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Date submitted2023-05-19
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Date accepted2024-03-05
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Date published2024-08-26
Development and research of backfill compounds with improved elastic and strength properties for oil and gas well lining
This article describes operations from the well construction cycle where the cement rock behind the casing is subjected to dynamic action (impacts of the drill stem during drilling and normalization of the cement sleeve, secondary drilling operations, hydraulic fracturing, etc.). The developed cement mortar compositions were tested following API 10B-2, API 10B-6, API STD-65-2, and GOST 28985-91 standards. The composition of the cement system without the use of imported components (CM-5) was developed, which improved elastic and strength properties compared to existing industry solutions. An improvement in the elastic and strength features and technological properties of cement rock when using epoxy resins was identified, the optimal composition of the cement-and-epoxy grout was determined, and the internal structure of the formed backfill rock, its permeability, and porosity were studied.
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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 submitted2022-06-20
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Date accepted2022-10-07
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Date published2022-11-03
Evaluation of deformation characteristics of brittle rocks beyond the limit of strength in the mode of uniaxial servohydraulic loading
One of the most reliable methods for assessing the physical and mechanical properties of rocks as a result of their destruction are laboratory tests using hard or servo-driven test presses. They allow to obtain reliable information about changes in these properties beyond the limit of compressive strength. The results of laboratory tests of rich sulfide ore samples are presented, which made it possible to obtain graphs of their extreme deformation. Both monolithic samples and samples with stress concentrators in the form of circular holes with a diameter of 3, 5 and 10 mm were tested. It was revealed that during the destruction of the samples, the modules of elasticity and deformation decrease by 1.5-2 times, and in the zone of residual strength – by 5-7 times.
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Date submitted2021-09-29
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Date accepted2022-05-11
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Date published2022-07-13
Tensor compaction of porous rocks: theory and experimental verification
Compaction in sedimentary basins has been traditionally regarded as a one-dimensional process that ignores inelastic deformation in directions orthogonal to the active load. This study presents new experiments with sandstone demonstrating the role of three-dimensional inelastic compaction in cyclic true triaxial compression. The experiments were carried out on the basis of a triaxial independent loading test system in the Laboratory of Geomechanics of the Ishlinsky Institute for Problems in Mechanics of the Russian Academy of Science. The elastic moduli of the material were estimated from the stress-strain curves and the elastic deformations of the sample in each of the three directions were determined. Subtracting the elastic component from the total deformation allowed to show that inelastic compaction of the sandstone is observed in the direction of active loading, whereas in the orthogonal directions there is a expansion of the material. To describe the three-dimensional nature of the compaction, a generalization of Athy law to the tensor case is proposed, taking into account the role of the stress deviator. The compaction tensor and the kinetic equation to describe the evolution of inelastic deformation, starting from the moment of the load application are introduced. On the basis of experiments on cyclic multiaxial compression of sandstone, the identification and verification of the constructed model of tensor compaction were carried out. The possibility of not only qualitative, but also quantitative description of changes in inelastic deformation under complex cyclic triaxial compression is shown.
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Date submitted2021-04-06
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Date accepted2022-04-27
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Date published2022-07-13
Experimental study on the effect of rock pressure on sandstone permeability
The results of laboratory studies to determine the effect of effective stress on the permeability of sandstone are presented. During the test, the samples were subjected to a stepwise increase or decrease of the effective stress (at a constant pore pressure) in a specified step. The values of rock permeability at different values of effective stress were determined, and the influence of the grain size of the reservoir rock matrix on the character of the change in the sandstone permeability coefficient was also established. During the test, a decrease in permeability was observed with an increase in effective stress. It was found that as a result of gradual loading/unloading of the sandstone sample, the original permeability values were not restored, which indicates the beginning of the formation of residual strains in the rock. This effect should be taken into account when modeling field development because in the process of reserves extraction the effective stress acting on the reservoir rock skeleton changes, which results in a significant chang in rock permeability. The results of laboratory studies showed that the deviation of permeability in medium-grained sandstones relative to the initial value was greater than in medium- and fine-grained sandstones. The pressure sensitivity coefficient and constant of material, which are used in empirical relationships between permeability and effective stress, were numerically estimated. At the same time, the constant of material showed no such convergence, which indicates that the values of this parameter are individual for each rock.
