“Anomalous” oils of Tatarstan: Genetic correlations and possible origin

The problem of the origin of oil is still relevant in Tatarstan, in spite of a history of exploration of more than 70 years in combination with complex geological, geophysical, and geochemical studies. In the opinion of some geologists [13], oil deposits of the sedimentary cover in Tatarstan (especially the Romashkinskoe deposit) have a seep with hydrocarbons coming along the hidden fractures and faults from a depth. In addition to ultradeep drilling in the crystalline base ment, the long term geological investigations of physi cochemical properties of oils and the character of works on production wells of the Romashkinskoe deposit were performed in order to study the inflow of abiogenic hydrocarbons in Tatarstan. This resulted in discovery of twelve wells contradicting the law of decreasing pro duction [2]. Some geologists suggest [3] that oil feed ing channels occur beneath these wells, which are called anomalous; such channels provide transportation of abiogenic hydrocarbons to the sedimentary series.