ENVIRONMENTAL CHALLENGES
The subsea nature of the project and remote island location presented a number of logistical and environmental considerations.
Careful control of drilling fluids was required to maintain bore stability while preventing environmental impact. The remote setting also required precise planning of logistics, equipment mobilisation, and communication to ensure safe and efficient delivery.
NAVIGATING DIFFICULT GEOLOGICAL CONDITIONS
Stockton mobilised its HDD spread to Carness Point on mainland Orkney, where a pilot bore was drilled through challenging geological conditions, including siltstone and sandstone formations.
The bore exited on the island of Shapinsay, where a prefabricated pipeline assembled in a single continuous length was prepared for installation.
To facilitate the pipe pull operation, the pipeline was pressure tested and filled with water to improve buoyancy, and a high-strength SDR6 pipeline design was selected to withstand installation forces. Stockton also used real-time communication systems (UHF and VHF radios) to coordinate operations across teams.
Once the bore was completed, the pipeline was successfully pulled through in a single continuous operation. Pulling forces remained well within safe limits, never exceeding 50% of the pipeline’s yield strength.
Despite the extreme length, challenging geology, and remote location, the installation was completed safely and efficiently, delivering a vital piece of infrastructure for the island community.
