Can-do-mentality reaches new peak in dredging project Jebel Dhanna

“When you deepen those two channels for us, can you also check whether they are deep enough?” It is a rather unusual question for our marine services. Usually, the design is handed over and it is up to Jan De Nul Group to execute it. However, if you want to reassure your client, you must dare to step outside your comfort zone. So for Abu Dhabi National Oil Company (ADNOC), we showed our added value at the drawing and engineering table.

Double interview with Kris Dumont, Lead Engineer Project Development & Conceptual Design, and Stefan Moens, Project Director.

Can you briefly describe the dredging project in Jebel Dhanna?

Stefan Moens: “The coastal waters in Abu Dhabi are relatively shallow. But the ever larger ships need increasingly deeper waters to reach ports without difficulty. And so the two access channels to the Jebel Dhanna port needed deepening. The objective: providing a safe passage for Very Large Crude Carriers and Suezmax tankers carrying crude oil. According to ADNOC, a depth of 17 metres should guarantee that. Or to be more precise: the client asked us to redo the design.”

Is the design of dredging projects new to Jan De Nul Group?

Stefan: “In most projects, we review the submitted design with a critical eye and merely “endorse” the design. Doing a design project ourselves from A to Z is much less common. But when this question came up, Jan De Nul Group’s typical can-do mentality kicked in. What do we have to check? Who has this expertise? How much time do we need? And before you know it, you just start doing it, with a lot of enthusiasm and ambition.”

What in the end proved to be the biggest design challenge?

Kris Dumont: “From the start, a very tight timing was imposed on us. At first, we were given seven months, but that was soon reduced to five. In this time frame, we had to work out the design of the channel, estimate the sedimentation, conduct a navigation study to determine the operational windows, assess the environmental impact and check the existing infrastructure of buoys, amongst other things. That we got everything done properly within the deadline is due to a successful collaboration, both internally and externally.”

What did this internal and external cooperation entail?

Kris: “We have a lot of knowledge in-house, but rely on consultants and universities for certain studies. Our good relations with these parties and good coordination were crucial. Equally important: the internal cooperation between my team and Stefan’s team: we from the office, they on site. For instance, Stefan translated ADNOC’s feedback on our proposals to me and knew how to place it in the right context. Open communication allowed us to meet customer requirements.”

Which customer requirements stood out the most, and how did you deal with them?

Kris: “For our client, it was particularly important that both Suezmax and Very Large Crude Carrier ships could safely reach the port of Jebel Dhanna and Ruwais. This requirement had an important impact on the design, such as the width of the channel for instance. There were also strict administra tive requirements. The documents that we submitted were subjected to strict review criteria. Each document thus went through a review process, including a solid dose of feedback. At the beginning of the project, the client was especially very sceptical. Little by little, however, we gained their trust and, in the end, ADNOC showed their appreciation for our approach and timely delivery – much to our satisfaction.”

In short: doubt turned into trust.

Stefan: “Indeed. Today, we are reaping the benefits of our determination and flexibility: other projects for this client are now up and running. For instance, we are building an artificial island amidst the oil fields – one of our biggest projects ever. But we also won a cable project: Lightning. For this project, we will be responsible for the design, installation, burying and protection of two cable clusters totalling almost 1,000 km. These will connect two islands in the Arabian Gulf with onshore converter stations. And perhaps the biggest vote of confidence: ADNOC itself is now asking us to participate in their tenders.”

Where does the project in Jebel Dhanna currently stand?

Stefan: “We started dredging works on 1 September 2023 and already delivered the first channel ahead of schedule. In February 2024, we will complete the second channel, thus completing the project three months before the pre-set deadline. Then it is usually over for us. But in that respect too, Jebel Dhanna is a special project: we guarantee that both channels will remain at depth for at least a year.”

Kris: “To handle sedimentation, we dredged the channel a little deeper. We now have so much experience with sedimentation models that we were able to keep additional dredging works to a minimum. We want to unburden the client as much as possible, both before and after the dredging works. Naturally, we will take that knowledge and experience with us to future projects.”

The 5 main ingredients of the design

Design: according to the client's boundary conditions, such as the predetermined depth and a vessel model, we determine all design parameters of the channel.  

Sedimentation: after having made our own estimation based on desktop research, we ask a partner to go into detail. How will sedimentation proceed, taking into account waves and currents, the type of material on the seabed and other factors?

Navigation: in this detailed study, we look at exactly how ships pass through the channel to determine the safe width of the navigation channel. We do this through simulators and in collaboration with external parties.

Environmental impact: our Marine Environmental Department (MARED) measures the turbidity caused on the environment surrounding the dredging works so that we do not damage sensitive habitats and species such as coral reefs and marine mammals. 

Infrastructure of navigation buoys: we examine whether the current infrastructure of the existing buoys is up to the new conditions. For instance, do we have to adjust the anchors and chains of the buoys? And are brightness and battery life still up to scratch?