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Date submitted2021-01-21
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Date accepted2023-09-20
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Date published2023-12-25
Adaptation of transient well test results
Transient well tests are a tool for monitoring oil recovery processes. Research technologies implemented in pumping wells provide for a preliminary conversion of measured parameters to bottomhole pressure, which leads to errors in determining the filtration parameters. An adaptive interpretation of the results of well tests performed in pumping wells is proposed. Based on the original method of mathematical processing of a large volume of field data for the geological and geophysical conditions of developed pays in oil field, multidimensional models of well flow rates were constructed including the filtration parameters determined during the interpretation of tests. It is proposed to consider the maximum convergence of the flow rate calculated using a multidimensional model and the value obtained during well testing as a sign of reliability of the filtration parameter. It is proposed to use the analysis of the developed multidimensional models to assess the filtration conditions and determine the individual characteristics of oil flow to wells within the pays. For the Bashkirian-Serpukhovian and the Tournaisian-Famennian carbonate deposits, the influence of bottomhole pressure on the well flow rates has been established, which confirms the well-known assumption about possible deformations of carbonate reservoirs in the bottomhole areas and is a sign of physicality of the developed multidimensional models. The advantage of the proposed approach is a possibility of using it to adapt the results of any research technology and interpretation method.
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Date submitted2023-03-16
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Date accepted2023-06-20
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Date published2023-07-19
Evaluation of the influence of the hydraulic fluid temperature on power loss of the mining hydraulic excavator
In the steady state of operation, the temperature of a mining excavator hydraulic fluid is determined by the ambient temperature, hydraulic system design, and power losses. The amount of the hydraulic system power loss depends on the hydraulic fluid physical and thermodynamic properties and the degree of wear of the mining excavator hydraulic system working elements. The main causes of power losses are pressure losses in pipelines, valves and fittings, and leaks in pumps and hydraulic motors. With an increase in the temperature of hydraulic fluid, its viscosity decreases, which leads, on the one hand, to a decrease in power losses due to pressure losses in pipelines, valves and fittings, and, on the other hand, to an increase in volumetric leaks and associated power losses. To numerically determine the level of power losses occurring in the hydraulic system on an example of the Komatsu PC750-7 mining excavator when using Shell Tellus S2 V 22, 32, 46, 68 hydraulic oils with the corresponding kinematic viscosity of 22, 32, 46, 68 cSt at 40 °C, the developed calculation technique and software algorithm in the MatLab Simulink environment was used. The power loss coefficient, obtained by comparing power losses at the optimum temperature for a given hydraulic system in the conditions under consideration with the actual ones is proposed. The use of the coefficient will make it possible to reasonably select hydraulic fluids and set the values of the main pumps limit state and other hydraulic system elements, and evaluate the actual energy efficiency of the mining hydraulic excavator. Calculations have shown that the implementation of measures that ensure operation in the interval with a deviation of 10 % from the optimal temperature value for these conditions makes it possible to reduce energy losses from 3 to 12 %.
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Date submitted2021-05-13
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Date accepted2022-11-28
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Date published2022-12-29
Reproduction of reservoir pressure by machine learning methods and study of its influence on the cracks formation process in hydraulic fracturing
Hydraulic fracturing is an effective way to stimulate oil production, which is currently widely used in various conditions, including complex carbonate reservoirs. In the conditions of the considered field, hydraulic fracturing leads to a significant differentiation of technological efficiency indicators, which makes it expedient to study in detail the crack formation patterns. For all affected wells, the assessment of the resulting fractures spatial orientation was performed using the developed indirect technique, the reliability of which was confirmed by geophysical methods. In the course of the analysis, it was found that in all cases the fracture is oriented in the direction of the development system element area, which is characterized by the maximum reservoir pressure. At the same time, reservoir pressure values for all wells were determined at one point in time (at the beginning of hydraulic fracturing) using machine learning methods. The reliability of the used machine learning methods is confirmed by high convergence with the actual (historical) reservoir pressures obtained during hydrodynamic studies of wells. The obtained conclusion about the influence of the formation pressure on the patterns of fracturing should be taken into account when planning hydraulic fracturing in the considered conditions.
