Isotope (δ13C and δ18O) compositions of dolomites from the Permian evaporitic sequences of the Eastern Russian Plate: Evidence from the Syukeevo gypsum deposit

Carbon and oxygen isotope compositions has been studied in dolomites of the Syukeevo gypsum deposit located in the Eastern Russian Plate. Values of δ13C in the dolomites vary from 0.3 to 6.6 ‰; δ18O, from 28.0 to 36.6‰. It is shown that the dolomites were formed in the epicontinental evaporitic basin in different paleoecological settings. This led to the formation of diverse lithological types of dolomites with peculiar isotope-geochemical features. © 2014 Pleiades Publishing, Inc

Traditional and precision methods for studying porous space of oil-bearing formation

At present, the coefficient of porosity is traditionally determined by the method of Preobrazhensky and by the results of a petrophysical interpretation of well log data. However, there are many examples of the significant error in its determination, which ultimately affects the determination of their filter-capacitance properties, the recovery rate of oil and extracted reserves. In this paper, the porosity coefficients are compared by traditional and precision methods for oil-containing terrigenous reservoirs of the Paschian (Upper Devonian), and Tula and Bobrikovskian (Lower Carboniferous) horizons, as well as carbonate reservoirs of the Tournaisian stage, using the example of one of the deposits in the central part of the Volga-Ural oil and gas province. It is shown that precision methods make it possible to study in more detail the internal pore space of oil-containing reservoirs. X-ray computer microtomography showed the uneven and multidimensional porosity of Devonian sandstones, due to their micro-lamination. The most accurate values of the porosity coefficient from the results of microtomography were obtained for cubes of the smallest size (with linear dimensions of the sample less than 5 mm), so they correspond to a higher resolution of the survey, which allows detecting smaller pores. In this connection, the inverse dependence of the porosity coefficient on the size of the samples was established. Variability of porosity along the layers in the lateral direction is revealed (the property of 'microfaciality'). The combination of traditional and precision methods for determining porosity coefficients will allow us to calculate the oil recovery factor on explored and developed oil deposits more correctly, because additional information on pore size and cavity, connectivity and type of channels, as well as microfacies are taken into account

The possibility of using space correlation with microspheres petroleum deposits

The article presents data on the microspheres in Phanerozoic sediments of the Caspian Basin. It found almost perfect spherical formations diameter 170-950 microns. Studies were performed using microspheres of scanning electron microscopy with a microprobe analysis by X-ray. In mineralogical respect to the scope composed mainly of magnetite. Trace elements (Si, Al, Mn) in the microspheres increased from Paleozoic to Cenozoic deposits that can be used in the future as a geochemical criterion for stratigraphic correlation sections. In Cenozoic microspheres missing potassium and chromium, as noted in Paleozoic microspheres high chlorine content, which may be due to the presence of hibbingita. Textured surface of the microspheres (takyrs, plates, ribs, triangular depression, etc.), the presence of nickel and titanium impurities absence indicate their cosmic origin. Microspheres can be used as benchmarks in the search mikrostratigraficheskih hydrocarbons in sediments of different facies

Cosmic microspheres in the Carboniferous deposits of the Usolka section (Urals foredeep)

© 2017Magnetite microspheres from the Carboniferous deposits of the Usolka reference section were studied by probe microanalysis, with comparison of the distributions of chemical elements and microspheres. The presence of microspheres in sedimentary strata is considered to be an additional factor for stratigraphic correlation between sedimentary sections. The microspheres are shown to be of cosmic nature. The Late Paleozoic paleoclimatic changes (extreme cooling) and biotic crises were caused by the periodical Solar System motion in the Galaxy, cosmic-dust fallout, and meteorite bombardments of the Earth

Isotope (δ13C and δ18O) compositions of dolomites from the Permian evaporitic sequences of the Eastern Russian Plate: Evidence from the Syukeevo gypsum deposit

Carbon and oxygen isotope compositions has been studied in dolomites of the Syukeevo gypsum deposit located in the Eastern Russian Plate. Values of δ13C in the dolomites vary from 0.3 to 6.6 ‰; δ18O, from 28.0 to 36.6‰. It is shown that the dolomites were formed in the epicontinental evaporitic basin in different paleoecological settings. This led to the formation of diverse lithological types of dolomites with peculiar isotope-geochemical features. © 2014 Pleiades Publishing, Inc

