JP2013521122A - Process for producing mineral oils using a cationic surfactant having a hydrophobic block with a chain length of 6 to 10 carbon atoms - Google Patents

Abstract

The present invention is a method for producing mineral oil using Winsor type III microemulsion flooding, having the general formula R ¹ N ⁺ (R ² ) _m (R ³ ) _n (R ⁴ ) X ⁻ An aqueous surfactant formulation comprising at least one ionic surfactant is injected into a mineral oil deposit through an injection hole and crude oil is removed from the deposit through an output hole.
[Selection figure] None

Description

The present invention is a method for producing mineral oil using Winsor Type III microemulsion flooding, which has the general formula R ¹ N ⁺ (R ² ) _m (R ³ ) _n (R ⁴ ) X ⁻
A method for injecting an aqueous surfactant formulation comprising at least one ionic surfactant into a mineral oil deposit through an injection hole and removing crude oil from the deposit through an output hole.

  The invention further relates to ionic surfactants of this general formula and to a process for producing them.

  In natural mineral oil deposits, mineral oil is present in porous storage rock cavities, which are sealed to the soil surface by an impervious top layer. The cavities may be very fine cavities, capillaries, holes, or the like. The fine hole neck (fine hole constriction) may have a diameter of only 1 μm, for example. In addition to mineral oil containing natural gas, the sediment contains water with more or less salt content.

  In the production of mineral oil, a distinction is made between primary, secondary and tertiary output. In primary production, mineral oil flows through the holes after starting to drill the deposit due to the self-generated pressure of the deposit.

  Therefore, secondary extraction is performed after primary extraction. In the secondary extraction, in addition to the borehole responsible for the production of mineral oil, so-called production holes, further holes are drilled in the mineral oil-containing structure. In order to maintain the pressure or increase the pressure again, water is injected into the deposit through these so-called injection holes. As a result of the water injection, the mineral oil is slowly moved through the structure through the cavity (progressing from the injection hole and towards the production hole). However, this works as long as the cavity is completely filled with oil and the higher viscosity oil is pushed forward by the water. When fluid water is interrupted by the cavity, the water immediately flows from this point through the least resistive passage, i.e. through the formed passage and no longer pushes the oil forward.

  Primary and secondary production usually produces only about 30-35% of the amount of mineral oil present in the sediment.

It is known that the yield of mineral oil can be increased by using tertiary extraction. A review of tertiary oil production can be found, for example, in “Journal of Petroleum Science of Engineering 19 (1998)”, pages 265-280. Tertiary oil production includes, for example, thermal methods in which hot water or steam is injected into the sediment. This reduces the viscosity of the oil. The fluid medium used may likewise be a gas such as CO ₂ or nitrogen.

  Tertiary mineral oil production also includes methods in which appropriate chemicals are used as aids for oil extraction. This affects the location facing the edge of the water stream (per edge of the water stream) and, as a result, can be used to produce mineral oil that has so far been firmly held in the rock structure. it can.

  Around the end of the secondary extraction, viscous and capillary forces act on the mineral oil trapped in the pores of the sedimentary rock. The ratio of these two forces is determined by microscopic oil separation relative to each other. A dimensionless parameter, the so-called capillary number, is used to describe the action of these forces. This is the ratio of viscous force (velocity x viscosity of the phase on which the force acts) to capillary force (oil-water interfacial tension x rock wetting):

  In this equation, μ is the viscosity of the fluid that moves the mineral oil (petroleum), ν is the Darcy speed (flow rate per unit area), σ is the interfacial tension between the liquid that moves the mineral oil and the mineral oil, and θ is the mineral oil. And the contact angle between the rock and the rock (C. Melrose, CF Brandner, J. Canadian Petr. Tech. 58, Oct.-Dec., 1974). When the number of capillaries (capillary number) is high, the mobilization property of oil increases, and therefore the degree of oil extraction increases.

The number of capillaries at the end of the secondary oil production is known to be in the range of about 10 ⁻⁶ , and the number of capillaries from about 10 ⁻³ to 10 ⁻² to mobilize additional mineral oil. Need to be increased.

