American Oil and Gas Reporter - June 2023 - 41

AOGR Chemistry Special: Polymer Gel Apps
Today's Treatments
Enhance Well Economics,
Optimize IOR/EOR Projects
By Randy Prater, Daniel French and Mehdi Salehi
PLAINVILLE, KS.-The use of polymer gel technology, while
sometimes overlooked, is an effective means to improve economics
and help overcome various challenges that can pop up in new and
mature producing wells. Polymer gel aids in waterflood applications,
but has also been used to aid in water shutoff with its ability to
reduce reservoir permeability and eliminate casing leaks without
the expense of a packer, patch or squeeze job. However, polymer
gel's ability to improve conformance makes this technology an
integral part of a long-term production strategy.
The success of a secondary recovery or waterflood project
depends on the method by which the injected fluid displaces the
oil (displacement efficiency) and the volume of the reservoir
that is contacted by the injected fluid (sweep efficiency). In the
early 1960s, it was realized that blocking or plugging materials
could be used to divert water from high-permeability flow
channels into lower-permeability rock.
Hence, cross-linked bulk gel systems were developed and
designed for near-wellbore problems related to water encroachment
in producing wells and channeling of water out-of-zone in
injectors. The former application of polymer gel systems is
called a water shutoff application designed to address excess
water production, and the latter typically is referred to as conformance
and profile modification application designed to
address reservoir heterogeneity. Bulk gel chemistry is robust
and can be used in most waters and relatively high temperatures
(<300 degrees Fahrenheit).
Water shutoff operations are designed to target the influx of
water production through coning or channeling due to geological
anomalies such as vugs, natural fractures or permeability contrast.
During the process, gelant is injected into the reservoir at a rate
under frac gradient targeting zones that contribute to significant
water volumes. The gel forms under temperature, blocking water
and modifying the drainage pattern to the wellbore in favor of increased
oil production. Typical treatments result in as much as a
90% reduction in water and a 20%-30% increase in daily oil
rates, to as much as a 1,000% increase in oil production after
treatment. Additional benefits include reduced expenses for high
water production volumes, such as electricity and chemical costs.
Conformance Treatments
Conformance/profile modification targets inefficient flood
patterns to improve oil production by redirecting injection fluid
to lower-permeability or tighter unswept portions of the reservoir.
Conformance treatments address high-permeability streaks
known as thief zones by blocking these areas deep into the
reservoir, forcing the injection fluid around the gel block into
tighter, oil-saturated rock. This results in the mobilization of
bypassed oil to offset production wells, often resulting in significantly
increased reserve recovery. Profile modification treatments
address injection profile inefficiencies by directing
injection fluids more proportionally when multiple zones are
open. In many cases, the majority of fluid favors one or two intervals.
As a result, injection fluid is forced into neglected
intervals to increase oil production.
JUNE 2023 41
American Oil and Gas Reporter - June 2023

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