Hydraulic Fracturing,Horizontal Wells
&Unconventional Oil/Gas Resources
Robert A. BauerE. Donald McKay
Rend Lake CollegeJuly 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 FracturingIn 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 & cementdown to brine waters
Intermediate casing & cement
Production casing & cement
Surface casing & cement
Example of steel casings & production casing
Truthland
Production casing
Surface casing
Intermediate casing
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 Fracturingin 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
Natural joints & fractures
Horizontal Wellsfor
Shale Oil/Gas
shale
shale
Organic rich layer
Joints in shale layer
Joint Face
Joint Face
Joint Face
Joint Face
Joint Face
Perforate casing &start hydraulic
fracturing
All wells are not hydraulically fracturedThere are horizontal wells producing “naturally” in IL
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
123
According to records up to 640,000 gallons used in one horizontal well
Over 300 horizontal wells in Illinois
Micro-seismic monitoring shows extent of fracturing process
Cross-Section View of 5,000 ft horizontal well
Map View of events for a single stage.
(From esgsolutions.com)
North2,000 Feet
Concerns:
Fracturing Fluid
Water Use
Where are Unconventional Resources
Seismicity
Groundwater Contamination
Example Hydraulic Fracturing Fluids[Fayetteville Shale (Arkansas) horizontal well]
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
Typical Additives Used in Fracturing Fluid
(from fracfocus.org)
U.S. experience ~2 to 5 million
gallons per well
Water Use
2 million gallons is water used in Champaign County in about 1.5 hours
Avg water use in IL per DAY in Millions of gallons
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
USGS 2005Illinois - per DAY in Million gallons
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.
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
Management of the flowback waters
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
Shaded area - general shale oil boundary
Orange – shale mature & intense oil generation
Highest maturity area
Speculative or Uncertain Model at this time
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
-4 -3 -2 -1 0 1 2 3 4 5 6
Earthquake Magnitude
~ start ofbeing felt
~ start ofdamage
Natural earthquake
damage
-4 -3 -2 -1 0 1 2 3 4 5
~Smallestearthquakes detected in Illinois by
seismograph stations
6
Largest recorded
earthquakes in Illinois
Earthquake Magnitude
-4 -3 -2 -1 0 1 2 3 4 5
~ start ofbeing felt
~ start ofdamage
HydraulicFracturing
6
Earthquake Magnitude
1 million times less energy released
31 billion times less energy released
-4 -3 -2 -1 0 1 2 3 4 5
Earthquake Magnitude
HydraulicFracturing
One M80
One Cherry Bomb
~ start ofbeing felt
~ start ofdamage
-4 -3 -2 -1 0 1 2 3 4 5
HydraulicFracturing
6
Earthquake Magnitude
Small Apple falling 3 feet & hitting floor
~ start ofbeing felt
~ start ofdamage
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.
-4 -3 -2 -1 0 1 2 3 4 5
HydraulicFracturing
6
Felt Reports from hydraulic fracturing in Vertical Wells
Oklahoma
201119791984-199429 eventsBritish Columbia,Canada
~ start ofbeing felt
~ start ofdamage
Concerns:
Fracturing Fluid
Water Use
Where are Unconventional Resources
Seismicity
Groundwater Contamination
Dimock, Penn.
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)
USEPA Study
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)
Vidic et al., 2013
Methane Concentrations in Groundwater & Springs
239 sites NY (1999-2011)
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 flameChestnut 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