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![Scheme of the tool joint tapered thread profile according to [2]: P -thread pitch, H -height of fundamental triangle, h1 -work height, h -thread height truncated, a -crest flat width, H/2 -half height of fundamental triangle, r -root flat corner radius, α/2 -half profile angle](publication/340084354/figure/fig3/AS:871618452676609@1584821441481/Scheme-of-the-tool-joint-tapered-thread-profile-according-to-2-P-thread-pitch-H.png)
Scheme of the tool joint tapered thread profile according to [2]: P -thread pitch, H -height of fundamental triangle, h1 -work height, h -thread height truncated, a -crest flat width, H/2 -half height of fundamental triangle, r -root flat corner radius, α/2 -half profile angle
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The tapered screw joints are widely used in the formation of the drill string. They consist of two parts - a box and a pin. During the process of screwing box and a pin the contact pressure between their thread surfaces arises, the magnitude of which affects the intensity of wear on these surfaces. For the first time, the authors offer in this work...
Context in source publication
Context 1
... paper [3] presents theoretical and virtual experimental studies aimed at obtaining the dependence of the velocity of the washing liquid moving through the screw technological duct between the thread surfaces of the pin and the box from the geometric parameters of this duct-its height and width. In figure 5 for clarity the cross section of this duct is painted black. Actually it is a gap between the pin and the box thread surfaces and its parameters are: a -crest flat width and (h 1 -h) -the difference between the work height and the thread height truncated of the thread profile. ...
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Contacts and joints in structures, mechanisms, and dynamic systems often exhibit high localized interface shear at their edges, leading to edge microslip and fretting wear and fatigue. This introduces complexity, nonlinearity, and multiscale friction phenomena. This paper presents a novel approach to address this issue by introducing geometrical ch...
Citations
... There are many design methods to equalize the loads in the thread and increase the fatigue strength of thread shouldered connections: stress relief grooves [1,13], modification of the thread profile [18,19], chamfers on the first turns of the thread [1, 13], variable pitch [20] and so on. The influence of technology on the quality of these connections has been studied in papers [21][22][23]. In particular, the fatigue life of the drill pipe joint can be greatly improved by introducing controllable residual compressive stress [24]. ...
Uneven distribution of stresses in the thread can cause fatigue failure of the joint, usually in the area of the first roots of the thread. This problem is very relevant for shouldered threaded joints of oil and gas equipment, which operate under conditions of significant cyclic loads. One of the ways to equalize the stresses in the thread is plastic deformation of the thread with a high load before make-up. The influence of various methods of such pre-deformation of the tool joint of drill pipes and the connection of sucker rods on the fatigue life in the thread roots of the pin and box has been studied. A method for optimizing the load for pre-deformation was proposed and it was found that the optimal load can increase the fatigue life by 5 times. The study was carried out by finite element analysis of the axisymmetric model in Abaqus/CAE and calculation of the fatigue life from the Brown-Miller dependence using fe-safe.
... The problems of stress concentration in shell systems under conditions of contact interaction while complex loading were considered in [49][50][51]. When designing such equipment, engineers pay special attention to the accuracy and tightness of threaded joints [52][53][54], increasing thread [55][56][57] and preventing self-unscrewing of threaded joints [58,59]. ...
