Nonlinear Stochastic Drill-String Vibrations

Spanos, Pol D.; Chevallier, Arnaud Michel; Politis, Nikolaos

doi:10.1115/1.1502669

Cited by 82 publications

(34 citation statements)

References 23 publications

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“…The equations of equilibrium of moments applied to the bit are as follows [9,19] vector connecting point C with the G point (Fig. 5).…”

Section: Whirling Of Ellipsoidal Bits On a Plane Uneven Bottom Of A Bmentioning

confidence: 99%

“…The backward whirling is believed to randomly happen to some degree in 40% of all wells [1]. In the majority of cases, previous studies of this dynamic process have concentrated primarily on assumption that in whirling the rotating drill bit is compressed to the bore-hole wall and is rolling on its surface [2][3][4][5][6][7][8][9][10]. But in our opinion, a prominent phase of this effect proceeds at the initial stage of its generation.…”

Section: Introductionmentioning

confidence: 99%

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Frequency Analysis of Drill Bit Whirlings on Uneven Bottoms of Deep Bore-Holes

Gulyayev¹,

Glazunov²,

Vashchilina³

2017

JMSS

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An incipient stage of a rotating drill string bit whirl motion proceeding on a well bottom surface is studied on the basis of kinematic (nonholonomic) models of mechanic interaction between the contacting uneven bodies. The bit is considered to be an absolutely rigid spherical or ellipsoidal body, the well bottom surface can be plane or spherical. It is assumed that the system coaxiality is disturbed through small initial curvature of the drill string, imperfections of the bit and bore-well geometry or the system mass debalance. Linearized equations of the bit whirling are deducted, the frequencies of periodic motions are calculated, and their modes are constructed for different geometric parameters of the spherical and ellipsoidal bits. It is demonstrated that, depending on the system properties, the bit motion can acquire the regimes of forward and backward whirlings or to transit to the state of stationary spinning relative to an immovable center of velocities. The most unfavorable and atypical whirling modes are characteristic for oblate ellipsoidal bits and curvilinear surfaces of the well bottom.

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“…The equations of equilibrium of moments applied to the bit are as follows [9,19] vector connecting point C with the G point (Fig. 5).…”

Section: Whirling Of Ellipsoidal Bits On a Plane Uneven Bottom Of A Bmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Frequency Analysis of Drill Bit Whirlings on Uneven Bottoms of Deep Bore-Holes

Gulyayev¹,

Glazunov²,

Vashchilina³

2017

JMSS

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show abstract

“…More recently, nonlinear and time-domain modeling solutions have become possible (Spanos et al 2002). This is critical to achieve the required level of accuracy to make meaningful contributions to drilling system behavioral prediction.…”

Section: Introductionmentioning

confidence: 99%

Modeling of BHA dynamic behaviors

Santos

Priimenko

Sugiura

2013

J Petrol Explor Prod Technol

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“…Depending on their values, the analysis results have shown that the system can be stable or undergo forward or backward whirl. Spanos et al [21] and Ritto et al [22] underline that the uncertainty is inherent in the properties of parameters determining the drilling processes, therefore, the stochastic nature of the bit rock interaction should be taken into consideration. General questions of friction influence on deep hole drilling processes are outlined by R. Samuel [23].…”

Section: Introductionmentioning

confidence: 99%

Whirl Interaction of a Drill Bit with the Bore-Hole Bottom

Musa¹,

Gulyayev²,

Shevchuk³

et al. 2015

MME

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This paper deals with the theoretic simulation of a drill bit whirling under conditions of its contact interaction with the bore-hole bottom rock plane. The bit is considered to be an absolutely rigid ellipsoidal body with uneven surface. It is attached to the lower end of a rotating elastic drill string. In the perturbed state, the bit can roll without sliding on the bore-hole bottom, performing whirling vibrations (the model of dynamic equilibrium with pure rolling when maximum cohesive force does not exceed the ultimate Coulombic friction). To describe these motions, a nonholonomic dynamic model is proposed, constitutive partial differential equations are deduced. With their use, the whirling vibrations of oblong and oblate ellipsoidal bits are analyzed, the functions of cohesive (frictional) forces are calculated. It is shown that the system of elastic drill string and ellipsoidal bit can acquire stable or unstable whirl modes with approaching critical Eulerian values by the parameters of axial force, torque and angular velocity. The analogy of the found modes of motions with ones of the Celtic stones is established. It is shown that the ellipsoidal bits can stop their whirling vibrations and change directions of their circumferential motions in the same manner as the ellipsoidal Celtic stones do. As this takes place, the trajectories of the oblate ellipsoidal bits are characterized by more complicated paths and irregularities.

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Nonlinear Stochastic Drill-String Vibrations

Cited by 82 publications

References 23 publications

Frequency Analysis of Drill Bit Whirlings on Uneven Bottoms of Deep Bore-Holes

Frequency Analysis of Drill Bit Whirlings on Uneven Bottoms of Deep Bore-Holes

Modeling of BHA dynamic behaviors

Whirl Interaction of a Drill Bit with the Bore-Hole Bottom

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