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Date submitted2022-09-27
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Date accepted2023-04-03
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Date published2023-12-25
The study of displacing ability of lignosulfonate aqueous solutions on sand packed tubes
This paper presents the findings of laboratory studies of rheological properties and oil displacing ability of aqueous solutions of technical grade lignosulfonate done on the sand packed tube models. The solutions containing lignosulfonate can be useful as displacement agents in development of watered reservoirs with heterogeneous porosity and permeability. When used at high concentrations, technical grade lignosulfonate can achieve selective shut-off while maintaining the reservoir pressure. The oil displacement efficiency is improved by means of redistributing the flows and selective isolation of high-permeability zones. The use of such compositions allows increasing the sweep of low-permeability reservoir zones by created pressure differential and displacing the residual oil.
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Date submitted2022-08-10
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Date accepted2023-02-28
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Date published2024-02-29
Selection of the required number of circulating subs in a special assembly and investigation of their performance during drilling of radial branching channels by sectional positive displacement motors
The task of sludge removal to the surface during construction of directional and horizontal wells and strongly curved radial channels is relevant. For stable operation of technical system “Perfobore”, it is proposed to use a circulating sub that ensures efficient cleaning of channel wellbore from the drilled rock. Two schemes of technical system “Perfobore” are considered, consisting of two seven-meter coiled tubing, a positive displacement motor, a bit and one circulating sub in the first scheme and two subs in the second scheme. For each of the schemes CFD modeling was implemented to determine values of pressure and speed. It was found out that the use of two circulating subs in the assembly is more efficient. In order to confirm the numerical experiment, bench tests were carried out. It was determined that the designed circulating sub can eject up to 25 % of pumped drilling fluid. The bench tests of full-size technical system “Perfobore” for drilling 14-meter channels with two circulating subs showed that the axial load on positive displacement motor produced by hydraulic loader was 3000 N and pressure drop depending on flow rate was 1.5-2.0 MPa. This allows the motor to operate at maximum power.
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Date submitted2022-07-15
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Date accepted2022-12-13
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Date published2023-02-27
Mathematical modelling of displacement during the potash ores mining by longwall faces
In favourable mining conditions, in particular at the Starobinskoye potash deposit (Belarus), longwall mining systems are used. They cause a high human-induced load on the subsoil, including intense deformation of the ground surface. The presented investigations are aimed at studying the dynamics of the ground surface displacement during the longwall face advance. Mathematical modelling was carried out in an elastic-plastic formulation with numerical implementation by the finite element method. The condition for the roof rocks collapse was opening of the contact between the seams when its boundaries were reached by shear fractures or formation of the tensile stresses area at the outcrop. With the working front advance, an increase in subsidence is observed, followed by its stabilization to a value determined by the process parameters of mining operations and the physical and mechanical properties of collapsed rocks. In this case, each point of the ground surface experiences sign-alternating horizontal deformations: when the front approaches, it causes tension, and when it moves away, compression. The obtained results of mathematical modelling are in good agreement with the data of instrumental measurements of the ground surface displacements, which indicates the adequate description of the rock mass deformation during the slice excavation of sylvinite seams by longwall faces.
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Date submitted2021-03-18
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Date accepted2021-11-30
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Date published2021-12-27
Deformations assessment during subway escalator tunnels construction by the method of artificial freezing of soil for the stage of ice wall formation
- Authors:
- Evgenii M. Volokhov
- Diana Z. Mukminova
The work is devoted to the study of the processes of displacement and deformation of the surface during the escalator tunnels construction of the subway by the method of artificial freezing of soils. The features of the construction and freezing technology, the rocks characteristics in which the escalator tunnels made are considered. The data of specially organized, full-scale surveying observations of deformations on the earth surface are presented. The main factors influencing deformation processes in the frozen strata of a layered inhomogeneous rock mass with inclined tunneling are determined, the complexity of the predictive task and the need to simplify the design scheme are shown. The work is focused on the assessment of the least studied geomechanical processes of soil heaving-uplifts and deformations during the periods of active and passive freezing stages. When studying the displacements processes of the earth surface and rock mass, the finite element method and analysis of the obtained data using field observations of displacements were used. A simplified calculation scheme is proposed for modeling, which allows taking into account the uneven influence of frozen rocks of an inhomogeneous layered rock mass with a large inclined tunneling. The satisfactory convergence of the data of field surveying observations on the earth surface and the results of modeling geomechanical processes for the period of active and passive freezing stages is shown. The proposed calculation scheme is recommended for the prediction of deformation at the stages of underground construction, characterized by the development of the most dangerous tensile deformations of buildings and structures on the surface.
