scholarly journals Conceptual Control Method of Drilling Rig’s Torsional Vibrations Frequencies

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8403
Author(s):  
Tomasz Trawiński ◽  
Marcin Szczygieł ◽  
Bartosz Polnik ◽  
Przemysław Deja

This article focuses on the possibility of using an innovative drilling method for the implementation of underground works, especially where there is no physical possibility of using large working machines. Work on a model carried out under the INDIRES project is discussed. A design of a drilling tool equipped with the proposed technology is presented. The solution in question makes it possible to increase the efficiency of the drilling process, which is confirmed by computer simulations. Also, introductory tests of a drilling process supported by torsional vibration generated by an electromagnetic torque generator provided in the KOMAG laboratory facility show the reduction of the drilling time by almost two-fold. In our opinion, adding torsional vibration acting on the plane of a drilled wall that equals natural frequencies of the drilled material represents a promising new technology for drilling. The presented work constitutes the basis for the development of the proposed technology and allows us to conclude that the developed method will be of great interest to manufacturers of drilling machines and devices.

Author(s):  
Omid Aminfar ◽  
Amir Khajepour

Reducing vibrations in well drilling has a significant effect on improving the overall performance of the drilling process. Vibrations may affect the drilling process in different ways, i.e., reducing durability of the drillstring’s elements, reducing the rate of penetration, and deviating the drilling direction. In rotary drilling, which is used to open mine and oil wells, torsional vibration of the drillstring is an important component of the overall system’s vibration that has received less attention in the literature. In this paper, we propose a finite element model for a sample blasthole drillstring used to open mine wells to investigate its torsional vibrations. Boundary conditions and elements’ specifications are applied to this model. In the model, the interaction between the insert and the rock is represented by a set of repetitive impulses according to the insert pattern. The steady-state response of the system to the repetitive impulses is found and natural frequencies, kinetic energy, and potential energy of the drillstring are calculated. The root mean square (RMS) of the total energy can be used as the measure for reducing the torsional vibration of the system. Finally, an optimum combination of inserts on the cone’s rows was found based on minimizing the total vibratory energy of the drillstring. The optimum design can reduce the torsional vibrations of the drillstring and improve the drilling performance.


Author(s):  
Jialin Tian ◽  
Genyin Li ◽  
Liming Dai ◽  
Lin Yang ◽  
Hongzhi He ◽  
...  

Torsional stick–slip vibrations easily occur when the drill bit encounters a hard or a hard-soft staggered formation during drilling process. Moreover, serious stick–slip vibrations of the drill string is the main factor leading to low drilling efficiency or even causing the downhole tools failure. Therefore, establishing the stick–slip theoretical model, which is more consistent with the actual field conditions, is the key point for new drilling technology. Based on this, a new torsional vibration tool is proposed in this paper, then the multidegree-of-freedom torsional vibrations model and nonlinear dynamic model of the drill string are established. Combined with the actual working conditions in the drilling process, the stick–slip reduction mechanism of the drill string is studied. The research results show that the higher rotational speed of the top drive, smaller viscous damping of the drill bit, and smaller WOB (weight on bit) will prevent the stick–slip vibration to happen. Moreover, the new torsional vibration tool has excellent stick–slip reduction effect. The research results and the model established in this paper can provide important references for reducing the stick–slip vibrations of the drill string and improving the rock-breaking efficiency.


Author(s):  
Berthold Schlecht ◽  
Tobias Schulze ◽  
Jens Demtro¨der

For the simulation of service loads and of their effect on the whole turbine the wind turbine manufacturers use program systems whose particular strengths lie in the wind load simulation at the rotor, in the rotor dynamics as well as in the control-technological operation of the whole turbine. The complex dynamic behavior of the drive train, consisting of the rotor, the rotor shaft, the main gearbox, the brake, the coupling and the generator, is represented as a two-mass oscillator. This simplification, which certainly is necessary within the framework of the wind load simulation programs, is by no means sufficient for the exact description of the dynamics of the more and more complex drive trains with capacities up to 5 MW. At first, the extension to a multimass torsional vibration model seems to be useful for the exact determination of the torsional vibrations in the drive train. However, in the turbines of all manufacturers there have been found forms of damage on drive train components (high axial loads in bearings, high coupling loads, radial loads on generator bearings) that cannot be explained even on the basis of a torsional vibration analysis. Moreover, in measurements on drive trains natural frequencies in the signals occurred that can no longer be explained by the torsional vibration behavior alone. Consequently, a real multibody simulation becomes necessary, for which also radial and axial vibrations can be taken into account, in addition to torsion, since these influence the torsional vibration behavior considerably. These dependences become already clear in an analysis of natural frequencies. This is illustrated by the example of a 700-kW turbine as well as by a planetary gearing for a 3-MW turbine. Especially in the dimensioning of the off-shore turbines with several MW output power, which are being planned, the use of multibody simulation will be advantageous, since the testing of turbine prototypes of this order of magnitude under the corresponding operating conditions are surely more cost-intensive and risky than the virtual testing with well validated simulation models.


2018 ◽  
Vol 108 (01-02) ◽  
pp. 47-52
Author(s):  
M. Volz ◽  
E. Prof. Abele

Im Rahmen dieses Artikels wird ein Spanungsquerschnittmodell für den Bohrprozess mit einem zweischneidigen Wendelbohrwerkzeug vorgestellt. Das Modell ermöglicht die Simulation von Schwingungen während des Bohrprozesses mit dem Ziel, die Auswirkungen auf die Bohrungsmantelfläche, Kreisform und Spanungsquerschnittsfläche zu untersuchen. Im Rahmen einer Parameterstudie werden unterschiedliche Lateral- und Torsionsschwingungen einzeln und überlagert simuliert und die Auswirkungen auf den Spanungsquerschnitt sowie auf den Bohrprozess diskutiert.   Within the scope of this article, an undeformed chip cross-section model for a drilling process with a two-edged helical drilling tool is presented. The model allows the simulation of vibrations during the drilling process with the aim of investigating the effects on the bore surface area, circular shape and cross-section area. In a parameter study, different lateral and torsional vibrations are simulated individually and then superimposed. Further, the effects of these vibrations on the undeformed chip cross-section and consequently on the drilling process are discussed.


