-
Date submitted2019-10-30
-
Date accepted2019-11-23
-
Date published2020-02-25
Methodology for determining the parameters of drilling mode for directional straight sections of well using screw downhole motors
- Authors:
- Vladimir S. Litvinenko
- M. V. Dvoinikov
Article presents results of study on possibility of increasing the efficiency of drilling directional straight sections of wells using screw downhole motors (SDM) with a combined method of drilling with rotation of drilling string (DS). Goal is to ensure steady-state operation of SDM with simultaneous rotation of DS by reducing the amplitude of oscillations with adjusting the parameters of drilling mode on the basis of mathematical modeling for SDM – DS system. Results of experimental study on determination of extrema distribution of lateral and axial oscillations of SDM frame depending on geometrical parameters of gerotor mechanism and modes ensuring stable operation are presented. Approaches to development of a mathematical model and methodology are conceptually outlined that allow determining the range of self-oscillations for SDM – DS system and boundaries of rotational and translational wave perturbations for a heterogeneous rod with an installed SDM at drilling directional straight sections of well. This mathematical model of SDM – DS system's dynamics makes it possible to predict optimal parameters of directional drilling mode that ensure stable operation of borehole assembly.
-
Date submitted2019-05-30
-
Date accepted2019-09-03
-
Date published2020-02-25
Study on influence of two-phase filtration transformation on formation of zones of undeveloped oil reserves
- Authors:
- S. I. Grachev
- V. A. Korotenko
- N. P. Kushakova
In order to study the process of fluid filtration during flooding of an oil field, article uses Rapoport – Lis model of non-piston oil displacement by water. During plane-radial filtration in a homogeneous formation, radii of disturbance zones are determined with and without taking into account the end effect. Influence of changes in value of capillary pressure gradient on distribution of water saturation coefficient in the non-piston displacement zone for high and low permeability reservoirs is revealed. Application of an element model for a five-point injection and production well placement system showed that, using traditional flooding technology, flat-radial fluid filtration is transformed into rectilinear-parallel. At solving equation of water saturation, Barenblatt method of integral relations was used, which allows determining the transformation time. By solving the saturation equation for rectilinear-parallel filtration, change in the value of water saturation coefficient at bottomhole of production well for an unlimited and closed deposit is determined. It is shown that an increase in water cut coefficient of a production well is possible only for a closed formation. To determine coefficient of water saturation in a closed deposit, a differential equation with variable coefficients is obtained, an iterative solution method is proposed. In the element of the five-point system, oil-saturated zones not covered by development were identified. For channels of low filtration resistance, conditions for their location in horizontal and vertical planes are established. It is shown that, at maintaining formation pressure, there is an isobar line in formation, corresponding to initial formation pressure, location of which determines direction of fluid crossflow rates. Intensity of crossflows affects application efficiency of hydrodynamic, physical and chemical, thermal and other methods of enhanced oil recovery.
-
Date submitted2019-01-31
-
Date accepted2022-12-02
-
Date published2020-02-25
The relationship of fracture toughness coefficients and geophysical characteristics of rocks of hydrocarbon deposits
This paper contains the results of laboratory tests to determine the fracture toughness coefficient K IC of rocks for terrigenous and carbonate objects by three methods. The tests were carried out by different methods due to the lack of a standard method for determining the fracture toughness characteristics of rocks in Russia. We used the following methods for determining the K IC coefficient: the extension of core specimens with an annular fracture, the action of a concentrated load on a beam specimen with a fracture and the method of bending semi-circular samples with a fracture according to ISRM recommendations. The paper presents the relationship of the fracture toughness coefficients with the P-wave velocity and porosity. The obtained dependencies characterize the general trend of changing for the studied parameter and can be used in the design of hydraulic fracturing in the fields for which tests were conducted.
