Note: Descriptions are shown in the official language in which they were submitted.
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-1~ Case 6393
METEIOD OF TRANSPORTING VISCOUS HYDROCARBONS
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Background oE the Inven-tion
Field of the Invention
The invention is in the general Eield of improved
methods oE pumping viscous hydrocarbons through a pipe, such
as a well-bore or a pipeline~
General Background
The mo~ement oE heavy crudes through pipes is dif-
~icult because of their high viscosity and resulting low
mobility. One method of improving the movement of t.hese
heavy crudes has included adding to the crude li~hter hy-
drocarbons (e.g. kerosine distillate~. This reduces the
viscosity and thereby improves the mobility. This metho~
has the disadvantage that it is expensive and the kerosine
distillate is becoming difficult to obtain.
Another method of improving the movement of these
heavy crudes is by heating them. Thi.s requires the instal-
lation of expensive heating equipment and thus is an expen-
sive process.
The use of oil-in-water emulsions, which use sur-
factants to form the emulsion, is known in the art.
U. S. Patent No. 3,943,954 teaches lowering theviscosity of viscous hydrocarbons by adding an aqueous solu-
tion containing an anionic surfactant together with a guani
dine salt and optionally with an alkalinity agent and/or a
nonionic surfactant. The patent teaches that the guanidine
salt is required.
Commonly asigned U.S. Patent No. ~,2399052 discloses
a method of transpor-ting a viscous hydrocarbon through pipes
wherein the method uses water containing an effective amount
o an alkaryl sulfonate having a molecular weight below about
410. The application contains data which shows that high
molecular weight sulfonates are not effec-tive in the me-thod.
We have found that using a Cl-C4 alcohol with an
alkar~l sulfona-te having a molecular weight of about 415 to
about 470 provides a composition, which when used in water
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and added to a viscous hydrocarbon, provides a reduction in
viscosity.
Brief Summary of the I _ention
Briefly stated, the present inven-tion is directed
to an improvement in the method of pumpiny a viscous hydro~
carbon through a pipe wherein the improvement comprises add-
ing from about 20 to about 80 volume percent water containing
an effective amount of a combination of an alkaryl sulfonate
having a molecular weight of about ~15 to about 470 and a
Cl-C4 alcohol~
Detailed Description
Insofar as is known our method is suitable for use
with any viscous crude oil. ~t is well known that crude oils
o~ten contain a minor amount of water.
The amount of water which is added to the hydro-
carbon is suitably in the range of about 20 to about 80
volume percent based on the hydrocarbon. A preferred amount
of water is in -the range o-f about 30 to 60 volume percent.
The water can be pure or can have a relatively high amount
of dissolved solids. Any water normally found in the prox-
imity of a producing oil-well is suitable.
Suitable alkaryl sulfonates for use in my invention
have a molecular weight of about ~15 to about 480 and are
represented by the formula
R - Ar - SO3M
wherein Ar is an aromatic moiety which is phenyl, tolyl, xylyl
or ethylphenyl, R is a linear or branched-chain alkyl group
containing 17 to 22 carbon atoms, with the -total number of
carbon atoms in the combined RAr moiety being in the range
of 17 to 22, and M is sodi~, potassium or ammonium, but
preferably is sodium.
The preferred alkaryl sulfonates are sodium alkyl-
benzene sulfonates, wherein the alkyl grollp contains 17 to
22, more suitably 17 to 21, and preferably 18 to 20, carbon
a-toms.
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The alkaryl sulfonates can be natural or synthetic.
Usually, they are mixtures containing alkyl groups in the
carbon range specified.
Suitable alcohols are those having at least some
solubili~y in water. From a practical viewpoint the C4
isomers are the highest carbon number suitable. Accordingly,
suitable alcohols are Gl-C4 aliphatic alcohols. The preferred
alcohols are methanol, ethanol and isopropanol.
A suitable amount oE alkaryl sulfonate is in the
range of about 500 to about 10,000 parts per million based
on the hydrocarbon. On the same basis the preferred amount
of alkaryl sulfonate is in the range of about 1,000 to about
5,000 parts per million.
A suitable amount of alcohol is in the range of
0.1:1 to 10:1, expressed as parts by weigh-t basea on the
alkaryl sulfonate. On the same basis the preferred amount
of alcohol is in the range of 0.5:1 to 5:1.
