This fall, Yale professor of hydrology Jim Saiers initiates the first scientific study to utilize a network of monitor wells strategically placed to isolate potential shale gas effects before, during and after hydraulic fracturing occurs.
The project design is innovative in its simplicity, says Saiers, and made possible by cooperation of a gas shale development company that is allowing him to install wells and begin sampling in anticipation of drilling. The new study is seeded by a research grant from the Yale Climate and Energy Institute, and other corporate partners.
Half a decade into the “golden age of gas,” Americans enjoy record low prices of the resource, but remain strongly divided over the technology that makes those prices possible. Hydraulic fracturing involves injection of fluids at high pressure to shatter and increase permeability of large volumes of subsurface hydrocarbon-rich rock. While producing vast quantities of gas and oil, the process consumes enormous volumes of water, and potentially mobilizes hydrocarbons, metals and other minerals that can be toxic, and have been known to contaminate drinking water sources. A 2012 survey by the Yale Project for Climate Change Communication and the George Mason University Center for Climate Change Communication determined that people who had developed opinions on “fracking” were almost equally split on the topic, and equally strong in their beliefs.
Ever since the 2010 movie “Gasland” elevated awareness of fracking beyond the places it was occurring, water quality impacts and escape of methane have been two of the most compelling issues for its opponents. While New York State has essentially banned the practice, over 6000 wells have been drilled in neighboring Pennsylvania. There, regulations oblige drilling companies to test water quality in all drinking water wells within ½ a mile of future fracking operations. Deterioration in water quality post-fracking is inferred to be a direct result of the operation and the responsibility of the industry to correct. But despite numerous studies – including a highly regarded one by Duke University – no one has systematically sampled the length of a production zone before and after, to see the impacts of fracking in space and time.
Until now, that is. In a few weeks, Saiers – who’s based at the Yale School of Forestry and Environmental Studies – begins installing strings of monitoring wells at depths of 500’ along the mile-long trajectories of horizontal gas wells to be drilled 5,000 feet deeper down, at a new production site in Northeast Pennsylvania.
Designing a monitoring network with knowledge of a company drilling plan allows for a rare symmetry in the experimental design that will hopefully be reflected in uncommonly robust data. The wells are designed to sample at five depths, measuring pressure changes as fracturing begins and ends, and continuously sampling weekly from the moment they go into the ground. The constituents they’ll be looking for are methane and other hydrocarbons, as well as metals such as lithium and strontium that have been linked to fracturing flow back. Of great interest is whether native contaminants are mobilized by the fracturing process and find their way towards the surface as a result of interception with naturally occurring fractures or abandoned gas wells.
While finding methane in wells adjacent to production sites implicates shale gas development; by itself it’s insufficient to constitute a causal relationship. Stray methane is fairly common in northeastern Pennsylvania. Confirming that its occurrence is a result of hydraulic fracturing would require other tests, such as analysis of isotopic signatures to reveal whether the methane is thermogenic and originated from heat in deep subsurface environments, or whether it is biogenic and owes its presence to microbial respiration.
With nearly a mile of solid rock separating the zone where fracking occurs from the phreatic zone where drinking water is most likely to be impacted, supporters of shale gas development believe the process to be inherently safe and that the potential rewards for science and communities that host development are large.
Better knowledge of baseline methane and metals levels and their seasonal variability in response to rainfall recharge, or the upward flow and mixing of waters that brings elements into and out of solution, will certainly benefit industry in cases where water quality in drinking wells appears to deteriorate coincident with hydraulic fracturing nearby.
“Fracking has been a mixed bag for the area,” says Saiers, who coincidentally hails from a small town in McKean County not far from Pennsylvania’s fracking epicenter. On annual trips home he notes how tanker trucks block the roads, but how development has rejuvenated once withering towns. “In their heart of hearts, industry believes that fracking is safe,” he says. And while he allows that the companies may be right 99% of the time, faulty well construction and accidents that lead to spills are inherent weak links in the process. His study should provide some of the most substantive data yet to settle fundamental issuesof risk arising wherever gas shale and tight oil resources are found.
YCEI is supporting the Yale Center for Law and Environmental Policy and Pace University’s Land Use Law Center in a pilot program that is developing local ordinances and training programs to help communities prudently develop shale gas resources. The program addresses long-standing issues not covered by state and federal laws. Details about the program are available here.