-
Date submitted2019-08-08
-
Date accepted2019-09-16
-
Date published2020-02-25
Testing of preformed particles polymer gel technology on core filtration models to limit water inflows
In order to reduce watering of wells and equalize their injectivity profiles, the prospects of introducing PPG technology in Russian fields are considered, in which preformed particles polymer gel are pumped into the injection well. These particles, being a supersorbent based on polyacrylamide, absorb water, become elastic, which allows them to shrink and tear in narrow filtration channels. When the polymer is filtered along permeable layers saturated with water, polymer particles accumulate in waterlogged intervals and thus they form a polymer plug, which redistributes the filtration flows and increases the coverage of the formation by the process of oil displacement. More than 4000 downhole operations have been carried out in the fields of China and the USA using PPG technology by now. In domestic fields in Western Siberia, there is limited experience in applying a similar technology in high-temperature formations with low mineralization of formation water. Due to the absence of hydrolytic processes in polyacrylamide, well-known domestic compositions are not applicable due to the low absorption capacity in the conditions of low-temperature deposits with increased mineralization of formation water. The authors synthesized a polymer based on polyacrylamide by block polymerization, which allows to obtain a high absorption capacity, including for low-temperature formations with high mineralization of formation water, which is typical for Perm Territory fields. Filtration experiments were carried out on core models with the composition developed by the authors, this composition focused on low formation temperatures and high mineralization of formation water. As a result of the experiments, it was found that the swollen particles of the gel are able to pass into fractures with a diameter less than their own size at least 20 times. With a significant increase in the viscosity of the dispersion medium, the stability of the suspension increases. Particles of polymer gel have the necessary strength for injection in the field conditions. The fracture permeability during polymer injection decreases by several times and becomes comparable with the permeability of pore collectors.
-
Date submitted2019-04-03
-
Date accepted2022-12-02
-
Date published2020-02-25
Influence of parameters of delayed asphalt coking process on yield and quality of liquid and solid-phase products
Paper studies the effect of excess pressure during delayed coking of asphalt, obtained by propane deasphaltization of tar, on yield and physical and chemical properties of hydrocarbon fuels' components and solid-phase product – petroleum coke. Asphalt was coked at a temperature of 500 °C and excess pressure of 0.15-0.35 MPa in a laboratory unit for delayed coking of periodic action. Physical and chemical properties of raw materials and components of light (gasoline), medium (light gasoil), and heavy (heavy gasoil) distillates obtained during experimental study were determined: density, viscosity, coking ability, sulfur content, iodine number, pour points, flash points, fluidity loss and fractional composition. Quantitative group hydrocarbon and microelement compositions and properties of obtained samples of petroleum coke (humidity, ash content, volatiles' yield, sulfur content, etc.) were also studied. Comparative assessment of their quality is given in accordance with requirements of GOST 22898-78 “Low-sulfur petroleum coke. Specifications”. In addition, patterns of changes in excess coking pressure on yield and quality indicators of distillate products and petroleum coke were revealed. With an increase in excess pressure of coking process from 0.15 to 0.35 MPa, content of paraffin-naphthenic hydrocarbons in light and heavy gasoils of delayed coking decreases. Common pattern in asphalt coking is an increase in yield of coke and hydrocarbon gas with an increase in excess pressure from 0.15 to 0.35 MPa.
-
Date submitted2020-01-09
-
Date accepted2020-01-20
-
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.
-
Date submitted2019-05-30
-
Date accepted2019-09-04
-
Date published2020-02-25
Prospects for industrial methane production in the mine n.a. V.M.Bazhanov using vertical surface wells
The estimated methane resources in the coal stratum of Donbass are 798.5 billion m 3 , including 119.5 billion m 3 in the Donetsk-Makeevsky area. Such significant potential implies that methane can be used not only for industrial production and energy purposes but also as a commodity for the chemical industry. However, in practice, commercial production of methane from coal seams, as is done in the fields of the USA, Canada, India, and China, is not carried out, and methane, obtained as a by-product, is utilized for ensuring the safety of the main technological processes for coal mining. The main reasons for this are the difficult mining and geological conditions of bedding, low thickness and permeability, which does not allow to separate methane production into an independent type of activity due to its low profitability, especially with the use of new technologies based on hydraulic fracturing of coal seams. The assessment of the possibility of industrial methane production in the mine n.a. V.M.Bazhanov in the Donetsk-Makeevsky area of Donbass, which reserves equal to 23.7 billion m 3 , showed that a significant part of the methane reserves is concentrated in coal seams and interlayers with a gas content of 18.5-20.7 m 3 /m 3 . Moreover, in the host rocks, methane is practically in a liberated state. This circumstance makes possible the commercial production of methane for its utilization from the unloaded rock mass by wells drilled from the surface, without the use of hydraulic fracturing technology. The paper discusses the technology of methane extraction by a degassing well drilled from the surface into a coal-bearing stratum unloaded from rock pressure in a mining field of the 4th eastern face of the m 3 seam of the mine n.a. V.M.Bazhanov and its subsequent use as the fuel of an electric generator. It is shown that over the entire period of operation of the pilot well, the volume of actually produced methane exceeded the design value by 23 %, and the cost of the gas produced amounted to 1535 rubles per 1000 m 3 , which is more than 3 times lower than the market price for natural gas for consumers in the Russian Federation. This made it possible to make a conclusion about the possibility of industrial extraction of mine methane using vertical surface wells for its subsequent utilization in power plants, which does not imply the usage of hydraulic fracturing technology.
