Oil

1
Oil Flows
Hydraulic Pressure Fractures Rock
Sand lodges in fractures
FRACKINGHYDRAULIC FRACTURING
2

• The Marcellus
• Shale Formation
• Large Area
• Shallow Depth
• Lots of Gas
• Thin formation
• Tight Rock
• Jointed formation

http//geology.com/articles/marcellus-shale.shtml
3
(No Transcript)
4
Marcelus and Utica Shale are Tight Rocks

• Marcellus shale is tight, meaning not many
  small cracks between joints, so the gas trapped
  in the rock needs help to be released to the
  surface artificial fracture is the solution.
• Open joints using hydraulic fracturing or
  fracking.

5
Horizontal Drilling and Fracturing
Not to scale
Cap rock
Cap rock
6
A Typical Drilling Pad
Lets watch a movie to see what happens from
such a site
http//www.glossary.oilfield.slb.com/
7
More Than One Well per Pad
Well (6 here)
Hydraulic fracture
100s of feet
Pad
Not to Scale
many 1000s of feet
8
Direction of max horizontal stress
Geology controls the arragement
9
Ideal Arrangement of Spacing Units
10
Example Dallas/Fort Worth Airport Property,
Barnett Shale Play

• 53 pads on 18,076 acres
• Almost complete
• coverage
• Patchwork, mostly ideal
• units
• One developer

11
Some chemicals used in the procedure

• Proppant Particles, like sand, transported into
  the fractures to keep them open after fracturing
  pressure release.
• Gelling Agents Increase fluid viscosity to help
  proppant transport.
• Biocides Kill bacteria that harm the gelling
  agents.
• Breakers Decrease viscosity of the fracturing
  fluid, after the fracturing process, to improve
  flowback.
• Anti-Corrosives Protect metallic elements in the
  well.
• Friction Reducers Allow high pressures and flow
  rates.
• Acid Clean out perforations, well, fractures

http//www.epa.gov/OGWDW/uic/pdfs/cbmstudy_attach_
uic_ch04_hyd_frac_fluids.pdf
http//www.earthworksaction.org/hydfracking.cfm
12
Additives to Fracturing Fluids
From NYS DECs SGEIS, 2009
13
PROBLEM

• When the fracturing process is completed, the
  pressure is released, and much of the fracturing
  fluid backflows to the wellhead.
• The backflow is
• highly saline
• contain some heavy metals (e.g. barium,
  strontium)
• Toxic fluid additives

FLUID Recycling can ameliorate this problem but
more research is needed to achieve good results
14
Potential Problems

• Contamination of ground water and surface water
  by fracturing fluids
• Water leaks
• Gas leaks
• Interconnection of aquifers produced by fractures
  and alteration of the underground rock layers
• Destruction of the confining nature of common
  confined aquifers in SE Ohio.
• Lack of good models to predict expected impacts,
  more research is needed to understand water and
  gas circulation during and after exploitation.
• For zones that are impacted (contaminated water
  wells, etc.), for how long are they going to be
  impacted? Who is going to supply clean water to
  the affected users after exploitation ends?