American Oil and Gas Reporter - August 2019 - 101

SpecialReport: Hydraulic Fracturing Technology
of choice for future full-lateral refracturing.
Wells with modern completion techniques in the same producing formation
in this area are outperforming the wells
drilled several years ago. The results of
these refractured wells are similar to the
newer wells.
Although there was no major difference
in peak rate production of the original
frac and peak rate after the refrac of Candidate No. 1, there was considerable difference in the decline curve before and
after refracturing (at left in Figure 2).
Production before the refrac exhibited a
very steep decline, which was attributed
to the limited reservoir contact area. However, when comparing the before and
after production profiles, the forecasted
EUR almost tripled and ROR of the
project increased more than 100%.
On Candidate No. 2, there was little
difference between initial production rates
of the original completion and after the
refrac, but forecast EUR doubled. The
economics remained marginal, however,
because of the higher costs incurred when
refracturing the well. An increase in production was observed when optimizing
artificial lift. Pre- and post-refrac decline
curves are shown at right in Figure 2.
Initial production after refracturing
Candidate 3 was double the original completion and forecast EUR almost tripled
while the rate of return was over 100%
(at left in Figure 3).
On Candidate 4, the initial production
after refracturing increased 10-fold compared with the original IP and forecast
EUR almost tripled (at right in Figure
3). Early evaluation of the production
profiles before and after the refrac shows
that the rate of return increased by more
than 60%.
Based on the successful refracturing
operations, which resulted in increased
recovery, Oxy is considering additional
refracturing of other understimulated
wells in the Bone Spring formation in its
New Mexico Permian Basin acreage. The
four-well trial project shows that fulllateral refracturing with tighter cluster
spacing and higher proppant concentrations
than vintage designs can enhance SRVs
to significantly increase production and
unlock unrecovered reserves at a lower
cost than newly drilled wells. Moreover,
well economics and operational efficiencies can be optimized by scheduling several refrac candidates consecutively and
utilizing existing facilities with minimal
upgrades to accommodate revitalized production from refractured older wells. r

FIGURE 2
Decline Curve Analyses of Candidate 1 (Left)
And Candidate 2 (Right) Wells

Pre-Refrac

Post-Refrac

Pre-Refrac

Post-Refrac

FIGURE 3
Decline Curve Analyses of Candidate 3 (Left)
And Candidate 4 (Right) Wells

Pre-Refrac

Post-Refrac

AMRUT ATHAVALE is a completions
engineering supervisor at Oxy, where
he is responsible for planning and executing completions operations in the
Midland and Delaware sub-basins. He
joined Oxy in 2011 as a drilling engineering adviser and drilling engineering
supervisor. Prior to that, Athavale had
served as petroleum engineer at Hess
Corp. and Reliance Industries Ltd. He
holds a B.S. in petroleum engineering
from Maharashtra Institute of Technology,
an M.S. in petroleum engineering from
the Colorado School of Mines, and an
M.B.A. from the University of Houston.
ADEBAYO ONAFOWOKAN is a
completions adviser at Oxy. Before joining the company in 2011, he was a
stimulation specialist at Abu Dhabi National Oil Company, a staff completions
engineer at ConocoPhillips, and a production solutions and field engineer at
Schlumberger. Onafowokan has a B.S.
in petroleum engineering from the University of Ibadan and an M.S. in petroleum engineering from the University
of Houston.
CARL KASDANO is a completion
engineer at Oxy. Before joining the company in 2015, he was a completion engineer in the Eagle Ford at ConocoPhillips
and a completion engineer in the San
Juan Basin at Range Resources. Kasdano

Pre-Refrac

Post-Refrac

holds a B.S. in petroleum engineering
from Pennsylvania State University.
SUNIL LAKSHMINARAYANAN is
reservoir engineer adviser in Oxy's New
Mexico business unit. Before joining
Oxy in 2014 as a senior reservoir engineer in the Williston Basin, he served
for eight years at Weatherford as a
reservoir engineering senior geoscientist/project manager, R&D reservoir engineer, and an underbalanced/managed
pressure drilling reservoir engineer.
Lakshminarayanan holds a B.S. in chemical engineering from the University of
Madras and an M.S. in petroleum and
natural gas engineering from West Virginia University.
LISSET SOUSA is senior adviser
for reservoir engineering at Oxy, working
in the New Mexico Permian Basin.
Before joining Oxy in 2017, Sousa
served in multiple roles at
Statoil/Equinor, including as manager
of nonoperated Bakken and Eagle Ford
assets, reservoir engineer team lead
and principal reservoir engineer for
U.S. onshore unconventional assets.
Prior to that, she has served in reservoir
engineering roles at Halliburton and
Chevron. Sousa has a bachelor's in petroleum engineering and a master's in
gas engineering from the Universidad
del Zulia.
AUGUST 2019 101

American Oil and Gas Reporter - August 2019

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