U.S. patent application number 13/555452 was filed with the patent office on 2013-01-24 for low interfacial tension surfactants for petroleum applications.
This patent application is currently assigned to Soane Energy, LLC.. The applicant listed for this patent is Michael C. Berg, John H. Dise, Kevin T. Petersen, David Soane, Kristoffer K. Stokes, Atul C. Thakrar. Invention is credited to Michael C. Berg, John H. Dise, Kevin T. Petersen, David Soane, Kristoffer K. Stokes, Atul C. Thakrar.
Application Number | 20130023457 13/555452 |
Document ID | / |
Family ID | 41400858 |
Filed Date | 2013-01-24 |
United States Patent
Application |
20130023457 |
Kind Code |
A1 |
Stokes; Kristoffer K. ; et
al. |
January 24, 2013 |
LOW INTERFACIAL TENSION SURFACTANTS FOR PETROLEUM APPLICATIONS
Abstract
The invention relates to a class of novel surfactants that have
utility in the recovery and/or extraction of oil.
Inventors: |
Stokes; Kristoffer K.;
(Jamaica Plain, MA) ; Berg; Michael C.;
(Somerville, MA) ; Soane; David; (Chestnut Hill,
MA) ; Petersen; Kevin T.; (Cheshire, CT) ;
Dise; John H.; (Kirkland, WA) ; Thakrar; Atul C.;
(Minneapolis, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Stokes; Kristoffer K.
Berg; Michael C.
Soane; David
Petersen; Kevin T.
Dise; John H.
Thakrar; Atul C. |
Jamaica Plain
Somerville
Chestnut Hill
Cheshire
Kirkland
Minneapolis |
MA
MA
MA
CT
WA
MN |
US
US
US
US
US
US |
|
|
Assignee: |
Soane Energy, LLC.
|
Family ID: |
41400858 |
Appl. No.: |
13/555452 |
Filed: |
July 23, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12481072 |
Jun 9, 2009 |
8227383 |
|
|
13555452 |
|
|
|
|
61060004 |
Jun 9, 2008 |
|
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|
Current U.S.
Class: |
510/188 ;
208/332; 208/334; 208/390; 554/121; 568/608 |
Current CPC
Class: |
C09K 8/584 20130101;
C10G 2300/80 20130101; C07C 69/34 20130101; C11D 1/72 20130101;
C02F 1/682 20130101; C07C 43/2055 20130101; C10G 1/047 20130101;
C10G 1/04 20130101; C09K 3/32 20130101; C11D 1/04 20130101; C11D
1/08 20130101 |
Class at
Publication: |
510/188 ;
554/121; 568/608; 208/332; 208/390; 208/334 |
International
Class: |
C07C 43/205 20060101
C07C043/205; C10G 1/04 20060101 C10G001/04; C11D 1/722 20060101
C11D001/722; C10G 21/16 20060101 C10G021/16; C11D 1/04 20060101
C11D001/04; C07C 69/353 20060101 C07C069/353 |
Claims
1. A compound having the formula: ##STR00016## wherein Ar is a
substituted or unsubstituted aryl, arylalkyl or heteroaryl group; p
is 1 or 2; m and n are independently 0, 1, 2, 3, 4, or 5; each
G.sub.1 and G.sub.2 are independently absent, O, S, NR.sub.2,
(CO)O, O(CO), CO, CONR.sub.2, or NR.sub.2CO; each R.sub.2 is
independently H or a lower alkyl; each G.sub.3 is absent,
(CH.sub.2).sub.q or G.sub.1; q is 1, 2, 3, 4 or 5; R is a
hydrophilic group; R.sub.1 is a saturated or unsaturated
hydrophobic aliphatic group; wherein when p is 1, Ar is substituted
by OH, SH or NH.sub.2; and wherein when at least one G.sub.2 is
absent, G.sub.1 is other than O.
2. The compound of claim 1 wherein Ar is a substituted or
unsubstituted phenyl group.
3. The compound of claim 2 wherein p is 2.
4. The compound of claim 3 wherein each R is independently a COOH
or a hydrophilic polymer.
5. The compound of claim 4 wherein each R is independently a
polyethylene glycol or a polypropyleneoxide.
6. The compound of claim 4 wherein each R.sub.1 is independently
C.sub.5 to C.sub.18 alkyl, alkenyl or alkadienyl.
