WO2011110503A1

WO2011110503A1 - Method for producing crude oil using surfactants based on butylene oxide-containing alkyl alkoxylates

Info

Publication number: WO2011110503A1
Application number: PCT/EP2011/053321
Authority: WO
Inventors: Christian Bittner; Günter OETTER; Jack Tinsley; Christian Spindler; Gabriela ALVAREZ-JÜRGENSON; Sophie Maitro-Vogel
Original assignee: Basf Se
Priority date: 2010-03-10
Filing date: 2011-03-04
Publication date: 2011-09-15
Also published as: ECSP12012146A; EP2545136A1; KR20130016266A; CA2791119C; MX2012010276A; CN104726084A; BR112012022670A2; RU2012142936A; RU2563642C2; MX340884B; AR080479A1; MY161638A; CA2791119A1; CN102791824A; AU2011226215A1; JP2013528720A; EA201401362A1; CN102791824B

Abstract

The invention relates to a method for producing crude oil by means of Winsor type III microemulsion flooding, wherein an aqueous surfactant formulation which comprises at least one ionic surfactant of general formula R¹-O-(D)_n-(B)_m-(A)_I-XY^- M⁺ is forced though injection wells into a mineral oil deposit and crude oil is removed from the deposit through production wells.

Description

Process for the production of crude oil using surfactants based on butylene oxide-containing alkyl alkoxylates

description

The invention relates to processes for crude oil production, by means of Winsor type III microemulsion flooding, in which an aqueous surfactant formulation containing at least one ionic surfactant of the general formula R ¹ -O- (D) _n - (B) _m - (A), - XY-M ⁺ , injected through injection wells in a Erdöllagerstatte and the production site boring crude oil takes. The invention further relates to ionic surfactants according to the general formula and to processes for the preparation of these.

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 can have, for example, 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 primary production, after drilling the deposit, petroleum automatically streams through the borehole due to the inherent pressure of the deposit.

After the primary funding, therefore, the secondary funding is used. In secondary production, in addition to the wells used to extract oil, the so-called production wells, additional wells will be drilled into the oil-bearing formation. 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 further includes processes in which suitable chemicals are used 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, the influence 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):

a coso

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

It is known that the capillary number ^{"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 one can carry out a special form of the flood procedure - the so-called Winsor type III microemulsion flooding. In Winsor Type III microemulsion flooding, the injected surfactants should interact with the water and water reservoirs present in the reservoir Oil phase form a microemulsion Windsor type III. A Microemulsion Windsor Type III is not an emulsion with very small droplets, but a thermodynamically stable, liquid mixture of water, oil and surfactants. Their three advantages are that it achieves 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 is formed even at very low energy inputs and can remain stable over an infinitely long period of time (classical emulsions, however, require higher shear forces, which mostly do not appear 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 particularly preferably to values of <10 ^"2 mN / m (ultralow interfacial surfactant-sion). In order to achieve the best results, should the Proportion of the microemulsion in the system water microemulsion oil with a defined amount of surfactant naturally be as large as possible, since thereby the lower interfacial tensions can be achieved.

In this way, the oil droplets in shape change (interfacial tension between oil and water is lowered so far that no longer the state of the smallest boundary surface is desired and not the spherical shape is preferred) and squeeze through the flood water through the capillary.

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 markedly lower the interfacial tension of this new interface and result in the 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: On the one hand, as the continuous oil bank advances through new porous rock, the oil droplets located there can merge with the bank.

Furthermore, the union of the oil droplets to an oil bank significantly reduces the oil-water interface, thus releasing unneeded surfactant. 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, it 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. Another variant is the injection of a mixture of thickening polymer and surfactants, cosolvents and / or basic see 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 significantly from the requirements for surfactants for other applications: Suitable surfactants for tertiary oil production are 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 and / or magnesium ions, the surfactants must therefore also be soluble in strongly saline deposit water.

Mixtures of surfactants have often been proposed to meet these requirements, in particular mixtures of anionic and nonionic surfactants.

In US 3,890,239 is a combination of organic sulfonates with alkyl alkoxylates of the type C ₈ -C ₂ o - AO - H (AO = alkylene oxide having 2 to 6 carbon atoms) with anionic surfactants of the type C ₈ -C ₂ o - AO - sulfate or C ₈ -C ₂ o - AO - sulfonate disclosed. The indication of the alkylene oxides is within the scope of the disclosure of US 3,890,239 only very general. But there are only examples that contain only EO.

