Home – Home – Jornals – Chemistry for Sustainable Development 2023 number 2

The issues of climate warming and permafrost thawing are considered. A procedure for assessing the Arctic landscapes thawing based on the calculation of the normalized differential snow index (NDSI) is proposed. The factual material over the data of the global permafrost monitoring network is presented. Monitoring studies have shown that according to the results of NDSI calculation, abnormally early snowmelt was detected in 5 cases out of 23 years of observation at the Urengoy meteorological station and in 4 cases out of 23 years at the Tarko-Sale meteorological station. The absence of snow was observed during the indicated period in 13 cases at the technogenic sites of the Urengoy field, and in 8 cases at the Tarko-Sale field. With early snowmelt, the snow index NDSI decreases, and the depth of the seasonally thawed layer increases at the sites of the Urengoy field. The NDSI index can be used directly in assessing the duration of snow cover and early snowmelt, and indirectly in studying the depth of seasonally thawed layer. The results obtained are important for predictive estimates of the rate and extent of thawing and permafrost deformation, and for the prevention of emergency situations in the oil and gas complex.

To enhance oil recovery and intensify the development of fields with hard-to-recover reserves, including the deposits of high-viscosity oils, acid oil-displacing compositions with prolonged action have been developed on the principles of green chemistry using the method of deep eutectic solvents (DES). These compositions are based on surfactants and an adduct of inorganic acid, polyol and carbamide. As a result of experimental studies of acid-base equilibria in three-component systems with donor-acceptor interactions “boric acid - carbamide - polyol (glycerol, pentaerythritol)”, which are DES, the optimal compositions and concentration ranges of the components in acid compositions were determined. The results of laboratory studies and pilot tests of enhanced oil recovery technology with the use of acid compositions are presented. The compositions are compatible with mineralized formation waters, have a low freezing point ((-20)-(-50) °С) or a solid commodity form, low interfacial tension at the boundary with oil, are applicable in a wide temperature range (from 10 to 200 °C), provide effective oil displacement and prolonged impact on the formation. The acid GBA composition showed high efficiency under field conditions during pilot work in the experimental areas of the Permian-Carboniferous deposit of high-viscosity oil of the Usinsk oil field, developed under natural conditions and under thermal steam exposure, and was recommended for industrial use. The technology is environmentally friendly and technologically efficient. The industrial use of technologies for enhanced oil recovery and intensification of oil production is promising, which will make it possible to extend the profitable operation of fields at a late stage of development, to involve the fields with hard-to-recover oil reserves into development, in particular the deposits of high-viscosity oils, in a wide range of climatic conditions, including the northern regions and the Arctic.

The results of a comparative gas chromatographic - mass spectrometric (GC-MS) analysis of the composition of saturated and aromatic hydrocarbons, as well as heteroorganic compounds in petroleum oils isolated from a number of crude oils and natural bitumens, before and after selective chemical cleavage (chemolysis) of C-S and C-O bonds of sulphide and ether/ester bridges, respectively, are presented. The revealed difference in the structural-group and molecular composition of some types of compounds before and after chemolysis indicates that alkanes, alkyltrimethylbenzenes, naphthalenes, phenanthrenes, tetra- and pentacyclic aromatic hydrocarbons, and dibenzothiophenes are present in oils not only as molecular entities, but, partially, as structural fragments linked via sulphide and ether/ester bridges with other fragments in complex high-molecular entities. Ester-bound high-molecular С₂₀-С₃₀ homologues predominate among the bound alkanes. The proportion of C₁₃-C₁₆ homologues among alkyltrimethylbenzenes decreases after chemolysis. Chemolysis is accompanied by an increase in the proportion of С₃-С₄ naphthalenes in petroleum oils. The ratio of homologues among phenanthrenes changes after chemolysis: as a rule, the unsubstituted compound predominates over homologues. The ratio of fluoranthene and pyrene to benzanthracene and chrysene increases among tetracyclic aromatic hydrocarbons. The main trend in the changes in the composition of dibenzothiophenes after chemolysis is a sharp decrease in the proportion of unsubstituted homologue.

