American Oil and Gas Reporter - August 2018 - 56

SpecialReport: Horizontal Wellbore Construction

Sycamore Well Nets Impressive Results
By James Jackson,
James Calvin
and Brandon Drake

in Grady and Stephens counties, most
of them were completed prior to 2000.
Several attributes can be noted from
these studies, however. For instance,
reported porosities were between 3 and
20 percent in target intervals, and matrix
permeabilities were in the millidarcy
and microdarcy ranges. Cores analyzed
displayed evidence of natural fracturing
that were classified as open, partially
open, healed or calcite-filled. Image
logs from the studies also showed signs
of fracturing.
With operators beginning to look at
the Sycamore as a potential horizontal
drilling target, it is important to develop a
better understanding of the reservoir in
order to apply appropriate technologies
to effectively complete wells drilled in
the formation. By thoroughly analyzing
the previous studies conducted in the area
and gathering data about the formation,
Ward Petroleum has formulated an appropriate treatment design that is both reflective of current SCOOP/STACK completion practices and incorporates advanced
technologies such as microproppant and
biodegradable diverting agents to effectively
stimulate the Sycamore.
Ward Petroleum's first application
of the treatment design was in a horizontal well targeting the lower bench
of the Sycamore formation within the
SCOOP play area in Grady County. The
well's production results are among the
best in the area, demonstrating the potential of applying modern horizontal
drilling and hydraulic fracturing tech-

OKLAHOMA CITY-The Meramec
and Woodford Shale formations have
been the focal points of drilling activity
in the SCOOP and STACK plays in the
Anadarko Basin. However, as development
continues across the basin, operators are
targeting additional formations, such as
the Sycamore, which has seen only limited
development in recent years.
Located below the Caney Shale and
above the Woodford Shale, the Sycamore
is present in the southern part of the
Anadarko-including across a significant
portion of the SCOOP play-and extends
south into the Ardmore Basin. It is analogous to the Meramec and Osage formations in the STACK play in that all three
are of Mississippian age and contain liquids-rich reserves.
The Sycamore has variable lithology,
with both calcareous and siliceous attributes. It can be divided into four primary
benches separated by shale facies: an
upper bench (top layer), a middle shale
(first middle layer), a lower bench (second
middle layer), and a base shale. The
upper and lower benches are assumed to
be the productive intervals. The reservoir
can range from retrograde condensate to
a volatile oil reservoir with liquid hydrocarbon API gravities ranging between 40
and 60 degrees.
Although petrophysical studies have
been conducted in the area of interest

niques to a largely unexploited and overlooked formation.
Treatment Design
Ward Petroleum's Grady County well
was the first horizontal to be drilled in
the Sycamore formation in the immediate
area. The left-hand map in Figure 1
shows the boundaries of the Sycamore
formation as well as the SCOOP and
STACK plays. The right-hand map shows
the location of the Grady County horizontal in relation to other horizontal and
vertical wells previously completed in
the Sycamore. The well's lateral length
is 7,576 feet with a total measured depth
of 22,430 feet and a true vertical depth
of 14,400 feet. The lateral construction
plan consisted of 31 stages.
The two primary focuses of the stimulation design were to improve nearwellbore (NWB) conductivity and exploit
any fracture complexity inherent in the
treatment zone. Because no definitive
measurement of closure stress in the area
was available, historical data were used
to approximate potential closure pressures
using fracture gradients of 0.50-1.05
psi/foot. These gradients from previous
wells drilled in the Sycamore formation
in Grady and Stephens counties were
used as a starting point for the anticipated
closure pressure.
Based on available core data and
studies conducted in the SCOOP area in
the Sycamore formation, some degree of
complexity appeared to exist, making it
imperative to structure the design to both

FIGURE 1
Regional Map (Left) and Area Map (Right) Showing New Sycamore Well and Existing Wells
Vertical wells
Horizontal wells

STACK
Anadarko Basin

Grady
Well of interest

McClain

Sycamore
Ardmore Basin

Garvin

SCOOP
Stephens

56 THE AMERICAN OIL & GAS REPORTER

American Oil and Gas Reporter - August 2018

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