A Novel Backstepping Approach for the Attenuation of Torsional Oscillations in Drill Strings

Ullah, Farooq Kifayat; Duarte, Franklyn; Bøhn, Christian

doi:10.4028/www.scientific.net/ssp.248.85

Cited by 12 publications

(4 citation statements)

References 14 publications

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“…Thus, the properties and structure of the drill string and its elements can be considered as deterministic random with known probable characteristics or random with incomplete information about statistical characteristics. At the same time, various combinations of the listed cases are possible [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Investigation of drill string dynamics using probabilistic methods

Svitlytskyi,

Iagodovskyi,

Boshkova

2024

TAPR

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The object of research is a drill string. The work is directed to the study of the drill string dynamics and its influence on the rock, which is drilled using probabilistic methods. It is shown that the nature of the vibrations of the top of the drill string and the downhole signals are different and have a stationary random character. It is proved that the process at the output of the drill string, taking into account random disturbances, is narrow-band (quasi-harmonic) or close to it. It is found that the energy composition of the spectrum sections and the appearance of resonance peaks and their displacement is directly determined by the physical and mechanical properties of the rocks being drilled, as one of the factors that determines the vibration state of the drill string. Graphs of the spectral density of the power of pitting vibrations are given, showing their amplification at frequencies of 30–40 Hz as the hardness of the rocks being drilled increases. The maximum of the power density bending curve shifts towards low frequencies. There is a «mutual convergence» of the maxima of the power spectral density of the oscillations of the top and bottom of the drill string. It is shown that an important feature of drill string vibrations in the process of drilling with ball bits is that the intensity of vibrations of the top of the drill string passes with frequencies close to low frequencies, and the vibrations of the bottom of the string – to high frequencies. It is determined that the process at the output of the drill string, taking into account random disturbances, is narrow-band (quasi-harmonic) or close to it. As a result, the assumption of a narrow band at the output of the system, which is the basis of theoretical research, is justified. It is proven that the drill string, as a system with liquid filling under pressure, is more stable compared to a hollow structure. The washing liquid, in this case, plays the role of a dynamic absorber.

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Section: Introductionmentioning

confidence: 99%

Investigation of drill string dynamics using probabilistic methods

Svitlytskyi,

Iagodovskyi,

Boshkova

2024

TAPR

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“…The most realistic way of controlling the dynamics of the drill string is the use of drill string bottom lay outs (DSBL) with drilling mode correction devices [1,4,5].…”

Section: Introductionmentioning

confidence: 99%

Adjustment of the axial load on the bit when hole deepening by using the screw mechanism

Svitlytskyi

Sahala

2023

TAPR

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The object of the research is a screw mechanism for adjusting the axial load on the bit during a hole deepening. Mathematical modeling of dynamic processes that occur in the drill string during the hole deepening in deep wells is considered. It is shown that in the process of hole deepening, the longitudinal oscillations are proportional in their intensity to the torsional ones. Obtained boundary conditions for mathematical models of the column with the use of a shock absorber or a screw amplifier. In the course of research, it was found that the screw working mechanism of the axial load creates a relationship between the axial load on the bit and the torque on the screw. This makes it possible to install safety devices that limit the torque of the drive shaft (reciprocating engine, rotor). It is shown that various types of energy supplied to the punch, which are transformed by the punching motor and amplified due to the axial (screw) amplifier installed above the bit, ensure the rotary-progressive movement of the ball bit and increase the drilling performance. It was determined that the obtained dependencies take into account the change in time of the axial load and torque depending on the parameters of the axial amplifier and the geological and technical conditions of drilling and the arrangement of the bottom of the drill string. The research results will be useful to scientists and specialists of the oil and gas industry during the physical modeling of the processes of adjusting the axial load on the bit during a hole deepening by using a screw mechanism.

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“…Great attention is always paid to issues of drill string dynamics when drilling oil and gas wells. Therefore, the technical and economic indicators are determined, for the most part, by the efficiency of the rock-crushing toolmechanical speed and penetration on the bit [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Effect of vibration dampers on the dynamic state of a drill string

Svitlytskyi,

Iagodovskyi,

Bilenko

2023

TAPR

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The object of research is the drill string bottom structure using the correcting devices of drilling modes to control the dynamics of the drill string. The work is aimed at the study of longitudinal, torsional and transverse oscillations when adjusting the axial load on the bit by using a drilling shock absorber with a two-link characteristic. A dynamic model of the drill string during the drilling process is presented, which is a concentrated-continuous nonlinear system that interacts with the ball bit and the downhole engine as a source of energy. It is shown that elastic oscillations of all types affect the interaction of the bit with the outcrop rock. In order to evaluate drilling performance, it is necessary to take into account not only longitudinal, torsional and transverse oscillations, but also parametric oscillations, which are associated with the deformation of the weighted drill pipe under axial loads and during its rotation in the process of deepening the hole. It was found that transverse vibrations of weighted drill pipes, as a flexible element, during the drilling process are, as a rule, parametric in nature. They lead to the appearance of additional stresses in the elements of the column and, as a result, to the acceleration of their destruction and accelerated wear of the bit arms and rolling bearings. It is proved that in the future, for the development of dynamic models, it is necessary to take into account their hydrodynamics and the type, design and parameters of the applied punching elements. The obtained research results can be applied in practice in the process of designing the structure of the drill string bottom structure (DSBS) using correcting devices of drilling modes to control the dynamics of the drill string, by using a drilling shock absorber with a two-link characteristic in order to correct the axial load on the bit.

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A Novel Backstepping Approach for the Attenuation of Torsional Oscillations in Drill Strings

Cited by 12 publications

References 14 publications

Investigation of drill string dynamics using probabilistic methods

Investigation of drill string dynamics using probabilistic methods

Adjustment of the axial load on the bit when hole deepening by using the screw mechanism

Effect of vibration dampers on the dynamic state of a drill string

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