New methods of zeolite HZSM-5 modification with bismuth compounds are proposed. The choice of bismuth as a modifying agent is due to the systematisation and generalisation of the available literature data and experimental results of studying the chemistry and synthesis of bismuth compounds of various compositions. Phases in the resulting bismuth-containing zeolite systems were identified by X-ray phase analysis, and the state of bismuth in chemical compounds was determined. The number and strength of acid sites in the original and modified samples were determined by the method of temperature-programmed desorption of ammonia. The catalytic activity of zeolites was studied in the process of hydrogen-free processing of straight-run gasoline fraction of oil into high-octane gasolines. The effect of modification methods and process temperature on the structural-group hydrocarbon composition, the yield of gaseous and liquid reaction products was studied, and the octane numbers of the resulting gasolines were determined. It is shown that over the bismuth-containing zeolite catalysts, in comparison with unmodified zeolite, the yield of the target product, high-octane gasoline containing a smaller amount of aromatic hydrocarbons, increases, which makes it more environmentally friendly. It has been established that the production of high-octane gasolines that meet modern requirements for motor fuels is possible over modified zeolites within a wider process temperature range. Based on the studies performed, Methods for modifying the HZSM-5 zeolite with bismuth are proposed on the basis of the studies performed. The proposed methods make it possible to improve the efficiency of the catalyst in the process of upgrading the straight-run gasoline fraction of oil.

The content and composition of organic compounds in the bottom sediments of rivers and in soils sampled at the Arctic territory affected by diesel fuel spill were studied by gas chromatography-mass spectrometry. The composition of diesel fuel was studied. It was found that the groups of compounds characteristic of diesel fuel - n -alkanes, polycyclic aromatic hydrocarbons, alkylbenzenes and trimethylalkylbenzenes, sesquiterpanes, steranes, and hopanes were found mainly in the samples taken downstream at a distance of 0.5-20 km from the pollution source. The highest concentration of identified compounds was detected in bottom sediments and soil sampled at a distance of 20 km from the spill, which is associated with the structural features of the riverbed and bank line. In the samples taken at more remote sites (40-90 km), the traces of diesel fuel components were found only in bottom sediments.

Citrate complexes of transition metals, namely cobalt and molybdenum, used as active components in the synthesis of catalytic systems supported on alumina for hydrotreatment of heavy oil fractions have been studied. Cobalt nitrate hexahydrate and polyoxomolybdate (molybdenum blue) obtained by mechanical activation of molybdenum disulphide (MoS₂) powder were used as initial compounds. Thermogravimetric analysis of the samples was carried out during their heating from 25 to 750°C at a rate of 15°C/min in air. A study by thermogravimetric analysis shows that the order in which the active components are introduced significantly affects the thermal stability of the sample. Despite the general similarity of the profiles, a shift of the temperature range of citrate complex decomposition is observed, depending on the order of active components introduction. Presumably, this may be due to the different degrees of Mo and Co availability for the formation of compounds with citrate ligands. It is shown that the most thermally stable system is the one in which the Co-containing component and citric acid are introduced first, and then the alcohol solution of molybdenum blue; the least stable system is the reverse one, in which the alcohol solution of molybdenum blue is introduced first, then citric acid and the Co-containing component are added.

The composition and distribution of organic compounds in the bottom sediments of the Tom River near the city of Yurga (the Kemerovo Region - Kuzbass) in 1995, 2005 and 2018 are determined by gas chromatography - mass spectrometry. The compounds included hydrocarbons ( n -alkanes, isoalkanes, naphthenes, alkylbenzenes, and polycyclic aromatic hydrocarbons), oxygen-containing compounds (carboxylic acids and their ethyl and propyl esters). The data on the group composition of the most dangerous pollutants, polycyclic aromatic hydrocarbons, are presented. The pattern of changes in the technogenic load on the river system made by the Kuzbass enterprises over different years has been established. The highest contribution into the pollution of the Tom basin was determined to be in 2005. This contribution is directly due to the industrial activities at the enterprises of Kuzbass.

The process of removing sulphur-containing compounds from the diesel fraction has been carried out and investigated. The systems based on coordinating polar solvents (DMF and DMSO) and metal salts (CuCl₂, CoCl₂, MnCl₂, Mn(TFA)₂, Cu(TFA)₂) were used as extractants. It has been established that the presence of metal salts in extraction systems increases the degree of removal of sulphur-containing compounds from the diesel fraction from 11 to 49 % and reduces the content of polycyclic aromatic hydrocarbons by 33 %. It is assumed that the addition of metal salts to the solvent enhances its acceptor properties, which is manifested in the enhancement of its extractability.

