Fault diagnosis in managed pressure drilling using nonlinear adaptive observers. - Anders Willersrud; Lars Imsland (ECC, 2013)

Drillstring Washout Diagnosis Using Friction Estimation and Statistical Change Detection. - Anders Willersrud; Mogens Blanke; Lars Imsland; Alexey Pavlov 001 (IEEE Trans. Control. Syst. Technol., 2015)