CA1305011C - Crude oil emulsions containing a fluorochemical surfactant - Google Patents

Abstract

ABSTRACT
6-16476/=/CGC 1278 Crude oil emulsions containing a fluorochemical surfactant A transportable crude oil in water emulsion which is stable to both breakdown and phase inversion up to at least about 50°C, containing an effective, soluble emulsion stabilizing amount of an anionic, nonionic or amphoteric fluorochemical surfactant, and optionally a hydrocarbon surfactant, and a method of transporting a crude oil in the form of such emulsion.

Description

~3~5~11 6-16476/=/CGC 1278 Crude oil emulsions containing a fluorochemical surfactant The present invention relates to an improved method of pumping andJor transporting viscous crude oils. More particularly, the present invention relates to the introduction into crude oils in the presence of water, of an effective amount of a surfactant package that contains at least one fluorochemical surfactant to form low-viscosity crude-oil-in-water emulsions.

Viscosity frequently limits the rate crude oil can be produced from a well. For example, in wells that are pumped by a sucker rod string, viscous drag by the crude oil on the string slows its free fall by gravity on the downstroke. On the upstroke, this drag also slows the string, decreases oil flow through the production tubing, and increases the power required to raise oil and rod string. In some instances where the oil is highly viscous~ such as the Boscan field in Vene~uela, the strenght of the sucker rods limits the depth at which the pump can be operated. Alternatively, hydraulic pumps can be placed at the bottom of the well, but they must still overcome the high viscous drag that reqNires high power oil pressures and high pump horsepower.

~The downhole pump usually provides the pressure required to pump the produced oil from the wellhead to surface gathering tanks. Where viscosity is high, this may require the use of extra stren~th wellhead ~equipment (packings, gaskets7~heavy walled pipes and the like) to withstand the pressures required to move such viscous oil from wellhead to stDrage tank.
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It has been proposed heretofore to reduca the viscosity of heavy crude o1ls prior to pumping by introducing low viscosity crude oils, white oil, kerosene or the like into the well bore to dilute or thin the produced crude. In rod pumped wells, it is common to surround the sucker rod string with an extra tubing. Low viscosity oil is pumped down this tubing , ' ' : .
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so that the string is surrounded by lower viscosity oil. This added light oil then mixes with the viscous crude near the traveling valve of the pump to lighten and thin the column of crude oil being pumped from the well thTough the annulus fo}med by the inner and the production tubings of the well. Alternatively, low viscosity oil can be pumped down hollow sucker rods and the diluted crude oil producted through the annulus between the hollow rod string and the tubing.

The resulting produced crude has reduced viscosity and is more economically transported; However, these low viscosity diluents are expensive and not always available and have to be reclaimed from the diluted crude.

Another method for reducing the viscosity of heavv crudes is transporting them at elevated temperatu}es. This method however, is very expensive because the decrease in viscosity per degree temperature increase i5 very low. Also, the necessary heating e~uipment and power re~uirements are costly.

Other approaches that have been suggested to reduce viscosity of asphaltenic crude deposits include the use of a~ueous hydrocarbon surfactant solutions to form low viscosity oil-in-water emulsion as shown in U.S. Patents Nos. 3,943,954, 4,265,264, 4,429,554 and 4,239,052. Such emulsions generally contain a rather high percent of water, for example 10-40 % water, which must bs removed. Removal is not always easy and yields large volumes of water contaminated with oil. High treating temperatures are re~uired for separation of water and this results in additlonal expenditures. Such emulsions often become unstable at a critical flow rate and invert to high viscosity water-in-oil emulsions.
As a result~ pumping efficiency decreases.
:
It is thus an object of the present invention to obviate many of the drawbacks and deficiencies associated with the various prior art technique that are presently used in the attempt to diminish the problems associated with the production and transportation of crude oils. This object is achieved by employing a surfactant package containin~ at least ~ :

35~

one fluorochemical surfactant which, in the presence of water, will form an oil-in-water emulsion of the viscous crude, said emulsion having a lower viscosity than the unemulsified crude.

