A research report by the University of Aberdeen on the GLENSOL Oil Remediation Additive - Evaluation of GEOR 1 as an Additive for Enhanced Oil Recovery

1. Evaluation of GEOR 1 as
an Additive for Enhanced
Oil Recovery
Prepared by:
Professor Andrew Hurst
Dr Stephen Bowden
Dept Geology and Petroleum
Geology,
University of Aberdeen,
Aberdeen
Scotland
06 July 2009

2. Evaluation of GEOR 1 for EOR
Page
Summary 2
Introduction 6
Experimental Method 10
Results
Recovery Efficiency 13
Fractional Flow analysis 17
Notes on Areal Sweep efficiency 21
Conclusion 23
Abbreviations
cp; centipoises
EOR; Enhanced oil Recovery
GEOR 1; Glensol mixture used for experiments
HO; heavy oil
M; mobility ratio
1

3. Evaluation of GEOR 1 for EOR
Summary
Water flooding with GEOR 1 significantly enhances recovery of heavy oil. The
presence of a low concentration (5 parts per million) increases the amount of oil
recovered and reduces watercut. Relative to flooding with coldwater (20 deg C)
or hotwater (>85 °C) flooding with GEOR 1 brings forward production of heavy
oil.
A single GEOR 1 additive is effective for both saltwater and freshwater. Many
surfactants and emulsifying agents achieve very high levels of oil recovery but
GEOR 1’s efficiency at low concentrations and in both salt- and freshwater set it
apart. These two distinguishing features suggest the potential to succeed in the
field where other chemical methods of enhanced oil recovery have failed.
Previous chemical methods of enhanced oil recovery have depended on
laboratory studies to adjust and optimise surfactant solutions prior to field
application. GEOR 1’s efficiency at low concentrations combined with its
improved economic efficiency would help to mitigate the marginal nature of
chemical EOR methods: e.g. surfactant loss would be less significant
economically and should increasing the concentration of GEOR 1 to improve
recovery be necessary this need not significantly impact project-margins.
Results for preliminary coreflood experiments are summarised in Table 1.1 and
1.2. During all experiments a flood with coldwater (20 deg C) was performed to
drive a ~10000 cp heavy oil from a beadpack (the primary oil recovery phase).
Subsequent to this an EOR method is applied (flooding with GEOR 1or hotwater
or an extended flood with coldwater). The EOR phase was extended by flooding
with an equal pore volume. For both cold- and saltwater, enhanced oil recovery
by flooding with GEOR 1 greatly increased oil recovery and reduced watercut
relative to continued flooding with coldwater. Increases in oil recovery and
reductions in watercut achieved by GEOR 1 compare favourably or exceeded
those of hot water.
2

4. Evaluation of GEOR 1 for EOR
Images of the beadpack before and after flooding with GEOR 1 in Table 1.1 and
1.2 show the recovery of oil from bypassed regions. Relative to other methods
GEOR 1 appeared efficient at accessing zones of bypassed oil. GEOR 1 was
originally developed to remove heavy oil residues to remediate contaminated
land and clean surfaces. In this application GEOR 1 acts rapidly, penetrating
asphaltic deposits to clean oil from surfaces. This ability appears to transfer to a
dynamic environment at the laboratory-scale, and would be crucial at the field
scale if it improved the access of an EOR fluid to oil bypassed by the initial water
flood.
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5. Evaluation of GEOR 1 for EOR
Table 1 Summary of results
Oil Watercut during
Recovered† EOR‡
% Image before
Image after EOR
Reduction
EOR EOR phase
Extended
Average
Primary
Lowest
†† phase
EOR
‡‡
Freshwater
37
33 70 93 (55) 64 67 -10
GEOR 1
5 μL/L
27 67 90 40 60 67 -15
(60)
10
27 37 (30) 80 82 +5
Coldwater 55
27 43 16 85 85 +11
(37)
27 40 – 13 65 85 -28
Hotwater
>70 ºC
80 – 85 ºC 46 – 64 78 -28
16
Hotwater 36 -38
63 – 55 71
85 ºC (57) -10
4

