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Date submitted2024-03-20
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Date accepted2024-11-07
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Date published2025-04-25
Analysis of the stress state of rocks transformation near a horizontal well during acid treatment based on numerical simulation
The article presents an overview of the assessment and modelling of the stress state of rocks in the near-wellbore zone of horizontal wells during acid stimulation of the formation for improving the efficiency of oil and gas field development. A numerical finite element model of near-wellbore zone of the reservoir drilled by a horizontal section was compiled using one of oil fields in the Perm Territory as an example. The distribution of physical and mechanical properties of the terrigenous reservoir near the well was determined considering transformation under the action of mud acid for different time periods of its injection. Multivariate numerical simulation was performed and the distribution of horizontal and vertical stresses in near-wellbore zone was determined with regard for different values of pressure drawdown and changes in stress-strain properties depending on the area of mud acid infiltration. It was found that a change in elastic modulus and Poisson's ratio under the influence of acid led to a decrease in stresses in near-wellbore zone. Analysis of the stress distribution field based on the Coulomb – Mohr criterion showed that the minimum safety factor of rock even after the effect of mud acid was 1.5; thus, under the considered conditions of horizontal well modelling, the reservoir rock remained stable, and no zones of rock destruction appeared.
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Date submitted2024-07-28
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Date accepted2024-11-26
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Date published2024-12-12
From import substitution to technological leadership: how local content policy accelerates the development of the oil and gas industry
- Authors:
- Oleg V. Zhdaneev
- Ivan R. Ovsyannikov
Achieving technological sovereignty implies accelerating innovation and reducing import dependence. An effective tool for addressing these challenges is local content policy (LCP). The purpose of this study is to assess the impact of LCP on innovation activity in oil and gas companies and to provide recommendations for enhancing the effectiveness of this policy in Russia. The paper analyzes the influence of LCP on innovation levels in the oil and gas sector, drawing on examples from 10 countries. A positive short-term impact of LCP on innovation was identified in Brazil, Malaysia, and Saudi Arabia, with long-term effects observed in China and South Africa. Recommendations for improving the effectiveness of LCP in Russia are supplemented with a methodology for calculating the level of technological sovereignty. A refinement of the method for solving the «responsiveness» problem, incorporating the level of localization, has been proposed.
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Date submitted2023-03-14
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Date accepted2023-10-25
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Date published2024-04-25
Predictive assessment of ore dilution in mining thin steeply dipping deposits by a system of sublevel drifts
The purpose of research is the study of stress-strain state of marginal rock mass around the stope and predictive assessment of ore dilution with regard for changes in ore body thickness in mining thin ore deposits on the example of the Zholymbet mine. Study of the specific features of the stress-strain state development was accomplished applying the methodology based on numerical research methods taking into account the geological strength index (GSI) which allows considering the structural features of rocks, fracturing, lithology, water content and other strength indicators, due to which there is a correct transition from the rock sample strength to the rock mass strength. The results of numerical analysis of the stress-strain state of the marginal part of the rock mass using the finite element method after the Hoek – Brown strength criterion made it possible to assess the geomechanical state in the marginal mass provided there are changes in ore body thickness and to predict the volume of ore dilution. It was ascertained that when mining thin ore deposits, the predicted value of ore dilution is influenced by the ore body thickness and the GSI. The dependence of changes in ore dilution values on the GSI was recorded taking into account changes in ore body thickness from 1 to 3 m. Analysis of the research results showed that the predicted dimensions of rock failure zone around the stopes are quite large, due to which the indicators of the estimated ore dilution are not attained. There is a need to reduce the seismic impact of the blasting force on the marginal rock mass and update the blasting chart.
