Engineering Services

As drilling engineers, Merlin is concerned with ensuring that the system is capable of supporting the loads which will be imposed as the well is drilled. The system in this case, being the capability of the rig and surface equipment package, as well as the subsurface environment and its ability to withstand the loads which will be applied as we drill, measure, test and complete a wellbore. Our Engineering Services consist of a range of activities designed to ensure that your well can be drilled with the environment and equipment you have, and if not, what do you need to change or do, to achieve the well’s objectives. Examples of our work are illustrated in the panes below.

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Offset Well Review

The offset well review is where it all starts. It’s the foundation for reliable well delivery later on down the track. The objective, supportable assumptions which are validated through this exercise create a firm base for which to layer on the complexities involved in extended reach, high angle and complex wells. Reviewing 3 to 5 wells provides the most reliable data to verify friction factors and subsurface modelling assumptions, ensuring that subsequent conceptual well designs and feasibility studies are grounded in fact, with the lowest possible uncertainty.

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Feasibility Study

Accurately determine what it will take to reach a prospect from existing infrastructure. Define a dependable drilling radius for field development planning and/or to identify minimum rig specifications for your challenging wells. These are a few of the factors that a detailed feasibility study allows the drilling manager to assess. Merlin’s work is based on our knowledge of what’s possible, gained from working on the industry’s most challenging wells in over 40 countries.

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Problem Review

Fresh eyes and a lack of preconceived ideas is what Merlin brings to a problem review. Our focus on challenging extended reach wells enables us to provide a unique view on wells which have experienced difficulties during the construction process. By assessing drilling operations against an ERD methodology, we are able to identify areas where a revision to engineering or operational practices will yield performance improvements and a reduction in unplanned events.

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Detailed Well Design

Systematically building on the offset review and feasibility study outputs, the detailed well design is the last opportunity to make sure that critical risks are engineered out of the well architecture, rather than controlled through process. Merlin can undertake the detailed design work in its entirety or support in specific areas – whatever is necessary to create the greatest opportunity to assure drilling success. Specifically, we can support with trajectory design, targets, drill string and BHA design, casing scheme options, drilling fluid specification and properties, wellbore stability and casing wear assessments as well as any of the other routine and not so routine considerations which feed into a complex well design.

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Performance Optimisation

Successful, reliable well delivery is the first challenge to be overcome on many projects. Once that’s in the bag, how do we ensure we keep moving up the performance learning curve? Keeping the bit on bottom and drilling efficiently whilst minimizing energy lost through vibration, understanding system limits to optimize tripping speeds for drill pipe and casing, proactively managing planning and programming activities to gather and integrate lessons learned – all of these activities will allow us to drill further, faster, more efficiently, more often. Merlin’s integrated performance optimisation processes can facilitate this process quickly and efficiently.

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Related Case Studies

Consecutive BHA failures caused by bit and underreamer interaction

Merlin performed an independent review of two incidents that occurred while drilling a recent ERD well. The objective of the investigation was to identify the root cause of the failures and to propose engineered solutions to prevent similar failures occurring in future runs.

9-5/8″ Floated Casing Installation

This case study explains how we helped a client address a casing installation challenge by combining engineering and operations support with our TDH software.

Problem Formation Overcome With ERD Operational Practices

This case study looks at a multi-well development project from six fixed offshore installations with sub-sea satellite tie-back wells. Challenging high angle hole sections in large hole sizes through unstable shales and depleted zones prone to losses. Drilling performance suffering from multiple lost Bottom Hole Assemblies (BHAs) and significant Non-Productive Time (NPT).

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Merlin Tools

AV Calculator
Annular Velocity (AV) is one of the “Three Pillars” of effective hole cleaning in high-angle wellbores, with the other two being pipe rotation and the low-end rheology of the drilling fluid.
Stuck Pipe Tool
Description about stuck pipe tool goes here.

ERD Quiz

Test your knowledge on drilling extended reach, high angle and complex wells.

More ERD Services


Better trained people make better decisions. It is really that simple. If the plan is pushing the team out of their comfort zone, time in the classroom learning about the fundamentals and talking through critical success factors will improve reliability of well delivery.


Execution is make-or-break time. Effort and energy expended during planning needs to be harnessed and directed to assure operational success. Merlin can support your field operations with people that have real expertise and experience, and have the know-how and energy to drive success within your team.


We developed TDH to leverage our industry-leading process knowledge honed on the worlds most complex wells. What was available commercially didn’t cut it for us, in the way we need to use data when on location or in the office.