Vol 335, No 6 (2024)

Relevance. The main technological process when constructing oil and gas wells is effective wellbore cleaning, especially when drilling horizontal and deviated wells. The article deals with the peculiarities of wellbore drilling technology according to the traditional method in combination with water and hydrocarbon-based polymer-clay solutions, as well as improvement of drilling mud removal properties taking into account density, drilling pump productivity, rheological parameters of the fluid, geometry of the well annulus, shape and concentration of drill cuttings particles. Insufficient cleaning of the well bottom hole causes undesirable phenomena leading to various complications. The object of the research is the technology of cuttings transportation along the wellbore to the surface. The basic formulas characterizing the work of interchangeable hydromonitor nozzles are given. The quality of wellbore cleaning depends on the degree of flow turbulence.

Aim. To develop technical solutions that contribute to improving the quality of wellbore cleaning.

Methods. Optimal geometrical parameters of hydraulic nozzles for double-deck anti-vibration bit and design of drill pipes with helical ribs have been established by experimental works.

Results and conclusions. A double-deck anti-vibration bit with interchangeable hydro-monitor nozzles and drill pipes with helical ribs were developed. Implementation of these developments in the practice of drilling operations will improve the quality of wellbore cleaning by creating a turbulent regime of drilling fluid flow.

Relevance. Pipeline transportation of oil and oil products is one of the most efficient and cost-effective modes of transport in the modern world. Despite this, this type of transport can also be environmentally hazardous in case of leakages caused, for example, by corrosion, violation of operating rules, unauthorized tie-ins. Non-operational localization and liquidation of leakages and unauthorized tie-ins is often not only the cause of significant financial losses, but also accidents and pollution of the area of varying severity and scale. Nowadays, the issue of determining the leakage that has occurred and its location in the shortest possible time remains open. In this regard, the development of new and improvement of existing methods for detecting leakages and tie-ins in pipelines is an urgent task today.

Aim. To study the effect of the total head shift, which occurs when taking into account the change in the power of pumping units due to product leakage, on the accuracy of determining the localization of leakage or unauthorized tie-in; to improve the existing methods for determining the leakage coordinate taking into account the change in the total head developed by the oil pumping station.

Methods. Modeling the occurrence of a leakage or unauthorized tie-in with a different percentage of product losses, constructing hydraulic slope lines with leakages of varying intensity in different coordinates, a comparative analysis of the results obtained from the considered existing methods and those proposed by the authors.

Results. The authors have modeled the leakages in various coordinates and determined the possibility of the proposed method operation for finding the coordinates of leakages. They calculated as well the errors in determining the location of the tie-in or leakage, depending on the pump power drops when the product flows out of the oil pipeline. The paper introduces the formula for the localization of leakages or tie-ins, considering the change in the power of pumping units and, as a result, the total head.

Relevance. Currently, the rational and economical use of petroleum products is of particular importance. This applies, among other things, to all known types of oils. Waste oils entering the natural environment are only partially neutralized as a result of natural processes. Most of them are a source of pollution of soils, water bodies and atmospheric air, leading to disruption of the reproduction of birds, fish, mammals, and having a harmful effect on humans. Thus, the widespread problem of collecting and recycling waste petroleum products is a relevant, cost-effective and knowledge-intensive area; since with the correct organization of regeneration, the cost of recovered oils is 40–70% lower than the cost of fresh oils with almost the same quality.

Aim. To improve the technology of recycling spent petroleum products in the conditions of the northern territories in order to achieve eco- and energy efficiency. After the regeneration stage, used oils can be used for their intended purpose – returned to equipment lubrication systems, this is up to 70–80% of the original amount of waste oil generated. The remaining, “unrecovered” amount of 20–30% is burned in the form of a water-fuel mixture at enterprises equipped with liquid fuel boilers. The information available in the literature is insufficient to create an effective system for the disposal of used oils and other petroleum products, especially in the circumpolar territories. A differentiated approach to the problem is required, taking into account the peculiarities of the climate, the remoteness of the Arctic territories from the transport infrastructure, with mandatory compliance with environmental standards.

Methods. Cavitation technology (i. e. cavitation effects) and the LSTM (Long Short-Term Memory) deep learning method for processing hydrocarbon waste using the example of industrial oil W30 and, accordingly, modeling the migration of pollutants from industrial objects in open natural water sources.

