Minimizing Scale Deposition Through Surface Enhancement in Downhole Tools

Graham, Gordon Michael; Goodwin, Neil; Albino, Eduardo Henrique; Guan, Hui; Pinto, Hardy; Bezzera, M. C.

doi:10.2118/169781-ms

Cited by 15 publications

(1 citation statement)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One very common failure mode in the ICVs is inorganic salt scaling of the sleeve [], which impairs production by clogging the valve orifices. Scaling also increase the friction force on the sleeve which affects the actuation mechanism, sometimes stalling it.…”

Section: Applicationmentioning

confidence: 99%

Fault reconstruction for delay systems via least squares and time‐shifted sliding mode observers

Pinto

Oliveira

Hsu

2019

Asian Journal of Control

View full text Add to dashboard Cite

In this article, we address the problem of fault reconstruction in delayed systems by introducing a time-shifted sliding mode observer (SMO). While time-varying delays of arbitrary duration are considered in the measured output signal, the actuator fault is parametrized as a weighted sum of known regressor functions with unknown coefficients. The prediction scheme utilizes the variation of constants formula to obtain the present time estimate of the unmeasured state. The fault is also identified at present time by means of the continuous-time Least Squares approaches. Ideal sliding mode can be guaranteed in theory, even in the presence of such adverse delays, since there is no chattering in the output estimation error of the SMO. An application to petroleum engineering with numerical simulations is presented to show the effectiveness of the proposed method.

show abstract

Section: Applicationmentioning

confidence: 99%