Fracking
It
may shock you to know that the anti-fracking campaign is as guilty as
the pro-fracking oil and gas industry of being inaccurate. Rather
than look at all aspects of fracking I am therefore going to
concentrate on some misconceptions. There are plenty of other aspects
I could write about, so this maybe just the first of a series.
Can
fracking lead to contamination of drinking water?
In
theory it can, but there are no proven instances. The oil and gas
industry is less regulated in America than it is here, though even
there liners are placed all the way from the surface to the shale
being fracked. After all it is in no ones interest to loose oil and
gas on the way up. I would like to think that drill-hole liners would
be heavily regulated in this country, to ensure that under normal
circumstances contamination of aquifers could not happen. Fortunately
we don’t have earthquakes big enough to damage liners in this
country. Much of the opposition to shale gas exploration has been
generated by Josh Fox’s film Gasland
which
is marketed as a “documentary”. This contains the astonishing
film of one Mike Markham, of Weld County, Colorado, setting fire to
water emerging from a his bathroom tap. This has nothing whatsoever
to do with adjacent shale gas production. The phenomenon was
investigated by the Colorado Oil & Gas Conservation Commission in
2008 who concluded that the gas was biogenic methane. This conclusion
was not as exciting as the film clip, and so has passed the media by.
In Texas in 2010 year there were reports of groundwater contamination
by shale gas. The Environmental Protection Agency slapped an
emergency protection order on Range Resources’ production of gas
from the Barnett Shale in Parker County. Subsequent investigation
revealed, however, that the contamination predated the shale-gas
fracking. The contaminating gas consists of a mix of methane and
nitrogen, and nitrogen does not occur in the Barnett Shale gas. It
is, however, characteristic of gas from sands in much shallower
sediments.
What
is used in the fracking?
Between
50,000 ad 350,000 gallons of fluid are used during a fracking
treatment, plus 75,000 to 320,000 lbs of sand to hold the fractures
open. There are also the nasty additives being used in fracking. This
website gives a list:
http://fracfocus.org/chemical-use/what-chemicals-are-used
It
sounds worse than it is because most of them are inert, and most of
the liquid is water. BUT every company uses a different mix and some
are much worse than others. Shell insist that they use very little
apart from water, sand and gypsum, though this doesn’t let them off
the hook, where is all the water going to come from? And all the
sand? More holes in the ground to put our rubbish in?!
How
leaky are the fractures?
Real
data collected on many thousands of hydraulic fractures indicate
that the fractures are almost unviersally contained within the shale
being fractured, and do not extend into adjacent aquifers if present.
This however doesn’t mean that fractures can’t and don’t extend
into aquifers. There is also the question of natural faults, ie
natural fractures along which movement has occurred in the past,
causing a displacement of the rocks either side, they can either seal
against or enhance lateral and vertical fluid movement depending upon
the type of fault. This is one I have not heard anyone mention apart
from a retired colleague, and if it had occurred to both of us it
must have occurred to others. In the geological basins being fracked
in the USA the natural fault density is low, in the UK it is high,
not least in the Kimmeridge Clay (actually a shale) being
investigated at Balcombe. What will happen if a faulted shale is
fracked? We believe that the faults, or at least some of them, will
be reactiviated, and may allow fracking fluids to extend much further
than is suggested by the theoretical and experimental work. We also
suspect that it was a fault reactivation that caused the (very minor)
earthquake in Lancashire that has been linked to testing for shale
gas.
The
cost of gas and the value of Campaigning
While
Quadrilla were being worried into reducing the scale of their
operations around Balcombe I was discussing shale gas and shale oil
with oil company geologists, and I thought you would find what they
see in their crystal balls rather interesting.
In
the 19th
century Oil Shale (when it is called oil shale rather than shale oil
it means the hydrocarbons have not matured sufficiently to become oil
or gas and therefore be able to flow) was quarried and burnt, causing
horrendous pollution: no one wanted to repeat that. Twenty years ago
getting hydrocarbons out of shale was dismissed as fantasy, utterly
uneconomic. Then the price of oil rose steeply, and at the same time,
country’s with highly developed oil technology such as the USA and
the UK found themselves running out of hydrocarbons. Suddenly, even
though vastly more expensive than conventional hydrocarbon
extraction, shale began to look attractive, BUT, only onshore.
Offshore shale gas/oil extraction is still considered too expensive.
With enough campaigning and the continuing rise in the price of oil
we will drive shale gas/oil extraction offshore. In an ideal world we
would not be burning our precious oil and gas reserves, but using
them in other ways (eg plastics), unfortunately that is simply not
going to happen, at least not for a long time, but if we can drive
the oil industry back off shore, we can at least protect our
landscape and aquifers.
Jenny Huggett (updated 17/8/2013)