7. The compound of claim 6 wherein each R.sub.1 is a straight chain
C.sub.5 to C.sub.18 alkyl.
8. The compound of claim 7 wherein each G.sub.1 is independently O
or OCO.
9. The compound of claim 8 wherein each G.sub.2 is independently O
or OCO.
10. The compound of claim 9 wherein each G.sub.1 and G.sub.2 are
O.
11. The compound of claim 10 wherein each R is independently a
polyethylene glycol.
12. The compound having the formula: ##STR00017## wherein R.sub.5
is a hydrophilic group; and R.sub.4 is a saturated or unsaturated
hydrophobic aliphatic group.
13. A compound of claim 1, having the formula: ##STR00018## wherein
G.sub.1 is S, NR.sub.2, (CO)O, O(CO), CO, CONR.sub.2, and
NR.sub.2CO; each R.sub.2 is independently H or a lower alkyl;
R.sub.1 is a saturated or unsaturated hydrophobic aliphatic group;
R.sub.21, R.sub.22, R.sub.23, R.sub.24, and R.sub.25 are each
independently H, OH, halogen, C1-C5 alkyl, C1-C5 alkoxy, a
C.sub.3-C.sub.7-cycloalkyl group, a phenyl group optionally
substituted by hydroxyl, halogen, lower alkyl or lower alkoxy; or
Fragment I having the formula below: ##STR00019## wherein at least
one of R.sub.21, R.sub.22, R.sub.23, R.sub.24, and R.sub.25 is
selected from Fragment I or OH; or a salt thereof.
14. The compound of claim 13 wherein one of R.sub.21, R.sub.22,
R.sub.23, R.sub.24, and R.sub.25 is Fragment I.
15. The compound of claim 13 wherein m is 1.
16. The compound of claim 13 wherein each R.sub.1 is independently
a C.sub.5 to C.sub.18 alkyl, alkenyl or alkadienyl.
17. The compound of claim 13 wherein each R.sub.1 is independently
a straight chain C.sub.5 to C.sub.18 alkyl.
18. The compound of claim 13 wherein G.sub.1 is OCO.
19. A compound claim 1 having the formula: ##STR00020## wherein m
and R.sub.1 are as defined above.
20. A method for extracting oil from an oil mixture comprising: (a)
adding a compound of claim 1 to an oil mixture, and (b) collecting
the oil.
21. The method of claim 20 wherein the oil mixture comprises oil
sands, wherein said method further comprises adding water to the
mixture.
22. The method of claim 20 wherein the oil mixture is a waterborne
oil slick.
23. The method of claim 20 wherein the oil mixture formed by step
(a) is transported via a pipeline.
24. The method of claim 20 wherein step (a) occurs in an oil well
to enhance oil recovery.
25. A method of degreasing machinery used in oil or bitumen
production comprising cleaning the machinery with a composition
comprising a compound of claim 1.
26. A method of removing water and associated salts from oil,
comprising: (a) contacting the oil with a compound of claim 1, and
(b) separating the water from the oil.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 12/481,072 filed Jun. 9, 2009, which claims the benefit of U.S.
Provisional Application No. 61/060,004 filed Jun. 9, 2008. The
entire teachings of the above applications are incorporated herein
by reference.
FIELD OF THE APPLICATION
[0002] The application relates generally to surfactants useful for
petroleum applications.
BACKGROUND
[0003] A number of problems in the petroleum industry derive from
the viscosity, surface tension, hydrophobicity and density of crude
oil. Heavy crude oil in particular, having an API gravity of less
than 20 degrees, is difficult to transport due to its viscosity,
and is difficult to remove from surfaces to which it has adsorbed,
due to its hydrophobicity and immiscibility with water. Extra-heavy
crude oil or bitumen, having an API gravity of less than 10
degrees, is heavier than water, so that it can sink to the bottom
of a water formation, causing sub-surface contamination.
[0004] The properties of crude oil contribute to the limitations of
oil recovery from traditional oil fields. Conservative estimates
suggest that 30% of the technically recoverable oil in U.S. oil
fields is inaccessible due to the adsorption of the residual oil to
porous geologies. Technologies to unlock the oil in these so-called
"dead" wells presently involve the use of hot water injections with
expensive surfactants, chemistries that are applied to overcome the
hydrophobicity of the adsorbed oil so that it can be mobilized.