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Date submitted2022-11-04
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Date accepted2023-03-03
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Date published2023-04-25
Efficiency of acid sulphate soils reclamation in coal mining areas
During the development of coal deposits, acid mine waters flowing to the surface cause the formation of acid sulphate soils. We study the effectiveness of soil reclamation by agrochemical and geochemical methods at the site of acid mine water discharge in the Kizel Coal Basin, carried out in 2005 using alkaline waste from soda production and activated sludge. A technosol with a stable phytocenosis was detected on the reclaimed site, and soddy-podzolic soil buried under the technogenic soil layer with no vegetation on the non-reclaimed site. The buried soddy-podzolic soil retains a strong acid рН concentration Н 2 О = 3. A high content of organic matter (8-1.5 %) is caused by carbonaceous particles; the presence of sulphide minerals reaches a depth of 40 cm. Technosol has a slightly acid pH reaction H 2 O = 5.5, the content of organic matter due to the use of activated sludge is 19-65 %, the presence of sulphide minerals reaches a depth of 20-40 cm. The total iron content in the upper layers of the technosol did not change (190-200 g/kg), the excess over the background reaches 15 times. There is no contamination with heavy metals and trace elements, single elevated concentrations of Li, Se, B and V are found.
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Date submitted2021-12-16
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Date accepted2022-04-07
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Date published2022-07-13
The Upper Kotlin clays of the Saint Petersburg region as a foundation and medium for unique facilities: an engineering-geological and geotechnical analysis
- Authors:
- Regina E. Dashko
- Georgiy A. Lokhmatikov
The article reviews the issues concerned with correctness of the engineering-geological and hydrogeological assessment of the Upper Kotlin clays, which serve as the foundation or host medium for facilities of various applications. It is claimed that the Upper Kotlin clays should be regarded as a fissured-block medium and, consequently, their assessment as an absolutely impermeablestratum should be totally excluded. Presence of a high-pressure Vendian aquifer in the lower part of the geological profile of the Vendian sediments causes inflow of these saline waters through the fissured clay strata, which promotes upheaval of tunnels as well as corrosion of their lining. The nature of the corrosion processes is defined not only by the chemical composition and physical and chemical features of these waters, but also by the biochemical factor, i.e. the availability of a rich microbial community. For the first time ever, the effect of saline water inflow into the Vendian complex on negative transformation of the clay blocks was studied. Experimental results revealed a decrease in the clay shear resistance caused by transformation of the structural bonds and microbial activity with the clay’s physical state being unchanged. Typification of the Upper Kotlin clay section has been performed for the region of Saint Petersburg in terms of the complexity of surface and underground building conditions. Fissuring of the bedclays, the possibility of confined groundwater inflow through the fissured strata and the consequent reduction of the block strength as well as the active corrosion of underground load-bearing structures must be taken into account in designing unique and typical surface and underground facilities and have to be incorporated into the normative documents.
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Date submitted2019-04-27
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Date accepted2019-07-10
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Date published2019-10-23
Estimation of Rock Mass Strength in Open-Pit Mining
The paper presents results of an experimental study on strength characteristics of the rock mass as applied to the assessment of open-pit slope stability. Formulas have been obtained that describe a correlation between ultimate and residual strength of rock samples and residual shear strength along the weakening surface. A new method has been developed to calculate residual interface strength of the rock mass basing on data from the examination of small-scale monolith samples with opposing spherical indentors. A method has been proposed to estimate strength characteristics (structural weakening coefficients and internal friction angles) of the fractured near-slope rock mass. The method relies on test data from shattering small-scale monolith samples with spherical indentors, taking into ac- count contact conditions along the weakening surface, and can be applied in the field conditions. It is acceptable to use irregular-shaped samples in thetests.
