POLYEP1HALOHYDRINREVERSE EMULSION BREAKERS
FIELD OF THE INVENTION
This invention relates generally to emulsion breaker compositions and methods for
resolving emulsions of water and oil. More particularly, the invention relates to structurally
modified polyepihalohydrins for resolving emulsions of water and oil. This invention has
particular relevance to branched and linear polyepihalohydrins and its polyelcctrolytes for
resolving oil-in-water emulsions and complex water external emulsions.
BACKGROUND OF THE INVENTION
Crude oil produced from geological formations contains various amounts of water. Water
and crude oil are naturally non-miscible. When naturally occurring interfacial active compounds
are present, however, these compounds can aggregate on the water and oil interface and cause oil
droplets to disperse in the water phase. Such water external, oil internal two phase systems are
commonly referred as reverse crude oil emulsions and can be quite stable. During crude oil
lifting through production tubes, the water and oil encounters an increased mixing energy from
rapid flow through chokes and bends. This additional mixing energy can further emulsify the
water and oil. The presence of crude oil in water can interfere with water treatment and/or water
re-injection systems. In particular, oil-free water is required for applications where water is
discharged into the environment, such as overboard water on offshore platforms, or is used in
steam generation, such as steam assisted gravity drainage.
Commonly used reverse emulsion-breaking chemicals, or water clarifiers, include the
following: tridithiocarbamic acids (U.S. Patent No, 5,1 52,927); dithiocarbamic salts (U.S. Patent
No. 5,247,087); dimethylaminoethyl acrylate methyl chloride and/or benzyl chloride quaternary
salts (U.S. Patent No. 5,643,460); polymeric quaternary ammonium betaines (U.S. Patent No.
3,929,635); and metal salts (zinc chloride, aluminum chloride). Polymeric quaternary ammonium
salts and copolymers of acrylic acid and acrylamide have also been used. These compounds,
however, may not provide satisfactory performance in all instances. In particular, in extremely
cold weather (e.g., -40°C and below) various problems are known. These active ingredients are
typically viscous and require a suitable solvent to reduce the viscosity of the reverse emulsion
breaker blend.
A main challenge in oilfield production is the resolution of oil-in-water emulsions,
otherwise known as reverse emulsions. Many reverse emulsion breakers also have a small
window of treatment dosages, which makes it challenging and difficult to properly control
resolution. Complex or multiple emulsions typically require both a reverse and a standard
emulsion breaker to aid in its resolution into clean water and dry oil. These two products
traditionally are incompatible, so each is typically injected separately.
There thus exists an ongoing need for new, economical and effective chemicals and
processes for resolving reverse emulsions and complex emulsions into the component parts of
water and oil.
BRIEF SUMMARY OF THE INVENTION
This invention accordingly provides a reverse emulsion breaker composition for resolving
water external emulsions of water and oil. In an aspect, the composition comprises an effective
amount of one or more polyepihalohydrins. In another aspect, one or more of the
polyepihalohydrins is a polyelectrolyte. In a method of resolving a reverse emulsion or complex
water external emulsion of water and oil, the invention comprises adding an effective amount of
one or more polyepihalohydrins, polyelectrolytes thereof, and any combination thereof.
It is an advantage of the invention to provide a novel demulsifier for resolving oil-inwater
emulsions related to petroleum applications.
It is a further advantage of the invention to provide novel demulsifiers that have superior
performance and are much more cost effective than those currently known in the art.
It is yet another advantage of the invention to provide a novel demulsifier for resolving
oil-in-water emulsions caused by surfactant injection related to enhanced oil recovery.
A further advantage of the invention is to provide a manufacturing advantage of easier
temperature control due to a greater mass of material to absorb the heat generated from the
reaction thus increasing safety.
An additional advantage of the invention is to provide a manufacturing advantage that
allows for the use of less epihalohydrin per batch due to a higher molecular weight glycerol
initiator.
The foregoing has outlined rather broadly the features and technical advantages of the
present invention in order that the detailed description of the invention that follows may be better
understood. Additional features and advantages of the invention will be described hereinafter
that form the subject of the claims of the invention. It should be appreciated by those skilled in
the art that the conception and the specific embodiments disclosed may be readily utilized as a
basis for modifying or designing other embodiments for carrying out the same purposes of the
present invention. It should also be realized by those skilled in the art that such equivalent
embodiments do not depart from the spirit and scope of the invention as set forth in the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates the general structure of the polyepihalohydrin compounds of the
invention.
