31 July 2013

The Ins and Outs of Fracking and Underground Waste Injection Wells

Posted by John Freeland

When the Akron Beacon-Journal Online publishes its updated interactive map of active, permitted, and producing oil and gas wells in Ohio, it places another map right below it. The second map shows underground waste injection wells. These two maps belong together because underground injection wells are used to dispose of the polluted flowback water from high volume hydraulic fracturing (fracking) operations.

When thinking about potential for groundwater contamination, hydrofractured oil/gas wells and underground waste injection wells differ in an important aspect. While “frack” wells use pressurized fluids and sand to force open fissures in shale rock, the fluid pressure is released during “flowback.” The ultimate goal of fracking is extraction of valuable hydrocarbons from the shale. Brine usually comes up along with the oil and gas. Extraction reduces the fluid pressure in the rock formation and well casing.

Where does injected waste go?
In the case of waste injection wells, there’s no “flowback” unless there’s a failure. The goal is to push junk down the well and never see it again. Unlike oil/gas frack wells, there’s no reversal in pressure to extract valuable materials from the rock formation receiving the waste. It’s a one-way trip down the well with the very real potential of building up pressure as more waste is injected.

The porous rock formations that are used for deep waste injection contain void spaces that are usually filled with saline water. Usually, the deeper one samples groundwater, the saltier it gets. Saltier water is more dense than less salty water.

The groundwater mostly found in deep injection formations is unfit to drink even prior to the injection of wastes. Information about depth to saline groundwater is available through the USGS and depicted on the generalized map below. According to the map, saline ground water in Ohio is found at less than 500-feet below the ground surface. Utica shale oil/gas wells and deep waste injection wells are thousands of feet deep.


The problem with the deep saline groundwater isn’t just saltiness. As noted by the USGS, “Saline ground water also may contain some constituents, such as arsenic, elevated radioactivity, and dissolved organic material…”

What worries me about underground waste injection is that the waste is not being injected into a vacuum. In order to get fluid into a rock pore, whatever fluid is already there has to move out. Where does it go?

Earthquakes and New Regulations
A series of twelve small earthquakes (2.1-4.0 on the Richter Scale) within a mile of an injection well in Youngstown, OH has been attributed to frack waste injection.

The Youngstown earthquakes and the follow-up investigation have prompted some new regulations from the Ohio Department of Natural Resources, which is allowed by the EPA to administer the regulatory program for injection wells in the state. One of the provisions is to monitor pressures within the wells and shut them down when maximum allowable pressures are exceeded.

The use of underground injection to dispose of waste has been around since the 1930s. The United States EPA regulates six different classes of injection wells under its Underground Injection Control (UIC) Program. The different classes “are based on similarity in the fluids injected, activities, construction, injection depth, design, and operating techniques.” Details are available at the EPA UIC Program website.

The wells receiving waste brines from oil and gas production wells are Class II wells. According to the EPA, there are 172,068 such wells in the United States.

Sensitive to regulatory and public concerns, as well as likely rising costs for disposal, energy companies are apparently taking steps to reduce, re-use, and recycle water used for fracking. However, both water supply and waste disposal remain big headaches for the industry.

A joint online effort, called fracfocus.org was started by the Ground Water Protection Council and the Interstate Oil and Gas Compact Commission to provide a registry of information on an individual oil/gas well basis, across the United States.

What the Akron Beacon-Journal publishes is a good start, but I’d like to see more information made available about the underground waste injection wells. Would it be feasible to publicly disclose and make available online a registry including detailed logs of what kinds, when, and how much waste was pumped down a given waste injection well? How often are the wells inspected? Maybe such records exist. I’m still looking.