SPE 142755
AS
Study of Seve
eral Environmentally Frie
endly Clay Stabilizers
S
I.A.. El-Monier, SPE,
S
and H.A. Nasr-El-Din, SPE, Texas
s A&M Universsity
Cop
pyright 2011, Society of Pe
etroleum Engin
neers
nference at M
METS held in
This paper was prepared for presentation at the SPE Projects and Facilities Challenges Con
ha, Qatar, 13–
–16 February 2011.
Doh
by
b an SPE pro
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ntained in an
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This paper was selected for presentation
ntents of the paper have not been re
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ermission to rreproduce in
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The abstract m
must contain
d to an abstra
illustrattions may nott be copied. T
prin
nspicuous ack
knowledgmentt of SPE copyyright.
con
stract
Abs
Quaaternary aminee-based chemicals have been
n used for maany years as cclay stabilizers. An Al/Zr-baased clay stabiilizer, A, was
devveloped. It show
wed great effeectiveness in mitigating
m
fines migration annd overcame thhe leaching efffect of HCl. In this study,
Stabbilizer A was examined and its performan
nce was compaared with two ccommercial cllay ones: tetram
methyl ammonnium chloride
andd choline chloriide.
T
The type of co
ores (6 in. leng
gth and 1.5 in. diameter) thatt were used is Berea sandstonne of 60-85 m
md; mainly conntained 5 wt%
kaoolinite. Variouss coreflood exp
periments werre performed to
o assess the e ffectiveness off each of the tthree stabilizerrs at 200 and
3000oF. Inductively
y Coupled Plassma was used to
t analyze the core
c
effluent too measure the cconcentrations of key cationss.
During tetram
methyl ammoniium chloride and
a choline chlloride coreflooods, significannt amount of fiines were noteed in the core
was noted durinng mixing of
effluent samples, which means that these staabilizers were not effective. A bad odor oof ammonia w
w HCl acid. Choline chlorride was effective at high conncentrations. S
Stabilizer A showed good behhavior during
chooline chloride with
coreeflood experim
ments, and prov
ved to be betterr than the two commercial
c
staabilizers at low
w concentrationns. Stabilizer A worked very
welll, and no bad smell
s
or fines were
w produced
d. In addition, Stabilizer
S
A is an inorganic-bbased fluid, ennvironmentallyy friendly, and
doees not have an
ny smell; in co
ontrast to quaternary amine chemicals. Unnlike previous Al-based stabbilizers (hydroxy aluminum
soluutions), the new
w stabilizer waas not removed
d by HCl and no
o decline in peermeability wass noted followiing HCl injectiion.
Intrroduction
Most of the amin
ne-based clay stabilizers
s
worrk on the princciple of substiitution of catioonic species foor a sodium ioon in the clay
nic species is generally
g
selectted such that itts hydrated vollume is less thaan that of the ssodium ion, ressulting in less
lattiice. The cation
sweelling when thee clay is exposed to aqueous fluids. Of the cationic speciees used, organiic quaternized amines (Himees and Vinson
19889; Patel at all. 1999) and potassium chlloride are favored. Potassiuum chloride hhas fallen out of favor duee to the high
conncentration, typ
pically greater than 3 wt% required for stab
bilization, resul
ulting in a highh level of unwaanted chloride concentration
(Pattel 2009). Thee two most co
ommon materiials currently in use are (2--hydroxyethyl)) trimethyl am
mmonium chlooride (choline
chlooride) and tetraamethyl ammonium chloride (TMAC).
C
Choline chloride is an ammo
onium salt com
mpound, (2-hyd
droxyethyl) triimethyl ammonnium chloride.. It is readily bbiodegradable
accoording to OEC
CD-criteria. In atmosphere, ch
holine chloridee will rapidly ddegrade accordding to a half life time of abbout 6.9 hours
(Braaun 2004). Th
he main advanttage of monocaationic aminess is the reducedd level of treaatment, typicallly 1 to 3 % ass compared to
2
[SPE 142755]
inorganic salts. Most of them have limited application due to temperature stability, strong odors, toxicity or lower level of
inhibition. Table 1 summarizes the chemistry, functionality, and some shortcomings of choline chloride (Patel 2009). Patel et al.
(2007) showed that the main disadvantage of choline chloride is the low level of inhibition and solid tolerance.
