WO2014063933A1

WO2014063933A1 - Process for mineral oil production using surfactants based on anionic alkyl alkoxylates which have been formed from glycidyl ethers

Info

Publication number: WO2014063933A1
Application number: PCT/EP2013/071285
Authority: WO
Inventors: Christian Bittner; Guenter Oetter; Jack Tinsley; Christian Spindler; Gabriela Alvarez Juergenson; Sophie Maitro-Vogel
Original assignee: Basf Se
Priority date: 2012-10-26
Filing date: 2013-10-11
Publication date: 2014-05-01

Abstract

The present invention relates to a surfactant mixture comprising at least one surfactant of the general formula (I) R¹O-(CH₂CH(CH₂OR²)O)_p-(D)_n-(B)_m-(A)_l,-(X)_k-Y^- 1/b M^b+ (I) where R¹, R², p, D, n, B, m, A, l, X, k, Y^-, b, M^b+ are each as defined in the claims and the description. The invention further relates to processes for mineral oil production by means of Winsor type III microemulsion flooding using a surfactant formulation comprising the surfactant mixture.

Description

Process for the production of crude oil using surfactants based on anionic alkylalkoxylates, which have been built up from glycidyl ethers

description

The present invention relates to processes for crude oil production by means of Winsor type III microemulsion flooding, in which an aqueous surfactant formulation comprising at least one surfactant of the general formula R ¹ O- (CH ₂ CH (CH ₂ OR ² ) O) _p - (D) _n - (B) _m - (A) | - (X) _k -Y-1 / b M ^{b +} (I), injected through injection wells into an oil reservoir and extracting crude oil from the deposit through production wells. The invention further relates to a surfactant mixture containing at least one surfactant of the general formula (I).

In natural oil deposits, petroleum is present in the cavities of porous reservoirs, which are closed to the earth's surface of impermeable cover layers. The cavities may be very fine cavities, capillaries, pores or the like. Fine pore necks, for example, can have a diameter of only about 1 μm. In addition to crude oil, including natural gas, a deposit contains more or less saline water.

Oil production generally distinguishes between primary, secondary and tertiary production. In the case of primary production, after the drilling of the deposit, the oil automatically flows through the borehole due to the inherent pressure of the deposit.

After the primary funding, the secondary funding is used. In secondary production, additional wells will be drilled into the oil-bearing formation in addition to the wells that serve to extract the oil, known as production wells. Through these so-called injection wells water is injected into the reservoir to maintain or increase the pressure. By injecting the water, the oil is slowly forced through the cavities into the formation, starting from the injection well, toward the production well. But this works only as long as the cavities are completely filled with oil and the viscous oil is pushed through the water in front of him. As soon as the low-viscosity water breaks through cavities, it flows from this point on the path of least resistance, ie through the channel formed, and no longer pushes the oil in front of him. By means of primary and secondary production, as a rule only about 30-35% of the quantity of crude oil in the deposit can be extracted. It is known to further increase the oil yield by measures of tertiary oil production. An overview of tertiary oil production can be found, for example, in the "Journal of Petroleum Science of Engineering 19 (1998)", pages 265 to 280. Tertiary oil extraction includes heat processes in which hot water or superheated steam is injected into the reservoir, thereby increasing the viscosity of the oil As flooding medium, gases such as CO ₂ or nitrogen can also be used.

Tertiary oil production also includes processes using suitable chemicals as auxiliaries for oil extraction. With these, the situation can be influenced towards the end of the flood and thus also promote oil that was previously held in the rock formation.

Viscous and capillary forces act on the oil trapped in the pores of the reservoir rock towards the end of the secondary production, and the ratio of these two forces to one another determines the microscopic oil removal. By means of a dimensionless parameter, the so-called capillary number N _c , the action of these forces is described. It is the ratio of the viscosity forces (velocity x viscosity of the pressing phase) to the capillary forces (interfacial tension between oil and water x wetting of the rock):

μν

σ cos0

Where μ is the viscosity of the oil mobilizing fluid, v is the Darcy velocity (flow per unit area), σ is the interfacial tension between petroleum mobilizing liquid and petroleum and Θ is the contact angle between petroleum and rock (C. Melrose, CF Brandner, J. Canadian Petr. Techn. 58, Oct.-Dec., 1974). The higher the capillary number N _c , the greater the mobilization of the oil and thus also the degree of de-oiling.

It is known that the capillary number N _c ^{'is 6,} and that it is necessary for the capillary to about 10 ^"near the end of secondary oil recovery in the range of about 10 to increase ^{from 3} to ^{10" 2} to mobilize additional mineral oil.

For this purpose, a special form of the flood process - the so-called Winsor type III microemulsion flooding - can be carried out. In Winsor Type III microemulsion flooding, the injected surfactants are expected to form a microemulsion Windsor Type III with the water and oil phases present in the reservoir. A Windsor Type III microemulsion is not an emulsion with particularly small droplets, but a thermodynamically stable, liquid mixture of water, oil and surfactants. Your three advantages are that

thereby achieving a very low interfacial tension σ between petroleum and aqueous phase,

it usually has a very low viscosity and is therefore not trapped in a porous matrix, It can be generated even at very low energy inputs and can remain stable over an infinitely long period of time (classic emulsions, however, require higher shear forces, which do not predominantly occur in the reservoir, and are only kinetically stabilized).

The microemulsion Winsor Type III is in equilibrium with excess water and excess oil. Under these conditions, the microemulsion formation, the surfactants demonstrate the oil-water interface and lower the interfacial tension σ values of <10 ^"2 mN / m (ultralow interfacial tension) is particularly preferred in. In order to achieve an optimum result, the proportion of microemulsion should Naturally, the system water microemulsion oil should be as large as possible at a defined amount of surfactant, since in this way the lower interfacial tensions can be achieved.