6. Evaluation of GEOR 1 for EOR
Table 1 Continued
Oil Watercut
Recovered† during EOR‡
Image before Image after EOR
Reduction
Extended
Average
Primary
Lowest
% EOR phase‡‡ phase
EOR
EOR
††
Saltwater
GEOR 1
35 72 83 37 40 51 -31
5 μL/L (54)
Coldwater 40 50 10 50 66 +27
(20)
†
Oil Recovered = the % of oil initially in place recovered. Primary recovery = % recovered after
waterdrive; EOR = % recovered after equal volume of water to primary phase used to implement EOR
technique; Extended = % recovered after extension of EOR phase. Approximately equal pore volumes used
for each experiment.
††
% EOR = % of oil initially in place recovered by first EOR technique, number in brackets is %
enchantment in oil recovery.
‡ Water cut during EOR . Note that for extended flooding there is no reduction, hence this number is
positive.
‡‡ Water is entering from the top of the page and oil exiting from wells at the bottom. Coloured lines
identify regions of different shading, where shading is being used as a proxy for oil saturation. Blue is
highest saturation and yellow lowest.
5

7. Evaluation of GEOR 1 for EOR
1.1 Introduction, aims and objectives
Experiments were designed and conducted to test under laboratory conditions
whether there is evidence that GEOR 1, a chemical additive, has the potential to
enhance the direct recovery of heavy oil from reservoir rocks. The background for
the experimental work is a history of successful applications of GEOR 1 to
dispersal of heavy-oil pollution, remediation of oil-contaminated sand and
cleaning and unblocking of oil transport infrastructure (pipelines and storage
tanks). The success of these downstream applications coupled with their cost
effectiveness and environmental friendliness encouraged Glensol, the
manufacturers of GEOR 1, to evaluate possible use of the additive to enhance oil
recovery from natural reservoir rocks. GEOR 1 was successfully tested by
Glensol as an extraction method for mined and quarried tar and oil sands. If
significant improvement in heavy-oil recovery is possible by using a chemical
additive it opens the way for step changes in the recovery of heavy oil both in
terms of recovery efficiency and cost per barrel of oil recovered.
The aim of this study is use simple laboratory experiments to verify that a low
concentration of GEOR 1 added to water can enhance the recovery of heavy oil
from reservoirs. Recovering heavy oil from the subsurface in a dynamic
environment is very different to extracting bitumen from sand at the surface.
Therefore specific objectives are required to benchmark any enhancement in
recovery observed for GEOR 1 compared to extended flooding with coldwater
and hotwater, with particular attention being paid to factors unique to flow through
porous media. These factors are the rate of oil recovery relative to chosen
benchmarks, and how much water is produced along with a given volume of oil.
Additional objectives were to observe the behaviour of GEOR 1 in both salt and
freshwater systems and differentiate GEOR 1 from previous methods of
chemical-enhanced oil recovery.
Specific questions to answer are:
6

8. Evaluation of GEOR 1 for EOR
• Can GEOR 1 enhance oil recovery?
• Is GEOR 1 stable and effective in both fresh and salt water?
• How efficient is GEOR 1 in comparison to alternative methods of EOR?
• How does GEOR 1 improve upon other chemical methods of EOR?
Positive outcomes for the experiments above provide a basis for planning and
designing field tests of GEOR 1 in conventional heavy-oil reservoirs. The
experiments are designed to give oil-field operators a clear indication of the likely
benefit of using GEOR 1 in a commercial context.
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9. Evaluation of GEOR 1 for EOR
1.2 Previous chemical EOR
Although there is a considerable literature on chemicals that enhance oil recovery
there have been few successful commercial projects. General textbooks on
reservoir engineering tend to characterise chemical methods of enhanced oil
recovery as being economically marginal and technically complex, although
rarely for a common reason.
Foremost is that the cost of the surfactants can be expensive relative to the value
of any increase in oil recovery. This is further compounded by the possible loss of
surfactants to the reservoir formation during floods. Furthermore in many field
situations it has been difficult to bring the injected water containing EOR-
chemicals into contact with bypassed oil – the injected water containing EOR
chemicals simply flows around regions that contain residual oil.
Technical problems are caused the sensitivity of surfactant properties?? to
differing reservoir formation water chemistry and mineralogy, which necessitate a
design stage to specifically tailor a combination of surfactants and their co-
surfactants for particular reservoir characteristics. A miscalculation or false
assumption about reservoir rock and fluid properties at an early design stage has
the potential to cause failure for a chemical EOR project at the field scale.
Therefore in addition to the costs of implementing a field-scale EOR project a
considerable investment is also necessary at the design stage, thus a chemical
EOR project is inherently risky, may take along time to bring to fruition and even
longer to pay back a financial investment.
The chemical composition of GEOR 1 is confidential and thus it is hard to place
within the schemes typically used to characterise chemical EOR techniques.
Previous characterisations of EOR treatments similar to GEOR 1 include low and
high concentration surfactant floods, techniques that form surfactants using
chemicals already present in the oil (alkali flooding) and those that use
8