Tetramethyl ammonium chloride (TMAC) is a quaternary ammonium salt with the chemical formula [(CH3)4N]Cl. It is used as
a KCl substitute temporary clay stabilizer. TMAC's main advantage over potassium chloride is the treatment rates that can be
accomplished, typically the product is recommended at 3 wt%. Theoretically, TMAC is the most efficient quaternized amine. The
main drawback of TMAC is its odor (Himes and Vinson 1989). However, the chemistry, functionality, and some shortcomings of
TMAC are given in Tables 1 and 2, which indicate that TMAC fails in the toxicity tests (Patel 2009). Poelker (2008) introduced
new chemicals denoted A4819 and A4840, He compared them with the conventional TMAC and claimed that the three stabilizers
had acceptable level of mitigation, however the permeability his results showed that there was a reduction in permeability during
the tap water injection. Smith et al. (2006) showed that TMAC provided temporary protection because the small cations, which
were used to replace the sodium cations, are themselves quickly replaced, once flow from well is re-established.
Sharma and Sharma (1994) mentioned that polymers containing quaternary ammonium salts, hydrolysable metal ions such as
zirconium oxychloride, and hydroxyl aluminum have three potential disadvantages: 1) charge neutralization does not prevent
mechanical particle dislodgment at high flow rates, 2) they provide temporary treatment since polyvalent ions tend to desorb over
times, and 3) some chemicals used are relatively expensive. They developed a new technique, Surface Adsorption Polymerization
(SAP) process, for fines stabilization using polymerizable ultra-thin films.
Thomas et al. (1976) showed the effect of chemical treatment on clay migration problem using SEM techniques. They claimed
that unlike hydroxyl aluminum solution, zirconium is not removed by acid and can be applied effectively in acid. On the contrary,
Himes et al (1991) showed that the treatments by hydroxyl aluminum and zirconium oxychloride need to retreat after acidizing and
have restriction to non carbonate containing sandstone formations (Coppell et al, 1973). They also presented a new clay treatment
for low permeability sandstones.
His (1984) presented an evaluation of clay control additives for matrix acidizing operations. He proved experimentally that
zirconium oxychloride overall performance slightly better than other organic polymer typed additives. However, some rapid
permeability loss following acid treatments was observed for cores treated by zirconium oxychloride. Haskin (1976) reviewed
hydroxy aluminum treatments. From field experience, a precipitation may form if hydroxyl aluminum contacts large negatively
charged organic anions. This may cause formation damage.
El-Monier and Nasr-El-Din (2010) presented Stabilizer A, Al/Zr-based clay stabilizer, which is part of a new generation of
metal polymers for use in various oilfield applications. It is 100% inorganic and displays very low toxicity as compared to
commonly used clay stabilizers such as quaternary amine compounds. Table 3 gives the toxicological and chronic/reproductive
data for stabilizer A. Coreflood studies were conducted on this chemical. It was proved that Stabilizer A is effective as a clay
stabilizer, and it can work up to 300oF. HCl did not dissolve much of it, unlike the previous Al-based and Zr-based clay stabilizers
such as hydroxyl aluminum and zirconium oxychloride solutions.
Previous studies claimed that TMAC and choline chloride are environmentally friendly and are effective in inhibiting clay
swelling in a down-hole formation for well stimulation and stabilizing clay-containing formation (Afton 1994; Shimizu 1998).
Peolker et al. (2008) claimed that the effectiveness of the conventional TMAC, despite the reduction in permeability that was
noticed following the stabilizer injection. Environmental issues were introduced in the previous sections, and it is obvious that
there is a great confusion about these two chemicals. On the other hand, the effectiveness of these chemicals was not clear as clay
stabilizers.
In general, a clay stabilizer should provide equal or superior return of permeability in core flow studies as compared with
effective solutions. Core flow studies were not presented in the literature for these two chemicals. Therefore, core flood studies
were conducted on Berea sandstone cores to investigate the effectiveness of tetramethyl ammonium chloride and choline chloride.
The performance of Stabilizer A was compared with these two commercial clay stabilizers up to 300oF. Inductively Coupled
Plasma (ICP) was used to analyze the core effluent to measure the concentrations of key cations.
Materials
Clay stabilizer, Stabilizer A, was obtained as an aqueous solution, and its physical properties are given in Table 4. 5 wt% NaCl
solutions were filtered through 1 µm filter paper. 15 wt% HCl was used in addition to 0.3 vol% corrosion inhibitor (CI). Type of
cores was Berea sandstone (1.5 in. diameter, and 6.0 in. length); Table 5 gives the mineralogy of Berea sandstone as was
determined using XRD technique. Each solution was prepared by mixing for 30 minutes with a magnetic stirrer. All clay stabilizer
solutions were prepared in 5 wt% NaCl.
