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Relevance. The ability to provide more accurate and efficient assessment and management of hydrocarbon production using software products for integrated field modeling. However, this approach requires an analysis of the source data quality, as well as the selection of the correct approach to creating models. Consistent and systematic work makes it possible to reproduce the actual situation with high accuracy in order to use the results obtained in further work. The integrated field model is a completely new approach to field development, when current work is based not on existing solutions, but on potential. Forecasting the behavior of the reservoir, wells and infrastructure, the collection system and the system for maintaining reservoir pressure allows for a comprehensive assessment of the possibilities of obtaining maximum oil and gas production while minimizing possible losses. Aim. Formation and analysis of an approach to setting up PVT-models of fluids, models of injection well stock, collection and transport systems and reservoir pressure maintenance systems by adapting parameters to actual data. Methods. Setting up and adapting injection well models; setting up and adapting collection system and pipeline models; approach to work with the reservoir pressure maintenance system. Results. The results obtained make it possible to adapt the components of the integrated model with an accuracy of over 95 %, which makes it possible to simulate the operating conditions of the field. Because of the analysis, tuning criteria were identified, and the minimum required set of parameters for high-quality adaptation of models was presented. Efficiency and accuracy of predictive calculations on adapted models has also been proven by comparing actual performance data with synthetic data. Based on the work done, we can conclude that the use of an integrated model shows us a high convergence with real data, which allows us to optimally approach the field development regime.

The results of experimental studies of deformation problems in pipeconcrete specimens with small cross sections are provided and analyzed. The stress-strain state of a steel pipe and a pipe filled with concrete is studied and compared. Experimental determination of the dependencies between axial load and deformations of pipe-concrete and steel bars, as well as evaluation of concrete’s and steel pipe’s contribution to the total load-bearing capacity of the composite section are provided. Tests were carried out for short pipe-concrete specimens with the pipe dimensions equal to 60x2, 76x3 and 102x3.5, as well as for hollow steel pipes with the corresponding dimensions. The diagrams of deformation were obtained basing on the experimental results. The deformation of the pipe-concrete element under central compression occurs in proportion to the deformation of a hollow steel element with the same diameter, that made it possible to evaluate the contribution of concrete to the work of the pipe-concrete cross-section, which turned out to be constant at each stage of deformation. A methodology has been proposed that enables to describe analytically the deformability of pipe-concrete elements under axial compression by means of the analytical model based on the experimental data.

Relevance. Current situation, when an increasing number of subsoil users are moving towards the correct choice of a development system. Therefore, the applicability of integrated asset models is growing exponentially every year. One of the integrated approaches in the field of reservoir–well–ground infrastructure modeling is the use of Petroleum Experts software. This solution has successfully established itself in the international market due to the presence of a large number of various correlations suitable for certain geological conditions, as well as a complex methodology for calculating the tasks. Thanks to the above product, the tasks of calculating the inflow from a reservoir, well flow rate and infrastructure throughput analysis formed a single integrated solution for high-quality modeling of fields/groups of fields. In its turn, the Petroleum Experts Prosper software allows you to evaluate the efficiency of a well, as well as to obtain additional production through optimization calculations on a well model tuned to actual parameters. Aim. To form and analyze the approach to setting up component models (wells) by adapting parameters to actual data in order to obtain additional oil production. Methods. Setting up and adaptation of well models equipped with installations of electrical center pumps, setting up and adaptation of fountain wells, approach to working with a periodical fund, assessment of the effectiveness of the use of Prosper in terms of additional oil production. Results. The results obtained allow us to adapt well models with an accuracy of more than 95%, which simulates the operating mode of the mechanized and fountain mining fund in order to optimize and increase oil production. As a result of the analysis, the criteria for tuning wells were identified, and the minimum necessary set of parameters for high-quality adaptation of models was presented. The effectiveness and accuracy of the method by comparing the actual data on the regimes of the wells with synthetic are also proved. Based on the work done, we can conclude that the use of an integrated model shows us a high convergence with real data, which allows you to conduct optimization calculations with high accuracy with obtaining a result that provides the greatest effect.

