Well Field Puts Growth On Track in Central Utah
Large Diameter Wells Pump 6,000 GPM in Arid Area
Drillers know they make an impact, but that doesn’t usually mean helping to supply water for hundreds of thousands of people. Steven Bryan sensed the scope of the Central Utah Water Conservancy District project when he got the call. Working the project, which involves several 24-inch wells that will supply a swath of central Utah, only confirmed the impact.
“In my 35 years of drilling, this is the biggest project I’ve ever been involved with,” said Bryan, who is rig manager on the project. “It’s the future of water resources in this area.”
The CUWCD accepted the bid in 2011 from Hydro Resources out of Fort Lupton, Colo., for the project on the former site of Geneva Steel Mill in Vineyard, Utah, not far north on Interstate 15 from Provo. The original scope, as envisioned by primary engineers at Hansen, Allen & Luce, involved 14 large-diameter wells estimated to pump 3,500 gpm. Drillers wrapped up the fifth well in October, and production on each nearly doubled that early estimate.
“In all instances, the wells have exceeded our design estimate in terms of production,” said KC Shaw, a project manager with CUWCD. In fact, each well is good for about 6,000 gpm.
“There’s probably not many wells anywhere to compare to the amount of water these wells produce,” Bryan adds. “Anybody would die, especially in the desert, for that kind of water.”
That water will pump through a series of aqueducts to supply taps across central Utah.
“They have a whole new source of drinking water,” Bryan said. Residents will no longer solely rely on the whims of the arid western climate and water access won’t constrain growth in the area.
Getting the Job Done
“These are probably some of the deepest wells in all of Utah that furnish culinary water,” Shaw said.
To get the job done, Hydro used Challenger 320 flooded-reverse rigs. That method helped with both the depth and diameter of the bores, and with the makeup of the valley floor jobsite. Drillers found unconsolidated materials like sand and large cobble, interspersed with layers of clay, on their way down to between 1,500 and 1,630 feet. In addition, they had to case through several other aquifers.
“We have really three aquifers that we’re dealing with,” Shaw said. “They’re under, in many instances, artesian pressure, so as we’re going through, the bit program has been a real challenge and I think Hydro has just done a fantastic job in learning from that, and does a great job in managing their bit program and their mud program.”
The mud and bit programs both evolved.
“In the beginning of the project, we were using a mill tooth bit,” Bryan said. “It’s designed for medium formations, clays, and gravel and stuff like that. This stuff was so coarse, and it was so ununiform, that it just ate the mill tooth bits up.”
He added that the mill tooth bits lasted about 400 feet chewing through materials at the Geneva site. As the project progressed, Hydro switched to long-toothed, carbide-tipped butt bits, which lasted for several thousand feet, rather than 400. Bryan adds that the butt bits even gnawed through the clays. “These clays were very accommodating to a butt bit, as long as it was a long-tooth.”
Hydro crews cased through a shallow, confined artesian aquifer from about 80 to 240 feet bgs. Getting that right was critical, Shaw said, because many local agricultural wells tap that aquifer. Then, drillers cased through two deeper aquifers: from 330 to 450 feet, and from about 600 to 1,100 feet. Clay confined both of those, too.
“Then we continued to drill,” Shaw said. “We wanted to see what was deeper, and we did find a ‘basement aquifer’ that’s down 1,400, and we’ve drilled to 1,600.”
“The first couple wells were pretty challenging. It took a long time because of the cobbles that were being drilled up, and then going into clay, and then keeping the hole open. The very first well we drilled, we lost, I don’t know, four or five collars and a drill bit downhole and had to fish those out. We learned a lot from that about how to keep the hole open and the mud program.”
Even with lessons from the first well, Bryan says others still challenged the Hydro team.
“The thing about these wells, is everywhere you drilled it was a different formation. ... You had to adjust on every one of the wells that we drilled because none of them were exactly the same.”