US 4,448,697 claims the use of alkyl alkoxylates of the type CrC ₆ (AO) i-4o-EO> io-H in combination with an anionic surfactant. AO can be 1, 2-butylene oxide or 2,3-butylene oxide.

US Pat. No. 4,460,481 describes surfactants of the type alkylarylalkoxysulphates or -sulphonates. The alkylene oxide may be ethylene oxide, propylene oxide or butylene oxide. There is the proviso that ethylene oxide makes up the major part of the alkylene oxides. A more detailed description of butylene oxide is not found.

The use parameters, such as, for example, type, concentration and the mixing ratio of the surfactants used with one another, are therefore adapted by the person skilled in the art to the conditions prevailing in a given oil formation (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 connections is very limited.

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

Accordingly, a process for tertiary mineral oil production by means of Winsor Type III microemulsion flooding is provided, in which an aqueous surfactant formulation comprising at least one ionic surfactant is injected through at least one injection well into a crude oil deposit, the interfacial tension between oil and water to values <0.1 mN / m, is preferably lowered to values <0.05 mN / m, more preferably to values <0.01 mN / m, and the deposit is withdrawn through at least one production well crude oil, wherein the surfactant formulation at least one surfactant of the general formula

R ¹ -O- (D) _n - (B) _m - (A) i -XY ^" M ⁺ , wherein R ^{1 is} a linear or branched, saturated or unsaturated aliphatic and / or aromatic hydrocarbon radical having 8 to 30 carbon atoms,

A is ethyleneoxy,

B for propyleneoxy, and

D is butyleneoxy,

I for a number from 0 to 99,

m for a number from 0 to 99 and

n is a number from 1 to 99,

X is an alkyl or alkylene group having 0 to 10 carbon atoms,

M ^{+ is} a cation, and

Y ^"is selected from the group of sulfate groups, sulfonate groups, carboxylate groups and phosphate groups, wherein the groups A, B and D can be randomly distributed, alternating or in the form of two, three, four or more blocks in any order, the sum I + m + n is in the range of 3 to 99 and the proportion of 1, 2-butylene oxide based on the total amount of butylene oxide is at least 80%.

Furthermore, a surfactant mixture for crude oil production has been provided, which contains at least one ionic surfactant according to the general formula defined above.

More specifically, the following is to be accomplished for the invention:

The Winsor Type III microemulsion flooding crude oil production process according to the invention as described above employs an aqueous surfactant formulation containing at least one surfactant of the general formula. It may also include 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 interfacial tension between oil and water to values <0.1 mN / m, preferably to <0.05 mN / m, is particularly preferred due to the use of the surfactant according to the invention Lowered <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 lowered in the range from 0.01 mN / m to 0.0001 mN / m. The at least one surfactant can be subsumed under the general formula R ¹ -O- (D) _n - (B) _m - (A) i -XY ^" M ⁺ In the surfactant formulation, as a result of the preparation, several different surfactants of the general formula can also be used Formula be present.

The radical R ¹ is a straight-chain or branched aliphatic and / or aromatic hydrocarbon radical having 8 to 30 carbon atoms, preferably 9 to 30 carbon atoms, particularly preferably 10 to 28 carbon atoms.

According to a particularly preferred embodiment of the invention, the radical R ^{1 is} iso-Ci ₇ H ₃₅ - or a commercial fatty alcohol _mixture consisting of linear Ci ₆ H _33- and Ci ₈ H ₃₇ - or derived from the commercially available Ci ₆ -Guerbetalkohol 2-hexyldecyl -1 -ol or derived from the commercially available C ₂ 4-Guerbet alcohol 2-decyl-tetradecanol or derived from the commercially available C ₂ 8-Guerbet alcohol 2-dodecyl-hexadecanol.

N = 3 to 10 and m = 5 to 9 are particularly preferred for linear alcohols, while n = 2 to 10 and m = 5 to 9 for branched alcohols. In each case, D is more than 80% 1, 2-butylene oxide and that the alkylene oxides starting from the alcohol have the sequence D - B - A. The alkylene oxides are more than 90% arranged in blocks.

Particular preference is given to a straight-chain or branched aliphatic hydrocarbon radical, in particular a straight-chain or branched aliphatic hydrocarbon radical having from 10 to 28 carbon atoms.

A branched aliphatic hydrocarbon radical generally has a degree of branching of from 0.1 to 5.5, preferably from 1 to 3.5. The term "degree of branching" is hereby defined in a manner known in principle as the number of methyl groups in a molecule of the alcohol minus 1. The mean degree of branching is the statistical average of the degrees of branching of all molecules in a sample.