Relevance. Modern approach to development of oil and gas fields. Digitalization and automation of hydrocarbon production allow not only to reducing the response time to possible deviations from the operating level of production, but also quickly making decisions on its further normalization. The use of modern software to create a reservoir model using the material balance method allows you to calculate current and predicted reservoir pressures depending on the amount of selected and injected fluid. With high-quality adaptation, the integration of the reservoir model, wells and collection system, in its turn, allows you to correctly approach the choice of a field development system, as well as correctly assess the possible potential of the field. Forecast calculations performed on an integrated model can form the basis for budget planning, as well as the basis for carrying out geological and technical activities on wells, commissioning new wells, and modernizing equipment and infrastructure. Moreover, group optimization calculation allows us to maximize additional oil production, taking into account all geological and technical constraints. Aim. Formation and analysis of an approach to setting up a reservoir model by adapting parameters using the material balance method; formation of a solution for adapting the integrated model, reconciliation of the results with actual data; carrying out an optimization calculation and obtaining additional oil production. Methods. Adjustment and adaptation of reservoir models using the material balance method; adjustment and adaptation of the integrated model of a field/group of fields; calculation of the forecast for a period of 30/90 days; optimization calculations. Results. The obtained results make it possible to adapt the components of the integrated model with an accuracy of ±5 %, which makes it possible to simulate the operating mode of the field. As a result of the analysis, tuning criteria were identified, and the minimum required set of parameters for a qualitative adaptation of the reservoir model and the collection system was presented. The effectiveness and accuracy of the tool are also proven by comparing actual data on operating modes with synthetic ones. Based on the work done, it can be concluded that the use of the integrated model shows us a high convergence with real data, which allows us to optimally approach the field development mode. Moreover, an optimization calculation was carried out to obtain additional oil production using the proposed solution, and a forecast for oil production for a period of 90 days was calculated, which was later confirmed when compared with actual data.

Relevance. The extraction of natural and associated petroleum gases is accompanied by the necessary gas preparation for delivery to the consumer for commercial use. In particular, in gas and oil fields, the separation of all side homologues of methane, moisture and other non-hydrocarbon compounds that are part of associated petroleum gases, which worsen the operating conditions of equipment and lower the quality of the feedstock, are used. With the ever-increasing degree of water cut in gas and oil fields, it is necessary to progressively develop technological methods for gas treatment, including one of the most common in the Russian Federation – the absorption method of drying natural and associated petroleum gases from water impurities. Purpose: to substantiate the use of diethylene glycol in preparation of natural gas, as the most effective absorbent in the Far North. Object: complex natural gas treatment unit. Method. The calculation of the model of the complex gas treatment unit was carried out in the UniSim Design R470 software package. Results. The influence of the main technological parameters: temperature, pressure of absorption drying of natural gas on the absorbent diethylene glycol at the gas treatment plant for the removal of water impurities is investigated. The optimal pressure and temperature conditions for effective removal of moisture from natural gas by the method of water absorption by diethylene glycol at high pressure of the input raw material are determined. It is shown that the use of diethylene glycol absorbent is most effective in the conditions of the Far North. When diethylene glycol is used as an absorbent for drying natural gas from water at low temperatures, the energy consumption for gas compression, its cooling in front of the absorber, and the consumption of the dryer are significantly reduced compared to other absorbents. The most effective technological parameters of the operation of an absorption plant for drying natural gas at a diethylenglykol concentration of 98 % wt. and raw natural gas consumption of 385 thousand m³/h were determined. Diethylenglykol already at a contact temperature of 19 °C dries the gas to the regulated dew point temperature of minus 20 °C and pressure in the gas treatment unit of at least 4 MPa and above. On the contrary, exceeding the gas–diethylenglykol contact temperature above 20 °С and lowering the pressure below 4 MPa lead to a significant increase in energy consumption, the entrainment of the diethylene glycol absorbent and the deterioration of the economic indicators of the natural gas drying from water impurities.

