Hydraulic Fracturing,
Horizontal Wells
&
Unconventional Oil/Gas Resources
Robert A. Bauer
E. Donald McKay
Rend Lake College
July 30, 2013
Hydraulic Fracturing is also used for:
Coal Bed Methane recovery
Disposal wells in bedrock
Underground Gas Storage
Water wells
In stiff soil for remediation of contamination
Hard rock underground mining
Geothermal wells for energy production
Hydraulic Fracturing
In Oil/Gas wells
First experiment – 1947
Commercial operations – 1949
Massive hydraulic fracturing – 1970/1980s
Estimated > 1 million hydraulically fractured sections of
horizontal wells in U.S. & > 2 million in world.
Horizontal Wells in U.S.
First horizontal well – 1930’s
Common by late 1970’s
~40 thousand in U.S. over past 60 years
Concerns:
Fracturing Fluid
Water Use
Where are Unconventional Resources – Shale oil/gas
Seismicity
Groundwater Contamination
Vertical
Oil/Gas well
Horizontal
Oil/Gas well
Water Well
Surface casing & cement
down to brine waters
Surface casing
& cement
Intermediate casing
& cement
Production
casing & cement
Production casing
Intermediate
casing
Surface casing
Example of steel casings & production casing
Truthland
Example of each casing cemented
Truthland
Perforation of casing for production
Shaped charges shoot
holes through casing to
open it for conventional
Oil/Gas production.
...
..
limestone or sandstone
If Hydraulically Fractured
Pressurized water, sand,
and chemicals
open & extend fractures
...
..
Hydraulic Fracturing
in vertical wells
• First used in 1947
• Millions of vertical wells
have been fractured in U.S.
• Routine use of low volume
fracturing fluids – 8,000 to
12,000 gallons of water in IL.
...
..
• Recently 1 million gallons
used in vertical well in
Illinois Basin – in Indiana
Over 180,000 oil wells drilled in Illinois. Records past
30 years show over 20,000 have been hydraulically
fractured, virtually all in vertical wells in conventional
reservoirs.
Oil & Gas
Fields in
Illinois Basin
in Green
Horizontal Wells
for
Shale Oil/Gas
shale
Natural joints & fractures
Organic rich layer
shale
Joints in shale layer
All wells are not hydraulically fractured
There are horizontal wells producing “naturally” in IL
Perforate casing &
start hydraulic
fracturing
Pressurized water & sand
forced into fractures opens and extends them
Sand in fractures keeps
them open
– “props” them open
Hydraulic fracturing performed in separate stages
3
2
1
Over 300 horizontal wells in Illinois
According to records up to 640,000 gallons used in one horizontal well
Micro-seismic monitoring shows extent of fracturing process
North
2,000 Feet
Map View of events for a single stage.
Cross-Section View of 5,000 ft horizontal well
(From esgsolutions.com)
Concerns:
Fracturing Fluid
Water Use
Where are Unconventional Resources
Seismicity
Groundwater Contamination
Example Hydraulic Fracturing Fluids
[Fayetteville Shale (Arkansas) horizontal well]
Typical Additives Used in Fracturing Fluid
Additive Type
Purpose
Consequence of
Not Using
Friction reducer
Reduces friction
between fluid and pipe
Significantly increases
surface pressure and frac
pump engine emissions
Biocide
Eliminates bacteria in
the water that produce
corrosive byproducts
Increased risk of H2S
generation by sulfate
reducing bacteria and
increasing corrosion
Scale Inhibitor
Prevents mineral
deposits in the pipes
Blocking of fractures and
plugging the plumbing
Oxygen scavenger
Removes oxygen from
the water to protect the
pipe from corrosion
Pipe corrosion sharply
increased
Diluted Acid
Dissolves cement and
minerals in perforations
and helps initiate
fractures
Higher treating pressures
and more pump
emissions
(from fracfocus.org)
Water Use
Avg water use in IL per DAY in Millions of gallons
U.S. experience
~2 to 5 million
gallons per well
2 million gallons is
water used in
Champaign County
in about 1.5 hours
USGS 2005
North Dakota – Bakken Formation estimated 2,000 wells per year
• ~11 million gallons a day
• 2% of Ag or 0.6% of Public supply or 0.08% of Power use in ILL
Illinois - per DAY in Million gallons
USGS 2005
Flowback Waters
About 5% to 50% of fracturing fluid flows back out of the well.
Many chemicals are consumed or adsorbed by the rock and not
returned.
Usually contains dissolved minerals and formation waters which
are salty - i.e. brine with trace amounts of toxic metals and
radioactive isotopes.
Management of the flowback waters
Treated and disposed in deep disposal wells
Treated & Used in hydraulic fracturing in other wells
In Penn. some using pipes to carry to next well
& reuse in Penn. was up to 90% in 2012
North Dakota – Gov. urged companies to install piping systems
Illinois regulations require storage in tanks at drill site and
testing of water.
Concerns:
Fracturing Fluid
Water Use
Where are Unconventional Resources
Seismicity
Groundwater Contamination
Energy Information Agency
Speculative or Uncertain Model at this time
Shaded area general shale oil
boundary
Orange – shale
mature & intense oil
generation
Highest maturity area
Concerns:
Fracturing Fluid
Water Use
Where are Unconventional Resources
Seismicity
Groundwater Contamination
Seismic Risk from Hydraulic Fracturing
Hydraulic fracturing produces micro-seismic events
of magnitude -2.0 to -4.0
Only detectable by sensitive instruments in deep
boreholes.