A schematic diagram of the core flood setup is shown in Fig. 1. It included a core holder and three transfer vertical vessels that
were connected in parallel to the core holder; the first vessel can be loaded with a maximum of 2 liter of the brine, the second can
be loaded with a maximum of 2 liter of the DI water, and the third can be loaded with a maximum of 1 liter of the stabilizer or the
HCl solution. Properties of the prepared solutions were measured and are given in Table 6. Injection rate was kept constant at 5
[SPE 142755]
3
cm3/min. This rate was selected because it did not cause mechanical fines migration. Berea sandstone cores were dried and
saturated with 5 wt% NaCl overnight for pore volume (PV) calculations. A new core was used in each experiment. A confining
pressure of 1,500 psi was applied and the back pressure was 1,000 psi. Samples of the core effluent were collected during all
experiments.
Instruments
To evaluate the properties of Stabilizer A, tetramethyl ammonium chloride, choline chloride and their solutions, various apparatus
were used. Orion 370 PerpHecT Ross Electrode was used to measure the pH. Thermo Scientific Orion 950 ROSS FAST QC™
Titrator was used to measure the concentration of HCl in the core effluent. The density was measured using DMA 35N portable
density meter. Capillary viscometer (Cannon Ubbelohde viscometer, size 1) was used to determine the viscosity of Stabilizer A
and acid solutions. Inductively Coupled Plasma (WinLab32 ICP software) was used to determine the concentrations of key cations
in the core effluent samples.
Results and Discussion
Effectiveness of Clay Stabilizers at 2 wt% Concentration
The general procedure for the coreflood experiments was as follows: injection of 5 wt% NaCl to measure the initial core
permeability, then 2 PV of the stabilizer solution. At the end, DI water was injected. El-Monier and Nasr-El-Din (2010) optimized
the concentration of Stabilizer A and showed the great effect of 2 wt% Stabilizer A on mitigating fines migration as shown in Fig.
2, where no increase in the pressure drop across the core was noted during the DI water injection up to 300oF. They also tested the
effect of 15 wt% HCl on the performance of this stabilizer, and it worked very well, and the leaching effect was not significant.
Core effluent samples were collected and showed no Al and Zr through the analysis of the Inductively Coupled Plasma (ICP).
They proved that Stabilizer A was effective due to the presence of trivalent cation Al+3 and tetravalent cation Zr+4, which reduced
Debye’s length, increased the electrostatic attraction force in the electric double layer between ions, and shielded the negative
charge of clays (Masliyah and Bhattacharjee 2006). In aqueous solutions, Zr salts hydrolyze to form polynuclear ions that perform
as ions of much higher charges. Because of the high positive charge, the zirconium polynuclear ion is probably several million
times stronger as a clay stabilizer than the conventional calcium and potassium salts (Veley 1969). Therefore, injecting low
salinity fluids after the stabilizer solution will not induce fines migration, and will not affect the electrical charge of naturally
occurring clay platelets in the formation.
Coreflood experiments of 2 wt% TMAC were investigated at 200 and 300oF, it followed the same procedure as that used with
Stabilizer A, at 200oF, Fig. 3 shows that there was an increase in the pressure drop across the core during fresh water injection.
Fines in the core effluent samples were also noted, which indicate fines migration problems. TMAC induced fines migration and
was not effective. This might be because TMAC used as a KCl substitute temporary clay stabilizer, which means that they are
themselves quickly replaced once flow from the well is re-established. Similar results were obtained at 300oF. These results
indicate that this stabilizer is not effective at 2 wt% and temperatures of 200 and 300oF/
At 200oF as shown in Fig. 4, there was an increase in the pressure drop across the core during the DI water injection and fines
were noticed in the core effluent samples. This means that the permeability of the core declined. This is because choline chloride is
a monocationic clay stabilizer, which acts as a temporary clay stabilizer and can be easily removed once the flow of DI water is
resumed, and it has low level of inhibition. It was also noticed that soaking the core for one hour and resuming the flow made the
pressure drop to increase, which indicates that more damage can be created after shutting the experiment for a short period.
Although the claims of previous work for its effectiveness, 2 wt% choline chloride was not effective and induced fines migration
problems.
Effectiveness of Clay Stabilizers at 4 wt% Concentration
2 wt% of choline chloride and TMAC did not show good potential for mitigating fines problems. These chemicals were tested
again at higher concentration of 4 wt% at 200oF to make sure from their ability to stabilize the fines in the core. The same
procedure was followed, and the results were obtained as shown in Figs. 5 and 6 for 4 wt% TMAC and 4 wt% choline chloride,
respectively. It can be concluded that TMAC still introduces damage to the formation, where fines were noted in the core effluent
and the pressure drop across the core was increased. In case of 4 wt% choline chloride, fines problems were mitigated and no
increase in the pressure was created. This means that 4 wt% choline chloride was effective and enough to prevent fines migration.
