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Unique Well Design Challenge for Conductor String in North Sea

Centek /29th September 2025/ OFFSHORE

In this project for a Norwegian operator, a challenging North Sea well required a 26" hinged centralizer capable of passing through a 30" wellhead restriction and then expanding to function in a 32" open hole — a configuration that standard solutions could not handle. Centek’s engineers created a bespoke hinged TUR centralizer, using in-house modeling and testing to validate the design. The final product was deployed on 24 conductor strings. In the first run, all seven conductors reached depth with no run-in-hole issues, no drag or hang-up, and full centralizer deployment, confirming the design’s effectiveness even in restricted zones.

Centek’s bespoke hinged TUR centralizer successfully met a complex North Sea conductor challenge, passing through tight restrictions and delivering flawless run-in-hole performance.

THE CHALLENGE

A complex well design in the North Sea presented a unique challenge for a Norwegian operator. The well required a 26" hinged centralizer that could pass through a 30" wellhead restriction and then expand effectively to operate in a 32" open hole—a demanding configuration that off-the-shelf solutions couldn’t meet. With a high-stakes environment, the operator needed a bespoke solution which could work with oversized casing couplings and which wouldn’t compromise performance.

THE SOLUTION

Our engineering team responded quickly to the customer request, designing a tailor-made TUR hinged centralizer. Leveraging our advanced in-house modeling tools and simulation techniques, we replicated the downhole environment and ran simulations to validate the design before manufacturing. Backed by extensive in-house testing, we confirmed the unique hinged TUR's ability to pass through the tight restriction and expand correctly in the larger bore section. Purpose-built for a specific operational challenge, the final product included:

  • Tailored design to meet the application with pinpoint accuracy
  • Deployment to meet the customer's timelines
  • Performance validated in real-world simulations and in-house testing

THE RESULT

Since development, the centralizers were installed on 24 conductor strings.

During the first job, the operator suspected a tight hole near TD and initially removed the bottom two centralizers as a precaution. After review, the customer decided to reinstall them and proceeded with the run.

All seven conductors were successfully run to depth with no RIH (run-in-hole) issues. Centralizers performed as expected with no signs of drag, hang-up, or tight hole complications. The trial confirmed that even with concern for a restricted section, keeping the full complement of centralizers in place ensured consistent, safe casing running. The use of 26″ centralizers on conductor casing has proven effective and trouble-free across multiple runs.

Operator noted no issues with centralization or RIH, reinforcing confidence in the design for large-diameter, near-surface applications. This case study demonstrates Centek’s ability to solve complex downhole challenges, without compromising quality or performance.

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