U.S. patent application number 12/822815 was filed with the patent office on 2011-12-29 for method for resolving emulsions in enhanced oil recovery operations.
Invention is credited to Duy T. Nguyen.
Application Number | 20110315604 12/822815 |
Document ID | / |
Family ID | 45351527 |
Filed Date | 2011-12-29 |
United States Patent
Application |
20110315604 |
Kind Code |
A1 |
Nguyen; Duy T. |
December 29, 2011 |
METHOD FOR RESOLVING EMULSIONS IN ENHANCED OIL RECOVERY
OPERATIONS
Abstract
Disclosed and claimed is a method of demulsifying an emulsion
comprising water and oil. The method comprises adding an effective
amount of a composition comprising at least one substantially fully
quaternized ammonium adduct of polyephalohydrin that has a
molecular weight from about 500 Da to about 2,500 Da.
Inventors: |
Nguyen; Duy T.; (Houston,
TX) |
Family ID: |
45351527 |
Appl. No.: |
12/822815 |
Filed: |
June 24, 2010 |
Current U.S.
Class: |
208/188 |
Current CPC
Class: |
C10G 33/04 20130101;
C09K 8/588 20130101; B01D 17/047 20130101 |
Class at
Publication: |
208/188 |
International
Class: |
C10G 33/04 20060101
C10G033/04 |
Claims
1. A method of demulsifying an emulsion comprising water and oil,
the method comprising adding an effective amount of a composition
comprising at least one substantially fully quaternized ammonium
adduct of polyepihalohydrin and substantially free of zinc
chloride, wherein said adduct(s) have a weight average molecular
weight from about 500 Da to about 2,500 Da.
2. The method of claim 1, wherein the quaternary ammonium adduct(s)
of polyepihalohydrin are fully quaternized.
3. The method of claim 1, wherein the composition is free of zinc
chloride.
4. The method of claim 1, wherein the substantially fully
quaternized ammonium adduct(s) of polyepihalohydrin is formed by
reacting a polyepihalohydrin with trimethylamine or triethylamine
at a molar ratio of 1:1.1 and at temperatures from about
100.degree. C. to 150.degree. C.
5. The method of claim 1, wherein the quaternary ammonium adduct(s)
of polyepihalohydrin are prepared in the presence of a boron
trifluoride catalyst.
6. The method of claim 1, wherein the quaternary ammonium adduct(s)
of polyepihalohydrin have general formula: ##STR00002## wherein
each R is independently methyl or ethyl and z ranges from about 4
to about 22
7. The method of claim 6, wherein X is selected from the group
consisting of: fluoride, chloride, bromide, iodide, astatide, and
any combination thereof.
8. The method of claim 6, wherein X is chloride.
9. The method of claim 6, wherein z is 6.
10. The method of claim 6, wherein at least one R is methyl.
11. The method of claim 6, wherein each R is methyl.
12. The method of claim 1, wherein the composition comprises from
about 30 to about 90 wt % active material.
13. The method of claim 1, wherein the composition further
comprises an organic solvent, water, and any combination
thereof.
14. The method of claim 11, wherein the organic solvent comprises
an alcohol, an ether, an aromatic compound, or any combination
thereof.
15. The method of claim 1, wherein the effective amount of the
composition comprises from about 50 ppm to about 20,000 ppm, based
on actives and total emulsion volume.
16. The method of claim 1, further comprising adding a component to
the emulsion, wherein the component is selected from the group
consisting of a polymeric nonionic surfactant, a polymeric cationic
surfactant, a betaine, and any combination thereof.
17. The method of claim 16, wherein the component and the
composition are added about simultaneously to the emulsion.
18. The method of claim 1, wherein the emulsion is a produced
emulsion from an enhanced oil recovery operation.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to the field of enhanced
oil production and recovery. More specifically, the invention
relates to the field of recovery of crude oil from produced
emulsions of surfactant-polymer enhanced oil recovery floods. The
invention has particular relevance to the use of quaternary
ammonium salt adducts of polyepihalohydrin polymers to resolve such
emulsions.
