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

rabauer@illinois.edu