For this purpose, it is possible to carry out a specific form of the flooding method known as Winsor type III microemulsion flooding. In microemulsion flooding, the injected surfactant forms a Winsor type III microemulsion with the aqueous phase and the oil phase present in the sediment. The Winsor type III microemulsion is not a particularly small droplet emulsion, but a thermodynamically stable mixture of water, oil and surfactant. These three advantages are as follows:
A very low interfacial tension σ between the mineral oil and the aqueous phase is achieved,
-This usually has a very low viscosity and as a result is not trapped in the porous matrix;
-It is formed with minimal energy introduction and can remain stable over a very long period of time (contrast emulsions, in contrast, have high shear forces that do not occur primarily in reservoirs) And is only kinetically stabilized).

Winsor type III microemulsion is in equilibrium with excess water and excess oil. Under these conditions of the microemulsion formulation, the surfactant covers the oil-water interface and lowers the interfacial tension σ, more preferably to a value of <10 ⁻² mN / m (very low interfacial tension). ).

  For optimum results, the proportion of microemulsion in a water-microemulsion-oil system with a defined proportion of surfactant should be maximal in nature. This is because a corresponding lower interfacial tension is achieved.

  In this way, the shape of the oil droplets can be changed (the interfacial tension between oil and water is reduced to a certain degree, so that a minimal interfacial surface is no longer sought and Shapes are no longer preferred), and they can be driven (extruded) through the capillary opening by flooding water.

  If all the oil-water interface is covered with surfactant, a Winsor type III microemulsion is formed in the presence of an excess amount of surfactant. This therefore constitutes a reservoir for the surfactant, causing a very low interfacial tension between the oil and water phases. Due to the low viscosity Winsor type III microemulsion, it moves through the porous sedimentary rock in the flooding process (in contrast, the emulsion is trapped in the porous matrix and occludes the deposit). When the Winsor type III microemulsion encounters an oil-water interface that is not yet covered with surfactant, the surfactant from the microemulsion significantly reduces the interfacial tension of this new interface and (eg, oil Mobilization of the oil (by deformation of the droplets).

The oil droplets can then be combined into a continuous oil bank. This has two advantages:
First, when a continuous oil bank passes through a new porous rock, the oil drops present there can merge with the bank. Furthermore, the oil droplets combine to form an oil bank, thereby reducing the oil-water interface and thus no longer needing to release the surfactant again. Thus, the released surfactant can mobilize oil droplets remaining in the formulation, as described above.

  Accordingly, Winsor type III microemulsion flooding is a very effective method and requires very little surfactant compared to the emulsion flooding method. In microemulsion flooding, the surfactant is typically optionally injected with a co-solvent and / or a basic salt (optionally in the presence of a chelating agent). A concentrated (thickened) polymer solution is then injected for mobility control. In a further variation, a mixture of thickening polymer and surfactant, co-solvent, and / or basic salt (optionally with a chelating agent) is injected and then the thickening polymer The solution is injected for mobility control. These solutions are usually clear to prevent blockage of the reservoir.

The conditions required for surfactants for tertiary mineral oil extraction are significantly different from those required for surfactants for other applications: the appropriate interface for tertiary oil extraction. The activator reduces the interfacial tension between water and oil (typically about 20 mN / m) to less than 10 ⁻² mN / m (to allow sufficient mobilization of the mineral oil). Should. This is done in the presence of a normal deposition temperature of about 15 ° C. to 130 ° C. and water with a high salt content, more particularly in the presence of a high proportion of calcium and / or magnesium ions. There must be. The surfactant must therefore be soluble even in sedimentary water with a high salt content.

  In order to meet these requirements, mixtures of surfactants, particularly mixtures of anionic and nonionic surfactants, have often been proposed.

  Patent Document 1 (US Pat. No. 4,374,734) discloses the use of a cationic surfactant as an emulsion breaking agent for breaking an emulsion that is producing mineral oil. One example mentioned above is dioctyldimethylammonium chloride.

  US Pat. No. 4,596,662 discloses a combination of 30-70% glycol diester of sulfosuccinate, 30-50% propoxylated alkylamine and 0.1-4% alkylphenol ether sulfate. Alkylamines that have been propoxylated may contain 2-20 PO units and may contain alkyl groups with 1-6 carbon atoms on the nitrogen.

Patent Document 3 (DD260713A1) discloses a microemulsion formulation when C ₁₂ -C ₁₈ -alkylsulfonate sodium salt and C ₁₂ -C ₁₈ -alkyldimethylbenzylammonium chloride are used simultaneously.

