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Study of reservoir rocks geomechanical properties for the hydraulic fracturing design

Ernest R. Agishev, Gennady S. Dubinsky, Vyacheslav Sh. Mukhametshin, Zukhra N. Sagitova

Introduction. The oil and gas resources of Russia have been growing mainly with hard-to-recover reserves of old producing regions and deposits located in hard-to-reach regions with undeveloped infrastructure for the last quarter of a century. The difficult conditions for the development of such fields and the extraction of residual reserves of the “old” fields create problems in hydrocarbons production, the complex geological structure causes great difficulty.Since the geological structure peculiarities of the fields often increase the risks of rapid well production flooding, the urgent task is to reduce such risks during hydraulic fracturing, to maintain the cost at a profitable level, and to ensure environmentally friendly conditions. The article considers the possibility of reducing the risk of water inflow along a hydraulic fracture and increasing the correctness of the fracture development prediction in a water-prone direction, which should ensure sufficient technological efficiency of work. Purpose of research is the need to develop innovative techniques and updated approaches to hard-to-recover oil reserves development, new techniques to improve the quality and success of work while maintaining their profitability. Research methodology. A comprehensive analysis of the hydraulic fracturing actual results, the results of laboratory studies and subsequent field tests. Research results and discussion. Based on the conducted studies, a technique has been proposed that allows determining the hydraulic fracturing design which makes it possible to reduce the risks of arbitrary, uncontrolled fracture propagation. The conducted field tests confirmed the significance and reliability of the proposed methodology. Findings. The article presents the results of studies of the hydraulic fracturing process. An updated technique for predicting hydraulic fractures is proposed, considering the reservoir rocks geo-mechanics. Field tests were carried out, which showed the effectiveness of calculations using the new technique – fluid inflows with reduced water cut and increased oil production from the target reservoir were obtained, i.e. penetration of cracks into the aquifer is not allowed. It has been established that during hydraulic fracturing it is necessary to fix the fracture with no more than 5 tons of prop pant. It was determined that the pad volume should be reduced to 50% of the injected prop pant weight. It was found out that it is preferable to use a linear gel to reduce the height of the hydraulic fracture, as well as to assess the need to correct the model based on the test operations results. The results of the research can be used on deposits similar in geological and commercial characteristics to those studied.

Number of views: 332

Determination of the optimal strength and speed of soil digging of a single-bucket hydraulic excavator with a spherical shape bucket

Grigory G. Buryi, Ilya K. Poteryaev

Introduction. The paper describes the scope and purpose of single-bucket hydraulic excavators. The method of digging a single-bucket excavator with a bucket of spherical shape, which allows to increase productivity, is considered. The urgency of increasing the productivity of these machines is formulated. The purpose of the work: to determine the optimal strength and speed of digging the soil of a single-bucket hydraulic excavator with a spherical bucket. Research methodology. To confirm the effectiveness of the proposed bucket design, a diagram of the forces acting on it during digging is presented. The rheological model of the process of digging with a bucket of spherical shape is considered. A mathematical model in the form of a system of second-order differential equations has been compiled on the basis of the force scheme and the rheological model.
Research results. A mathematical model has been identified that makes it possible to calculate the dependence of the speed and optimal force when digging the soil with a spherical bucket of a single-bucket hydraulic excavator, depending on the design parameters of the bucket and the parameters of the soil. The dependence for determining the friction force of the soil inside the bucket arising during digging is given. The dependencies for determining the weight of the soil in the bucket and the bucket itself are described. The dependence for calculating the lateral pressure of the soil using a stabilometer is given. The dependences of the calculation of the friction force of the external soil on the bucket and the friction force of the external soil on the soil in front of the bucket edge are presented. A dependence for determining the normal force from the external soil to the compacted soil in front of the bucket edge is proposed. The concept of a "compacted core of the soil" in front of the bucket edge is given and the dependence for determining its depth is given, however, a more precise definition of the latter requires additional research. A dependence is proposed for determining the mass of soil located in front of the bucket edge. The conditions for the possibility of digging the soil are accepted, in which the digging speed is greater than zero, and the digging force is minimal. An algorithm is described that allows you to select the minimum force for the digging process based on the dependencies given in the work. A block diagram of the algorithm for selecting the minimum force for the process of digging with a spherical bucket is given. The selection of the minimum digging force will confirm the effectiveness of a single-bucket hydraulic excavator with a spherical bucket.