Effect of HCl Acid
More tests were conducted to investigate the effect of HCl on the stabilizers under study. After treating the cores with 2 wt% of the
clay stabilizers at 200 and 300oF, the stabilizer was left for 1 hour for soaking inside the core holder for each experiment
separately, then injection of DI water was resumed to make sure that the stabilizer was still working and to obtain stabilization in
the pressure drop. 15 wt% HCl plus 0.3 vol% CI was injected after DI water injection and followed again by DI water injection to
4
[SPE 142755]
examine the leaching effect of HCl on the three clay stabilizers at 200 and 300oF. Figs. 7 through 11 showed the results of these
experiments. During the injection of HCl with the cores that were treated by the stabilizers, the same fluctuation in the pressure
drop across the cores was noticed. After HCl injection, the pressure drop decreased due to the injection of DI water, and the
permeability enhanced as given in Table 7. Hence, Stabilizer A was still effective even after HCl injection as the pressure drop did
not increase due to the enhancement that was introduced by HCl by the dissolution of minerals. Samples were collected and core
effluent analysis will be presented later. An enhancement was noticed also in the cases of choline chloride and TMAC due to HCl
stimulation.
The increase in pressure during HCl injection was due to the release of CO2. Berea cores contain carbonate minerals, which
were dissolved by HCl, and released CO2. Solubility of CO2 decreased as the concentration of CaCl2 increased in water. That
increase in the pressure drop diminished during the injection of DI water.
Analysis of Core Effluent
Samples of the core effluent were collected during each experiment, and Al, Zr, Fe, Ca, and Mg were analyzed. Inductively
Coupled Plasma (ICP) was used to measure the concentrations of the different cations. During Stabilizer A, TMAC, and choline
chloride injection, the concentrations of Al, Zr, total Fe, Ca, and Mg were zero in the core effluent. This indicates that during the
stabilizer injection up to 300oF, Stabilizer A worked very well and attached to the grain surfaces where no Al or Zr was observed
in the core effluent samples during its injection. No Al or Zr was present originally in TMAC and choline chloride clay stabilizers,
and no Al was leached from the core. Figs. 12 through 19 show the elemental analysis of these coreflood experiments during HCl
injection at 200oF. It can be shown that during the corefloods at 200oF, Al was noticed in the core effluent samples during HCl
injection. This means that HCl leached a considerable amount of Al, which could be due to the Al contained in the stabilizer itself,
or the Al minerals in clays and feldspars. During the HCl injection period in TMAC and choline chloride, a considerable amount
of Al was leached by HCl, and this is because of the Al minerals in clays and feldspars. Al had higher values in case of Stabilizer
A during HCl injection because of the Al contained originally in the stabilizer. High amounts of total Fe, Ca, and Mg were noticed
during HCl injection in the three cases of clay stabilizers because of the dissolution effect of iron containing minerals, and
carbonate minerals from calcite and dolomite. No Zr was noticed up to 300oF in the core effluent samples. At high concentration, 4
wt% of TMAC and choline chloride, it can be seen that the amount of Al cations was much less than the concentration at 2 wt%.
Applying material balance on the Al coming out in the core effluent, the following results were obtained and presented in Table
8: at 200oF, the amount of Al in the core effluent of 2 wt% Stabilizer A experiment was due to the Al contained in the stabilizer
itself and in the core minerals, and it equals 130 mg. The amount of Al in the core effluent of the 2 wt% TMAC experiment equals
64 mg, which was due to the Al in the core minerals only. This means that the Al remained in the core due to stabilizer A itself
was 56 wt%. At 300oF, the amount of Al remained inside the core due to Stabilizer A was 78 wt%. This confirms that HCl could
not remove much of the Al contained in Stabilizer A. Besides, no Zr was noticed in the core effluent, which confirms that no Zr
was leached by HCl.
The amount of Al in the core effluent of the 2 wt% choline chloride experiment equals 10.8 mg, which was due to the Al in the
core minerals only. This means that the Al remained in the core due to stabilizer A itself based on the choline chloride experiment
at 200oF was 20 wt%. Again, no Zr was noticed in the core effluent. It was also noticed that the concentrations of the different
cations that were leached by HCl in case of choline chloride is much less than the other two clay stabilizers, but still higher
concentration of choline chloride is required to stabilizer the clays in the cores.
