Marat I. Amerkhanov's scientific contributions

In this work method to improve the efficiency of the development of shallow deposits of extra-heavy oil using cyclic team stimulation (CSS) technology together with injection of catalyst for in-situ upgrading and solvent was proposed. Oil-soluble catalyst has been developed. Efficiency of catalyst was proved in laboratory. Volume and conditions of catalyst and solvent injection together with steam were determined based on simulation results. Pilot tests of technology were carried out on extra-heavy oilfield in Tatarstan, Russia. The screening of catalysts and solvents together with injection of steam was studied in high pressure reactors under reservoir conditions. Heavy oil displacement coefficients in basic scenario of steam injection and second scenario of steam injection together with catalyst and solvent were measured on self-designed experimental steam injection apparatus. The technology was simulated with tNavigator softwarre (Rock Fluid Dynamics) version 18.2, STARS. Pilot tests were carried out in several stages: preliminary short-term injection of steam to pre-heat the reservoir, injection of catalyst solution and solvent, the subsequent full-scale stage of steam injection, imbibition, and production. The results of field tests confirmed laboratory and simulation data. According to the analyzed samples after six months of field tests, the viscosity at the first stage decreases as a result of dilution with a solvent. The effect of the catalyst, which particles are adsorbed on the reservoir rocks, clearly demonstrated later. It is shown that the combined use of in-situ upgrading catalyst and a solvent in CSS method allows to increase oil recovery factor. At the same time, the produced oil has better properties. Significant degree of conversion of resins and asphaltenes to light fractions was established. Field tests on Ashal'cha oilfield have shown that this technology is effective for the development of shallow deposits of extra-heavy oil.

A significant part of the hydrocarbon reserves in the Republic of Tatarstan belongs to heavy ultra-viscous oil. At the moment, due to the oil price rise, the development of these deposits is an actual task. In the recent decades, development planning has traditionally included the creation of three-dimensional reservoir models. The approaches that are also used are traditional and include data quality control, well log interpretation (determination of stratigraphy and calculation of reservoir properties), construction of a three-dimensional grid and filling it with properties. Meanwhile, the active development of information technology and artificial intelligence makes it possible to automate some of the routine processes. The purpose of this work is to create a chain of software algorithms combined under a digital platform for automating the process of constructing a geological model of ultra-viscous oil (hereinafter, UVO) deposits and calculating reserves on the example of the Republic of Tatarstan. The paper presents the general approaches that made it possible to solve part of the routine tasks of a geologist when constructing UVO deposit models. The tasks to be solved included the automation of stratigraphic boundaries definition, core-log matching, calculation of reservoir properties for wells, as well as determination of OWC position and placement of additional wells taking into account surface constraints. The approaches presented in this work are developed on the example of the UVO deposits of the Republic of Tatarstan, however, the principles used can be transferred to similar objects with the modification of the features used.

Increasing the efficiency of thermal recovery methods is an important and relevant task. This study is devoted to reducing heavy components (resins and asphaltenes) and quality improvement of heavy oil by catalytic hydrothermal treatment. The object of this study is a bituminous sandstone sample from the Ashal’cha reservoir. The catalytic (iron tallate) hydrothermal simulation was carried out under reservoir conditions (200°C, 30 bar). The composition and physicochemical characteristics of the products were studied using elemental and SARA analysis, MALDI, GC-MS, FT-IR. Moreover, the extracted rock is analyzed in XRD and DSA (Drop Shape Analyzer). The introduction of catalyst in combination with a hydrogen donor reduces the content of resins by 22.0%wt. with an increase in the share of saturated hydrocarbons by 27%wt. The destructive hydrogenation leads to a decrease in the sulfur content of upgrading products. This is crucial for the oil reservoirs of the Tatarstan Republic, as their crude oils are characterized by high sulfur content. According to the wettability data, the hydrophilicity of the rock surface increases due to inhibition of the coke formation after the introduction of the catalytic complex. Thus, the oil recovery factor can be increased due to the alteration of the oil-wetting properties of reservoir rocks.

In-situ combustion (ISC) is a promising thermal enhanced oil recovery (EOR) method for heavy oils. However, its field application is still limited due to difficulty in ignition, low combustion efficiency, unstable combustion front, etc. To improve the success rate of ISC process, we investigated the effectiveness of copper-based oil soluble catalyst for catalyzing combustion and in-situ upgrading of heavy oils. High-pressure differential scanning calorimetry (HP-DSC) and TGA were used to investigate the effect of catalyst on the thermochemistry (onset temperature, temperature range of reaction interval, heat effect, etc.) and kinetic parameters of combustion process. A Porous medium thermo-effect cell (PMTEC) was designed to study the catalytic combustion of heavy oil in porous media under air flow. And, a visual combustion tube (VCT) was developed to study the catalytic effect of catalyst on the ISC process, including improving combustion front propagation, in-situ upgrading of heavy oils, and oil recovery. HP-DSC results showed that copper-based oil soluble catalyst significantly shifted the low-temperature oxidation (LTO), transition stage (FD), and high-temperature oxidation (HTO) into lower temperature ranges. Especially for HTO, the end temperature was decreased about 120 °C. It was finished at a narrower temperature region with a higher heat flow, which implies that the combustion efficiency of HTO was greatly improved. TG-DTG data also showed the combustion reaction was transferred into lower temperatures. In addition, from TG-DTG and kinetic data, it can be concluded that the catalyst significantly reduced the activation energy in FD and HTO stage, which thus decreases the reaction barriers between FD and HTO and increases the continuity of reactions between FD and HTO. PEMTC experiments also showed that the ignition temperature of heavy oil combustion in porous media in airflow was decreased about 46 °C by copper-based catalyst. VCT experiments indicated that in the presence of copper-based oil soluble catalyst, combustion front propagate faster, oil recovery was 10% higher than without catalyst, and a deep in-situ oil upgrading was achieved with a significant viscosity reduction (9 times lower) and increase of saturates content (especially alkanes with lower carbon number C11-C17). All these results showed that copper-based oil soluble catalyst has a great potential in improving the efficiency of ISC process and in-situ oil upgrading. Its application can help to improve the success rate and wide application of ISC process for heavy oil recovery, which will promote the highly efficient development of heavy oil resources.