Figure 2 illustrates the general structure of quaternized and branched polyepihalohydrin
compounds of the invention.
Figure 3 illustrates an embodiment for synthesis of branched polyepichlorohydrin.
Figure 4 illustrates an embodiment for the quaternization of branched
polyepichlorohydrin .
DETAILED DESCRIPTION OF THE INVENTION
The term "reverse emulsion breaker" as used herein refers to a class of chemicals used to
aid the separation of emulsions (including, simple emulsion of oil-in-water, and
multiple/complex emulsions such as waler-in-oil-in-water). Chemicals used to treat oil-in-water
emulsions are also commonly referred to as water clarifiers. They are commonly used in the
processing of crude oil, which is typically produced along with significant quantities of water. In
many instances the crude oil may be dispersed or emulsified in the water phase and must be
removed from the water prior to the re-injection, processing, or discharge of the water.
In an embodiment, the present invention relates to a reverse emulsion breaker
composition comprising one or more polyepihalohydrins and a method of using the composition
for resolving emulsions of water and oil. FIG 1 illustrates the general structure of such polymers
and FIG 2 illustrates an embodiment where the polymers are quaternized and branched. In FIG
1, X is a leaving group, such as chloride, bromide, iodide, trifluoromethylsulfonate,
toluenesulfonate, methylsulfonate, the like, and combinations thereof. The leaving group is
preferably chloride, bromide, iodide, or a combination thereof. The acid is a Lewis of Bronsted
Acid, preferably BF3 and/or ALMe3. yl, y2, and y3 independently range from about 2 to about
20. In a preferred embodiment, yl, y2, and y3 independently range from about 3 to about 15. In
a more preferred embodiment, yl, y2, and y3 independently range from about 5 to about 10.
Higher epihalohydrin to glycerol ratios, for example, lead to higher y values. For example, a 5:1
epi:alcohol (e.g., glycerol) ratio, y = 2-3, for 10:1 ratio y = 6-7, for 20:1 y = 14-15, etc. In FTG 2,
X is a leaving group as described above. R1, R2, and R 3 are independently any alkyl or aryl
group or hydrogen. Preferred are methyl and/or ethyl.
"Alkyl" refers means a monovalent group derived from a straight or branched chain
saturated hydrocarbon by the removal of a single hydrogen atom. Representative alkyl groups
include methyl, ethyl, n- and iso-propyl, cetyl, and the like. Preferred alkyls are methyl and
ethyl,
"Aryl" refers an aromatic monocyclic or multicyclic ring system of about 6 to about 10
carbon atoms. The aryl is optionally substituted with one or more C1 -C 20 alkyl, alkoxy or
haloalkyl groups. Representative aryl groups include phenyl or naphthyl, or substituted phenyl
or substituted naphthyl.
In a further embodiment, the composition comprises at least one polyepihalohydrm, at
least one polyelectrolyte thereof, and any combination thereof.
According to an embodiment, the disclosed reverse emulsion breakers may be used alone
or in combination with any of a number of other emulsion breakers or demulsifiers known in the
art. Typical demulsifiers for breaking crude oil emulsions that may have utility in the
compositions herein are described, for example, in U.S. Patent Nos. 2,470,829; 2,944,978;
3,576,740; 5,152,927; and 5,643,460. Other reverse emulsion breakers that may have utility in
conjunction with the disclosed composition are disclosed in U.S. Patent Nos. 5,032,085,
"Reverse Emulsion Breaking Method Using Amine Containing Polymers" and 5,643,460,
"Method for Separating Oil from Water in Petroleum Production."
In alternative embodiments, the disclosed composition for the reverse emulsion breaker
generally depends upon the emulsion properties of the produced fluids. More specifically, the
reverse emulsion breaker composition is formed from an effective amount of one or more
polyepihalohydrins. The composition may contain any amount of the composition sufficient to
produce a water clarification. The reverse emulsion breaker composition can be made in a
variety of concentrations including between broadly trace to about 100% or about 1% to about
99% by weight of the composition or between about 10% and about 90% by weight of the
composition. More specifically, the reverse emulsion breaker can be added in an amount equal
to between about 20% and about 80% by weight of the composition or, about 40% and about
70% by weight of the reverse emulsion breaker composition. More preferably, the reverse
emulsion breaker is added in an amount equal to between about 25% and about 50% by weight of
the reverse emulsion breaker composition.
