Dagda; Source: Wagenborg Foxdrill

Dutch player wraps up ‘masterpiece in offshore lifting’ with derrick removal ahead of platform conversion

The Netherlands-based Wagenborg Foxdrill, part of the Royal Wagenborg group, has finished an offshore lifting project, which entailed derrick removal for Perenco’s platform repurposing project. Upon completion of the conversion work, the operator will be able to use the unit as a production platform off Congo.

Dagda; Source: Wagenborg Foxdrill

Dutch-based Dixstone Shipyard Holland, which is operating as a turnkey contractor for the platform conversion scope, awarded a derrick-removal deal to Wagenborg Foxdrill for the dismantling of the derrick from the Dagda jack-up drilling rig at the end of 2022. Wagenborg Foxdrill has now confirmed the completion of the derrick dismantling work about 50 kilometers off the coast of Congo.

The company describes this project as a “masterpiece in offshore lifting.” The firm’s contract scope encompassed the engineering and work preparation, as well as the techniques and rope access activities. An insight into the completed work was provided by Bart Oude Ophuis, Operations Manager, and Sander Hilbrink, Project Manager.

Ophuis explains that the rig is being converted into an unmanned production platform, which entails the dismantling of the derrick that is more than 100 meters above sea level. The existing cranes’ lack of sufficient lifting height to remove the upper part of the derrick made the project even more challenging, according to Hilbrink.

“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,” added Hilbrink.

Barring this in mind, Wagenborg Foxdrill used a completely different approach to remove the derrick, where the derrick was not removed in one piece, but rather in smaller pieces, thanks to the use of the firm’s floating ginpole.

“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. The solution with our floating ginpole offered the client the required flexibility in planning as well as considerable cost savings,” highlighted Ophuis.

Fitting all the puzzle pieces together

Hilbrink sheds more light on the challenges the company faced during the project in terms of techniques to be used, engineering, work preparation, logistics, human resources, and planning. He confirms that a Foxdrill multi-disciplinary expert team was set up for the assignment while the project’s starting point 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,” noted Hilbrink.

Afterward, the Dutch player’s engineering and work preparation team worked out the rest of the project steps and determined the correct lifting method for each structural component. Ophuis elaborates that the firm 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 work 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 organized a training course in our own training facility,” continued Ophuis.

Bart and Sander agree that this project is not only “a technical masterpiece” but also a testament to excellent teamwork. Hilbrink underlines that the firm used winches to remove all the equipment from the derrick and then began the lifting at height by 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. Despite the tropical working conditions on the platform,” concluded Hilbrink.

Last year, Perenco confirmed that oil was found in an exploration well in the shallow water Pointe Noire Grand Fond (PNGF) Sud license off Congo. The well was drilled with the Petrofor-managed Dagda 350-ft jack-up rig, which moved to the field at the end of August 2022.

Recently, Valaris announced that the Valaris 249 heavy-duty ultra-harsh environment jack-up rig was contracted by Perenco T&T Limited to drill one open-water appraisal well in the TSP block, offshore the southeast coast of Trinidad.

The assignment will begin in the second half of 2024, in direct continuation of the rig’s current program with another operator. The 2001-built Valaris 249 LeTourneau Technologies Super Gorilla Class jack-up rig can accommodate 120 people and its maximum drilling depth is 35,000 ft.