Results and conclusions. The results obtained indicate that the integrated use of raw materials is the result of the most complete, economically and environmentally justified application of all advantageous components contained in raw materials, as well as in production waste. Any hydrocarbon waste can be considered as secondary material resources that can be used for economic purposes, partially or completely replacing traditional types of material, raw materials and fuel and energy resources, the main value of which is their constant reproducibility in the production sector.

Relevance. Lumber drying is associated with high risks of obtaining a low-quality or even unusable product. The problem under consideration has a number of reasons, both in violation of the technological process and in incorrect settings of drying mode parameters at different stages. The procedure for automated adjustment of parameters is usually associated with a linguistic assessment of the quality of the product, according to which a decision on adjusting the parameters should be made, taking into account signs of a violation of the technological process. Technical and scientific publications contain generalized information about methods for selecting parameters for various situations, which can be formalized and included in algorithms for adjusting the parameters of a programmable logic controller.

Aim. To create an algorithm using a Fuzzy controller that allows you to configure process parameters and adapt the drying chamber to the optimal parameters for drying lumber under given operating conditions.

Methods. Analysis of the technical process database obtained during one and a half years of operation of the main parameters dispatch system for 28 full lumber drying cycles, with the aim of forming an automated adjustment algorithm that takes into account the lumber drying conditions.

Results. The authors have created an algorithm for automated adjustment of parameters for three stages of drying based on linguistic ideas about the quality of the product. The algorithm eliminates the possibility of obtaining a low-quality product, as well as encourages service personnel to correctly generate a technological process passport.

Conclusions. The inclusion of an automated parameter adjustment loop in the control circuit allows us to minimize the number of poor-quality processes when starting to operate a new drying chamber and eliminate defects in further technical processes.

Relevance. The need to study the elemental composition of the organism of wild and domestic animals in natural environments with different levels of chemical elements.

Aim. To reveal features of the elemental composition of the organism of the Altai red deer (Cervus elaphus sibiricus Severtzov, 1873), wild boar (Sus scrofa scrofa Linnaeus, 1758) and domestic pig (Sus scrofa domesticus Erxleben, 1777) in Ongudai district, Altai Republic, including the area with signs of active geophagy.

Objects. Organs and tissues of wild and domestic animals.

Methods. Mass spectrometry with inductively coupled plasma; atomic-emission spectrometry; ion chromatography, analytical electron microscope with energy dispersion spectrometer.

Results. The median values of chemical elements concentrations in the organisms of the Altai red deer, the wild boar and the domestic pig have been determined. S, Cl and K showed the highest values in the composition of macroelements and La, Ce, Nd and Th among rare-earth and radioactive elements. Among the elemental composition features of the studied animals, an increased accumulation of Hg and Pb in the Altai red deer; metals of the Fe-group, W, as well as rare-earth and radioactive elements – in the boar; platinoids – in the domestic pig. In comparison with the results of previous studies, increased concentrations of Hg in red deer kidneys, W in boar bronchi and Pb in the brain of domestic pigs were recorded. Assumptions were made about the factors influencing the formation of the elemental composition of the body of animals. For red deer and wild boar these are the factors of nutrition (including geophagy) and features of accumulation of elements in bone tissue; for domestic pigs – features of forage and local metallogeny, including composition of natural waters.

Relevance. The necessity to study arsenic behaviour in soils as one of the main pollutants of depositing environments in areas of mining and metallurgical industry. In recent decades, arsenic emissions into the environment have reached a huge scale, so this element attracts the attention of researchers around the world. But in spite of all the studies of this problem, there are still some aspects that need to be clarified to understand the geochemistry of arsenic. This paper deals with spolic technosols with critically high arsenic content in the soil profile with alternating water-logged and dry conditions. As one of the main soil-forming elements, orthosteins contain significant amounts of iron and manganese compounds and are capable of adsorption and involvement of the elements in nodule formation.

Aim. To determine the influence of orthosteins on arsenic accumulation in soil subjected to intensive anthropogenic load.

Object. Ortsteins spolic technosols in the zone of operation of copper smelting plant and background soils not exposed to pollution.

Methods. Arsenic was determined by inversion voltammetry method. Morphological characterisation and patterning of the orthosteins were performed by scanning electron microscopy using a Thermo Fisher Phenom XL G2 Desktop SEM unit.

