Note: Descriptions are shown in the official language in which they were submitted.
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FOAMING AGENT COMPOSITION AND METHOD FOR REMOVING
HYDROCARBON LIQUIDS FROM SUBTERRANEAN WELLS
RELATED APPLICATIONS
[0001] The present application is based on and claims priority to U.S.
Provisional Patent application Serial No. 62/432,894 filed on December 12,
2016,
and claims priority to European Patent application No. 17161961.2 filed on
March
21, 2017, which are both incorporated herein by reference.
BACKGROUND
[0002] In order to harvest and collect natural gas, in one embodiment, a
bore is
formed into the surface above a natural gas reserve. When first completed,
many
natural gas wells have sufficient reservoir pressure for flow to be
established from
the reservoir to the surface. A typical problem of gas wells, however, is that
they
often produce and accumulate liquids. The liquids may comprise water or
aqueous solutions and/or hydrocarbon compounds, known as hydrocarbon
condensates. As gas production continues, the liquids have a tendency to
accumulate within the well. As the liquids accumulate the reservoir pressure
declines and as pressure declines, the velocity of the gases in the well
decreases.
Eventually, the accumulated liquids can render the well uneconomical and/or
even
stop production of the gas products. For example, as the bottom well pressure
approaches reservoir shut-end pressure, gas flow stops and all liquid
accumulates
at the bottom of the tubing that makes up the well.
[0003] Liquids such as hydrocarbon condensates can also build up and cause
problems in oil wells. The hydrocarbon liquids, for instance, can create
problems
in the wells especially when the well also contains natural gas or other
hydrocarbon gases that are being vented and/or collected.
[0004] One common approach to temporarily restoring flow is to vent the
well to
the atmosphere, which is known as well "blow down." Venting the well to the
atmosphere, however, can result in a significant amount of loss of the gas
products
being collected.
[0005] In view of the above, those skilled in the art have attempted to
devise
different ways in order to remove the liquid that accumulates within the
natural gas
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and oil wells. For instance, artificial lift methods that have been proposed
in the
past in order to deliquify gas wells include pumping the liquids using a
suitable
pumping device. For instance, those skilled in the art have attempted to
remove
the liquids through cavity pumping, submersible pumping, and hydraulic
pumping.
The use of pumps, however, has many limitations. For instance, pumps have
limited head capacity. In addition, pumps cannot withstand many of the high
temperatures experienced within the wells. The use of pumps also represents a
significant capital cost and manpower requirement, and can complicate the
process.
[0006] Another method used in the past in order to remove liquids within
wells
is to use plungers, such as tubing plungers or casing plungers. The use of
plungers, however, typically requires gas production to stop while sufficient
pressure builds to lift the plunger to the surface of the well.
[0007] Those skilled in the art have also proposed placing soap sticks or
other
foaming agents into a well that causes the liquid portion to foam. The soap
sticks,
for instance, can include a foaming agent such as an alkyl benzene sulfonate,
an
alcohol ether sulfonate, alkylnapthalene sulfonate, alkyldiphenyloxide
disulfonate,
and the like. Other foaming agents that have been proposed for use in the past
include alkyl quaternary ammonium chlorides, dialkyl quaternary ammonium
chlorides, alkyl amido betaines, and alkyl imidazolines. In still another
embodiment, those skilled in the art have proposed using siloxane polymers as
foaming agents to remove liquids, primarily aqueous liquids from gas and oil
wells.
Causing the unwanted liquids to foam, for instance, greatly reduces the amount
of
pressure needed in order to bring the liquid components to the surface. Thus,
by
foaming the liquid, reservoir pressure can be used to remove the liquid.
[0008] Problems have been experienced in using foaming agents, however.
For instance, the above foaming agents are capable of foaming water and
aqueous solutions but are not capable of sufficiently foaming hydrocarbons.
Thus,
the foaming agents are only successful when the liquid in the well is
comprised of
primarily water.
[0009] In view of the above, a need currently exists for a process and
method
for removing liquids from a well, particularly natural gas and oil wells. For
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instance, a need exists for a foaming composition or foaming agent composition
capable of foaming hydrocarbon liquids, such as hydrocarbon condensates.
SUMMARY
[0010] In general, the present disclosure is directed to a foaming or
foamable
composition capable of foaming liquids containing substantial amounts of
hydrocarbons, such as hydrocarbon condensates. The composition is particularly
well suited for use in a method for removing liquids from a tubular structure,
such
as subterranean wells. The tubular structure, for instance, may be comprised
of or
attached to a gas or oil well, a well bore, or a pipeline. The composition is
capable
of foaming a liquid that contains one or more hydrocarbons in an amount
greater
than about 40% by weight, such as greater than 50% by weight, such as greater
than 60% by weight. The composition, in fact, is capable of foaming a liquid
comprised of only hydrocarbons. In accordance with the present disclosure, the
composition contains a quaternary organosilane foaming agent.
[0011] For example, in one embodiment, the present disclosure is directed
to a
method for removing a liquid from a tubular structure which includes a step of
adding a composition to a liquid contained in the tubular structure. The
composition comprises a foaming agent, and particularly a quaternary
organosilane. After the composition is added to the liquid, a foamed liquid is
formed within the tubular structure. More particularly, the composition is
combined
with the liquid in a manner that causes the liquid to form a foam, such as
through
agitation. The liquid can primarily comprise hydrocarbons alone or in
combination
with other liquids such as water. Once formed into a foam, the foamed liquid
is
brought to the surface of the tubular structure such as the gas or oil well.