Link for citation: Korotkov R.N., Konovalov A.A., Ovcharenko D.M., Erofeev V.I. Binary mixture technology as a modern complex method of increasing oil recovery for the development of hard-to-recover reserves in the fields of Western Siberia. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 146-153. In Rus. The relevance of the study is caused by the current situation, when subsoil users are trying to extract the maximum amount of oil in a short time, as a result of which the development system is mainly compiled incorrectly, the share of hard-to-recover reserves is growing every year. Therefore, there is an urgent need to develop residual reserves from the subsoil, which are often difficult to recover. One of the complex reservoir stimulation is thermal-gas-chemical stimulation, which is a method of extensive reservoir stimulation and describes a promising technology among other existing methods for enhanced oil recovery. Binary mixtures, in their turn, will increase oil recovery by an average of 5–10 %. Purpose: to study the effectiveness of the application of binary systems technology in order to increase oil recovery from reservoirs containing hard-to-recover hydrocarbon reserves. Methods: systematization of classification approaches in terms of hard-to-recover reserves, selection of the most relevant methods of enhanced oil recovery according to the efficiency criterion, analysis of Russian and foreign experience in the use of thermal-gas-chemical treatment, assessment of the technological and economic feasibility of using binary mixtures in analogous fields. Results. The use of binary mixtures makes it possible to increase oil recovery by 5–10 % on average. The principles of oil displacement using ammonium nitrate and the decomposition reaction product were studied, an analysis of pilot industrial tests both in Russia and abroad was reproduced, and current issues were studied. Various fields are also considered, which have already proved the positive dynamics of the development potential when using this technology. A preliminary assessment of the economic efficiency of thermal-gas-chemical treatment in the current state of the gas and oil industry in comparison with other methods of enhanced oil recovery is presented.

The relevance. In recent years, in addition to the direct extraction of natural or associated petroleum gases from the subsoil, it is necessary to prepare them, ensure commercial quality, in particular, remove moisture, higher C2+ hydrocarbons and other by-product gases that adversely affect the technical and economic performance of plants and contribute to the formation of crystalline hydrates. Due to the high quality requirements for treated natural gas and moisture content growth to increase the profitability of production, gas treatment technologies are constantly being improved and updated, including the absorption method of natural gas drying. Purpose: to substantiate the effectiveness of the use of triethylene glycol as an absorbent in preparation of natural gas by the absorption method at the existing integrated natural gas treatment plant. Object: complex natural gas treatment unit. Method: simulation of moisture absorption from natural gas in the UniSim Design software package. Results. The influence of pressure and temperature, two absorbents: diethylene glycol and triethylene glycol, on the efficiency of gas treatment on the model of a natural gas treatment plant, an operating gas field, has been studied. The optimal temperature and pressure are selected, at which moisture absorption from gas will most effectively take place at decreasing pressure of the input raw material. It is shown that when triethylene glycol is used as an absorbent, the energy consumption for gas compression, its cooling before the absorber, and the consumption of the desiccant are significantly reduced compared to diethylene glycol.

The relevance. In recent years, due to the severe depletion of oil and gas fields, there is an urgent need to create new highly efficient technologies to increase oil and gas production both in oil and gas fields. Most of these fields are at the last stages of development, which are characterized by falling reservoir pressure, high water cut, a large amount of mechanical impurities and moisture in the produced hydrocarbon feedstock. As a result, there is an urgent need to develop new processes and improve technologies for field preparation of natural gas. Purpose: analysis of modern industrial processes of natural gas preparation: absorption and adsorption purification of natural gas from water, low-temperature separation, supersonic gas separation technology; choice of the most cost-effective and reliable process and technology for natural gas deep purification from water impurities in the conditions of industrial operation of gas and oil fields of the Russian Federation based on the analysis of technologies. Results. The analysis of industrial processes and methods of drying natural gas: absorption and adsorption drying, low-temperature separation and technology of supersonic separation of gas from moisture content and mechanical impurities, is carried out. The features of these processes, their properties, technological schemes, solutions, as well as advantages and disadvantages are analyzed. It was established that the use of natural gas absorption drying from water impurities makes it possible to obtain dried gas to a water dew point temperature of up to –20 °C. The introduction of the technology of natural gas adsorption drying from water impurities makes it possible to dry gas to a water dew point temperature in the range from –38 to –99 °C.

