EP0292427A1 - Crude oil emulsion containing a fluorinated surfactant - Google Patents

Abstract

The transportable emulsion of crude oil and water, which is stable up to 50 DEG C against phase separation and phase transformation, contains an effective quantity of a soluble anionic, nonionic or amphoteric fluorinated surfactant which stabilises the emulsion and, if appropriate, of a hydrocarbon surfactant; it is used in a process for transporting crude oil in the form of such an emulsion.

Description

The invention relates to an improved method for pumping and / or transporting viscous crude oils, in which an effective fluorine-containing surfactant is added to a crude oil emulsion in the presence of water and a low-viscosity emulsion is formed from crude oil and water.

Viscosity often limits the amount of crude that can be extracted from a well. For example, when oil is extracted from a borehole with a string of a pump string, the resistance exerted on the string by the viscosity of the crude oil slows down the free fall caused by gravity on the downward stroke. The resistance also acts on the upward stroke, reduces the oil flow through the production pipe and increases the force required to lift the crude oil and strand. For example, if the crude oil is very viscous (e.g. the Boscan field in Venezuela), the strength of the pump rod limits the depth at which a pump can still be used. Alternatively, hydraulic pumps can be placed at the bottom of the borehole. Overcoming the viscosity resistance then requires a high oil pressure and therefore high pump outputs.

The underground pump usually provides the pressure necessary to pump the oil produced from the end of the borehole to the collection tanks on the surface. If the viscosity is high, the use of extra strong equipment at the end of the borehole (seals, sealing rings, thick pipe walls) may be necessary to withstand the pressure to convey the viscous crude oil from the end of the borehole to the storage tanks.

It has been proposed to lower the viscosity of heavy crude oils prior to pumping by using low viscosity crude oil, light oil, kerosene and the like to dilute the produced crude oil downhole introduces cavity. In drill holes with piston pumps, the string of the pump string is usually surrounded with an extra pipe. Low-viscosity oil is pumped down through this tube, so that the strand is surrounded by low-viscosity oil. The added light oil then mixes with the viscous crude near the pump run valve to dilute the portion of the crude that is pumped downhole through the ring formed by the inner pipe and production pipe. Alternatively, low-viscosity oil can be pumped down through a hollow pump rod and the diluted crude oil can be pumped through the ring between the hollow pump rod and the tube.

The crude oil available in this way has a reduced viscosity and is easier to transport. The disadvantage, however, is that the diluents are expensive and not always available, and they have to be separated from the diluted crude oil.

The viscosity of heavy crude oils can also be reduced by transport at elevated temperatures. This method is very expensive because the decrease in viscosity per degree of temperature increase is very low. The heating equipment and performance requirements are expensive.

Another way to reduce the viscosity of asphaltic crude oils is to form low-viscosity emulsions from crude oil and water with the addition of hydrocarbon surfactants (see, for example, US Pat. No. 3,943,954, US Pat. No. 4,265,264, US Pat. No. 4,429,554 and US Pat. No. 4,239,052). . Such emulsions generally contain less water, for example 10-40% water, which must be removed. Separation is not always easy and large amounts of water contaminated with oil result. High temperatures are also required to separate the water, which means additional expenses. Such emulsions become unstable at critical flow rates and then form highly viscous emulsions, so that the pumping capacity decreases.

The invention relates to an emulsion of crude oil and water which contains 0.001 to 1% by weight, based on the weight of the emulsion, of a soluble fluorine-containing surfactant of the formula I.
(R _f ) _n A _m Q (I),
wherein
R _{f represents} an inert, stable, oleophobic and hydrophobic fluoroaliphatic group with up to 20 C atoms,
n is a number from 1 to 3,
A represents a direct bond or an organic bridging group which is covalently bonded to R _f and Q,
Q represents an anionic, nonionic or amphoteric group, and
m is a number from 1 to 3,
wherein the emulsion contains 0 to 2% by weight of an emulsion-promoting hydrocarbon surfactant and at least 0.005% by weight of fluorine-containing surfactant and hydrocarbon surfactant are present, and the emulsion contains 15 to 90% by weight of water, based on the emulsion, so that the viscosity the emulsion is less than 50% of the viscosity of the crude oil.

