The recent focus on hydraulic fracturing means the industries that supply the materials (manufacturers), apply the process (service companies), and benefit from wells that produce at a higher rate (operators) have a new challenge. They have to explain the hydraulic fracturing process to policymakers and the public, describe why the process is critical to the US energy supply, and make the case for curtailing further regulation that would waste taxpayer dollars and increase the cost of energy.

This seems a strange predicament for a process that has been in use in the US for 60 years without any proven negative environmental impact. Nevertheless, hydraulic fracturing has not been in the public eye before, and there seem to be plenty of people who are willing to believe, under influence of critics whose currency is emotion rather than science, that it is a sinister new process that will pollute the environment.

Producing from shales efficiently requires multiple fractures to be placed along sections of a horizontal well bore.

The present dilemma

Confusion on the subject of fracing is unsurprising, given that there seems to be a lack of knowledge by the mainstream media. For example, reports often refer to fracturing as a “drilling process,” which it is not. However, identifying fracing as a “well stimulation” process is well beyond general non-technical understanding. Drilling and fracturing technologies may be synonymous in the public’s mind because the complexities and economics of drilling wells and extracting fuel have not been the focus of everyday literature. Simply stated, fracturing of old and new wells has the effect of increasing ultimate recovery of oil or gas, and that means it has an important — even essential — role in the nation’s energy future.

History

The first hydraulic fracturing treatment was performed in Kansas in 1947, where the frac fluid was 4,000 gallons of gelled gasoline. The first patent on the process was applied for in 1948 and was assigned to Stanolind Oil and Gas of Tulsa, Okla. Industry engineers, scientists, and universities have been doing research on hydraulic fracturing ever since. A total of 204 US patents have the words “hydraulic fracturing” in the title or abstract of the patent.

Shale fracturing

Drilling activity in new areas has introduced fracing technology in regions where it is not well understood. (Image courtesy of Frac Tech Services)

The process has changed little over the years. It still uses the hydraulic pressure of the frac fluid, pumped down the well at a high rate, to fracture the earth around a well bore. When fluid pressure at the bottom of the well builds to a value greater than the stress on the rock around the well, a crack or fracture forms in the rock. In all wells except very shallow wells, the fracture is vertical and, in conventional reservoirs, vertical growth is limited by changes in elasticity or strength of the rock in different strata.

In shales, the hydraulic fractures are quite different. Natural fractures are scattered throughout the rock, with spacing varying in different spots. Microseismic data, which record a small noise generated in the reservoir when rock cracks or slips, indicate a very complex process involving opening of natural fractures while frac fluid is being injected. Instead of a single fracture in the formation, displacements of the rock (cracks) occur within an irregular area, generally in a direction determined by the direction of horizontal stresses in the earth. The details of how the microseismic events occur are different in different wells and reservoirs. Slick water and small proppant are usually used.

Multiple fracture treatments are usually placed along sections of a horizontal well bore. Because multiple fractures are formed, large volumes of water must be pumped into a well. Unfortunately, it seems the very scope of these frac jobs is partially responsible for the amount of undue attention the process is receiving.

It is fair to say that hydraulic fracturing is in the public eye today because of technologies for horizontal drilling and fracturing shale deposits. Opponents to fracing would benefit from understanding this process and how it is carried out in the field.

Environmental issues

The frac fluid used today primarily is water. One of the main concerns of politicians, environmentalists, and community activists who want to increase regulation of hydraulic fracturing arises from concerns about chemicals added to the frac fluid.

This concern about additives was exacerbated initially by reluctance on the part of some service companies to provide detailed information on frac fluid composition. Generally, the types of chemicals used in frac fluids have been public knowledge for years. Much information is published in the trade and patent literature. It is not a secret.

There are water-soluble polymers — the most common being guar gum or its derivatives, which degrades and does not move through the earth — and very small amounts of various soluble chemicals, such as polymer breakers or stabilizers, surfactants, and inhibitors.

Although E&P companies know that chemicals pumped down a well inside steel casing that is cemented in the earth could not escape and move through an aquifer to pollute a groundwater supply hundreds or even thousands of feet above, that information has not been communicated well to the general public. Instead, the message that has been most effectively delivered is the erroneous one — that frac fluid is dangerous to people’s health.

Reports can be found on the Internet and in the press claiming that hydraulic fracturing has caused damage, along with statements that refute the accuracy of the claims. Often a newspaper reports what another news source said without any independent verification. In one case, for example, an article cited four incidents in which fracturing was said to cause harm. What went unwritten, however, was that a lengthy report from a state agency about one of the incidents — gas in a home in Bainbridge, Ohio — did not conclude that hydraulic fracturing was involved in causing the gas leak.

Fracing legalities

Hydraulic fracturing has spawned surprisingly little litigation in the US over the past 60 years. A search of federal and state reported cases above trial level revealed only 39 cases including the words “hydraulic fracturing.” Several of these involved tax or contract disputes. Some involved the EPA or state agencies as a party. A particularly important case was decided by the Texas Supreme Court in 2008, where it was held that the rule of capture precluded damages for drainage by hydraulic fracturing.

The fate of bills before Congress related to regulation of hydraulic fracturing is critically important. Congress exempted hydraulic fracturing from regulation under the Safe Drinking Water Act in 2005, but a bill was introduced last summer to federally regulate hydraulic fracturing under the act.

Regulations developed by the EPA under such a bill are unknowable at this time, but they could be expensive. Congress continues to debate the need for broader regulation and has asked the EPA to study the impacts of hydraulic fracturing on drinking water sources.

The industry needs a better, more effective way to advocate and communicate the benefits of fracturing to media, to the public, and to officials whose decisions could impact the future of the technology — and of the nation’s efforts to achieve energy independence.