scholarly journals Evidence of carbonate rocks formation on geochemical barriers in black shale on the example of the Bazhenov formation of the Western Siberia

Georesursy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 143-152
Author(s):  
Vika G. Eder ◽  
Alvina G. Zamiraylova ◽  
Georgii A. Kalmykov
Keyword(s):  
Carbonate Rocks ◽  
Western Siberia ◽  
Upper Jurassic ◽  
Carbonate Content ◽  
Low Carbon ◽  
Bazhenov Formation ◽  
Geochemical Barriers ◽  
Upper Limit ◽  
Geochemical Parameters ◽  
Geochemical Study

A comprehensive lithological-geochemical study of rocks of the Upper Jurassic-Lower Cretaceous blackshale Bazhenov formation showed that most of its carbonatized interlayers to the boundaries of packs of different composition differing in carbonate content, degree of siliceousness or clayiness. At the same time, at the boundaries of the Bazhenov formation with host sediments, where carbonate rocks are often found in association with “pyrite” low carbon rocks according to geochemical parameters (degree of pyritization, Mn/Al, Ua), a change in the redox regime is recorded. In the most studied stratum at intervals of occurrence of carbonates, a change in the redox regime is not observed. It is assumed that they existed alkaline barriers, as evidenced by the change in the composition of rocks. The following geochemical barriers (bottom-up along the section) were identified in the Bazhenov formation and its transition to the enclosing sediments, on which evidence of localization of carbonate minerals was found: redox barrier 1 (lower BF boundary), alkaline barrier 1 (border of mixes of kerogen - clay-siliceous low-carbonate and silicites), alkaline barrier 2 (border of kerogen-clay-siliceous low-carbonate and siliceous-carbonate “coccolith” packs); Redox barrier 2 (the upper limit of the BF).

scholarly journals New data on lithology, organic geochemistry and accumulation conditions of the Bazhenov formation in Western Siberia

Georesursy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 129-142 ◽  
Author(s):  
Vika G. Eder ◽  
Elena A. Kostyreva ◽  
Anna Yu. Yurchenko ◽  
Natalia S. Balushkina ◽  
Inga S. Sotnich ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carbonate Rocks ◽  
Western Siberia ◽  
Organic Geochemistry ◽  
Carbonate Content ◽  
Reservoir Properties ◽  
Bottom Part ◽  
Bazhenov Formation ◽  
Lithological Composition ◽  
Transformation Of Organic Matter

This paper presents data on lithological composition, distribution, reservoir properties, geochemistry of organic matter and genesis of carbonate rocks of the Bazhenov formation within the central part of Western Siberia (the region of the Khantei hemianteclise). The following types of carbonates are distinguished: a) primary biogenic – shell rock interlayers and residues of coccolith; b) dia- and catagenetic – in varying degrees, recrystallized rocks with coccoliths, nodules and aporadiolarites; c) catagenetic – cracks healed with calcite in limestone of the foot of the Bazhenov formation. It was determined that the crystallization of the carbonate material of nodules took place in various conditions: in the bottom part of the sediments and in the later stages of diagenesis. The source of calcite for nodules was calcareous nanoplankton or bivalve shells. The carbonate content of the cuts decreases in the following sequence: Yuzhno-Yagunsky → Povkhovsky → Novortyagunsky → Druzhny areas, which are associated both with facial features and various physicochemical conditions of diagenesis and catagenesis. Transformation of organic matter increases in the northeast direction from South Yagunsky to Povkhovsky area, which is confirmed by molecular parameters of catagenesis. The carbonate rocks of the bottom part of the Bazhenov formation in the South Yagunsky area are similar in structure to the main oil-bearing reservoirs of the Salym and Krasnoleninsky fields.

scholarly journals Alginite-Rich Layers in the Bazhenov Deposits of Western Siberia

Geosciences ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 252
Author(s):  
Timur Bulatov ◽  
Elena Kozlova ◽  
Evgeniya Leushina ◽  
Ivan Panchenko ◽  
Natalia Pronina ◽  
...  
Keyword(s):  
Western Siberia ◽  
Isotope Composition ◽  
Upper Jurassic ◽  
Type I ◽  
Distinctive Features ◽  
Bazhenov Formation ◽  
Predominant Component ◽  
Petroleum Generation ◽  
Rock Eval ◽  
Kinetics Of

In this study, we identified the luminescent layers containing a significant amount of alginite in the Upper Jurassic–Lower Cretaceous Bazhenov Formation named “the alginite-rich layers”. Lithological and geochemical methods were used to determine distinctive features of these layers and to evaluate their impact on the total petroleum generation potential of the Bazhenov Formation. We have shown that the composition of the alginite-rich layers differs significantly from the organic-rich siliceous Bazhenov rocks. Rock-Eval pyrolysis, bulk kinetics of thermal decomposition, elemental analysis, and the composition of pyrolysis products indicate type I kerogen to be the predominant component of the organic matter (OM). Isotope composition of carbon, nitrogen, and sulfur was used to provide insights into their origin and formation pathways. The luminescent alginite-rich layers proved to be good regional stratigraphic markers of the Bazhenov Formation due to widespread distribution over the central part of Western Siberia. They can also be applied for maturity evaluation of the deposits from immature to middle of the oil window, since the luminescence of the layers changes the color and intensity during maturation.