The results of rheokinetic measurements of changes in the fluidity of gel-forming compositions of various natures obtained by the methods of rotational and selection viscometry are presented. A technique for processing measurement results obtained by means of vibrational viscometry in measuring vessels of different sizes has been developed. Two directions of the interpretation of nonmonotonic rheokinetic dependences are considered.

Investigation of the dispersed organic matter of the rocks at the Ust’-Maiskaya wildcat area was carried out. The data on the features of dispersed organic matter composition in the range of 2868.731 - 3057.68 m are presented. Alkanes, mono-, bi-, tri-, tetra- and pentacyclic arenes, bi-, tri-, tetra- and pentacyclanes, tetracyclic naphthenoaromatic hydrocarbons, dibenzothiophenes have been identified among hydrocarbons studied by means of gas chromatography - mass-spectrometry. Perylene and traces of nickel metalloporphyrins were also determined spectrophotometrically. It is shown that the initial organic matter was formed under the conditions of reduction and suboxidation, with a significant contribution from both the terrestrial vegetation and phytoplankton. The presence of nickel porphyrin and perylene complexes in some sections of the log suggests the shallowness of the sedimentation basin and the proximity of the coastline during the period of OM accumulation. The calculated vitrinite reflectance indicates that the differences observed for the MK₂ stage of catagenesis correspond to the main zone of oil generation.

The composition of cracking products of high-sulphur shale oil from the Kashpir deposit is investigated under different process conditions (duration and temperature). The characteristic features of the influence of heat treatment conditions on changes in the composition of liquid products of oil shale cracking are established. It is shown that the cracking of oil shale organic matter is accompanied by the formation of a wide range of low-molecular sulphur-containing compounds that enter the composition of oils. The changes in the group composition of sulphur-containing compounds of oils have been studied, the features of the distribution of thiophene derivatives, benzo- and dibenzothiophene derivatives in the composition of liquid cracking products are revealed. It is shown that the depth and rate of destruction of sulphur-containing structural fragments of kerogen is significantly affected by the temperature and duration of the process. The data obtained will improve understanding of the patterns of thermal transformations of sulphur-containing structural fragments of organic matter in high-sulphur oil shale during cracking.

Results of the application of benzene oxidation product (BOP), formed in barrier discharge, as an improving component of the inhibiting additive for paraffinic and highly paraffinic petroleum are presented. The proposed additive consists of a copolymer of alkyl acrylates with dodecylamine acrylate and BOP at a ratio of 15:1 wt. %. Benzene oxidation by air in a barrier discharge proceeds predominantly to phenol (~77.3 wt. %), diatomic phenols, and an insignificant amount of macromolecular compounds. The effect of the additive (in combination with BOP) in the amount of 0.03-0.05 wt. was evaluated relying on changes in the rheological characteristics and freezing point of paraffinic and highly paraffinic petroleum with a high content of resins and asphaltene components. The composition containing polymer and BOP additionally reduces the amount of asphaltene-resin-paraffin deposits by 1.5-2.5 g, which gives an increase in inhibitory capacity by 10-12 %. The depression of the freezing point of petroleum is 46 ºС on average. The dynamic viscosity of petroleum under study decreases in the presence of the additive by a factor of 2.2 on average.

A new multifunctional oil-displacing MIСA composition has been developed by the researchers of the IPC SB RAS for the purpose of oil recovery enhancement. The MIСA composition possesses oil-cleaning properties and is able to align the displacement front by increasing the reservoir sweep. Laboratory tests of MICA and its components (glycerol, carbamide, and boric acid) were carried out against the reservoir microflora of three groups: hydrocarbon-oxidising and denitrifying bacteria (HOB and DNB, respectively) as possible agents for enhanced oil recovery, and sulphate-reducing bacteria (SRB), as a corrosion-dangerous group. It is shown that HOB exhibited positive reactions to all versions of components introduction, as well as to the solutions of the composition diluted by a factor of 20-50. The presence of boric acid, in particular in the binary systems with carbamide and glycerol, suppressed the growth of DNB in spite of the stimulating action of glycerol and carbamide. The multifunctional MICA composition had a positive effect on the DNB count at 20-50 dilution. In the course of pilot work in 2020-2021 at the Usinskoye oilfield, a positive effect of the MICA composition on the growth of HOB and DNB groups and the inhibition of the SRB count was revealed. The effect decreased after 8-10 months due to manifold dilution of the composition and its displacement. This action of MICA and its components may be evaluated by two positive effects: an increase in the counts of HOB and DNB, as potential agents of oil displacement, and inhibition of the activity of SRB, as an agent of sulphide corrosion of equipment.

