Note: Descriptions are shown in the official language in which they were submitted.
CA 02904728 2015-09-17
POLYMERS AND EMULSIONS FOR USE IN OIL AND/OR GAS WELLS
Field of Invention
Methods and compositions comprising an emulsion or a microemulsion and a
polymer for use in an oil and/or gas well are provided.
Background of Invention
For many years, petroleum has been recovered from subterranean reservoirs
through the use of drilled wells and production equipment. Oil and natural gas
are found
in, and produced from, porous and permeable subterranean formations, or
reservoirs. The
porosity and permeability of the formation determine its ability to store
hydrocarbons,
and the facility with which the hydrocarbons can be extracted from the
formation.
Generally, the life cycle of an oil and/or gas well includes drilling to form
a wellbore,
casing, cementing, stimulation, and enhanced or improved oil recovery.
Various aspects of the life cycle of an oil and/or gas well are designed to
facilitate
the extraction of oil and/or gas from the reservoir via the wellbore. For
example,
enhanced oil recovery (EOR) can be used to further recover hydrocarbons from a
wellbore. EOR methods include but are not limited to gas flooding (CO2, N2,
and
hydrocarbons and/or solvents), thermal flooding (steam injection, SAGD (steam
assisted
gravity drainage), etc.), and chemical flooding (Polymer Flooding, surfactant
flooding,
alkali surfactant polymer flooding). Polymer flooding is growing as a result
of the
limitations associated with the alternative EOR methods.
When selecting or using a fluid to be utilized during the life cycle of an oil
and/or
gas well, it is important for the fluid to comprise the right combination of
additives and
components to achieve the necessary characteristics of the specific end-use
application.
A primary goal amongst all aspects of the life cycle of a well is to optimize
recovery of
oil and/or gas from the reservoir. However, in part because the fluids
utilized during the
life cycle of an oil and/or gas well are often utilized to perform a number of
tasks
simultaneously, achieving the necessary optimal characteristics is not always
easy.
Accordingly, it would be desirable if a wide variety of additives were
available
which could be selected from to achieve the necessary characteristics and/or
could be
easily adapted. Furthermore, it is desirable that the additives provide
multiple benefits
and are useful across multiple portions of the life cycle of the well. The use
of
- 1 -
microemulsions has been employed, however, selection of an appropriate
microemulsion for
a particular application remains challenging, as well as there is a continued
need for
emulsions with enhanced abilities.
Accordingly, although a number of additives are known in the art, there is a
continued need for more effective additives for increasing production of oil
and/or gas.
Summary of Invention
Methods and compositions comprising an emulsion or a microemulsion and a
polymer for use in an oil and/or gas well are provided.
to In one aspect, methods of treating an oil and/or gas well having a
wellbore are
provided. In some embodiments, the method comprises injecting a water flooding
fluid
comprising a polymer and an emulsion or microemulsion into the wellbore,
wherein the
emulsion or microemulsion comprises water, a surfactant, and a solvent.
In another aspect, compositions for use in an oil and/or gas well having a
wellbore
t 5 are provided. In some embodiments, the composition comprises a polymer
and an emulsion
or microemulsion, wherein the emulsion or the microemulsion comprises an
aqueous phase,
a surfactant, and a solvent.
Other aspects, embodiments, and features of the methods and compositions will
become apparent from the following detailed description when considered in
conjunction
20 with the accompanying drawings.
Brief Description of the Drawings
The accompanying drawings are not intended to be drawn to scale. For purposes
of
clarity, not every component may be labeled in every drawing. In the drawings:
25 FIG. 1 shows an exemplary plot for determining the phase inversion
temperature of a
microemulsion, according to some embodiments;
FIG. 2 shows a schematic of the CMG-STARS simulation model wells and layers
and the permeability (in mD) of the layers;
FIG. 3A is a plot of the simulated oil recovery rate (in bbl/day) versus time
(in days)
30 for waterflooding in the presence or absence of water, polymer, and/or
microemulsion (ME),
according to some embodiments;
- 2 -
CA 2904728 2018-01-10
CA 02904728 2015-09-17
FIG. 3B is a plot of the simulated cumulative oil (in bbl) versus time (in
days) for
waterflooding in the presence or absence of water, polymer, and/or
microemulsion (ME),
according to some embodiments;
FIG. 3C is a plot of the simulated fraction of water cut versus time (in days)
for
waterflooding in the presence or absence of water, polymer, and/or
microemulsion (ME),
according to some embodiments; and
FIGs. 4A-4E are plots of the simulated oil saturation of a layer of the model
after
simulated waterflooding in the presence or absence of water, polymer, and/or
microemulsion (E/ME), according to some embodiments.
to
Detailed Description
Methods and compositions comprising an emulsion or a microemulsion and a
polymer for use in an oil and/or gas well are generally provided. In some
embodiments,
the composition is a water flooding fluid (e.g., a polymer flooding fluid)
used in
enhanced oil recovery and/or improved oil recovery operations. In some such
embodiments, the water flooding fluid may comprise a polymer and an emulsion
or
microemulsion.
In some embodiments, the polymer is a copolymer. The emulsion or
microemulsion may comprise, for example, an aqueous phase (e.g., water in an
amount
between about 1 wt% and about 60 wt% versus the total emulsion or
microemulsion
composition), a surfactant (e.g., a surfactant present in the emulsion or
microemulsion in
an amount ranging between about 5 wt% and about 65 wt% versus the total
emulsion or
microemulsion composition), and a solvent (e.g., a solvent present in the
emulsion or
microemulsion in an amount ranging between about 1 wt% and about 30 wt% versus
the
total emulsion or microemulsion composition). Solvents are described in more
detail,
below. In some embodiments, the solvent may comprise a fatty acid ester
solvent and/or
a terpene solvent. Fatty acid ester solvents and terpene solvents are
described in more
detail, below. Suitable surfactants for use in an emulsion or microemulsion
are also
described below. In some cases, the emulsion or microemulsion comprises an
alcohol
(e.g., isopropyl alcohol, methanol), as described below. Additional details
regarding the
emulsions or microemulsions, as well as the applications of the emulsions or
microemulsions, are described below.
- 3 -
CA 02904728 2015-09-17
In some embodiments, the composition comprising a polymer and an emulsion or
a microemulsion is added to a water flooding fluid thereby increasing
hydrocarbon (e.g.,
liquid or gaseous) production of the well, improving recovery of the fluid
and/or other
fluids, and/or preventing or minimizing damage to the well caused by exposure
to the
fluid (e.g., from imbibition), as compared to, for example, traditional water
and/or
polymer flooding fluids.
In some embodiments, the composition comprises a polymer such as acrylamide
(e.g., polyacrylamide). In certain embodiments, the polymer is a copolymer.
The
copolymer may be, in some cases, a copolymer of a first monomer and a second
monomer. In some embodiments, the first monomer comprises acrylamide. In
certain
embodiments, the polymer is formed by the copolymerization of the first
monomer and
the second monomer such that a copolymer comprising the first monomer and
second
monomer is formed.
In certain embodiments, the second monomer comprises an anionic monomer.
Non-limiting examples of suitable anionic monomers include
acrylamidopropanesulfonic
acid, acrylic acid, methacrylic acid, monoacryloxyethyl phosphate, and alkali
metal salts
thereof Those skilled in the art would be capable of selecting additional
anionic
monomers for use with a water flood fluid based upon the teachings of this
specification.
In some embodiments, the second monomer comprises a cationic monomer.
Non-limiting examples of suitable cationic monomers include
dimethylaminoethylacrylate methyl chloride quaternary salt,
diallyldimethylammonium
chloride, (3-acrylamidopropyl)trimethylammonium chloride, (3-
methacrylamido)propyltrimethylammonium chloride,
dimethylaminoethylmethacrylate
methyl chloride quaternary salt, and dimethylaminoethylacrylate benzylchloride
quaternary salt. Those skilled in the art would be capable of selecting
additional cationic
monomers for use with a water flood fluid based upon the teachings of this
specification.
In some embodiments, the second monomer comprises a nonionic monomer.
Non-limiting examples of suitable nonionic monomers include acrylamide,
methacrylamide, N-methylacrylamide, N,Ndimethyl(meth)acrylamide, octyl
acrylamide,
N(2 hydroxypropyl)methacrylamide, Nmethylolacrylamide, N-vinylformamide, N-
vinylacetamide, N-vinyl-N-methylacetamide, poly(ethylene
glycol)(meth)acrylate,
poly(ethylene glycol) monomethyl ether mono(meth)acrylate, N-vinyl-2-
pyrrolidone,
glycerol mono((meth)acrylate, 2 hydroxyethyl (meth)acrylate, vinyl
methylsulfone, and
- 4 -
CA 02904728 2015-09-17
vinyl acetate. Those skilled in the art would be capable of selecting
additional nonionic
monomers for use with a water flood fluid based upon the teachings of this
specification.
In certain embodiments, the second monomer comprises a zwitterionic monomer.
Non-limiting examples of suitable zwitterionic monomers include N,N-dimethyl-N-
acryloyloxyethynyl-N-(3-sulfopropy1)-ammonium betaine, N,N-dimethyl-N-
acrylamidopropyl-N-(2-carboxymethyl)-ammonium betaine, N,N-dimethyl-N-
methacrylcryloyloxyethynyl-N-(3-sulfopropy1)-ammonium betaine, N,N-dimethyl-N-
methacrylcryloyloxyethynyl-N-(3-sulfopropy1)-sulfoneum betaine, 2-
(methylthio)ethyl
methacryloyl-S-(sulfopropy1)-sulfonium betaine, 2 [(2
acryloylethyl)dimethylammonio]ethyl 2-methyl phosphate, 2-(acryloyloxyethyl)-
2'(trimethylammonium)ethyl phosphate, and [(2-
acryloylethyl)dimethylammonio]methyl
phosphonic acid. Additional zwitterionic monomers are described in, for
example, U.S.
Pat. No. 6,709,551, incorporated herein by reference. Those skilled in the art
would be
capable of selecting additional zwitterionic monomers for use with a water
flood fluid
based upon the teachings of this specification.
In some embodiments the first monomer is present in the copolymer in an amount
ranging between about 60 wt% and about 99 wt% versus the total weight of the
copolymer, and the second monomer is present in the copolymer in an amount
ranging
between about 1 wt% and about 40 wt% versus the total weight of the copolymer.
For
example, in some embodiments, the first monomer (e.g., acrylamide) is present
in the
copolymer in an amount of at least about 60 wt%, at least about 70 wt%, at
least about
80 wt%, at least about 90 wt%, at least about 95 wt%, or at least about 98 wt%
versus the
total copolymer composition. In certain embodiments, the first monomer is
present in
the copolymer is an amount of less than or equal to about 99 wt%, less than or
equal to
about 98 wt%, less than or equal to about 95 wt%, less than or equal to about
90 wt%,
less than or equal to about 80 wt%, or less than or equal to about 70 wt%
versus the total
copolymer composition. Combinations of the above-referenced ranges are also
possible
(e.g., between about 60 wt% and about 99 wt%). Other ranges are also possible.
In certain embodiments, the second monomer is present in the copolymer in an
amount of at least about 1 wt%, at least about 2 wt%, at least about 5 wt%, at
least about
10 wt%, at least about 20 wt%, or at least about 30 wt% versus the total
copolymer
composition. In some embodiments, the second monomer is present in the
copolymer in
an amount of less than or equal to about 40 wt%, less than or equal to about
30 wt%, less
- 5 -
CA 02904728 2015-09-17
than or equal to about 20 wt%, less than or equal to about 10 wt%, less than
or equal to
about 5 wt%, or less than or equal to about 2 wt% versus the total copolymer
composition. Combinations of the above-referenced ranges (e.g., between about
1 wt%
and about 40 wt%) are also possible. Other ranges are also possible.
In some embodiments, the polymer (e.g., the copolymer) may have a number
average molecular weight ranging between about 10,000 Daltons and about
50,000,000
Daltons. For example, in some embodiments, the number average molecular weight
of
the polymer may be at least about 10,000 Daltons, at least about 50,000
Daltons, at least
about 75,000 Daltons, at least about 100,000 Daltons, at least about 500,000
Daltons, at
least about 1,000,000 Daltons, at least about 5,000,000 Daltons, at least
about
10,000,000 Daltons, or at least about 25,000,000 Daltons. In certain
embodiments, the
number average molecular weight of the polymer is less than or equal to about
50,000,000 Daltons, less than or equal to about 25,000,000 Daltons, less than
or equal to
about 10,000,000 Daltons, less than or equal to about 5,000,000 Daltons, less
than or
equal to about 1,000,000 Daltons, less than or equal to about 500,000 Daltons,
less than
or equal to about 100,000 Daltons, less than or equal to about 75,000 Daltons,
or less
than or equal to about 50,000 Daltons. Combinations of the above-referenced
ranges are
also possible (e.g., between about 10,000 Daltons and about 50,000,000
Daltons,
between about 50,000 Daltons and about 25,000,000 Daltons, between about
75,000
Daltons and about 10,000,000 Daltons). Other ranges are also possible. Those
skilled in
the art would be capable of selecting suitable methods for determining the
molecular
weight of a polymer including, for example, size exclusion chromatography
and/or small
angle laser light scattering.
In certain embodiments, the polymer may be present in the water flooding fluid
in any suitable concentration. For example, in some embodiments, the polymer
is
present in the water flooding fluid at a concentration ranging between 1 and
1,000,000
parts per million (ppm). In some embodiments, the polymer is present in the
water
flooding fluid at a concentration of at least about 1 ppm, at least about 100
ppm, at least
about 500 ppm, at least about 1,000 ppm, at least about 5,000 ppm, at least
about 10,000
ppm, or at least about 50,000 ppm. In certain embodiments, the polymer is
present in the
water flooding fluid at a concentration of less than or equal to about 100,000
ppm, less
than or equal to about 50,000 ppm, less than or equal to about 10,000 ppm,
less than or
equal to about 5,000 ppm, less than or equal to about 1,000 ppm, less than or
equal to
- 6 -
CA 02904728 2015-09-17
about 500 ppm, less than or equal to about 100 ppm, or less than or equal to
about 10
ppm. Combinations of the above-referenced ranges are also possible (e.g.,
between
about 1 and about 100,000 ppm, between about 100 and about 50,000 ppm, between
about 500 and about 10,000 ppm). Other ranges are also possible.
In some embodiments, emulsions or microemulsion are provided. The terms
should be understood to include emulsions or microemulsions that have a water
as
continuous phase, or that have an oil as continuous phase, or microemulsions
that are
bicontinuous or multiple continuous phases of water and oil.
As used herein, the term emulsion is given its ordinary meaning in the art and
refers to dispersions of one immiscible liquid in another, in the form of
droplets, with
diameters approximately in the range of 100-1,000 nanometers. Emulsions may be
thermodynamically unstable and/or require high shear forces to induce their
formation.
As used herein, the term microemulsion is given its ordinary meaning in the
art
and refers to dispersions of one immiscible liquid in another, in the form of
droplets,
with diameters approximately in the range of about between about 1 and about
1000 nm,
or between 10 and about 1000 nanometers, or between about 10 and about 500 nm,
or
between about 10 and about 300 nm, or between about 10 and about 100 nm.
Microemulsions are clear or transparent because they contain particles smaller
than the
wavelength of visible light. In addition, microemulsions are homogeneous
thermodynamically stable single phases, and form spontaneously, and thus,
differ
markedly from thermodynamically unstable emulsions, which generally depend
upon
intense mixing energy for their formation. Microemulsions may be characterized
by a
variety of advantageous properties including, by not limited to, (i) clarity,
(ii) very small
particle size, (iii) ultra-low interfacial tensions, (iv) the ability to
combine properties of
water and oil in a single homogeneous fluid, (v) shelf life stability, and
(vi) ease of
preparation.
