American Oil and Gas Reporter - March 2016 - 74

SpecialReport: Unconventional Resource Science

New Tools Enable Better Completions
By Colter Cookson
With production performance varying
from one well to another on the same
pad, and even from one stage to another
along a single lateral, optimizing stimulation designs from the toe to the heel
can have measurable impacts on a well's
completion efficiency, economic performance, and ultimate recovery potential.
Service companies and manufacturers
are introducing new technologies to give
engineers the ability to optimize all aspects
of stimulation design, from determining
where to place perforations, to making
treatment adjustments on the fly for each
individual stage, to using diagnostics and
precise temperature/pressure data to further
optimize frac designs on future wells.
Of course, designing an effective completion requires placing the right proppant
in the stimulated reservoir volume.
Whether a job calls for ultralight materials
that will reach the end of even the longest
fracture or ultratough materials that can
withstand the extreme pressures of the
Lower Tertiary, proppant manufacturers
stand ready. The newest solutions even
include proppants that reveal their locations
within the fracture network once they
are pumped downhole.
To deliver the proppants, pump manufacturers report developing durable but
affordable systems that can deliver high
horsepower efficiently over extended operating periods. Meanwhile, water treat-

96/125
(6,150')

ment specialists continue to refine the
technologies and expertise that are allowing customers to recycle or discharge
produced water safely and reliably.
According to service providers and
manufacturers, the latest completion advances share a common goal: to ensure
that every completion maximizes well
economics by increasing production at
an affordable cost.
"Even the best equipment, proppant,
frac fluids and downhole tools can do
only so much with an ineffective completion design," warns Dale Logan, vice
president of reservoir technologies for
C&J Energy Services. "To maximize
completion effectiveness, growing numbers
of completion engineers are moving from
a geometric, spacing-based approach to
'engineered completions' that consider
variations in geology within the lateral."
That approach is key in plug-and-perf
completions, Logan reports. "In these
completions, operators initiate multiple
fractures simultaneously in each stage.
In a computer model that assumes uniform
geology, that works well. But in practice,
because of lateral heterogeneity, many
of the fractures will be overtreated or undertreated," he explains.
To prevent that from happening, completion engineers can place each stage's
perforations in rock with comparable unconfined compressive strength. It is possible to determine unconfined compressive
strength with wireline logging techniques,

First Year Cumm Production
Oil
1,800,000
1,500,000

79/115
(5,550')

1,200,000
900,000
600,000

40/85
(4,400')

300,000
0
1

91
Well 1

181
Well 2

271

361

Well 3

Geological variations along a lateral (left) contribute to differences in well performance
within a field (right). By using drilling data to track geological variations and identify the
best spot for each perforation, C&J Energy Services reports it is boosting completion
effectiveness and therefore well production.

74 THE AMERICAN OIL & GAS REPORTER

but Logan says doing so is expensive in
horizontal wells. He puts the cost before
rig time between $20,000 and $100,000.
Through its new LateralScience™ engineered completion service, Logan says
C&J is offering a more economic approach. "The idea is to use drilling data
that operators have collected already to
place perforations," Logan outlines. "The
drill bit reacts to the geomechanical properties of the rock similar to the way a
fracture will, so if rock is tough to drill,
it will be tough to fracture."
According to Logan, the technique involves using mechanical specific energy
as a proxy for unconfined compressive
strength. "It will not determine the actual
unconfined compressive strength, but it
can reveal the relative unconfined compressive strength and allow operators to
place perforations in 'like' rock," he says.
The technique has been applied to
175 wells to date, Logan says. While
most of those wells are in the Eagle Ford
and Permian Basin, he says the company
also has applied it in other plays, such as
the Marcellus and Bakken.
"We are doing studies comparing the
wells that used the technique with other
wells in the area that were completed in
a similar fashion," he relates. "The early
returns suggest that wells using the technique are better than the ones around
them. Most are in the top quartile.
"Using drilling data to place perforations is only the beginning. Once the industry accepts that drilling data can help
evaluate the reservoir, there are other
problems they will address with this approach," Logan predicts.
As an example, he points to workovers.
"By using drilling data to figure out
which wells were completed effectively
and which ones were completed poorly,
operators will be able to avoid wells that
have little to gain from a workover and
identify ones where a workover might be
particularly beneficial," he says.
Logan adds that drilling data may help
operators maintain development programs.
"Without those data, an operator who
drills a string of unimpressive wells may
think he has reached the edge of the field
and stop drilling. He may be right, but
what if the wells' poor performance comes
from problems with the completion design? Drilling data may let him identify
and fix those problems so he can keep

American Oil and Gas Reporter - March 2016

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