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Date submitted2024-05-11
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Date accepted2025-01-28
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Date published2025-03-21
Research and development of technology for the construction of snow airfields for accommodating wheeled aircraft in Antarctica
- Authors:
- Sergey P. Polyakov
- Sergey V. Popov
Construction of a new wintering complex at the Antarctic Vostok Station required prompt delivery of builders and mechanics to Progress Station to move them further to the work area. To solve this major logistical issue, a new landing site, later named Zenit, certified for accommodating heavy wheeled aircraft, was prepared in the Progress Station area from March to August 2022. Its snow pavement slab with a total area of 350 thousand m2 is from 100 to 120 cm high. It was made by applying snow layers with their subsequent compaction by a specially designed compaction platform for snow airfields suitable for heavy wheeled aircraft. As a result, the pavement has a surface hardness of at least 1 MPa. The layer from 30 to 60 cm has a hardness of at least 0.8 MPa, and the bottom layer at least 0.6 MPa. The first Il-76TD-90VD aircraft of the Russian company Volga-Dnepr was accommodated to the new runway on 7 November 2022. The aircraft landed in normal mode. The depth of the chassis wheels track after landing did not exceed 3 cm. The research provided in-depth understanding of the mechanisms for forming the supporting base of the runway from snow and ice in Antarctica. The experience gained can be used to solve similar issues in the Far North.
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Date submitted2024-03-20
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Date accepted2024-11-07
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Date published2025-02-27
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 submitted2023-12-15
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Date accepted2024-06-13
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Date published2025-02-25
Development of equipment and improvement of technology for inertial thickening of backfill hydraulic mixtures at the final stages of transportation
The results of the study of the functioning of the developed thickening equipment as part of the stowing complex for the formation of a flow of high-concentration hydromixture are presented. To explain the operation of the hydrotransport system of the stowing complex, equipped with a thickener of the developed design, its basic diagram is presented. A mathematical model has been created that describes the mechanism of inertial sedimentation of a solid component of a hydraulic mixture in a working chamber equipped with hydrodynamic profiles. Interaction with the profile leads to flow stratification due to a change in the trajectory of movement and a decrease in speed. The interval of rational velocity of primary pulp entering the input of the working chamber of the inertial thickener is substantiated. The synthesis of solutions of the thickening process model is performed in the COMSOL Multiphysics and Ansys Fluent programs. This made it possible to eliminate physical contradictions in the operation of the equipment and justify the overall dimensions of its main elements, ensuring the implementation of the mechanism of inertial sedimentation of the slurry. It was found that the concentration of the thickened flow at the outlet branch pipe of the thickener working chamber is determined by the level of the primary hydraulic fluid velocity, the characteristic length of the section of interaction with the deflecting profile, and the ratio of the flow and attack angles. A nomogram of the dynamics of the change in the hydraulic fluid concentration in the section of the outlet branch pipe depending on the ratios of the overall dimensions of the deflecting profile of the working chamber was compiled. The results of the study allowed formulating recommendations for selecting the dimensions of the thickener's deflecting hydrodynamic profile to form a flow of hydraulic mixture with a concentration of about 50 % by weight. The developed equipment can be used in a stowage complex and will increase the range of supply of the stowage mixture. This is due to the fact that a flow of primary slurry with a low concentration, due to lower pressure losses, can be moved in a pipeline system over a greater distance than a flow with a high filler content. The use of a thickener at the final stage of transportation is intended to increase the concentration of the hydraulic mixture immediately before production.
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Date submitted2023-06-25
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Date accepted2024-11-07
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Date published2025-02-25
Study of wormhole channel formation resulting from hydrochloric acid treatment in complex-type reservoirs using filtration and X-ray computed tomography methods
- Authors:
- Andrei A. Аbrosimov
The primary function of hydrochloric acid treatment (HAT) is to create the maximum number of high-conductivity channels in the near-wellbore zone of the reservoir to restore its permeability and enhance hydraulic connectivity between the undisturbed part of the formation and the well. The objective of this study is to physically model HAT on core samples from the Orenburg oil and gas condensate field and to research the impact of such treatment on the structure of the pore space of rocks related to complex-type reservoirs. The complexity of the rock's pore space and the low permeability of the formations are distinguishing features of the study object. For this reason, HAT is a widely applied method for production intensification, necessitating the verification of acid injection rates, where the success criterion is the formation of high-conductivity filtration channels (wormholes) in the near-wellbore zone. These channels significantly expand the drainage area of wells, thereby bringing additional reservoir sections into development. The study examined the characteristics of filtration channel development resulting from acid treatment. Their structure was characterized and analyzed using X-ray computed tomography. The complex study confirmed the accuracy of the selected injection rate and provided practical recommendations for enhancing the efficiency of HAT.
