NO149557B - PROCEDURE FOR OIL EXTRACTION FROM UNDERGROUND OIL SOURCES AND SURFACTIVE AGENTS FOR USE IN EXECUTION OF THE PROCEDURE - Google Patents

Description

When extracting oil from oil-bearing sources is

it is usually possible to extract only a small part of the liquefiable oil on site by the so-called primary extraction methods which only utilize the natural pressure that is available

present in the source. In order to increase recovery above what is economically

misc is extracted using such natural forces, several extraction techniques have been developed. One of the most commonly used advanced extraction techniques involves the use of waterflooding. The water is usually injected into the wedge-

it to push crude oil towards the production site. The amount of oil recovered by waterflooding depends on such factors-

is like the interfacial tension between water and crude oil, the rela-

tive velocities of crude oil and water and moisture characteristics of the rocks that hold the oil in the source.

To increase the efficiency of waterflooding tech-

when surfactants are added to the water. The surfactant lowers the surface tension of the water

dige liquid and the interfacial tension between the aqueous liquid and petroleum and increases the water-wetting properties thereof, thereby reducing the capillary forces in the underground formations to be treated. This helps to release the oil from underground sand and rock formations. Generally, aqueous compositions containing petroleum sulphonates have been used, advantageously in combination with controlled amounts of

there of NaCl. Also, sodium carbonate and/or sodium tripolyphosphate can be added to such compositions as an additive to protect petroleum sulfonate surfactant from loss due to precipitation reactions with divalent cations. Furthermore, the use of thickeners has been proposed to increase the sliding effect of waterflooding. A waterflooding technique involves using a preflushed or conditioned sludge to reduce the amount of divalent cations (eg, Ca 2 + , Mg 7 + ) that would precipitate or absorb the surfactant, a surfactant containing sludge to

loosen and squeeze out the oil from sand and rock, and a speed-buffer mud that can be used to resist the surface ac-

tive system. Preflush or the conditioning mud is free

for cations that would affect the surface activity and may contain complete or partial solutions of sodium carbonate and sodium tripolyphosphate and the like. Optionally, NaCl brine can then be injected to optimize the salt concentration for optimal extrudability. The sodium ions therefore replace calcium and magnesium ions. Strong acid can be used to break up carbonate rock formations. After injection with the aqueous surfactant solution, the rate buffer sludge is injected. The rate buffer usually contains a water-soluble polymer such as polyacrylamide or a biopolymer (eg natural rubber).

After the injection of the velocity buffer or the control mud, a driving fluid is injected to replace the previously injected fluids through the sand or rock formation. The nature of the drive fluid is not critical and can for example be locally available water. However, the driving fluid should not be incompatible with the underground formation. In an embodiment of the above technique, where a preflush sludge, surfactant sludge and velocity buffer sludge are used,

is the surfactant sludge in the form of an aqueous microemulsion of oil in combination with petroleum sulphonates, co-surfactants such as alcohols and electrolytes.

According to the invention, there is provided a method for treating underground formations to stimulate the flow of oil therefrom and surfactants for use in such treatment.

The invention relates to a method for extracting oil from underground oil sources by injecting an aqueous surface-active agent to release oil from the source, the method being characterized by the use of an agent containing a surface-active compound with the formula

where R, is a hydrophobic-oleophobic fluoroaliphatic group with 4-24 carbon atoms, Z means a divalent connecting group,

A is a divalent hydrophilic organic radical, Q is a divalent connecting group, is a hydrophobic-oleophilic aliphatic radical with 6-24 carbon atoms or araliphatic radical with at least 9 carbon atoms, and m and n are independently 0 or 1, the fluorine-containing surfactant compound has a solubility in water at 30°C of at least 0.01% by weight, exerts a surface tension of less than 30 dyne/cm at 0.1% by weight active compound in deionized water and exerts an interfacial tension of less than 12 dyn/cm at 0.1% by weight active compounds in deionized water, measured in relation to cyclohexane and optionally additionally contains non-fluorinated anionic, mixtures of anionic and nonionic or cationic surfactant compounds.