Results. The study of morphological features of orthosteins revealed differences in soils subjected to greater anthropogenic load. Arsenic was not detected inside the orthosteins in all studied soils. Also arsenic concentrations in the total mass of ortstein is up to 40–50% of the soil mass. This fact indicates the accumulation of arsenic by surface adsorption and the appearance of orthosteins as a geochemical barrier. The data obtained in the course of this work can contribute to the search for ways to clean up soils contaminated with arsenic, as well as provide an understanding of the basic processes of the behaviour of this element in soil formation.

Relevance. Relationship with the Takata formation of diamond reservoir rocks and previously discovered deposits and the presence of prospects for discovering new ones in the zone of the forward folds of the Urals.

Aim. To reconstruct the conditions of sedimentation and composition of rocks, the source of the removal of terrigenous rocks of the Takata formation based on the results of studying the "Yuzhnaya Rassolnaya" section.

Objects. Terrigenous rocks of the Takata formation in the "Yuzhnaya Rassolnaya" section located in the western part of the alluvial diamond deposit "Yuzhnaya Rassolnaya" in the Krasnovishersky district of the Perm Territory.

Methods. Lithofacies analysis, petrographic study of thin sections in transmitted light using crossed nicol methods, determination of the content of rock-forming oxides by X-ray fluorescence on an S8 Tiger (Bruker) spectrometer, analysis of rock-forming elements on glassy disks. Impurity and microimpurity elements (with a content of <5%) were determined using a certified method for defining elements by inductively coupled plasma mass spectrometry according to the method STO TGU 048-2012. The analysis was performed by ICP-MS on an Agilent 7500cx quadrupole mass spectrometer (Agilent Technologies Inc., USA) using an internal (In Internal standard, Inorganic Ventures, USA) and an external standard SGD-2A (GSO 8670-2005).

Results. Lithological-facial, mineralogical, petrographic, lithogeochemical studies of Takata terrigenous deposits were carried out in the "Yuzhnaya Rassolnaya" section in the area of the Polyudovo-Kolchimasky anticlinorium of the Western Ural folding zone, which made it possible to clarify the sources of matter and sedimentation conditions. The formation of sediments occurred in a transitional sedimentation environment. A transgressive sequence is observed from bottom to top. Terrigenous rocks of the Takata formation include rocks of the first and second sedimentation cycles. They were cut off due to the destruction of primary igneous (acidic and basic compositions) and metamorphic rocks, as well as sedimentary rocks. The totality of the material characteristics of the terrigenous rocks of the Takata formation, taking into account the published data, allowed us to assume that sedimentation of the rocks occurred on the passive continental margin, with the supply of clastic material due to the erosion of internal raised blocks of the foundation of the East European Platform. The activation of the latter occurred in the Emsian time with the manifestation of general lithospheric folding. At the same time, water flows carrying weathering products from the East European Platform eroded sedimentary rocks of the Riphean, Vendian, Ordovician and Silurian, which fragments we observe in small quantities when describing thin sections.

Relevance. Recently, ESG (Environment, Social, Governance) principles have been given an important role in the agenda of oil and gas companies – this is an actively developing global trend in the modern business environment. One of its key aspects is a responsible attitude to the environment, increasing the priority of solving environmental problems arising from the extraction of hydrocarbons. A significant environmental problem is, in particular, pollution of freshwater horizons during oil production due to their poor-quality insulation when well cementing. At the same time, in the space of the well behind the casing, there is a flow of borehole fluid to freshwater horizons, which has a negative impact on the environmental situation in this region. In this regard, monitoring the technical condition of wells crossing freshwater horizons is an important and urgent task.

Object. An operational well drilled through freshwater horizon, in which geophysical studies are carried out by the method of active thermometry – local heating of the casing section is carried out and the dynamics of the temperature field in it is studied.

Aim. To identify qualitative patterns and obtain quantitative estimates of the effect of the fluid flow in the space behind the casing (column space) on the temperature field in the casing.

Methods. Numerical mathematical modeling of thermal and hydrodynamic processes in a well using the software package Ansys Fluent (ANSYS Academic Research CFD license, agreement with Bashkir State University dated 06/15/2020).

