Model-based stability analysis of torsional drillstring oscillations

Rudat, Jens; Dashevskiy, Dmitriy; Pohle, Linus

doi:10.1109/cca.2011.6044403

Cited by 6 publications

(2 citation statements)

References 15 publications

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“…The simplest models are just inertial masses modeling the BHA with a spring and damper for the drillstring (Navarro-López & Cortés, 2007;Rudat et al, 2011). The simplest models are just inertial masses modeling the BHA with a spring and damper for the drillstring (Navarro-López & Cortés, 2007;Rudat et al, 2011).…”

Section: Literature Reviewmentioning

confidence: 99%

For Better or Worse: Applications of the Transfer Matrix Approach for Analyzing Axial and Torsional Vibration

Shor

Dykstra

Hoffmann

et al. 2015

Day 3 Thu, March 19, 2015

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The response of the drilling system to axial and torsional vibration inputs has a significant impact on drilling performance. Usually the goal is to minimize dynamic response to limit the effects of potentially damaging phenomena in the low frequency range (e.g. bit bounce and torsional stick-slip) and high frequency range (e.g. axial chatter and torsional resonance). However, in some cases the goal is to maximize dynamic response, for example when introducing oscillation tools to overcome wellbore friction while directional drilling or to free stuck pipe. Whether the intention is to maximize or minimize, a suitable mathematical model is required. The model presented in this study uses the transfer matrix approach to predict how a harmonic vibration input propagates through the remainder of the drillstring. Novel features of the model include the ability to place the excitation source anywhere in the drillstring and to estimate damping effects due to Coulomb friction in directional wells.Model inputs include drillstring and bottom hole assembly composition, well survey data, surface equipment and drilling parameters. Drillstring components are modeled as spring or beam elements and the surface equipment is modeled as a mass-spring system. Bit-formation interaction is modeled as a spring, the stiffness of which can be adjusted to provide a boundary condition ranging from fixed to free. Damping due to material hysteresis and interaction with the drilling fluid is modeled using a velocitydependent term. Coulomb friction is modeled as an equivalent viscous damping coefficient. A harmonic excitation is specified at a given location in the drillstring and the responses at other locations in the system are computed via transfer matrices. This approach allows rapid characterization of the axial and torsional response of the drillstring in the frequency domain and may be applied to analyses of induced oscillation, such as from axial oscillation tools (AOTs), or unintended vibration, such as bit bounce.Case studies show that predicted frequency responses in the axial and torsional domain compare favorably with high sampling rate downhole and surface measurements, respectively. Additional case studies demonstrate how the model has been successfully applied to diagnose and resolve severe axial vibrations while drilling with roller cone bits. Finally, model predictions are compared with downhole acceleration measurements to evaluate effectiveness of axial oscillation tools while drilling with steerable motor systems. Recommended practices for device placement and drillstring configuration are provided based on the findings from these studies.

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Section: Literature Reviewmentioning

confidence: 99%

For Better or Worse: Applications of the Transfer Matrix Approach for Analyzing Axial and Torsional Vibration

Shor

Dykstra

Hoffmann

et al. 2015

Day 3 Thu, March 19, 2015

View full text Add to dashboard Cite

show abstract

“…More precisely, the bit-rock interaction takes the form of a discontinuous frictional force at the bit. The drillstring dynamics can be modeled as a lumped mass, representing the bottom hole assembly (BHA) inertia combined with a torsional spring, representing the drillstring stiffness [12], [13]. More complex models have been introduced in [6], [14].…”

Section: Introductionmentioning

confidence: 99%

Comparing Advanced Control Strategies to Eliminate Stick-Slip Oscillations in Drillstrings

et al. 2022

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In this paper, we present three methods to achieve reliable drillbit angular velocity control for deep drilling operations. We consider a multi-sectional drilling system with the bit off-bottom, which represents the system at the start-up of a drilling operation, e.g., after a connection. The three control procedures are all based on a distributed model for the drilling device. The proposed model has been field validated and considers Coulomb friction between the drillstring and the borehole. The first algorithm we propose combines the industry standard ZTorque controller with a feedforward component. The second procedure is based on a multiplicity-induced-dominancy (MID) design that corresponds to a pole-placement for the downhole state. Finally, the last class of controllers relies on a recursive interconnected dynamics framework. All the controllers are combined with a disturbance rejection procedure whose design is based on a switching-mode approach. These three algorithms are illustrated in simulations with field scenarios on several test-cases. Their complexities, effectiveness and limitations regarding industrial implementation criteria are discussed.

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Derivation and experimental validation of an analytical criterion for the identification of self-excited modes in drilling systems

Hohl

Tergeist

Oueslati

et al. 2015

Journal of Sound and Vibration

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Model-based stability analysis of torsional drillstring oscillations

Cited by 6 publications

References 15 publications

For Better or Worse: Applications of the Transfer Matrix Approach for Analyzing Axial and Torsional Vibration

For Better or Worse: Applications of the Transfer Matrix Approach for Analyzing Axial and Torsional Vibration

Comparing Advanced Control Strategies to Eliminate Stick-Slip Oscillations in Drillstrings

Derivation and experimental validation of an analytical criterion for the identification of self-excited modes in drilling systems

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