In this way the oil droplets can be changed in their shape (interfacial tension between oil and water is lowered so far that the state of the smallest boundary surface is no longer sought and the spherical shape is no longer preferred) and by the flood water through the capillary openings squeeze through.

If all oil-water interfaces are coated with surfactant, the Winsor Type III microemulsion will be formed if there is an excess amount of surfactant. It thus represents a reservoir for surfactants, which accomplish a very low interfacial tension between oil and water phase. By virtue of the low viscosity of the Winsor Type III microemulsion, it migrates through the porous reservoir rock during the flooding process (emulsions, however, can become trapped in the porous matrix and clog reservoirs). If the Winsor Type III microemulsion encounters an oil-water interface not yet covered with surfactant, the surfactant from the microemulsion can significantly lower the interfacial tension of this new interface and result in mobilization of the oil (for example by deformation of the oil droplets).

The oil droplets can then combine to form a continuous oil bank. This has two advantages:

Firstly, as the continuous oil bank progresses through new porous rock, the oil droplets located there merge with the bank. Furthermore, the oil-water interface is significantly reduced by the union of the oil drops to an oil bank and thus no longer required surfactant released again. The released surfactant may thereafter mobilize residual oil remaining in the formation as described above.

Consequently, Winsor Type III microemulsion flooding is an extremely efficient process and, unlike an emulsion flooding process, requires significantly less surfactant. In microemulsion flooding, the surfactants are usually optionally injected together with cosolvents and / or basic salts (optionally in the presence of chelating agents). Subsequently, a solution of thickening polymer is injected for mobility control. A Another variant is the injection of a mixture of thickening polymer and surfactants, cosolvents and / or basic salts (optionally with chelating agent) and subsequently a solution of thickening polymer for mobility control. These solutions should usually be clear to avoid blockage of the reservoir.

The requirements for surfactants for tertiary mineral oil production differ markedly from the requirements for surfactants for other applications: Suitable surfactants for tertiary oil production should be the interfacial tension between water and oil (usually approx. 20 mN / m) to particularly low values of less than 10 ^"2 mN / m to allow adequate oil mobilization at normal storage temperatures of about 15 ° C to 130 ° C and in the presence of high salty water, especially in the presence of high levels of calcium The surfactants must therefore also be soluble in strongly saline deposit water To meet these requirements, mixtures of surfactants have been frequently proposed, in particular mixtures of anionic and nonionic surfactants.

US Pat. No. 4,446,079 A describes anionic surfactants of the alkyl ether sulfate or alkyl ether sulfonate type, the hydrophobic part of the surfactants being obtained by linking two alcohols via epichlorohydrin: R ¹ O-CH ₂ CH (CH ₂ -OR ² ) O- (CH ₂ CH ₂ 0), rR ³ S0 ₃ M. R ¹ and R ² stand for a hydrocarbon radical having 1-15 carbon atoms.

EP 05231 11 B1 describes anionic surfactants of the alkyl ether sulfate or alkyl ether sulfonate type, it being possible to obtain the hydrophobic part of the surfactants by linking two alcohols over epichlorohydrin or reacting an alcohol with a long-chain epoxide: R ³ 0-CH ₂ CH (CH ₂ -OR ⁴ ) 0- (A) _p - (Y), SO ₃ H or R ³ 0 -CH ₂ CH (CH ₂ R ⁴ ) 0- (A) _p - (Y), SO ₃ H or R ⁴ 0-CH ₂ CH (CH ₂ R ³ ) 0- (A) _p - (Y) _r S0 ₃ H and salts thereof. R ³ is a hydrocarbon radical having 8 carbon atoms and R ⁴ is a hydrocarbon radical having 4-6 carbon atoms. A is ethyleneoxy or propyleneoxy, p is 0 to 1, 9.

EP 05231 12 B1 describes anionic surfactants of the alkyl ether sulfate or alkyl ether sulfonate type, where the hydrophobic part of the surfactants can be obtained by linking two alcohols via epichlorohydrin or reacting an alcohol with a long-chain epoxide: R ³ O-CH ₂ CH ( CH ₂ -OR ⁴ ) 0- (A) _p - (Y), S0 ₃ H or R ³ 0-CH ₂ CH (CH ₂ R ⁴ ) 0- (A) _p - (Y), S0 ₃ H resp R ⁴ 0 -CH ₂ CH (CH ₂ R ³ ) 0- (A) _p - (Y) _r SO ₃ H and salts thereof. R ³ is a hydrocarbon radical having 8-12 carbon atoms and R ⁴ is a hydrocarbon radical having 2-6 carbon atoms. A is ethyleneoxy or propyleneoxy.

The use parameters, such as, for example, type, concentration and the mixing ratio of the surfactants used, are adapted by the person skilled in the art to the prevailing conditions in a given oil formulation (for example temperature and salinity). As described above, the oil production is proportional to the capillary number. This is the higher, the lower the interfacial tension between oil and water. Low interfacial tensions are the more difficult to achieve the higher the average number of carbon atoms in the crude oil. For low interfacial tensions, surfactants are suitable which have a long alkyl radical. The longer the alkyl radical, the better the interfacial tensions can be reduced. However, the availability of such compounds is very limited.

The object of the invention is therefore to provide a particularly efficient surfactant or an efficient surfactant mixture for use for surfactant flooding, as well as an improved process for tertiary mineral oil production.

