Note: Descriptions are shown in the official language in which they were submitted.
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SU~IM~RY OF THE INVENTION
According to the invention, micellar dispersions
suitable for the displacement of oil in formations, e.g. in
enhanced recovery operations or in well stimulation, are produced
from whole crude oils by the treatment wi~h sulfur trioxide.
The resul~ing product mixture (with or without optional removal
of a portion of the unsulfonated hydrocarbons and with or without
addition of cosurfactant) is neutralized with a monovalent base
to form directly a micellar dispersion comprising the sulfonated .
hydrocarbons, at least a portion of the unreacted hydrocarbons ~.
and water.
In one particular aspect the present invention provides
in a process for the recovery of oil from an oil-bearing sub-
terranean formation by injecting into said formation a micellar
dispersion comprised of petroleum sulfonate, hydrocarbon and
water; the improvement comprising (a) recovering crude oil; (b) ..
sulfonating the crude oil with sulfur trioxide to form a product
comprising petroleum sulfonic acid; (c) neutralizing said product .
with aqueous monovalent base to form a micellar dispersion com- ...
20. prised of petroleum sulfonate having an average equivalent weight
of about 350 to about 525; (d) injecting said micellar dispersion
into the formation to displace additional oil toward a production
well in fluid communication with the formation. ~;
Because the usual steps of refining crude oil to pro- .. `
vide a fractionated feedstock, removing sludge by-product from
the sulfonate, and mi~ing together the ingredients of the micellar
dispersion are all usually avoided by the invention, great .. ;~
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1 economic savings in both feedstock utilization and reduced cost
2 of operations can be achieved.
3 Further, by placing the simple apparatus of the invention
4 proximate to the oil reservoir being injected with the micellar
dispersion, both feedstock and product transportation savings
6 are also achieved.
7 BRIEF DESCRIPTION OF THE DRAWING
8 Figure 1 shows a preferred embodiment of the sulfonation
9 process of the present invention without use of reaction solvent.
DE~CRIPTION OF THE PREF~RRED EMBODIMENTS
11 Starting Materials:
12 Hydrocarbon Feed: It is an important aspect of the pre-
13 sent invention that whole crude oil or topped crude oil is sul-
14 fonated. Previous processes have sulforlated gas oils without
achieving the simplicity of the present invention. Crudes
16 which are particularly useful for the practice of the invention
17 are those which are relatively high in aromatic content but
18 lubricating oil base crudes (low aromatic content) are acceptable.
19 The crude oil may be substituted with non-interfering
substituents, e.g., NO3, C12, SO4, etc., but will preferably
21 be a hydrocarbon. Preferred crude oils are those with aromatic
22 portions having molecular weights in the range of from about 200
23 to about 1000, more preferably from about 300 to about 800, and
24 most preferably from about 350 to about 500. The aromatic
content of the crude oil is preferably from about 10 to about 95,
26 more preferably from about 20 to about 80, and most preferably
27 from about 25 to about 50 weight percent aromatics as defined
. . .
51~2~3
1 in American Petroleum Institute Project 60 Reports 4-7 entitled
2 "Characterization of Heavy Ends of Petroleum". Especially
3 preferred are crude oils wherein the aromatic portion has an
4 aliphatic/aromatic proton ratio of from about 3 to about 20,
more preferably from about 4 to about 18.
6 The "aliphatic to aromatic proton ratio" used in the
7 specification is measured on a carbon tetrachloride solution
8 of the sample using a 60MHz nuclear magnetic resonance
9 spectrometer. The basic technique has been described by
V. H. Luther and H. H. Oelert, Erdol and Kohle, 24, 216 (1971).
11 All those protons which resonate with a chemical shift between
12 0 and 5 ppm from the tetramethylsilane internal standard are
13 defined as aliphatic protons; those which have a chemical shift
14 between 8.2 and 5 ppm are defined as aromatic protons. Evidence
of polynuclear aromatics in crude oil is scattered throughout
16 the petroleum literature.
17 Topped crudes, e.g., those having a portion of the hydro-
18 carbons boiling below about 600F. removed, can be utilized in
19 place of the whole crude oil.
