Self-excited stick–slip oscillations of drill bits

Richard, Thomas; Germay, Christophe; Detournay, Emmanuel

doi:10.1016/j.crme.2004.01.016

Cited by 138 publications

(82 citation statements)

References 7 publications

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“…With those conclusions in mind, a control strategy is suggested in (Jansen and Van den Steen, 1995) that torsional vibrations the in drill-string systems should be avoided. It should be noted that Germay (Germay, 2002) and Richard et al (Richard et al, 2004) concluded that the interaction between torsional and axial dynamics of the system may cause torsional vibrations in the drilling systems. Such interaction effectively leads to the Stribeck effect, according to these authors.…”

Section: Real Drilling Systemsmentioning

confidence: 99%

Drilling Systems: Stability and Hidden Oscillations

Kiseleva

Kuznetsov

Леонов

et al. 2013

Discontinuity and Complexity in Nonlinear Physical Systems

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Esitetään Jyväskylän yliopiston informaatioteknologian tiedekunnan suostumuksella julkisesti tarkastettavaksi yliopiston Agora-rakennuksen Delta-salissa joulukuun 16. päivänä 2013 kello 12.Academic dissertation to be publicly discussed, by permission of the Faculty of Information Technology of the University of Jyväskylä, in building Agora, auditorium Delta, on December 16, 2013 at 12 o'clock noon. UNIVERSITY OF JYVÄSKYLÄ JYVÄSKYLÄ 2013Oscillations This work is devoted to the study of electromechanical models of induction motorpowered drilling systems. This is a current issue, as drilling equipment failures cause significant time and expenditure losses for drilling companies. Although there are many papers devoted to the investigation of these systems, equipment failures still occur frequently in the drilling industry. In this study, we continue investigations begun by researchers from the Eindhoven University of Technology, who introduced an experimental model of a drilling system. The model consists of two discs connected to each other by a steel string that experiences purely torsional deformation. The upper disc is connected to the driving part. The lower disc, representing the bottom end of the drill-string, experiences friction torque caused mainly by interaction with the shale. The key idea of the present study that distinguishes it from the previous model was the introduction of more complex equations of the driving part, in particular, considerations of the induction motor.Towards this end, two new mathematical models are considered. The first is a simplified one, its prototype being an electric hand drill. In this case it is assumed that the drill string is absolutely rigid and the friction torque acting on the lower part of the drill-string has asymmetric characteristics of the Coulomb type. The qualitative analysis of this model made it possible to obtain parameters on permissible loads (i.e., permissible values of the friction torque) in case the system remained in operational mode after the shale's type changes. Using computer modeling, analysis of sudden load appearance was also performed.The second mathematical model focuses on the torsional deformation of the drill during operation. For the friction torque with Coulomb type asymmetric characteristic, local analysis of the system is provided. The author carried out computer modeling of the friction model created by the researches at the University of Eindhoven. In this model, we found an interesting effect represented by hidden stick-slip oscillations.The results of the study have been published in 11 papers.

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Section: Real Drilling Systemsmentioning

confidence: 99%

Drilling Systems: Stability and Hidden Oscillations

Kiseleva

Kuznetsov

Леонов

et al. 2013

Discontinuity and Complexity in Nonlinear Physical Systems

View full text Add to dashboard Cite

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“…The exponential decaying behaviour coincides with experimental torque values and is inspired in the models given in [1], [3], [21], [24].…”

Section: A Model Describing Drillstring Torsional Behaviourmentioning

confidence: 99%

“…This model is proposed in [24] for PDC bits and considers the coupling between axial and torsional vibrations. The axial drilltring dynamics is considered through the introduction of the vertical varying force W ob affecting the bit.…”

Section: An Alternative Model For the Torque On The Bitmentioning

confidence: 99%

“…The constant µ b is the friction coefficient. In [24], W ob 0 is considered to depend on the hook-on-load.…”

Section: An Alternative Model For the Torque On The Bitmentioning

confidence: 99%

“…Section III shows an alternative model for the drillstring considering a torque-on-bit in the slipping phase which includes a harmonically-oscillating WOB. This model is proposed in [24] and will be compared with the other model presented in this paper for control purposes. Control solutions to the reduction of stick-slip conditions are given in Section IV.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Practical approach to modelling and controlling stick-slip oscillations in oilwell drillstrings

Navarro-López

Suárez

Proceedings of the 2004 IEEE International Conference on Control Applications, 2004.

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Abstract-Stick-slip friction-induced oscillations appearing in oilwell drillstrings are a source of failures which reduce penetration rates and increase drilling operation costs. For this reason, a major problem to solve is modelling the drillstring torsional behaviour and proposing control solutions to help reduce stick-slip phenomenon. This paper is focused on both problems. On the one hand, it presents dynamic drillstring models in order to reproduce stick-slip vibrations under different operating conditions. The model used for the torque on the bit is the main difference with respect to other models proposed in the literature. On the other hand, some experience-based control estrategies are evaluated in order to reduce stick-slip oscillations. These estrategies will use the angular velocity at the drillstring upper part, the torque on the bit and the weight on the bit, proved to have a key importance in the reduction of drillstring torsional vibrations. The control approach followed is a decentralized one, i.e., the angular velocity at the top end of the drillstring and the bit velocity are controlled separately. The supervisory task is made by the driller.

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Research on discrete element modeling and numerical simulation of cutting rock behavior under impact load

Zhang

Huang

et al. 2022

Energy Science & Engineering

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Combining well-drilling hammers with polycrystalline diamond compact bits to break rock under cutting load and impact load is an effective way to improve drilling efficiency. Although impact load can enhance the cutting efficiency of the cutter, excessive impact can also cause the cutter to be subjected to additional vibrations, which can decrease its working life. Knowledge of laws governing the changes in the cutting force of the cutter under impact load is essential for the design and selection of well-drilling hammers. Based on rock scratch tests and finite element rock cutting model, a discrete element modeling (DEM) rock cutting model was established to analyze the rock breaking and cutting force. Then, the material parameters of rock samples were determined, and the simulation parameters were corrected.Finally, a DEM rock cutting model under an impact load was established. The results showed that when there was an obvious difference between the average cutting force and mean peak cutting force, which corresponded to the rockbreaking transition from ductile to brittle, with introduction of the impact load leading to an earlier transition. The cutting force variance was proportional to the impact amplitude, and the increase in the cutting force variance became more obvious when the static load exceeded the critical transition weight.When the ratio of the impact amplitude to the static load was greater than 50%, the mean and variance of the cutting force increased rapidly. Under the same impact amplitude, the impact frequency had little effect on the average cutting force, but a higher frequency could significantly reduce the variance of the cutting force under a high static load (i.e., it could alleviate the fluctuation of the cutting force). These results provide a reference for the selection of welldrilling hammers and optimization of the impact load. K E Y W O R D S discrete element modeling, impact drilling, PDC bit, rock cutting force, well-drilling hammer

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Self-excited stick–slip oscillations of drill bits

Cited by 138 publications

References 7 publications

Drilling Systems: Stability and Hidden Oscillations

Drilling Systems: Stability and Hidden Oscillations

Practical approach to modelling and controlling stick-slip oscillations in oilwell drillstrings

Research on discrete element modeling and numerical simulation of cutting rock behavior under impact load

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