The object is achieved by a surfactant mixture containing at least one surfactant of the general formula (I)

R ¹ O- (CH ₂ CH (CH ₂ OR ² ) O) _p - (D) _n - (B) _m - (A), - (X) _k -Y-1 / b M ^{b +} (I) where

R ^{1 is} a linear or branched, saturated or unsaturated aliphatic hydrocarbon radical having 16 to 36 carbon atoms or an aliphatic-aromatic hydrocarbon radical having 16 to 36 carbon atoms,

R ^{2 is} a linear or branched, saturated or unsaturated aliphatic hydrocarbon radical having 8 to 22 carbon atoms,

D for butyleneoxy,

B for propyleneoxy,

A is ethyleneoxy,

X is an alkylene, hydroxyalkylene or alkenylene group having 1 to 10 carbon atoms,

M ^{b + is} a cation,

p is a number from 1 to 10,

n for a number from 0 to 99,

m for a number from 1 to 99,

I for a number from 1 to 99,

b stands for 1 or 2,

Y ^"stands for S0 ₃ ^" and k stands for 0, or Y ^"stands for a sulfonate (S0 ₃ , sulfate (OSO ₃ or carboxylate group (C0 ₂ ^" ) and k stands for 1,

the alkyleneoxy groups (CH ₂ CH (CH ₂ OR ²⁾ 0) distributed, A, B and D random, alternating distribution or be in the form of two, three, four, five or more blocks each having the same alkyleneoxy groups in any order,

and the sum I + m + n + p is in the range of 3 to 99.

A further aspect of the present invention is provided by a process for tertiary mineral oil production by means of Winsor Type III microemulsion flooding, in which an aqueous surfactant formulation is prepared. at least the surfactant of the general formula R ¹ O- (CH ₂ CH (CH ₂ OR ² ) O) _p - (D) _n - (B) _m - (A) i- (X) _k -Y-- 1 / b M ^{b +} (I) is pressed into at least one injection well in a Erdöllagerstätte, the interfacial tension between oil and water to values <0.1 mN / m, preferably to values <0.05 mN / m, more preferably Values <0.01 mN / m is lowered, and the deposit is taken through at least one production well of crude oil.

In a preferred embodiment is

m for a number from 4 to 15,

p is a number from 1 to 5, and

more than 60% of the groups (CH ₂ CH (CH ₂ OR ² ) O), A, B and D are in block form and starting in the order (CH ₂ CH (CH ₂ OR ² ) O), D, B, A of R ¹ 0 are present,

and the sum I + m + n + p is in the range of 5 to 70.

In a particularly preferred embodiment

n for a number from 2 to 15,

p is a number from 1 to 5, and

and the sum I + m + n + p is in the range of 5 to 70.

According to a further preferred embodiment

R ^{1 is} a linear or branched, saturated or unsaturated aliphatic hydrocarbon radical having 16 to 22 carbon atoms or an aliphatic-aromatic hydrocarbon radical having 16 to 22 carbon atoms,

R ^{2 is} a linear or branched, saturated or unsaturated aliphatic

Hydrocarbon radical having 8 to 22 carbon atoms, and

Y ^{a "} is selected from the group of carboxylate groups or sulfate groups k for 1.

According to a further preferred embodiment of the invention, a surfactant formulation is provided which contains, in addition to a surfactant of the general formula (I) as further surfactant, an organic sulfonate having 14 to 28 carbon atoms. More specifically, the following is to be accomplished for the invention:

In the process according to the invention for crude oil production by means of Winsor Type III microemulsion flooding described above, an aqueous surfactant formulation is used which contains at least one surfactant of the general formula R ¹ O- (CH ₂ CH (CH ₂ OR ² ) O) _p - (D) _n - (B) _m - (A) r (X) _k Y ^{a "} a / b M ^{b +} (I) and may further comprise other surfactants and / or other components.

In the context of the process according to the invention for tertiary mineral oil production by means of Winsor Type III microemulsion flooding, the use of the surfactant mixture according to the invention the interfacial tension between oil and water is lowered to values <0.1 mN / m, preferably to <0.05 mN / m, more preferably to <0.01 mN / m. Thus, the interfacial tension between oil and water will be in the range of 0.1 mN / m to 0.0001 mN / m, preferably values in the range of 0.05 mN / m to 0.0001 mN / m, more preferably values are lowered in the range from 0.01 mN / m to 0.0001 mN / m.

The radical R ¹ is a linear or branched, saturated or unsaturated aliphatic hydrocarbon radical having 16 to 36 carbon atoms or an aliphatic-aromatic hydrocarbon radical having 16 to 36 carbon atoms, and R ² is a linear or branched, saturated or unsaturated aliphatic hydrocarbon radical having 8 to 22 carbon atoms.

In the case of aliphatic-aromatic hydrocarbon radicals having 16 to 36 carbon atoms for R ¹ may be, for example, dodecylphenyl, tetradecylphenyl, 3-pentadecylphenyl, unsaturated 2-pentadecylphenyl, hexadecylphenyl, octadecylphenyl, distyrylphenyl or tristyrylphenyl.

In the case of branched radicals R ¹ or R ² , the degree of branching in the case of R ¹ or R ^{2 is} in the range from 0.1 to 5, and preferably from 0.1 to 3.5.

The term "degree of branching" is defined herein in a molecule of the alcohol minus 1 in a principally known manner than the number of methyl groups. The average degree of branching is the statistical mean of the degrees of branching of all molecules in a sample. A preferred embodiment is, however, if R ¹ is a linear or branched, saturated or unsaturated aliphatic hydrocarbon radical having 16 to 36 carbon atoms and R ^{2 is} a linear or branched, saturated or unsaturated aliphatic hydrocarbon radical having 8 to 22 carbon atoms The alcohol R ¹ OH, from which the surfactant of R ¹ OH may be, for example, C 16 -C 18 fatty alcohol, olefin alcohol, linoleyl alcohol, linolenyl alcohol, eicosanol, behenyl alcohol, erucyl alcohol, Guerbet alcohols, heptadekanol N from BASF or Neodol 67 from the company Shell.

