American Oil and Gas Reporter - August 2016 - 67

SpecialReport: Hydraulic Fracturing Technology
6H had a 33 percent higher decay rate
than the even stages (the odd stages in
the 8H had an 8 percent lower decay rate
than the even stages).
Production Performance
Figure 6 shows the production profiles
observed in the first eight months of operation for wells 6H and 8H. The charts
highlight exponential decline functions
fitted to relatively clean portions of the
profiles (three months onward) to understand the decline behavior in the two
wells. Reasonably good fits were observed
for both wells.
The analysis found a lower exponential
decline rate for Well 6H (-0.0022) compared with 8H (-0.0028). This is despite
the fact that 8H had more proppant
pumped per foot of lateral and had access
to a larger reservoir drainage volume because of the presence of a single well on
its left flank (6H has wells 8H and 4H
flanking it on either side). This indicates
better long-term productivity and a lower
decline rate for Well 6H thanks to a potentially larger stimulated reservoir volume
per foot of lateral available.
By inducing a rapid rate change that
could lead to significant pressure pulses
capable of opening perforations and increasing the complexity of the induced
fracture network, the variable-rate design
increased production from odd stages by
double digits on a percentage basis in
the Marcellus study well. Based on these
encouraging results, additional experiments
are planned, including fracturing an entire
Permian Basin horizontal well from toe
to heel with a variable-rate treatment.
This next step in developing and testing
the method will incorporate more aggressive rate changes engineered specifically to accommodate Permian completion
designs, and implement the variable-rate
design in all frac stages in a horizontal
well. In addition, the completion will
add diagnostic instrumentation to determine fracture geometry and individual

stage production with microseismic monitoring, production logging, and fluid and
radioactive tracer data.
r
Editor's Note: The co-authors acJORDAN CIEZOBKA is a senior engineer at the Gas Technology Institute,
focused on hydraulic fracturing research
and other stimulation techniques. He
started his career as a field engineer
with a major oil field service company,
and has experience in designing and
executing hydraulic fractures in many
unconventional formations, including
tight sands and shales. Ciezobka holds
a B.S. in mechanical engineering and
a minor in electrical engineering from
Purdue University.
DEBOTYAM MAITY is a principal
engineer, exploration and production,
at the Gas Technology Institute. His
work focuses on research related to
geophysics and production engineering
in shale gas plays, including analyzing
and optimizing hydraulic fracturing

knowledge the Research Partnership to
Secure Energy for America for providing
funding for the project, and WPX Energy
Inc. for providing substantial cost-sharing
data and wells of opportunity.
programs. He began his career as a
field operations and panel engineer at
Reliance Industries in India. Maity
holds a bachelor's in chemical engineering from R.V. College of Engineering,
and an M.S. and a Ph.D. in petroleum
engineering from the University of
Southern California.
IRAJ SALEHI is a senior institute
scientist at the Gas Technology Institute.
An experienced geoscientist who has
served at GTI since 1985, he is well
versed in all aspects of upstream oil
and gas operations. His experience in
designing, constructing and operating
advanced laboratories led to the development of GTI's hydrates laboratory.
Salehi holds an M.S. in geophysics from
Stanford University.

Coming In September
Well Logging & Formation Evaluation reports, spotlighting state-ofthe-art neutron logging to find
bypassed oil reserves, advanced
geosteering methods for pinpoint
horizontal drilling accuracy, and new
acoustic logging and processing
methods to delineate pay structures.
AUGUST 2016 67

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American Oil and Gas Reporter - August 2016

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