106 research outputs found
THE INTERNATIONAL CAPITAL MOVEMENT AS A FACTOR OF INFLUENCE ON INNOVATIVE DEVELOPMENT TENDENCY OF UKRAINE’S ECONOMY AND ITS INTEGRATION INTO THE WORLD ECONOMY
The article represents the research results concerning Ukraine’s solving strategic tasks to develop the financial mechanism of regulating the international capital movement and strengthening its positive effect on Ukraine’s economy development tendencies and innovative renewal of its domestic enterprises.The research results regarding Ukraine’s solving the strategic task of financial mechanisms of regulating the international capital movement and strengthening its positive effect on Ukraine’s economic development and innovative renewal of its economy are considered
Absence of the trade-off between the size and number of offspring in the natterjack toad (Bufo calamita)
A trade-off between size and number of offspring was not found for females of similar sizes of the natterjack toad (Bufo calamita). Moreover, for large females, clutches with higher number of eggs had larger eggs as well. This suggests that larger females produce more numerous and larger eggs because they potentially have more energy available for reproduction. Egg size diminished allometrically with clutch size. Egg size, however, did not increase offspring fitness. Therefore, this allometric decrease may be considered a consequence of phylogenetic constraints rather than a result of optimizing selection. © 1992 Springer-Verlag.Peer Reviewe
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Nano- to millimeter scale morphology of connected and isolated porosity in the permo-triassic khuff formation of Oman
Carbonate reservoirs form important exploration targets for the oil and gas industry in many parts of the world. This study aims to differentiate and quantify pore types and their relation to petrophysical properties in the Permo-Triassic Khuff Formation, a major carbonate reservoir in Oman. For that purpose, we have employed a number of laboratory techniques to test their applicability for the characterization of respective rock types. Consequently, a workflow has been established utilizing a combined analysis of petrographic and petrophysical methods which provide the best results for pore-system characterization. Micro-computed tomography (μCT) analysis allows a representative 3D assessment of total porosity, pore connectivity, and effective porosity of the ooid-shoal facies but it cannot resolve the full pore-size spectrum of the highly microporous mud-/wackestone facies. In order to resolve the smallest pores, combined mercury injection capillary pressure (MICP), nuclear magnetic resonance (NMR), and BIB (broad ion beam)-SEM analyses allow covering a large pore size range from millimeter to nanometer scale. Combining these techniques, three different rock types with clearly discernible pore networks can be defined. Moldic porosity in combination with intercrystalline porosity results in the highest effective porosities and permeabilities in shoal facies. In back-shoal facies, dolomitization leads to low total porosity but well-connected and heterogeneously distributed vuggy and intercrystalline pores which improves permeability. Micro- and nanopores are present in all analyzed samples but their contribution to effective porosity depends on the textural context. Our results confirm that each individual rock type requires the application of appropriate laboratory techniques. Additionally, we observe a strong correlation between the inverse formation resistivity factor and permeability suggesting that pore connectivity is the dominating factor for permeability but not pore size. In the future, this relationship should be further investigated as it could potentially be used to predict permeability from wireline resistivity measured in the flushed zone close to the borehole wall. © 2019 by the authors. Licensee MDPI, Basel, Switzerland
Nano- to Millimeter Scale Morphology of Connected and Isolated Porosity in the Permo-Triassic Khuff Formation of Oman
Carbonate reservoirs form important exploration targets for the oil and gas industry in
many parts of the world. This study aims to differentiate and quantify pore types and their relation to
petrophysical properties in the Permo-Triassic Khuff Formation, a major carbonate reservoir in Oman.