In order to illustrate the nature of the present
invention still more clearly the following examples will be
given. It is to be unders~ood, however, that the in~ention
is not to be limited to the specific conditions or details
set forth in -these examples except insofar as such limita-
tions are specified in the appended claims.
The following materials were used in the tests
described herein:
Crude Oil - Goodwin lease crude from Cat Canyon
oil field, Santa Maria, California
Water - Goodwin synthetic (Water prepared in la~-
oratory to simulate water produced at the well. It con-
tained 5000 ppm total solids.)
Viscosities were determined using a Brook~ield
viscometer, Model L~T with No. 3 spindle. The procedure
is described below.
The ~ollowing materials were used in the tests:
Methyl alcohol - reagent grade
Surfactant "A" - an alkylbenzene sulfonate having
a molecular weight in the range o~ 415-430
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Surfactant "s" - an alkylbenzene sulfonate having
a molec~llar weight in the range of 440-470
SurEactant "C" - an alkylbenzene sulfonate having
a molecular weight in the range of 490-510
Test Procedure
Three hundred ml of crude oil, preheated in a
large container to about 93C. in a laboratory oven, was
transferred to a T~aring blender and stirred at medium speed
until homogeneous. Stirring was stopped, temperature re-
corded, and the viscosity measured using the Brookfieldviscometer at RPM's (revolutions per minute) of 6, :L2, 30
and 60 and then back down 30, 12, and 6 RPM. Viscosity was
calculated by using a multiplication factor of 200, 100, 40
and 20 for the respective speeds times the dial reading on
the viscometer.
It may be well to mention that the final result
at 6 RPM is an indication of the stability of the solution
being tested.
The test was repea-ted using 300 ml crude oil plus
300 ml of the Goodwin synthetic water containing varying
amounts of the described surfactants and combinations of the
described surfactants with methyl alcohol.
An additional procedure was used on the crude oil-
water-surfactant composition and the crude oil-wate r- surfac-
tant-alcohol composition. This procedure consisted of
stirring the emulsions a second time, allowing them to set
for two minutes upon completion of stirring, then making the
viscosity determination as previously. This procedure is a
more severe test of long term stability ~or emulsions.
The difference in viscosity values on the crude
a]one in the examples is due to the varying amount of water
naturally present in the crude. For this reason the viscos
ity value of the crude alone was obtained in each example.
The crude corresponded to that used in combination with the
aqueous surfactant.
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EXA~PLE 1
This example is both comparative and illustrati~e.
It shows the beneficial effect of adding methyl alcohol to
Surfactant "A". Viscosity values were obtained on the fol-
lowing:
(a) 300 ml crude oil alone,
(b) 300 ml crude oil plus 300 ml water containing 1.21 g
(62 percent active) Surfactant "A" (2500 ppm), and
(c) 300 ml crude oil plus 300 ml water containing 1.21 g
(62 percent active) Surfactant "A" (2500 ppm) and 2.0 ml
methyl alcohol (~5300 ppm~
The results for runs (a~ and (b) are shown in
Table I while the results for run (c) are shown in Table II.
TABLE I
Crude Oil Plus 300 ml
Water Containing 1.21 g
Crude Oil Alone (62% Active) Surfactant "A"
(300 ml) (2500 ppm~
Viscosity, cp ~iscosity, cp
20RPM No. 1 No. 1 No. 2
6 11,200 ~00 12,~00
12 9,950 650 o.S.
O.S. 320 O.~.
O.S. 204 O.S.
2530 O.S. 300 O.S.
12 9,500 580 4, lao
6 9,500 1,600 5,200
O.S. = Offscale O.S. = Offscale
Test Temperature 87C Test Temperat-ure 7~C, 66C
Composition foamed badly
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TABLE II
C~ude Oil Rlus 300 ml Water Containing
1~21 g (62% Active) Surfactant 'IA" (2500 ppm)
_ And 2_0 ml Me_ yl Alcohol
Viscosity, cp
RPM No. 1 No. 2
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6 140 200
12 180 100
28 56
10 60 36 52
28 32
12 70 80
6 80 1~0
Test Temperature 78C, 74C
Composition had very little foam
EXAMæLE 2
This example is both comparative and illustrative.