Conclusions
Three environmentally friendly clay stabilizers were examined in the present study. The effect of 15 wt% acid on the treated cores
was also studied. Based on the results obtained, the following conclusions can be drawn:
1. Stabilizer A worked very well up to 300oF and no fines were observed in the core effluent.
2. TMAC was not effective where fines were induced after injecting DI water.
3. Choline chloride was not effective at 2 wt%, however it worked very well at higher concentrations.
4. Zr was not leached by HCl after Stabilizer A injection.
5. HCl leached Al from the treated cores however, no decline in permeability was noted.
Nomenclature
LC50 (50% lethal concentration)
=
LD50
=
NOEC (no observed effect
concentration)
=
The concentration of a chemical in air or of a chemical in water
which causes the death of 50% of a group of test animals
The amount of a chemical, given all at once, which causes the death
of 50% of a group of test animals.
The test concentration immediately below the lowest tested
concentration with statistically significant adverse effect.
[SPE 142755]
5
IC25
=
Chronic LOEC (Lowest Observed
Effect Concentration)
Chronic MATC (maximum
acceptable toxicant
concentrations)
=
=
IC stands for inhibition concentration. The IC25 is also a calculated
percentage of effluent. It is the level at which the organisms exhibit
25 percent reduction in a biological measurement such as
reproduction or growth. It is calculated statistically and used in
chronic toxicity testing.
The upper end of MATC range is represented by the lowest test
concentration that has statistically significant effect.
The MATC is an estimated toxic threshold concentration falling
between the highest concentration showing no effect and the next
highest concentration showing a toxic effect when compared to the
controls
References
Afton, C.W. and Gabel, R.K. 1994. Clay Stabilizers. US Patent No. 5,342,530.
Braun, C. 2004. Experimental SIDS Initial Assessment Report for SIAM 19. Berlin, Germany, 19-22 October. UNEP Publication.
El-Monier, I.A., and Nasr-El-Din, H.A. 2010. A New Environmentally Friendly Clay Stabilizer. Paper SPE 136061 presented at
the SPE Production and Operations Conference and Exhibition held in Tunis, Tunisia, 8–10 June.
Haskin, C.A. 1976. A Review of Hydroxy-Aluminum Treatments. Paper SPE 5692 presented at the SPE International of AIME
Symposium on Formation Damage Control held in Houston, Texas, 29-30 January.
Himes, R.E. and Vinson, E.F. 1989. Fluid additives and Method for Treatment of Subterranean Formations. U.S. Patent No.
4,842,073.
Himes, R.E., Vinson, E.F., and Simon, D.E. 1991. Clay Stabilization in Low-Permeability Formations. SPE Prod Eng, 6 (3): 252258.
His, C.D. 1984. Evaluation of Clay Control Additives for Matrix Acidizing. Paper SPE 13086 presented at the SPE Annual
Technical Conference and Exhibition held in Houston, Texas, 16-19 September.
Masliyah, J.H, and Bhattacharjee, S. 2006. Electrokinetic and Colloid Transport Phenomena. New Jersey. A John Wiley & Sons,
Inc.
Patel, A.D. 2009. Design and Development of Quaternary Amine Compounds: Shale Inhibition with Improved Environmental
Profile. Paper SPE 121737 presented at the SPE International Symposium on Oilfield Chemistry held in The Woodlands,
Texas, 20-22 April.
Patel, A.D., Stamatakis, E., Young, S, and Friedheim, J. 2007. Advances in inhibitive Water-Based Drilling Fluids-Can They
Replace Oil-Based Muds? Paper SPE 106476 presented at the SPE International Symposium on Oilfield Chemistry held in
Houston, Texas, 28 February-2 March.
Patel, A., Thaemlitz, C.J., McLaurine, H.C. and Stamatakis, E. 1999. Drilling Fluid Additives and Method for Inhibiting
Hydration. U.S. Patent No. 5,908,814.
Poelker, D.J. 2008. Drilling Polyamine Salts As Clay Stabilizing Agents. U.S. Patent No. 2008/0108523 A1.
Shimizu, S. 1998. Method of manufacturing tetramethyl ammonium hydroxide. US Patent No. 4572769.
Sharma, B.G., and Sharma, M.M. 1994. Polymerizable Ultra-Thin Films: A New Technique for Fines Stabilization. Paper SPE
27345 presented at the SPE International Symposium on Formation Damage Control held in Lafayette, Louisiana, 7-10
February.
Smith, C., Oswald, D., and Daffin, M.D. 2006. Clay Control Additive for Wellbore Fluids. US Patent No. 2006/0289164 A1.
Thomas,R.L., Crowe, C.W., and Simpson, B.E. 1976. Effect of Chemical Treatment upon Formation Clays is Revealed by
improved SEM Techniques. Paper SPE 6007 presented at the SPE Annual Fall Technical Conference and Exhibition held in
New Orleans, Louisiana, 3-6 October.
