Contractor uses two machines to help push and pull pipe for a 7,000-foot bore job
Asked to name one of the most challenging horizontal directional-drilling jobs ever tackled by REM Directional, owner Joel Colgrove Jr. doesn’t hesitate for long: A 7,000-foot bore for a 42-inch-diameter natural gas pipeline, drilled 80 feet under the bottom of a roughly 65-foot-deep intercoastal waterway in 2008, outside of Lake Charles, Louisiana.
“What made it tough was the length (about 1.3 miles), plus it had rained a lot,” Colgrove explains. “So we had to bring in all our equipment on barges.” Furthermore, the ground was so spongy that REM had to dig a flotation ditch to hold a 7,000-foot-long section of pipe. As the name implies, flotation ditches keep the pipes floating on water, which reduces friction as they’re pulled through the bore.
“But when we got ready to hook up the pipe the next morning, we found all the water had drained out of the flotation ditch,” he recalls. “So we actually had to pull the pipe without any flotation, which creates a lot more drag on the pipe as its pulled.”
Things only got more difficult when the pipe got stuck just 300 feet from the end of the bore. “We never did figure out exactly why the pipe got stuck, but it was,” Colgrove notes. To finish the job, the Alabama-based company had to bring in its two Herrenknecht Direct Pipe pipe-thrusters and set them up on each end of the bore — one pulling the pipe and the other pushing it with 500 tons of force.
“The pipe-thrusters are huge (they weigh about 45 tons each), so it was a challenge getting them into the swamp and anchoring them down into the soft ground,” Colgrove points out. “We had to drive sheet piling all around them (to hold out groundwater) and build steel frames to hold them – provide them with the kind of support they need to do what they do.”
It took an extra two to three weeks, but the pipe-thrusters finished the job. Colgrove says the job exemplifies three core values at REM: a wealth of experience, new technology and a can-do attitude.
“If we didn’t have the pipe-thrusters, we would’ve had to redrill that bore,” he says. “Everything is about getting the work done. You really have no choice but to get it done, so you have to figure out a way to get that pipe in there. Some companies (in these situations) say they’re losing too much money and leave the job … and let the insurance companies fight it out.
“But I can’t bring myself to do that,” he concludes. “We’re not going to ruin our reputation like that.”