Automated Dynamic Well Control With Managed-Pressure Drilling: A Case Study and Simulation Analysis

Summary The detection and control of gas kicks in oil-based mud/synthetic-based mud while drilling through narrow pore-pressure/fracture-pressure windows has always been a challenge because of gas solubility and mud compressibility. Continuous closed-loop monitoring of the well and automated early kick detection and control helps to keep the influx volume at a minimum before it reaches the well-control-threshold margin in the kick-tolerance matrix. This paper presents a case study and detailed analysis of the event through advanced simulations to examine the benefits of automated influx detection and control by use of a managed-pressure-drilling (MPD) system compared with a conventional-well-control method. In the case study, an automated-MPD system successfully detected and controlled a gas influx in oil-based mud while drilling in onshore western Canada. The analysis used dynamic well-control simulations to regenerate the event, and a close match with the field data was achieved. A sensitivity analysis was then conducted to study the effect of total response time on pressures at the surface and at the casing shoe during the application of the conventional “driller's method” of well control. The findings from the study demonstrate how automated early kick detection and control minimize influx volume and increase operational safety. The implementation of an MPD system with such capabilities significantly reduces nonproductive time by enabling influx circulation at full rate and eliminating the need for flow check, blowout-preventer closure, and operational delays inherent in conventional well control.