-
Date submitted2019-07-21
-
Date accepted2019-09-20
-
Date published2020-02-25
Assessment of operational reliability of quarry excavator-dump truck complexes
- Authors:
- V. M. Kurganov
- M. V. Gryaznov
- S. V. Kolobanov
The method proposed in the article is based on the mathematical apparatus for quantitative assessment of the reliability of majority schemes of structural redundancy of transport processes, which provide the availability and usage of several backup delivery channels in the transport process in case of any malfunction. The principle of multi-channel haulage is commonly used in quarries for transportation of overburden and minerals from benches by dump trucks, when excavators and dump trucks performing cyclic operations function as a single excavator-dump truck complex. This pattern of work significantly increases the likelihood of fulfilling the daily plan for transporting rock mass due to the redistribution of dump trucks between mining and overburden excavators in the event of failure of one or more units of mining and handling equipment. The reliability of excavator-dump truck complexes is assessed in three stages: initial data collection for mathematical modeling of excavator-dump truck complex performance; solving the problem of optimizing the distribution of dump trucks between excavators, ensuring maximum productivity of the excavator-dump truck complex; assessment of the reliability of its work depending on the probability of fulfilling the daily plan for the transportation of rock mass. The proposed method is implemented as part of a computer program and makes it possible to automate the operational management of the process of transporting rock mass in a quarry using a mobile application. The developed guidelines can be used for any quarries with automobile transport, regardless of the type of mineral extracted, the mining method, the loading pattern, the capacity of the excavation and loading equipment fleet, and the capacity of operated dump trucks.
-
Date submitted2020-01-09
-
Date accepted2020-01-17
-
Date published2020-02-25
Methodology for Calculating the Stability of the Polymer Operating String in Permafrost
- Authors:
- V. A. Stetukha
- I. I. Zheleznyak
The goal of this paper is to develop a methodology for calculating the stability of an annular cross-section string casing made of polymer material used for the development of mineral deposits by underground leaching in permafrost formations. The aim was to determine the geometric parameters of the casing and to ensure its operational reliability. The relevance of the research is associated with the peculiarities of external influences on the string, for example, a geotechnological well operating in permafrost formation under conditions of additional exposure to ice pressure during freezing of water in the borehole annulus. This effect is usually accompanied by deformation of the casing due to ice pressure, which can lead to string collapse, abnormal operation and the risk of contamination of the geological environment. The proposed calculation method for a polymer casing is based on simulation of objects using the finite element method. We used the spatial finite elements to model the interaction of key elements of the geotechnological natural-technogenic complex: a polymer casing, ice in the annulus space and homogeneous or heterogeneous rock masses adjacent to the well. The results of the study are presented in the form of tables and patterns of displacements, which reflect stresses and strains in the elements of the calculation scheme. The analysis of the obtained results confirms the possibility of using polymer casings of different technological purposes in various conditions of permafrost formation, including extreme ones. The results of the redistribution of pressure created by ice during the freezing of water in the borehole annulus to the rock mass and the string are evaluated. Interdependent deformations of the rock mass and operating string during freezing of water in the borehole annulus are determined. The necessity of considering the properties of the rock mass in determining the pressure on the string is established. The conditions for the collapse of the string with a different combination of its parameters are revealed.
