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
Intermediate casing & cement Production casing & cement Surface casing & cement
Example of steel casings & production casing Truthland Production casing Surface casing Intermediate casing 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 Fracturing in vertical wells First used in 1947First used in 1947 Millions of vertical wells have been fractured in U.S.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.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 IndianaRecently 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 Wells for Shale Oil/Gas shale shale Organic rich layer
Joints in shale layer Joint Face
Perforate casing & start hydraulic fracturing All wells are not hydraulically fractured There 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) North 2,000 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 AcidDissolves 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~11 million gallons a day 2% of Ag or 0.6% of Public supply or 0.08% of Power use in ILL2% of Ag or 0.6% of Public supply or 0.08% of Power use in ILL USGS 2005 Illinois - 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 surfaceNot felt at surface Do not cause damageDo 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 ~ start of damage Natural earthquake damage
~Smallest earthquakes detected in Illinois by seismograph stations 6 Largest recorded earthquakes in Illinois Earthquake Magnitude
~ start of being felt ~ start of damageHydraulicFracturing 6 Earthquake Magnitude 1 million times less energy released 31 billion times less energy released
Earthquake Magnitude HydraulicFracturing One M80 One Cherry Bomb ~ start of being felt ~ start of damage
HydraulicFracturing 6 Earthquake Magnitude Small Apple falling 3 feet & hitting floor ~ start of being felt ~ start of damage
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 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 Northeast British Columbia, Canada One magnitude 3.8 felt by workers 38 events recorded from (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.
Hydraulic Fracturing 6 Felt Reports from hydraulic fracturing in Vertical Wells Oklahoma events British Columbia, Canada ~ start of being felt ~ start of damage
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 ( )
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
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 – 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