  Patent Document 4 (WO93 / 04265A1) discloses a mixture of one anionic and one cationic surfactant, which can form a precipitate with a combination of surfactants. And good foaming performance. The cationic surfactant is dodecyl (bishydroxymethyl) methylammonium chloride.

  The use of parameters used, such as type, concentration, and mutual mixing ratio of the surfactants used, will thus depend on the conditions of the given oil formulation (eg temperature and salt content), and those skilled in the art Adjusted by.

  As mentioned above, mineral oil production is proportional to the number of capillaries. When the interfacial tension between oil and water is low, the number of capillaries increases. Low interfacial tension and at the same time sufficiently high solubility of the surfactant are usually difficult to achieve. This is particularly true when a basic salt that converts carboxylic acid present in crude oil into a hydrophobic surfactant cannot be added (in this case, a hydrophilic surfactant having good solubility in water). Just need to be injected). The combination of long chain cationic surfactant and long chain anionic surfactant can be precipitated as an unconverted complex or, in the case of unfavorable combinations, can be lost by decomposition into oil. The use of a cationic counter ion, such as tetraethylammonium, with an anionic surfactant is not sufficient due to high salinity. This is because the excessive amount of sodium ions is high. This is because counter ions are converted in the flooding process. In the course of the flooding process, counter ion exchange can take place.

US4374734 US4596662 DD260713A1 WO93 / 04265A1

  Accordingly, it is an object of the present invention to provide surfactants that are particularly suitable for use in surfactant flooding, or preferred microemulsion flooding, and provide an improved method for tertiary crude oil production. There is.

Accordingly, a method for producing mineral oil using Winsor type III microemulsion flooding, comprising:
An aqueous solution comprising at least one ionic surfactant to reduce the interfacial tension between oil and water to <0.1 mN / m, preferably <0.05 mNm, more preferably <0.01 mN / m. Injecting a surfactant formulation into the mineral oil deposit through at least one injection hole and removing crude oil from the deposit through at least one output hole;
The surfactant formulation has the general formula R ¹ N ⁺ (R ² ) _m (R ³ ) _n (R ⁴ ) X ⁻
(However,
R ¹ is a linear or branched, saturated or unsaturated, aliphatic and / or aromatic hydrocarbon group having 6 to 10 carbon atoms (hydrocarbyl radical). ,
R ² and R ³ are each independently ethyleneoxy, propyleneoxy and / or butyleneoxy and / or pentyleneoxy, preferably ethyleneoxy and / or propyleneoxy, and more preferably ethyleneoxy;
R ⁴ is an alkyl group having 1 to 4 carbon atoms, or a hydroxyalkyl group, a benzyl group, or a phenyl-CH ₂ —CH ₂ —, or a phenyl-CH (CH ₃ ) — group,
m is 1-8, and n is 1-8, and the sum of m + n is in the range of 2-8, and X is an anion)
There is provided a method for producing a mineral oil characterized in that it comprises at least one surfactant.

In a further preferred embodiment of the above-described method, the surfactant formulation has the general formula R ¹ N ⁺ (R ² ) _m (R ³ ) _n (R ⁴ ) X ⁻
(However,
R ¹ is a linear or branched, saturated or unsaturated aliphatic and / or aromatic hydrocarbon group having 6 to 10 carbon atoms,
R ² and R ³ are each independently a methyl group, an ethyl group, and / or a benzyl group,
R ⁴ is an alkyl group having 1 to 4 carbon atoms, or a hydroxyalkyl group, a benzyl group, or a phenyl-CH ₂ —CH ₂ —, or a phenyl-CH (CH ₃ ) — group,
n = m = 1, and X is an anion)
At least one surfactant.

  Additionally, there is provided a surfactant mixture for producing mineral oil comprising at least one ionic surfactant of the general formula described above.

The present invention is described in detail below;
In the method according to the present invention for the tertiary production of mineral oil using Winsor type III microemulsion flooding, the interfacial tension between oil and water is <0 by using the surfactant of the present invention. It is reduced to a value of .1 mN / m, preferably <0.05 mN / m, more preferably <0.01 mN / m. Therefore, the interfacial tension between oil and water is a value in the range of 0.1 mN / m to 0.0001 mN / m, preferably a value in the range of 0.05 mN / m to 0.0001 mN / m, more preferably 0. Reduced to a value in the range of .01 mN / m to 0.0001 mN / m.

