Take it from the ‘top’

August 29th, 2013 | Posted by in TH60 | Waterwell Drills

Apex Drilling’s TH60 grants greater accessibility, punches 8,200 feet in first six weeks

After five years working as a geologist and wireline engineer overseas as far away as Indonesia, Mike Becker set his sights on Hill Country in Central Texas.

“There’s a lot going on here geologically with seven to eight major and minor aquifers.” He explained the Llano Uplift, the pre-Cambrian granite in the western portion of Texas Hill Country, describing the mathematical wizardry of hydrologists here, who do drawdown testing and complex formulas for each water district to determine the ultimate impact on the underlying aquifers.

In 1999 Becker established Apex Drilling, a water well specialist and pump service, 45 miles northwest of Austin in Marble Falls. A Texas Tech graduate with an oil field background, Becker chose the name Apex (the top or peak), which represented the expectations he had for his water well business. Andrew Johnson has been with him since the beginning as driller and pump installer. Andy’s brother Robert joined them shortly after and now runs the pump services side of the company. In those first years, Becker said, they worked from dawn to dusk. “Central Texas was just booming in 1999,” Becker said.

One of their first rigs was an Ingersoll Rand T4. Since then they have only had to make a couple of rig choices to dial in which rig works best for their operations. In 2004 they traded in the T4 for a 1999 T3W. “The T4 was just too big for us, both regarding jobsite access and in the cost of running it. The T3W was much more economical.”

In February 2013 Apex Drilling traded the T3W in with 9,980 hours on it for an Atlas Copco TH60 packaged with all the options from Venture Drilling in Georgetown, Texas, an authorized Atlas Copco distributor serving a seven-state area from three locations. Johnson said it took a little getting used to for him, but he really likes the rig. Double-checking his logs, he said in the first six weeks they had drilled 28 wells with it, logging 8,200 drill feet.

Johnson explained the differences: “The engine is much quieter. It just has one. And everything is electronic. There are so many more solenoids, valves. It took some getting used to, but I actually like it better. It’s easier to run and easier to drive on the highway.”

Johnson added, “It has more power.” The TH60 engine generates up to 600 hp (477 kW) and is rated for 40,000 pounds pullback with a 18,000-pound single line winch.

“And the feed rate is just the opposite from the T3W,” Johnson said. “On the T3W, it’s faster down. The TH60 is faster up.”

Atlas Copco had inverted the cylinder so the larger side of the piston would be used for pullback force. The cylinder now applies more pullback force with the same hydraulic pressure as before. By increasing hydraulic pump flow to the cylinders, the TH60 maximum fast-feed speed is now up to 150 feet per minute (45.5 m/min.).

Johnson also noted the T3W rig’s weight was greater because of its extra engine. “In some places, we just weren’t able to gain access as easily as we can with the TH60. And I think we just couldn’t do before what we can do now.”

Crystal Mountain

On this day Johnson was on site at a new home being built in Crystal Mountain, a residential subdivision of Round Mountain, which is 35 miles west of Austin. The water below is in the vast karst system of the Ellenburger Formation, which dips southeast toward Austin. The karst was formed from carbonate deposits that built up during the Ordovician period more than 440 million years ago, back when Texas was a shallow water ocean and the equator ran across Northern Canada.

Texas regulations require water wells to be cemented for the first 10 feet of an 8-inch hole, which Apex would generally continue from with a 6.5-inch drag bit in gray/white limestone. However this water district calls for additional grouting to 50 feet. Apex then continued to 100 feet with the drag bit, switching at that point to a 6-inch Atlas Copco Secoroc QL 60 hammer with Atlas Copco 6.125-inch concave spherical button bit.

The water here is found in fractures within the dolomitic limestone. “Hit a fracture, there’s water,” Johnson said. “I’ll hit several of them. I log them so when we set casing, I know where the best place to put the screen is.”

Apex Drilling drilled 8,200 feet in the first six weeks with their new Atlas Copco TH60.

Johnson was finding the first fracture between 172 and 190 feet (52 to 58 m). That first fracture at this jobsite was producing only about 2 to 2.5 gpm. As he encountered it, the drill string stuttered for a couple of revolutions. “It really grabs at the bit,” he said.

Johnson was adding water at a half gallon a minute. “You have to add the water. There’s a dry, silty clay that likes to blow up in a big cloud of dust. So we keep it wet the whole way. Plus it helps to keep the hammer and bit cool.”

Johnson kept his eye on the cuttings, pointing to the discharge as it turned pink. Tan chips were okay, too, but Apex had learned to associate pink cuttings here with the highest water quantity.

Johnson continued on to 400 feet total depth. As the hole was being cased to the bottom with 20-foot lengths of 5-inch OD (4.5 ID) PVC, he set the factory-slotted PVC SDR17 screen at around 300 feet where a fracture was producing up to 17 gallons per minute. Becker said they’d seen bores in this formation produce anywhere from 3 to 60 gpm.

Becker said they average 200 to 250 wells a year, with most of their upcoming jobs between Austin and San Antonio. Apex at times goes as far as 150 miles in its range, but generally jobs are within an 80-mile radius. Since drilling its first wells at Crystal Mountain, Apex has already completed 50 or so for the community, with 20 more to do this year.

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