This month marks 10 years since we completed our first ever intersect crossing using Radar. The crossing was part of “De Nieuwe Warmteweg”, a district heating project. Contractor Visser & Smit Hanab carried out the installation of two 1,500 m / 5,000 ft pipelines, one below the other. The drill trajectory curved 60° and reached a depth of 60 m / 197 ft.
A challenge in all regards
Because the drillings took place in the centre of Rotterdam, in a densely populated area, this project had a number of challenges. The two pilot drills were scheduled two weeks apart. To minimize the inconvenience to the traffic in the city, pipe pullback had to be completed in a total amount of three days. This meant the project was under demanding time constraints.
The pipes could not be welded on site in Rotterdam. Instead, they were welded at the Maasvlakte beach in two 750 m / 2,500 ft sections. These were transported to Rotterdam by tugboat. This meant the shipping traffic in the Maashaven harbor was obstructed and the Erasmus Bridge was closed. The two sections were then welded together on a spud barge. Using 22 telescopic cranes, the pipelines were pulled in at the proper angle.
Why an intersect drilling?
One of the entry points was directly next to Hotel New York, a historic building without foundation piles. It was very important that there would be no inadvertent returns. In order to minimize the annular pressure, the crossing was designed as an intersect. Instead of building mud pressure for the entire length of the crossing, the pressure was divided over two halves.
The second reason to decide on an intersect was the narrow margin for entry and exit. By using two entry points, one on the Wilhelminapier and one on the Brielselaan, we knew exactly where we went into the ground.
This was still a high precision job. The space for deviation where the two drill heads would meet underground, was also very limited. ‘That’s why the Gyro Steering Tool and Radar combination was a great solution,’ says William Boere, who was involved in this project as driller. Radar allows the two drill heads to find each other, which enables you to intersect smoothly while maintaining the correct radius. ‘As a result, we only spent three days on each pilot drilling.’
Award winning project
This special project has won two industry awards. The Tytan Award and the No-Dig Netherlands Award were awarded to this project.
The complexity of this project, including the demanding time limit, the space limitations in the urban environment and the transport of the pipelines by boat, made these crossings very special. In addition, the use of the GST combined with Radar meant that this project took the spotlight.
We as Brownline are still proud to have been involved in this great and special project, and we are particularly proud of the great success of our first intersect drilling!
View a timelapse of the project in 2013 here