In the above formula, A has the meaning of ethyleneoxy. B is propyleneoxy and D is butyleneoxy.

In the general formula defined above, I, m and n are integers. However, it will be apparent to those skilled in the art of polyalkoxylates that this definition is the definition of a single surfactant. In the case of the presence of surfactant mixtures or surfactant formulations comprising a plurality of surfactants of the general formula, the numbers I, m and n are values for all molecules of the surfactants, since in the alkoxylation of alcohol with ethylene oxide or propylene oxide or butylene oxide, a certain distribution of chain lengths is obtained in each case. 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 general formula above, I is a number from 0 to 99, preferably 1 to 40, particularly preferably 1 to 20.

In the above general formula, m is a number from 0 to 99, preferably 1 to 20, particularly preferably 5 to 9.

In the above general formula, n is a number from 1 to 99, preferably from 2 to 30, particularly preferably from 2 to 10.

According to the invention, the sum I + m + n is a number which is in the range of 3 to 99, preferably in the range of 5 to 50, particularly preferably in the range of 8 to 39.

According to the present invention, the proportion of 1, 2-butyleneoxy based on the total amount of butyleneoxy (D) is at least 80%, preferably at least 85%, preferably at least 90%, particularly preferably at least 95% 1, 2-butyleneoxy ,

The ethyleneoxy- (A), propyleneoxy- (B) and butyleneoxy group (s) (D) are randomly distributed, alternately distributed or are in the form of two, three, four, five or more blocks in any order.

In a preferred embodiment of the invention, in the presence of a plurality of different alkyleneoxy blocks, the sequence R1, butyleneoxy block, propyleneoxy block, ethyleneoxy block is preferred. The butylene oxide used is intended

> 80% of 1, 2-butylene oxide, preferably> 90% of 1, 2-butylene oxide.

In the above general formula, X is an alkylene group or alkenylene group having 0 to 10, preferably 0 to 3, carbon atoms. The alkylene group is preferably a methylene, ethylene or propylene group. In the cited prior art, there are often no specific details regarding the description of C ₄ - epoxides. It may generally be understood as 1,2-butylene oxide, 2,3-butylene oxide, iso-butylene oxide, and mixtures of these compounds. The composition is generally dependent on the C ₄ olefin used, and to some extent on the oxidation process.

In the above general formula, Y is a sulfonate, sulfate or carboxyl group or phosphate group. In the above formula, M ^{+ is} a cation, preferably a cation selected from the group Na ⁺ ; K ⁺ , Li ⁺ , NH ₄ ⁺ , H ⁺ , g ²⁺ and Ca ² \

The surfactants according to the general formula can be prepared in a manner known in principle by alkoxylation of corresponding alcohols R ¹ -OH. 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 molar weight distribution of the alkoxylates can be influenced by the reaction conditions, in particular the choice of the catalyst. The surfactants according to the general formula may preferably be prepared 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, such as sodium, for example, sodium methylate. By reduced 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 alkoxide. 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 170 ° C due to the released heat of reaction. According to a further preferred embodiment of the invention, the butylene oxide is first added at a temperature in the range of 135 to 145 ° C, then the propylene oxide is added at a temperature in the range of 130 to 145 ° C and then 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, for example, double hydroxide clays, as described in DE 4325237 A1, can be used. or double metal cyanide (DMC) catalysts can be used. Suitable DMC catalysts are disclosed, for example, in DE 10243361 A1, in particular in sections [0029] to [0041] and in the literature cited therein. For example, Zn-Co type catalysts can be used. To carry out the reaction, the alcohol R ¹ -OH may be added with the catalyst, the mixture 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 may typically be less than 1000 ppm, for example 250 ppm or less.

The anionic group is finally introduced. This is known in principle to the person skilled in the art. In the case of a sulphate group, it is possible, for example, to resort 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-hydroxy-propanesulfonic sodium salt. 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.

Other surfactants

In addition to the surfactants according to the general formula, the formulation may additionally optionally comprise further surfactants. These are, for example, anionic surfactants of the type alkylarylsulfonate or olefinsulfonate (alpha-olefinsulfonate or internal olefinsulfonate) and / or nonionic surfactants of the type alkylethoxylate or alkylpolyglucoside. 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. Thus, such polymeric cosurfactants are also referred to as "microemulsion boosters." Examples of 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, polyisobutylene-polyethylene oxide block The main chain preferably comprises substantially olefins or (meth) acrylates as building blocks The term "polyethylene oxide" is here 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 producing crude oil, a suitable aqueous formulation of the surfactants according to the general formula is injected into the crude oil deposit through at least one injection well and crude oil is taken from the deposit through at least one production well. Of course, the term "crude oil" in this context does not mean phase-pure oil, but rather the usual crude oil-water emulsions. [0003] As a rule, a deposit is provided with several injection wells and several 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 are used in particular for stabilizing 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.