For each well, Hydro drilled 45-inch holes to about 300 feet to set 36-inch casing, then drilled a 32-inch hole to the target depth for a 24-inch casing. Wells in the Geneva field sat about 1,500 feet apart, Bryan said.
Bryan describes a fluids balancing act over the course of each bore.
“You have to have a perfect balance of your drilling mud because, if it’s not heavy enough, in the artesian formations, then the pressures overcome the fluids you have in the hole and the next thing you know you have a flowing well. That’s not good while you’re drilling. If it’s too heavy—your drilling fluids are too heavy—then you become overbalanced and it’ll go out into the formation, causing lost circulation when there’s really not a loss of circulation so much as a the fact that your fluids are too heavy sitting in the hole.
“Having a perfect balance of drilling fluids in these types of formations is critical for the stabilization of the borehole.”
Yet, originally the project barred the use of lost circulation materials (LCMs), complicating the work of drillers on site. In fact, Utah regulations for well drillers state “Organic substances shall not be introduced into the well or borehole during drilling or construction.” That means no sawdust, hulls or similar LCMs. The state only allows bentonites and synthetic polymers that can be flushed or developed out.
“We were reluctant to allow use of LCM in the drilling because our experience, and our consultant’s experience, has been that that’s a difficult thing to be able to get out,” Shaw said. “But the zones were so porous that it was very challenging to drill through those without the use of LCM.”
Difficulties early on changed minds. “At the beginning, the client didn’t want us to use any LCM, but after we pumped about a quarter million dollars worth of mud into one of the holes we said, ‘this is ridiculous.’”
The CUWCD worked with Hydro to develop a fluids program that allowed acid wool down hole, but minimized its use by allowing it only when drillers hit porous zones that required stabilization.
Shaw added that a program was developed to dissolve the acid wool material, so it wasn’t left in the boreholes to plug up the formation or turn up in drinking water.
Bryan said he was told the deepest of the wells, at just over 1,630 feet, hit a new state record for depth on a 24-inch well. That well uses a Roscoe Moss louvered screen, which Hydro used on three of the five wells drilled so far. The other two wells used wire-wrapped screens from Johnson Screens. In fact, Bryan said Johnson told him one of those custom screens was the largest the company had working in a production well.
“Johnson, from what I understand, actually had to build a machine to wire wrap these screens because they’re so big,” he said. “This 24-inch well, according to Johnson, is the largest wire-wrapped screen in the world.”
Beyond the well field, the $325 million project also includes miles of pipeline with daily flow rates ranging from 21,050 gpm (for narrower portions of the aqueduct) to 56,700 (for the larger-diameter parts), a 40-million gallon reservoir, water treatment upgrades, pump station and well houses.
“I am not aware of any other project that matches this one in overall scope,” said David E. Hansen of Midvale, Utah-based Hansen, Allen & Luce, the project’s principal engineer. “This is the largest single groundwater development project ever undertaken in the state.”
History and Future
The High Head Wells project that Hydro is working in sits on the former site of the Geneva Steel Mill. The mill opened in the 1940s but closed permanently in 2002 after a couple bankruptcies.
The CUWCD, in 2005, bought 45,000 acre-feet of water rights from the company in liquidation for $88.5 million. Those rights, combined with previously purchased rights, formed the basis of this project. The Geneva water rights came with almost two dozen existing wells ranging from 160 to 1,300 feet. Those wells underwent geophysical analysis and video logging.
“In the end, (we) determined that we couldn’t rehab them; we had to plug them all and then drill new wells,” Shaw said. “But, it did provide us with a wealth of information about what to expect. … We felt very confident in—not only the water quality—but the water quantity and availability after doing all that work.”
“The recharge rates have been studied,” Shaw adds. “We’re still confident that we’re not mining water, that there’s sufficient recharge to continue to supply this aquifer.”
For his part, Bryan just revels in a challenging, rewarding job well done.
“This has been the best project I’ve ever worked on,” he said. “And I don’t imagine I’ll work on another one quite as good again. Hopefully, I will, but it’s just been huge. It’s been a great success for everybody.”