Link for citation: Liintin I.A., Erofeev V.I. Modernization of natural gas treatment. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 6, рр.126-133. In Rus. The relevance. Most of the existing fields in the Russian Federation are at the last stage of development. They are characterized by low wellhead pressures, increase in water cut, as well as a large amount of mechanical impurities. These factors have a detrimental effect on the technical and economic performance of the installations, as well as on the further transport of gas through the main gas pipelines. As a result, there is an urgent need to create new efficient technologies in the preparation of natural and associated petroleum gases. In addition to creating new technologies, it is possible to upgrade the existing well production facilities or change process parameters. The main aim: to modernize the current technological scheme of natural gas treatment. Object: complex gas treatment plants of gas fields. Method: modeling with a software package «UniSim Design». Results. It was calculated and shown how much of the hydrate formation inhibitor must be supplied to the gas pipeline during transportation from a cluster of gas wells to a complex gas treatment unit. The dew point temperatures were calculated before and after the upgrade of the inlet separator, as well as the percentage of moisture in natural gas before and after the upgrade of the gas treatment unit. If the wellhead and reservoir pressures drop significantly, it is necessary to carry out a general reconstruction of fields, prefabricated networks, it is possible to combine fields, install modular compressor stations, since the pressure and amount of gas for booster compressor stations will not be enough. In this regard, supersonic separation is the most promising method for separating and purifying gas condensate mixtures from moisture and acid gases. After replacing the separator with a 3S-separator in the complex natural gas purification unit, the dew point temperature of the commercial gas decreased. Gas pressure at the outlet of the 3S-separator has values corresponding to the process mode of absorber operation and the amount of separated moisture and liquid, in percentage terms, will increase.

The relevance. Today, the Russian Federation is increasing the pace of natural gas production by introducing new gas fields. But in addition to new ones, there are developed fields, most of which are at the last stage of development, that is, in a period of declining production. The gas produced from these fields is characterized by low reservoir pressures, high moisture content and mechanical impurities compared to the initial (design) values. The presence of moisture and mechanical impurities adversely affects its further processing and transportation. As a result, when reaching the required values of the industry standard, problems may arise during gas treatment by absorption or adsorption dehydration of natural gas, as well as problems associated with further gas transportation through pipelines. Therefore, the study and comparison of these two technological processes for natural gas preparation are relevant today, since many industrial gas production enterprises use these two processes of gas preparation. The main aim of the research is theoretical analysis of natural gas preparation by two typical processes: absorption and adsorption; selection of the most efficient and cost-effective processes from the point of view of industrial scale in the conditions of gas fields of oil and gas enterprises of the Russian Federation. Results. The authors carried out the review of two processes for drying natural gas by absorption and adsorption from moisture and mechanical impurities and considered the features of two processes, namely the properties of absorbents, adsorbents, typical schemes, foreign experience, as well as their advantages and disadvantages.

The relevance. Compared with conventional reservoir, offshore heavy oil reservoir faced the problem of lower water flooding recovery. It is helpful to improve the water flooding recovery of heavy oil reservoir if we have more knowledge about seepage characteristics of water and oil. The main aim of the research is to investigate the change rule of seepage characteristics of water phase and oil phase in offshore heavy oil reservoir, which is helpful to the decision of field construction and can provide guidance for numerical simulation. Methods. The reservoir geological characteristics, fluid properties and field construction technology of the destination offshore heavy oil reservoir in Bohai Oilfield were taken into consideration. The impact of core permeability, injection water washout and crude oil viscosity on relative permeability curve and displacement efficiency of water flooding were studied, through core displacement experiment using displacement method of unsteady state. The change of core inside structure is presented by core CT scanning and mercury pressure test. Results. With the increase of core permeability, water phase relative permeability increases, the swept volume of water phase becomes bigger, two-phase flow span gets wider, and ultimate recovery enhances. The function of «cleaning» and «erosion» that water washout exerts on core pore structure would enlarge the pore throat radius, increasing core permeability, and its influence on relative permeability curve and displacement efficiency is the same as the influence of permeability increase. With the crude oil viscosity increasing, mobility control ability of water gets weaker in the process of water flooding, displacement phase viscous fingering phenomenon aggravates, the swept volume of water phase becomes smaller, two-phase flow span gets narrower, and ultimate recovery decreases.