Optionally, the aqueous surfactant contains further surfactants, e.g. of non-fluorinated type, which are anionic, mixtures of anionic and nonionic or cationic. The solubility of desirable surfactants in deionized water may be less than the concentration used (0.1% by weight in deionized water) when measuring surface and interfacial tensions. In such cases, the measurements are carried out in a saturated heterogeneous aqueous system containing 0.1% of the fluoroaliphatic surfactant in deionized water.

Preferably, the fluoroaliphatic surfactant exerts a surface tension of 0.1% active in deionized water of approx. 16-28 dyne/cm and an interfacial tension of less than 12 dyne/cm, e.g. of approx. 4-10 dyne/cm in deionized water measured against cyclohexane.

The fluoroaliphatic surfactants usually contain at least 2-50% by weight fluorine and preferably 5-35% by weight fluorine.

R^-radical is preferably a straight or branched perfluoroaliphatic radical which contains 4-24 carbon atoms and may be interrupted by oxygen.

In a preferred embodiment, the Rf group is linear or branched perfluoroalkyl with 4-20 carbon atoms, linear or branched perfluoroalkenyl with 4-20 carbon atoms, or linear or branched perfluoroalkyl-polyfluoroalkyl-perfluoroalkylene with up to 24 carbon atoms.

Suitable R^ groups are those with the following formula:

wherein n is 4 - 20 wherein n is 4 - 20 and -<1> wherein m is 1-3, p is 2-4, q is 0-6 and r is 1-10, with the precaution atm+p+q +rer at least 4. Suitable Rf groups with formula (2) are CF^ICF,,)^ where x means 3 - 19 and mixtures thereof, as well as those of the type

and mixtures thereof.

Suitable R^ groups with formula (3) are those of the type CF3(CF2)Q_g-CF=CF(CF2)1-9 and mixtures thereof, as well as branched analogues such as

Representative R^ groups of formula (4) are those of the type and mixtures thereof.

Rj radicals can also contain substituents besides fluorine, such as chlorine and hydrogen. However, no more than 20% of such substituents should be different from fluorine for the radical to exert its hydrophobic-olephobic character.

Suitable R₂ radicals containing such other substituents include the following:

where a is 0 to 8, and b is 0 to 8, provided that (a+b) is between 2 and 16.

The nature of the divalent linking group Z, when present, is not critical as long as it performs the essential function of covalently linking the fluoroaliphatic group, R^, to the hydrophilic organic radical A.

Thus, Z can, for example, be selected from among the following:

~C1~C6 alkylene-'

-phenylene-,

-(C 1 -C 8 -alkylene)- R^(C 1 -C 8 -alkylene)-,

- (C-j^-Cg-alkylene) ) ,

- R^-- (C^-Cg-alkylene)-,

~R1~(Ci~c6~alkylene-Ri)

~<R>l"'

-R1~phenylene-(C^-Cg-alkylene-R^)-,

-R^-phenylene-, or

-phenylene-R|

wherein in each case said alkylene and phenylene are independently unsubstituted or substituted by hydroxy, halogen, nitro, carboxy, C-L-Cg-alkoxy, C-|_-Cg-alkanoyl, C^-Cg-carbalkoxy, G-^-Cg- alkanoyloxy or C 1 -C 8 -alkanoylamino. The alkylene radical can be straight-

lined or branched.

R-^ and R^ mean independent

, -NR2CO-, -CONR2-

R 2 means hydrogen, C 1 -C 8 -alkyl or C 1 -C 8 -alkyl, substituted with: C 1 -C 8 -alkyloxy, halogen, hydroxy, carboxy, C 1 -C 8 -carbaloxy, C 1 -C 8 -alkanoyloxy or C 1 -C 8 -alkanoylamino.

In addition, Z may contain a cycloaliphatic or heterocyclic radical.