BACKGROUND OF THE INVENTION
[0002] The production of crude oil from reservoirs typically
results in significant quantities of non-produced crude oil
remaining in the reservoir. After primary oil recovery has been
performed, secondary recovery (typically involving water
injection), is commonly used to produce trapped oil. Frequently,
much oil remains in the reservoir and tertiary recovery operations
have been developed to produce the remaining oil. Most tertiary
recovery methods for recovering such remaining crude oil include
surfactant-polymer enhanced oil recovery floods, such as injecting
a combination of surfactants and polymers in brine solutions into
the reservoir. Other methods for enhanced oil recovery may include
gas injection, chemical injection, ultrasonic stimulation,
microbial injection, and thermal recovery. If the oil recovered
using enhanced oil recovery floods cannot be efficiently treated
(e.g., the emulsion broken into dry oil and clean water), then most
if not all oil producers will be reluctant to conduct chemical
floods in favor of other less aggressive and lower recovery
processes.
[0003] Results of such conventional methods include a produced
emulsion that typically contains crude oil, water, surfactant, and
polymer. Drawbacks include difficulties in separating the emulsion
into clean water and dry oil for efficient recovery of the crude
oil and proper disposal of the water in an environmentally safe
manner. Heat has been used to aid in resolving such emulsions but
is not economical due to the large amounts of water involved.
Solvent extraction is disclosed in U.S. Pat. No. 4,559,148, "Method
of Extracting and Reutilizing Surfactants from Emulsions," but is
also not practical due to the large capital investment and
flammable solvent handling issues.
[0004] Consequently, there is a need for improved methods of
resolving crude oil and water emulsions. Additional needs include
improved methods for demulsifying the produced emulsion to produce
a clean separation of the crude oil and water.
BRIEF SUMMARY OF THE INVENTION
[0005] Accordingly, the present invention provides a method for
resolving emulsions produced through an enhanced oil recovery
process. In an aspect, the method includes adding a composition
comprising at least one quaternary ammonium adduct of
polyepihalohydrin.
[0006] In an aspect, this invention meets the previously unmet need
of efficiently demulsifying an emulsion comprising water and oil.
The emulsions applicable in the method of the invention are
preferably derived from an enhanced oil recovery process, though
the method has equal applicability to any emulsions encountered in
the art.
[0007] It is an advantage of the invention to provide a novel
method of resolving an emulsion comprising oil and water.
[0008] It is another advantage of the invention to provide a novel
method of efficiently resolving an emulsion comprising oil and
water that was derived from an enhanced oil recovery process.
[0009] It is yet another advantage of the invention to provide a
novel method of resolving an emulsion resulting from a chemical
enhanced oil recovery flood comprising oil and water to produce dry
oil and clean water.
[0010] 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
DETAILED DESCRIPTION OF THE INVENTIOIN
[0011] This invention comprises a method of treating an emulsion
comprising oil and water derived from an oil recovery process. A
preferred area of the method of the invention are emulsions derived
from enhanced oil recovery processes where oil remaining in a
reservoir after conventional recovery methods have been exhausted
is produced through, for example, a polymer-surfactant flood. It
should, however, be appreciated that the method of the invention
has equal application to emulsions derived from any conventional or
enhanced oil recovery operation. The objective of the present
invention is to provide a method of resolving emulsions resulting
in dry oil and clean water.
[0012] The emulsion produced from an enhanced oil recovery process
is typically stabilized with surfactants and polymers. The method
of the invention is applicable to any enhanced or tertiary oil
recovery process. Exemplary methods of producing oil through such
enhanced oil recovery processes are disclosed in U.S. Pat. Nos.
4,293,428, "Propoxylated Ethoxylated Surfactants and Method of
Recovering Oil Therewith" and 4,018,278, "Surfactant Oil Recovery
Process Usable in High Temperature Formations." U.S. Pat. No.