The emulsion preferably contains 20 to 70% by weight, particularly 25 to 60% by weight, of water. For example, are drinking water, salt water or brackish water. Crude oils often contain considerable amounts of water themselves. In general, the type of water is not critical to the formation of the emulsion.

The type of fluorine-containing surfactant used is generally not critical. However, it should be compatible with the emulsified crude oil. The fluorine-containing surfactant is preferably soluble in the emulsion at least in the amount used. Accordingly, the fluorine-containing surfactant of the formula I has a solubility of preferably at least 0.001, particularly 0.004% by weight in the emulsion.

R _f preferably represents linear or branched C₂-C₂₀ perfluoroalkyl or mixtures of such alkyl groups, which can be substituted with C₂-C₆-perfluoroalkoxy. R _f is particularly preferably linear C₄-C₁₈ perfluoroalkyl or a mixture of such perfluoroalkyl groups.

N is preferably 1 or 2, in particular 1.

Wherever used, low means a carbon content of 1 to 6, especially 1 to 4 carbon atoms.

A can be selected from a wide range of bridging groups which are known per se for fluorine-containing surfactants. A is preferably a direct bond, aryl, an aliphatic or araliphatic group having up to 40 C atoms, which is unsubstituted or substituted by hydroxy, lower alkoxy, lower aryloxy, aryloxy, chlorine, bromine, amido or acrylamido, and in which the aryl , the aliphatic or araliphatic group at one or both ends may contain a divalent connecting group, such as Oxy, thio, sulfinyl, sulfonyl, sulfonamido, sulfonamido substituted with lower alkyl, poly (lower alkoxylated) sulfonamido, carboxamido, carboxamido substituted with lower alkyl, lower alkoxylated carboxamido, poly (lower alkoxylated) carboxamido, carbonyl, oxycarbonyl, carbonyloxy, amino, lower alkamino or poly ) Amino, and wherein the aliphatic or araliphatic bridging group may be interrupted by one or more of said connecting group, and wherein the valence of said organic bridging group is equal to the sum of n + m.

M is preferably 1 or 2, especially 1.

Q is preferably a nonionic group, e.g. lower alkanol, lower alkyl ether, lower acrylic ester, C₆-C₂₀ aryl ether or a C₆-C₂₀ aryl ester thereof substituted by poly (lower alkyleneoxy), or by an anionic group, for example carboxy, sulfonyloxy, sulfate, thiosulfate, thiosulfinate, borate, phosphate, phosphanate, or salts thereof such as alkali metal, alkaline earth metal, ammonium or amino salts.

The fluorine-containing surfactants used according to the invention are a class of compounds known from the literature and many are commercially available from different manufacturers. Likewise, hydrocarbon surfactants to be used in accordance with the invention together with fluorine-containing surfactants represent a well-known class of commercially available compounds.

Preferred hydrocarbon surfactants are nonionic or anionic or mixtures of such surfactants. According to the invention, preference is given to using those customary hydrocarbon surfactants with the fluorine-containing surfactants which are emulsion-promoting agents known in the field of oil production.

According to the application, a hydrocarbon surfactant is defined as a crude oil-water-promoting surfactant that contains essentially no oleophobic and hydrophobic fluoroaliphatic groups.

If a hydrocarbon surfactant is used, the maximum amount is not critical. The use of an excess of more than 2% by weight is generally expensive and has no significant economic advantage in reducing the viscosity of the crude oil.

In some cases, the selected fluorosurfactant can have a high surface tension so that it cannot be used alone to form a stable emulsion. It is then expediently used together with an emulsion-promoting hydrocarbon surfactant.

In general, the fluorine-containing surfactant or its mixtures with hydrocarbon surfactants has a surface tension between crude oil and water, depending on the amount added, of less than 7, preferably less than 5 and especially less than 3 at 20 ° C.

As already mentioned, the fluorine-containing surfactants must be soluble in the emulsified crude oil. Conventional cationic fluorine-containing surfactants are therefore generally unsuitable for the use according to the invention, since crude oils usually contain at least small amounts of organic acid derivatives. The fluorine-containing surfactant and the hydrocarbon surfactant are therefore anionic, nonionic or mixtures thereof.

