Caspian Sea sisters
A project report from Van Oord’s two Damen Cutter Suction Dredgers 650
Manager Plant Department
Van Oord Dredging and
Marine Contractors bv
Van Oord is nearing completion of the Prorva channel connecting the Tengiz oil fields in Kazakhstan to the Caspian Sea. To support this substantial project, the company deployed numerous types of vessels such as work pontoons, crew suppliers, backhoe dredgers, dredge support vessels as well as four Cutter Suction Dredgers – two of which were the Ural River and Mangystau; the first two standard CSD650 vessels built by Damen.
Construction of the 72-km long Prorva channel was required to provide crucial sea access for the transport of construction modules for the expansion of existing oil production facilities. “The task of Ural River and Mangystau was to make the first – and shallowest – cut of the channel,” explains Van Oord’s Manager Plant Department Stefan Hansum. “We had two additional CSDs following behind to dredge even deeper.”
Delivered on time and on budget, the three-year Prorva channel project had its own set of challenges. “The north-eastern part of the Caspian sea is very remote. In particular, the Prorva region is very difficult to reach, with very little infrastructure or amenities,” continues Mr Hansum. This inaccessibility, in combination with the seasonal extremes experienced in the area, meant that well-planned logistics were paramount. “Dredging was only possible between April and October – meaning that our vessels, equipment and crew needed to return back to the base [in the port of Bautino] before the winter ice made dredging operations impossible. This made it necessary to plan well ahead. Because of the climate, deadlines could not be missed.”
Fine-tuning the design
Working within such tight schedules, the project team was keen to optimise both productivity and safety wherever possible. In this respect, the fact that the Ural River was delivered before the Mangystau meant that Van Oord could specify a number of additional modifications. “We had some ‘lessons learnt’ with the Ural River,” he notes. “These were on technical and operational levels, but also concerning safety. For example, a CSD of this size doesn’t normally have a cutter platform from where you can work safely in front of the cutter head.” After discussing this issue during a visit to Damen Dredging Equipment (DDE) in Nijkerk the Netherlands, Mr Hansum provided the DDE team with a hand-drawn sketch of his design request. “On the basis of that sketch Damen made the basic engineering, from which we produced the detailed engineering.” To address other aspects of the project-specific scope, other modifications included the installation of additional railings, hand grips and another type of deck crane, as well as repositioning the winches to optimise operations.
Another pertinent factor about this project was an effective environmental impact assessment, as the Prorva region is home to numerous endangered species of flora and fauna. In response to this, Van Oord cooperated closely with independent wildlife observers in order to minimise the impact on the environment. This increased attention to the sensitive local conditions also resulted in various vessel modifications: “This focused on minimising the risks and consequences of leaks – so we added drip trays and dry break couplings to the bunker connections and shut-off valves to the hydraulic connections so that, in case of a leak, we could shut off the system immediately. On an operational level, the crew also minimised their use of grease on board by means of an automated greasing system.”
Now that the Prorva channel project is nearly complete, how does Mr Hansum judge the vessels’ performance? “We did have some teething problems with the Ural River, which can be expected as this was the first standard CSD650 that Damen had built. But the cooperation that we had with them to solve these issues was fine. Generally speaking, these two CSDs display all the characteristics that we want in a vessel: safe, environmentally friendly, reliable, productive and highly automatable. And from the point of view of the crew, they were happy with how user-friendly these vessels were.”
An industry in growth
Kazakhstan’s oil industry is significant to both its own economy and the global oil supply. The country has over 150 oil fields, of which the Tengiz field is one of the largest. The 72-km Prorva channel – built for TenizService – will facilitate an increase in oil production of approximately 12 million tonnes per year.
In addition to the two CSD 650s Ural River and Mangystau, the ‘Damen contingent’ of Van Oord’s fleet working on the Prorva channel also included:
- Three Fast Crew Suppliers 1605; for transfers of up 23 passengers with a top speed of 30 knots.
- One Modular Multi Cat 2210; for dredge support duties.