[0005] The properties of crude oil also contribute to the
difficulty of environmental remediation following, for example, an
oil spill onto a body of water. The high interfacial tension causes
the oil to float on the water and adhere to plants, animals and
soil. As the aromatic constituents of the oil evaporate, the
heavier residues can sink, contaminating the subsurface structures.
Current treatment of spilled oil on water surfaces relies on
time-consuming and expensive biological degradation of the oil.
Thick, adherent crude oil cause environmental problems in the oil
fields as well. Oil deposits attached to vehicles and equipment
must be cleansed with jets of hot water and caustics.
[0006] The viscosity of heavy crude oil makes the substance
difficult and expensive to transport to upgrading facilities.
Because of its viscosity, a significant amount of energy is
required to pump it through pipelines to a refinery. Furthermore,
the viscosity affects the speed at which the heavy crude oil can be
pumped, decreasing the overall productivity of an oil field.
Exploiting certain oil fields or other oil deposits may be
economically unfeasible to develop at present because of the
transportation-related costs.
[0007] Surfactants have been widely used in the petroleum industry
to ameliorate the effects of crude oil's physical properties.
Surfactant molecules consist of hydrophobic and hydrophilic parts.
Their amphiphilic nature allows them to be adsorbed at an oil/water
interface, forming micelles that allow the interfacial tension
between oil and water to be reduced.
[0008] Surfactants are sometimes used for desalting of crude oil.
Desalting refers to the process of removing salts from oil, making
the oil more suitable for further refining. The salts are typically
dissolved in water that is associated with oil, so the removal of
water has multiple benefits. The presence of water reduces the
energy content of oil, and it carries salts that can harm catalyst
performance or cause corrosion. Ethoxylated nonylphenols have been
used for desalting of crude oil, but these compounds pose hazards
to the environment.
[0009] Furthermore, surfactant technologies for the aforesaid
petroleum applications typically are expensive or must be used at
high concentrations. Additionally, demulsification can prove to be
difficult, as these surfactants are designed for emulsifying
purposes. Demulsification typically requires added materials and
steps to break up the emulsion, which increases the effective cost
of use. Furthermore, the salts present in nature can inactivate
many surfactant technologies. In addition, other surfactant
technologies for petroleum applications are tailored only to oils
of a limited composition.
[0010] The development of a technology that can provide emulsion
and favorable transport properties while maintaining the ability to
demulsify on demand, all under variable conditions of salinity,
remains unmet in the art. Such a technology would have wide
reaching impact across the oilfield chemical sector in applications
such as those mentioned above, particularly if the material could
be inexpensively produced and could be applied to a variety of oil
types.
SUMMARY
[0011] The invention relates to the discovery that novel
surfactants have good to excellent properties in recovering or
extracting oil, such as fossil fuels. Accordingly, in some
embodiments, the invention relates to a compound having the formula
I:
##STR00001##
wherein Ar is a substituted or unsubstituted aryl, aralkyl (e.g.,
benzyl) or heteroaryl group; in some embodiments, Ar is a
substituted or unsubstituted aryl, heteroaryl group, preferably a
substituted or unsubstituted phenyl group; p is 1 or 2, preferably
2; m and n are independently 0, 1, 2, 3, 4, or 5, preferably 1;
each of G.sub.1 and G.sub.2 are independently absent, O, S,
NR.sub.2, (CO)O, O(CO), CO, CONR.sub.2, or NR.sub.2CO; preferably
each G.sub.1 and G.sub.2 are independently O or C(O)O; each R.sub.2
is independently H or a lower alkyl; in some embodiments, the lower
alkyl is a C1 to C5 alkyl; each G.sub.3 is independently absent,
(CH.sub.2).sub.q or G.sub.1; q is 1, 2, 3, 4 or 5; R is a
hydrophilic group; preferably the hydrophilic group is COOH, or a
hydrophilic polymer, such as a polyethylene glycol or a
polypropyleneoxide; R.sub.1 is a saturated or unsaturated
hydrophobic aliphatic group; in some embodiments, R.sub.1 is
C.sub.5 to C.sub.18 alkyl, alkenyl or alkadienyl, preferably a
straight chain C.sub.5 to C.sub.18 alkyl; wherein, when p is 1, Ar
is substituted by one or more of OR.sub.2, SR.sub.2 and
N(R.sub.2).sub.2; preferably, when p is 1 Ar is substituted by OH,
SH or NH.sub.2.
