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Claxton subsea drilling template instrumental to Tombua-Landana

The Tombua-Landana template being installed…
The Tombua-Landana template being installed

This also marked a pause in Claxton’s involvement, during which some serious construction work was undertaken. First, a levelling-pile template was fitted over the well template, followed by four levelling piles, their correct alignment being assured using two guide pin slots in the Claxton template. The main tower-base template was then added and 12 foundation piles installed; thereafter there was just the small issue of adding the tower itself and then the topsides.

At this point Claxton returned to carry out another pivotal task in the development: the tying back to the platform of two of the first four wells. (CABGOC took the decision to delay tying back the other two wells in favour of drilling further platform wells.) Claxton prepared all the procedures for a process that began with the removal of corrosion caps from the 18¾-in high-pressure wellheads and the landing of 26-in conductors on both wells to provide conduits back to the platform’s well deck. “The challenge here was to ensure the correct space-out of the 14 conductor centralisers spread along the nearly 40 conductor pipe joints,” says Patterson. “Accurate measurement and careful calculations ensured that with the conductors locked onto their subsea wellheads all the centralisers engaged perfectly within the guides situated between the bottom of the tower and the platform.”

For each of the wells, following the installation of the conductor, 13.3/8-in and 10.3/4-in casings were landed and locked into the subsea wellhead and a high-pressure wellhead fitted to the former at the platform welldeck ready to accommodate the production tree.

“There is great satisfaction from being involved in complex projects like this one,” says Patterson, “when everyone is required to play their part to the very best of their ability to ensure the overall success of the venture.” In this case, Claxton’s contributions were both essential to the timely completion of the project, both firmly on the critical path to first oil from Tombua-Landana.

Subsea Drilling Templates from Claxton…

Over 55 major developments have benefited from Claxton’s subsea drilling templates. Claxton can design, rapidly manufacture and fully install templates that help to assure correct well / conductor alignment. Our team has experience of developing installation methodologies for challenging situations. Meanwhile our template design library has options for all soil types and multiple different slot arrangements and configurations – these designs can be modified with both speed and relative ease to suit numerous applications.


Contact us and we will put you in touch with the person best placed in our team to answer based on your unique enquiry. Our engineers are specialists in their own fields and ready to take on any challenge!

Asset life extension buyers guide Asset life extension buyers guide
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Asset Life Extension Buyers Guide

Download our structural asset life extension buyers guide for details on slot recovery techniques, centralizers and replacement platform guides.

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Asset Life Extension Case Study Pack

Download the Claxton structural asset life extension case study pack for details on slot recovery techniques, centralizers, replacement platform guides and other bespoke solutions.