Colorado’s biggest oil and natural-gas producers are experimenting with a new drilling technology billed as cheaper, faster and quieter than conventional drilling.
The promising drilling technique is not yet a panacea. So-called coiled tube drilling rigs have limits on the depths they can reach and the geologic formations they can breach.
Yet some energy professionals say the new rigs could one day fundamentally change the process of exploiting Rocky Mountain natural gas.
“Coiled tube drilling could be quite revolutionary,” said Jim Myers, a Denver-based drilling engineer for energy giant EnCana Corp. of Calgary.
In government-sponsored tests that combined coiled tube rigs with another technology, small-diameter or “microhole” drilling, costs have been reduced by 38 percent.
If similar savings can be achieved in commercial drilling, the average $600,000 cost to drill a gas well in eastern Colorado’s Wattenberg field could be reduced by more than $200,000.
The lower costs are achieved by shaving up to two days off the time needed to drill a well, compared with the typical six days or more needed to drill in Colorado with the larger and more cumbersome rotary drilling rigs that are standard in the industry.
Unlike the rotary rigs that operate by stuffing dozens of 30-foot sections of steel pipe atop one another into the ground, coiled tube rigs – as their name suggests – operate by using a continuous strand of tubing with an embedded drill bit, eliminating the need to stop every 30 feet to screw in a new piece of pipe.
The newer rigs are smaller and more portable than standard rigs. The smallest can be placed on a trailer towed by a pickup truck. Even the larger ones being tested in Colorado can be disassembled and moved on about a dozen semitrailer loads, compared with the 20 to 30 trailer loads for a rotary rig.
EnCana has used the rigs successfully in Canada and is beginning to test the units for drilling natural-gas wells in the Piceance Basin of western Colorado.
Another major producer, Anadarko Petroleum, began using a coiled tube rig in November in the Wattenberg oil and gas field.
While the handful of wells drilled by the rig haven’t yet yielded enough data for Anadarko to provide operational statistics, the energy company is confident enough in the performance that it will bring one or two more coiled tube units to Colorado this year.
“We can’t quantify the benefits yet,” said Bart Boudreaux, general manager of Rockies drilling for Anadarko. “But the beauty of this is that if we can drill wells faster, we can reduce our costs and drill more wells.”
The technology got a thumbs up after the National Energy Technology Laboratory, in conjunction with Yuma-based Advanced Drilling Technology and Rosewood Resources of Dallas, drilled 25 small-bore wells with coiled tube rigs in the Niobrara gas formation of eastern Colorado and western Kansas.
The 3,000-foot-deep wells – shallower than most others in Colorado – were drilled in as little as 19 hours.
“You can get these wells drilled in record time, and that’s where the economic benefits come in,” said Roy Long, a Tulsa, Okla.-based official of the federal energy laboratory.
Oil and gas producers now are working to make coiled tube rigs functional for wells as deep as 14,000 feet, a depth sometimes encountered in western Colorado and Wyoming.
“It’s a promising technology,” said Brian Macke, director of the Colorado Oil and Gas Conservation Commission. “It reduces the drilling time and reduces the impact on nearby residents.”
Staff writer Steve Raabe can be reached at 303-954-1948 or sraabe@denverpost.com.