[0012] In one preferred embodiment, G.sub.1 is C(O)O, G.sub.2 is
absent and n is 0. Alternatively, where G.sub.1 is O, G.sub.2 is
not absent, and is preferably O or (CO)O.
[0013] A particularly preferred surfactant is a compound having the
formula (II):
##STR00002##
wherein R.sub.5 is a hydrophilic group; and R.sub.4 is a saturated
or unsaturated hydrophobic aliphatic group.
[0014] The invention further relates to a compound having formula
III:
##STR00003##
wherein G.sub.1 is selected from the group consisting of S,
NR.sub.2, (CO)O, O(CO), CO, CONR.sub.2, and NR.sub.2CO; preferably
G1 is C(O)O; each R.sub.2 is independently H or a lower alkyl;
wherein, R.sub.21, R.sub.22, R.sub.23, R.sub.24, and R.sub.25 are
each independently, H, OH, halogen, C.sub.1-5 alkyl,
C.sub.1-C.sub.5 alkoxy, a C.sub.3-C.sub.7-cycloalkyl group, a
phenyl group optionally substituted by hydroxyl, halogen, lower
alkyl or lower alkoxy, or Fragment I having the formula shown
below:
##STR00004##
wherein R.sub.1, m and G.sub.1 are as defined above; wherein at
least one of R.sub.21, R.sub.22, R.sub.23, R.sub.24, and R.sub.25
is Fragment I or OH; or a salt thereof.
[0015] A particularly preferred surfactant is a compound having the
formula IV:
##STR00005##
wherein m and R.sub.1 are as defined above.
[0016] Preferred compounds of formula IV are compounds wherein m is
1 and R.sub.1 is a straight chain C.sub.5 to C.sub.18 alkyl.
[0017] The invention further relates to a method for extracting oil
from an oil mixture comprising:
[0018] (a) adding a compound of Formula I to an oil mixture,
and
[0019] (b) collecting the oil.
[0020] The oil mixture may comprise oil sands, waterborne oil
slicks or oil deposits. Further, the method can comprise the
additional steps of adding water or transporting the mixture via a
pipeline. In another embodiment, the compounds of the invention can
be used in methods of degreasing machinery, such as those used in
oil or bitumen production.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 illustrates examples of critical micelle
concentration of compounds of formulas shown below, termed R1 and
R2, on the graphs below.
[0022] FIG. 2 shows a plot of CMC as a function of pH for two
molecules, R1 and R2.
[0023] FIG. 3 compares the capabilities of the R1 and R2
surfactants in emulsifying and transporting heavy crude oils,
measuring the viscosity of diluted bitumen.
DETAILED DESCRIPTION
General Formulations
[0024] Disclosed herein are compositions, systems and methods
related to ultra-low interfacial tension ("IFT") surfactants for
applications in the petroleum industry. In certain embodiments, the
present disclosure is based on the discovery that certain
resorcinol-based ester surfactants are highly effective surfactants
for petroleum applications, and can be used as additives in
petroleum processing, oil sands extraction and processing,
environmental remediation, enhanced oil recovery, and the like. In
one embodiment, compositions of particular use in these systems and
methods can include at least one compound of the formula (V):
##STR00006##
wherein R.sub.1 is a hydrophobic group as defined above.
[0025] In alternate embodiments, compositions of particular use in
these systems and methods can include at least one compound of
formula (VI):
##STR00007##
[0026] In one embodiment, compositions of particular use in these
systems and methods can include at least one compound of the
formula (VII):
##STR00008##
wherein R.sub.6 and R.sub.7 are each independently a hydrophobic
group and R.sub.1 is as defined above.
[0027] The compounds described herein can be used as surfactants.
The inventive surfactant compounds comprise an aromatic core with
pendant aliphatic hydrophobic and hydrophilic portions. As will be
understood by one of skill in the art the hydrophobic portion of
the surfactant compound can comprise one or more hydrophobic groups
or substituents. Similarly, the hydrophilic portion of the
inventive compounds can comprise one or more hydrophilic groups or
substituents. Attached aliphatic hydrophobic portions or groups can
consist of linear or branched, saturated or unsaturated,
substituted or unsubstituted higher alkyls. For example, the
hydrophobic group can be derived from alkanes with or without
internal or terminal alkenes. In some embodiments, the higher alkyl
comprises at least five carbon atoms. In other embodiments, the
higher alkyl is a C.sub.5 to C.sub.18 alkyl, alkenyl or alkadienyl.
