WorldWide Drilling Resource

16 JUNE 2022 WorldWide Drilling Resource® Preserving Shorelines with HDD Ocean Outfalls Adapted from Information by Future-Proof Solutions Since the country often experiences drought, Australia has various ongoing projects to diversify its water supplies. One specific type is increasing the construction and use of desalination plants, which are used to remove salt and impurities from seawater to produce a supply of freshwater. In a conventional desalination plant, water is piped from the ocean to the plant via an intake pipeline, before the desalination process is completed through methods such as distillation and reverse osmosis. The freshwater is harvested, and an outlet pipeline transfers the brine byproduct back to the ocean for diffusion. While modern desalination plants are designed for minimal impacts to the environment, their construction still contributes to environmental effects. Intake and outlet pipelines must be placed specific distances from shorelines, and this can potentially mean significant destruction of coastal dunes, bushland, coral reefs, and the seafloor to excavate and place the pipes. However, one way of minimizing harm - as well as the likelihood of damage and degradation to inlet/outlet pipelines over time - is by installing them via horizontal directional drilling (HDD). Using an ocean outfall technique - also known as a shore approach - HDD is used to bore from the pipe start point to its planned point of exit under the ocean. The pipe is pulled through the bored hole (usually with help from specialist marine vessels), and voila - the pipe is in place, with no need for digging and significantly damaging vulnerable ecosystems. Other trenchless technologies, such as microtunneling, can also be used. While the technique might sound unconventional, HDD ocean outfalls for various applications have been performed successfully for decades in different countries across the globe. Along with pipe for desalination plants, wastewater pipelines and communications conduits are also commonly placed with outfalls. Here are a few project examples: a Onslow Desalination Plant: Two HDPE (high-density polyethylene) inflow/discharge ocean outfalls were completed up to about 3115 feet for a desalination plant in Western Australia. a Grup Servicii Petroliere Offshore Landfall: Trenchless engineering for the Midia major gas pipeline project incorporated Romania’s first ocean outfall. It was approximately 4965 feet long and 885 feet deep under the Black Sea. a Tuas HDD Outfalls: Two seven-inch threaded cable landing outfalls were completed for a project in Singapore. The bores were roughly 1375 feet long for new international fiber-optic solutions. a Eyre Peninsula: Specialized front-end engineering design and construction evaluation was completed for the drilling and installation of four ocean outfalls for a desalination plant in South Australia. a New South Wales Northern Beaches: Telecommunications ocean outfalls of varying lengths were drilled and installed in the picturesque bays of Southeastern Australia. a A brine outfall HDD project took place on the east coast of South Africa, and was covered in the April 2018 issue of WWDR in the article, “Horizontal Directional Drilling on the Beach”. Drilling started at just over 10 feet above sea level, and continued uphill through challenging conditions to over 130 feet above sea level. HDD ocean outfall operations for the raw sea water intake of a desalination plant in Australia. Courtesy of UEA Trenchless Technology. DIR New & Used Tricones PDCs Drag & Claw Bits Drill Collars Bit Tipping Subs & Stabilizers HDD Bits & Reamers DTH Hammer & Bits Custom Fabrication Junk Mills / Fishing Tools Rod Henderson 661-201-6259 Eran Henderson 661-330-0790