Ligonier Construction Company Installs Natural Gas Gathering System in Isolated Sproul State Forest
It's comforting to know that in this era of continuous expansion and development, there still exists such an unspoiled place as the jobsite where installation crews with pipeline specialist Ligonier Construction Company were dispatched recently. Their mission was a trenchless underground initiative that involved completing two important bores. Both bores were critical components to the success of a new pipeline gathering infrastructure for transporting clean-burning, energy-efficient natural gas to far-away markets originating from the depths of the energy-rich Marcellus shale formation.
Void of electricity, permanent homes and even the faintest of cellular phone signals, this remote jobsite, situated in the heart of Pennsylvania’s rocky, mountainous and picturesque Sproul State Forest, is reachable only by a primitive gravel road, meticulously carved out of the dense woods for one purpose only: extracting natural gas — and lots of it. The United States Geological Survey (USGS) estimates the total area of the massive Marcellus shale formation at approximately 95,000 square miles, ranging in depths from 4,000 to 8,000 feet, and containing an astonishing 410 trillion cubic feet of natural gas. That’s enough to supply the energy needs of the entire U.S. for hundreds of years.
Additionally, the development of the Marcellus shale has proven to be a boon for the Keystone state. Production of shale gas in Pennsylvania has generated tens of thousands of jobs and hundreds of millions in federal, state and local tax revenues. Pennsylvania has become a case study in how safe and responsible development of the nation’s vast oil and gas resources can create jobs and stimulate the economy. Independent small businesses, like Ligonier Construction Company, headquartered in the small Pennsylvania town of Laughlintown, are prospering as a result.
A New Drilling Opportunity
Ligonier Construction was founded in 1980 by David Herrholtz, and grew primarily by working in partnership with municipalities to install water and sewer lines. Over the years the company has expanded services to include site development, paving and demolition work. Ligonier was among the first Pennsylvania-based pipeline contractors to adopt horizontal directional drilling (HDD) — initially for installing water and sewer lines, then later, on natural gas trunk and gathering line jobs. The company also builds well pads, compressor sites and impoundments, a type of “holding pond” used to store water for the natural gas fracking process.
“We got interested in directional drilling shortly after the process was introduced,” says Gary Binkey, General Superintendent of Ligonier. “We started using HDD to install water services lines for local municipalities after purchasing a Vermeer D20x22 Series II Navigator Directional Drill. We’ve since added three more Vermeer drills with more power and capacity than our first D20x22 drill. HDD has given a tremendous lift to our business.”
Ligonier Construction has a long-standing working relationship with XTO Energy Inc. — an ExxonMobil subsidiary based in Fort Worth, Texas — having completed several difficult trenchless pipeline installations. Among the trenchless undertakings was an XTO project that involved installing a 12-inch polyurethane water line originating from the nearby West Branch of the Susquehanna River, and a 24-inch steel gas trunk line. The two lines were to be installed parallel to each other, spanning a distance of some 850 feet, through solid rock, at a depth in excess of 30 feet.
Familiar with drilling through the solid rock and sandstone conditions, Binkey chose the company’s Vermeer D330x500 Navigator Drill for both bores.
“We selected the D330x500 Navigator drill primarily because it has the power and drilling capability to bore through solid rock and shale, and pull the weight of the 24-inch diameter/1/2-inch-thick heavy steel pipe back through the bore channel,” Binkey says. “The bore plan specified that these two bores were to be installed on each side of, and parallel to, an existing 4-inch gas line within a 30-foot-wide span. Accuracy and alignment were critical to the success of the project.”
In addition to the challenges of difficult and limited access to such a remote jobsite location, no accessible communication sources and occasional encounters with curious rattlesnakes on hot, humid days, there were also environmental considerations. The two bores were situated directly beneath a 6 acre wetland and a prime habitat for the Northeastern bulrush, an endangered grass-like plant in the sedge family, one of only a handful of states in the Northeast U.S. where this disappearing plant species can still be found. For this reason, trenchless was the only viable installation option.
“The solid rock and shale ground conditions were fairly consistent throughout the entire length of both bores,” Binkey explains. “We maintained drilling depths in the 30- to 32-foot range to avoid any possibility of a frack-out. Also, due to the size and length of the bores, the rock conditions, and sensitivity for maintaining the environmental integrity of the drill site, mud recycling and reclaiming was critical. Finding the right drilling fluid mix is important for achieving maximum productivity on any HDD job but there was very little leeway for any amount of fluid or spoil to inadvertently infiltrate this jobsite.”
The drilling fluid and reclaiming system Binkey assembled for the XTO Energy project included a Vermeer SA-400 Pump and R9 x12T reclaimer with what Binkey describes as a fairly standard bentonite mix.
“The bentonite drilling fluid mixture delivered by the SA-400 pump into the drill averaged 400 gallons per minute, all of which was recycled back through the R9x12T reclaimer,” Binkey says. “The reclaimer did a great job removing the cuttings and providing a nice, clean fluid to recycle back through the drill again. We calculated that at upwards of 400 gallons on average per minute, we were able to recycle roughly 25,000 gallons of drilling fluid per hour, and keep cuttings away from the wetland. That’s an extremely significant savings.”
The first bore (for the water line) was completed in just over a week using a 6-5/8-inch standard rock bit. Production rates using the Vermeer maxi drill rig averaged approximately 250 feet per day; an efficiency quotient that pleased Binkey and his crews, especially given the tough, solid rock drilling conditions. The pilot bore was then upsized after only one backream, using an 18-inch reamer before the D330x500 drill with 486 horsepower engine and 330,000 pound pullback capability positioned the 12-inch polyurethane water line securely in place.
Binkey and crew then followed with the second pilot bore, situated approximately 15 feet to the right and parallel to an existing 4-inch gas line to accommodate the new 24-inch, 1/2-inch thick heavy steel trunk pipeline. Again, despite the tough drilling conditions, the second bore was completed without a hitch, followed by four reams of 18, 24, 30 and finally, 36 inches to upsize the bore to house the heavy steel trunk pipeline.
“Aside from the accuracy of the D330x500 drill when trudging through solid rock, it was on the pullback of the heavy, 850 plus feet of 1/2-inch-thick steel pipe where the drill really shined,” Binkey says. “It’s a powerful rig that is also accurate.”
The trunk gathering line installed by Ligonier Construction will eventually connect 54 natural gas wells that collectively, on average, are likely produce in excess of 540 million cubic feet of natural gas each day.
“Being able to recycle all the drilling fluid and keep any spoil from entering the wetland was a goal realized,” Binkey says. “We were also happy with the overall productivity we realized using dedicated Vermeer drilling and reclaiming equipment. There were environmental and regulatory representatives, engineers and U.S. Parks officials onsite almost constantly during setup and drilling, and all were impressed with the equipment and how we left the site when the job was completed. It was a high-profile project, and one that will set precedent for pipeline installations within the Marcellus Shale formation for years to come. We’re delighted to have been able to set a good example.”