In some embodiments, the microemulsions described herein are stabilized
microemulsions that are formed by the combination of a solvent-surfactant
blend with an
appropriate oil-based or water-based carrier fluid. Generally, the
microemulsion forms
upon simple mixing of the components without the need for high shearing
generally
required in the formation of ordinary emulsions. In some embodiments, the
microemulsion is a thermodynamically stable system, and the droplets remain
finely
- 7 -
CA 02904728 2015-09-17
dispersed overtime. In some cases, the average droplet size ranges from about
10 nm to
about 300 nm.
It should be understood, that while much of the description herein focuses on
microemulsions, this is by no means limiting, and emulsions may be employed
where
appropriate.
In some embodiments, the emulsion or microemulsion is a single emulsion or
microemulsion. For example, the emulsion or microemulsion comprises a single
layer of
a surfactant. In other embodiments, the emulsion or microemulsion may be a
double or
multilamellar emulsion or microemulsion. For example, the emulsion or
microemulsion
comprises two or more layers of a surfactant. In some embodiments, the
emulsion or
microemulsion comprises a single layer of surfactant surrounding a core (e.g.,
one or
more of water, oil, solvent, and/or other additives) or a multiple layers of
surfactant (e.g.,
two or more concentric layers surrounding the core). In certain embodiments,
the
emulsion or microemulsion comprises two or more immiscible cores (e.g., one or
more
of water, oil, solvent, and/or other additives which have equal or about equal
affinities
for the surfactant).
In some embodiments, a microemulsion comprises water, a solvent, and a
surfactant. In some embodiments, the microemulsion further comprises
additional
components, for example, a freezing point depression agent. Details of each of
the
components of the microemulsions are described in detail herein. In some
embodiments,
the components of the microemulsions are selected so as to reduce or eliminate
the
hazards of the microemulsion to the environment and/or the subterranean
reservoirs.
In some embodiments, the emulsion or microemulsion may be present in the
water flooding fluid in any suitable concentration. For example, in some
embodiments,
the emulsion or microemulsion is present in the water flooding fluid at a
concentration
ranging between 1 and 1,000,000 parts per million (ppm). In some embodiments,
the
emulsion or microemulsion is present in the water flooding fluid at a
concentration of at
least about 1 ppm, at least about 100 ppm, at least about 500 ppm, at least
about 1,000
ppm, at least about 5,000 ppm, at least about 10,000 ppm, or at least about
50,000 ppm.
In certain embodiments, the emulsion or microemulsion is present in the water
flooding
fluid at a concentration of less than or equal to about 100,000 ppm, less than
or equal to
about 50,000 ppm, less than or equal to about 10,000 ppm, less than or equal
to about
5,000 ppm, less than or equal to about 1,000 ppm, less than or equal to about
500 ppm,
- 8 -
CA 02904728 2015-09-17
less than or equal to about 100 ppm, or less than or equal to about 10 ppm.
Combinations of the above-referenced ranges are also possible (e.g., between
about 1
and about 100,000 ppm, between about 10 and about 10,000 ppm, between about
100
and about 5,000 ppm). Other ranges are also possible.
In some embodiments, the emulsion or microemulsion comprise between about 1
wt% and 95 wt% water, between about 1 wt% and 99 wt% solvent, between about 0
wt%
and about 50 wt% alcohol, between about 1 wt% and 90 wt% surfactant, and
between
about 0 wt% and about 70 wt% freezing point depression agent, and between
about 0
wt% and about 70 wt% other additives, versus the total microemulsion
composition. In
some embodiments, the emulsion or microemulsion comprise between about 1 wt%
and
60 wt% water, between about 1 wt% and 30 wt% solvent, between about 1 wt% and
about 50 wt% alcohol, between about 5 wt% and 65 wt% surfactant, and between
about
0 wt% and about 25 wt% freezing point depression agent, and between about 0
wt% and
about 30 wt% other additives, versus the total microemulsion composition. In
some
embodiments, for the formulation above, the water is present in an amount
between
about 10 wt% and about 55 wt%, or between about 15 wt% and about 45 wt%. In
some
embodiments, for the formulation above the solvent is present in an amount
between
about 2 wt% and about 25 wt%, or between about 5 wt% and about 25 wt%. In some
embodiments, the solvent comprises a terpene. In some embodiments, for the
formulations above, the alcohol is present in an amount between about 5 wt%
and about
40 wt%, or between about 5 wt% and 35 wt%. In some embodiments, the alcohol
comprises isopropanol. In some embodiments, for the formulations above, the
surfactant
is present in an amount between about 5 wt% and 60 wt%, or between about 10
wt% and
55 wt%. In some embodiments, for the formulations above, the freezing point
depression
agent is present in an amount between about 1 wt% and about 25 wt%, or between
about
1 wt% and about 20 wt%, or between about 3 wt% and about 20 wt%. In some
embodiments, for the formulations above, the other additives are present in an
amount
between about 1 wt% and about 30 wt%, or between about 1 wt% and about 25 wt%,
or
between about 1 wt% and about 20 wt%. In some embodiments, the other additives
comprise one or more salts and/or one or more acids.
In some embodiments, a microemulsion composition comprises between about 5
wt% to about 60 wt% water, from about 2 wt% to about 50 wt% solvent, from
about 5
wt% to about 60 wt% of a first type of a solubilizing surfactant, from about 2
wt% to
- 9 -
CA 02904728 2015-09-17
about 50 wt% of alcohol, from about 0.5 to 30 wt% of a freezing point
depression agent,
from about 0.5 wt% to about 30 wt% of a second type of surfactant, from about
0 wt% to
about 70 wt% of other additives (e.g., acid), and from about 0.5 wt% to about
30% of
mutual solvent, which is miscible together with the water and the solvent. In
some
embodiments, the solvent is a substance with a significant hydrophobic
character with
linear, branched, cyclic, bicyclic, saturated or unsaturated structure,
including but not
limited to terpenes, terpineols, terpene alcohols, aldehydes, ketones, esters,
amines, and
amides. Non-limiting examples of suitable mutual solvents include
ethyleneglycolmonobutyl ether (EGMBE), dipropylene glycol monomethyl ether,
short
chain alcohols (e.g., isopropanol), tetrahydrofuran, dioxane,
dimethylformamide, and
dimethylsulfoxide. Freezing point depressions agents are described in more
detail herein,
and include, but are not limited to, alkali metal or earth alkali metal salts,
preferably
chlorides, urea, and alcohols (e.g., glycols such as propylene glycol and
triethylene
glycol). In some embodiments, the solubilizing surfactant is a molecule
capable of
forming a colloidal solution of the said solvent in predominantly aqueous
media.
Generally, surfactants are amphiphilic molecules that adsorb at interfaces to
lower
surface energy and can be used to form microemulsions in which they stabilize
a mixture
of polar and non-polar solvent. Non-limiting examples of suitable surfactants
include
nonionic surfactants with linear or branched structure, including, but not
limited to,
ethoxylated fatty alcohols, ethoxylated castor oils, and alkyl glucosides with
a
hydrocarbon chain of at least 8 carbon atoms and mole % of ethoxylation of 5
or more.
Additional surfactants are described herein. Non-limiting examples of second
types of
surfactants include adsorption modifiers, foamers, surface tension lowering
enhancers,
and emulsion breaking additives. Specific examples of such surfactants include
cationic
surfactants with a medium chain length, linear or branched anionic
surfactants, amine
oxides, amphoteric surfactants, silicone based surfactants, alkoxylated
novolac resins
(e.g. alkoxylated phenolic resins), alkoxylated polyimines, alkoxylated
polyamines, and
fluorosurfactants.
In some embodiments, the emulsion or microemulsion is as described in U.S.
Patent Number 7,380,606 and entitled "Composition and Process for Well
Cleaning,"
herein incorporated by reference.
The microemulsion generally comprises a solvent. The solvent, or a combination
of solvents, may be present in the microemulsion in any suitable amount. In
some
- 10 -
CA 02904728 2015-09-17
embodiments, the total amount of solvent present in the microemulsion is
between about
1 wt% and about 99 wt%, or between about 2 wt% and about 90 wt %, or between
about
1 wt% and about 60 wt%, or between about 2 wt% and about 60 wt%, or between
about
1 and about 50 wt%, or between about 1 and about 30 wt%, or between about 5
wt% and
about 40 wt%, or between about 5 wt% and about 30 wt%, or between about 2 wt%
and
about 25 wt%, or between about 5 wt% and about 25 wt%, or between about 60 wt%
and
about 95 wt%, or between about 70 wt% or about 95 wt%, or between about 75 wt%
and
about 90 wt%, or between about 80 wt% and about 95 wt%, versus the total
microemulsion composition.
Those of ordinary skill in the art will appreciate that microemulsions
comprising
more than two types of solvents may be utilized in the methods, compositions,
and
systems described herein. For example, the microemulsion may comprise more
than one
or two types of solvent, for example, three, four, five, six, or more, types
of solvents. In
some embodiments, the microemulsion comprises a first type of solvent and a
second
type of solvent. The first type of solvent to the second type of solvent ratio
in a
microemulsion may be present in any suitable ratio. In some embodiments, the
ratio of
the first type of solvent to the second type of solvent by weight is between
about 4:1 and
1:4, or between 2:1 and 1:2, or about 1:1.
In some embodiments, the solvent is an unsubstituted cyclic or acyclic,
branched
or unbranched alkane having 6-12 carbon atoms. In some embodiments, the cyclic
or
acyclic, branched or unbranched alkane has 6-10 carbon atoms. Non-limiting
examples
of unsubstituted acyclic unbranched alkanes having 6-12 carbon atoms include
hexane,
heptane, octane, nonane, decane, undecane, and dodecane. Non-limiting examples
of
unsubstituted acyclic branched alkanes having 6-12 carbon atoms include
isomers of
methylpentane (e.g., 2-methylpentane, 3-methylpentane), isomers of
dimethylbutane
(e.g., 2,2-dimethylbutane, 2,3-dimethylbutane), isomers of methylhexane (e.g.,
2-
methylhexane, 3-methylhexane), isomers of ethylpentane (e.g., 3-ethylpentane),
isomers
of dimethylpentane (e.g., 2,2,-dimethylpentane, 2,3-dimethylpentane, 2,4-
dimethylpentane, 3,3-dimethylpentane), isomers of trimethylbutane (e.g., 2,2,3-
trimethylbutane), isomers of methylheptane (e.g., 2-methylheptane, 3-
methylheptane, 4-
methylheptane), isomers of dimethylhexane (e.g., 2,2-dimethylhexane, 2,3-
dimethylhexane, 2,4-dimethylhexane, 2,5-dimethylhexane, 3,3-dimethylhexane,
3,4-
dimethylhexane), isomers of ethylhexane (e.g., 3-ethylhexane), isomers of
- 11 -
CA 02904728 2015-09-17
trimethylpentane (e.g., 2,2,3-trimethylpentane, 2,2,4-trimethylpentane, 2,3,3-
trimethylpentane, 2,3,4-trimethylpentane), and isomers of ethylmethylpentane
(e.g., 3-
ethy1-2-methylpentane, 3-ethy1-3-methylpentane). Non-limiting examples of
unsubstituted cyclic branched or unbranched alkanes having 6-12 carbon atoms,
include
cyclohexane, methylcyclopentane, ethylcyclobutane, propylcyclopropane,
isopropylcyclopropane, dimethylcyclobutane, cycloheptane, methylcyclohexane,
dimethylcyclopentane, ethylcyclopentane, trimethylcyclobutane, cyclooctane,
methylcycloheptane, dimethylcyclohexane, ethylcyclohexane, cyclononane,
methylcyclooctane, dimethylcycloheptane, ethylcycloheptane,
trimethylcyclohexane,
ethylmethylcyclohexane, propylcyclohexane, and cyclodecane. In a particular
embodiment, the unsubstituted cyclic or acyclic, branched or unbranched alkane
having
6-12 carbon is selected from the group consisting of heptane, octane, nonane,
decane,
2,2,4-trimethylpentane (isooctane), and propylcyclohexane.
In some embodiments, the solvent is an unsubstituted acyclic branched or
unbranched alkene having one or two double bonds and 6-12 carbon atoms. In
some
embodiments, the solvent is an unsubstituted acyclic branched or unbranched
alkene
having one or two double bonds and 6-10 carbon atoms. Non-limiting examples of
unsubstituted acyclic unbranched alkenes having one or two double bonds and 6-
12
carbon atoms include isomers of hexene (e.g., 1-hexene, 2-hexene), isomers of
hexadiene
(e.g., 1,3-hexadiene, 1,4-hexadiene), isomers of heptene (e.g., 1-heptene, 2-
heptene, 3-
heptene), isomers of heptadiene (e.g., 1,5-heptadiene, 1-6, heptadiene),
isomers of octene
(e.g., 1-octene, 2-octene, 3-octene), isomers of octadiene (e.g., 1,7-
octadiene), isomers of
nonene, isomers of nonadiene, isomers of decene, isomers of decadiene, isomers
of
undecene, isomers of undecadiene, isomers of dodecene, and isomers of
dodecadiene. In
some embodiments, the acyclic unbranched alkene having one or two double bonds
and
6-12 carbon atoms is an alpha-olefin (e.g., 1-hexene, 1-heptene, 1-octene, 1-
nonene, 1-
decene, 1-undecene, 1-dodecene). Non-limiting examples unsubstituted acyclic
branched
alkenes include isomers of methylpentene, isomers of dimethylpentene, isomers
of
ethylpentene, isomers of methylethylpentene, isomers of propylpentene, isomers
of
methylhexene, isomers of ethylhexene, isomers of dimethylhexene, isomers of
methylethylhexene, isomers of methylheptene, isomers of ethylheptene, isomers
of
dimethylhexptene, and isomers of methylethylheptene. In a particular
embodiment, the
- 12 -
CA 02904728 2015-09-17
, .
unsubstituted acyclic unbranched alkene having one or two double bonds and 6-
12
carbon atoms is selected from the group consisting of 1-octene and 1,7-
octadiene.
In some embodiments, the solvent is a cyclic or acyclic, branched or
unbranched
alkane having 9-12 carbon atoms and substituted with only an ¨OH group. Non-
limiting
examples of cyclic or acyclic, branched or unbranched alkanes having 9-12
carbon atoms
and substituted with only an ¨OH group include isomers of nonanol, isomers of
decanol,
isomers of undecanol, and isomers of dodecanol. In a particular embodiment,
the cyclic
or acyclic, branched or unbranched alkane having 9-12 carbon atoms and
substituted
with only an ¨OH group is selected from the group consisting of 1-nonanol and
1-
1() decanol.
In some embodiments, the solvent is a branched or unbranched dialkylether
compound having the formula CriH2n-FIOCinH2m+1 wherein n + m is between 6 and
16. In
some cases, n + m is between 6 and 12, or between 6 and 10, or between 6 and
8. Non-
limiting examples of branched or unbranched dialkylether compounds having the
formula CnH2,i+10C.H2m+1 include isomers of C3H70C3H7, isomers of C4H90C3117,
isomers of C5H1 10C3H7, isomers of C6H130C3H7, isomers of C4H90C4H9, isomers
of
C4H90C5H11, isomers of C4H90061-113, isomers of CsHi 10061-113, and isomers of
C6F1130C6H13. In a particular embodiment, the branched or unbranched
dialklyether is an
isomer C6I-1130C6H13 (e.g., dihexylether).
In some embodiments, the solvent is an aromatic solvent having a boiling point
between about 300-400 F. Non-limiting examples of aromatic solvents having a
boiling
point between about 300-400 F include butylbenzene, hexylbenzene, mesitylene,
light
aromatic naphtha, and heavy aromatic naphtha.
