Analysis of Postbuckling Drillstring Vibrations in Rotary Drilling of Extended-Reach Wells

Tikhonov, V. S.; Safronov, Alexander I.

doi:10.1115/1.4005241

Cited by 23 publications

(9 citation statements)

References 12 publications

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“…The model and method of solution is presented in full details in this paper (see also previous publications - Tikhonov et al 2006, Tikhonov and Safronov 2008, and Tikhonov and Safronov 2011 that permit other experts to validate and replicate the results presented here. Consequently, we believe the new dynamic stiff string model presents innovative capabilities for the industry to model drillstrings with both stiffness and radial clearance.…”

Section: Why Did We Develop the New Dynamic Stiff String Model?mentioning

confidence: 83%

“…The 3D mathematical model of a drillstring in a well, used in the new stiff string model is described by Tikhonov (2006Tikhonov ( , 2011. The model includes a system of equations for lateral, torsional and axial modes of a drillstring, written as projections on axes coordinate system oe 1 e 2 e 3 , referenced to the wellbore ( Fig.…”

Section: The Mathematical Model Of a Drillstringmentioning

confidence: 99%

“…This assumption permits the simulation of drillstring whirl cases.  Dahl's elasto-plastic model is used as the friction model (Tikhonov and Safronov 2011).…”

Section: Fig 1 Coordinate Systemsmentioning

confidence: 99%

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Dynamic Model for Stiff String Torque and Drag

Tikhonov

Valiullin

Nurgaliev

et al. 2013

SPE/IADC Drilling Conference

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A dynamic stiff string torque and drag (T&D) model is presented that assumes steady state motion of the drillstring as its basis for calculations. Results are compared to previously published T&D models that are based on static equilibrium. The novelty of the new dynamic model is the ability to solve T&D operations of the entire drillstring from bit to top drive in reasonable time using standard engineering computers.The new approach is based on a 3D dynamic model of drillstring and BHA in an elastic borehole. It considers bending stiffness, torsional stiffness, contact forces, and friction with localization of contact points. A numerical method is described that has proven to have excellent convergence. Complete governing equations are provided and the method is described in detail to permit readers to replicate results.The dynamic model is compared to two static stiff string models. Comparisons are also provided for three conventional soft string models including the Lubinski-Paslay-Cernocky bending stress magnification factor. Three field case studies are presented for horizontal wells. One well is short radius with dogleg severity over 50 deg/100 ft and two wells are unconventional shale wells with doglegs up to 15 deg/100 ft. Predictions for surface torque and drag up and down for the new dynamic stiff string model are compared to the static stiff and soft string models. In many situations modeled the top-level results for surface torque and drag up/down are close enough for all six models to be within the uncertainty range associated with the commonly used, lumped-parameter friction factor. However, some major differences in hook load for sliding and slack off operations are observed, which are shown to be caused by differences in location and magnitude of contact force between the drillstring and wellbore. Further, significantly lower surface torque is predicted by the new dynamic stiff string compared to other models for one case history because of lower contact forces in the vertical section of the well. In fact, the key finding of this paper is that major differences are observed for contact forces for the new dynamic stiff string model compared to all five other models, including the two static stiff string models. These differences in contact forces are most significant when the drillstring has helically buckled or when doglegs in the wellbore are high. Contact forces have a large impact on local stress behavior, which is important for predictions of casing and drillpipe wear, drillstring fatigue, and failure points in the drillstring.Although several previous papers have published stiff string models there is no industry standard formulation. The main problem holding back the development of an industry standard stiff model is perhaps the complexity of the numerical algorithm and substantial running time. To address this problem, some previous stiff string models account for bending stiffness of the drillstring but not for radial clearance while others appear to model only portions of the drillstring ...

