Yesterday I learnt from an
environmentally minded geologist something rather shocking, but not
entirely surprising: a New Zealand journalist decided to carry out an
investigation into the integrity of the making of the Gaslands film
(about fracking). The idea was that he would interview everyone who
participated in the film. Every single one of them refused to be
interviewed, and it turns out they had all received payment in return
for refusing to comment on the film or the accuracy of what was
portrayed. I find this quite shocking; Gaslands should have been a
truthful film, there was lots that could have been portrayed that
would have been honest and convincing of the necessity to fight those
who want to extract oil and gas from our shale. I am deeply saddened
to learn that the film was even more of a sham than I thought it
was.
Today I attended a session on shale gas and fracking and
gleaned a couple of snippets.
I can verify the figure I
quoted of around 350,000 gallons of water per frack, BUT I gather
that the average well is fracked 10 times. Hence the confusion in the
values quoted by various sources. What is deeply shocking is that
only 10-50% of the water is recovered, and this is a figure that the
oil industry is working hard to increase.
Most of the
environmental concerns are about leakage into aquifers and leakage
from surface holding tanks for the 10-50% water that is returned.
These are factors that can be controlled, and hence the likelihood of
pollution of drinking water, soil etc is, in a well run operation,
very low. The most worrying source of water contamination should be
the escape of tracking fluids from the fractured shale. Whilst
modelling suggests that it does penetrate into the shale very
successfully, after all this is what it is intended to do, the
chemical additives are largely absorbed by the clays in the shale. In
shale being fracked for hydrocarbons the clay content is typically
40%, and because of the small size of clay particles (<4 micrometers)
the surface area for absorption is vast. For the same reason clays
are used for cleaning up contaminated land. So, it may be that
although the water moves into the shale to a distance of several
meters, the chemical additives don't get that far. The average shale
being tracked, is 10s to 100s of meters thick.
Jenny Huggett (12/10/2013)
