American Oil and Gas Reporter - September 2017 - 27

Rock Fabric Awareness
Can Make A Big Difference
To Improve Completions
In July, the U.S. Energy Information Administration released
a forecast for U.S. shale production that projected it would rise
by almost 120,000 barrels a day. It also reported the ninth consecutive monthly rise. According to Reuters, this forecast
includes the Anadarko region, where the rig count is second
only to the Permian Basin.
Unconventionals, specifically shale oil, continue to pay a
significant role in our industry as we move toward 2020 and
beyond. One strategy EIA credits for these operations' success,
even during uncertain economic times, is the use of improved
drilling and completion technologies that aim at optimization
and efficiency.
In July, I attended the Unconventional Resources Technology
Conference in Austin, Tx. This growing event is put on annually
by a partnership among the Society of Petroleum Engineers, the
American Association of Petroleum Geologists and the Society
of Exploration Geophysicists. The event draws more than 2,500
individuals and is founded on the premise that shale plays
continue to hold a significant place in the world's energy future.
Not surprisingly, between technical papers and the robust
tradeshow, innovations in unconventional oil and gas exploration,
drilling and production could be found everywhere.
One of the more interesting aspects of this event is how it
successfully merges engineers, geologists and geophysicists
into the same show. Getting these groups into the same room
for three days helps to better link these disciplines that depend
on each other in the industry. One URTeC paper in particular
caught my attention and illustrated the link between geoscience
and engineering. Titled, "Constructing High Resolution, Inch
Scale Continuous Logs via Multi Domain Approach to Improve
Hydraulic Fracturing by Capturing Thin Beds in the Bone
Springs Formation, Delaware Basin, Reeves County, Tx.
(URTeC: 2670758)" by Santhosh Narasimhan, Pukar Mainali,
Harry Rowe, Austin Morrell, Wesley Ingram, Andy Benson,
Nathan Ganser and Sean Arrington from Premier Oilfield Laboratories, this paper explores the importance of understanding
rock fabric and its implications for hydraulic fracturing.
The authors review the importance of developing and creating
cost-effective production in shale plays. This is not a new idea.
For many years, technological innovations have been developed
and employed to optimize completions. Typically, these innovations come in the form of equipment or operational improvements. However, these authors assert that fine-scale reservoir
characterization derived from high-resolution core data can improve completions dramatically, although it is often underutilized.
To show how integrating these properties can improve a
fracture propagation model, the authors created and analyzed
high-resolution continuous logs from core analysis in the Bone
Springs. They began with one-inch, high-resolution core measurements using X-ray fluorescence (XRF) and one-foot X-ray
diffraction (XRD) scales.
XRF works simply by shooting an X-ray into a sample of
core. This beam reacts with the core's atoms, helping researchers

"For the Delaware Basin, it became clear that
the high layering effects must be characterized
to adequately optimize the frac geometry for

proper reservoir engineering applications.

identify chemical signatures within the sample that are analyzed
to help determine core composition. This determination, in
turn, can help evaluate the rock's geomechanics.
Similarly, XRD analysis helps scientists identify core samples
and cuttings based on the structure of crystals within the sample.
During the process, each sample gives off a unique pattern of
diffraction, allowing it to be compared with other well-known
patterns and helping to identify the sample properly, again with
the goal of using this data to evaluate the reservoir and design
optimal frac models.
In this case, the authors suggest standard logs simply cannot
achieve resolution sufficient to address thin bed layering effects
adequately. The small, one-inch scale features can impact
fracture and production modeling dramatically. In an effort to
identify and evaluate the region's thin beds, researchers developed
a suite of tests to capture the small changes between the geochemistry of the cores, helping to profile each layer.
The paper's authors concluded that the log-based models
from standard sonic log resolution were inferior to those that
were rationalized by integrating geochemistry to capture the
thin bed effects. The authors found that a multi-domain integrated
approach that included logs and high-resolution models illustrated
the importance of multiple thin beds and the impact on the hydraulic fracturing workflow. For the Delaware Basin, it became
clear that the high layering effects must be characterized to adequately optimize the frac geometry for proper reservoir engineering applications. Overall, the high-resolution chemostratigraphic core measurements in this region were essential to an
optimized completion process.
As unconventional exploration and production continue to
grow our industry, it is essential to evaluate every opportunity
to find efficiencies and optimization workflows. As events
such as URTeC continue to bring multiple disciplines together,
these innovations will continue to occur as geology, engineering
combine to develop innovation.
r

JEREMY VISCOMI is the MidContinent regional lead for
the Petroleum Technology
Transfer Council. He has more
than a decade of experience
in developing and organizing
technical conferences and special events, primarily in the
oil and gas industry.
SEPTEMBER 2017 27

American Oil and Gas Reporter - September 2017

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