  In the process according to the invention described above for producing mineral oil, an aqueous surfactant formulation (containing at least one surfactant of this general formula) is used. This may additionally contain further surfactants and / or other ingredients.

This at least one surfactant can be summarized by the general formula R ¹ N ⁺ (R ² ) _m (R ³ ) _n (R ⁴ ) X ⁻ as defined above. As a result of the production, there can be a plurality of different surfactants in the surfactant formulation that can be summarized by this general formula.

The R ¹ group is a linear or branched, aliphatic and / or aromatic hydrocarbon group having 6 to 10 carbon atoms (hydrocarbyl radical). In a preferred embodiment of the invention, the R ¹ group is a hexyl group, octyl group, 2-ethylhexyl group, isononyl group, decyl group, or 2-propylheptyl group.

In the above general formula, R ² and R ³ are each independently defined as methyl, ethyl, or benzyl, or each is an ethyleneoxy, propyleneoxy, and / or butyleneoxy group, and / or pentylene. Defined as oxy. The ethyleneoxy, propyleneoxy, and butyleneoxy groups, and the pentyleneoxy group are in a random distribution, alternating sentence distribution, or the state of 2, 3, 4, or more blocks in any desired sequence It is.

In the general formula defined above, m and n are each an integer. However, it will be clear to those skilled in the art of polyalkoxylates that this definition is in each case the definition of a single surfactant. For a mixture of surfactants or a surfactant formulation comprising a plurality of surfactants of this general formula, the numbers m and n are averages over all molecules of the surfactant. This is because alkoxylation of amines with ethylene oxide, or propylene oxide, or butylene oxide, or pentylene oxide always results in a predetermined distribution of chain length. This distribution can be described by the so-called polydispersity D known in principle. D = M _w / M _n is a value obtained by dividing the mass average molar mass by the number average molar mass. Polydispersity can be measured by methods known to those skilled in the art, such as gel permeation chromatography.

  In the above formula, m is 1 to 8, preferably 1 to 4.

  In the above formula, n is 1 to 8, preferably 1 to 4.

  According to the invention, the sum of m + n is in the range 2-8, preferably in the range 2-5.

In the general formula defined above, R ⁴ is an alkyl group having 1 to 4 carbon atoms or a hydroxyalkyl group. In a further embodiment of the invention, R ⁴ is a benzyl group, or a phenyl-CH ₂ —CH ₂ — or phenyl-CH (CH ₃ ) — group. In a preferred embodiment of the invention, R ⁴ is selected from methyl, ethyl, propyl and butyl groups.

  “Hydroxyalkyl” means an alkyl group substituted by one hydroxy group. Hydroxy-lower alkyl groups are preferred. Examples of preferred groups include: hydroxymethyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, and 2-hydroxybutyl.

In the above formula, X ⁻ is an anion, preferably an anion selected from chloride, bromide, iodide, sulfate, methyl sulfonate, carbonate, and phosphate.

  The surfactant of this general formula can in principle be produced in a known manner by alkoxylating the corresponding primary amine. The implementation of such alkoxylation is known in principle to those skilled in the art. Similarly, it is known to those skilled in the art that reaction conditions, particularly the choice of catalyst, can affect the molar mass distribution of alkoxylates.

Additional surfactants In addition to the surfactants of this general formula, the formulation may optionally additionally comprise further surfactants. Here, for example, an anionic surfactant having no alkoxy group, for example, an alkyl benzene sulfonate, an olefin sulfonate, a paraffin sulfonate, an alkyl carboxylate, an alkyl sulfate, and / or an alkyl phosphate, an anionic surfactant having an alkoxy group For example, ether sulfates (more preferably alkyl propoxy sulfates), ether sulfonates, ether carboxylates, and ether phosphates; alkyl alkoxylates such as alkyl ethoxylates, alkyl propoxy ethoxylates, or others, betaine or zwitterionic Surfactants such as alkyldimethylamine oxide may be mentioned. These further surfactants may in particular be oligomeric or polymeric surfactants. It is advantageous to use such a co-surfactant to reduce the amount of surfactant required to form a microemulsion.