Thus, R-^ can, for example, additionally mean

where R, means -ORo, -OM where M is defined below, or -NHR-;

R

R. means -0- or |2

-N- , and

R 5 means hydrogen, halogen, C 1 -C 8 alkyl or C 1 -C 8 alkoxy, or R 5 means:

Suitable hydrophilic radicals A are, for example, the hydrophilic divalent radical with the following formula:

wherein R 8 means hydrogen, or a mixture of hydrogen and methyl, with the proviso that such R 8 is predominantly hydrogen; where R 7 means hydrogen, lower alkyl or hydroxyethyl; wherein Ry is hydrogen or hydroxyethyl; where t means 1 to 3 and Rg means lower alkyl, hydroxy-lower alkyl or iCH2CH2O)gH; wherein t is 1 to 3 and T is -SO 3 M, -COOM, -PO 3 M, -OSO 3 M or -OPO 3 M 2 , and M is hydrogen, ammonium or an alkali metal cation; or

wherein Rg, R^q and R^ are independently hydrogen; C 1 -C 4 -alkyl or C 2 -C 4 -alkyl substituted with hydroxy, C 1 -C 4 -alkyloxy or hydroxy-C 2 -C 4 -alkyl; and one of Rg and R1Q can additionally be benzyl; u means 0 or 1;

R 1 additionally means C 1 -C 8 alkylene substituted by sulfo or carboxy; X means acetate, halogen, methosulphate or hydroxyl anion where u means 1 and R^ is different from said C-j^-Cg alkylene, and t means 1 to 3.

In each of the above formulas where mentioned, s means 2 to 60, preferably 5 to 25.

Mixtures of the above hydrophilic radicals can

be present.

Also suitable are hydrophilic divalent radicals in which at least part of the hydrophilic character is due to a dependent group such as a divalent radical of formula:

where n-^ and n independently mean 0 to 2 0 and n 2 and n^ independently mean 1 to 2 0; wherein n5 means independently 2 to 20 and n^ independently 1 to 10, or

where R14 means hydrogen, C1~C4 alkyl, or (OCH2CH2)n OH;

^9 ^ 2 independently denotes 0 to 4, y 3 denotes 1 to 8, and n2 and n4 independently denote 1 to 20.

Q is a divalent connecting group and, in the same way as Z, is not critical as long as it performs the essential function of covalently binding the hydrophilic organic radical A to the hydrophobic-oleophilic group RHC-

Thus the connecting group Q is independently selected from the groups indicated for Z, with the proviso that when R^ or Rj is directly bound to A, and A ends in an oxy or amino ligand, and Ri in this position is different from:

, -s-, , -oso2-, -oso3~,

or -0-.

R 1 is a hydrophobic-oleophilic, aliphatic or araliphatic monovalent group.

Suitable R^ groups include hydrophilic-oleophilic higher alkyl or alkenyl or 6-24 carbon atoms, which are unsubstituted or substituted with: chlorine, bromine, alkoxy of up to 18 carbon atoms, nitro, alkanoyl of up to 18 carbon atoms, alkylmercapto of up to 18 carbon atoms, amino, C 1 -C 8 -alkylamino or di-C 1 -C 8 -alkylamino.

Said alkyl or alkenyl is preferably with at least 8 carbon atoms. The alkyl and<:>alkenyl groups may be straight or branched. Mixtures of these can be used.

In addition, the R^ group can be a group, with formula:

wherein R 5 means C 1 -C 6 alkyl, n? means 5-20, and Rg means hydrogen or alkyl of up to 24 carbon atoms.

Furthermore, the R 1 group can be a hydrophobic-oleophilic araliphatic radical with at least 9 carbon atoms.

Suitable such groups include those of formula:

wherein ng means 0 to 1;

R-^cj means alkyl of up to 20 carbon atoms, alkoxy of up to 20 carbon atoms, alkanoyl of up to 20 carbon atoms, mono- or dialkylamino of up to 20 carbon atoms, alkylmercapto of up to 20 carbon atoms, alkanoyloxy of up to 20 carbon atoms, or caralkyloxy of up to 20 carbon atoms;

R-^g means hydrogen, halogen, nitro or R-^-

Also suitable are hydrophobic-oleophilic groups with the formula:

where ng, R^^ and R-^ have the above meaning.

In addition, the group ~Qn-R|jc in which n means 1 can mean a group of formula

wherein R^-j and R^g independently of each other mean higher alkyl groups

with 6 to 24 carbon atoms, or the group —K^2~cg_alkylene^—°"

wherein R^g and Rjq are higher alkyl of 6 to 24 carbon atoms.

Preferred compounds are those which are substantially non-ionic, i.e. free of strongly acidic groups, such as -SO^H and -PO-^H and free of strongly basic quaternary ammonium groups.

