The concept of the organic origin of petroleum has been dominant for the last 70 years. Generation of petroleum hydrocarbons has been explained by transformation of dissipated organic matter in clay-carbonate sediments under the influence of temperature and pressure increase with depth, separation of the hydrocarbons freshly generated, and their migration into porous reservoir beds. According to the organic-origin concept, the extremely low content of hydrocarbons in the rocks is unimportant, because the existence of a huge mass of "source" rocks for the petroleum generated solves the problems of petroleum-migration mechanism, petroleum accumulation, petroleum formation, and its spatial distribution.

In the course of time this concept of the organic petroleum source rocks has become a dogma, and all questions of petroleum geology and exploration are approached from the assumption that the organic origin is proved. Many works are devoted to a thorough and detailed study of the various consequences of the origin concept.

However, while the organic theory proliferated, the concept of the inorganic synthesis of hydrocarbons and plutonic origin of petroleum also grew. These concepts, associated mainly with the names of prominent scientists of the 19th century, were considered by the organic-theory protagonists to be obsolete. As a result they were shelved, as explained in detail by Hedberg and by Dott and Reynolds.

However the stream of new information coming from new exploration areas and from new ideas in the fields of geology, geochemistry, geophysics, astrophysics, and so on has contributed to appearance of new knowledge which categorically rejects all aspects and consequences of the organic theory. The struggle between the opposing theories finally focused into broad discussions--including symposia accompanied and followed by many publications on the problem, especially in the socialist countries. Unfortunately all this is unknown to foreign petroleum geologists, as can be judged by study of the works of Hedberg, Colombo, Levorsen, Dott and Reynolds, and others.

The aim of the present survey is to bring to the attention of a wide circle of geologists the new ideas and a picture of the present state of the problem of petroleum formation from the viewpoint of inorganic-origin theory.