At the
surface, the foam dissipates and the resulting liquid, which may also be
combined
with gases, can be fed to a separator. The separator can comprise a pressure
vessel for separating the entering fluid into gaseous and liquid components.
The
liquid components can be further separated into a hydrocarbon component and a
water component.
[0012] In one embodiment, the tubular structure comprises a gas or oil well
that
includes a pressurized gas. The reservoir gas pressure within the tubular
structure
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not only assists in forming the foam but also can be used to remove the foamed
liquid from the tubular structure after the foam is formed.
[0013] In one embodiment the quaternary organosilane can have the following
formula (I):
y1y2y3si-A_Q+R1 R2R3 (I)
[0014] wherein:
[0015] Y1,Y2, Y3 represent independently from each other R or RO wherein
each R represents independently from each other a C14 alkyl group;
[0016] A represents a C1_4alkanediy1 or a C2_4 alkenediyl group
[0017] Q represents a nitrogen or phosphorous atom;
[0018] R1, R2and R3 represent independently from each other a Ci_28alkyl
group wherein at least one alkyl group has at least eight carbon atoms; and
[0019] X represents chloride, bromide, fluoride, iodide, acetate or
tosylate.
[0020] In a preferred embodiment, the quaternary organosilane can have the
following formula (II):
(R0)3Si¨A¨Q R1R2R3 X- (II)
[0021] wherein
[0022] each R represents independently from each other a C14 alkyl group;
[0023] A represents a C1_4alkanediy1 or a C2_4 alkenediyl group
[0024] Q represents a nitrogen or phosphorous atom;
[0025] R1, R2 and R3 represent independently from each other a C128 alkyl
group wherein at least one alkyl group has at least eight carbon atoms; and;
[0026] X- represents chloride, bromide, fluoride, iodide, acetate or
tosylate.
[0027] Preferably the quaternary organosilane comprises a halide salt of a
quaternary ammonium silane. More preferably the quaternary organosilane is 3-
(trimethoxysily1) propyldimethyloctadecyl ammonium chloride.
[0028] As shown above, silanes that may be used according to the present
disclosure, in one embodiment, only contain a single silicon atom in the
molecule
and thus exclude siloxanes. The non-polymeric silane compounds can generally
have a molecular weight of less than about 900, such as less than about 800,
such
as less than about 700, such as less than about 600. The molecular weight of
the
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silane molecule is generally greater than about 50, such as greater than about
100.
[0029] In one embodiment, in addition to the quaternary organosilane
foaming
agent, the composition can contain a solvent, preferably a non-aqueous
solvent.
When containing a non-aqueous solvent, the composition can have a low water
content prior to contact with the liquid in the tubular structure. For
example, water
can be contained in the composition in an amount less than about 5% by weight,
more preferably less than about 2% by weight, most preferably in an amount
less
than about 1`)/0 by weight.
[0030] In general, any suitable non-aqueous solvent can be combined with
the
quaternary organosilane as long as the solvent does not interfere with the
foaming
properties of the quaternary organosilane and is compatible with the liquid in
the
tubular structure. For example, the non-aqueous solvent may be selected from a
group comprising an alcohol, a benzene derivative, a ketone or an ester or
from
mixtures of two or more of the aforementioned.
[0031] In one embodiment, the composition contains the non-aqueous solvent
in an amount from 25% to 75% by weight and contains the quaternary
organosilane foaming agent in an amount of from 75% to 25% by weight. In one
embodiment, the composition is added to the liquid in the tubular structure in
an
amount such that the concentration of the quaternary organosilane in the
resulting
mixture is from 250 ppm to 5000 ppm.
[0032] After the foamed liquid is removed from the tubular structure, the
foamed
liquid can be further processed as desired. In one embodiment, for instance,
hydrocarbons contained in the foamed liquid can be separated and reused.
[0033] The present disclosure is also directed to a composition for
removing
liquids from gas and oil wells. The composition comprises a quaternary
organosilane as described above. In one embodiment, the quaternary
organosilane foaming agent as described above is combined with a non-aqueous
solvent. The composition can further comprise one or more additives. For
instance, the additives may comprise a corrosion inhibitor, a scale inhibitor,
and/or
a hydrogen sulfide scavenger. For instance, in one embodiment, the foaming
agent composition contains a hydrogen sulfide scavenger that comprises glyoxal
or 1,3-dimethyloI-5,5-dimethylhydantion. In one embodiment, the non-aqueous
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solvent comprises naphtha or an aromatic petroleum distillate, such as a
benzene
derivative. For instance, the solvent may be selected from naphtha, xylene, or
toluene or mixtures thereof.
[0034] Of particular advantage, the composition of the present disclosure
is not
only well suited to forming a foam with a liquid containing substantial
amounts of
one or more hydrocarbons, but also produces a foam that dissipates relatively
quickly. In this manner, the composition is capable of quickly foaming a
hydrocarbon liquid in order to remove the liquid from a tubular structure and
also
has a relatively short foam half-life allowing for easy handling of the
recovered
liquid and separation of the hydrocarbons from aqueous components after
removal. For example, the composition of the present disclosure can have a
foam
half-life in kerosene of less than 180 seconds when the concentration of the
quaternary organosilane in kerosene is 1000 ppm on a weight basis. For
example,
the foam can have a half-life of less than 120 seconds, such as less than 90
seconds, such as less than 60 seconds. When the concentration of the
quaternary
organosilane in kerosene is 1500 ppm on a weight basis, the composition can
have a foam half-life in kerosene of less than about 240 seconds, such as less
than about 180 seconds, such as less than about 120 seconds, such as less than
about 100 seconds.
