Ceramics challenge sand in fracking Utica shale wells
Gas companies exploring potentially high-producing wells in the deep Utica shale while prices remain at multiyear lows face a $2 million question: sand or ceramic?
Hydraulic fracturing requires mixing what engineers call a proppant with the water they pump into the well to prop open the cracks created in the shale and release the natural gas or oil it holds.
A mile or so under the surface of Pennsylvania, West Virginia and Ohio in the Marcellus shale, natural sand or grains coated in resin generally will do the trick. But the increased heat and pressure of the Utica — which in some places is twice as deep as the Marcellus but believed by some to hold more gas — are sometimes too much for sand to handle, prompting some companies to use a more expensive proppant made from ceramic.
“The deeper you get, the higher stress you get. There's that much more rock on top to crush your sand,” said Kirby Walker, director of regional operations for Cecil-based producer Consol Energy, which is exploring Utica wells as deep as 13,000 feet.
Consol was the first to use a new high-tech ceramic proppant from Houston-based Carbo Ceramics Inc. in the GH9 Utica well it recently completed in Greene County. It is testing mixes of other ceramics in Utica wells in Ohio.
The ceramic particles are stronger and perfectly round, allowing more gas to move around them than irregularly shaped sand grains, advocates say.
“In my opinion ... if you use a ceramic, it's always going to produce more,” said Terry Palisch, global engineering adviser in Dallas for Carbo. “The question is: Is it enough to pay for that increase?”
Ceramics cost at least four times as much as sand, though the prices are coming down a little. David Elkin, senior vice president for drilling and completions at Downtown-based producer EQT, put the additional cost at $2 million to $3 million.
EQT used ceramics in its Scotts Run Utica well in Greene County, but switched back to sand for its nearby Pettit well in the Utica and expects to stay with sand for others.
“We've made a decision that it's not worth the additional cost,” Elkin said, noting tests showed no major effects for the switch.
Like all producers making a push into the Utica, EQT is trying to reduce the cost of tapping the deeper rock, which can produce much more gas than a Marcellus well but at twice the price.
Choosing which proppant to use requires weighing the cost against benefits that ceramics can bring.
If the high pressure of a deep well crushes sand, the grains will pulverize, blocking fractures and reducing gas output, Walker noted. The size and density of ceramics can be more tightly and consistently produced than natural sand, giving engineers more control over what they're sending in the shale fractures.
“Anything you can do to make it flow more easily around the proppant will help production,” said Palisch, whose company sells proppants in different sizes and densities.
The amount of sand drillers are sending into a well has doubled with longer lines. Less proppant is required when using ceramics, Palisch said.
Ceramics also don't produce silica dust, which can be harmful if workers breathe it. The federal government is expected to tighten regulations soon on silica dust at workplaces.
Consol is monitoring results from wells for several more months to determine which proppant or blend works best at which depth.
If and when gas prices improve and companies such as Consol further explore the Utica, they will want to have test data in hand on factors including proppant to ramp up production quickly.
“Ceramic is the way to go if you take price out of it,” Walker said.
David Conti is the assistant business editor for the Tribune-Review. Reach him at 412-388-5802 or firstname.lastname@example.org.