In an alternative embodiment, other solvents may be included with the polyepihalohydrin
reverse emulsion breaker of the invention whereby the solvent can be added in an amount
ranging between about 1% and about 10% by total weight of the formulation composition.
Again, broadly, the reverse emulsion breaker composition can include an amount of the
polyepihalohydrin ranging between trace or about 1% and up to about 99% or 100% by weight of
the demulsifier composition. Typical solvents comprise water and/or low molecular weight
alcohols.
The amount of the reverse emulsion breaker composition used depends on the particular
water external emulsion being treated. In general, the effective amount of reverse emulsion
breaker composition ranges from between about 1 ppm to about 5,000 ppm actives based on the
total emulsion volume. More preferably, the dosage range is from about 1 ppm to about 1,000
ppm actives based on total emulsion volume. In another embodiment, the dosage is from about
10 ppm to about 1,000 ppm actives based on total emulsion volume.
Introducing the reverse emulsion breaker composition into the emulsion can be
accomplished by any suitable method. For example, the composition may be injected into the
crude oil at the well-head, or injected into the crude oil up-stream of the water separation vessels
(such as free water knock-out or heat treater vessels). The reverse emulsion breaker may also be
injected into the oil contaminated water upstream of the water floatation cells or upstream of
skim tanks. The reverse emulsion breaker composition may be injected continuously or in batch
fashion. The injection step is preferably accomplished using electric or gas pumps, but any
suitable pumping device may be used.
The treated water external crude oil emulsion is then allowed to separate into distinct
layers of water and oil. Once separation into distinct layers of water and oil has been effected,
various means known in the art can be utilized for withdrawing the free water and separating
crude oil. In a typical process for water clarification of produced water, a reservoir is provided to
hold the composition of the invention in either diluted or undiluted form adjacent to the point of
chemical injection. The role of the reverse emulsion breaker is usually to clean and oil free water
for discharge. It should be appreciated that the invention has equal application for all processes
in the petroleum industry.
Preferred polyepihalohydrins of the invention include polyepichlorohydrin,
polyepibromohydrin, polyepiiodohydrin, the like, and combinations thereof. The molecular
weight range of these polymers is generally from about 400 to about 20,000 Mn (number average
molecular weight),
In synthesizing the polyepihalohydrins of the invention, a wide range of polyols with a
Lewis acid catalyst may be used to initiate the reaction as well as the alkoxylated (e.g.,
ethoxylated or propoxylated) analogs thereof. Representative polyols include trimethylol
propane, glycerol, polyglycerol, pentaerythritol, sorbitol, the like, and combinations thereof. In
alternative embodiments, any polyol known in the art ot equivalents may be used in to initiate the
synthesis reaction. Representative Lewis acids include alkyl aluminum compounds (e.g.,
triisobutyl aluminium, triethyl aluminum, diisobutyl aluminum chloride, monoisobutyl aluminum
chloride, and aluminum isoproylate), BF3, HPF 6, and SnCl4, the like, and combinations thereof.
In alternative embodiments, any Lewis acid known in the art or equivalents may be used in the
reaction sequence. Represenativc Bronsted acids include but are not limited to HCl, H2SO4,
HClO, HBr, or combinations thereof. In alternative embodiments, any Lewis or Bronsted acid
known in the art or equivalents thereof may be used in the reaction sequence.
A preferred polyepichlorohydrin for use in the reverse emulsion breaker of the invention
is a quaternized, branched polyepichlorohydrin. Referring to FIG 3, polymerizing
epichlorohydrin in the presence of a polyol and a Lewis acid catalyst generates the preferred
branched polyepichlorohydrin of the invention. The molecular weight of the
polyepichlorohydrin is generally controlled by the ratio of epichlorohydrin to polyol in the
reactant mixture. By varying this ratio from about 5:1 to about 20:1, it is possible to produce
polymers with molecular weights ranging from about 400 to about 3,000 Mn.