In some embodiments, the solvent is a bicyclic hydrocarbon solvent with
varying
degrees of unsaturation including fused, bridgehead, and spirocyclic
compounds. Non-
limiting examples of bicyclic solvents include isomers of decalin,
tetrahydronapthalene,
norbornane, norbornene, bicyclo[4.2.0]octane, bicyclo[3.2.1]octane, and
spiro[5.5]dodecane.
In some embodiments, the solvent is a bicyclic hydrocarbon solvent with
varying
degrees of unsaturation and containing at least one 0, N, or S atom including
fused,
bridgehead, and spirocyclic compounds. Non-limiting examples include isomers
of 7
oxabicyclo[2.2.1]heptane, 4,7-epoxyisobenzofuran-1,3-dione, and 7
oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid, 2,3-dimethyl ester.
- 13 -
CA 02904728 2015-09-17
. .
In some embodiments, the solvent is a cyclic or acyclic, branched or
unbranched
alkane having 8 carbon atoms and substituted with only an ¨OH group. Non-
limiting
examples of cyclic or acyclic, branched or unbranched alkanes having 8 carbon
atoms
and substituted with only an ¨OH group include isomers of octanol (e.g., 1-
octanol, 2-
octanol, 3-octanol, 4-octanol), isomers of methyl heptanol, isomers of
ethylhexanol (e.g.,
2-ethyl-1 -hexanol, 3-ethyl-1 -hexanol, 4-ethyl-1 -hexanol), isomers of
dimethylhexanol,
isomers of propylpentanol, isomers of methylethylpentanol, and isomers of
trimethylpentanol. In a particular embodiment, the cyclic or acyclic, branched
or
unbranched alkane having 8 carbon atoms and substituted with only an ¨OH group
is
selected from the group consisting of 1-octanol and 2-ethyl-1-hexanol.
In some embodiments, the amine is of the formula NR1R2R3, wherein RI, R2, and
R3 are the same or different and are hydrogen or cyclic or acyclic, branched
or
unbranched alkyl (e.g., C1-16 alkyl), optionally substituted, or optionally,
any two of RI,
R2 and R3 are joined together to form a ring. In some embodiments, each of RI,
R2, and
R3 are the same or different and are hydrogen or cyclic or acyclic, branched
or
unbranched alkyl, or optionally, any two of RI, R2 and R3 are joined together
to form a
ring, provide at least one of RI, R2, and R3 is methyl or ethyl. In some
cases, RI is cyclic
or acyclic, branched or unbranched C1-C6 alkyl and R2 and R3 are the same or
different
and are hydrogen or cyclic or acyclic, branched or unbranched alkyl (e.g., C8-
16 alkyl), or
optionally, R2 and R3 may be joined together to form a ring. In some cases, RI
is methyl
or ethyl and R2 and R3 are the same or different and are hydrogen or cyclic or
acyclic,
branched or unbranched alkyl (e.g., C8-16 alkyl), or optionally, R2 and R3 may
be joined
together to form a ring. In some cases, RI is methyl and R2 and R3 are the
same or
different and are hydrogen or cyclic or acyclic, branched or unbranched alkyl
(e.g., C8-16
alkyl), or optionally, R2 and R3 may be joined together to form a ring. In
some cases, RI
and R2 are the same or different and are hydrogen or cyclic or acyclic,
branched or
unbranched C1-C6 alkyl and R3 is branched or unbranched alkyl (e.g., C8-16
alkyl). In
some cases, RI and R2 are the same or different and are methyl or ethyl and R3
is
hydrogen or cyclic or acyclic, branched or unbranched alkyl (e.g., C8-16
alkyl). In some
cases, RI and R2 are methyl and R3 is hydrogen or cyclic or acyclic, branched
or
unbranched alkyl (e.g., C8-16 alkyl).
In some embodiments, the amine is of the formula NRIR2R3, wherein RI, R2, and
R3 are the same or different and are cyclic or acyclic, branched or unbranched
alkyl (e.g.,
- 14 -
CA 02904728 2015-09-17
C1-16 alkyl), optionally substituted, or optionally, any two of R', R2 and R3
are joined
together to form a ring. In some embodiments, each of R1, R2, and R3 are the
same or
different and are cyclic or acyclic, branched or unbranched alkyl, or
optionally, any two
of R1, R2 and R3 are joined together to form a ring, provide at least one of
R1, R2, and R3
is methyl or ethyl. In some cases, R1 is cyclic or acyclic, branched or
unbranched C1-C6
alkyl and R2 and R3 are the same or different and are cyclic or acyclic,
branched or
unbranched alkyl (e.g., C8-16 alkyl), or optionally, R2 and R3 may be joined
together to
form a ring. In some cases, R1 is methyl or ethyl and R2 and R3 are the same
or different
and are cyclic or acyclic, branched or unbranched alkyl (e.g., C8_16 alkyl),
or optionally,
o R2 and R3 may be joined together to form a ring. In some cases, R1 is
methyl and R2 and
R3 are the same or different and are cyclic or acyclic, branched or unbranched
alkyl (e.g.,
C8_16 alkyl), or optionally, R2 and R3 may be joined together to form a ring.
In some
cases, R1 and R2 are the same or different and are cyclic or acyclic, branched
or
unbranched Ci-C6 alkyl and R3 is branched or unbranched alkyl (e.g., C8-16
alkyl). In
some cases, R1 and R2 are the same or different and are methyl or ethyl and R3
is cyclic
or acyclic, branched or unbranched alkyl (e.g., C8-16 alkyl). In some cases,
R1 and R2 are
methyl and R3 is cyclic or acyclic, branched or unbranched alkyl (e.g., C8-16
alkyl).
In some embodiments, the amine is of the formula NR1R2R3, wherein R1 is
methyl and R2 and R3 are the same or different and are hydrogen or cyclic or
acyclic,
branched or unbranched C8-16 alkyl, or optionally R2 and R3 are joined
together to form a
ring. Non-limiting examples of amines include isomers of N-methyl-octylamine,
isomers
of N-methyl-nonylamine, isomers of N-methyl-decylamine, isomers of N
methylundecylamine, isomers of N-methyldodecylamine, isomers of N methyl
teradecylamine, and isomers of N-methyl-hexadecylamine. In certain
embodiments, the
amine is selected from the group consisting of N methyldecylamine and N
methylhexadecylamine.
In some embodiments, the amine is of the formula NR1R2R3, wherein R1 is
methyl and R2 and R3 are the same or different and are cyclic or acyclic,
branched or
unbranched C8_16 alkyl, or optionally R2 and R3 are joined together to form a
ring. In
some embodiments, the amine is of the formula NR1R2R3, wherein R1 is methyl
and R2
and R3 are the same or different and are cyclic or acyclic, branched or
unbranched C8-16
alkyl, or optionally R2 and R3 are joined together to form a ring. Non-
limiting examples
of amines include isomers of N-methyl-N-octyloctylamine, isomers of N-methyl-N-
- 15-
CA 02904728 2015-09-17
nonylnonylamine, isomers of N-methyl-N-decyldecylamine, isomers of N-methyl-N-
undecylundecylamine, isomers of N-methyl-N-dodecyldodecylamine, isomers of N-
methyl-N-tetradecylteradecylamine, isomers of N-methyl-N-
hexadecylhdexadecylamine,
isomers of N-methyl-N-octylnonylamine, isomers of N-methyl-N-octyldecylamine,
isomers of N-methyl-N-octyldodecylamine, isomers of N-methyl-N-
octylundecylamine,
isomers of N-methyl-N-octyltetradecylamine, isomers of N-methyl-N-
octylhexadecylamine, N-methyl-N-nonyldecylamine, isomers of N-methyl-N-
nonyldodecylamine, isomers of N-methyl-N-nonyltetradecylamine, isomers of N-
methyl-N-nonylhexadecylamine, isomers of N-methyl-N-decyldodecylamine, isomers
of
N-methyl-N-decylundecylamine, isomers of N-methyl-N-decyldodecylamine, isomers
of
N-methyl-N-decyltetradecylamine, isomers of N-methyl-N-decylhexadecylamine,
isomers of N-methyl-N-dodecylundecylamine, isomers of N-methyl-N-
dodecyltetradecylamine, isomers of N-methyl-N-dodecylhexadecylamine, and
isomers of
N-methyl-N-tetradecylhexadecylamine. In certain embodiments, the amine is
selected
from the group consisting of N-methyl-N-octyloctylamine, isomers of N-methyl-N-
nonylnonylamine, isomers of N-methyl N-decyldecylamine, isomers of N-methyl-N-
undecylundecylamine, isomers of N-methyl-N-dodecyldodecylamine, isomers of N-
methyl-N-tetradecylteradecylamine, and isomers of N-methyl-N
hexadecylhdexadecylamine. In certain embodiments, the amine is selected from
the
group consisting of N-methyl-N-dodecyldodecylamine and isomers of N-methyl-N
hexadecylhexadecylamine. In certain embodiments, the amine is selected from
the group
consisting of isomers of N-methyl-N-octylnonylamine, isomers of N-methyl-N-
octyldecylamine, isomers of N-methyl-N-octyldodecylamine, isomers of N-methyl-
N-
octylundecylamine, isomers of N-methyl-N-octyltetradecylamine, isomers of N-
methyl-
N-octylhexadecylamine, N-methyl-N-nonyldecylamine, isomers of N-methyl-N-
nonyldodecylamine, isomers of N-methyl-N-nonyltetradecylamine, isomers of N-
methyl-N-nonylhexadecylamine, isomers of N-methyl-N-decyldodecylamine, isomers
of
N-methyl-N-decylundecylamine, isomers of N-methyl-N-decyldodecylamine, isomers
of
N-methyl-N-decyltetradecylamine, isomers of N-methyl-N-decylhexadecylamine,
isomers of N-methyl-N-dodecylundecylamine, isomers of N-methyl-N-
dodecyltetradecylamine, isomers of N-methyl-N-dodecylhexadecylamine, and
isomers of
N-methyl-N-tetradecylhexadecylamine. In certain embodiments, the cyclic or
acyclic,
branched or unbranched tri-substituted amines is selected from the group
consisting of
- 16 -
CA 02904728 2015-09-17
N-methyl-N-octyldodecylamine, N-methyl-N-octylhexadecylamine or N-methyl-N-
dodecylhexadecylamine.
In certain embodiments, the amine is of the formula NR1R2R3, wherein RI and R2
are methyl and R3 is cyclic or acyclic, branched or unbranched C8.16 alkyl.
Non-limiting
examples of amines include isomers of N,N-dimethylnonylamine, isomers of N,N-
dimethyldecylamine, isomers of N,N-dimethylundecylamine, isomers of N,N-
dimethyldodecylamine, isomers of N,N-dimethyltetradecylamine, and isomers of
N,N-
dimethylhexadecylamine. In certain embodiments, the amine is selected from the
group
consisting of N,N-dimethyldecylamine, isomers of N,N-dodecylamine, and isomers
of
N,N-dimethylhexadecylamine.
In some embodiments, the amide is of the formula N(C=0R4)R5R6, wherein R4,
R5, and R6 are the same or different and are hydrogen or cyclic or acyclic,
branched or
unbranched alkyl (e.g., C1-16 alkyl), optionally substituted, or optionally,
R5 and R6 are
joined together to form a ring. In some embodiments, each of R4, R5, and R6
are the same
or different and are hydrogen or cyclic or acyclic, branched or unbranched
alkyl (e.g., CI_
16 alkyl), optionally substituted, or optionally, R5 and R6 are joined
together to form a
ring, provided at least one of R4, R5, and R6 is methyl or ethyl. In some
cases, R4 is
hydrogen or cyclic or acyclic, branched or unbranched C1-C6 alkyl, optionally
substituted, and R5 and R6 are the same or different and are hydrogen or
cyclic or
acyclic, branched or unbranched alkyl (e.g., C8.16 alkyl), optionally
substituted, or
optionally, R5 and R6 may be joined together to form a ring. In some cases, R4
is
hydrogen, methyl, or ethyl and R5 and R6 are the same or different and are
hydrogen or
cyclic or acyclic, branched or unbranched alkyl (e.g., C8-16 alkyl),
optionally substituted,
or optionally, R5 and R6 may be joined together to form a ring. In some cases,
R4 is
hydrogen and R5 and R6 are the same or different and are cyclic or acyclic,
branched or
unbranched alkyl (e.g., C8_16 alkyl), optionally substituted, or optionally,
R5 and R6 may
be joined together to form a ring. In some cases, R4 and R5 are the same or
different and
are hydrogen or cyclic or acyclic, branched or unbranched Ci-C6 alkyl,
optionally
substituted, and R6 is cyclic or acyclic, branched or unbranched alkyl (e.g.,
C8-16 alkyl),
optionally substituted. In some cases, R4 and R5 are the same or different and
are
hydrogen, methyl, or ethyl and R6 is cyclic or acyclic, branched or unbranched
alkyl
(e.g., C8-16 alkyl), optionally substituted. In some cases, R4 and R5 are
hydrogen and R6 is
cyclic or acyclic, branched or unbranched alkyl (e.g., C8-16 alkyl),
optionally substituted.
- 17-
CA 02904728 2015-09-17
In some cases, R6 is hydrogen or cyclic or acyclic, branched or unbranched C1-
C6 alkyl,
optionally substituted, and R4 and R5 are the same or different and are
hydrogen or cyclic
or acyclic, branched or unbranched alkyl (e.g., C8-16 alkyl), optionally
substituted, or
optionally. In some cases, R6 is hydrogen, methyl, or ethyl and R4 and R5 are
the same or
different and are hydrogen or cyclic or acyclic, branched or unbranched alkyl
(e.g., C8-16
alkyl). In some cases, R6 is hydrogen and R4 and R5 are the same or different
and are
cyclic or acyclic, branched or unbranched alkyl (e.g., C8-16 alkyl),
optionally substituted.
In some cases, R5 and R6 are the same or different and are hydrogen or cyclic
or acyclic,
branched or unbranched C1-C6 alkyl, optionally substituted, and R4 is cyclic
or acyclic,
1() branched or unbranched alkyl (e.g., C8_16 alkyl), optionally
substituted. In some cases, R5
and R6 are the same or different and are hydrogen, methyl, or ethyl and R4 is
cyclic or
acyclic, branched or unbranched alkyl (e.g., C8-16 alkyl), optionally
substituted. In some
cases, R5 and R6 are hydrogen and R4 is cyclic or acyclic, branched or
unbranched alkyl
(e.g., C8-16 alkyl), optionally substituted.