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Section: Why Did We Develop the New Dynamic Stiff String Model?mentioning

confidence: 83%

Section: The Mathematical Model Of a Drillstringmentioning

confidence: 99%

See 1 more Smart Citation

Dynamic Model for Stiff String Torque and Drag

Tikhonov

Valiullin

Nurgaliev

et al. 2013

SPE/IADC Drilling Conference

View full text Add to dashboard Cite

show abstract

“…Its core consists of a system of dynamic equations for lateral, torsional and axial modes of a drillstring (Tikhonov et al 2006(Tikhonov et al , 2008(Tikhonov et al , 2011. Its core consists of a system of dynamic equations for lateral, torsional and axial modes of a drillstring (Tikhonov et al 2006(Tikhonov et al , 2008(Tikhonov et al , 2011.…”

Section: Torque and Dragmentioning

confidence: 99%

Live Well Display & Automated Data Analysis To Improve Timely Well Control & Drilling Optimization Decision-Making In MPD Operations

Gumus¹,

Pobedinski²,

Hannegan³

et al. 2014

Day 1 Mon, May 05, 2014

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A state-of-the-art MPD system should have not only highly accurate sensors measuring critical mud flow data and PLC automated chokes to precisely maintain desired annular pressure, but also the ability to aggregate, analyze and display this real-time information on monitors on the rig floor and in remotely located centers. In the past, this flow monitoring and detection capability that was primarily based on mass flow balance has helped safe and effective drilling of complex wells through early identification and interpretation of critical events such as kicks vs. ballooning and has enabled the safe drilling of prospects deemed un-drillable using conventional technology. This paper describes a number of enhancements including the system's ability to display and analyze not only the critical parameters of drilling hydraulics, but also other information that allows looking at the totality of the closed-loop system from different perspectives. It provides just-in-time engineering that improves the decision making process in time sensitive scenarios by increasing awareness and decreasing reaction time. It does this by utilizing a user friendly "live well display". The real-time MPD automation software platform that has been developed allows the conducting of advanced well hydraulics and drilling dynamics simulations, providing engineering calculation tools and customizable plug-in controls for multiple hardware components.By employing real-time models such as hydraulic, well control, swab-surge and T&D, the system displays information from different perspectives and aids in understanding what are the real limits during a drilling operation. The expandable database structure allows capturing more valuable data while continuity of data streams is secured with implementation of "heart beat" technology. The ability to control not only chokes but multiple components such as RCD, PRV, remote valves etc. provides further automation possibilities and minimizes the possibility of human errors. Finally, putting engineering and operational analysis, real time drilling process control and even automated reporting on the same software platform maximizes operational efficiency and increases safety for people and rig equipment during well control events and MPD applications.

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“…Vibration is a fault of rotary machines that lead to serious results [1,2]. Steam-flow-excited vibration is a phenomenon of abrupt increased vibration which is induced by the steam exciting force within the turbine.…”

Section: Introductionmentioning

confidence: 99%

Catastrophe Performance Analysis of Steam-Flow-Excited Vibration in the Governing Stage of Large Steam Turbines With Partial Admission

Li¹,

Guo²,

Yu³

et al. 2013

Journal of Energy Resources Technology

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Steam-flow-excited vibration is one of the main faults of large steam turbines. The catastrophe caused by steam-flow-excited vibration brings danger to the operation of units. Therefore, it is signiflcant to Identify the impact factors of^ catastrophe, and master the rules of catastrophe. In this paper, the quantitative analysis of catastrophe performance induced by steam exciting force in the steam turbine governing stage is conducted based on the catastrophe theory, nonlinear vibration theory, and fluid dynamics. The model of steam exciting force in the condition of partial admission in the governing stage is derived. The nonlinear kinetic model of the governing stage with steam exciting force is proposed as well. The cusp catastrophe and bifurcation set of steam-flow-excited vibration are deduced. The rotational angular frequency, the eccentric distance and the opening degrees of the governing valves are identifled as the main impact factors to induce catastrophe. Then, the catastrophe performance analysis is conducted for a 300 MW subcritical steam turbine. The rules of catastrophe are discussed, and the system's catastrophe areas are divided. It is discovered that the system catastrophe will not occur until the impact factors satisfy given conditions. Finally, the numerical calculation method is employed to analyze the amplitude response of steam-flow-excited vibration. The results verify the correctness of the proposed analysis method based on the catastrophe theory. This study provides a new way for the catastrophe performance research of steam-flowexcited vibration in large steam turbines.

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Analysis of Postbuckling Drillstring Vibrations in Rotary Drilling of Extended-Reach Wells

Cited by 23 publications

References 12 publications

Dynamic Model for Stiff String Torque and Drag

Dynamic Model for Stiff String Torque and Drag

Live Well Display & Automated Data Analysis To Improve Timely Well Control & Drilling Optimization Decision-Making In MPD Operations

Catastrophe Performance Analysis of Steam-Flow-Excited Vibration in the Governing Stage of Large Steam Turbines With Partial Admission

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