Balancing act needed to win with hydraulic fracturing

JIM WELLS COUNTY, Texas – On a September morning near the line where Jim Wells and Duval counties meet, truck tracks mark the path to a new oil well like chicken scratch.

More than a mile below the surface, ancient rock starts cracking.

San Antonio-based Inland Ocean’s new well has drilled into a tight rock formation, which must be fractured before oil will flow — a process common across South Texas with the Eagle Ford Shale oil boom.

The site is crowded with pumper trucks, cranes, sand trucks, tanks, a mixer and about a dozen pickup trucks. Around 6,000 barrels of water — 252,000 gallons — has been delivered. Recently cleared brush and oil field pipe pile up to the side.

Hydraulic fracturing pumps a mix of water and chemicals at high pressure to break the rock. Sand is added to the fluid in increasing amounts to hold open the rock fissures, letting oil and gas flow up the well to the surface.

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At the center of the bustle is the Christmas tree — the valves, spools and fittings at the top of the well. It controls production, and attached to the top of it is the “frac tree” or “frac stack,” which lets the pipes at the surface feed the fluids down the well.

Inside the command center — a rolling high-tech office pulled by a tractor-trailer — screens show an array of measures, including a red line that climbs a chart.

“The pressure line is telling a story,” fracturing engineer Paul Aleman says.

Seeking just right

The momentum of fracturing keeps everything in balance. Pump too slow and the sand will “screen out,” plugging the well and making a mess down hole. Pump too fast and the fluid could “leak off” into the earth, and the spears of the cracks will close, the fluid disappearing into the formation.

So far, they’ve been testing to make sure the fluid can be pumped and sustained at the rate calculated for this well.

“You can’t afford to hurry and do it wrong, and then have to go back and redo it,” says Hans Helland, a second-generation oilman and the operator of the well. The first stage of this frac will cost around $125,000.

Even during testing, the fluid breaks rock in the 400-foot-thick formation. As long as there’s pressure from the army of pumps above, the fissures keep growing.

Now they need to keep them open. Aleman says it’s time.

“Let’s get some sand in the ground,” says Russell Musgrove, who works with the Tuleta-based engineering company that’s overseeing the drilling and completion of this well for Helland.

The racket of the engines grows from loud to deafening.

Hydraulic fracturing is not a homogeneous process. Every well requires its own design.

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The operator of the well can offer up drilling logs and core samples of rock formations taken during drilling. The operator’s engineers and geologists weigh in, but Musgrove says that in large part well owners rely on expertise of service companies, in this case Halliburton, to design the frac.

“We rely on the fracking companies because they do it all over the place on a consistent basis,” Musgrove says.

They pump at a rate of 25 barrels of fluid per minute, or 1,050 gallons.

Every 20 minutes the contents of a frac tank disappear underground, about 500 barrels.

Sand moves into the formation, first at 1 pound per gallon of fluid. Then at 8 pounds per gallon.

Right consistency vital

As the hours wear on, engineers periodically check the fracturing gel to make sure it’s the right density and consistency. The fluid travels down thousands of feet under ever-increasing pressures and temperatures. If the sand starts to fall out of the liquid before it gets into the rock formation, pressure will build at the surface, and they’ll have to shut down. The goal is to push the sand into the farthest part of the formation and build backward.

At the highest point, the pressure reaches nearly 4,700 pounds per square inch.

By around 3:20 p.m., the engineers and supervisors talk into their headsets.

“Bring it down.”

“Shut it down.”

The mechanical racket starts to dull, and small smiles break out in the control center.

“It makes my day so much better when the first stage goes good,” Musgrove says. He’s mostly been working Eagle Ford wells in Gonzales County. “Every area has different challenges. I have to change my way of thinking for every well.”

The first stage of this fracturing job is done, and it went smoothly.

Many fracturing operations run 24-7, with lights and cranes glowing at night and have as many as 25 stages. This is a two-stage job, so it’s daytime only.

The crew unwinds its way out of the hole, which has swallowed around 120,000 gallons of fluid and 250,000 pounds of sand in its first stage.

They’ll return in the morning, when they’ll perforate the well higher up in the formation and begin again.

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