In a second reaction step upon obtaining the branched polyepichlorohydrin, a primary,
secondary, and/or tertiary amine is used to yield the final polyelectrolyte, as shown in FIG 4.
Examples of these amines include ammonia, methylamine, trimethylamine, triethylamine,
dimethylamine, diisopropylethylamine, piperadine, pyridine, the like, and combinations thereof.
Additionally, polyamines may also be used in this step to generate crossl inking and higher
molecular weight polyelectrolytes. Representative polyamines include ethylcndiamine,
diethylenetriamine, tetramethylethylenediamine, tetraethylenepentaamine, the like, and
combinations thereof.
In an embodiment, at any time prior to functionalization the central core of the polyol has
3 or more accessible alcohol functional groups as in general formula (1) below.
Where, R1 and R2 are selected from H, alkyl, OH, CH2OH, C4H9O4, sorbitol, other sugar
alcohols, and the like. R 3 is selected from OH, CH2OH, C4H 9O4 , sorbitol, other sugar alcohols,
polyclycerol, polyetheyleneoxide, polypropyleneoxide, and the like.
In an embodiment, the polyol is reacted as shown below, where R4 is shown as general
formula (2) below. X ranges from about 2 to about 20, preferably from about 3 to about 15, and
more preferably from about 5 to about 10.
In an embodiment, a glycerol core is reacted where R4 is shown as general formula (3)
below. The product of this reaction is shown as general formula (4) below, where x, y, and z
independently ranges from about 2 to about 20, preferably from about 3 to about 15, and more
preferably from about 5 to about 10, again dependent on the epi to alcohol ratio.
In embodiments, the reverse emulsion breaker composition of the invention is used to
separate emulsions produced by alkali-suriactant-polymer or surfactant-polymer enhanced oil
recovery floods. In such embodiments, the produced emulsions typically contain at least water,
crude oil, surfactants, and polymers. Addition of the reverse emulsion breaker composition of
the invention to the produced emulsion separates the oil and water phases. In some
embodiments, the separation is a clean separation of oil and water. A clean separation generally
refers to dry oil with less than about 1% total sediment and water, a good interface with sharp
separation between oil and water, and clean water with less than about 300 parts per million
(ppm) residual oil. The composition is added to the emulsion by any suitable method. For
instance, examples of suitable methods include the methods disclosed in Z. Ruiquan et al.,
"Characterization and demulsification of produced liquid from weak base ASP flooding,"
Colloids and Surfaces, Vol. 290, pgs 164-171, (2006) and U.S. Patent Nos. 4,374,734 and
4,444,654.
In another embodiment, the reverse emulsion breaker composition of the invention may
have utility in stabilizing clays during fracturing of a subterranean reservoir. During the
fracturing of subterranean reservoirs, clays native to the reservoir will often swell when brought
into contact with injected water, lowering the efficiency of the fracturing process. Clay stabilizer
products are mixed with the fracturing fluid (e.g., water) prior to injection to prevent clay
swelling, thus enhancing the total efficiency of the fracturing process.
The foregoing may be better understood by reference to the following examples, which
are intended for illustrative purposes and are not intended to limit the scope of the invention.
Example 1
Reaction Scheme 1: To a 250 ml four-necked flask was added 16.8 g of
trimethylolpropane. The flask was purged with N2 and heated to 60 °C while stirring. One mL
of BF3-OEt2 was then added and 231.3 g of epichlorohydrin was added dropwise over the course
of an hour, maintaining the temperature between 85°C and 95°C. Once the addition was
completed, the resulting mixture was stirred at 95°C for one hour. The temperature was then
increased to 110°C and the mixture mixtured was sparged with N2 for one hour to yield the
trimethylolpropane/epichlorohydrin copolymer.
Reaction Scheme 2: To a 250 ml four-necked flask was added 33.5 g of
trimethylolpropane. The flask was purged with N2 and heated to 60 °C while stirring. One mL
of BF 3 -OE 2 was then added and 231.3 g of epichlorohydrin was added dropwise over the course
of an hour, maintaining the temperature between 85 °C and 95°C. Once the addition was
completed, the resulting mixture was stirred at 95 °C for one hour. The temperature was then
increased to 110 °C and the mixture mixtured was sparged with N2 for one hour to yield the
trimethylolpropane/epichlorohydrin copolymer.