  Such polymeric co-surfactants are therefore also referred to as “microemulsion boosters”. Examples of such polymeric surfactants include amphiphilic block copolymers comprising at least one hydrophilic block and at least one hydrophobic block. Examples are polypropylene oxide-polyethylene oxide block copolymers, polyisobutylene-polyethylene oxide block copolymers, and comb polymers having polyethylene oxide side chains and a hydrophobic backbone (the backbone is preferably essentially olefin or (meth) Acrylate as a monomer). The term “polyethylene oxide” here includes in each case a polyethylene oxide block comprising propylene oxide as defined above. Further details of such surfactants are disclosed in WO 2006/131541 A1.

Process for Mineral Oil Production In a method according to the invention for mineral oil production using Winsor type III microemulsion flooding, a suitable aqueous formulation of this general formula surfactant has at least one injection hole. Through and into the mineral oil deposit, and crude oil is removed from the deposit through at least one output hole. Here, the term “crude oil” naturally does not mean a single phase oil, but rather a normal crude oil-water emulsion. Usually, the deposit (deposition bed) is provided with a plurality of injection holes and a plurality of output holes. The main effect of the surfactant is to significantly reduce the interfacial tension between water and oil-desirably to a value of <0.1 mNm. After injecting a surfactant formulation, preferably known as “surfactant flooding”, or preferably microemulsion flooding, then by injecting water into the structure (“water flooding”), or preferably a strong increase. The pressure can be maintained by injecting a highly viscous aqueous solution of a viscous polymer (“polymer flooding”). However, techniques are also known by allowing the surfactant to act on the structure first. A further known technique is a technique in which a solution of a surfactant and a thickening polymer is injected, and then a solution of the thickening polymer is injected. Those skilled in the art are aware of the industrial functions of “surfactant flooding”, “water flooding” and “polymer flooding” and use appropriate techniques according to the type of deposit.

  For the process according to the invention, an aqueous formulation comprising a surfactant of this general formula is used. In addition to water, the formulation may optionally include water miscible or at least one water dispersible organic material, or other material. Such additives act in particular to stabilize the surfactant solution during storage or during transport to the oil field. However, the amount of such additional solvent should normally not exceed 50% by weight and preferably not exceed 20% by weight. In a particularly advantageous embodiment of the invention, exclusively water is used for the formulation. Examples of water miscible solvents include alcohols such as methanol, ethanol, and propanol, butanol, sec-butanol, pentanol, butylethylene glycol, butyldiethylene glycol, or butyltriethylene glycol.

  In a preferred embodiment of the invention, the aqueous surfactant formulation comprises at least one anionic surfactant of the alkyl alkoxy sulfate or alkyl alkoxy sulfonated type. This is present in aqueous surfactant formulations at a higher concentration than the described (claimed) cationic surfactant, eg, the surfactant solution is made soluble by neutralization of charge. To maintain and form a clear solution) the ratio of anionic surfactant to cationic surfactant on a molar basis is at least 5.5: 4.5, preferably at least 6: 4, more preferably at least 7: 3.

  In a preferred embodiment of the invention, the aqueous surfactant formulation comprises at least one anionic surfactant of the alkylaryl sulfonate type. This is present in the aqueous surfactant formulation at a higher concentration than the described (claimed) cationic surfactant, i.e. the surfactant solution remains soluble by charge neutralization. The ratio of anionic surfactant to cationic surfactant (to form a clear solution) on a molar basis is at least 5.5: 4.5, preferably at least 6: 4, more preferably at least 7: Exist at 3.

  According to the present invention, the proportion of surfactant of this general formula is 49% by weight, based on all surfactants present (ie surfactants of this general formula and optionally present). It is as follows. This ratio is preferably 30% by mass or less.

  The mixture used according to the invention can preferably be used for surfactant flooding of the deposit. This is particularly suitable for Winsor type III microemulsion flooding (Winsor type III range, or flooding in the presence of a bicontinuous microemulsion phase). The technique of microemulsion flooding has already been described in detail above.

In addition to the surfactant, the formulation may contain further ingredients such as C _4-to C ₈ alcohols and / or basic salts (so-called “alkaline surfactant flooding”). Such additives are used, for example, to reduce retention in the formulation. The ratio of alcohol to the total amount of surfactant used is usually at least 1: 1, however, a considerable excess of alcohol can also be used. The amount of basic salt is typically in the range of 0.1% to 5% by weight.

