By SEAN COCKERHAM
WASHINGTON -- The U.S. fracking boom is getting even bigger with advances in drilling techniques that are making oil and natural gas wells more productive.
Each drilling rig in the Eagle Ford shale of south Texas is pumping an average of more than 400 barrels a day than in the dawn of the fracking boom seven years ago, according to the federal Energy Information Administration.
The more efficient drilling has helped Texas to more than double its oil production in the past three years, topping 3 million barrels a day for the first time since the late 1970s.
"The productivity of oil and natural gas wells is steadily increasing in many basins across the United States," federal energy analysts said in a research memo.
The United States has surpassed Saudi Arabia and Russia to become the world's biggest oil producer, with Texas and North Dakota accounting for more than half of American drilling.
The U.S. also is now the world's biggest producer of natural gas. This American energy boom is because of hydraulic fracturing, known as fracking, in which massive amounts of high pressure water with chemicals are pumped underground to break shale rock and release the oil and natural gas trapped inside.
Drillers have honed their fracking techniques since the start of the energy boom and are now getting far more oil and gas from each rig.
Five of the six main shale areas in the United States have seen increased production per rig in the last few years, with Eagle Ford leading the efficiency increase in oil drilling and the Marcellus shale of Pennsylvania tops for natural gas.
The number of rigs in the Eagle Ford has actually dropped in the past two years, and wells decline in productivity by some 70 percent after the first year.
But total oil production in the area has still skyrocketed with increasingly sophisticated drilling techniques.
"Since mid-2013 the gains have really been from getting more out of each well," EIA analyst Sam Gorgen said in an interview.
One new technique is a big increase in the amount of sand used to prop open the tiny cracks created when the chemical-spiked water fractures the shale rock. That appears to boost the initial production rates, according to the EIA, although it tends to be followed by a quicker decline in the well than otherwise.
Another method being adopted by drillers is to use geologic data to pinpoint the best spots along the horizontal well to frack.
"So rather than spacing them evenly across the five or ten thousand feet of well, they are going in and figuring out where is the best place to put their money along the well bore," Gorgen said.
The new techniques are more expensive but worth it to the drillers because they can make money faster, he said.
The growth in the drilling boom has environmental downsides, with complaints about industrial sand mining and the huge amounts of water used in fracking. Fracking wastewater disposal wells have been linked to earthquakes, and university researchers last month found drinking water contamination from badly constructed natural gas wells.
It's also not clear whether the more efficient drilling techniques are going to mean more total oil and gas pumped from each well, or just make the wells run dry faster.
"The engineering isn't certain because we don't have any wells that are 20 years old yet, and few that are even five years old yet," Gorgen said. "So it's hard to say what the long term effect is going to be."