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Date submitted2024-03-29
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Date accepted2024-11-07
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Date published2025-02-26
Well killing with absorption control
The development of new fields with low-permeability reservoirs required the introduction of new production technologies, of which the most significant for well killing and underground repair were multi-ton hydraulic fracturing, the simultaneous operation of two or three development sites by one well grid, and an increase in the rate of fluid extraction. These global decisions in field development have led to the need to search for new effective materials and technologies for well killing. The article is devoted to the analysis of problems associated with the process of killing production wells in fields characterized by increased fracturing, both natural and artificial (due to hydraulic fracturing), with reduced reservoir pressure and a high gas factor. The relevance of the analysis is due to the increase in the number of development sites where complications arise when wells are killed. Particular attention is paid to technical solutions aimed at preserving the filtration and capacity properties of the bottomhole formation zone, preventing the absorption of process fluid, and blocking the manifestation of gas. The classification of block-packs used in killing is given, based on the nature of the process fluid. Suspension thickened water-salt solutions are considered, forming a waterproof crust on the surface of the rock, which prevents the penetration of water and aqueous solutions into the formation. This approach ensures the safety and efficiency of killing operations, especially when working with formations in which maintaining water saturation and preventing the ingress of the water phase are of critical importance. Modern trends in the development of technology are revealed, and promising areas for further improvement of well killing with absorption control are outlined.
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Date submitted2024-05-28
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Date accepted2024-11-07
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Date published2024-12-25
Methods of intensification of pipeline transportation of hydraulic mixtures when backfilling mined-out spaces
The paper presents an analysis of the advantages and limitations of additional measures to intensify the transportation of the backfill hydraulic mixture flow. The results of the analysis of the conditions for using pumping equipment to move flows with different rheological properties are shown. Generalizations of the methods for influencing the internal resistance of backfill hydraulic mixtures by means of mechanical activation, as well as increasing fluidity due to the use of chemical additives are given. The article presents the results of studies confirming the feasibility of using pipes with polymer lining, which has proven its efficiency in pumping flows of hydraulic mixtures with different filler concentrations. An analytical model of hydraulic mixture movement in the pipeline of the stowage complex has been developed. The trends in pressure change required to ensure the movement of hydraulic mixture in pipelines of different diameters are exponential, provided that the flow properties are constant. The effect of particle size on the motion mode of the formed heterogeneous flow, as well as on the distribution of flow density over the cross-section, characterizing the stratification and change in the rheological properties of the backfill hydraulic mixture, is assessed. An analytical model of centralized migration of the dispersed phase of the hydraulic mixture flow is formulated, describing the effect of turbulent mixing of the flow on the behavior of solid particles. An assessment of the secondary dispersion of the solid fraction of the hydraulic mixture, which causes a change in the consistency of the flow, was performed. The studies of the influence of the coefficient of consistency of the flow revealed that overgrinding of the fractions of the filler of the hydraulic mixture contributes to an increase in the required pressure in the pipeline system.