Isotope (δ13C and δ18O) compositions of dolomites from the Permian evaporitic sequences of the Eastern Russian Plate: Evidence from the Syukeevo gypsum deposit

Carbon and oxygen isotope compositions has been studied in dolomites of the Syukeevo gypsum deposit located in the Eastern Russian Plate. Values of δ13C in the dolomites vary from 0.3 to 6.6 ‰; δ18O, from 28.0 to 36.6‰. It is shown that the dolomites were formed in the epicontinental evaporitic basin in different paleoecological settings. This led to the formation of diverse lithological types of dolomites with peculiar isotope-geochemical features. © 2014 Pleiades Publishing, Inc

Isotope (δ13C and δ18O) compositions of dolomites from the Permian evaporitic sequences of the Eastern Russian Plate: Evidence from the Syukeevo gypsum deposit

Carbon and oxygen isotope compositions has been studied in dolomites of the Syukeevo gypsum deposit located in the Eastern Russian Plate. Values of δ13C in the dolomites vary from 0.3 to 6.6 ‰; δ18O, from 28.0 to 36.6‰. It is shown that the dolomites were formed in the epicontinental evaporitic basin in different paleoecological settings. This led to the formation of diverse lithological types of dolomites with peculiar isotope-geochemical features. © 2014 Pleiades Publishing, Inc

Traditional and precision methods for studying porous space of oil-bearing formation

At present, the coefficient of porosity is traditionally determined by the method of Preobrazhensky and by the results of a petrophysical interpretation of well log data. However, there are many examples of the significant error in its determination, which ultimately affects the determination of their filter-capacitance properties, the recovery rate of oil and extracted reserves. In this paper, the porosity coefficients are compared by traditional and precision methods for oil-containing terrigenous reservoirs of the Paschian (Upper Devonian), and Tula and Bobrikovskian (Lower Carboniferous) horizons, as well as carbonate reservoirs of the Tournaisian stage, using the example of one of the deposits in the central part of the Volga-Ural oil and gas province. It is shown that precision methods make it possible to study in more detail the internal pore space of oil-containing reservoirs. X-ray computer microtomography showed the uneven and multidimensional porosity of Devonian sandstones, due to their micro-lamination. The most accurate values of the porosity coefficient from the results of microtomography were obtained for cubes of the smallest size (with linear dimensions of the sample less than 5 mm), so they correspond to a higher resolution of the survey, which allows detecting smaller pores. In this connection, the inverse dependence of the porosity coefficient on the size of the samples was established. Variability of porosity along the layers in the lateral direction is revealed (the property of 'microfaciality'). The combination of traditional and precision methods for determining porosity coefficients will allow us to calculate the oil recovery factor on explored and developed oil deposits more correctly, because additional information on pore size and cavity, connectivity and type of channels, as well as microfacies are taken into account

Traditional and precision methods for studying porous space of oil-bearing formation

At present, the coefficient of porosity is traditionally determined by the method of Preobrazhensky and by the results of a petrophysical interpretation of well log data. However, there are many examples of the significant error in its determination, which ultimately affects the determination of their filter-capacitance properties, the recovery rate of oil and extracted reserves. In this paper, the porosity coefficients are compared by traditional and precision methods for oil-containing terrigenous reservoirs of the Paschian (Upper Devonian), and Tula and Bobrikovskian (Lower Carboniferous) horizons, as well as carbonate reservoirs of the Tournaisian stage, using the example of one of the deposits in the central part of the Volga-Ural oil and gas province. It is shown that precision methods make it possible to study in more detail the internal pore space of oil-containing reservoirs. X-ray computer microtomography showed the uneven and multidimensional porosity of Devonian sandstones, due to their micro-lamination. The most accurate values of the porosity coefficient from the results of microtomography were obtained for cubes of the smallest size (with linear dimensions of the sample less than 5 mm), so they correspond to a higher resolution of the survey, which allows detecting smaller pores. In this connection, the inverse dependence of the porosity coefficient on the size of the samples was established. Variability of porosity along the layers in the lateral direction is revealed (the property of 'microfaciality'). The combination of traditional and precision methods for determining porosity coefficients will allow us to calculate the oil recovery factor on explored and developed oil deposits more correctly, because additional information on pore size and cavity, connectivity and type of channels, as well as microfacies are taken into account