Effective centralization for conductors in-situ
Retrofit centralizers are fitted between the conductor and the guide after the conductor is already in place. They can also be used between existing pre-installed centralizers which are not performing. These units can be fitted at the splash zone level and on subsea guides.
Claxton has provided several styles of retrofit centralizer to clients all around the globe. Centralization is an area that may be neglected during the planning process for new wells, and ever-changing drilling schedules may mean that clients must react quickly to satisfy their priorities. Additionally, with platforms exceeding their originally anticipated design life, equipment needs to be upgraded or replaced. Our retrofit centralizers can be fitted causing minimal disruption to standard operations.
Claxton has extensive experience modifying and retrofitting centralizers and has a broad range of proven designs.
When to use retrofit centralizers:
- Where there are doubts about accurate conductor space-out during installation
- Where conductors are driven
- When centralizers were not fitted in the conductor guides at the point of installation
- To provide centralization for the guide where a previously installed centralizer has failed or is not performing as required
Loadings on this type of centralizer vary according to their location on the conductor and tend to be highest in the splash zone.
To provide the most suitable design, good communication with the structural team in charge of the asset is vital. Claxton can work seamlessly with all parties involved in the installation to devise a bespoke design to comply with structural requirements and fit the geometry and existent clearances.
The standard retrofit centralizer typically comprises of a segmented central can, usually three segments held together by hinges. Fins are mounted on the segments to provide the required clearance in the guide and extensions of these fins land on the guides upper cone to support the centralizer in place. The mechanism can be completely opened to fit around the conductor and has another setting to allow the centralizer to be run over connectors using retainer pins. Once the centralizer has reached the guide, these pins are retrieved, and the centralizer mechanism wraps around the conductor.
When the centralizer needs to be fitted between the guide and a previously installed centralizer, Claxton can provide a segment type retrofit centralizer which consists of two identical segments, each including two adjustable blades which are then installed in place with the help of rope access personnel at the splash zone level.
Throughout our many years of experience delivering this product, Claxton has developed numerous bespoke designs that adjust to specific structural demands or operational challenges. The key to our success is to gain a full understanding of the project goals so that we can deliver a solution which is suitable, safe and cost-efficient.
Our retrofit centralizers can be fitted causing minimal disruption to standard operations. Claxton has extensive experience of modifying and retrofitting centralizers and have a broad range of proven designs.
Our expert view
“Collaboration is the key to a successful retrofit centralizer project. Claxton works seamlessly with the operator and all parties involved to devise a practical solution to solve the challenge being experienced offshore. Solid preparation has the power to save considerable time and money during the offshore operations and more importantly, make sure the operation is carried out safely.”