Hydrophilic portions or groups can be an ionizable groups,
including, for example, amines and carboxylic acids. Hydrophilic
groups also include hydrophilic polymers, including, but not
limited to, polyalkylamine, poly(ethylene glycol) or poly(propylene
glycol). Nonionic hydrophilic materials such as polyalkylamine,
poly(ethylene glycol) or poly(propylene glycol) can be used to
increase hydrophilicity or aid stability in salt solutions.
[0028] In some embodiments, the aliphatic groups include saturated
or unsaturated carbon chains, preferably between five and eighteen
units in length, or hydrogen. The carbon chains can optionally be
unsaturated and, when present, reside anywhere along the carbon
chain.
[0029] The aromatic core can be carbocyclic or heterocyclic,
monocyclic or polycyclic, substituted or unsubtstituted. Preferred
aryl groups can be derived from resorcinol, phenol, creosol, benzyl
alcohol, naphthalene, anthracene, pyrene, tetrahydronaphthyl,
indanyl, idenyl and the like. Heteroaromatic structures such as
thiophene, selenophene, silole, pyrrole, pyridine, furan,
imidazole, indole, pyrazinyl, pyrimidinyl, pyrazolyl, imidazolyl,
thiazolyl, oxazolyl, isooxazolyl, thiadiazolyl, oxadiazolyl,
furanyl, quinolinyl, isoquinolinyl, benzimidazolyl, benzooxazolyl,
quinoxalinyl, and the like can also be used as the aromatic core.
The term "substituted" refers to substitution by independent
replacement of one or more of the hydrogen atoms thereon with
substituents including, but not limited to, --OH, --NH.sub.2,
--NH--C.sub.1-C.sub.12-alkyl, --O--C.sub.1-C.sub.12-alkyl, --SH,
and --S--C.sub.1-C.sub.12-alkyl.
[0030] In certain aspects of the invention, the hydrophilic portion
of compounds of the invention is one or more ionizable carboxylic
acid groups, which groups make up the totality of the hydrophilic
portion. By themselves, the carboxylic acid portions are not enough
to effectively stabilize emulsions formed by the mixture of a
waterborne suspension of the disclosed surfactant compounds.
Addition of a small amount of base (greater than pH 8) is
sufficient to ionize, leaving a more active, emulsion-forming
material. The emulsion can later be destabilized by adding acid to
the material, removing the charge stabilization and splitting the
two incompatible phases.
[0031] Changing pH is one method to enabling and disabling the
surfactant behavior; however, compounds of formula (I) and formula
(III) are typically unstable hydrolytically. For example, in
certain embodiments, exposure to base for prolonged periods of time
will degrade the compounds of formula (I) and formula (III) to
resorcinol and alkylated succinic acid. The decomposition
byproducts have little to no surfactant behavior, and thus can be
utilized as another means to destabilize the formed emulsion. The
disintegration follows a predictable profile which can be exploited
for tunable, time-based demulsion.
[0032] This behavior has utility for petroleum-related
applications. If one knows, for example, the residence time of oil
in a pipeline, the amount of base can be precisely calculated and
added to cause decomposition begin in the pipeline and separation
to occur immediately after the emulsion reaches its destination.
This has the benefit of decreasing residence time in a storage
facility while the emulsion breaks.
Applications
[0033] Environmental Remediation
[0034] By taking advantage of the low IFT behavior of the
surfactant families disclosed herein, such surfactants may be
suitable for applications where undesired petroleum products pose
an environmental problem. Oil cleanup using surfactants may be
required for two different types of contamination. First, as an oil
slick dispersant, the surfactant family can be used on waterborne
slicks, acting as a dispersing agent. It will act to disperse the
oil into the water body itself and encourage biodegradation through
natural decomposition means. Additionally, a solution of surfactant
can be used to remove physisorbed crude or refined oils from
inorganic rocks, sand, or other substrates as an emulsion.