In some embodiments, the amide is of the formula N(C=0R4)R5R6, wherein R4,
R5, and R6 are the same or different and are cyclic or acyclic, branched or
unbranched
alkyl (e.g., C1-16 alkyl), optionally substituted, or optionally, R5 and R6
are joined
together to form a ring. In some embodiments, each of R4, R5, and R6 are the
same or
different and are cyclic or acyclic, branched or unbranched alkyl (e.g., C1-16
alkyl),
optionally substituted, or optionally, R5 and R6 are joined together to form a
ring,
provided at least one of R4, R5, and R6 is methyl or ethyl. In some cases, R4
is cyclic or
acyclic, branched or unbranched Ci-C6 alkyl, optionally substituted, and R5
and R6 are
the same or different and are hydrogen or cyclic or acyclic, branched or
unbranched alkyl
(e.g., C8-16 alkyl), optionally substituted, or optionally, R5 and R6 may be
joined together
to form a ring. In some cases, R4 is methyl or ethyl and R5 and R6 are the
same or
different and are cyclic or acyclic, branched or unbranched alkyl (e.g., C8-16
alkyl),
optionally substituted, or optionally, R5 and R6 may be joined together to
form a ring. In
some cases, R4 is and R5 and R6 are the same or different and are cyclic or
acyclic,
branched or unbranched alkyl (e.g., C8_16 alkyl), optionally substituted, or
optionally, R5
and R6 may be joined together to form a ring. In some cases, R4 is methyl and
R5 and R6
are the same or different and are cyclic or acyclic, branched or unbranched
alkyl (e.g.,
C8-16 alkyl), optionally substituted, or optionally, R5 and R6 may be joined
together to
form a ring. In some cases, R4 and R5 are the same or different and are methyl
or ethyl
- 18-
CA 02904728 2015-09-17
and R6 is cyclic or acyclic, branched or unbranched alkyl (e.g., C8-16 alkyl),
optionally
substituted. In some cases, R4 and R5 are methyl and R6 is cyclic or acyclic,
branched or
unbranched alkyl (e.g., C8-16 alkyl), optionally substituted. In some cases,
R6 is cyclic or
acyclic, branched or unbranched C1-C6 alkyl, optionally substituted, and R4
and R5 are
the same or different and are hydrogen or cyclic or acyclic, branched or
unbranched alkyl
(e.g., C8-16 alkyl), optionally substituted, or optionally. In some cases, R6
is methyl or
ethyl and R4 and R5 are the same or different and are hydrogen or cyclic or
acyclic,
branched or unbranched alkyl (e.g., C8-16 alkyl). In some cases, R6 is methyl
and R4 and
R5 are the same or different and are cyclic or acyclic, branched or unbranched
alkyl (e.g.,
C8-16 alkyl), optionally substituted. In some cases, R5 and R6 are the same or
different
and are cyclic or acyclic, branched or unbranched Ci-C6 alkyl, optionally
substituted, and
R4 is cyclic or acyclic, branched or unbranched alkyl (e.g., C8-16 alkyl),
optionally
substituted. In some cases, R5 and R6 are the same or different and are methyl
or ethyl
and R4 is cyclic or acyclic, branched or unbranched alkyl (e.g., C8-16 alkyl),
optionally
substituted. In some cases, R5 and R6 are methyl and R6 is cyclic or acyclic,
branched or
unbranched alkyl (e.g., C8-16 alkyl), optionally substituted.
In some embodiments, the amide is of the formula N(C=0R4)R5R6, wherein each
of R4, R5, and R6 are the same or different and are cyclic or acyclic,
branched or
unbranched C4-16 alkyl, optionally substituted, or optionally, R5 and R6 are
joined
together to form a ring. In some embodiments, the amide is of the formula
N(C=0R4)R5R6, wherein each of R4, R5, and R6 are the same or different and are
cyclic
or acyclic, branched or unbranched C8-16 alkyl, optionally substituted, or
optionally, R5
and R6 are joined together to form a ring. In some embodiments, the amide is
of the
formula N(C=0R4)R5R6, wherein each of R4, R5, and R6 are the same or different
and are
selected from the group consisting of t-butyl and cyclic or acyclic, branched
or
unbranched C5.16 alkyl, optionally substituted, or optionally, R5 and R6 are
joined
together to form a ring. In some embodiments, R4, R5, and R6 are the same or
different
and are selected from the group consisting of t-butyl and cyclic or acyclic,
branched or
unbranched C8-16 alkyl, optionally substituted, or optionally, R5 and R6 are
joined
together to form a ring. Non-limiting examples amides include N,N-
dioctyloctamide,
N,N-dinonylnonamide, N,N-didecyldecamide, N,N-didodecyldodecamide, N,N-
diundecylundecamide, N,N-ditetradecyltetradecamide, N,N-
dihexadecylhexadecamide,
N,N-didecyloctamide, N,N-didodecyloctamide, N,N-dioctyldodecamide, N,N-
- 19-
CA 02904728 2015-09-17
didecyldodecamide, N,N-dioctylhexadecamide, N,N-didecylhexadecamide, and N,N-
didodecylhexadecamide. In certain embodiments, the amide is selected from the
group
consisting of N,N-dioctyldodecamide and N,N-didodecyloctamide
In some embodiments, the amide is of the formula N(C=0R4)R5R6, wherein R6 is
hydrogen or C1-C3 alkyl and R4 and R5 are the same or different and are cyclic
or
acyclic, branched or unbranched C4-16 alkyl, optionally substituted. In some
embodiments, R6 is selected from the group consisting of hydrogen, methyl,
ethyl,
propyl and isopropyl, and R4 and R5 are the same or different and are cyclic
or acyclic,
branched or unbranched C4.16 alkyl, optionally substituted. In certain
embodiments, R6 is
selected from the group consisting of hydrogen, methyl, ethyl, propyl and
isopropyl, and
R4 and R5 are the same or different and are cyclic or acyclic, branched or
unbranched C8-
16 alkyl, optionally substituted. In some cases, at least one of R4 and R5 is
substituted
with a hydroxy group. In some embodiments, R6 is selected from the group
consisting of
hydrogen, methyl, ethyl, propyl, and isopropyl, and R4 and R5 are the same or
different
and are selected from the group consisting of tert-butyl, cyclic or acyclic,
branched or
unbranched C5-16 alkyl, optionally substituted, and cyclic or acyclic,
branched or
unbranched C1-16 alkyl substituted with an ¨OH group.
In some embodiments, the amide is of the formula N(C=0R4)R5R6, wherein R6 is
Ci-C3 alkyl and R4 and R5 are the same or different and are cyclic or acyclic,
branched or
unbranched C4_16 alkyl, optionally substituted. In some embodiments, R6 is
selected from
the group consisting of methyl, ethyl, propyl and isopropyl, and R4 and R5 are
the same
or different and are cyclic or acyclic, branched or unbranched C4-16 alkyl,
optionally
substituted. In certain embodiments, R6 is selected from the group consisting
of methyl,
ethyl, propyl and isopropyl, and R4 and R5 are the same or different and are
cyclic or
acyclic, branched or unbranched C8-16 alkyl, optionally substituted. In some
cases, at
least one of R4 and R5 is substituted with a hydroxy group. In some
embodiments, R6 is
selected from the group consisting of methyl, ethyl, propyl, and isopropyl,
and R4 and R5
are the same or different and are selected from the group consisting of tert-
butyl, cyclic
or acyclic, branched or unbranched C5.16 alkyl, optionally substituted, and
cyclic or
acyclic, branched or unbranched C1-16 alkyl substituted with an ¨OH group.
Non-limiting examples of amides include N,N-di-tert-butylformamide, N,N-
dipentylformamide, N,N-dihexylformamide, N,N-diheptylformamide, N,N-
dioctylformamide, N,N-dinonylformamide, N,N-didecylformamide, N,N-
- 20 -
CA 02904728 2015-09-17
diundecylformamide, N,N-didodecylformamide, N,N-dihydroxymethylformamide, N,N-
di-tert-butylacetamide, N,N-dipentylacetamide, N,N-dihexylacetamide, N,N-
diheptylacetamide, N,N-dioctylacetamide, N,N-dinonylacetamide, N,N-
didecylacetamide, N,N-diundecylacetamide, N,N-didodecylacetamide, N,N-
dihydroxymethylacetamide, N,N-dimethylpropionamide, N,N-diethylpropionamide,
N,N-dipropylpropionamide, such as N,N-di-n-propylpropionamide or N,N-
diisopropylpropionamide, N,N-dibutylpropionamide, such as N,N-di-n-
butylpropionamide, N,N-di-sec-butylpropionamide, N,N-diisobutylpropionamide or
N,N-di-tert-butylpropionamide, N,N-dipentylpropionamide, N,N-
dihexylpropionamide,
N,N-diheptylpropionamide, N,N-dioctylpropionamide, N,N-dinonylpropionamide,
N,N-
didecylpropionamide, N,N-diundecylpropionamide, N,N-didodecylpropionamide, N,N-
dimethyl-n-butyramide, N,N-diethyl-n-butyramide, N,N-dipropyl-n-butyramide,
such as
N,N-di-n-propyl-n-butyramide or N,N-diisopropyl-n-butyramide, N,N-dibutyl-n-
butyramide, such as N,N-di-n-butyl-n-butyramide, N,N-di-sec-butyl-n-
butyramide, N,N-
diisobutyl-n-butyramide, N,N-di-tert-butyl-n-butyramide, N,N-dipentyl-n-
butyramide,
N,N-dihexyl-n-butyramide, N,N-diheptyl-n-butyramide, N,N-dioctyl-n-butyramide,
N,N-dinonyl-n-butyramide, N,N-didecyl-n-butyramide, N,N-diundecyl-n-
butyramide,
N,N-didodecyl-n-butyramide, N,N-dipentylisobutyramide, N,N-
dihexylisobutyramide,
N,N-diheptylisobutyramide, N,N-dioctylisobutyramide, N,N-dinonylisobutyramide,
N,N-didecylisobutyramide, N,N-diundecylisobutyramide, N,N-
didodecylisobutyramide,
N,N-pentylhexylformamide, N,N-pentylhexylacetamide, N,N-
pentylhexylpropionamide,
N,N-pentylhexyl-n-butyramide, N,N-pentylhexylisobutyramide, N,N-
methylethylpropionamide, N,N-methyl-n-propylpropionamide, N,N-
methylisopropylpropionamide, N,N-methyl-n-butylpropionamide, N,N-methylethyl-n-
butyramide, N,N-methyl-n-butyramide, N,N-methylisopropyl-n-butyramide, N,N-
methyl-n-butyl-n-butyramide, N,N-methylethylisobutyramide, N,N-methyl-n-
propylisobutyramide, N,N-methylisopropylisobutyramide, and N,N-methyl-n-
butylisobutyramide. In certain embodiments, the amide is selected from the
group
consisting of N,N-dioctyldodecacetamide, N,N-methyl-N-
octylhexadecdidodecylacetamide, and N-methyl-N-
ihexadecyldodecylhexadecacetamide.
In some embodiments, the amide is of the formula N(C=0R4)R5R6, wherein R6 is
hydrogen or methyl and R4 and R5 are the same or different and are cyclic or
acyclic,
branched or unbranched C8-i6 alkyl. Non-limiting amides include isomers of N
- 21 -
CA 02904728 2015-09-17
methyloctamide, isomers of N-methylnonamide, isomers of N-methyldecamide,
isomers
of N methylundecamide, isomers of N methyldodecamide, isomers of N
methylteradecamide, and isomers of N-methyl-hexadecamide. In certain
embodiments
the amides are slected from the group consisteing of N methyloctamide, N
methyldodecamide, and N methylhexadecamide.
In some embodiments, the amide is of the formula N(C=0R4)R5R6, wherein R6 is
methyl and R4 and R5 are the same or different and are cyclic or acyclic,
branched or
unbranched C8-16 alkyl. Non-limiting amides include isomers of N-methyl-N-
octyloctamide, isomers of N-methyl-N-nonylnonamide, isomers of N-methyl-N-
decyldecamide, isomers of N methyl-N undecylundecamide, isomers of N methyl-N-
dodecyldodecamide, isomers of N methyl N-tetradecylteradecamide, isomers of N-
methyl-N-hexadecylhdexadecamide, isomers of N-methyl-N-octylnonamide, isomers
of
N-methyl-N-octyldecamide, isomers of N-methyl-N-octyldodecamide, isomers of N-
methyl-N-octylundecamide, isomers of N-methyl-N-octyltetradecamide, isomers of
N-
methyl-N-octylhexadecamide, N-methyl-N-nonyldecamide, isomers of N-methyl-N-
nonyldodecamide, isomers of N-methyl-N-nonyltetradecamide, isomers of N-methyl-
N-
nonylhexadecamide, isomers of N-methyl-N-decyldodecamide, isomers of N methyl-
N-
decylundecamide, isomers of N-methyl-N-decyldodecamide, isomers of N-methyl-N-
decyltetradecamide, isomers of N-methyl-N-decylhexadecamide, isomers of N
methyl-
N-dodecylundecamide, isomers of N methyl-N-dodecyltetradecamide, isomers of N-
methyl-N-dodecylhexadecamide, and isomers of N methyl-N-
tetradecylhexadecamide.
In certain embodiments, the amide is selected from the group consisting of
isomers of N-
methyl-N-octyloctamide, isomers of N-methyl-N-nonylnonamide, isomers of N-
methyl-
N-decyldecamide, isomers of N methyl-N undecylundecamide, isomers of N methyl-
N-
dodecyldodecamide, isomers of N methyl N-tetradecylteradecamide, and isomers
of N-
methyl-N-hexadecylhdexadecamide. In certain embodiments, amide is selected
from the
group consisting of N-methyl-N-octyloctamide, N methyl-N-dodecyldodecamide,
and N-
methyl-N-hexadecylhexadecamide. In certain embodiments, the amide is selected
from
the group consisting of isomers of N-methyl-N-octylnonamide, isomers of N-
methyl-N-
octyldecamide, isomers of N-methyl-N-octyldodecamide, isomers of N-methyl-N-
octylundecamide, isomers of N-methyl-N-octyltetradecamide, isomers of N-methyl-
N-
octylhexadecamide, N-methyl-N-nonyldecamide, isomers of N-methyl-N-
nonyldodecamide, isomers of N-methyl-N-nonyltetradecamide, isomers of N-methyl-
N-
- 22 -
CA 02904728 2015-09-17
f ,
nonylhexadecamide, isomers of N-methyl-N-decyldodecamide, isomers of N methyl-
N-
decylundecamide, isomers of N-methyl-N-decyldodecamide, isomers of N-methyl-N-
decyltetradecamide, isomers of N-methyl-N-decylhexadecamide, isomers of N
methyl-
N-dodecylundecamide, isomers of N methyl-N-dodecyltetradecamide, isomers of N-
methyl-N-dodecylhexadecamide, and isomers of N methyl-N-
tetradecylhexadecamide.
In certain embodiments, the amide is selected from the group consisting of N-
methyl-N-
octyldodecamide, N-methyl-N-octylhexadecamide, and N-methyl-N-
dodecylhexadecamide.
In some embodiments, the amide is of the formula N(C=0R4)R5R6, wherein R5
and R6 are the same or different and are hydrogen or C1-C3 alkyl and R4 is
cyclic or
acyclic, branched or unbranched C4_16 alkyl, optionally substituted. In some
embodiments, R5 and R6 are the same or different and are selected from the
group
consisting of hydrogen, methyl, ethyl, propyl and isopropyl, and R4 is cyclic
or acyclic,
branched or unbranched C4-16 alkyl, optionally substituted. In certain
embodiments, R5
and R6 are the same or different and are selected from the group consisting of
hydrogen,
methyl, ethyl, propyl and isopropyl and R4 is cyclic or acyclic, branched or
unbranched
C8_16 alkyl, optionally substituted. In some cases, R4 is substituted with a
hydroxy group.
In some embodiments, R5 and R6 are the same or different and are selected from
the
group consisting of hydrogen, methyl, ethyl, propyl, and isopropyl, and R4 is
selected
from the group consisting of tert-butyl, cyclic or acyclic, branched or
unbranched C5-16
alkyl, optionally substituted, and cyclic or acyclic, branched or unbranched
C1-16 alkyl
substituted with an ¨OH group.
