Expert: Gas drilling about risks vs. rewards

http://citizensvoice.com/news/expert-gas-drilling-about-risks-vs-rewards-1.1078631

Expert: Gas drilling about risks vs. rewards

By Elizabeth Skrapits (Staff Writer)
Published: December 17, 2010

NANTICOKE – Natural gas drilling comes with risks to the environment and human health, and the issue is to determine whether those risks are worth the potential rewards.

Dr. Anthony Ingraffea, a professor at Cornell University’s School of Civil and Environmental Engineering, talked about what can go wrong with natural gas drilling and dispelled some myths about the process during a lecture Thursday at Luzerne County Community College.

“No industrial activity, even building a toaster, is risk-free,” he said.

Ingraffea stressed the importance of calculating the level of risk: taking the probability of things going wrong and weighing them against the expenses, costs and benefits.

The Marcellus Shale, which lies beneath much of New York and Pennsylvania, is rich in natural gas. However, it was not considered economically viable until four new technologies were developed, Ingraffea said.

These are directional drilling – going horizontal to access the thin layer of shale – high volumes of hydraulic fracturing fluid, using slick water to control the amount of power needed to pump large volumes of the fluid at high pressure quickly over long distances, and drilling multiple-wells on a single pad to access as much of the gas as possible in a particular area so as to require a minimum of leasing and capital expenditures.

Hydraulic fracturing or “fracking” involves blasting thousands to millions of gallons of water containing chemicals and sand thousands of feet underground. This re-opens fractures in the shale, where the natural gas collects. Ingraffea pointed out that the gas is not in the rock itself, but in its natural fractures or joints.

Part of the water used in fracking comes back laden with chemicals, naturally occurring radioactive material, heavy metals and salt. This flowback water has to be disposed of, he said.

Although hydraulic fracturing was around since 1947, the four technologies are relatively recent, Ingraffea said. The first hydraulically fractured well in the Marcellus Shale was drilled in Washington County in 2003, he said.

Slick-water, high-volume fracking has a higher risk to the environment and human health for reasons including that it requires much more industrial development over large areas with heavy equipment operating constantly, and it produces much higher volumes of wastewater.

As the number of wells and the volume of wastewater increases, “odds go up that bad things will happen,” Ingraffea said. These range from blowouts to leaking wastewater trucks.

Research hasn’t been done on the cumulative effects of natural gas drilling, he said. In Pennsylvania – New York has a moratorium on drilling – gas companies are only a few years into what could be a 30- or 40-year development.

And the problems with natural gas drilling, such as methane migration and frack fluid migration, are not new: the industry has known about them for 25 years, Ingraffea said. They are being solved – but they’re not solved yet, he said.

There is no way to guarantee the cement casing, which is poured around metal pipes in the well as a layer of protection, will be perfect, Ingraffea said. The casing can corrode or burst, for example.

The natural gas industry does not have complete control over the wells: they are working thousands of feet underground, where they can’t hear or see, and they rely on imperfect computer models, he said.

Ingraffea said he thought the current rate of natural gas well accidents is too large. If, as predicted, there will be 400,000 Marcellus Shale wells drilled over a 50-year period, how many major failures are acceptable? he asked.

“We’re already at one for every 150 wells. That’s 98.5 percent reliability,” Ingraffea said.

“You’ve got to make the call. What’s an acceptable level of risk?” he continued. To do that, you’ve got to see the quantification of the things that can go wrong. We’re just now beginning in Pennsylvania to be able to quantify the number of accidents per well, or the number of accidents per truck trip, or the number of accidents per million gallons of frack fluid. That stuff could have been modeled. You don’t have to wait for your experience to learn these things. They could be predicted.”