A Framework for Fault Diagnosis in Managed Pressure Drilling Applied to Flow-Loop Data

Data from a medium-scale horizontal flow loop test facility is used to test fault diagnosis in managed pressure drilling. The faults are downhole incidents such as formation influx, fluid loss, drillstring washout, pack-off, and plugging of the drill bit, which are important to detect and handle in order to avoid downtime and possibly dangerous situations. In this paper a fault diagnosis scheme based on an adaptive observer and the generalized likelihood ratio test is applied on the experimental data. The different types of faults are detected and their location are isolated using friction parameter estimates. Results indicate that the method can in most cases identify the type of fault, whereas the location is sometimes more uncertain.