Number of views: 297

Instrumental measure of seismic intensity based on K-Net data

Vladislav B. Zaalishvili, Dmitry A. Melkov, Madina I. Fidarova, Konstantin S. Kharebov

Relevance. Traditionally, seismic impacts in the practice of seismic construction are estimated by the magnitude of the peak horizontal ground acceleration. This approach, being simple and convenient for practical use, is reflected in building codes for seismic design and construction in seismically hazardous areas in most countries of the world. At the same time, studies of instrumental records show that often the value of the dynamic gain does not depend on the values of peak accelerations. In recent years, attempts have been made in the calculations of buildings and structures for seismic effects to use the values of ground vibration velocities, which, according to engineers, allow you to directly take into account the kinetic, acting and absorbed energy of the object under study. When analyzing the consequences of strong and destructive earthquakes, it is necessary to take into account the multifactorial influence of the earthquake process on buildings. In this regard, it becomes unclear what determines the seismic resistance of a structure or which impact parameter determines its seismic effect and is the most important for an adequate assessment of seismic resistance. The aim of the work is to establish the relationship between macroseismic intensity and instrumental indicators of seismic event records. Research method. The analysis was carried out according to the K-net network with a selection of records obtained in areas with different soil conditions (parameter Vs). The recording parameters, in this case, were calculated according to the methods proposed by various authors: Arias intensity, cumulative absolute velocity, Ang intensity, Hausner intensity, Fajfar measure, total energy measure, real and normalized spectrum areas, as well as weighted average frequency, predominant period and duration. The connection of each of the parameters was estimated by the method of Pearson’s correlation, Fisher’s criterion and mutual information. Research results. As a result, the parameters for a number of criteria that best describe the seismic intensity were identified. The article presents the most suitable parameters for «macroseismic intensity» instrumental measure. The highest correlation of which with the intensity, based on the use of generally accepted methodology, was: the Anga intensity (0.76), the area of the so-called. real spectrum Sr (0.73), cumulative absolute velocity CAV (0.73), Arias intensity (0.7), rms acceleration (0.68), peak horizontal displacement PHD (0.51). It should be noted that the correlation for the Hausner intensity unexpectedly amounted to only 0.38. When using machine learning (Lasso), the parameters are narrowed down. The most informative features are the peak horizontal velocity (PHV), the cumulative square of accelerations - the Arias intensity, the maximum value of the Fourier amplitude spectrum, the Anga intensity and the Fajfar measure. At the same time, the correlation for the area of the real oscillation spectrum is also quite significant.

Number of views: 341

Territorial features of demographic development of mountain settlements of the Republic of North Ossetia-Alania

Vitaly S. Belozerov, Ivan A. Soloviev, Natalia A. Shchitova, Larisa K. Dzakhova

Purpose of the study. Identify the spatio-temporal transformations of the demographic development of mountain settlements in the Republic of North Ossetia-Alania over the past decade. Research methods: during the research, traditional geographical methods were used - comparative geographical, statistical, descriptive and analytical, field field observations. Results and discussion. Mountain settlements of the Republic of North Ossetia-Alania are located in the Vladikavkaz urban district, as well as in the Prigorodny, Alagirsky and Irafsky districts. They are mainly concentrated in low-mountain and mid-mountain zones. At the same time, the dominant part of the population lives in low mountains, which testifies to the predominance of the small-settlement structure of settlement in the middle and high mountains as compared to the low mountains. By the nature of the position in the relief, mountain settlements are divided into two types - located on slopes and high plateaus and in intermontane basins and valleys. The latter have undeniable advantages associated with more favorable natural conditions, the development of transport and social infrastructure, which contributes to the preservation of the population and curbing depopulation processes. In general, the mountainous areas of the Republic are experiencing a steady demographic decline, which is manifested in a decrease in the population and a decrease in its share in all mountain municipalities. At the same time, in a number of settlements, natural growth remains weakly positive. The increase in depopulation is mainly associated with the migration outflow of the population, which is most pronounced in the high-mountainous, with an unfavorable geographical position of the settlements. In the Prigorodny District, the migration loss is mainly due to the village of Tarskoye (which may be a kind of reminiscence of the well-known negative events). At the same time, in a number of administrations, tendencies of a decrease in the migration loss or even a slight migration growth have been revealed. Thus, an almost zero balance of migration is characteristic of the settlements of the Dargav administration, and in the settlements of the Karamadon, Koban, Fiagdon administrations, a migration increase was found. An unexpected increase (albeit very weak) is demonstrated by the settlements of the Galiat, Gular, Zadale, Makhskoy rural administrations. Conclusions: The study revealed significant intraregional, intraregional and intersettlement spatio-temporal imbalances in demographic development associated with natural and socio-economic circumstances. It has been established that sustainable development of the mountainous territories of the Republic of North Ossetia-Alania is possible provided that human potential is preserved, since allows reproducing the original culture of the Ossetians and preserving the mountainous traditional architecture. The most favorable situation is developing in settlements that are involved in agglomeration processes and located in the suburban area close to Vladikavkaz (with the exception of the village of Tarskoye), as well as villages with an advantageous transport and geographical position and located on the main highways. It seems promising to involve the local population in tourist activities and the development of various types of tourism in mountain settlements.