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Date submitted2019-04-30
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Date accepted2019-07-16
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Date published2019-10-23
Salt Rock Deformation under Bulk Multiple-Stage Loading
- Authors:
- I. L. Pankov
- I. A. Morozov
The paper presents experimental justification of the possibility to use bulk multiple-stage loading to study the process of salt rock deformation in the laboratory conditions. Results of comparative tests between bulk multiple- stage and single-stage loading of salt rock samples are demonstrated. The paper contains results of research on the rate of lateral pressure and its impact on strength limit and residual strength limit of sylvinite, estimated using single- stage and multiple-stage methods. Research results demonstrate how the rate of lateral pressure impacts dilatancy boundary of salt rocks. Analysis of how the loading method influences certificate parameters of Mohr-Coulomb strength of sylvinite has been carried out. The dynamics of elastic modulus in the process of salt rock deformation is analyzed depending on the rate of lateralpressure. It is demonstrated how the method of multiple-stage loading adequately reflects the processes of salt rock de- formation and decomposition, and facilitates not only lowering impact of sample’s inner structure heterogeneities on the experimental results, but also significant reduction in the required amount of rock material.
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Date submitted2018-11-09
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Date accepted2019-01-08
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Date published2019-04-23
Effect of chalk thermal treatment mode on its strength
- Authors:
- V. A. Lipin
- D. A. Trufanov
Natural chalk is characterized by a fine-grained structure. The processing of chalk in conditions traditional for calcium carbonate baking is accompanied by its almost destruction and the formation of a huge amount of dust. The paper presents strength characteristics of chalk and chalky stone baking obtained with different temperature-time conditions of heating the raw material to a temperature of 450-600 °C. The uniaxial compression method was used to determine the strength depending on variable factors. Based on the experimental data, a model was constructed that determines the dependence of chalk strength on time and heating temperature. In the temperature range of 450-600 °C, the strength of chalk stone increases with increasing temperature and decreases with the increasing heating rate. In the process of isothermal heating, several factors will immediately affect the strength of a chalky stone: the formation and growth of calcite crystals, the evaporation of water, and the agglomeration of calcite grains. With an increase in the heating temperature from 450 to 600 °C, the average size of the crystals significantly increases and crystals with an estimated size of more than 4 microns are detected. An increase in the size of crystals is associated with an increase in their growth rate. The agglomeration of grains occurs at a temperature of 600 °C.
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Date submitted2018-08-29
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Date accepted2018-10-25
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Date published2019-02-22
The study of the effect of temperature on the ability of metals to accumulate energy during their plastic deformation
The subject of research is the surface layer of highly loaded parts, friction units of mining machines and equipment. The article presents a theoretical analysis of the factors that determine the ability of the material of the surface layer of parts to accumulate energy in the process of plastic deformation. It is suggested that the activation character of the accumulation of energy by metals. Based on the theory of diffusion, it was shown that the mobility of atoms, as well as the accumulated energy, are determined by the ratio of the test temperature to the melting temperature.
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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 submitted2016-09-03
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Date accepted2016-11-24
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Date published2017-02-22
Research of compression strength of fissured rock mass
- Authors:
- A. G. Protosenya
- P. E. Verbilo
The article examines a method of forecasting strength properties and their scale effect in fissured rock mass using computational modelling with final elements method in ABAQUS software. It shows advantages of this approach for solving tasks of determining mechanical properties of fissured rock mass, main stages of creating computational geomechanic model of rock mass and conducting a numerical experiment. The article presents connections between deformation during loading of numerical model, inclination angle of main fracture system from uniaxial and biaxial compression strength value, size of the sample of fissured rock mass and biaxial compression strength value under conditions of apatite-nepheline rock deposit at Plateau Rasvumchorr OAO «Apatit» in Kirovsky region of Murmanskaya oblast. We have conducted computational modelling of rock mass blocks testing in discontinuities based on real experiment using non-linear shear strength criterion of Barton – Bandis and compared results of computational experiments with data from field studies and laboratory tests. The calculation results have a high-quality match to laboratory results when testing fissured rock mass samples.
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Date submitted2009-08-17
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Date accepted2009-10-12
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Date published2010-02-01
Complex geological engineering and geoenvironmental monitoring as a basis for creation of strategy of Saint Petersburg architectural and historical monuments conservation
- Authors:
- A. V. Shidlovskaya
In the paper concept and structural of complex engineering geological and geoenvironmental monitoring of architectural and historical monuments are considered. The specificity of engineering geological and hydrogeological conditions by the example of the Isaac Cathedral, the Kazan Cathedral and the Peter and Paul Cathedral is analyzed. The geoenvironmental condition of architectural and historical monuments underground space is estimated. The factors which influence on monuments deformation due to the high degree of underground space transformation and activity of negative natural and technogenic processes are shown. The system of impact monitoring of the Isaac Cathedral, the Kazan Cathedral and the Peter and Paul Cathedral is proposed.
