Drilling Into The Albermarle Sound

The bore into the Albemarle Sound was part of the Currituck County Mainland Water Treatment Plant Reverse Osmosis Expansion project. The concentrate water (or reject water) from the reverse osmosis process is brackish and must be discharged into a receiving water of similar quality. The County was forced to discharge the concentrate water at the mouth of the North River and Albemarle Sound, 21 miles away from the plant site, and approximately 1,800 ft. off shore where flow was high enough to result in complete mixing.

The plan is to install the 16 inch HDPE pipe via horizontal directional drilling from a bore pit on shore about 400 feet from the waterline, 2200 feet total. The project was awarded to Joe Spoloric, owner of RJS Utility, located in Kitty Hawk, North Carolina. Due to a riparian easement, a significant bend of approximately 18 degrees was required in order to remain within the easement boundaries. Had the pipe been drilled in a straight line from the staging area, the pipe would have crossed the easements of several adjacent riparian owners and the County would have had to obtain approval from multiple owners. To tackle this tough bore Joe purchased a Universal UNI-160x240. The Universal drill line evolved from the Contractors Machine Services (CMS) generation of directional drills, now being manufactured by Universal HDD (formerly Robbins), located in Lake Zurich, Illinois.

“In my opinion, the Universal UNI-160x240 offers the most power and performance per dollar than any other manufacturer in the business” say’s Joe, “with a 325 hp John Deere engine, 260 GPM Kerr pump and a 24,000 ft pounds of rotation torque from the Hagglunds radial piston motor, this machine will get the job done”.

The pilot bore was planned to be approximately 34 feet deep, including the water depth. A standard carbide steering bit 8” wide was utilized to make the pilot bore. As the tide subsided it was possible to begin locating the head by the walk over method using a DCI Digitrac Eclipse locator an EXL transmitter with a lithium battery.

After thirteen hours of drilling, spread over two days, the pilot hole was completed. “The machine drilled out very fast” commented Joe Spoloric. Oh, Joe is the operator too! “It is amazing how quickly the drill stem is ready to thread onto once my carriage is back” and “we punched out on the bottom of the Albemarle Sound just feet away from an anchored crane barge”.

Dean Bryant and Andrew Copeland, owners of MAD DAWG Incorporated, Prime Contractor for this project, located in Station, North Carolina, coordinated the crane barge, pipe fusion and diving operations. “Once we have all of the pipe completely fused we will float the pipe about 15 miles from the State Park Facility located on the Atlantic side through the Pamlico Sound using a tow boat and a trail boat to keep the pipe from straying” says Dean Bryant.

After a few hours, the towboat was visible coming around the point and we were very close to hooking up the pipe and start the back reaming process.

“You can’t pre-ream this ground”, says Joe Spoloric. “The plan is to use the UNI-Ring-Cutter hole opener connected directly to the trailing UNI Maxi-Packer and pull the pipe in direct”!

As divers submerge into the Albemarle Sound to connect the crane to the drill head and pull the drill string to the surface, Andrew Copeland’s team is preparing the tooling to connect to the drill string once the head is removed. Finally, after the seven-hour trip from the Atlantic side the pipe is brought to the crane barge and Andrew’s team uses a set of hydraulic tongues to remove the drill head and connect the swivel and hole opener tooling in preparation to begin pulling back. After four hours from drilling out on the bottom of the Albamarle Sound, the pipe and tooling are rigged and ready!

Utilizing MI-Swaco’s Max Bore HDD product supplied by Universal HDD, RJS Utility used a reclaiming system to keep up with the mud demand. “It is very important to get the viscosity correct and to keep back flow going”. The UNI-160x240 pulled the shot back in 15 hours. “We got tight in the bend” says Joe, “the hole opener tooling worked very well, the machine is very powerful and at no time did I feel we would get into trouble”.

As the first tool emerged from the ground into the entrance pit and mud was flowing strong, the packer became visible! It was a very good feeling of accomplishment! A lot of quality planning and the right equipment make difficult projects like this one possible. Now it is time for Dean and Andrew to connect the final phase to the outfall pipe.

At the end of the outfall pipe, a diffuser header was installed and anchored to the sound bottom with timber piles and stainless steel u-bolts. The header was designed to convey the build out concentrate flow of 1.67 mgd. It consists of a 14-inch diameter, 52-foot long HDPE pipe with (12) 2-inch diffuser ports. Each port is equipped with a 2-inch duckbill style check valve that is designed to achieve a velocity of 9 ft/sec at the build out flow. Only four, of the twelve ports, are required to maintain the desired discharge velocity at the current WTP capacity. The remaining eight ports are being reserved for future phases and are currently blind flanged.