American Oil and Gas Reporter - April 2022 - 57

SpecialReport: Logging-While-Tripping
the laterals logged, as shown in Figures 3
and 4. The signature of this signal is interpreted
as an indication of both longitudinal
and transverse fracturing observed near
the wellbore. The fracturing signal differences
observed for individual stages in the
same wellbore are believed to be facies,
cement quality, and structurally related.
The blue curve shaded in yellow (Track
8) in Figure 3 is the frac water saturation
curve derived from the case-hole and openhole
neutron log comparison. For this
stage (29), a longitudinal fracture behavior
was interpreted from the signal since the
curve was continuous throughout the stage.
A heel bias was observed with more fluid
present at the top of the image.
In Figure 4, variable cement density
is indicated in the curve to the right of
the depth track. The frac water saturation
curve was interpreted to indicate primarily
transverse fracture behavior with more
than 10 fracture amplitudes resulting from
the seven clusters.
Amplitude peaks indicating transverse
fracturing observed were often off-center
with the reported perforation locations.
This was either a matter of fracture
fluid movement behind pipe (and fracture
initiation then established) or the perforation
locations were off depth, or
possibly a combination of these two
factors. The double-amplitude peaks observed
in this stage are indicative of
DTS " warm back " signatures.
Optimizing Frac Treatments
To optimize frac treatment effectiveness,
the oil and gas industry must have
more fracture diagnostic measurements
taken more often. The NWR's influence
on SDE and fracture complexity needs
to be better understood and anticipated.
The combination of different diagnostic
measurement solutions can lead to interesting
discoveries as each of these technologies
approach PCE from different
measurements. Log-based PCE mathematically
correlates to permanent fiber
obtained DAS recordings, which is considered
the current gold standard for PCE.
LWT, by nature, is operationally friendly
and requires no changes to the field completion
strategy. Diagnostics for fracturing
need to be more common and tailored to
individual plays and basins. Economic and
operationally friendly fracture diagnostics
are necessary for the continued improvement
of fracturing operations and performance.
Diagnostic measurements need to be made
more attainable and tethered to wellbore
descriptions so that discrete fracture behavior
can be anticipated, and diagnostic measurements
can better impact decision-making
moving forward. When differences in fracture
behavior are observed from cluster to
cluster and from stage to stage, NWR and
structural drivers can be investigated with
conventional logging measurements.
Fracturing water saturation measurements
can give critical fracture geometry
insights into the NWR of horizontal wells.
This fracture behavior can help in reservoir
simulation practices and in determining
the extent of the fracture network. A
NWR stimulated reservoir volume (SRV)
can be quantified and compared for each
fracturing stage, although further work is
needed to understand the NWR SRV and
the impact of NWR properties on SRV as
well as production results. Differences in
fracture behavior can be indexed through
acquisition of well log data.
With the near-wellbore properties derived
and cement density mapped, some
of the reasons for this fracture behavior
can be determined and be made actionable
for future wells.
❒
Editor's Note: The authors acknowledge
the technical contributions of Cordax
Evaluation Technologies' Maarten Propper,
Wei Jiang, Jeff Jia, and Robert Hawkes.
For more information, see SPE 209130,
a technical paper originally prepared for
presentation at the Society of Petroleum
Engineers Hydraulic Fracturing Technology
Conference & Exhibition, held Feb.
1-3 in The Woodlands, Tx.
JESSICA
BARHAUG
Jessica Barhaug is a senior reservoir engineer at Great Western Oil & Gas Company in Denver,
where her responsibilities include managing D-J Basin completion optimization projects.
Before joining Great Western in 2019, Barhaug was a senior reservoir engineer at the Enhanced
Oil Recovery Institute in Casper, Wy. Prior to that, she had served as a senior completions engineer
at WPX Energy and as a production stimulation engineer at Schlumberger. Barhaug
holds a B.S. in engineering with an environmental specialty and an M.S. in petroleum engineering
from the Colorado School of Mines.
DARBY
WITT
Darby Witt is a completions technology specialist with Calgary-based Cordax Evaluation
Technologies. He supports the impact and investigation of the near-wellbore region on hydraulic
fracturing treatments. With 25 years of hydraulic fracturing experience, Witt has provided realtime
fracture pressure monitoring, evaluation, design and post-fracture analysis in both unconventional
and conventional onshore and offshore reservoirs worldwide. He holds a degree in
mechanical engineering from the University of Oklahoma.
APRIL 2022 57

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