According to the invention, the proportion of surfactants according to the general formula is at least 30% by weight with respect to the proportion of all surfactants present, that is to say the surfactants according to the general formula and optionally existing surfactants. The proportion is preferably at least 50% by weight. 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 (flooding 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") .These additives can be used, for example, to reduce the retention in the formation The amount ratio of the alcohols with respect to the total amount of surfactant used is usually at least 1: 1 - however, a significant excess of alcohol can also be used The amount of basic salts can typically be from 0.1% by weight to 5% by weight .-% pass.

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 45% by weight.

The following examples are intended to explain the invention in more detail:

Part I: Synthesis of surfactants

General Procedure 1: Alkoxylation by KOH Catalysis (Applies to Use of EO, PO and / or 1, 2-BuO)

In a 21 autoclave, the alcohol to be alkoxylated (1, 0 eq) with an aqueous KOH solution containing 50 wt .-% KOH, added. 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 alkylene oxide is metered in such that the temperature remains between 125 ° C to 135 ° C (for ethylene oxide) and 130 to 140 ° 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 crude 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 2: Alkoxylation by means of DMC catalysis in the case of 2,3-butylene oxide

In a 21 autoclave, the alcohol (1, 0 eq) to be alkoxylated is mixed with a double metal cyanide catalyst (for example DMC catalyst from BASF Type Zn-Co) at 80 ° C. To activate the catalyst is applied at 80 ° C for 1 h about 20 mbar. The amount of DMC is 0.1% by weight and less of the product to be produced. 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 alkylene oxide is metered in such that the temperature remains between 125 ° C to 135 ° C (for ethylene oxide) and 130 to 140 ° C (for propylene oxide) and 135 to 145 ° C (for 2,3-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 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 in an aqueous NaOH solution with half volume at max. 15 ° C is dropped. The amount of NaOH is calculated so that there is a slight excess with respect to the chlorosulfonic 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.

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

Determination of SP ^*

a) principle of measurement:

The interfacial tension between water and oil was determined in a known manner by measuring the solubilization parameter SP ^* . The determination of the interfacial tension via the determination of the solubilization parameter SP ^* is a method accepted in the art for the approximate determination of the interfacial tension. The solubilization parameter SP ^* indicates how many ml of oil per ml of surfactant used is dissolved in a microemulsion (Windsor type III). The interfacial tension σ (interfacial tension, IFT) can be calculated from the approximate formula IFT "0.3 / (SP ^* ) ² if equal volumes of water and oil are used (C. Huh, J. Coli., Interf. Sc, Vol. 71, No. 2 (1979)). b) Working instructions

To determine the SP ^* , fill a 100 ml graduated cylinder with magnetic stirrer with 20 ml of oil and 20 ml of water. For this purpose, the concentrations of the respective surfactants are given. Subsequently, the temperature is gradually increased from 20 to 90 ° C, and it is observed in which temperature window forms a microemulsion. The formation of the microemulsion can be visually observed or by means of conductivity measurements. It forms a three-phase system (upper phase oil, middle phase microemulsion, lower phase water). If the upper and lower phases are the same size and no longer change over a period of 12 h, then the optimal temperature (T _opt ) of the microemulsion has been found. The volume of the middle phase is determined. From this volume, the volume of added surfactant is subtracted. The value obtained is then divided by two. This volume is now divided by the volume of added surfactant. The result is noted as SP ^* .

The type of oil and water used to determine SP ^* is determined according to the system under investigation. On the one hand petroleum itself can be used, or even a model oil such as decane. Both pure water and saline water can be used as water to better model the conditions in the oil formation. For example, the composition of the aqueous phase may be adjusted according to the composition of a particular reservoir water. Information on the aqueous phase used and the oil phase can be found below in the concrete description of the experiments.

test results

A 1: 1 mixture of decane and a NaCl solution was added with butyldiethylene glycol (BDG). Butyl diethylene glycol (BDG) acts as a cosolvent and is not included in the calculation of SP ^* . To this was added a surfactant mixture of 3 parts of alkylalkoxysulfate and 1 part of dodecylbenzenesulfonate (Lutensit A-LBN 50 ex BASF). The total surfactant concentration is given in weight percent of the total volume.