During oil fields operation, gas is extracted along with oil. In this article it is suggested to use jet pumps for utilization of the associated oil gas, burning of which causes environmental degradation and poses a potential threat to the human body. In order to determine the possibility of simultaneous application of a sucker-rod pump, which is driven by a rocking machine, and a jet pump (ejector) in the oil well, it is necessary to estimate the distribution of pressure along the borehole from the bottomhole to the mouth for two cases: when the well is operated only be the sucker-rod pump and while additional installation of the oil-gas jet pump above its dynamic level. For this purpose, commonly known methods of Poettman-Carpenter and Baksendel were used. In addition, the equations of high-pressure and low-pressure oil-gas jet pumps were obtained for the case, when the working stream of the jet pump is a gas-oil production mixture and the injected stream is a gas from the annulus of the well. The values which are included in the resulting equations are interrelated and can only be found in a certain sequence. Therefore, a special methodology has been developed for the practical usage of these equations in order to calculate the working parameters of a jet pump based on the given independent working parameters of the oil well. Using this methodology, which was implemented in computer programs, many operating parameters were calculated both for the well and for the jet pump itself (pressures, densities of working, injected and mixed flows, flow velocities and other parameters in control sections). According to the results of calculations, graphs were built that indicate a number of regularities during the oil well operation with such a jet pump. The main result of the performed research is a recommendation list on the choice of the oil-gas jet pump location inside the selected oil well and generalization of the principles for choosing the perfect location of such ejectors for other wells. The novelty of the proposed study lays in a systematic approach to rod pump and our patented ejector pump operation in the oil and chrome plating of pump parts. The result of scientific research is a sound method of determining the rational location of the ejector in the oil well and the calculation of its geometry, which will provide a complete selection of petroleum gas released into the annulus of the oil well. To ensure reliable operation of jet and plunger pumps in oil wells, it is proposed to use reinforcement of parts (bushings, plungers, rods, etc.) by electrochemical chromium plating in a flowing electrolyte. This has significantly increased the wear resistance and corrosion resistance of the operational surfaces of these parts and, accordingly, the service life of the pumps. Such measures will contribute to oil production intensification from wells and improve the environmental condition of oil fields.
... When designing the parts to be strengthened, pay special attention to the rational choice of materials and coatings [4][5][6][7], study of temperature distribution [8,9] and stresses in layered bodies, including bodies with defects [10-12] theoretical and experimental studies of wear processes [13,14] and tests taking into account the action of corrosive environment [15][16][17]. Technological methods provide the necessary accuracy of manufacturing parts, manufacturing errors of which lead to an increase in stress levels and cause uneven operation of the cutting elements of drill bits [18,19] and rational modes of surfacing [20,21]. Operational methods involve the use of vibration protection to improve the operating conditions of the tool [22][23][24]. ...
The microstructure evolution, mechanical properties, and tribological properties of deposited metal Fe-C-Cr-Ti-B alloy by self-shielded flux-cored wire electrode (FCAW S) with the introduction of exothermic addition and without it are investigated. Experimental studies showed that the introduction of CuO Al exothermic addition in the composition of the wire core filler reduced the grain size of the deposited metal. Furthermore, X-ray diffraction analyses show that the boride layer contained FeB, Fe2B, and Ti(C, N) phases. Depth-sensing indentation was used to determine hard phase properties (hardness, Young's modulus and plasticity coefficient). It was shown that introduction of CuO –Al exothermic addition in the core filer increased the mechanical properties of deposited metal. The latter can be explained by the grain size decrease, as well as a change in the phase composition of the deposited metal due to additional copper alloying. This transformation is accompanied by an increase in hardness and in the Young's modulus. Tribological tests showed the effectiveness of introduction of the exothermic addition CuO –Al into the filler core for increasing the wear resistance under conditions of 3-body abrasive particle wear.
... Для покращення експлуатаційних властивостей бурильного інструмента застосовують низку методів. До конструкторських методів відносять удосконалення конфігурації бурильних труб [3,4], нарізних з'єднань [5][6][7], забезпечення точності нарізей [8][9][10] та запобігання самовідгвинчуванню [11], раціональний вибір матеріялів шляхом проведення корозійних досліджень і вивчення структурних змін металів [12][13][14], параметричну оптимізацію озброєння, опор і вузлів промивання доліт [15][16][17] тощо. Серед технологічних методів заслуговують на увагу раціональне армування сталевих деталей [18], оптимізація формоутворення гвинтових поверхонь та поверхонь складної топології [19,20], нанесення гнучких [21,22], металевих [23][24][25] та функціонально ´радієнтних [26][27][28] покриттів, зокрема оксидних [29], а також шліфування і лазерна обробка робочих поверхонь нарізей [30,31]. ...