In this study, the hydrothermal upgrading (HTU) of high sulfur-content heavy oil was investigated at sub-critical (Sub-CW), near-critical (NCW) and supercritical water (SCW) conditions. Products obtained after HTU, including gases, liquid, and coke (if formed), were analyzed to understand the upgrading performance at different conditions. At Sub-CW (200, 250, and 300 °C), 250 °C is the optimum temperature where a viscosity reduction from 2073 to 1758 mPa s was achieved with a slight removal of sulfur (mainly sulfur) and the generation of a small amount of light and non-condensable hydrocarbons in gas phase (C1–C4, isoalkanes and alkenes, H2S, CO2 and H2, etc.). At NCW (350 °C) and SCW (400 °C), heavy oil was upgraded into light oil with a significant removal of heteroatoms, an increase of saturates content, a reduction of aromatics, resins and asphaltenes contents, and a high yield of light gaseous hydrocarbons (mainly methane). Simultaneously, each SARA fraction was also greatly ameliorated: the content of light alkanes with low molecular weight in saturates was increased, diaromatics content in aromatics was increased with a reduction of polyaromatics content, aromatics-type carbon atoms in resins was increased with a decrease in aliphatic hydrocarbons. Moreover, MALDI-TOF measurements of asphaltenes show that the molecular weights of asphaltenes were reduced. All these results indicated that HTU at Sub-CW can be used for heavy oil pre-treatment (in-situ or ex-situ upgrading) considering its main effect of viscosity reduction with a small removal of heteroatoms, while HTU at NCW and SWC has a great potential in in-situ and ex-situ upgrading and oil refining as it can convert heavy oil into light oil.

The design of highly efficient catalysts of cracking reactions for intensification of thermal enhanced oil recovery technologies is a relevant task. Moreover, the cost-effective industrial synthesis of such catalysts is very important. In this paper, we discuss the efficiency of bimetallic catalyst, which forms in-situ from the mixture of oil-soluble iron and cobalt precursors, on the processes of upgrading heavy oil in the reservoir of Tatarstan Republic (Russia). A simulation of aquathermolysis was carried out in a high-pressure reactor – autoclave at 150-250оС. The treatment time varied from 6 to 24 hours and the share of catalyst and hydrogen donor was 2 %wt. each. The phase composition of the active form of binary catalyst was estimated from the result of X-ray diffraction measurement. It is characterized by the presence of individual (Fe3O4 and Fe2O3) and mixed oxides with ideal stoichiometry – СоFe2O4. The formation of cobalt sulfide (CoS2) was observed, which indicates the destruction of C-S bonds in high-molecular components of oil. According to the results of SARA-analysis and rheology behavior, the catalyst intensifies destructive processes of resinous compounds (their content reduces more than 45%). This provides an increase in the content of saturated hydrocarbons by 16% and redistribution of aromatic fragments in hydrocarbons with hybrid structure. Thus, the reduction of dynamic viscosity by 32% was succeeded.

The authors consider the technology for monitoring of shallow super-viscous oil (SVO) deposit development process aimed to determine the heated zones distribution corresponding to the drainage areas to enhance the efficiency of development process based on steam injection. The main objective of the work is to develop the monitoring approach based on downhole receivers and interpret the results of surface geophysical survey conducted with the use of downhole receiver tools. The downhole monitoring tools (receivers) are used to improve the sensitivity of the method and to decrease the environmental influence. Each tool includes 3 geophones located in metal case and is connected with the surface by wireline. The tools are set in the bottom hole of evaluation wells and the wells are abandoned. There are several factors influencing the seismic wave velocities (temperature, pressure, saturation etc). To provide more adequate interpretation geophysical methods with different nature are were to use in complex. The surface monitoring methods considered include shallow seismic prospecting and electrical prospecting. The results of periodical geophysical investigation are the maps of seismic wave propagation delay from surface source to the downhole receivers, electrode resistivity maps and interwell resistivity maps for different moments of time. Basing on the change of seismic wave ray velocity the heated regions are identified and the type of fluid saturation estimated with the use of resistivity mapping. The results obtained were used for the development planning including the injection pipe positioning. The interpretation results in terms of heated zones location obtained in the area of study was compared with the direct temperature measurements by periodical optical fiber thermometry conducted in horizontal producer wells. The possibility of steam injection process monitoring by surface geophysics with downhole receiver tools is shown basing on the real field case of shallow super-viscous oil deposit. The relations between geophysical fields considered and reservoir characteristics (temperature, saturation, pressure) are discussed. The work was supported by the Ministry of Science and Higher Education of the Russian Federation (project No. 02.G25.31.0170) and by the subsidy allocated to Kazan Federal University as part of the state program for increasing its competitiveness among the world's leading centers of science and education.