One embodiment of the present invention relates to a crude oil in water emulsion, which i9 stable to both breakdown and phase inversion up to at least about 50~C~ said emulsion containing an effectiva, soluble, emulsion stabilizing amount of a fluorochemical surfactant of the formula (~f~nAmQ (I) wherein Rf is an inert~ stable, oleophobic and hydrophobic fluoroaliphatic group having up to 20 carbon a-toms;
n is an integer from 1 to 3;
A is a direct bond or an organic linking group and is covalently bonded to both Rf and Q;
Q is an anionic, nonionic or amphoteric group; and m is an integer from 1 to 3;
wherein the amount by weight of said fluorochemical surfactant present in said emulsion being between 0.001 and 1 % by weight of said emulsion, in the presence or absence of up to 2 % by weight of a crude oil emulsion promoting hydrocarbon surfactant, with the proviso that at least 0.005 %
by weight total fluorochemical and hydrocarbon surfactant is present, and whereiD said emulsion contains 15 to 90 percent by weight water, based UpOD the weight of emulsion, such that the viscosity of the emulsion is less~than 50 % of the viscosity of said crude oil.
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Preferablv the amount of water present in the emulsion is between 20 to 70 % by weight, most preferably between 25 to 60 % by weight. The water ~employed may be for example potablel brackish water or brine. Crude oils themselves often contain considerable amounts of water. Generally, the ~source of water for use in the emulsion formation is not critical.

The nature of the Eluorochemical surfactant employed is generally not critlcal, but should be compatible with the crude oil emulsified. In particulart the fluorochemical surfactants of use are those which are ' :

. . - . .

~L3~

soluble at least to the extent employed in the emulsion. Accordingly the fluorochemical surfactant of formula (I) should have a solubility in the emulsion of at least 0.001 percent by wei&ht, preferably at least 0.004 percent by weight emulsion.

Preferably R~ is a straight or branched chain perfluoroaklyl group of 2 to 20 carbon atoms or mixtures thereof, or said perfluoroalkyl substituted by perfluoroalkoxy of 2 to 6 carbon atoms. Most perferably Rf is straight chain perfluoroalkyl of 4 to 18 carbon atoms or mixtures thereof.

Preferably n is 1 to 2, most preferably 1.

Lower, whenever used, means a carbon content of 1 to 6, especially 1 to 4 carbon atoms.

A may be selected from a wide array of linking groups known in the field of fluorochemical surfactants, preferably including a direct bond, an aliphatic, aryl or araliphatic group of up to about 40 carbon atoms, which may be unsubstituted or substituted by hydroxy, lower alkoxy, lower acyloxy, aryloxy, chloro, bromo, amido, or acrylamido, and wherein the aliphati, aryl or araliphatic g}oup may contain on either or both ends thereof a divalent linking moiety such as oxy, thio, sulfinyl, sulfonyl, sulfonamido, lower alkyl substituted sulfonamido, poly-lower alkoxylated sulfonamido, carboxamido, lower alkyl substituted carboxamido, lower alkoxylated carboxamido, poly-lower alkoxylated carboxamido, carbonyl, oxycarbonyl, carbonyloxy t amino, lower alkylamino or poly-lower alkoxylated amino, and where the linking group is alipha-tic or araliphatic, one or more of said linking moieties may interrupt said group, and wherein the valency of said organic linking group is equal to the sum of n plu9 m.

Preferably, m is l or 2, most preferably 1.
~ :
Preferably the group ~ is a nonionic group such as poly-lower alkyleneoxy substituted lower alkanol, or a lower alkyl ether, lower acryl ester, or a C6-C2~aryl ether or C6-C2~aryl ester thereof, or is anionic, such as ; ' ' ' .' ~, .
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carboxy, sulfonyloxy, sulfate, thiosulfate, thiosulfinate, borate, phosphate, or phosphonate anionic group or a salt thereof, including for example, the alkali metal, alkaline earth metal, ammonium, or amine salt thereof.

The fluorochemical surfactants useful in connnection with the present invention constitute a well known class of compounds, described as such in the known art, and many of which are readily commercially available from a variety of sources. Simila}ly, the hydrocarbon surfactants useful in combination with the instant fluorochemical surfactants constitute a well known class Df widely available compounds.

Preferred hydrocarbon surfactants are those which are nonionic or anionic or mixtures thereof. Especially preferred for use with the instant fluorochemical surfactants are those conventional hydrocarbons surfactants which ar0 known emulsifications promoting agents in the field of crude oil recovery.

For purposes of this application, a hydrocarbon surfactant is defined as a crude-oil in water emulsification promoting surfactant which is substantially devoid of oleophobic and hydrophobi~c fluoroaliphatic groups.
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While the upper limit of the amount of hydrocarbon sufactant, if any, employed is not critical, the use of a substantial excess over 2 percent by weight is generally both costly and without any substantial economic benefit to the use of an emulsion to reduce the viscosity of the crude.

In some cases~ the fluorochemical surfactant chosen exhibits a suficiently high interfacial tension that it cannot be used alone to form a stable emulsion, but must be employed in conjunction with an emulsion promoting hydrocarbon surfactant.