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Date submitted2024-09-09
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Date accepted2024-11-05
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Date published2024-11-12
Acoustic emission criteria for analyzing the process of rock destruction and evaluating the formation of fractured reservoirs at great depths
In order to study the mechanism of destruction of rocks of various genesis and the formation of fractured reservoirs at great depths, laboratory studies of rock samples in the loading conditions of comprehensive pressure with registration of acoustic emission (AE) and parameters of the process of changing the strength and deformation properties of samples were carried out. The spatial distributions of the hypocenters of AE events for each sample were investigated. By the nature of the distributions, the fracture geometry is described, then visually compared with the position of the formed macrofractures in the samples as a result of the tests. The time trends of the amplitude distribution b, set by the Guttenberg – Richter law, were calculated, which were compared with the loading curves and trends of the calculated AE activity. Based on the analysis of the AE process for three types of rocks – igneous (urtites), metamorphic (apatite-nepheline ores), and sedimentary (limestones) – parameterization of acoustic emission was carried out to determine the features of the deformation process and related dilatancy. As a result, three types of destruction of samples were identified, their geometry and changes in strength and seismic criteria were established.
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Date submitted2023-09-29
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Date accepted2023-10-25
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Date published2024-08-26
Laboratory studies of transformation of porosity and permeability and chemical composition of terrigenous reservoir rocks at exposure to hydrogen (using the example of the Bobrikovskii formations in the oil field in the northeast Volga-Ural oil and gas province)
The article describes the methodology for laboratory studies of reservoir rock exposure to hydrogen. The stages of sample research and the instruments used in the experiments are considered. A comparative analysis of the results of studies on porosity and permeability of core samples was performed. It was shown that after exposure to hydrogen, the porosity decreased by 4.6 %, and the permeability by 7.9 %. The analysis of correlation dependencies demonstrated a typical change in the relationship of these characteristics: after the samples exposure to hydrogen the scatter of the values increased and the correlation coefficient decreased, which indicates a change in the structure of the void space. Based on the research results, it was concluded that the decrease in porosity and permeability of the core samples occurred due to their minor compaction under the action of effective stresses. The chemical analysis of the rock showed no major difference in the composition of the basic oxides before and after exposure to hydrogen, which points to the chemical resistance of the studied formation to hydrogen. The experimental results showed that the horizon under consideration can be a storage of the hydrogen-methane mixture.
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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 submitted2021-12-15
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Date accepted2022-09-12
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Date published2023-08-28
Substantiation and selection of the design parameters of the hydroficated equipment complex for obtaining backfill mixtures from current enrichment tailings
The issue of the influence of the concentration of the solid phase on the reduction of energy costs and specific energy consumption during pulp transportation is considered. The procedure for preparing slurry from the current enrichment tailings is shown. A scheme is given and the operation of a hydroficated unit for thickening and hydraulic transport of backfill mixtures is described. A diagram of the movement of solid particles in one of the units of the complex – a lamellar thickener is shown. The summary table shows the main design parameters and characteristics of the lamellar thickener. A general view of the laboratory setup used for experimental studies with slurry at various concentrations is given. An example of calculating productivity, density and specific load is presented. The dependence of the shear stress on the velocity gradient was determined for various pulp concentrations. Experimental studies of the process of thickening the production of slurry from the current enrichment tailings have been carried out. It was found that the geometric dimensions of the thickener depend on the concentration of the solid phase in the transported mixture. It is concluded that the flow rate of the slurry and the head loss are functions of the rheological characteristics of the viscoplastic slurry and can be calculated from the derived calculated dependencies.
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Date submitted2022-05-12
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Date accepted2022-09-15
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Date published2022-12-29
Problem solution analysis on finding the velocity distribution for laminar flow of a non-linear viscous flushing fluid in the annular space of a well
- Authors:
- Vasiliy I. Nikitin
Modern drilling fluids are non-linear viscous media with an initial shear stress. In classical scientific works on hydromechanical modeling of drilling fluids motion in pipes and annular channels the Shvedov – Bingham approximation and Ostwald – de Waale power-law model were used, which did not fully account for behavior of technological fluids in a wide range of shear rates. This article presents a numerical solution for a mathematical model of drilling fluid motion of the three-parameter Herschel – Bulkley rheological model in the annular space of the well. The Herschel – Bulkley model in the rheological equation takes into account the presence of initial shear stress and a tendency for viscosity to change with shear rate, which distinguishes it from the Ostwald – de Waale and Shvedov – Bingham models. The target function in solving the equation of motion is the velocity distribution in the radial direction of the upward flow of the flushing fluid. The analysis of obtained solution is based on the theory of velocity profile influence on quality of cuttings removal during wellbore cleaning. Due to peculiarities of mathematical statement of the task, which supposes necessity of differential equation of motion solution, Wolfram Mathematica computational software has been used as a calculation tool. The analysis of numerical solution allowed to draw conclusions about the possibility of its application in evaluation of velocity profile when drilling fluid moves in annular space of the well. The possibility for application of modified excess coefficient as a relative quantitative parameter for evaluation of velocity profile uniformity was substantiated.