  The deposit to which the method is applied has a temperature of at least 10 ° C, such as 10 to 150 ° C, preferably at least 15 ° C to 120 ° C, more preferably 15 to 90 ° C. The total concentration of all surfactants together is 0.05-5% by weight, preferably 0.1-2.5% by weight, based on the total amount of aqueous surfactant formulation. Those skilled in the art will make an appropriate selection according to the desired properties, in particular the conditions of the mineral oil formation (mineral oil structure). Here, it is clear to those skilled in the art that the concentration of the surfactant changes after injection into the formation (structure). This is because the formulation is miscible with formation water or the surfactant can be absorbed onto the solid surface of the formation. It is a great advantage for the mixtures used according to the invention that the surfactant reduces the interfacial tension particularly well while at the same time the surfactant dissolves to form a clear solution.

  It is naturally possible and recommended to first produce a concentrate (the concentrate is only diluted in situ to the desired concentration for injection into the formation). Usually, the total concentration of surfactants in such concentrates is 10 to 45% by weight.

The following examples illustrate the invention in detail:
Part I: Synthesis of surfactants
Common method 1: Alkylation using KOH catalyst In a 2 l autoclave, the alcohol to be alkoxylated (1.0 eq) was mixed with an aqueous KOH solution containing 50% by weight KOH. The amount of KOH is 0.3% by weight of the product to be produced. During stirring, dehydration was carried out at 100 ° C. and 20 mbar for 2 hours. Then, it purged three times using N _2, to set the supply pressure of about 1.3 bar N _2, and the temperature was elevated 120 to 130 ° C.. The alkylene oxide was metered in while maintaining the temperature in the range 125 ° C. to 135 ° C. (for ethylene oxide) or 130 ° C. to 140 ° C. (for propylene oxide). The mixture was then stirred for an additional 5 hours at 125-135 ° C, purged with N ₂ , cooled to 70 ° C, and the reactor was emptied. The basic crude product was neutralized using acetic acid. Alternatively, neutralization can be performed by using commercially available magnesium silicate and then filtering off. ¹ H NMR spectra in CDCl ₃ , gel permeation chromatography, and OH number measurements were used to characterize the pale product and determine yield.

Common method 2: Sulfation using chlorosulfonic acid In a 1 l round bottom flask, the alkyl alkoxylate to be sulfated (1.0 eq) is added in 1.5 times the amount of dichloromethane (based on% by weight). And cooled to 5-10 ° C. Thereafter, chlorosulfonic acid (1.1 eq) was added dropwise such that the temperature did not exceed 10 ° C. The mixture was allowed to warm to room temperature and stirred at this temperature for 4 hours under N ₂ flow (before the above reaction mixture was added dropwise and added to half volume NaOH aqueous solution at a maximum of 15 ° C.). The amount of NaOH was calculated to be slightly in excess based on the chlorosulfonic acid used. The resulting pH is about pH 9-10. Dichloromethane was removed at maximum 50 ° C. (using a rotary evaporator under mild vacuum).

¹ HNMR was used to characterize the product and measure the water content of the solution (approximately 70%).

Common method 3: Alkoxylation of amine In a 2 l autoclave, the primary amine to be alkoxylated (1.0 eq) was mixed with a small amount of water (0.1 eq). Then, purged three times using N _2, set the initial pressure of about 1.3 bar N _2, and the temperature was elevated 120 to 130 ° C.. 2.0 eq of alkylene oxide was metered in while maintaining the temperature in the range of 125 ° C to 135 ° C. The mixture was then stirred for an additional 5 hours at 125-135 ° C, purged with N ₂ , cooled to 70 ° C, and the reactor was emptied. The basic crude product was neutralized using acetic acid. ¹ H NMR spectra in CDCl ₃ , gel permeation chromatography, and OH number measurements were used to characterize the pale product and to determine the amine number and yield.

Optionally (optionally) the amine reacted with 2.0 eq of alkylene oxide was mixed with aqueous KOH (containing 50% KOH). The amount of KOH is 0.3% by weight of the product produced. The mixture was dehydrated at 100 ° C. and 20 mbar for 2 hours. Then, purged three times using N _2, set the initial pressure of about 1.3 bar N _2, and the temperature was elevated 120 to 130 ° C.. The alkylene oxide was metered in while maintaining the temperature in the range 125 ° C. to 135 ° C. (for ethylene oxide) or 130 ° C. to 140 ° C. (for propylene oxide). The mixture was then stirred for an additional 5 hours at 125-135 ° C, purged with N ₂ , cooled to 70 ° C, and the reactor was emptied. ¹ H NMR spectra in CDCl ₃ , gel permeation chromatography, and OH and amine titrations were used to characterize the pale product and determine the yield.