Preferred hydrocarbon surfactants are those of the formula II
(R) _n A _m Q (II),
wherein R is an aliphatic hydrocarbon radical having 6 to 24 carbon atoms, C₆-C₁₄ aryl or C₇-C₂₄ alkaryl and A, n, m, and Q have the meanings given above.

If a hydrocarbon surfactant of the formula II is used together with a fluorine-containing surfactant of the formula I, the hydrocarbon surfactant is preferably used in an amount of at least 0.001% by weight, in particular between 0.004% by weight and in particular between 0.01 and 1% by weight. -%, based on the emulsion used.

In a preferred embodiment, the hydrocarbon surfactant and the fluorine-containing surfactant are anionic and particularly nonionic.

Preferred hydrocarbon surfactants include, for example:
C₆-C₂₄ alkyl sulfonate; C₆-C₂₄ alkyl sulfate; polyalkoxylated aliphatic C₆-C₂₄ alcohols, C₃-C₁₆ alkylphenols, carboxamides, esters, amines and sulfonamides, in which the alkoxy group contains 2 or 3 carbon atoms and poly represents 2 to 200, preferably 6-200, units; and polyoxamers such as polyethoxylated polypropylene oxides containing between 6 and 200 ethoxy units and between 6 and 200 propyleneoxy units. Polyethoxylated C₃-C₁₆ alkylphenols with 6 to 20 ethoxy units are particularly preferred.

Particularly preferred hydrocarbon surfactants are those which are commercially available in large quantities as emulsifiers for oil / water mixtures.

worin a 2-40, b 2-80 und c 2-40 sind.Preferred nonionic groups Q in formula I correspond to the formula

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

FC430 (3M Company),
Zonyl FSN (DuPont),
Monflor 52 (I.C.I.),
FC-170 (3M Company).Examples of fluorine-containing nonionic surfactants to be used according to the invention are:

FC430 (3M Company),
Zonyl FSN (DuPont),
Monflor 52 (ICI),
FC-170 (3M Company).

Other suitable fluorine-containing surfactants are e.g. described in U.S. Patents: 1,925,555; 1,966,708; 2,160,852; 2,215,386; 2,723,999; 3,621,059; 3,721,700; 3,883,596; 3,952,075; German Offenlegungsschriften: 2,215,388; 2,230,366; 2,244,028; 2,250,718; 2,325,855; 2,334,346; 2,337,638; 2,501,239; British patents: 1,130,822; 1,148,486; 1,155,607; 1,176,492; BE-PS 817,369; NL-OS 7,009,980 and JP-OS 75-157,275.

Preferred anionic groups Q are e.g. Carboxyl and ammonium or metal carboxylates, in which the metal represents an alkali or alkaline earth metal, in particular Na, K, Ca and Mg; or sulfinic or sulfonic acid groups or corresponding ammonium or metal salts; or phosphonic (OP (OH) ₂) or phosphoric acid groups (OP (OH) ₃) or corresponding ammonium or metal salts.

Examples of fluorine-containing anionic surfactants to be used according to the invention are the acids given in the table below and corresponding alkali metal salts. If numbers of patent publications are in parentheses, the publications describe corresponding classes of compounds. R _f stands for perfluoroalkyl.

und dessen Isomeren

sowie

dargestellt werden, worin
R_f lineares oder verzweigtes, unsubstituiertes oder mit C₂-C₆-Perfluor­alkoxy substituiertes C₃-C₁₈-Perfluoralkyl bedeutet,
R′ lineares oder verzweigtes C₁-C₁₂-Alkylen, C₂-C₁₂-Alkylenthioalkylen, C₂-C₁₂-Alkylenoxyalkylen oder C₂-C₁₂-Alkyleniminoalkylen darstellt, wobei das N-Atom als dritten Substituenten H oder C₁-C₆-Alkyl enthält,
y für 0 oder 1 steht,
X -O- oder -NR bedeutet, worin R H, C₁-C₆-Alkyl, C₁-C₆-Hydroxyalkyl be­deutet oder R zusammen mit Q einen Piperazinring bildet, und
Q einen Stickstoff enthaltende Gruppe bedeutet, ausgewählt aus:

• 1. einer aliphatischen Aminogruppe der Formeln
  
  worin
  R² lineares oder verzweigtes C₂-C₁₂-Alkylen, mit -O- oder -S- unter­brochenes lineares oder verzweigtes Alkylen mit bis zu 60 C-Atomen, oder mit Hydroxyl substituiertes Alkylen, bevorzugt lineares oder verzweigtes C₂-C₅-Alkylen bedeutet,
  k 1 oder 2 ist, mit der Massgabe, dass k 1 ist, wenn X für -O- steht,
  R³ und R⁴ unabhängig voneinander H, unsubstituiertes oder substituiertes C₁-C₂₀-Alkyl oder C₂-C₂₀-Alkenyl, unsubstituiertes oder mit Hydroxyl, C₁-C₁₄-Alkyl oder Halogen substituiertes Phenyl, oder Polyethoxy oder Polypropoxy mit 2 bis 20 wiederkehrenden Einheiten bedeuten, mit der Massgabe, dass R³ und R⁴ nicht H bedeuten, wenn X Sauerstoff ist; wobei Alkyl- und Alkenylsubstituenten bevorzugt Hydroxyl, Carboxyl, Halogen, Alkylendialkylphosphonat wie z.B. Methyl-diethylphosphonat, oder die Gruppe -NR³R⁴ sind; bevorzugte Phenylsubstituenten, Methyl, Halogen oder Hydroxyl; und wobei R³ und R⁴ bevorzugt C₁-C₄-Alkyl darstellen;
  A für ein Anion steht, das ein Ammoniumsalz der Formel NH₄⁺A⁻ bildet, wobei A bevorzugt von Alkylhalogeniden, Benzol- oder Chlorbenzolsulfonsäureestern von Alkanolen und Methyl- und Ethylsulfaten abgeleitet ist, und A insbesondere Cl- oder CH₃CH₂OSO₂- ist;
  R⁵ für H, Alkyl, Hydroxyalkyl, Aralkyl oder -(CH₂)_n-COO-C₁-C₁₈-Alkyl mit n gleich 1 bis 5 steht, wobei R⁵ bevorzugt Methyl, Ethyl, Propyl, Butyl oder Benzyl;
  G bedeutet die Gruppen
  -(CH₂)_n-COO⁻ mit n gleich 1 bis 5, -(CH₂)₃SO₃⁻,
  
• 2. Cyclische Aminogruppen der Formeln
  
  worin Y ein zweiwertiger Rest der Formeln
  -(CH₂)₄- , -(CH₂)₅- , - (CH₂)₂-O-(CH₂)₂- und -(CH₂)--(CH₂ wobei R², R⁵, A⁻ und G⁻ wie zuvor definiert sind, und
  R⁷ und R⁸ unabhängig voneinander H, C₁-C₆-Alkyl oder C₁-C₆-Hydroxyalkyl sind, mit der Massgabe, dass R⁸ nicht H ist, wenn X für Sauerstoff steht;
• 3. Aromatischen Aminogruppen der Formeln
  
  und
• 4. Kondensierte aromatische Gruppen der Formeln
  
  und
• 5. eine heterocyclische Aminogruppe der Formeln
  -(R²)_k-E (5a), -(R²)_k-E⁺-R⁵A⁻ (5b) und -(R²)_k-E⁺-G⁻ (5c),
  worin Z Halogen oder Methyl ist, a und b eine Zahl von 0-3 sind, k 0 oder 1 darstellt, und E mit Hydroxyalkyl oder Alkyl N-substituiertes Pyrrol, Pyrazol, Imidazol, Triazol, Indol oder Imidazol, oder für mit Aminoalkyl- oder Hydroxyalkyl substituiertes Pyridazin, Pyrimidin, Pyrazin oder Chinoxalin steht.

Amphoteric fluorine-containing surfactants to be used according to the invention can be represented by the formulas

and its isomers

such as

are shown in what
R _{f is} linear or branched, unsubstituted or substituted by C₂-C₆-perfluoroalkoxy C₃-C₁₈-perfluoroalkyl,
R ′ represents linear or branched C₁-C₁₂ alkylene, C₂-C₁₂ alkylene thioalkylene, C₂-C₁₂ alkyleneoxyalkylene or C₂-C₁₂ alkyleneiminoalkylene, where the N atom contains H or C₁-C₆-alkyl as third substituent,
y represents 0 or 1,
X represents -O- or -NR, where RH, C₁-C₆-alkyl, C₁-C₆-hydroxyalkyl means or R together with Q forms a piperazine ring, and
Q represents a nitrogen-containing group selected from:

• 1. an aliphatic amino group of the formulas
  
  wherein
  R² is linear or branched C₂-C₁₂ alkylene, linear or branched alkylene with up to 60 C atoms interrupted by -O- or -S-, or alkylene substituted by hydroxyl, preferably linear or branched C₂-C₅ alkylene,
  k is 1 or 2, with the proviso that k is 1 when X is -O-,
  R³ and R⁴ independently of one another are H, unsubstituted or substituted C₁-C₂₀-alkyl or C₂-C₂₀-alkenyl, unsubstituted or substituted by hydroxyl, C₁-C₁₄-alkyl or halogen, or polyethoxy or polypropoxy having 2 to 20 repeating units, with provided that R³ and R⁴ are not H when X is oxygen; where alkyl and alkenyl substituents are preferably hydroxyl, carboxyl, halogen, alkylene dialkylphosphonate such as methyl diethylphosphonate, or the group -NR³R⁴; preferred phenyl substituents, methyl, halogen or hydroxyl; and wherein R³ and R⁴ are preferably C₁-C₄ alkyl;
  A represents an anion which forms an ammonium salt of the formula NH₄⁺A⁻, where A is preferably derived from alkyl halides, benzene or chlorobenzenesulfonic acid esters from alkanols and methyl and ethyl sulfates, and A is in particular Cl- or CH₃CH₂OSO₂-;
  R⁵ is H, alkyl, hydroxyalkyl, aralkyl or - (CH₂) _n -COO-C₁-C₁₈-alkyl with n equal to 1 to 5, where R⁵ is preferably methyl, ethyl, propyl, butyl or benzyl;
  G means the groups
  - (CH₂) _n -COO⁻ with n equal to 1 to 5, - (CH₂) ₃SO₃⁻,
  
• 2. Cyclic amino groups of the formulas
  
  where Y is a divalent radical of the formulas
  - (CH₂) ₄-, - (CH₂) ₅-, - (CH₂) ₂-O- (CH₂) ₂- and - (CH₂) - (CH₂ where R², R⁵, A⁻ and G⁻ are as previously defined , and
  R⁷ and R⁸ are independently H, C₁-C₆-alkyl or C₁-C₆-hydroxyalkyl, with the proviso that R X is not H when X is oxygen;
• 3. Aromatic amino groups of the formulas
  
  and
• 4. Condensed aromatic groups of the formulas
  
  and
• 5. a heterocyclic amino group of the formulas
  - (R²) _k -E (5a), - (R²) _k -E⁺-R⁵A⁻ (5b) and - (R²) _k -E⁺-G⁻ (5c),
  wherein Z is halogen or methyl, a and b are a number from 0-3, k represents 0 or 1, and E is pyrrole, pyrazole, imidazole, triazole, indole or imidazole with hydroxyalkyl or alkyl, or for with aminoalkyl- or hydroxyalkyl substituted pyridazine, pyrimidine, pyrazine or quinoxaline.

