Energy Exploration: Hydraulic Fracturing and Water Demand'

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Energy Exploration Hydraulic Fracturing and
Water Demand.
Seun Olatubi
30th April 2007
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The Search.

• The search for energy sources is increasingly
  rapidly as population growth continues to
  increase and the standard of living is generally
  increasing the phenomenon translates to higher
  energy demands.
• This has prompted a widespread search for
  energy by energy companies in areas deemed
  uneconomic to explore before as energy prices are
  high enough to justify the exploration costs.
• Certain geologic formations such as tight sands,
  oil shales and coal bed methane formations are
  formations that generally suffer from poor flow
  rate due to poor permeability or clogging of the
  formations during drilling
• To overcome the challenges of these formations
  Hydraulic fracturing is one technology used in
  the exploration activity

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Introduction to hydraulic fracturing
Soure US department of Energy Office of
Environmental Management
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Hydraulic fracturing contd..

• Hydraulic fracturing involves the following easy
  steps (condensed)
• The well is drilled into the depth required
• Water, that contains certain additives (to
  increase viscosity) is pumped into the well to
  create high pressure (usually in the 3500 psi
  range)
• The drilled formation cannot withstand the
  pressure so it cracks
• These cracks ensure better flow of the oil or gas
  to the well
• A propping agent, usually sand carried by the
  high viscosity additives, is pumped into the
  fractures to keep them from closing when the
  pumping pressure is released. The high viscosity
  fluid becomes a lower viscosity fluid after a
  short period of time. Both the injected water and
  the now low viscosity fluids travel back through
  the man-made fracture to the well and up to the
  surface.
• The water (produced water) and the additives
  added are usual disposed of by re-injection into
  a dedicated well.

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Source Gregg drilling
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Problems with the Water Use (the Issue)

• It is estimated that about 5 million gallons per
  well is used in the fracturing operations and
  there are multiple wells being drilled by the
  different operators
• It is estimated that 390 million gallons of
  water per day go into re-injection disposal and
  less than 1 of this is re-used.
• Exploration companies usually get the fresh
  water from local municipal authorities and the
  water is increasingly not there to feed the
  energy demand
• Sometimes the water is trucked from hundred of
  miles to the drilling location, also the produced
  water is also trucked to sites for re-injection.
  These vehicular traffic flow (sometimes for 24
  hours) usually is a nuisance to host communities.
  

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A single well might require 700 of these trucks
to transport its flow back to the disposal
facility (courtesy Conoco Philips)
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Possible Water Saving Measures

• Membrane technology is being investigated in
  dealing with the issue of re-using the produced
  water for beneficial use
• The major treatment method needed to make the
  produced water useable would be desalination. The
  majority of produced water contains salts and
  some toxic constituents which can be removed or
  reduced to non-harmful concentrations and the
  treated water can be used for other fracturing
  uses or other non-exploration activity.

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Brine Desalination Process
Courtesy GPRI, College Station, Tx.
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Results of sample(Fracture backflow) run in
Desalination Unit. Courtesy GPRI, College
Station, TX.
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Actual Savings

• Onsite desalination of frac flow could help
  reduce water that would be injected into disposal
  wells
• It would reduce the burden on host communities
  to provide fresh water
• It would be a source of fresh water for
  exploration activity
• It could be source of revenue and reduced costs
  to exploration companies
• it would help to save a portion of the 390
  million barrels re-injected daily to disposal
  wells
• It would reduce vehicular traffic in host
  communities as less hauling trucks would be
  needed

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Unresolved Issues

• Cost benefit ratio
• Market for cleaned water and perception issues

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Conclusion
Energy exploration in formations believed to be
uneconomical shall continue to rise as long as
the cost of energy justifies the exploration cost
which is directly connected to demand. This would
require need for freshwater sources which
ordinarily are not enough to meet the growing
population increase in regions where exploration
activities are being carried out, technology such
as desalination is increasingly becoming integral
to answering the water balance of commerce and
the environment.
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Questions?