[0035] Oil Sands Extraction
[0036] Oil sands comprise heavy petroleum products coating sand and
clay, an assemblage that is similar to certain artificial
composites that are formed during a man-made oil spill, as
described above. The systems and methods described herein may be
useful for extracting bitumen from the other components of the tar
sands material. Currently, mined oil sands are extracted using hot
water, a process that causes the less dense bitumen to flow off the
sand and float to the surface of a settling tank. This so-called
"primary froth" is contaminated with various materials derived from
the mined products (solid particles, clay, and sand). Current froth
treatment utilizes naphtha, a valuable fraction of purified
petroleum, to dilute the bitumen and decrease the viscosity to the
point of flowability. This allows solids and water to be removed by
settling and centrifugation methods. By using an aqueous solution
of surfactant as the dilution medium instead of naphtha, the latter
solvent can be replaced with water and surfactant, thus decreasing
the cost of purifying the froth. Additionally, when the
surfactant-diluted bitumen is recovered from the water, the
hydrophilic portions associated with the froth (clay, water, salts)
will preferentially partition to the water phase and be separable
from the bitumen.
[0037] Use of surfactants in accordance with these systems and
methods may further be applied to other aspects of the extraction
process, for example in the oil sands strip mining or in-situ
operations, where the ability to emulsify the petroleum component
of the oil sands ore may enhance the efficiency or economy of
separating the bitumen from the insoluble byproducts.
[0038] Oil Field Transport Emulsions
[0039] Transporting petroleum precursors for further processing is
a necessary, though expensive, part of obtaining usable crude oil.
When petroleum is obtained as a heavy crude, it needs to be
transported to an upgrading facility for conversion to useful
petroleum products. Typically, pipeline transport is the most
economical means to accomplish this. When oil sands are used as
precursors in the production of synthetic crude oil, they are
transported for further processing after extraction and froth
treatment through pipelines as a naphtha-diluted bitumen so that
they can undergo further upgrading processes, including cracking
and coking, amongst other standard refining operations. For these
types of applications in the petroleum and tar sands industries,
the heavy oil or oil precursor materials (respectively) may be
transported through pipelines as oil-in-water mixtures or
emulsions. It is understood that more viscous matter being sent
through pipelines has a greater resistance to flow and consequently
requires more energy to move an equivalent distance. Hence,
decreasing the viscosity of the flowable matter decreases the
amount of pumping energy required, and potentially improves the
transit time and the productivity of the overall process. Mixing
water with crude oil or bitumen can decrease the viscosity of these
latter substances towards the viscosity of water, but only if a
water-continuous emulsion is created. The described low IFT
surfactants can compatibilize oil and water into an emulsion that
can be pumped with greatly decreased energy requirements and/or
increase the throughput of crude oil or oil precursors to their
destinations.
[0040] Auxiliary Petroleum Applications
[0041] There also exist many other opportunities in the oilfield
chemical sector for degreasing applications, as can be accomplished
with the systems and methods disclosed herein. Periodically,
machinery used in oil and bitumen production must be cleaned for
maintenance and performance reasons. With petroleum production
heading towards heavier crude reserves, the need for an effective
degreaser becomes even more acute: exposure to heavier crude oils
results in thicker, more adherent oil residues that must be removed
during the cleaning/degreasing processes. The described low IFT
surfactants can be an active ingredient in an industrial degreasing
formulation for these purposes.
[0042] Enhanced Oil Recovery (EOR)
[0043] Tertiary oil recovery, also known as "enhanced" or
"improved" oil recovery, makes use of low IFT polymers to produce
oil from wells that have stopped producing of their own accord.
Injection of a low IFT surfactant into one of these less productive
wells can stimulate production from the residual oil left adhered
to the surface of porous rocks. Compounds produced according to
these systems and methods are useful as low IFT surfactants for
EOR. Due to the temperatures and residence time underground,
certain esters made in accordance with formula (I) or formula (II)
may be too unstable for these applications. In addition, the
resident acid groups on the compound of formula (II) are highly
sensitive to saline commonly found in well formations.
[0044] The compound of formula (III) may be particularly suitable
for EOR applications:
##STR00009##
[0045] R.sub.4 and R.sub.5 are as defined above.
[0046] In some embodiments, R.sub.4 can include a linear or
branched carbon chain consisting of five to eighteen carbon atoms.