3,591,520 discloses the process of breaking an oil-in-water
emulsion with a blend of high molecular weight quaternary adducts
of polyepihalohydrin (MW>3000) and 10% zinc chloride at a ratio
of at least 2.5 to 1 of metal salt to adduct. U.S. Pat. No.
3,320,317 discloses the use of partial quaternary ammonium adducts
of epichlorohydrin having molecular weight from about 600 to about
100,000 as flocculating agents for improving the sedimentation of
sewage solids.
[0013] In the method of the invention, emulsions are treated by a
composition comprising low molecular weight (weight average
molecular weight from about 500 Da to about 2,500 Da) substantially
fully quaternized adducts of tertiary amines and polyepihalohydrin
(>99% quaternized) to demulsify emulsions produced, for example,
by surfactant-polymer enhanced oil recovery floods and recover dry
oil and clean water. In a preferred embodiment, zinc chloride is
substantially absent from the composition. The composition is more
preferably free of zinc chloride. In sour systems, zinc chloride
reacts with hydrogen sulfide presence in the crude oil to form zinc
sulfide which can cause stable emulsion (i.e., rag layer between
oil and water interface) and foul the separation vessels. High
molecular weight quaternary ammonium adducts of epihalohydrin and
partial quaternary ammonium adducts of epihalohydrin (particularly
epichlorohydrin) were found to be less effective (see examples
below) in the tested emulsions caused by chemical enhanced oil
recovery floods. In such embodiments, the produced emulsions
typically contain at least water, crude oil, surfactants, and
polymers. Addition of the composition 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. (See e.g., Z. Ruiquan et al.,
"Characterization and demulsification of produced liquid from weak
base ASP flooding," Colloids and Surfaces, Vol. 290, pgs 164-171,
(2006); U.S. Pat. Nos. 4,374,734 and 4,444,654).
[0014] In an embodiment, the composition of the invention includes
water soluble quaternary adducts of polyepihalohydrin having
molecular weights of from about 500 to 2,500 which have the general
formula:
##STR00001##
In the general formula, each R independently represents methyl or
ethyl and z ranges from about 4 to about 22. X is a halide selected
from fluoride, chloride, bromide, iodide, astatide, and any
combination thereof. In a preferred embodiment, X is chloride and z
is from 4 to 7. More preferably z is 6. In a further preferred
embodiment, X is chloride, z is 6, and at least one R is methyl.
More preferably, each R is methyl.
[0015] These materials may be prepared by any suitable method.
Generally, the materials are prepared by reacting a
polyepihalohydrin with trimethylamine or triethylamine at a molar
ratio of 1:1.1 at temperatures from about 100.degree. C. to
150.degree. C., preferably at a temperature of about 100.degree. C.
If the quaternizing amine is volatile such as trimethylamine, the
reaction is typically carried out in a closed vessel under the
pressure such as an autoclave. The molecular weight of the
polyepihalohydrin can be controlled by the epihalohydrin to water
ratio in the presence of boron trifluoride as a catalyst. A
preferred catalyst for preparation of the polyepihalohydrins of the
invention is boron trifluoride, rather than the more common
organoaluminum catalyst (See e.g., U.S. Pat. No. 3,591,520). The
main advantage of using the boron trifluoride catalyst is that a
smaller amount of catalyst is used.
[0016] The disclosed polyepihalohydrin composition may have any
desirable amount of active material. In an embodiment, the
composition has from about 30 wt % to about 90 wt % active
material. Alternatively, the composition has from about 30 wt % to
about 60 wt % or from about 40 wt % to about 70 wt %, and further
alternatively the composition has from about 50 wt % to about 90 wt
% active material. The composition is added to the emulsion in any
suitable amount.
[0017] Embodiments further include a composition having the
disclosed polyepihalohydrin and a solvent. The solvent may be any
solvent suitable, for example, for dissolving or suspending the
quaternary ammonium adducts of polyepihalohydrin. In embodiments,
the solvent is water, alcohol, an organic solvent, or any
combination thereof. The alcohol may include any alcohol suitable
as a solvent and for use with oil recovery operations. Without
limitation, examples of suitable alcohols include glycol, isopropyl
alcohol, methanol, butanol, or any combination thereof. According
to an embodiment, the organic solvent includes aromatic compounds,
either alone or in any combination with the foregoing. In an
embodiment, the aromatic compounds have a molecular weight from
about 70 to about 400, alternatively from about 100 to about 200.
