This document contains slides from a presentation on fracturing. It discusses the basics of fracturing, including that it has been used since the 1940s to produce oil and gas that cannot be extracted economically without it. When evaluating a potential new oil field acquisition, an environmental specialist would want to look at the field's fracturing operations to identify any pre-existing problems and avoid purchasing a field with issues. The document outlines some key terms related to drilling and well completion, such as annulus, proppant, perforating, and discusses the differences between conventional and unconventional resource development which has led to controversies over shale development.

1. Slides excerpted from my upcoming class in Colombus, Ohio on Fracturing.
(There are some slides left out, so the slides may not "flow" from one to the
next).
1/9/2014
FRACKING
INTRODUCTION
FRACTURING
• Most fracturing operations
don’t have problems
• Some petroleum cannot be
produced economically without
fracturing
• Fracturing has been used
since the 1940’s
• But, like any other operation,
you can have problems
FRACTURING
FRACKING
• Not so hypothetical question:
– Company B wants to sell their oilfield to
Company A
– You are an environmental specialist,
working for Company A
– Your boss asks you to evaluate whether
there are problems due to fracking
– What do you evaluate, to avoid buying a
field with problems?
– If there’s “no baseline data,” how can you
do your job?
– What, mechanically, causes the problems?
FRACTURING
FRACKING
• Buy the oilfield, everything’s fine…
•
Except it isn’t fine, and you are
about to get fired
– Lisa Jackson and the guy down the
hall burst in and rescue you from
getting fired
• Analysis would be a better idea
– What do you evaluate, to avoid buying
a field with problems?
FRACTURING
FRACKING
• One way to handle it:
– Watch several documentaries
online
– Quote a federal regulator who
says fracking is fine
• Lisa Jackson even said there
were no problems. And she’s a
liberal, right?
– Quote the guy down the hall,
who says “fracking has never
caused a problem”
– Tell your boss everything is fine
– Buy the oilfield….
FRACTURING
WHAT IS FRACTURING?
• Injection of fluids under pressure to create
or enlarge fractures in reservoir rocks
• Usually, sand (proppant) is also injected
– Props the fractures open after pressure is
relieved
• Fractures become conduits for oil and gas
to flow into the wellbore
MECHANICS OF FRACTURING
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2. 1/9/2014
Slides excerpted from my upcoming class in Colombus, Ohio on Fracturing.
(There are some slides left out, so the slides may not "flow" from one to the
next).
WHAT IS PROPPANT?
• The frac will continue to make a fracture as long
as you continue pumping.
– Size of the fracture is proportional to how much fluid
you pump
FRACKING
• “Conventional” = Sandstones, Limestones,
Dolomites
• “Unconventional” = Shales
• When the pumping stops, the frac will close.
– Sand or some other type of “proppant” is added to the
frac fluid.
– Sand stays in the fracture and props it open.
– Oil and gas flow thru the permeable sand to the well.
George E. King, Apache Corp. SPE 152596
FRACTURING
FRACTURING
DRILLING/COMPLETION JARGON
• Drilling and completion has some of the worst jargon
in the oilfield
• We need to understand the lingo to do our jobs
• For this reason, there will be some slides that define a
term that will be used in subsequent discussion.
WE DRILL THE WELL, THEN WE “COMPLETE” IT
– These slides are not as “random” as they may seem.
WELLBORE CONSTRUCTION
DRILLING
ANNULUS
CIRCULATION
An annulus is a gap between two
strings of pipe, or between the
pipe and the open hole. The pipes
have to be “one inside the other”
or concentric in order to form an
annulus.
Annulus - donut shaped space
It comes from the same root word
as “annual,” as in annual growth
rings on a tree.
Usually, you cannot see the
annular space when you stand at
the well.
DRILLING
• The well must have a concentric pipe
to circulate (there has to be some sort
of annulus)
• You pump down the inside of the pipe,
and let the fluid come back up around
the outside of the pipe (the annulus, aka
the “backside”)
• Fluids that are commonly pumped
include “drilling mud” and “completion
fluid”
DRILLING
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3. 1/9/2014
Slides excerpted from my upcoming class in Colombus, Ohio on Fracturing.
(There are some slides left out, so the slides may not "flow" from one to the
next).
DRILLING
WHY DO WE CEMENT?
• The crew moves the rig to the
location
• They drill a hole in the rocks
hundreds or thousands of feet
– They “circulate” mud down the
well to bring out cuttings, while
simultaneously turning a bit to drill
into the rocks
• They will run and cement at
least one string of casing pipe
– Usually, there will be more than
one
• The crew moves the rig to the
next location
DRILLING
Cementing Casing
• We have to keep the oil from
coming up between the pipe and the
hole
– If there are drinking water aquifers,
they could be contaminated
• We want to control where produced
fluids come from and where injected
fluids go. (Zonal Isolation)
– If water disposal wells
communicate with producers, you’ll
be pumping the water in circles
DRILLING
PERFORATING
• Assume we have a cemented well, and
we are going to install a frac
completion
• After we cement the casing in the well,
the oil cannot get into the well, and frac
fluid cannot get out into the formation
• We “perforate” holes in the pipe with
explosive charges
– Bullets shoot holes thru the pipe and
cement, and into the formation
COMPLETION
PERFORATING
PERFORATING VIDEOs
• Bullets shoot holes thru the pipe
and cement, and into the formation
• They can aim the perforating gun
in a particular direction they are
perforating so the frac will open
against the minimum horizontal
stress
• First video: shaped charges
• Second video: blowing up just the
primer cord, to loosen bolts on an
old wellhead
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4. 1/9/2014
Slides excerpted from my upcoming class in Colombus, Ohio on Fracturing.
(There are some slides left out, so the slides may not "flow" from one to the
next).
FRACTURING
FRACTURING
FRACTURING
DIFFERENT FROM PRIOR “OIL
BOOMS”
Conventional oil and gas development would
be restricted to the anticlines shown in red and
dark green. By contrast, shale development
stretches across the countryside overlaying the
“SHALE ZONE” layer.
Towns have already been built – no way to keep development separate from
urban areas.
WHAT’S THE CONTROVERSY?
SHALE ZONE
FRACTURING
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