In the case of R ² , it may be, for example, 2-ethylhexyl, isononyl, 2-propylheptyl, isodecyl, n-dodecyl, isotridecyl, n-tetradecyl, hexadecyl, isohexadecyl, isoheptadecyl, oleyl, linoleyl, linolenyl, behenyl or erucyl.

In the above formula, A is ethyleneoxy, B is propyleneoxy, and D is butyleneoxy. In a preferred embodiment, butyleneoxy is 80% and more is 1, 2-butyleneoxy.

In the general formula defined above, I, m, n and p are integers. However, it will be apparent to those skilled in the art of polyalkoxylates that this definition is is the definition of a single surfactant. In the case of the presence of surfactant mixtures or surfactant formulations which comprise several surfactants of the general formula, the numbers I, m, n and p are average values over all molecules of the surfactants, since in the alkoxylation of alcohol with ethylene oxide or Propylene oxide in each case a certain distribution of chain lengths is obtained. This distribution can be described in a manner known in principle by the so-called polydispersity D. D = M _w / M _n is the quotient of the weight average molecular weight and the number average molar mass. The polydispersity can be determined by means of the methods known to the person skilled in the art, for example by means of gel permeation chromatography.

In the above general formula I stands for a number from 1 to 99, preferably 1 to 50, particularly preferably 1 to 35.

In the above general formula, m is a number from 1 to 99, preferably 4 to 30, particularly preferably 5 to 20.

In the above general formula, n is a number from 0 to 99, preferably 1 to 20, more preferably 2 to 10. In the above general formula, p is a number from 1 to 10, preferably 1 to 5, and particularly preferably 1 to 3 ,

According to the invention, the sum I + m + n + p is a number which is in the range of 3 to 99, preferably in the range of 5 to 70, particularly preferably in the range of 15 to 65.

The ethyleneoxy (A), propyleneoxy (B), butyleneoxy (D) and (CH ₂ CH (CH ₂ OR ² ) O) blocks are randomly distributed, alternately distributed or in the form of two, three, four, five or more blocks in any order. According to a preferred embodiment of the invention, the sequence R ¹ 0, (CH ₂ CH (CH ₂ OR ²⁾ 0) block, Butylenoxyblock, Propylenoxyblock, Ethylenoxyblock is preferably in the presence of several different Alkylenoxyblöcke.

In a particularly preferred embodiment of the invention, the groups (CH ₂ CH (CH ₂ OR ² ) O), A, B and D are more than 60% in block form and in the order (CH ₂ CH (CH ₂ OR ² ) O ), D, B, A starting from R ¹ 0-, before.

In the above general formula, X is an alkylene group, hydroxylalkylene group or alkenylene group having 1 to 10, preferably 1 to 3, carbon atoms. The alkylene group is preferably a methylene, ethylene or propylene group.

The variable k is either 0 or 1. In the above general formula, Y represents a sulfonate, sulfate or carboxylate group in the case where k = 1. In the case of k = 0, Y stands for S0 ₃ ^" , which ultimately results in a surfactant with a sulfate functional end group, for example, XY ^" gives a sulfate group (S0 ₃ ^" ), an ethylenesulfonate group (CH 2 CH 2 SO 3 ^" ), a propylene sulfonate group (CH2CH2CH2SO3 ^"), 2- Hydroxypropylensulfonatgruppe (CH ₂ CH (OH) CH ₂ S0 _^3"), a Methylencarboxylatgruppe (CH2CO2 ^") or a Ethylencarboxylatgruppe (CH ₂ CH ₂ C0 _^2"). In the above formula, M ^{b + is} a cation, preferably a cation selected from the group Na ⁺ ; K \ Li \ NH \ H \ Mg ²⁺ and Ca ²⁺ (preferably Na ⁺ , K ⁺ or NH ₄ ⁺ ). Altogether b can stand for values 1, 2 or 3.

The alcohols R ¹ -OH, which serve as starting compound for the preparation of the surfactants according to the invention can be prepared by

Hydrolysis of fats and oils with water or methanol to the corresponding acids and methyl esters and subsequent hydrogenation to the primary alcohol,

Oligomerization of ethylene over aluminum catalysts and subsequent hydrolysis,

- Oligomerization of ethylene, propylene and / or butylene to corresponding olefins and subsequent reaction with CO and H ₂ ,

the alkylation of phenol with corresponding olefins,

the linkage of two aldehydes via aldol reaction or aldol condensation and subsequent hydrogenation, or

- the dimerization of alcohols of the type with elimination of water.

The glycidyl ethers CH ₂ (0) CHCH ₂ OR ² can be prepared by

Reaction of epichlorohydrin with the alcohol R ² OH to the corresponding chlorohydrin, subsequent reaction with lye (eg NaOH) and optionally final distillation, - Reaction of epichlorohydrin with the alcohol R ² OH in the presence of alkali (eg

NaOH) and a phase transfer catalyst and optionally final distillation, or

Reaction of alcohol R ² OH with allyl chloride, followed by epoxidation with peroxides and / or peracids and optionally final distillation.

Accordingly, a process for preparing surfactants of the general formula R ¹ O- (CH ₂ CH (CH ₂ OR ² ) O) p- (D) _n - (B) _m - (A) r (X) _k Y-1 / b M ^{b +} (I) wherein R ¹ , R ² , D, B, A, X, Y ^" , M ^{b +} , b, n, m, I and p are as defined above, comprising the steps of:

(a) Preparation of alcohols R ¹ OH,

(b) Preparation of glycidyl ethers CH ₂ (0) CHCH ₂ OR ² ,

(c) alkoxylation of the alcohols obtained in process step (a) with the glycidyl ether obtained in process step (b) and with alkylene oxides,

(d) optionally introducing the spacer group X, and (e) Addition of the group Y to the compounds obtained in process step (c) or (d) or sulfation of the compounds obtained in process step (c).

