METHOD OF TRANSPORTING VISCOUS HYDROCARBONS

METHODE D'ACHEMINEMENT D'HYDROCARBURES VISQUEUX

English Abstract

METHOD OF TRANSPORTING VISCOUS HYDROCARBONS
Abstract of Disclosure
An improvement in the method of transporting
viscous hydrocarbons through pipes is disclosed. Briefly,
the improvement comprises adding water containing an ef-
fective amount of a low molecular weight alkaryl sulfonate.

Claims

-6-
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In the method of pumping a viscous hydrocar-
bon through a pipe the improvement which comprises forming
an oil-in-water emulsion by adding to said hydrocarbon from
about 20 to about 80 volume percent of an aqueous solution
containing an effective amount, in the range of about 100 to
about 2,000 parts per million, based on said hydrocarbon, of
a water-soluble alkaryl sulfonate having a molecular weight
below about 410, said alkaryl sulfonate being represented
by the formula
R(n)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 4 to 16 carbon atoms, n is an integer of
1 or 2, M is sodium, potassium, or ammonium, and the total
number of carbon atoms in the alkyl groups is in the range
of 8 to 16.
2. The method of claim 1 wherein the alkaryl
sulfonate has a molecular weight below about 375 and is
represented by the formula
<IMG>
wherein R is an alkyl group containing from about 9 to
about 14 carbon atoms.
3. The method of claim 2 wherein the hydrocar-
bon is a crude oil.
4. The method of claim 1 wherein the amount of
aqueous solution added to said hydrocarbon is in the range
of about 30 to about 60 volume percent, based on said hydro-
carbon.

-7-
5. The method of claim 4 wherein the amount of
alkaryl sulfonate is in the range of about 200 to about
1,000 parts per million, based on said hydrocarbon.
6. The method of claim 5 wherein the alkaryl
sulfonate has a molecular weight below about 375 and is
represented by the formula
<IMG>
wherein R is an alkyl group containing from about 9 to
about 14 carbon atoms.
7. The method of claim 6 wherein the hydrocar-
bon is a crude oil.
8. The method of claim 7 wherein the alkyl group
contains about 10 to about 13 carbon atoms.
9. The method of claim 8 wherein the alkaryl
sulfonate has a molecular weight of about 334.

Description

,
METHOD Ol~ TRANSPORTING VISCOU~ l-IYDROCARBONS
Background of the Invention
Field of the Invention
.. _ . .... . .
The invention is in the cJelleral field oE improved
methods of pumping viscous hydroc~rbons through a pipe, such
as a well-bore or a pipeline.
General Background
....
The movement of heavy crlldes through pipes is
difficult because of their high viscosity and resulting
low mobility. One method of improviny the movemerlt of
10- these heavy crudes has included adding to the crude ]ight-
er hydrocarbons (e.g. kerosine distillate). This reduces
the viscosity and thereby improves the mobility. This
method has the disadvantage that it is expenslve and -the
kerosine distillate is becoming difficult -to obtain.
15Another method of improving the movement of these
' heavy crudes is by heating them. This requires the instal-
lation of expensive heating equipment and thus is an expen-
sive process.
Still another method of moving heavy crudes
through pipes uses oil-in-water emulsions which use sur-
factants to form the emulsions.
We have found that when an alkaryl sulfonate is
used as the surfactant the molecular weight of the sulfo-
nate is important. As an illustrative example a sulfonate
having a molecular weight of about 334 provides much better
results than a sulfonate having a molecular weight of 427.
Brief SumTnary of the Invention
Briefly stated, the present invention is direc-
ted to an improvement in the method of pumping a viscous
hydrocarbon through a pipe wh~rein the improvement comprises
forming an oil-in-water emulsion by adding to said hydrocar-
bon from about 20 to about 80 volume percent water contain-
ing an effective amount of a water-soluble alkaryl sulfonate
having a molecular weight below about 410 and preferably
below about 350.
- . . . . :
. - ,: : .
' ' .:' : ., :.:'',. ,. ;' ' - : . :. . ' , : , ~ '
. . - . . - -
:: : : - - : : -
- . . . ..
: : , . . ::
.
.