Among such preferred substantially non-ionic surfactants, particularly luminous are those which both exert a surface tension at 0.1% activity in deionized water and approx. 16 to 28 dynes/cm, provides a solubility in water of at least 0.01% by weight, exerts an interfacial tension of less than 12 dynes/cm at 0.1% by weight active in deionized water measured against cyclohexane and wherein the corresponding hydrocarbon surfactant R ^-Q^-A-OH, has an apparent HLB (hydrophilic-lipophilic balance) in the range of approx.

5 to 24, and preferably in the area from 12 to 18.

The HLB of a substantially nonionic hydrocarbon surfactant is a well-known indication of the percentage weight of the hydrophilic portion of the nonionic hydrocarbon surfactant molecule. For example, Ind. and Eng. Chem, Anal. Ed. Vol. 18, page 500(1946).

A particularly preferred class of fluorochemical surfactants are those of the formula:

where R^ straight or branched means perfluoroalkyl with 4 to 20 especially 4 to 12 carbon atoms, R^ means alkyl with 6 to 24, preferably 12 to 18 carbon atoms or where R- 21 means alkyl with 3 to 20, preferably 6 to 12 carbon atoms and R22 means hydrogen, halogen (chloro, bromine, fluorine), nitro or R2^» m means 0 or 1, s means 5 to 30, Z means -COO-, -SO3-, -O-, -C1-C4 -alkylene-COO-, -C^-C^-alkylene-SC^,

Preferred are the compounds with formula (5), where Rf °^ s ^ar ^e given meanings and m and n mean zero.

Preferred are also the compounds with formula (5),

wherein Z means -C-C-C-Alkylene-S

as by formula: or where Z means by formula:

wherein Rf, RHC and s have the above meaning.

The fluorochemical surfactants used according to the invention can be produced according to known methods. Thus, e.g. the fluorochemical surfactants are produced by reacting known hydrocarbon surfactants with the formula:

with a fluoroaliphatic acid halide in an inert solvent.

For example, <CF>3(CF2)7SO2F prepared according to US patent no. 2,759,019 can be reacted with H(OCH2CH2)5_2QN(stearyl)2 in diethyl ether as solvent and pyridine or triethylamine as acid acceptor to give the corresponding ester with formula:

Analogously, n-C3F7OCF(CF3)COF as stated in Canadian Patent No. 725,740 can be reacted with octylphenoxy-poly(ethyleneoxy)ethanol having an average molecular weight between 514 and 778 in the presence of diethyl ether and pyridine as acid acceptor to give the corresponding ester.

Alternatively, the α-perfluoroalkene of formula C n F2„ n—l, where n means 6-2 0, can be reacted with a hydrocarbon surfactant of formula: R„0-Q n-A-OH in the presence of potassium carbonate in an inert solvent, such as methyl -ethyl ketone or acetone at a temperature of 20-70°C,

to give the corresponding fluoroaliphatic ether.

For example, an oleic acid ethylene oxide condensate (molecular weight of about 680) can be reacted with tetrafluoroethylene pentamer in the presence of potassium carbonate in acetone to give a product of the formula C10F19°(CH2CH2°)10<C>OC15H29" If used a mixture of cetyl/oleyl ethylene oxide condensate (molecular weight of approx. 550) gives a corresponding cetyl/oleyl ether product with the formula

C10F19° (CH2CH20) 10C16H31/33 .•

Such compounds and their preparation are discussed in British patent 1,371,054.

Alternatively, fluoroaliphatic isocyanates and carbamic acid halides can be reacted with hydrocarbon surfactants of the formula R„ n- Q -A-OH or R_„ -Q -A-NHR- to give the corresponding urethanes and urea, resp. The reactions are preferably carried out in the presence of an inert medium at temperatures of 20 to 50°C. Where the fluoroaliphatic carbamic acid halide is a reaction participant, it is preferably added to a tertiary amine such as triethylamine or pyridine to accelerate the reaction and remove the hydrogen halide formed.

For example, 1,1-dihydroperfluorooctylcarbamyl chloride, with formula C7<F>15CH2NHC0C1, prepared according to German patent 1,145,606, is added slowly to ethoxylated (15 mol) coconut fatty acid in diethyl ether, in the presence of triethylamine as an HCl scavenger, while stirring. The resulting product has the formula

<C>7<F>15CH2NHCOO—*CH2CH2~°i5' C0<R>HC' where RHC is the coconut fatty acid hydrocarbon residue.