The preparation of the alcohols R ¹ OH in process step (a) is known in principle to a person skilled in the art.

The preparation of the glycidyl ethers in process step (b) is known in principle to the person skilled in the art. Preference is given to the reaction of alcohol R ² OH with 1-1 .5 eq epichlorohydrin in the presence of 25- 50% sodium hydroxide solution and a phase transfer catalyst at 40 to 60 ° C. As a phase transfer catalyst tertiary amines or quaternized amines can be used as tetrabutylammonium chloride. This is followed by a phase separation and optionally a purification by distillation.

The surfactants according to the general formula can be prepared in a manner known in principle by alkoxylation of corresponding alcohols R ¹ OH in process step (c). The implementation of such alkoxylations is known in principle to the person skilled in the art. It is also known to the person skilled in the art that the reaction conditions, in particular the choice of catalyst, can influence the molecular weight distribution of the alkoxylates.

The surfactants according to the general formula can preferably be prepared in process step (c) by base-catalyzed alkoxylation. In this case, the alcohol R ¹ OH in a pressure reactor with alkali metal hydroxides, preferably potassium hydroxide, or with alkali metal, such as sodium methylate, are added. By reducing the pressure (for example <100 mbar) and / or increasing the temperature (30 to 150 ° C.), water still present in the mixture can be removed. The alcohol is then present as the corresponding alcoholate. The mixture is then inertized with inert gas (for example nitrogen) and the alkylene oxide (s) is added stepwise at temperatures of 60 to 180 ° C up to a maximum pressure of 10 bar. According to a preferred embodiment, the alkylene oxide is initially metered in at 130.degree. In the course of the reaction, the temperature rises up to 180 ° C due to the released heat of reaction. According to a further preferred embodiment of the invention, the glycidyl ether is first added at a temperature in the range of 135 to 155 ° C, then added the butylene oxide at a temperature in the range of 135 to 155 ° C, then the propylene oxide at a temperature in the range of 130 to 145 ° C and then added the ethylene oxide at a temperature in the range of 125 to 145 ° C was added. At the end of the reaction, the catalyst can be neutralized, for example by addition of acid (for example acetic acid or phosphoric acid) and filtered off as required.

However, the alkoxylation of the alcohols R ¹ OH can also be carried out by other methods, for example by acid-catalyzed alkoxylation. Furthermore, it is possible to use, for example, double hydroxide clays as described in DE 4325237 A1 or it is possible to use double metal cyanide catalysts (DMC catalysts). Suitable DMC catalysts are, for example, in DE 10243361 A1, in particular in the sections To [0041] and the literature cited therein. For example, Zn-Co type catalysts can be used. To carry out the reaction, the alcohol R ¹ OH is admixed with the catalyst, the mixture is dehydrated as described above and reacted with the alkylene oxides as described. It is usually not more than 1000 ppm catalyst used with respect to the mixture and the catalyst may remain in the product due to this small amount. The amount of catalyst can typically be less than 1, 000 ppm, for example, 250 ppm or less.

The process step (d) relates to the introduction of the spacer group X, provided that this is not a simple bond. This is followed by the introduction of the anionic group as process step (e). Preferably, steps (d) and (e) occur simultaneously, so that they can be combined in one step.

The anionic group is finally introduced in process step (e). This is known in principle to the person skilled in the art. In principle, the anionic group XY is composed of ^" the functional group Y ^" , which is a sulfate, sulfonate, or carboxylate group, and optionally the spacer X together. In the case of a sulphate group, it is possible to resort, for example, to the reaction with sulfuric acid, chlorosulphonic acid or sulfur trioxide in the falling film reactor with subsequent neutralization. In the case of a sulphonate group, for example, the reaction with propanesultone and subsequent neutralization, with butanesultone and subsequent neutralization, with vinylsulfonic acid sodium salt or with 3-chloro-2-hydroxypropanesulfonic sodium salt. For the preparation of sulfonates, the terminal OH group can also be converted into a chloride, for example with phosgene or thionyl chloride, and then reacted, for example, with sulfite. In the case of a carboxylate group, for example, one can resort to the oxidation of the alcohol with oxygen and subsequent neutralization or the reaction with chloroacetic acid sodium salt. Carboxylates can also be obtained, for example, by Michael addition of (meth) acrylic acid or esters. Other surfactants

In addition to the surfactants according to the general formula (I), the formulation may additionally optionally comprise further surfactants. Preferred are organic sulfonates having 14 to 28 carbon atoms. They are, for example, anionic surfactants of the type alkylarylsulfonate or olefinsulfonate (alpha-olefinsulfonate or internal olefinsulfonate). This may be, for example, dodecylbenzene sulfonate, tetradecyl benzene sulfonate, C14 alpha olefin sulfonate, C16 alpha olefin sulfonate, C15C18 internal olefin sulfonate, C20C24 internal olefin sulfonate or C24C28 internal olefin sulfonate. However, anionic surfactants of the type petroleum sulfonate or paraffin sulfonate are also possible. Furthermore, nonionic surfactants of the type alkyl ethoxylate or alkyl polyglucoside can be used. Betainic surfactants may also be used. These other surfactants may in particular also be oligomeric or polymeric surfactants. With such polymeric cosurfactants can be advantageous to reduce the necessary to form a microemulsion amount of surfactants. Such polymeric cosurfactants are therefore also referred to as "microemulsion boosters." Examples of these Such polymeric surfactants include amphiphilic block copolymers comprising at least one hydrophilic and at least one hydrophobic block. Examples include polypropylene oxide-polyethylene oxide block copolymers, polyisobutene-polyethylene oxide block copolymers and comb polymers having polyethylene oxide side chains and a hydrophobic main chain, wherein the main chain preferably comprises substantially olefins or (meth) acrylates as building blocks. As used herein, the term "polyethylene oxide" is intended to include polyethylene oxide blocks comprising propylene oxide units as defined above Further details of such surfactants are disclosed in WO 2006/131541 A1.