Reaction Solvent: The sulfonation of the crude oil feed-
21 stock is accomplished using SO3. Though not necessary, the SO3
22 can be diluted with a reaction solvent to promote a more even
23 sulfonation reaction, to solubilize sulfonic acids in unreacted
24 hydrocarbon, and to lower the viscosity of the overall reaction
products. Ethylene dichloride (EDC), trichloroethane, nitro-
26 benzene, nitropropane, and like solvents are useful for this
27 purpose. The reaction solvent aids in keeping the reaction
28 product stream homogeneous and fluid. Whether or not a reaction
29 solvent is used depends on the crude oil being sulfonated. Heavy
3o viscous crude oils often require a solvent; lighter, less vis-
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1 cous crudes can be sulfonated with or without a reaction solvent.
2 When using a reaction solvent, concentrations of solvent are
3 typically from about 0 to 20 lbs., more preferably from about 1
4 to 10 lbs., and most preferably from 3 to 8 lbs. of solvent/
lb. SO3. The reaction solvent can be added to either the crude
6 oil stream, the SO3 stream, or to both streams.
7 SO3 Diluent: Either separately or in conjunction with
8 a reaction solvent, the SO3 stream can be diluted with a liquid
g or gas, e.g., SO2, refined light paraffins~ crude oil light
ends, air, nitrogen, natural gas, or other dry gases; with a
ll weight ratio of diluent to SO3 of about 0 to about 10, more
12 preferably about 2 to about 9, and most preferably about 3 to
13 abou~ 8 lbs./lb. SO3.
14 The main purpose of the diluent is to dilute the SO3
in order to promote a more even sulfonation reaction, e.g. to
16 reduce the amount of tri- and higher sulfonates produced.
17 While the SO3 diluent will not ordinarily solubilize the
18 sulfonates in the unreacted hydrocarbons, it has the addi-
19 tional advantage of lowering the viscosity of the reaction
products.
21 Sulfonation Additives: To optimize oil recovery it is
22 preferable though not absolutely necessary to add one or a
23 mixture of sulfonation additives. These additives may be
24 used either in conjunction with or in the absence of either
the aforementioned diluents or solvents. Such sulfonation
26 additives are preferably aromatic hydrocarbons, olefinic hydro-
27 carbons, or oxygenated hydrocarbons, and preferably have
28 molecular weights in the range of from about 200 to about lO00,
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1 or more preferably from about 300 to about 800, and most
2 preferably from about 350 to about 500. The sulfonation addi-
3 tives will be used in amounts of from about 0 to 20, more
4 preferably from about 2 to about 15, and most preferably from
about 4 to about 10 pounds of sulfonation additive per 100
6 pounds of crude oil (or topped crude oil) employed as feed to
7 the reactions of the invention.
8 The sulfonation additives can conveniently be incor-
9 porated into the crude oil feedstocks before the crude oil
feedstock is sulfonated. Thereafter, normal sulfonation
11 reaction procedures are followed and the sulfonation additives
12 themselves are generally sulfonated (or sulfated, in the case
13 of oxygenated hydrocarbons), and exit with the remaining
14 components of the micellar dispersion.
Sulfur Trioxide: The sulfur trioxide useful with the
16 present invention can be of the usual commercial purity
17 though high purity or relatively crude materials may be used
18 in specialized circumstances where warranted by the desired
19 products. The sulfur trioxide should be preferably sub-
stantially anhydrous and should be free from substantial
21 quantities of impurities which would cause deleterious side
22 reactions.
23 From about 5 to about 40, more preferably from about 7
24 to about 30, and most preferably from about 8 to about 20 lb.
SO3 per 100 lb. of unsulfonated crude oil will be fed to the
26 reactor zone.
27 Reaction Catalyst: While no catalyst will generally be
28 employed with the present invention, known sulfonation catalysts
29 can be employed where desired.
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1 Reaction Temperature: While not narrow~y critical, the
2 temperature in the reaction æone will generally be in the
3 range of from about 80 to about 250, more preferably from
4 about 100 to about 200, and most preferably from about 130
to about 180F.
