Did you know the horizontal directional drilling global market was valued at $7.5 billion in 2020?
In the past few decades, horizontal directional drilling (HDD) has become a major part of the drilling industry. You may be one of the people who now use HDD when laying down pipes for clients.
Even if you’ve been laying pipes using HDD for a while, do you ever wish there was a simple checklist you could follow to keep projects on track
If that sounds like you, then keep reading for the directional drilling checklist you’ve been waiting for!
Getting the Right Equipment
When it comes to horizontal directional drilling, there is a fair amount of equipment needed to complete a project. Here is a list of the equipment:
- Horizontal drilling rig
- Power unit
- Power generators
- Water pump
- Slurry pump and mixing tank
- Drill mud supply
- Mud mixing tank
- Mud pump
- Drill pipe racks
- Drill pipe
- Exit mud storage
- Downhole survey system
- Downhole drilling tools
- Product pipe
- Sonde transmitter
You’ll also want to leave room on your list for a Ditch Witch locator, which works with your sonde transmitter to give you the location of the drill head while your team drills the pilot hole.
This list is not necessarily exhaustive; anyone working on an HDD project should do further research to determine the extent of equipment their project requires.
Getting the Permit
Before you can start any project, you’ll need to have a permit. There are a few steps involved in getting a permit for a horizontal directional drilling project.
First, you’ll need to create a geotechnical report. This report will include examinations of past geological surveys, but it will also incorporate new information.
This new information comes from collecting soil samples on a path parallel to the planned bore path. These samples help determine which soil layer would be best to dig through. They also indicate soil strength and possible groundwater conditions.
Using this data, you’ll decide on the specifics of the bore path. In addition to the information gathered from the geotechnical report, planners need to be aware of any potential underground obstacles like other pipelines and avoid them.
Once you’ve worked out the bore path, you can create a drill plan.
This plan will include information about the project like:
- The equipment and steering tools you plan to use
- The drill fluid plan
- Pilot hole procedures
- Reaming procedures
- Swabbing procedures
- Puling procedures
- Inadvertent return plan
- Your contingency plan
Once you’ve submitted this information and received approval for a permit, you’ll make the plan more detailed and then start on the actual project.
Protecting Your Workers
This step is ongoing throughout the whole process of drilling. Make sure your workers are wearing the proper PPE whenever they’re working.
PPE for you workers looks like this:
- Eye protection
- Hard hats
- Hearing protection
- Safety shoes
- Safety vests (if work is near roads)
- Leather gloves
There is also special electrically insulated equipment that workers should wear when near the drill path, when placing the voltage sensor in the ground, or when standing on the ground while touching the directional drill.
There are some items your workers should NOT wear when on the construction site like loose clothing or any kind of jewelry. Long hair should also be pulled back.
Directional Drilling: The Pilot Hole
Drilling the pilot hole is the first step of the actual project.
The pilot hole follows the bore path decided on earlier. The pilot hole is not that large since later steps will expand the hole’s diameter.
An electronic transmitter situated behind the drill bit sends back readings to a receiver that indicates where the drill bit is. These readings help the rig operator make the necessary adjustments to keep the drill bit on the right path.
Directional Drilling: Pre-reaming
During this step, the pilot hole is expanded to 1.2 to 1.5 times the diameter of the pipe that will eventually be going in the hole.
Once the drill bit has exited the bore path, your workers will replace the assembly with a reamer. This piece of equipment expands the pilot hole.
Once the reamer is set up, it goes back through the pilot hole opposite the way the drill bit came. It may take multiple passes for the borehole to reach the necessary diameter depending on the diameter of the pipe to be installed.
Directional Drilling: Pullback
This is the step where your team will install the pipeline
Once the reamer has expanded the hole enough, the pipeline is attached to the reamer by a pulling head and swivel. These pieces of equipment ensure the pipeline isn’t dislodged as it is pulled back through the borehole.
The rig then pulls the piece through the borehole, rotating it and circulating drilling fluids.
Conduit Installation and Finishing Touches
Depending on what type of pipeline your team installed, there may be an additional step where power lines, water lines, or fiber optic cables are threaded through the pipeline.
Once these are placed in the pipe, the rig makes a final adjustment of the pipeline.
HDD contractors then use pressure testing to make sure the pipeline is strong enough, and the entrance and exit pits are covered.
And that’s the end of the project!
Get Your Project Underway
Horizontal directional drilling is a growing sector of the construction industry, so being an expert on the process can only help you in your career. This checklist can serve as a helpful reference tool as you tackle your next HDD project.
If you found this article helpful, check out some of our other articles and expand your knowledge!