Axial Excitation as a Means of Stick Slip Mitigation - Small Scale Rig Testing and Full Scale Field Testing

Forster, I.

doi:10.2118/139830-ms

Cited by 21 publications

(11 citation statements)

References 1 publication

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“…Forster 105 studied the mitigation of stick-slip vibration by introducing axial excitations into the drillstring. For this purpose, laboratory tests were conducted at the National Oilwell Varco Downhole Ltd. on small-scale vibration test apparatus designed to reproduce the stick-slip phenomenon and test different stick-slip reduction methods (Figure 20).…”

Section: Laboratory Studiesmentioning

confidence: 99%

Stick–slip vibrations in oil well drillstring: A review

Tang

Guo

Zhu

et al. 2019

Journal of Low Frequency Noise, Vibration and Active Control

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A survey of the literature related to theoretical and experimental studies on stick-slip vibration in oilwell drillstring is carried out in this study. It aims to explain key concepts and present the existing methods for studying this phenomenon. After briefly describing the stick-slip vibration related problems, theoretical models for such phenomenon are discussed including both coupled and uncoupled models. Discussion for experimental investigations including both laboratory and field tests are hereinafter addressed. This study aims to summarize the literature related to the stick-slip vibration, and help researchers in understanding and suppressing such phenomenon.

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Section: Laboratory Studiesmentioning

confidence: 99%

Stick–slip vibrations in oil well drillstring: A review

Tang

Guo

Zhu

et al. 2019

Journal of Low Frequency Noise, Vibration and Active Control

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“…4 for the model including AST). Besides, both torques are governed by a similar set-valued force law, see (15) and (25). As a consequence, it is not possible to distinguish between the wearflat torque and the set-valued frictional torque below the AST in numerical simulations with the model.…”

Section: Drilling Performance Variablesmentioning

confidence: 99%

“…However, the dynamics of the drill-string, the bitrock interaction and the (frictional) contact along the drill-string in a deviated well are not taken into account in this modelling approach. A different approach for ROP improvement is the selection of drill-string components, such as drill-bits or down-hole tools located at the BHA of the drill-string [4,5,15]. Down-hole tools can be either active [5,15] or passive [4,31,37].…”

Section: Introductionmentioning

confidence: 99%

“…A different approach for ROP improvement is the selection of drill-string components, such as drill-bits or down-hole tools located at the BHA of the drill-string [4,5,15]. Down-hole tools can be either active [5,15] or passive [4,31,37]. Active tools typically provide axial excitation during drilling, which can alter the effect of axial friction and consequently improve the drilling efficiency.…”

Section: Introductionmentioning

confidence: 99%

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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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“…Actuators were used to apply the numerically predicted displacement at the interface of bit and BHA to simulate deep downhole conditions. Forster (2011) demonstrated that axial excitations help in reducing stick-slip oscillations. An experimental rig was designed by Cheng et al (2011) to investigate dynamic behavior of BHA.…”

Section: Previous Studiesmentioning

confidence: 99%

Experimental Investigation of the Effects of Rotational Speed and Weight on Bit on Drillstring Vibrations, Torque and Rate of Penetration

Bavadiya

Alsaihati

Ahmed

et al. 2017

Day 3 Wed, November 15, 2017

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Drillstring vibrations namely axial, lateral and torsional vibrations are the primary reason for downhole tool failure and reduction in rate of penetration (ROP). Factors like bit design, bottom hole assembly, bit-rock interaction, rotational speed, wellbore hydraulics, weight on bit (WOB) and drillstring-borehole interaction affect vibrations, out of which only rotational speed and WOB can be changed in real-time to minimize vibrations. It has been a topic of interest to understand and model downhole vibrations, minimize them and find an optimum range of drilling parameters to increase the drilling efficiency. This article presents the results of experimental studies conducted on a fully automated drilling rig to examine the effects of drilling parameters on drillstring vibrations, torque and rate of penetration. The study is different in terms of the high-speed range and the use of axial vibration transmitter to measure the vibration severity as per ISO standards. Experiments were performed on two different rock samples with varying strength. Perfect hole cleaning with negligible fluid flow effect was assumed. Each experiment was run for an average of six minutes collecting an average of 120 data points which were then averaged out for analysis. Parametric study was carried out to analyze the impacts of bit strength to rock strength ratio, bit constant and intrinsic specific energy on torque using existing model. As the drillstring was stiff and small, torsional oscillations were not observed and only lateral and axial vibrations were studied. Effect of drilling parameters and vibration on ROP was studied only on soft rock sample as ROP on hard rock was too small to be recorded Once the input parameters for the analytic model were methodically selected they show good agreement with the experimental data. The results of the parametric study revealed that estimation of torque relies heavily on the bit constant. Axial vibrations increased when rotational speed was near to the natural frequency of the drillstring which resulted in increase of ROP. Type of formation affected the magnitude of lateral and axial vibrations. Reducing both rotational speed and WOB helps to minimize lateral vibrations in hard formations while reducing rotational speed can effectively reduce axial vibrations.

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Axial Excitation as a Means of Stick Slip Mitigation - Small Scale Rig Testing and Full Scale Field Testing

Cited by 21 publications

References 1 publication

Stick–slip vibrations in oil well drillstring: A review

Stick–slip vibrations in oil well drillstring: A review

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

Experimental Investigation of the Effects of Rotational Speed and Weight on Bit on Drillstring Vibrations, Torque and Rate of Penetration

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