When petroleum innovator George Mitchell figured a way to get oil and gas from impervious shale formations in the 1980s, he gave new life to the fading fossil fuel industry.
Shale is a fine-grained sedimentary rock formed when silt and mud are compacted. Most geologists call this kind of rock mudstones, but shale is different because it’s made up of a lot of thin layers and easily splits into thin pieces along those layers.
Black shales sometimes contain organic material resulting in natural gas or oil.
But the key is getting the natural gas or oil out of the shale.
Mitchell’s method may have opened a way to energy independence for the United States by allowing oil companies to exploit this black shale.
Recently, petroleum companies have begun exploring a level of geologic rock in the Permian Basin, known as Cline Shale. Even Laredo Petroleum Inc. chairman and chief executive officer Randy Foutch has called the Cline shale “world-class,” according to Nissa Darbonne, editor –at-large of the Unconventional Oil & Gas Center.
At a meeting of producers in New York in April, Foutch admitted the Cline is relatively less familiar to many in the business, but Laredo has made it a point to study.
The Cline is Pennsylvania age – about 325 to 286 million years ago. Foutch said the Cline is located beneath the Wolfcamp, a Permian era deposit. It’s located about 80 miles across the Midland Basin in West Texas.
Some geologists have contended Foutch is in era and say the Cline is part of the Wolfcamp. Neverthe less, the local name being used by many landmen and energy company experts is “Cline.”
Using Mitchell’s version of fracturing, the Cline Shale has become one of the hottest topics among energy companies and investors.
Keith Schaefer writes a blog about investing in oil and gas. In late April, he reported Devon Energy is looking hard at the Cline. In fact, Schaefer said, “The Cline Shale in Texas is one of the hottest new shale plays in the USA.”
But the key, Schaefer writes, is the ability to reach these formations deep under the earth.
How much oil might be in the Cline Shale that runs through West Texas?
Shaefer: “Devon gave a ‘type curve’ for a Cline shale well – a guess at how much the well would produce over time – of total production 570,000 barrels of oil equivalent – and 85 percent of that would be oil and liquid rich gas. .. The well would flow an average 600 boe/d (barrels of equipvalent per day) for the first month … and cost $6.5 million.”
A barrel of oil equivalent is based on the approximate energy released by burning a barrel of crude oil. A barrel is about 42 gallons.
That’s where Mitchell’s fracturing comes in.
Natural gas, along with varying amounts of oil, he learned, could be made to flow to a well by fracturing the shale formation with water and propping the fissures open with sand — hard sand, not the sand that comes from the Sahara Desert or blows across the West Texas terrain.
According to Mohamed Soliman, chairman of the Petroleum Engineering Department at Texas Tech, sand from the United States would be imported by Middle East producers in the event they needed to fracture a well.
A hard sand, he said, comes from an area near the Texas town of Brady.
Other propping materials being used include glass beads and hard plastic.
Tye Terry, general manager of the service company Texas Specialty Sands, said his company will provide high-grade sand from Central Wisconsin for use by Permian Basin operators.
Davis L. Ford, consulting environmental engineer and board member of Clayton Williams Energy, said in an interview alongside Soliman at Tech, that fracturing formations was actually done in the late 1940s, but Mitchell refined it in the late 1980s.
“George Mitchell started in the Barnett shale, using new technology.
It was George Mitchell who really made hydraulic fracturing the thing of the future — right here in Texas.”
According to Soliman, horizontal drilling — a method of curving a drill string into a lateral direction — took off in the late 1980s.
“Immediately people started looking at fracturing, but people still were applying it to sandstone. Nobody was applying it to shale.
“And that is where George Mitchell really made the difference, because he went into the Barnett shale. And he said, ‘hey, I can fracture this,’” Soliman explained.
“People used to look at shale as something to avoid.”
Ford agreed: “That’s right — you couldn’t do it. It would be called a dry hole.”
Now, the service companies are busy with the fracturing of shale formations, according to Ford.
“Today, if you want something fractured, you have to wait in line.”
Can the activity of today be called an oil boom?
“It’s a gas boom,” Soliman said.
Ford said, “I would call it an energy boom.”
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