-
Date submitted2020-01-09
-
Date accepted2020-01-26
-
Date published2020-02-25
Mining excavator working equipment load forecasting according to a fuzzy-logistic model
- Authors:
- V. S. Velikanov
Due to the fact that the loads occurring in the working equipment of mining excavators are determined by a large number of random factors that are difficult to represent by analytical formulas, for estimating and predicting loads the models must be introduced using non-standard approaches. In this study, we used the methodology of the theory of fuzzy logic and fuzzy pluralities, which allows to overcome the difficulties associated with the incompleteness and vagueness of the data in assessing and predicting the forces encountered in the working equipment of mining excavators, as well as with the qualitative nature of these data. As a result of computer simulation in the fuzzyTECH environment, data comparable with experimental studies were obtained to determine the level of loading of the main elements of the working equipment of mining excavators. Based on a representative sample, a statistical analysis of the data was performed, as a result of which the equation of linear multiple stress regression in the handle of mining excavators was obtained, which allows to make an accurate forecast of the loading of the working equipment of the excavator.
-
Date submitted2019-03-31
-
Date accepted2019-08-25
-
Date published2020-02-25
Cascade frequency converters control features
The structures of systems with high-voltage cascade frequency converters containing multi-winding transformers and low-voltage low-power converters connected in series at each output phase of the load are considered. Low-voltage blocks contain three-phase diode or active rectifiers, DC capacitor filters, single-phase stand-alone voltage inverters and block disconnecting devices in partial modes (in case of failure when part of the blocks are disconnected). The possibilities of operation of cascade converters are determined, equations for correcting tasks to units in partial modes are given, tables of correction of tasks with estimates of achievable load characteristics are proposed. The results of experiments on the model of a powerful installation with a cascade frequency converter are presented, confirming the possibility of ensuring the symmetry of the load currents when disconnecting part of the blocks and the asymmetry of the circuit.
-
Date submitted2019-05-24
-
Date accepted2019-09-08
-
Date published2020-02-25
Investigation of the influence of the length of the intermediate magnetic circuit on the characteristics of magnetic gripper for robotic complexes of the mining industry
The analysis of the existing systems of mechanical grippers of various operating principles and operating environments, in the design of which both soft and hard magnetic materials are executed. The characteristics of existing prototypes are shown and the results of our own research are presented. The article presents a study of the effect of the intermediate magnetic circuit length on the characteristics of magnetic gripper, the principle of which is based on the control of the field of a permanent magnet. The gripper based on this principle of action does not require constant energy expenditures to maintain both on and off states. The description of the magnetic gripper design and the design of the test bench is given, as well as the results of a series of experiments to determine the strength of the release of the gripper at different lengths of the magnetic circuit in the on and off states, followed by statistical processing of the data. The intervals of the ranges in which with a high degree of probability there will be a value of the gripping disengagement force for various lengths of the intermediate magnetic circuit are identified. The nature of the distribution of a random variable, which is the force of decoupling of the gripper, is determined. The dependences of the gripper decoupling force on the length of the intermediate magnetic circuit for each of the gripper states are constructed. It has been established that a decrease in the length of the intermediate magnetic circuit is the cause of a decrease in the gripping adhesion force. Plots of the dependence of the gripper decoupling force were constructed using the modes of the force values varieties to visually display the experimental results. The maximum adhesion force of magnetic pickup – 9.5 kg – was achieved with an intermediate magnetic core length of 50 mm, the minimum with a length of 25 mm – 5.6 kg.
-
Date submitted2019-03-13
-
Date accepted2019-09-19
-
Date published2020-02-25
Specifying the technical state limit value of the pump pulp without disassembling
The northern part of the territory of the Republic of Sakha (Yakutia) is rich in vast deposits of diamonds. These deposits are developed by the mining company “Almazy Anabara”, which is engaged in the extraction of diamonds at seasonal processing plants using various technological equipment. One of the key types of equipment is the pulp pump of a foreign company “KETO”. The work of pulp pumps of this company in the enrichment of diamond-containing raw materials is accompanied by intensive hydroabrasive wear of their impellers, the service life of which usually does not exceed three months. In practice, untimely replacement of a worn impeller can lead to emergency breakdowns of sealing elements and bearings, which is explained by super-permissible deflections of the shaft of pumping equipment arising from a significant unbalance of the rotor. The main cause of breakdown of slurry pumps at “Almazy Anabara” seasonal processing plants is the inability to quickly identify their ultimate technical condition, the key sign of which is the maximum wear of the impeller. The seasonal beneficiation plants of “Almazy Anabara” currently need a simple and at the same time reliable diagnostic sign of pulp pumps reaching their ultimate technical state, the identification of which can be quickly performed without disassembling and using complex equipment, which is very important when operating pumping equipment in short wash season on the Far North.
