The article discusses the problems and natural and geographical constraints in the design and construction of offshore underwater pipelines in the Russian sector of the Caspian Sea. The Caspian Sea is the largest enclosed body of water on Earth, which can be classified as the largest drainless lake. The area of the Caspian Sea is currently approximately 390.000 km2, located at the junction of Europe and Asia. The length of the sea from north to south is about 1.200 km, from west to east from 195 to 435 km, with an average of 310-320 km. Thus, the main problems in the design and construction of underwater pipelines in the Northern Caspian Sea are: the closeness of the Caspian Sea, which causes limited access to equipment from specialized contractors for pipe laying on the seabed; depths of the waters of the Northern Caspian Sea from 4 to 12 meters create difficulties for design and reduce the number of vessels capable of operating at such depths; seasonality of work due to the ice cover in winter; access to the sea through the Volga-Caspian Canal, which is characterized by high congestion, which limits the rhythm of ship movement and affects timely supplies of materials; the need to coordinate design solutions and construction coordinates with the Russian Ministry of Defense due to the intersection of the work area with the area of exercises of the Caspian flotillas; restrictions of the Federal Agency for Fisheries in connection with the conservation of aquatic biological resources; geological complications associated with soil looseness, the presence of areas with low bearing capacity; the formation of ice hummocks capable of damaging the seabed. These factors influence the timing, cost, and technical solutions for the construction of offshore pipelines, which is important to consider for the successful implementation of projects and negotiations with contractors.
An integral part of the hydrocarbon field development process is the construction of detailed geological models. At the same time, if the deposit has a complex geological structure, it is necessary to construct the most accurate geological model, since a hydrodynamic model is constructed on its basis. With the help of hydrodynamic model, the calculation of the predicted indicators of field development is performed. If the concept laid down in the geological analysis is not confirmed by the development data, an operational review of all available initial data and adjustment of the geological model is required. In this article, a revision of the geological structure of the productive formation B2 of the Bobrikov horizon of the Visean stage of the lower section of the Carboniferous system of dome A of the oil field in the Samara region is carried out due to the identification of a discrepancy between the adopted geological model and the development data during the adaptation of the hydrodynamic model. The geological structure of the work area and tectonic elements confined to the oil and gas structure are presented. In the regional tectonic plan, the studied field is located within the south-eastern edge of the Melekess depression, which is characterized by the submergence of the crystalline basement surface in the western and south-western directions. This structural element is located within the Middle Volga oil and gas region, which is part of the Volga-Ural oil and gas province. Options for improving the geological and hydrodynamic model of the studied formation are proposed in order to study the distribution patterns of collectors, and, consequently, initial oil reserves, based on geological and field data. Improved convergence of the calculated performance indicators with historical ones for a number of wells of the field has been achieved.
The article presents the results of study of polyaromatic hydrocarbons in the Northern Caspian and the Middle Caspian marine environment. The spatial and temporal dynamics of PAHs concentration is described on the basis of the materials gathered during 2017–2021. The study was based on the results of industrial environmental monitoring of the licensed areas of mineral resources use in the northern and middle part of the Caspian Sea. The data of industrial environmental monitoring were analyzed by standard statistical methods. It should be noted that the seasonal variability of PAHs concentrations in the Northern Caspian is characterized by the spring increase in PAHs amount for almost all period under study. A common feature of PAHs dynamics in the northern part of the sea is an upward trend from 2017 to 2020 and its decrease in 2021. No seasonal patterns in the variability of PAHs were found for the Middle Caspian. There are not found stable trends in PAHs concentrations in this region. Concentration range and fraction in the sum of all PAHs were determined for each of the PAH components. As a result of the study the dynamics of water content of marker hydrocarbons, such as pyrene, benz(a)pyrene, fenantren, acetenaften, anthracene, chrysene and naphthalene, was revealed. A redistribution of the mass share of the main components of PAHs occurred in 2019. Acetenaften, fenantren and naphthalene were the most common in the Caspian Sea water. Analysis of molecular-diagnostic ratios proves the presence of anthropogenic and natural sources of polyarenes and the mixed origin of hydrocarbon pollution in the Caspian Sea. Analysis of molecular-diagnostic ratios shows the presence of anthropogenic and natural sources of polyarenes and the mixed origin of hydrocarbon pollution in the Caspian Sea. A number of patterns have been identified through correlation analysis. There is a strong feedback between the ratios (pyrene + benz(a)pyrene)/(fenantren + chrysene) and fenantren/anthracene in the Northern Caspian. And there is also a direct correlation between the ratios naphthalene/fenantren and anthracene/(anthracene + fenantren). Analysis of correlation relationships of indicator ratios in the Middle Caspian did not reveal any dependencies, which may indicate a variety of sources of contamination by polyaromatic hydrocarbons.
