CA1117568A - Method of transporting viscous hydrocarbons - Google Patents

Abstract

Case 6325 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 specific ethoxylated alcohols.

Description

METIIOD OF T~NSPOR'l'LNG _ S OUS ~lYDROCAP.BONS
B~ nd of the Inverltion Field of the Inverltion ___~_ _ The invent:ion is in the general field of irnproved methods of pump;ng viscous hydroc~rbons through a pipe, such as a well-bore or a pipeline.
eneral Backgroun_ The movement of heavy crudes through pipes is difficult because of their high viscosity and resulting low mobility. One method of improving -the movement of 1~ these heavy crudes has included adding to the crude light-er hydrocarbons (e.gO kerosine distillate). 'rhis reduces the viscosity and thereby improves the mobility. This method 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. This requires the instal-lation of expensive heating equipment and thus is an expen-slve process.
Still another method of moving heavy crudes through pipes uses oil-in-water emulsions which use sur-fac~tants to form the emulsions.
U. S. Patent No. 3,943,954 teaches a method of moving viscous hydrocarbons through a pipe wherein the method uses a solution containing an anionic surfactant or soap such as sodium tridecyl sulfate or sodium oleate together with a guanidine salt and optionally with an alkalinity agent and/or a nonionic surfac-tant such as polyethoxylated alcohols.
To our knowledge there is no -teachiny of viscos-ity reduction of viscous hydrocarbons using an ethoxylatedalcohol per se as the surfactant. Surprisinyly, we have found that certain ethoxylated alcohols are useful to re-duce the viscosity of viscous hydrocarbons~
Brief Summary of the Invention Briefly stated, the present invention is directed to an improvement in the method of pumping a viscous ~k ~,' , ', . ' '~ .
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. 3 hydrocarbon through a pipe wherein the improvement comprises forming an oil-in-water em~llsion 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 50 to about 20,000 parts of an ethoxylated alcohol~
Ethoxylated alcohols which are used in our invention are represented by the formula RO(CH2CH2O)nH
wherein R is an alkyl group containing from 10 to 20 carbon atoms and n is a number in the range of about 5 to about 40.
The ethoxylated alcohol is the only essential surfac-tant used in our invention.
Detailed Description Insofar as is known our method is suitable for use lS 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 hydrocarbon 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 of 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 proximity of a producing oil-well is suitable.
The ethoxylated alcohols which are used in our invention are represented by the formula R(CH2CH2~nH
wherein R is an alkyl group containing from 10 to 20, preferably 12 to 18, carbon atoms and n is a number in the range o~ about 5 ~o~about 40, preferably about 10 to about 25. Linear alkyl groups are particularly suitable. While more than 40 moles - of ethylene oxide may possibly be used, materials containing this amount are not particularly better and are not readily available.
We have found that ethoxylated alcohols outside of the described range, particularly lower than the described ' :

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range, either are not s~itah1e or give such poc,r results that they are not col~nercial:L~ ~easi~1e.
Suitable and pree~rred arnounts of the ethoxylated alcohols, based on the hydrocarbon~ are shown ~e]ow.

5Sui-table Preferred ~ ts per million) Ethoxylated alcohol 50 20,000 200 - 5,000 In order to illustra~e the nature of the present invention still more clearly the following examples will be given. It is to be understood, however, that the invention is not to be limited to -the speciflc conditions or details set forth in these examples except insofar as such limita-tions are specified in the appended claims.
The following mater:ials were used in the tests lS described herein:
Crude Oil - Goodwin lease crude from Cat Canyon oil field, Santa Maria, California (Examples l-9) Water -- Goodwin syn-thetic (Water prepared in lab-oratory to simulate water produced at the well. It con-tained 4720 ppm total solids.) The specific nature of the alcohol ethoxylates 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 stirrecl at medium speed until homogeneous~ Stirring was stop~ped, temperature re-corded, and the viscosity measured using the Brookfield viscome-ter at RPM's ~revolutions per minute) of 6, 12, 30 and 60. Viscoslty was calculated by using a multiplicat.ion factor of 200, l00, 40 and 20 for the respectiye speeds times the dial reading on the viscometer.

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,~, It m~y be well to m~n~i.on ~hat the ~inal re~sult at 6 RP~I is ~n i.ndica~.ion of- th~ st~bilit~ of the solution bein~ tested.
The cliffc?rerl(e i.n v.iscosity valu.e.s on the crude alon~ in the e~xamples i.s due to Ihe varying anlount of water naturally pr~s~nt in the crude. L~lor th.is reason the viscos-ity value of the crude alone was obtained .in each example.
The crude co.rresponded to that used in comblnation with the aqueous su.rfactant.