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Date submitted2021-07-13
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Date accepted2021-10-18
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Date published2021-12-16
Prediction of the stress state of the shotcreting support under repeated seismic load
- Authors:
- Maksim A. Karasev
- Roman O. Sotnikov
The article assesses the impact of repeated blasts on the stress-strain state of the shotcreting support, which negatively affects the bearing capacity of the support and can lead to the formation of local rock falls in places of significant degradation of the shotcreting strength. Despite the fact that a single seismic load usually does not have a significant impact on the technical condition of the shotcreting support, repeated dynamic loading can lead to the development of negative processes and affect the safety. The article considers unreinforced and dispersed-reinforced shotcreting concrete as a shotcreting support. Models of deformation of rock and shotcreting support have been studied. To describe the deformation model of a rock mass, an elastic–plastic model based on the Hook-Brown plasticity condition has been accepted, which accurately describes the elastic-plastic behavior of a fractured medium. When performing the prediction of the stress-strain state of the shotcreting support, a model of plastic deformation of concrete with the accumulation of Concrete Damage Plasticity (CDP) was adopted, which allows to comprehensively consider the process of concrete deformation both under conditions of uniaxial compression and stress, and with minor edging draft. At the first calculation stage, a forecast of the seismic waves propagation in the immediate vicinity of the explosive initiation site was made. At the second stage, forecasts of the seismic waves propagation to the mine working and the stress-strain state of the support were made. On the basis of the performed studies, a methodology for assessing the impact of repeated blasts on the stress-strain state of the shotcreting support of the mine working is proposed.
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Date submitted2020-12-02
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Date accepted2021-04-21
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Date published2021-06-24
Modeling the processes of deformation and destruction of the rock sample during its extraction from great depths
Article investigates the change in the geophysical properties of rocks in the process of extracting the rock sample from great depths. Evaluation of changes in effective elastic properties, porosity and permeability of rock samples during extraction was carried out by means of finite element modeling. Assessment of the critical dimensions and orientation of internal defects, leading to the destruction of the rock samples during extraction from great depths, has been made based on the methods of linear destruction mechanics. Approach that makes it possible to calculate the change in the mechanical properties, porosity and fracturing of reservoir rocks in the process of extracting the rock sample from depths to the surface is proposed. Use of refined data on the mechanical properties of recoverable rock samples makes it possible to increase the accuracy of digital geological models required for geological exploration, determination of reservoir properties and oil and gas saturation of a field, and development of oil and gas deposits. Application of such models is especially relevant at all stages of the fields development with hard-to-recover reserves.
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Date submitted2020-07-02
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Date accepted2021-02-16
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Date published2021-04-26
Development of viscoelastic systems and technologies for isolating water-bearing horizons with abnormal formation pressures during oil and gas wells drilling
Article provides a brief overview of the complications arising during the construction of oil and gas wells in conditions of abnormally high and abnormally low formation pressures. Technological properties of the solutions used to eliminate emergency situations when drilling wells in the intervals of catastrophic absorption and influx of formation fluid have been investigated. A technology for isolating water influx in intervals of excess formation pressure has been developed. The technology is based on the use of a special device that provides control of the hydrodynamic pressure in the annular space of the well. An experiment was carried out to determine the injection time of a viscoelastic system depending on its rheology, rock properties and technological parameters of the isolation process. A mathematical model based on the use of a special device is presented. The model allows determining the penetration depth of a viscoelastic system to block water-bearing horizons to prevent interformation crossflows and water breakthrough into production wells.
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Date submitted2020-06-15
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Date accepted2020-06-15
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Date published2020-06-30
Non-destructive testing of multilayer medium by the method of velocity of elastic waves hodograph
- Authors:
- Aleksandr I. Potapov
- Artem V. Kondratev
The method of velocity of elastic waves hodograph, aimed at non-destructive testing of structurally heterogeneous composite materials and products based on them, as well as multilayer products and constructions, is considered. The theoretical basis for determining the propagation velocity of elastic waves in a multilayer medium by the hodograph method is given. Based on the studies, recommendations are given for determining the propagation velocity of elastic waves in each individual layer of a multilayer medium, which allows non-destructive testing of the physicomechanical characteristics of each layer of a multilayer medium. It is shown that in addition to simple multiple reflections in a homogeneous medium, in a multilayer medium with parallel interfaces consisting of two or more layers, complex types of multiple reflected waves and mixed waves (reflected-refracted and refracted-reflected) can arise. The main task of applying the low-frequency ultrasonic method is to determine the acoustic parameters of the propagation of elastic waves (velocities, amplitudes, spectra). The main methods for determining the elastic wave velocities are considered, based on the hodograph equation of the indicated reflected waves in a multilayer medium.