Process for the extraction of oil

In the method according to the invention for the production of crude oil, a suitable aqueous formulation of the surfactants is pressed according to the general formula by at least one injection well into the oil reservoir and the deposit is withdrawn through at least one production well crude oil. Of course, the term "crude oil" in this context does not mean phase-pure oil, but means the usual crude oil-water emulsions. "In general, a deposit is provided with several injection wells and multiple production wells.

The main effect of the surfactant is to reduce the interfacial tension between water and oil - desirably to values significantly <0.1 mN / m. Following the pressing in of the surfactant formulation, the so-called "surfactant flooding" or preferably the Winsor type III "microemulsion flooding", water can be injected into the formation ("water flooding") or preferably a higher-viscosity aqueous solution of a strong one to maintain the pressure thickening polymer ("polymer flooding"). However, there are also known techniques by which the surfactants are first allowed to act on the formation. Another known technique is the injection of a solution of surfactants and thickening polymers followed by a solution of thickening polymer. The person skilled in the art knows details of the technical implementation of "surfactant flooding", "flooding" and "polymer flooding" and applies a corresponding technique depending on the nature of the deposit.

For the process according to the invention, an aqueous formulation which contains surfactants of the general formula is used. In addition to water, the formulations may optionally also comprise water-miscible or at least water-dispersible organic or other agents. Such additives serve in particular to stabilize the surfactant solution during storage or transport to the oil field. However, the amount of such additional solvents should as a rule not exceed 50% by weight, preferably 20% by weight. In a particularly advantageous embodiment of the invention, only water is used for formulation. Examples of water-miscible solvents include, in particular, alcohols such as methanol, ethanol and propanol, butanol, sec-butanol, pentanol, butyl ethylene glycol, butyl diethylene glycol or butyl triethylene glycol. In a preferred embodiment of the invention, the surfactants of the general formula R ¹ O- (CH ₂ CH (CH ₂ OR ² ) O) _p - (D) _n - (B) _m - (A) i - (X) _k Y ^{a "} 1 / b M ^{b +} (I) in the formulation ultimately serving for injection into the deposit, which constitutes the major component among all surfactants, and is more preferably at least 25%, more preferably at least 30% by weight, most particularly preferably at least 40% by weight and completely, very particularly preferably at least 50% by weight of all surfactants used.

The mixture used according to the invention can preferably be used for the surfactant flooding of deposits. It is particularly suitable for Winsor type III microemulsion flooding (flows in the Winsor III range or in the area of existence of the bicontinuous microemulsion phase). The technique of microemulsion flooding has already been described in detail at the beginning.

In addition to the surfactants, the formulations may also contain other components, such as, for example, C ₄ -C ₈ -alcohols and / or basic salts (so-called "alkaline surfactant flooding") .For such additives, for example, the retention in the formation can be reduced basic salts such as NaOH and Na ₂ C0 ₃ are suitable Optionally, the basic salts are used together with complexing agents such as EDTA or with polycarboxylates the ratio of the alcohols is with respect to the used total amount of surfactant is generally at least 1:.. 1 - however, it may The amount of basic salts may typically range from 0.1% to 5% by weight.

The deposits in which the process is used, as a rule, have a temperature of at least 10 ° C., for example 10 to 150 ° C., preferably a temperature of at least 15 ° C. to 120 ° C. The total concentration of all surfactants together is 0.05 to 5 wt .-% with respect to the total amount of the aqueous surfactant formulation, preferably 0.1 to 2.5 wt .-%. The person skilled in the art will make a suitable choice depending on the desired properties, in particular depending on the conditions in the petroleum formation. It will be appreciated by those skilled in the art that the concentration of surfactants may change upon injection into the formation because the formulation may mix with formation water or absorb surfactants also on solid surfaces of the formation. It is the great advantage of the mixture used according to the invention that the surfactants lead to a particularly good lowering of the interfacial tension. It is of course possible and also advisable to first produce a concentrate which is diluted on site to the desired concentration for injection into the formation. As a rule, the total concentration of the surfactants in such a concentrate is 10 to 70% by weight. The following examples are intended to explain the invention in more detail: Part I: Synthesis of surfactants

General Procedure 1: Synthesis of glycidyl ether

In a 2L flask, the alcohol (1 eq.) Submitted and optionally melted at 50 ° C. Sodium hydroxide (50% in water, 4.75 eq) and dimethylcyclohexylamine (1250 ppm) are added and heated to 50 ° C. with stirring. Epichlorohydrin (1 .5 eq) is added at 50 ° C within one hour with stirring. The reaction mixture is stirred for a further 5 hours at 50.degree. Subsequently, water is added and the organic phase separated. The crude product is purified by distillation. General Procedure 2: Alkoxylation by KOH Catalysis

