Suchergebnisse

The article presents the first results of determining the content of different types of bound water by hygrometric method — adsorption isotherm method — for non-extracted air-dry samples of Bazhenov formation rocks. The obtained water sorption isotherms for the studied samples have a well-expressed s-shape, which allows to determine the maximum possible amount of bound water of different types in them — mono-, poly — and capillary condensation and to draw an important conclusion about the hydrophilicity of the Bazhenov formation deposits. According to the form of sorption isotherms, the amount of bound water and the proximity of mineral compositions, nine samples were combined into 4 different groups, the remaining samples were considered individually. A correlation between the pore water content and the content of mono- and multilayer water was found.

Recently, there are more and more investigations devoted to plastic pollution of the natural environment. In this case an active attention is paid to microplastic particles (MPs) less than 5 mm size and nanoplastic particles (NPs) less than 100 nm in size. MP and NP particles are found practically everywhere: in waters and bottom sediments of the World Ocean, river, lake and groundwater, beach sediments and even in snow and ice of the Arctic and Antarctic, in foodstuff, bottled water, in living organisms at all stages of the food chain. Plastic pollution of the natural environment has already become as global as climate change. This article presents the results of the analysis and summary of the current published literature devoted to the problems of MP and NP pollution of natural waters, mainly on the territory of the Russian Federation. For the first time, a schematic map of MP distribution in surface waters of Russia is constructed. A summary table on MP concentrations in surface water, groundwater, bottled mineral and tap water, bottom sediments of rivers, seas and oceans of the world is presented. It is clearly shown that there is a shortage of studies of MP and NP contamination in groundwater, although their content is also quite high.In addition, the paper touches upon the problem of measuring the MP and NP content and determining its composition, highlights the features, advantages, disadvantages and limitations of all the main detection methods. The summarized schemes of water and soil sampling and preparation for the following MP determination are presented. A reasonable conclusion is made that at the present moment there is no one optimum method, and only a combination of methods allows to identify MP and NP contamination in the best way.

The paper presents for the first time a reliable dataset on formation water salinity and salt composition for tight shale formations of Bazhenov, Achimov and Georgiev suites. The data were obtained in the result of laboratory analysis of aqueous extracts from rock samples before and after its hydrocarbon extraction (cleaning). Based on the experimental data a thermodynamic modeling of solution-mineral equilibrium was performed followed by Na/Cl, Ca/SO4, Mg/SO4, Ca/Cl, Ca/HCO3, Fe/SO4 correlation analysis. The results shown that concentrations of certain macro-components, including Ca, Mg, Fe, hydrocarbonate and sulfate ion in pore solutions cannot be reliably determined using aqueous extract data. At the same time a reliable estimate nominal salinity of formation water could be provided using the obtained data. The paper concludes that a reliable study of macro-components' chemical composition in formation waters of tight shale formations requires laboratory analysis of non-extracted rock core samples with maximal preservation of water content.

The reservoir water content is one of the key parameters to following reliable hydrocarbon reserves estimation of low-permeable shale reservoirs with unconventional hydrocarbon reserves. The extensive review of applied direct and indirect laboratory methods for determining the water saturation in unconventional shale reservoirs is presented in this article. The essence, advantages, disadvantages and limitations of methods are described in detail. It was demonstrated that direct laboratory methods (retort method, Zaks, Dean–Stark) which were originally developed for traditional reservoir rocks, give results with an error of up to 50% for rocks samples of unconventional reservoirs. On the other hand the Evaporation Method specifically developed for low-permeable rocks takes less time and provides more accurate (error up to 6.8%) gravitational and bonded water determination moreover, it requires up to 5 times less rock material for analysis.

The paper provides experimental characterization of the ion-exchange capacity of low-permeable shale rocks of the Bazhenov Formation of the central and southern parts of the Nizhnevartovsk arch, Western Siberia. We found that the cation exchange capacity (3.30–17.01 meq/100g) and the specific surface area (10.05–12.66 m2/g) depend on the clay minerals content, but not on the kerogen. The paper describes type of the exchange complex of the studied Bazhenov Formation rock samples and discusses the possible reasons for the distribution of exchangeable cations. The cation exchange complex of most part of studied Bazhenov Formation samples has a marine type (rCa/(rNa+rK)<1).