Examples of fluorine-containing amphoteric surfactants are:
N- [3- (dimethylamino) propyl] -2- (3) - (1,1,2,2-tetrahydroperfluoroalkylthio) succinic acid monoamide,
N-methyl-N- (2'-N, N-dimethylaminoethyl) -2- (3) - (1,1,2,2-tetrahydroperfluoroalkylthio) succinic acid monoamide,
N- (2-dimethylaminoethyl) -2- (3) - (1,1,2,2′-tetrahydroperfluoroalkylthio) succinic acid,
2 (3) - (1,1,2,2-tetrahydroperfluorodecylthio) succinic acid mono- [2-N, N-dimethyl) aminoethyl] ester,
2- (3) - (1,1,2,2-tetrahydroperfluorodecylthio) succinic acid mono (2′-quinolino-ethyl) ester,
N, N′-bis [(n-propyl-3) - (1,1,2,2-tetrahydroperfluorooctylthio) succinic acid monoamido] piperazines,
N- [3- (dimethylamino) propyl] -2- (3) - (heptafluoroisopropoxy-1,1,2,2-tetrahydroperfluoroalkylthio) succinic acid monoamide,
2- (1,1,2,2-tetrahydroperfluorooctylthio) N- [3- (dimethylamine) propyl] -2-methyl-succinic acid monoamide,
N-ethyl-N- (2′-N ′, N′-dimethylaminoethyl) -2- (3) - (1,1,2,2-tetrahydroperfluoroalkylthio) succinic acid monoamide,
N- [3- (dimethylamino) propyl] -2- (3) - (1,1,2,2-tetrahydroperfluorooctylthio) succinic acid monoamide,
N-methyl-N- (2'-N'-dimethylaminopropyl) -2, (3) - (1,1,2,2-tetrahydroperfluorooctylthio) succinic acid monoamide,
N- [3- (dimethylamino) propyl] -2- (3) - (1,1,2,2-tetrahydroperfluorodecylthio) succinic acid monoamide,
N- [3- (dimethylamino) propyl] -2- (3) - (1,1,2,2-tetrahydroperfluorododecylthio) succinic acid monoamide,
Reaction product of
N- [3- (dimethylamino) propyl] -] - 2- (3) - (1,1,2,2-tetrahydroperfluorodecylthio) succinic acid monoamide and propane sultone,
Reaction product of
N- [3- (dimethylamino) propyl] -2- (3) - (1,1,2,2-tetrahydroperfluorooctylthio) succinic acid monoamide and chloroacetic acid, or zonyl FSB (DuPont).

The emulsions according to the invention are distinguished by their stability against phase separations even in turbulent flow conditions up to temperatures of at least about 50 ° C., and at the same time by the ease of phase separation in crude oil and water at temperatures above 50 ° C., preferably 50 to 75 ° C. . The ease of phase separation at elevated temperatures is unexpected and surprising and offers great Advantages. For example, it is unnecessary to add a de-emulsifier, and the separated aqueous phase can therefore be easily reused if desired.

Another object of the invention is a process for transporting crude oil, in which the crude oil is converted into a low-viscosity emulsion of water and crude oil by using an aqueous solution containing the amount of soluble fluorine-containing surfactant and optionally a hydrocarbon surfactant according to the invention under turbulent conditions Conditions mixed with water, and the crude oil transported in the form of the emulsion formed. If the surface tension is sufficiently low, e.g. below 2, then the emulsion can be formed spontaneously.

After transporting the emulsion through a pipeline to the destination, the emulsion is separated into the two phases by heating above 50 ° C. and the crude oil is isolated for further processing.

The following test methods and examples illustrate the invention. Parts are parts by weight unless otherwise stated.

Description of the laboratory method 1 Control:

The crude oil is placed in a closed container. The container is heated in a forced air oven at 50 ° C for 15 minutes. The container is then opened and the oil is stirred at high stirring speed (Polytron® mixer) for one minute in order to obtain a homogeneous oil. The viscosity measurements are carried out with a 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 for 5 minutes at 20 rpm. The temperature is measured and the viscosity is determined at 20 and 10 rpm.

The above procedure is repeated with the addition of surfactants and water to form an emulsion. An oil-soluble surfactant is added to the oil in the container. Then water containing a certain amount of a water-soluble surfactant is added to the oil. The thermal treatment and viscosity measurement are carried out as indicated above.

Description of the laboratory method 2

A viscometer (Fann 35A / SR12), which is equipped with an end-sealed stirring test beaker, a hollow pendulum weight, a double-walled rotating test beaker with a circulating heat bath, is used for the viscosity measurements. 22.5 g of crude oil are added directly to the stirring test beaker and 250 ppm of an oil-soluble surfactant are added, followed by 7.5 g of water containing 0.1% water-soluble surfactant. The stirred test beaker is weighed with its contents, heated for 15 minutes in a forced-air oven at 50 ° C. and then weighed again to avoid any weight loss. The test beaker is attached to the viscometer and lowered into the double-walled rotary test beaker, which contains water as a heating medium. The temperature is controlled by a circulating heat bath connected to the top of the double-walled, rotatable test beaker. The mixture of oil and water is stirred for mixing and for equilibrium at 25 ° C. for 5 minutes at 300 rpm. The viscosity is determined at 300, 200 and 100 rpm at 25 ° C. Then the emulsion is sheared at 600 rpm (shear rate = 1021 sec⁻¹) for five minutes and the viscosity is measured again. The viscosity measurements are repeated at a higher temperature.

