About Shale Gas, its uses, recovery methods, current and future expansions.

2.  Natural gas from shale.
 Trapped in shale formations.
 Organic matter broken down by high temperature.
 Thermogenic gas.
 Reabsorbed by shale and trapped.
 Composition varies with the method of extraction and
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3. Component Typical Analysis
(mole%)
Range
(mole%)
Methane 95.2 87.0-96.0
Ethane 2.5 1.5-5.1
Propane 0.2 0.1-1.5
iso-Butane 0.03 0.01-0.3
normal Butane 0.03 0.01-0.3
iso-Pentane 0.01 Trace-0.14
normal Pentane 0.01 Trace-0.04
Hexane plus 0.01 Trace-0.06
Nitrogen 1.3 0.7-5.6
Carbon Dioxide 0.7 0.1-1.0
Oxygen 0.02 0.01-0.1
Hydrogen Trace Trace-0.02
Specific Gravity 0.58 0.57-0.62
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4.  Propagation of fractures by a
pressurized fluid.
 Injection of fracturing fluid.
 Opening up of thin cracks.
 Expansion of gas from rock.
 Old technology which is now used in
conjunction with other technologies like
horizontal drilling.
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6.  Major part of it is water, with sand and
chemical additives.
 Reduces friction, protects rock formation.
 Increases the efficiency of the process.
 Water is used only for a short-term period
of drilling.
 Local geology, hydrology and geography
affect the water requirements.
 Proppant : primarily to provide a permeable and
permanent filler to fill the void created during the
fracturing process.
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7. Additive Chemical Ingredient Purpose Common Use Of Chemical
Ingredient
Acid Hydrochloric Acid or muriatic
acid
Dissolve minerals &
initiate cracks in rock
Swimming pool chemical &
cleaner
Antibacterial Agent Glutaraldehyde Eliminates bacteria in
water
Disinfectant, Sterilizer
Corrosion Inhibitor Formamide Prevents corrosion of well
casing
Acrylic fibres, plastics
Crosslinker Borate salts Maintains fluid viscosity Laundry detergents, soaps
Friction Reducer Petroleum distillate Slicks water to minimize
friction
Used in cosmetics
Gel Guar gum or hydroxyethyl
cellulose
Thickens water to suspend
sand
Thickener
Iron Control Citric Acid Prevents precipitation of
metal oxide
Food additive
Clay Stabilizer Potassium chloride Creates brine carrier Medicines, IV fluids
pH Adjusting Agent Sodium or potassium
carbonate
Maintains effectiveness of
other components
Laundry detergent, water
softener
Proppant Silica, quartz sand Keeps fracture open Drinking water filtration
Scale Inhibitor Ethylene glycol Prevents scale deposits in
pipes
Household cleansers
Surfactant Isopropanol Reduce surface tension Glass cleanser, deodorants
Water Water To expand fracture &
deliver proppants
Landscaping, manufacturing
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8.  A type of inclined drilling.
 Kick-off Point : subsurface location just above the target oil or gas.
 Entry Point : Intersection of the drill pipe with the gas bed.
 Most reservoirs have a vast extent in horizontal direction.
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9.  Shale plays are formations containing significant amount of natural
gas.
 Geographic structures with favorable conditions for production.
 Surveyors and geologists analyze the location using surface and
subsurface techniques – LOGGING.
 Usual physical properties detected are porosity, permeability,
saturation, etc.
The shale matrix permeability is usually low. Thus requires fracturing
for production.
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10.  Extensive surveillance study carried out to determine the location of
underground reservoir.
 Ensures minimal impact of operations on local community.
 Makes comply with government regulations.
 Latest development is computer simulation.
 Use of the collected data of producing formation and create a model,
using mathematical formulas of fracture propagation, to predict possible
fracture propagations.
 Simulators allow engineers to alter the stimulation programs
(volumes and types of proppants, fluids, and additives) to evaluate how
fractures could develop within the reservoir. Shanthipriya.N

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12.  There are four stages involved in recovery process:
1. Preparing for drilling. (4 to 8 weeks)
2. Rig Work. (4 to 5 weeks)
3. Hydraulic fracturing. (2 to 5 days)
4. Production. (25 to 40 years)
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13.  Clearing of drilling area.
 Vehicle access to site and infrastructure for
water.
 Final assessment for environmental, human
health safety plans and operational procedures.
 Regulations by government.
 Assembling the rig.
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14.  Construction of the rig and drilling of well.
 Steel casing, cementing.
 Horizontal drilling.
 Production casing.
 End of drilling phase.

15.  Use of perforated guns for fracturing.
 Fracking fluid is pressurized through the well.
 The rock cracks and fluid flows farther to open up the cracks.
 Fractures are held open by the proppant.
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16.  The proceedings of the well are to be monitored for efficient process.
 Pumping rate, pressure, proppant are monitored.
 Wellbore pressure.
 Commonly pressure, pumping rate, fluid properties & proppants are
important for hydraulic fracturing.
 Gases released into atmosphere during fracturing.
 Micro seismic monitoring.
 Eddy covariance flux.
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18.  Contamination of groundwater, risks to air quality, mishandling of
wastes, migration of gases and chemicals to surface and health problems
due to these
 Air Emissions:
Particulate matter, nitrogen oxide, sulfur oxide, carbon dioxide,
carbon monoxide, methane, ethane, liquid condensates, volatile organic
compounds like BTEX.
 Groundwater Pollution:
Indirect effect-evaporation ponds-runoff due to rain-poor
pipelines carrying chemicals-breakage in waste water pipe.
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19.  Fuel powers the world. Unconventional gas recovery is easier and
economical than coal.
 Electricity Generation – reliable, cost competitive, cleaner
technology.
 Horizontal drilling in conjunction with hydraulic fracturing has made
development of shale gas resource an economically viable venture.
 Less water consumption (60 to 40%) for production of electricity
from natural gas than in coal.
 A step towards cleaner technology – less carbon emissions from
shale gas compared to coal. Shanthipriya.N

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21.  Canadian Society for Unconventional Gas.
The Institute for Energy and Environmental Research for Northeastern Pennsylvania.
National Bureau of Asian Research.
 International Energy Agency.
 Exxon Mobil.
 www.hydraulic fracturing.com
 Evaluating the Environmental Implications of Hydraulic Fracturing in Shale Gas
Reservoirs BY: J. Daniel Arthur.
 American petroleum Institute.
 The Hindu.
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