In some embodiments, the amide is of the formula N(C=0R4)R5R6, wherein R5
and R6 are the same or different and are C1-C3 alkyl and R4 is cyclic or
acyclic, branched
or unbranched C4-16 alkyl, optionally substituted. In some embodiments, R5 and
R6 are
the same or different and are selected from the group consisting of methyl,
ethyl, propyl
and isopropyl, and R4 is cyclic or acyclic, branched or unbranched C4.16
alkyl, optionally
substituted. In certain embodiments, R5 and R6 are the same or different and
are selected
from the group consisting of methyl, ethyl, propyl and isopropyl and R4 is
cyclic or
acyclic, branched or unbranched C8_16 alkyl, optionally substituted. In some
cases, R4 is
substituted with a hydroxy group. In some embodiments, R5 and R6 are the same
or
different and are selected from the group consisting of methyl, ethyl, propyl,
and
isopropyl, and R4 is selected from the group consisting of tert-butyl, cyclic
or acyclic,
- 23 -
CA 02904728 2015-09-17
branched or unbranched C5.16 alkyl, optionally substituted, and cyclic or
acyclic,
branched or unbranched C1-16 alkyl substituted with an ¨OH group.
In some embodiments, the amide is of the formula N(C=0R4)R5R6, wherein R5
and R6 are methyl and R4 is cyclic or acyclic, branched or unbranched C8.16
alkyl. Non-
limiting examples of amides include isomers of N,N-dimethyloctamide, isomers
of N,N-
dimethylnonamide, isomers of N,N-dimethyldecamide, isomers of N,N-
dimethylundecamide, isomers of N,N-dimethyldodecamide, isomers of N,N-
dimethyltetradecamide, and isomers of N,N-dimethylhexadecamide. In certain
embodiments, the cyclic or acyclic, branched or unbranched tri-substituted
amines is
selected from the group consisting of N,N-dimethyloctamide, N,N-dodecamide,
and
N,N-dimethylhexadecamide.
In some embodiments, the solvent is an aromatic solvent having a boiling point
between about 175-300 F. Non-limiting examples of aromatic liquid solvents
having a
boiling point between about 175-300 F include benzene, xylenes, and toluene.
In a
particular embodiment, the solvent is not xylene.
In some embodiments, at least one of the solvents present in the microemulsion
is
an ester of fatty acid, either naturally occurring or synthetic with the
formula
R70(C=0R8), wherein R7 and R8 are the same or different and are cyclic or
acyclic,
branched or unbranched alkyl (e.g., C1-16 alkyl), optionally substituted. In
some
embodiments, each of R7 and R8 are the same or different and are cyclic or
acyclic,
branched or unbranched alkyl, or optionally, provide at least one of R7 and R8
is methyl,
ethyl, propyl, or butyl. Non-limiting examples include isomers of methyl
octanoate,
methyl decanoate, methyl dodecanoate, methyl undecanoate, methyl
hexadecanoate,
ethyl octanoate, ethyl decanoate, ethyl dodecanoate, ethyl undecanoate, ethyl
hexadecanoate, propyl octanoate, propyl decanoate, propyl dodecanoate, propyl
undecanoate, propyl hexadecanoate, butyl octanoate, butyl decanoate, butyl
dodecanoate,
butyl undecanoate, and butyl hexadecanoate. In certain embodiments, the esters
are
selected from the group consisting of methyl dodecanoate, methyl
hexadecanoate, ethyl
dodecanoate, ethyl hexadecanoate, propyl dodecanoate, propyl hexadecanoate,
butyl
dodecanoate, and butyl hexadecanoate. Non-limiting examples include isomers of
octyl
octanoate, nonyl, nonanoate, decyl decanoate,undecyl undecanoate, dodecyl
decanoate,
hexadecyl hexadecanoate. In certain embodiments the esters are selected from
the group
consisting of octyl octonoate and decyl decanoate.
- 24 -
CA 02904728 2015-09-17
In some embodiments, at least one of the solvents present in the microemulsion
is
a terpene or a terpenoid. In some embodiments, the terpene or terpenoid
comprises a first
type of terpene or terpenoid and a second type of terpene or terpenoid.
Terpenes may be
generally classified as monoterpenes (e.g., having two isoprene units),
sesquiterpenes
(e.g., having 3 isoprene units), diterpenes, or the like. The term terpenoid
also includes
natural degradation products, such as ionones, and natural and synthetic
derivatives, e.g.,
terpene alcohols, aldehydes, ketones, acids, esters, epoxides, and
hydrogenation products
(e.g., see Ullmann's Encyclopedia of Industrial Chemistry, 2012, pages 29-45,
herein
incorporated by reference). It should be understood, that while much of the
description
herein focuses on terpenes, this is by no means limiting, and terpenoids may
be
employed where appropriate. In some cases, the terpene is a naturally
occurring terpene.
In some cases, the terpene is a non-naturally occurring terpene and/or a
chemically
modified terpene (e.g., saturated terpene, terpene amine, fluorinated terpene,
or silylated
terpene).
In some embodiments, the terpene is a monoterpene. Monoterpenes may be
further classified as acyclic, monocyclic, and bicyclic (e.g., with a total
number of
carbons in the range between 18-20), as well as whether the monoterpene
comprises one
or more oxygen atoms (e.g., alcohol groups, ester groups, carbonyl groups,
etc.). In some
embodiments, the terpene is an oxygenated terpene, for example, a terpene
comprising
an alcohol, an aldehyde, and/or a ketone group. In some embodiments, the
terpene
comprises an alcohol group. Non-limiting examples of terpenes comprising an
alcohol
group are linalool, geraniol, nopol, a-terpineol, and menthol. In some
embodiments, the
terpene comprises an ether-oxygen, for example, eucalyptol, or a carbonyl
oxygen, for
example, menthone. In some embodiments, the terpene does not comprise an
oxygen
atom, for example, d-limonene.
Non-limiting examples of terpenes include linalool, geraniol, nopol, a-
terpineol,
menthol, eucalyptol, menthone, d-limonene, terpinolene,13-occimene, y-
terpinene,
a-pinene, and citronellene. In a particular embodiment, the terpene is
selected from the
group consisting of a-terpeneol, a-pinene, nopol, and eucalyptol. In one
embodiment, the
terpene is nopol. In another embodiment, the terpene is eucalyptol. In some
embodiments, the terpene is not limonene (e.g., d-limonene). In some
embodiments, the
emulsion is free of limonene.
- 25 -
CA 02904728 2015-09-17
In some embodiments, the terpene is a non-naturally occurring terpene and/or a
chemically modified terpene (e.g., saturated terpene). In some cases, the
terpene is a
partially or fully saturated terpene (e.g., p-menthane, pinane). In some
cases, the terpene
is a non-naturally occurring terpene. Non-limiting examples of non-naturally
occurring
terpenes include, menthene, p-cymene, r-carvone, terpinenes (e.g., alpha-
terpinenes,
beta-terpinenes, gamma-terpinenes), dipentenes, terpinolenes, borneol, alpha-
terpinamine, and pine oils.
In some embodiments, the terpene is classified in terms of its phase inversion
temperature (PIT). The term phase inversion temperature is given its ordinary
meaning in
the art and refers to the temperature at which an oil in water microemulsion
inverts to a
water in oil microemulsion (or vice versa). Those of ordinary skill in the art
will be
aware of methods for determining the PIT for a microemulsion comprising a
terpene
(e.g., see Strey, Colloid & Polymer Science, 1994. 272(8): p. 1005-1019;
Kahlweit et al.,
Angewandte Chemie International Edition in English, 1985. 24(8): p. 654-668).
The PIT
values described herein were determined using a 1:1 ratio of terpene (e.g.,
one or more
terpenes):de-ionized water and varying amounts (e.g., between about 20 wt% and
about
60 wt%; generally, between 3 and 9 different amounts are employed) of a 1:1
blend of
surfactant comprising linear C12-C15 alcohol ethoxylates with on average 7
moles of
ethylene oxide (e.g., Neodol 25-7):isopropyl alcohol wherein the upper and
lower
temperature boundaries of the microemulsion region can be determined and a
phase
diagram may be generated. Those of ordinary skill in the art will recognize
that such a
phase diagram (e.g., a plot of temperature against surfactant concentration at
a constant
oil-to-water ratio) may be referred to as fish diagram or a Kahlweit plot. The
temperature
at the vertex is the PIT. An exemplary fish diagram indicating the PIT is
shown in Figure
1. PITs for non-limiting examples of terpenes determined using this
experimental
procedure outlined above are given in Table 1.
Table 1: Phase inversion temperatures for non-limiting examples of terpenes.
Terpene Phase Inversion Temperature F ( C)
linalool 24.8 (-4)
geraniol 31.1 (-0.5)
nopol 36.5 (2.5)
a-terpineol 40.3 (4.6)
- 26 -
CA 02904728 2015-09-17
menthol 60.8 (16)
eucalyptol 87.8 (31)
menthone 89.6 (32)
d-limonene 109.4 (43)
terpinolene 118.4 (48)
I3-occimene 120.2 (49)
y-terpinene 120.2 (49)
a-pinene 134.6 (57)
citronellene 136.4 (58)
In certain embodiments, the solvent utilized in the emulsion or microemulsion
herein may comprise one or more impurities. For example, in some embodiments,
a
solvent (e.g., a terpene) is extracted from a natural source (e.g., citrus,
pine), and may
comprise one or more impurities present from the extraction process. In some
embodiment, the solvent comprises a crude cut (e.g., uncut crude oil, for
example, made
by settling, separation, heating, etc.). In some embodiments, the solvent is a
crude oil
(e.g., naturally occurring crude oil, uncut crude oil, crude oil extracted
from the wellbore,
synthetic crude oil, crude citrus oil, crude pine oil, eucalyptus, etc.). In
some
embodiments, the solvent is a citrus extract (e.g., crude orange oil, orange
oil, etc.).
In some embodiments, at least one of the solvents comprised in the emulsion or
microemulsion comprising a mutual solvent which is miscible together with the
water
and the solvent. In some embodiments, the mutual solvent is present in an
amount
between about at 0.5 wt% to about 30% of mutual solvent. Non-limiting examples
of
suitable mutual solvents include ethyleneglycolmonobutyl ether (EGMBE),
dipropylene
glycol monomethyl ether, short chain alcohols (e.g., isopropanol),
tetrahydrofuran,
dioxane, dimethylformamide, and dimethylsulfoxide.
Generally, the microemulsion comprises an aqueous phase. Generally, the
aqueous phase comprises water. The water may be provided from any suitable
source
(e.g., sea water, fresh water, deionized water, reverse osmosis water, water
from field
production). The water may be present in any suitable amount. In some
embodiments,
the total amount of water present in the microemulsion is between about 1 wt%
about 95
wt%, or between about 1 wt% about 90 wt%, or between about 1 wt% and about
60 wt%, or between about 5 wt% and about 60 wt% or between about 10 and about
55
- 27 -
CA 02904728 2015-09-17
,
wt%, or between about 15 and about 45 wt%, versus the total microemulsion
composition.
The water to solvent ratio in a microemulsion may be varied. In some
embodiments, the ratio of water to solvent, along with other parameters of the
solvent
may be varied. In some embodiments, the ratio of water to solvent by weight is
between
about 15:1 and 1:10, or between 9:1 and 1:4, or between 3.2:1 and 1:4.
In some embodiments, the emulsion or microemulsion comprises a surfactant.
The microemulsion may comprise a single surfactant or a combination of two or
more
surfactants. For example, in some embodiments, the surfactant comprises a
first type of
surfactant and a second type of surfactant. The term surfactant, as used
herein, is given
its ordinary meaning in the art and refers to compounds having an amphiphilic
structure
which gives them a specific affinity for oil/water-type and water/oil-type
interfaces
which helps the compounds to reduce the free energy of these interfaces and to
stabilize
the dispersed phase of a microemulsion. The term surfactant encompasses
cationic
surfactants, anionic surfactants, amphoteric surfactants, nonionic
surfactants, zwitterionic
surfactants, and mixtures thereof. In some embodiments, the surfactant is a
nonionic
surfactant. Nonionic surfactants generally do not contain any charges.
Amphoteric
surfactants generally have both positive and negative charges, however, the
net charge of
the surfactant can be positive, negative, or neutral, depending on the pH of
the solution.
Anionic surfactants generally possess a net negative charge. Cationic
surfactants
generally possess a net positive charge. Zwitterionic surfactants are
generally not pH
dependent. A zwitterion is a neutral molecule with a positive and a negative
electrical
charge, though multiple positive and negative charges can be present.
Zwitterions are
distinct from dipole, at different locations within that molecule.
In some embodiments, the surfactant is an amphiphilic block copolymer
surfactant where one block is hydrophobic and one block is hydrophilic. In
some such
embodiments, The hydrophilic block of these copolymer surfactants can be
nonionic,
anionic, cationic, amphoteric, or zwitterionic.
The term surface energy, as used herein, is given its ordinary meaning in the
art
and refers to the extent of disruption of intermolecular bonds that occur when
the surface
is created (e.g., the energy excess associated with the surface as compared to
the bulk).
Generally, surface energy is also referred to as surface tension (e.g., for
liquid-gas
interfaces) or interfacial tension (e.g., for liquid-liquid interfaces). As
will be understood
- 28 -
CA 02904728 2015-09-17
. .
by those skilled in the art, surfactants generally orient themselves across
the interface to
minimize the extent of disruption of intermolecular bonds (i.e. lower the
surface energy).
Typically, a surfactant at an interface between polar and non-polar phases
orients itself at
the interface such that the difference in polarity is minimized.
Those of ordinary skill in the art will be aware of methods and techniques for
selecting surfactants for use in the microemulsions described herein. In some
cases, the
surfactant(s) are matched to and/or optimized for the particular oil or
solvent in use. In
some embodiments, the surfactant(s) are selected by mapping the phase behavior
of the
microemulsion and choosing the surfactant(s) that gives the desired range of
phase
behavior. In some cases, the stability of the microemulsion over a wide range
of
temperatures is targeted as the microemulsion may be subject to a wide range
of
temperatures due to the environmental conditions present at the subterranean
formation
and/or reservoir.
The surfactant may be present in the microemulsion in any suitable amount. In
some embodiments, the surfactant is present in an amount between about 0 wt%
and
about 99 wt%, or between about 1 wt% and about 90 wt%, or between about 0 wt%
and
about 60 wt%, or between about 1 wt% and about 60 wt%, or between about 5 wt%
and
about 60 wt%, or between about 10 wt% and about 60 wt%, or between about 5 wt%
and
about 65 wt%, or between about 5 wt% and about 55 wt%, or between about 10 wt%
and
about 55 wt%, or between about 2 wt% and about 50 wt%, or between about 0 wt%
and
about 40 wt%, or between about 15 wt% and about 55 wt%, or between about 20
wt%
and about 50 wt%, versus the total microemulsion composition.