For that purpose, we have employed a number of laboratory techniques to test their applicability for
the characterization of respective rock types. Consequently, a workflow has been established utilizing
a combined analysis of petrographic and petrophysical methods which provide the best results for
pore-system characterization. Micro-computed tomography (μCT) analysis allows a representative
3D assessment of total porosity, pore connectivity, and effective porosity of the ooid-shoal facies but it
cannot resolve the full pore-size spectrum of the highly microporous mud-/wackestone facies. In order
to resolve the smallest pores, combined mercury injection capillary pressure (MICP), nuclear magnetic
resonance (NMR), and BIB (broad ion beam)-SEM analyses allow covering a large pore size range
from millimeter to nanometer scale. Combining these techniques, three different rock types with
clearly discernible pore networks can be defined. Moldic porosity in combination with intercrystalline
porosity results in the highest effective porosities and permeabilities in shoal facies. In back-shoal
facies, dolomitization leads to low total porosity but well-connected and heterogeneously distributed
vuggy and intercrystalline pores which improves permeability. Micro- and nanopores are present
in all analyzed samples but their contribution to effective porosity depends on the textural context.
Our results confirm that each individual rock type requires the application of appropriate laboratory
techniques. Additionally, we observe a strong correlation between the inverse formation resistivity
factor and permeability suggesting that pore connectivity is the dominating factor for permeability
but not pore size. In the future, this relationship should be further investigated as it could potentially
be used to predict permeability from wireline resistivity measured in the flushed zone close to the
borehole wall
Применение дисперсионного анализа для исследования свойств промышленных наночастиц никеля
В работе были разработаны методики дисперсионного анализа нанопорошков в водных суспензиях разной концентрации для определения влияния абиотических факторов на агрегативную устойчивость наночастиц.The methods of dispersion analysis of nanopowders in aqueous suspensions of different concentrations were developed to determine the effect of abiotic factors on the aggregate stability of nanoparticles
Petrophysical characterization, BIB-SEM imaging, and permeability models of tight carbonates from the Upper Jurassic (Malm ß), SE Germany
Tight carbonate rocks are important hydrocarbon and potential geothermal reservoirs, for example, in CO2-Enhanced Geothermal Systems. We report a study of outcrop samples of tectonically undeformed tight carbonates from the upper Jurassic “Malm ß” formation in Southern Germany near the town of Simmelsdorf (38 km NE of Nuremberg) to understand bulk petrophysical properties in relation to microstructure and to compare models for permeability prediction in these samples. We applied Archimedes isopropanol immersion, Helium pycnometry, mercury injection, gamma density core logging, and gas permeability measurements, combined with microstructural investigations and liquid metal injection (LMI-BIB-SEM). In addition, ultrasonic velocity was measured to allow geomechanical comparison of stratigraphically equivalent rocks in the South German Molasse Basin (SGMB). Results show only small variations, showing that the formation is rather homogeneous with bulk porosities below 5% and argon permeabilities around 1.4E−17 m2. The presence of stylolites in some of the samples has neither a significant effect on porosity nor permeability. Pores are of submicron size with pore throats around 10 nm and connected as shown by Mercury injection and Liquid Metal injection. Samples have high dynamic Young’s Modulus of 73 ± 5 GPa as expected for lithified and diagenetically overmature limestones. Moreover, no trends in properties were observable toward the faults at meter scale, suggesting that faulting was post-diagenetic and that the matrix permeabilities were too low for intensive post-diagenetic fluid–rock interaction. Petrophysical properties are very close to those measured in the SGMB, illustrating the widespread homogeneity of these rocks and justifying the quarry as a reasonable reservoir analog. Permeability prediction models, such as the percolation theory-based Katz-Thompson Model, Poiseuille-based models, like the Winland, the Dastidar, the capillary tube, and the Kozeny-Carman Models, as well as several empirical models, namely, the Bohnsack, the Saki, and the GPPT Models, were applied. It is shown that the capillary tube Model and the Saki Model are best suited for permeability predictions from BIB-SEM and mercury injection capillary pressure results, respectively, providing a method to estimate permeability in the subsurface from drill cuttings. Matrix permeability is primarily controlled by the pore (throat) diameters rather than by the effective porosity
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