Results. The authors have studied the effect of a plane-parallel horizontal fluid flow of the freshwater horizon on the azimuthal temperature distribution of the casing string during induction heating. It is shown that in the case of leakiness of the cement ring in the interval of the freshwater horizon, an inhomogeneity of the azimuthal temperature distribution of the column is observed, reaching a value of few more K. The authors carried out the simulation of induction heating in the well with liquid column flow to the interval of the freshwater horizon. It is shown that the sign indicating the overflow is the occurrence of a temperature disturbance area vertically above the induction heating interval with a length of more than 1 m. In general, the results of the performed studies show the informativeness of the active thermometry method in relation to the diagnosis of the technical condition of wells drilled through freshwater horizons.

Relevance. The necessity to investigate the mechanism of gas (methane) flow occurring during decomposition of gas hydrate formations within the layers of bottom sediments. This process is evident through substantial releases of methane bubbles in extensive shallow regions of the Russian Arctic shelf and has the potential to alter the equilibrium of atmospheric methane, a critical greenhouse gas.

Aim. To quantitatively investigate, within the context of gas transport in bottom sediments, the impact of free and bound gas within the pores on the nonlinearity of filtration flows.

Methods. The model samples with filtration properties similar to those of the bottom rocks of the East Siberian Arctic shelf. During the experiments, a specific amount of gas was injected into the saturated model sample, followed by the measurement of its effective permeability during a slow decrease in pore pressure gradient. The obtained curve was interpreted within the framework of the threshold gradient model.

Results. The experiments yielded curves showing the dependency of the threshold gradient magnitude on gas saturation for several samples. It was found that the threshold gradient linearly increases with the growth in gas fraction within the pore space. Already at a gas fraction of approximately 0.02, this value in the experiments reached 0.01 MPa/m, corresponding to the hydrostatic pressure gradient in water. This suggests that even areas with relatively low gas saturation may be impermeable to convective fluid flow. This possibility should be considered when creating models for bubble gas transporting through the rock layers of bottom sediments. Furthermore, the existence of gas-saturated zones with threshold gradients can significantly impact the vertical profile of pore pressure and lead to a reassessment of the depth of gas hydrate stability zones.

Relevance. As readily available oil reserves are developed and production technologies development, oil and gas companies are gradually moving to exploration of previously unprofitable assets. Over the past five years, several oil-and-gas condensate fields with oil rims have been put into operation in Western Siberia. Their development is further complicated by oil high viscosity and poor cementation of the reservoir rocks. Low values of critical drawdown do not allow oil to be produced without destruction of the productive formation, and mechanical impurities entering the well lead to spillage of perforation intervals and downhole equipment failures. The use of mathematical modeling in relation to the operation of wells in the conditions of the removal of mechanical impurities will make it possible to control production and select the optimal well operation mode.

Aim. Forecasting the trouble-free operation of a production well under conditions of high removal of mechanical impurities.

Objects. Producing oil wells; the subject of the study is the movement of solid particles in the wellbore of a production well, the relationship and dependence of formation of sand plugs on the operating parameters of the well.

Methods. Theoretical research methods – analysis (analysis of models for calculating the critical flow velocity in a horizontal pipe (calculation of the critical velocity in a single-phase flow; calculation of the critical velocity in a multi-phase flow; calculation of the critical velocity based on the balance of forces)) and modeling (simulation of work wells with the removal of mechanical impurities). The totality and combination of these methods are adequate to the goals and objectives, the object and subject of the study of this work.

Results. The problem of sand production is typical not only for fields that are in the late stages of development, but also for fields that have recently been put into operation. Sand shows up are a complicating factor in the operation of wells at the Severo-Komsomolskoe high-viscosity oil field located in Western Siberia. The main object of development of the studied field is a weakly cemented sandy layer. Oil production in such difficult areas requires a very careful approach to the choice of development system, to the selection of methods to deal with complications, including the choice of the right method to limit sanding. However, regardless of the approach taken to solve the problem of sand production, some rock will still flow into the well. To prevent the formation of sand plugs, it is necessary to understand the nature of the movement of solid particles along the wellbore. It is possible to assess whether a well is capable of carrying out solid particles from a horizontal section using modeling in specialized software products. Modeling of the well operation, taking into account the influence of mechanical impurities, made it possible to solve the following problems: 1) determine the fluid to carry rock particles out of the horizontal section; 2) identify the areas in which there is a risk of sand plugs; 3) present the dependence for calculating the critical speed for high-viscosity oil with different water cut; 4) assess how the water cut and gas factor affect well operation in conditions of high removal of mechanical impurities; 5) calculate the time of formation of sand plugs.