In a 21 autoclave, the alcohol (1, 0 eq) to be alkoxylated is optionally mixed with an aqueous KOH solution containing 50% by weight of KOH. The amount of KOH is 0.2 wt .-% of the product to be produced. With stirring, the mixture is dehydrated at 100 ° C and 20 mbar for 2 h. The mixture is then flushed three times with N ₂ , a pre-pressure of about 1, 3 bar N _{2 is} set and the temperature is increased to 120 to 130 ° C. The glycidyl ether is metered in so that the temperature remains between 135 ° C and 160 ° C. The alkylene oxide is metered in such that the temperature remains between 135 ° C to 145 ° C (for ethylene oxide) and 135 to 145 ° C (for propylene oxide) and 135 to 145 ° C (for 1, 2-butylene oxide) , The mixture is then stirred for 5 h at 125 to 145 ° C, rinsed with N ₂ , cooled to 70 ° C and the reactor emptied. The basic raw product is neutralized with acetic acid. Alternatively, the neutralization can be carried out with commercially available Mg silicates, which are then filtered off. The bright product is characterized by means of a 1 H-NMR spectrum in CDCl 3, a gel permeation chromatography and an OH number determination, and the yield is determined. General Procedure 3: Sulfation by means of chlorosulfonic acid

In a round-bottomed flask, the alkyl alkoxylate (1, 0 eq) to be sulfated is dissolved in 1.5 times the amount of dichloromethane (on a weight percent basis) and cooled to 5-10 ° C. Thereafter, chlorosulfonic acid (1, 1 eq) is added dropwise so that the temperature does not exceed 10 ° C. The mixture is allowed to warm to room temperature and stir for 4 h at this temperature under N ₂ stream before the above reaction mixture into a half-volume aqueous NaOH solution at max. 15 ° C is dropped. The amount of NaOH is calculated so as to give a slight excess with respect to the chlorosulphonic acid used. The resulting pH is about pH 9 to 10. The dichloromethane is added under a slight vacuum on a rotary evaporator at max. 50 ° C away.

The product is characterized by 1 H-NMR and determines the water content of the solution (about 70%).

For the synthesis, the following alcohols were used. Alcohol description

R ¹ OH

C16C18-OH Commercially available fatty alcohol mixture consisting of linear

Ci ₆ H ₃₃ -OH and Ci ₈ H ₃₇ -OH

C32-OH Commercially available guerbet alcohol C32H65-OH, purity> 98%

The following glycidyl ether was used for the synthesis.

R ² description

2-ethylhexyl Commercially available 2-ethylhexyl glycidyl ether from Aldrich

Application testing

With the obtained surfactants, the following tests were carried out to evaluate their suitability for tertiary mineral oil production. Description of the measuring methods

Interfacial tension

Interfacial tensions were measured directly by spinning drop methods on dead crude oils (API ca. 14) and saline injection waters at the respective deposit temperatures. For this purpose, a surfactant solution described in more detail in the test results was used, combined with a cosolvent (butyldiethylene glycol) and a water hardness-binding agent (chelate). An oil drop was added to this at the reservoir temperature and the interfacial tension was read after 1-2 hours.

test results

TABLE 1 Interfacial tensions of dead crude oil (approx. 14 ° API) at 20 ° C

a) Butyldiethylenglykol

b) polyacrylic acid sodium salt

c) surfactant prepared by alkoxylation of C16C18 fatty alcohol with 7 eq propylene oxide and by subsequent sulfation

d) surfactant prepared by alkoxylation of C16C18 fatty alcohol with 7 eq butylene oxide, 7 eq propylene oxide and 10 eq ethylene oxide and subsequent sulfation

e) paraffin below Ifonat from Clariant

f) surfactant prepared by alkoxylation of C32-guerbet alcohol with 7 eq butylene oxide, 7 eq propylene oxide and 10 eq ethylene oxide and subsequent sulfation

g) surfactant from BASF produced by alkoxylation of C10-guerbet alcohol with 14 eq of ethylene oxide

h) surfactant of the formula (I) where R ¹ = nCi ₆ H ₃₃ , n-Ci ₈ H ₃₇ , R ² = 2-ethylhexyl, p = 1, n = 7, m = 7, l = 10, k = 0 , Y ^" = S0 ₃ ^" , M ⁺ = Na ⁺

As can be seen in Table 1 in Comparative Example C1, a standard system based on C16C18-7P04 sulphate provides an interfacial tension of 0.0173 mN / m on the crude dead oil. Advantage of this system is the good availability of the surfactant, as the underlying C16C18 fatty alcohol is present in large quantities (about 200,000 to / y). It is known from the literature (for example T. Sottmann, R. Strey "Microemulsions", Fundamentals of Interface and Colloid Science 2005, Volume V, chapter 5) that the interfacial tension increases the longer the oil used is. In order to obtain low interfacial tensions on heavy oils, therefore, a surfactant with a longer hydrophobic part is necessary. By extending the hydrophobic range of the surfactant by incorporation of BuO succeeds - as can be seen in Comparative Example V2 - a further reduction in the interfacial tension, but a value of below 0.01 mN / m could not be achieved.

This is achieved by using a surfactant based on a very long-chain alcohol such as e.g. of a purified guerbet alcohol with 32 C atoms purified by distillation: in comparison example V3 a value of 0.0063 mN / m could be achieved.

To build up such surfactants requires alcohols which should have 30 or more carbon atoms. Linear or weakly branched alcohols in this C chain region (e.g., Ziegler alcohols through ethylene oligomerization and subsequent introduction of the alcohol group) are available only in extremely small quantities and are not suitable for tertiary mineral oil production.