The relevance. Oil field Tuha is a medium and low permeability reservoir, with high salinity water. Currently, the water cut of the main productive layer in the «Y» section of the Tuha oil field is more than 93 %. Existing polymers and salt-resistant polymers cannot be well dissolved and distributed in layer water, and also have poor retention in the reservoir and profile control ability, hence, it is difficult to achieve a good technical and economic effect. So, it is important to investigate the method of profile management for effective oil displacement from reservoirs with high mineralization. The main aim of the research is to study oil displacement efficiency and optimization of parameters of inorganic profile agent based on sodium silicate for enhanced oil recovery. Methods. Viscosity of the studied samples was determined on a Brookfield DV-II viscometer; the experiments investigating the effect of the slug size of main agent, the number of cycles of alternative waterflooding, the injection speed of main agent and the injection of surfactant on the oil displacement efficiency were carried out on filtration unit. Results. In order to satisfy the demand of enhanced oil recovery at this oil field, the experimental studies were carried out to optimize parameters and increase the efficiency of oil displacement of the inorganic silicate profile control agent based on the geological characteristics of the reservoir and fluid properties of the «Y» sections. The results show that when the size of the slug of the main agent is from 0,06 to 0,08 Vinj/Vpore, and the cycle of alternative flooding is 5–6, the degree of using the layers with medium and low permeability is higher, the water cut decreases and oil recovery increases significantly. Compared to single silicate flooding, the combination of silicate and surfactants can achieve the goal of expanding the scope of coverage and improving the efficiency of oil displacement, and increases the oil recovery factor.

The relevance. Polymer flooding is widely used in practice in the development of oil fields. The high-concentration polymer solution has strong viscoelasticity, but with the increase in mass concentration of the polymer, the compatibility problem occurs between polymer molecules aggregate size and reservoir rock pore size during its practical application. Cr3 + polymer gel based on intramolecular cross-linking has a smaller aggregate size and good compatibility with the reservoir, so it is relevant to study the effect of gel formation of Cr3 + polymer gel and its influence factors. The main aim of the research is to study filtration and rheological properties of polyacrylamide-based aqueous gel with chromium acetate to enhance oil recovery. Methods: physical simulation of oil displacement and fluid filtration under reservoir conditions on a filtration unit, determination of viscosity of cross-linked polymer gel using the Brookfield DV-II viscometer, measuring the size of the molecular coil Dh in a Brookhaven BI-200SM light scattering system (Brookhaven Instruments Cop., USA), determination of viscoelasticity using the Harke10 rheometer. Results. Regulating the concentration of polymer, water solution salinity and the ratio of the polymer content and chromium (w(П/Cr3+)), one can obtain the Cr3+ polymer gel system based on intramolecular cross-linking with a smaller molecular aggregate and higher resistance confidence. After the reaction of intramolecular cross-linking of the polymer solution, on the one hand the viscoelasticity of the system is significantly improved and the oil displacement coefficient increased. On the other hand, the intramolecular crosslinking reaction reduces the flexibility of the polymer molecule aggregates, increases their rigidity, weaken their deformability in the process of passing through the pores, and enhance the retention ability in the high permeability layer. Cr3 + polymer gel system not only has good injectability, it can also gradually reach a higher injection pressure, so it enlarges sweep volume effectively. In total, it is shown that the oil recovery coefficient of the polymer gel system is higher than the polymer solution.