Suitable surfactants for use with the compositions and methods described
herein
will be known in the art. In some embodiments, the surfactant is an alkyl
polyglycol
ether, for example, having 2-250 ethylene oxide (EO) (e.g., or 2-200, or 2-
150, or 2-100,
or 2-50, or 2-40) units and alkyl groups of 4-20 carbon atoms. In some
embodiments, the
surfactant is an alkylaryl polyglycol ether having 2-250 EO units (e.g., or 2-
200, or 2-
150, or 2-100, or 2-50, or 2-40) and 8-20 carbon atoms in the alkyl and aryl
groups. In
some embodiments, the surfactant is an ethylene oxide/propylene oxide (E0/P0)
block
copolymer surfactant having 2-250 EO or PO units (e.g., or 2-200, or 2-150, or
2-100, or
2-50, or 2-40). In some embodiments, the surfactant is a fatty acid polyglycol
ester
having 6-24 carbon atoms and 2-250 E0 units (e.g., or 2-200, or 2-150, or 2-
100, or 2-
50, or 2-40). In some embodiments, the surfactant is a polyglycol ether of
hydroxyl-
- 29 -
CA 02904728 2015-09-17
containing triglyeerides (e.g., castor oil). In some embodiments, the
surfactant is an
alkylpolyglycoside of the general formula R"--0--4, where R" denotes a linear
or
branched, saturated or unsaturated alkyl group having on average 8-24 carbon
atoms and
Zn denotes an oligoglycoside group having on average n=1-10 hexose or pentose
units or
mixtures thereof. In some embodiments, the surfactant is a fatty ester of
glycerol,
sorbitol, or pentaerythritol. In some embodiments, the surfactant is an amine
oxide (e.g.,
dodecyldimethylamine oxide). In some embodiments, the surfactant is an alkyl
sulfate,
for example having a chain length of 8-18 carbon atoms, alkyl ether sulfates
having
8-18 carbon atoms in the hydrophobic group and 1-40 ethylene oxide (E0) or
propylene
oxide (PO) units. In some embodiments, the surfactant is a sulfonate, for
example, an
alkyl sulfonate having 8-18 carbon atoms, an alkylaryl sulfonate having 8-18
carbon
atoms, an ester or half ester of sulfosuccinic acid with monohydric alcohols
or
alkylphenols having 4-15 carbon atoms, or a multisulfonate (e.g., comprising
two, three,
four, or more, sulfonate groups). In some cases, the alcohol or alkylphenol
can also be
ethoxylated with 1-250 E0 units (e.g., or 2-200, or 2-150, or 2-100, or 2-50,
or 2-40). In
some embodiments, the surfactant is an alkali metal salt or ammonium salt of a
carboxylic acid or poly(alkylene glycol) ether carboxylic acid having 8-20
carbon atoms
in the alkyl, aryl, alkaryl or aralkyl group and 1-250 E0 or PO units (e.g.,
or 2-200, or 2-
150, or 2-100, or 2-50, or 2-40). In some embodiments, the surfactant is a
partial
phosphoric ester or the corresponding alkali metal salt or ammonium salt,
e.g., an alkyl
and alkaryl phosphate having 8-20 carbon atoms in the organic group, an
alkylether
phosphate or alkarylether phosphate having 8-20 carbon atoms in the alkyl or
alkaryl
group and 1-250 E0 units (e.g., or 2-200, or 2-150, or 2-100, or 2-50, or 2-
40). In some
embodiments, the surfactant is a salt of primary, secondary, or tertiary fatty
amine
having 8-24 carbon atoms with acetic acid, sulfuric acid, hydrochloric acid,
and
phosphoric acid. In some embodiments, the surfactant is a quaternary alkyl-
and
alkylbenzylammonium salt, whose alkyl groups have 1-24 carbon atoms (e.g., a
halide,
sulfate, phosphate, acetate, or hydroxide salt). In some embodiments, the
surfactant is an
alkylpyridinium, an alkylimidazolinium, or an alkyloxazolinium salt whose
alkyl chain
has up to 18 carbons atoms (e.g., a halide, sulfate, phosphate, acetate, or
hydroxide salt).
In some embodiments, the surfactant is amphoteric or zwitterionic, including
sultaines
(e.g., cocamidopropyl hydroxysultaine), betaines (e.g., cocamidopropyl
betaine), or
phosphates (e.g., lecithin). Non-limiting examples of specific surfactants
include a linear
-30-
CA 02904728 2015-09-17
C12-C15 ethoxylated alcohols with 5-12 moles of EO, lauryl alcohol ethoxylate
with 4-8
moles of EO, nonyl phenol ethoxylate with 5-9 moles of EO, octyl phenol
ethoxylate
with 5-9 moles of EO, tridecyl alcohol ethoxylate with 5-9 moles of EO,
Pluronic
matrix of EO/PO copolymer surfactants, ethoxylated cocoamide with 4-8 moles of
EO,
ethoxylated coco fatty acid with 7-11 moles of EO, and cocoamidopropyl amine
oxide.
In some embodiments, the surfactant is a siloxane surfactant as described in
U.S.
Patent Application Serial No. 13/831,410, filed March 14, 2014, herein
incorporated by
reference.
In some embodiments, the surfactant is a Gemini surfactant. Gemini surfactants
generally have the structure of multiple amphiphilic molecules linked together
by one or
more covalent spacers. In some embodiments, the surfactant is an extended
surfactant,
wherein the extended surfactant has the structure where a non-ionic
hydrophilic spacer
(e.g. ethylene oxide or propylene oxide) connects an ionic hydrophilic group
(e.g.
carboxylate, sulfate, phosphate).
In some embodiments the surfactant is an alkoxylated polyimine with a relative
solubility number (RSN) in the range of 5-20. As will be known to those of
ordinary skill
in the art, RSN values are generally determined by titrating water into a
solution of
surfactant in 1,4dioxane. The RSN value is generally defined as the amount of
distilled
water necessary to be added to produce persistent turbidity. In some
embodiments the
surfactant is an alkoxylated novolac resin (also known as a phenolic resin)
with a relative
solubility number in the range of 5-20. In some embodiments the surfactant is
a block
copolymer surfactant with a total molecular weight greater than 5000 daltons.
The block
copolymer surfactant may have a hydrophobic block that is comprised of a
polymer
chain that is linear, branched, hyperbranched, dendritic or cyclic. Non-
limiting examples
of monomeric repeat units in the hydrophobic chains of block copolymer
surfactants are
isomers of acrylic, methacrylic, styrenic, isoprene, butadiene, acrylamide,
ethylene,
propylene and norbomene. The block copolymer surfactant may have a hydrophilic
block that is comprised of a polymer chain that is linear, branched, hyper
branched,
dendritic or cyclic. Non-limiting examples of monomeric repeat units in the
hydrophilic
chains of the block copolymer surfactants are isomers of acrylic acid, maleic
acid,
methacrylic acid, ethylene oxide, and acrylamine. Those skilled in the art
would
understand, based upon the teachings of this specification, that the polymers
and
copolymers described herein in the context of the water flooding fluid (e.g.,
a water
-31-
CA 02904728 2015-09-17
flooding fluid comprising a polymer (or copolymer) and an emulsion or
microemulsion),
are different than the copolymer surfactants used to form an emulsion and/or
microemulsion.
In some embodiments, the surfactant has a structure as in Formula I:
R8
R7 R8
R120
0 al
R11
(I),
wherein each of R7, R8, R9, R10, and R11 are the same or different and are
selected from
the group consisting of hydrogen, optionally substituted alkyl, and ¨CH=CHAr,
wherein
Ar is an aryl group, provided at least one of R7, R8, R9, R1 , and R11 is
¨CH=CHAr, R12
is hydrogen or alkyl, n is 1-100, and each m is independently 1 or 2. In some
embodiments, Ar is phenyl. In some embodiments, for a compound of Formula (I),
R12 is
hydrogen or C16 alkyl. In some embodiments, for a compound of Formula (I), R12
is H,
methyl, or ethyl. In some embodiments, for a compound of Formula (I), R12 is
H.
In some embodiments, the surfactant has a structure as in Formula II:
R8
R7 R8
06
X Y*).,0 Rlo
\ m
R11
(II)
wherein each of R7, R8, R9, R1 , and R11 are the same or different and are
selected from
the group consisting of hydrogen, optionally substituted alkyl, and ¨CH=CHAr,
wherein
Ar is an aryl group, provided at least one of R7, R8, R9, R10, and R11 is
¨CH=CHAr, Y- is
an anionic group, X+ is a cationic group, n is 1-100, and each m is
independently 1 or 2.
In some embodiments, Ar is phenyl. In some embodiments, for a compound of
Formula
(II), X is a metal cation or N(R13)4, wherein each R13 is independently
selected from the
group consisting of hydrogen, optionally substituted alkyl, or optionally
substituted aryl.
- 32 -
CA 02904728 2015-09-17
In some embodiments, X+ is NH4. Non-limiting examples of metal cations are Na,
K+,
Mg'-2, and Ca+2. In some embodiments, for a compound of Formula (II), Y- is -
0", -
S020-, or -0S020-.
In some embodiments, the surfactant has a structure as in Formula III:
R8
R7 R9
z
0 Ri0
R11
(III)
wherein each of R7, R8, R9, R19, and R11 are the same or different and are
selected from
the group consisting of hydrogen, optionally substituted alkyl, and -CH=CHAr,
wherein
Ar is an aryl group, provided at least one of R7, R8, R9, R10, and R11 is -
CH=CHAr, Z+ is
a cationic group, n is 1-100, and each m is independently 1 or 2. In some
embodiments,
Ar is phenyl. In some embodiments, for a compound of Formula (III), Z+ is
N(R13)3,
wherein each R13 is independent selected from the group consisting of
hydrogen,
optionally substituted alkyl, or optionally substituted aryl.
In some embodiments, for a compound of Formula (I), (II), or (III), two of R7,
R8,
R9, R19, and R11 are -CH=CHAr. In some embodiments, for a compound of Formula
(I),
(II), or (III), one of R7, R8, R9, R19, and R" is -CH=CHAr and each of the
other groups is
hydrogen. In some embodiments, for a compound of Formula (I), (II), or (III),
two of R7,
R8, R9, R1 , and R" are -CH=CHAr and each of the other groups is hydrogen. In
some
embodiments, for a compound of Formula (I), (II), or (III), R7 and R8 are -
CH=CHAr
and R9, R10, and R11 are each hydrogen. In some embodiments, for a compound of
Formula (I), (II), or (III), three of R7, R8, R9, R19, and R11 are -CH=CHAr
and each of
the other groups is hydrogen. In some embodiments, for a compound of Formula
(I), (II),
or (III), R7, R8, and R9 are -CH=CHAr and R19 and R11 are each hydrogen. In
embodiments, for a compound of Formula (I), (II), or (III), Ar is phenyl. In
some
embodiments, for a compound of Formula (I), (II), or (III), each m is 1. In
some
embodiments, for a compound of Formula (I), (II), or (III), each m is 2. In
some
embodiments, for a compound of Formula (I), (II), or (III), n is 6-100, or 1-
50, or 6-50,
or 6-25, or 1-25, or 5-50, or 5-25, or 5-20.
-33-
CA 02904728 2015-09-17
In some embodiments, an emulsion or microemulsion comprises a surfactant of
Formula (I), (II), or (III) in an amount between about 1 wt% and about 20 wt%,
or
between about 3 wt% and about 15 wt%, or between about 5 wt% and about 13 wt%,
or
between about 5 wt% and about 11 wt%, or between about 7 wt% and about 11 wt%,
or
between about 10 wt% and about 12 wt%, or between about 8 wt% and about 12
wt%, or
between about 8 wt% and about 10 wt%, or about 9 wt%. In some embodiments, the
emulsion or microemulsion comprises, in addition to the surfactant of Formula
(I), (II),
or (III), water and a non-aqueous phase (e.g., a terpene), and optionally
other additives
(e.g., one or more additional surfactants, an alcohol, a freezing point
depression agent,
etc.). In some embodiments, the emulsion or microemulsion comprises, in
addition to the
surfactant of Formula (I), (II), or (III), water, a terpene, an alcohol, one
or more
additional surfactants, and optionally other additives (e.g., a freezing point
depression
agent). In some embodiments, the emulsion or microemulsion comprises, in
addition to
the surfactant of Formula (I), (II), or (III), between about 20 wt% and 90 wt%
water,
between about 2 wt% and about 70 wt% of one or more additional surfactants,
between
about 1 wt% and about 80 wt% of a solvent (e.g., terpene), and between about
10 wt%
and about 40 wt% of a mutual solvent (e.g., alcohol). In some embodiments, the
emulsion or microemulsion comprises, in addition to the surfactant of Formula
(I), (II),
or (III), between about 10 wt% and 80 wt% water, between about 2 wt% and about
80
wt% of one or more additional surfactants, between about 1 wt% and about 70
wt% of a
solvent (e.g., terpene), and between about 5 wt% and about 40 wt% of a mutual
solvent
(e.g., alcohol). In some embodiments, the emulsion or microemulsion comprises,
in
addition to the surfactant of Formula (I), (II), or (III), between about 20
wt% and 90 wt%
water, between about 2 wt% and about 70 wt% of one or more additional
surfactants,
between about 1 wt% and about 78 wt% of a solvent (e.g., terpene), and between
about
22 wt% and about 40 wt% of a mutual solvent (e.g., alcohol). Non-limiting
examples of
surfactants of Formula (I), (II), or (III) include styrylphenol ethoxylate, a
tristyrylphenol
ethoxylate, a styrylphenol propoxylate, a tristyrylphenol propoxylate, a
styrylphenol
ethoxylate propoxylate, or a tristyrylphenol ethoxylate propoxylate.
In some embodiments, the emulsion or microemulsion may comprise one or more
additives in addition to water, solvent (e.g., one or more types of solvents),
and
surfactant (e.g., one or more types of surfactants). In some embodiments, the
additive is
an alcohol, a freezing point depression agent, an acid, a salt, a proppant, a
scale inhibitor,
- 34 -
CA 02904728 2015-09-17
a friction reducer, a biocide, a corrosion inhibitor, a buffer, a viscosifier,
a clay swelling
inhibitor, an oxygen scavenger, and/or a clay stabilizer.
In some embodiments, the microemulsion comprises an alcohol. The alcohol may
serve as a coupling agent between the solvent and the surfactant and aid in
the
stabilization of the microemulsion. The alcohol may also lower the freezing
point of the
microemulsion. The microemulsion may comprise a single alcohol or a
combination of
two or more alcohols. In some embodiments, the alcohol is selected from
primary,
secondary and tertiary alcohols having between 1 and 20 carbon atoms. In some
embodiments, the alcohol comprises a first type of alcohol and a second type
of alcohol.
Non-limiting examples of alcohols include methanol, ethanol, isopropanol, n-
propanol,
n-butanol, i-butanol, sec-butanol, iso-butanol, and t-butanol. In some
embodiments, the
alcohol is ethanol or isopropanol. In some embodiments, the alcohol is
isopropanol.
The alcohol may be present in the emulsion in any suitable amount. In some
embodiments, the alcohol is present in an amount between about 0 wt% and about
50
wt%, or between about 0.1 wt% and about 50 wt%, or between about 1 wt% and
about
50 wt%, or between about 2 wt% and about 50 wt% or between about 5 wt% and
about
40 wt%, or between about 5 wt% and 35 wt%, versus the total microemulsion
composition.
In some embodiments, the microemulsion comprises a freezing point depression
agent. The microemulsion may comprise a single freezing point depression agent
or a
combination of two or more freezing point depression agents. For example, in
some
embodiments, the freezing point depression agent comprises a first type of
freezing point
depression agent and a second type of freezing point depression agent. The
term freezing
point depression agent is given its ordinary meaning in the art and refers to
a compound
which is added to a solution to reduce the freezing point of the solution.
That is, a
solution comprising the freezing point depression agent has a lower freezing
point as
compared to an essentially identical solution not comprising the freezing
point
depression agent. Those of ordinary skill in the art will be aware of suitable
freezing
point depression agents for use in the microemulsions described herein. Non-
limiting
examples of freezing point depression agents include primary, secondary, and
tertiary
alcohols with between 1 and 20 carbon atoms. In some embodiments, the alcohol
comprises at least 2 carbon atoms, alkylene glycols including polyalkylene
glycols, and
salts. Non-limiting examples of alcohols include methanol, ethanol, i-
propanol,
- 35 -
CA 02904728 2015-09-17
, .
n-propanol, t-butanol, n-butanol, n-pentanol, n-hexanol, and 2-ethyl-hexanol.
In some
embodiments, the freezing point depression agent is not methanol (e.g., due to
toxicity).
