EC-Drill® Dual MPD Enables Casing Elimination in Gulf of Mexico Deepwater

Executive Summary

In a Gulf of Mexico deepwater well characterized by a narrow operating window and complex well architecture, EC-Drill® Dual MPD enabled elimination of a planned liner section by leveraging the Dual Gradient effect.

The result:

• Extended drilling sections
• Simplified well design
• Reduced operational time
• Lower casing and liner costs
• Improved deepwater drilling efficiency

This case demonstrates how EC-Drill® goes beyond conventional MPD by reshaping the pressure profile to match the well’s operating window.

The Deepwater Challenge: Why Are So Many Casing Strings Required?

What makes deepwater wells difficult?

Deepwater drilling operations often face:

• Narrow pressure margins between pore pressure and fracture gradient
• Fracture gradient at shoe lower than pore pressure deeper in section
• Multiple casing/liner set points
• High cost per additional string
• Long drilling and completion timelines

When the operating window is tight, conventional drilling forces frequent casing installations to stay within safe pressure limits.

Result: More sections. More complexity. Higher cost.

Learn more: EC-Drill® Dual MPD system 

Plot 1 – Deepwater Operating Window and Resulting Casing Scheme

Deepwater operating window showing pore pressure and fracture gradient profile leading to multiple casing strings in conventional drilling.

In this example, the pressure window narrows significantly with depth.
This requires multiple casing/liner set points to maintain well integrity.

Each added casing string increases:

• Rig time
• Material cost
• Operational complexity

The industry norm has been to accept this as standard practice.

The Solution: Using the Dual Gradient Effect to Extend Sections

How does EC-Drill® Dual MPD change the pressure profile?

EC-Drill® creates a Dual Gradient effect by lowering the riser fluid level, effectively shifting the starting point of the hydrostatic column.

This changes the pressure distribution in the well so that:

• The effective circulating density (ECD) better follows the operating window
• Pressure margins are optimized along the section
• Liner/casing strings can be eliminated

Instead of reacting to narrow windows, the system reshapes the well’s pressure profile.

Explore: EC-Drill® Controlled Mud Level technology

Plot 2 – Extending Sections Using the Dual Gradient Effect

Comparison of conventional mud weight and EC-Drill® Dual Gradient pressure profiles showing elimination of liner section in deepwater drilling.

The comparison illustrates:

• Conventional drilling requiring liner installation
• EC-Drill® pressure profile matching the operating window
• Extended drilling section without additional casing

In some cases, once the riser level is fixed at a reduced level, sections can be drilled conventionally — removing the need for continuous CBHP operation.

This is where EC-Drill® proves it is more than MPD.

Case study: EC-Drill® Dual MPD influx management 

Challenge Solved: From Reactive to Designed Deepwater Wells

With EC-Drill® Dual MPD:

• Liner elimination becomes part of the standard well design
• Wells are planned around the Dual Gradient effect
• Time to drill and complete is reduced
• Cost per well decreases
• Complexity is minimized

Even when fracture gradient at shoe is lower than pore pressure deeper in the section, the system enables safe drilling and completion.

This shifts deepwater drilling from reactive pressure management to engineered pressure optimization.

Why This Matters for Major Operators

For operators in:

• Gulf of Mexico
• Brazil pre-salt
• Guyana
• North Sea deepwater developments

The implications are significant:

• Fewer casing strings
• Improved NPT performance
• Reduced total well cost
• Better well architecture flexibility

For high-volume campaigns, such as multi-well developments, the cumulative savings are substantial.

Additional reading: Riserless Mud Recovery (RMR®) system 

EC-Drill®: More Than Conventional MPD

EC-Drill® Dual MPD is not limited to:

• Constant Bottom Hole Pressure (CBHP)

It enables:

• Dual Gradient drilling
• Negative operating window drilling
• Section extension
• Deepwater optimization

It functions as both:

• An enabler (making wells drillable)
• An optimizer (improving already drillable wells)
•  

Watch the Technical Webinar

Explore how EC-Drill® Dual MPD is putting an end to frequent casing and liner installations in deepwater drilling.

👉 Watch the webinar: Deepwater MPD – Introducing EC-Drill® Dual MPD

Conclusion

EC-Drill® has established casing and liner elimination as a standard approach in deepwater drilling by leveraging the Dual Gradient effect.

It enables:

• Drilling in negative operating windows
• Extended sections
• Reduced casing requirements
• Simplified well design
• Lower total well cost

In deepwater environments where conventional MPD is not sufficient, EC-Drill® Dual MPD is built for tough wells.