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Date submitted2022-03-01
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Date accepted2022-05-25
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Date published2022-12-29
Study on the rheological properties of barite-free drilling mud with high density
Improved drilling and reservoir penetration efficiency is directly related to the quality of the drilling mud used. The right choice of mud type and its components will preserve formation productivity, stability of the well walls and reduce the probability of other complications. Oil and gas operators use barite, less often siderite or hematite weighting agent as a weighting component in the composition of drilling muds for the conditions of increased pressure. But the use of these additives for the penetration of the productive formation leads to the reduction of filtration characteristics of the reservoir, as it is almost impossible to remove them from the pore channels. Therefore, barite-free drilling mud of increased density based on formic acid salts with the addition of carbonate weighting agent as an acid-soluble bridging agent is proposed. The results of experimental investigations on rheological parameters of barite-free solutions are given and the obtained data are analyzed. Based on the comparison of results it is recommended to use high-density drilling mud on the basis of formic acid salts (sodium and potassium formate) and with the addition of partially hydrolyzed polyacrylamide with molecular mass of 27 million.
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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 submitted2021-05-27
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Date accepted2022-09-06
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Date published2022-11-10
Application of resonance functions in estimating the parameters of interwell zones
It is shown that the use of force resonance leads to the effect of “shaking” the formation, followed by breaking up the film oil and involving it in the further filtration process. For the first time in oilfield geophysics, the concept of passive noise-metering method is justified for monitoring oil and gas deposit development by measuring the quality factor of the contours in the point areas of formation development channels in interwell zones. It is established that determining the depth of modulation for the reactive substitution parameter of the linear FDC chain is crucial not only for determining the parametric excitation in FDC attenuation systems, but also without attenuation in the metrological support for the analysis of petrophysical properties of rock samples from the wells. It is shown that based on the method of complex amplitudes (for formation pressure current, differential flow rates, impedance), different families of resonance curves can be plotted: displacement amplitudes (for differential flow rates on the piezocapacity of the studied formation section), velocities (amplitudes of formation pressure current) and accelerations (amplitudes of differential flow rates on the linear piezoinductivity of the FDC section). The use of predicted permeability and porosity properties of the reservoir with its continuous regulation leads to increased accuracy of isolation in each subsequent sub-cycle of new segment formation in the FDC trajectories, which contributes to a more complete development of productive hydrocarbon deposits and increases the reliability of prediction for development indicators.
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Date submitted2022-02-24
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Date accepted2022-05-25
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Date published2022-07-26
Litsa uranium ore occurrence (Arctic zone of the Fennoscandian Shield): new results of petrophysical and geochemical studies
Mineralogical, petrophysical and geochemical studies have been carried out to determine the sequence and formation conditions of uranium mineralization within the Litsa ore occurrence (Kola Region). Mineralogical studies show the following formation sequence of ore minerals: uraninite – sulfides – uranophane, coffinite, pitchblende. Two stages of uranium mineralization are distinguished: Th-U (1.85-1.75 Ga) and U (400-300 Ma). The distribution of physical properties of rocks in the area is consistent with the presence of two temporal stages in the formation of mineralization with different distribution and form of uranium occurrence in rocks. The factors that reduce rock anisotropy are the processes of migmatization and hydrothermal ore mineralization, which heal pores and cracks. Fluid inclusions in quartz studied by microthermometry and Raman spectroscopy contain gas, gas-liquid and aqueous inclusions of different salinity (1.7-18.4 wt.% NaCl-eq.). According to homogenization temperatures of inclusions in liquid phase, the temperature of the Paleoproterozoic and Paleozoic stages of uranium mineralization at the Litsa ore occurrence is ~ 300 and 200 °С, respectively. Correlations of the spatial distribution of elastic anisotropy index with an elevated radioactive background allow using this petrophysical feature as one of the prognostic criteria for uranium and complex uranium mineralization when carrying out uranium predictive work.