1962 ◽  
Vol 84 (1) ◽  
pp. 21-34 ◽  
Author(s):  
C. T. Molloy

This paper deals with the application of the method of four-pole parameters to torsional vibrations. Results are developed from fundamental principles. The four-pole parameters for the basic rotational elements are derived. These include shafts (both lumped and distributed-parameter cases), disks, dampers, and gears. The equations which must be obeyed, when these elements are connected, are presented. The application to construction of equivalent electrical circuits is given and in particular a method for constructing the equivalent circuit of distributed-parameter systems is put forth. The torsional analogs of Thevenin’s and Norton’s theorems are given for rotational sources. The fundamentals mentioned above are then applied to the following problems: (a) The effect of substituting one four-pole for another in a torsional system. (b) The effect of opening a four-pole system and inserting a new four-pole between the separated four-poles. (c) Calculation of all the torques and angular velocities in a tandem system. (d) Calculation of natural frequencies of undamped four-pole systems.


1982 ◽  
Vol 26 (03) ◽  
pp. 176-189
Author(s):  
Jong-Shyong Wu ◽  
Wen-Hsiang Chen

In the preliminary design of a propulsive shafting system, the additional (vibratory) stress due to torsional vibration is one of the important factors that must be considered in addition to the mean stress induced by the steady torque. In this paper, existing information concerning shaft design is reviewed; procedures formerly performed by slide rule, diagrams, and tabulations are formulated; and, based on the induced formulas, computer programs are developed. For an engine either two cycle or four cycle, single cylinder or multicylinder, and for a shafting system either undamped or damped (inner or outer or both inner and outer), it is required only to change the input data to obtain the desired data for various order numbers of torsional vibrations due to various firing orders of the cylinders. The output data include the natural frequencies and the corresponding mode shapes of the torsional vibrations, the amplitudes of twisting angles, and the vibratory stresses of the shafts. The reliability of the induced formulas and the developed computer programs has been confirmed by agreement between the computer output and existing information.


Author(s):  
Xiaoyu Zhong ◽  
Kaidong Chen ◽  
Zaibin Cheng ◽  
Yingjie Lu ◽  
Qiuhai Lu

Abstract Slide drilling is widely used in directional drilling because of its lower cost, but the tool-face adjustment during the drilling process is almost completed by the driller, and the automatic control has not yet been realized. The main difficulty is that the drill string system has a large amount of contact and friction with the wellbore. Moreover, it is also affected by the viscous force of the mud fluid, which brings more difficulty to achieve accurate dynamic model. Considering that the actual drilling is too costly, it is necessary to establish an indoor experimental system to simulate the response of the slide drilling tool-face, thus providing an experimental platform for the research of the control method. In this paper, the dynamic equation of the torsion process of the drill pipe is established. According to the model similarity theory, the similarity condition of parameters and scale correspondence between the experimental model and the drilling prototype are obtained, which provides the basis for selection of simulated drill pipe and mud. Then the expert PID method is used to realize the automatic tool-face control based on the laboratory experimental system. The experimental results show that the expert PID method can obtain better control effect rather than the traditional PID method, and it could be used in the actual slide drilling because of the dynamic similarity.


Author(s):  
Taher Abu Seer ◽  
Nader Vahdati ◽  
Hamad Karki ◽  
Oleg Shiryayev

Rotating equipment is susceptible to torsional vibrations whenever the RPM of the rotating equipment matches one of the torsional natural frequencies. For rotating equipment running at constant RPM, it is easy to control and mitigate the torsional vibrations, but in applications where the RPM is no longer a constant and varies widely or natural frequencies are changing: there is a need for a wide range vibration reduction device. In this paper, a translational adaptive electromagnetic tuned vibration absorber (ETVA) is described where its natural frequency is varied using electronics. The ETVA is modeled and its simulation results correlate very well with experimental results. Later, this concept is used to develop a torsional tuned vibration absorber (TTVA) device. The electromagnetic TTVA can be attached to rotating equipment to control torsional vibrations. The electromagnetic TTVA adapts itself and controls the torsional vibrations as and when the RPM varies. Here in this paper, the rotating equipment and the electromagnetic TTVA are modeled. Analysis results indicate that the torsional vibration of rotating equipment can be easily controlled using this newly developed electromagnetic TTVA.


Author(s):  
Tomasz Trawiński ◽  
Marcin Szczygieł ◽  
Arkadiusz Tomas

During a serious underground incident the most important things are the lives of miners and the time necessary for the rescue team to find victims of the accident. The paper presents the concept of a new drilling system that uses torsional vibrations in the drilling process. In the article formulating mathematical models of a drilling rig is one of the tasks of the INDIRES (INformation Driven Incident RESponse) project implemented as a part of the European Research Fund for Coal and Steel. The INDIRES project is dedicated to the task of conducting a rescue operation after accidents in mines.


2010 ◽  
Vol 7 ◽  
pp. 211-218 ◽  
Author(s):  
A.G. Khakimov

Using three natural frequencies of torsional vibrations, it is possible to define the location and size of a transverse notch on the flywheel shaft.


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