Non-limiting examples of alkylene glycols include ethylene glycol (EG),
polyethylene
glycol (PEG), propylene glycol (PG), and triethylene glycol (TEG). In some
5 embodiments, the freezing point depression agent is not ethylene oxide
(e.g., due to
toxicity). In some embodiments, the freezing point depression agent comprises
an
alcohol and an alkylene glycol. In some embodiments, the freezing point
depression
agent comprises a carboxycyclic acid salt and/or a di-carboxycylic acid salt.
Another
non-limiting example of a freezing point depression agent is a combination of
choline
10 chloride and urea. In some embodiments, the microemulsion comprising the
freezing
point depression agent is stable over a wide range of temperatures, for
example, between
about -50 F to 200 F.
The freezing point depression agent may be present in the microemulsion in any
suitable amount. In some embodiments, the freezing point depression agent is
present in
15 an amount between about 0 wt% and about 70 wt%, or between about 0.5 and
30 wt%,
or between about 1 wt% and about 40 wt%, or between about 0 wt% and about 25
wt%,
or between about 1 wt% and about 25 wt%, or between about 1 wt% and about 20
wt%,
or between about 3 wt% and about 20 wt%, or between about 8 wt% and about 16
wt%,
versus the total microemulsion composition.
20 In addition to the alcohol and the freezing point depression agent, the
microemulsion may comprise other additives. For example, the microemulsion may
comprise an acid and/or a salt. Further non-limiting examples of other
additives include
proppants, scale inhibitors, friction reducers, biocides, corrosion
inhibitors, buffers,
viscosifiers, clay swelling inhibitors, paraffin dispersing additives,
asphaltene dispersing
25 additives, and oxygen scavengers.
Non-limiting examples of proppants (e.g., propping agents) include grains of
sand, glass beads, crystalline silica (e.g., Quartz), hexamethylenetetramine,
ceramic
proppants (e.g., calcined clays), resin coated sands, and resin coated ceramic
proppants.
Other proppants are also possible and will be known to those skilled in the
art.
30 Non-limiting examples of scale inhibitors include one or more of methyl
alcohol,
organic phosphonic acid salts (e.g., phosphonate salt), polyacrylate, ethane-
1,2-diol,
calcium chloride, and sodium hydroxide. Other scale inhibitors are also
possible and will
be known to those skilled in the art.
- 36 -
CA 02904728 2015-09-17
Non-limiting examples of buffers include acetic acid, acetic anhydride,
potassium
hydroxide, sodium hydroxide, and sodium acetate. Other buffers are also
possible and
will be known to those skilled in the art.
Non-limiting examples of corrosion inhibitors include isopropanol, quaternary
ammonium compounds, thiourea/formaldehyde copolymers, propargyl alcohol and
methanol. Other corrosion inhibitors are also possible and will be known to
those skilled
in the art.
Non-limiting examples of biocides include didecyl dimethyl ammonium chloride,
gluteral, Dazomet, bronopol, tributyl tetradecyl phosphonium chloride,
tetrakis
(hydroxymethyl) phosphonium sulfate, AQUCARTM, UCARCIDETM, glutaraldehyde,
sodium hypochlorite, and sodium hydroxide. Other biocides are also possible
and will be
known to those skilled in the art.
Non-limiting examples of clay swelling inhibitors include quaternary ammonium
chloride and tetramethylammonium chloride. Other clay swelling inhibitors are
also
possible and will be known to those skilled in the art.
Non-limiting examples of friction reducers include petroleum distillates,
ammonium salts, polyethoxylated alcohol surfactants, and anionic
polyacrylamide
copolymers. Other friction reducers are also possible and will be known to
those skilled
in the art.
Non-limiting examples of oxygen scavengers include sulfites, and bisulfites.
Other oxygen scavengers are also possible and will be known to those skilled
in the art.
Non-limiting examples of paraffin dispersing additives and asphaltene
dispersing
additives include active acidic copolymers, active alkylated polyester, active
alkylated
polyester amides, active alkylated polyester imides, aromatic naphthas, and
active amine
sulfonates. Other paraffin dispersing additives are also possible and will be
known to
those skilled in the art.
In some embodiments, for the formulations above, the other additives are
present
in an amount between about 0 wt% about 70 wt%, or between about 0 wt % and
about 30
wt%, or between about 1 wt% and about 30 wt%, or between about I wt% and about
25
wt%, or between about 1 and about 20 wt%, versus the total microemulsion
composition.
In some embodiments, the microemulsion comprises an acid or an acid precursor.
For example, the microemulsion may comprise an acid when used during acidizing
operations. The microemulsion may comprise a single acid or a combination of
two or
-37-
CA 02904728 2015-09-17
more acids. For example, in some embodiments, the acid comprises a first type
of acid
and a second type of acid. Non-limiting examples of acids or di-acids include
hydrochloric acid, acetic acid, formic acid, succinic acid, maleic acid, malic
acid, lactic
acid, and hydrochloric-hydrofluoric acids. In some embodiments, the
microemulsion
comprises an organic acid or organic di-acid in the ester (or di-ester) form,
whereby the
ester (or diester) is hydrolyzed in the wellbore and/or reservoir to form the
parent organic
acid and an alcohol in the wellbore and/or reservoir. Non-limiting examples of
esters or
di-esters include isomers of methyl formate, ethyl formate, ethylene glycol
diformate,
a,a-4-trimethy1-3-cyclohexene-1-methylformate, methyl lactate, ethyl lactate,
a,a-4-
trimethyl 3-cyclohexene-1-methyllactate, ethylene glycol dilactate, ethylene
glycol
diacetate, methyl acetate, ethyl acetate, a,a,-4-trimethy1-3-cyclohexene-1-
methylacetate,
dimethyl succinate, dimethyl maleate, di(a,a-4-trimethy1-3-cyclohexene-1-
methyl)succinate, 1-methy1-4-(1-methyletheny1)-cyclohexylformate, 1-methy1-4-
(1-
ethylethenyl)cyclohexylactate, 1-methy1-4-(1-methylethenyl)cyclohexylacetate,
di(1-
methy-4-(1-methylethenyl)cyclohexyl)succinate.
In some embodiments, the microemulsion comprises a salt. The presence of the
salt may reduce the amount of water needed as a carrier fluid, and in
addition, may lower
the freezing point of the microemulsion. The microemulsion may comprise a
single salt
or a combination of two or more salts. For example, in some embodiments, the
salt
comprises a first type of salt and a second type of salt. Non-limiting
examples of salts
include salts comprising K, Na, Br, Cr, Cs, or Li, for example, halides of
these metals,
including NaC1, KC1, CaC12, and MgCl2.
In some embodiments, the microemulsion comprises a clay stabilizer. The
microemulsion may comprise a single clay stabilizer or a combination of two or
more
clay stabilizers. For example, in some embodiments, the salt comprises a first
type of
clay stabilizer and a second type of clay stabilizer. Non-limiting examples of
clay
stabilizers include salts above, polymers (PAC, PHPA, etc), glycols,
sulfonated asphalt,
lignite, sodium silicate, and choline chloride.
In some embodiments, the components of the microemulsion and/or the amounts
of the components are selected such that the microemulsion is stable over a
wide-range
of temperatures. For example, the microemulsion may exhibit stability between
about
-40 F and about 400 F, or between about -40 F and about 300 F or between
about
-40 F and about 150 F. Those of ordinary skill in the art will be aware of
methods and
- 38 -
CA 02904728 2015-09-17
techniques for determining the range of stability of the microemulsion. For
example, the
lower boundary may be determined by the freezing point and the upper boundary
may be
determined by the cloud point and/or using spectroscopy methods. Stability
over a wide
range of temperatures may be important in embodiments where the microemulsions
are
being employed in applications comprising environments wherein the temperature
may
vary significantly, or may have extreme highs (e.g., desert) or lows (e.g.,
artic).
The microemulsions described herein may be formed using methods known to
those of ordinary skill in the art. In some embodiments, the aqueous and non-
aqueous
phases may be combined (e.g., the water and the solvent(s)), followed by
addition of a
lo surfactant(s) and optionally (e.g., freezing point depression agent(s))
and agitation. The
strength, type, and length of the agitation may be varied as known in the art
depending
on various factors including the components of the microemulsion, the quantity
of the
microemulsion, and the resulting type of microemulsion formed. For example,
for small
samples, a few seconds of gentle mixing can yield a microemulsion, whereas for
larger
samples, longer agitation times and/or stronger agitation may be required.
Agitation may
be provided by any suitable source, for example, a vortex mixer, a stirrer
(e.g., magnetic
stirrer), etc.
Any suitable method for injecting the microemulsion (e.g., a diluted
microemulsion) into a wellbore may be employed. For example, in some
embodiments,
the microemulsion, optionally diluted, may be injected into a subterranean
formation by
injecting it into a well or wellbore in the zone of interest of the formation
and thereafter
pressurizing it into the formation for the selected distance. Methods for
achieving the
placement of a selected quantity of a mixture in a subterranean formation are
known in
the art. The well may be treated with the microemulsion for a suitable period
of time.
The microemulsion and/or other fluids may be removed from the well using known
techniques, including producing the well.
It should be understood, that in embodiments where a microemulsion is said to
be
injected into a wellbore, that the microemulsion may be diluted and/or
combined with
other liquid component(s) prior to and/or during injection (e.g., via straight
tubing, via
coiled tubing, etc.). For example, in some embodiments, the microemulsion is
diluted
with an aqueous carrier fluid (e.g., water, brine, sea water, fresh water, or
a well-
treatment fluid (e.g., an acid, a fracturing fluid comprising polymers,
produced water,
sand, slickwater, etc.,)) prior to and/or during injection into the wellbore.
In some
-39-
CA 02904728 2015-09-17
embodiments, a composition for injecting into a wellbore is provided
comprising a
microemulsion as described herein and an aqueous carrier fluid, wherein the
microemulsion is present in an amount between about 0.1 and about 50 gallons
per
thousand gallons (gpt) per dilution fluid, or between 0.1 and about 100 gpt,
or between
about 0.5 and about 10 gpt, or between about 0.5 and about 2 gpt.
The compositions and methods described herein may be used in various aspects
of the life cycle of an oil and/or gas well, including, but not limited to,
drilling, mud
displacement, casing, cementing, perforating, stimulation, enhanced oil
recovery/
improved oil recovery, etc.). Inclusion of an emulsion or microemulsion into
the fluids
typically employed in these processes, for example, drilling fluids, mud
displacement
fluids, casing fluids, cementing fluids, perforating fluid, stimulation
fluids, kill fluids,
etc., results in many advantages as compared to use of the fluid alone. For
example, in
some embodiments, the compositions and methods described herein may be used in
enhanced oil recovery and/or improved oil recovery operations.
In some embodiments, the water flooding fluid comprising a polymer and an
emulsion or microemulsion is injected into an oil and/or gas well comprising a
well bore.
In some embodiments, the solvent and/or surfactant may be added to a fluid
comprising
the polymer (e.g., water and the polymer) to form the emulsion or
microemulsion in a
water flooding fluid prior to injection into the wellbore. In certain
embodiments, the
polymer is diluted in a fluid comprising the emulsion or microemulsion prior
to injection
into the wellbore.
As will be known to those skilled in the art, generally during the life cycle
of the
well, procedures may be performed to increase the amount of oil and/or gas
recovered
from the wellbore. Such procedures are generally referred to as enhanced oil
recovery
(EOR) and/or improved oil recovery (IOR). EOR/IOR typically uses a secondary
or a
tertiary system (e.g., comprising one or more of water, polymers, surfactants,
etc.) to
create a new mechanism which increases the displacement of oil and/or gas from
the
reservoir for recovery. Generally, EOR/IOR uses an existing wellbore which has
been
converted into a recovering well (e.g., an injecting well). In some
embodiments, the
recovering well is used to inject the secondary or tertiary system into the
reservoir at a
continuous or noncontinuous rate and/or pressure to increase the amount of
hydrocarbons
extracted from the reservoir. Non-limiting examples of EOR/IOR procedures
include
water flooding, gas flooding, polymer flooding, and/or the use of surfactant
polymers.
- 40 -
CA 02904728 2015-09-17
For example, the EOR/IOR procedure may comprise an EOR/IOR fluid (e.g., a
water
flooding fluid, a polymer flooding fluid, a surfactant flooding fluid, a gas
flooding fluid,
a surfactant, or combinations thereof).
Generally, water flooding (e.g., secondary recovery) refers to the injection
of a
water flooding fluid into a reservoir to increase the amount of oil and/or gas
recovered
from the wellbore. In some embodiments, the water flooding fluid comprises one
or
more of water (e.g., water, makeup water, etc.), acidizing fluids (e.g.,
matrix acidizing
fluids), surfactants, polymers, and foam. In certain embodiments, the water
flooding
fluid comprises a polymer (e.g., a polymer flooding fluid), and/or a
surfactant (i.e. during
a surfactant flood), and/or a surfactant polymer flood (i.e. during a SP-
flood), and/or an
alkaline surfactant polymer (i.e. during an ASP-flood). In some embodiments,
the water
flooding fluid comprises an emulsion or microemulsion and a polymer. The
addition of
an emulsion or microemulsion to the water flooding fluid (e.g., comprising a
polymer)
may have many advantages as compared to a water flooding fluid alone including
increasing the adhesion of the polymer to oil, increasing interfacial
efficiency of the
polymer, increasing the amount of oil and/or gas extracted from the reservoir,
decreasing
the volume of water needed to extract the same amount of oil, and/or lowering
the
pressure necessary to extract hydrocarbons from the reservoir. In some
embodiments, the
addition of an emulsion or microemulsion to the water flooding fluid increases
the
recovery of fracturing fluids (e.g., fracturing fluids not previously
removed).
Generally, polymer gels are injected into the formation during secondary and
tertiary recovery to block water and gas (carbon dioxide and nitrogen) flow
from
previously swept zones and large fractures (e.g., thief zones) or to prevent
imbibition of
water from a part of the formation that abuts the oil containing zone. Use of
polymers in
these cases is commonly referred to as conformance control or water shut-off.
In some
embodiments, emulsions and microemulsions are injected into the formation as a
preflush to prepare the formation for the polymer gel injection. The addition
of an
emulsion or microemulsion prior to the injection of a polymer gel may have
many
advantages as compared the injection of a polymer gel alone including
enhancing the
adhesion of the polymer to the formation (e.g., by removing surface
contamination and
residual oil).
In certain embodiments, the water flooding fluid comprising a polymer and an
emulsion or microemulsion may have a particular viscosity. In some embodiments
the
- 41 -
CA 02904728 2015-09-17
viscosity of the flooding fluid with polymer and emulsions and/or
microemulsions
between about 1 cP and about 1,000 cP, or between about 1 cP and about 500 cP,
or
between about 1 cP and about 100 cP, or between about 10 cP and about 200 cP,
or
between about 70 cP and about 200 cP. Those skilled in the art would be able
to select
the most appropriate viscosity of the flooding fluid for the particular well.
Viscosity, as
described herein, is measured using a rheometer with an R1B1configuration at a
shear
rate of about 7.36 s-1 and a temperature of about 72 F,
For convenience, certain terms employed in the specification, examples, and
appended claims are listed here.
Definitions of specific functional groups and chemical terms are described in
more detail below. For purposes of this invention, the chemical elements are
identified in
accordance with the Periodic Table of the Elements, CAS version, Handbook of
Chemistry and Physics, 751h Ed., inside cover, and specific functional groups
are
generally defined as described therein. Additionally, general principles of
organic
chemistry, as well as specific functional moieties and reactivity, are
described in Organic
Chemistry, Thomas Sorrell, University Science Books, Sausalito: 1999, the
entire
contents of which are incorporated herein by reference.
