American Oil and Gas Reporter - January 2012 - 64

Oil & Gas Shales
Now the same techniques pioneered
in a growing roster of shale gas plays are
being applied in tight oil and liquids-rich
formations. "The industry unlocked shale
gas with a litany of advanced technologies,
namely extended-reach horizontal drilling
and multiple-stage fracs," explains Trammel. "The good news was that we found
a lot of gas. And the bad news was that
we found a lot of gas. Prices dropped
and the recession hit, putting gas producers
in a crunch. But the payoff was that we
also have unlocked tight oil using the
same technology. It is quite a payoff because it could mean 50 billion recoverable
barrels of crude oil by 2025."
Trammel says tight oil or gas formations are defined as "rocks that will not
produce economic rates of oil or gas, or
achieve economic ultimate recoveries
without technology such as horizontal
drilling or multistage fracs." Unlike natural
gas targets, which are defined either as
shales or tight sands, tight oil reservoirs
include a mix of both shale and sands
that share the common characteristic of
ultralow permeability.

was unfolding in North Dakota and Montana as the industry proved that the same
set of drilling and completion technologies
also could revolutionize domestic crude
oil development.
"The Bakken Shale formation was first
drilled in the 1980s with limited success,"
he says. "Beginning with a series of
vertical pilot wells in the late 1990s and
really coming on stream in 2003, Dick
Findley and others began drilling horizontally in the Middle Bakken member
in the Elm Coulee Field in Richland
County, Mt. The Middle Bakken, a naturally fractured, dolomitized zone sandwiched between the Upper and Lower
shale members, had the right productive
characteristics and the play exploded.
"The Bakken is a nice model for what
is happening today," Trammel goes on.
"The Bakken formation in North Dakota
went from producing less than 9,000 barrels a day in October 2006 to 422,000
bbl/d by October 2011, and is expected
to top 500,000 bbl/d in early 2012."
Just as telling, data from the Oil &
Gas Division of the North Dakota Department of Mineral Resources show that
daily per-well production increased by
nearly 350 percent during that five-year
period (even as the total number of Bakken
producing wells jumped from 273 to
2,970), illustrating the impact of the continual refinement of horizontal drilling
and multistage completion techniques on
well productivity (Table 1).
The Eagle Ford Shale in South Texas
is another textbook model for liquidsrich resource plays development, according

Monumental Story
After the geologic riddle of the Barnett
Shale was cracked in North Texas with
horizontal drilling and hydraulic fracturing,
other shale gas plays quickly followed,
including the Fayetteville in Arkansas,
the Haynesville in Louisiana, and the
Marcellus in Pennsylvania and West Virginia. But while these giant new shale
gas plays were stealing the headlines,
Trammel says a truly monumental story
TABLE 1

North Dakota Bakken/Three Forks Oil Production
Month/Year
Oct 2001
Oct 2002
Oct 2003
Oct 2004
Oct 2005
Oct 2006
Oct 2007
Oct 2008
Oct 2009
Oct 2010
Oct 2011

Daily oil (bbl)

Number of
producing wells

Daily oil production
per well (bbl)

202
200
192
189
220
273
419
788
1,276
1,947
2,970

9
9
8
9
17
33
99
140
126
138
142

1,801
1,724
1,580
1,672
3,731
8,883
22,738
109,929
161,239
269,594
421,816

Source: North Dakota Industrial Commission, Department of Mineral Resources, Oil & Gas Division.

64 THE AMERICAN OIL & GAS REPORTER

to Trammel. The Eagle Ford began as a
shale gas play, with the first Eagle Ford
wells drilled in 2008 producing dry gas,
similar to the Haynesville and initial Marcellus wells.
"As natural gas prices declined after the
economic downturn in late 2008 and early
2009, Eagle Ford operators moved updip
into the wet gas window to capture the
value of NGLs. Now they have moved into
the oil window," he continues. "We know
the Marcellus also has a wet gas window
and an oil window, very similar to the
Eagle Ford. The Woodford/Cana in Oklahoma is another example of a play that has
dry gas, wet gas and oil windows."
According to the Texas Railroad Commission, Eagle Ford oil production skyrocketed from 1,091 barrels in 2007 to
130,802 barrels in 2008, 308,139 barrels
in 2009, 4.37 million barrels in 2010 and
13.84 million barrels through only the
first 10 months of 2011 (Figure 1).
Meanwhile, Eagle Ford condensate
production jumped from 83,744 barrels
in 2008 to 7.14 million in 2010 and 16.87
million barrels between January and October 2011 (Figure 2), and production
from Eagle Ford gas wells increased from
1 billion cubic feet in 2008 to 110 Bcf in
2010 and 212 Bcf through the first 210
months of 2011 (Figure 3).
Astonishing Potential
"The rate of growth behind these Eagle
Ford numbers almost defies belief," Braziel
comments. "It demonstrates not only the
astonishing potential of tight resource
plays, but also indicates how quickly operators have ramped drilling and development activity in the Eagle Ford. The
big challenge in the Eagle Ford and other
plays is putting all the required midstream
and transportation infrastructure in place
to keep up with the pace of growth."
The success of first the Bakken and
then the Eagle Ford has opened the door
for dozens of other plays that seemingly
are popping up everywhere, Braziel says,
from the Utica Shale in Pennsylvania
and Ohio, to the Tuscaloosa in Louisiana
and Mississippi, the Heath in Montana,
the Gothic in Colorado and Utah, and
the Monterey in California, to mention a
few. Just as with shale gas, he indicates
these tight oil resource plays potentially
can change the nation's energy future
and create dramatic positive benefits to
American Oil and Gas Reporter - January 2012

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