When it comes to deepwater drilling, early kick and loss detection can mean the difference between a controlled operation and a long and unwanted well control situation. The challenge isn’t just detecting a volume anomaly, it’s detecting it soon enough to act on it. This is where the unique detection method of Controlled Mud Level (CML) comes in, redefining the meaning of “early”.
Traditional kick and loss detection relies on surface equipment such as:
While effective in many situations, these tools share a common weakness: they all depend on surface measurements.
In deepwater environments, where mud returns travel a long distance up to the rig floor, this delay is notable. By the time a conventional system registers a gain or loss, the event is already well underway. The result is larger influx volumes, greater well control complexity, and increased risk.
Mass flow meters have greatly improved kick and loss detection. However, they tend to fall short whenever the well is static.
The CML system takes a different approach. By introducing subsea sensors and using the riser as an active pit, it transforms volume monitoring into a dynamic, real-time process.
Two key monitors enable this:
These monitors create a live picture of system stability. Because they are positioned subsea, with the fluid level in the riser below the telescopic joint, the measurements are independent of rig motion, eliminating the uncertainty that affects surface readings. The result is a faster, more reliable signal when any volume changes occur — whether it’s a gain or a loss.
The Riser is also used as a Trip Tank for tripping operations. As a result, all monitoring is directly on the well when tripping in/out.
Case study: EC-Drill® Instant Kick Detection Demonstrated on Deepwater Well
Field tests showed the CML monitors detecting influxes 48 seconds faster than surface-based systems. An influx detected nearly a minute earlier is smaller, easier to manage, and is less likely to stop operations.
Here’s what happens when CML detects a gain:
The same subsea sensors that identify gains also detect fluid losses, instantly registering small negative volume changes that surface systems might miss.
Because a CML system continuously tracks the volume down in the well, even a small decrease in system volume triggers a signal. Operators can then react by slightly lowering the riser level to instantly mitigate the losses.
This proactive approach prevents the cascading effects of fluid losses such as:
In harsh weather environments, surface-based kick and loss detection is often challenged by rig motion and subsequent volume and flow fluctuations. The CML detection method with sensors subsea eliminates this entirely. The result is consistent accuracy and reliable volume control, even in heavy seas or high-motion conditions where conventional systems struggle to maintain precision.
Early detection reduces both the size and the severity of events. With CML, gains and losses are identified when they are still small, and regardless of ongoing operation. This means quicker recovery, less time spent managing the situations, and a lower likelihood of a well control situation.
CML’s unique kick and loss detection capability represents more than an incremental improvement — it’s a step change. By moving the detection system subsea, and turning the riser into an active, real-time pit - and a Trip Tank placed directly in the well, EC-Drill® transforms reaction time into prevention time.
The result:
In other words, CML doesn’t just help detect problems sooner — it helps avoid them altogether.