Reaction Scheme 3: To a 250 ml four-necked flask was added 92.1 g of glycerol. The
flask was purged with N2 and heated to 60 °C while stirring. One mL of BF3·OEt2 was then
added and 231.3 g of epichlorohydrin was added dropwise over the course of an hour,
maintaining the temperature between 85 °C and 95°C. Once the addition was completed, the
resulting mixture was stirred at 95 °C for one hour. The temperature was then increased to 110
°C and the mixture mixtured was sparged with N2 for one hour to yield the
glycerol/epichlorohydrin copolymer.
Reaction Scheme 4: To a 500 mL hastclloy autoclave was added 50.3 g of
trimethylolpropane/epichlorohydrin copolymer from Reaction Scheme 1. 66.5 g of a 45%
aqueous solution of trimethylamine was then added to the autoclave and the autoclave was then
sealed. The mixture was then heated to 100 °C and stirred at this temperature for 24 hours. After
24 hours, the autoclave was flushed with N2 and cooled to room temperature to yield the
trimethylamine quaternary salt of the trimethylolpropane/epichlorohydrin copolymer.
Reaction Scheme 5: To a 500 mL hastelloy autoclave was added 49.2 g of
glycerol/epichlorohydrin copolymer from Reaction Scheme 1. 63.5 g of a 45% aqueous solution
of trimethylamine (TMA) was then added to the autoclave and the autoclave was then sealed.
The mixture was then heated to 100 °C and stirred at this temperature for 24 hours. After 24
hours, the autoclave was flushed with N2 and cooled to room temperature to yield the
trimethylamine quaternary salt of the glycerol/epichlorohydrin copolymer.
Example 2
This example illustrates the effectiveness of the reverse emulsion breaker of the invention
embodied in FIG 4. It can be seen in Table 1 that the quaternized branched polyepichlorohydrin
polyelectrolytes were found to yield cleaner water at lower treat rates than the traditionally used
chemicals. Moreover, differences were observed between the branched and linear
polyepichlorohydin (PECH) polyelectrolytes. Though both are effective reverse emulsion
breakers and within the scope of the invention, the branched version has the advantage of being
able to resolve the emulsion at a lower dose and provide cleaner water (Table 1, Samples 5 and
6) than there linear equivalents (Table I, Samples 3, 4, 7, and 8). The branched molecules
also found to be less viscous than their linear counterparts making them easier to handle.
Example 3
This example illustrates the effectiveness of the reverse emulsion breaker of the invention
with regard to resolving reverse emulsions stabilized by anionic surfactant polymers. The
reverse emulsion was generated by mixing 30 mL crude oil with 70 mL of an anionic surfactant
solution in prescription bottles. The bottles were then place on a mechanical shaker for 10
minutes. The resulting mixture was then treated with the indicated chemical and shaken for an
additional 3 minutes. The bottles were removed from the shaker and separation of the oil and
water was monitored along with the resultant oil and water quality. It can be seen in Tables 2a
and 2b that the branched polyepichlorohydrin quaternized molecules provided a faster water drop
than linear counterparts as well as cleaner water.

Example 4
This example illustrates the effectiveness of the invention as a clay stabilization agent.
The effectiveness of the chemicals were measured via capillary suction timer (CST) testing by
weighing 250g deionized water into a 500 mL plastic beaker. The mixture was then stirred at a
Variac reading of 40 using an overhead stirrer. The clay stabilizer candidate to be evaluated is
added (0.25 mL; lgpt) to the water while stirring at this stage. A 30g premixed clay (83/17 silica
flour/ sodium bentonite) was next added to the solution and stirred at 50 Variac for 1min The
stirring was stopped and the clay set aside for 5min to allow time to hydrate. At the end of this
interval the slurry is stirred at 40 Variac and 1cc portions of samples are withdrawn and syringed
in through the sample port of the CST instrument. The CST value is read out from the display
and recorded. Three such readings are taken consecutively and averaged out to report the CST
value for the particular clay stabilizer additive at the studied dosage. In general, the lower the
CST value the more effective the clay stabilization.