Number of views: 456

Electrochemical leaching of polymetallic ore under the action of asymmetric current pulses and the addition of a surfactant

Yuri I. Kondratiev, Oksana A. Sokolova, Dzambolat A. Kambolov, Andrey S. Miroshnikov

The article presents the results of studies on the electrochemical leaching of metals from poly-metallic ores using sulfuric acid-chloride solutions under the action of a reversible infra-low-frequency direct current with varying density and the addition of a surfactant. Mathematical models of leaching indicators have been developed depending on the density, duration of the forward and reverse polarity of the current. It is revealed that the most optimal mode is the ore leaching under the action of a reversible direct current with varying density and duration of the reverse current. It is determined that the reverse current density is 6 times greater than the forward current density, and the duration of the reverse current pulse is 0.2 of the duration of the forward current. At the same time, Kazakhstan, like other countries with the transit economy, will have to overcome the risks and challenges that have emerged as a result of global digitalization. The article shows that to stimulate digitalization of geological exploration, significant investments are needed, which will require, alongside with government regulation, searching for new forms and mechanisms of public-private partnership.

Number of views: 400

Models of sustainable socio-economic development of the mountain regions of Southern Siberia

Bella A. Krasnoyarova, Tatyana N. Biche-ool, Svetlana P. Surazakova

The aim of the study was to analyze the models of sustainable development mountain regions of Southern Siberia by the example of Altai and Tyva Republics. Materials and research methods. The study was based on the methodology of system analysis and strategic planning. Strategic documents of socio-economic development of Altai and Tyva Republics were used. Discussion. Peculiar features of the Altai Republic development are characterized by a weak diversified economy, a low living standard of the population, a poorly developed social and engineering infrastructure, bad transport development and connection with other territories, including unstable energy supply. The analysis of its Development Strategy suggests that the ecological tourism development may be take a leading position here in the near future. The Republic of Tuva is distinguished by other strategic development guidelines. Since post-reform years, the development of the republic is associated with the construction of the Kyzyl-Kuragino railway and industrialization, i.e. the development of rich mineral deposits. Currently, the transport system of Tyva is represented by automobile, air and domestic seasonal water traffic, which needs development and reconstruction, there are also problems with the energy supply of the region. Conclusion. Mountainous relief, unique natural conditions of the Altai and Tyva republics are key conditions in the development of these regions. The Altai Republic has chosen an environmentally oriented model with the preservation of nature and the development of ecological tourism. The Republic of Tuva continues the traditional industrial path - the development of mineral deposits. From the point of view of the authors, the traditional industrial path of development is unacceptable for mountainous areas and may lead to the depletion of natural resources, environmental degradation and the loss of national and ethnic identity of the population.

Number of views: 487

On the features of the spatio-temporal variability оf the heat waves characteristics of the last three decades (Ararat valley, Armenia)

Varduhi G. Margaryan, Ilyas G. Ikramov, Kuralai T. Abdraimova, Elmira K. Ibragimova

The aim of this work to study, identify the repeatability and duration of heat waves of the study area. For it were suggested and decided the following tasks: Findings. The study of regularities of variability of the spatial-temporal distribution of characteristics of heat wave in conditions of regional and global changes of climate is current task of modern geographical science. Extremely high temperatures and heat waves of study area excessively conditioned by the influence of secondary thermal depressions from the Arabian Peninsula, a number of cases that last for 2-3 decades are significantly increased. Tropical thermal depression, forming of extreme hot summers and heat waves, have cycles of activation and weakening, periodicity of which is estimated at 20-22 years. Starting from July (sometimes from the second half of June) to the last ten days of August (sometimes to first half of September), weather conditions of Ararat valley are formed under influence of thermal depression. The invasion of southern and south-eastern tropical warm and dry air currents from the Arabian deserts is increasing. As a result in some years the air temperature in Ararat valley is increased to 40-43 °C, and relative humidity is low than 30%. Heat waves are dangerous weather phenomena, is threat for live and activity, are characterized with some negative consequences. They can be accompanied by droughts and dry winds, forest fires, desertification, disruption of the natural ecosystem, economic damage, decreased working capacity, psychological and sociological consequences, even deaths. Temporal tendencies in course of values of the characteristics of heat wave for last 2-3 decades have positive unambiguous character, more frequent heat waves and extremely warm summers. Heat waves of low and medium intensity have a particularly high frequency. The probability of strong waves is less. The study area is distinguished a characteristic regime and an almost uniform spatial distribution of summer extreme high temperatures. They range from 41,5 to 42,6 °C. The entire study area is vulnerable to heat waves. Heat waves can cause dangerous meteorological phenomena such as droughts or dry winds, which cause great damage to various sectors of the economy, especially agriculture. Therefore the results of the work can be used in the field of agriculture, mitigating and reducing the consequences of possible damage caused. They can also be used in agrometeorological forecasts. In the study area, summer conditions become warmer and drier, which should be taken into account when developing strategic programs for the future development of this area.