In general, the fluorochemical surfactant or mixture of fluorochemical and hydrocarbon surfactant should exhibit an interfacial tension between the crude oil and water~ in the amounts chosen, below 7, preferably ~below S, and most perferably below 3, at 20C.

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As stated above, the f1uorochemical surfactant must be soluble in the crude oil emulsified. As a result, conventional cationic fluorochemical surfactants are generally unsuitable for use in the present invention, since crude oils usually contain at least minor amounts of organic acid derivat iVH 5 .

The fluorochemical surfactant and the hydrocarbon surfactant are therefore anionic, nonionic or mixtures thereof.

Preferred hydrocarbon surfactants are those of the formula ( )n mQ (II) where R i9 an a~iphatic hydrocarbyl group of 6 to 24 carbon atoms, an aryl group of 6 to 14 carbon atoms, or an alkaryl group of 7 to 24 carbon atoms, and A, n, m and Q are as defined above.

When a hydrocarbon surfactant is employed in conjunction with the fluorochemical surfactant of formula I, the hydrocarbon surfactant is preferably employed in an amount of at least 0.001 %, more preferably between 0.004 % and most preferably between 0.01 and 1 % by weight based upon the weight of emulsion.

In a preferred embodiment, both the fluorochemical and the hydrocarbon surfactant are anionic or especially nonionlc.

Preferred hydrocaIbon surfactants include alkyl sulfonates of 6 ~to 24 carbon atoms; alkyl sulfates of 6 to 24 carbon atoms; poly-lower alkoxylated aliphatic alcohols, carboxamides, esters, amines, and su1fonamideD wherein the aliphatic group contains from 6 to 24 carbon atoms and the lower alkoxy units each contain 2 or 3 carbon atoms, with between 2 and 200 units; poly-lower alkoxylated alkyl phenols wherein the alkyl moiety contains between about 3 to 16 carbon atoms, the lower alkoxylated units each contain 2 or 3 carbon atoms, with between 6 and , .

. ~ ' ' 200 units, and polyoxamers, sucll as polyethoxylated polypropyleneoxide containing between about 6 to 200 ethoxylated units and 6 to 200 propylene oxide units.

Highly preferred are polyethoxylated alkyl phenols wherein the alkyl group contains 3 to 16 carbon atoms and between about 6 to 200 ethoxy units.

Suitable hydrocarbon surfactants include those preferred surfactants which are commercially available in bulk as crude oil water emulsifiers.

: Preferred nonionic groups of Q in formula I are selected from a group with the formula ,CH3 -(CH2CH20) -(CH2CHO)b-(CH2CH20)cH

wherein a is 2-40, b is 2-80 and c is 2-40.

Illustrative examples of fluorinated nonionic surfactants which can be used in the composition of this invention are:
C6FIICH2CH2SCH2ÇH ~ CH2CH20 ~ ÇHCH20~s~;~CHzCH20~H
: CH20H CH3 C6F~3CH2CH2SCH2ÇH-O(CH2CH2O~CH3 FC430 (3~f Company~
Zonyl FSN ~DuPont) Monflor 52 (I.C.I.
FC-170 (3M Company~

~ Illustrative examples of Rf-nonionics also include compounds more fully ;~ ; diaclosed~in the following patents: UDitad Sta$es: 1,925,555, 1,966,708, ~: 2,.160t852, 2,215:,386, 2,723,999, 3t621,059~ 3~721,700, 3~883,596, ~ ~ 3,952,075, German: 2,215,388, 2,230,3667 2~244,028S 2,250,718, 2S325,855 - ~ 2,:334,346~ 2,3377638, 2,501,239, British: 1,130,822, 1,.148,486, 1,155,607, 1,176,492, Belgium: 817,369, Nethe}lands: 7~009,980S
Japanese 75-157~275.
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Typical anionic groups of ~ are carboxylic, ammonium or metal carboxylate where the metal is an alkali or alkali earth metal, especially sodium, potassium, calcium, magnesium and the like, sulfinic or sulfonic acid group or ammonium or a metal salt thereof or phosphonic (OP(OH)2) or phosphoric (OP(OH)3? acid group or ammonium or metal salt thereof.

Illustrative examples of Rf-anionics which can be used in the compositions of this invention are the below shown acids and their alkali metal salts. The.patent numbers appearing in parenthesis are patenta which more fully disclose the represented class of compounds.