In a similar way, CF3(CF2)gNCO can be prepared in accordance with US patent no. 2,617,817, is reacted with stearin or lauric acid-amide-ethyleneimine (4 to 6 mol) condensate, such as those described for example in US Patent No. 2,163,807 in an inert diluent to form a product of formula CF-. (CF-,) ,NHCO (NHCH0CH„) . ,

J £■ o Z 2. 4 —D —NHCO-RHC, wherein RHC is the hydrocarbon residue of stearic or lauric acid.

The product can be neutralized with aqueous HCl or H2S04 to form the corresponding salts, or can be alkylated with dimethyl sulphate or methyl halide, such as methyl bromide to form the tertiary or quaternary ammonium derivatives thereof. Alternatively the curry product

reacted with ethylene oxide, e.g. in quantities of 4 to 15 mol per

moles of product to form the ethoxylated derivatives thereof in the presence of an HCl catalyst.

Analogously, phosgene can be reacted with nonionic hydrocarbon surfactants of formula R^-Q^-A-OH to form the corresponding chloroformate and the acid chloride reacted with a fluoroaliphatic alcohol or amine to form the corresponding carbonate or urethane, resp. Preferably, the reaction is carried out in the presence of a tertiary amine, such as triethylamine, and an inert diluent.

For example, C12H25S (CH^t^O-)-^-^ can be reacted with phosgene in the presence of triethylamine to give the corresponding acid chloride C12<H>25<S>(CH2CH20^ioCOC1' SOm p^ is in turn reacted with a fluoroaliphatic alcohol such as (CF3)2CFO-CF2CF2-CH2CH2CONH(CH2)30H, disclosed in US Patent No. 3,697,564 in the presence of triethylamine in diethyl ether for

to give a product with formula

(CF3)2CFO-CF2CF2CH2CH2CONH(CH2)3OCO(OCH2CH2-) s-ci2H25'

Similarly, C^gF^gOCgH^SC^Cl as disclosed in British Patents 1,130,822 and 1,270,662 can be reacted with polyoxyethylene (20)sorbitan monolaurate in the presence of triethylamine in an inert diluent to form the corresponding ester.

Preferably, fluorochemical surfactants can be prepared by reacting a hydrocarbon surfactant of the formula Ruo-Q -A-OH with an equimolar amount of toluene diisocyanate to form a 1:1 urethane adduct thereof, and reacting the urethane monoisocyanate with polyfluoro aliphatic amine or alcohol.

Thus, nonylphenoxypolyethoxyethanol with an average of 4 moles of ethylene oxide can be reacted with one mole of toluene diisocyanate to form the corresponding 1:1 adduct, which in turn is reacted with a perfluoroalkylalkylamine of formula CgF^7(CH2)^NH2 which can be prepared in accordance with US -patent 3,257,407 to form the corresponding urea derivative.

Analogously, many fluorochemical surface-active compounds of the formula R^-Z -A-OH can be reacted with suitable aliphatic

in

or araliphatic acid halides, isocyanates and the like, to form suitable fluorochemical surfactants for use according to the invention.

For example, CgF17S02N(C2H5)-CH2CH2(OCH2CH2)1Q-0H

discussed in US patent 2,915,554 is reacted with dodecylbenzenesulfonyl-

chloride in diethyl ether in the presence of triethylamine to give the corresponding sulfonate ester.

Useful surfactants for use according to the invention can also be prepared by reacting a fluoroaliphatic thiol with an ethylenically unsaturated dicarboxylic acid anhydride and reacting the resulting anhydride condensate with a. equimolar amount of hydrocarbon surfactant of formula R„_-Q -A-OH or R„~-Q -A-NH- to form the resulting half-time n nu n z

ester or half amide, respectively. Alternatively, the ethylenically unsaturated dicarboxylic acid anhydride can be reacted with an equimolar amount of hydrocarbon surfactant of formula R^-Q -A-OH or , Rjj^-Q -A-NH2, for example, and the reaction product is reacted with a fluoroaliphatic thiol.