Without limitation, examples of suitable aromatic compounds include
toluene, xylene, naphthalene, ethylbenzene, trimethylbenzene, and
heavy aromatic naphtha (HAN), other suitable aromatic compounds,
and any combination of the foregoing. It is to be understood that
the amount of quaternary ammonium adducts of polyepihalohydrin in
the composition in relation to the solvent may vary in some
embodiments depending upon factors such as temperature, time, and
type of surfactant. For instance, without limitation, a higher
ratio of a quaternary ammonium adduct of polyepihalohydrin to
solvent may be used if a faster reaction time is desired.
[0018] The composition may also be added to the emulsion in any
suitable amount. In an embodiment, the composition is added in an
amount from about 50 ppm to about 20,000 ppm, based on actives and
total emulsion volume. In alternative embodiments, from about 100
ppm to about 10,000 ppm of the surfactant, further alternatively
from about 200 ppm to about 10,000 ppm surfactant, and further
alternatively from about 200 ppm to about 500 ppm surfactant is
added to the emulsion, based on actives and total emulsion
volume.
[0019] In embodiments, the disclosed polyepihalohydrin composition
is used in conjunction with other surfactants or additives. These
other surfactants or additives may be added as part of the same
composition or as a separate composition and may be added
simultaneously or sequentially. For example, the composition may be
added to the produced emulsion with one or more additional
components selected from a cationic surfactant, a nonionic
surfactant, an amphoteric surfactant, or any combination
thereof.
[0020] Without limitation, the cationic surfactants include alkyl
ammonium halide surfactants. Representative, cationic surfactants
include any combination or at least one of an alkyl trimethyl
ammonium halide, an alkyl dimethyl benzyl ammonium halide, and one
or more imidazolinium halides. Molecular weights of such quaternary
surfactants are in the range of about 200 to about 700,
alternatively from about 250 to about 500. The alkyl trimethyl
ammonium halide has an average alkyl chain length of C.sub.6 to
C.sub.16, alternatively C.sub.6 to C.sub.10, and alternatively
C.sub.12 to C.sub.18, and further alternative of C.sub.8.
[0021] Without limitation, examples of suitable polymeric nonionic
surfactants include polysorbates, fatty alcohols such as cetyl
alcohol and oleyl alcohol, copolymers of polyethylene oxide,
copolymers of polypropylene oxide, alkyl polyglucosides such as
decyl maltoside, alkylphenol polyethylene oxide, alkyl polyethylene
oxide, and ethoxylated propoxylated alkyl phenol-formaldehyde resin
chemistry. The polymeric nonionic surfactant is typically dissolved
or suspended in a solvent. Any solvent suitable for dissolving or
suspending a polymeric nonionic surfactant may be used. Without
limitation, examples of suitable solvents include water, ether,
alcohol, toluene, xylene, heavy aromatic naphtha (HAN), other
suitable organic solvents, or any combination thereof. The alcohol
may include any alcohol suitable for use with oil recovery and for
dissolving the polymeric nonionic surfactant. In an embodiment, the
polymeric nonionic surfactant is dissolved or suspended in a
solvent.
[0022] Without limitation, amphoteric surfactants useful in the
composition of the invention include betaines, alkylamionpropionic
acids, N-acyl glycinates, or any combination thereof. Any suitable
betaine for use as a surfactant in the produced emulsion may be
used. Without limitation, examples of suitable betaines include
capryllcapramidopropyl betaine, cocobetaine, cocamidopropylbetaine,
octyl betaine, caprylamidopropyl betaine, or any combination
thereof. The N-acyl glycinate is preferably tallow dihydroxyethyl
glycinate.