. . ~
Carboxylic Acids and Salts thereof .
RfCOOH Scholberg et al.
J. Phys. Chem. 57 923-5 (1~53) f 2)1-20 H (Ger. 1,916,699) RfO(CF2)2 20COOH ~Ger. 2,132,164) RfO~CF2)2 2o(CH2)2_2oCH (Ger. 2,132,164) RfO(CH2)l 20COOH (U.S. 3,409~647) RfSO2N(C2Hs)CH2COOH (U.S. 3,258,423) RfO~CF20)3CF2COOH (Fr. 1~531,902) RfOCF(CF3)CF2OCF2COOH (Fr. 1,537,922) Phosphonates, Phosphates~ Related Phosphoro Derivatives and Salts Thereof RfPO(OH)2 or (~Rf)2PO(OH) (Ger. 2,110,767) RfSO2N(Et)C2H40PO(OH)2 (Ger. 2~125,836) RfCH20PO(OH) (Ger. 2,158,661) CgF1sOC6H4CH2PO~OH)2 (Ger. 2,215,387) RfOC6H4CH2PO(OH)z (Ger. 2,230,366?
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Others (and Salts Thereof) RfSOzN(CH3)C?H4OSO3H (Ger. 1,621,107) RfC5H4OH (U.S. 3,475,333l Rf(CH2)l_20S2O3Na (Ger. 2.115,139) Rf(CH2)1 20SO2N(CH3)CH2CHzS2O3Na ~Ger. 2.115,139) RfSO2H ~U.S. 3,562,156) . .. . .
RfO(CF(CF3)CF2O)CF(CF3)CON(CH3)CHzCOOH (U.S. 3,798,265~
~CzFs)2(CF3)CCH2COOH (Brit. 1,176,493) C~F~gOC6H4CON(CH3~CH2COOH (Brit. 1,270,662) Rf(CH2)1 3SCH(CO0H)CHzCOOH ~U.S. 3,706,787) Rf(CH2)1_l2s~cH2)l_l7cOoH (Ger. 2,239,709;
U.S. 3,172,910) Sulfonic Acids and Salts thereof __ RfSO3H (~.S. 3,475,333) RfCsHL,SO3H (Ger. 2,134,973) ~( 2)1-20 3 (Ger. 2,309,365) RfSO2NHCH2C6H4SO3H (Ger. 2,315,326) Rso2N(cH3)~c2H4o)l-2oso3H ~S.A. 693,583) RfCH2CHzOCH2CH2CH2SO3H ~Can. 842,252) RfOC6HI,SO3H ~Ger. 2,230,366) C~zF23OC6HI~SO3H ~Ger. 2,240,263) (CzFs)3CO(CH2~3SO3H (Brit. 1,153,854) CF3(C2Fs)2CO~CH2~2SO3H ~Brit. 1,153,854) ~C2Fs)z(CF3)CCH=C~CF3)SO3H ~Brit. 1,206,5g6) RfOCF~CF3)CF2OCF~CF3)CONHCH2SO3H ~U~S. 3,798,265~
:: :
The amphoteric fluorinated surfactants included in the composition of the present invention can be represented by the formula:
R -R'-S-~CHz) -CH-COOH
f Y CHz-COX-Q

and its isomer ` ::

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RfR'-S-(CH7) -Ç-COX-Q
Y CH ~ COOH
o Rf-R'-S-(CH~)y ~H \N 0 H ~--C~
o wherein Rf is straight or branched chain perfluoroalkyl of 3 to 1~ carbon atoms or said perfluoroalkyl substituted by perfluoroalkoxy of 2 to 6 carbon atoms, R' i8 branched or straight chain alkylene of 1 to 12 carbon atoms, alkylenethioalkylene of 2 to 12 carbon atoms, alkyleneoxyalkylene of 2 to 12 carbon atoms or alkyleneiminoalkylene of 2 to 12 carbon atoms where the nitrogen atom contains as a third substituent, hydrogen or alkyl of 1 to 6 carbon atoms, y is 1 or zero X is oxygen or -NR, wherein R is hydrogen, lower alkyl of 1 to 6 carbon atoms, hydroxy-alkyl of 1 to 6 carbon atoms, or R together with Q forms a piperazine ring, and Q is a nitrogen containing group selected from 1. an aliphatic amino group selected from ,R3 -(R~) -N' (la) +/R
-(R2~k-N\ Rs A- and ~lb~