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Date submitted2021-01-25
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Date accepted2021-02-22
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Date published2021-04-26
Conducting industrial explosions near gas pipelines
The problem to ensure the safety of objects which are in the area of blasting operations, ensuring the destruction of hard rocks, remains relevant. The article presents the results of a large-scale experiment to determine the safe conditions for conducting drilling and blasting operations near the active gas pipeline. The simplest and most reliable way to ensure the safety of the protected object from seismic impact is to reduce the intensity of the seismic wave, which is achieved by changing the parameters of drilling and blasting operations. This requires research to determine the impact of blasting operations on the parameters of seismic waves and the development of methods for measuring these parameters. The paper presents a detailed analysis of the seismic blast wave impact on the displacement of the ground and the model gas pipeline. The features of seismic monitoring during blasting operations near the active gas pipeline are shown. The seismic coefficients and attenuation coefficient of seismic waves are determined. It is proved that the readings of the seismic receivers on the surface and in the depth of the massive differ by two or more times.
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Date submitted2020-05-05
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Date accepted2020-10-05
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Date published2020-11-24
Assessment of the Influence of Water Saturation and Capillary Pressure Gradients on Size Formation of Two-Phase Filtration Zone in Compressed Low-Permeable Reservoir
The paper examines the influence of capillary pressure and water saturation ratio gradients on the size of the two-phase filtration zone during flooding of a low-permeable reservoir. Variations of water saturation ratio s in the zone of two-phase filtration are associated with the pressure variation of water injected into the reservoir; moreover the law of variation of water saturation ratio s ( r , t ) must correspond to the variation of injection pressure, i.e. it must be described by the same functions, as the functions of water pressure variation, but be subject to its own boundary conditions. The paper considers five options of s ( r , t ) dependency on time and coordinates. In order to estimate the influence of formation and fluid compressibility, the authors examine Rapoport – Lis model for incompressible media with a violated lower limit for Darcy’s law application and a time-dependent radius of oil displacement by water. When the lower limit for Darcy’s law application is violated, the radius of the displacement front depends on the value of capillary pressure gradient and the assignment of s function. It is shown that displacement front radii contain coefficients that carry information about physical properties of the reservoir and the displacement fluid. A comparison of two-phase filtration radii for incompressible and compressible reservoirs is performed. The influence of capillary pressure gradient and functional dependencies of water saturation ratio on oil displacement in low-permeable reservoirs is assessed. It is identified that capillary pressure gradient has practically no effect on the size of the two-phase filtration zone and the share of water in the arbitrary point of the formation, whereas the variation of water saturation ratio and reservoir compressibility exert a significant influence thereupon.
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Date submitted2020-05-29
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Date accepted2020-09-16
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Date published2020-11-24
Numerical modeling of a double-walled spherical reservoir
Extensive and important class of multilayer shell structures is three-layer structures. In a three-layer structure, a rigid filler plays an important role, due to which the bearing layers are spaced that gives the layer stack high rigidity and durability with a relatively low weight. By combining the thicknesses of the bearing layers and the filler, the desired properties of a three-layer shell structure can be achieved. Compared with traditional single-walled, three-layer construction has increased rigidity and durability, which allows reducing the thickness and weight of the shells. In order to reduce the metal content of the spherical reservoir for storing liquefied gases, this work considers the design of a double-walled reservoir, in which the inter-wall space is filled with reinforced polyurethane. Numerical modeling made it possible to determine the parameters of the stress-strain state of the structure with an error of no more than 5 %. It has been established on the example of a reservoir with a volume of 4000 m 3 that the spatial structure of the spherical reservoir wall can reduce the metal content up to 19 %. Field of application for the research results is the assessment of the stress-strain state of spherical reservoirs at their designing. Method for building the structure of a double-walled spherical reservoir in the SCAD software has been developed, which allows calculating the stress-strain state (SSS) by the finite element method. Numerical model of a double-walled spherical reservoir has been developed. It was found that to obtain calculation results with an error of P ≤ 5 % the size of the final element should not exceed 300×300×δ mm. Design of a double-walled spherical reservoir was investigated. Design parameters have been established to ensure the operational reliability of the structure with a decrease in metal content in comparison with a single-wall reservoir by 19 %.
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Date submitted2015-07-14
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Date accepted2015-09-09
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Date published2016-02-24
Engineering and geomechanical forecast for waste disposal in underground caverns including earthquake-prone zones
- Authors:
- O. V. Kovalev
The article aims at obtaining representative scientifically based data to determine parameters of a necessary-safe condition of the rock massif (RM) in underground waste diposal caverns zones, including earthquake-prone zones. The main requirements for underground caverns for hazardous waste disposal and for their construction technology are described. The subject of the research is underground solution caverns in halogen rocks. Data for justification of safe waste disposal conditions in underground salt caverns and its stages are presented. A complex approach to the solution of the research problem is described. The main aspects of dynamic influence of seismic waves on underground caverns stability are considered. Taking into account seismic-risk zoning data on the research region some significant parameters of a possible seismic impact on the experimental cavern are calculated. The article points out the necessity of superincumbent rock and surface displacement assessment for the experimental site zone using the suggested complex approach and including the analysis of surveying data and results of rock mass geomechanical modeling.
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Date submitted2010-07-10
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Date accepted2010-09-04
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Date published2011-03-21
Experimental research of the train aerodynamic resistance
- Authors:
- V. A. Pleskunov
In paper the technique of definition of aerodynamic resistance of the train, a being main component of a piston pressure is resulted. The urgency of the given theme is caused by essential influence of a piston pressure on distribution of fresh air on a tunnel and accordingly on safe operation of railway tunnels.
