In December 2023, Brownline contributed to the replacement of a gas pipeline under the Adour River in the French department of Landes. After years of erosion, the pipeline was at risk of becoming damaged. Using our Gyro Steering Tool combined with GPS track, the HDD crossing in the natural area was surveyed accurately.
The Adour River has its source in the Pyrenees and runs through southwestern France. This river carries 90% of all water in the Atlantic Pyrenees to the Bay of Biscay. For years, erosion has chipped away at the riverbed. This was the reason for the replacement of the gas pipeline near Aire-sur-l’Adour, installed in 1958. The position of the pipeline was not as deep as it had been when installed, and it was not at equal depth everywhere. This could cause the pipeline to become damaged if not replaced.
Accurate drilling in protected natural area
The natural area around the river is protected, which is why it was essential to minimize the impact of the HDD on the vulnerable nature. The pilot bore was surveyed with our Gyro Steering Tool to ensure the highest accuracy.
Our tool was deployed in combination with the GPS track, which allows us to navigate within centimeters of the desired exit point. In order to protect the natural area, the Pressure-While-Drilling module was used on this project as well. This module allows for continuous monitoring of the annular pressure. As a result, inadvertent returns in the marl and gravel layers were prevented.
Crossing river and meander
The HDD operations under the Adour River were carried out by Verbraeken Infra (Infra Group). A total distance of 508 m / 1667 ft was drilled under the main river and under a meander, cut off from the river, up to a depth of 26 m / 85 ft. The newly installed pipeline is a durable solution which will last decades into the future. After the completion of this project, the reliability and safety of natural gas transportation in this region can be trusted once again.