Number of views: 435

A study on the entrepreneurial orientation of the 65-villagers in a part of slope of mountain Arjuno East Java Indonesia

Yustinus Budi Hermanto, Lasman Parulian Purba, Matheus Nugroho

Our interest is to explore such a characteristic of the villagers who live in a part of the slope of Mountain Arjuno, located in the East Java Province of Indonesia, before their existing entrepreneurial orientation. Using question-naires -developed based on (Miller, 1983) definition about entrepreneurial orientation-, spread to the villagers there and their analysis, it was found that their entrepreneurial orientation E.O. following equation as - 0.003 + 0.334 innovativeness I + 0.334 proactiveness P + 0.333 risk-taking R.

Number of views: 499

Residents’ perception of pilgrimage tourism sustainability In mountain regions: The St. James Primitive Way Case in Asturias

Marta Magadán-Díaz, Jesús Rivas-García

The main objective of this research is to evaluate the changes in local conditions in the economic, sociocultural, and environmental perspectives in association with the development of the pilgrimage tourism sector from the perspective of the residents of mountain areas through which the St. James Primitive Way passes in Asturias. The specific objective is to evaluate the sociodemographic factors of such perceived changes using Logit regression analysis and seemingly unrelated regression analysis. The results obtained indicate the following: firstly, that, although the residents positively value the non-overcrowding of pilgrims on this primitive jacobean route, their perceptions detect some negative changes in the surroundings of Pola de Allande and Grandas de Salime related to noise pollution, the management, and treatment of waste and the state of the Jacobean route; secondly, residents perceive the conservation and condition of the St. Jacques’ route as poor and that there are no improvements in infrastructure and public transport services; Finally, thirdly, the impacts of the Primitive Way, today, although positive, are very modest and are mainly limited to two sectors: hospitality and accommodation, which are the activities where employment is being generated. Residents surveyed perceive positive changes in employment and income distribution and negative changes in the evolution of the prices of goods and services and the cost of living.

Number of views: 411

Promising direction of Sadon ‘s potential recovery (RNO-Alania)

Vladimir I. Golik

The restoration of the former potential of the deposits of the Sadonsky ore node depends on the success of extracting metals from poor ores and leaching waste with environmental improvement. The modernization of technology for the development of existing reserves of deposits is carried out on the basis of the results of the performed research. Report. The relevance of the work is explained by the need to restore the industrial potential of a large location lost during the crisis. The purpose of the work. Substantiation of the possibility of resuscitation of the lost potential of mining enterprises based on the use of substandard raw materials for the production of metals and commercial products. Research methods: systematization, generalization and analysis of theoretical and experimental studies performed at the fields under consideration. Results. The concept of environmental protection and resource-saving technology for the development of deposits of the Sadonsky ore belt has been formed. The results of the study of ways to optimize the technology of development of rock ore deposits are given. The fundamentals of a combined technology for the development of substandard reserves with an increase in the completeness of the use of mineral resources on a scientific basis are formulated. Recommendations are given for the design of technologies for underground mining of ore deposits of the type under consideration, optimized according to the criteria determined by modeling. An assessment of the resource potential of mining and metallurgical waste and recommendations for the development of the best available technologies for activating the components of concrete mixtures for the manufacture of goods is given. The results of the study of the processes of extraction of metals from ores and man-made raw materials, including using mechanochemical technology of extraction of metals in a disintegrator and combined technologies of processing of non-conditioned ores and waste of their enrichment are presented.

Number of views: 507
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ISSN 1998-4502 (Print)                                                            ISSN 2499-975Х (Online)