scholarly journals SIGNATURES OF PYRITIZATION OF TRANZITION ZONES FORM THE BAZHENOV FORMATION TO ENCLOSED DEPOSITS IN THE UPPER JURASSIC-LOWER CRETACEOUS WESTERN SIBERIAN BASIN

2019 ◽  
Vol 2 (1) ◽  
pp. 200-205
Author(s):  
Vika Eder ◽  
Alvina Zamirailova
Keyword(s):  
Lower Cretaceous ◽  
Upper Jurassic ◽  
Bacterial Activity ◽  
Bazhenov Formation ◽  
Geochemical Barriers ◽  
Redox Indicators

In the transitional zones from the Bazhenov Formation and to the enclosing deposits the complex of litological-geochemical researches, including the analysis of sections structure, distributions of C/S ratio and redox indicators (degree pyritization, authigenous uranium, Mn/Al) were made. It is defined that rocks on the borders with the Bazhenov Formation at the enclosing deposits are low carbonaceous with rather high content of pyrite; in the Bazhenov Formation near its roof in many cases rocks are characterized by approximately equal high contents of pyrite and kerogen. It is established that the pyritization of rocks on these intervals resulted by thermochemical sedimentation of iron from solutions on redox geochemical barriers without participation of bacterial activity.

scholarly journals Composition and age of monacite fragments from superior jurassic terrigenous sediments of bazhenov formation foundation (multan area in west siberia)

2020 ◽  
Vol 33 (01) ◽  
pp. 84-93
Author(s):  
Yuriy V. Erokhin ◽  
Kirill S. Ivanov ◽  
Vera V. Khiller
Keyword(s):  
Rare Earth ◽  
Western Siberia ◽  
Chemical Properties ◽  
West Siberia ◽  
Upper Jurassic ◽  
Yenisei Ridge ◽  
Bazhenov Formation ◽  
Terrigenous Sediments ◽  
Lower Proterozoic ◽  
Rare Earth Phosphate

Bazhenov Formation is regarded as the main oil-bearing stratum mothering nearly all the fields of the Western Siberia Oil-Gas-bearing Megabasin. Presently, it is one of the most studied formations of Siberia and, probably, Eurasia as a whole. While there is an enormous amount of studies devoted to the Bazhenov Formation, there are no detailed mineralogical studies at the modern hardware level. The age and sources of the terrigenous materials of the formation have not been studied as well. We have explored the detrital monazite from the upper-Jurassic terrigenous sediments of the Multan Area at the foundation of the Bazhenov Formation in the central part of Western Siberia, Surgut District. All the detrital rare earth phosphate is of the cerium kind being a monazite-(Се). The mineral is rather dissimilar in respect of its chemical properties, especially, the content of thorium. Some fragments have been subjected to superposed secondary changes. The detrital monazite is rounded to various degrees which is indicative of the various distances from the rare earth phosphate orebody washout. As per the chemical data, most of the monazite has been washed out from the medium and basic rocks (probably subalkaline or alkaline) as well as the sialic rocks (granitoids and associated veins). According to the chemical dating, most of the monazite fragments have been washed out of the very ancient Proterozoic formations and lower-Proterozoic rocks. Terrigenous materials derives probably from the rock assemblages of the eastern and south-eastern fringes of the Western Siberian megabasin such as the Proterozoic Yenisei Ridge or Lower-Proterozoic blocks of the Altay and Sayan Faulting.

scholarly journals Types of Void Space in the Bazhenov Reservoir Rocks

Geosciences ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 269
Author(s):  
Olga V. Postnikova ◽  
Alexander V. Postnikov ◽  
Olga A. Zueva ◽  
Artem E. Kozionov ◽  
Ekaterina V. Milovanova ◽  
...  
Keyword(s):  
Western Siberia ◽  
Distribution Patterns ◽  
Void Space ◽  
X Ray Diffraction ◽  
Bazhenov Formation ◽  
Reservoir Rocks ◽  
Oil Reserves ◽  
Light Oil ◽  
Clay Rocks ◽  
High Degree

The deposits of the Bazhenov formation are a unique reservoir of unconventional oil reserves in Western Siberia. They contain both solid organic matter (kerogen) and liquid light oil. The successful development of these hydrocarbons is largely determined by the adequacy of the void space models. The aim of the study is to identify the types of void space in the sediments of the Bazhenov formation and to identify the distribution patterns across the section of the researched wells. The void space was studied by electron and optical microscopy, and the mineral composition of the rocks was determined by X-ray diffraction analysis. The deposits of the Bazhenov productive formation in the territory of Western Siberia are represented by a wide complex of lithotypes, including various kinds of silicites, carbonate, clay rocks, and mixtites. The reservoir space in the reservoir rocks of the Bazhenov formation is a complex and hierarchically subordinated system, which includes voids and fractures of various sizes, configurations, and genesis. The void space of the Bazhenov formation is characterized by a fairly high degree of spatial heterogeneity, which is controlled by lithological, facies, and tectonic factors, as well as the direction of catagenetic processes.

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