Well Said | Knowledge Blog

Welcome to the Well Said blog!

kjlu@enhanced-drilling.com (Kjetil Lunde) — Fri, 26 Jun 2026 07:00:00 GMT

Whether you are planning a deepwater well, evaluating Managed Pressure Drilling technologies, or looking for ways to reduce operational risk, this knowledge blog brings together practical articles written for drilling engineers and technical decision makers.

You'll find technical explanations, comparisons, planning guidance, operational considerations and real-world experience from offshore drilling.

Who are you

Whether you're planning a challenging well, evaluating drilling technologies or looking for practical guidance on pressure management, staying up to date is essential. Well Said is written for drilling engineers, drilling managers, technical advisors and other professionals involved in offshore well planning and operations.

What Does Well Planning Look Like With CML

snlu@enhanced-drilling.com (Snorre Lutnes) — Fri, 12 Jun 2026 08:30:00 GMT

Controlled Mud Level (CML) is a Managed Pressure Drilling (MPD) method where Bottom Hole Pressure is controlled by adjusting the height of the hydrostatic column. This is achieved using a Subsea Pump Module (SPM) installed subsea with an inlet from the riser. By adjusting the fluid level in the riser, the SPM can increase or decrease the Bottom Hole Pressure as required.

In Which Drilling Environments Are CML Most Applicable?

snlu@enhanced-drilling.com (Snorre Lutnes) — Fri, 12 Jun 2026 08:15:00 GMT

The Controlled Mud Level (CML) method is applied across a wide rande of drilling environments to address operational challenges and improve well economics. In some environments, however, CML is used more frequently because its unique pressure management capabilities provide unique operational advantages.

What Are the Applications of MPD

snlu@enhanced-drilling.com (Snorre Lutnes) — Fri, 12 Jun 2026 07:15:00 GMT

The applications of Managed Pressure Drilling (MPD) proceed to expand. With increased familiarity, and improvements in MPD technologies and methods, the range of operations where MPD can be applied continues to grow together with the value it can provide.

In its early years, MPD was primarily associated with maintaining a near Constant Bottom Hole Pressure (CBHP) while drilling. Now, there are several MPD methods to choose from, each with different capabilities and application areas. As a result, MPD is used not only to enable drilling operations, but also to support cementing, optimize tripping operations, influence well design, and improve completion performance.

In this article, we explain MPD and the three main methods, and how their capabilities influence their application areas. By the end, you will hopefully have a clear understanding of its benefits and if this is the preferred method for your operations.

Understanding MPD

Simply put, Managed Pressure Drilling offers the ability to adjust and control the Bottom Hole Pressure (BHP) in the well.

Unlocking ESG Benefits and Cost Reductions With EC-Drill® Technology

snlu@enhanced-drilling.com (Snorre Lutnes) — Tue, 09 Jun 2026 07:15:00 GMT

Environmental, Social, and Governance (ESG) benefits and cost reductions do not have to contradict each other. In offshore drilling, shorter and more controlled operations can support both sustainability targets and financial objectives. EC-Drill® can play a significant part in achieving this by helping operators reduce rig time, material consumption, and operational complexity.

SBP and CML Connections in MPD: Operational Differences

snlu@enhanced-drilling.com (Snorre Lutnes) — Thu, 28 May 2026 09:00:00 GMT

MPD introduces additional operational considerations during activities such as connections, tripping and added displacements. Because maintaining a near-constant Bottom Hole Pressure (BHP) often requires controlled transitions when circulation stops and resumes, these operations can take longer compared to conventional drilling.

For rigs operating with high daily spread costs, even small increases in connection time become operationally relevant and are therefore closely monitored during MPD operations.

This article compares how Surface Back Pressure (SBP) and Controlled Mud Level (CML) manage connections during MPD operations, and how the two methods differ operationally when maintaining BHP during pump stops and start-ups.

Why MPD Connections Take Longer

Answering how long a connection takes is like answering “how long is a piece of string”. It varies. For connections in general, it depends on the rig, crew and operational requirements. In MPD operations, it also depends on how closely the BHP needs to be controlled and which MPD method is being used. Connections with MPD are generally slower because the pressure needs to remain constant when the circulation stops – and starts again.

How MPD Can Help Manage Unplanned Drilling Events

snlu@enhanced-drilling.com (Snorre Lutnes) — Thu, 28 May 2026 08:30:00 GMT

Unplanned drilling events can occur when actual well conditions differ from what was expected during planning. Events such as losses, influxes, differential sticking and wellbore instability may increase operational complexity, particularly in wells with narrow operating margins.

This article looks at how these events are typically managed and where MPD can support through pressure management and operational response.

Why pressure margins matter in drilling operations

Many unplanned drilling events are related to the operating window. If the Bottom Hole Pressure (BHP) becomes too high, the formation may fracture and lead to losses. If the BHP becomes too low, the well may take an influx or experience wellbore instability. In wells with narrow pressure margins, small pressure variations can create operational challenges, particularly during transitions between static and dynamic conditions.

Manage Drilling Losses

One of the most common unplanned events is going on losses, which can range from minor seepage losses to severe losses. Losses can be caused by exceeding the fracture gradient, drilling in unconsolidated formation, or drilling into loss zones such as Karstified formations.

Maximizing Savings with CML

snlu@enhanced-drilling.com (Snorre Lutnes) — Thu, 28 May 2026 07:15:00 GMT

Controlled Mud Level (CML) was initially introduced to enable drilling in wells where conventional approaches struggled to operate within the pressure window.

Today, the role of CML has expanded beyond drillability alone. In many offshore wells, particularly in deepwater and narrow margin environments, CML is used to support well design optimization, reduce operational constraints and improve completion results.

This article outlines some of the main operational and economic drivers behind the use of CML today.

Dual Gradient Effect: Improving well architecture

The Dual Gradient Effect is created when the fluid level in the riser is lowered, replacing part of the fluid column with air. This results in a curved static pressure profile with a lower pressure gradient at shallower depths.

How CML Enables Faster Kick and Loss Detection

snlu@enhanced-drilling.com (Snorre Lutnes) — Tue, 12 May 2026 08:15:00 GMT

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 is not just detecting a volume anomaly, but detecting it early enough to act on it. This is where the unique detection method of Controlled Mud Level (CML) differs from conventional surface-based monitoring.

How Can I Improve Kick Detection?

snlu@enhanced-drilling.com (Snorre Lutnes) — Tue, 12 May 2026 07:15:00 GMT

Are you confident in your well’s kick detection system? How early, and how confident, can you detect a gain or loss?

Kick detection is identifying unintended fluid gains or losses in the well – ideally as early as possible. Early detection allows for faster response, reduced rig time when managing it, and preventing an escalation. But traditional methods come with uncertainties, including delayed readings, interpretation challenges, and external factors such as rig movement.

In this article, we’ll break down the challenges of kick detection, examine the limitations of conventional methods, and explore how advancements like mass-flow meters and Controlled Mud Level (CML) technology are improving the process. By the end, you will see how precise well monitoring will reduce detection time and improve operational response.

What is Kick Detection in drilling operations?

First off, let’s have a closer look at what kick detection is, before we look at the methods and challenges.