Drilling workbench experimental studies are specified an empirical relation-ship between steel drilling tool oscillations and its design and drilling regime options. The standard deviation of vibration acceleration is specified as the studied oscillation option, i.e. the option workbench’s traverse after the rigidity and damping change device that is a part of drilling assembly. The rigidity and damping coefficient of this device is specified as the design options, and regime options included axial static load and speed of rotation of the steel bit. The constant factors during the experiment are the type and diameter of the steel three-cone bit and the flow rate of the flushing fluid. To obtain empirical dependences, the method of rational planning of experiments is chosen, according to which each combination of variables occurs only once during the research. The planned factor experiment is carried out using as rock sandstone blocks of the Vorotishche series composed of two layers with the stamp hardness of 1440 and 2050 MPa. The general multifactor function is presented as the product of partial dependences on four variables. As established, the probability of existence of all four partial dependences-factors is more than 0.95, which is a satisfactory result of approximation. As also found, an increase in the axial static load and speed of rotation of the steel bit leads to an increase in the vibration acceleration energy, and an in-crease in the damping coefficient—to the energy reduction. As found, the dependence of the vibration acceleration on the stiffness has a local maxi-mum, which with increasing rock hardness shifts to the range of higher stiffness values. The analysis of the obtained results allowed to provide practical recommendations for reducing the harmful effects of vibrations of the drilling tool and reducing the energy consumption of the drilling process. © 2021 G. V. Kurdyumov Institute for Metal Physics, National Academy of Sciences of Ukraine.
... In particular, a number of methods are applied to improve the performance of high-tech drilling tools. Design methods envisage drill pipe design modification [15], threaded joint improving [16][17][18], ensuring the accuracy of threads [19] and preventing their self-unscrewing [20], parametric optimization of cutters, supports and washing units of rock-destroying tools [21,22], etc. Among the technological methods are the rational reinforcement of steel parts [23], optimization of the formation of helical surfaces and surfaces of complex topology [24], and application of flexible [25,26] and functionally gradient [27][28][29][30] coatings. ...
The paper proposes a new technology for fluid production intensification, in particular hydrocarbons, which is implemented via significant increasing of the local wellbore diameter in the interval, where the productive stratum is present. The proposed technology improves the well productivity by increasing the filtration surface area and opening new channels for filtering fluids into the well. The innovative, technical idea is to drill large diameter circular recesses in planes perpendicular to the well axis. After that, the rock mass located between the circular recesses are destroyed by applying static or dynamic axial loads. The required value of the axial force is provided by the weight of the standard drilling tool. As a result of the study, the analytical relations to specify the admissible radius of circular recesses and admissible thickness of rock mass between two adjacent circular recesses from the condition of safe operation are obtained. The numerical analysis carried out for typical reservoir rocks substantiated the possibility of well diameter local reaming twenty times. A special tool for circular recess drilling is developed and the principle of its operation is described. The advantage of the proposed approaches is the low energy consumption for well diameter reaming. Our technology will have special economic expediency for the intensification of production from hydrodynamically imperfect wells and under the condition of fluid filtration according to the expressed nonlinear law.
... In addition, to ensure the tightness of the containers should pay close attention to the accuracy of the manufacture of threaded connections [14][15][16], as well as the choice of tool for threading [17][18][19]. ...
The study presented herein develops the ideas of the ecological processing technologies, in particular, the idea of plastic waste mechanical recycling and mechanical-insulating method of industrial waste utilization. The proposed ideas make possible processing of household and industrial waste into constructional products as the final products (plastic containers filled with compressed waste). The containers with the aggregate can be used for construction of roads, dams, underground and aboveground parking lots, foundations, non-residential premises, etc. The study develops an organizational and technical scheme of waste processing, prototypes of containers, and technological scheme of aggregation, presents analytical and experimental evaluation of strength of the container with the aggregate. The feature of the mechanical-insulating method of waste management is a comprehensive approach to the recycling process; as a result, almost all the recycled waste can be used for final products.
... Stress analysis on the thread teeth are shown in [24]. The influence of the profile and geometrical parameters of the tool bit cutting edge on the contact pressures and tightness of the threaded drill-string connection have been investigated in the works [25], [26]. The loading analysis on the thread teeth in cylindrical pipe thread connection are studied in paper [27]. ...
