The investigation of bitumen occurrences confined to zones of hydrothermal alteration developed within volcanic rocks of the Late Permian-Early Triassic age, intersected by a well in the upper part of the pre-Jurassic basement section at the Litvakovskoye oil field, is of critical importance for predicting the petroleum potential of the West Siberian basement. The presence of bitumen in metasomatically altered basalts provides evidence of either a destroyed oil accumulation or the existence of hydrocarbon migration pathways within the pre-Jurassic complex. According to mineralogical and petrographic data, hydrocarbon emplacement occurred after the hydrothermal-metasomatic alteration of the volcanic rocks. Based on V.A.Uspensky's classification, the studied bitumens are identified as pure asphaltites and transitional asphaltite - kerite varieties. Molecular composition and carbon isotope data suggest that the precursor source organic matter of the naphthides was formed under reducing conditions in a shallow basin with elevated water salinity and clay - carbonate sedimentation, which may have received humic material input. The level of thermocatalytic transformation of the bitumens corresponds to the early phase of the oil window. The naphthides have been variably affected by hypergenic and, possibly, migrational processes. In addition to the typical biodegradation markers - C-28-C-34 25-norhopanes - the bitumens reveal, for the first time, their lighter homologs: demethylated tricyclic C-19 and tetracyclic C-23 terpanes, as well as unusual tetracyclic hydrocarbons of the hopanoid type (secohopanes C-27, C-29, C-30). These compounds, along with bicyclic terpanes C-17-C-24, may be considered a distinctive feature of the solid naphthides from the pre-Jurassic complex of the study area. The bitumens are characterized by low sterane content and exhibit specific compositional features similar to those of crude oils from the Kotyg'yeganskoye and Severo-Khokhryakovskoye oil fields. The distribution of tri- and tetracyclic terpanes indicates a similarity between the bitumens and both crude oils and bitumoids of the Tyumen Formation. The observed sterane and terpane signatures in the bitumens may be attributed to the contribution of humic material to the precursor source organic matter and suggest a possible genetic link between the naphthides and the deposits of the Tyumen Formation.
The global volume of natural gas trapped in hydrate deposits far exceeds the conventionally recoverable hydrocarbon reserves. However, the high costs associated with hydrate production, transportation, and storage currently hinder the large-scale implementation of hydrate-based technologies. A promising way to reduce these costs is through phase transition technology, which involves & Scy;& Ncy;(4) hydrate depressurization in the presence of biosurfactants, followed by & Scy;& Ocy;(2) formation. This approach also enables carbon dioxide sequestration, addressing the corresponding environmental concerns. Biosurfactants, which are naturally present in many hydrate reservoirs, enhance hydrate growth and accelerate & Scy;& Ncy;(4)-& Scy;& Ocy;(2) exchange. The newly developed method of producing highly porous ice using biosurfactants, presented in this research, provides higher formation rates, substantially reducing the time required for the process. Most importantly, this technique eliminates the risk of mixed hydrate formation-a major limitation, which hindered the replacement efficiency. As a result, the proposed sequential phase transition method decreases the total time of CO2 hydrate synthesis by two to three orders of magnitude compared to direct & Scy;& Ncy;(4)-& Scy;& Ocy;(2) replacement. The method is particularly effective for permafrost regions and offers a more environmentally friendly approach to developing gas hydrate deposits by minimizing methane emissions while enabling CO2 storage.
The work investigates the influence of seasonal changes in the composition of fresh water on the rheological properties of guar-borate hydraulic fracturing fluids. Between October 2024 and August 2025, monthly samples were taken from three sources in the Republic of Tatarstan, with analysis of pH (7.3-7.9), alkalinity (73-275 mg/l HCO3-), total hardness (180-520 mg/l Ca2++ Mg2+), chlorides (42-284 mg/l), sulphates (61-146 mg/l), and iron ions (0.1-0.3 mg/l). Fracturing fluids were prepared using these waters and tested on a Brookfield PVS high-pressure rheometer at 32 degrees C in accordance with ISO 3219:1993. The target viscosity range was approximately 400-700 mPa.s. We found that in water with high salinity (source N 2, average hardness similar to 419 mg/l, Cl->180 mg/l), gel viscosity decreased by 10-15 %, the time to recover to operating viscosity increased, and breakdown accelerated, which raised the risk of premature proppant settling. Correlation analysis showed strong positive correlations between hardness, chlorides, sulphates, and alkalinity (r = 0.53-0.90) for "soft" sources N 1 and 3, whereas in the mineralized water of source N 2 these correlations are weakened (r = 0.17-0.51). The results demonstrate that the seasonal increase in salinity (winter-spring period) significantly impairs the rheological stability of hydraulic fracturing fluids and emphasize the need for mandatory monitoring of water composition and adaptation of formulations during periods of peak salinity.
The hazard of rock bursts at the Khibiny deposits is largely due to their block structure and the natural gravitational-tectonic stress field in the rock mass. A detailed analysis of documented cases of rock bursts in the fields of the Kola Peninsula allowed to develop a classification of geodynamic events by the mechanism of their occurrence. During the analysis, it was found that in the period 1980-2024, 40 % of all rock bursts were associated with geological disturbances with high strength of the aggregate material. Such geodynamic events occur as a result of activation of a combined mechanism. The cause of the geodynamic event in this case is a combination of structural disturbances of the rock mass with a high level of tectonic stresses. An important criterion of rock burst hazard in the area of geological disturbances in highly stressed rock masses is their relative rigidity, and consequently, the degree of fracturing in relation to the natural conditions of the rock mass. The mechanism of this class of rock bursts can be described within the framework of the theory of rigid-platen theory. Based on the research results, the need to pay serious attention to the development of special measures to prevent or minimize the risk of geodynamic events when approaching tectonic disturbances with high strength of the aggregate material of the stoping and development workings is justified.
Wastes from mining and ore processing have a negative impact not only on surface- and groundwater, soils, but also on the state of the ground-level atmosphere. In highly permeable deposits of waste storage facilities, as a result of weathering of ores and rocks hosting mineralization, highly mineralized waters containing metals are formed. Under their influence, liquid aerosol flows are formed above the storage facilities. Their conditions of formation and chemical composition are still poorly studied. The objective of the work is to determine the qualitative and quantitative composition of toxic metals entering the ground-level atmosphere as part of aerosols from the storage facility of oxidized ores and overburden rocks stockpiled during the development of the Ozernoye polymetallic deposit. The tasks set are to identify the mechanism of aerosol flow formation from the aeration zone of storage facilities, to develop a methodology for sampling aerosols by condensing them, and to collect the amount of condensate required for analysis. The collected condensate samples were analysed by inductively coupled plasma mass spectrometry using Agilent 7500ce quadrupole mass spectrometer according to a certified procedure. We found that the total mineralization of condensation waters reaches 110-130 mg/dm3. The content of toxic elements (mercury, lead, zinc, copper) is several times higher than the concentration in surface waters of the area. In the snow cover in the area adjacent to the Mining and Processing Plant, manganese, zinc, copper, and mercury were found in abnormally high concentrations exceeding the MPC for fishery purposes. Their input into the snow cover is associated with evaporation from the surface of stockpiled wastes and transport of pollutants by air currents. The work shows that liquid aerosols containing high concentrations of toxic chemical elements are released into the atmosphere from the stockpile of oxidized ores and overburden rocks. To protect the natural environment, the enterprise needs measures to isolate stockpiled mining wastes from weathering agents and prevent aerosol input into the atmosphere, as well as to use personal protective equipment for personnel working with mining and processing wastes.
