep within the earth, where heat melting the rocks may have generated it inorganically.1 Nevertheless, the weight of evidence favors an organic origin, most petroleum coming from plants and perhaps also animals, which were buried and fossilized in sedimentary source rocks.2 The petroleum was then chemically altered into crude oil and gas.
The chemistry of oil provides crucial clues as to its origin. Petroleum is a complex mixture of organic compounds. One such chemical in crude oils is called porphyrin:
Petroleum porphyrins have been identified in a sufficient number of sediments and crude oils to establish a wide distribution of the geochemical fossils.3
They are also found in plants and animal blood4 (see sidebar Porphyrins).
Porphyrins
Porphyrins are organic molecules that are structurally very similar to both chlorophyll in plants and hemoglobin in animal blood.1 They are classified as tetrapyrrole compounds and often contain metals such as nickel and vanadium.2 Porphyrins are readily destroyed by oxidizing conditions (oxygen) and by heat.3 Thus geologists maintain that the porphyrins in crude oils are evidence of the petroleum source rocks having been deposited under reducing conditions:
The origin of petroleum is within an anaerobic and reducing environment. The presence of porphyrins in some petroleums means that anaerobic conditions developed early in the life of such petroleums, for chlorophyll derivatives, such as porphyrins, are easily and rapidly oxidized and decomposed under aerobic conditions.4
References
1.McQueen, D.R., The chemistry of oil容xplained by Flood geology, Impact #155, Institute for Creation Research, Santee, California, 1986.
2.Tissot, B.P., and Welte, D.H., Petroleum Formation and Occurrence, 2nd ed., Springer-Verlag, Berlin, pp. 409?10, 1984.
3.Russell, W.L., Principles of Petroleum Geology, 2nd ed., McGraw-Hill Book Company, New York, p. 25, 1960.
4.Levorsen, p. 502.