6 Reaction Pressure: In general, the range of pressuxe
7 will be from about 0.10 to about 150 atmospheres, more
8 preferably from about 0.15 -to about 100 atmospheres, and
9 most preferably from about 0.2 to about 10 atmospheres.
Reaction Time: The reaction time is not narrowly
11 critical and will be determined by standard techniques. In
12 general, times will preferably be from 0.001 to 3600, more
13 preferably 0.01 to 360, and most preferably 0.02 to 60 seconds.
14 Batch or Continuous Basis: The present invention will
preferably be practiced on a continuous basis but can be done
16 batchwise.
17 Reaction Apparatus: The reaction apparatus to be used
18 with the present invention is not narrowly critical and a
19 wide variety of reactors may be employed including all of
those which are conventionally utilized for the sulfonation of
21 hydrocarbons. For example, falling film, scraped surface,
22 stirred tank, tank with sparger for introduction of SO3 and the
23 like. In those reactions according to the present invention
24 which employs a solvent or diluent, the preferred apparatus
is a tubular reactor having an inlet for admitting a stream
26 containing the crude oil plus any additive plus some recycle
27 reaction products, and an inlet for a stream containing the
28 SO3 plus the reaction solvent or diluent. Both streams
29 should be in turbulent flow.
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1 The reactor is preferably made of stainless steel but
2 any metal or non-metal having proper mechanical and corrosio~-
3 resistant properties may be utilized.
4 Neutralization: The sulfonic acid in the reaction pro-
ducts are neutralized with a monovalent basic compound such
6 as sodium hydroxide, ammonia, ammonium hydroxide, etc.
7 Extraction: While not absolutely necessary to the practice
8 of the present invention, it will generally be preferable to
9 extract the products from the reaction in order to remove
excess unreacted hydrocarbons from the micellar dispersions.
11 Extraction can precede or follow neutralization. Preferably,
12 any reaction solvent will first be stripped from the micellar
13 dispersion, the resulting unextracted micellar dispersion is
14 contacted with aqueous alcohol or water to permit extraction
of the micellar dispersion. Examples of useful alcohols
16 include those containing from 1 to about 5 carbon atoms,
17 also semi-polar organic compounds such as benzene are useful.
18 The unreacted hydrocarbon and salt contents of the final
19 micellar dispersion are controlled by both the solvent to
unextracted micellar dispersion ratio and solvent composition.
21 That is, from about 0.5 to about 5.0 lbs., preferably 1.0 to
22 about 3.0 lbs. and more preferably 1.5 to about 2.0 lbs. of
23 aqueous alcohol solution or (preferably) water is mixed with
24 each lb. of the unextracted micellar dispersion. The aqueous
alcohol is preferably isopropyl alcohol/water solution.
26 The mixture resulting after addition of the extraction
27 solvent will separate into either two or three phases; a
28 raffinate phase which consists primarily of unreacted hydro-
29 carbons, an extract phase which contains most of the micellar
50~3
1 dispersion product, and possibly (depending on the particular
2 extraction solvent used) a brine phase which contains salts
3 and water.
4 The raffinate phase is processed, e.g., by stripping
to recover the alcohol (if any) and water from the unreacted
6 hydrocarbon. The extract phase is fed to a stripper to remove
7 excess water and any alcohol from the micellar dispersion.
8 The brine phase, if any, can be disposed of or can be further
9 processed to recover salts, e.g., ammonium sulfate which can
be utilized as fertilizer.
11 Product Specification: The desired petroleum sulfonate
12 in the micellar dispersion has an average equivalent weight
13 within the range of about 350 to about 525, more preferably
14 about 375 to about 475 and most preferably about 390 to
about 445. This average equivalent weight range of the petro-
16 leum sulfonate is a major quality control parameter. The
17 equivalent weight of the petroleum sulfonate is defined as
18 the sulfonate molecular weight divided by the average number
19 of sulfonate groups per molecule. It indicates the relative
amount of monosulfonation and polysulfonation~ i.e., the
21 equivalent weight becomes lower as the polysulfonation increases.
