Squeezing the Shale: Hydraulic fracturing releases the oil in this boom

Hydraulic fracturing has been a means of retrieving oil and natural gas for more than 50 years, and with technologies and methods improving, it has become a regular practice to tap into oil and gas previously unrecoverable.
Hydraulic fracturing, or fracking, is the process of injecting fluids under pressure into the earth through a wellbore, or the hole drilled to assist in the exploration and recovery of natural gas, said Scott Tinker, state geologist and director of the Bureau of Economic Geology at the University of Texas in Austin.
Those fluids, under pressure, crack the rock and create fractures or cracks in the rock to allow the oil and natural gas to flow into the hole, Tinker explained.
According to the Environmental Protection Agency website, the fluid commonly consists of water, material to keep the cracks open and chemical additives that open and enlarge the fractures.
Wells may be drilled vertically hundreds to thousands of feet below the surface and may include horizontal or directional sections extending thousands of feet, the website states.
“You can’t produce from shale without cracking the rock,” Tinker said.
Shale is too tight. It doesn’t have enough pores for natural gas to flow out, unless it’s cracked, he said.
The fractures can extend several hundred feet away from the hole, and the materials — sand, ceramic pellets or other small, incompressible particles — hold open the newly created cracks in the formation.
Once the particles are injected, the rock formation’s internal pressure forces fluid through the wellbore.This fluid is stored on site in tanks or pits before it’s treated to remove the injected chemicals and other naturally occuring waste products.
Jack Waldrep, director of the Texas Association of Landmen, said the reason for the popularity of fracking is simple.
For something to be retrievable, he said, it has to be permeable. That’s why people frack.
Some sands and limestones are permeable and porous, he said, and when drilled into, the oil will flow.
“That enhances the production,” he explained. “It gives the company the ability to retrieve more oil out of those zones down deep. Basically, what fracking is, is it breaks up that rock. They can frack and inject sand into that zone to hold fractures apart to where you can retrieve oil and natural gas.”
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