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Date submitted2024-05-15
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Date accepted2025-01-28
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Date published2025-04-30
Study of changes in the void space of core samples under cyclic loading
The subsurface state is explored and analysed by studying the core material. This is the basis for forecasts, construction and improvement of models. The reservoir properties of rocks obtained from the laboratory study of sample are subject to a system error caused by three main factors: rock selection in the zone of altered stress-strain state, rock removal from the thermobaric conditions of natural occurrence, and the measuring equipment error. A change in the natural stress-strain state of rocks occurs as a result of intervention in the formation system and the entire massif by constructing a well, creating overburden and depression. The rise of the core causes unloading from formation pressure to atmospheric one, natural saturation is lost, temperature conditions change. This affects the reservoir properties and rock injectivity. This study is aimed at investigating changes in the void space of the rock in formation conditions under cyclic loading. Based on the data obtained, a regression forecast of properties is made, excluding external influences. The article describes the results of experiments on multiple loading and unloading of water-saturated sandstone samples by geostatic pressure with precise control of the water displaced and returned to the void space. This method enables us to record the change in the internal void volume of the rock and, as a consequence, elastic and plastic deformations, the value of relaxation of elastic deformations. The dynamics of change in the coefficients of porosity and compressibility from the stress state cycle is estimated and the range of predicted porosity values of the rock in formation conditions is determined. For samples of permeable medium- to fine-grained sandstone, the obtained character of porosity change gives a forecast of the initial porosity in formation conditions of 20.19±0.61 %. Thus, the exclusion of human impact on porosity gives values 1.42 % higher than the results of standard laboratory studies.
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Date submitted2022-08-01
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Date accepted2022-11-17
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Date published2023-02-27
Use of machine learning technology to model the distribution of lithotypes in the Permo-Carboniferous oil deposit of the Usinskoye field
- Authors:
- Denis V. Potekhin
- Sergei V. Galkin
Permo-Carboniferous oil deposit of the Usinskoye field is characterized by an extremely complex type of the void space with intense cross-sectional distribution of cavernous and fractured rock. In this study, for this production site, the process of 3D geological modeling has been implemented. At the first stage, it provided for automated identification of reservoir volumes by comparing the data of core and well logging surveys; at the second stage, identification of rock lithotypes according to Dunham classification is performed on the basis of comparison of thin sections examination and well logging data. A large array of factual information enables the use of machine learning technology on the basis of Levenberg – Marquardt neural network apparatus toward achievement of our research goals. The prediction algorithms of reservoir and rock lithotype identification using well logging methods obtained on the basis of the training samples are applied to the wells without core sampling. The implemented approach enabled complementing the 3D geological model with information about rock permeability and porosity, taking into account the structural features of the identified lithotypes. For the Permo-Carboniferous oil deposit of the Usinskoye field, the volumetric zoning of the distribution of different rock lithotypes has been established. Taking into account the lithotypes identified based on machine learning algorithms, density and openness of fractures were determined, and fracture permeability in the deposit volume was calculated. In general, during the implementation, the machine learning errors remained within 3-5 %, which suggests reliability of the obtained predictive solutions. The results of the research are incorporated in the existing 3D digital geological and process model of the deposit under study.
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Date submitted2022-03-14
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Date accepted2022-06-20
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Date published2022-11-10
Model of a walking sampler for research of the bottom surface in the subglacial lake Vostok
Technologies and technical means for investigation of subglacial lakes in Antarctic is a new developing scientific and technical direction, which today has no clearly established methodology. Based on the developed technology of drilling a new access well to lake Vostok and its penetration as well as analysis of existing methods and devices for bottom sediment sampling, a basic model of a sampler with a walking-type mover, capable of moving along different trajectories and operating in a wide technological range, is proposed. The proposed device model is equipped with different actuators for sampling the bottom surface with different physical and mechanical properties. Based on the presented basic model of the walking sampler, a mathematical model of the device was developed, which was based on the theoretical mechanics methods. As a result of conducted research the dependencies were obtained, which allow making a scientifically justified choice of optimal values for geometric and force parameters of the walking sampler. A conceptual design of the walking sampler has been developed, taking into account the mutual location and coupling of its main components, the overall dimensions of the delivery tool, as well as the esthetic component of the device.
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Date submitted2022-01-31
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Date accepted2022-09-06
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Date published2022-11-10
Filtration studies on cores and sand packed tubes from the Urengoy field for determining the efficiency of simultaneous water and gas injection on formation when extracting condensate from low-pressure reservoirs and oil from oil rims
- Authors:
- Nikolay A. Drozdov
Oil rims as well as gas condensate reservoirs of Russia's largest Urengoy field are developed by depletion drive without formation pressure maintenance, which has led to serious complications in production of oil, gas and condensate. In addition, field development by depletion drive results in low values of oil and condensate recovery. These problems are also relevant for other oil and gas condensate fields. One of the possible solutions is simultaneous water and gas injection. Rational values of gas content in the mixture for affecting gas condensate fields and oil rims of oil and gas condensate fields should be selected using the data of filtration studies on core models. The article presents the results of filtration experiments on displacement of condensate and oil by water, gas and water-gas mixtures when simulating the conditions of the Urengoy field. Simultaneous water and gas injection showed good results in the experiments on displacement of condensate, residual gas and oil. It has been ascertained that water-gas mixtures with low gas content (10-20 %) have a better oil-displacement ability (9.5-13.5 % higher) than water. An experiment using a composite linear reservoir model from cemented core material, as regards the main characteristics of oil displacement, gave the same results as filtration experiments with sand packed tubes and demonstrated a high efficiency of simultaneous water and gas injection as a method of increasing oil recovery at oil and gas condensate fields.