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Date submitted2009-10-14
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Date accepted2009-12-28
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Date published2010-09-22
Geodynamic model of hydrogen sulphide’s formation in natural gas and oil in the process of rocks impulsive compression under conditions оf earthquakes
- Authors:
- A. V. Petukhov
By experiments, conducted on the installation like Bridgeman’s anvil it was determined that under conditions of high pressure, displacement deformations and elastic wave’s effect of short duration, sulphates are reclaimed by hydrocarbons. As a result of this reaction sulphur and hydrogen sulphide are produced.
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Date submitted2009-10-13
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Date accepted2009-12-14
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Date published2010-09-22
The evaluation of geodynamic consequences оf long-term exploration of lower cretaceous sediments at the Yamburg oil-gas condensate field with join of additional wells
Within the framework of the engineering design of the join up of additional wells of Lower Cretaceous sediments at the Yamburg oil-gas condensate field the evaluation of geodynamic consequences of long-term exploitation of the mentioned field was performed, as well as the hazardous geodynamic process permanent survey program was developed.
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Date submitted2009-10-04
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Date accepted2009-12-19
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Date published2010-09-22
Modeling of the volumetric stress-strain condition of the rock massive in the near mine which are crossing zone of weakening
- Authors:
- A. G. Protosenya
- D. N. Petrov
- M. G. Popov
According to geological data which was received at the Yakovlevsky deposit, the volumetric model was developed. This model taking into consideration the driving of the mine through zone of weakening. During the analysis of the stress-strain condition near the mine the character of distribution and numerical results of tangential and longitudinal stresses have been revealed. The zone of weakening affects to the distribution of stresses and displacements around the mine. To select the parameters of the lining support it is necessary to take into consideration weakenings and contacts in the ore massive and the distance for these zones.
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Date submitted2009-07-09
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Date accepted2009-09-03
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Date published2010-04-22
The stress-strain state of the massive of the loose ores in the Yakovlevsky deposit around the minings which were drilled with the combines or with drilling-blast technology
The article presents the consistent patterns of the changes in stress-strain state of the massive by the minings of the first stage of protective overlapping in the Yakovlevsky deposit. The change of the stress-strain condition of the rock massive, which is weaked by the mining was determined by the method of finite elements. The stresses distribution in the massive, the displacement of the contour of the minings, the size of conditional zones of non-linear deformations has been obtained. For stoping passes at the first stage the cutting with combine and application of fastening with the anchors has been suggested.
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Date submitted2009-07-21
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Date accepted2009-09-28
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Date published2010-04-22
The determination of the volume stress-strain conditions of the rock massive with the circular outline mining ensrined with the anchors
- Authors:
- A. G. Protosenya
- N. A. Belyakov
In the article the analysis of consolidating effect from application of the anchor fastening, which using at driving of transport tunnels in the conditions of North Caucasus is produced. The change of the stress-strain condition of the rock massive, which is weaked by the mining of the circular outline is certain with the finite-elements method. On the basis of the executed design the row of graphic dependences, which describes changing of the sizes of limitary areas depending on strength and deformational properties of the rocks. Due to results of the conducted work the direction of further researches is seted.
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Date submitted2009-07-09
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Date accepted2009-09-01
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Date published2010-04-22
Method of calculation stability of the open pit edges
- Authors:
- A. V. Chebakov
During the opencast mining operations with bating and opening-up of new horizons as a result of the process duration in the near-edge rock mass, fatigue accumulates, which leads to slope deformations in the form of slide rocks, rock falls, roof breaks, and, in some cases, large-scale landslides. Given that the open pit edges are complex engineering structures, on the state of which mining operations effectiveness and safety depend, their stability control is a very urgent problem.
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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 submitted2009-07-06
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Date accepted2009-09-18
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Date published2010-04-22
Simulation of the stress-strain state forming around the vertical mine in the field of tectonically fractured massif
- Authors:
- D. Yu. Dordzhiev
The influence of the front clean up of stress-strain state around a vertical mine of a tectonically fracture massif for a uranium deposit «Antey» is considered. By means of computer simulation it’s have been confirmed by field observations.
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Date submitted1950-07-11
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Date accepted1950-09-30
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Date published1951-04-30
On fault-type displacements in cover structures
- Authors:
- I. N. Ushakov
The described displacements belong to a special type of fault tectonics, which occurs in cover structures and develops in them as a result of movements of the underlying rigid base. Therefore, displacements of this type are of interest as a characteristic example of tectonics manifestation in the coal-bearing strata of the Lower Tertiary age. A general idea of the nature of the manifestation of displacements is given by the schematic map of displacements and outcrops of coal seams (Fig. 1) and the geological section (Fig. 2). The coal-bearing strata of the Lower Tertiary age (Fig. 2) unconformably lies on the eroded surface of Mesozoic rocks. It is composed mainly of sandy clayey rocks. The underlying Mesozoic rocks in the area of contact with coal-bearing deposits are represented by destroyed conglomerate and quartz-feldspar sandstones.