It can’t be stressed enough that, although geothermal drilling is done with all the same equipment and tooling as water well drilling, geothermal drilling requires a different mindset. Drillers who have done quarry work know what it means to punch holes in the ground to meet the footage demands of the customer. Geothermal work follows the same production drilling philosophy.
Mansfield, Ohio-based Jackson & Sons Drilling has gone so far to emphasize the difference in its business that the company has changed its marketing name to reflect the nature of its work – Jackson Geothermal.
The company currently operates 15 drills, with the bulk of its work on geothermal projects. For the first six months of the year, the company logged 508,000 drilled feet. The crew works within an eight-hour drive of Mansfield, focusing mainly on large projects, but will take on smaller geothermal projects. Geothermal manager Mark Southward says, “Seventy to 80 percent of our jobs are commercial geothermal projects.”
It was on a recent 92,110-foot project at the Green County Career Center in Xenia, Ohio, that the company raised the bar on productivity by setting a footage record using an Atlas Copco T3W. In a single day, driller Nick Sprowls and his helper, Josh Crawford, drilled 3,050 feet.
The 17-man crew operated seven rigs on the job to complete the project in 10 days, averaging 1,309 feet per rig each day. But the performance of individual drills on certain days helped them overall. For example, on two different days, two 20-year-old Atlas Copco TH55s each completed 2,440 feet of drilling in a shift.
The company doesn’t consider a hole completed until it is drilled and the loop is grouted in place. On this project, each well required setting the loop, then pulling the 20-foot surface casing for each 305-foot hole. Bedrock began at approximately 18 feet.
The day Sprowls completed 3,050 feet, his day began just after 7 a.m., logging his first rod at 7:30 a.m., and signing off on his last hole at 7:45 p.m. Sprowls averaged 2,064 feet a day for 10,320 feet in each five-day week. This is not uncommon for him. Year to date, Sprowls has logged 75,000 drilled feet on five different rigs with 25,455 feet from June alone.
Southward emphasizes that all his men work as a team, with no one standing alone. Owner Jim Jackson has gone to the extent of printing the name “Team Jackson” on uniforms worn by crew members to highlight the team effort needed for everyone to keep these numbers up.
Dave Tingley was the site foreman on the Green County project, and was a major reason for its overall success. Southward says, “Dave breaks in all the new rigs and keeps things moving smoothly. He may have been the driller setting the record that day if he hadn’t been supporting the crew on another task.”
Southward points out that all his drills use the Atlas Copco Secoroc TD40 down-the-hole hammer with the Rocket Bit. “We did 302 holes in 10 days, and that hammer is what got us there.” Citing the bit’s aggressive button structure and air channels, he says, “It is the perfect bit for us because it cleans away from the face so well.”
Jackson used another manufacturer’s hammer in the past, but found rebuilding the Atlas Copco hammers was a better value. “Our other hammers were cheaper, throwaway hammers. Now we work with our distributor, Stockdale Mine Supply, to service the hammers.” Each rig has multiple hammers on site and changes out when necessary. “We don’t mess around with a slow hammer. If it’s slowing down, we change it out and call Randy.”
Randy Neff is Jackson’s Stockdale contact. He says that he put Jackson on a hammer contract for rebuilding hammers. Neff says, “An efficient hammer drills a hole faster, Jackson doesn’t waste time with hammers, and we know what to look for when pulling it apart.”
Jackson also drills 5-inch holes when the rock formation requires it, but not in limestone. For 5-inch work, they use the Atlas Copco Secoroc TD50 hammer.
Cutting back on air also allows them to be more fuel-efficient. “With the 4-inch hammer, you only need 560 cfm; the 5-inch requires 900 cfm. This is production drilling, and it’s all about knowing and managing physical costs,” explains Southward.
For example, the company’s two TH55 drill rigs do not have on-board air, so the crew drills using airpower from an 1,170-cfm, 350-psi auxiliary compressor supplying air to both rigs. Sharing air from one compressor allows them to use less fuel. Each rig drags a hose, drilling five holes before the compressor needs to be pulled forward with a dozer. The newer T3W with Atlas Copco’s electronic air regulation system (EARS) allows the air compressor’s volume and pressure to be dialed back, saving on fuel to supply the necessary air.
Years of experience has given the Jackson crew members a chance to understand where they need to make adjustments and outfit a fleet while being cost conscious. Southward reiterates, “We know what each rig will do. First, it’s about knowing your physical costs. Then it’s all about the production.”