10. Evaluation of GEOR 1 for EOR
microbially produced biosurfactants. Although GEOR 1 is used at low
concentrations, and forms water in oil micro emulsions, the producers of GEOR 1
believe that GEOR 1 does not fit easily within any currently used classification.
9

11. Evaluation of GEOR 1 for EOR
2.0 Experimental method
A microfluidic beadpack was adapted to allow the preliminary evaluation of water
flooding with GEOR 1 as a method of enhanced oil recovery for heavy oil. During
experiments the bead-pack was flooded with heavy oil and to promote the aging
of the system to an oil-wet state it was warmed at 30 ºC. The device was cooled
to room temperature before use. Two or more phases of recovery were used.
The first phase comprised primary recovery by water drive. During this stage
coldwater (20 ºC) was used. Second and subsequent phases comprised flooding
by one of three techniques; 1) coldwater (20 ºC), 2) hotwater between 70 to 85
ºC or 3) water with a 5 μL/L (5 ppm) concentration of GEOR 1. The beadpack
was videoed during the experiments and still-images were point-counted to
measure water saturation and the volume of fluids exiting the bead pack. The
methodology is summarised in figure 2.1. Table 1 lists the experiments
performed for the evaluation of GEOR 1 as a heavy oil recovery additive and the
details of additional experiments whose results are presented here for evaluation
purposes.
Table 2.1 Experiments used for report
Water type EOR method Other details
Freshwater GEOR 1 5 μL/L concentration
GEOR 1 duplicate
Coldwater comparison
Hotwater comparison experiments at 70, 80 and 85 ºC
Saltwater GEOR 1 5 μL/L concentration
Coldwater comparison
Heavy Oil and Water
The oil used is from Siljian (Sweden) and has an asphaltene + resin content of 36
%, an API value of 18 o/ ~10 000 cp. Tap water (TDS < 500 mg/L) was used for
freshwater floods and seawater for saltwater floods (TDS ~ 35 000 mg/L). The
same stock solution of GEOR 1 was used to make up saltwater and freshwater
10

12. Evaluation of GEOR 1 for EOR
solutions of 5 ppm concentration. GEOR 1 was not explicitly tailored or adapted
for the heavy oil and bead pack used in this study.
1) Channel with 2) Channel packed with
bead trap beads
3) Oil flown into 4) Water flown into
channel channel
~ 48 μm
5) Volume of oil and water in draining Bead diameter/ Grain size: 22 μm
wells counted
Porosity: ~ 46 %
800 μm
6) Before and after images of gravel pack analysed
Figure 2.1 Photo graphs of device, and device before and after heavy oil is emplaced. Schematic diagram of
method, showing different stages of an experiment.
11

13. Evaluation of GEOR 1 for EOR
Further details
The device used in this study is not a micromodel but a micro-scale beadpack.
The key difference between the two techniques is that the beadpack creates true
3D tortuousity. The sodalime glass-beads used for experiments are a high
sphericity 22 micrometer diameter particle-size standard. Beads were introduced
through a channel 500 micrometers in breadth and ~46 micrometers in depth
until a pack of suitable length accumulated behind a gap filter. A picture of the
device and an image of the channel packed with beads is shown in figure 2.2.
Prior to use the pack was flushed with the water appropriate to the experiment
and the oil flown in to the pack at high flow rates/pressures. Prior to each
experiment the device was warmed to 30 oC to promote the adhering of oil onto
the beads to create an oil wet system.
During experiments the beadpack and the draining wells were videoed. Image
stills were point-counted to obtain water saturation and fractional watercut. When
measuring fractional water-cut, blocked-wells were excluded from calculation of
the parameter.
The device was fabricated at the James Watt-Nano Centre at the University of
Glasgow in cooperation with Professor Jonathan Cooper, experiments were
performed at the Dept of Geology and Petroleum, University of Aberdeen.
12

