Wagenborg Foxdrill Complete Dismantling Project Offshore Congo – Long Read with Gallery

The Wagenborg Foxdrill team recently completed a very special offshore lifting project: the dismantling of a complete derrick on an offshore platform about 50km off the coast of Congo.

Dutch-based Dixstone Shipyard Holland BV awarded the complex derrick-removal scope to Foxdrill because of the specific skills and experience on derrick removal operations of the Foxdrill team. Dixstone is operating as a turnkey contractor for the platform conversion scope.

In other words, this would be a top-class derrick dismantling project, both in terms of the engineering and work preparation, as well as the techniques and rope access activities used.

Bart Oude Ophuis, Foxdrill’s Operations Manager, described background of the project, “This offshore platform is being converted into an unmanned production platform. That means, among other things, dismantling the derrick. And that’s no easy task, as the top of the derrick is more than 100m above sea level!”

Sander Hilbrink, Foxdrill’s Project Manager, added, “In addition, the cranes on the platform do not have sufficient lifting height to remove the upper part of the derrick. One option is to use an offshore crane barge. But then it is important to have a fixed timeframe for the work, which was not possible on this project. Moreover, the use of an offshore crane barge is a very costly affair.”

“We therefore proposed to our client a completely different approach to dismantling the derrick,” says Bart. “A method where the derrick is not removed in one piece, but rather in smaller pieces. The use of our Floating Ginpole proved that it was possible to dismantle the top of the derrick in sections.”

Wagenborg Foxdrill’s Floating Ginpole

“The solution with our Floating Ginpole offered the client the required flexibility in planning as well as considerable cost savings. The decision was therefore made quickly.”

The Floating Ginpole is a modular and flexible lifting solution developed in-house by Wagenborg Foxdrill. It is a tailor-made lifting tool for lifting work on high structures, consisting of connectable segments, each 4m long. Any desired configuration can, therefore, be built to carry out a customized lifting solution.

Using lifting cables and chain hoists, the ginpole is suspended in a structure, for example the derrick of a drilling rig. The top of the ginpole is equipped with a swivel and fitted with a lifting wire.

Tirfors, manual wire rope winches, position the ginpole into the right lifting position to perform each ofthe required lifting operations.

“And so began a challenging project for us,” continues Sander. “With challenges in terms of techniques to be used, engineering, work preparation, logistics, human resources and planning. We therefore set up a Foxdrill multi-disciplinary expert team for this special assignment.

“Our starting point for the project was to properly map the complete derrick, including the equipment. With the help of the original design drawings, all kinds of other documentation and an extensive survey by our rope access experts on the platform itself, we got a complete picture of the derrick, all the accessories and the dismantling options.”

“Our engineering and work preparation team then worked out the whole project step by step,” explains Bart. “We determined the correct lifting method for each structural component. We looked at how and where the lifting equipment needed to be installed, how the structural parts had to be separated, the intended lifting path to the platform deck below and how exactly the Floating Ginpole needed to be positioned for working on the top of the derrick.

“Finding out and documenting all this in detail was a huge task. But at Foxdrill we stand for ‘first time right’: on an offshore platform where we work at height, there can be no surprises or ambiguities. Everything has to be right so that the right equipment is on site, and we can do the job properly and safely. To prepare for the deployment of the Floating Ginpole, our planning team even organised a training course in our own training facility.”

Sander continued, “How nice it is when all the pieces of the puzzle fit together on site! First, we used winches to remove all the equipment from the derrick. Then began the daring feat of lifting at height: dismantling the upper structural parts of the derrick using the Floating Ginpole. A team of seven specialists worked on this for about three weeks: four rope access specialists carried out the work at height and three lifting specialists operated and monitored the Floating Ginpole from the deck.

“The work went like clockwork, right on schedule, “Sander concludes, “despite the tropical working conditions on the platform.”

Gallery

Source