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Date submitted2021-10-19
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Date accepted2021-11-30
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Date published2021-12-27
Potential technological solution for sampling the bottom sediments of the subglacial lake Vostok: relevance and formulation of investigation goals
The subglacial Lake Vostok in Antarctic is a unique natural phenomenon, its comprehensive study involves sampling of water and bottom surface rocks. For further study of the lake, it is necessary to drill a new access well and develop environmentally safe technologies for its exploration. This article discusses existing and potential technologies for sampling bottom surface rocks of subglacial lakes. All these technologies meet environmental safety requirements and are conducive for sampling. The authors have proposed an alternative technology, using a walking device, which, due to its mobility, enables selective sampling of rocks across a large area from a single access well. The principal issues, related to the implementation of the proposed technology, are investigated within this article. This report is prepared by a team of specialists with many years of experience in drilling at the Vostok Station in Antarctic and in experimental work on the design of equipment and non-standard means of mechanization for complicated mining, geological and climatic conditions.
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Date submitted2019-01-01
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Date accepted2019-03-03
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Date published2019-06-25
Strategic approach to assessing economic sustainability objects of mineral resources sector of Russia
The article gives a new definition of economic systems (ES) stability with its distinct strategic content. The main approaches to assessment of sustainability, based on the use of strategic cards, including Balanced Scorecard (BSC), are considered. Synchronous management of effectiveness, risks and chances of the ES exhausts the agenda of managing economic sustainability of ES when it operates in the face of a wide range of challenges. BSC in mineral resources sector (MRS) can be built during the aggregation of BSC by industry and individual enterprises. The use of 4 ´ 6 matrix formalism is proposed as the main tool for modeling economic sustainability of the ES.
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Date submitted2018-07-04
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Date accepted2018-09-17
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Date published2018-12-21
Secondary dispersion halos as a prospecting indicator of platinum metal mineralization on the example of the Kamenushinsky massif (Middle Urals)
- Authors:
- A. M. Minibaev
The paper discusses the results of bulk rock geochemical sampling of the Kamenushinsky massif eluvial-deluvial deposits and the massifs bedrocks spectral analysis data. Evaluation of secondary dispersion halos using two-dimensional modeling and multivariate statistic processing of the results have allowed establishing the spatial collocation of platinum and chromium anomalies and high correlation between these elements. These facts confirm the considerable contribution of chromite-platinum mineralization to the primary ores of the entire Kamenushinsky massif. The geological observations and rocks chemical composition analysis has revealed that uranium and barium anomalies are associated with the areas of gabbro and granitoids dike bodies. The insignificant overlapping of uranium and barium anomalies with platinum and chromium ones, as well as the negative correlation between these two groups of elements, is inconsistent with earlier conclusions on the spatial association of platinum mineralization with gabbro and granitoids dikes and a possible connection between these dikes and platinum metal mineralization zones.
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Date submitted2018-01-01
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Date accepted2018-03-24
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Date published2018-06-22
Complex petrophysical correction in the adaptation of geological hydrodynamic models (on the example of Visean pool of Gondyrev oil field)
- Authors:
- V. A. Repina
- V. I. Galkin
- S. V. Galkin
The authors review a method of combined porosity and volume density correction in the process of modeling the distribution of reservoir permeability. Basing on petrophysical investigations of core samples from Bashkir fold deposits, an association between rock porosity, density and permeability has been analyzed. Significant correlation has been observed for the above mentioned parameters in porous collectors in contrast to reduced correlation for dense rocks and intervals of anomalously high poroperm characteristics. For terrigene porous collectors the authors propose a model of permeability assessment based on combined porosity and density correction. A modified model was developed for Visean pool of Gondyrev oil field, where collector permeability had been calculated as a function of rock porosity and density. The modified model has been compared to the conventional one; significant differences have been detected. In the modified version maximum permeability is associated with the southern part of the pool, whereas the conventional method points out the central part and predicts lowering permeability closer to the periphery. Geological model in the modified version is more homogenous than the conventional one and has no sharp peaks and valleys. The calculations have been made that reproduce the history of field development for both permeability volumes. Authors demonstrate that total oil production obtained using the modified model has a much better correlation with the actual data. The best results from using suggested method apply to the initial stage of development due to better convergence of high-rate wells. On the whole, comparison of two methods shows that for the purposes of production history adaptation the modified model is significantly better than the conventional one. Hence, the method of density correction allows for better justification of differences in the lithology of Visean collectors, which ultimately results in higher accuracy of data on residual oil reserves in the deposit.