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Date submitted2021-09-17
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Date accepted2022-04-07
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Date published2022-12-29
Technique for calculating technological parameters of non-Newtonian liquids injection into oil well during workover
Technique for automated calculation of technological parameters for non-Newtonian liquids injection into a well during workover is presented. At the first stage the algorithm processes initial flow or viscosity curve in order to determine rheological parameters and coefficients included in equations of rheological models of non-Newtonian fluids. At the second stage, based on data from the previous stage, the program calculates well design and pump operation modes, permissible values of liquid flow rate and viscosity, to prevent possible hydraulic fracturing. Based on the results of calculations and dependencies, a decision is made on the necessity of changing the technological parameters of non-Newtonian liquid injection and/or its composition (components content, chemical base) in order to prevent the violation of the technological operation, such as unintentional formation of fractures due to hydraulic fracturing. Fracturing can lead to catastrophic absorptions and, consequently, to increased consumption of technological liquids pumped into the well during workover. Furthermore, there is an increased risk of uncontrolled gas breakthrough through highly conductive channels.
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Date submitted2021-02-28
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Date accepted2021-11-30
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Date published2021-12-27
Substantiation of analytical dependences for hydraulic calculation of high-viscosity oil transportation
- Authors:
- Alexander K. Nikolaev
- Natalia А. Zaripova
One of the development priorities in oil and gas industry is to maintain gas and oil pipeline networks and develop pipeline-connected gas and oil fields of the Arctic zone of the Russian Federation, a promising region the resource potential of which will not only meet a significant portion of internal and external demand for various types of raw materials and primary energy carriers, but will also bring great economic benefits to subsoil users and the state. The mineral and raw material centers of the Nadym-Purskiy and Pur-Tazovskskiy oil and gas bearing areas are among the most attractive regions of the Arctic zone. It is necessary to develop a scientifically substantiated approach to improve the methods of oil transportation from the field to the existing pipelines. As it is known, the task of increasing the efficiency of pipeline transportation of high-viscosity oil is inseparably connected with solving problems in the field of thermal and hydraulic calculation of pipeline system. The article presents the substantiation of dependencies for hydraulic calculation of pipelines transporting high-viscosity oil exhibiting complex rheological properties. Based on the laws of hydraulics for non-Newtonian fluids, the formulas for calculating head losses for fluids obeying Ostwald's law are proposed, their relationship to the classical equations of hydraulics is shown. The theoretical substantiation of looping installation for increasing the efficiency of pipeline transportation of high-viscosity oil taking into account the received dependences for power fluid is considered.
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Date submitted2021-07-07
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Date accepted2021-10-18
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Date published2021-12-16
Influence of hydraulic compression on porosity and permeability properties of reservoirs
Active development of hard-to-recover oil reserves causes the need for an innovative approach to methods of oil recovery and intensification of its production, based on taking into account the specifics of filtration processes in low-productive reservoirs and complex geological and physical conditions. Pilot works for studying the mechanism of changes in porosity and permeability properties of reservoirs during swabbing of wells are presented. Based on the hydrodynamic investigations performed, the results of the work are analyzed. The method of oil production intensification using hydraulic compression of formation has been developed. It has been shown that when using hydraulic compression technology in the pore space of the formation, the effect of capillary and gravitational forces is strongly reduced. The influence of these forces decreases when significant pressure gradients with changing direction are formed during well swabbing for depression impact on the bottomhole zone of the formation. Hydraulic compression induced an increase in well productivity and flow rate; insights into how how permeability and porosity properties change during well swabbing were clarified. The range of compressive durability (minimum and maximum values) was determined for the Verean deposits of the Melekeskaya Depression and the South Tatar arch. The impact of formation hydraulic compression caused changes in permeability and porosity properties of the reservoir in the bottomhole zone on a qualitative level. Piezo- and hydraulic conductivity increased by 20 %. Experimental work in well 1545 of Keremetyevskoe field showed an increase of piezo- and hydraulic conductivity coefficients, effective formation thickness, change of filtration flows character.
