Место издания: Florence , Год издания: 2004

Two sets of formation waters differing in the content and composition of bitumoids (aqueous bitumoids - AB) have been recognized in the West Siberian petroleum basin. Aqueous bitumoids from set I of formation waters provide genetic characteristics of the basin's regional background resulted from the primary migration of petroleum components. AB from set II are associated with geochemical anomalies caused by an areal of petroleum compounds dispersed from the pools. The latest data presented in this paper provide the updated consideration of geochemistry of the set I AB, give a review of the AB content in the basin formation waters, group and HC composition of AB. Special attention was paid to non-degraded biomarkers identified in AB. The use of the cluster analysis allowed aqueous bitumoids to be divided into three families with specific biomarker identity as well as spatial and stratigraphic localities. As shown, the entire compound complex peculiar to the bitumoids of dispersed organic matter and oils is to be migrated with water, so that AB could be considered direct evidences of the primary migration. Based on the hydrocarbon composition of aqueous bitumoids we can establish the distinct genetic relationship HC of dispersed OM - HC of AB - HC of oil, thus identify the precusor of crude oils. The Bazhenov Formation is known to have been the principal present-day source of AB migrating within the West Siberian basin. It was shown that the formation waters of West Siberia contain large amount of migrating crude oil and hydrocarbon gases. With numerous elision water cycles in the basin, even with significant dispersion, they could provide the present day oil and gas resources. Presented information enable us to settle controversial points of a sedimentary-migration theory of the oil origin.