The paper presents the pore waters composition's experimental results in the northeastern part of the Barents Sea. The pore water contains Cl–, Na+, SO4 2– and Mg2+ as dominant components and is quite similar to the Barents Seawater composition. For the first time, we measured the cation exchange capacity of (13.98-35.50 meq/100 g) and the exchanging cations composition (Na+>Mg2+>Ca2+>K+) of bottom sediments. We find that most of the sampled pore water (near 90%) have marine nature, and only near 10% is slightly transformed with sulfate reduction processes due to the diagenesis. We measure that the rare earth elements (REE) content in pore water is up to 1.589 μg/L with their content in sediments up to 144.051 mg/kg, negative cerium and positive europium anomalies are observed both in the pore waters and in bottom sediments. We calculated using PHREEQC that pore water undersaturated to gypsum and halite and supersaturated to calcite and dolomite, which may precipitate in deposits during diagenesis.

The paper presents a research approach to study the ion-salt complex composition of the Bazhenov shales of the Western Siberia. The approach is based on application of the water and ammonium extracts of the rock samples with the natural moisture content, after the heating and storage, the X-ray spectrometry and high-resolution mass spectrometer with inductively-coupled plasma ionization. It was found that the water extracts composition from the natural Bazhenov rocks is a sulfate sodium bicarbonate type with high content of silic acid and slightly alkaline pH values. The solid and liquid contents of barium, boracium, zinc, vanadium, uranium, arsenic are in excess of their percentage abundance more than in 2-10 times. The barium content in pore water is higher than strontium content in 10 times. It was mesured that a sodium dominates in the rock exchange complex, the cation exchange capacity is 14-19 meq/100 g.

The paper presents the experimental results of the rare earth elements and yttrium (REY) biosorption in the natural surface waters and groundwater in the presence of living and inactivated organotrophic bacteria (Curtobacterium sp., Ralstonia sp., Pseudomonas sp., Bacillus sp., Brevibacterium sp., Microbacterium sp.,) under different environmental pH conditions. We find that the biosorption process is mainly regulated by two factors: the aqueous solution's pH and the bacteria strains concertation. The water acidity significantly effects on the bacteria sorption capacity for all studied strains. We discover a decrease in REY sorption with an increase in pH due to lower absorption of REY on the cell walls of bacteria. The process of REY biosorption proceeds more intensively by living bacteria than in the presence of inactivated microorganisms. We observe that at neutral pH values all studied bacterial strains sorb light REY (lanthanum, praseodymium, neodymium), in more acidic solutions (pH 2) the heavy ones (lutetium, europium). The REY sorption decreased with an increase in the living and inactivated bacterial concentration.

The quantitative characteristics of the macro- and micro-component composition of the pore solutions of the see bottom sediments according to the direct analysis and the calculations from the water extracts are presented. The conclusion about the possibility of the water extracts method using to determine the salinity and chemical composition of the nature pore waters of the low permeable clay deposits of the different lithification stages was made. It was found that the water extracts solutions does not allow to accurately determine the composition of the natural pore solution, but its make it possible to estimate the content of chlorine, sodium and bromine within the error of the determination.

This study shows the experimental results of the rare earth element and Y (REY) distribution patterns between heterotrophic bacteria and water under acidic pH conditions for five different bacterial strains (Microbacterium sp., Curtobacterium sp., Bacillus subtilis, Pseudomonas putida, Bacillus pumilis) which are widespread in natural and technogenic ground- and surface waters of the Far East of the Russian Federation. The insignificant distribution pattern between heavy and light REE, a negative Ce and Dy anomalies and a positive Eu anomaly were found. It was discovered the selectivity of the REY biosorption by the Gram-positive and Gram-negative bacteria and the time response of the biosorption process in a more acid environment.