• Not felt at surface
• Do not cause damage
Estimated > 1 million hydraulically fractured
sections in horizontal wells in U.S. and no felt
seismic events
Earthquake Magnitude
~ start of
being felt
-4
-3
-2
-1
0
1
2
3
~ start of
damage
4
5
Natural
earthquake
damage
6
Earthquake Magnitude
~Smallest
earthquakes
detected in
Illinois by
seismograph
stations
-4
-3
-2
-1
0
1
2
Largest
recorded
earthquakes
in Illinois
3
4
5
6
Earthquake Magnitude
Hydraulic
Fracturing
-4
-3
-2
~ start of
being felt
-1
0
1
2
3
1 million times
less energy released
31 billion times
less energy released
~ start of
damage
4
5
6
Earthquake Magnitude
~ start of
being felt
Hydraulic
Fracturing
-4
-3
-2
-1
0
1
2
3
~ start of
damage
4
One Cherry Bomb
One M80
5
Earthquake Magnitude
Hydraulic
Fracturing
-4
-3
-2
~ start of
being felt
-1
0
1
2
3
~ start of
damage
4
Small Apple falling 3 feet & hitting floor
5
6
Induced Seismicity Potential in Energy
Technologies - National Research Council
report 2012:
Current process of hydraulic fracturing a well
does not pose a high risk for inducing FELT
seismic events.
Only TWO felt earthquakes reported in the world
attributed to hydraulic fracturing in horizontal wells.
Blackpool, England in April 2011 - Magnitude 2.3
earthquake.
Pressure went out along a bedding plane and
intersected an apparently unstable fault which was
reactivated by the increase in fluid pressure.
Northeast British Columbia, Canada
One magnitude 3.8 felt by workers
38 events recorded from 2009-2011 (mag 2.2 to 3.8)
Occurred during hydraulic fracturing in wells in fault zone
More than 8,000 high-volume hydraulic fracturing
completions in NE BC with no felt seismicity.
Will hydraulic
fracturing trigger our
natural earthquakes?
Hydraulic fracturing
many miles above
our natural
earthquakes!
Hydraulic fracturing
only increases
pressures for several
hours to part of day.
Felt Reports from hydraulic fracturing in
Vertical Wells
Hydraulic
Fracturing
-4
-3
-2
~ start of
being felt
-1
0
1
2
1979
3
2011
Oklahoma
~ start of
damage
4
5
6
1984-1994
29 events
British Columbia,
Canada
Concerns:
Fracturing Fluid
Water Use
Where are Unconventional Resources
Seismicity
Groundwater Contamination
Dimock, Penn.
USEPA Study
Community concerned about methane in water and possible
contamination from gas wells/drilling in area.
USEPA sampled wells & at faucets at 64 homes
Each sample analyzed for 195 constituents
5 wells - Coliform (3), Barium (2) & Arsenic (2) above the USEPA and
Penn. EPA for Primary maximum contamination levels for public
water supplies.
Most considered naturally occurring substances & USEPA worked
with individual owners to set up treatment systems at the 5 homes.
USEPA (2012)
Duke University Studies – Penn. & New York
400 water samples – private wells & surface waters
Analyzed for hydrocarbons, isotopes & radionuclide levels
No deep saline brines or fracture fluids found.
Osborn (2011)
Methane Concentrations in Groundwater & Springs
239 sites NY (1999-2011)
Vidic et al., 2013
French explorers in 1626 discovered Native Americans
igniting gases that were seeping into and around Lake
Erie
In 1821, the first well (hand dug) specifically for natural
gas was dug in Western New York.
Eternal flame
Chestnut Ridge County Park,
Western NY State
Etiope, et al., 2013
Pre- and Post-Drilling Testing in Penn.
No difference found for Methane in 47 wells samples
within 2,500 feet of gas wells. 1 had increase.
Water chemistry in 233 Rural water wells tested - No
influences seen in comparison to pre-existing data.
(Boyer at al., 2011)
Pre- and Post-Drilling Testing Arkansas
127 domestic water wells in two counties
7 samples had high methane but isotope shows biogenic
in origin – not from shale gas
Major ions showed chemistry link to the two types of
bedrock – not from well drilling.
USGS SIR 2012-5273
Early USEPA study found one well in West Virginia with
gelling agent. 4 nearby old gas wells possible pathway.
Illinois regulation has drillers plug nearby old oil wells.
Illinois regulations requires Pre- and Post-drilling tests of
rivers, lakes & groundwater (wells) – First in Nation.
Sites in Colorado, North Dakota, Pennsylvania (2) & Texas
Summary
Hydraulic Fracturing
Hydraulic fracturing has been practiced since 1947
Adapting hydraulic fracturing to horizontal shale gas wells began 30
years ago but expanded use in the last decade.
10s of thousands of vertical wells have been hydraulically fractured
in Illinois for Oil & Gas production.
Estimated > 1 million hydraulically fractured sections in horizontal
wells in U.S. – no seismic events felt
– only two felt in world
Many studies performed on possible contamination – best
comparison where pre- & post- drilling tests are performed
Hydraulic fracturing is occurring many, many miles above our
natural earthquakes located in the crystalline basement
Unconventional resources of shale oil/gas in Illinois is not certain
Horizontal wells & hydraulic fracturing is & can be used for
conventional oil/gas resources and other tight formation that are
not shale or the New Albany Shale
rabauer@illinois.edu