-(R2)k- ~- G (lc) ~, wherein :~ R~ is a linear or branched alkylene of 2 to 12 carbon atoms, oxygen or sulfur interrupted linear or branched alkylene of up to 60 carbon atoms, :: or hydroxyl substituted alkylene. Preferably R~ is a straight chain or ~ branched alkylene of 2 to 5 carbon atoms;
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k is 1 or zero, with the provision, that if X ls oxygen k is l;
R3 and R4 are independently of each other hydrogen, alkyl, alkenyl or substituted alkyl, or alkenyl, each oE 1 to 20 carbon atoms; phenyl, alkyl or halogen substituted phenyl of 6 to 20 carbon atoms, polyethoxy or polypropoxy of 2 to 20 alkoxy units, with the proviso that if X is oxygen7 R3 and R4 are not hydrogen. The alkyl or alkenyl substituents can be hydroxyl, carboxyl, halogen, alkylene dialkylphosphonate such as methyl-diethylphosphonate or a group -N/

Phenyl substituents can be methyl, halogen or hydroxyl. Preferably R3 and R~ are lower alkyl groups of 1 to 4 carbon~3.

A- is any anion which forms ammonium salt of the formula NH~+A-.
Anion A- can be derived f}om alkyl halides, benzene or chlorobenzene sulfonate esters of alkyl alcohols and methyl and ethyl sulfates. A- is preferably Cl- or CH3CH2OSO3-.
Rs is hydrogen7 an alkyl group or hydroxylalkyl group, aralkyl or groups of the formula -(CH2~ -COO-alkyl, said alkyl group having 1 to 1~ carbons. Preferably, Rs is methyl, ethyl, propyl, butyl or benzyl.
G- is selected from the groups -(CH2)n-COO7 -1CH2~ 3SO3 7 ~, -,CH-COO and -,C,-COO

' where n is 1 to 5 2. cyclic amino groups selected from 2_ ~ ~2a) -R2- ~ A and ~2b~

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~ R2 ~ ~2c~

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- 12 ~

wherein Y is a diradical group of the formulae;

~(CH 2 ) 4 ~
~(CH ,7 ) 5 ~
~(CH 2 .) 2 ~0~ ( CH 2 ) 2 ~

-(cH2)-clH-~~(cH2 wherein R2, Rs, A~ and G~ are as defined above, R7 and R8 are independent hydrogen~ a lower alkyl or hvdroxy-lower alkyl group of 1 to 6 carbon atoms, with the provision, that if X is oxygen, R8 cannot be hydrogen.

3. Aromatic amino groups selected from ~ Za ( )k ~ ~. (3a) a R2~k t il A and ~3b) ~/
: Rs a R2l ~ Ij ~3c) ; ` ~ 4~ fus~d-ring aro~atic amino group selected from R~ 4a) ': ::: :

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~3~5~

Z Zb -(R2)k t il i A ~4b~
~5 and Z Z
~, \ /
-(E2:)k----+i1 I ~4c~

wherein Z is halogen or methyl, a and b are an inte~er from 0-3; and 5. a heterocyclic amino group of the formula 5a. -~R2)k-E
5b. -(R2)k-E -RsA
5c. -~R2~k-E -G

where k is one or zero and E is selected from N-hydroxyalkyl or N-amino-alkyl, substituted pyrrole~
pyrazole, imidazole, triazole, indole or indazole, hydroxyalkyl and aminoalkyl ring-substituted pyridazine, pyrimidino, pyrazino or ~uinoxalino.

Illustrative examples of amphoteric fluorinated surfactants are:

: N-~3-(dimethylamino)propyl]-2,(3)-(1,1,2,2-tetrahydroperfluoroalkyl-thio~succinamic acid~ ~
N-methyl-N-(2'-N,N'-dimethylaminoethyl)-2-(3)-(1,1,2,2-tetrahydroper-fluoroalkylthiojsuccinamic acid~
N-(2-timethylaminosthyl~-2,(3~ 1,2,2'-tetrahydroperfluoroalkyl-thio~succinamic acit, 2(3~-(1,1,2,2-tetrahydroperfluorodecylthio.)succinic acid-mono-2-N,N-methyl~aminoethyllester, : ~:

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~ 13~5C~ 1 2-(3)-(1,1,2,2-tetrahydroperfluorodecylthio)succinic acid-mono-(2'-quinolino-ethyl)ester, N,N'-bis[(n-propyl-3)-~1,1,2,2-tetrahydroperEluorooctylthio)succinamic monoamido]piperazine, N-~3-(dimethylamino)propyl]-2~(3)-(heptafluoroisopropoxy-~ 2~2-tetra hydroperfluoroalkylthio)succinamic acid, 2-~ 2,2-tetrahydroperfluorooctylthio)N-~3-(dimethylamine~propyl¦-2-methyl succina~ic acid, N-ethyl--N-(2'-N',N'-dimethylaminoethyl)-2,(3)-(1~1,2,2-tetrahydroper-fluoroalkylthio)succinamic acid, N-~3-(dimethylamino)propyl]-2~3)-(1,1,2,2-tetrahydroperfluorooctyl-thio)succinamic acid, and N-methyl-N-(2'-N'N'-dimethylaminopropyl)-2,(3)-(1,1,2,2-tetrahydroper-fluoroalkylthio)succinamic acid, N-[3-(dimethylamino)propyl~-2(3)-(1,1~2,2-tetrahydroperfluorodecyl-thio)succinamic acid, and N-[3-(dimethylamino)propyl]-2(3)-(1,1,2,2-tetrahydroperfluorododecyl-thio)succinamic acid, Xeaction product of N-~3-(dimethylamino)propyl]-](3)-(1,1,2,2-tetrahydroperfluorodecyl-thio)succinamic acid and propane sultone, Reaction product of N-[3-(dimethylamino)propyll-2(3)-(1,.1,2,2-tetrahydroperfluorooctyl-thio~succinamic acid and chloroacetic acid, or Zonyl FSB (DuPont).

The emulsions of the present invention are characterized both by 1) their stability to breakdown or inversion even under conditions of turbulent flow up to tsmperatures of at least about 50C, and 2~ the ease at which ths emulsion can be broken cleanly to yield the crude oil and water at temperatures in excess of 50C, preferably between 55 and 75C. The ease at which the emulsion can be clearly broken at elevated temperatures is unsxpected and surprising, and is highly advantagsous. For sxampls, there is generally no need for the addition of de-emulsification materials, and ths ssparatsd aqueous phass can therefore be simply recycled if desired or convsnient.

A further embodi~ent of the present invention relates to a method of transporting a viscous crude oil by converting the oil into an aqueous crude oil in water low viscosity emulsion by contacting said oil with an aqueous solution containing tile requisite amounts of fluorochemical surfactant, optionally with hydrocarbon surfactant, under sufficiently turbulent conditions to induce emulsion formation, and transporting the oil in the form of the resulting emulsion. Whsre the interfacial tension is sufficiently low, e.g. below 2, emulsification may occur spontaneously.

After the oil emulsion is transported to a convenient site, e.g. by pipeline, the emulsion is then broken and the crude oil recovered for further processing by heating the eMulsion in excess of 50.

The followin~ test methods and examples are given for illustrative purposes. All parts are by weight unless otherwise indicated.

Description of laboratory test method 1 Control:
The crude oil is placed in a closed container. The container and its contents are placed in a draft oven at 50C for 15 minutes. The container is then opened and the oil is sheared using a Polytron~ mixer at high speed for one minute to o~tain a homogeneous oil. Viscosity measu}ements are conducted using the Brookfield Viscometer Model RVF equipped with spindle 4. The spindle is attached to the viscometer and lowered into the contents of the container. The oil is stirred at 20 RPM for 5 minutes.
The temperature is recorded and the viscosity is measured at 20 and 10 RPM.

Doped Sample:
Ths above procedure is repeated with the addition of surfactants and water to fo}m an emulsion. An oil-soluble surfactant is added to the oil ~ ~ :
in the container. Water~ containing a wate}-soluble surfactant at a predete}mined concentration, i9 added to the oil at a certain percent ratio. The thermal treatment and viscosity measurements are conducted ; ~ according to the above p}ocedure.

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Description_ f laboratory test method 2 A Fann 35AISR12 Viscometer equipped with a closed-end rotor cup~ a hollow bob, a double-wall circulating cup and a circulating bath i8 emplo~ed for viscosity measurements. Approximatively 22.5 g of oil are placed directly into the closed-end rotor cup. To this are added 250 ppm of an oil-soluble surfactant followed by 7.5 g of a 0.1 % water solution containing a water-soluble surfactant. The closed-end rotor cup and its contents are weighted, placed in a draft oven at 50DC for 15 minutes and then reweighed to assure zero weight loss. The rotor cup is attached to the viscometer and lowered into the double-wall circulating cup which contains water as a heating medium. The temperature is controlled by a circulating bath that is connected to the jacket of the double-wall circu1ating cup. The doped oil/water mixture is allowed mix and e~uilibrate at 25VC for S minutes at 300 RPM. The viscosity is measured at 300, 200 and 100 RPM at 25C. The emulsion mixture is then sheared at 600 RPM (shear rate = 1021 sec ~ for 5 minutes and the viscosity is remeasured. The viscosity measurments are repeated at higher temperatures.