[0023] In an embodiment, the composition and the one or more
additional components are added to the produced emulsion in a
weight ratio of composition to polymeric nonionic surfactant from
about 9:1, alternatively from about 1:1. In embodiments, the
composition and, for example, polymeric nonionic surfactant are
added about simultaneously (either as separate formulations or as
part of the same formulation) or sequentially to the produced
emulsion. Without being limited by theory, simultaneous addition to
the produced emulsion of the composition and a polymeric nonionic
surfactant generally provide improved quality of separated oil and
aqueous phases. For instance, the simultaneous addition to the
produced emulsion of the disclosed composition and water with a
polymeric nonionic surfactant dissolved in an organic solvent
improved the quality of the separated oil and aqueous phases.
[0024] 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
[0025] 9 grams of water (0.50 mole) was added to a 500 ml 3-neck
reactor flask, and then sparged with nitrogen for 15 minutes. 2 ml
of boron trifluoride was slowly added and the mixture was heated to
60.degree. C. When the temperature was reached 60.degree. C., the
heater was removed and 231.3 g of epichlorohydrin (2.5 mole) was
slowly added with stirring. This reaction was exorthemic and the
temperature was kept between 90 and 100.degree. C. with the use of
an ice bath. After complete addition of epichlorohydrin, the
reaction was held for another 1 hour at 90.degree. C., and then for
30 minutes at 110.degree. C. The reactor was then cooled to
40.degree. C. and the polyepichlorohydrin was transferred to an
autoclave for quarternization. About 361.22 grams of 45%
trimethylamine aqueous solution (2.75 mole of trimethyamine) was
added to polyepichlorohydrin. The blend was heated to 100.degree.
C. for 24 hours. The composition was clear without sediments. The
theoretical molecular weight is about 780 g/mole and this product
is named Composition A.
Example 2
[0026] Cocktails 1 and 2 as shown in Table 1 are fluids that were
injected into the reservoir to enhance oil recovery. The emulsion
was produced in the lab by mixing either Cocktails 1 or 2 with the
oil at 90:10 or 50:50 by weight, respectively, under a high shear
via the Silverson L4RT Mixer at 5,000 rpm for 2 minutes. The
produced emulsion was then subjected to the described testing.
Cocktails 1 and 2 contained a very low concentration of the
surfactant that was used to achieve ultra low interfacial tension
between the trapped oil and the injection fluid/formation water.
The ultra low interfacial tension also allowed the alkali present
in the injection fluid to penetrate deeply into the formation and
contact the trapped oil globules. The alkali present in the fluids
(e.g., Na.sub.2CO.sub.3) then reacted with the acidic components in
the crude oil to form additional surfactant in-situ to continuously
provide ultra low interfacial tension and free the trapped oil. In
the alkaline surfactant polymer ("ASP") Process, polymer present in
the injection fluid was used to increase the viscosity of the
injection fluid, minimize channeling, and provide mobility control.
These surfactant and polymer molecules have a tendency to adsorb at
the oil droplet, thereby, stabilizing the emulsions.
[0027] The tests that produced the data in Tables 2 and 4 were
conducted in graduated six ounce prescription bottles to allow for
rapid water drop readings. All bottles used 100 ml of emulsion.
After pouring the emulsion followed by chemical addition, the
bottles were allowed to reach the desired temperature via a water
bath. Upon reaching the desired temperature, the samples were
shaken via a mechanical shaker and then returned to the water bath.
Water drop readings were recorded in millimeters. The values were
also used to gauge emulsion stability, where a faster water drop
indicated lower emulsion stability. As can be seen in Table 2, the
present invention is very effective at resolving the emulsion.
Conventional demulsifiers such as ethoxylated propoxylated alkyl
phenol-formaldehyde resins and alkylphenol polyethylene oxide were
found not to be effective under the tested experimental conditions.
Also, cationic surfactant such as alkyldimethylbenzyl ammonium
chloride required a much higher dosage (7,000 ppm) as compared to
3,000 ppm for the tested composition of the present invention
(i.e., Composition A).