It shows the beneficial effect of adding methyl alcohol to
Surfactan-t IIB'I. Viscosity values were obtained on the ol-
lowing:
(a) 300 ml crude oil alone,
(b) 300 ml crude oil plus 300 ml water containing 1.21 g
(62 percent active) Surfactant 'IBlt (2500 ppm), and
(c) 300 ml crude oil plus 300 ml water containing 1.21 g
(62 percent acti~e~ Surfactant "s" (2500 ppm) and 2.0 ml
methyl alcohol (~ 5300 ppm).
The results for runs (a) and (b) are shown in
Table III while the results for run (c) are shown in Table I~.
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TABLE_ I I I
Crude Oil Pl7ls 300 ml
Water Containing 1.21 g
(62% Active) Surfactant "B"
Crude Oil Alone (2500 ppm)
(300 ml) Viscosi~.y, cp
RP~lVisc _ity, cp No. 1 No. 2
6 11,880 960 2,100
12 O.S. 1,200 1,650
10 30 O.S. 800 1,320
~0 o.S. 100 130
o.S. 112 172
12 O.S. 160 260
6 10,400 340 360
15O.S. = Offscale Test Temperature 78C, 70C
Test Temperature 91C Composition had moderate foa~
TABLE IV
Crude Oil Plus 300 m]. Water Containing
1.21 g (62% Active) Surfactant "B" (2500 ppm)
20And 2.0 ml Methyl Alcohol
Viscosi~y, cp
RPM No. 1 No. 2
6 ~0 160
12 50 80
25 30 60 52
52 36
56 60
12 180 70
6 360 340
Test Temperature 77C, 73C
Composition had very little foam
EXA~5P LE 3
This example is comparative in that it shows that
addition of methyl alcohol has no beneficial effect on an
alkylbenzene sulEonate having a molecular weight of 490-510
(SurEactant "C"). Viscosity values were obtained on the fol-
lowing:
(a) 300 ml crude oil alone,
(b) 300 ml crude oil plus 300 ml water containing 1.21 g
(62 percent active) Surfactant "C" (2500 ppm), and
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(c) 300 ml crude oil plus 300 ml water containing 1.21 g
(62 percent active) Sur~actant "C" ~2500 ppm) plus 2.0 ml
methyl alcohol (,~5300 ppm~.
The results for runs (a~ and (b) are shown in
5 Table V while the results for ,run (c) are shown in Table YI.
TABLE V
CrudP Oil P].us 300 ml
~ater Containing 1.21 g
(62g~ Act;ve) Surfactant "C"
Crude Oil Alone(2500 ppm~
_ (300 ml~ _~iscos_ty, cp
RPM~iscosity, cpNo~ l No. 2
6 12,260 0.5. O.S.
12 O.S. O.S~ O.S
O.S. O.S. O.S.
O.S~ O~S. O.S.
O.S~ O.S~ O.S.
12 O.S. O.S. O.S.
6 lll600 O.S. O.S.
20O.S. = Offscale O.S. - Offscale
Test Temperature 90C Test Temperature 79C, -
Composition ~ailed
TABLE YI
_,
Crude Oil Plus 300 ml ~ater Containing
251.21 g (62~ Active) Sur~actant "C" (2500 ppm)
And 2~0 ml Methyl Alcohol
~llSCOSi
RPM No. 1 No. 2
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6 o.S. O.S.
12 O.S. O.S.
O.S. O.S.
O.S. O.S.
30. O.$. O.S.
12 O.S. O.S.
: 35 6 O.S. O.S.
O.S. - Offscale
Test Temperature 7~C, -
Composition failed
The tes.t results Ero~ the examples show cle~rly
that addi.tion of a small amolmt of ,methyl alcohol to Sur-
,~actants "A" and "B'l provided a significant :reduction in
vîscosity. The test results show that addition o~ methyl
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alcohol to Surfactant "C" (molecular weigh-t 490-510) did not
provide any improvement.
Examples 1-3 are repeated substituting ethyl alco-
hol and isopropyl alcohol ~or methyl alcohol. Similar results
are obtained.
Thus, having described the invention in detail, it
will be understood by those skilled in the art that certain
variations and modifications may be made without departing
from t.he spirit and scope of the in~ention as defined herein
and in the appended claims.
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