Lithology and terms of formation of oil-gas Permian-Triassic deposits in the Scythian-Turanian plate throughout the eastern Pre-Caucasus and the South Mangyshlak
Qurbanov Vagif Sh.
The thesis is dedicated to the issues of lithostratigraphy, lithology, oil-gas potential, petrophysical properties of screen rocks, formation analysis, facial-genetic and cyclic structure of formations, paleogeographic terms of their formation and prospects of oil-gas potential.
The author, on the base of rock-geophysical and mineral-petrographic correlations of Permian-Triassic deposits in the eastern Pre-Caucasus and the South Mangyshlak, has developed lithostratigraphic schemes. Having compared them, the author constructed unified general lithostratigraphic scheme of the whole region.
Complex methods of investigations determined material composition of basic rocks forming Permian-Triassic deposits. There has been developed a conception of the formation of dolomitic and chalcedone rocks and mineralogical composition of fragmental rocks has been studied.
On the base of composition of the fragmental rocks there has been studied evolution of the region in the early Mesozoic and its reasons have been determined. On the base on the property of the reflection of vitrinite in the fragmental rocks and argillites and also taking into account thermobaric peculiarities of the medium and post-sedimentation changes of natural reservoirs, there has been created their catagenetic model in the Permian-Triassic deposits.
For the Permian-Triassic deposits in the eastern Pre-Caucasus and the South Mangyshlak, there have been made lithological-stratigraphic maps (scale 1:500 000) of four stages of evolution of the region (late Permian, early Triassic, middle Triassic and late Triassic). For the first time quasiplatform complex of the Scythian-Turanian plate was exposed to the structural-formation analysis from a new point of view. In the Permian-Triassic deposits there have been identified nine formations. By means of these formations there has been verified a tectonic nature of the quasiplatform complex of the Scythian-Turanian plate and the early Mesozoic history of the region`s evolution.
The thesis ends in the assessment of oil-gas potential of the Permian-Triassic deposits in the eastern Pre-Caucasus and the South Mangyshlak depression, on the base of the lithological-paleogeographic criteria.