For example, dodecylphenoxypolyethoxyethanol (containing 9 moles of ethylene oxide) can be reacted with an equimolar amount of maleic anhydride in an inert diluent such as sulfolane to give the corresponding half-ester with formula:

The half ester can be reacted with a fluoroaliphatic thiol such as C9F19<C>2<H>4<S>H, prepared according to US Patent Nos. 3,172,910 and 3,088,849. The reaction is preferably carried out in substantially stoichiometric amounts in aqueous ethanol in the presence of minor amounts of sodium hydroxide and a tertiary amine, such as piperidine, at from 20 to 75°C, e.g. to form a product of formula: prepared according to US Patent No. 3,471,518 is reacted with the compound of formula:

disclosed in US Patent No. 2,341,84 6 by refluxing equimolar amounts in dioxane to form the corresponding half ester.

Likewise, the compound with formula:

where R^ is a mixture of C5~c^0 Per^fluoroalkyl, prepared by reacting norbornene anhydride and R^ CB^CB^SH in the presence of a small amount of azobutyronitrile as a catalyst, reacted with 3-(n-dodecyl-amino )-propylamine in equimolar amounts at a temperature of 20 to 50°C in an inert diluent such as toluene and dehydration of the product by azeotropic distillation of water to give the corresponding imine which can again be ethoxylated with 10 moles of ethylene oxide in an aqueous acid medium to give a product of formula: 0

Some of the fluorochemical surfactants which can be used according to the invention are known compounds.

Suitable fluorochemical surfactants as indicated above and used according to the invention can be easily prepared from known starting materials by ordinary techniques, such as those indicated above and which are further shown in the following examples.

Preferably, the fluorochemical surfactants are used alone in an aqueous system or in combination with a common water-flooding surfactant. Such surfactants for enhanced oil recovery are well known and include anionic surfactants such as petroleum sulfonates, synthetic alkyl-aryl sulfonates and similar anionic-nonionic surfactant systems, such as those disclosed in US Patent No. 3,811,504, 3,792,731 and 4,005,749 and cationic surfactant systems.

Mixtures of cationic and anionic surfactants should generally be avoided as they may be incompatible due to interaction.

The total amount of surfactant based on aqueous medium can vary within wide limits, e.g. between 0.01 and 40% by weight, usually 0.05 to 20% by weight. When a mixture of fluorochemical surfactant according to the invention and a conventional: waterflooding surfactant is used, there is usually present at least 1%, preferably at least 4% of the fluorochemical surfactant, based on the amount of non-fluorochemical surfactant.

The aqueous surfactant liquid may also preferably contain suitable co-surfactants such as aliphatic or alkyl-aryl alcohols with a molecular weight of 40 to 220 in amounts up to 10% by volume of the solution. A monovalent salt can also be present in the aqueous medium in amounts up to . 5% by weight based on the aqueous medium for salinity control.

Various thickeners such as guar gum or polysaccharides and sacrificial substances such as inorganic polyphosphates or alkali metal carbonates may also be present.

In one embodiment, surfactant liquids may be in the form of an aqueous petroleum oil emulsion containing 0.5 to 40% by weight of oil based on the weight of the aqueous phase.

In a further embodiment of the invention, the final portion of the aqueous surfactant liquid, or aqueous petroleum oil emulsion comprises a lower concentration of non-aqueous ingredients than the initial portion injected into the source, from which the oil is recovered. Use of such a concentration gradient thus reduces the total amount of emergency

surfactant in the oil extraction procedure.

The invention shall be explained in more detail by means of some non-limiting examples, where all parts are parts by weight if nothing else is indicated.