In another test, a 1: 1 mixture of decane and a NaCl solution was added with butyldiethylene glycol (BDG). Butyl diethylene glycol (BDG) acts as a cosolvent and is not included in the calculation of SP ^* . To this was added a surfactant mixture of 3 parts of alkylalkoxysulfate and 1 part of secondary alkanesulfonate (Hostapur SAS 60 ex Clariant). The total surfactant concentration is given in weight percent of the aqueous phase.

In addition, a 1: 1 mixture of southern German crude oil (API 33 °) and a NaCl solution with butyldiethylene glycol (BDG) was added. Butyldiethylene glycol (BDG) acts as a cosolvent and is not included in the calculation of SP ^* . For this purpose, a surfactant mixture of 3 parts of alkylalkoxysulfate and 1 part Dodecylbenzenesulfonate (Lutensit A-LBN 50 ex BASF) given. The total surfactant concentration is given in weight percent of the total volume.

In two further tests, a 1: 1 mixture of southern German crude oil (API 33 °) and a NaCl solution or a 1: 1 mixture of Canadian crude oil (API 14 °) and a NaCl solution were mixed with butyl diethylene glycol (BDG). Butyl diethylene glycol (BDG) acts as a cosolvent and is not included in the calculation of SP ^* . For this purpose, in each case a surfactant mixture of 3 parts of alkylalkoxysulfate and 1 part of secondary alkanesulfonate (Hostapur SAS 60 ex Clariant) was added. The total surfactant concentration is given in each case in percent by weight of the aqueous phase.

The results of surfactants based on linear or branched alcohols are shown in Tables 1 to 7.

Table 1 Tensides based on linear Ci ₆ Ci ₈ alcohol

Eg Alkyl-AO-S0 ₄ Na: Surfactant BDG NaCI Topt SP * IFT Ci ₂ H ₂₅ Ph-S0 ₃ Na = 3: 1 [%] [%] [%] [° C] [mN / m]

V1 Ci ₆ Ci ₈ - PO-S0 ₄ Na 2.5 2 5 48 13.3 0.0017

V2 Ci ₆ Ci ₈ - PO-S0 ₄ Na 2.5 2 4 60 17.8 0.0009

V3 Ci ₆ Ci ₈ -9PO-S0 ₄ Na 2.5 2 5 52 15.5 0.0012

V4 Ci ₆ Ci ₈ -9PO-S0 ₄ Na 2.5 2 4 67 17.8 0.0009

5 Ci ₆ Ci8-2 "1,2-BuO" -7 PO - 2.5 2 5 47 16 0.0012

S0 ₄ Na

6 Ci ₆ Ci8-2 "1,2-BuO" -7 PO - 2.5 2 4 65 16.5 0.0011

S0 ₄ Na

V7 Ci ₆ Ci8-7 PO-2 "1,2-BuO" - 2.5 2 4 46 11.8 0.0022

S0 ₄ Na

V8 Ci ₆ Ci8-7 PO-2 "1,2-BuO" - 2.5 2 3 68 14.3 0.0015

S0 ₄ Na

V9 Ci ₆ Ci ₈ -9PO-S0 ₄ Na 1.25 2 5 52 14 0.0015

V10 Ci ₆ Ci ₈ -9PO-S0 ₄ Na 1.25 2 4 67 13 0.0018

11 Ci ₆ Ci8-2 "1,2-BuO" -7 PO - 1.25 2 3.35 72 15 0,0013

S0 ₄ Na

V12 Ci ₆ Ci8- 2 "2,3-BuO" - 7 PO - 1.25 2 4.5 74 8 0.0047

S0 ₄ Na

13 Ci ₆ Ci8-3 "1,2-BuO" -7 PO - 1.25 2 3 67 23.5 0.0005

S0 ₄ Na

14 Ci ₆ Ci8-5 "1,2-BuO" -7 PO - 1.25 2 2 77 34.5 0.0003

S0 ₄ Na

15 Ci ₆ Ci8-5 "1,2-BuO" -7 PO - 1.25 2 2.15 71 35.5 0.0002

S0 ₄ Na

16 Ci ₆ Ci8-5 "1,2-BuO" -7 PO - 1.25 2 2.5 49 30.5 0.0003

S0 ₄ Na As can be seen in Table 1 on the basis of Examples V1 and V3 or V2 and V4, there are few differences in the SP * between Ci ₆ Ci ₈ - 7 PO sulphate and Ci ₆ Ci ₈ - 9 PO sulphate. It should be noted that a comparison with similar T _opt is performed to exclude temperature effects. These can have considerable influence on surfactants with nonionic elements.