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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 submitted2018-11-18
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Date accepted2019-01-17
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Date published2019-04-23
Calculation of elastoviscoplastic displacement of well walls in transversal and isotropic rocks
- Authors:
- A. G. Gubaidullin
- A. I. Moguchev
The relevance of the work is justified by the need to improve the technical and economic indicators of well construction based on forecasting and preventing drilling tools sticking due to the narrowing of an open well bore in the intervals of transversely isotropic rocks. A mathematical model of elastic-viscous-plastic displacement of the walls of inclined and horizontal wells has been developed during the narrowing of the open borehole due to rock creep in the intervals of transversely isotropic rocks. In the program developed based on this mathematical model, the calculation of the elastic-viscous-plastic displacement of the walls of an obliquely directed and horizontal well in the reservoir of argillite from the Western Siberia deposit was carried out. As a result of the calculation, it was established that after opening the rock with bits, the cross-section of the open borehole due to the rock creep eventually takes the form of an ellipse, the small axis of which is in the plane of the upper wall of the well and decreases with time.
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Date submitted2018-05-22
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Date accepted2018-07-04
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Date published2018-10-24
Multivariance of a velocity model for structural plotting based on seismic and borehole data
- Authors:
- A. P. Sysoev
The paper discusses the peculiarities of structural modelling (forecast of the depths of the reflecting horizons) based on the seismic and drilling data system. Seismic data are represented by vertical time values and the stacking velocity of borehole data that are the depth marks of the reflecting horizons. Vertical time and the depth of the reflecting horizons are bound by the equation of average velocity but the average velocity is not determined in a seismic experiment, therefore an issue of choosing a velocity model of a complex natural object arises. The task of structural modelling is solved by the selection of formal expressions containing correlations between the parameters of the underlying model and kinematic parameters of the wave field. The optimal decision on model selection is determined by the minimum discrepancy between the predicted and actual values of the depth of the sample boreholes. A practical example shows possible variants of the interpretation model. An inverse kinematic problem on converting the vertical time of the reflected waves at the depth of horizons is solved in each production report on the results of seismic work and is probably the most common objective of seismic exploration. Considering the variety of research objects and the apparent obviousness of the solution, this topic is underrepresented in scientific literature.
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Date submitted2016-09-16
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Date accepted2016-11-12
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Date published2017-02-22
Possibilities of seismic exploration for crystalline basement study
- Authors:
- A. N. Telegin
Possibilities of seismic methods of reflected and refracted waves have been examined for the purposes of detailed study on crystalline basement structure. Investigation of depth and structure of the basement plays an important role in the exploration of various deposits. Sedimentary cover is usually associated with oil and gas reserves. Ore deposits are formed in the basement rocks, basement splits and structure of its surface have a genetic relation not only to ore minerals, but also to oil resources. Reflection seismology is one of the main seismic methods of investigating structural geometry of the sedimentation mass, forecasting its material composition and possible hydrocarbon reserves. However, its possibilities for investigating crystalline basement are limited. Basing on many years’ experience of reflection seismology and physical modeling it has been identified that actual roughness of basement surface limits the obtainable amount of waves reflected from it. Possibilities of reflection seismology for basement structure study are mostly related to investigation of discontinuous faults as diffraction objects using diffracted waves. Method of refracted waves combined with modern procedures and material processing aimed at getting dynamic seismic sections holds much significance for the basement study, especially in the process of surface mapping and, to a lesser extent, in investigating discontinuous faults.
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Date submitted2015-10-24
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Date accepted2015-12-17
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Date published2016-08-22
Spatial distribution of energy release during propagation of fast electron beam in the air
- Authors:
- V. S. Sukhomlinov
- A. S. Mustafaev
The paper focuses on development of the analytical theory to assess spatial distribution of energy released during propagation of the fast electron beam in a gas, in particular in the air at electron energies of 1-100 keV. An approach adopted by authors [2, 3] to study inelastic deceleration of electrons in the air is further developed here. As the inelastic interaction in most cases leads to energy relaxation while elastic interaction causes distribution isotropization over directions, the first task solved in the paper is finding the electron distribution function including only elastic collisions. In the final part of this paper an analytical solution to this task is presented with account of both types of electron deceleration in the air. The calculations show that when elastic collisions are taken into account this leads to increased spatial density of energy release and to narrowing of the primary energy release region of the fast electrons, as compared to calculations accounting for only inelastic deceleration.
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Date submitted2014-12-25
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Date accepted2015-02-07
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Date published2015-12-25
Nondestructive control of elasticity modulus anisotropy of composite materials in the products
- Authors:
- A. I. Potapov
The technique of nondestructive control of anisotropy of composite materials in a product us-ing a pulse ultrasonic method is considered in the article. Calculated dependence to determine the degree of filler orientation in a polymeric composite material with varying filler laying is shown. The following filler laying is considered: chaotic, longitudinally cross, unidirectional. In addition, experimental results of anisotropy control of the elastic modulus in glass-reinforced plastics with different degrees of anisotropy using the pulsed ultrasonic method are given in the article.