Advantageously, substituent R.sub.4 can be a saturated or
unsaturated carbon chain consisting of five to eighteen carbon
atoms.
[0047] In some embodiments, R.sub.5 can include water soluble
oligomers such as poly(ethylene glycol) or polypropylene oxide). By
using a small poly(ethylene glycol) as the hydrophilic portion the
substituent R.sub.5, and all ether connectivity, the molecule of
formula (II) may desirably withstand the temperature and salinities
found underground for the requisite time period.
[0048] Desalting
[0049] Desalting refers to the process of removing salts from oil,
making the oil more suitable for further refining. Salts, including
magnesium chloride, sodium chloride and calcium chloride can be
found in crude oil. If allowed to remain in the crude oil during
the refinery operation, the salts can dissociate and the chloride
ion can ionize to form hydrochloric acid, which, along with various
organic acids found in crude oil, contributes to corrosion in
refinery equipment. In addition, other metal salts (e.g.,
potassium, nickel, vanadium, copper, iron and zinc) can be found in
the crude oil, also contributing to fouling of the equipment and
end-product degradation. Crude oil also contains emulsified water,
which contains dissolved salts.
[0050] Desalting crude oil takes advantage of the fact that the
salts dissolve in a water phase, which is separable from the oil
phase. Crude oil naturally contains water in emulsion, as mentioned
above. For certain techniques of desalting, additional water may be
added to the oil (e.g., in an amount between 5-10% by volume of
crude) so that the impurities can further dissolve in the water.
The water-in-oil emulsion can be broken with the assistance of
emulsion-breaking chemicals and/or by exposing the emulsion to an
electrical field that polarizes the water phase, so that the water
phase bearing the impurities separates from the petroleum phase.
Ethoxylated nonylphenols are a class of nonionic surfactants that
have been used for desalting crude oil according to these
principles.
[0051] The surfactant families disclosed herein can facilitate the
demulsification of the water-in-oil emulsion, so that the oil phase
separates from the water phase, with the water phase carrying the
soluble impurities (i.e., the salts). In embodiments, the
hydrophilic portion of the surfactant compound can include one or
more ionizable carboxylic acid groups that can be ionized at a
basic pH (e.g., >8) to produce an emulsion-sustaining material.
To destabilize the emulsion, acid may be added, removing the charge
stabilization and allowing the two phases to segregate from each
other.
EXAMPLES
Example 1
Synthesis of Compounds of Formula (I)
[0052] Compounds having the structure of formula (I) may be
synthesized as follows:
[0053] A 300 ml bomb is charged with resorcinol (5 g, 48 mmol) and
Eka SA 210 brand alkylated succinic anhydride (100% C18 chain, 16.8
g., 48 mmol). To this, acetone (150 ml) is added, the vessel is
sealed and heated to 80.degree. C. for 16 hours. After the reaction
is complete, acetone is removed in vacuo and the remaining amber
oil is collected in quantitative yield. The scheme below
illustrates this Synthesis I.
##STR00010##
Example 2
Synthesis of Compounds of Formula (II)
[0054] Compounds having the structure of formula (II) may be
synthesized as follows:
[0055] A 300 ml bomb is charged with resorcinol (5 g, 48 mmol) and
Eka SA 210 brand alkylated succinic anhydride (100% C.sub.18 chain,
33.7 g, 96 mmol). To this, acetone (150 ml) is added, the vessel
sealed, and heated to 80.degree. C. for 16 hours. After the
reaction is completed, acetone is removed in vacuo and the
remaining amber oil is collected in quantitative yield. The scheme
below illustrates this Synthesis II.