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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 submitted2019-12-25
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Date accepted2020-06-30
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Date published2020-10-08
Accounting of geomechanical layer properties in multi-layer oil field development
Amid the ever-increasing urgency to develop oil fields with complex mining and geological conditions and low-efficiency reservoirs, in the process of structurally complex reservoir exploitation a number of problems arise, which are associated with the impact of layer fractures on filtration processes, significant heterogeneity of the structure, variability of stress-strain states of the rock mass, etc. Hence an important task in production engineering of such fields is a comprehensive accounting of their complex geology. In order to solve such problems, the authors suggest a methodological approach, which provides for a more reliable forecast of changes in reservoir pressure when constructing a geological and hydrodynamic model of a multi-layer field. Another relevant issue in the forecasting of performance parameters is accounting of rock compressibility and its impact on absolute permeability, which is the main factor defining the law of fluid filtration in the productive layer. The paper contains analysis of complex geology of a multi-layer formation at the Alpha field, results of compression test for 178 standard core samples, obtained dependencies between compressibility factor and porosity of each layer. By means of multiple regression, dependencies between permeability and a range of parameters (porosity, density, calcite and dolomite content, compressibility) were obtained, which allowed to take into account the impact of secondary processes on the formation of absolute permeability. At the final stage, efficiency of the proposed methodological approach for construction of a geological and hydrodynamic model of an oil field was assessed. An enhancement in the quality of well-by-well adaptation of main performance parameters, as well as an improvement in predictive ability of the adjusted model, was identified.
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Date submitted2019-12-20
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Date accepted2020-09-01
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Date published2020-10-08
Features of the underground storages construction in depleted oil and gas condensate fields
The paper considers the features of the underground storages (US) construction in depleted oil and gas condensate fields (DOGCFs). The requirements for the structure of the formation, corresponding to the parameters of the object for possible US creation are presented. The influence of geological, hydrogeological, mining and technical rock formation conditions on the reliability and tightness of underground storages, including underground gas storages, has been evaluated. The necessary conditions for the US design are analyzed at the example of the Ach-Su oil and gas condensate field, in the presence of a well-explored trap with acceptable parameters for the construction of an underground storage. An important aspect is the geological conditions that meet the criteria for selecting the object: the required structure, the absence of fracturing faults, high reservoir properties of the formation, a sufficient volume of the deposit for the storage. Geological conditions lay the basis for determining the individual characteristics of the US construction technology at each DOGCF. The refined results for the current gas-saturated pore volume and the rate of pressure drop in the formation are presented, which makes it possible to select improved technological indicators in the course of operation of the created US. In order to select the optimal option for the design and construction of the US, the results of economic and geological scenarios analysis were studied concurrently with the capabilities of the technological operation of the object and transport system, which can ensure the maximum daily production of the storage.
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Date submitted2019-10-30
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Date accepted2020-02-03
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Date published2020-10-08
Concept of technology for determining the permeability and porosity properties of terrigenous reservoirs on a digital rock sample model
- Authors:
- Ivan P. Belozerov
- Marsel G. Gubaydullin
The aim of the article is to form the concept of technology for determining the permeability and porosity properties of terrigenous reservoirs using mathematical modeling methods on a digital rock sample model. Digital rock sample modeling is used to assess geological oil reserves. The article presents the concept of digital rock sample modeling technology, which allows carrying out qualitative investigations to determine the permeability and porosity characteristics of the formation, including modeling the pore space and filtration processes. The essence of the concept is that the simulation model of the microstructure for the digital model is formed on the basis of a large number of parameters obtained during lithological and petrographic investigations of thin sections, a study of the sludge and geophysical investigations of wells. The acquired model can be used as a basis for subsequent modeling of filtration processes. Conductivity of single channels of the formed model can be calculated using molecular dynamics methods, models of Boltzmann's lattice equations, and other mathematical models and methods. Based on the results of the study carried out, the application of stochastic packing methods for modeling the structure of the pore space in the digital rock sample model of terrigenous reservoirs is substantiated. In connection with the development of computer and nanotechnologies and their use in the oil and gas industry, solutions that allow obtaining adequate results of digital rock sample models are of high importance and relevance for the production sector. It is especially important to use digital rock sample models in the study of reservoir rocks of shelf fields in the western part of the Russian Arctic, oil shales, rocks represented by loose weakly cemented reservoirs, and others, which are complex for physical experiments.