If now BuO-containing Ci ₆ Ci ₈ -alkoxysulfate used, then surprising results. Examples 5 and 6 show that the incorporation of two 1,2-butylene oxide units between the Ci ₆ Ci ₈ fatty alcohol and the seven propylene oxide units leads to a surprisingly stable SP * = 16, whether at 47 ° C or at 62 ° C , At reduced total surfactant concentration, a similar picture results. In Example 1 1, at 72 ° C., the SP * is 15. Pure PO-containing compounds having the same degree of alkoxylation show greater fluctuations (V3 and V4) or fall slightly more strongly in SP * when the total surfactant concentration is reduced (V9 and V10).

An arrangement of 1, 2-butylene oxide between the propylene oxide block and the sulfate group as seen in Comparative Examples V7 and V8, however, is less favorable. SP * is at a slightly lower level and fluctuates more when considering different temperatures.

Significantly worse is the use of 2,3-butylene oxide. As can be seen in V12, the SP * with SP * = 8 is almost halved and thus worse than alkyl propoxy sulfates with the same degree of alkoxylation (V9). Surprisingly, not only the number of carbon atoms but also the spatial arrangement of them has a great influence on the ability of the surfactants to lower the interfacial tension. An unfavorable arrangement, as in the case of 2,3-butylene oxide, even has a disturbing effect and gives worse values than with corresponding surfactants without alkylene oxide with 4 C atoms. This was not described in US Pat. No. 3,890,239 or US Pat. No. 4,448,697.

Interestingly, there is a sudden improvement as soon as the content of 1,2-butylene oxide linear units in the linear Ci ₆ Ci ₈ fatty alcohol is three or more. In example 13, the incorporation of three such units leads to an increase in SP * to 23.5. This can be increased even further by going to 5 units (Example 14-16). Here SP * is even over 30. TABLE 2 Surfactants based on branched iCi ₇ -alcohol

A similar picture is given in Table 2. Here, alkylalkoxy sulfates based on the branched iCi ₇ alcohol were used to demonstrate that it is an effect not due to linear alcohols alone.

Comparative Example C1 and Example 2 show very clearly that with surfactants having the same degree of alkoxylation, the use of 1,2-butylene oxide instead of propylene oxide is of considerable advantage. At a similar temperature, the SP ^{* is} three times larger. Also, the placement of the 1, 2 BuO directly on the alkyl moiety (as seen in Examples 5 and 6) provides lower interfacial tensions than any other arrangement such as in Example 4.

Table 3 Surfactants based on branched Ci ₆ -Guerbet alcohol compared to

Ci ₆ Ci ₈ alcohol-based surfactants

Eg Alkyl - AO - S0 ₄ Na: Surfactant BDG NaCI Topt SP * IFT Ci ₂ H ₂ 5Ph - S0 ₃ Na = 3: 1 [%] [%] [%] [° C] [mN / m]

V1 Ci ₆ Ci8 - 9 PO - S0 ₄ Na 1.25 2 4 67 13 0.0018

2 Ci ₆ Ci8 - 2 "1, 2-BuO" - 7 PO - 1.25 2 3.35 72 15 0.0013

S0 ₄ Na

3 Cie Guerbet 2 "1, 2 BuO" - 7 1.25 2 2.85 68 27.5 0.0004

PO - S0 ₄ Na

4 Cie Guerbet - 2 "1, 2-BuO" - 7 1.25 2 3 64 23.5 0.0005

PO - S0 ₄ Na

5 Ci ₆ Ci8- 3 "1, 2-BuO" - 7 PO - 1.25 2 3 67 23.5 0.0005

S0 ₄ Na

6 Cie Guerbet - 7 "1, 2-BuO" - 7 0.40 2 4 5 73 31 0,0003

PO - 10 EO - SO ₄ Na

V7 Cie Guerbet - 7 PO - S0 ₄ Na 1.25 2 5 70 6 0.0083

V8 Cie Guerbet - 9 PO - S0 ₄ Na 1.25 2 4 71 9 0.0037 V9 Cie Guerbet - 6 PO - S0 ₄ Na 1.25 2 5 64 5 0.0120

