FRACKING, FLOCCING, AND FRACK-SAND MININGKelvin 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

TopicsWhat is “fracking”?Where is fracking done?What are fracking sands?How did the Driftless area’s fracking sands form?Environmental consequences of frack-sand miningFracking 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

Source rock: fine-grained clay shale holding tiny dispersed oil droplets and/or bubbles of natural gas clinging to clay grains

Reservoir rock, porous sandstone

Impermeable cap rock

Natural gas

Most traditional oil/gas traps are now empty; fracking extracts oil and gas DIRECTLY from the source shales

Oil

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

Sand grains prop fractures open

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

1-2

mile

s

10,000 feet

1950

1960

1970

1980

1990

2000

2010

Oil and Gas Drilling in the U.S. Since 1950

4,000

3,000

2,000

1,000

0

Activ

e Dr

illing

Ri

gs

201

1

12

10

8

6

4

2

0

U.S. Oil Production, Millions of Barrels per Day

Frackingboom

Despite greatly increased drilling, oil production continues to decline . . .

Sources: Baker Hughes, Inc., Energy Information Administration, and Green Econometrics Researchhttp://greenecon.net/wp-content/uploads/w2008/2009/us_oil.jpg

. . . 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

www3.interscience.wiley.com:8100/.../le08_26.jpg

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.

Equa

tor

New Albin

LAND

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.

Mesh# 8/12 10/20 20/40 70/140Size, mm 2.38-1.68 2.00-0.84 0.84-0.42 0.21-0.105Size, inch 0.094-0.066 0.079-0.033 0.033-0.0165 0.009-0.004

Frack sand sizes

Ideal “proppants”: Hard, tough, chemically durable, round Quartz grainsGranite: 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.

Preferred and most widely

used

(30 to 60 grains side by side make one inch)