How to Perform Influx Management With EC-Drill® Dual MPD

In deepwater drilling, effective influx management is critical. Conventional well control can be challenging and time consuming, because of the long choke line and narrow operating margins.

The EC-Drill® Dual MPD system is designed to handle influxes more efficiently by combining Controlled Mud Level (CML) with a closed-riser. This dual-system enables safe, fast, and flexible influx management – even with larger influxes – while minimizing applied pressure to the formation and surface equipment. 

This article explains how the EC-Drill® Dual MPD system works and walks though its two influx management options, step-by-step. 

EC-Drill® Dual MPD – Overview

Under normal operations, EC-Drill® Dual MPD functions just like the original EC-Drill® system, using CML to maintain precise wellbore pressure without the drawbacks of SBP-only setups. 

System Components: 

• Subsea Pump Module (SPM): Adjusts the fluid level in the riser to manage bottom-hole pressure.
• Riser Closure Device (Annular or ACD): Installed above the SPM outlet. It remains open during normal operations.
• Surface MPD Choke: Used to apply backpressure when required. Normally bypassed in CML mode. 
  
  

For all standard operations, the CML system alone manages the pressure. When an influx is detected, the Riser Closure Device is activated and the return flow is routed through the surface choke – enabling two different influx management approaches.

Case study: EC-Drill® Dual Gradient in Gulf of Mexico Deepwater

Influx Management Option 1 – Using the SubSea Pump Module (SPM)

Option 1 uses the SPM to control and circulate out the influx. The surface choke applies a fixed value of ~100psi to control possible gas expansion up the Mud Return Line (MRL). 

Below follows a step-by-step approach from regular operation, via managing an influx and back again to regular operations.

This image illustrates the system under normal operations. The Closed Riser Device above the outlet to the SPM (in green and yellow) is open and the Surface Choke (greyed out) is bypassed. Operations are in CML mode with the fluid level in the riser kept at desired level.

When an influx is detected the BOP is closed as illustrated below:

The influx could have been circulated out instantly without closing the BOP. However, the preference to date is to close the BOP and assess the situation before proceeding. 

The next step is filling up the level in the Riser to surface, as a safety precaution, and closing the Riser Closure Device:

The return flow is then routed through the surface choke and the choke is set to hold a fixed value of typically ~100psi. The Riser pressure setpoint is set slightly higher than the wellhead pressure to provide an extra safety margin.

The system is now ready to circulate out the influx and the BOP is opened. The standpipe pressure is kept constant by adjusting the Riser pressure with the SPM:

Once the influx is circulated out, the fluid level in the Riser is set according to the new well conditions. The Riser Closure Device is then opened and the surface choke is bypassed. Operations can now resume:

The influx is basically managed using the Drillers Method but with only one circulation. Instead of displacing the well to a higher density fluid, the riser level is adjusted according to the new well conditions.

By using the SPM as controller it continues to provide lift up the MRL. There is less pressure at the Shoe reducing the risk of exceeding the Fracture Gradient, and there is less pressure exerted at surface.

Influx Management Option 2 – Using the Surface Choke

Option 2 uses the surface choke to control and circulate out the influx. The SPM is bypassed, which adds a column of drilling fluid up to surface. 

The illustrations below show how the system moves from regular operations (left) to influx management mode (right):

The influx management process is identical to a regular SBP system, however the results are improved. CML typically uses a heavier density fluid for regular operations, and this fluid column will now go up to surface increasing the hydrostatic pressure. As a result the required back-pressure to control and circulate out the influx is less. This results in lower pressure at Surface and also lower pressure at the Shoe.

Note should be taken that to use this method, the well must be able to handle the added pressure from the full column. Otherwise the SPM cannot be bypassed.

Case study: EC-Drill® Dual MPD Influx Management

Why the Influx Management Options Matters

The dual-mode flexibility of EC-Drill® Dual MPD allows operators to respond to any influx event using the method best suited for current conditions. 

This versatility delivers key operational benefits: 

• Rapid detection and suppression of influxes
• Reduced flat-time through faster recovery
• Safer influx management with less pressure exerted on the formation and at surface
• Continuous pressure management without displacing the well
  
  

In essence, the system provides the efficiency of CML combined with improved influx management – a combination uniquely suited for deepwater environments. 

Learn more about how EC-Drill® Dual MPD helps you with Influx Management here. 

Conclusion

The EC-Drill® Dual MPD system enhances Managed Pressure Drilling by combining Controlled Mud Level and Surface Back Pressure techniques. 

During standard operations, it performs as a CML system, delivering precision and efficiency. When an influx occurs, it can seamlessly switch to closer-riser mode for controlled, low-risk influx management

Whether using the SPM-controlled method (Option 1) or the surface choke method (Option 2), EC-Drill® Dual MPD provides safe, predictable, and fast influx management – helping operators drill deeper and more safely in challenging offshore conditions. 

Key Takeaways

• EC-Drill® Dual MPD combines Controlled Mud Level (CML) and Surface Backpressure (SBP) for precise influx management.
• Two management modes — SPM-controlled and surface-choke-controlled — allow flexible influx management strategies.
• Operators can switch modes without fluid displacement or added flat time.
• The system reduces pressure at the casing shoe, minimizing fracture risk.
• Proven to shorten time to recover from an influx event, and improve safety in deepwater operations.