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Date submitted2009-07-18
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Date accepted2009-09-30
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Date published2010-04-22
Account of stress gradients in rock mass in designing of mining constructions
- Authors:
- S. V. Suknyov
- M. D. Novopashin
Using the gradient approach the criteria of shear and tensile cracking are developed in compression under conditions of stress concentrations near mine workings. Considering the size effect, a function type of local strength is determined, expressions for critical pressure are derived and comparison between analytical and experimental data is performed.
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Date submitted2009-07-24
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Date accepted2009-09-16
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Date published2010-04-22
Determination of indices of strength certificate оf rocks using the method of specimens failure with spherical indentors
- Authors:
- V. A. Korshunov
- Yu. M. Kartashov
- V. A. Kozlov
The method has been developed for the determination of indices of strength certificate of rocks using the technique of specimen’s failure with oncoming spherical indentors. This method is based on the assessment of ultimate stresses acting in the tensile plane and within the zones of failured rocks under action of indentors at the moment of sample splitting. Formulas were obtained for calculation of indices of strength certificate, i.e. cohesion and angles of internal friction under tensile compression and nonuniform triaxial compression, ultimate strength in uniaxial compression and tension. This method is applicable in situ conditions.
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Date submitted2008-10-08
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Date accepted2008-12-08
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Date published2009-12-11
Georadar investigations of shallow depth оf geological section and engineering constructions
- Authors:
- V. V. Glazunov
- N. N. Efimova
The GPR-method showing high resolution, great performance and sensitivity to minor variations in the composition and conditions of soils and material has assumed a role of the leading geophysical method for looking at the upper part of the geological section. This paper presents the advanced directions of GPR application for engineering problems solution.
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Date submitted1958-03-07
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Date accepted1958-05-17
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Date published1958-05-09
К СТРАТИГРАФИИ ВЕРХНЕПРОТЕРОЗОЙСКОЙ ТОЛЩИ МЕТАМОРФИЧЕСКИХ ПОРОД ЮГО-ВОСТОЧНОЙ ЧАСТИ ТУВЫ
- Authors:
- Unknown
Верхнепротерозойская толща метаморфических пород на правобережье р. Эрзин, к западу от ее правого притока (р. Улар), А. В. Ильиным и В.М. Моралевым подразделяется на две серии: нижнюю — терригенную и верхнюю — карбонатную. В каждой из них выделяются по две свиты: тесхемская и мугурская, балактыкхемская и чартисская. Краткое описание разреза (снизу вверх) следующее…
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Date submitted1958-03-10
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Date accepted1958-05-23
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Date published1958-05-09
НЕКОТОРЫЕ ОСОБЕННОСТИ ГЕОЛОГИЧЕСКОГО СТРОЕНИЯ ОДНОГО ИЗ УЧАСТКОВ ЦЕНТРАЛЬНОГО РАЙОНА ДОНБАССА
- Authors:
- Unknown
В геологическом строении исследованной территории принимают участие породы свит.С 2 и С 3 угленосной толщи среднего карбона, которые выходят на поверхность в виде узкой (0,5—2,5 км) полосы вдоль оси Главной Донецкой антиклинали, именуемой в этой части Горловской. Севернее и южнее этой полосы на поверхность выходят породы вышележащих угленосных свит, образующих крылья складки. Породы здесь имеют крутое (50—65°) падение, а выходы их почти прямолинейно простираются в западно-северо-западном и восточно-юго-восточном направлениях. Осевая часть антиклинали усложнена мелкими складчатыми формами и большим количеством разрывных нарушений, различных по возрасту и характеру.