Veley, C.D., 1969. How Hydrolyzable Metal Ions React with Clays to Control Formation Water Sensitivity. JPT, 21 (9): 11111118.
6
[SPE 142755]
Ta
able 1─Monoccationic Amin e Shale Stabillizers (Patel 20009)
Structture/Compositiion
Function/Limitation
HS&E/Toxxicity
pH and Tem
mperature
Marine toxiicity,
Limitattions
bad odoor
Name
N
(T
TMAC)
Cholin
ne Chloride
C
Compatibility w
with additives
lim
mitation in shaale inhibition,
ammoniaa odor
Material
TMA
AC
Choline Ch
hloride
Material
TMA
AC
Biodegradaable,
non-toxicc to
marinee
Table 2─To
oxicity of Catiionic Amines ( Patel 2009)
Co
oncentration
L
LC50
7 lb
b/bbl in GM#7
<110,000
>500,0000 ppm SPP
Conccentration
Microotox
2%
0.900%
Table 3─
─ Toxicological Data of Sta
abilizer A (El-M
Monier and N
Nasr-El-Din 20010)
Acute
A
Data
Rat LD50, mg/kg
m
Fathead min
nnow 96-hour LC
L 50, mg/l
Fathead min
nnow acute NO
OEC, mg/l
3775
825
603
Chronic/R
Reproductive D
Data
Ceriodaphniia dubia Chron
nic NOEC, mg//l
Ceriodaphniia dubia Chron
nic MATC, mg/l
Ceriodaphniia dubia Chron
nic LOEC, mg//l
Ceriodaphniia dubia Chron
nic IC25, mg/l
3.8
5.3
7.5
5.1
Table 4─Properties
4
of the Stabilizzers as Receivved
Stabilizer A
Density at 77oF, g/cm3
1.4494
pH
2..9
Viscosity at 77oF, cP
96
125,,560
Al Concentrration, ppm
Zr Concentration, ppm
38,2270
bilizer TMAC
Stab
Density at 77oF, g/cm3
pH
Viscosity at 77oF, cP
Stabilizerr Choline Chlooride
Density at 77oF, g/cm3
pH
Viscosity at 77oF, cP
1.0018
8..9
16
1.009
7..5
19
Resultss
Fail
Pass
Resultss
Fail
[SPE 142755]
7
Table 5─Minarology of Berea Sandstone
Mineral
Concentration, wt%
Quartz
86
Kaolinite
5
Feldspar
3
Chlorite
2
Calcite
2
Dolomite
1
Illite
1
Table 6─Properties of the Solutions Used in the Core flood Experiments
Brine 5 wt% NaCl:
density at 77oF, g/cm3
1.033
viscosity at 77oF, cP
1.05
pH
7.7
DI water:
density at 77oF, g/cm3
0.998
viscosity at 77oF, cP
0.95
pH
7.0
2 wt% Stabilizer A prepared in 5 wt% NaCl:
density at 77oF, g/cm3
1.049
viscosity at 77oF, cP
1.08
pH
4.2
2 wt% Stabilizer TMAC prepared in 5 wt% NaCl:
density at 77oF, g/cm3
1.032
viscosity at 77oF, cP
1.063
pH
7.3
2 wt% Stabilizer choline chloride prepared in 5 wt% NaCl:
density at 77oF, g/cm3
1.034
viscosity at 77oF, cP
1.055
pH
8.0
4 wt% Stabilizer choline chloride prepared in 5 wt% NaCl:
density at 77oF, g/cm3
1.035
viscosity at 77oF, cP
1.05
pH
7.2
4 wt% Stabilizer TMAC prepared in 5 wt% NaCl:
density at 77oF, g/cm3
1.032
viscosity at 77oF, cP
1.03
pH
7.5
15 wt% HCl:
density at 77oF, g/cm3
1.075
viscosity at 77oF, cP
1.9
pH
0
Table 7─Permeability at the End of the Coreflood Experiments at 200oF
Coreflood Experiments
Initial Core
Final Core
Permeability, md
Permeability, md
2 wt% Stabilizer A test
66.7
75.9
2 wt% Stabilizer TMAC test
86
84.4
4 wt% Stabilizer TMAC test
64
62
2 wt% Stabilizer choline chloride test
81.5.4
117
4 wt% Stabilizer choline chloride test
65
96
8
[SPE 142755]
Table 8─Al amount remained in the core after the experiments
Coreflood Experiment
Al Remained, %
56
Stabilizer A at 200oF based on TMAC
20
Stabilizer A at 200oF based on choline chloride
[SPE
E 142755]
9
Fig. 1─C
Coreflood Settup.