[0035] Other features and aspects of the present disclosure are discussed
in
greater detail below.
DETAILED DESCRIPTION
[0036] In this text the following meanings are used if not otherwise
stated.
[0037] The term "halogen" or "halide" means F, Cl, Br or I or fluoride (F),
chloride (Cr), bromide (BC), or iodide (I-).
[0038] The term "alkyl" refers to linear or branched alkyl; preferably
linear alkyl.
The term alkane means a linear or branched alkane.
[0039] The term "alkanediyl" as used herein, refers to divalent saturated
aliphatic group, with one or two saturated carbon atom(s) as the point(s) of
attachment, a linear or branched, cyclo, cyclic or acyclic structure, no
carbon-
carbon double or triple bonds, and no atoms other than carbon and hydrogen.
The
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groups, ¨CH2¨ (methylene), ¨CH2CH2¨, ¨CH2C(CH3)2CH2¨, and ¨
CH2CH2CH2¨are non-limiting examples of alkanediyl groups.
[0040] The term "alkenediyl" as used herein, refers to a divalent
unsaturated
aliphatic group, with two carbon atoms as points of attachment, a linear or
branched, cyclo, cyclic or acyclic structure, at least one nonaromatic carbon-
carbon double bond, no carbon-carbon triple bonds, and no atoms other than
carbon and hydrogen. The groups, ¨CH=CH¨, ¨CH=C(CH3)CH2¨, -CH2-
CH=CH-CH2-, -CH=CH-CH2-CH2-. and ¨CH=CHCH2¨ are non-limiting examples
of alkenediyl groups.
[0041] The term "alcohol" as used herein, refers to any of a class of
organic
compounds characterized by one or more hydroxyl ( -OH) groups attached to a
carbon atom of an alkyl group (hydrocarbon chain). The alcohol can be primary,
secondary or tertiary.
[0042] In the following text "hydrocarbon" as used herein refers to an
organic
compound consisting entirely of hydrogen and carbon. Hydrocarbons may be
aromatic hydrocarbons (arenes), alkanes, alkenes, cycloalkanes and alkyne-
based
compounds. Hydrocarbons may be saturated hydrocarbons (alkanes) composed
entirely of single bonds and are saturated with hydrogen. The general formula
for
saturated hydrocarbons is C,1-12"2 (assuming noncyclic structures).
Hydrocarbons
may be unsaturated hydrocarbons having one or more double or triple bonds
between carbon atoms such as alkenes and alkynes as defined above.
Hydrocarbons may be cycloalkanes, which are hydrocarbons containing one or
more carbon rings to which hydrogen atoms are attached. Hydrocarbons may be
aromatic hydrocarbons, also known as arenes, are hydrocarbons that have at
least
one aromatic ring. Hydrocarbons may be a liquid hydrocarbon. The liquid
hydrocarbon may be any type of liquid hydrocarbon including, but not limited
to,
crude oil, heavy oil, processed residual oil, bituminous oil, coker oils,
coker gas
oils, fluid catalytic cracker feeds, gas oil, naphtha, fluid catalytic
cracking slurry,
diesel fuel, fuel oil, jet fuel, gasoline, and kerosene.
[0043] The term "a mixture thereof" as used herein, refers to a mixture of
two or
more of the aforementioned compounds.
[0044] The term a "tubular structure" as used herein, refers to a pipe
through
which a gas or oil can be transported. The tubular structure, for example, can
be a
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subterranean well. The tubular structure may be comprised of or attached to a
gas
or oil well, a well bore, or a pipeline.
[0045] The term "fluid" refers to a liquid, a gas, or mixtures thereof.
[0046] It is to be understood by one of ordinary skill in the art that the
present
discussion is a description of exemplary embodiments only, and is not intended
as
limiting the broader aspects of the present disclosure.
[0047] In general, the present disclosure is directed to a composition and
to a
method for removing hydrocarbon liquids from subterranean wells by foaming the
hydrocarbon liquids within the well. For example, in one embodiment, the
composition is particularly well suited for removing hydrocarbon liquids from
gas
and oil wells. In accordance with the present disclosure, the composition
contains
a quaternary organosilane foaming agent, such as a halide salt of a quaternary
ammonium silane.
[0048] The composition of the present disclosure offers various benefits
and
advantages when attempting to remove hydrocarbon liquids from tubular
structures through foam formation. For instance, the composition of the
present
disclosure is particularly well suited to foaming liquids containing
substantial
amounts of hydrocarbons, such as hydrocarbon condensates, that may
accumulate in oil and gas wells. For instance, in the past, problems have been
experienced in attempting to foam liquids in oil and gas wells when the
liquids
contain less than about 80% water. The composition of the present disclosure,
on
the other hand, can foam liquids containing less than 80% water, such as less
than
60% water, such as less than 40% water, such as less than 20% water, such as
less than 10% water by weight. For example, the composition of the present
disclosure can foam liquids containing hydrocarbons in an amount greater than
about 20%, such as in an amount greater than about 40%, such as in an amount
greater than about 50%, such as in an amount greater than about 60%, such as
in
an amount greater than about 70%, such as in an amount greater than about 80%,
such as even in amounts greater than about 90% by weight. The composition, in
fact, can foam liquids that contain substantially no water (less than about 5%
by
weight, such as less than 2% by weight, such as less than about 1`)/0 by
weight
water,) and are made almost entirely from hydrocarbon liquids.