All of the compositions and methods disclosed and claimed herein can be made and
executed without undue experimentation in light of the present disclosure. While this invention
may be embodied in many different forms, there arc described in detail herein specific preferred
embodiments of the invention. The present disclosure is an exemplification of the principles of
the invention and is not intended to limit the invention to the particular embodiments illustrated.
Any ranges given either in absolute terms or in approximate terms arc intended to
encompass both, and any definitions used herein are intended to be clarifying and not limiting.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the
invention are approximations, the numerical values set forth in the specific examples are reported
as precisely as possible. Any numerical value, however, inherently contains certain errors
necessarily resulting from the standard deviation found in their respective testing measurements.
Moreover, all ranges disclosed herein are to be understood to encompass any and all subranges
(including all fractional and whole values) subsumed therein.
Furthermore, the invention encompasses any and all possible combinations of some or all
of the various embodiments described herein. Any and all patents, patent applications, scientific
papers, and other references cited in this application, as well as any references cited therein, are
hereby incorporated by reference in their entirety. It should also be understood that various
changes and modifications to the presently preferred embodiments described herein will be
apparent to those skilled in the art. Such changes and modifications can be made without
departing from the spirit and scope of the invention and without diminishing its intended
advantages. Tt is therefore intended that such changes and modifications be covered by the
appended claims.
CLAIMS
The claimed invention is:
1. A reverse emulsion breaker composition for resolving a water external emulsion of
water and oil, the composition comprising an effective amount at least one polyepihalohydrin.
2. The reverse emulsion breaker composition of Claim 1, wherein the at least one
polyepihalohydrin is a polyelectrolyte.
3. The reverse emulsion breaker composition of Claim 1, wherein the at least one
polyepihalohydrin comprises at least one selected from the group consisting of:
polyepichlorohydrin; polyepibromohydrin, polyepiiodohydrin, and any combination thereof.
4. The reverse emulsion breaker composition of Claim 1, wherein the at least one
polyepihalohydrin is branched.
5. The reverse emulsion breaker composition of Claim 1, wherein the at least one
polyepihalohydrin has the following structure:
wherein, X is selected from chloride, bromide, iodide, trifluoromelhylsulfonate,
toluenesulfonate, methylsulfonate, and combinations thereof;
wherein yl is from about 2 to about 20;
wherein y2 is from about 2 to about 20; and
wherein y3 is from about 2 to about 20.
6. The reverse emulsion breaker composition of Claim 1, wherein the at least
polyepihalohydrin has the following structure:
wherein R| is selected from alkyl or aryl or hydrogen;
wherein R2 is selected from alkyl or aryl or hydrogen;
wherein 1なis selected from alkyl or aryl or hydrogen;
wherein yl is from about 2 to about 20;
wherein y2 is from about 2 to about 20; and
wherein y3 is from about 2 to about 20.
7. The reverse emulsion breaker composition of Claim 1, wherein the at least
polyepihalohydrin has the following structure:
wherein y l is from about 2 to about 20;
wherein y2 is from about 2 to about 20; and
wherein y3 is from about 2 to about 20.
8. The reverse emulsion breaker composition of Claim 1, wherein the at least one
polyepihalohydrin has the following structure:
wherein y l is from about 2 to about 20;
wherein y2 is from about 2 to about 20; and
wherein y3 is from about 2 to about 20.
9. The reverse emulsion breaker composition of Claim 1, wherein the at least one
polyepihalohydrin is present from about trace to about 100 wt%.
10. The reverse emulsion breaker composition of Claim 1, further comprising at least
one solvent.
11. A method for resolving an emulsion of water and oil, the method comprising adding
an effective amount of the reverse emulsion breaker composition of Claim 1.
12. The method of Claim 11, wherein the oil is selected from the group consisting of:
crude oil, refined oil, bitumen, condensate, slop oil, distillates, fuels, brines, and mixtures thereof.
13. The method of Claim 11, further comprising adding from about 1 ppm to about 5,000
ppm of said composition based on actives and total emulsion volume.
14. The method of Claim 11, wherein the emulsion is a produced emulsion from an
alkali-surfactant-polymer or surfactant-polymer enhanced oil recovery flood.
15. A method for stabilizing clays during fracturing of a subterranean reservoir, the
method comprising adding an effective amount of the composition of Claim 1 into a fracturing
fluid introduced into the subterranean reservoir.