Pressure Drop Across the Core, psi
10
00
2 wt%
% Stabilizer A
in 5 wt% NaC
Cl
8
80
6
60
5 wt%
% NaCl
DI water
4
40
2
20
0
0
5
10
15
Cumu
ulative Injec
cted Volum
me, PV
Fig. 2─Pressure drop across th
he core of 2 wtt% Stabilizer A at 200oF ass a function off the cumulativve injected voolume at a flow
w rate =
3
5 cm
m /min.
10
[SPE 142755]
Pressure Drop Across the Core, psi
100
2 wt%
% Stabilzer TMAC
T
in
n 5 wt% NaC
Cl
80
DI water
5 wt%
% NaCl
60
40
20
0
0
2
4
6
8
10
Cumulative Inje
ected Volum
me, PV
Fig. 3─Pressure drop across th
he core of 2 wtt% TMAC at 200oF as a fun
nction of the ccumulative injjected volumee at a flow
3
ratee = 5 cm /min. Fines were noticed
n
in the samples
s
after 0.5 PV of watter injection.
150
Pressure Drop, psi
120
Soaking for 1 hr
2 wt% Choli
2 wt% Stabiine Chloride
lzer TMAC
in 5 wt%
% NaCl
% NaCl
in 5 wt%
90
60
5 wt%
w
NaCl
DI water
w
30
0
0
5
10
15
20
Cumulative Injected Volume,
V
PV
he core of 2 wtt% choline ch
hloride at 200o F as a functioon of the cumu
ulative injected volume at
Fig. 4─Pressure drop across th
3
a flow rate = 5 cm
m /min. Fines were noted in
n the core efflu
uent samples aafter 0.5 PV of water injectiion.
[SPE
E 142755]
11
250
Pressure
essu e Drop,
op, ps
psi
200
4 wt% TMAC
C prepared
in 5 wt%
% NaCl
150
DI water
5 wt% NaC
Cl
100
50
0
0
3
6
9
1
12
15
Cumulativ
ve Injected Volume,
V
PV
Fig. 5─Pressure drop across th
he core of 4 wtt% TMAC at 200oF as a fun
nction of the ccumulative injjected volumee at a flow
3
ratee = 5 cm /min. Fines were noticed
n
in the samples
s
after 1 PV of waterr injection.
150
Pressure Drop, psi
120
4 wt% Ch
holine Chloriide
prepared in 5 wt% Na
aCl
90
60
5 wt% NaC
Cl
DI water
w
30
0
0
3
6
9
12
Cumulative Injected Volume,
V
PV
Fig. 6─Pressure drop across th
he core of 4 wtt% choline ch
hloride at 200o F as a functioon of the cumu
ulative injected volume at
3
a flow rate = 5 cm
m /min.
12
[SPE 142755]
Pressure Drop Across the Core, psi
100
15 wt% HCl
80
60
DI water
40
DI water
20
0
14
18
22
26
Cumulative Injected Volume, PV
Fig. 7─Pressure drop across the core during 15 wt% HCl injection at 200oF as a function of the cumulative injected volume
at a flow rate = 5 cm3/min after 2 wt% Stabilizer A treatment.
Pressure Drop Across the Core, psi
100
15 wt%
HCl
80
60
DI water
DI water
40
20
0
14
18
22
26
Cumulative Injected Volume, PV
Fig. 8─Pressure drop across the core during 15 wt% HCl injection at 200oF as a function of the cumulative injected volume
at a flow rate = 5 cm3/min after 2 wt% TMAC treatment.
[SPE 142755]
13
400
15 wt%
HCl
350
Pressure Drop, psi
300
250
200
DI water
DI
water
150
100
50
0
15
20
25
30
Cumulative Injected Volume, PV
Fig. 9─Pressure drop across the core during 15 wt% HCl injection at 200oF as a function of the cumulative injected volume
at a flow rate = 5 cm3/min after 4 wt% TMAC treatment.
150
15 wt%
HCl
Pressure Drop, psi
120
90
DI
water
DI water
60
30
0
20
25
30
35
Cumulative Injected Volume, PV
Fig. 10─Pressure drop across the core during 15 wt% HCl injection at 200oF as a function of the cumulative injected
volume at a flow rate = 5 cm3/min after 2 wt% choline chloride treatment.
40
14
[SPE 142755]
150
Pressure Drop, psi
120
15 wt%
HCl
90
60
DI
water
DI water
30
0
12
15
18
21
24
27
30
Cumulative Injected Volume, PV
Fig. 11─Pressure drop across the core during 15 wt% HCl injection at 200oF as a function of the cumulative injected
volume at a flow rate = 5 cm3/min after 4 wt% choline chloride treatment.