Changes in the composition of SARA fractions (Saturated, Aromatics, Resins, Asphaltenes) of methane crude oil from the Zyuzeevo oilfield (the Republic of Tatarstan) during thermal cracking are investigated. Cracking was carried out at 450 °C for 120 min in the isothermal mode. The data on mass balance, the composition of liquid and gaseous products of cracking were obtained. It is shown that the composition of hydrocarbons in liquid products and the yield of side gaseous and solid products depend on the composition of initial SARA fractions. Thus, the yield of solids is maximal from asphaltene fraction cracking, while the largest amount of gases are formed from resin fraction cracking. It has been established that cracking of SARA fractions involves the formation of new components that were absent in the initial feedstock. It is shown that the structural features of initial resin and asphaltene molecules affect the content and composition of their cracking products.

The state of the vegetation cover at six hydrocarbon fields of the Parabel district of the Tomsk Region has been studied relying on satellite data. An example of the practical application of the procedure developed for the quantitative assessment of the state of vegetation cover at oil-and-gas producing territories on the basis of the values of vegetation indices obtained using the satellite data MODIS (Moderate Resolution Imaging Spectroradiometer) is shown. It is established that changes in the values of vegetation index EVI (Enhanced Vegetation Index) over the 12-year period (2011-2022) have a positive trend, with the maximum values recorded in 2020. This may indicate the restoration of vegetation and improvement of the environmental situation.

The physicochemical properties of hard-to-recover viscous oil with high paraffin content were evaluated relying on the analysis of information from the oil characteristics database, compiled at the Institute of Petroleum Chemistry SB RAS. It is established that Russia is distinguished by the largest reserves of viscous paraffin oil (VPO) on the territory of Eurasia, where almost three quarters of the reserves are concentrated in the Volga-Ural oil and gas basin. The characteristics of the properties of these oils under various conditions of their occurrence have been analysed. It is shown that VPO is more confined to terrigenous rocks, in which the reserves are 4.6 times greater than those in carbonate formations. The physicochemical properties of VPO in the productive formations differing from each other in permeability and porosity are considered. It is established that in the case of high permeability of formations, the density of VPO increases (oil becomes heavier), coking ability, sulphur and resin content grow, the content of paraffins and the gas factor decrease. Viscous paraffin oils in reservoirs with different permeability have a positive pour point and are characterized by low gas content. In medium- and highly porous formations, VPOs are heavy, sulphurous, medium-resinous and medium-asphaltene, with low gas content. It is shown that in highly permeable and highly porous reservoirs, the content of paraffins in VPO is minimal, and, quite contrary, the content of paraffins in oil is the greatest in low-permeable and low-porous reservoirs. The properties of high-hardening VPOs are revealed, which significantly differ from the properties of oils with a negative pour point. High-setting VPOs differ from low-setting oils by medium density (low-setting oils are heavy), but very high viscosity; higher content of paraffins and oxygen, but lower content of resins, asphaltenes, sulphur (almost 2 times) and nitrogen; the gas factor is higher by 81 %.

The morphology and structure of the mesophase in the series: coal tar pitch (CTP) - α-fraction of CTP - carbonised α-fraction after heating to 1200 °C, were studied by scanning electron microscopy, X-ray phase and X-ray structural analysis. The X-ray structural parameters were determined: longitudinal and transverse dimensions of the lamellae and the thickness of packages, the distance between the lamellae and the number of lamellae in the formed packages. It is shown that the two-dimensional structures of the carbon mesophase are ordered into three-dimensional packages during the formation of semi-coke under CTP heating. It is established that the carbon structure of CTP and its α-fraction is represented by the turbostratic and graphite-like phases. The sizes of the packages formed by the lamellae during structuring in the transverse direction in the studied samples are of the order of 18-25 Å, in the longitudinal direction 46-63 Å, the average distance between the lamellae in the studied samples is 3.46-3.52 Å.