V10 Ci ₆ Ci8 - 6 PO - S0 ₄ Na 1.25 2 5 64 10 0.0030

1 1 Cie Guerbet 1 "1, 2-BuO" - 7 1.25 2 3.3 73 10.25 0.0029

PO - S0 ₄ Na

As shown in Table 3, a similar picture applies here as well. If a surfactant based on a linear alcohol contains more than two 1, 2 BuO units, there is a significant jump in the SP ^* and thus a lowering of the interfacial tension. Example 2 compared to Examples 3 and 4 show the difference between the surfactant based on the linear Ci ₆ Ci ₈ -alcohol and the surfactant based on the branched Ci ₆ -Guerbet- alcohol. In the case of the Guerbet-based surfactant, incorporation of 2 units of 1,2-butylene oxide achieves a significantly better SP ^* than that of a linear alcohol of similar chain length. By incorporating a further amount of 1,2-butylene oxide in the case of the linear alcohol, however, as shown in Example 5, an approximately identical SP ^* level as in Example 4 can be achieved.

In Example 6 it can be seen that the incorporation of 10 EO between sulfate group and PO block, the additional hydrophobicity of the 7-BuO block can be almost compensated, so that a comparison with Comparative Example V1 under similar conditions (similar salinity, similar Temperature T _opt ) can make.

Without the incorporation of 1, 2-butylene oxide, as can be seen in Comparative Examples V7 and V8, it is only an average surfactant. Example 1 1 shows that the incorporation of 1 eq 1, 2 BuO gives only some improvement in SP ^* . Only by incorporation of 2 eq 1, 2 BuO results in the C16 Guerbet-based surfactant, a significant improvement (Example 3). Table 4 Experiments with southern German crude oil

As can be seen in Table 4, even with crude oil, a nearly identical picture results in comparison to the experiments with model oil decane. Comparative Example C1 gives significantly lower SP ^* values and thus higher interfacial tensions than the BuO-containing Surfactant in Example 2 at comparable temperature. Comparative Example C3 and Example 4 show in a similar manner the advantage of 1,2-butylene oxide.

Table 5 Experiments with decane at similar temperature and salinity

The aqueous surfactant solutions mixed with BDG are clearly dissolved under the optimum conditions (salinity and T _opt ) and, when added to the oil, give a three-phase system (Winsor type III). As can be seen in Table 5, the optimal conditions (salinity and T _opt ) are very close to each other. If the degree of alkoxylation is correctly matched, a surfactant is obtained as in Example 2 which has a similar hydrophilic-hydrophobic balance to the surfactant in Comparative Example C1. However, SP ^* is much larger in Example 2. Correspondingly lower is the interfacial tension.

Table 6 Tests with southern German oil (API 33 °) at similar temperature and salinity

The aqueous surfactant solutions mixed with BDG are clearly dissolved under the optimum conditions (salinity and T _opt ) and, when added to the oil, give a three-phase system (Winsor type III). As can be seen in Table 6, the optimal conditions (salinity and T _opt ) are very close together. If the degree of alkoxylation is correctly matched, a surfactant is obtained as in Example 2, which has a similar hydrophilic-hydrophobic balance to the surfactant in Comparative Example C1. However, SP ^* is much larger in Example 2. Correspondingly lower is the interfacial tension. Table 7 Canadian oil (API 14 °) experiments at similar temperature and salinity

The aqueous surfactant solutions mixed with BDG are clearly dissolved under the optimum conditions (salinity and T _opt ) and, when added to the oil, give a three-phase system (Winsor type III). As can be seen in Table 7, the optimal conditions (salinity and T _opt ) are very close together. If the degree of alkoxylation is correctly matched, a surfactant is obtained as in Example 2 which has a similar hydrophilic-hydrophobic balance to the surfactant in Comparative Example C1. However, SP ^* is much larger in Example 2. Correspondingly lower is the interfacial tension.

Claims

claims

1 . A method for oil production, by Winsor type III microemulsion flooding, wherein an aqueous surfactant formulation comprising at least one ionic surfactant to lower the interfacial tension between oil and water to <0.1 mN / m, injected through at least one injection well into a Erdöllagerstätte and the deposit by at least a production well crude oil is characterized in that the surfactant formulation at least one surfactant of the general formula

R ¹ -O- (D) _n - (B) _m - (A) i -XY ^" M ⁺ , wherein

R ^{1 is} a linear or branched, saturated or unsaturated aliphatic and / or aromatic hydrocarbon radical having 8 to 30 carbon atoms,

A is ethyleneoxy,

B for propyleneoxy, and

D is butyleneoxy,

I for a number from 0 to 99,

m for a number from 0 to 99 and

n is a number from 1 to 99,

X is an alkyl or alkylene group having 0 to 10 carbon atoms,

M ^{+ is} a cation, and

The method of claim 1, wherein the sum of I + m + n is in the range of 5 to 50.

