American Oil and Gas Reporter - June 2024 - 50

SpecialReport: Artificial Lift Technology
ESPs Excel In Lifting Water,
Restoring Production
Following Frac Hits
By Marian Perez Salazar
LUBBOCK, TX.-Oil and gas companies
have devoted significant efforts to
minimizing the impacts of hydraulic fracturing
hits in horizontal resource play
development strategies as activity has
progressively shifted to infill locations
with longer laterals. Considerable knowledge
has been gained over the years in
understanding how stimulation fluids and
pressures can interact with one or more
adjacent wells during active frac treatments,
including several methods to protect
offset wells from both short- and longterm
interference.
However, should a well be impacted
by a fracturing operation on an adjacent
well or pad, what is the best course of
action to restore production as quickly
as possible? A Texas Tech University research
study analyzed the repercussions
of a frac hit on a well's operational parameters,
with an emphasis on the comparative
effectiveness of employing optimized
artificial lift techniques following
a frac hit to facilitate a rapid recovery in
well performance.
FIGURE 1
Parent Well Casing Pressure versus
Child Well Surface Treating Pressure (Woodford Shale)
14,000
12,000
10,000
8,000
6,000
4,000
2,000
5,000
4,500
4,000
3,500
3,000
2,500
2,000
1,500
1,000
500
Recognizing artificial lift systems are
not universally applicable across all wells
given the diversity in well characteristics
and reservoir conditions in shale plays,
the scope of the analysis was narrowed
to wells using electric submersible pumps
and gas lift-both of which facilitate
high rates of fluid extraction-to establish
a comparative framework for evaluating
lift efficiencies in the context of frac hits.
Moreover, the research focused on individual
wells situated in parallel configurations
to exclude the complexities introduced
by multiwell pads and provide a
clearer understanding of the direct impacts
of frac hits and the subsequent recovery
strategies using artificial lift systems.
Common Mitigation Practice
One of the most common frac hit mitigation
practices is shutting in an offset
well during nearby new well completion
activities as a precautionary measure.
However, when a shut-in well is brought
back into production, it may perform
quite differently than it did before shutting
in. This could be the result of several
factors, including:
· Pressure variations (pressure
changes sometimes can be beneficial and
enhance oil recovery, but they also can
be detrimental and reduce flow rates or
create unexpected pressure conditions);
· Interwell communication through
fractures (if the created fracture network
connects adjacent wellbores, it is possible
for the fluids to intermingle and lead to
cross-contamination or production
changes); and
· Frac fluid migration (fluids injected
during the fracturing process can migrate
to adjacent wellbores, altering reservoir
fluid composition and properties and affecting
flow characteristics and production
rates).
Figure 1 shows an increase in pressure
in a Woodford Shale parent well (Well
A) that was shut in while an adjacent
offset child well (Well B) was being hydraulically
fractured. The well was opened
after the fourth stage of the child well's
completion.
Overall, frac hits tend to negatively
impact the performance of wells in liquid-rich
reservoirs, particularly as a well's
natural reservoir pressure decreases over
time. After being shut in because of a frac
hit, wells often experience a rapid drop in
oil and gas production followed by a
gradual recovery period. Although this
pattern can vary by region, water output
tends to spike immediately after a hit and
then decrease as the well stabilizes.
In areas with an underlying brine formation,
a frac hit can also increase brine
production in the impacted well and any
others it connects with. The financial
consequences of such bottom-water hits
hinge on several factors, including the
ability of the fractures to seal over time
and the presence of a driving force from
the underlying water.
WDFD Well B, Surface Treating Pressure, Stages 1-19
WDFD Well A, Casing Pressure
Source: SPE 187192 (George E. King, et. al., 2017)
50 THE AMERICAN OIL & GAS REPORTER
Production Trajectory
Figure 2 shows a parent well's production
trajectory before and after an adjacent
child well's completion. The depicted
production curve incorporates a
phase during which the parent well was
" Child " Well Surface Treating Pressure, psi
" Parent " Well Casing Pressure, psi
4/05/2016
4/06/2016
4/07/2016
4/08/2016
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4/13/2016
American Oil and Gas Reporter - June 2024

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