This study examined teachers’ capacity to implement the Competence-Based Curriculum (CBC) in public secondary schools within Bagamoyo District, Tanzania, with a specific focus on assessing teachers’ knowledge and skills in CBC implementation. The research was guided by Vygotsky’s Constructivist Theory, which emphasizes learner-centered and interactive approaches to knowledge construction. A mixed-methods approach was employed, integrating quantitative and qualitative techniques within a descriptive survey design. The study involved 116 respondents, including Ward Education Officers, heads of schools, teachers, and students. Data were collected through questionnaires, semi-structured interviews, classroom observations, and documentary reviews. Quantitative data were analyzed using descriptive statistics with the aid of SPSS, while qualitative data underwent thematic analysis. Findings revealed that teachers’ capacity to implement CBC remains limited due to insufficient professional training, low confidence in lesson planning and assessment, and minimal practical exposure to learner-centered methods. Although some teachers applied interactive strategies such as group work, the majority relied on traditional, teacher-centered approaches. The study concludes that effective CBC implementation requires strengthening teacher capacity through comprehensive professional training, ensuring adequate teaching and learning resources, and promoting supportive institutional practices. It recommends targeted in-service training, enhanced provision of resources, stronger monitoring mechanisms, and increased financial investment in secondary education. Future research should explore comparative analyses across regions, the longitudinal effects of professional development, and the role of school leadership in advancing CBC implementation.
Несмотря на совершенствование геолого-технических средств и методов геологоразведки, годовые открытые запасы нефти и газа в Пермском крае уменьшаются. Текущая мировая геополитическая обстановка диктует свои правила. Минимизировать экономические риски для нефтегазодобывающих компаний можно с помощью сосредоточения внимания на внутренних портфелях активов - освоении мелких и очень мелких месторождений, особое внимание стоит уделять поиску пропущенных залежей на действующих активах, расширению и поддержанию их сырьевой базы [Роуз, 2011]. Последнее возможно за счет применения современных методов геофизических исследований скважин, которые позволяют снизить неоднозначность геолого-геофизической интерпретации за счет регистрации большего количества физических параметров, с большей достоверностью оценивать ключевые петрофизические параметры, оптимально планировать разработку и осуществлять ее контроль [Горбачева и др., 2017, 2018, 2025]. Особое внимание на территории при поиске пропущенных залежей следует уделять анализу рисков - идентификаций рисковых событий и их оценке, разработке мероприятий по реагированию на риски и их снижению. Despite the improvement of the geo-technical means and methods of geological exploration, annual discovered oil and gas reserves in Perm Region are decreasing. The current global geopolitical situation dictates its own terms. Economic risks of oil and gas producing companies can be minimized by focusing on the internal asset portfolios - development of small and very small oilfields. Special attention should be paid to the search of missed deposits at existing assets, expansion and maintenance of their raw material base [Rose, 2011]. The latter is possible with the help of the modern well-logging operations, which allow to reduce geological and geophysical interpretation uncertainty by recording a lerger number of physical parameters and to estimate key petrophysical parameters with lerger reliability so that optimally plan reservoir engineering and fallow-up [Gorbacheva et al., 2017, 2018, 2025]. Special attention in the territory when searching for missed deposits should be paid to risk analysis - identification of risk events and their assessment, development of measures to respond to risks and their reduction.