The only known alcohols on the market are long-chain Guerbet alcohols. These are prepared by dimerization of alcohols with the elimination of water and are primary alcohols with a branch in the 2-position. However, this dimerization is more difficult the longer the alcohol used, ie the conversion rates are not complete (in Guerbet alcohols with more than 28 carbon atoms, they are usually only 70%). If you want Guerbet alcohols, which have more than 30 carbon atoms and purities> 70%, it requires a distillation to remove the low molecular weight alcohol. This complicates and increases the cost of production. Surprisingly, it has been found that surfactants composed of easily accessible shorter-chain fatty alcohols are even better, if they are additionally based on glycidyl ethers of shorter-chain alcohols. Example 5 shows that even the values from V3 and V4 could be undercut by a factor of 3 and 2, respectively. Here (example 5) extremely low interfacial tensions of 0.0023 mN / m could be achieved.

Claims

claims

Surfactant mixture comprising at least one surfactant of the general formula (I)

D for butyleneoxy,

B for propyleneoxy,

A is ethyleneoxy,

M ^{b + is} a cation,

p is a number from 1 to 10,

n for a number from 0 to 99,

m for a number from 1 to 99,

I for a number from 1 to 99,

b stands for 1 or 2,

Y is ^" S0 ₃ ^" and k is 0, or Y ^"is a sulfonate (S0 ₃ , sulfate (OSO ₃ or carboxylate group (CO ₂ ^" ) and k is 1,

the alkyleneoxy groups (CH ₂ CH (CH ₂ OR ² ) 0), A, B and D are randomly distributed, alternately distributed or in the form of two, three, four, five or more blocks each having the same alkyleneoxy groups in any order,

and the sum I + m + n + p is in the range of 3 to 99.

A surfactant mixture according to claim 1, wherein

m for a number from 4 to 15,

p is a number from 1 to 5,

the alkyleneoxy groups (CH ₂ CH (CH ₂ OR ² ) 0), A, B and D more than 60% in the form of two, three, four, five or more blocks each having the same alkyleneoxy groups in the order (CH ₂ CH (CH ₂ OR ²⁾ 0), D, B, A, R ^1, starting from 0, are present, and the sum I + m + n + p is in the range of 5 to 70 wt.

A surfactant mixture according to claim 1 or 2, wherein

n for a number from 2 to 15,

p is a number from 1 to 5,

the alkyleneoxy groups (CH ₂ CH (CH ₂ OR ² ) 0), A, B and D more than 60% in the form of two, three, four, five or more blocks each having the same alkyleneoxy groups in the Order (CH ₂ CH (CH ₂ OR ² ) 0), D, B, A, starting from R ¹ 0, are present, and the sum I + m + n + p in the range of 5 to 70.

A surfactant mixture according to any one of claims 1 to 3, wherein

R ^{2 is} a linear or branched, saturated or unsaturated aliphatic hydrocarbon radical having 8 to 22 carbon atoms, and

Y ^"is a carboxylate group or a sulfate group and k is 1 each.

Surfactant mixture according to one of claims 1 to 4, wherein as an additional surfactant, an organic sulfonate having 14 to 28 carbon atoms is contained.

Process for oil production by means of Winsor Type III microemulsion flooding, in which an aqueous surfactant formulation containing at least one surfactant of the general formula (I) to reduce the interfacial tension between oil and water to <0.1 mN / m injected through at least one injection well into a Erdöllagerstätte and the Deposited by at least one production well crude oil, characterized in that the aqueous surfactant formulation comprises at least one surfactant of the general formula (I), wherein at

R ¹ O- (CH ₂ CH (CH ₂ OR ² ) O) _p - (D) _n - (B) _m - (A), - (X) _k -Y-1 / b M ^{b +} (I),

D for butyleneoxy,

B for propyleneoxy,

A is ethyleneoxy,

X is an alkylene, hydroxyalkylene or alkenylene having 1 to 10 carbon atoms,

M ^{b + is} a cation,

p is a number from 1 to 10,

n for a number from 0 to 99,

m for a number from 1 to 99,

I for a number from 1 to 99,

b stands for 1 or 2,

Y ^"is S0 ₃ ^" and k is 0, or Y ^"is a sulfonate (S0 ₃ , sulfate (OSO ₃ or carboxylate group (C0 ₂ ^" ) and k is 1, the alkyleneoxy groups (CH ₂ CH (CH ₂ OR ² ) O), A, B and D are randomly distributed, alternately distributed or in the form of two, three, four, five or more blocks each having the same alkyleneoxy groups in any order,

and the sum I + m + n + p is in the range of 3 to 99.

7. The method according to claim 6, wherein

m for a number from 4 to 15,

p is a number from 1 to 5,

the alkyleneoxy groups (CH ₂ CH (CH ₂ OR ² ) 0), A, B and D to more than 60% in the form of two-, three-, four-, five or more blocks each having the same alkyleneoxy groups in the

Order (CH ₂ CH (CH ₂ OR ² ) 0), D, B, A, starting from R ¹ 0, are present, and the sum I + m + n + p in the range of 5 to 70.

8. The method according to claim 6 or 7, wherein

n for a number from 2 to 15,

p is a number from 1 to 5,

9. The method according to any one of claims 6 to 8, wherein

Y ^"represents a carboxylate group or a sulfate group and k each represents 1. 10. A process according to any one of claims 6 to 9, wherein the further surfactant is an organic sulfonate having 14 to 28 carbon atoms.

1 1. A method according to any one of claims 6 to 10, wherein

R ^{2 is} 2-ethylhexyl.

12. The method according to any one of claims 6 to 10, wherein

R ^{2 is} 2-propylheptyl.

13. The method according to any one of claims 6 to 10, wherein

R ^{2 is} n-dodecyl or n-tetradecyl or n-dodecyl and n-tetradecyl.

14. The method according to any one of claims 6 to 10, wherein

R ^{2 is} oleyl.

15. The method according to any one of claims 6 to 14, wherein the concentration of all surfactants taken together 0.05 to 5 wt .-% with respect to the total amount of the aqueous Tensidformu- tion.