Common Method 4: Amine, Quaternization with Dimethyl Sulfate A 2 liter glass flask was initially charged with the amine to be quaternized (1.0 eq) (this amine was optionally the same amount). Diluted with water). Next, while stirring, dimethyl sulfate (1.0 eq) was added dropwise (so that the temperature did not exceed 60 ° C.) and added slowly. Conversion (rate) was measured using the amine number. Stirring was continued until the degree of quaternization reached 95% or higher. Optionally, a small excess of dimethyl sulfate (0.1 eq) can be used. Excess dimethyl sulfate can be destroyed by simply boiling with water. ¹ H NMR spectra in CDCl ₃ , gel permeation chromatography, and amine titration were used to characterize the pale product and determine the yield.

The following alcohols and amines were used for the synthesis:

Performance Test The resulting surfactant was used to perform the following test (to evaluate its stability for producing tertiary mineral oil).
a) Solubility Alkyl alkoxysulfates and cationic surfactants were dissolved at room temperature in salted infused water or product water from sediment (total concentration 500-3000 ppm) and the solution brought to deposition temperature. Optionally, butyl diethylene glycol (BDG) was added. After 24 hours, the samples were visually evaluated and used further only when a clear solution was present. The two sediment injection waters had a salinity of 4000-30000 ppm of TDS (total dissolved salt). The deposition temperatures were 18 ° C. and 32 ° C., respectively.
b) Interfacial tension In addition, the surface tension of two dead crude oils (approximately 14 APIs each) and the original infused water containing salinity was applied to the spinning drop method at 18 ° C and 32 ° C deposition temperatures. Used to measure directly. For this purpose, the surfactant solution prepared in a) was used. Oil droplets were introduced into the clear (clear) solution at the deposition temperature and the interfacial tension was read after 2 hours.

Results The results are shown in Tables 1-6.

  Table 1 Solubility in injected water at 18 ° C

  As can be seen in Table 1, there are several combinations that result in a clear surfactant formulation under the given conditions.

  Table 2 Measurement of crude oil I and injected water at 18 ° C

  However, as compared to Table 2, it is noted that cationic surfactants based on groups having 12 carbon atoms give considerably worse (poor) interfacial tension compared to that of Example 6. The This was surprising. This is because surfactants with relatively long alkyl groups typically provide better interface tuning. As can be seen in Example 7, the claimed (claimed) surfactant is not only in the case of low salinity (Example 6, total salt content 12500 ppm), but also high salinity with a total salt content of about 24300 ppm. Even the content gives an interfacial tension of <0.01 mNm.

  Table 3 Solubility in injected water at 18 ° C

  In Table 3, there is no solubility problem even when using a surfactant formulation that includes a relatively highly ethoxylated cationic surfactant.

  Table 4 Measurement with crude oil I and injected water at 18 ° C

  As can be seen in Table 4, the combination of alkyl alkoxy sulfate and a relatively highly ethoxylated cationic surfactant has an interfacial tension of <0.01 mNm / m over a wide range of salinities. Yes.

  Table 5 Solubility in injected water at 32 ° C

  In Table 5, the solubility of the surfactant formulation was observed (considered) for deposits with high temperatures (32 ° C. instead of 18 ° C.). In addition to the previous tests, the formulation contains a base in the form of NaOH.

  Table 6 Measurement with crude oil II and injected water at 32 ° C

  As can be seen in Table 6, with the aid of a cationic cosurfactant having an alkyl group with 6 to 10 carbon atoms, as low as 0.02 mNm or less (Examples 2 to 4) Interfacial tension can be achieved. The comparatively long chain cationic surfactant in Comparative Example C1 shows an interfacial tension that is one step higher in grade.

