Offshore Drilling Challenges Solved with Closed-Loop Systems
The 40-foot (12-meter) long subsea MPD system provided riser gas handling and early kick detection as soon as the BOP was connected to the well. No losses were encountered while drilling the upper carbonate structure using constant bottomhole pressure (CBHP) MPD. However, a two-barrel kick was detected by the MPD system and controlled while maintaining wellbore pressures.
Losses began when fractured lithology was entered and increased with depth. When total losses occurred, the drilling mode was switched to pressurized mud-cap drilling. An oil-based cap fluid was placed in the annulus to control annular pressures, while seawater was pumped down the drillpipe.
The MPD system, facilitated by the subsea RCD, enabled the well to be drilled to its targeted depth. Formation pressures were acquired in real time and logs were safely run.
Advances in closed-loop technology, such as marine RCDs, are extending significant problem-solving capabilities to offshore applications around the world.
Downhole pressure monitoring and the ability to contain, control and manage annular flow are resulting in significant improvements in safety, operational capabilities and well economics.
Upstream Pumping Solutions, Winter 2012