Atteris conducted a HDD design and methodology review which included the following:
Atteris was also involved in the on-site construction and observations throughout the construction operations were recorded. This covered the pilot hole drilling, reaming, borehole cleaning, pipeline pull, coating drain test and pipeline removal processes. It was found out that during the pipeline pulling process, coating damage (scoring and gouging) was observed. Sections with the worst coating damage were cut out and replaced or re-coated. To prevent this from recurring, it was proposed that buoyancy pipes be installed in the pipeline string and flooded prior to pull-in to reduce loading on the pipeline coating system. A fully documented timeline of events including lessons learnt was recorded to assist the client during future HDD operations.