Claims (13)

General formula R ¹ N ⁺ (R ² ) _m (R ³ ) _n (R ⁴ ) X ⁻
(However,
R ¹ is a linear or branched, saturated or unsaturated aliphatic and / or aromatic hydrocarbon group having 6 to 10 carbon atoms,
R ² and R ³ are each independently methyl, ethyl, and benzyl, or ethyleneoxy, propyleneoxy and / or butyleneoxy and / or pentyleneoxy;
R ⁴ is an alkyl group having 1 to 4 carbon atoms, or a hydroxyalkyl group, a benzyl group, or a phenyl-CH ₂ —CH ₂ —, or a phenyl-CH (CH ₃ ) — group,
m is 1-8, and n is 1-8, and the sum of m + n is in the range of 2-8, and X is an anion)
Surfactants. The surfactant according to claim 1, wherein R ² and R ³ are each independently methyl, ethyl, or benzyl, and n = m = 1. The surfactant according to claim 1, wherein R ² and R ³ are each ethyleneoxy, and R ⁴ is methyl or ethyl.   The surfactant according to claim 1 or 3, wherein the sum of n + m is in the range of 2-5. General formula R ¹ N ⁺ (R ² ) _m (R ³ ) _n (R ⁴ ) X ⁻
(However,
R ¹ is a linear or branched, saturated or unsaturated aliphatic and / or aromatic hydrocarbon group having 6 to 10 carbon atoms,
R ² and R ³ are each independently methyl, ethyl, and benzyl, or ethyleneoxy, propyleneoxy and / or butyleneoxy and / or pentyleneoxy;
R ⁴ is an alkyl group having 1 to 4 carbon atoms, or a hydroxyalkyl group, a benzyl group, or a phenyl-CH ₂ —CH ₂ —, or a phenyl-CH (CH ₃ ) — group,
m is 1-8, and n is 1-8, and the sum of m + n is in the range of 2-8, and X is an anion)
A surfactant formulation comprising at least one surfactant. The surfactant formulation of claim 5, wherein R ² and R ³ are each independently methyl, ethyl, or benzyl, and n = m = 1.   The surfactant according to claim 5 or 6, characterized in that the combined concentration of all the surfactants is 0.05 to 5% by weight relative to the total amount of the aqueous surfactant formulation. Formulation. A method for producing mineral oil using Winsor type III microemulsion flooding, comprising:
In order to reduce the interfacial tension between oil and water to <0.1 mN / m, an aqueous surfactant formulation comprising at least one ionic surfactant is passed through at least one injection hole to form a mineral oil deposit. And injecting the crude oil from the deposit through the at least one production hole;
The surfactant formulation has the general formula R ¹ N ⁺ (R ² ) _m (R ³ ) _n (R ⁴ ) X ⁻
(However,
R ¹ is a linear or branched, saturated or unsaturated aliphatic and / or aromatic hydrocarbon group having 6 to 10 carbon atoms,
R ² and R ³ are each independently methyl, ethyl, and benzyl, or ethyleneoxy, propyleneoxy and / or butyleneoxy and / or pentyleneoxy;
R ⁴ is an alkyl group having 1 to 4 carbon atoms, or a hydroxyalkyl group, a benzyl group, or a phenyl-CH ₂ —CH ₂ —, or a phenyl-CH (CH ₃ ) — group,
m is 1-8, and n is 1-8, and the sum of m + n is in the range of 2-8, and X is an anion)
A process for producing a mineral oil comprising at least one surfactant.   The method for producing a mineral oil according to claim 8, wherein the sum of m + n is in the range of 2-5. R ² and R ³ are each independently methyl, ethyl, or benzyl, and method for producing the mineral oil according to claim 9, characterized in that a n = m = 1.   The aqueous surfactant formulation comprises at least one alkyl alkoxy sulfate or alkyl alkoxy sulfonated type anionic surfactant, the anionic surfactant being greater than the amount of cationic surfactant described. 11. A process for producing a mineral oil according to any one of claims 8 to 10, characterized in that it is present in a large amount in an aqueous surfactant formulation.   The aqueous surfactant formulation also includes an alkylaryl sulfonate type anionic surfactant, the anionic surfactant in an amount greater than the amount of the cationic surfactant described, the aqueous surfactant 11. A method for producing a mineral oil according to any one of claims 8-10, characterized in that it is present in a formulation.   12. The concentration of all surfactants combined is 0.05 to 5% by weight, based on the total amount of aqueous surfactant formulation. A method for producing the mineral oil described in 1.