Though pipelines are the safest and most efficient means of transporting fluids underground, the complexities presented by a marine environment need to be respected. With new environmental regulations and climate change impacts affecting industry productivity, businesses must create innovative designs for long-lasting pipelines.
Brisbane-based horizontal directional drilling (HDD) specialists, Pipeline Drillers Group, recently worked in conjunction with the Australian Bay Lobster Producers (ABLP) for Project Thenus, a seawater supply pipeline completed in 2022.
The project required Pipeline Drillers Group to design and deliver two 1100m lines of 500mm poly intakes as part of its client’s aim to improve sustainable aquaculture on Australia’s east coast. The pipeline was installed 35m below the ocean floor, which created a number of environmental difficulties.
The ground consisted of challenging indurated sands and sandy clays with low plasticity. However, the ground conditions also allowed the company to perform an advanced blind hole forward reaming process across both bores. This method allowed both bore holes to be built prior to the arrival of the marine spread, limiting exposure to marine costs.
Fickle weather conditions also caused major challenges for the construction team. Throughout the intake works, weather shifted from clear to overcast to rainy. This meant the on-site team had to perform quality work within a brief, volatile time frame.
Fortunately, the weather was generally favourable when the full marine spread was on-site, allowing both of the 1100m pipelines to be installed without potential demobilisation. If conditions had deteriorated, it would have caused substantial delays and additional costs.
Mitigating potential risks and challenges
In collaboration with marine support contractors, Pipeline Drillers Group developed a number of risk workshops to provide all involved parties with a clear understanding of the overall project requirements, particularly in relation to the dive and marine operations. This included:
• Finding bottom hole assembly
• Locating drill tools for barge recovery
• Clear communication between onshore and offshore crews
In order to undertake the tasks safely, Pipeline Drillers Group notified marine traffic and emergency services. Once the pipe was moved offshore, it was connected to the pull back BHA for overnight security. The tugboat remained connected to the tail end of the pipe, providing control of the pipe and a platform to manage the ballasting of the pipe during the installation process.
The future of Australia’s HDD industry
The project’s link to the cleanest sea water on the east coast will set it up as one of Australia’s best Aquaculture facilities, based in an ideal location, allowing for products to be distributed into the local and overseas markets in a timely manner.
The pipeline installation will also create a more sustainable method of production by minimising stress on Australian fisheries. The method of installation minimises the impacts to the environment and surrounding community by limiting the disruption above ground and utilising innovative technology to minimise the project’s carbon footprint.
Australia’s HDD industry is being called upon to provide ocean outfall and intake systems at an unprecedented level. Having crews and design teams capable of overcoming inherent challenges provides asset owners with the confidence that their prospective projects will be approached and completed correctly by competent contractors.
This sponsored editorial is brought to you by Pipeline Drillers. For more information, please visit www.pdgroup.com.au.