Examples 1-6 The examples illustrate the viscosity reduction of c}ude oil obtained by the addition of a surfactant package containing one o} more fluorinated compounds to an oillwater mixture. A sample of Canadian crude oil alone (control) and a combination of Canadian crude (3 parts) doped with 250 ppm of compound A and water (1 part~ doped with 250 ppm of Compound B
are prepared and the viscosities are measured according to Laboratory ~ Test Method 1. The }esults a}e summarized in Table I.

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O O
~ rl O rl ~ ~ a~
P~
.. __ O O 0 3 0 0 o o o O O O O O
U .^~ O o o o U~ o o o U~ o U~ o o o . ~ ~t `O CO ci~ ~ ~ ~t ~ ~ C~ ~ ~`I ~7 d ~ __ . ~
~ 0 0 0 0 0 0 o o 0 0 0 0 0 0 I::e ~1 ~ ~ ~ ~ ~ ~ ~ ~ _ ~ ~ ~ ~ 0 ~ .. . ~ . _ .. ~ ~
~ ~ O O oo ~

_ _._ ._ ._ __ , . .____ V
~0~
:C ~ .
.~ U

~ a ~ ~ - a~

~ _ æ ~ : ~ ~ o ~
J- o, I ~
o :~
'~
~ 0 ~5 : ~ i ~: ~ 4 0 ~ ~i ~ ~1 1 ) N C~ I ~1 11'1 0 ~ 1.1 P.-S ~ X X C`l ~
~ ~ ~ ~ c c~
c~ x O ~ g 8 oo ,1 ~ ~ 0 1~ ~ 1 3 ~rl rl `~ e O
o / ~ O ~ p~
:: __ ~._ _ _ J.. l PA ~1 ~
H ~, r~ 3) ~3 8 ~ ~ . . _ __ ___ A _ ________ . . ~ ~¦ ~r) ~ In :: :
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5~ 1 Example 7-8 _ The examples illustrate the reduction of crude oil viscosity obtained by the addition of a surfactant package of fluorlnated compounds to an oil containing water. The viscosity of Vene~uelan crude oil which contains 15 % water is measured. To tllis crude is added 500 ppm of Compound C and 500 ppm of Compound D. The viscosities are then remeasured. The results are tabulated in Table II.

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1~05~91 1 _ .. . .
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u ~ a ~ ~0 ~ ~ 3 0 '1:1 ? ~
.. _ .~ O
oP, 00~ 00 ~0 ~ CO ~ ~ ~ aD
__ . _ ~ 1::
~o ~
P~ ~ ~ C~ ~ C~
~i 3 ~ ~c~l ~:
R ~ o rd ~

UO~ O ~
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,/ C~ X~
O

' O E O R ~

. O ~3~ O
c~ æ c~ ~ ~ ~ ~
~ _ _ _ _1 ~
P- ~ ~
~ rd ~ _, ~ ~ i .

~ : w Iq o D D 1~

~ ~ ~ ~C: 4~ 0 ~
~ ¢ C~, ~ ~0'~'~
1:
O ~ ' D~
1:: El 1:: ~ ' 3 ~ P~
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5~11 1 Example 9 The example demol~strates the superiority of a fluorinated surfactant over a hydrocarbon surfactant in maintaining a stable oil-in-water emulsion at higher temperatures. Two oil/water mixtures are prepared and doped according to Laboratory Test Method 2. One sample contains a hydrocarbon surfactant and consists of Canadian crude (3 parts? doped with 250 ppm Triton X-100~1 mixed with water ~1 part). The other sample is similar except that it also contains 250 ppm of a fluorinated surfactant, compound B from ~xample 1, in the water portion. The viscosity measurements are conducted as previously described (without high shearing). A sharp decrease in viscosity is an indicative of an emulsion split. The results are summari~ed in Table III.
Table III
.. _. . . _ . . ...... _ . . __ Concen- Tempera- Viscosit ~cPs) Surfactant Package tration ture (C) 300 RPM 100 RPM
.. . . _ _ _ Triton~ X-1001250 ppm 29 1 28 30 40.5 18 21 50.6 9 (emulsion9 (emulsion _ _ _split~ split) Triton~ X-1001/ 250 ppm 25.5 30 27 Compound Beach 30.6 30 24 from Example 1 50 6 223 21 70.0 14 (emulsion9 (emulsion _ _ _ split) split) Triton~ X-1001/ 100 ppm/ 25.3 30 28 Compound B 100 ppm 29.7 28 ~ 24 from Example 1 40.0 25 21 50.2 23 20 70.0 12 (emulsion9 ~emulsion ~ __split) split) ';
1 from Rohm and Haas Company, believed to contain alkylaryl polyester alcohols.

