A distributed parameter systems view of control problems in drilling

Meglio, Florent Di; Aarsnes, Ulf Jakob F.

doi:10.1016/j.ifacol.2015.08.043

Cited by 41 publications

(17 citation statements)

References 36 publications

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“…Proof 5: Consider a positive delay δ. Consider the two states α and β defined by (22)- (23). Slightly adjusting the method used to derive (48), we get the following equation satisfied by the output β(t, 1).…”

Section: A Control Lawmentioning

confidence: 99%

“…2) Interconnected systems An important focus point in the recent literature is the control of interconnected and cascade systems: Ordinary Differential Equations (ODEs) featuring hyperbolic systems in the actuation paths have, in particular, received a lot of attention [11], [15], [24], [40]. A recurrent motivation for studying such systems is the control of mechanical vibrations in drilling, where the hyperbolic PDEs correspond to axial and torsional waves traveling along the drillstring, while the ODE models the Bottom Hole Assembly (BHA) dynamics (see, e.g., [13], [23] for details). The strategy in most approaches consists in transforming the interconnected systems into cascade systems by canceling the reflection at the controlled boundary.…”

Section: ) Zero Delay Marginsmentioning

confidence: 99%

See 1 more Smart Citation

Delay-Robust Control Design for Two Heterodirectional Linear Coupled Hyperbolic PDEs

Auriol

Aarsnes

Martin

et al. 2018

IEEE Trans. Automat. Contr.

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Norway and DrillWell -Drilling and well centre for improved recovery Stavanger, NorwayWe detail in this article the necessity of a change of paradigm for the delay-robust control of systems composed of two linear first order hyperbolic equations. One must go back to the classical trade-off between convergence rate and delay-robustness. More precisely, we prove that, for systems with strong reflections, canceling the reflection at the actuated boundary will yield zero delayrobustness. Indeed, for such systems, using a backstepping-controller, the corresponding target system should preserve a small amount of this reflection to ensure robustness to a small delay in the loop. This implies, in some cases, giving up finite time convergence.

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Section: A Control Lawmentioning

confidence: 99%

Section: ) Zero Delay Marginsmentioning

confidence: 99%

Delay-Robust Control Design for Two Heterodirectional Linear Coupled Hyperbolic PDEs

Auriol

Aarsnes

Martin

et al. 2018

IEEE Trans. Automat. Contr.

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“…The set-valued force laws for reaction force λ b a and frictional torque λ b t can be formulated by using normal cones of the convex sets (11) and (13), respectively [18,22]:…”

Section: Bit-rock Interaction Modelmentioning

confidence: 99%

“…The dynamics of drill-string systems, including such rate-independent bit-rock interaction model, has been described by a variety of dynamical models. In [9,10,17,19,20,[23][24][25]28,29,32] lumped-parameter models for the axialtorsional drill-string dynamics have been proposed, while in [2,3,13,16] both finite-element based and distributed models have been developed. These models have been employed to study instabilities and axial and torsional vibrations of drill-string systems, and recently to investigate the effect of the AST on the ROP [37].…”

Section: Introductionmentioning

confidence: 99%

Modelling and dynamic analysis of an anti-stall tool in a drilling system including spatial friction

et al. 2019

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This paper investigates the effects of a down-hole anti-stall tool (AST) in deviated wells on the drilling performance of a rotary drilling system. Deviated wells typically induce frictional contact between the drill-string and the borehole, which affects the drill-string dynamics. In order to study the influence of such frictional effects on the effectiveness of the AST in improving the rate-of-penetration and drilling efficiency, a model-based approach is proposed. A dynamic model with coupled axial and torsional dynamics of a drilling system including the down-hole tool in an inclined well is constructed. Furthermore, the frictional contact between the drill-string and the borehole is modelled by a set-valued spatial Coulomb friction law affecting both the axial and torsional dynamics. These dynamics are described by state-dependent delay differential inclusions. Numerical analysis of this model shows that the rate-ofpenetration and drilling efficiency increases by inclusion of the AST, both in the case with and without spatial Coulomb friction. Furthermore, a parametric design study of the AST in different inclined drilling scenarios is performed. This study reveals a design for the AST,

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“…Control design in MPD applications traditionally restrict to the use of the choke valve (Meglio and Aarsnes, 2015). The choke valve is the variable restriction in the mud return flow from the annulus.…”

Section: Introductionmentioning

confidence: 99%

Identification and Optimal Control for Surge and Swab Pressure Reduction While Performing Offshore Drilling Operations

Tengesdal¹,

Holden²

2020

MIC

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In this paper, an unscented Kalman filter (UKF) coupled with a nonlinear model-predictive controller (NMPC) for a hydraulic wellbore model with multi-variable control and tracking is presented. In a wellbore, high drill string velocities in operational sequences such as tripping might result in surge and swab pressures in the annular section of the wellbore. To overcome these challenges, a controller incorporating safety and actuator limits should be used. A second-order model is used to predict axial drill string velocity downhole. With a NMPC specifying the block position trajectory, choke flow reference, desired backpressure pump flowrate and stand-pipe pressure, we can automatically supervise and control the pressure in the wellbore. To compensate for unmeasured states, an estimator is designed to predict the frictional pressure forces in the wellbore and filter noisy measurements. A stochastic approach for the hydraulic model is taken, including variance of the average fluctuations for the flow and pressure states. Comparing three NMPC configurations, the result of using an integration of the tracking error in the prediction model gave best offset-free tracking of the bottom-hole pressure. The controller compensates for the unknown fluctuations, and is shown to be robust towards model mismatch. Including the mechanical system in the NMPC prediction model, we can effectively constrain the predicted axial drill string velocity to reduce the pressure oscillations and achieve tracking of bottom hole pressure and choke differential pressure. The outcome is shown through extensive simulations to be an effective control strategy, reducing the pressure spikes while tripping.

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A distributed parameter systems view of control problems in drilling

Cited by 41 publications

References 36 publications

Delay-Robust Control Design for Two Heterodirectional Linear Coupled Hyperbolic PDEs

Delay-Robust Control Design for Two Heterodirectional Linear Coupled Hyperbolic PDEs

Modelling and dynamic analysis of an anti-stall tool in a drilling system including spatial friction

Identification and Optimal Control for Surge and Swab Pressure Reduction While Performing Offshore Drilling Operations

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