6000
TMAC in
5et%
NaClNaCl
at 200F
TMAC
5 wt%
Stabilizer
in 5wt%
5 wt%NaCl
NaCl
Stabilizer A in
200F----choline
5 wt% NaCl
choline chlordie
chloride atin200F
Al Concentration, ppm
5000
15 wt% HCl
4000
3000
DI
water
2000
DI water
1000
0
20
21
22
23
24
25
Cumulative Injected Volume, PV
Fig. 12─Al concentration in the effluent of 2 wt% Stabilizer A, TMAC and choline chloride at 200oF corefloods during HCl
injection.
[SPE 142755]
15
60000
Stabilizer
DI water at room T
TMAC
in 5tmac
wt%inNaCl
Stabilizer A
at NaCl
T=200F
Stabilizer
A in
inbrine
5 wt%
Choline
5 wt%inNaCl
Stabilizerchloride
choline in
chloride
brine at T=300F
Total Fe Concentration, ppm
50000
15 wt%
HCl
40000
30000
20000
DI
water
DI water
10000
0
20
21
22
23
24
25
Cumulative Injected Volume, PV
Fig. 13─Total Fe concentration in the effluent of 2 wt% Stabilizer A, TMAC and choline chloride at 200oF corefloods during HCl
injection.
60000
Stabilizer
in DI
water at room ------T
TMAC intmac
5 wt%
NaCl
Stabilizer
at T=200F
StabilizerAAininbrine
5 wt%
NaCl
choline chloride
in 5 wt%in NaCl
Stabilizer
choline chloride
brine at T=300F
Ca Concentration, ppm
50000
15 wt%
HCl
40000
30000
DI
water
DI water
20000
10000
0
20
22
24
26
Cumulative Injected Volume, PV
Fig. 14─Ca concentration in the effluent of 2 wt% Stabilizer A, TMAC and choline chloride at 200oF corefloods during
HCl injection.
16
[SPE 142755]
12000
Stabilizer
in DI
water at room T-------TMAC intmac
5 wt%
NaCl
Stabilizer
at T=200F
StabilizerAAininbrine
5 wt%
NaCl
Choline chloride
in 5 wt%
NaCl at T=300F
Stabilizer
choline chloride
in brine
Mg Concentration, ppm
9000
15 wt%
HCl
DI water
DI water
6000
3000
0
20
22
24
Cumulative Injected Volume, PV
Fig. 15─Mg concentration in the effluent of 2 wt% Stabilizer A, TMAC and choline chloride at 200oF corefloods during
HCl injection.
1000
TMAC
a--------------t 200F
TMAC5et%
in 5 NaCl
wt% NaCl
Al Concentration, ppm
cholinechloride
chlordie
in 5 wt% NaCl
choline
at 200F
800
15 wt% HCl
600
400
DI
water
DI water
200
0
20
21
22
23
24
25
Cumulative Injected Volume, PV
Fig. 16─Al concentration in the effluent of 4 wt% TMAC and choline chloride at 200oF corefloods during HCl injection.
[SPE 142755]
17
60000
Stabilizer
in DI
water at room T
TMAC intmac
5 wt%
NaCl
Choline chloride
in 5 wt%
NaClat T=300F
Stabilizer
choline chloride
in brine
Total Fe Concentration, ppm
50000
15 wt%
HCl
40000
30000
DI
water
20000
DI water
10000
0
20
21
22
23
24
25
Cumulative Injected Volume, PV
Fig. 17─Total Fe concentration in the effluent of 4 wt% TMAC and choline chloride at 200oF corefloods during HCl
injection.
60000
Stabilizer
tmac
DI water at room ------T
TMAC
in 5
wt%inNaCl
choline
chloride
5 wt%inNaCl
Stabilizer
choline in
chloride
brine at T=300F
Ca Concentration, ppm
50000
40000
30000
DI water
15 wt%
HCl
DI water
20000
10000
0
20
22
24
Cumulative Injected Volume, PV
Fig. 18─Ca concentration in the effluent of 4 wt% TMAC and choline chloride at 200oF corefloods during HCl injection.
18
[SPE 142755]
12000
oF T-------Stabilizer
in DI
water
at room
TMAC in tmac
5 wt%
NaCl
at 200
o
Choline chloride
in 5 wt%
atT=300F
200 F
Stabilizer
choline chloride
in NaCl
brine at
Mg Concentration, ppm
9000
DI water
15 wt%
HCl
DI water
6000
3000
0
20
22
24
Cumulative Injected Volume, PV
Fig. 19─Mg concentration in the effluent of 4 wt% TMAC and choline chloride at 200oF corefloods during HCl injection.