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Example 10 The example illustrates the stability oE the oil-in-water emulsion containing a Eluorochemical surfactant, even after extensive shearing. A
combination of Canadian crude (3 parts) doped with 250 ppm Triton~ X-100 and water (1 part~ containing 250 ppm of Compound B from Example 1 is prepared. The viscosity is measured before and after shearing (shear rate = 1021 sec 1) as described in Laboratory Test Method 2. The consistency of the sheared emulsion viscosity with the initial emulsion viscosity at each temperature is indicative of a stable oil-in-water emulsion. The results are sum~arized in Table IV.

1 from Rohm and Haas Company, believed to contain alkylaryl polyether alcohols .

Table IV
Tempe- 300 RPM l 200 RPM l 100 RPM
{ature .__ .. . _ I . I - -------- -C) Initial Sheared ¦Initial Sheared ¦Initial Sheared Viscosity Viscosity2 IViscosity Viscosity2 IViscosity Viscosity2 (cPs) (cPs) I (cPs) (cPs) I ~cPs~ (cPs) . I . . ~ - I . _ 25.5 37 35 1 30 30 1 27 27 3U.6 30 28 1 27 24 1 24 21 40.8 27 24 1 26 21 1 21 18 50.6 23 22 1 25 22 1 21 21 2 Oil/water mixture was sheared for 5 minutes, shear rate = 1021 sec 1.

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Claims (10)

1. A crude oil in water emulsion, which is stable to both breakdown and phase inversion up to at least about 50°C, said emulsion containing an effective, soluble, emulsion stabilizing amount of a fluorochemical surfactant of the formula (Rf)nAmQ (I) wherein Rf is an inert, stable, oleophobic and hydrophobic fluoroaliphatic group having up to 20 carbon atoms;
n is an integer from 1 to 3;
A is a direct bond or an organic linking group and is covalently bonded to both Rf and Q;
Q is an anionic, nonionic or amphoteric group; and m is an integer from 1 to 3;
wherein the amount by weight of said fluorochemical surfactant present in said emulsion being between 0.001 and 1 % by weight of said emulsion, in the presence or absence of up to 2 % by weight of a crude oil emulsion promoting hydrocarbon surfactant, with the proviso that at least 0.005 %
by weight total fluorochemical and hydrocarbon surfactant is present, based upon the weight of emulsion, and wherein said emulsion contains about 15 to 90 percent by weight water, based upon the weight of emulsion, such that the viscosity of the emulsion is less than 50 % of the viscosity of said crude oil.

2. An emulsion according to claim 1, wherein the amount of water present is between 20 to 70 % by weight, based upon the weight of emulsion.

3. An emulsion according to claim 17 wherein Rf in formula I is straight chain perfluoroalkyl of 4 to 18 carbon atoms or mixtures thereof.

4. An emulsion according to claim 4, wherein in formula I n is 1, and m is 1.

5. An emulsion according to claim 1, wherein the fluorochemical surfactant is anionic or nonionic.

6. An emulsion according to claim 1, wherein the hydrocarbon surfactant is employed in an amount of at least 0.001 %.

7. An emulsion according to claim 1, wherein the hydrocarbon surfactant is of the formula (R)nAmQ (II) wherein R is an aliphatic hydrocarbyl group of 6 to 24 carbon atoms, an aryl group of 6 to 14 carbon atoms, or an alkaryl group of 7 to 24 carbon atoms, A is a direct bond or an organic linking group and is covalently bonded to both R and Q;
Q is an anionic, nonionic or amphoteric group;
n is from 1 to 3, and m is from 1 to 3.

8. An emulsion according to claim 1, which spontaneously breaks down into an aqueous and crude oil phase at a temperature between 55 and 75°C.

9. A method of transporting a normally viscous crude oil by converting said oil into an aqueous emulsion according to claim 1 by the addition of water and said fluorochemical surfactant and optionally said hydrocarbon surfactant under sufficiently turbulent conditions to induce crude oil in water emulsion formation, transporting said oil in the form of said emulsion and breaking said emulsion to recover said crude oil by heating the emulsion in excess of 50°C.

10. A method according to claim 9, wherein the emulsion is broken by heating the emulsion between about 55°C and about 75°C.

FO 7.3/