NEWS The Advantages of Close Tolerance Centralizers

24 February 2025

Why TUR-CT, UROS and UROS-CT can often outperform centralizer subs 

In challenging wells, centralization is critical to ensuring well integrity via proper casing and cement placement. Traditionally, operators have relied on centralizer subs—integral tools with pre-installed centralizers—for close tolerance applications. However, Centek’s close tolerance, highly flexible centralizers can often provide a more cost-effective, efficient, and reliable alternative. 

The drawbacks of centralizer subs 

Centralizer subs are utilized in close-clearance wells, particularly when wellbore restrictions and demanding under ream scenarios demand precise tolerances. However, these tools come with several limitations: 

• Higher Costs: Centralizer subs require additional manufacturing processes, increasing material and machining expenses.  

• Longer Lead Times: Custom-built for each application, centralizer subs often have extended manufacturing and delivery timelines, delaying operations. 

• Complex Installation: Being integral components, centralizer subs require pre-installation considerations, limiting on-site flexibility and complicating pipe tally. 

The Centek TUR-CT, UROS and UROS-CT advantage 

Centek’s TUR-CT, UROS and UROS-CT close tolerance centralizers offer a superior alternative, providing: 

1. Significant cost savings 

• Eliminates the need for specialized machining, reducing material and manufacturing costs. 

• Can be installed on standard casing joints, avoiding the higher cost of dedicated centralizer subs. 

• Reduces transport and logistics expenses, as fewer specialized components are required. 

2. Faster lead times and greater availability 

• Off-the-shelf availability compared to custom-built centralizer subs, cutting wait times significantly. 

• Easier procurement process, reducing supply chain bottlenecks. 

3. Reduced installation time and increased flexibility 

• Can be installed directly on-site. 

• Allows for last-minute adjustments, improving adaptability in the field. 

• No welding or machining required, streamlining deployment. 

Real-world success: proven performance in the North Sea 

Three recent case studies highlight the effectiveness of Centek’s closer tolerance centralizers in challenging well conditions: 

Case Study 1: Highly-deviated tight tolerance cement job 

• Challenge: A highly deviated well (66° inclination, 13,382 ft TD) required precise centralization within tight casing tolerances. 

• Solution: UROS was deployed, ensuring safe run-in-hole (RIH) without excessive drag. 

• Result: Casing reached TD successfully, with >80% cement coverage, achieving optimal well integrity. 

Case Study 2: Overcoming uncertain hole conditions 

• Challenge: Exploration well with uncertain hole conditions required a robust solution to prevent casing hang-ups. 

• Solution: TUR-CT provided enhanced standoff, ensuring minimal drag and smooth casing placement. 

• Result: Formation Integrity Test (FIT) confirmed the cemented interval’s ability to withstand downhole pressures, with a positive casing pressure test verifying well integrity. 

Case Study 3: Slot recovery & redrill in the North Sea 

• Challenge: The operator needed to run a full casing string to 2678m Measured Depth Below Rotary Table (MDBRT) through multiple casing sizes, tight tolerances, and an open hole section, with inclinations up to 72°. The wellbore passed through a complex salt formation with different mineral layers, requiring careful drilling practices to maintain well integrity and avoid operational challenges. 

• Solution: 140 UROS-CT centralizers (9 7/8” x 11 3/4”) were used with Protech bonded stop collars (8mm blades), configured with 1-2 centralizers per joint. 

• Result: No issues during onshore installation, successful casing run to depth, and cement job executed as planned, meeting all annular isolation objectives.

Conclusion: A smarter choice for well integrity 

By switching to TUR-CT, UROS or UROS-CT, operators can achieve significant cost savings, reduced lead times, and more flexible installation processes. These centralizers offer the same performance advantages as centralizer subs, without the drawbacks of higher costs and long wait times. 

As wells become more complex, the need for efficient, adaptable, and cost-effective solutions grows. Centek’s closer tolerance centralizers deliver the performance needed—faster, cheaper, and with greater operational flexibility. 

Talk to one of our Product Service Experts to discuss their suitability for your next well design.  

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