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[0049] In addition to being capable of foaming hydrocarbon liquids, the
composition of the present disclosure also rapidly produces foam, and, in
turn,
produces a foam that also rapidly dissipates. This provides various advantages
and benefits when removing liquids from tubular structures, such as oil and
gas
wells. For instance, during the process, a foam rapidly develops that allows
for
liquids in the well to rise and be removed from the well. The composition also
creates a foam that breaks at the well surface. By breaking at the surface,
the
liquid collected from the well can be easily handled and further processed.
Dissipation of the foam, for instance, allows for easy separation of the
components
contained in the liquid. For instance, in one embodiment, any hydrocarbons
contained in the liquid can be separated from the remainder of the liquid. For
example, liquids removed from the well in accordance with the present
disclosure
can be fed to a separator that separates the liquids into a hydrocarbon
component
and an aqueous component.
[0050] The composition of the present disclosure may comprise a foaming
agent, such as a quaternary organosilane, in combination with a solvent.
Preferably the solvent is a non-aqueous solvent. The composition is
particularly
well suited for removing liquids from tubular structures, such as gas wells,
oil wells,
or a pipeline. In one embodiment, for instance, the composition can be used to
remove liquids from a gas well, such as a natural gas well. In accordance with
the
present disclosure, the composition can be added to the well continuously or
in a
batch wise manner. In one embodiment, for instance, the composition can be
continuously added to the well using a string or capillary extending into the
well
bore. Of particular advantage, the composition is well suited to withstanding
the
temperatures and pressures that may exist within a gas or oil well. When
removing liquids from a well, the reservoir gas pressure within the well can
be
used to assist in forming a foam between the composition and a liquid
contained in
the well and can also be used as the pressure needed in order to remove the
foamed liquid from the well.
[0051] In addition to gas wells, the composition of the present disclosure
can
also be used to remove liquids, such as hydrocarbon condensates, from oil
wells.
In some oil wells, sufficient reservoir gas pressure exists capable of not
only
facilitating foam formation but also sufficient to rise the foamed liquid to
the top of
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the well. In other embodiments, however, artificial gas pressure can be
introduced
into the well for removing the foamed liquid. For instance, an inert gas, such
as
nitrogen, can be pumped into the well for facilitating foam formation and for
providing sufficient pressure to bring the foamed liquid to the surface.
[0052] Quaternary organosilanes have been found to be particularly well
suited
for foaming liquids in accordance with the present disclosure. Quaternary
organosilanes are unique due to the presence of a polar cationic nitrogen and
a
non-polar organic group, which makes them amphiphilic in nature. Their
cationic
nature makes them water soluble and/or dispersible, while the non-polar
hydrocarbon component makes them easily soluble and/or dispersible in non-
polar
mixtures. Although unknown, it is believed that the amphiphilic behavior of
the
quaternary organosilane compounds helps stabilize a non-polar/polar interface
such as a water condensate mixture, thereby making quaternary organosilanes
excellent foam producers.
[0053] The quaternary organosilane composition, according to certain
embodiments of the present disclosure, may comprise one or more quaternary
organosilane compounds comprising at least one alkoxy group. Preferably, the
at
least one alkoxy group comprises ethylene glycol or polyethylene glycol
functionality. The at least one alkoxy group can comprise ethylene glycol or
polyethylene glycol functionality bonded to a silicon atom.
[0054] In certain embodiments, the one or more quaternary organosilane
compounds can have the following formula (I):
y1y2y3si-A_Q-FR1R2R3 k (I)
[0055] wherein:
[0056] Y1,Y2, Y3 represent independently from each other R or RO wherein
each R represents independently from each other a C1_4 alkyl group;
[0057] A represents a C1_4 alkanediyl or a C2_4 alkenediyl group;
[0058] Q represents a nitrogen or phosphorous atom;
[0059] R1, R2 and R3 represent independently from each other a C1_28 alkyl
group wherein at least one alkyl group has at least eight carbon atoms, --
CH2C6H5,
--CH2CH2OH, --CH2OH, and --(CH2)xNHC(0)R6 wherein x is an integer of two to
ten and R6 is a C1_12-perfluoroalkyl group; and
[0060] X represents chloride, bromide, fluoride, iodide, acetate or
tosylate.
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[0061] In one embodiment, the silanes are trialkoxysilyl compounds having
the
general formula (II)
(R0)3Si¨A¨Q+R1R2R3 X- (II)
[0062] wherein
[0063] each R represents independently from each other a C1_4 alkyl group;
[0064] A represents a C1_4 alkanediyl or a C2_4 alkenediyl group;
[0065] Q represents a nitrogen or phosphorous atom;
[0066] R1, R2 and R3 represent independently from each other a C1_28 alkyl
group wherein at least one alkyl group has at least eight carbon atoms; and;
[0067] X- represents chloride, bromide, fluoride, iodide, acetate or
tosylate.