~o~
;~-
The speci~ic nature of ~he water-soluble alkaryl
sulfonate is provided in the det:ailed description.
De-talled D~scrlption
Insofar as is known our method is suitable for
use with any viscous crude oil~ It is well known that
crude oils often 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 a-
mount of water is in the range of about 30 to 60 volume
percent. The water can be pure or can have a ~elatively
high amount of dissolved solids. Any water normally found
in the proximity of a produclng oil-well is suitable.
Suitable water-soluble alkaryl sulfonates have a
molecular weight below about 410 and are represented by
the formula
~( )Ar-SO M
wherein Ar is an aromatic moiety which is phenyl, tolyl,
xylyl or ethylphenyl, R is a linear or branched-chain alkyl
group containing 4 to 16 car~on atoms, n is l or 2, but
preferably is 1, the total number of carbon atoms in alkyl
groups is in the range of 8 to 16, and M is sodium, po-
tassium or ammonium.
More suitably, the water-soluhle alkaryl sulfo-
nates have a molecular weight below about 375, preferably
below about 350.
The more suitable and preferred alkaryl sulfonates
are represented by the formula
R ~ SO3Na
wherein ~ is an alkyl group containing 8 to ]6, more suit-
ably 9 to 14, and preferably lO to 13, carbon atoms. The
alkylbenzene sulfonates usually are mixtures containing alkyl
groups in the carbon range specified.
Suitable and preferred amounts of the alkaryl sul-
fonates, based on the hydrocarbon, are shown below.
: . ~ - - - - ~ . .: . -
, . , - , , ' ' ~ :
. .: . :

5~.~
--3--
~uit~ble Preferred
_ (parts per million)__
Alkaryl sulfonate l0n - ~,000 200 - 1,000
In order to lllustrate the ~ature or the presen~
invention still more clearly the follo~ing exa~ples will be
~iven. It is to be understood, however 7 that the invention
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 lab-
oratory to simulate watex produced at the well. It con-
tained 4720 ppm total solids.)
The specific nature of the su]fonates tested
will be given in the examples.
Viscosities were determined using a Brookfield
viscometer, Model LVT with No. 3 spindle. The procedure
is described below.
Test Procedure
Three hundred ml of crude oil, preheated in a
large container to about 93C. in a laboratory oven, was
transferred to a Waring blender and stirred at medium speed
until homogeneous. Stirring was stopped, temperature re-
corded, and the viscosity measured using the Brookfield
viscometer at RPM's (revolutions per minute) of 6, 12, 30
and 60. 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 difference in viscosity values on the crude
alone 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.
.
,.
- . . -
. . : ' -: .

2.~Y
The crude corresponded to that used in combination with -the
aqueous surfactant.
EXAMPLE 1
This example is illustrative and shows the vis-
cosity values obtained on the crude alone and a combinationof 50 volume percent crude oil and 50 volume percent water
which contained 625 ppm of an alkylbenzene sodium sulfonate,
wherein the alkyl groups were linear, and having a molecular
weight of about 334 (containing an average of about 11 car-
bon atoms in the alkyl groups).
The results are shown in Table I.
TABLE I
CRUDE OIL PLUS 300 ML WATER
CRUDE OIL ALONE CONTAINING 625 PPM OF
~300 ML)DESCRIBED SULFONATE
Dial Viscosity Dial Viscosity
R Reading cp Readiny cp
6 28.5 5,700 2 400
1251.5 5,150 3.5 350
30Offscale - 6 240
60Offscale - 12.8 256
30 Offscale - 6 240
12 51 5,100 5 500
6 24.7 4,940 4.5 900
25 Test TemEerature 82C Test Tempera-ture 66C
'
EXAMPLE 2
This example is comparative and shows the viscos-
ity values obtained using a sodium alkylbenzene sulfonate
having a molecular weight of 427. This material was ob-
tained by making a blend of a 375 molecular weight sodium
alkylbenzene sulfonate and a 510 molecular weight sodium
alkylbenzene sulfonate.
Viscosity values were obtained on the following:
(a) crude oil alone,
(b) crude oil plus 50 volume percent water containing
2500 ppm of the described sulfonate, and
(c) crude oil plus 50 volume pexcent water containing
5000 ppm of the desired sulfonate.
The results are shown in Table II. ~-

_
T~BL~
CRUDE OIL. PLUS CRUD~ OIL PLUS
300 ML WATER CON- 300 ML WATER CON-
CRUD~ OIL ALONE TAINING 2500 PPM TAINING 5000 PPM
(300 ML) SULE`ONATE __ SULFONATE
Dial Viscoslty Dial Viscosity Dial Viscosity
RPM Readiny cp Reading _ cp Reading _ cp
6 6.7 1,340 91.2 18,2401.7 340
12 11.3 1,130 Offscale - 4 400
10 30 26.3 1,052 Offscale - 7 280
52 1,040 Offscale - 10.3 206
26 1,052 Offscale - 7.5 300
12 10.3 1,030 Offscale - 7.5 750
6 2.6 1,060 82.5 16,5009.3 1,860
15 Test Temp 82C Test Temp 72C Test Tem~ C
The data in Table II shows that this sulfonate i5
effective at 5000 ppm but is not effective at 2500 ppm.
Thus, having described the invention ln detail,
it will be understood by those skilled in the art that
certain variations and modifications may be made without
departing from the spirit and scope of the invention as
defined herein and in the appended claims.
: - . . .
' ' : : .
: ,: - - : : . :