American Oil and Gas Reporter - November 2016 - 45

SpecialReport: Oil & Gas Computing
in the model.
In the model, the stress shadowing
behavior dominates fracture geometry
and pushes fracture growth toward the
heel, while the actual well is experiencing
both stress shadowing behavior and perforation connectivity.
Such behavior may explain why "engineered completions" based on the need
for efficient well/reservoir connections do
not always result in production enhancement
over equally staged perforation clusters.
Several stages had perforation clusters
spaced approximately two times the distance between the other perforation clusters
in the stage. In general, these perf clusters
most likely were associated with dominant
fractures during the stage. This observation
suggests that when perforation clusters
are located too close, the fractures experience difficulty in breaking down initially,
and even if they do, so much stress shadowing is present that the final result is a
highly ineffective fracture.
Some of the most interesting outcomes
of the project were the responses experienced
during diverter application. While the treatments were being pumped, surface pressure
responses were as expected, (i.e., a pressure
increase when the diverter reached perforations). However, as observed by
DAS/DTS, frequently an appreciable diversion of treatment was not accomplished.
Such unexpected behavior is not a reason
to eliminate the use of diverters. However,
it does point to the importance of techniques
and methods for pumping diverters. Moreover, dropping the rate while pumping diverters should be evaluated carefully. Several
instances were noted during fracture modeling when the model approached screenout conditions during rate reductions associated with diverter placement.
In general, the DAS/DTS data acquired
on this project illuminated some of the inefficiencies that are inherent in plug-andperf completions. Large gaps can exist
between clusters in any given stage, and
the possible creation of only one effective,
contributing fracture in a given stage can
have a major impact on reserves recovery
and the overall drainage profile of a well.
Obviously, the potential for this inefficiency was realized prior to the well's
completion, since efforts were made to
divert the treatments into other clusters.
However, in this well, such efforts did
not completely fulfill expectations. Additional solutions must continue to be
sought.
r

FIGURE 6B
Proppant Concentration Distributions
For Dominant Cluster 3 of Stage 4

BILL WHEATON provides completion
and reservoir engineering advisory services through Wheaton Consulting USA,
focused primarily on shale and other
unconventional resource plays. With more
than 30 years of experience in South
Texas, the Mid-Continent, Fort Worth
Basin and Central Texas, he previously
served as senior adviser, operations engineering, for Devon Energy Corporation.
Wheaton holds a B.S. in chemical engineering from Texas A&M University.
KYLE HAUSTVEIT is a completions
engineer at Devon Energy, focused on
fracture modeling, diagnostic fracture
injection test evaluations, and data
gathering techniques in the Eagle Ford
and STACK plays. He joined Devon in
2013 as a production engineer. Haustveit
holds a B.S. in petroleum engineering
from Montana Tech.
WOLFGANG DEEG is a senior engineering adviser at Devon Energy.
Prior to joining Devon, he served as a
staff production engineer for Shell International Exploration & Production
Company. Deeg holds a B.S. in mechanical engineering and a B.A. in
mathematics from the University of
Connecticut, an M.S. in materials science

from the California Institute of Technology, and a Ph.D. in materials science
from Stanford University.
JENNIFER L. MISKIMINS is an associate professor and assistant department head in the petroleum engineering
department at the Colorado School of
Mines. Her interests include stimulation
and hydraulic fracturing, well completion, rock mechanics, unconventional
reservoirs, multidisciplinary research,
economics, and property evaluation.
She holds a B.S. from Montana College
of Mineral Science & Technology, and
an M.S. and a Ph.D. from the Colorado
School of Mines, all in petroleum engineering.
ROBERT D. BARREE is president
and principal investigator of Barree &
Associates. He has been involved in
developing hydraulic fracture technology
since 1980 and is the primary author
of the fully 3-D hydraulic fracture simulator, GOHFER. Barree served as an
SPE distinguished lecturer on the topic
of new philosophies in hydraulic fracturing. He holds a B.S. in petroleum
engineering from Pennsylvania State
University and a Ph.D. from Colorado
School of Mines.
NOVEMBER 2016 45

American Oil and Gas Reporter - November 2016

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