[0068] Exemplary silanes for this disclosure are those silanes having the
formula
(CH30)3Si(C1-12)3N (C113)2C1gH37C1- and
(CH30)3Si(C}12)3-N Q13(Cot)2C
[0069] Specific silanes within the scope of the disclosure are represented
by
the following:
(CH30)3Si(c112)3N+(CII3)2C181-137a-,
(0130)3Si(o12)3N+(e113)2C" H37Br
(CH30)3Si(CH2)3N (C 10H21)2CH3C1
(CH 30)3S i(CH2)3N (C10112 i)2CH3Br
(CH 30)3Si(CH2)3N+ (CH3)3CI
(CH30)3SiCH2CH2CH2P (C6H 5)3 CI -
(CH30)3SICH2CH2CH2P+(C6H5)3Br
(CH30)3SiCH2CH2CH2P (CH3)3CI- ,
=(CH30)3SiCH2CH2C H 2P +(C6H13)3C1-
(CH3)3 Si(CH2)3N + (CH 3)2C12H25 a -
(CH3)3 Si(CH2)3N (C )2CH3C1
(CH3)3SP(CH 2)3N + (CH 3)2C1s1-1370-
(CH3O)3Si(CH2)3N+(Cli.02C4H9Ci¨,
(C2H50)3Si(C112)3N+ (CH3)2Ci s1&37CI
(CH30)3 Si(CH2)3N + (CH 3)2CH2C6H5CI
(CH30)3 Si(C H2)3N (CH3)2CH2CH2OHCI
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(cibo)3si(cH2)3N
\ xe
(cH3o)isi(cH2)3N+(cH3)2(cH2)5Nucx0KF2)8cF3a-,
(cH3ohucH2)3N+(c2H5ho-.
[0070] In one embodiment, the organosilane quaternary ammonium compound
for application in accordance with the method of the present disclosure is 3-
(trimethoxysily1) propyldimethyloctadecyl ammonium chloride of the formula
TH3
TH'
cH3-0¨T¨cH2¨c.2-03,-7+¨c, B1-137C1-
7 CH3
CH3
[0071] As shown above, 3-(trimethoxysily1) propyldimethyloctadecyl ammonium
chloride has an alkyl group attached to the nitrogen having a carbon chain
length
of 18 carbon atoms. In certain embodiments, this alkyl group can have a carbon
chain length of at least 8 carbon atoms, such as at least 12 carbon atoms,
such as
at least 14 carbon atoms, such as at least 16 carbon atoms. The carbon chain
length of this alkyl group can be generally less than about 28 carbon atoms,
such
as less than about 22 carbon atoms.
[0072] The foaming agent, such as the organosilane quaternary ammonium
compound as described above, can be combined with a solvent to form the
foaming agent composition in accordance with the present disclosure.
Preferably
the solvent is selected from a non-aqueous solvent. More preferably the
solvent
can comprise an organic solvent.
[0073] Suitable organic solvents should preferably not negatively impact
the
stability of the quaternary organosilane compounds. Suitable solvents are, but
are
not limited to, alcohols, naphtha, benzene derivatives, ketones or esters, or
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mixtures of two or more of the aforementioned. Preferably the organic solvents
may include at least one alcohol.
[0074] Examples of alcohols that can be used according to the present
invention are, but are not limited to methanol, ethanol, isopropanol and
glycols.
Examples of glycols and derivatives thereof that can be used are, but are not
limited to, ethylene glycol, propylene glycol, ethylene glycol monoethyl
ether,
ethylene glycol monobutyl ether, ethylene glycol dibutyl ether, ethylene
glycol
monoethyl ether acetate, ethylene glycol monohexyl ether acetate, propylene
glycol monoethyl ether, propylene glycol dibutyl ether; the mono- and
dialkylethers
of diethylene glycol such as diethylene glycol monoethyl ether, diethylene
glycol
dibutyl ether, diethylene glycol diethyl ether, and diethylene glycol
monobutyl ether
acetate.
[0075] In one embodiment, the solvent is selected from a group comprising
naphtha or an aromatic petroleum distillate, or mixtures thereof. Preferably
the
solvent may comprise naphtha or benzene derivatives. Examples include, but are
not limited to, naphtha, xylene, toluene or mixtures thereof.
[0076] Examples of ketones that can be used according to the present
invention are, but are not limited to, acetone, acetophenone, butanone,
cyclohexanone, ethyl isopropyl ketone, diacetone, isophorone, methyl isobutyl
ketone, methyl isopropyl ketone, methylethyl ketone, methylamyl ketone, and 3-
pentanone.
[0077] Examples of ester solvents that can be used according to the present
invention are, but are not limited to, preferably esters and more preferably
acetate
esters. Preferably the solvent is selected from, but not limited to, benzyl
benzoate,
more preferably from butyl acetate, methyl acetate, ethyl acetate, n-propyl
acetate,
isobutyl acetate, isoamyl acetate, isopropyl acetate, n-butyl acetate,
isobutyl
acetate, amyl acetate, sec-butyl acetate, tert-butyl acetate, ethyl
acetoacetate,
ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether
acetate.
[0078] The solvent combined with the quaternary organosilane may also
comprise a mixture of any of the solvents described above. In one embodiment,
the solvent may comprise water. In one embodiment, however, the foamable
composition is substantially free of water containing water in an amount less
than
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about 5% by weight, such as in an amount less than about 2% by weight, such as
in an amount less than about 1`)/0 by weight. In one embodiment, for instance,
the
foaming agent composition does not contain water and is water-free.
[0079] In one embodiment preferably, one or more solvents are contained in
the composition of the present disclosure in an amount greater than about 25%
by
weight, such as in an amount greater than about 40% by weight, such as in an
amount greater than about 50% by weight, such as in an amount greater than
about 60% by weight, such as in an amount greater than about 70% by weight,
such as in an amount greater than about 80% by weight, such as in an amount
greater than about 90% by weight, such as in an amount greater than about 95%
by weight. One or more solvents are preferably contained in the composition in
an
amount less than about 98% by weight, such as in an amount less than about 95%
by weight, such as in an amount less than about 90% by weight, such as in an
amount less than about 80% by weight, such as in an amount less than about 70%
by weight, such as in an amount less than about 50% by weight.
