Horizontal directional drilling (HDD) is gaining popularity in the construction sector. It is a cost-effective method to complete pipeline drilling projects with little interruption to daily life.
It has sparked attention since HDD projects do not require the excavation of whole road sections. But, the entrance and exit locations must be excavated and roped off.
While HDD is not new in terms of itself, it is just now becoming popular. Especially, in installing sewage and water pipes and replacing or renewing existing pipelines.
It is still in its infancy, in fact. A growing number of contractors increasingly recognize the advantages of HDD.
If you’re new to HDD, then no worries. You’ve come to the right place. Keep on reading for our full breakdown of everything you need to know about the process.
Horizontal Directional Drilling: The Basics
Drilling a pilot hole horizontally towards the opposite end of the intended path is part of the HDD procedure.
Contractors used a steel drilling rod to dig this hole. A back reamer is connected to the string and pushed back through the hole when the drill head emerges on the other end.
This reamer is somewhat more significant than the pipe’s diameter. The pipe is dragged through and installed once the reamer is removed.
When planning an HDD project, keep the following points in mind.
First Aid and Drilling Safety
At the start of every project, the first task should be to establish safety measures.
All safety protocols about handling machinery, chemicals, equipment, personal safety, and other matters should be strictly adhered to. It not only ensures a safe working environment.
But, it also eliminates the fear of workplace accidents. For minor injuries that you may handle on the spot, you should always maintain a first aid kit on hand.
Choosing the Drill Route
An HDD project should choose the shortest and straightest path feasible. This will allow the pipeline to be constructed in a continuous section.
To investigate the soil type, a proper geotechnical examination should be carried out. This will aid in the correct design of the crossing path. And, the development of the most efficient and cost-effective operating method. Including the use of suitable equipment.
The entrance and exit locations should not be more than 50 feet apart in elevation. And, they should be within eyeshot of above-ground obstacles. To prevent cross boring, you should identify any underground buildings within 10 to 25 feet (depending on a micro or maxi HDD application) of the path.
You’ll find that underground magnetics can truly ease this stage of the process for you.
Consider the Workspace Available for Entry and Exit Points
While it is true that HDDs take up more miniature workspace, depending on the size of the project, you should give enough space. A project requiring more extensive pipelines will require more drilling fluid, larger pumps, and mud storage equipment, among other things.
For example, a 1000-foot crossing may need a space of (100×150) feet for a Maxi HDD project. Ample space should be given at the exit point so that pipes may be joined and fused in a continuous string.
Pick the Appropriate Pilot Hole Curvature
One of the essential things to consider when planning the drill route is the radius of curvature.
Because curvature causes bending stress, you should maintain its bare minimum to decrease the pullback load. Because you must push the pipe through the hole, excessive curvature or too many curves may raise the tensile strength of the pipe, decreasing its resistance to collapse.
You should carefully select the entrance and exit locations to achieve the most significant radius of curvature in the drilling direction.
Calculate the Back Reamer Size
After drilling the pilot hole, you must enlarge it to the proper size with enough margin to enable the pipe to be pushed in comfortably.
This oversize or margin is about 1.2 to 1.5 times the pipe diameter and is determined by variables such as soil stability, hydrostatic pressure, drilling depth, and so on.
The pipe must resist vertical ground pressure without prompt support from the surrounding soil after it is placed. Typically, another reamer of the same size is used to remove residual debris and compress the borehole’s wall.
The Distribution and Viscosity of Drilling Fluid
Drilling fluid is a bentonite-water combination that is used to lubricate the hole during reaming and drilling. It also serves as a cleaning and stabilizing agent, preventing the hole from contracting and lowering drilling torque.
The drilling fluid must have the proper viscosity to suspend the cuttings. It must be continuously checked to ensure that the pumps are not overloaded and that the fluid is uniformly dispersed throughout the well. Uneven distribution may lead to borehole collapse or pipe pullback issues.
Pipe Handling Through Pullback
Because the pipe must be drawn in one piece without breaking, pulling the pipe back through the pipe may be difficult.
All fusion welding and inspection processes should be performed to guarantee good pulling.
To avoid bending, the pipe should be handled with care and appropriately supported. Other variables like exit and entrance, mudflow rate, drilling fluid circulation, axial tension force, and so on should be recorded at regular intervals.
Horizontal Directional Drilling Tips: Unlocked
If you’re new to the construction industry, it might take you some time to find the sweet spot between your budget constraints and using the best tools on the market.
We hope that our guide has shed some light on the process of horizontal directional drilling. Remember, when in doubt, always put the bulk of your focus on your drilling safety protocols.
And, if you liked reading our article, then you’ll love checking our additional tips and strategies. All of those will be available to you in our construction and industrial sections.