TABLE-US-00001 TABLE 1 Water chemistry for ASP flood Species
Cocktail 1 Cocktail 2 NaCl (g/L) 3.115 3.115 CaCl.sub.2.cndot.2H2O
(g/L) 0.096 0.096 MgCl.sub.2.cndot.6H2O (g/L) 0.093 0.093
NaHCO.sub.3 (g/L) 1.310 1.310 KCl (g/L) 0.054 0.054
Na.sub.2SO.sub.4 (g/L) 0.236 0.236 Surfactant A, ppm 1,500 --
Surfactant B, ppm 1,500 -- Surfactant C, ppm -- 1,500 Surfactant D,
ppm -- 1,500 Diethylene glycol monobutyl 10,000 10,000 ether
(DGBE), ppm Na.sub.2CO.sub.3, ppm 10,000 10,000 Polyacrylamide, ppm
1,500 1,500
[0028] The demulsification was performed at 60.degree. C. using
Composition A as described in Example 1.
TABLE-US-00002 TABLE 2 Bottle test results of demulsification of an
Alkaline Surfactant Polymer (ASP) process Water Drop, (ml per 100
ml emulsion) ASP Dose Over- solution Oil Cut (ppm) 30 min 1 hr 2
hrs 4 hrs night Cocktail 1 10% Oil Cut 1,000 90 90 90 90 90 2,000
90 90 90 90 90 3,000 90 90 90 90 90 4,000 90 90 90 90 90 50% Oil
Cut 500 0 0 18E* 30E 30E 1,000 0 20 40 42 45 2,000 5 38 42 43 45
3,000 40 42 42 42 45 4,000 49 49 49 49 49 Cocktail 2 10% Oil Cut
500 92 90 90 90 90 1,000 92 90 90 90 90 2,000 91 90 90 90 90 50%
Oil Cut 1,000 0 0 0 0 30E 2,000 42 43 43 45 45 3,000 46 45 46 46 45
4,000 46 46 46 46 46 5,000 47 46 46 46 46 Untreated 10% Oil Cut 0 0
0 78E -- 9 *Water drop number with an "E" designation indicates the
water phase is oil-in-water emulsion (dirty water)
TABLE-US-00003 TABLE 3 Water chemistry for Surfactant Flood Species
Amount NaCl (g/L) 4.81 CaCl.sub.2.cndot.2H.sub.2O (g/L) 1.00
MgCl.sub.2.cndot.6H.sub.2O (g/L) 2.01 NaHCO.sub.3 (g/L) 3.99
Na.sub.2SO.sub.4 (g/L) 0.13 Petrostep S13D 5,000 (anionic
surfactant) (ppm) (84.32% active)
[0029] Table 3 lists the injection fluid constituents for the
composition used in the surfactant flood. The emulsion was produced
in the lab by mixing the injection fluid with the oil at 75:25
wt/wt, respectively, by shaking the bottle containg the mixture
mechanically for 10 minutes. The demulsifier was added to the above
emulsion and the bottle was again shaken for 2 minutes. The
demulsification was performed at 25.degree. C. using Composition A
and alkyldimethylbenzyl ammonium chloride using the testing method
described previously. In the test results presented in Table 4, oil
drop readings were recorded (as opposed to water drop readings
above) and were converted to the percentage of oil content. As can
be seen in Table 4, the present invention (e.g., Composition A)
outperformed the alkyldimethylbenzyl ammonium chloride (Composition
B) as indicated by a higher value for oil drop and much cleaner
water and also yielded a dry oil as indicated by small values of
bottom sediment or settlings (BS) and slug. The calculations and
definitions of these values are discussed below.