[0080] Preferably the quaternary organosilane is present in the composition
in
an amount generally greater than about 2% by weight, such as in an amount
greater than about 25% by weight, such as greater than about 35% by weight,
such as greater than about 45% by weight, such as greater than about 55% by
weight, such as greater than about 65% by weight, such as even greater than
about 70% by weight. The quaternary organosilane is preferably present in the
foaming agent composition in an amount less than about 75% by weight, such as
in an amount less than about 65% by weight, such as in an amount less than
about 55% by weight, such as in an amount less than about 45% by weight, such
as in an amount less than about 35% by weight.
[0081] The composition may further comprise one or more oil field additives
selected from the group comprising corrosion inhibitors, scale inhibitors,
emulsifiers, water clarifiers, dispersants, emulsion breakers, hydrogen
sulfide
scavengers, gas hydrate inhibitors, biocides, pH modifiers, surfactants,
synergistic
compounds, asphaltene inhibitors, paraffin inhibitors, antioxidants, pour
point
depressants, viscosity modifiers, flow back aids, friction reducers, or
crosslinking
agents. Unless otherwise specified, these additives typically are less than
5%,
such as less than 2%, such as less than 1`)/0 by weight and generally greater
than
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about 0.01% by weight. Such additives can be introduced into the well,
wellbore or
pipeline before, during or after the introduction of the foaming agent
composition,
or can be a component of said composition.
[0082] Suitable corrosion inhibitors include, but are not limited to,
amidoamines,
quaternary amines, amides, and phosphate esters.
[0083] Suitable scale inhibitors include, but are not limited to,
phosphates,
phosphate esters, phosphoric acids, phosphonates, phosphonic acids,
polyacrylam ides, salts of acrylamido-methyl propane sulfonate/acrylic acid
copolymer (AMPS/AA), phosphinated maleic copolymer (PHOS/MA), and salts of a
polymaleic acid/acrylic acid/acrylamido-methyl propane sulfonate terpolymer
(PMA/AMPS).
[0084] Suitable emulsifiers include, but are not limited to, salts of
carboxylic
acids, products of acylation reactions between carboxylic acids or carboxylic
anhydrides and amines, and alkyl, acyl and amide derivatives of saccharides
(alkyl-saccharide emulsifiers).
[0085] Suitable water clarifiers include, but are not limited to, inorganic
metal
salts such as alum, aluminum chloride, and aluminum chlorohydrate, or organic
polymers such as acrylic acid based polymers, acrylamide based polymers,
polymerized amines, alkanolamines, thiocarbamates, and cationic polymers such
as diallyldimethylammonium chloride (DADMAC).
[0086] Suitable dispersants include, but are not limited to, aliphatic
phosphonic
acids with 2-50 carbons, such as hydroxyethyl diphosphonic acid, and
aminoalkyl
phosphonic acids, e.g. polyaminomethylene phosphonates with 2-10 N atoms e.g.
each bearing at least one methylene phosphonic acid group; examples of the
latter
are ethylenediamine tetra(methylene phosphonate), diethylenetriamine
penta(methylene phosphonate) and the triamine- and tetramine-polymethylene
phosphonates with 2-4 methylene groups between each N atom, at least 2 of the
numbers of methylene groups in each phosphonate being different. Other
suitable
dispersion agents include lignin or derivatives of lignin such as
lignosulfonate and
naphthalene sulfonic acid and derivatives.
[0087] Suitable emulsion breakers include, but are not limited to,
dodecylbenzylsulfonic acid (DDBSA), the sodium salt of xylene sulfonic acid
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(NAXSA), epoxylated and propoxylated compounds, anionic cationic and nonionic
surfactants, and resins, such as phenolic and epoxide resins.
[0088] Examples of hydrogen sulfide scavengers include, but are not limited
to,
oxidants such as inorganic peroxides such as sodium peroxide, or chlorine
dioxide,
aldehydes or dialdehydes, such as C1_10 aldehydes, formaldehyde,
glutaraldehyde, (meth)acrolein or glyocxal), triazines such as monoethanol
amine
triazine, and monomethylamine triazine and hydantoins such as
hydroxyalkylhydantoins, bis(hydroxyalkyl)hydantoins and dialkylhydantoins
where
the alkyl group is a C1_6 alkyl group.
[0089] Preferably the hydrogen scavenger is selected from a group
comprising
glyoxal or bis(hydroxyalkyl)hydantoins. More preferably the hydrogen sulfide
scavenger is 1,3-Bis(hydroxymethyl)-5,5-dimethylhydantoins also known as 1,3-
dimethyloI-5,5-dimethylhydantion (DMDMH).