22 Micellar Dispersions: The micellar dispersion contains
23 unsulfonated hydrocarbon, aqueous medium, and petroleum sul-
24 fonate. Optionally, cosurfactant and/or electrolyte can be
incorporated. Examples of volume amounts include about 0.2%
26 to about 90% hydrocarbon, about 5~ to about 95~ aqueous medium,
27 at least about 4~ of petroleum sulfonate, about 0.01 to about 20%
28 cosurfactant, and about 0.001 to about 5~ (weight ~ based on
29 aqueous medium) of electrolyte. The micellar dispersions can
be oil-external or water-external, or intermediate between
31 these.
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1 The hydrocarbon of the micellar dispersion is unsul-
2 fonated crude oil, or topped crude oil. The aqueous medium
3 can be soft water, water containing minor amounts of salts, or
4 brackish water. The cosurfactant can be an amine, aldehyde,
ketone, hydroxy-containing compound (including conventional
6 alcohols), ester, ether, etc., containing 1 to about 20 or
7 more carbon atoms. Numerous electrolytes are useful, preferably
8 they are inorganic acids, inorganic bases, and inorganic salts.
EXAMPLE
11 The example which follows is intended to more fully
12 illustrate the invention and is not to be considered as limit-
13 ing the invention in any way. Referring to Fig. 1, crude oil
14 ~as specified under the example) is pumped from a well 10,
can undergo an optional topping process 11 and either the crude
16 oil 12 or the heavy ends 13 flow into a sulfonation reactor 14
17 after mixing with optional sulfonation additives 15 and/or
18 optionally recycled reactor products 16. SO3 vapor 17 also enters
19 the sulfonation reactor 14 with or without an optional SO3
diluent 18 (as specified in the respective example). Sulfona-
21 tion products exiting from reactor 14 flow through cooler 19
22 into neutralization reactor 20 after optional SO2 and H2SO4 removal
23 21 and after optional mixing with recycled neutralized products
24 22. In the neutralization reactor 20 the sulfonated products
are neutralized by contact with water 23 and neutralization
26 agent 24 (e.g. ammonium hydroxide). The neutralized products
27 flow through cooler 25 and exit as the micellar dispersion 26.
28 Alternatively, the micellar dispersion 26 may be extracted
29 by mixing with extraction solvent 27 (as described in the
reSpective example) and conducted into phase separator 28 for
31 separation into two or three phases.
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1 The plant shown in the drawing is located near the
2 Bridgeport, Illinois (USA) field and is fed feedstock consisting
3 of Bridgeport crude oil (36.5 API Gravity) and 10 pounds of
4 vapor sulfur trioxide per 100 pounds of crude oil. Each mole
of sulfur trioxide is diluted with 6 moles of crude oil light
6 ends (those boiling below 150F.) and 5 parts by weight of
7 reaction products are recycled to mix with each weight of
8 fresh crude oil feed. The reaction is carried out at about 150F.
g and one atmosphere pressure for a reaction time of about 15
minutes.
11 Each 110 pounds of reaction products are neutralized
12 with 3.1 pounds of ammonia mixed with 237 pounds of water. A
13 substantial portion of the unreacted hydrocarbon is removed by
14 extracting with water and removing the resulting oil-rich
phase. About one volume of n-amyl alcohol is added per 100
16 volumes of the final micellar dispersion.
17 The micellar dispersion (about 0.07 pore volumes) is
18 then injected into the previously water flooded Bridgeport Field.
19 Injection of the micellar dispersion is followed by injection
of approximately one pore volume of a drive fluid consisting of
21 500 parts per million (average) of Dow 700 Polymer, a partially
22 hydrolyzed polyacrylamide manufactured by Dow Chemical Company
23 of Midland, Michigan in connate water. Residual oil is dis-
24 placed and produced. A portion of the Bridgeport crude oil
thus produced is used as feed for production of additional
26 micellar dispersion as described above.
27 MODIFICATIONS OF THE INVENTION
28 It should be understood that the invention is capable of
29 a variety of modifications and variations which will be made
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1 apparent to those skilled in the art by a reading of the speci-
2 fication and which are to be included within the spirit of the
3 claims appended hereto.
