Modern HDD Tech Finally Brings Gas To Branson

October 2011, Vol. 66 No. 10

The company’s work in Branson focused on installation of gas mains and service lines with about 85 percent of the pipe installed by HDD, said Ed Libby, Woods Construction president and site supervisor for the work in Branson.

“We did do some open-cut work with trenchers and a small rock saw, but this project never could have been successfully completed without the capabilities of directional drilling,” said Libby.

“Most of the construction was in developed areas. To dig and hammer rock to put pipe in the ground would have made the cost too great,” Libby explained. “This was a project for which HDD was the least expensive way to perform the task.”

Woods Construction crews installed more than 100,000 feet of HDPE main line pipe in a mix of 2-, 4- and 6-inches. Most services were ¾-, 1¼- and 2-inches. Three hundred bores were made, ranging in length from 80 to approximately 1,320 feet. The average bore was 330 feet.

Rock sets job apart
Rock is what set the work apart from projects in ‘normal’ conditions, said Libby. Otherwise, it was a typical job.

“But the rock was extremely hard,” he stressed. “In some areas it was on a hardness scale of 31,000 psi. We did test breaks at various locations in the project and more than half the rock was more than 20,000 pounds psi.”

For all HDD work, Woods crews used two Ditch Witch JT3020 All Terrain (AT) drill units and one JT4020 AT machine. Equipped with a dual-pipe mechanical drive system, the AT system permits relatively compact drill models to effectively drill in rock as well as dirt and clay.

Libby said the AT machines completed all bores making it unnecessary to use machines with mud motors to drill through the rock.

“Using larger equipment with mud motors and the support equipment necessary would have been economically unfeasible,” said Libby. “Cost of the drilling fluid alone would have been 10 times more.”

The dual-pipe drilling system enables relatively compact equipment to drill through rock without a mud motor. The mechanical dual-pipe system delivers maximum downhole horsepower and operates on low volumes of drilling fluid. The AT design employs an inner rod to drive a rock bit, and the outer pipe steers the downhole tool for drilling pilot holes and provides rotary torque for the hole opener during backreaming.