Abstract

"The idea of a `metamorphic' evolution of petroleum arose from the consideration of differences existing in chemical structure of crude oils within each sedimentary basin, and from certain regularities, which seem to indicate a relationship between the structure of oils and such geological parameters as age and depth of their reservoirs. This concept of evolution of petroleum was strictly connected with the classical hypothesis of the origin of oil in `source rocks,' through complex transformations of biologic matter. Recent studies on migration of hydrocarbons and on the composition of crude oils have led to a substantially new picture of origin and alteration of oil deposits. The new ideas are reviewed, with particular reference to their implications in the problem of evolution of petroleum."