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Date submitted2016-11-21
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Date accepted2017-01-23
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Date published2017-04-14
Prospects of obtaining samples of bottom sediments from subglacial lake Vostok
- Authors:
- N. I. Vasilev
- G. L. Leichenkov
- E. A. Zagrivnyi
The paper proves the timeliness of obtaining and examining bottom sediments from subglacial Lake Vostok. Predictive geological section of Lake Vostok and information value of bottom sediments have been examined. Severe requirements towards environmental security of lake examinations and sampling of bottom sediments rule out the use of conventional drilling technologies, as they would pollute the lake with injection liquid from the borehole. In order to carry out sampling of bottom sediments from the subglacial lake, it is proposed to use a dynamically balanced tool string, which enables rotary drilling without any external support on borehole walls to transmit counter torque. A theoretical analysis has been carried out to assess the operation of the tool string, which is a two-mass oscillatory electromechanical system of reciprocating and rotating motion (RRM) with two degrees of freedom.
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Date submitted2015-08-21
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Date accepted2015-10-24
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Date published2016-04-22
Results of the 5G borehole drilling at russian antarctic station «Vostok» and researches of ice cores
- Authors:
- N. I. Vasilev
- A. N. Dmitriev
- V. Ya. Lipenkov
We produce an information about results and features of the 5G borehole drilling in Antarctic layer at Russian station Vostok. Main regularities of the change structured and physical properties by Antarctic ice layer depth, which determine mechanical and reological properties if ice, which influence to sinking of a borehole and to the maintaining of it in a working condition, the safe and competitive technologies creation for drilling of strong ice layers and the environmentally safe technology of the subglacial reservoirs unsealing. We also produce results of the ice cores researching and the paleoclimatic raws construction, which are reconstructed by the ice cores researching from Vostok station, which is compared with isotopic graph. This graph describes changes of World ocean level.
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Date submitted2015-07-05
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Date accepted2015-09-01
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Date published2016-02-24
Substantiation of intrastratal water shutoff technology in low permeability reservoirs
- Authors:
- M. K. Rogachev
- A. O. Kondrashev
The article presents the results of the filtration tests of the developed polymeric waterproofing compound GPS-1, which is a mixture of a water-alkaline hydrolyzed acryl-containing polymer solution with a nonionic surfactant. The obtained results indicate significant improvements of main operational parameters – penetrating and water-insulating power of the developed polymeric composition GPS-1 in comparison with the original one: addition of the nonionic surfactant reduced the pressure gradient of injection twice. Also, considerable (5 times) increase of the residual resistance factor, that is explained by deeper and more uniform penetration of the solution into the porous medium and the corresponding raise of isolation efficiency of pore channels, is established. Experiments on the model of a heterogeneous oil-filled formation showed that after the injection of the polymeric solution water mobility decreases in a highly porous interlayer and increases in a low-permeability interlayer indicating a redistribution of filtration flows in the model of a heterogeneous bed. The decrease of water mobility in a high-permeability zone contributes to the leveling of the displacement front and, ultimately, the additional extraction of oil from the less permeable area. As a result of the complex of filtration tests conducted, the efficiency of the developed polymeric composition GPS-1 for the regulation of filtration flows in low-permeability heterogeneous reservoirs is proved.
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Date submitted2013-07-10
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Date accepted2013-09-14
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Date published2014-03-17
Quality management of brown coal at open-pit mine in the presence of several consumers with varios requirements to it
- Authors:
- M. M. Yakubovskii
- K. Drebenshtedt
The article considers main stages of mine planning and modern methods of quality management at open-pit coal mines in Germany. The object of research is the company «MIBRAG GmbH» producing brown coal and providing them a wide range of consumers which have dif-ferent demands to the coal’s quality.
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Date submitted2009-09-08
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Date accepted2009-11-15
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Date published2010-06-25
Some peculiarities of english for specific purposes course development
- Authors:
- I. S. Lebedeva
The paper involved deals with the challenge Russian system of higher education faces. Special attention is paid to the core principles of ESP course development.
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Date submitted2008-10-16
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Date accepted2008-12-24
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Date published2009-12-11
Procedures and techniques for operation of the new automatic core orientator
- Authors:
- Yu. T. Morozov
The most similar prototype models of foreign and domestic core orientators have been analyzed, and a model of a new automatic core orientator created by the author is presented. It provides continuous drawing of three lines on1,5 metercore surface section by diamond cutters in borehole drilling, secures accurate core orientation, decrease in time and general costs of this work.
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Date submitted2008-10-11
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Date accepted2008-12-19
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Date published2009-12-11
The development of the effective method for sampling of native-state core in natural gashydrate deposits
- Authors:
- V. K. Chistyakov
Gas hydrates – the firm crystal connections of water and low-molecular waterproof natural gases such as carbohydrates (mainly methane), СО 2 , N 2 and others. At present, time exploitation of the Messoyahsk (Russia) and Mallik (Canada) deposits of gas hydrates is conducted actively. The further perfection of prospecting methods in the field of studying gas hydrate containing sediments in round extent depends on improvement of methods for native-state core sampling from these sediments.