[0030] Following the water drop readings, the resolved or partially
resolved oil from each bottle was analyzed for water content. Using
a syringe with a needle, a small portion of the oil (about 6 ml)
was withdrawn. This aliquot of oil was added to a graduated API
centrifuge tube containing an equal volume of an aromatic solvent
and the contents were shaken by hand. Following centrifugation, the
percent residual emulsion, typically referred to BS, was noted for
each bottle. After recording BS values, alkyl sulfonate surfactant
(a chemical known to resolve the remaining emulsion) was added to
the centrifuge tube. Such chemicals are generally called "slugging
or knockout chemicals" and are typically low molecular weight
sulfonate-based materials. After slugging, the tube was again
shaken and centrifuged as previously described. The BS was thus
completely eliminated and only water remained in the bottom part of
the tube. The slug grindout number is reported as a percentage.
Smaller values of BS and slug indicate drier oil.
TABLE-US-00004 TABLE 4 Bottle test results of demulsification of a
surfactant flood emulsion with 25% oil cut Oil drop, % Thief
Grindout Treatment ppm 0.5 hr 1 hr 2 hr 4 hr 20 hr BS Slug
Untreated 0 0 8 16 52 72 15.2 6.0 Comp. A 2,000 100* 100 100 100
100 0.8 0.8 Comp. B 2,000 76** 84** 84** 84** 84** 0.8 0.8 *Clean
water **Dirty water
[0031] Table 4 lists an example of the injection fluid used for
surfactant-polymer flood (SP). The procedures for making the
emulsion and demulsification were described previously. Petrostep
is available from Stepan Company located in Northfield, Ill. and
Flopaam is available from SNF Floerger located in Andrezieux,
France (trademarks are property of the respective owners).
TABLE-US-00005 TABLE 4 Produced Brine Formulations to make 100 g
Brine for Surfactant-Polymer Flood brine NaCl (grams) 1.0
CaCl.sub.2.cndot.2H.sub.2O (grams) 0.1834 (Ca++, ppm) 500 FLOPAAM
.RTM. 3330S 0.12 (grams), 8 MM MW HPAM PETROSTEP .RTM. S-1 0.9458
(15.86% active; grams*) PETROSTEP .RTM. S-2 0.2223 (22.49% active;
grams*) Iso-butyl alcohol (R-3041; grams) 0.4 *weight of
surfactants as received
[0032] Table 5 shows the demulsification results conducted at
25.degree. C. In this Table, Compositions C, D, and E have the same
chemistry as Composition A (see Example 1) but different molecular
weights. The theoretical molecular weights for Compostions A, C, D,
and E are 780 g/mole, 2,300 g/mole, 1,500 g/mole, 320 g/mole,
respectively. Composition F is a pyridinium benzyl quat and
Composition G is a high molecular weight
polydiallyldimethylammonium chloride-polyacrylic acid copolymer.
Compositions A, D, and E broke the emulsion quickly (15 minutes),
gave clean water after the emulsion was resolved, and produced dry
oil. Other compostions took longer to break the emulsion, gave
dirty water or wet oil.
TABLE-US-00006 TABLE 5 Bottle test results of demulsification of a
surfactant-polymer flood emulsion with 30% oil cut. Unless
otherwise noted, the water separated from the emulsion was clear
and clean ppm Water drop (ml/100 ml emulsion) Thief Grindout
Product Actives 15 min 1 hr 2 hr 3 hr B.S Slug Untreated 0 20* 50*
60* 60* 28 34 Comp. A 200 65 69 69 70 0.6 0.6 Comp. B 210 68** 68**
70** 70** 0.4 0.4 Comp. C 200 65** 69 69 69 0.8 0.8 Comp. D 200
66** 69 69 70 0.8 0.8 Comp. E 200 20* 40* 60* 60** 13 24 Comp. F
200 65** 65** 68* 65* 0.6 0.2 Comp. G 210 10* 39* 60* 62** 11 25
*the water is dirty and rag layer (emulsion at the oil/water
interface) is present **the water is dirty but no rag layer is
formed
[0033] 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 are 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.
[0034] Any ranges given either in absolute terms or in approximate
terms are 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.
[0035] Furthermore, the invention encompasses any and all possible
combination 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. It is therefore intended that such changes and
modifications be covered by the appended claims.
* * * * *