E'XAMPLE 1 This example is illus-trative and shows the vis-cosity values obtainecl on the crude alone and a combination of 50 volume percent crude oil and 50 volume percent water which contained 2,000 ppm of an ethoY.ylated alcohol repre-sented by the formula RO(cH2cH2O)lo.6 wherein R is a linear alkyl group containing 16 to 18 car-bon atoms. The 10.6 moles of ethylene oxide corresponds to about 65 weight percent.
The results are shown in Table I.

TABLE I

CR~DE OIL ALONE CONTAINING 2,000 PPM OF
( 300 ML)DESCRIBED AI,COHOL ETHOXYLATE
DialViscosity ~Dlal Viscosi ty RPM ~ p _ Reading _ cp 6 11 2,200 0.5 100 12 20.5 2~050 1.5 150 51 2,:040 2 80 30 60 99 1, 980 3 60 4~ 1,920 2 80 12 191 j 900 ~.. 5 ~.50 6 10 2,000 1 200 7~ 3 E 'lPLf;,S 2 5 These examples are ill.ustrat.ive and show the viscosity v~lues obtained on t~le crucle al,one and a combi-nation of 50 volume percent crude oil and 50 volume percent w~ter which contained 2,000 ppm of various ethox~lated al-cohols. The ethoxyla-ted alcohols had the following composi-tions.

Example Moles of Weight Percent No. A ~ C No. Ethvlene Oxide Ethylene Oxide . .
10~ 2 12 - 18 11 90 4 10 - 12 5.7 60 12 - 14 ~ 7 60 Only the Initi.al and Final 6 RPM viscosity values are shown. The results are shown in Table II.

TABLE II
''~~'^~~ Crude Oil Plus Example Crude Oil Alone Ethox~ ted Alcohol _ No. Initial, cp Final, cp I_ tlal,_~ Flnal, cp

2 ~400 3600 80 180

3 3600 3000 100 200

4 3800 3600 300 1400 EXAMPLES 6~9 .
These examples are comparative and show the re-sults obtained on ethoxylated alcohols outside the range of our invention. The procedure and amounts were the same as in previous examples. The ethoxylated alcohols had the following composit.ion.

Example Moles o~ Wei..~ht Percent No.: Alkyl Group-C No. Ethylene Oxide E~hylene Oxide 6 12 - 16 l..2 22 7 10 ~ 12 2.5 ~0 8~ 12 - 1~ 3 40

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Orll~ Lhe In:itiaL and ~'incl] 6 ~PM ~/iscosity values are shown. The resul~s are shown in rrable lrI~

TABLE tI_ Crude Oil Plus Example _ Crude Oi:L Alone _ _ Ethoxylated Alcohol No. lnitial, cp Final, c~ Inltial, cp Final, cp

6 2900 23001~,000 15,000

7 3400 3000l9,000 Offscale

8 -- --Offscale* Offscale*

9 3600 3000Offscale* Offscale*
* Would no-t blend XAMPLE ~0 This example shows that the ethoxylated alcohols of our invention work in a different crude from that used in the other examples.
The crude oil used in this example came from the Loco Field, Stephens County, Oklahoma.
The ethoxylated alcohols had the follo~ing com-position: linear C12-C14 alkyl groups; 60 weight percent, 7 moles, ethylene oxide. 500 parts per million of ethoxy~
lated alcohol were used.
The procedure used was the same as in previous examples.
Only the Inltial and Final 6 RPM viscosity values are shown. The resul-ts are shown in Table IV.

TABLE IV
Crude Oil Plus Crude Oil Alone Ethoxylated Alcohol Initlal, cy _inal, cp Initial,~cp Final! cp ~50 440 20 138 Thus; having described the invention in detail, it will be understood hy those skilled in the art that certain variations and modifications may be made without .

-departing from the spirit and ~cop~ o the invention a.s defined herein and in the app~nded claim3.
We claim:

Claims (8)

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 50 to about 20,000 parts of an ethoxylated alcohol, which is represented by the formula RO(CH2CH2O)nH

wherein R is an alkyl group containing from 10 to 20 carbon atoms and n is a number in the range of about 5 to about 40.

2. The method of claim 1 wherein n is a number in the range of about 10 to about 25.

3. The method of claim 2 wherein R is an alkyl group containing 12 to 18 carbon atoms.

4. The method of claim 3 wherein R is a linear alkyl group.

5. The method of claim 1 wherein:
(a) about 30 to about 60 volume percent of the aqueous solution is added to the hydrocarborn, and (b) n is a number in the range of about 10 to about 25.

6. The method of claim 5 wherein R is an alkyl.
group containing 12 to 18 carbon atoms.

7. The method of claim 6 wherein R is a linear alkyl group.

8. The method of claim; 5, 6, and 7 wherein the ethoxylated alcohol is the only essential surfactant in the aqueous solution.