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Date submitted2020-06-12
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Date accepted2020-06-12
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Date published2020-06-30
Management of hardening mixtures properties when stowing mining sites of ore deposits
Underground mining is characterized by the weakening of the bearing rock mass strata competence and the accumulation of mineral waste. The full use of subsurface resources is ensured by the use of technologies with filling voids by hardening mixtures, which requires high-quality raw materials to obtain the required strength. The deficit of the binding component can be filled with the use of granulated slags of blast-furnace process, mill tailings, ash-slags and other wastes. Most often, voids are laid by mixtures with a combination of cement and a binding component. Mixtures with ash-slag additives to cement in an equivalent amount are not inferior to the strength of the mixture only with cement, especially when grinding ash-slag. The properties of stowing rock masses when using composite binding components and inert fillers are controlled by mechanical, chemical, physical and energy effects at the stages of preparation and transportation of hardening mixtures. To obtain the active fraction of cement substitutes, disintegrators are used that apply the inertia forces of materials at a high speed of rotation with an increase in high activity indicators and lower energy costs. The components of hardening mixtures can be the majority of waste from mining and related industries, which is determined experimentally in specific conditions.
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Date submitted2019-07-09
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Date accepted2019-09-26
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Date published2020-04-24
Development of mathematical models to control the technological properties of cement slurries
Oil and gas producing enterprises are making increasingly high demands on well casing quality, including the actual process of injection and displacement of cement slurry, taking into account requirements for the annular cement level, eliminating possible hydraulic fracturing, with developing a hydraulic cementing program. It is necessary to prevent deep invasion of cement slurry filtrate into the formation to exclude bridging of productive layers. It is impossible to fulfill all these requirements at the same time without application of modifying additives; complex cement compositions are being developed and applied more often. Furthermore, need to adjust cement slurries recipes appears for almost every particular well. In order to select and justify cement slurries recipes and their prompt adjustment, taking into account requirements of well construction project, as well as geological and technical conditions for cementing casing strings, mathematical models of the main technological properties of cement slurries for cementing production casing strings in the Perm Region were developed. Analysis of the effect of polycarboxylic plasticizer (Pl) and a filtration reducer (fluid loss additive) based on hydroxyethyl cellulose (FR) on plastic viscosity (V), spreadability (S) and filtration (F) of cement slurries is conducted. Development of mathematical models is performed according to more than 90 measurements.
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Date submitted2020-01-09
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Date accepted2020-01-20
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Date published2020-02-25
Mechanical Properties of Sandstone using non-Destructive Method
- Authors:
- H. Rajaoalison
- A. Zlotkowski
- G. Rambolamanana
The understanding of physical and mechanical properties of rock is considered as critical in drilling, geo-engineering, and construction applications. As an example, the awareness of these rock parameters contributes to avoid or minimizing instability around the wellbore while drilling. The laboratory experiment of understanding of these parameters can be done in two-different ways: static, where the sample subjects to destruction after the test and dynamic, known as non-destruction method. The non-destructive method using ultrasonic waves under a series of different stress conditions, starting from 7 to 56 MPa with incrementation of 7MPa, has been used in this paper in order to characterize the mechanical properties of dry Zbylutów sandstone at 20 and 80°C. The velocity of primary (P) and secondary (S) waves within these ranges has been recorded in order to understand the behavior of the mechanical properties. The results showed that the Young’s modulus, bulk modulus, shear modulus, and Lame’s constant of Zbylutów sandstone have a positive correlation with good coefficient correlation with the increased stress, while the Poisson’s ratio showed a negative correlation. Besides, the effect of temperature on the rock parameters is approved by the decrease of primary wave velocity in this two-different temperature range. Such results are necessary when preparing the appropriate mud weight for drilling process, which is related to wellbore instability.