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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 submitted2021-09-22
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Date accepted2022-03-24
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Date published2022-04-29
Predicting dynamic formation pressure using artificial intelligence methods
Determining formation pressure in the well extraction zones is a key task in monitoring the development of hydrocarbon fields. Direct measurements of formation pressure require prolonged well shutdowns, resulting in underproduction and the possibility of technical problems with the subsequent start-up of wells. The impossibility of simultaneous shutdown of all wells of the pool makes it difficult to assess the real energy state of the deposit. This article presents research aimed at developing an indirect method for determining the formation pressure without shutting down the wells for investigation, which enables to determine its value at any time. As a mathematical basis, two artificial intelligence methods are used – multidimensional regression analysis and a neural network. The technique based on the construction of multiple regression equations shows sufficient performance, but high sensitivity to the input data. This technique enables to study the process of formation pressure establishment during different periods of deposit development. Its application is expedient in case of regular actual determinations of indicators used as input data. The technique based on the artificial neural network enables to reliably determine formation pressure even with a minimal set of input data and is implemented as a specially designed software product. The relevant task of continuing the research is to evaluate promising prognostic features of artificial intelligence methods for assessing the energy state of deposits in hydrocarbon extraction zones.
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Date submitted2019-06-28
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Date accepted2019-09-03
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Date published2019-12-24
Development of a drilling process control technique based on a comprehensive analysis of the criteria
- Authors:
- V. V. Neskoromnykh
- M. S. Popova
Compliance with drilling operations requirements is achieved by introducing advanced approaches to the management of the drilling process. Main requirement is to reduce the time and material costs for construction of the well. Increase in drilling speed is provided by rational selection of rock cutting tools and modes of its use. Development of a new generation of rock cutting tools is a complex process and requires systematic, integrated approach. In order for high costs of developing and manufacturing the tool to pay off without significantly increasing the cost of drilling, considerable attention should be paid to scientifically justified methods for its running. At well drilling using bottomhole telemetry systems with full computer support for the drilling process, there is a reasonable possibility of using a control technique based on objective results of the drilling process coming directly from the bottomhole of the well in real time. Use of a full factorial experiment is justified for processing data that affect drilling performance. Aim of the research is to develop a drilling process management technique based on a comprehensive analysis of criteria online. Objects of research: rock destruction mechanism during drilling; parameters affecting the process of well drilling; optimization of well drilling processes. The research used the following: experimental drilling with a diamond tool at the bench, method of a full factorial experiment, analytical studies. Article highlights the factors affecting the performance of a diamond rock cutting tool in the process of drilling a well, notes main criteria affecting the efficiency of the drilling process. It also describes mechanism of volumetric destruction, defines the conditions for the destruction of rock at various drilling modes and the dependence of the change in deepening per round on the parameters of the drilling modes. Technique of controlling the parameters of the drilling mode is considered, which allows determining indirectly the mode of rock destruction at the bottomhole of the well and choosing optimal values of the parameters for the drilling mode that correspond to the most favorable conditions.
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Date submitted2018-07-21
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Date accepted2018-09-03
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Date published2018-12-21
Possibilities of open eruption elimination by drilling tools
- Authors:
- P. Bujok
- M. Klempa
- M. Jakubcik
- J. Ryba
- M. Porzer
The most important raw materials for different industries are oil and natural gas. With increasing consumption, the demand for drilling and the quality of production increases. Therefore, the exploration and production of hydrocarbons requires not only first-class machinery and technological equipment, but also qualified personnel. Exploration and drilling, production of hydrocarbons, like any other industry, cannot avoid accidents, emergencies and catastrophes. The worst type of well accident is undoubtedly an open eruption of the extracted crude oil. Open eruption can lead to serious injuries to the rig personnel, damage and destruction of equipment, negative environmental impact and loss of crude oil. Exploratory drilling can cause the rise of pressure and its subsequent manifestations. During the first deep drilling, there may not be enough information about the drilled horizons. If the reservoir pressure in the production horizon is higher than the hydrostatic pressure of the fluid in the well (for example, drilling mud), the formation fluids flow into the well and move towards the surface, which causes open eruption. The rig personnel must be properly trained to be able to recognize the occurrence of rising pressure by various signs and to respond effectively to the situation. Sometimes, under the influence of the human factor or equipment failure, open eruption still occurs. The article discusses the possibilities of eliminating open eruptions with drilling tools.
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Date submitted2009-08-25
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Date accepted2009-10-23
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Date published2010-02-01
Mathematical model of impact energy pulse changes in «rock drill – rod – rock» system of rotary-percussion drill rigs
- Authors:
- S. A. Resheten
This article describes the process of passing the impact energy through the connection of drilling composition. Based on the concept of impact energy transfer, created a mathematical model of impact energy pulse changes in the «rock drill-rod-rock» system of rotary-percussion drill rigs.
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Date submitted2008-10-18
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Date accepted2008-12-24
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Date published2009-12-11
Higher efficiency in drilling of oil and gas wells under complicated conditions
- Authors:
- N. I. Nikolaev
- A. I. Ivanov
The results of researches of properties of the new native waterswelling polymer «Petrosorb» are given. Description is given to the design of plugging-up tool for liquidation of catastrophic absorption of flushing fluid in the course of drilling of oil and gas wells.