3. The method of claim 1 or 2, wherein the proportion of 1, 2-butylene oxide based on the total amount of butylene oxide, at least 90%.

4. The method according to any one of claims 1 to 3, wherein the surfactant of the general formula 2 to 15 contains 1, 2-butylene oxide units. A method according to any one of claims 1 to 4, wherein the concentration of all surfactants taken together is 0.05 to 5% by weight relative to the total amount of the aqueous surfactant formulation.

Method according to one of claims 1 to 5, wherein

m for a number from 5 to 9 and

n is a number from 2 to 10, and

Y ^"is selected from the group of sulphate groups, sulphonate groups and carboxylate groups, where groups A, B and D are more than 80% in block form in the order D, B, A, starting from R ¹ , the sum I + m + n is in the range of 7 to 49 and the proportion of the 1, 2-butylene oxide based on the total amount of butylene oxide in the molecule is at least 90%.

A process according to claim 6, wherein R ^{1 is} a linear fatty alcohol having 16 or 18 carbon atoms and n is a number from 3 to 10.

A surfactant formulation comprising at least one ionic surfactant of the general formula

R ¹ -O- (D) _n - (B) _m - (A) i -XY-M ⁺ , where

A is ethyleneoxy,

B for propyleneoxy, and

D is butyleneoxy,

I for a number from 0 to 99,

m for a number from 0 to 99 and

n is a number from 1 to 99,

X is an alkyl or alkylene group having 0 to 10 carbon atoms,

M ^{+ is} a cation, and

Y ^"is selected from the group of sulfate groups, sulfonate groups, carboxylate groups and phosphate groups, where groups A, B and D may be randomly distributed, alternating or in the form of two, three, four or more blocks in any order, the sum I + m + n is in the range of 3 to 99 and the proportion of the 1, 2-butylene oxide based on the total amount of butylene oxide is at least 80%.

9. A surfactant formulation according to claim 8, wherein

m for a number from 5 to 9 and

n is a number from 2 to 10, and

10. A surfactant formulation according to claim 9, wherein R ^{1 is} a linear fatty alcohol having 16 or 18 carbon atoms n is a number from 3 to 10.

1 1. A surfactant formulation according to claims 8 to 10, characterized in that the concentration of all surfactants together is 0.05 to 5 wt.% With respect to the total amount of the aqueous surfactant formulation.

12. A surfactant of the general formula R ¹ -O- (A), (B) _m (D) _n -Xr M ⁺ , where

A is ethyleneoxy,

B for propyleneoxy, and

D is butyleneoxy,

I for a number from 0 to 99,

m for a number from 0 to 99 and

n is a number from 1 to 99,

X is an alkyl or alkylene group having 0 to 10 carbon atoms,

M ^{+ is} a cation, and

Y ^"is selected from the group of sulfate groups, sulfonate groups, carboxylate groups and phosphate groups, wherein the groups A, B and D may be randomly distributed, alternating or in the form of two, three, four or more blocks in any order, the sum I + m + n is in the range from 3 to 99 and the proportion at 1, 2- Butylene oxide based on the total amount of butylene oxide is at least 80%.

The surfactant of claim 12, wherein the sum of I + m + n ranges from 3 to 49.

14. A surfactant according to claim 12 or 13, wherein the proportion of 1, 2-butylene oxide based on the total amount of butylene oxide, at least 90%.

15. A surfactant according to any one of claims 12 to 14, wherein R ^{1 is} a linear or branched, saturated or unsaturated aliphatic and / or aromatic hydrocarbon radical having 10 to 30 carbon atoms.

16. A surfactant according to any one of claims 12 to 15, wherein

R ^{1 is} a linear fatty alcohol having 16 or 18 carbon atoms

m for a number from 5 to 9 and

n is a number from 3 to 10, and

Y ^"is selected from the group of sulfate groups, sulfonate groups and

Carboxylate groups, wherein the groups A, B and D are more than 80% in block form in the order D, B, A, starting from R ¹ , the sum I + m + n in the range of 7 to 49 and the proportion on the 1, 2-butylene oxide based on the total amount of butylene oxide in the molecule is at least 90%.