Certain compounds of the present invention may exist in particular geometric
or
stereoisomeric forms. The present invention contemplates all such compounds,
including
cis- and trans-isomers, R- and S-enantiomers, diastereomers, (D)-isomers, (0-
isomers,
the racemic mixtures thereof, and other mixtures thereof, as falling within
the scope of
the invention. Additional asymmetric carbon atoms may be present in a
substituent such
as an alkyl group. All such isomers, as well as mixtures thereof, are intended
to be
included in this invention.
Isomeric mixtures containing any of a variety of isomer ratios may be utilized
in
accordance with the present invention. For example, where only two isomers are
combined, mixtures containing 50:50, 60:40, 70:30, 80:20, 90:10, 95:5, 96:4,
97:3, 98:2,
99:1, or 100:0 isomer ratios are all contemplated by the present invention.
Those of
ordinary skill in the art will readily appreciate that analogous ratios are
contemplated for
more complex isomer mixtures.
The term "aliphatic," as used herein, includes both saturated and unsaturated,
nonaromatic, straight chain (i.e. unbranched), branched, acyclic, and cyclic
(i.e.
carbocyclic) hydrocarbons, which are optionally substituted with one or more
functional
- 42 -
CA 02904728 2015-09-17
, =
groups. As will be appreciated by one of ordinary skill in the art,
"aliphatic" is intended
herein to include, but is not limited to, alkyl, alkenyl, alkynyl, cycloalkyl,
cycloalkenyl,
and cycloalkynyl moieties. Thus, as used herein, the term "alkyl" includes
straight,
branched and cyclic alkyl groups. An analogous convention applies to other
generic
5 terms such as "alkenyl", "alkynyl", and the like. Furthermore, as used
herein, the terms
"alkyl", "alkenyl", "alkynyl", and the like encompass both substituted and
unsubstituted
groups. In certain embodiments, as used herein, "aliphatic" is used to
indicate those
aliphatic groups (cyclic, acyclic, substituted, unsubstituted, branched or
unbranched)
having 1-20 carbon atoms. Aliphatic group substituents include, but are not
limited to,
10 any of the substituents described herein, that result in the formation
of a stable moiety
(e.g., aliphatic, alkyl, alkenyl, alkynyl, heteroaliphatic, heterocyclic,
aryl, heteroaryl,
acyl, oxo, imino, thiooxo, cyano, isocyano, amino, azido, nitro, hydroxyl,
thiol, halo,
aliphaticamino, heteroaliphaticamino, alkylamino, heteroalkylamino, arylamino,
heteroarylamino, alkylaryl, arylalkyl, aliphaticoxy, heteroaliphaticoxy,
alkyloxy,
15 heteroalkyloxy, aryloxy, heteroaryloxy, aliphaticthioxy,
heteroaliphaticthioxy,
alkylthioxy, heteroalkylthioxy, arylthioxy, heteroarylthioxy, acyloxy, and the
like, each
of which may or may not be further substituted).
The term "alkane" is given its ordinary meaning in the art and refers to a
saturated hydrocarbon molecule. The term "branched alkane" refers to an alkane
that
20 includes one or more branches, while the term "unbranched alkane" refers
to an alkane
that is straight-chained. The term "cyclic alkane" refers to an alkane that
includes one or
more ring structures, and may be optionally branched. The term "acyclic
alkane" refers
to an alkane that does not include any ring structures, and may be optionally
branched.
The term "alkene" is given its ordinary meaning in the art and refers to an
25 unsaturated hydrocarbon molecule that includes one or more carbon-carbon
double
bonds. The term "branched alkene" refers to an alkene that includes one or
more
branches, while the term "unbranched alkene" refers to an alkene that is
straight-chained.
The term "cyclic alkene" refers to an alkene that includes one or more ring
structures,
and may be optionally branched. The term "acyclic alkene" refers to an alkene
that does
30 not include any ring structures, and may be optionally branched.
The term "aromatic" is given its ordinary meaning in the art and refers to
aromatic carbocyclic groups, having a single ring (e.g., phenyl), multiple
rings (e.g.,
biphenyl), or multiple fused rings in which at least one is aromatic (e.g.,
1,2,3,4-
- 43 -
CA 02904728 2015-09-17
tetrahydronaphthyl, naphthyl, anthryl, or phenanthryl). That is, at least one
ring may
have a conjugated pi electron system, while other, adjoining rings can be
cycloalkyls,
cycloalkenyls, cycloalkynyls, aryls and/or heterocyclyls.
The term "aryl" is given its ordinary meaning in the art and refers to
aromatic
carbocyclic groups, optionally substituted, having a single ring (e.g.,
phenyl), multiple
rings (e.g., biphenyl), or multiple fused rings in which at least one is
aromatic (e.g.,
1,2,3,4-tetrahydronaphthyl, naphthyl, anthryl, or phenanthryl). That is, at
least one ring
may have a conjugated pi electron system, while other, adjoining rings can be
cycloalkyls, cycloalkenyls, cycloalkynyls, aryls and/or heterocyclyls. The
aryl group
to may be optionally substituted, as described herein. Substituents
include, but are not
limited to, any of the previously mentioned substitutents, i.e., the
substituents recited for
aliphatic moieties, or for other moieties as disclosed herein, resulting in
the formation of
a stable compound. In some cases, an aryl group is a stable mono- or
polycyclic
unsaturated moiety having preferably 3-14 carbon atoms, each of which may be
substituted or unsubstituted.
The term "amine" is given its ordinary meaning in the art and refers to a
primary
(-NH2), secondary (-NHRõ), tertiary (-NRxRy), or quaternary (-N+RxRyR,) amine
(e.g.,
where Rx, Ry, and R., are independently an aliphatic, alicyclic, alkyl, aryl,
or other
moieties, as defined herein).
The term "amide" is given its ordinary meaning in the art and refers to a
compound containing a nitrogen atom and a carbonyl group of the structure
RõCONRyR,
(e.g., where Rx, Ry, and Rz are independently an aliphatic, alicyclic, alkyl,
aryl, or other
moieties, as defined herein).
These and other aspects of the present invention will be further appreciated
upon
consideration of the following Examples, which are intended to illustrate
certain
particular embodiments of the invention but are not intended to limit its
scope, as defined
by the claims.
Examples
Example 1:
CMG STARS is a chemical simulator to model special hydrocarbon displacement
and recovery processes e.g. water flooding such as mobility control polymer
flood, foam
diversion, in-situ steam drive, fines migration, gel-polymer process, etc. As
such not
- 44 -
CA 02904728 2015-09-17
only equations describing fluid movement are used, but also there are other
auxiliary
equations such reaction kinetics, solid transport, steam dissipation etc. The
solution
framework is different than a fully compositional model where hydrocarbon
phase is
modeled using several individual single or pseudo components whereas here bulk
components are modeled as is, because of the additional components needed to
model
the complex advanced processes. For example, to model mobility control polymer
process enhanced with microemulsion dosages, oil, water, polymer, emulsion or
microemulsion, and solution gas can be the selected as the chemical species.
There is
generally one conservation equation for each chemical species for which a
separate
accounting is desired, along with several equations describing phase
equilibrium between
phases. A set of these equations exist for each region of interest, which may
be a
discretized grid block. Lastly, there are equations describing the operating
condition of
each injection and production well.
To demonstrate the relative effects of polymer and emulsion/microemulsion
water flooding fluids, a sample reservoir with typical rock and fluid
properties (similar to
observed in reservoirs deemed to be candidates for polymer-augmented
waterflooding)
was selected for the CMG STARS simulation. FIG. 2 shows a schematic of the CMG-
STARS simulation model wells and layers and the permeability of each layer.
Five
different scenarios were simulated:
1. Waterflood + Polymer + Emulsion/Microemulsion (ME)
2. Waterflood + ME
3. Waterflood + ME (1 month slug)
4. Waterflood + Polymer
5. Waterflood
For all the scenarios, the reservoir was initially waterflooded for 1
simulated
year. For the cases where ME was added (scenarios 1 and 2), ME was added for 1
year.
When ME slug was used (scenario 3), the ME was added for one month. In the
cases
where polymer was present (scenarios 1 and 4), polymer was added starting from
the 2nd
year with a tapered slug in the 5th year. Waterflood was continued for another
10 years
thereafter. All other operational conditions were the same for all the
scenarios. Polymers
having a viscosity of 70 cp and a molecular weight of 100,000 were used. In
scenarios 1
and 4, for the first 3 years 750 ppm (7.5 wt%) polymer was injected and for
the last year
a tapered slug of 375 ppm (3.75 wt%) polymer was injected. Oil viscosity was
10 cP.
-45-
CA 02904728 2015-09-17
. .
The wells were simulated as comprising one central injector constrained at a
rate
of 4,000 bwpd (barrels of water per day), four corner producers constrained at
1,000
bbl/day (barrels per day) of total liquid, and all layers of the simulation
were open for
both injection and production.
5 Furthermore, there were inputs for adsorption for both polymer and ME.
The
scenarios were run until the end of the waterflood. The oil recovery rates
(FIG. 3A) and
cumulative production (FIG. 3B) at the end of the simulation were then
compared to
gauge incremental gains over waterflood alone, which is the baseline. The oil
saturation
in a given layer (FIGs. 4A-4E) was also determined. The best case scenario
shows most
10 mobilized and displaced oil thereby showing lower remaining oil
saturation.
FIG. 3A shows the oil recovery rate in bbl/day. The combination of
emulsion/microemulsion and polymer injected together yielded unexpected
benefits over
injecting either emulsion/microemulsion or polymer by themselves or by
injecting them
sequentially. The benefit of co-injecting expressed by recovery of barrels per
day was
15 generally more than a linear combination of the emulsion/microemulsion
alone flood
recovery and polymer alone flood recovery.
FIG. 3C shows the water production rate as a fraction of the total produced
fluids
from the well. The combination of emulsion/microemulsion and polymer injected
together yielded unexpected benefits over injecting either
emulsion/microemulsion or
20 polymer individually or by injecting them sequentially. FIG. 3C shows
that significant
reduction in water production (measured in terms of the ratio of water
production rate
versus the total water and oil production rates) could be achieved with the
use of
emulsion/microemulsion in combination with the injected polymer. The resulting
decrease in water cut when co-injecting was generally more than a linear
combination of
25 the decrease from emulsion/microemulsion only and polymer only floods.
FIGs. 4A-4E show the simulated oil saturation of a layer of the model after
each
simulated scenario. FIG. 4B demonstrates that the combination of
emulsion/microemulsion and polymer result in the lowest simulated oil
saturation
compared to all of the other simulated scenarios.
30 FIG. 4A & 4B demonstrate that the use of emulsion/microemulsion along
with
the polymer resulted in more of the residual oil to be produced. More residual
oil was left
in the scenario where no emulsion/microemulsion was used (Scenario 4) as
compared to
- 46 -
CA 02904728 2015-09-17
the scenario where emulsion/microemulsion was used with the injected polymer
(Scenario 1).
FIG. 4C & 4D demonstrate that the use of emulsion/microemulsion along with
the injected water (during a waterflood operation) caused more of the residual
oil to be
produced. More residual oil was left in the scenario where no
emulsion/microemulsion
was used (Scenario 5) compared to the case where emulsion/microemulsion was
used
with the injected water (Scenario 2).
FIG. 4E demonstrate that the use of emulsion/microemulsion prior to a polymer
flood operation is also beneficial, where less amount of residual oil is left
in this scenario
(Scenario 3).
However, comparing all the above scenarios, it was observed that more oil
could
be recovered if emulsion/microemulsion was used with polymer during a polymer
flood
(Scenario 1), as observed in FIG. 3B.
While several embodiments of the present invention have been described and
illustrated herein, those of ordinary skill in the art will readily envision a
variety of other
means and/or structures for performing the functions and/or obtaining the
results and/or
one or more of the advantages described herein, and each of such variations
and/or
modifications is deemed to be within the scope of the present invention. More
generally,
those skilled in the art will readily appreciate that all parameters,
dimensions, materials,
and configurations described herein are meant to be exemplary and that the
actual
parameters, dimensions, materials, and/or configurations will depend upon the
specific
application or applications for which the teachings of the present invention
is/are used.
Those skilled in the art will recognize, or be able to ascertain using no more
than routine
experimentation, many equivalents to the specific embodiments of the invention
described herein. It is, therefore, to be understood that the foregoing
embodiments are
presented by way of example only and that, within the scope of the appended
claims and
equivalents thereto, the invention may be practiced otherwise than as
specifically
described and claimed. The present invention is directed to each individual
feature,
system, article, material, kit, and/or method described herein. In addition,
any
combination of two or more such features, systems, articles, materials, kits,
and/or
methods, if such features, systems, articles, materials, kits, and/or methods
are not
mutually inconsistent, is included within the scope of the present invention.
- 47 -
CA 02904728 2015-09-17
The indefinite articles "a" and "an," as used herein in the specification and
in the
claims, unless clearly indicated to the contrary, should be understood to mean
"at least
one."
The phrase "and/or," as used herein in the specification and in the claims,
should
be understood to mean "either or both" of the elements so conjoined, i.e.
elements that
are conjunctively present in some cases and disjunctively present in other
cases. Other
elements may optionally be present other than the elements specifically
identified by the
"and/or" clause, whether related or unrelated to those elements specifically
identified
unless clearly indicated to the contrary. Thus, as a non-limiting example, a
reference to
"A and/or B," when used in conjunction with open-ended language such as
"comprising"
can refer, in one embodiment, to A without B (optionally including elements
other than
B); in another embodiment, to B without A (optionally including elements other
than A);
in yet another embodiment, to both A and B (optionally including other
elements); etc.
As used herein in the specification and in the claims, "or" should be
understood
to have the same meaning as "and/or" as defined above. For example, when
separating
items in a list, "or" or "and/or" shall be interpreted as being inclusive,
i.e. the inclusion
of at least one, but also including more than one, of a number or list of
elements, and,
optionally, additional unlisted items. Only terms clearly indicated to the
contrary, such as
"only one of' or "exactly one of," or, when used in the claims, "consisting
of," will refer
to the inclusion of exactly one element or a list of elements. In general, the
term "or" as
used herein shall only be interpreted as indicating exclusive alternatives
(i.e. "one or the
other but not both") when preceded by terms of exclusivity, such as "either,"
"one of,"
"only one of," or "exactly one of." "Consisting essentially of," when used in
the claims,
shall have its ordinary meaning as used in the field of patent law.
As used herein in the specification and in the claims, the phrase "at least
one," in
reference to a list of one or more elements, should be understood to mean at
least one
element selected from any one or more of the elements in the list of elements,
but not
necessarily including at least one of each and every element specifically
listed within the
list of elements and not excluding any combinations of elements in the list of
elements.
This definition also allows that elements may optionally be present other than
the
elements specifically identified within the list of elements to which the
phrase "at least
one" refers, whether related or unrelated to those elements specifically
identified. Thus,
as a non-limiting example, "at least one of A and B" (or, equivalently, "at
least one of A
- 48 -
CA 02904728 2015-09-17
or B," or, equivalently "at least one of A and/or B") can refer, in one
embodiment, to at
least one, optionally including more than one, A, with no B present (and
optionally
including elements other than B); in another embodiment, to at least one,
optionally
including more than one, B, with no A present (and optionally including
elements other
than A); in yet another embodiment, to at least one, optionally including more
than one,
A, and at least one, optionally including more than one, B (and optionally
including other
elements); etc.
In the claims, as well as in the specification above, all transitional phrases
such as
"comprising," "including," "carrying," "having," "containing," "involving,"
"holding,"
and the like are to be understood to be open-ended, i.e. to mean including but
not limited
to. Only the transitional phrases "consisting of' and "consisting essentially
of' shall be
closed or semi-closed transitional phrases, respectively, as set forth in the
United States
Patent Office Manual of Patent Examining Procedures, Section 2111.03.
- 49 -