-
Date submitted2019-06-19
-
Date accepted2019-09-11
-
Date published2020-02-25
Method for estimating the spectrum density of the resistance moment on the working body of a peat milling unit
- Authors:
- K. V. Fomin
The main source of dynamic loads in the drive elements and the design of the peat milling unit is the working body. The forces of external resistance arising in the process of performing a technological operation are sharply variable, random in nature. The article proposes a model of formation of the moment of resistance on the mill when interacting with peat. The case when there are several cutting planes with the same radius at the ends of the cutting elements is considered. When developing the model, it was taken into account that the operating conditions of the knives, determined by the type of cutting (blocked, semi-blocked, etc.), their width and type in each cutting plane can vary. Factors that determine the nature of loading, such as the frequency of interaction of the cutting elements with the fallow and the randomness of the operating conditions of the unit, lead to the presentation of the loads in the form of a sequence of pulses with random parameters. Expressions are obtained for determining the spectral density of the moment of resistance on the mill at the design stage, taking into account its design, operating modes, physico-mechanical properties of peat and their probabilistic characteristics. To illustrate the application of the developed approaches, a technique is presented for determining the spectral density of the moment on the working body of deep milling machines and in their drive elements based on a linear model. An example of calculation is given, and the obtained expressions are verified on the basis of experimental data. The probabilistic characteristics of the loads on the mill serve as initial information for the dynamic analysis of the drive system and the design of the unit, its strength analysis, the selection of optimal parameters and operating modes.
-
Date submitted2019-02-01
-
Date accepted2019-09-16
-
Date published2020-02-25
Priority parameters of physical processes in a rock mass when determining the safety of radioactive waste disposal
- Authors:
- V. S. Gupalo
Consideration of geodynamic, hydrogeochemical, erosion and other quantitative characteristics describing evolutionary processes in a rock mass is carried out when choosing a geological formation for the disposal of radioactive waste. However, the role of various process parameters is not equal for safety ensuring and additional percentages of measurement accuracy are far from always being of fundamental importance. This makes it necessary to identify various types of indicators of the geological environment that determine the safety of radioactive waste disposal for their detailed study in the conditions of the burial site. An approach is proposed to determine the priority indicators of physical processes in the rock mass that determine the safety of disposal of various types of radioactive waste and require increased attention (accuracy, frequency of measurements) when determining in-situ conditions. To identify such factors, we used the sensitivity analysis method that is a system change in the limits of variable values during security modeling in order to assess their impact on the final result and determine the role of various physical processes in ensuring safety. It is shown that the safety of isolation depends on various factors when burying "natural", "short-lived", and "long-lived" groups of nuclides. The factors that greatly affect safety when disposing of radioactive waste of these types are highlighted. The list of parameters of the geological environment that characterize the priority mechanisms of localization of various types of radionuclide contamination during burial and requiring the most detailed determination in full-scale conditions is defined.
-
Date submitted2020-01-10
-
Date accepted2020-01-14
-
Date published2020-02-25
Biogeochemical assessment of soils and plants in industrial, residential and recreational areas of Saint Petersburg
Soils and plants of Saint Petersburg are under the constant technogenic stress caused by human activity in industrial, residential, and recreational landscapes of the city. To assess the transformed landscapes of various functional zones, we studied utility, housing, and park districts with a total area of over 7,000 hectares in the southern part of the city during the summer seasons of 2016-2018. Throughout the fieldwork period, 796 individual pairs of soil and plant samples were collected. A complex of consequent laboratory studies performed in an accredited laboratory allowed the characterization of key biogeochemical patterns of urban regolith specimens and herbage samples of various grasses. Chemical analyses provided information on the concentrations of polluting metals in soils and plants of different land use zones. Data interpretation and calculation of element accumulation factors revealed areas with the most unfavorable environmental conditions. We believe that a high pollution level in southern city districts has led to a significant degree of physical, chemical, and biological degradation of the soil and vegetation cover. As of today, approximately 10 % of the Technosols in the study area have completely lost the ability to biological self-revitalization, which results in ecosystem malfunction and the urgent need for land remediation.