Dynamic Failure Analysis and Lifetime Estimation of Tool-string in Rotary Drilling System under Torsional-Axial Coupled Vibrations

Author(s):  
Idir Kessai ◽  
Samir Benammar ◽  
M.Z. Doghmane
Author(s):  
Kristopher D. Staller ◽  
Corey Goodrich

Abstract Soft Defect Localization (SDL) is a dynamic laser-based failure analysis technique that can detect circuit upsets (or cause a malfunctioning circuit to recover) by generation of localized heat or photons from a rastered laser beam. SDL is the third and seldom used method on the LSM tool. Most failure analysis LSM sessions use the endo-thermic mode (TIVA, XIVA, OBIRCH), followed by the photo-injection mode (LIVA) to isolate most of their failures. SDL is seldom used or attempted, unless there is a unique and obvious failure mode that can benefit from the application. Many failure analysts, with a creative approach to the analysis, can employ SDL. They will benefit by rapidly finding the location of the failure mechanism and forgoing weeks of nodal probing and isolation. This paper will cover circuit signal conditioning to allow for fast dynamic failure isolation using an LSM for laser stimulation. Discussions of several cases will demonstrate how the laser can be employed for triggering across a pass/fail boundary as defined by voltage levels, supply currents, signal frequency, or digital flags. A technique for manual input of the LSM trigger is also discussed.


1969 ◽  
Author(s):  
Jack W. Martz ◽  
James E. Sherlock ◽  
Jason R. Lemon

Author(s):  
Thomas Stoxreiter ◽  
Gary Portwood ◽  
Laurent Gerbaud ◽  
Olivier Seibel ◽  
Stefan Essl ◽  
...  

2020 ◽  
Vol 1 (3) ◽  
Author(s):  
Chien-Chih Weng ◽  
Mansour Karkoub ◽  
Wen-Shyong Yu ◽  
Ming-Guo Her ◽  
Hsuan-Yi Chen

Abstract Active and passive control techniques have been devised over the years to mitigate the effect of vibrations on drill-string life with varying degrees of success. Here, it is proposed to design a robust trajectory tracking controller, which ultimately forces the rotary table and the drill-bit to move with the same speed (speed synchronization), hence reducing/eliminating torsional vibrations from the drill pipes. A model of the rotary drilling system, which includes torsional stick-slip, is first developed; then, an integral sliding mode control with time-varying exponent (ISMC-TVE) scheme is developed such that the bit motion tracks that of the rotary table to mitigate the effects of the induced vibrations. The ISMC-TVE is able to control the transient stage of the drill-string system’s response, maintain the system in the sliding state even under abrupt or existing external disturbances, and guarantee asymptotic stability of the rotary drilling system. The Lyapunov stability theorem is used here to analyze the performance of the closed-loop system, and the simulation results showed that the ISMC-TVE law is capable of accurately synchronizing the bit and rotary table speeds.


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