14. Evaluation of GEOR 1 for EOR
3.1 Heavy oil production using different EOR techniques
Fluid flow during experiments was driven by the circulation of water with the data
collected including the volume of water injected into the device, the percentage of
water in the beadpack and the percentage of water exiting through the draining
wells 1 . These three measurements represent the time taken to recover a given
quantity of oil, the amount of oil recovered out of the total available and the
proportion of oil recovered relative to water.
The amount of oil produced per volume of injected water is plotted in figures 3.1.
and 3.2. Extended phases of recovery are denoted by dashed lines, but the
following discussion refers to the first phase of enhanced oil recovery. Relative to
flooding with hotwater and coldwater, flooding with GEOR 1 brought forward
production significantly. This is illustrated in figures 3.1.and 3.2 by GEOR 1
attaining its maximum displacement of oil for the circulation of lower pore
volumes in comparison to the hot- and coldwater experiments. Although the
overall volume of oil displaced is similar for both hotwater and GEOR 1, the key
difference is that GEOR 1 attains this far more rapidly (a Welge displacement
efficiency calculation suggests that to recover 70 % of the oil initially in place
more than 50 pore volumes of cold-freshwater would have to be circulated).
Fractional water-cut is a measure of the proportion of water produced relative to
oil. Because of the viscous and asphaltic nature of the heavy oil used during the
experiments water is significantly more mobile than oil during the primary water-
flooding. This is particularly notable for the cold-freshwater experiment where the
watercut was very high from an early stage in the experiment (figure 3.3). This
continued during extended flooding with cold-freshwater. In contrast coldwater
flooding with GEOR 1 added significantly reduced or suppressed the fractional
water-cut.
1
The higher the amount of water in the bead pack the greater the amount of oil displaced and
recovered. Similarly; either water or oil is exiting the device so the greater the percentage of
water exiting the device the lesser the percentage of oil recovered.
13

15. Evaluation of GEOR 1 for EOR
1
0.8 Primary Recovery 5 ppm Glensol
Water saturation
0.6
Cold water
0.4
Hot water 85+ ºC
0.2
Hot water 75 to 80 ºC
0
1
0.8
5 ppm Glensol
0.6
Cold water
0.4
0.2
0
0 5 10 15 20 25 30 35 40 45 50
Pore volume injected subsequent to water break through
Figures 3.1 and 3.2. Graphs illustrating the recovery of oil by displacement with water. All unfilled
symbols e.g. □, ○ etc refer to data for primary recovery phases. Shades symbols: ■▲ = data obtained for
Glensol; ● = data obtained for cold water; + = data for hot water experiments. Dashed lines show extended
flooding with Glensol.
14

16. Evaluation of GEOR 1 for EOR
Making a comparison between the hotwater and GEOR 1 flood experiment is a
little more complicated due to differential changes in volume in the oil phase
brought about by the two EOR techniques. It is likely that the overall reduction in
water-cut brought about by GEOR 1 is at least equitable to that of the hotwater
method if not greater. The minimal water-cut values attained by both techniques
are about 60 % for the freshwater/heavy oil system (figure 3.3.).
The saltwater/heavy oil system exhibited higher recoveries of the oil in place. The
presence of saltwater changes how heavy oil interacts with solid surfaces
(lowering the contact angle between the oil and water phases on wetting
surfaces). For an oil-wet system the decrease in contact angle or wetting
preference in saltwater can increase the mobility of the oil phase causing it to be
more easily mobilised than in a freshwater/heavy oil system. The effect of this
change in wetting preference can be seen by comparing figure 3.1 and 3.2,
where considerably more oil is mobilised during flooding with saltwater than with
freshwater.
The behaviour of GEOR 1 in a saltwater system is important in two respects: 1)
does GEOR 1 have an effect above that of using cold-saltwater alone and 2) is
GEOR 1 stable in both a fresh and saltwater environment? Firstly; flooding with
GEOR 1 in a saltwater system brought forward production significantly and
recovered more oil than cold-saltwater alone, but most notably it reduced water-
cut by about 40 % (figure 3.4). Secondly, the same GEOR 1 batch enhanced oil
recovery in both freshwater and saltwater/ heavy oil systems. This is highly
significant because it broadens the scope of applicability for GEOR 1-flooding as
an EOR-technique. Previous surfactant flood and EOR techniques that utilised
micellar solutions have been highly sensitive to formation water chemistry
requiring a pre-flush to condition formations or the tailoring of surfactants for
specific formation water chemistries. For both salt- and freshwater a GEOR 1
flood recovered 70 % of the oil in place.
15