Example 1

In a 500 ml flask equipped with a thermometer, piping and nitrogen inlet, 84.2 g (0.075 mol) of polyethoxylated cetyl alcohol with an average of 20 ethoxy units and with formula: is stirred at 50-55°C under nitrogen. Boron trifluoride in the form of the diethyl ether complex (47.3% BF^) was added in amounts of 0.4 g. Then 6.1 g of epichlorohydrin (0.066 mol) was slowly added to the mixture while maintaining the temperature at 5 0- 6 0°C over a period of approx. 10 minutes. The reaction mixture was then stirred at a temperature of 50-60°C for a further 30 minutes. The product formed has the formula:

140.3 g of anhydrous isopropyl alcohol and 27.9 g of RfCH2CH2SH were then added to this reaction product, where Rf is linear perfluoroalkyl with the following R^ distribution: 0.9% C4Fg-, 32.9% C6F13-, 37.5% CgF ^-, 22, 99% C-^F^-, and 5.3% ci2<F>25 (<g>average molecular weight approximately 465) and the mixture is stirred at approx. 50°C. Then 5.4 g of 50% aqueous NaOH (0.0672 mol) are added slowly at such a rate that maintains the reaction mixture at 50-60°C. A white precipitate of NaCl is formed. The mixture was stirred for an additional hour at 50-55°C and changed from colorless to slightly yellow. The solution was then filtered to remove the by-product NaCl. By drying, 73.6 g of the product was obtained (approx. 70% yield). The product has the formula:

Example 2

As the method according to Ex. 1 was polyethoxylated stearyl amine of formula

(where q + r is 15)

in an amount of 54.69 g (0.063 mol) reacted with 5.09 g (0.055 mol) of epichlorohydrin in the presence of 0.3 g of BF^; diethyl ether complex and the resulting reaction product reacted with 23.25 g of R^Cf^CI^SH according to Ex. 1 in the presence of 4.48 g of 50% aqueous NaOH in 98.85 g of isopropanol. The reaction product was stirred for 2 hours before filtration to give 151.47 g of amber cloudy solution. By refiltration, 142.01 g of clear amber colored solution was obtained. Upon drying, 46.43 g of the product with formula was obtained:

Example 3

Using the method according to Ex. 1 was 264.0 g of ethoxylated (15) p-nonyl-phenol with formula

reacted with 24.42 g of epichlorohydrin in the presence of 1.6 g of BF^; The diethyl ether complex and the product thereof were then reacted with 111.6 g of R^CI^CI^SH, in which Rf has the distribution as in Ex. 1, in the presence of

21.50 g of 50% aqueous sodium hydroxide and 460.4 g of isopropyl alcohol.

The resulting reaction product has the formula:

Example 4

Maleic anhydride, 2.55 g and 2.55 g of sulfolane as solvent were added to 36.45 g of dinonyl-polyethoxylated (24) phenol of the formula: and stirred for 20 hours at -60°C to form a reaction mixture containing a half esters with formula:

To this reaction mixture was then added 0.1 g of triethylamine and 11.63 g of RfCJ^CH^SH with the R^ distribution according to Ex. 1 under nitrogen and the mixture stirred at 60°C for approx.

7 hours. The product has the formula:

Example 5

To measure the effectiveness of fluorochemical surfactant in expelled oil from an oil-bearing underground formation by increasing the effectiveness of the aqueous medium, the following screen technique was used: E£2§§^Y£§: 20 g of sand-oil- mixture (10% A.S.T.M. oil No. 3 and 90% Ottawa standard sand 20-30 mesh) is placed in a 25 x 150 mm test tube. The sample solution (25 ml at 0.1% active of sample in deionized water) is carefully placed over the sand-oil mixture. The system is then left undisturbed for 18-20 hours. Any oil that percolates to the surface is removed with a pipette and weighed. The result is given as % recovered (ie the weight of the oil recovered

compared to the theoretical maximum of 2.0 g of oil in the tube).

3 to 5 trials are done for each sample for average value.

In the following tables, the compounds were charged

at 0.10% activity in deionized water, surface tension and interfacial tensions were measured against cyclohexane. Unless otherwise stated, the R^ distribution in the perfluoroalkyl surfactants was: 0.9% C4F9-, 32.9% C6F13-, 37.5% CgF^-, 22.9% C-^F^- and < 5.3%><C>12<F>25.

Example 6

In the following table, there are given formulations of different hydrocarbon surfactants with representative fluorochemical surfactants and their effectiveness in withdrawn oil according to the method indicated in Ex. 5. In the following table, hydrocarbon surfactant A is a commercial anionic sulfate surfactant. (Conco EL-30); hydrocarbon surfactant B is a polyethoxylated nonylphenol nonionic surfactant ("Igepal CO-710"), and surfactant C is petroleum sulfonate anionic surfactant ("Tetronate L").

