Innovative vibration model plays a key role in reducing non-productive time in drilling operations

In the transition toward renewable energy, high drilling NPT can be a showstopper for the economic viability of deep geothermal developments. Such initiatives are currently being considered for sedimentary basins in France, Belgium and Germany and drilling efficiency is a key success factor for these projects.

The 6n Degrees of Freedom Transient Torque & Drag project, funded by the Research Council of Norway, Equinor and Sekal and led by Chief Scientist Eric Cayeux at NORCE, set out to address two of the most complex and interrelated causes of NPT: cuttings transport and drill-string vibrations.

A Smarter, Faster Vibration Model

One of the project’s standout achievements is a new drill-string vibration model that accounts for lateral hydraulic effects—a capability not usually found in existing commercial tools. In fact, the model runs three times faster than the best available commercial alternatives.

– This model allows us to explore vibration problems more efficiently, says Eric Cayeux. This opens up new possibilities for innovation.

The model has already delivered practical value. For an oil company operating in Norway, it was used to analyze casing and wellhead wear, providing insights that would have been difficult to obtain with standard software. As part of the DigiWell initiative, the team also developed a new concept for vibration mitigation, which was successfully theoretically validated using the model—something that would have required extensive and unlikely modifications to commercial tools.

The model has also revealed limitations in existing torsional mitigation strategies, with some findings confirmed by in-memory downhole measurements. Its adaptability has led industry sponsors to advocate for releasing the software in open access, ensuring the broader drilling community can benefit from its capabilities.

New Insights into Cuttings Transport

While NORCE had previously developed a transient cuttings transport model now widely used via Sekal, its accuracy in large hole sections was limited due to the challenges of replicating such conditions in a lab setting, making it difficult to fully understand the specific material transport mechanisms at play.

To overcome this, the project developed a completely new model that is also compatible with large hole sizes. This highly detailed simulator has led to groundbreaking insights into how cuttings are transported and ground down in these environments, especially by combining the hydraulic flow with the complex displacement of the drill-string.

– This opens a new window for designing better strategies to manage cuttings transport in large hole sections, says Cayeux.

The model’s potential has inspired industry sponsors to support a follow-up research project, aimed at further exploring its applications and refining drilling strategies.

Toward a More Sustainable Future

The project marks a significant step forward in drilling technology. By improving the understanding and management of drill-string vibrations and cuttings transport, it directly contributes to reducing NPT—making drilling operations more efficient, cost-effective, and sustainable.