Directional Drilling

Horizontal Directional Drilling (HDD) utilizes specialized equipment to install underground utilities without the need for trenching. Using state of the art equipment and electronics, we determine the depth, pitch and yawl like never before. This capability allows us to place new product in areas previously inaccessible and creates minimal disruption to the project site. So whether installing water main, force main, ducts for fiber optics or conduit for electrical services, we have the right equipment and personnel for the job.

Horizontal Directional Drilling (HDD, Directional Boring, Directional Drilling) is a method of installing underground pipelines and conduits from the surface along a prescribed bore path. The process is successfully used for installing telecommunications & power cable conduits, water lines, sewer lines, gas lines, oil lines, product pipelines and casings used for environmental remediation. Typical crossings include waterways, roadways, congested areas, environmentally sensitive areas and any area where other methods are more expensive or not feasible. Use of HDD is growing rapidly and is expected to continue to increase for the foreseeable future. Read more about why you should use horizontal directional drilling vs. trenching for your next project. Horizontal Directional Drilling (HDD, Directional Boring, Directional Drilling) is a method of installing underground pipelines and conduits from the surface along a prescribed bore path. The process is successfully used for installing telecommunications & power cable conduits, water lines, sewer lines, gas lines, oil lines, product pipelines and casings used for environmental remediation. Typical crossings include waterways, roadways, congested areas, environmentally sensitive areas and any area where other methods are more expensive or not feasible. Use of HDD is growing rapidly and is expected to continue to increase for the foreseeable future. Read more about why you should use horizontal directional drilling vs. trenching for your next project.

Directional drilling is a three stage process:

Pilot Hole

The first stage consists of drilling a small diameter pilot hole. Bore fluid is pumped through the drill rod to the drill bit where high pressure water jets and the drill bit grind the soils ahead of the drill stem. The bore fluid will also carry the cuttings back to the entrance pit at the drill rig. Tracking of the pilot hole is done by an electronic locator and a beacon which is located directly behind the drill bit. The beacon transmitter behind the drill head will send a signal to the locator at the surface directly above the drill bit to give the exact coordinates of the drill stem. A reading will be taken every 10 feet to check the depth, alignment, and percent slope of the drill head. Corrections will be made by the operator and locator to keep the pilot hole along the predetermined bore path. The speed of the pilot hole will vary upon existing soil conditions and the amount of steering which is required. Upon reaching the exit point, the beacon housing and bit is detached and replaced with a reamer.

Pre-Reaming

The second step is to pre-ream the pilot hole and enlarge it to a size sufficient to safely install the product lines. A reamer is pulled back and rotated while pumping bore fluid to cut and remove solids to enlarge the hole. Pre-reaming speeds will vary depending on existing soil conditions and the amount of cuttings that are removed from the hole.

Bentonite and additives will be used to ensure a clean and stable hole. Bentonite is used to create a "cake layer" around the outside of the hole during pre-reaming. This will help with the stability of the bore hole and with fluid loss or infiltration. Additives such as detergent and polymers are used to help break up the clay soils. A more evenly mixed drilling fluid will prevent any blockages inside of the bore hole.

Pipe Pullback

The final step is the pullback of the pipe within the pre-reamed hole. The drill rod and reamer will be attached to a swivel, which is utilized between the product line and the reamer to prevent any torsional stress being transferred to the product pipe. As the product pipe is pulled into the drill hole, bore fluid is pumped into the hole to provide lubrication for the product pipe.