FRACKING, FLOCCING, AND FRACK-SAND MINING
Kelvin S. Rodolfo, Professor Emeritus
Department of Earth & Environmental Science
University of Illinois at Chicago
Frack Sand Mining Forum, New Albin, Iowa Community Center
14 October 2012
Topics
What is “fracking”?
Where is fracking done?
What are fracking sands?
How did the Driftless area’s fracking sands form?
Environmental consequences of frack-sand mining
Fracking won’t happen here, so is it OK for us to provide
sand for fracking elsewhere?
IF THERE IS ENOUGH TIME:
Environmental consequences of fracking
Groundwater pollution
Methane leakage and global warming
Does fracking cause earthquakes?
Consequence or staying hooked on natural gas and other
fossil fuels
TRADITIONAL OIL AND GAS SITUATION
Most traditional oil/gas traps are now empty; fracking
extracts oil and gas DIRECTLY from the source shales
Impermeable
cap rock
Natural gas
Oil
Reservoir rock,
porous sandstone
Source rock: fine-grained clay shale holding tiny dispersed oil
droplets and/or bubbles of natural gas clinging to clay grains
Unlike traditional production
from oil traps in very rare
places under small areas,
fracking operations are very
widespread and involve many
more drilling rigs.
So many more people are
affected.
Hydraulic fracturing; induced hydraulic
fracturing; hydrofracturing; hydrofracking.
Wells drilled 1-2 miles deep into fine-grained shales, then
horizontally as much as 10,000 feet. Fracking fluid forced
under high pressure (5,000 PSI) to fracture the shale. Fluid
consists mostly of water and many chemicals, plus strong,
round sand grains (“proppants”) to keep fractures propped
open so gas or oil can escape and be collected.
5,000 psi
1-2 miles
Sand grains prop
fractures open
10,000 feet
Fracking can use 2 to 3 million US gallons of fluid per well.
Typical well uses 100,000 gallons of chemical additives of
varying toxicity
4,000
U.S. Oil Production, Millions of Barrels per Day
Despite greatly increased drilling, oil
production continues to decline . . .
12
10
Fracking
boom
8
2011
3,000
2,000
Sources: Baker Hughes, Inc., Energy Information Administration, and Green Econometrics Research
http://greenecon.net/wp-content/uploads/w2008/2009/us_oil.jpg
2010
2000
1990
1980
1970
2
1960
0
6
4
1,000
1950
Active Drilling Rigs
Oil and Gas Drilling in the U.S. Since 1950
0
. . . But U.S. Natural Gas Production is Booming!
http://peakwatch.typepad.com/.a/6a00d83452403c69e20133ecc4d8ef970b-800wi
Oil/Gas shale prospect areas
None in WI or IA, but
frack sand is abundant!
Proposed
New Albin IA
North America
550 - 450 million years ago
LAND
New Albin
Most of North America
covered by a warm,
shallow sea, no deeper
than 100 feet. Areas
were sometimes above and
sometimes below sea level
for tens of millions of
years.
Granites and other rocks
far “north” of our area
were sources of quartz
sands.
www3.interscience.wiley.com:8100/.../le08_26.jpg
Nature expended huge amounts of time
and energy to make well rounded, well
sorted quartz sand grains.
The most important benefit to
humankind: Such deposits make the
best groundwater aquifers.
But the same properties also make the
sands the most abundant “proppants”
for fracking.
Frack sand
Mesh#
8/12
Size, mm 2.38-1.68
Size, inch 0.094-0.066
(30 to 60 grains side by side
sizes
make one inch)
10/20
2.00-0.84
0.079-0.033
20/40
70/140
0.84-0.42
0.21-0.105
0.033-0.0165 0.009-0.004
Preferred and
most widely used
Ideal “proppants”: Hard,
tough, chemically durable,
round Quartz grains
Granite: Typical original source of quartz grains. When weathered and
worked by streams, waves and the wind for tens of millions of years, all
minerals are destroyed except quartz grains, which are rounded.