111
but the Marcellus Shale production is only a hundred miles (160 km) from New York
City. Radon in Marcellus Shale gas samples collected at wellheads ranged from 1
pC/l to 79 pC/l (Rowan and Kraemer 2012). With transit times from wellhead to
burner of only a few days, it may be entering people’s homes in amounts above the
EPA limit of 4 pC/l in air. Most large natural gas appliances like furnaces are vented
outside, but some smaller uses such as gas stove burners or gas ovens vent directly
into room air. Rn is the second leading cause of lung cancer in the United States,
after tobacco. If the gas was stored for a few weeks before being used, the risk
would be remediated.
Radon in natural gas, radium in produced water, and uranium in solid shale cuttings are designated by regulators as Naturally-Occurring Radioactive Material, or
NORM. These are generally considered to be an acceptable risk in the production of
oil and gas. However, some regulators are classifying radium as TechnologicallyEnhanced NORM, or TE-NORM, arguing that without the application of fracking
technology, the radium-bearing water wouldn’t be reaching the surface. Discussions
about classifying, mitigating, and remediating NORM and TE-NORM are ongoing
in the regulatory, oil & gas, mining, and radiological health communities (ICF
Consulting 2000).
6.3 Water Supply and Disposal
The amount of water needed for hydraulic fracturing is often cited as being “millions of gallons” per frack. While individual frack stages rarely use this much, the
multi-stage fracks on shale wells can easily consume tens of millions of gallons in
total. Some concerns have been raised about the impacts of this usage on local water
resources, because on some shale plays like the Marcellus, only a small percentage
of the injected frack water returns to the surface as flowback (Soeder 2017). Water
that remains in the formation downhole is removed from the water cycle, and essentially lost forever. Other shale plays in places like Texas return much more. The
USGS is attempting to assess the amount of water consumed by unconventional
O&G development on a national level using water budget models, but the issue is
complicated, data are difficult to obtain, and there are many loose ends (Carter
et al. 2016).
In the early days of shale development, operators purchased finished tap water
from local utilities for hydraulic fracturing (Soeder 2017). Experience with swelling
shales on the Gulf Coast had cautioned them to believe that only very clean water
could be used for fracking shale. This certainly had a direct impact on drinking
water supplies because the O&G industry was using actual drinking water, but the
effect has not been quantified. It turned out that most of the shales containing tight
oil and gas resources are so thermally mature that no swelling or mixed layer clays
were left to cause problems with formation damage or borehole collapse. Service
companies found that much lower quality (and far cheaper) water supplies could be
used successfully for hydraulic fracturing. Most frack water these days is obtained
6.3 Water Supply and Disposal
but the Marcellus Shale production is only a hundred miles (160 km) from New York
City. Radon in Marcellus Shale gas samples collected at wellheads ranged from 1
pC/l to 79 pC/l (Rowan and Kraemer 2012). With transit times from wellhead to
burner of only a few days, it may be entering people’s homes in amounts above the
EPA limit of 4 pC/l in air. Most large natural gas appliances like furnaces are vented
outside, but some smaller uses such as gas stove burners or gas ovens vent directly
into room air. Rn is the second leading cause of lung cancer in the United States,
after tobacco. If the gas was stored for a few weeks before being used, the risk
would be remediated.
Radon in natural gas, radium in produced water, and uranium in solid shale cuttings are designated by regulators as Naturally-Occurring Radioactive Material, or
NORM. These are generally considered to be an acceptable risk in the production of
oil and gas. However, some regulators are classifying radium as TechnologicallyEnhanced NORM, or TE-NORM, arguing that without the application of fracking
technology, the radium-bearing water wouldn’t be reaching the surface. Discussions
about classifying, mitigating, and remediating NORM and TE-NORM are ongoing
in the regulatory, oil & gas, mining, and radiological health communities (ICF
Consulting 2000).
6.3 Water Supply and Disposal
The amount of water needed for hydraulic fracturing is often cited as being “millions of gallons” per frack. While individual frack stages rarely use this much, the
multi-stage fracks on shale wells can easily consume tens of millions of gallons in
total. Some concerns have been raised about the impacts of this usage on local water
resources, because on some shale plays like the Marcellus, only a small percentage
of the injected frack water returns to the surface as flowback (Soeder 2017). Water
that remains in the formation downhole is removed from the water cycle, and essentially lost forever. Other shale plays in places like Texas return much more. The
USGS is attempting to assess the amount of water consumed by unconventional
O&G development on a national level using water budget models, but the issue is
complicated, data are difficult to obtain, and there are many loose ends (Carter
et al. 2016).
In the early days of shale development, operators purchased finished tap water
from local utilities for hydraulic fracturing (Soeder 2017). Experience with swelling
shales on the Gulf Coast had cautioned them to believe that only very clean water
could be used for fracking shale. This certainly had a direct impact on drinking
water supplies because the O&G industry was using actual drinking water, but the
effect has not been quantified. It turned out that most of the shales containing tight
oil and gas resources are so thermally mature that no swelling or mixed layer clays
were left to cause problems with formation damage or borehole collapse. Service
companies found that much lower quality (and far cheaper) water supplies could be
used successfully for hydraulic fracturing. Most frack water these days is obtained
6.3 Water Supply and Disposal