STRAUME, Norway – Shell Offshore has contracted Enhanced Drilling (EDR) to supply a second EC-Drill Controlled Mud Level (CML) system for use in the Gulf of Mexico.
The managed pressure drilling system, named CML Closed Riser, is a further development of EDR’s EC-Drill technology. EC-Drill employs a subsea pump connected to the drilling riser to manipulate the fluid level within the riser and control wellbore pressure.
To handle small influxes and riser gas when drilling deepwater wells, the company further developed EC-Drill’s functionality by combining it with a riser closure device. A dual annular riser closure device will be deployed with the EC-Drill system with the dual annular joint located subsea just above the EC-Drill pump.
The system will perform normal operations with annulars open, functioning as a conventional EC-Drill system. However, should an influx occur, closing the annulars will allows a small influx to be circulated out of the well via the Closed Riser system rather than up the rig’s choke and kill lines.
The technology also allows dynamic pore pressure measurement and dynamic leak off testing so that the system can identify both low and high side well limits during the operation.