17. Evaluation of GEOR 1 for EOR
1
Hot water 75 to 80 ºC
0.8
Fractional water cut
0.6 Hot water 85+ ºC
5 ppm Glensol
0.4
0.2
0
1
0.8
0.6
0.4
0.2
0
0 5 10 15 20 25 30 35 40 45 50
Pore volume injected subsequent to water break through
Figure 3.3 and 3.4. Graph of the fraction of water exiting the device. All unfilled symbols e.g. □, ○ etc
refer to data for primary recovery phases. Shades symbols: ■▲ = data obtained for Glensol; ● = data
obtained for cold water; + = data for hot water experiments. Dashed lines show extended flooding with
Glensol.
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18. Evaluation of GEOR 1 for EOR
3.2 Further analysis
Analysis of fractional flow curves provides a means to predict how water flooding
could operate at a bigger scale and also helps to characterise processes and
mechanisms that are enhancing oil recovery during a GEOR 1 flood.
The simplest estimate of water flood efficiency is the mobility ratio, a parameter
that balances the viscous forces of one fluid phase against another; a mobility
ratio less than 1 characterises an efficient water flood regime and a ratio much
greater than 1 is an inefficient water flood. The mobility ratio estimated for the
cold-freshwater experiment is approximately 500 following water breakthrough.
Primary Recovery Extended water flood
100
Fresh water
Sea water
80
fractional water cut %
60
100
99
80
M>4
2.5
0.25
40
5
M=2
Wct %
60
M=
M=
40
20 20
0
0 0.2 0.4 0.6 0.8 1
Water saturation
0
0 0.2 0.4 0.6 0.8 1
Water saturation
Figure 3.5. Fractional flow behaviour of beadpack. ○● = data for primary and advanced stages of cold-
freshwater flood (solid blue line); ∆▲ = data for primary and advanced stages of cold-saltwater flood
(dashed blue line). Inset shows behaviour for idealised mobility ratios. Wct % = fractional water cut and M
= mobility ratio.
17

19. Evaluation of GEOR 1 for EOR
The fractional water-flow behaviour for the coldwater experiments are shown in
figure 3.5. After a small amount of heavy oil has been produced (water has
displaced oil from the beadpack thus increasing water saturation), water-cut
values are high. For comparative purposes fractional water-cut curves are also
shown for idealised systems with lower mobility ratios. Comparison of these
systems to the one used for experiments highlights the difficulty of producing
heavy oil: if a watercut of 80 % represented the operating limit for a given field,
then production of a heavy oil deposit with the characteristics of the micro-
beadpack would have to cease after production of less than 10 % of the movable
oil in place. For the lowest mobility ratio illustrated, with a low viscosity oil this
would be about 50 % of the oil in place.
100
80 oC 70 oC
85 oC
80
fractional water cut %
60 100
80
t
Oil we
40
et
60
Wct %
ter w
Wa
40
20 20
0
0 0.2 0.4 0.6 0.8 1
Water saturation
0
0 0.2 0.4 0.6 0.8 1
Water saturation
Figure 3.6. Fractional flow behaviour during thermal EOR, note wetability inversion at highest
temperature. Blue line from figure 3.5. Redlines = thermal EOR data.. × = data for hot water at 70 oC, + =
80 oC and ○ = data for 85o C.
18

20. Evaluation of GEOR 1 for EOR
Figure 3.6 presents the results for the thermal EOR experiments. An initial a drop
in oil viscosity for temperatures in the 70 to 80 oC range increases recovery
o
marginally, but at temperatures greater than 85 C a completely different
fractional flow behaviour results. The concave upwards graph is characteristic of
the fractional flow behaviour observed for low viscosity water-wet systems and
describes a situation where increased oil recovery is accompanied by relatively
minor increases in fractional water-cut.
100
80
Fresh water Glensol
fractional water cut %
60
Sea water Glensol
40
20
0
0 0.2 0.4 0.6 0.8 1
Water saturation
Figure 3.7. Fractional flow behavior under Glensol flood.▲∆ & ●○ = data for 1st and 2nd stages of EOR
with Glensol in freshwater. = 1st and 2nd stages of EOR with Glensol in saltwater.
From figure 3.7 it is clear that flooding with GEOR 1 improves the fractional flow
regime; arrival of the GEOR 1 flood-front at the end of the beadpack is marked by
a reduction in water-cut as an oil bank is mobilised and moved through the
beadpack. This effect is most pronounced for the saltwater experiment. However
19