Relevance. In recent years, polymer flooding technologies have been widely used in exploitation of oil and gas fields, especially in the later stages of field development. However, when operating reservoirs with elevated temperature of more than 70–80 °C and a high degree of salinity of formation water, many polymeric oil-displacing agents undergo rapid degradation, which leads to decrease in the level of hydrocarbon production. In this regard, one of the important problems is the creation and development of thermo- and salt-resistant polymeric materials and compositions based on them to increase the production of hydrocarbons in the oil and gas fields. The main aim of the research is to investigate the effect of formation water salinity on the physicochemical and filtration characteristics of polymer solutions and gels to enhance oil recovery. Methods. Viscosity of the polymer solutions and polymer gel were determined on Brookfield DV-II viscometer; shape and size of the polymer particles and polymer gel were studied on Hitachi S-400N scanning electron microscope; polymer size of molecular tangle Dh was measured on a wide-angle dynamic/static light scattering system Brookhaven BI-200SM (Brookhaven Instruments Cop., USA); physical modeling of fluid filtration at reservoir conditions was carried out on the filtration unit; determination of viscoelasticity and rheological properties of polymer solutions and gels was studied using a rheometer Harke 10. Results. The degree of mineralization of formation water has a significant effect on the viscosity of polymer solutions. Due to the fact that calcium and magnesium ions were preliminarily removed in partially demineralized water, the polymers have good solubility and the ability to increase the viscosity of the solutions. With increasing concentration of displacing agent, the viscosity of the solutions increases. Destructive effects of salts of formation water on polymers cause a significant decrease in viscosity of solutions of displacing agents. Due to the high degree of mineralization of partially demineralized water, a large amount of sodium chloride ions surround the molecular skeleton of the polymer of the displacing agent. The macromolecules of polymer P-1 have a predominantly two-dimensional network structure. The macromolecules of polymers P-2 and P-3 have a predominantly spatial three-dimensional network structure, in which some polymer molecular chains are broken and the network structure of polymers is defective. Compared with polymer P-3, the three-dimensional network structure of the polymer molecular aggregate P-4 has a clearer spatial structure. Comparing the physico-chemical properties of polymers P-1, P-2 and P-3, it follows that the coefficient of resistance and the coefficient of residual resistance for polymer P-1 are greater than for polymers P-2 and P-3. This is due to the fact that the salt-resistant polymer P-1 forms aggregates of the network structure due to intermolecular association, which leads to poor compatibility with core pores, and the resistance coefficient and residual resistance coefficient for polymer P-4 are the greatest the polymer mixture underwent reactions of intramolecular crosslinking of polymer molecules and Cr3+ cations, which led to a significant increase in the retention of the polymer solution, filtration resistance, injection pressure and to enhance oil recovery.

The effect of modification of MFI zeolite 1–5 wt.% ZnO activated by plasma on acid and catalytic properties in the conversion of the propane–butane fraction into arenes was investigated. The high-silica zeolites with silicate module 45 were synthesized from alkaline alumina–silica gels in the presence of an ‘X-oil’ organic structure-forming additive. The modification of the zeolite with zinc was carried out by impregnating the zeolite granules in the H-form with an aqueous solution of Zn(NO3)2. The obtained zeolites were characterized by X-ray phase analysis and IR spectroscopy. It is shown that the synthesized zeolites belong to the high-silica MFI zeolites. The study of microporous zeolite-containing catalysts during the conversion of C3-C4 alkanes to aromatic hydrocarbons made it possible to establish that the highest yield of aromatic hydrocarbons is observed on zeolite catalysts modified with 1 and 3% ZnO and amount to 63.7 and 64.4% at 600 °C, respectively, which is 7.7–8.4% more than on the original zeolite. The preliminary activation of microporous zeolites modified with 1–5% ZnO and plasma leads to an increase in the yield of aromatic hydrocarbons from the propane–butane fraction; the maximum yield of arenes is observed in zeolite catalysts modified with 1 and 3% ZnO and activated by plasma, amounting to 64.9 and 65.5% at 600 °C, respectively, which is 8.9–9.5% more than on the initial zeolite. The activity of the zeolite catalysts modified by ZnO and activated by plasma show good agreement with their acid properties. Activation of the zeolites modified by 1 and 3% ZnO and plasma leads to an increase in the concentration of the weak acid sites of the catalyst to 707 and 764 mmol/g in comparison with plasma-inactivated 1 and 3% ZnO/ZKE-XM catalysts at 626 and 572 mmol/g, respectively.

The acid and catalytic properties of the modified MFI zeolite catalysts during the conversion of the propane–butane fraction of the associated petroleum gases into the aromatic hydrocarbons were studied. It was established that the high-silica zeolites synthesized with the new structure-forming additive of the alcohol fraction (ZKE-AF) belong to the high-silica MFI zeolites. The resulting zeolites were modified by 1–5 wt. % additives consisting of zinc oxide and sulfide. The influence of the modifying additive concentration containing zinc oxides and sulfides in an amount of 1–5% on the acid and catalytic properties of the catalysts in the conversion process of lower C3–C4 alkanes into liquid hydrocarbons was studied. The research of the acid properties of the modified zeolite catalysts by thermal desorption of ammonia showed that the total concentrations of the acidic centers of H-ZKE-AF modified by 3% and 5% ZnO increased. It was found that the highest yield of liquid hydrocarbons was on the zeolite catalysts modified by 3% and 5% ZnS, and is 60.6% and 60.5%, respectively, which is 9% more than in the initial H-ZKE-AF. The activity of the zeolite catalysts modified by zinc oxide and zinc sulfide was in correlation with their acid properties.