Letters to the Editor (June 16)

Oil well fracturing data

Editor:

How much water does the typical hydraulically fractured well require?

There isn’t really a “typical” fractured well because the amount of water used depends on the rock formation, the operator, whether the well is vertical or horizontal, and the number of portions (or stages) of the well that are fractured. In addition, some water is recycled from fluids produced by the well, so the net consumption might be smaller at sites that recycle.

Water use per well can be anywhere from about 1.5 million gallons to about 16 million gallons.

The fracturing process uses on average about 45 million L of water for a single horizontal well, according to the Groundwater Protection Council, a group of state oil and gas regulators and environmental protection agencies.

Water pumped into fracking wells doesn’t all stay in the ground. Much of it comes back up along with extracted oil and gas. The water that comes up has a much different chemistry than the water that goes down.

Produced water typically includes salts from dissolution of the underlying rock, naturally occurring radioactive substances, and chemicals added during the drilling and fracking process.

In an analysis of more than 1,000 chemicals in fluids used in and created by hydraulic fracturing (fracking), Yale School of Public Health researchers found that many of the substances have been linked to reproductive and developmental health problems, and the majority had undetermined toxicity due to insufficient information.

Further exposure and epidemiological studies are urgently needed to evaluate potential threats to human health from chemicals found in fracking fluids and wastewater created by fracking, said the research team in their paper, and published Jan. 6, 2016, in the Journal of Exposure Science and Environmental and Epidemiology.

The research team evaluated available data on 1,021 chemicals used in fracking, a process that recovers oil and natural gas from deep within the ground by using a mixture of hydraulic-fracturing fluids that can contain hundreds of chemicals.

The process creates significant amounts of wastewater and fractures the bedrock, posing a potential threat to both surface water and underground aquifers that supply drinking water, note the researchers.

While they lacked definitive information on the toxicity of the majority of the chemicals, the team members analyzed 240 substances and concluded that 157 of them — chemicals such as arsenic, benzene, cadmium, lead, formaldehyde, chlorine, and mercury — were associated with either developmental or reproductive toxicity.

Of these, 67 chemicals were of particular concern because they had an existing federal health-based standard or guideline, said the scientists, adding that data on whether levels of chemicals exceeded the guidelines were too limited to assess.

How much sand does the typical hydraulically fractured well require? Frac sand is used to produce natural gas, natural gas liquids, and oil from shales and other tight rocks where hydraulic fracturing is required.

The prime areas for producing frac sand are in the midwestern states such as Illinois, Indiana, Iowa, Kansas, Kentucky, Minnesota, Michigan, Missouri, Nebraska and Wisconsin. The sand is usually transported by rail car due to the volume of sand required.

Frac sand usage by a run-of-the-mill horizontal well is about 13 million pounds of proppant on average, which is up to 300 truck deliveries of sand per well and up to 5,000 pounds per lateral foot of well. This is data from the United States Geological Survey Minerals Yearbooks and the United States Geological Survey Mineral Commodity Summaries, 2005-2020.

These resource requirements will place an extreme burden on the roads in Valencia County since all the water and sand will have to be trucked along with all the other required drilling equipment.

 

Tom George

Bosque Farms