Tapered thread joints used in drill pipes largely determine the productivity of drilling processes and their environmental reliability. The quality of these joints depends on the values of the rake angle of the cutting insert of turning cutters used for making tapered threads. Modern manufacturers, because of the absents of algorithms for calculating the precision of the execution of the tapered thread spiral, depending on the size of the rake angle use the cutters only with a zero value of this angle. This greatly limits the possibility of producing drill pipes from high-strength materials, which is absolutely necessary in the modern drilling methods: obliquely directional and horizontal. The kinematic analysis presented in the article proves the difference between the theoretically specified spiral and their realized in the course of machine processing with cut tools with non-zero values of the rake angle. The deviation of the thread incline angle that is realized during turning is not regulated by standard requirement, as it is variable. The precision of the pitch of the tool-joint tapered thread is regulated by standard and must be ensured by the kinematics of the lathe. However, when screwing, the spiral screw lines of the pin and the box thread may not match, provided that they are made with using of tools with different values of the rake angle. Thus, it is lead to exceed the tolerances by one pitch. The algorithm allows to calculate the axial deviations of the screw line, depending on the value of the rake angle of the cutter for any of the points of the thread profile. It brings the fit of the cutters with a rake angle up to 5 ° to ensure the accuracy of the executed helices in the tapered thread machining.
... [4][5][6], and operational methods [7][8][9] are used to increase drilling tool reliability and durability. Besides, there have been simulated threads [10,11] and machining of contact interaction between parts of threaded connection [12,13], rock-drilling pipe [14][15][16] and downhole-drill bit contact interaction [17][18][19], well washing process [20]. The researchers have tested static load [21] and alternating load effect on fatigue [22], substantiated drilling regimes, including taking into account thermal effects in the contact zone [23,24] and effect of corrosive environments [25][26][27]. ...
... The works [10,11,30] have studied accuracy of conical threads within turning. The work [31] studied effect of machining errors on stresses of thread connection. ...
The article has grounded the necessity to develop an empirical power dependence of cutting modes influence on part surface roughness obtained during thread grinding. The calculations were carried out for grinding of parts made of steel and hard alloy. There have been developed a relation of part material properties, grinding wheel options, lubricating and cooling liquid (constant for concrete conditions of thread grinding), depth of cutting (thickness of a grinded layer per path), revolutions of a part and a wheel, longitudinal feed refer to obtained roughness. It has been stated that components of the grinding mode contribute in roughness values in different way, in particular they are arranged in the ascending order as follows: grinding depth, rotation speed, and detail’s diameter.
The total effect of technological and operational factors can lead to various types of deviations of the flank angle of the tool joint thread profile, which are uneven along the axis. It is shown that uneven deviations of the flank angle appear when tapered threading with a lathe tool with a non-zero rake angle. To analyse the effect of these deviations on the fatigue strength of the joint, a parametric axisymmetric finite element model of the ZN-80 tool joint was developed in Abaqus/CAE. In the fe-safe program, dependences of the fatigue life in the thread roots on the deviations of the flank angle of the pin thread were obtained. The box thread has not been changed. To increase the fatigue strength of the pin, in most of the cases considered, negative deviations of the flank angle of the short flank of the pin thread should be avoided, and preference should be given to positive ones. Negative relative deviations of both flanks usually worsen the fatigue strength of the pin due to the "wedge" effect. Types of deviations have been found that significantly increase fatigue strength and have an “anti-wedge” effect or equalize the load in the thread. They need detailed studies and can be the basis for optimizing the values of flank angle deviations on each turn.
Drilling oil and gas wells is always accompanied by the process of screwing and unscrewing the drill-pipe connector. Its effectiveness largely depends on the accuracy and quality of the thread profile, including the profile height’s accuracy. Studies show a decrease in the contact pressures and stresses between the threaded surfaces of the box and the pin of the drill string tool-joint as the working height of the profile increases. It is a positive factor influencing the durability and reliability of the drill pipe connector. On the other hand, the same increase of the working height leads to the improvement of the screwing process itself, which is an integral part of lowering and lifting operations during the operation of drill strings. The increased contact area allows the joint to handle high make-up torques without damaging the thread profile. It is also advisable to consider the design of the roots not of around but of an elliptical profile. To ensure leak-tightness and fatigue strength, the operation of joints with a reduced value of h should be avoided.
