The dos and don’ts of horizontal directional drilling

On Horizontal Directional Drilling (HDD) projects, particularly for larger and more complex ones, there are some things you do want to see and some you don’t. HDD is not as simple as it appears. Maxibor outlines what to look for.

On Horizontal Directional Drilling (HDD) projects, particularly for larger and more complex ones, there are some things you want to see and some you don’t. HDD is not as simple as it appears. Maxibor outlines what to look for.

Horizontal Directional Drilling (HDD) is the design and installation of underground pipelines to serve as conduits for water, sewer, electricity, gas, telecommunications and hydrogen.

The technology makes it possible for drillers to direct their drilling equipment horizontally to create pathways through a wide variety of terrain ranging from alluvial sands, gravel and cobble to fractured or very hard rock.

The innovative design of bore pathways can solve many complex project challenges. Challenges including environmental, traffic, geological and underground utility congestion can be overcome.

There are various smarts in your approach to an HDD project. Outlined below are some dos and don’ts.

Dos of horizontal directional drilling – before drilling

  1. Getting the design right is paramount. The borehole needs to be constructible. Engage HDD designers with experience in delivering projects. Technical design knowledge is essential, but it is even better with understanding the equipment used and practical in-field involvement in delivering challenging HDD projects.
  2. HDD designer with experience. Engaging those with experience on more challenging and innovative HDD projects facilitates the exploration of solutions beyond the conservative traditional shorter and smaller diameter bores. Designers with experience add significant value by examining alternative HDD solutions.
  3. Geological investigation. It needs to be sufficiently representative of the designed borehole alignment. The geological conditions drive the Rate of Penetration (ROP) and equipment required, which drives the time, cost, and price for the HDD works. If there is doubt that the geological information is insufficient, the additional cost to achieve more certainty is a good investment for all stakeholders.
  4. Visit the site. Site visits and interaction with the asset owner are vital to designing and delivering the best HDD solutions. Informed design and delivery solutions can be explored when people are face to face at the site.
  5. HDD designer and installer relationship. Where there is a close relationship between the HDD designer and installer, they develop a productive and cost-effective design, construction methodology and a realistic construction schedule. It will optimise delivery outcomes for all stakeholders. Integrated design and construction HDD providers like Maxibor will achieve the best client outcomes.
  6. HDD equipment. Engaging an HDD delivery provider with fit-for-purpose HDD equipment to deliver the project is essential. On larger and remote projects, having equipment in good working order and spares is critical to projects running to schedule. An HDD provider with an expansive fleet of equipment allows for more adaptability in overcoming uncertainties.
  7. Other HDD resources. Engaging an HDD delivery provider with sufficient resources ensures that project management, drilling operations and HSEQ are all maintained and managed to good practice standards. Insurance coverage and financial capacity are among the other essential factors to consider.
  8. Cooperation and knowledge sharing. HDD design and delivery providers that cooperate and share add more value to your business. They increase the potential for optimised project outcomes. Look for their leadership within the industry on sharing technical knowledge, sustainability, strategic business development, workforce well-being and diversity.
  9. Safety and protection of the environment. This needs to be a top priority for all HDD providers. Look to the demonstrated actions of the key influencers and facilitators, such as the CEO and HSEQ Manager, in driving the right culture in an organisation.
  10. HDD risks. Numerous risks are associated with HDD, critical risks must be appropriately identified for each project, and actions must be implemented to mitigate those risks. Look for HDD providers with comprehensive HDD risk management systems that traverse the entire HDD risk universe and bring higher-level residual risks into the project management process.

Dos of horizontal directional drilling – during drilling

  1. Keep an eye on the wear on drill bits. Some operators forget to replace the teeth on a drill bit promptly. Like your dentist may tell you, good teeth are more productive. Watch those teeth and make sure they don’t get too much wear on them.
  2. Know the ground conditions. Properly maintaining equipment can be difficult. Selecting the proper tooling and fluids will help operators complete a job successfully and minimise equipment wear. The mud formula may also have to be adjusted from job to job. Variables can be extreme on some projects.
  3. Avoid drill damage by training the operators properly. Ensure they know how to stay within limits and not to push the drill too fast. This helps keep the drill rods in good condition.
  4. Clean tooling regularly because it last longer. Protect the threads on your tools. They need to be protected from gouging. A threaded cap or some tape saves a lot of stress in the long run. If there is thread damage, it damages everything it connects to down the drill string.
  5. Use drilling fluid. Drilling fluids will reduce the wear on the drill pipe and the tooling on the bottom of the drill string. Some in the industry believe they can do the project without drilling fluids because it’s a 30m bore instead of a 300m bore. That wears out the equipment.

Don’ts of horizontal directional drilling

  1. Designers not talking to installers. A disconnect between these two vital players will lead to a lack of constructible pipeline installation.
  2. HDD delivery providers are not allowed to talk to asset owners. An experienced HDD delivery provider can deliver a better project and add value if they have reasonable access to the asset owner to understand the project better, gain a greater appreciation and management of risk and identify opportunities.
  3. Accept conservative design solutions. Some HDD designers only design project solutions with which they are familiar. They do not explore more innovative solutions because they lack experience. This risk-averse approach limits the length of many HDD projects. In some cases, it has stopped HDD from being utilised.
  4. Believe HDD bores can’t go over 1 kilometre or one metre in diameter. HDD bores can reach 5 km and 1.6 m in diameter with the right design and equipment plus expertise.
  5. Engage an HDD provider with limited equipment, people and experience. Lower-cost solutions will provide less value in the long term. Bores will fail more often. If cost is a prime consideration, larger HDD providers should be supported to engage low-cost providers. There should be with oversight and access to the more prominent HDD provider’s expertise and resources.
  6. Accept the lowest price. The lowest cost means that the provider has been “tricky” in their quote through exclusions, limits on rock strengths, and other variations, all hoping to achieve a higher total price through variations.
  7. Believe HDD is too expensive. HDD is an increasingly viable alternative to open trenching as a long-term solution that combats the accelerating impact of climate change on infrastructure. It is the only solution in some cases, especially where environment and cultural heritage are priorities.

For more help and assistance on the design and delivery of HDD projects, contact the Maxibor team at www.maxibor.com.au

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