In Webb County, Texas, near Laredo, a nine-member directional drilling crew with PUMPCO Inc. have successfully crossed under the Rio Grande into Mexico. The project involved boring and pulling back 2,200 ft of 36-in. pipe approximately 80 ft under the river’s bed. It was the last leg of the 17-mile long Impulsora Pipeline that will soon transport 504,000 MMBtu of natural gas per day across the border into Mexico.
The Impulsora Pipeline is part of the Nueva Era joint venture between Howard Energy Partners (HEP) and Grupo Clisa. Nuevo Era is responsible for designing, constructing and operating a pipeline system to transport supplies from the United States to end users in and around Monterrey, Mexico. The project involves the construction of two pipelines — on the U.S. side of the border in Webb County is the Impulsora Pipeline, and in Mexico, there are the 171-mile long Midstream de Mexico. Nueva Era will provide seamless service to shippers wishing to transport on both pipelines. Impulsora received its Presidential Permit on May 14, 2015, to construct, operate and maintain border-crossing facilities.
Installing the Pipeline
PUMPCO Inc. in Giddings, Texas, is the lead contractor for the bulk of the construction on the Impulsora Pipeline. With a workforce of approximately 1,800, PUMPCO is an industry leader in pipeline construction and has installed thousands of miles of pipe throughout Texas and other states.
PUMPCO’s crews started construction of the pipeline by using a combination of open-cutting methods and horizontal directional drilling (HDD).
According to Adam Nietsche, operations manager for PUMPCO, laying the 36-in. pipeline in Webb County went as easily and quickly as it could. “We used open trenches for the bulk of the work, but we also had some areas that called for horizontal directional drilling,” he says. “We had a total of four drills working on the project, including a Vermeer D1000x900 Navigator horizontal directional drill which we used to make the shot under the Rio Grande. That was the machine we determined was the best choice for this project from our fleet of 22 HDD rigs.”
The Vermeer D1000x900 horizontal directional drill is one of five Vermeer maxi rigs in PUMPCO’S fleet. The D1000x900 is equipped with twin Caterpillar C27 ACERT engines that produce a maximum of 92,000 ft-lb of rotational torque and 1 million lbs of thrust/pullback. With high-torque, low-speed Hägglunds hydraulic motors powering the rotary and carriage drives, the D1000x900 drill runs full torque and full rotary rpm simultaneously. Also, a floating vice allows the breakout system to clamp the full rod upsets during breakout of the lower and upper joints to help prevent rod wrap or windup.
Nietsche says the pipeline industry has shifted to an increased number of horizontal directional drills per project. “A successful drill project incorporates a variety of support equipment from cleaning units, water tanks, mud pumps, vacuum trucks, generators, drill strings and many others,” he adds. “Our team leverages this equipment to make certain each project is on schedule and completed in a timely manner.”
With miles of pipeline in place in Webb County, there was one major obstacle standing in the way of connecting the two pipelines — boring underneath the Rio Grande. To perform the bore, PUMPCO set up its equipment on the U.S. side of the river, right outside Laredo. The pipe was waiting for them to pull back on the Columbia, Mexico, side of the river. Once the product pipe was pulled into place, it would be capped and lay in waiting for the Midstream de Mexico pipeline to be connected.
“To complete the bore, we needed the members of our team on the U.S. and Mexico sides of the river every day,” explains Nietsche. “Many of our crewmembers had to cross back and forth multiple times a day, along with equipment. Luckily, the bore took place 10 minutes away from the nearest border crossing, but working on a job that involves two countries is always a little more challenging.”
PUMPCO’s crew used radios and some of the latest advances in locating equipment to ensure that the river and the border didn’t stand in its way of successfully making the cross.
The 2,200-ft bore called for the crew to drill 80 ft below the river bed and come up on the other side. Overseeing the onsite operations was PUMPCO site foreman Jason Walton. “We’ve completed two other bores under the Rio Grande before this one, and we’ve found that changes in the soil can be pretty dramatic, going from sand to rock, back to sand within a matter of a few feet,” he explains.
To reach the desired depth, the crew positioned the D1000x900 directional drill to start the pilot bore at an 8-degree angle and exited on the other side at 6 degrees. Throughout the bore, crews needed to maintain a 3,600-ft bend radius to make pullback of the 36-in. pipe possible.
Walton says they selected the Vermeer D1000x900 directional drill because of the distance they had to drill and the size of the product they were pulling back. For locating, PUMPCO’s crews used a Tensor Steering Tool System that uses a grid of magnetically charged wires to determine the location of the drill housing.
The Pilot Bore
With all the equipment in place, PUMPCO’s crew got started with the initial pilot bore using an 8 ½-in. barrel chisel bit. “In that first pass, we ran into a little bit of everything: sand, rock, cobble and gravel,” says Walton. “Honestly, the pilot bore took us longer than we first thought it would, but as we were coming through those different layers of material, we either needed to speed up or slow down our drilling speed. In sand, we went a little faster to avoid digging in, and then we slowed down for rock, gravel and cobble. It was a challenge.”
Widening the Hole
Before pulling back the pipelines, the crew needed to widen the hole to 48 in. “We started with a 20-in. rock reamer, then stepped it up from there with a 28-in., 36-in. and then 42-in. reamer. The final pass we made was with a 48-in. reamer before pulling back the pipeline into position,” explains Walton.
On average, the crew drilled around 500 ft a day, so each pass took them around four and a half days to complete.
Walton says the crew was running a 110 to 115 viscosity mud mixture throughout the process, which was primarily bentonite. PUMPCO’s crew used a similar mixture on its other two Rio Grande crossings.
With every pass, the PUMPCO crew got closer to finally being able to pull back product. In total, around a month was spent widening the bore path to 48 in. in diameter.
Finishing the Job
When the crew finally completed its last pass with a reamer, crews hooked a 1.3 million-lb swivel onto the drill string and the wielded-together pipeline waiting for them on the Mexico side of the river. Pulling back the pipe only took the crew around a day to complete. The 2,200 ft of pipe was connected to the 17 miles laid by PUMPCO’s other crews. After that, Walton and his crew packed up the equipment and got ready to move on to the next challenging job.
Nietsche and Walton are happy to have another successful Rio Grande crossing out of their way. “Having trained and experienced crews, along with investing in high-quality equipment, are the keys to taking on projects like this,” explains Nietsche. “We pride ourselves on having the best people and the best equipment; that’s what has helped us earn the reputation of being an industry leader in pipeline construction.”
No matter how many river crossings a crew has done, completing that final pullback is a good feeling. As pipeline industry experts, PUMPCO knows what it takes to accomplish a job of this magnitude. The company invests in its people and provides them with quality equipment, to help ensure jobs are completed on time and on budget.