A United States Department of Energy advisory panel recently issued a report on issues relating to shale gas production, including the use of hydraulic fracturing. That report of the Shale Gas Subcommittee of the Secretary of Energy Advisory Board identified several benefits of shale gas production and hydraulic fracturing, but also discussed several concerns relating to shale gas production, and made recommendations to address those concerns. This blog's August 15 post discussed the benefits identified in the report. As to concerns, the report stated:
The Subcommittee identifies four major areas of concern: (1) Possible pollution of drinking water from methane and chemicals used in fracturing fluids; (2) Air pollution; (3) Community disruption during shale gas production; and (4) Cumulative adverse impacts that intensive shale production can have on communities and ecosystems."
(1) Possible Pollution of Drinking Water
The Subcommittee concluded that one of the most common worries about hydraulic fracturing relates to a type of event that is unlikely to occur. The Subcommittee explained: "One of the commonly perceived risks from hydraulic fracturing is the possibility of leakage of fracturing fluid through fractures into drinking water. Regulators and geophysical experts agree that the likelihood of properly injected fracturing fluid reaching drinking water through fractures is remote when there it is a large depth separation between drinking water sources and the producing zone. In the great majority of regions where shale gas is being produced, such separation exists and there are a few, if any, documented examples of such migration."
The Subcommittee shares the prevailing view that the risk of fracturing fluid leakage into the drinking water sources through fractures made in deep shale reservoirs is remote."
The report stated that if a water well becomes contaminated, it is less likely to be contaminated with fracturing fluid than with methane, the principal component of shale gas ("shale gas" is sometimes used in referring to natural gas produced from shale). The report concluded that, "Methane leakage from producing wells into surrounding drinking water wells, exploratory wells, production wells, abandoned wells, underground mines, and natural migration is a greater source of concern."
The report stated, though, that if a water well is contaminated with methane, the contamination is not necessarily the result of fracturing. "The presence of methane in wells surrounding a shale gas production site is not ipso facto evidence of methane leakage from the fractured producing well since methane may be present in surrounding shallow methane deposits or the result of past conventional drilling activity."
And, if a hydraulically fractured well is the cause of contamination, the pathway for flow of contaminants is less likely to be fractures created in shale during the fracturing process than it is to be a pathway that results from a well construction failure -- specifically, a poor casing or cementing job. In fact, noted the report, a poorly cased and cemented well could potentially leak "regardless of whether the well has been hydraulically fractured."
The report stated that surface spills also potentially could cause contamination of shallow drinking water formations. But the potential for contamination from surface spills is a hazard that is not unique to the fracturing process, or to the oil and gas industry. Our society uses a number of hazardous chemicals in a variety of industries.
(2) Air Pollution
The Subcommittee noted two air pollution concerns. One relates to emissions from the use of diesel engines for various purposes, including running pumps, at the fracturing site. The report suggested that gasoline engines or electric motors could be substituted for diesel engines. A second air pollution concern is leakage or emissions of methane during drilling and during the subsequent production, processing, and transport of natural gas. The report explained that methane emissions are a concern because methane is a more potent greenhouse gas than carbon dioxide. Regulators and industry already are addressing this concern, as will be discussed in more detail in a future post by this blog discussing the report's recommendations.
(3) Community disruptions and (4) Cumulative Impacts
The report expressed concern about traffic congestion and other issues that can arise from actions that are not disruptive or problematic individually, but which cumulatively can have a disruptive effect when such actions are repeated many times.
Other Concerns Identified in Report
In addition to the four main concerns discussed by the report, the report noted that water supply issues sometimes can be a problem. The report notes that hydraulic fracturing of a typical shale gas well requires between 1 and 5 million gallons of water. The report states that, "While water availability varies across the country, in most regions water used in hydraulic fracturing represents a small fraction of total water consumption. Nonetheless, in some regions and localities there are significant concerns about consumptive water use for shale gas development."
The report noted that proper disposal of flowback water also sometimes is an issue. The report noted that one way to deal with flowback is to recycle it for use as part of the fracturing fluid in future frack jobs. This reduces the amount of flowback that requires disposal, and reduces the amount of new water which must be supplied. Companies are using such recycling on a more frequent basis.
Report's Observation about the Public Debate
The Subcommittee's report also made observations about the seemingly conflicting claims of proponents and opponents of hydraulic fracturing. The report notes that supporters of hydraulic fracturing state that it has been performed safely without significant incident for over 60 years, and the report acknowledges that the supporters of fracking have a point.
Opponents point to failures and accidents and other environmental impacts, but these incidents are typically unrelated to hydraulic fracturing per se and sometimes lack supporting data about the relationship of shale gas development to incidence and consequences."
But the report suggested that supporters' references to the lack of documented problems caused by fracking will not win the public relations battle, and that some opponents do point to real problems, even if the problems generally do not arise from the fracking process itself. The report observed that proponents and opponents look at a different scope of activities in judging hydraulic fracturing.
The report states: "Some of this difference in perception can be attributed to communication issues. Many in the concerned public use the word 'fracking' to describe all activities associated with shale gas development, rather than just the hydraulic fracturing process itself. Public concerns extend to accidents and failures associated with poor well construction and operation, surface spills, leaks at pits and empowerments, truck traffic, and the cumulative impacts of air pollution, land disturbance and community disruption."
The Subcommittee stated that some of its observations perhaps could be extended to other types of oil and gas operations, but that the Subcommittee intended to focus on shale gas development and that the Subcommittee "caution[s] against applying our findings to other areas, because the Subcommittee has not considered the different development practices and other types of geology, technology, regulation and industry practice."
In a subsequent post, this blog will discuss the report's recommendations, some of which are steps that regulators already are being taken by regulators.