##STR00011##
Example 3
Proposed Synthesis of Compounds of Formula (II)
[0056] Compounds having the structure of formula (II) may be
synthesized as follows:
[0057] A 300 ml bomb is charged with resorcinol (5 g, 48 mmol) and
glycidyl hexadecyl ether (28.6 g, 96 mmol). To this, acetone (150
ml) is added, the vessel sealed, and the mixture heated to
80.degree. C. for 16 hours. After this first addition, the material
is isolated and dried under vacuum. The alcohol moieties created by
the epoxide ring opening is used as initiators in an ethylene oxide
polymerization to create a hydrophilic portions on the surfactant,
under standard ethylene oxide polymerization conditions. The scheme
below illustrates this Synthesis III:
##STR00012##
Example 4
Proposed Synthesis of Compounds of Formula (II)
[0058] Compounds having the structure of formula (III) may be
synthesized as follows:
[0059] A 300 ml bomb is charged with resorcinol (5 g, 48 mmol) and
glycidyl hexadecyl ether (14.3 g, 48 mmol). To this, acetone (150
ml) is added, the vessel sealed, and the mixture heated to
80.degree. C. for 16 hours. After this first addition, the material
is isolated and dried under vacuum. The alcohol moieties created by
the epoxide ring opening is used in the next reaction to add
hydrophilic portions to the molecule. Compound 1 is dissolved in
acetone and heated to 80.degree. C. to complete the reaction
without the need for an ethylene oxide polymerization. The scheme
below illustrates this Synthesis IV.
##STR00013##
Example 5
Critical Micelle Concentration
[0060] Critical micelle concentration (CMC) is an important metric
with surfactant systems. It is defined as the minimum surfactant
concentration that will form micelles. Below this amount, the
molecules exist only in a non-aggregated form. Additionally, this
number also represents the constant concentration of monomeric
molecules in solution. Effectively, it describes a lower limit to
usage and is a good first approximation to formulation content.
[0061] A series of aqueous surfactant dilutions were prepared in
deionized water with concentrations between 20 .mu.M and 200 mM.
The water surface tension at 22.degree. C. was measured on a KSV
702 tensiometer using the Du Nouy ring method. Measured surface
tensions were plotted against concentration and linear regression
analysis was used to find the inflection point denoting the
critical micelle concentration (CMC) of the surfactant. For testing
at higher or lower pH conditions, 0.1 M buffer solutions were used.
Citric acid buffer was used to stabilize pH 3 while sodium
bicarbonate was used for a pH 10 buffer.
[0062] FIG. 1 illustrates examples of critical micelle
concentration of a compound of formula shown below, termed R1 on
the graphs below. R1 is a species of a compound of formula (I).
FIG. 1 also illustrates examples of critical micelle concentration
of a compound of formula shown below, termed R2 on the graphs
below.
##STR00014##
[0063] FIG. 2 shows a plot of CMC as a function of pH for two
molecules, R1 (shown above) and a compound of formula (V), termed
R2 in the graphs below. R2 is a species of a compound of formula
(II).
##STR00015##
Example 6
Emulsion Stability for Oil Flow Behavior
[0064] In order to test the capabilities of the surfactants in
emulsifying and transporting heavy crude oils, the viscosity was
measured with various additions of surfactant solution on a
Brookfield viscometer at 22.degree. C. Compounds of formula (VI),
designated as R1, and compounds of formula (VII), designated as R2,
were tested. Using a LV3 type spindle at 40 RPM, the diluted
bitumen (residual toluene mixed with bitumen) demonstrated a
viscosity of approximately 2000 cP. This diluted bitumen was then
mixed with multiple ratios of a 1 wt % solution of R1 or R2 in
deionized water with the pH adjusted to 9 for emulsion activity.
FIG. 3 illustrates the results of these tests, showing the
viscosity of diluted bitumen as a function of surfactant solution
addition.
[0065] FIG. 3 demonstrates that incorporation of an aqueous
solution of surfactant can dramatically decrease the viscosity of
diluted bitumen. As shown in FIG. 3, the addition of more than 50
vol % of a dilute aqueous solution of R1 or R2 decreases the
bitumen viscosity by nearly one thousand times. The energy savings
of such a system are significant, but the concomitant increase in
flowrate enables much higher throughput and residence time in a
pipeline.
EQUIVALENTS
[0066] While specific embodiments of the subject invention have
been discussed, the above specification is illustrative and not
restrictive. Many variations of the invention will become apparent
to those skilled in the art upon review of this specification.
Unless otherwise indicated, all numbers expressing quantities of
ingredients, reaction conditions, and so forth used in the
specification and claims are to be understood as being modified in
all instances by the term "about." Accordingly, unless indicated to
the contrary, the numerical parameters set forth herein are
approximations that can vary depending upon the desired properties
sought to be obtained by the present invention.
[0067] While this invention has been particularly shown and
described with references to preferred embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and details may be made therein without departing from the
scope of the invention encompassed by the appended claims.
* * * * *