Between May and September 2024, Brownline has surveyed a large number of horizontal directional drills to install a new gas pipeline. Between Hoornaar and Utrecht, 23 km / 14 mi of new pipeline was installed, just a few minutes from Brownline’s head office in Meerkerk. For this project, many long HDDs were drilled and sensitive areas were crossed. That’s why Brownline’s advanced technology was instrumental in completing the pilot bores.
Background
The natural gas production in Groningen is being phased out. Consequently, the largest consumers of this low-calorific gas need to switch to high-calorific gas from abroad. A new 300 mm / 12” pipeline was therefore needed to connect a gas receiving station in Hoornaar with a control station in Reijerscop, near Utrecht. From there, several new pipelines were also needed to reach a power plant in Utrecht.
For this project, Brownline worked with main contractor A.Hak and subcontractor Van Leeuwen Sleufloze Technieken, who carried out these drills for Gasunie. Using the Drillguide Gyro Steering Tool, the pilot bores were surveyed efficiently and very accurately.
Long HDDs under fields and nature reserves
The 23 km / 14 mi between Hoornaar and Reijerscop were constructed almost entirely using directional drilling, with some trenched installations in between. For this route, 20 crossings were carried out, half of which were more than 1000 m long!
The longest crossing was 1563 m / 5128 ft. This HDD crossed the river Lek and a protected nature reserve adjacent to this river. To ensure the accuracy of a crossing of this length, our Drillguide GST was used in combination with GPS track. This allowed us to verify the drill head’s position from selected surface positions.
Brownline's Pressure-While-Drilling (PWD) service was also deployed on this long bore, to enable the continuous monitoring of the borehole pressure. This minimized the risk of inadvertent returns of drilling fluid under the river or the protected nature.
Besides the long river crossing, here are some other highlights in this project:
- Crossing the Zouweboezem, another protected natural area, with a 1000 m / 3280 ft HDD.
- Crossing another river, the Hollandsche IJssel, with a 1187 m / 3894 ft HDD
- Horizontal curves on multiple crossings. The largest was 44° over 300 m / 984 ft, in a crossing with a total length of 1164 m / 3819 ft. In two other long crossings, S-curves were made.
Highly accurate and safe drilling in Utrecht
In Utrecht, several more HDDs were surveyed with the Drillguide Gyro Steering Tool. In this urban environment, highway A2 was crossed and HDDs were made in very busy underground infrastructure. The Drillguide Gyro Steering Tool is ideal for these kinds of jobs, because our gyro is not influenced by external interferences.
Because this area of Utrecht was bombed once, Brownline’s UXOscope was also used on some of the pilot HDDs here. Using the UXOscope enables safe drilling by detecting any unexploded ordnance (UXO) in the ground. This ensured a safe and efficient installation of this part of the pipeline.
Brownline is proud of this contribution to this important energy project in our own backyard!
Gasunie made the following video about this project: