Enabling Real-time Estimation of Borehole Parameters in Deep Drilling

In this work, the evolution of friction factors across the depth of a horizontal wellbore, downhole rpm and downhole torque are obtained using a distributed drillstring model. The model has been field validated for the off-bottom dynamics and is used to estimate along-drillstring friction factors. This model was later extended to include a bit-rock interaction (BRI) law to obtain the downhole rpm and downhole torque while drilling and has been validated against the field data. The advantage of the model used in this work is that it employs an adaptive soft sensor, robust to capture the disturbances occurring at the downhole. Only the top-drive measurements are used to estimate friction factors (static and kinetic friction coefficients) and the downhole parameters using the soft sensor. Once the bit engages, the BRI takes precedence, and the model stops estimating the friction factors. The model is used to generate estimates for friction factors, the downhole rpm and BRI for a well located in North America. It was observed that in both the cases, the estimates match closely with that of the data considered.