Example 1-6:

The examples demonstrate the lowering of the viscosity of crude oil, which is achieved by adding a surfactant mixture with one or more fluorine-containing compounds to an oil / water mixture. A sample of Canadian crude oil and a mixture of Canadian crude oil (3 parts), 250 ppm compound A and water (1 part) containing 250 ppm compound B are prepared and the viscosities are determined according to laboratory test method 1. The results are shown in Table I.

Examples 7 and 8:

The viscosity of crude oil from Venezuela, which contains 15% water, is measured. The crude oil is mixed with 500 ppm of compound C and 500 ppm of compound D and the viscosity is measured again. The results are shown in Table II.

Example 9:

Two mixtures of crude oil and water are produced according to laboratory test method 2. One sample contains Canadian crude oil (3 parts), water (1 part) and 250 ppm each of Triton X-100®¹ and compound B from Example 1, the other 100 each ppm Triton X-100® and compound B from Example 1. The viscosity measurements are carried out as before, but without scissors. A sharp drop in viscosity indicates the phase separation of the emulsion. The results are summarized in Table III.

Example 10:

The example illustrates the stability of an emulsion of oil and water, which contains a fluorine-containing surfactant, after strong shearing. A mixture of Canadian crude oil (3 parts) containing 250 ppm Triton X-100 and 1 part water containing 250 ppm Compound B from Example 1 is prepared. The viscosity is measured according to laboratory test method 2 before and after shearing (shear rate = 1021 sec⁻¹). The correspondence between the viscosities of the starting emulsion and the sheared emulsion at any temperature indicates the stability of the emulsion. The results are summarized in Table IV.

Claims (10)

1. Emulsion of crude oil and water, which contains 0.001 to 1 wt .-%, based on the weight of the emulsion, of a soluble fluorine-containing surfactant of the formula I.
(R _f ) _n A _m Q (I),
wherein
R _{f represents} an inert, stable, oleophobic and hydrophobic fluoroaliphatic group with up to 20 C atoms,
n is a number from 1 to 3,
A represents a direct bond or an organic bridging group which is covalently bonded to R _f and Q,
Q represents an anionic, nonionic or amphoteric group and m is a number from 1 to 3,
wherein the emulsion contains 0 to 2% by weight of an emulsion-promoting hydrocarbon surfactant and at least 0.005% by weight of fluorine-containing surfactant and hydrocarbon surfactant are present, and the emulsion contains 15 to 90% by weight of water, based on the emulsion, so that the viscosity the emulsion is less than 50% of the viscosity of the crude oil. 2. Emulsion according to claim 1, wherein the water content is between 20 to 70 wt .-%, based on the weight of the emulsion. 3. Emulsion according to claim 1, wherein R _f in formula I represents linear C₄-C₁₈ perfluoroalkyl or mixtures of such radicals. 4. Emulsion according to claim 1, wherein n and m in formula I each represent 1. 5. Emulsion according to claim 1, wherein the fluorine-containing surfactant is anionic or nonionic. 6. An emulsion according to claim 1, wherein the hydrocarbon surfactant is contained in an amount of 0.001% by weight. 7. Emulsion according to claim 1, wherein the hydrocarbon surfactant corresponds to formula II,
(R) _n A _m Q (II),
wherein R is an aliphatic hydrocarbon group with 6 to 24 C atoms, an aryl group with 6 to 14 C atoms or an alkaryl group with 7 to 24 C atoms
A is a direct bond or an organic bridging group that is covalently bonded to R and Q,
Q is an anionic, nonionic or amphoteric group,
n is a number from 1 to 3 and
m is a number from 1 to 3. 8. Emulsion according to claim 1, which at a temperature between 55 and 75 ° C have a spontaneous separation into an aqueous phase and a crude oil phase. 9. A method for transporting viscous crude oil by converting the crude oil into an aqueous emulsion according to claim 1 with the addition of water, a fluorine-containing surfactant of the formula I and optionally a hydrocarbon surfactant under turbulent conditions, transporting the oil in the form of the emulsion formed and recovering the crude oil by phase separation by heating the emulsion to above 50 ° C. 10. The method according to claim 9, wherein the phase separation of the emulsion is carried out by heating it between 55 and 75 ° C.