[0090] Suitable gas hydrate inhibitors include, but are not limited to,
thermodynamic inhibitors (THI), kinetic inhibitors (KHI), and anti-
agglomerates
(AA). Suitable thermodynamic inhibitors include, but are not limited to, NaCI
salt,
KCI salt, CaCl2 salt, MgC12 salt, NaB2 salt, formate brines (e.g. potassium
formate),
polyols (such as glucose, sucrose, fructose, maltose, lactose, gluconate,
monoethylene glycol, diethylene glycol, triethylene glycol, mono-propylene
glycol,
dipropylene glycol, tripropylene glycols, tetrapropylene glycol, monobutylene
glycol, dibutylene glycol, tributylene glycol, glycerol, diglycerol,
triglycerol, and
sugar alcohols (e.g. sorbitol, mannitol), methanol, propanol, ethanol, glycol
ethers
(such as diethyleneglycol monomethyl ether, ethylene glycol monobutyl ether),
and
alkyl or cyclic esters of alcohols (such as ethyl lactate, butyl lactate,
methylethyl
benzoate). Suitable kinetic inhibitors and anti-agglomerates include, but are
not
limited to, polymers and copolymers, polysaccharides (such as hydroxy-
ethylcellulose (H EC), carboxymethylcellulose (CMC), starch, starch
derivatives,
and xanthan), lactams (such as polyvinylcaprolactam, polyvinyl lactam),
pyrrolidones (such as polyvinyl pyrrolidone of various molecular weights),
surfactants (such as fatty acid salts, ethoxylated alcohols, propoxylated
alcohols,
sorbitan esters, ethoxylated sorbitan esters, polyglycerol esters of fatty
acids, alkyl
glucosides, alkyl polyglucosides, alkyl sulfates, alkyl sulfonates, alkyl
ester
sulfonates, alkyl aromatic sulfonates, alkyl betaine, alkyl amido betaines),
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hydrocarbon based dispersants (such as lignosulfonates, iminodisuccinates,
polyaspartates), amino acids, and proteins.
[0091] Any biocide suitable in oilfield operations may be used. A biocide
may
be included in a composition in an amount of about 0.1 ppm to about 1000 ppm
on
a weight basis. Suitable biocides include, but are not limited to, oxidizing
and non-
oxidizing biocides. Suitable non-oxidizing biocides include, for example other
quaternary ammonium compounds (e.g., quaternary amine compounds and
cocodiamine), halogenated compounds (e.g., bronopol and 2-2-dibromo-3-
nitrilopropionamide (DBNPA)), sulfur compounds (e.g., carbamates, and
metronidazole), and quaternary phosphonium salts (e.g.,
tetrakis(hydroxymethyl)phosphonium sulfate (THPS)). Suitable oxidizing
biocides
include, for example, sodium hypochlorite, trichloroisocyanuric acids,
dichloroisocyanuric acid, calcium hypochlorite, lithium hypochlorite,
chlorinated
hydantoins, stabilized sodium hypobromite, activated sodium bromide,
brominated
hydantoins, chlorine dioxide, ozone, and peroxides.
[0092] Suitable pH modifiers include, but are not limited to, alkali
hydroxides,
alkali carbonates, alkali bicarbonates, alkaline earth metal hydroxides,
alkaline
earth metal carbonates, alkaline earth metal bicarbonates and mixtures or
combinations thereof. Exemplary pH modifiers include NaOH, KOH, Ca(OH)2,
CaO, Na2CO3, KHCO3, K2CO3, NaHCO3, MgO, and Mg(OH)2.
[0093] Any antioxidant suitable in oilfield operations may be used.
Exemplary
antioxidants include but are not limited to sulfites, thiocyanates and
thiosulfates.
An antioxidant may be included in a composition in an amount of about 1 ppm to
about 1000 ppm on a weight basis.
[0094] The composition may also comprise one or more additional foaming
agents such as an additional anionic surfactant, a cationic surfactant, a
nonionic
surfactant, an amphoteric surfactant, or a zwitterionic surfactant. Such
additives
can be introduced into the well, wellbore or pipeline before, during or after
the
introduction of quaternary organosilane composition.
[0095] As described above, the composition of the present disclosure is
combined with a liquid in order to cause the liquid to foam. In one
embodiment,
the liquid is foamed in the presence of other fluids in order to separate the
liquid
from the other fluids. For instance, in one embodiment, the liquid can be
contained
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in a tubular structure comprising a gas well and the other fluid can comprise
natural gas. The amount of the composition added to the liquid can depend upon
numerous factors and circumstances. In one embodiment, the composition is
added to a liquid in an amount sufficient for the quaternary organosilane to
have a
concentration of at least about 250 ppm, such as at least about 500 ppm, such
as
at least about 750 ppm, such as at least about 1000 ppm, such as at least
about
1500 ppm, such as at least about 2000 ppm, such as at least about 3000 ppm,
such as at least about 4000 ppm. The concentration of the quaternary
organosilane in the liquid is generally less than about 10,000 ppm, such as
less
than about 5000 ppm, such as less than about 3000 ppm on a weight basis.
[0096] The present disclosure may be better understood with reference to
the
following example.
EXAMPLE
[0097] A series of tests were conducted to determine the foaming ability
and
foam stability of four foaming agents when combined with a hydrocarbon liquid.
Three of the foaming agents represent various foaming agents that have been
used in the past. The conventional foaming agents were compared to a foaming
agent in accordance with the present disclosure.
[0098] The following example demonstrates the ability of compositions made
according to the present disclosure to foam a hydrocarbon particularly
kerosene.
In this example, a composition containing a quaternary organosilane in
accordance
with the present disclosure was compared with compositions containing (1)
didecyldimethylammonium chloride, (2) a cocamine oxide surfactant, and (3) an
alkyl imidazoline surfactant, particularly a coco-substituted imidazoline.
[0099] The following test procedure was used. The quaternary organosilane
composition and the other foaming agent compositions were added to a one liter
graduated cylinder containing 200 mL of kerosene. Nitrogen was sparged into
the
kerosene in the graduated cylinder via a glass diffusion stone at a rate of
56.6 L/hr
(2 SCFH).