The results of the above table show the benefits

which can be achieved by using formulations of conventional hydrocarbon surfactants together with fluorochemical surfactants in tertiary oil recovery.

Claims (10)

1. Method for oil extraction from underground oil sources by injecting an aqueous surface-active agent to release the oil from the source, characterized in that an agent containing a surface-active compound of formula is used where ^ is a hydrophobic-oleophobic fluoroaliphatic group with 4-24 carbon atoms, Z means a divalent connecting group, A is a divalent hydrophilic organic radical, Q is a divalent connecting group, R is a hydrophobic-oleoyl aliphatic radical with 6-24 carbon atoms or araliphatic radical with at least 9 carbon atoms, and m and n are independently 0 or 1, the fluorine-containing surfactant compound has a solubility in water at 30°C of at least 0.01% by weight, exerts a surface tension of less than 30 dyne/cm at 0.1% by weight active compounds in deionized water and exerts an interfacial tension of less than 12 dyne/cm at 0.1% by weight of active compounds in deionized water, measured in relation to cyclohexane, and possibly additionally contains non-fluorinated anionic, mixtures of anionic and nonionic or cationic surface-active compounds. 2. Method according to claim 1, characterized in that a fluorine-containing surface-active compound is used which exerts a surface tension of 16 28 dyne/cm at 0.1% by weight active compound deionized water and an interfacial tension of less than 12 dyne/cm at 0.1 wt% active compounds in deionized water, measured relative to cyclohexane. 3. Method according to claim 2, characterized in that a fluorine-containing surfactant is used. compound which is essentially non-ionic. 4. Method according to claim 3, characterized in that a surface-active compound is used - HO-A-Q -R^ which has a hydrophilic-lipophilic balance in the range 4 - 24. 5. Method according to claim 4, character i-, characterized in that a surface-active compound HO-A-Q-Rjj£ is used which has a hydrophilic-lipophilic equilibrium in the range 12 - 18. 6. Method according to claim 4, characterized in that a fluorine-containing surfactant compound with formula is used in which Rf means straight or branched perfluoroalkyl of 4-20 carbon atoms, R^ is alkyl of 6-24 carbon atoms or a group of formula in which R ^ means alkyl with 3 - 20 carbon atoms and R 22 means hydrogen, halogen, nitro or I^i' m ketyr 0 or 1, s means 5 - 25, Z means -COO-, -SO3~, -0-, - C 2 -C 2 -alkylene-COO-, COOH -C1-C4-alkylene-SO3 , -(^-C^-alkylene-S-C1H-CH^OO-<,> or -C1-C4-alkylene-S-CH2CHCH20-, n means 0 or 1 and Q means OH -CO or -S02~. 7. Method according to claim 6, characterized in that a surface-active compound is used where Rf is linear or branched perfluoroalkyl with 4-20 carbon atoms, Rur means alkyl with 6-24 carbon atoms or a group with the formula m and n mean 0 and s, R2^ and R22 when the meaning stated in claim 6. 8. Method according to claim 6, characterized in that a fluorine-containing surfactant compound with formula is used in which Rf, RHC and s have the meaning specified in claim 6. 9. Aqueous surfactant for oil extraction from underground oil sources, characterized in that it contains 0.01 - 40% by weight of a fluorine-containing surfactant with formula where Rf is a hydrophobic-oleophobic fluoroaliphatic group with 4-24 carbon atoms, Z means a divalent connecting group, A is a divalent hydrophilic organic radical, Q is a divalent connecting group, RHC is a hydrophobic-oleophilic aliphatic radical with 6-24 carbon atoms or araliphatic radical with at least 9 carbon atoms, and m and n are independently 0 or 1, the fluorine-containing surfactant for bond has a solubility in water at 30°C of at least 0.01% by weight, exerts a surface tension of less than 30 dynes/cm at 0.1% by weight of active compounds in deionized water and exerts an interfacial tension of less than 12 dynes /cm at 0.1% by weight active compounds in deionized water, measured in relation to cyclohexane and possibly a common water-flooding, non-fluorine-containing surfactant. 10. Surfactant according to claim 9, characterized in that it contains at least 1% by weight of the fluorine-containing surfactant, based on the weight of non-fluorine-containing surfactant.