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Date submitted2014-12-10
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Date accepted2015-02-20
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Date published2015-12-25
Opencast mine parameters sensitivity analysis at preliminary study of a mining project
- Authors:
- S. I. Fomin
- E. I. Bazarova
The article describes sensitivity analysis, aimed at variables dependence detection: to what extent open cast mine ultimate efficiency or performance will be affected when one of the key input variables is changed. The stronger the dependence effect, the higher the project implementation risk. The sensitivity analysis objective is demonstrated – principle factors identification – critical variables, capable of having a serious influence on the project implementation results, and impact verification of progressive (single) factorial changes. Sensitivity analysis in its content is a single-factor analysis. Output, as a basic performance indicator of an open cast mine, characterizes mine development intensity and is determined by mining-engineering and economic factors. It is proved that the impact degree from various parameters on the open cast mine output is characterized by elasticity ratio. The project indicators sensitivity analysis, which was carried out, allowed to establish the impact degree that various parameters have on the open cast mine output, which takes place in a high-angle ore deposit, characterized by elasticity ratio.
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Date submitted2010-07-23
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Date accepted2010-09-28
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Date published2011-03-21
Sistaining mining in whole different rigidity
- Authors:
- L. K. Gorshkov
- S. G. Kokoev
Studies conducted in the mines «Rostovugol», showed that, for assessing the sustainability of preparatory excavations in the management of sewage treatment works is enough to determine the allowable values of convergence of the roof and ground-level workings and potential energy of elastic deformation of the pillars. These indicators can be used in the coal mines of other basins.
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Date submitted2010-07-11
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Date accepted2010-09-14
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Date published2011-03-21
Application of seismic reflection method for engineering-geological issues solving in Saint Petersburg and Leningrad region
- Authors:
- A. S. Yakovlev
Several examples of seismic reflection method test surveys in St.-Petersburg and its suburbs are reviewed. The key point of research was the choice of an optimum field seismic works technique, processing and interpretation technique, providing the reliable solution of shallow depth investigation for the presented area.
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Date submitted2010-07-14
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Date accepted2010-09-29
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Date published2011-03-21
Basic requirements for shallow seismic field works technique by the reflected waves method for engineering-geological issues solving
- Authors:
- A. N. Telegin
- A. S. Yakovlev
The main requirements for the shallow seismic field works technique parameters for engineer-geological issues solving are represented. The optimum technique for the St.-Petersburg and its suburbs territory based on the results of experimental seismic studies, providing a detailed study of the upper part of the geological section, are proved.
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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 submitted2009-09-06
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Date accepted2009-11-14
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Date published2010-06-25
The estimation of mass velocities in a layered roof and dividing pillars of the mining system in the time of influence of shock stress waves
- Authors:
- V. V. Karpenko
- G. A. Kolton
The mass velocity diagrams transformation in the layered border zone of the mining system in the time of tension explosion waves influence is considered. The explosion wave front is suggested to be parallel to the proximate handing roof environs discontinuity. Under the admitted assumption the mass velocity epures transformation is investigated in the layered roof stone of the mining system and in the dividing pillar.
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Date submitted2009-09-07
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Date accepted2009-11-17
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Date published2010-06-25
The transformation of zone of potentially dangerous accumulative wrecks in a layeked mining roof when combined effect of the rock pressure and shock stress waves
- Authors:
- V. V. Karpenko
The transformation of potentially dangerous zone of wrecks accumulation in the layeredroof of the mining system is considered, in the time of combined action of geostatic pressure and tension shok wave. The explosion wave front is suggested to be parallel to the proximate handing roof environs discontinuity. Under this condition in the article is considered the influence of levels of critical stress and the depth of opening location on the change of implicitly dangerous zone of faults accumulation in the layers of the root stone.
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Date submitted2009-08-23
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Date accepted2009-10-17
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Date published2010-02-01
Mathematical description of microwave contact level controller for liquid agent
- Authors:
- N. V. Teterin
- O. M. Bolshunova
It is shown the problem of measurement of level in oil tanks. Considered the use of a method of the sway electromagnetic radiation for the control of level of section of environments in tanks, made its mathematical description, resulted the estimation of results of practical application.
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Date submitted2009-07-10
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Date accepted2009-09-03
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Date published2010-04-22
Lateral earth pressure in rock mass
- Authors:
- A. G. Olovyanny
The stress state of rock mass is determined by weight of overburden and the lateral earth pressure. It was stated that the stress state of rock mass has been originated with contribution of the lateral earth pressure in which the important role play the viscoelastic properties of rocks was obtained, which gives more precise assessments of stress state in rock mass than the determined ones with account of only elastic behavior.