Frac disclosures

Dec. 13, 2010
The controversy surrounding perceived hazards of contaminating ground and surface fresh water from hydraulic fracturing has led service companies and operators to disclose much more about the fluids and practices that are essential for tapping the vast gas and oil resources trapped in shales, tight sands, and coals.

Guntis Moritis
Production Editor

The controversy surrounding perceived hazards of contaminating ground and surface fresh water from hydraulic fracturing has led service companies and operators to disclose much more about the fluids and practices that are essential for tapping the vast gas and oil resources trapped in shales, tight sands, and coals.

In the US, state and federal agencies have changed the rules or are studying the need for making changes to the rules concerning fracturing operation and the disclosure requirements for the fluids pumped downhole during the treatments.

For service companies, the main objection to full disclosure has been to protect intellectual property rights. Their chemical formulations are typically held confidential as trade secrets and not patented.

Currently most companies say that they are willing to provide full disclosure of the constituents to state regulators as long as the regulators treat the information as confidential and use it only to provide information for oversight and emergencies.

The frac fluid constituents often are also posted at the wellsite on material safety data sheets and many companies have put information on the fluid constituents on their websites.

Fracturing

Modern ideas on fracturing date back to the late-1940s and since then one estimate is that the oil and gas industry has performed more than 2.5 million fracture treatments worldwide.

Initially the base fluid of choice was refined or crude oil but this has changed over the years as the benefits of other fluids became better understood. Currently the main fluid found in frac treatments is water containing proppant, such as sand, with a small percentage of additives that aid in carrying the sand downhole, as well as in reducing the pump pressure needed and in preventing bacteria growth.

Because of natural and man-made barriers, the industry has contended that there is a minimal chance for groundwater contamination and that well documented cases of contamination do not exist. The main natural barrier is the thousands of feet of formation that typically separate the treated interval from the groundwater and the man-made barriers are the well completion practices for isolating the groundwater zones from the rest of the wellbore.

To further allay fears of groundwater contamination, companies are introducing frac fluids with less hazardous additives. Halliburton recently introduced a fluid based on the same constituents and concentrations found in food industry products that range from baby wipes to beer. Although these ingredients are commonly found in households, Halliburton cautions that some are still labeled as hazardous based on their physical and health effects. To date, Halliburton has treated three wells in different basins with this fluid.

Halliburton's web site also has information on the typical constituents in frac treatments pumped into formations such as the Marcellus in Eastern US.

Baker Hughes is another company that has launched a family of environmentally preferred fracturing fluids and additives. Baker Hughes says its fluids and additives are vetted for safety, performance, compatibility, and value and are for fracturing systems such as slickwater, linear gel, crosslinked, and viscoelstic.

Additional information of frac fluids pumped can also be found on operator websites such as those of Range Resources and Chesapeake Energy.

Risks

To understand the nature of the risks associated with the these fluids, Baker Hughes has developed a scoring system for these ingredients base on risks associated with the environment, human health, and physical hazards.

Risk is based on both the nature of the hazard and the exposure time.

Environment risks include aquatic toxicity, bioaccumulation, biodegradation, priority pollutants, and volatile organic compounds. Human health risks include mammalian toxicity, irritation-corrosion, carcinogenicity, genetic toxicity, and reproductive and developmental toxicity. Under the third category are physical hazards such as explosiveness, flammability, oxidization, and corrosiveness.

If widely implemented, the scoring system will allow companies to compare and select products that are environmentally preferred.

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