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Mark Zoback in 2010

Mark Zoback in 2010

National Academy of Sciences/Flickr

A geoscientist’s take on new U.S. fracking rules

New federal rules aimed at making a controversial oil and gas drilling technique safer and more transparent reflect numerous suggestions from technical experts, says a geoscientist involved in the process.

Late last month, the U.S. Department of the Interior released new regulations governing the use of hydraulic fracturing techniques, better known as fracking, by oil and gas companies drilling on federal and tribal lands. The rules—updated for the first time in 30 years—apply to 283 million hectares of public land and 23 million hectares of American Indian land. About 90% of new or planned wells on federal land use fracking, officials estimate. Overall, wells on federal and tribal lands produce less than 25% of the country’s oil and gas.

The rules go beyond many, but not all, state regulations by requiring drillers to provide regulators with details about a well’s geological setting and to disclose the substances they inject into the well in order to fracture deep layers of rock (although companies can still request that trade secrets remain private). In a bid to protect ground water and surface waters, the rules also ask companies to explain how they will drill, case and seal the wells properly to prevent leaks (a process known as cementing), and handle wastewater that is pumped back to the surface.

Those ideas were among the many recommendations made in 2011 by a high-level advisory panel created by then–Secretary of Energy Steven Chu to examine whether the United States could develop its natural gas resources while protecting public health and the environment. One member of the panel was Mark Zoback, a professor of geophysics at Stanford University in California. Zoback recently spoke with ScienceInsider about the background and implications of the new rules. This interview has been edited for clarity and brevity.

Q: What is important about these new rules?

A: There are three main recommendations here: One is a full disclosure of the fracturing fluids; another is cementing requirements for each well; and the third has to do with the containment of fluids at the site during the development process.

Q: Let’s start with the disclosure of the fracturing fluids. What was the problem?

A: Companies were not required to reveal the composition of hydraulic fracturing fluids, and there’s been a lot of concern in the public that toxic chemicals were being used and injected into the subsurface. A number of companies have come forward and are disclosing the fracturing fluids voluntarily, but there was not a requirement that the composition of the [fluids] be disclosed. This has caused a lot of suspicion and distrust on the part of the public.

In our 2011 [advisory panel] report, we strongly recommended full disclosure not only of the hydraulic fracking fluids, but of the entire fluid budget associated with drilling and hydraulic fracturing of the well. In other words, where the fluid comes from, its initial composition, how was it used, and then how is it disposed of at the end of the process. Our committee felt very strongly that full disclosure of this information would go a long way to relieving public distrust.

It turns out that the fluids that come back [to the surface] after hydraulic fracturing are of more concern than those used during hydraulic fracturing. Largely, hydraulic fracturing fluids are quite benign. But those fluids that come back are very salty and can contain things like arsenic, selenium, and iron, and sometimes naturally occurring radioactive materials that come from the shale that has been hydraulically fractured. These have to be recycled, that is, used for drilling or hydraulic fracturing in future wells, or they have to be disposed of properly.

Q: What is the benefit of the cementing requirements?

A: The real issue of environmental protection when it comes to drilling is proper well construction. Wells need to be drilled properly, cased properly, and cemented properly. When they are, they can function without environmental impact. [But] when they’re not cemented properly, they can cause contamination whether you’re doing hydraulic fracturing or not.

If we turn the clock back about a year or so, [the] then-administrator of the [Environmental Protection Agency], Lisa Jackson, commented that there are no documented cases in which hydraulic fracturing has caused the contamination of aquifers. And that’s after something approaching 1.5 million or so hydraulic fracturing [operations have] been carried out in the last 10 years.

Now, that doesn’t mean there’s no contamination—there is contamination near some drilling sites. But when people have looked at the source of the contamination, it turns out poorly constructed wells, wells in which the casing and the cement were not done properly, were the cause. So what the Department of the Interior is asking for here are additional safeguards to make sure that well construction in each and every case is done as well as possible. So again they’re addressing the core issue and it’s important that this be done.

Q: What are the consequences of a poorly constructed well?

A: A dramatic example is the [2010] Deepwater Horizon accident [which caused a massive oil spill in the Gulf of Mexico]. In that case, the well was not cemented properly and that caused the blowout.

[In oil and gas wells], you have a buoyant fluid, and that buoyant fluid wants to move upward. You want that fluid to move upward inside the steel casing, but if steel casing is not properly cemented, oil and gas can move on the outside [of the casing and] cause problems.

Q: What about the fluid containment rules?

A: That’s really about [limiting] what [are] called fugitive emissions. When [the injected water during hydraulic fracturing comes back to the surface], there might be small amounts of natural gas in that water. If you put [it] into a tank, you can contain the gas and other volatile organic compounds and deal with them properly. If you just put [the water] into a pit, [the compounds] can escape into the air.

You want to limit those emissions for two reasons. At the local scale, you want to limit the air pollution that might be caused during the drilling operation. At the more global scale, you want to limit methane emissions into the atmosphere. Methane’s a very potent greenhouse gas, so you want to contain the emissions as best you can.

Q: Companies will now have to submit a geologic assessment of a drill site to federal regulators. Why is that information valuable?

A: The drilling plan proposed in a permit has to reflect the geologic conditions at that site … the proposed drilling and well construction needs [to be] married to a geologic assessment. They’re asking what the geology is, and what steps do you plan to take to protect near-surface-water supplies from potential contamination during the drilling and well completion process.