21. Evaluation of GEOR 1 for EOR
late stage extended flooding with GEOR 1 in saltwater is characterised by an
increasing water-cut, but the shape and gradient of the line on figure 3.7 does
not suggest a change in wettability as was observed for the thermal method.
Although the extended floods using GEOR 1 in freshwater do not water-out
during the duration of the experiment, eventually this would occur.
Flooding with a low concentration of GEOR 1 may increase recovery via a range
of mechanisms:
1) An increase in heavy oil mobility caused by strong and rapid surfacting
action; GEOR 1 has been shown (by Glensol) to act rapidly on asphalt
associated with tar-sands and pipe-line precipitated asphaltenes where it
rapidly penetrates through oil residues to reach the oil-surface interface.
Results presented here suggest that the same effect occurs in a dynamic
environment. This gives GEOR 1 not only access to residual oil, but
access to heavy asphaltic oil in marginally tighter regions of the beadpack
that would be difficult to mobilise using water alone.
2) The formation of water in oil microemulsions with reduced oil viscosity.
Microemulsions have a much reduced viscosity and swell to form a
continuous mobile oil phase. This process is most evident for the saltwater
experiments and is expressed as a notable decrease in water-cut and an
increase in recovery.
3) If GEOR 1 viscosifies water it may also increase overall recovery by
stabilising the flood-front and being better able to mobilise oil. This would
aid sweep efficiency and increase overall recovery.
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22. Evaluation of GEOR 1 for EOR
3.3 Areal Sweep Efficiency
Unswept regions after coldwater flood
Unswept regions after coldwater flood
1 mm
Comparison after Glensol flood
Comparison after extended coldwater
Figure 3.8. Images showing increased areal sweep efficiency of Glensol flood at small scale. Top images
show beadpacks after primary waterflood. Bottom images show photographs of pack after 1st EOR stage.
Coloured overlays show outlines of unswept regions after primary flooding. After the coldwater flood areas
outlined in blue still contain black oil. After Glensol flood the areas outlined in blue are better swept.
Field-scale areal sweep efficiency is a function of geological heterogeneity and
cannot be assessed at the scale of the experiments reported here. However
regions of bypassed oil did develop during most experiments. This is evident in
most experiments after the initial waterflood stage (see Table 1.1 and 1.2).
GEOR 1-floods are notably effective at accessing oil within these regions. This
can be further illustrated by overlaying the outlines of regions of bypassed oil
(shown as blue lines) onto to the bead pack after the application of the EOR
method (figure 3.8). After an extended waterflood many dark patches of oil
remain within blue lines as cold water can not easily shift the heavy oil in these
regions. This is not the case after flooding with GEOR 1 where the areas
enclosed by blue lines, although large, contain few patches of dark oil. GEOR 1
has somehow managed to access regions initially inaccessible to the water
21

23. Evaluation of GEOR 1 for EOR
phase. A thermal method would be expected to mobilise heavy oil in such
regions by the conduction of heat, which does not depend on mass transfer to
lower viscosity. A chemical EOR method requires physical contact with the by-
passed or residual oil to mobilise it. The mobilisation of heavy oil in these regions
by GEOR 1 is therefore notable and attests to the rapid and deep surfacting
action of GEOR 1.
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24. Evaluation of GEOR 1 for EOR
4.0 Conclusion
The presence of very low concentrations of GEOR 1 in injected water
significantly enhances the recovery of heavy oil during waterflood. Heavy oil
production is brought forward relative to coldwater flooding with fresh and saline
water with high recoveries obtained more rapidly when flooding with GEOR 1
than with hotwater or coldwater benchmarks. The positive affect of GEOR 1 in
both fresh and saltwater highlights its robustness as an additive.
To the best of our knowledge GEOR 1 has unique properties as a chemical
additive as it is efficient and effective in salt- and freshwater when used at low
concentrations sets it apart from previous chemical methods of enhanced oil
recovery. GEOR 1 is cost effective and not designed to be recovered for
reinjection thus mitigating an important element of economic risk in EOR projects.
For example, where loss of surfactant by adsorption onto reservoir surfaces is
encountered during surfactant flooding this could feasibly be mitigated by
increasing the concentration of GEOR 1 in the injected water as the GEOR 1
itself is not an unreasonable cost increment or environmentally sensitive in an
EOR project. Because the GEOR 1 additive can be used in a variety of reservoir
formation water chemistries it should be possible to simplify programes of
additive treatment in field applications. This potentially reduces the costs and
risks typical of previous chemical methods of enhanced oil recovery which
required extensive design and compatibility studies.
The experimental results far exceeded our expectations for GEOR 1 and more
importantly demonstrated that the additive out-performs cold- and hot-water
floods in fresh- and salt-water. Our bead-pack experiments are a simplification of
natural reservoir conditions however, they provide an important insight into the
utility of GEOR 1, which encourages us to recommend designing an immediate
field trial.
23