[00100] The quaternary organosilane composition and the other foaming agents
were added to the kerosene at a concentration of between 250 ppm to 1500 ppm
on a weight basis using a micropipet.
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[00101] The foam height represented the mL occupied by the foam after the
foam was formed. Foam height was observed for 5 minutes or for the required
time in order to meet maximum foam height. The half-life represents the time
it
takes a foam having an initial foam volume to decay by 50% of that original
foam
volume, e.g., if the initial foam volume is 500 mL as measured in a 1000 mL
graduated cylinder, then the half-life is the time is takes for the foam
volume to
reduce to a value of 250 mL
[00102] Foam half-life was measured at the time in which the foam collapsed to
half of its original volume. Testing was performed at room temperature 22 C.
The
materials used in the examples are as follows:
Material Description
Kerosene 100% Low odor Kerosene (CAS 64742-47-8)
Sample No. 1 72% 3-(trimethoxysily1) propyldimethyloctadecyl ammonium
chloride (CAS 27668-52-6) and 28% methanol
Sample No. 2 80% Didecyldimethylammonium chloride (CAS 7173-51-5),
10% water and 10% ethanol
Sample No. 3 N-alkyl(C12-C16) dimethylamine oxide containing primarily
cocamine oxide sold as Barlox 12 by Lonza, Inc.
Sample No. 4 Coco-substituted imidazoline sold as Amphoterge K-2 by
Lonza, Inc.
[00103] Sample No. 1 above is a milky liquid with 72% active. A 10% stock
solution was used to dose the material into the kerosene at the desired
concentration. The 10% stock solution was produced by combining 10% of
Sample No. 1 by weight with 90% by weight kerosene. Sample No. 1 was
observed to dissolve fully to form a 10% solution in kerosene. Sample No. 2 is
known to have solubility in kerosene of less than 1000 ppm. Sample No. 2 was
dosed directly to the foam cell kerosene sample. Sample Nos. 2 and 3 were also
formed into 10% by weight stock solutions in kerosene prior to being added to
the
foam cell kerosene samples at the desired concentrations. The following
results
were obtained:
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A.I. Max Foam Foam Foam
Material Dosage at Time Height Half-Life Observation
Kerosene --- 5 min 20 mL <2 sec Fast breaking
Alone foam
Sample No. 1 250 ppm 5 min 15 mL <2 sec Precipitation
500 ppm 2 min 80 mL <2 sec observed
min 30 mL after sitting
750 ppm 1.5 min 755 mL <5 sec over night
2.5 min 280 mL
5 min 80 mL
1000 ppm 1.5 min 880 mL 60 sec
2.5 min 480 mL
5 min 230 mL
1500 ppm 1.5 min 980 mL 90 sec
(max)
Sample No. 2 250 ppm 5 min 25 mL <2 sec Slightly Hazy
500 ppm 5 min 25 mL solution after
750 ppm 5 min 20 mL sitting
1000 ppm 5 min 20 mL overnight
1500 ppm 5 min 25 mL
Sample No. 3 0 ppm 5 min 10 mL <2 sec Fast breaking
250 ppm 5 min 10 mL < 2 sec foam
500 ppm 5 min 10 mL < 2 sec
750 ppm 5 min 10 mL < 2 sec
1000 ppm 5 min 10 mL < 2 sec
1500 ppm 5 min 10 mL < 2 sec
Sample No. 4 0 ppm 5 min 10 mL <2 sec Fast breaking
250 ppm 5 min 10 mL < 2 sec foam
500 ppm 5 min 10 mL < 2 sec
750 ppm 5 min 10 mL < 2 sec
1000 ppm 5 min 10 mL < 2 sec
1500 ppm 5 min 10 mL < 2 sec
[00104] Sample No. 1 appeared to be a self-dispersing composition in kerosene
in high concentrations. At 1500 ppm, the treated kerosene was observed to
contain a precipitate after sitting over night.
[00105] Although Sample No. 1 and Sample No. 2 are both quaternary
ammonium compounds, Sample No. 1 shows significantly higher foaming
performance in kerosene. Sample No. 1 had high foaming potential when dosed
at 750 to 1500 ppm in kerosene. The maximum foam height was reached early
(particularly at 1.5 minutes). In addition, the foam of Sample No. 1 dispersed
relatively quickly having a foam half-life of 60 seconds at 1000 ppm and
having a
foam half-life of 90 seconds at 1500 ppm. This result is particularly
advantageous.
For example, when combined with a hydrocarbon liquid in an oil or gas well,
the
foaming agent of the present disclosure will rapidly form a foam, allow the
foamed
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hydrocarbon liquid to reach the surface, and then the foam will rapidly
disperse
leaving a hydrocarbon liquid product that can be easily handled and processed.
[00106] In contrast, all of the other foaming agents (Sample No. 2, Sample No.
3, and Sample No. 4) were not capable of forming any substantial amounts of
foam when combined with the kerosene under the test conditions. Although the
foaming agents of Sample No. 2, Sample No. 3, and Sample No. 4 are capable of
forming a foam when combined with water, the foaming agents are not suited for
foaming hydrocarbon liquids.
[00107] These and other modifications and variations to the present invention
may be practiced by those of ordinary skill in the art, without departing from
the
spirit and scope of the present invention, which is more particularly set
forth in the
appended claims. In addition, it should be understood that aspects of the
various
embodiments may be interchanged either in whole or in part. Furthermore, those
of ordinary skill in the art will appreciate that the foregoing description is
by way of
example only, and is not intended to limit the invention so further described
in such
appended claims.
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